Recent Advances for Global Perspectives on Etiology, Pathophysiology, Clinical Presentations, and Management of Moyamoya Disease

Moyamoya disease (MMD) is a condition characterized by the gradual narrowing and blockage of blood vessels in the brain, specifically those in the circle of Willis and the arteries that supply it. This results in reduced blood flow and oxygen to the brain, leading to progressive symptoms and potential complications. The underlying pathophysiological mechanism remains elucidated. However, recent studies have highlighted numerous etiologic factors: abnormal immune complex responses, susceptibility genes, branched-chain amino acids, antibodies, heritable diseases, and acquired diseases, which may be the great potential triggers for the development of moyamoya disease. Its clinical presentation has varying degrees from transient asymptomatic events to significant neurological deficits. Moyamoya disease (MMD) shows different patterns in children and adults. Children with MMD are more susceptible to ischemic events due to decreased blood flow to the brain. Conversely, adults with MMD are more prone to hemorrhagic events involving brain bleeding. Children with MMD may experience a range of symptoms including motor impairments, sensory issues, seizures, headaches, dizziness, cognitive delays, or ongoing neurological problems. Although adults may present with similar clinical symptoms as children, they are more prone to experiencing sudden onset intraventricular, subarachnoid, or intracerebral hemorrhages. One of the challenges in moyamoya disease is the potential for misdiagnosis or delayed diagnosis, particularly when physicians fail to consider MMD as a possible cause in stroke patients. This review aims to provide a comprehensive overview of recent global studies on the pathophysiology of MMD, along with advancements in its management. Additionally, the review will delve into various surgical treatment options for MMD, as well as its rare occurrence alongside atrioventricular malformations. Exciting prospects include the use of autologous bone marrow transplant and the potential role of Connexin 43 protein treatment in the development of moyamoya disease.

Changes in the etiology of liver cirrhosis and the corresponding management strategies

We read with interest the article by Xing Wang,which was published in the recent issue of the World Journal of Hepatology 2023;15:1294-1306.This article focuses particularly on the prevalence and trends in the etiology of liver cirrhosis(LC),prognosis for patients suffering from cirrhosis-related complications and hepatocellular carcinoma(HCC),and management strategies.The etiology of cirrhosis varies according to geographical,economic,and population factors.Viral hepatitis is the dominant cause in China.Vaccination and effective treatment have reduced the number of people with viral hepatitis,but the overall number is still large.Patients with viral hepatitis who progress over time to LC and HCC remain an important population to manage.The increased incidence of metabolic syndrome and alcohol consumption is likely to lead to a potential exponential increase in metabolic dysfunction-associated steatotic liver disease(MASLD)-associated LC and alcoholic liver disease in the future.Investigating the evolution of the etiology of LC is important for guiding the direction of future research and policy development.These changing trends indicate a need for greater emphasis on tackling obesity and diabetes,and implementing more effective measures to regulate alcohol consumption in order to reduce the occurrence of MASLD.In an effort to help cope with these changing trends,the authors further proposed countermeasures for healthcare authorities doctors,and patients.

Etiology and pathogenesis of corona virus disease 2019 on the view of Chinese medicine

Traditional Chinese Medicine has played an important role in the prevention and treatment of the Corona Virus Disease 2019 epidemic.But in views of different TCM scholars there are different opinions about disease name,characteristic of etiology,law of pathogenesis about this epidemic.Based on related literatures,this article overviews of the characteristics of TCM etiology,law of pathogenesis and methods of syndrome differentiation,hoping to find research method that fit in with TCM clinical practice.Prerequisite of treatment is identifying the cause.The clinical manifestations of patients are important to TCM,and the etiological attributes can be inferred from the clinical manifestations.SARS-CoV-2 belongs to exogenous etiological factors,but there are different opinions about its characteristics of six pathogenic factors.Cold,Dampness,Warm,Dry,Toxin,Summer-heat,Wind,are all involved.Thus,different understanding of the pathogenesis and the law of transmission is caused.Such as cold and dampness hurt Yang,furthermore,consumed of Qi;dampness and toxin infected from external environment,turbid dampness produced inside the body;dryness affecting lungs and consume of Yin;warm-heat-turbid-toxin affected lungs,stomach and intestine;and then produced phlegm stagnation or blood stasis,furthermore consumed Qi and Yin.Based on those differences,methods of syndrome differentiation in treatment of COVID-19 are diverse,which contain pattern differentiation of zang-fu organs,pattern differentiation of Wei-defence,Qi,Ying nutrients and blood;pattern differentiation by the eight principles,and pattern differentiation of six meridians.Because of SARS-CoV-2 can spread to the whole country or even the whole world in a short period of time,its pathogenic nature should be roughly the same.So studying the treatment of COVID-19 based on clinical cases,refining the similarities and differences in the clinical presentation of patients with different subtypes during the epidemic,clarification of the etiologic attribution and evolutionary patterns of disease mechanisms,developing a comprehensive understanding of COVID-19 in Chinese medicine is needed.Furthermore,getting a full understanding of COVID-19,and providing reference for the prevention and treatment of unknown infectious diseases.

