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Wednesday, April 9, 2025

Carcinogen

From Wikipedia, the free encyclopedia
https://en.wikipedia.org/wiki/Carcinogen
 
A carcinogen (/kɑːrˈsɪnəən/) is any agent that promotes the development of cancer. Carcinogens can include synthetic chemicals, naturally occurring substances, physical agents such as ionizing and non-ionizing radiation, and biologic agents such as viruses and bacteria. Most carcinogens act by creating mutations in DNA that disrupt a cell's normal processes for regulating growth, leading to uncontrolled cellular proliferation. This occurs when the cell's DNA repair processes fail to identify DNA damage allowing the defect to be passed down to daughter cells. The damage accumulates over time. This is typically a multi-step process during which the regulatory mechanisms within the cell are gradually dismantled allowing for unchecked cellular division.

The specific mechanisms for carcinogenic activity is unique to each agent and cell type. Carcinogens can be broadly categorized, however, as activation-dependent and activation-independent which relate to the agent's ability to engage directly with DNA. Activation-dependent agents are relatively inert in their original form, but are bioactivated in the body into metabolites or intermediaries capable of damaging human DNA. These are also known as "indirect-acting" carcinogens. Examples of activation-dependent carcinogens include polycyclic aromatic hydrocarbons (PAHs), heterocyclic aromatic amines, and mycotoxins. Activation-independent carcinogens, or "direct-acting" carcinogens, are those that are capable of directly damaging DNA without any modification to their molecular structure. These agents typically include electrophilic groups that react readily with the net negative charge of DNA molecules. Examples of activation-independent carcinogens include ultraviolet light, ionizing radiation and alkylating agents.

The time from exposure to a carcinogen to the development of cancer is known as the latency period. For most solid tumors in humans the latency period is between 10 and 40 years depending on cancer type. For blood cancers, the latency period may be as short as two. Due to prolonged latency periods identification of carcinogens can be challenging.

A number of organizations review and evaluate the cumulative scientific evidence regarding the potential carcinogenicity of specific substances. Foremost among these is the International Agency for Research on Cancer (IARC). IARC routinely publishes monographs in which specific substances are evaluated for their potential carcinogenicity to humans and subsequently categorized into one of four groupings: Group 1: Carcinogenic to humans, Group 2A: Probably carcinogenic to humans, Group 2B: Possibly carcinogenic to humans and Group 3: Not classifiable as to its carcinogenicity to humans. Other organizations that evaluate the carcinogenicity of substances include the National Toxicology Program of the US Public Health Service, NIOSH, the American Conference of Governmental Industrial Hygienists and others.

There are numerous sources of exposures to carcinogens including ultraviolet radiation from the sun, radon gas emitted in residential basements, environmental contaminants such as chlordecone, cigarette smoke and ingestion of some types of foods such as alcohol and processed meats. Occupational exposures represent a major source of carcinogens with an estimated 666,000 annual fatalities worldwide attributable to work related cancers. According to NIOSH, 3-6% of cancers worldwide are due to occupational exposures. Well established occupational carcinogens include vinyl chloride and hemangiosarcoma of the liver, benzene and leukemia, aniline dyes and bladder cancer, asbestos and mesothelioma, polycyclic aromatic hydrocarbons and scrotal cancer among chimney sweeps to name a few.

Radiation

Ionizing Radiation

CERCLA identifies all radionuclides as carcinogens, although the nature of the emitted radiation (alpha, beta, gamma, or neutron and the radioactive strength), its consequent capacity to cause ionization in tissues, and the magnitude of radiation exposure, determine the potential hazard. Carcinogenicity of radiation depends on the type of radiation, type of exposure, and penetration. For example, alpha radiation has low penetration and is not a hazard outside the body, but emitters are carcinogenic when inhaled or ingested. For example, Thorotrast, a (incidentally radioactive) suspension previously used as a contrast medium in x-ray diagnostics, is a potent human carcinogen known because of its retention within various organs and persistent emission of alpha particles. Low-level ionizing radiation may induce irreparable DNA damage (leading to replicational and transcriptional errors needed for neoplasia or may trigger viral interactions) leading to pre-mature aging and cancer.

Non-ionizing radiation

Not all types of electromagnetic radiation are carcinogenic. Low-energy waves on the electromagnetic spectrum including radio waves, microwaves, infrared radiation and visible light are thought not to be, because they have insufficient energy to break chemical bonds. Evidence for carcinogenic effects of non-ionizing radiation is generally inconclusive, though there are some documented cases of radar technicians with prolonged high exposure experiencing significantly higher cancer incidence.

Higher-energy radiation, including ultraviolet radiation (present in sunlight) generally is carcinogenic, if received in sufficient doses. For most people, ultraviolet radiations from sunlight is the most common cause of skin cancer. In Australia, where people with pale skin are often exposed to strong sunlight, melanoma is the most common cancer diagnosed in people aged 15–44 years.

Substances or foods irradiated with electrons or electromagnetic radiation (such as microwave, X-ray or gamma) are not carcinogenic. In contrast, non-electromagnetic neutron radiation produced inside nuclear reactors can produce secondary radiation through nuclear transmutation.

