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J Parsonnet

Publications and source records attributed to J Parsonnet.

At least 19 recordsLinked to original sources
PubMed2005

Concordance of Helicobacter pylori infection among children in extended-family homes.

Helicobacter pylori is transmitted within households and high concordance is observed among siblings. To better understand the contributions of close interpersonal contact and family relatedness to transmission, we compared concordance of H. pylori infection among 241 sibling and non-sibling children aged 2-18 years in 68, predominantly low-income, Hispanic households with at least two nuclear families. Prevalence of H. pylori infection was 24%. Compared to children with no infected siblings or non-siblings and adjusting for age, odds of H. pylori infection were 1.2 (95% CI 0.52-2.9), 3.2 (95% CI 1.14-9.1), and 9.4 (95% CI 3.1-28.5) for children residing with at least one infected non-sibling, one infected sibling, and with at least one infected sibling and non-sibling, respectively. The study further implicates intersibling transmission as a pathway for H. pylori infection in childhood. In addition, living with a non-sibling in extended-family homes may contribute to infection risk but only in households with prevalent H. pylori infection within all family groups.

Adolescent↗
PubMed2005

QuantiFERON-TB predicts tuberculin skin test boosting in U.S. foreign-born.

SETTING: Santa Clara County, Northern California. OBJECTIVE: To characterize agreement of tuberculin skin test (TST) and QuantiFERON-TB (QFT) with repeated testing. DESIGN: Fifty-two subjects participating in an ongoing prospective study of infectious disease transmission were tested by TST and QFT at two home visits 3 months apart. Boosting was defined as reclassification of TST from negative to positive. Agreement and reproducibility of TST and QFT were assessed using kappa and McNemar statistics. RESULTS: Of 48 individuals completing all tests, 75% were foreign-born (92% Latin America) and 58% were BCG-vaccinated. Initial TST and QFT were positive in 13 (27%) and 21 (44%), respectively, with an overall agreement of 67% (K = 0.29). Ten (29%) of 35 initial TST-negative reactions boosted, nine of whom were BCG-vaccinated subjects. Boosting occurred in eight (67%) of 12 subjects who were initially QFT-positive/TST-negative. Compared to the second TST, initial QFT had a relative post-test probability of 76% (95% CI 0.58-0.95); boosting accounted for 8/16 (50%) of initial testing discordances. CONCLUSION: Positive QFT in the setting of negative TST frequently anticipates a TST boost. This finding helps explain discordance between the two tests and may provide an alternative to serial TST testing.

Adolescent↗
PubMed2003

No association between Helicobacter pylori and Mycobacterium tuberculosis infections among gastrointestinal clinic attendees in Lima, Peru.

Helicobacter pylori (HP) infection can cause hypochlorhydria, a positive risk factor for Mycobacterium tuberculosis (MTB) infection. This study examined the association between HP and MTB infections among persons attending the Policlinico Peruano Japonés Gastrointestinal Clinic in Lima, Peru. From 23 June 2000 to 18 August 2000, consenting 18-55 year olds who attended the clinic for gastric biopsy gave blood for HP serologic testing, underwent tuberculin skin testing (TST) and completed a social and medical history. Of 128 participating patients, 78 (61%) were TST positive for MTB, and 107 (84%) were infected with HP by serology. Of the patients who were HP positive, 67 (63%) developed positive TST reactions compared to 11 (52%) of 21 HP-seronegative subjects (OR 1.29; 95% CI 0.54-3.11; P = 0.6). There was no association after adjusting for covariates of H. pylori infection (OR 0.78; 95% CI 0.23-2.71; P = 0.7). However, study power was limited by high prevalence of the two infections.

Adolescent↗
PubMed2002

A modification of the quininium resin test for assessing gastric acidity.