Genetic regulation of cell type-specific chromatin accessibility shapes brain disease etiology

Nucleotide variants in cell type-specific gene regulatory elements in the human brain are risk factors for human disease.We measured chromatin accessibility in 1932 aliquots of sorted neurons and non-neurons from 616 human postmortem brains and identified 34,539 open chromatin regions with chromatin accessibility quantitative trait loci(caQTLs).Only 10.4%of caQTLs are shared between neurons and non-neurons,which supports cell type-specific genetic regulation of the brain regulome.Incorporating allele-specific chromatin accessibility improves statistical fine-mapping and refines molecular mechanisms that underlie disease risk.Using massively parallel reporter assays in induced excitatory neurons,we screened 19,893 brain QTLs and identified the functional impact of 476 regulatory variants.Combined,this comprehensive resource captures variation in the human brain regulome and provides insights into disease etiology.

Analysis of Etiology,Diagnosis,and Treatment Strategy and Efficacy of Pulsatile Tinnitus Caused by Abnormal Vascular Anatomy

Objective To investigate the etiology,clinical characteristics,diagnosis,and treatment strategies and efficacy of pulsatile tinnitus(PT)caused by vascular anatomy abnormality.Methods The clinical data of 45 patients with PT in our hospital from 2012 to 2019 were collected and retrospectively analyzed.Results All 45 patients had vascular anatomical abnormalities.The patients were divided into 10 categories according to the different locations of vascular abnormalities:sigmoid sinus diverticulum(SSD),sigmoid sinus wall dehiscence(SSWD),SSWD with high jugular bulb,pure dilated mastoid emissary vein,aberrant internal carotid artery(ICA)in the middle ear,transverse-sigmoid sinus(TSS)transition stenosis,TSS transition stenosis with SSD,persistent occipital sinus stenosis,petrous segment stenosis of ICA,and dural arteriovenous fistula.All patients complained of PT synchronous with heartbeat rhythm.Endovascular interventional therapy and extravascular open surgery were used according to the location of the vascular lesions.Tinnitus disappeared in 41 patients,was significantly relieved in 3 patients,and was unchanged in 1 patient postoperatively.Except for one patient with transient headache postoperatively,no obvious complications occurred.Conclusion PT caused by vascular anatomy abnormalities can be identified by detailed medical history and physical and imaging examination.PT can be relieved or even completely alleviated after appropriate surgical treatments.

Etiology analysis for term newborns with severe hyperbilirubinemia in eastern Guangdong of China

BACKGROUND Neonatal hyperbilirubinemia is one of the common diseases of newborns that typically presents with yellow staining of skin,resulting in sequelaes such as hearing loss,motor and intellectual development disorders,and even death.The pathogenic factors of neonatal hyperbilirubinemia are complex.Different cases of hyperbilirubinemia may have a single or mixed etiology.AIM To explore the etiological characteristics of severe hyperbilirubinemia in term newborns of eastern Guangdong of China.METHODS Term newborns with severe hyperbilirubinemia in one hospital from January 2012 to December 2021 were retrospectively analyzed.The etiology was determined according to the laboratory results and clinical manifestations.RESULTS Among 1602 term newborns with hyperbilirubinemia in eastern Guangdong of China,32.20%(580/1602)was severe hyperbilirubinemia.Among the causes of severe hyperbilirubinemia,neonatal hemolysis accounted for 15.17%,breast milk jaundice accounted for 12.09%,infection accounted for 10.17%,glucose-6-phosphate dehydrogenase(G6PD)deficiency accounted for 9.14%,and the coexistence of multiple etiologies accounted for 6.55%,unknown etiology accounted for 41.72%.ABO hemolysis and G6PD deficiency were the most common causes in the 20 cases with bilirubin encephalopathy.94 severe hyperbilirubinemia newborns were tested for uridine diphosphate glucuronosyl transferase 1A1(UGT1A1)*6 variant(rs4148323,c.211G>A,p.Arg71Gly),9 cases were 211 G to A homozygous variant,37 cases were 211 G to A heterozygous variant,and 48 cases were wild genotypes.CONCLUSION The main cause for severe hyperbilirubinemia and bilirubin encephalopathy in eastern Guangdong of China were the hemolytic disease of the newborns,G6PD deficiency and infection.UGT1A1 gene variant was also a high-risk factor for neonatal hyperbilirubinemia.Targeted prevention and treatment according to the etiology may reduce the occurrence of bilirubin encephalopathy and kernicterus.