Common carcinogens associated with food

Alcohol

Alcohol is a carcinogen of the head and neck, esophagus, liver, colon and rectum, and breast. It has a synergistic effect with tobacco smoke in the development of head and neck cancers. In the United States approximately 6% of cancers and 4% of cancer deaths are attributable to alcohol use.

Processed meats

Chemicals used in processed and cured meat such as some brands of bacon, sausages and ham may produce carcinogens. For example, nitrites used as food preservatives in cured meat such as bacon have also been noted as being carcinogenic with demographic links, but not causation, to colon cancer.

Meats cooked at high temperatures

Cooking food at high temperatures, for example grilling or barbecuing meats, may also lead to the formation of minute quantities of many potent carcinogens that are comparable to those found in cigarette smoke (i.e., benzo[a]pyrene). Charring of food looks like coking and tobacco pyrolysis, and produces carcinogens. There are several carcinogenic pyrolysis products, such as polynuclear aromatic hydrocarbons, which are converted by human enzymes into epoxides, which attach permanently to DNA. Pre-cooking meats in a microwave oven for 2–3 minutes before grilling shortens the time on the hot pan, and removes heterocyclic amine (HCA) precursors, which can help minimize the formation of these carcinogens.

Acrylamide in foods

Frying, grilling or broiling food at high temperatures, especially starchy foods, until a toasted crust is formed generates acrylamides. This discovery in 2002 led to international health concerns. Subsequent research has however found that it is not likely that the acrylamides in burnt or well-cooked food cause cancer in humans; Cancer Research UK categorizes the idea that burnt food causes cancer as a "myth".

Biologic Agents

Several biologic agents are known carcinogens.

Aflatoxin B1, a toxin produced by the fungus Aspergillus flavus which is a common contaminant of stored grains and nuts is a known cause of hepatocellular cancer. The bacteria H. Pylori is known to cause stomach cancer and MALT lymphoma. Hepatitis B and C are associated with the development of hepatocellular cancer. HPV is the primary cause of cervical cancer.

Cigarette smoke

Tobacco smoke contains at least 70 known carcinogens and is implicated in the development of numerous types of cancers including cancers of the lung, larynx, esophagus, stomach, kidney, pancreas, liver, bladder, cervix, colon, rectum and blood. Potent carcinogens found in cigarette smoke include polycyclic aromatic hydrocarbons (PAH, such as benzo(a)pyrene), benzene, and nitrosamine.

Occupational carcinogens

Given that populations of workers are more likely to have consistent, often high level exposures to chemicals rarely encountered in normal life, much of the evidence for the carcinogenicity of specific agents is derived from studies of workers.

Selected carcinogens

Carcinogen Associated cancer sites or types Occupational uses or sources
Arsenic and its compounds
  • Smelting byproduct
  • Component of:
    • Alloys
    • Electrical and semiconductor devices
    • Medications (e.g. melarsoprol)
    • Herbicides
    • Fungicides
    • Animal dips
    • Drinking water from contaminated aquifers.
Asbestos

Not in widespread use, but found in:

  • Constructions
    • Roofing papers
    • Floor tiles
  • Fire-resistant textiles
  • Friction linings (brake pads) (only outside Europe)
    • Replacement friction linings for automobiles still may contain asbestos
Benzene
Beryllium and its compounds
  • Lung
  • Lightweight alloys
    • Aerospace applications
    • Nuclear reactors
Cadmium and its compounds
Hexavalent chromium(VI) compounds
  • Lung
  • Paints
  • Pigments
  • Preservatives
Nitrosamines
  • Lung
  • Esophagus
  • Liver
Ethylene oxide
  • Leukemia
Nickel
  • Nickel plating
  • Ferrous alloys
  • Ceramics
  • Batteries
  • Stainless-steel welding byproduct
Radon and its decay products
  • Lung
  • Uranium decay
    • Quarries and mines
    • Cellars and poorly ventilated places
Vinyl chloride
Shift work that involves

circadian disruption


Involuntary smoking (Passive smoking)
  • Lung

Radium-226, Radium-224,
Plutonium-238, Plutonium-239
and other alpha particle
emitters with high atomic weight
Unless otherwise specified, ref is:[34]

Others

Mechanisms of carcinogenicity

Carcinogens can be classified as genotoxic or nongenotoxic. Genotoxins cause irreversible genetic damage or mutations by binding to DNA. Genotoxins include chemical agents like N-nitroso-N-methylurea (NMU) or non-chemical agents such as ultraviolet light and ionizing radiation. Certain viruses can also act as carcinogens by interacting with DNA.

Nongenotoxins do not directly affect DNA but act in other ways to promote growth. These include hormones and some organic compounds.

