RESUMO
Haiti has the highest human rabies burden in the Western Hemisphere. There is no published literature describing the public's perceptions of rabies in Haiti, information that is critical to developing effective interventions and government policies. We conducted a knowledge, attitudes and practices survey of 550 community members and 116 health professionals in Pétionville, Haiti in 2013 to understand the perception of rabies in these populations. The majority of respondents (85%) knew that dogs were the primary reservoir for rabies, yet only 1% were aware that bats and mongooses could transmit rabies. Animal bites were recognized as a mechanism of rabies transmission by 77% of the population and 76% were aware that the disease could be prevented by vaccination. Of 172 persons reporting a bite, only 37% sought medical treatment. The annual bite incidence rate in respondents was 0·9%. Only 31% of bite victims reported that they started the rabies vaccination series. Only 38% of respondents reported that their dog had been vaccinated against rabies. The majority of medical professionals recognized that dogs were the main reservoir for rabies (98%), but only 28% reported bats and 14% reported mongooses as posing a risk for rabies infection. Bites were reported as a mechanism of rabies transmission by 73% of respondents; exposure to saliva was reported by 20%. Thirty-four percent of medical professionals reported they would wash a bite wound with soap and water and 2·8% specifically mentioned rabies vaccination as a component of post-bite treatment. The majority of healthcare professionals recommended some form of rabies assessment for biting animals; 68·9% recommended a 14-day observation period, 60·4% recommended a veterinary consultation, and 13·2% recommended checking the vaccination status of the animal. Fewer than 15% of healthcare professionals had ever received training on rabies prevention and 77% did not know where to go to procure rabies vaccine for bite victims. Both study populations had a high level of knowledge about the primary reservoir for rabies and the mode of transmission. However, there is a need to improve the level of knowledge regarding the importance of seeking medical care for dog bites and additional training on rabies prevention for healthcare professionals. Distribution channels for rabies vaccines should be evaluated, as the majority of healthcare providers did not know where rabies vaccines could be obtained. Canine rabies vaccination is the primary intervention for rabies control programmes, yet most owned dogs in this population were not vaccinated.
Assuntos
Competência Clínica , Comportamentos Relacionados com a Saúde , Conhecimentos, Atitudes e Prática em Saúde , Pessoal de Saúde/psicologia , Raiva/psicologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Haiti , Acessibilidade aos Serviços de Saúde/estatística & dados numéricos , Humanos , Masculino , Pessoa de Meia-Idade , Risco , Adulto JovemRESUMO
El trauma renal se presenta en el 10 por ciento de los pacientes traumatizados y se clasifica en abierto o cerrado de acuerdo a su mecanismo. El trauma renal abierto alcanza en zonas urbanas entre un 15-20 por ciento del total de traumas renales. Es producido principalmente por armas blancas o de fuego; estas últimas son de alta energía y se asocian a /lesiones de otros órganos. Se presenta nuestra experiencia en traumatismo renal abierto en los últimos 18 meses. Se evaluaron un total de 196 pacientes con traumatismo torácico, abdominal y toracoabdominal ingresados entre Julio de 2009 y Diciembre de 2010. Se identificaron 9 pacientes con diagnóstico de trauma renal abierta con confirmación diagnóstica por imágenes o durante el intraoperatorio. Las edades oscilan entre 16 y 30 años con un promedio de 22,7; 8 de 9 son de sexo masculino. El mecanismo de trauma es en un 55,5 por ciento (5/9) por arma de fuego y en un 44,5 por ciento (4/9) por arma blanca. Se clasificó el trauma renal según American Association for the Surgery of Trauma. Encontrándose que 2/9 (22 por ciento) corresponden a grado ll, 3/9 (33 por ciento) a grado a grado ll,3/9 (33 por ciento) a grado IV y 1/9 (11 por ciento) a grado V. La baja de hematocrito varió entre 1 y 23 por ciento, con un promedio de 11,3 por ciento. Se decidió manejo conservador en 5/9 pacientes: dentro de esto no se consideran las cirugías efectuadas por lesión de órgano no urológico. Un total de 3 pacientes (33,3 por ciento) requirió nefrectomía. Lesiones toracoabdominales asociadas se observaron en 7 de 9 pacientes, siendo las más frecuentes el Bazo (2), Hígado (2), Estómago (2), Diafragma (2) y Colon (2). No hubo muertes en el grupo de estudio en seguimiento de 6 /meses. A pesar de la baja incidencia de trauma renal abierto, se observa un gran número de pacientes considerando otras series nacionales. La anterior, probablemente debido a las características socioculturales del centro hospitalario...
