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Biomedical subjects

R M Genta

Publications and source records attributed to R M Genta.

At least 73 records · Page 4Linked to original sources
PubMed1997

Comparison of agar gel (CLOtest) or reagent strip (PyloriTek) rapid urease tests for detection of Helicobacter pylori infection.

OBJECTIVE: Rapid urease tests (RUTs) are used commonly as a convenient method to detect Helicobacter pylori infection. New rapid tests have been commercially available with promotional literature suggesting enhanced utility. We compared CLOtest to a new reagent strip RUT, PyloriTek. METHODS: Gastric antral mucosal biopsy specimens were obtained from 102 patients for comparison between CLOtest and PyloriTek (204 specimens). Biopsy specimens obtained from a nearby area were stained using the Genta stain for determination of H. pylori status. The RUT to be used first was selected randomly. RESULTS: Sixty-five of the 102 patients had peptic ulcer disease, two had gastric cancer, and 35 had dyspepsia; 61 patients had active H. pylori infection. There were one false-negative and three false-positive CLOtest results, compared with one false-negative and 13 false-positive PyloriTek results (p < 0.02 for incorrect categorization with PyloriTek). Sensitivity and specificity were 98 and 92% compared with 98 and 68% for CLOtest and PyloriTek, respectively. An erroneous categorization of H. pylori status occurred in 3.9% (95% confidence interval [CI]: 1-9.7%) with CLOtest compared with 13.7% (95% CI: 7.7 -22%) with PyloriTek. When the PyloriTek was scored at 1 h (0-1 h) after obtaining the specimen, the accuracy improved; erroneous categorization of H. pylori status occurred in only 2.9% (95% CI: 0.6-8.3%). CONCLUSION: Used according to manufacturer instructions, the new reagent strip RUT PyloriTek has too many false-positive results for use in a clinical situation. In contrast, when the test was interpreted within 1 h, accuracy was comparable to that of CLOtest.

Adult↗
PubMed1996

Evaluation of a new reagent strip rapid urease test for detection of Helicobacter pylori infection.

BACKGROUND: Rapid urease tests are commonly used as a convenient method to detect Helicobacter pylori infection. Our previous experiments demonstrated enhanced efficacy of agar gel rapid urease test compared with reagent strip rapid urease tests. We evaluated the efficacy of PyloriTek, a new reagent strip rapid test for detecting H. pylori infection. METHODS: Gastric antral mucosal biopsy specimens were obtained for comparison between agar gel rapid urease tests and PyloriTek (200 specimens). The rapid urease test to be used first was selected randomly. H. pylori status was determined using the Genta stain. Culture was performed to confirm H. pylori status when false rapid urease tests were suspected. RESULTS: One hundred patients were studied; 68 had H. pylori infection. There were two false-negative and one false-positive PyloriTek when scored at 1 hour, compared with only one false-positive and no false-negative tests at 2 hours. With the agar gel rapid urease tests, there were no false-positive tests and 5 false-negative tests when scored at 1 hour, 2 false-negative tests at 12 hours and 1 at 24 hours; there were no false-positive tests. At 1 hour, 3% (95% CI = 1% to 9%) of PyloriTek tests had an erroneous categorization of H. pylori status compared with 5% for the agar gel rapid urease tests (95% CI = 1.6% to 11%) (p > 0.7). CONCLUSION: The new reagent strip rapid urease test, PyloriTek, is rapid and comparable in accuracy to agar gel rapid urease tests for detecting H. pylori Infection.

Adult↗
PubMed1996

Detection of Helicobacter pylori by rapid urease tests: is biopsy size a critical variable?