Classification

Approximate equivalences
between classification schemes
IARC GHS NTP ACGIH EU
Group 1 Cat. 1A Known A1 Cat. 1A
Group 2A Cat. 1B Reasonably
suspected
A2 Cat. 1B
Group 2B
Cat. 2   A3 Cat. 2
Group 3
  A4  
Group 4 A5

International Agency for Research on Cancer

The International Agency for Research on Cancer (IARC) is an intergovernmental agency established in 1965, which forms part of the World Health Organization of the United Nations. It is based in Lyon, France. Since 1971 it has published a series of Monographs on the Evaluation of Carcinogenic Risks to Humans that have been highly influential in the classification of possible carcinogens.

  • Group 1: the agent (mixture) is carcinogenic to humans. The exposure circumstance entails exposures that are carcinogenic to humans.
  • Group 2A: the agent (mixture) is most likely (product more likely to be) carcinogenic to humans. The exposure circumstance entails exposures that are probably carcinogenic to humans.
  • Group 2B: the agent (mixture) is possibly (chance of product being) carcinogenic to humans. The exposure circumstance entails exposures that are possibly carcinogenic to humans.
  • Group 3: the agent (mixture or exposure circumstance) is not classifiable as to its carcinogenicity to humans.
  • Group 4: the agent (mixture) is most likely not carcinogenic to humans.

Globally Harmonized System

The Globally Harmonized System of Classification and Labelling of Chemicals (GHS) is a United Nations initiative to attempt to harmonize the different systems of assessing chemical risk which currently exist (as of March 2009) around the world. It classifies carcinogens into two categories, of which the first may be divided again into subcategories if so desired by the competent regulatory authority:

  • Category 1: known or presumed to have carcinogenic potential for humans
    • Category 1A: the assessment is based primarily on human evidence
    • Category 1B: the assessment is based primarily on animal evidence
  • Category 2: suspected human carcinogens

U.S. National Toxicology Program

The National Toxicology Program of the U.S. Department of Health and Human Services is mandated to produce a biennial Report on Carcinogens. As of August 2024, the latest edition was the 15th report (2021). It classifies carcinogens into two groups:

  • Known to be a human carcinogen
  • Reasonably anticipated to be a human carcinogen

American Conference of Governmental Industrial Hygienists

The American Conference of Governmental Industrial Hygienists (ACGIH) is a private organization best known for its publication of threshold limit values (TLVs) for occupational exposure and monographs on workplace chemical hazards. It assesses carcinogenicity as part of a wider assessment of the occupational hazards of chemicals.

  • Group A1: Confirmed human carcinogen
  • Group A2: Suspected human carcinogen
  • Group A3: Confirmed animal carcinogen with unknown relevance to humans
  • Group A4: Not classifiable as a human carcinogen
  • Group A5: Not suspected as a human carcinogen

European Union

The European Union classification of carcinogens is contained in the Regulation (EC) No 1272/2008. It consists of three categories:

  • Category 1A: Carcinogenic
  • Category 1B: May cause cancer
  • Category 2: Suspected of causing cancer

The former European Union classification of carcinogens was contained in the Dangerous Substances Directive and the Dangerous Preparations Directive. It also consisted of three categories:

  • Category 1: Substances known to be carcinogenic to humans.
  • Category 2: Substances which should be regarded as if they are carcinogenic to humans.
  • Category 3: Substances which cause concern for humans, owing to possible carcinogenic effects but in respect of which the available information is not adequate for making a satisfactory assessment.

This assessment scheme is being phased out in favor of the GHS scheme (see above), to which it is very close in category definitions.

Safe Work Australia

Under a previous name, the NOHSC, in 1999 Safe Work Australia published the Approved Criteria for Classifying Hazardous Substances [NOHSC:1008(1999)]. Section 4.76 of this document outlines the criteria for classifying carcinogens as approved by the Australian government. This classification consists of three categories:

  • Category 1: Substances known to be carcinogenic to humans.
  • Category 2: Substances that should be regarded as if they were carcinogenic to humans.
  • Category 3: Substances that have possible carcinogenic effects in humans but about which there is insufficient information to make an assessment.

Major carcinogens implicated in the four most common cancers worldwide

In this section, the carcinogens implicated as the main causative agents of the four most common cancers worldwide are briefly described. These four cancers are lung, breast, colon, and stomach cancers. Together they account for about 41% of worldwide cancer incidence and 42% of cancer deaths (for more detailed information on the carcinogens implicated in these and other cancers, see references).

Lung cancer

Lung cancer (pulmonary carcinoma) is the most common cancer in the world, both in terms of cases (1.6 million cases; 12.7% of total cancer cases) and deaths (1.4 million deaths; 18.2% of total cancer deaths). Lung cancer is largely caused by tobacco smoke. Risk estimates for lung cancer in the United States indicate that tobacco smoke is responsible for 90% of lung cancers. Other factors are implicated in lung cancer, and these factors can interact synergistically with smoking so that total attributable risk adds up to more than 100%. These factors include occupational exposure to carcinogens (about 9-15%), radon (10%) and outdoor air pollution (1-2%).

