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Biomedical subjects

D Y Graham

Publications and source records attributed to D Y Graham.

At least 415 records · Page 23Linked to original sources

Factors influencing the epidemiology of Helicobacter pylori infection in children.

The epidemiology of Helicobacter pylori infection was studied in 245 healthy children (between 3 and 20 years of age) who presented for day surgery at Arkansas Children's Hospital. H pylori infection was identified serologically using an enzyme-linked immunosorbent assay to detect the presence of IgG against the high molecular weight, cell-associated antigens of H pylori. Demographic information collected included age, gender, race, family income, type of housing, location of housing, water supply, health status, upper gastrointestinal symptoms, and keeping pets. One hundred eighty-nine white children and 56 black children were studied; 139 were boys and 106 were girls. The data were analyzed by logistic regression analysis. H pylori infection increased significantly with age (P less than .05). The frequency of H pylori infection was higher in blacks than whites (P less than .01), and this difference remained after adjusting for age, gender, and family income. Family income was used as a measure of socioeconomic class and was an important factor related to infection; the rate of acquisition of H pylori in those children with family income less than +5000/year was twice that of those with incomes greater than +75,000/year (P less than .001). There were no significant differences in H pylori infection related to gender, type of housing, location of housing, or source of water supply. It is concluded that the rate of acquisition of H pylori infection increases with age, is higher in blacks than whites, and is inversely related to socioeconomic class.

Adolescent↗

Simple noninvasive method to test efficacy of drugs in the eradication of Helicobacter pylori infection: the example of combined bismuth subsalicylate and nitrofurantoin.

Eradication of Helicobacter pylori infections has proved to be difficult. There is a need both for improved therapies and for ways to rapidly identify therapies that show sufficient promise to be worth pursuing. The objectives of this study were to evaluate the value of a therapeutic regimen of a bismuth salt plus nitrofurantoin for eradication of infection by H. pylori and to determine the validity/utility of the urea breath test in monitoring the progress of a clinical trial. We used an 80% eradication rule to define a promising therapeutic regimen, i.e., a regimen that eradicated the infection (no evidence of infection by H. pylori 4 wk after termination of therapy) in at least 80% of the individuals treated. Eighteen men (median age 38) with documented infection by H. pylori completed the study. At the end-of-study evaluation, H. pylori infection was eradicated (negative urea breath test, culture, and histology) in only one of 18 (5.5%) subjects; 15 were positive by the urea breath test, 16 by culture, 15 by Warthin-Starry stain, and 16 by the presence of acute-on-chronic inflammation. Using the 80% eradication rule, any one of these tests alone would have identified that the combination of antimicrobials tested was not effective in the eradication of the infection. We conclude that the urea breath test is a simple, noninvasive, cost-effective method to separate promising from unpromising candidate therapies and for the evaluation of new therapeutic concepts.

Adult↗

Effect of Helicobacter pylori infection on the severity of gastroduodenal mucosal injury after the acute administration of naproxen or aspirin to normal volunteers.

This study asked whether Helicobactor pylori infection accentuated the severity of NSAID-induced mucosal injury of the stomach or duodenum. We evaluated the severity of acute mucosal injury and H. pylori status in 61 normal volunteers (ages 22-43 yr) receiving naproxen (1000 mg, n = 30) or aspirin (3900 mg, n = 31) daily for 7 days. NSAID-induced gastric and duodenal mucosa each were endoscopically graded separately for hemorrhages and erosions-ulcers on a scale of 0 to 4. H. pylori infection was identified by a sensitive and specific ELISA. Nine of the 30 subjects in the naproxen group and 12 of the 31 subjects in the aspirin group were H. pylori positive (p = NS). There was no statistically significant difference between the frequency of mucosal hemorrhage in those with and those without H. pylori infection (44% compared with 33% for those receiving naproxen and 90% of those receiving ASA, p = NS for each). There were also no differences in the frequency or severity of erosive mucosal injury seen, e.g., acute ulcers were found in 16.5% and 17.5% of infected and uninfected subjects, respectively. We conclude that the presence of H. pylori infection does not influence the degree or type of mucosal damage associated with the acute administration of naproxen or aspirin.