Acute cholangitis: Does malignant biliary obstruction vs choledocholithiasis etiology change the clinical presentation and outcomes?

BACKGROUND Whether clinical outcomes of acute cholangitis(AC)vary by etiology is unclear.AIM To compare outcomes in AC caused by malignant biliary obstruction(MBO)and common bile duct stones(CBDS).METHODS This retrospective study included 516 patients undergoing endoscopic retrograde cholangiopancreatography(ERCP)due to AC caused by MBO(MBO group,n=56)and CBDS(CBDS group,n=460).Clinical and laboratory parameters were compared between the groups.Propensity score matching(PSM)created 55 matched pairs.Confounders used in the PSM analysis were age,sex,time to ERCP,and technical success of ERCP.The primary outcome comparison was 30-d mortality.The secondary outcome comparisons were intensive care unit(ICU)admission rate,length of hospital stay(LOHS),and 30-d readmission rate.RESULTS Compared with the CBDS group,the MBO group had significantly lower body temperature,percentage of abnormal white blood cell counts,and serum levels of aspartate aminotransferase,alanine aminotransferase,and creatinine.Body temperature,percent abnormal white blood cell count,and serum aspartate aminotransferase levels remained significantly lower in the MBO group in the PSM analysis.Platelet count,prothrombin time/international normalized ratio,and serum levels of alkaline phosphatase and total bilirubin were significantly higher in the MBO group.The MBO group had a significantly higher percentage of severe AC(33.9%vs 22.0%,P=0.045)and received ERCP later(median,92.5 h vs 47.4 h,P<0.001).However,the two differences were not found in the PSM analysis.The 30-d mortality(5.4%vs 0.7%,P=0.019),ICU admission rates(12.5%vs 4.8%,P=0.028),30-d readmission rates(23.2%vs 8.0%,P<0.001),and LOHS(median,16.5 d vs 7.0 d,P<0.001)were significantly higher or longer in the MBO group.However,only LOHS remained significant in the PSM analysis.Multivariate analysis revealed that time to ERCP and multiple organ dysfunction were independent factors associated with 30-d mortality.CONCLUSION MBO patients underwent ERCP later and thus had a worse prognosis than CBDS patients.Therefore,clinicians should remain vigilant in MBO patients with clinically suspected AC,and perform ERCP for biliary drainage as soon as possible.

Age-related outcomes in patients with cardiogenic shock stratified by etiology

BACKGROUND As a result of improved and novel treatment strategies,the spectrum of patients with cardiovascular disease is consistently changing.Overall,those patients are typically older and characterized by increased burden with comorbidities.Limited data on the prognostic impact of age in cardiogenic shock(CS)is available.Therefore,this study investigates the prognostic impact of age in patients with CS.METHODS From 2019 to 2021,consecutive patients with CS of any cause were included.The prognostic value of age(i.e.,60-80 years and>80 years)was investigated for 30-day all-cause mortality.Spearman’s correlations,Kaplan-Meier analyses,as well as multivariable Cox proportional regression analyses were performed for statistics.Subsequent risk assessment was performed based on the presence or absence of CS related to acute myocardial infarction(AMI).RESULTS 223 CS patients were included with a median age of 77 years(interquartile range:69-82 years).No significant difference in 30-day all-cause mortality was observed for both age-groups(54.6%vs.63.4%,log-rank P=0.169;HR=1.273,95%CI:0.886-1.831,P=0.192).In contrast,when analyzing subgroups stratified by CS-etiology,AMI-related CS patients of the group>80 years showed an increased risk of 30-day all-cause mortality(78.1%vs.60.0%,log-rank P=0.032;HR=1.635,95%CI:1.000-2.673,P=0.050),which was still evident after multivariable adjustment(HR=2.072,95%CI:1.174-3.656,P=0.012).CONCLUSIONS Age was not associated with 30-day all-cause mortality in patients with CS of mixed etiology.However,increasing age was shown to be a significant predictor of increased mortality-risk in the subgroup of patients presenting with AMI-CS.