Renal trauma is present in 10 percent of politraumatized patients. Its classified into opened or closed renal trauma, according to its mechanism. Opened renal trauma in urban areas reaches 15ta 20 percent of all renal traumas. Its mainly secondary to gunshot wounds or knifes. Gunshot wounds are classified as hi energy trauma and usually are associated to other organ lesions. We present our experience in opened renal trauma in the last 18 months. Retrospective study where 196 patients with thoracic, abdominal and thoraco-abdominal trauma admitted in the emergency room between July 2009 and December 201 0. Nine patients were identified with opened renal trauma, with diagnostic confirmation y imaging study o during surgery. The ages ranged between 16 and 30 years; with an average of 22, 7 years. Eight out of nine patients were males. The mechanism of injury was in 55.5 percent (5/9) produced by gunshot and 44.5 percent (4/9) by knife. The opened renal traumas were classified according to the American Association for the Surgery of Trauma. We found that 2/9 (22 percent) belonged to grade ll. 3/9 (33 percent) to grade lll. 3/9 (33 percent) to grade IV and 1/9 to grade V (11 percent). The drop in hematocrit ranged between 1percent and 23percent, with an average of 11.3 percent. Five out of nine patients were treated conservatively, excluding surgeries because of neurologic¡ organs. Three patients required nephrectomy. Seven out of nine patients presented association with thoraco-abdominat injuries. The most frequent were spleen (2), liver (2), stomach (2), and diaphragm (2), and colon (2). There was no mortality during a six months follow-up. Despite the low incidence of opened renal trauma, we present a large number of patients according to other national reports, probably due to socio-cultural environment of this hospital...
Assuntos
Humanos , Masculino , Feminino , Adolescente , Adulto , Adulto Jovem , Ferimentos e Lesões/complicações , Ferimentos e Lesões/epidemiologia , Rim/lesões , Estudos Retrospectivos , Ferimentos e Lesões/classificação , Ferimentos e Lesões/terapia , Serviço Hospitalar de Emergência , Tempo de InternaçãoRESUMO
Con el objeto de mejorar el manejo de pacientes con colelitiasis y coledocolitiasis, en los cuales la conducta más usada es la colangiografía endoscópica (CE) previa a la colecistectomía laparoscópica, se presenta un protocolo de tratamiento llevado a cabo en el Hospital de Carabineros de Chile en que se realiza colecistectomía laparoscópica y CE en un mismo tiempo anestésico, efectuado por un equipo de cirujanos laparo-endoscopistas. Para esto se utiliza la técnica de "Rendezvous" modificada, realizando primero la colecistectomía y luego la CE. Resultados: Se presenta los primeros 18 pacientes con alta sospecha de coledocolitiasis, de los cuales sólo en 14 se objetivó la presencia de cálculos por colangiografía intraoperatoria realizando la técnica "rendezvous" en 13 de ellos. Se logró un 100 por ciento de éxito, sin complicaciones y con tiempos quirúrgicos y de estadía postoperatorio muy adecuados.
Background: The usual management of patients with cholelithiasis in whom a choledocholithiasis is suspected, is to perform en endoscopio cholangiography prior to laparoscopic cholecystectomy. However a new approach is to perform both procedures simultaneously using a rendezvous technique, to reduce complications and improve the rate of successful bile duct cannulation. Aim: To report the experience with simultaneous endoscopio cholangiography and laparoscopic cholecystectomy. Material and Methods: Eighteen patients with cholelithiasis and a high suspicion of choledocholithiasis were considered eligible for the study. The technique was modified, performing first the cholecystectomy and afterwards the endoscopio cholangiography. Results: In four patients, the intraoperative cholangiography did not show the presence of choledocholithiasis. In the rest, the presence of choledocholithiasis was confirmed and 13 were subjected to the rendezvous technique, that was successful in all. Conclusions: Simultaneous endoscopio cholangiography during laparoscopic cholecystectomy is feasible and safe.