BACKGROUND: The variables responsible for false-positive and false-negative rapid urease tests are largely unexplored. OBJECTIVES: We compared the results of rapid urease testing with jumbo cup forceps (3.3 mm diameter) and tiny cup forceps (1.8 mm diameter) with two rapid urease tests. METHODS: Antral biopsies were obtained. The order of forceps and rapid urease tests was randomized. Biopsies were also taken for Genta staining. RESULTS: One hundred and two patients were studied; 59 had Helicobacter pylori infection. There were 22 false-negative tests (8 CLOtest, 16 hpfast) and 5 false-positive tests (3 CLOtest, 2 hpfast). All 5 false-positive tests were among those positive only in the second 12 hours. There was no difference in results with the jumbo and tiny cup forceps. Five percent to nine percent (average, 6.6%; 95% confidence interval, 4.4% to 9.6%) of tests with any of the combinations gave an erroneous categorization of H. pylori status. There were no clinical or statistical differences in H. pylori categorizations by CLOtest or hpfast. CONCLUSION: The diagnostic yield for detecting H. pylori infection by rapid urease tests is not adversely affected by small biopsy size, possibly because tiny biopsies obtain superficial tissue where H. pylori reside.

Biopsy↗
PubMed1996

Interobserver variation in the histopathological assessment of Helicobacter pylori gastritis.

The histopathologic detection of Helicobacter pylori in gastric biopsy specimens is considered the gold standard for the diagnosis of H pylori infection. However, few studies have addressed the pathologists' reliability to detect the organism and to assess the degree of the related inflammatory changes. The objectives of this study were to determine the degree of agreement among the findings of four gastrointestinal pathologists in the semiquantitative evaluation of H pylori infection and gastritis. Three slides from specified areas of the stomach of 99 patients with and without H pylori infection were stained with the triple stain, coded, and examined independently by four pathologists. For each specimen, a visual analogue scale graded from 0 (absent/normal) to 5 (maximal intensity) was used to score (1) H pylori (2) neutrophils, and (3) atrophy. Data were analyzed using kappa-statistics. The kappa-coefficient for the detection of H pylori (present vs absent) was approximately .9 (excellent); for the intensity of infection, it was considerably lower on the 6-point scale (approximately .61) and improved slightly on an amalgamated 4-point scale (approximately .71). The agreement on presence or absence of neutrophils was excellent (kappa = .8) in antral biopsies and good (kappa = .67) in corpus biopsies. The kappa for the semiquantitative scoring of neutrophils was poor on the 6-point scale (approximately .43) and fair on the amalgamated scale (approximately .54). The interobserver agreement was the poorest in the evaluation of atrophy (presence, absence, categories, or group categories) with kappa coefficients varying from .08 and .29. This group of pathologists had a high level of concordance on the diagnosis of H pylori infection in any particular patient and a high index in the assessment of the intensity of infection. The agreement was less in the semiquantitative evaluation of active inflammation. When the evaluation concerned a loosely defined feature, such as atrophy, there was essentially no agreement among the pathologists. This study suggests the need for further assessments of pathologists' ability to provide reproducible diagnoses. These results also indicate that more stringent criteria for the diagnosis of "soft" histopathologic features (such as atrophy) are urgently needed.

Atrophy↗
PubMed1996

Histological features do not define NSAID-induced gastritis.

Nonsteroidal anti-inflammatory drug (NSAID) use is a common cause of peptic ulcer. This study investigated the nature, frequency, and topographic distribution of histological abnormalities of the gastric mucosa associated with chronic NSAID use. A set of 3 to 11 mapped gastric biopsy specimens were obtained from 108 chronic users of NSAIDs and 61 controls. Each specimen was graded from 0 to 3 for each of the following features: foveolar hyperplasia, smooth muscle fibers, edema, neutrophils, intestinal metaplasia, eosinophils, mononuclear cells, mucosal hemorrhage, atrophy, and Helicobacter pylori. We found that foveolar hyperplasia, considered one of the characteristic features of chemical gastropathy, was absent in 66% of NSAID users. Foveolar hyperplasia was present in 37 NSAID users (34%) and in 10 controls (18%); prominent smooth muscle fibers were found in 51 NSAID users (47%) and 10 of the controls (16%). Concurrent H pylori gastritis obscured the histopathologic changes of NSAID use. All other parameters, including H pylori infection rate (57% v 51%) were similar in NSAID users and controls. We conclude that the histological features characteristic of NSAID users were present only in a subset of patients. No single histological feature can be used to characterize or diagnose chemical gastropathy and no simple set of diagnostic criteria can be applied for this purpose.