Etiology, Prevalence, and Management of Oral and Maxillofacial Soft Tissue Injuries in Children at the Komfo Anokye Teaching Hospital, Kumasi-Ghana

Background: Maxillofacial injury may vary from simple soft tissue lacerations to complex fractures of the orofacial region. Soft tissue injuries, whether isolated or in combination with other injuries, form part of the frequent traumatic craniofacial injuries seen at the emergency department. The force of impact and the injury type is directly related to the severity of the injury sustained. This study aimed to analyze the etiological factors, prevalence, and management of oral and maxillofacial soft tissue injuries at the Komfo Anokye Teaching Hospital. Methods: This was a prospective study that involved children presenting with oral and maxillofacial injuries at the Accident and Emergency Department and the Oral and Maxillofacial Surgery unit of the Komfo Anokye Teaching Hospital in Kumasi between the period of April to October 2020 (6 months). Patient selection was by convenience sampling targeting all children with injuries who met the inclusion criteria. Inclusion criteria were children below the age of 18 years whose parents or caregivers consent to participation. Children with maxillofacial injuries as a result of burns were excluded from the study. Results: During the study period a total of 134 children were reviewed with oral and maxillofacial injuries at KATH. Of these, 107 (78.9%) were recorded cases of orofacial soft tissue injuries. There were 63 (58.9%) males and 44 (41.1%) females and the male-to-female ratio was 1.5:1. The age range of patients studied was 8 months – 17 years, with mean age ± SD being 9.5 ± 5.3 years. Road Traffic Crash (50.5%) was the most common etiology of which Motor cycle crash constituted 24.3% and Pedestrian knockdown was 19.6%. Falls (42.1%) were the next most common etiology. The lips (19.8%) and the forehead (18.5%) were the most frequently injured sites on the face whiles the tongue (3.3%) had the most injuries intraorally. Laceration (45.7%) was the most frequent injury reviewed, followed by abrasions (35.8%). Most of the soft tissue injuries underwent primary closure (56.3%). A complication rate of 21.2% was recorded in this study and hypertrophic scarring (11.3%) was the most observed.

Epidemiology and etiology of chemical ocular injury:A brief review

Chemical ocular injury is one of the common ophthalmologic emergencies that can cause vision loss and serious complications.Despite all protective measures,it continues to be a serious public health problem,especially in young male patients.Although it is known that injuries occur most frequently in the workplace and in young male patients,there is a variable frequency and distribution in different regions around the world.In addition,with the coronavirus disease 2019 pandemic,there are changing trends in ocular chemical injuries.This review aims to specify an update on the epidemiological and etiological features of ocular chemical injuries.

Acute hepatitis of unknown etiology in an adult female:A case report

BACKGROUND Acute liver injury(ALI)refers to inflammation of the hepatic parenchyma without hepatic encephalopathy that lasts less than 6 mo.When the etiology is unknown,Acute Hepatitis of Unknown Origin(AHUO)can present as a diagnostic and treatment challenge.AHUO in the adult population is unusual and poorly documented.It has an incidence between 11%and 75%.Currently,no treatment guidelines exist.With no identified cause,treatment is often blind,and the wrong treatment plan may have unintended consequences.CASE SUMMARY We present the case of a 58-year-old woman who presented to the emergency room for elevated liver function tests(LFTs).Her symptoms started 10 d prior to admission and included nausea,vomiting,jaundice,decreased appetite,weight loss of 10 lbs,and dark urine.She denied drinking alcohol or taking any hepatotoxic agents,including acetaminophen,statins,vitamins,or supplements.She was admitted to the hospital,and an etiologic work-up was carried out.Her initial bloodwork revealed elevated liver enzymes(alanine aminotransferase 2500 U/L,aspartate aminotransferase 3159 U/L,and alkaline phosphatase 714 U/L)and elevated total bilirubin of 6.4 mg/dL.She tested negative for common infectious etiologies such as hepatotropic viruses A,B,C,and E.Further infective work-up revealed negative serology for cytomegalovirus,Epstein-Barr virus,herpes simplex virus 1&2,and human immunodeficiency virus.Her autoanti-body test results were negative,including anti-smooth muscle antibody,anti-mitochondrial antibody,and anti-liver kidney microsome 1 antibody.Magnetic resonance cholangiopancreatography ruled out biliary causes of elevated LFTs,and her core liver biopsy proved inconclusive.Over the course of her hospital stay,the patient's LFTs improved with supportive care and without steroids.CONCLUSION Idiopathic hepatitis makes treatment challenging.It can leave patients feeling confused and unfulfilled.Thus,educating the patient thoroughly for shared decision-making and management becomes essential.