Assuntos
Humanos , Colecistectomia Laparoscópica , Colangiografia/métodos , Coledocolitíase/cirurgia , Endoscopia , Protocolos Clínicos , Terapia Combinada , Colelitíase/cirurgia , Fatores de Tempo , Resultado do TratamentoRESUMO
Aunque el tratamiento con agentes fleboesclerosantes constituye una alternativa para las várices, éste no está exento de complicaciones, las que pueden ser de tipo general y local. De estas últimas, la inyección intraarterial accidental es la más temida y devastadora, ya que puede llevar a la pérdida de la extremidad. Presentamos un caso clínico de esta complicación que fue tratado en forma algo tardía con un resultado aceptable, a través de una infusión sistémica con estreptoquinasa. Se concluye que si bien este tratamiento es una buena alternativa para tratar las várices, éste debe ser restringido a casos muy seleccionados, evitando los sitios de riesgo de punción arterial y hecho por profesionales entrenados en la materia
Assuntos
Humanos , Masculino , Adulto , Etanolamina/efeitos adversos , Injeções Intra-Arteriais/efeitos adversos , Síndrome Pós-Flebítica/tratamento farmacológico , Amputação Cirúrgica , Etanolamina/administração & dosagem , Etanolamina/farmacologia , Pé , Síndrome Pós-Flebítica/complicações , Síndrome Pós-Flebítica/diagnóstico , Estreptoquinase/administração & dosagem , Estreptoquinase/farmacologia , Transplante de PeleRESUMO
Los aneurismas de las arterias carótidas extracraneales son lesiones muy poco frecuentes. En Chile sólo se han reportado cinco casos: dos ateroescleróticos, dos congénitos y uno secundario a extirpación de tumor del cuerpo carotídeo. Aunque obedecen a diferentes causas, aquellos secundarios a endarterectomía carotídea son bastante infrecuentes, reportándose una incidencia de 0,30 por ciento en la literatura mundial, por lo que el objetivo de esta presentación es reportar un caso clínico de esta patología. Se presenta un caso de aneurisma postendarterectomía carotídea, de aparición tardía, que, aparte de presentar un aumento de volumen pulsátil en la región cervical, refiere varios episodios transitorios de isquemia cerebral. Su diagnóstico fue hecho en base a eco Doppler y angiografía, siendo operada con shunt para mantener la circulación cerebral, efectuándose una reparación de la arteria con parche de vena safena. Se concluye que el tratamiento de esta patología radica en un minucioso estudio preoperatorio, y en cuanto a su tratamiento es importante la utilización de shunt intraoperatorio, donde la reparación debe ser simple y efectiva a fin de prevenir nuevos episodios de isquemia cerebral
Assuntos
Humanos , Feminino , Idoso , Aneurisma/etiologia , Endarterectomia das Carótidas/efeitos adversos , Isquemia Encefálica/prevenção & controle , Angiografia Cerebral/estatística & dados numéricos , Ecocardiografia Doppler/estatística & dados numéricosRESUMO
El objetivo del presente trabajo fue evaluar la existencia de hipoesplenismo funcional en enfermedades autoinmunes. La hipofunción esplénica se determinó por la presencia de cuerpos de Howell-Jolly en eritrocitos de la sangre y posterior centellografía esplénica con radiocoloides marcados con 99Tc, en pacientes en los que se habían descartado otras posibles causas de cuerpo de Howell-Jolly. Se estudiaron extendidos de sangre periférica de 174 pacientes con enfermedades autoinmunes y de 32 otras enfermedades de patogenia inmunológica y 63 indivíduos normales. Se encontró evidencia de hipoesplenia funcional en 4 de 79 pacientes con Lupus Eritematoso Sistémico (LES) y en 2 de 18 casos de Síndrome de Sjorgren Primario (SSP). En uno de los pacientes de LES con hipoesplenia funcional y leve esplenomegalia, se demostró ausencia de cuerpos Howell-Jolly en un estudio realizado 11 meses después de la primera evaluación. En el grupo control, un paciente con leucemia linfática crónica (LLC) y esplenomegalia tenía evidencia de hipoesplenismo. Los resultados obtenidos revelan: 1) Las enfermedades autoinmunes que con mayor frecuencia presentan hipoesplenia funcional son el LES y SSP; 2) La hipoesplenia funcional en enfermedades autoinmunes puede ser transitoria. 3) Esplenomegalia e imagen centelleográfica aumentada del bazo no descartan hipoesplenia