Tobacco smoke is a complex mixture of more than 5,300 identified chemicals. The most important carcinogens in tobacco smoke have been determined by a "Margin of Exposure" approach. Using this approach, the most important tumorigenic compounds in tobacco smoke were, in order of importance, acrolein, formaldehyde, acrylonitrile, 1,3-butadiene, cadmium, acetaldehyde, ethylene oxide, and isoprene. Most of these compounds cause DNA damage by forming DNA adducts or by inducing other alterations in DNA.[citation needed] DNA damages are subject to error-prone DNA repair or can cause replication errors. Such errors in repair or replication can result in mutations in tumor suppressor genes or oncogenes leading to cancer.

Breast cancer

Breast cancer is the second most common cancer [(1.4 million cases, 10.9%), but ranks 5th as cause of death (458,000, 6.1%)]. Increased risk of breast cancer is associated with persistently elevated blood levels of estrogen. Estrogen appears to contribute to breast carcinogenesis by three processes; (1) the metabolism of estrogen to genotoxic, mutagenic carcinogens, (2) the stimulation of tissue growth, and (3) the repression of phase II detoxification enzymes that metabolize ROS leading to increased oxidative DNA damage.

The major estrogen in humans, estradiol, can be metabolized to quinone derivatives that form adducts with DNA. These derivatives can cause depurination, the removal of bases from the phosphodiester backbone of DNA, followed by inaccurate repair or replication of the apurinic site leading to mutation and eventually cancer. This genotoxic mechanism may interact in synergy with estrogen receptor-mediated, persistent cell proliferation to ultimately cause breast cancer. Genetic background, dietary practices and environmental factors also likely contribute to the incidence of DNA damage and breast cancer risk.

Consumption of alcohol has also been linked to an increased risk for breast cancer.

Colon cancer

Colorectal cancer is the third most common cancer [1.2 million cases (9.4%), 608,000 deaths (8.0%)]. Tobacco smoke may be responsible for up to 20% of colorectal cancers in the United States. In addition, substantial evidence implicates bile acids as an important factor in colon cancer. Twelve studies (summarized in Bernstein et al.) indicate that the bile acids deoxycholic acid (DCA) or lithocholic acid (LCA) induce production of DNA-damaging reactive oxygen species or reactive nitrogen species in human or animal colon cells. Furthermore, 14 studies showed that DCA and LCA induce DNA damage in colon cells. Also 27 studies reported that bile acids cause programmed cell death (apoptosis).

Increased apoptosis can result in selective survival of cells that are resistant to induction of apoptosis.[52] Colon cells with reduced ability to undergo apoptosis in response to DNA damage would tend to accumulate mutations, and such cells may give rise to colon cancer. Epidemiologic studies have found that fecal bile acid concentrations are increased in populations with a high incidence of colon cancer. Dietary increases in total fat or saturated fat result in elevated DCA and LCA in feces and elevated exposure of the colon epithelium to these bile acids. When the bile acid DCA was added to the standard diet of wild-type mice invasive colon cancer was induced in 56% of the mice after 8 to 10 months. Overall, the available evidence indicates that DCA and LCA are centrally important DNA-damaging carcinogens in colon cancer.

Stomach cancer

Stomach cancer is the fourth most common cancer [990,000 cases (7.8%), 738,000 deaths (9.7%)]. Helicobacter pylori infection is the main causative factor in stomach cancer. Chronic gastritis (inflammation) caused by H. pylori is often long-standing if not treated. Infection of gastric epithelial cells with H. pylori results in increased production of reactive oxygen species (ROS). ROS cause oxidative DNA damage including the major base alteration 8-hydroxydeoxyguanosine (8-OHdG). 8-OHdG resulting from ROS is increased in chronic gastritis. The altered DNA base can cause errors during DNA replication that have mutagenic and carcinogenic potential. Thus H. pylori-induced ROS appear to be the major carcinogens in stomach cancer because they cause oxidative DNA damage leading to carcinogenic mutations.

Diet is also thought to be a contributing factor in stomach cancer: in Japan, where very salty pickled foods are popular, the incidence of stomach cancer is high. Preserved meat such as bacon, sausages, and ham increases the risk, while a diet rich in fresh fruit, vegetables, peas, beans, grains, nuts, seeds, herbs, and spices will reduce the risk. The risk also increases with age.

Gastritis

From Wikipedia, the free encyclopedia
 
Gastritis
Micrograph showing gastritis. H&E stain.
SpecialtyGastroenterology
SymptomsUpper abdominal pain, nausea, vomiting, bloating, loss of appetite, heartburn
ComplicationsBleeding, stomach ulcers, stomach tumors, pernicious anemia
DurationShort or long term
CausesHelicobacter pylori, NSAIDs, alcohol, tobacco, cocaine, viruses, parasites, autoimmune
Diagnostic methodEndoscopy, upper gastrointestinal series, blood tests, stool tests
Differential diagnosisMyocardial infarction, inflammation of the pancreas, gallbladder problems, peptic ulcer disease
TreatmentAntacids, H2 blockers, proton pump inhibitors, antibiotics, sucralfate, bismuth subsalicylate, antiemetics
Frequency~50% of people
Deaths50,000 (2015)

Gastritis is the inflammation of the lining of the stomach. It may occur as a short episode or may be of a long duration. There may be no symptoms but, when symptoms are present, the most common is upper abdominal pain (see dyspepsia). Other possible symptoms include nausea and vomiting, bloating, loss of appetite and heartburn. Complications may include stomach bleeding, stomach ulcers, and stomach tumors. When due to autoimmune problems, low red blood cells due to not enough vitamin B12 may occur, a condition known as pernicious anemia.

