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Biomedical subjects

M Ryan

Publications and source records attributed to M Ryan.

At least 19 recordsLinked to original sources
PubMed1992

Intracarotid norepinephrine infusions inhibit ventilation in goats.

Plasma norepinephrine (NE) increases from rest to exercise during normoxic exercise, and significantly more during hypoxic exercise in goats. To determine carotid body (CB) mediated effects of increased NE on ventilatory control, we investigated ventilatory responses to intracarotid NE infusions in awake, resting goats. NE was infused (0.5-5.0 micrograms.kg-1 x min-1, 2-3 min) into either a CB intact or contralateral CB-denervated carotid artery in both normoxia and hypoxia (FIO2. = 0.11). PRE-infusion measurements of arterial blood gases, blood pressure and pulmonary ventilation (VI) were compared with values 30-45 sec after beginning NE infusions at 1.0 micrograms.kg-1 x min-1. On the CB-intact side, NE infusions decreased VI by an average of 43% (P < 0.05) and increased PaCO2 4.0 +/- 0.3 mmHg (P < 0.05); ventilatory inhibition preceded an increase in arterial blood pressure. NE infusions on the CB-denervated side had no significant effects on VI or PaCO2, but still increased blood pressure to the same level as infusions on the CB-intact side. In hypoxia, NE infusions on the intact side no longer inhibited VI. NE induced VI inhibition in normoxia was similar in magnitude and time course to dopamine induced VI inhibition. Experiments were repeated following administration the alpha-adrenergic receptor antagonist, phenoxybenzamine (1 mg.kg-1, i.v.) the beta-adrenergic receptor antagonist, propranolol (1 mg.kg-1, i.v.) and the D2-dopamine receptor antagonist, domperidone (1 mg.kg-1, i.v.). Phenoxybenzamine partially blocked NE induced ventilatory depression and domperidone blocked it, but propranolol had no effect. These data indicate that NE inhibits ventilation in goats via effects on carotid chemoreceptors. NE induced inhibition is independent of changes in blood pressure or baroreceptor feedback, and appears to involve both alpha-adrenergic and D2-dopaminergic receptors.

Animals↗
PubMed1992

Lithostar extracorporeal shock wave lithotripsy: the first 1,000 patients. Toronto Lithotripsy Associates.

To our knowledge this study of our first consecutive 1,000 patients treated with the Siemens Lithostar device is the largest prospective series reported to date. Treatment results were determined at 3, 12 and 24 months after completion of therapy. The results at 3 months are presented. Complete followup data were available on 801 patients: 674 with renal and 127 with ureteral calculi. Results were analyzed according to stone size, location and number. The average number of shocks per treatment was 3,804 and the retreatment rate was 18.6%. At 3 months the stone-free rate was determined by a plain film of the kidneys, ureters and bladder and plain tomograms for renal calculi, and by an excretory urogram for ureteral calculi. The stone-free rate was 52% for renal and 76% for ureteral calculi. The overall stone-free rate for all calculi was 55.7%. Success rate, defined as stone-free or asymptomatic residual fragments measuring 4 mm. or less, was 72% for renal and 83% for ureteral calculi. The overall success rate for all calculi was 73.9%.

Female↗
PubMed1992

Biocultural synthesis in medical anthropology.

Medical anthropology has developed distinct and separate biological and cultural approaches to the study of health and disease in human populations. Within cultural anthropology a major focus has been the ethnomedical perspective that analyzes the process of defining disease and describing the social response to disease. In biological anthropology, an ecological perspective considers the interaction of the population, the insult and the environment at the core of the disease process. There has been limited success in integrating the cultural and biological perspective. Some cultural anthropologists claim that the ecological perspective relies on a biomedical model and therefore is not useful in studying non-Western societies. Others are critical of the adaptivist perspective that they believe fails to consider political economic factors that affect the disease process. The lack of a biocultural integration has hindered the systematic analysis of health and disease in contemporary traditional and non-Western groups. An ecological model that addresses these problems will provide a biocultural integration of the disease process.