Advances of Genetic Testing Technology in Etiology Diagnosis of Recurrent Spontaneous Abortion

Recurrent spontaneous abortion (RSA) is a complex and heterogeneous disorder with multiple etiologies. Genetic factors are thought to play an important role in the etiology of RSA. With recent advances in genetic testing technologies, there has been an increasing interest in using these tools to diagnose the etiology of RSA. This review discusses the different types of genetic testing methods, such as karyotyping, chromosomal microarray analysis, next-generation sequencing, and their applications in the diagnosis of the etiology RSA. The use of genetic testing in the diagnosis of RSA has the potential to improve the accuracy of diagnosis and the understanding of the underlying mechanisms of the disorder, which could lead to better management and treatment of affected individuals.

Male and Female Hypogonadisms: Etiological, Metabolic and Osteodensitometric Aspects

Introduction: Studies showed a high prevalence of metabolic abnormalities including dyslipidemia, type 2 diabetes in cases of low testosterone in men and which are associated with increased cardiovascular risk. Hypogonadism represents the second cause of endocrine osteoporosis. Objectives: The objectives of our work were: to determine the main causes of hypogonadism in women and men;to assess the frequency of metabolic and osteosdensitometric abnormalities in the hypogonadal population. Patients and methods: A retrospective descriptive study was carried out over 7 years on 120 patients, hospitalized in the Endocrinology department of the Hassan II University Hospital of Fez-Morocco for hypogonadism. The patients selected were those who had symptoms of hypogonadism confirmed in men by: low total testosterone for Tanner stage in adolescents, ng/ml or lower limit of normal for adults;in women, hypoestrogenia 30 pg/l. Gonadotropin dosage, karyotype, pelvic or testicular ultrasound and pituitary MRI, for etiological diagnosis, were performed. Bone densitometry was performed for bone impact and lipid profile for metabolic profile. Results: Out of 120 patients, there were 77 women and 43 men. The average age was 31.51 years. In men, the main causes were central hypogonadism in 67.4% and primary testicular failure in 32.6%. In women, central hypogonadism was also the most common cause noted in 63.7% and premature ovarian failure was observed in 36.4%. HypoHDL was significantly more frequent p (0.005) in women, osteopenia and osteoporosis were significantly more frequent in women than in men p (0.046). Conclusion: Central causes represent the most common etiology of hypogonadism in both sexes;abnormalities of bone mineralization and metabolic disorders were predominant in women.

Eyelid Wounds: Epidemiological, Clinical and Etiological Aspects

Purpose: The aim is to show epidemiological, clinical and etiological characteristics of palpebral wounds. Methodology: This was a retrospective study focusing on patients with an eyelid wound, over a 10-year period from 2012 to 2021. We collected and analyzed the data using Excel. Results: The frequency of eyelid wounds was 0.1%. The average age of our patients was 19.38 years with a range of 1 and 62 years. The sex ratio was 3.7. Eighty-one percent of patients lived in Dakar. Fifty-seven percent (57%) of patients consulted less than 24 hours after the trauma and 7% of patients on D1. The circumstances were brawls (11%), domestic accidents (9%), road accidents (6%), and work accidents (6%). We noted 1 case of dog bite. Thirteen patients presented with post-traumatic decreased visual acuity. Involvement of the isolated upper eyelid was noted in 40% of cases and both eyelids in 15% of cases. Involvement of the lacrimal ducts was noted in 17% of cases, and that of the free edge in 21% of cases. Eyelid wounds were associated with eyeball damage in 21% of cases. Various associated lesions were observed. Ninety-one percent of patients received surgical treatment. Three cases of superinfections, 1 case of conjunctival granuloma and 1 case of phthysis of the eyeball with postoperative retinal detachment were noted. Conclusion: Eyelid sores are relatively common in our context. They require rapid surgical treatment in order to preserve the functional and aesthetic prognosis. .

Secondary diabetes due to different etiologies:A problem worthy of attention

There are many factors in the occurrence of diabetes,which can result in insufficient insulin secretion and insulin receptor resistance.Including pituitary tumors,can also lead to the occurrence of diabetes,if the primary disease can not be well controlled in time,such secondary diabetes control is more difficult.In the process of clinical diagnosis and treatment,these factors need to be taken into account,timely detection and treatment of primary diseases,so as to reduce the possibility of clinical missed diagnosis.