BACKGROUND: Gastric acid is an important defence against enteric infection. Studies investigating the relationship between hypochlorhydria and enteric infections or gastric malignancy have been limited by difficulties in the non-invasive measurement of gastric acidity. AIM: To develop a blood test for hypochlorhydria based on the quininium resin test. METHODS: Quininium resin dissociates to liberate free quinine at pH <or= 3.5. Ten fasting adult volunteers ingested 100 mg/kg of quininium resin twice: once before (control) and once after acid suppression with rabeprazole (10 mg b.d. for 3 days). Blood and serum samples were collected at baseline and 45, 60, 75, 90 and 120 min after ingestion. Quinine levels were measured fluorometrically from 100 microL samples after simple extraction. Results obtained by the quininium resin test were compared with gastric juice pH measurements. RESULTS: After quininium resin ingestion, mean quinine levels were lower in the acid-suppressed than in the control condition at all times (P < 0.001). Optimized cut-off values at 90 min post-ingestion yielded 95% accuracy rates in both serum and blood. Quininium resin was well tolerated. CONCLUSIONS: Using blood or serum, the quininium resin test identifies hypochlorhydria accurately and non-invasively. This test may be useful in screening for gastric atrophy and in studies investigating hypochlorhydria.

2-Pyridinylmethylsulfinylbenzimidazoles↗
PubMed2001

Quantifying the population impact of a prophylactic Helicobacter pylori vaccine.

BACKGROUND: Helicobacter pylori vaccines, which have been suggested as promising interventions to control infection, are under development. We sought to quantify the potential population impact of a prophylactic H. pylori vaccine. METHODS: We developed a mathematical model that compartmentalized the population according to age, infection status and clinical state. A proportion of individuals was assumed to acquire infection and develop gastritis, duodenal ulcer (DU), chronic atrophic gastritis and gastric cancer (GC). We first simulated the model without vaccine intervention, to obtain estimates of H. pylori prevalence, and GC and DU incidences based on intrinsic dynamics. We then incorporated a prophylactic vaccine (80% efficacy, lifetime protection, 80% coverage) targeting all infants. We tested vaccination programs over unlimited as well as limited time spans. Analyses were performed for the US, Japan and a prototypical developing country. RESULTS: In the US, our model predicted a decrease in H. pylori prevalence from 12.0% in 2010 to 4.2% in 2100 without intervention. With 10 years of vaccination beginning in 2010, prevalence would decrease to 0.7% by year 2100. In the same period, incidence of H. pylori-attributable GC would decrease from 4.5 to 0.4 per 100,000 with vaccine (compared to 1.3 per 100,000 without vaccine). Incidence of H. pylori-attributable DU would decrease from 33.3 to 2.5 per 100,000 with vaccine (compared to 12.2 per 100,000 without vaccine). In Japan, incidence of H. pylori-attributable GC would decrease from 17.6 to 1.0 per 100,000 after 10 years of vaccination (compared to 3.0 per 100,000 without vaccine). In a prototypical developing country, after 10 years of vaccination, H. pylori-attributable GC would decrease from 31.8 to 22.5 per 100,000 by 2090, returning to the original level by mid-2100s. Under continuous vaccination, it would decrease to 5.8 per 100,000 by 2100. INTERPRETATION: In the US and Japan, a 10-year vaccination program would confer almost the same reduction in H. pylori and associated diseases as a vaccination effort that extends beyond 10 years. In developing countries, a continuous vaccination effort would be required to eliminate the pathogen and its associated diseases.

Developing Countries↗
PubMed2001

Recurrent nonmenstrual toxic shock syndrome: clinical manifestations, diagnosis, and treatment.

We report 3 cases of recurrent nonmenstrual toxic shock syndrome (TSS) and review the clinical manifestations, diagnosis, and treatment. The primary sites of infection were the genital tract (in a patient who underwent cesarean delivery), the upper respiratory tract, and a breast abscess. In all 3 patients, the initial illness was not recognized to be TSS; only after development of recurrent illness with desquamation was this diagnosis entertained. Strains of Staphylococcus aureus that were isolated from 2 patients produced TSS toxin-1, whereas the third strain produced staphylococcal enterotoxin B. All 3 patients lacked antibody to the implicated toxins at the time of presentation with recurrent illness. Nonmenstrual TSS can occur in a variety of clinical settings and may be recurrent. The presence of desquamation during a febrile, multisystem illness could suggest this diagnosis and should prompt the clinician to obtain appropriate cultures for S. aureus.