Adult↗

13C-bicarbonate breath test as a measure of gastric emptying.

Radionuclide studies are widely used to estimate the gastric emptying rate of solids and liquids. Unfortunately, these methods carry the risk of radiation exposure and require expensive and complex equipment. Carbon-13, a stable, nonradioactive isotope, has been used successfully as a marker in the gastrointestinal tract for other purposes. A preliminary study using ingested NaH13CO3 and measuring 13CO2 breath excretion suggested that this test might be a simple, noninvasive, and inexpensive method for determining gastric emptying. To determine the efficacy of NaH13CO3 as a noninvasive marker for gastric emptying, the resulting 13CO2 breath excretion was determined simultaneously with standard radiolabeled meal measurements of gastric emptying of liquids and solids in 15 patients. 13CO2 breath excretion did not correlate with the gastric emptying of either solids or liquids, as determined by radionuclide techniques. These results suggest that NaH13CO3 is not a reliable indicator of gastric emptying. Factors other than gastric emptying may affect the rate of 13CO2 absorption and exhalation, rendering it unreliable as a measure of gastric emptying.

Adult↗

Norwalk virus genome cloning and characterization.

Major epidemic outbreaks of acute gastroenteritis result from infections with Norwalk or Norwalk-like viruses. Virus purified from stool specimens of volunteers experimentally infected with Norwalk virus was used to construct recombinant complementary DNA (cDNA) and derive clones representing most of the viral genome. The specificity of the clones was shown by their hybridization with post- (but not pre-) infection stool samples from volunteers infected with Norwalk virus and with purified Norwalk virus. A correlation was observed between the appearance of hybridization signals in stool samples and clinical symptoms of acute gastroenteritis in volunteers. Hybridization assays between overlapping clones, restriction enzyme analyses, and partial nucleotide sequence information of the clones indicated that Norwalk virus contains a single-stranded RNA genome of positive sense, with a polyadenylated tail at the 3' end and a size of at least 7.5 kilobases. A consensus amino acid sequence motif typical of viral RNA-dependent RNA polymerases was identified in one of the Norwalk virus clones. The availability of Norwalk-specific cDNA and the new sequence information of the viral genome should permit the development of sensitive diagnostic assays and studies of the molecular biology of the virus.

Amino Acid Sequence↗

The use of gastric salvage cytology in the diagnosis of malignancy: a review of 731 cases.

Over an 8-yr period at the Houston Veterans Hospital, 731 endoscopic gastric salvage cytologies were performed in 671 patients, with surgical biopsy also done in 660. Seventy-six patients subsequently had tissue biopsy-proven or resection-proven malignancies. Salvage cytology had a sensitivity of 91% and a specificity of 100% for the detection of primary adenocarcinoma. Biopsy alone had a sensitivity of 92%; endoscopic gastric salvage cytology and surgical biopsy combined had a sensitivity of 100% in both primary and metastatic neoplasms. This study shows that the combination of endoscopic biopsy and salvage cytology increases the diagnostic accuracy for gastric carcinoma. Gastric salvage cytology requires minimal disruption of the routine endoscopic procedure and is therefore an easier and more rapid cytologic technique than gastric brushing cytology.

Adenocarcinoma↗

What happens to tablets and capsules in the stomach: endoscopic comparison of disintegration and dispersion characteristics of two microencapsulated potassium formulations.

