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Biomedical subjects

R A Cole

Publications and source records attributed to R A Cole.

At least 19 recordsLinked to original sources
PubMed1999

Influence of endoscopic biopsy forceps characteristics on tissue specimens: results of a prospective randomized study.

BACKGROUND: A large variety of endoscopic biopsy forceps are commercially available. However, little is known regarding the influence of forceps characteristics such as disposability, size, shape, and presence of a needle on the adequacy of the specimens for histologic diagnosis. Our aim was to analyze in a prospective, randomized, pathologist-blinded study the performance of different biopsy forceps. METHODS: Twelve biopsy forceps were tested, 6 each at upper endoscopy and colonoscopy. Two biopsy specimens were obtained with each forceps, for a total of 12 specimens per patient. The tissue samples were examined for the following parameters: weight (mg), size (mm3), depth, crush artifact, sheering effect, and adequacy of the specimens for histologic information (0 = inadequate, 1 = suboptimal, and 2 = adequate). RESULTS: Fifty-five patients undergoing routine upper or lower gastrointestinal endoscopy were included in the study, and a total of 624 tissue samples were available for analysis. Overall, disposable forceps provided specimens of greater size and depth. At upper endoscopy, alligator-shaped forceps improved the depth of the sample as did the absence of a needle within the cup. These factors, however, had no impact on the specimens obtained at colonoscopy. When the adequacy of the specimens was assessed for histologic diagnosis, no significant difference was noted between any of the individual forceps, although collectively oval-shaped forceps were superior to alligator-shaped forceps at colonoscopy. CONCLUSIONS: The biopsy forceps currently available in the market are equally efficient in providing histologic diagnosis. The primary consideration when selecting an endoscopic biopsy forceps, therefore, should be the cost and ease of use and not any perceived advantage in performance.

Adult↗
PubMed1999

Epizootic podoknemidokoptiasis in American robins.

Epizootics of scaly leg disease caused by infection with the submacroscopic mite Knemidokoptes jamaicensis (Acari: Knemidokoptidae) in migratory American robins (Turdus migratorius) from a residential area of Tulsa (Oklahoma, USA) are documented during the winters (December through February) of 1993-94 and 1994-95. Estimates of 60 to > 80% of the birds in several different flights arriving in the area had lesions consistent with knemidokoptic mange. Epizootic occurrence of K. jamaicensis also is confirmed incidentally in American robins from Georgia (USA) in 1995 and 1998 and in Florida (USA) in 1991. These are the first confirmed epizootics of scaly leg attributed to infections with mites specifically identified as K. jamaicensis in North America. Severity of observed lesions in American robins ranged from scaly hyperkeratosis of the feet and legs to extensive proliferative lesions with loss of digits or the entire foot in some birds. Histologically, there was severe diffuse hyperkeratosis of the epidermis which contained numerous mites and multifocal aggregates of degranulating to degenerating eosinophilic heterophils; there was mild to severe superficial dermatitis with aggregates of eosinophilic heterophils and some mononuclear cells. Based on limited data from affected captive birds in Florida, we questioned the efficacy of ivermectin as an effective acaricide for knemidokoptiasis and propose that conditions associated with captivity may exacerbate transmission of this mite among caged birds. While knemidokoptic mange apparently can result in substantial host morbidity and possibly mortality, the ultimate impact of these epizootics on American robin populations presently is unknown.

Animals↗
PubMed1997

Endoscopic variceal ligation is superior to combined ligation and sclerotherapy for esophageal varices: a multicenter prospective randomized trial.

Patients who have bled from varices remain at risk for rebleeding. There is interest in methods that would enable rapid eradication of varices. The present trial was designed to study whether combining ligation with sclerotherapy will allow quicker eradication of varices than either modality alone. Patients with bleeding esophageal varices were randomized into ligation or combination therapy groups. Patients in the ligation group were treated with endoscopic rubber band ligation alone. In combination group patients, each variceal column was ligated distally and 1 mL of ethanolamine was injected proximal to each ligated site. Subsequent treatment sessions were at 7- to 14-day intervals until varices were eradicated. The clinical and endoscopic characteristics of 25 patients in the ligation group were similar to those of 22 patients in the combination group. Follow-up was up to 30 months. Active bleeding was controlled in 100% of patients in the ligation group and 75% of those in combination group (P = NS). It took 3.3 +/- .4 (range, 1-7) sessions to eradicate varices with ligation and 4.1 +/- .6 (1-7) with combination therapy (P = NS). Survival (four deaths in ligation group, 8 in combination group), rebleeding rate (25% vs. 36%), and varix recurrence (16% vs. 23%) also were similar. There were more complications with combination therapy, including deep ulcers (65% vs. 20%; P < .05); dysphagia (30% vs. 0%; P < .05), with three strictures requiring dilation; and pain (30% vs. 10%; P = NS). Our results show that sclerotherapy combined with ligation offers no benefit over ligation alone. The higher complication rate with combination therapy does not warrant this approach.