Adult↗
PubMed2001

Gastric atrophy and extent of intestinal metaplasia in a cohort of Helicobacter pylori-infected patients.

Atrophy and intestinal metaplasia (IM) are preneoplastic gastric lesions associated with Helicobacter pylori infection. Atrophy and IM are usually found together; however, the association between increasing degrees of severity of both atrophy and IM has not been evaluated completely. Two pathologists graded atrophy and IM using the visual analog scale of the Sydney classification in gastric biopsies from 368 H pylori-infected patients. Extent of IM also included determining the number of specimens affected. We then correlated the degree of atrophy with the degree and number of specimens affected with IM by calculating relative risks (RR) and 95% confidence intervals (95% CI). The mean number of biopsies examined from each patient was 6.5. Atrophy and IM were found more frequently in the antrum (85% and 75% of biopsies, respectively). One hundred thirty-eight patients had a combination of atrophy and IM, 48 had IM only, and 89 had atrophy only. Fifty-three subjects had mild atrophy and IM (RR = 1.57; 95% CI 1.2-2.1), 69 had moderate atrophy and IM (RR = 1.86; 95% CI 1.9-2.4), and 16 had marked atrophy and IM (RR = 2.47; 95% CI 1.8-3.3). The median number of biopsy specimens with IM increased from 0 in subjects with no atrophy to 3 in subjects with severe atrophy. The degree of IM correlated with the degree of atrophy; the median degree was 0.6 in subjects with no atrophy and increased to 2.32 in those with severe atrophy. Our data suggest that higher degrees of IM in an individual specimen and increasing number of specimens with IM are associated with moderate or severe degrees of atrophy.

Adult↗
PubMed2001

Confirmatory serologic testing for acute toxoplasmosis and rate of induced abortions among women reported to have positive Toxoplasma immunoglobulin M antibody titers.

OBJECTIVE: Results obtained with commercial testing kits for immunoglobulin M Toxoplasma antibodies may be inaccurate or may be inaccurately interpreted, which may influence whether a woman decides to terminate the pregnancy. This study was undertaken to determine whether confirmatory testing at a reference laboratory and communication of the results and an expert interpretation to the patient's physician would affect the rate of induced abortions among pregnant women with positive results of testing for immunoglobulin M Toxoplasma antibodies in outside laboratories. STUDY DESIGN: This was a retrospective cohort study of 811 consecutive pregnant women for whom the toxoplasma serologic profile was performed at a reference laboratory. Almost all the patients had been informed by their physicians that a result of a test for immunoglobulin M Toxoplasma antibodies performed in an outside laboratory was positive. Women were separated into those with a toxoplasma serologic profile result suggestive of a recently acquired infection (group 1) and those with a result suggestive of an infection acquired in the more distant past (group 2). Physician reports of induced abortions were used to determine rates of induced abortion in groups 1 and 2. RESULTS: Of the 811 women 321 (39.6%) were considered likely to have a recent infection (group 1) and 490 (60.4%) were considered likely to have a past infection (group 2). Physicians reported pregnancy outcomes for 433 (53.4%) of 811 women (65.1% and 45.7% in groups 1 and 2, respectively). Whereas 36 of 209 women in group 1 (17.2%) terminated the pregnancy, only 1 of 224 women in group 2 (0.4%) chose abortion (P <.001). CONCLUSION: Confirmatory serologic testing in a reference laboratory and communication of the results and their correct interpretation by an expert to the patient's physician decreased the rate of unnecessary abortions by approximately 50% among women for whom positive immunoglobulin M Toxoplasma test results had been reported by outside laboratories.

Abortion, Induced↗
PubMed2001

Determination of the infectious dose of Helicobacter pylori during primary and secondary infection in rhesus monkeys (Macaca mulatta).