Common causes include infection with Helicobacter pylori and use of nonsteroidal anti-inflammatory drugs (NSAIDs). When caused by H. pylori this is now termed Helicobacter pylori induced gastritis, and included as a listed disease in ICD11. Less common causes include alcohol, smoking, cocaine, severe illness, autoimmune problems, radiation therapy and Crohn's disease. Endoscopy, a type of X-ray known as an upper gastrointestinal series, blood tests, and stool tests may help with diagnosis. Other conditions with similar symptoms include inflammation of the pancreas, gallbladder problems, and peptic ulcer disease.

Prevention is by avoiding things that cause the disease. Treatment includes medications such as antacids, H2 blockers, or proton pump inhibitors. During an acute attack drinking viscous lidocaine may help. If gastritis is due to NSAIDs these may be stopped. If H. pylori is present it may be treated with a combination of antibiotics such as amoxicillin and clarithromycin. For those with pernicious anemia, vitamin B12 supplements are recommended either by mouth or by injection. People are usually advised to avoid foods that bother them.

Gastritis is believed to affect about half of people worldwide. In 2013 there were approximately 90 million new cases of the condition. As people get older the disease becomes more common. It, along with a similar condition in the first part of the intestines known as duodenitis, resulted in 50,000 deaths in 2015. H. pylori was first discovered in 1981 by Barry Marshall and Robin Warren.

Signs and symptoms

A peptic ulcer may accompany gastritis. Endoscopic image.

Many people with gastritis experience no symptoms at all. However, upper central abdominal pain is the most common symptom; the pain may be dull, vague, burning, aching, gnawing, sore, or sharp. Pain is usually located in the upper central portion of the abdomen, but it may occur anywhere from the upper left portion of the abdomen around to the back.

Other signs and symptoms may include the following:

Causes

There are two categories of gastritis depending on the cause of the disease. There is erosive gastritis, for which the common causes are stress, alcohol, some drugs, such as aspirin and other nonsteroidal anti-inflammatory drugs (NSAIDs), and Crohn's disease. And, there is non-erosive gastritis, for which the most common cause is a Helicobacter pylori infection. 

Helicobacter pylori

Helicobacter pylori colonizes the stomachs of more than half of the world's population, and the infection continues to play a key role in the pathogenesis of a number of gastroduodenal diseases. Colonization of the gastric mucosa with Helicobacter pylori results in the development of chronic gastritis in infected individuals and, in a subset of patients, chronic gastritis progresses to complications (e.g., ulcer disease, stomach cancers, and some distinct extragastric disorders). Gastritis caused by H. pylori infection is termed Helicobacter pylori induced gastritis, and listed as a disease in ICD11. More than 80% of individuals infected with the bacterium are asymptomatic and it has been postulated that it may play an important role in the natural stomach ecology.

Critical illness

Gastritis may also develop after major surgery or traumatic injury ("Cushing ulcer"), burns ("Curling ulcer"), or severe infections. Gastritis may also occur in those who have had weight loss surgery resulting in the banding or reconstruction of the digestive tract.

Diet

Evidence does not support a role for specific foods, including spicy foods and coffee, in the development of peptic ulcers. People are usually advised to avoid foods that bother them. There is little specific advice on diet published by authoritative sources. The National Health Service of the United Kingdom advises avoiding spicy, acidic or fried foods which may irritate the stomach.

Pathophysiology

Acute

Early acute superficial gastritis: Marked neutrophilic infiltrates appear in the mucous neck region and lamina with a pit microabscess. This case was caused by Helicobacter pylori.

Acute erosive gastritis typically involves discrete foci of surface necrosis due to damage to mucosal defenses. NSAIDs inhibit cyclooxygenase-1, or COX-1, an enzyme responsible for the biosynthesis of eicosanoids in the stomach, which increases the possibility of peptic ulcers forming. Also, NSAIDs, such as aspirin, reduce a substance that protects the stomach called prostaglandin. These drugs used in a short period are not typically dangerous. However, regular use can lead to gastritis. Additionally, severe physiologic stress from sepsis, hypoxia, trauma, or surgery is also a common etiology for acute erosive gastritis, resulting in "stress ulcers". This form of gastritis can occur in more than 5% of hospitalized patients.

Also, alcohol consumption does not cause chronic gastritis. It does, however, erode the mucosal lining of the stomach; low doses of alcohol stimulate hydrochloric acid secretion. High doses of alcohol do not stimulate secretion of acid.