Adult↗
PubMed1997

An objective end point for dilation improves outcome of peptic esophageal strictures: a prospective randomized trial.

BACKGROUND: The usual end point for defining success of dilation is subjective (relief of dysphagia). In most patents thus managed strictures recur. We asked whether an objective end point would improve outcome. METHODS: After dilation to 15 mm, patients were randomized into subjective and objective groups. In subjective group patients, end point for dilation was alleviation of dysphagia; in objective group patients, passing the 12 mm barium pill test. Objective group patients who failed underwent redilation until they passed the pill or failed three times. During Part 1 of the study, patients received ranitidine, during Part 2 they received omeprazole. RESULTS: In part 1, dysphagia was alleviated in 7 of 8 subjective group patients. Only 2 of 10 objective group patients passed the pill test and no additional patients passed after 3 sessions, although most had no dysphagia. In Part 2, 19 subjective groups and 15 objective group patients were studied. End point was not achieved in 3 objective group patients. Over long-term follow-up, objective group patients had less recurrent dysphagia (p = 0.02) and required fewer redilation sessions (p < 0.05). Overall, the pill test correlated with the presence or absence of dysphagia (P < 0.001). Predictive value of passing the pill 1 week after dilation for the absence of dysphagia was 100%, but of failing the pill test and the presence of dysphagia was only 18%. CONCLUSIONS: Achieving an objective end point reduces stricture recurrence and the need for subsequent dilation. Initial subjective improvement does not predict long-term success.

Adult↗
PubMed1997

New records of subcutaneous mites (Acari:Hypoderatidae) in birds, with examples of potential host colonization events.

New host, geographic records, or both are established for 14 species of hypoderatid deutonymphs from 14 species of birds in North America. Ten of these records are regarded as examples of a potential host colonization event where these hypopi have become established in hosts other than those with which they are normally associated. Herein, potential host colonization events by hypoderatid deutonymphs are regarded as more of an ecologically determined than physiologically specific phenomenon, often specifically related to sharing of nesting sites in the same rookeries by different host taxa. Neottialges ibisicola Young & Pence is placed as a junior synonym of Neottialges plegadicola Fain. The taxonomic status of Hypodectes propus from columbid versus ardeid hosts needs further study.

Animals↗
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↗
PubMed1997

Acanthocephala of the bald eagle (Haliaeetus leucocephalus) in North America.

Examination of bald eagles (Haliaeetus leucocephalus) collected from several locations in North America contributed new information concerning the acanthocephalan fauna of this host. Representatives of Arythmorhynchus brevis, representing a new host record, were collected from eagles in Florida, New Hampshire, and Wisconsin. Plagiorhynchus sp. was collected from an eagle in Florida. Corynosoma strumosum was collected from an eagle in Alaska. Andracantha phalacrocoracis, representing a new host record, was collected from an eagle in Alaska. Southwellina hispida, representing a new host record, was collected from eagles in Maine and Virginia. The occurrence of gravid or mature females of A. brevis, Plagiorhynchus sp., and S. hispida suggests that the bald eagle may serve as a competent definitive host for these species.

Acanthocephala↗
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

Clinical evaluation of a rapid immunochromatographic assay based on the 38 kDa antigen of Mycobacterium tuberculosis on patients with pulmonary tuberculosis in China.

SETTING: A rapid membrane-based antibody assay capable of diagnosing pulmonary tuberculosis within 15 min has been developed using the 38 kDa antigen from Mycobacterium tuberculosis. OBJECTIVE: To determine the specificity and sensitivity of this assay and evaluate its usefulness in a clinical setting. DESIGN: Sera from patients with active pulmonary tuberculosis were obtained from three hospitals in China. The control groups consisted of patients who were diagnosed with lung diseases other than tuberculosis and healthy subjects. RESULTS: Antibody was detected in 54 of 61 (89%) sputum positive patients and 67 of 91 (74%) sputum negative patients who had been clinically diagnosed as having active pulmonary tuberculosis. Five out of 56 (9%) patients with respiratory diseases other than tuberculosis and 1 out of 30 (3%) healthy controls had a positive antibody response. The overall specificity of the assay was 93% and the positive predictive value was 95%. We conclude that this assay is rapid, sensitive and specific and will be a valuable aid in the clinical diagnosis of pulmonary tuberculosis.