We sought to determine the infectious dose of Helicobacter pylori during primary and secondary infection in the rhesus monkey and to determine whether preinoculation acid suppression is necessary to produce colonization. Mixed inoculation with three human-derived strains showed that H. pylori J166 is particularly adapted to colonization of rhesus monkeys, since it outcompeted two other strains. The minimum infectious dose of H. pylori J166 was 10(4) bacteria in specific-pathogen (H. pylori)-free monkeys. Rechallenge of these monkeys after antibiotic therapy was characterized by a 10- to 100-fold decrease in bacterial load compared to primary infection, but with little change in the infectious dose. Acid suppression prior to inoculation was not necessary for colonization to occur. These results provide a basis for future animal experiments using more ecologically relevant conditions of inoculation and suggest that reduction in bacterial load rather than complete protection may be a more realistic goal for H. pylori vaccination.

Acids↗
PubMed2001

Acute Helicobacter pylori infection is followed by an increase in diarrheal disease among Peruvian children.

BACKGROUND: Cohort and case-crossover studies were conducted to evaluate whether new Helicobacter pylori infections are followed by increased diarrhea. METHODS: Participants were 6-month-old to 12-year-old shantytown residents living near Lima, Peru. Baseline data were collected from community households. Health interviews were completed daily, and sera, drawn every 4 months, were tested for H pylori immunoglobulin G. Diarrhea rates among newly H pylori-infected (seroconverting) children were compared with rates among persistently uninfected and infected children using cohort and case-crossover analyses. RESULTS: Sera were obtained from 345 children from January 1, 1995, through September 1, 1997. H pylori incidence was 12% per year (36 H pylori infections in 109 866 seronegative days). In adjusted cohort analyses, seroconverters had more diarrhea days (rate ratio: 2.0; 95% confidence interval: 1.6-2.4), episodes, and sick days in the year after infection than did uninfected children; and more diarrhea days and sick days than did persistently infected children. This effect was strongest in the first 2 months. Case-crossover analyses supported these findings. CONCLUSION: Preventing H pylori infection may help reduce pediatric diarrheal disease.

Acute Disease↗
PubMed2001

Histological classification of gastric adenocarcinoma for epidemiological research: concordance between pathologists.

Epidemiology of gastric adenocarcinoma suggests that intestinal-type and diffuse-type cancers develop through distinct causal pathways. To examine the differences in risk factors and molecular changes between the histological types, reliable data on histological typing are essential. We evaluated the concordance between two pathologists in assessment of 95 gastric adenocarcinomas for Laurén classification and tumor grade. Two pathologists, each blinded to the other's assessment, reviewed H&E-stained slides of gastric tumor. The responses of the two pathologists for histological type were considered as concordant if they fell on one of the three categories (intestinal type, diffuse type, or other). Tumor grade was classified into three categories (well, moderately, or poorly differentiated). The pathologists agreed on the classification of histological type for 71 of 92 (77%) tumors. Kappa coefficient was 0.59 (95% confidence interval, 0.44-0.73). Concordance for tumor grade was 87%, with a kappa coefficient of 0.72 (95% confidence interval, 0.57-0.87). Both observed concordance and kappa coefficient for histological type and tumor grade were similar across three calendar periods of study. Interobserver agreement was virtually identical between tumors with biopsy specimens only and those with surgical specimens. Although the level of disagreement for histological type observed in this study is comparable with that in other studies, the resulting misclassification would lead to the reduction in observed differences in prevalence and odds ratio estimates between two histological types.

Adenocarcinoma↗
PubMed2001

Screening markers for chronic atrophic gastritis in Chiapas, Mexico.