Chronic

Chronic gastritis refers to a wide range of problems of the gastric issues. The immune system makes proteins and antibodies that fight infections in the body to maintain a homeostatic condition. In some disorders the body targets the stomach as if it were a foreign protein or pathogen; it makes antibodies against, severely damages, and may even destroy the stomach or its lining. In some cases bile, normally used to aid digestion in the small intestine, will enter through the pyloric valve of the stomach if it has been removed during surgery or does not work properly, also leading to gastritis. Gastritis may also be caused by other medical conditions, including HIV/AIDS, Crohn's disease, certain connective tissue disorders, and liver or kidney failure. Since 1992, chronic gastritis lesions are classified according to the Sydney system.

Metaplasia

Mucous gland metaplasia, the reversible replacement of differentiated cells, occurs in the setting of severe damage of the gastric glands, which then waste away (atrophic gastritis) and are progressively replaced by mucous glands. Gastric ulcers may develop; it is unclear if they are the causes or the consequences. Intestinal metaplasia typically begins in response to chronic mucosal injury in the antrum and may extend to the body. Gastric mucosa cells change to resemble intestinal mucosa and may even assume absorptive characteristics. Intestinal metaplasia is classified histologically as complete or incomplete. With complete metaplasia, gastric mucosa is completely transformed into small-bowel mucosa, both histologically and functionally, with the ability to absorb nutrients and secrete peptides. In incomplete metaplasia, the epithelium assumes a histologic appearance closer to that of the large intestine and frequently exhibits dysplasia.

Diagnosis

Updated Sydney System for visual classification of gastritis on histopathology.

Often, a diagnosis can be made based on patients' description of their symptoms. Other methods which may be used to verify gastritis include:

  • Blood tests:
  • Urinalysis
  • Stool sample, to look for blood in the stool
  • X-rays
  • Endoscopy, to check for stomach lining inflammation and mucous erosion
  • Stomach biopsy, to test for gastritis and other conditions

The OLGA staging frame of chronic gastritis on histopathology. Atrophy is scored as the percentage of atrophic glands and scored on a four-tiered scale. No atrophy (0%) = score 0; mild atrophy (1–30%) = score 1; moderate atrophy (31–60%) = score 2; severe atrophy (>60%) = score 3. These scores (0–3) are used in the OLGA staging assessment in each 10 compartment:


Corpus
No atrophy
(score 0)
Mild atrophy
(score 1)
Moderate atrophy
(score 2)
Severe atrophy
(score 3)
Antrum
(including
incisura
angularis)
No atrophy (score 0) Stage 0 Stage I Stage II Stage II
Mild atrophy (score 1) Stage I Stage I Stage II Stage III
Moderate atrophy (score 2) Stage II Stage II Stage III Stage IV
Severe atrophy (score 3) Stage III Stage III Stage IV Stage IV

Treatment

Antacids are a common treatment for mild to medium gastritis. When antacids do not provide enough relief, medications such as H2 blockers and proton-pump inhibitors that help reduce the amount of acid are often prescribed.

Cytoprotective agents are designed to help protect the tissues that line the stomach and small intestine. They include the medications sucralfate and misoprostol. If NSAIDs are being taken regularly, one of these medications to protect the stomach may also be taken. Another cytoprotective agent is bismuth subsalicylate.

Several regimens are used to treat H. pylori infection. Most use a combination of two antibiotics and a proton pump inhibitor. Sometimes bismuth is added to the regimen.

History

In 1,000 A.D, Avicenna first gave the description of stomach cancer. In 1728, German physician Georg Ernst Stahl first coined the term "gastritis". Italian anatomical pathologist Giovanni Battista Morgagni further described the characteristics of gastric inflammation. He described the characteristics of erosive or ulcerative gastritis and erosive gastritis. Between 1808 and 1831, French physician François-Joseph-Victor Broussais gathered information from the autopsies of dead French soldiers. He described chronic gastritis as "Gastritide" and erroneously believed that gastritis was the cause of ascites, typhoid fever, and meningitis. In 1854, Charles Handfield Jones and Wilson Fox described the microscopic changes of stomach inner lining in gastritis which existed in diffuse and segmental forms. In 1855, Baron Carl von Rokitansky first described hypertrophic gastritis. In 1859, British physician, William Brinton first described about acute, subacute, and chronic gastritis. In 1870, Samuel Fenwick noted that pernicious anemia causes glandular atrophy in gastritis. German surgeon Georg Ernst Konjetzny noticed that both gastric ulcer and gastric cancer are the results of gastric inflammation. Shields Warren and Willam A. Meissner described the intestinal metaplasia of the stomach as a feature of chronic gastritis.

Tuesday, April 8, 2025

Female infanticide

From Wikipedia, the free encyclopedia
 
Female infanticide is the deliberate killing of newborn female children. Female infanticide is prevalent in several nations around the world. It has been argued that the low status in which women are viewed in patriarchal societies creates a bias against females. The modern practice of sex-selective abortion is also used to regulate gender ratios.