Assuntos
Humanos , Masculino , Feminino , Baço/fisiopatologia , Lúpus Eritematoso Sistêmico/fisiopatologia , Síndrome de Sjogren/fisiopatologia , Baço , Inclusões Eritrocíticas/química , TecnécioRESUMO
El objetivo del presente trabajo fue evaluar la existencia de hipoesplenismo funcional en enfermedades autoinmunes. La hipofunción esplénica se determinó por la presencia de cuerpos de Howell-Jolly en eritrocitos de la sangre y posterior centellografía esplénica con radiocoloides marcados con 99Tc, en pacientes en los que se habían descartado otras posibles causas de cuerpo de Howell-Jolly. Se estudiaron extendidos de sangre periférica de 174 pacientes con enfermedades autoinmunes y de 32 otras enfermedades de patogenia inmunológica y 63 indivíduos normales. Se encontró evidencia de hipoesplenia funcional en 4 de 79 pacientes con Lupus Eritematoso Sistémico (LES) y en 2 de 18 casos de Síndrome de Sjorgren Primario (SSP). En uno de los pacientes de LES con hipoesplenia funcional y leve esplenomegalia, se demostró ausencia de cuerpos Howell-Jolly en un estudio realizado 11 meses después de la primera evaluación. En el grupo control, un paciente con leucemia linfática crónica (LLC) y esplenomegalia tenía evidencia de hipoesplenismo. Los resultados obtenidos revelan: 1) Las enfermedades autoinmunes que con mayor frecuencia presentan hipoesplenia funcional son el LES y SSP; 2) La hipoesplenia funcional en enfermedades autoinmunes puede ser transitoria. 3) Esplenomegalia e imagen centelleográfica aumentada del bazo no descartan hipoesplenia (AU)
Assuntos
Humanos , Masculino , Feminino , Baço/fisiopatologia , Lúpus Eritematoso Sistêmico/fisiopatologia , /fisiopatologia , Baço/diagnóstico por imagem , Inclusões Eritrocíticas/química , Tecnécio/diagnósticoRESUMO
A survey of 393 Puerto Rican and 354 non-Hispanic pediatric patients at Beth Israel Hospital, New York, revealed a significantly larger percentage of asthmatic subjects among Puerto Ricans, confirming findings of a study of Puerto Rican adults in New York. Assays of alpha 1-antitrypsin (AAT) concentration and phenotypes in 61 Puerto Rican asthmatic children revealed a significantly larger number with an S or Z variant in AAT phenotype. The AAT concentration was not a significant variable in this relationship, since four of five subjects with intermediate deficient AAT concentrations and a PiM phenotype were among control nonasthmatic Puerto Rican subjects. A family history of asthma was more common among asthmatic than control subjects and was most common for variant AAT phenotypes in either asthmatic or control subjects. We speculate that the S or Z variant of AAT affects the inflammatory response in such a way as to predispose to asthma.
Assuntos
Asma/sangue , Variação Genética , Hispânico ou Latino , alfa 1-Antitripsina/análise , Adolescente , Asma/epidemiologia , Asma/etnologia , Distribuição de Qui-Quadrado , Criança , Feminino , Hispânico ou Latino/estatística & dados numéricos , Humanos , Masculino , Cidade de Nova Iorque/epidemiologia , Fenótipo , Prevalência , Porto Rico/etnologiaRESUMO
UNLABELLED: The objective of this study was to evaluate hyposplenism in autoimmune diseases by the presence of Howell-Jolly bodies in blood erythrocytes and 99Tc spleen scan. Blood smears of 174 patients with autoimmune diseases and 126 controls were studied. Other possible causes for the presence of Howell-Jolly bodies were excluded. Evidence of hyposplenism was demonstrated in 4 of 79 patients with Systemic Lupus Erythematosus (SLE) and in 2 of 18 cases of primary Sjögren Syndrome (PSS), whereas no hyposplenism was found in the remaining cases of other autoimmune diseases. In one of the patients with SLE, hyposplenism was transient. Among the control cases, a patient with Chronic Lymphocytic Leukemia with splenomegaly presented hyposplenism. IN CONCLUSION: 1) Hyposplenism is more frequently found in SLE and PSS than in other autoimmune diseases. 2) Hyposplenism in autoimmune diseases can be transient. 3) Splenomegaly and enlarged spleen scan do not exclude hyposplenism.