Adult↗
PubMed1996

One-week triple therapy with omeprazole, amoxycillin and clarithromycin for treatment of Helicobacter pylori infection.

BACKGROUND: Multi-drug regimens are generally required to reliably cure H. pylori infection. We previously demonstrated that a 2-week three-times-a-day regimen of amoxycillin and clarithromycin was effective against H. pylori infection. OBJECTIVES: To evaluate the efficacy and side-effects of a 1-week twice-daily dosing schedule for the treatment of H. pylori infection. METHODS: We studied the efficacy of 1-week of therapy with 20 mg of omeprazole, 1 g of amoxycillin and 250 mg of clarithromycin, all twice daily H. pylori status was determined at entry and 4 or more weeks after completing antimicrobial therapy using histology (Genta stain) and culture. RESULTS: Thirty-one patients with documented peptic ulcer disease and H. pylori infection were treated. The H. pylori infection was cured in 24 (77%, 95% CI = 58-90%) (intention-to-treat). In a per protocol analysis the cure rate was 23 of 29 patients (79%, 95% CI = 60-92%). One patient took only 43% of the study drugs and another withdrew following development of an anaphylactic reaction to study medication. Mild side-effects were reported by 16% including diarrhoea, headache and altered taste. Compliance averaged 95%. Pretreatment clarithromycin resistance averaged 5% and had not been acquired by any strains post-therapy. CONCLUSION: This combination of omeprazole, amoxycillin and low-dose clarithromycin resulted in a relatively low cure rate even in patients with clarithromycin-sensitive isolates. Large comparative studies will be needed to define the optimal duration, dose and dosing interval if this combination of drugs is to become competitive.

Adult↗
PubMed1996

High-dose proton pump inhibitor plus amoxycillin for the treatment or retreatment of Helicobacter pylori infection.

BACKGROUND: The combination of 120 mg of omeprazole (40 mg t.d.s.) and amoxycillin has been reported to be effective for treating H. pylori infections. METHODS: Normal volunteers with H. pylori infection received high-dose omeprazole (40 mg t.d.s.) or lansoprazole (60 mg t.d.s.) plus amoxycillin 750 mg t.d.s. for 14 days. The studies were open label and not randomized as those receiving omeprazole plus amoxycillin had previously failed lower dose omeprazole (20 mg b.d.) plus amoxycillin therapy more than 6 months previously. Those receiving lansoprazole plus amoxycillin had not been previously treated. Four to 6 weeks after ending antimicrobial therapy, H. pylori status was determined by Genta stain of gastric mucosal biopsies. RESULTS: Forty-three volunteers entered the study and 41 completed it. The overall success with high-dose proton pump inhibitor plus amoxycillin was 34.9%. For the individual regimens the per-protocol results were 48% (95% CI = 28-69%) with lansoprazole and 12.5% (95% CI = 2-38%) with omeprazole. Compliance was > 95% for both regimens. Side-effects were experienced by four lansoprazole and three omeprazole subjects, and caused two omeprazole subjects to withdraw. Cure rates were similar among different races and ethnic groups, between men and women, and between smokers and non-smokers. The level of the pre-treatment urea breath test also did not predict outcome. CONCLUSION: High-dose proton pump inhibitor plus amoxycillin combinations for treatment of H. pylori infection yielded unacceptable results, as the 95% confidence intervals did not include an 80% cure rate. These combinations do not yield consistent results worldwide and cannot be recommended as primary therapy.

2-Pyridinylmethylsulfinylbenzimidazoles↗
PubMed1996

Effect of hepatocyte proliferation and cellular DNA synthesis on hepatitis B virus replication.