Previously we investigated gastric emptying and distribution of a capsule formulation of microencapsulated KCl and found the drug was usually present in clumps of KCl crystals held in place by gastric mucus. We therefore investigated whether a tablet formulation of microencapsulated KCl would have improved dispersion. We characterized the intragastric disintegration of capsules and tablets of microencapsulated KCl in 12 subjects. The capsule formulation floated in the gastric pool; one end would adhere to the gastric mucosa and the motion of the tethered capsule would pull the end of the capsule off. The KCl crystals would then be deposited in a mass. In contrast, the tablet formulation sank to the anatomically most dependent portion of the stomach. The tablet rapidly became soft and fragile but, if allowed to remain in one place and minimally disturbed, required a median of 12 min to lose its shape. If allowed to reach the gastric antrum, the tablet was quickly ground by the antro-pyloric pump and widely dispersed. Once liberated in the stomach, the microencapsulated KCl crystals were bound into a more-or-less cohesive mass. The differences between KCl formulations, once the crystals were released, was minimal although the larger crystals from the tablet formulation appeared less adherent and cohesive; they dispersed more in a reticulated pattern when the stomach was distended. We conclude that formulation of a drug in a microencapsulated multiple-unit dosage form does not guarantee wide dispersion nor absence of high local concentration of drug.

Adult↗

Diagnosis of metastatic lesions to the stomach by salvage cytology. A report of three cases.

Secondary neoplasms of the stomach are rare and are often clinical and diagnostic problems. Three patients with bleeding "volcano-like" ulcers were diagnosed by combined endoscopic "salvage" cytology and surgical biopsy as having metastatic submucosal lesions from hematologic spread. The combination of endoscopic appearance, clinical findings, and tissue and cytologic examination can lead to the correct diagnosis. The results from these cases support the utility of this cytologic technique in combination with biopsy in this clinical setting.

Aged↗

Omeprazole versus placebo in duodenal ulcer healing. The United States experience.

The study objective was to study the ulcer healing effects and safety of the proton pump inhibitor, omeprazole, given in a dose of 20 mg once daily before breakfast. The study design was a randomized, double-blind, multicenter comparison of omeprazole and placebo using endoscopy to assess ulcer healing after two or four weeks of therapy. One hundred fifty-three patients with endoscopically documented active duodenal ulcer were studied. One hundred two patients received omeprazole and 51 received placebo. Patients in both groups were similar with regard to age, sex, duration of disease, initial ulcer size, smoking history, and alcohol use. A "per protocol" analysis of healing rates showed a significant advantage for omeprazole (P less than 0.01) at both week 2 (41% vs 13%) and week 4 (75% vs 27%). Concomitant factors (including smoking and ulcer size) did not alter the significance of the differences in healing rates between omeprazole and placebo. Complete relief of day and night pain was more often achieved (P less than 0.01) in the omeprazole group. "All-patients treated" analyses for healing and pain relief gave results similar to the respective "per protocol" analyses. Omeprazole was well tolerated; fewer patients had clinical and laboratory adverse experiences in the omeprazole group than in the placebo group. Fasting serum gastrin levels increased with omeprazole therapy (mean 34.9 to 73.5 pg/ml) but exceeded the normal range (greater than 150 pg/ml) in only 12.3% of patients. Two weeks after therapy was stopped, serum gastrin levels showed a decrease toward baseline but had not yet completely returned to pretreatment levels (mean 49.7 pg/ml).(ABSTRACT TRUNCATED AT 250 WORDS)

Double-Blind Method↗

Antimony electrodes. Mucosal potential differences and buffer composition adversely affect pH measurements in the stomach.

Antimony electrodes are clinically useful because of their low cost and simple construction; they have no glass to break. There is only a few hundred ohms resistance between an antimony pH electrode and the reference electrode so that the voltage generated can be recorded with simple low-impedance recorders linked to microcomputers. We used antimony pH electrodes with silver-silver chloride electrodes applied to the skin to measure the gastric pH in vivo and obtained erroneously high values. Using an ion-permeable dialysis chamber to surround electrodes in vivo, we showed that the discrepancy was caused by interference from gastric transmucosal potential difference. To circumvent the interference, we used a combination electrode constructed by embedding a monocrystalline antimony electrode and a silver-silver chloride reference electrode in dental acrylic. Antimony pH electrodes calibrated with commercial pH buffers also gave erroneous readings in HCl solutions of known pH. The erroneous readings were due, in part, to organic complex-forming ligands or organic salts such as potassium phthalate present in commercial buffer solutions. Accurate pH calibration can be obtained with citrate or acetate buffers or by using a normogram to correct for the errors introduced with commercial buffers. The combination antimony pH electrode has a number of potential clinical and research applications and simplifies obtaining accurate and reliable pH data in vivo.

