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Biomedical subjects

A P Morgan

Publications and source records attributed to A P Morgan.

At least 19 recordsLinked to original sources
PubMed1998

Regulatory control of veterinary diagnostic test kits.

Veterinary diagnostic test kits are used in clinical practice and production medicine as a basis for prescribing vaccination and/or treatment regimens. These kits are also used by state and federal animal health officials to control or regulate the movement of animals. The regulation of such kits, which generally takes the form of establishing requirements for licensure, ensures that the kits conform to minimum standards for sensitivity, specificity and reproducibility. To qualify for licensing, diagnostic test kits should have consistent performance characteristics.

Animals↗
PubMed1997

Teen father participation in child rearing: family perspectives.

OBJECTIVES: To explore adolescent fatherhood from the perspectives of teen fathers, teen mothers, paternal grandmothers (PGMs), and maternal grandmothers (MGMs). To identify perceived barriers to and recommendations for the enhancement of teen father participation in child rearing. METHODS: A total of 61 teen parents participated in the design of a structured interview. A community-based sample of 173 teen fathers, 167 teen mothers, 76 PGMs, and 79 MGMs were interviewed by teenage assistants. Multiple logistic regression analysis using maximum likelihood estimation and the best subset algorithm identified barriers most predictive of paternal uninvolvement in child rearing. RESULTS: Fifty-four percent of teen fathers and 70% of partners of teen mothers' met the definition of involvement in child rearing. Disinterest in child rearing most consistently predicted uninvolvement. Fathers were less likely than mothers to report paternal disinterest as a barrier and more likely to attribute their lack of involvement to resistance from mothers and MGMs (p < 0.05). The best model predicting paternal involvement from the fathers' perspective included paternal disinterest [odds ration (OR) = 0.42, confidence interval (CI) = 0.19-0.92] and age (OR = 0.74, CI = 0.56-0.97). The best model from the mothers' perspective included paternal disinterest (OR = 0.16, CI = 0.07-0.36) and lack of time (OR = 0.31, CI = 0.15-0.91). Of those fathers who cited disinterest, there was an association with lack of money (p = 0.002) and lack of knowledge of child care (p = 0.069. While fathers and mothers disagreed on several interventions, they agreed (82% and 95%, respectively) that availability of jobs would promote paternal involvement. CONCLUSIONS: Most teen fathers in this study were involved and interested in child rearing. A young father's financial insecurity or confusion about child care was most likely to lead to a stated disinterest, and that disinterest predicted uninvolvement.

Adolescent↗
PubMed1993

Design and analysis of veterinary vaccine efficacy trials.

Vaccination-challenge tests that involve all-or-none responses and do not require a direct comparison between vaccinates and controls can be completely characterized by the binomial distribution. Consumer and producer risks associated with binomial distribution based tests can be adjusted by altering the number of animals involved and the criterion for acceptance. Clinical signs or other outcomes measured on an ordinal or ranking scale should generally be analyzed by nonparametric statistical procedures. Parametric statistical tests are the most appropriate for data measured on an interval scale if the necessary assumptions are met concerning the population sampled. The use of in vitro potency tests in quality control procedures for inactivated vaccines depends on the demonstration of a significant dose-response efficacy relationship in the host animal.

Analysis of Variance↗
PubMed1993

Verapamil enhances doxorubicin activity in cultured human renal carcinoma cells.

Cells from 22 renal cell carcinomas (RCC) were established in culture. Sensitivity of the tumour cells to doxorubicin alone and in combination with racemic verapamil, which reverses multidrug resistance, was tested using a [75Se]selenomethionine uptake assay to measure protein synthesis. The effect of verapamil was expressed as a potentiation index: LD50doxorubicin/LD50doxorubicin + verapamil. The potentiation index in 15 of these carcinomas was determined for cells within the first 14 days of culture. At 3.3 mumol/l concentration of verapamil, of the tumours sensitive to doxorubicin alone (LD50 < 0.75 microgram/ml) five of seven showed a potentiation index of > 2. For the less sensitive tumours the analogous proportion was seven of eight. Tumour cell expression of glycoprotein P-170, associated with multidrug resistance, was estimated using the monoclonal antibody C-219. Initial expression levels were unrelated to the action of verapamil. In five tumours the proportion of cells expressing P-170 declined as the period of culture increased. This was not associated with any consistent change in the LD50 for doxorubicin or in potentiation of doxorubicin sensitivity by verapamil. Cell cloning associated with prolonged cell growth in vitro could mimic tumour cell cloning which accompanies the formation of metastases. Thus reduced expression of P-170 on prolonged cell growth in vitro may be a pointer to the efficacy of combination therapy in the treatment of patients with metastatic renal cell carcinoma.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1991

Composition of gastro-oesophageal refluxate.