BACKGROUND & AIMS: Interrelationship between hepatitis B virus (HBV) replication and the stage of hepatocyte proliferation and differentiation may play an important role in the pathogenesis of HBV infection. The aim of this study was to assess the effect of hepatocyte proliferation and/or cell arrest on HBV replication. METHODS: Hepatoblastoma cells transfected with HBV were subjected to serum deprivation or treatment with aphidicolin or camptothecin. Cell cycle analysis was performed using flow cytometry, and cellular DNA synthesis was analysed by assessing 5-bromo-2'-deoxyuridine incorporation. Distribution of episomal HBV DNA and proliferating cell nuclear antigen in liver specimens was assessed by simultaneous in situ hybridization and immunohistochemistry. RESULTS: Serum deprivation inhibited cellular DNA synthesis and increased levels of HBV messenger RNA (mRNA). Aphidicolin treatment resulted in cell arrest in C1, with concomitant increases in levels of HBV mRNA and viral DNA. Cell entry into S phase inhibited expression of HBV mRNA. Camptothecin induced G2 cell arrest and inhibited cellular DNA synthesis with increased amounts of viral replication and levels of HBV mRNA. In vivo studies showed an inverse correlation between expression of proliferating cell nuclear antigen and presence of episomal HBV DNA in individual hepatocytes. CONCLUSIONS: HBV replication is cell cycle dependent, supporting the concept of enhanced viral replication in quiescent hepatocytes. The results may explain the mechanism of viral elimination during cell regeneration.

Cell Cycle↗
PubMed1996

Adherence of Helicobacter pylori to areas of incomplete intestinal metaplasia in the gastric mucosa.

BACKGROUND & AIMS: Helicobacter pylori is not usually found in areas of intestinal metaplasia. Thus, the development of intestinal metaplasia has been viewed as a mechanism by which the stomach eliminates H. pylori. The aim of this study was to evaluate the frequency of H. pylori adherence to intestinal metaplasia in different populations. METHODS: Mapped gastric biopsy specimens from 378 H. pylori-positive subjects from various geographical regions were examined. Intestinal metaplasia was typed by staining with periodic acid-Schiff/alcian blue and high-iron diamine/alcian blue. RESULTS: In 32 patients, H. pylori was found in intimate contact with intestinal metaplasia. This was documented by electron microscopy. All areas of intestinal metaplasia showing adherence contained sulfomucins and had no brush border. Posttreatment biopsy specimens from 4 patients whose infection was not cured showed persistence of H. pylori in intestinal metaplasia. CONCLUSIONS: These patients may have a strain of H. pylori with unusual adhesion characteristics, or their type of intestinal metaplasia may have biochemical properties that make it hospitable for H. pylori. The exclusive association of H. pylori adherence with incomplete intestinal metaplasia (a putative precursor of carcinoma) and its greater frequency in Koreans (a population at risk for gastric cancer) suggest that this phenomenon may play a role in the hypothetical sequence metaplasia > dysplasia > carcinoma.

Bacterial Adhesion↗
PubMed1996

Ulcer site and complications: relation to Helicobacter pylori infection and NSAID use.

BACKGROUND AND STUDY AIM: The aim of this study was to investigate the relationship between the presence and location of ulcers, H. pylori infection, NSAID use, and major upper gastrointestinal tract bleeding. PATIENTS AND METHODS: We studied 100 consecutive patients with duodenal ulcers and 145 consecutive patients with benign gastric ulcers. RESULTS: Ninety-nine percent of the duodenal ulcer patients and 92% of the gastric ulcer patients had H. pylori infection; all gastric ulcer patients without H. pylori infection were using NSAIDs. Gastric ulcers in patients with H. pylori infection who were not using NSAIDs were more likely to be on the lesser curvature (85%) than ulcers in NSAID users who had no H. pylori infection (35%) (p < 0.01). Conversely, only 5% of gastric ulcers in H. pylori-positive patients who were not using NSAIDs were on the greater curvature, compared to 45% in H. pylori-negative NSAID users (p < 0.01), and 23% in patients with both possible etiologies. The frequency of NSAID use was very high in patients presenting with upper gastrointestinal tract bleeding: 21 of 25 with gastric ulcers (84%) and 13 of 21 with duodenal ulcers (62%; p < 0.01 for each, compared to bleeding without taking NSAIDs). Overall, 74% of patients with upper gastrointestinal hemorrhage from peptic ulcer were taking NSAIDs. The prevalence of H. pylori infection was similar among the ulcer patients presenting with and without upper gastrointestinal tract bleeding. CONCLUSIONS: The location of a gastric ulcer on the greater curvature, and presentation with upper gastrointestinal tract bleeding, are separate and valuable clues to the involvement of NSAIDs. NSAID use may now be responsible for most bleeding complications of ulcer disease, regardless of H. pylori status.