Antimony↗

Endoscopic comparison of cimetidine and sucralfate for prevention of naproxen-induced acute gastroduodenal injury. Effect of scoring method.

Nonsteroidal antiinflammatory drug-induced gastroduodenal mucosal damage observed endoscopically is usually categorized as hemorrhages, erosions, or ulcerations. We undertook this study to determine whether the injury produced by a commonly prescribed NSAID, naproxen, could be reduced by cotherapy with sucralfate or cimetidine and to determine how dependent the differences in the degree of protection against mucosal injury measured were on the scoring system used. Four groups of 20 healthy volunteers with endoscopically normal gastric and duodenal mucosa received naproxen (500 mg twice a day) plus cimetidine (300 mg four times a day or 400 mg twice a day), sucralfate (1 g four times a day), or placebo for seven days. After seven days of therapy, a second endoscopy was performed. Separate scoring systems were used for the presence of hemorrhages, erosions, and a combination of both types of injury. There were significantly fewer mucosal hemorrhages present when naproxen and cimetidine were administered than when naproxen was administered with placebo or sucralfate (placebo vs 300 mg cimetidine, P = 0.04, and placebo vs 400 mg cimetidine, P = 0.006, placebo vs sucralfate, P = 0.26). Both cimetidine dosages resulted in significantly fewer hemorrhages than were present following cotherapy of naproxen and sucralfate (P less than 0.05). In contrast, there was no discernible difference in the mucosal injury between placebo and any drug or between any two active therapies when the injury was evaluated based on the presence of gastric erosions.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

A new endoscopic method for managing food impaction in the esophagus.

Previously described methods for dealing with acute food impaction in the esophagus are not uniformly efficacious, are cumbersome, and often prove dangerous. This paper describes a new technique using an endoscope which is modified such that the endoscope itself becomes a direct-vision suction device. We have successfully used the technique in seven patients with meat bolus impaction in the esophagus. The method proved quick and safe, and no complications occurred. After relieving the impaction an adequate diagnostic examination was done in all patients. In four patients with a predisposing peptic stricture and one with Schatzki's ring, treatment of the lesion was possible during the same endoscopic session.

Adult↗

Unsaturated fatty acids and viability of Helicobacter (Campylobacter) pylori.

Helicobacter (Campylobacter) pylori was found to be sensitive to the toxic effects of an unsaturated fatty acid (arachidonic acid). Data are presented that support the hypothesis that exogenous catalase added to basal media enhances the growth of H. pylori by preventing the formation of toxic peroxidation products from long-chain unsaturated fatty acids.

Arachidonic Acid↗

Inappropriate hypergastrinaemia in asymptomatic healthy subjects infected with Helicobacter pylori.

An ELISA test determined serologically that eight of 95 apparently healthy men (aged 19-26 years) had an asymptomatic infection with Helicobacter pylori at the time of simultaneous measurement of 24 hour intragastric acidity and 24 hour plasma gastrin concentration. There was no significant difference in the median integrated 24 hour intragastric acidity between the H. pylori positive and H. pylori negative subjects (688 and 842 mmol/h/l; p = 0.271, respectively), whereas the median integrated 24 hour plasma gastrin concentration was significantly higher in the H pylori positive than in the H pylori negative subjects (389 and 198 pmol/h/l; p less than 0.001). Longterm hypergastrinaemia, associated with persistent H pylori infection, could be a cause of the increased parietal cell mass that is considered characteristic of duodenal ulcer patients.

Adult↗

The relationship between nonsteroidal anti-inflammatory drug use and peptic ulcer disease.

It has become increasingly recognized that nonsteroidal anti-inflammatory drug (NSAID) use is associated with serious gastroduodenal mucosal injury that can eventuate in upper gastrointestinal bleeding or perforation. This article discusses the lack of predictive value of studies administering NSAIDs to normal volunteers. The new data concerning prevention and treatment of chronic NSAID ulcers is also discussed.

Anti-Inflammatory Agents, Non-Steroidal↗