Fifty two patients with abnormal acid gastro-oesophageal reflux were studied by simultaneous oesophageal pH monitoring and continuous aspiration for 16 hours. Aspirates (from discrete two hour periods) were analysed for volume, pH, bile acids (conjugated and unconjugated), trypsin, and pepsin. The results were compared with pH changes and degree of oesophagitis. Patients with oesophagitis had greater acid reflux than those without, but patients with stricture and Barrett's oesophagus had similar acid reflux to those with uncomplicated erosive oesophagitis. Pepsin concentrations were highest in patients with stricture and Barrett's oesophagus particularly during nocturnal periods. Conjugated bile acids were detected in 75% of patients, mainly during the night, but only 2% of aspirates contained concentrations likely to be cytotoxic. Unconjugated bile acids were not detected, and trypsin was seldom found. Reflux oesophagitis is caused by acid and pepsin. Bile acids and trypsin are probably unimportant.

Adult↗
PubMed1990

The effect of verapamil on the anti-tumour action of mitozantrone and doxorubicin against renal carcinoma cells in vitro.

Ten renal carcinomas were established in culture and their sensitivity to mitozantrone +/- verapamil, as measured by (75Se) selenomethionine incorporation, was studied. The 5 tumours with spread beyond the kidney were those in which sensitivity to mitozantrone was enhanced by verapamil. With 4 of the 10 tumours and 1 further carcinoma, similar experiments were performed using doxorubicin. This drug was more active, its anti-tumour action being related to concentration. Verapamil was more effective in potentiation of doxorubicin and this action increased in proportion to the concentration of verapamil added.

Dose-Response Relationship, Drug↗
PubMed1990

New technique for analysing conjugated bile acids in gastric juice.

A new technique of high performance liquid chromatography (HPLC) was developed for the analysis of conjugated bile acids in gastric juice. The assay is rapid, sensitive, and highly specific for bile acid conjugates over the range 30-10,000 mumol/l and is not affected by the presence of food. Ten patients with a variety of common upper gastrointestinal disorders underwent continuous gastric aspiration for 16 hours, including a fasting, post-prandial, and nocturnal period, and aliquots of aspirates were analysed every two hours by the HPLC technique for the six most prevalent bile acid conjugates present in human hepatic bile. Intragastric bile acid concentrations were lowest in the post-prandial period and highest in the early hours of the morning. Conjugated bile acid proportions, or profiles, varied considerably from patient to patient, but tended to remain uniform over time in individual patients. It is concluded that HPLC is superior to enzymatic techniques for the analysis of conjugated bile acids in the upper gastrointestinal tract.

Adult↗
PubMed1988

Bile acid concentrations in the refluxate of patients with reflux oesophagitis.

Although reflux of bile acids has been implicated in the pathogenesis of reflux oesophagitis, attempts to document this in vivo have failed to detect more than trace amounts of bile acid in the oesophagus. To determine the bile acid composition of oesophageal refluxate, 45 patients with abnormal acid gastro-oesophageal reflux with oesophagitis and 10 controls had a size 14 Fr Salem sump tube positioned 5 cm above the lower oesophageal sphincter. Oesophageal contents were continuously aspirated and collected in aliquots every 2 h over 16 h. Fasting, postprandial, upright and supine (nocturnal) periods were assessed and total conjugated bile acids were measured by high pressure liquid chromatography with a sensitivity of 8 mumol/l. Conjugated bile acids were detected in 2 of 10 controls (maximum 40 mumol/l) and in 39 of 45 patients (87 per cent). Eleven patients had peak conjugated bile acid levels greater than 200 mumol/l, and these levels occurred exclusively during the supine (nocturnal) period. Median conjugated bile acid levels during daytime reflux were less than 20 mumol/l which was significantly lower than during nocturnal reflux (median 51 mumol/l, P less than 0.001). Conjugated bile acids are detected in the oesophagus of most patients with oesophagitis and may play a role in the pathogenesis of oesophagitis in some patients with nocturnal gastro-oesophageal reflux.