Adaptation, Psychological↗
PubMed1992

Computerised protocols for laboratory investigation and their effect on use of medical time and resources.

AIMS: To devise a computerised management system protocol which not only proposes the laboratory investigations to be performed on each patient but also performs related clinical functions. METHODS: The system was designed by senior members of staff. The protocols defined all laboratory investigations including haematology, biochemistry, immunology and cross-matching, and included static and dynamic rules. Patients can be changed to different or additional protocols, as required; likewise proposed tests can be deleted or added. The software is written in MUMPS and runs on a 386 PC running MSM MUMPS under MSDOS. RESULTS: The number of clinical chemistry tests requested per patient per day fell by 9.5% (p less than 0.01) for transplant recipients and by 28.8% (p less than 0.01) for non-transplant recipients. The average time spent by junior medical staff requesting laboratory investigations and enquiring about results fell from 10 minutes per patient per day to 4.1 minutes (p less than 0.001). CONCLUSIONS: The introduction of this system in no way abrogates clinicians' responsibility for the management of patients, because all proposed investigations must be confirmed or modified by the authorising doctor. The system allows for the audit of requesting patterns and subsequent improvement in protocols by recording any alterations made to the proposed investigations. Significant benefits in terms of better use of house officer time and medical resources were also achieved.

Clinical Laboratory Information Systems↗
PubMed1992

A changing pattern of epiglottitis.

A case review of epiglottitis at Geisinger Medical Center over the past 12 years demonstrates a decrease in the number of pediatric patients with epiglottitis and an increase in the number of adults with epiglottitis. In the last five years, the number of epiglottitis patients younger than 10 years has fallen (0 cases), while the number of patients over 10 years of age has increased (6 cases). The cause of epiglottitis, Hemophilus influenzae type b, remains constant in the pediatric as well as in the adult population. There appears to be an increasing frequency of epiglottitis in adults and a decreasing frequency of epiglottitis in children.

Adult↗
PubMed1992

Pain, opioid use, and survival in hospitalized patients with advanced cancer.

PURPOSE: Pain is a common and feared symptom for patients with incurable cancer. Comprehensive assessment provides the foundation for effective pain management, and data that clarify the relationship between pain and other relevant factors also facilitate this process. The main objective of the study was to develop a clinical data base for advanced cancer patients and to survey data to determine (1) pain severity at admission, (2) opioid use at admission, (3) change in opioid use during the hospital stay, and (4) survival in the hospital. PATIENTS AND METHODS: Information was collected prospectively on 1,103 patients admitted and on 1,017 patients who died within 6 months of the study's end. Demographic and clinical data were recorded 72 hours after admission and soon after death or discharge. RESULTS: Seventy-three percent of patients had pain at admission. Cancer of the cervix was frequently (68%) associated with severe pain, as were prostate (52%) and rectal/sigmoid tumors (49%). Severe pain was more probable in those with bone metastasis, those admitted from home, and in those younger than 55 years of age. The majority (71.7%) of patients had a stable dosing pattern, and only 4.2% of the patients required dose increases of at least 10% per day. CONCLUSION: This study demonstrated the wide variability in opioid doses required. No reliable predictor of opioid requirement was identified, and this lack of predictability of cancer pain severity underscores the need for ongoing assessment.

Adult↗
PubMed1992

Knowledge of drug costs: a comparison of general practitioners in Scotland and England.

The implementation of drug budgets will make it essential that general practitioners are aware of prescribing costs. A previous study of general practitioners in Scotland found that their knowledge of drug costs was often inaccurate. At the time of the Scottish study, doctors received very limited information on prescribing costs. By contrast, general practitioners in England have been receiving much more detailed information on their prescribing costs since the introduction of PACT (prescribing analyses and cost) in 1988/89. This study examines whether, as a result, doctors in England are more aware of drug costs. The results suggest that they are not; indeed, doctors in Scotland had marginally better knowledge of drug costs. There is a continuing need to improve the cost information available to general practitioners.