In 1978, anthropologist Laila Williamson, in a summary of data she had collated on how widespread infanticide was, found that infanticide had occurred on every continent and was carried out by groups ranging from hunter gatherers to highly developed societies, and that, rather than this practice being an exception, it has been commonplace. The practice has been documented among the Indigenous peoples of Australia, Northern Alaska and South Asia, and Barbara Miller argues the practice to be "almost universal", even in the Western world. Miller contends that female infanticide is commonplace in regions where women are not employed in agriculture and regions in which dowries are the norm. In 1871, in The Descent of Man, and Selection in Relation to Sex, Charles Darwin wrote that the practice was commonplace among the aboriginal tribes of Australia. Female infanticide is also closely linked to a lack of education and high poverty rates, which explains why it is widely prevalent in locations such as India, Pakistan, and West Africa.

In 1990, Amartya Sen writing in the New York Review of Books estimated that there were 100 million fewer women in Asia than would be expected, and that this number of "missing" women "tell[s] us, quietly, a terrible story of inequality and neglect leading to the excess mortality of women".

Regional occurrence

China

Matteo Ricci

China has a history of female infanticide spanning 2,000 years. With the arrival of Christian missionaries in the late sixteenth century, the missionaries discovered female infanticide was being practiced – newborns were seen thrown into rivers or onto rubbish piles. In the seventeenth century, Matteo Ricci documented that the practice occurred in several of China's provinces and that the primary reason for the practice was poverty.

In 19th-century China, female infanticide was widespread. Readings from Qing texts show a prevalence of the term nì nǚ ("to drown girls"), and drowning was the common method used to kill female children. Other methods used were suffocation and starvation. Leaving a child exposed to the elements was another method of killing an infant: the child would be placed in a basket which was then placed in a tree. Buddhist nunneries created "baby towers" for people to leave a child; it is however unclear as to whether the child was being left for adoption or if it had already died and was being left for burial. In 1845 in the province of Jiangxi, a missionary wrote that these children survived for up to two days while exposed to the elements, and that those passing by would pay no attention.

Chinese anti infanticide tract circa 1800.

The majority of China's provinces practiced female infanticide during the 19th century. In 1878, French Jesuit missionary Gabriel Palatre collected documents from 13 provinces, and the Annales de la Sainte-Enfance (Annals of the Holy Childhood) also found evidence of infanticide in Shanxi and Sichuan. According to the information collected by Palatre, the practice was more widely spread in the southeastern provinces and in the Lower Yangzi River region.

In China, the practice of female infanticide was not wholly condoned. Buddhism in particular was quite forceful in its condemnation of it. Buddhists wrote that the killing of young girls would bring bad karma; conversely, those who saved a young girl's life either through intervening or through presents of money or food would earn good karma, leading to a prosperous life, a long life and success for their sons. However the Buddhist belief in reincarnation meant that the death of an infant was not final, as the child would be reborn; this belief eased the guilt felt over female infanticide.

The Confucian attitude towards female infanticide was conflicted. By placing value on age over youth, Confucian filial piety lessened the value of children. The Confucian emphasis on the family led to increasing dowries which in turn led to a girl being far more expensive to raise than a boy, causing families to feel they could not afford as many daughters. The Confucian custom of keeping the male within the family meant that the money spent on a daughter's upbringing along with the dowry would be lost when she married, and as such girls were called "money-losing merchandise". Conversely the Confucian belief of Ren led Confucian intellectuals to support the idea that female infanticide was wrong and that the practice would upset the balance between yin and yang.

A white paper published by the Chinese government in 1980 stated that the practice of female infanticide was a "feudalistic evil". The state's official position on the practice is that it is a carryover from feudal times, and is not a result of the states one-child policy. Jing-Bao Nie argues however that it would be "inconceivable" to believe there is no link between the state's family planning policies and female infanticide.

India

A map of India's child sex ratio, 2011.

The dowry system in India is one given reason for female infanticide; over a time period spanning centuries it has become embedded within Indian culture. Although the state has taken steps to abolish the dowry system, the practice persists, and for poorer families in rural regions female infanticide and gender selective abortion is attributed to the fear of being unable to raise a suitable dowry and then being socially ostracized.

In 1789, during British colonial rule in India the British discovered that female infanticide in Uttar Pradesh was openly acknowledged. A letter from a magistrate who was stationed in the North West of India during this period spoke of the fact that for several hundred years no daughter had ever been raised in the strongholds of the Rajahs of Mynpoorie. In 1845, however the ruler at that time did keep a daughter alive after a district collector named Unwin intervened. A review of scholarship has shown that the majority of female infanticides in India during the colonial period occurred for the most part in the North West, and that although not all groups carried out this practice, it was indeed widespread. In 1870, after an investigation by the colonial authorities the practice was made illegal, with the Female Infanticide Prevention Act, 1870.

According to women's rights activist Donna Fernandes, some practices are so deeply embedded within Indian culture it is "almost impossible to do away with them", and she has said that India is undergoing a type of "female genocide". The United Nations has declared that India is the most deadly country for female children, and that in 2012, female children aged between 1 and 5 were 75 percent more likely to die as opposed to boys. The children's rights group CRY has estimated that of the 12 million females born yearly in India, 1 million will have died within their first year of life. During British rule, the practice of female infanticide in the Indian state of Tamil Nadu among the Kallars and the Todas was reported. More recently in June 1986, it was reported by India Today in a cover story Born to Die that female infanticide was still in practice in Usilampatti in southern Tamil Nadu. The practice was mostly prevalent among the dominant caste of the region, Kallars.