Adult↗
PubMed1996

Detection of Helicobacter pylori in paraffin-embedded gastric biopsy specimens by in situ hybridization.

Helicobacter pylori is the causative agent of chronic gastritis, peptic ulcers, and is also associated with gastric cancer. Eradication of H pylori infection has proven to be difficult to confirm. The authors developed a nonradioactive in situ hybridization method for detection of H pylori and compared it with conventional methods for diagnosis of the infection. Reverse transcription followed by polymerase chain reaction (PCR) with two 22-base primers was used to amplify a 520 base pair (bp) segment of 16S rRNA from H pylori. The PCR product was labeled with digoxigenin and used as a probe. Specificity of the probe was tested by dot blot hybridization against DNA from 30 different strains of related and unrelated bacteria. Specificity of in situ hybridization assay was proven by the lack of hybridization on sections with gram negative and positive bacteria other than H pylori, with an unrelated probe, without probe, and after RNase treatment. A random sample of 15 biopsy specimens was blindly studied by in situ hybridization method and the results were compared with those of culture and conventional histology. Comparison of in situ hybridization and conventional histology showed agreement in all 15 specimens (5 negative and 10 positive). Between culture and in situ hybridization there was agreement in 13 cases (8 positive, 5 negative). Two cases were negative by culture but positive by in situ hybridization and histology. Nonradioactive in situ hybridization provides a sensitive and specific method for detection of H pylori infection. It should be particularly useful for confirmation of infection in cases equivocal with other methods, and potentially useful in post-treatment evaluation.

Base Sequence↗
PubMed1996

Disseminated herpesvirus infection during pregnancy.

A case of disseminated herpes simplex virus infection during pregnancy is reported, and 26 similar cases are reviewed. The present case was unusual in that it occurred in the 12th week of gestation, whereas all but one of the other cases occurred in the second or third trimester. This rare complication is generally preceded by a flu-like prodrome with or without oral or genital lesions. The clinical presentation is (1) encephalitis without hepatic involvement, (2) hepatitis with or without central nervous system findings, or (3) disseminated skin lesions. When the liver is involved, rapidly progressive hepatic necrosis and severe coagulopathy are common and the mortality is high. Early diagnosis and early institution of antiviral chemotherapy with acyclovir greatly improve the outcome for both mother and infant.

Adult↗
PubMed1996

Diagnosing and treating cytomegalovirus pneumonia in patients with AIDS.

Because cytomegalovirus (CMV) can be isolated from pulmonary secretions of human immunodeficiency virus (HIV)-infected patients without causing disease, its clinical significance as a cause of pneumonia in this patient population is frequently questioned. In a 22-month period, CMV pneumonia was diagnosed in 17 (8%) of 210 HIV-infected patients who underwent lung biopsy on the basis of microbiological and histologic criteria. The clinical presentations of these patients were nonspecific, including fever (100% of patients), shortness of breath (71%), cough (76%), and Pao2 of < 75 mm Hg (88%). A high correlation in the degree of viral burden in lung biopsy specimens was demonstrated by histologic examination, immunohistochemical analysis, and in situ hybridization. No other pulmonary pathogens were identified for nine patients, whereas other possible causes of pneumonia were present in eight: 11 patients had evidence of extrapulmonary CMV disease at presentation. Most patients initially responded to specific anti-CMV therapy; the overall mean survival +/- SD was 3.1 +/- 2.5 months. CMV should be considered as a possible cause of pneumonia in patients with advanced AIDS especially if CMV infection is documented at other sites.

AIDS-Related Opportunistic Infections↗