Awareness↗
PubMed1991

Charging for health care: evidence on the utilisation of NHS prescribed drugs.

The effects of regular and frequent increases in charges for health care on patient utilisation are analysed using monthly data on National Health Service (NHS) prescribed drugs in England for the period 1979-1985. Using a partial adjustment model a utilisation equation of prescribed drugs is estimated for the adult non-elderly population that is subject to the NHS prescription charge. The maximum likelihood estimates of the coefficients of the equation imply that the charges policy followed in the U.K. has led to a significant reduction in utilisation among non-exempt patients. The short-run price elasticity of utilisation is -0.109 and the long-run elasticity is -0.09, while exempt utilisation is unaffected. Although the policy has generated a reduction in the central Government expenditure for prescribed drugs, on the basis of these estimates around 66% of these savings arise from the reduction in service use as opposed to the increased revenue per item of drugs.

Drug Prescriptions↗
PubMed1991

Comparative toxicity and tissue distribution of antimony potassium tartrate in rats and mice dosed by drinking water or intraperitoneal injection.

Antimony potassium tartrate (APT) is a complex salt that until recently was used worldwide as an antischistosomal drug. Treatment was efficacious only if APT was administered intravenously to humans at a near lethal total dose of 36 mg/kg. Because unconfirmed epidemiologic studies suggested there might be an association between APT treatment and bladder cancer, we initiated prechronic toxicity studies with the drug to select a route of administration and doses in the event that chronic studies of APT were needed. The toxicity and concentration of tissue antimony levels were compared in 14-d studies with F344 rats and B6C3F1 mice administered APT in the drinking water or by ip injection to determine the most appropriate route for longer term studies. Drinking water doses estimated by water consumption were 0, 16, 28, 59, 94 and 168 mg/kg in rats and 0, 59, 98, 174, 273, and 407 mg/kg in mice. APT was poorly absorbed and relatively nontoxic orally, whereas ip administration of the drug caused mortality, body weight decrements, and lesions in the liver and kidney at doses about one order of magnitude below those in drinking water. Because of these data and the dose-related accumulation of antimony in the target organs, an ip dose regimen was selected for subsequent studies. Both sexes of F344 rats and B6C3F1 mice were given 0, 1.5, 3, 6, 12, and 24 mg/kg doses of APT every other day for 90 d by ip injection. There were no clinical signs of toxicity nor gross or microscopic lesions in mice that could be attributed to toxicity of APT, although elevated concentrations of antimony were detected in the liver and spleen of mice. Rats were more sensitive than mice to the toxic effects of APT, exhibiting dose-related mortality, body weight decrements, and hepatotoxicity. The concentrations of antimony measured in liver, blood, kidney, spleen, and heart of rats were proportional to dose, but there were no biochemical changes indicative of toxicity except in the liver. Hepatocellular degeneration and necrosis occurred in association with dose-related elevations in activities of the liver-specific serum enzymes sorbitol dehydrogenase and alanine aminotransferase. By alternating the site of abdominal injection and the days of treatment, mesenteric inflammation at the site of administration was minimized in the rats and mice, indicating that the ip route would be suitable for chronic studies.(ABSTRACT TRUNCATED AT 400 WORDS)

Administration, Oral↗
PubMed1991

Magnetic resonance imaging in the assessment of rheumatoid arthritis--a comparison with plain film radiographs.

Conventional radiography lacks sensitivity in early rheumatoid disease. MRI with its advantages of soft tissue discrimination and multiplanar imaging facility might detect earlier disease. This study compares the MR images and conventional radiographs of 11 rheumatoid patients' wrists and carpi. In all cases, erosions were more extensive and numerous on the MR images compared to plain radiographs. MR is useful in detecting early aggressive disease and in monitoring the response to treatments.

Adult↗