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

Endoscopic retreatment after successful initial hemostasis prevents ulcer rebleeding: a prospective randomized trial.

BACKGROUND AND STUDY AIMS: Rebleeding after initial endoscopic hemostasis remains an important determinant of poor prognosis in patients with ulcer hemorrhage. Prospective identification of patients who are at high risk for rebleeding, and directing further therapeutic measures in these patients, would be expected to improve the prognosis. PATIENTS AND METHODS: We used our previously described scoring system (the Baylor Bleeding Score) to identify patients at increased risk for rebleeding after initially successful endoscopic hemostasis, and randomized them into retreatment and no-retreatment groups. Patients in the retreatment group received additional endoscopic heat probe therapy at 24 hours, the follow-up was otherwise similar. Forty men with major ulcer hemorrhage were randomized, 19 to the retreatment group and 21 to the no-retreatment group. Patients in the two groups had similar Baylor Bleeding Scores, blood transfusion needs (median three vs. two units), ulcer sites (duodenal 57% vs. 43%), stigmata of hemorrhage (actively bleeding 68% vs 67%), and received similar initial endoscopic therapy (heat probe 240 J vs. 300 J). Patients in the retreatment group received additional heat probe therapy (median 165 J) at 24 hours. RESULTS: Rebleeding, requiring significantly more blood transfusion, occurred in 24% of the no-retreatment group patients compared to none of the retreatment group patients (p < 0.05). CONCLUSIONS: Endoscopic retreatment after successful initial endoscopic hemostasis prevents rebleeding in highrisk patients with ulcer bleeding.

Adult↗
PubMed1996

Resolution of a metaplastic duodenal polyp after cure of Helicobacter pylori infection.

Although there have been several reports of hyperplastic gastric polyps associated with persistent Helicobacter pylori gastritis, the association of H. pylori infection with metaplastic polyps in the duodenum has not hitherto been described. After a 52-year-old man had a single episode of hematemesis, endoscopy showed a smooth polyp 1 cm in greatest dimension formed by a proliferation of gastric epithelial cells of fundic and antral type found in the duodenal bulb. The outer surface was entirely covered with a single layer of hyperplastic columnar epithelium with many H. pylori organisms. After administration of metronidazole 500 mg, omeprazole 20 mg for 4 weeks, and clarithromycin 250 mg twice a day for 2 weeks, endoscopy showed a decrease in size of the duodenal polyp. At 12 weeks there was complete regression of the polyp. This report documents a new and unusual finding: resolution of a gastric metaplastic polyp in the duodenum associated with cure of H. pylori.

Anti-Bacterial Agents↗
PubMed1996

Metronidazole, ranitidine and clarithromycin combination for treatment of Helicobacter pylori infection (modified Bazzoli's triple therapy).

BACKGROUND: Multi-drug regimens are generally required to reliably cure Helicobacter pylori infection. Metronidazole, clarithromycin and omeprazole has proven to be an effective combination therapy with a cure rate of 90% or greater. METHODS: We evaluated a 14-day combination regimen for H.pylori infection consisting of metronidazole 500 mg b.d., clarithromycin 250 mg b.d. and ranitidine 300 mg b.d. (MRC) instead of omeprazole. Ranitidine alone was continued for an additional 4 weeks. H. pylori status was determined by rapid urease testing, histopathology using the Genta stain, and by culture at entry and 4 weeks after completing antimicrobial therapy. RESULTS: Twenty-seven patients with documented peptic ulcer disease and H. pylori infection were treated. Five had previously failed macrolide-based antimicrobial therapy; none had received metronidazole. All ulcers were healed at week 6 except one patient taking naproxen; his H. pylori infection was cured. Overall, H. pylori infection was cured in 78% (95% CI = 58-91%). In patients with clarithromycin-sensitive isolates, the cure rate was 20 of 23 (87%, 95% C.I. = 66-97%); only one of four patients (25%) with clarithromycin-resistant isolates was cured. In contrast, four of five patients with metronidazole-resistant isolates were cured (80%). In patients with isolates sensitive to both antibiotics, the cure rate was 16 of 18 (89%, 95% C.I. = 65-99%). Mild side effects were reported by 27%, including diarrhoea and altered taste. Compliance averaged 98%. CONCLUSION: These results suggest that the combination of metronidazole, ranitidine and clarithromycin results in high cure rates in patients with clarithromycin-sensitive isolates. Omeprazole may not be required for Bazzoli's triple therapy; and large multicentre comparative trials are indicated.