Assuntos
Lúpus Eritematoso Sistêmico/fisiopatologia , Síndrome de Sjogren/fisiopatologia , Baço/fisiopatologia , Inclusões Eritrocíticas/química , Feminino , Humanos , Lúpus Eritematoso Sistêmico/sangue , Masculino , Cintilografia , Síndrome de Sjogren/sangue , Baço/diagnóstico por imagem , TecnécioRESUMO
The objective of this study was to evaluate hyposplenism in autoimmune diseases by the presence of Howell-Jolly bodies in blood erythrocytes and 99Tc spleen scan. Blood smears of 174 patients with autoimmune diseases and 126 controls were studied. Other possible causes for the presence of Howell-Jolly bodies were excluded. Evidence of hyposplenism was demonstrated in 4 of 79 patients with Systemic Lupus Erythematosus (SLE) and in 2 of 18 cases of primary Sj÷gren Syndrome (PSS), whereas no hyposplenism was found in the remaining cases of other autoimmune diseases. In one of the patients with SLE, hyposplenism was transient. Among the control cases, a patient with Chronic Lymphocytic Leukemia with splenomegaly presented hyposplenism. In conclusion: 1) Hyposplenism is more frequently found in SLE and PSS than in other autoimmune diseases. 2) Hyposplenism in autoimmune diseases can be transient. 3) Splenomegaly and enlarged spleen scan do not exclude hyposplenism.
RESUMO
Because of the frequency of ocular toxoplasmosis and its occurrence in multiple siblings in southern Brazil, a population-based household survey was performed to better understand the epidemiologic characteristics of the disease in this region. Of 1,042 individuals examined, 184 (17.7%) were deemed to have ocular toxoplasmosis on the basis of conservative assessment of ophthalmic findings. Of those with ocular toxoplasmosis, 183 (99.5%) had specific IgG antibodies, compared with only 140 of 181 age-matched control subjects (77.4%; P less than .001). The prevalence of ocular toxoplasmosis was 0.9% in 1- to 8-year-olds, 4.3% in 9- to 12-year-olds, 14.3% in 13- to 16-year-olds, and 21.3% (95% confidence interval, 18.6% to 24.2%) in all individuals 13 years or older. The prevalence of ocular toxoplasmosis in this population was more than 30 times higher than previous estimates for the same condition elsewhere. The low prevalence in the young children we studied supplements previous data suggesting that, in this population, ocular toxoplasmosis is a sequela of postnatal rather than congenital infection.
Assuntos
Toxoplasmose Ocular/epidemiologia , Adolescente , Adulto , Idoso , Animais , Brasil/epidemiologia , Criança , Pré-Escolar , Feminino , Fundo de Olho , Humanos , Imunoglobulina G/análise , Masculino , Pessoa de Meia-Idade , Prevalência , Fatores de Risco , Toxoplasma/imunologia , Toxoplasmose Ocular/diagnósticoRESUMO
The biosynthesis of thyroid hormones requires iodide, thyroid peroxidase (TPO), thyroglobulin (Tg) and H2O2. We have studied two sisters with congenital large goiters and hypothyroidism. Perchlorate tests were negative. Serum T3 and T4 were decreased, TSH was increased and Tg was within the lower limit of normal. Biochemical and molecular studies were performed on goiter samples obtained after surgery. Tg content in both tissues was negligible. Paper chromatography of labeled iodocompounds showed a decrease in T4, and the presence of a pronase/pancreatin-resistant iodoprotein. TPO activity was normal in the tissues. Sephacryl S-300 gel filtration demonstrated labeled iodoalbumin-like protein and the absence of a Tg peak. Salting out studies of soluble protein fraction gave an abnormal pattern. Agarose gel electrophoresis showed the presence of an iodoalbumin-like protein and the absence of Tg in the tissues. This last finding was confirmed by immunoelectrophoresis. The Tg and TPO mRNAs levels were also analyzed. Dot-blot hybridization studies with pM5 (TPO cDNA) and phTgM2 (Tg cDNA) probes showed increased and decreased signals, respectively. The increase in TPO mRNA can be explained as a compensatory mechanism vis a vis an increase in serum TSH caused by decreased serum T3 and T4 due to the impairment in Tg mRNA. The Tg mRNA of both patients was further studied with four different probes covering 5' and 3' regions (phTgM1, phTgB1, phTgB2 and phTgB3). Hybridization was observed with all four probes, thus excluding a dramatic deletion defect. Northern transfer showed a clear signal of hybridization with the phTgB1 probe in the 8-9 Kb range. We may conclude that the biochemical and molecular abnormality of these patients is characterized by a decrease of Tg mRNA and of Tg translation.