Adult↗
PubMed1986

Intragastric bile acids and scintigraphy in the assessment of duodenogastric reflux.

Following endoscopic gastric juice aspiration, intragastric bile acids were measured in 105 patients undergoing routine or review gastroscopy. Subsequently, duodenogastric reflux was assessed using 99mTc butyliminodiacetic acid (BIDA) scintigraphy and intragastric bile acid levels compared with the grades of reflux assessed scintigraphically. There was a significant correlation between both free and total intragastric bile acid levels and the degree of radiological bile reflux, especially when reflux was severe. Both endoscopic measurements of bile acids and BIDA scintigraphy appear to be useful methods for determining duodenogastric reflux, but neither may be accurate enough to quantify minor degrees of reflux.

Bile Acids and Salts↗
PubMed1986

Intragastric bile acids and histological changes in gastric mucosa.

Multiple gastric biopsies and gastric juice aspirates were taken in 108 patients undergoing routine or review gastroscopy for a variety of upper gastrointestinal disorders. The gastric juice was measured for free and total bile acids and the biopsies examined for premalignant mucosal changes. Total bile acid levels were significantly higher in patients with atrophic gastritis, intestinal metaplasia and dysplasia but not chronic gastritis. There was no correlation between the severity of the dysplasia and total bile acid levels. Free bile acid levels were significantly higher in patients with atrophic gastritis but not in patients with chronic gastritis, intestinal metaplasia or dysplasia. These results suggest that intragastric bile acids may be implicated in premalignant histological changes of gastric mucosa and thus play a part in gastric carcinogenesis.

Atrophy↗
PubMed1980

Femoral triangle sepsis in dialysis patients: frequency, management, and outcome.

Prosthetic devices for dialysis access sometimes have to be implanted in the groin. Infections are frequent there, and when they occur their management is influenced by the patients' need for continued dialysis, and often, by the presence of concomitant diseases. We report implantation of 161 dialysis access devices of various types, all utilizing the femoral vessels. Twenty-seven femoral triangle injections eventually occurred. Both the approach to their treatment and outcome were influenced by mode of presentation, localized infection being most favorable, and fever without localized signs least. The compromise surgical procedures made necessary by the patients' precarious medical status were successful in most instances but overall mortality was 18%, and the amputation rate 22%.

Arteriovenous Shunt, Surgical↗
PubMed1978

Endocarditis with the indwelling balloon-tipped pulmonary artery catheter in burn patients.

The postmortem finding of acute right-sided bacterial endocarditis in a burn patient monitored with an indwelling pulmonary artery (Swan-Ganz) catheter for 14 days prompted a review of burn autopsies in which the catheter had been used. Autopsies of six consecutive burn patients monitored with a pulmonary artery catheter and who then died showed septic or aseptic endocarditis. In two of the six patients, right-sided staphylococcal endocarditis was the anatomic cause of death. In the remaining four, the lesions were aseptic thrombotic vegetations involving primarily the right atrium, tricuspid valve, right ventricle, and pulmonic valve. Several factors in the severely burned patient would favor endocarditis where a foreign object impacts on the heart valves. These include intermittent bacteremia, hypercoagulability, hyperdynamic cardiovascular function, and the use of antibiotics resulting in resistant strains. While an indwelling pulmonary artery catheter can provide useful monitoring information, it is sometimes responsible for serious complications in burned or septic patients.

Adult↗
PubMed1976

Phycomycotic gangrenous cellulitis. A report of two cases and a review of the literature.

Progressive gangrenous cellulitis due to Rhizopus arrhizus following colostomy destroyed the entire abdominal wall of a young woman and caused her death. A similar infection in an 11-year-old kidney transplant recipient was diagnosed more promptly and treated successfully with extensive debridement and amphotericin B. Nine similar cases found in the literature were reviewed. All 11 patients appeared to have had prior tissue injury at the original site of infection, and seven had diabetes mellitus. The disease was initially misdiagnosed in most of the patients, progressed rapidly in eight, and was fatal in four. Phycomycotic gangrenous cellulitis should be included in the differential diagnosis of progressive necrotizing lesions of the skin, especially in diabetic patients, but it can be identified promptly only by histologic examination of the infected tissue. Urgent radical excision and amphotericin therapy are recommended.

Abdominal Muscles↗