Intestinal-type gastric adenocarcinomas usually are preceded by chronic atrophic gastritis. Studies of gastric cancer prevention often rely on identification of this condition. In a clinical trial, we sought to determine the best serological screening method for chronic atrophic gastritis and compared our findings to the published literature. Test characteristics of potential screening tests (antibodies to Helicobacter pyloni or CagA, elevated gastrin, low pepsinogen, increased age) alone or in combination were examined among consecutive subjects enrolled in a study of H. pylori and preneoplastic gastric lesions in Chiapas, Mexico; 70% had chronic atrophic gastritis. English-language articles concerning screening for chronic atrophic gastritis were also reviewed. Sensitivity for chronic atrophic gastritis was highest for antibodies to H. pylori (92%) or CagA, or gastrin levels >25 ng/l (both 83%). Specificity, however, was low for these tests (18, 41, and 22%, respectively). Pepsinogen levels were highly specific but insensitive markers of chronic atrophic gastritis (for pepsinogen I <25 microg/l, sensitivity was 6% and specificity was 100%; for pepsinogen I:pepsinogen II ratio <2.5, sensitivity was 14% and specificity was 96%). Combinations of markers did not improve test characteristics. Screening test characteristics from the literature varied widely and did not consistently identify a good screening strategy. In this study, CagA antibodies alone had the best combination of test characteristics for chronic atrophic gastritis screening. However, no screening test was both highly sensitive and highly specific for chronic atrophic gastritis.

Adult↗
PubMed2001

Helicobacter pylori and risk for gastric adenocarcinoma.

Gastric cancer is the second most common cause of cancer death in the world. Helicobacter pylori infection is now a well-accepted cause of this malignancy; in some parts of the world, up to eighty percent of all gastric cancers are at least in part caused by H. pylori infection. H. pylori infection typically starts in childhood as an inflammatory process in the stomach. The changes in the gastric microenvironment facilitate gastric cancer over time. Among infected individuals, genotype of H. pylori, coincident environmental exposures, and genetic factors of host seem to play roles in determining who will get gastric cancer and who will not. Unfortunately, it remains unknown whether treatment of H. pylori prevents gastric cancer. Thus, screening for H. pylori to prevent cancer is not yet widely recommended. Some consensus groups, however, have recommended screening for and treating H. pylori infection in individuals with family histories of gastric malignancy. In high-risk countries, screening programs for early gastric cancer itself may improve therapeutic outcome for this highly lethal disease.

Adenocarcinoma↗
PubMed1999

Fecal and oral shedding of Helicobacter pylori from healthy infected adults.

CONTEXT: Helicobacter pylori commonly infects humans; however, its mode of transmission remains unknown. OBJECTIVE: To determine how humans-the primary host for H pylori-shed the organism into the environment. DESIGN: Controlled clinical experimental study conducted from February through December 1998. SETTING: Clinical research unit of a hospital in northern California. PATIENTS: Sixteen asymptomatic H pylori-infected and 10 uninfected adults. INTERVENTION: A cathartic (sodium phosphate) and an emetic (ipecac) were given to all infected subjects and an emetic was given to 1 uninfected subject. MAIN OUTCOME MEASURE: Confirmed H pylori isolates cultured from stool, air, or saliva before and after catharsis and emesis and from vomitus during emesis. Isolates were fingerprinted using repetitive extragenic palindromic (REP) polymerase chain reaction and species identity was confirmed by sequencing the 16s ribosomal RNA gene. RESULTS: All vomitus samples from infected subjects grew H pylori, often in high quantities. Air sampled during vomiting grew H pylori from 6 (37.5%) of the 16 subjects. Saliva before and after emesis grew low quantities of H pylori in 3 (18.8%) and 9 (56.3%) subjects, respectively. No normal stools and only 22 (21.8%) of 101 induced stools grew the organism, although 7 (50.0%) of 14 subjects had at least 1 positive culture (2 stool culture samples were contaminated by fungus and were not included). Fingerprints of isolates within subjects were identical to one another but differed among subjects. No samples from uninfected subjects yielded H pylori. CONCLUSIONS: Helicobacter pylori can be cultivated uniformly from vomitus and, occasionally, from saliva and cathartic stools. The organism is potentially transmissible during episodes of gastrointestinal tract illness, particularly with vomiting.

Adult↗