Adult↗
PubMed1996

Detection of pulmonary and extrapulmonary tuberculosis patients with the 38-kilodalton antigen from Mycobacterium tuberculosis in a rapid membrane-based assay.

A rapid membrane-based serologic assay using the 38-kDa antigen from Mycobacterium tuberculosis for the diagnosis of tuberculosis (TB) was evaluated with 201 patients with pulmonary TB, 67 patients with extrapulmonary TB, 79 Mycobacterium bovis BCG-vaccinated healthy controls, and 77 non-TB respiratory patients. The overall sensitivities, specificities, and positive and negative predictive values were, respectively, 92, 92, 84, and 96% for sputum-positive TB patients; 70, 92, 87, and 79% for sputum-negative TB patients; and 76, 92, 80, and 90% for extrapulmonary-TB patients. Only 2% (1 of 44) of the healthy control BCG-vaccinated subjects gave weak positive signals in the assay, indicating that this rapid serological assay is a valuable aid in clinical diagnosis for both pulmonary and extrapulmonary TB.

Adolescent↗
PubMed1996

An O-antigen processing function for Wzx (RfbX): a promising candidate for O-unit flippase.

O antigen is the major cell surface antigen of gram-negative bacteria, and the genes responsible for its synthesis are located in a single gene cluster. The wzx (rbfX) gene, which is characteristic of the major class of O-antigen gene clusters, encodes a hydrophobic protein with 12 potential transmembrane segments. We demonstrate that a wzx mutant accumulates undecaprenol pyrophosphate-linked O units which appear to be on the cytoplasmic side of the cytoplasmic membrane, suggesting that the wzx gene encodes a flippase for O-unit translocation across that membrane.

Bacterial Proteins↗
PubMed1995

Dictyostelium discoideum mitochondrial DNA encodes a NADH:ubiquinone oxidoreductase subunit which is nuclear encoded in other eukaryotes.

Complex I, a key component of the mitochondrial electron transport system, is thought to have evolved from at least two separate enzyme systems prior to the evolution of mitochondria from a bacterial endosymbiont, but the genes for one of the enzyme systems are thought to have subsequently been transferred to the nuclear DNA. We demonstrated that the cellular slime mold Dictyostelium discoideum retains the ancestral characteristic of having mitochondria encoding at least one gene (80-kDa subunit) that is nuclear encoded in other eukaryotes. This is consistent with the cellular slime molds of the family Dictyosteliaceae having diverged from other eukaryotes at an early stage prior to the loss of the mitochondrial gene in the lineage giving rise to plants and animals. The D. discoideum mitochondrially encoded 80-kDa subunit of complex I exhibits a twofold-higher mutation rate compared with the homologous chromosomal gene in other eukaryotes, making it the most divergent eukaryotic form of this protein.

Animals↗
PubMed1995

Prospective validation of the Baylor bleeding score for predicting the likelihood of rebleeding after endoscopic hemostasis of peptic ulcers.

Endoscopic therapy is effective in securing hemostasis for bleeding ulcers, but bleeding recurs in 10% to 30% of patients. Prospective identification of patients at increased risk for rebleeding is requisite to reducing rebleeding rates. We previously developed a three-component scoring system that identifies patients at increased risk for rebleeding. In the present study, we prospectively validated our scoring system. Forty-seven men ranging in age from 23 to 95 years in whom endoscopic therapy for bleeding ulcers was successful were studied. Patients with pre-endoscopy scores greater than 5 or postendoscopy scores greater than 10 were stratified as high-risk, and patients with pre-endoscopy scores of 5 or less and post-endoscopy scores of 10 or less as low-risk. Twenty-six patients were categorized as high-risk and 19 as low-risk. All patients were followed until discharged from the hospital. The rebleeding rate for high-risk patients was 31% (8 of 26), compared with 0 for low-risk patients (p < .05). We conclude that our scoring system accurately predicts patients at increased risk for rebleeding after successful endoscopic therapy of bleeding ulcers.

Adult↗