Etiological Analysis of 248 Cases of Oculomotor Nerve Palsy

Objective:To explore the main causes of oculomotor nerve palsy,providing a reference for clinical diagnosis and treatment.Methods:A total of 248 patients with oculomotor nerve palsy treated in the hospital from January 2016 to January 2018 were selected,and their causes and treatments were summarized.Results:This study found that the main causes of oculomotor nerve palsy were intracranial aneurysms,brain stem lesions,and brain inflammation.A few cases were due to viral infections and congenital oculomotor nerve palsy,while some patients had unknown causes.After treatment in our hospital,most patients experienced relief,although 12 patients died.Conclusion:The etiology of oculomotor nerve palsy is complex,and choosing appropriate drugs during treatment is challenging.Timely identification of the cause is an effective method for treatment.

Liver fibrosis and hepatic stellate cells: Etiology, pathological hallmarks and therapeutic targets

Liver fibrosis is a reversible wound-healing process aimed at maintaining organ integrity, and presents as the critical pre-stage of liver cirrhosis, which will eventually progress to hepatocellular carcinoma in the absence of liver transplantation. Fibrosis generally results from chronic hepatic injury caused by various factors, mainly viral infection, schistosomiasis, and alcoholism; however, the exact pathological mechanisms are still unknown. Although numerous drugs have been shown to have antifibrotic activity in vitro and in animal models, none of these drugs have been shown to be efficacious in the clinic. Importantly, hepatic stellate cells(HSCs) play a key role in the initiation, progression, and regression of liver fibrosis by secreting fibrogenic factors that encourage portal fibrocytes, fibroblasts, and bone marrow-derived myofibroblasts to produce collagen and thereby propagate fibrosis. These cells are subject to intricate cross-talk with adjacent cells, resulting in scarring and subsequent liver damage. Thus, an understanding of the molecular mechanisms of liver fibrosis and their relationships with HSCs is essential for the discovery of new therapeutic targets. This comprehensive review outlines the role of HSCs in liver fibrosis and details novel strategies to suppress HSC activity, thereby providing new insights into potential treatments for liver fibrosis.

Epidemiology,etiology,and prevention of esophageal squamous cell carcinoma in China

Esophageal cancer is one of the most fatal diseases worldwide mainly because of its rapid progression and poor prognosis.Although the incidence of esophageal adenocarcinoma has markedly risen in North America and Europe in the past several decades, esophageal squamous cell carcinoma is still the predominant subtype of esophageal cancer, especially in China. It accounts for more than 90% of all esophageal squamous cell carcinoma cases in China. Geographical differentiation is one of the most distinctive characteristics of esophageal cancer. The progression, risk factors, and prognosis of these two subtypes of esophageal cancer differ. This study reviews the epidemiology, etiology, and prevention of esophageal squamous cell carcinoma in China, thereby providing systematic references for policy-makers who will decide on issues of esophageal cancer prevention and control.

Progress of gastric cancer etiology:N-nitrosamides in the 1990s

Stomach carcinoma is still the leading cause of cancer death in China and the second one in the world. Its possible causes include: A) chemical factors such as intragastric formation of N-nitroso compounds (NOC) and high salt intake; B ) biological factors such as infection of Helicobacter pylori and biotoxins intake; and C ) nutritional factors such as deficiency of vitamin C, selenium, and other antioxidants. Nitrogenous precursors of NOC, e.g., alkylamines, alkylureas, alkylguanidines, and alkylamides, occur widely in nature and potential nitrosating agents, e.g., nitrite (NO2-) and NOx (the gaseous oxides of nitrogen ) are similarly widespread. Relationship between exposure to NOC and causes of human cancer was investigated extensively ten years ago. Results indicated that the exposures of NOC might contribute to the occurrences of malignancy in the upper digestive tracts including stomachs. It was also observed that both high salt intake and deficiency of some micronutrients enhanced NOC-induced carcinogenicity. Recent studies show that infection of H. pylori can lead to atrophic gastritis and achlorhydria, and promote endogenous formation of NOC indirectly[1] . Much attention has been paid to stomach cancer and NOC regarding the characterization of natural N-nitrosamides in human environment in the 1990s.

Study on environmental etiology of high incidence areas of liver cancer in China

INTRODUCTIONChina is a country with a high incidence of liver cancer insome areas.Liver cancer has a wide distribution andthreatens human health seriously.A rough estimationshows that out of a population of 1.2×10~8 in liver