Assuntos
Bócio/congênito , Iodeto Peroxidase/genética , RNA Mensageiro/metabolismo , Tireoglobulina/genética , Adolescente , Western Blotting , Criança , Sondas de DNA , Feminino , Bócio/genética , Humanos , Radioisótopos do Iodo , Hibridização de Ácido Nucleico , Tireoglobulina/biossíntese , Tireotropina/sangue , Tiroxina/sangue , Tri-Iodotironina/sangueRESUMO
We evaluated the efficacy of an antihistamine-decongestant combination as adjunctive therapy in the treatment of acute otitis media with effusion. In a randomized study, 53 children were treated for acute otitis media with antibiotics and either Naldecon or placebo. Subjects were evaluated by tympanometry and pneumotoscopy. Follow-up evaluation was performed at days seven and 14 of therapy. The antihistamine-decongestant prescription was found to influence both the duration of nasal congestion and the course of middle ear effusion: Naldecon-treated subjects were symptomatic with nasal congestion for an average of six days compared to nine days reported by those given placebo, and the risk of persisting middle ear effusion was approximately two times greater in the placebo-treated group when evaluated by tympanometry.
Assuntos
Amoxicilina/uso terapêutico , Compostos Benzidrílicos/uso terapêutico , Clorfeniramina/uso terapêutico , Antagonistas dos Receptores Histamínicos H1/uso terapêutico , Descongestionantes Nasais/uso terapêutico , Otite Média com Derrame/tratamento farmacológico , Otite Média/tratamento farmacológico , Fenilefrina/uso terapêutico , Fenilpropanolamina/uso terapêutico , Testes de Impedância Acústica , Adolescente , Criança , Pré-Escolar , Ensaios Clínicos como Assunto , Combinação de Medicamentos/uso terapêutico , Quimioterapia Combinada , Humanos , Lactente , Medicamentos Compostos contra Resfriado, Influenza e Alergia , Distribuição AleatóriaRESUMO
Human gastric juice samples were investigated from high- and low-risk areas (Colombia and Boston) for factors which influence the stability of nitrite and its potential for nitrosamine formation. The samples from individuals with chronic atrophic gastritis and intestinal metaplasia were not reactive to nitrite and supported a rate of nitrosation largely compatible with the nitrite and thiocyanate concentration. The samples from other individuals contained factors which destroyed nitrite and inhibited nitrosation. There were several samples from both groups which had an elevated rate of nitrosation catalyzed by unknown factors. It is suggested that continued hypochlorhydria might deplete gastric juice of its natural protective factors and lead to an elevated risk of gastric cancer in agreement with our earlier etiological model [1].
Assuntos
Suco Gástrico/metabolismo , Gastrite Atrófica/metabolismo , Gastrite/metabolismo , Nitritos/metabolismo , Nitrosaminas/metabolismo , Colômbia , Humanos , Massachusetts , Nitratos/metabolismo , Risco , Tiocianatos/metabolismoRESUMO
Samples of gastric contents from 2 groups of patients from a region of high risk for gastric cancer were analyzed for pH, nitrite, nitrate, thiocyanate, and chloride. In each group, the patients could be divided into 2 subgroups: those with a gastric pH of less than 5 and those with a gastric pH of greater than 5. Above pH 5, nitrite was correlated with nitrate. The pH greater than 5 subgroups had significantly higher (P less than 0.01) nitrite content (20- to 100-fold). Some high- and low-nitrite samples were also analyzed for macro and trace metal ions, but differences were not significant. This is the first report in which patients with diagnosed gastric pathology related to a precancerous state were shown to have high levels of a putative carcinogen precursor. The results were compatible with our original hypothesis of intragastric nitrite formation by bacterial reduction of nitrate and concomitant synthesis of carcinogenic N-nitroso compounds.