Pakistan

Despite this practice being punishable according to Islamic law, there have been cases of female infanticide in Pakistan due to a few reasons, for example, children being born out of wedlock and then killed to avoid the stigma of illegitimacy. Pakistan is still a male-dominated nation and remains a patriarchal society. In addition, the boys in the family are given preferential treatment, receiving food and medical care before the girls do. Having a child out of wedlock in Pakistan is culturally taboo. When women give birth to their babies, they often kill them to escape the shame or persecution. However, the ratio of female babies being killed in these cases is much higher than the boys because boys are much more valued. Infanticide is illegal in Pakistan. However, people do not report these cases, making it impossible for police to investigate. According to National Right to Live News, in 2017, only one case was actually reported, but 345 babies were found dead in Pakistan's capital between January 2017 and Spring of 2018.

Socio-economics

Eliminating females poses an issue, as this reduces the number of females that will be able to bear children. It also poses an issue with feelings of female worth, as families wanting to eradicate female babies teach the young girls in their society that they are inferior to the opposite sex, making it more likely that they have problems of lacking self-confidence and esteem. The dowry system has an effect on the families and poverty line, as some families struggle to pay a dowry while earning below the minimum wage.

As of 2017, Pakistani women earn less than their male counterparts, earning under a hundred rupees a month, and are often unable to receive an education that would allow them to have better working hours and pay. Some are also restricted to only working within the home, while men are allowed to do the majority of crop work and herding.

In many countries, female infanticide is associated with socio-economic struggles. A study done in India found three socio-economic reasons associated with female infanticide. The study found that economic utility indicates that boys are valued more than girls due to the fact that boys can work and bring in money to the household. Due to the sociocultural utility factor of female infanticide, for many cultures having a boy in the family is mandatory in order to carry out the legacy of the family line. There is also a religious factor in female infanticide. Many believe that men are the only ones that can provide, and sons are viewed as mandatory in order to kindle the funeral pyre of their late parents and to assist in the soul's salvation.

Solutions and programs

Non-Government Developmental Organizations (NGDOs) have gender awareness policies designed to prevent female discrimination all over the world. These NGDOs approach corporations in an attempt to educate those in the workforce on the pressing challenges women in society face. Other than increasing education regarding this issue, another noteworthy solution to female infanticide involves targeting the dowry system. Many societies oppose female children because of the heavy cost of dowry they would have to incur for a female. By reducing the financial burden on families, the eradication of the dowry system could therefore potentially reduce the apparent preference of male children as well as female infanticide rates.

Another way of decreasing female infanticide rates is by providing families with incentives to give birth to females. India's Girl Child Protection Scheme[31] is one such scheme that encourages female births by providing families with financial support if they give birth to female children and additional support to those families whose children receive an education. This improves female literacy rates and increases female participation in the workforce, reducing female foeticide rates in underdeveloped countries.

Implementing gender education within schools and the workplace will add to gender neutrality within society, increasing the value of women. Sympathizing with women's suffrage in countries limiting women's rights will add to the battle in which women fight for freedoms in their home state. Building upon gender equality in education and teaching women strategies to cope with their situations will help them grow confidence and want to spread their knowledge and passions with their female children. The issue with female infanticide is that women devalue their own gender. When mothers give away their female children, it only adds to the lesser image of women. Having women respect themselves and their own children for who they are will increase the population, and it will increase the value of women. It may take a long time to implement these changes in society, but societal revision is a slow process. Education, value in life, and passion for gender are all aspects of decreasing female infanticide. Having locations to rid of a female child, such as "The Girl Child Protection Scheme", appears as a step toward change. This program only adds to the availability and opportunity for female infanticide. Instrumentalizing gender education and value of life will greatly inspire change in societies that participate in such process of termination.

Consequences and reactions

As a result of large high female infanticide rates in countries, the population is often skewed with a larger proportion of males. According to the United Nations, this surplus of men in society coincides with increasing rates of child abuse, domestic violence, and bride trafficking/kidnapping, presenting a grave threat to the security of women in the affected areas. This also increases the likelihood of women becoming victims of harmful sexually transmitted diseases, which further adversely affects their lives as well as population rates. Owing to these concerning issues, there is also a concerning boost in maternal mortality rates and an increase in mental health conditions among women in these locations.

The Geneva Centre for the Democratic Control of Armed Forces (DCAF) wrote in their 2005 report, Women in an Insecure World, that at a time when the number of casualties in war had fallen, a "secret genocide" was being carried out against women. According to DCAF the demographic shortfall of women who have died for gender related issues is in the same range as the 191 million estimated dead from all conflicts in the twentieth century. In 2012, the documentary It's a Girl: The Three Deadliest Words in the World was released, and in one interview, an Indian woman claimed she had killed eight of her daughters.

Globular cluster

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