Search PubMed⌕ Search

Biomedical subjects

P Ryan

Publications and source records attributed to P Ryan.

At least 163 records · Page 9Linked to original sources
PubMed1985

Efficacy of phosphatidylcholine in the modulation of motion sickness susceptibility.

This study evaluated the efficacy of pharmacological doses of phosphatidylcholine (lecithin) in the modulation of motion sickness induced by exposure to coriolis stimulation in a rotating chair. Subjects received daily dietary supplements of 25 grams of lecithin (90% phosphatidylcholine) and were tested for their susceptibility to motion sickness after 4 h, 2 d, and 21 d. A small but statistically significant increase in susceptibility (+ 15%) was noted 4 h after supplemental phosphatidylcholine, with four of nine subjects demonstrating a marked increase in susceptibility. We attributed this finding to choline's stimulatory action on cholinergic systems, an action which opposes that of the classical antimotion sickness drug scopolamine. Chronic lecithin loading revealed a trend towards reduced susceptibility, possibly indicating the occurrence of adaptive mechanisms such as receptor down-regulation. Withdrawal from lecithin loading, perhaps coupled with anticholinergic treatment, might prove to be a potent prophylactic regimen and ought to be tested.

Coriolis Force↗
PubMed1984

Comparison of the pharmacokinetics of ceftazidime and moxalactam and their microbiological correlates in volunteers.

We compared ceftazidime with moxalactam, a commonly utilized, currently available drug. The microbiological activities of ceftazidime and moxalactam were studied. In addition, single-dose pharmacokinetics and serum bactericidal activity 1 and 6 h after a 2.0-g, 30-min infusion of each drug were determined in a crossover study in human volunteers. In vitro, both drugs had MICs for 90% of the isolates of less than 1.0 microgram/ml against the common members of the family Enterobacteriaceae and of 8.0 micrograms/ml against Staphylococcus aureus. Against Pseudomonas aeruginosa ceftazidime was more active than moxalactam, the respective MICs for 90% of the isolates being 8 and 128 micrograms/ml. Mean half-lives were 1.75 (+/- 0.21) h for ceftazidime and 2.5 (+/- 0.38) h for moxalactam. The serum bactericidal titers for both compounds against Escherichia coli and Klebsiella pneumoniae were high. Titers against S. aureus 6 h after infusion were negative. The mean (geometric) serum bactericidal titer of ceftazidime against 31 strains of P. aeruginosa (1:44) was higher than that of moxalactam (1:3.4).

Adolescent↗
PubMed1984

Contribution of education to cost-effective care of microcytic, hypochromic anemia.

Through a handbook, a seminar, and multiple opportunities for reinforcement in clinical settings, faculty in family medicine conducted an educational program that presented cost-effective practice standards for the care of anemia patients to resident physicians. A comparison of the quality and cost of anemia care by the residents before and during the program ascertained its value. The quality of patient care by residents rose significantly during the program. In addition, the residents' utilization of tests, therapy, and clinic visits and attendant costs reached more appropriate levels. These results should encourage faculty to respond to the current national need for the development of educational materials on cost-effective care of patients with common health problems.

Anemia, Hypochromic↗
PubMed1983

Changing concepts in diverticular disease.

Conventionally, acquired diverticular disease of the colon has been regarded as a single entity, so far as complications go. Experience at St. Vincent's Hospital, Melbourne, suggests that there are two kinds of diverticular disease, one with the classic muscle abnormality, chiefly confined to the left colon and characterized by inflammatory and perforative complications and the other without muscle abnormality, but with diverticula throughout the colon, in which bleeding is common, perhaps due to a connective-tissue abnormality which, on the one hand, allows development of diverticula in the absence of abnormal intraluminal pressure and, on the other, provides inadequate support for vessels in the diverticular wall or for vascular malformations, which are therefore likely to bleed. Clinical evidence from admissions to St. Vincent's Hospital suggests that both acute and chronic pain may be either inflammatory or associated with muscle spasm and hypertrophy. Finally, there is some evidence to suggest that perforation may be due often, or usually, to abnormal intraluminal pressures rather than to diverticular inflammation.

Abscess↗
PubMed1983

Guidelines for evaluating wet packs.

These guidelines are not intended to be the final word in establishment of wet pack criteria. They can serve as a starting point in development of criteria and test methodology that are scientifically defensible and practical. The joint efforts of hospital personnel and industry are necessary to continue research of the interrelated factors, such as pack preparation techniques, sterilizer operating techniques, and drying characteristics of various wraps.

Humidity↗
PubMed1982

Sigmoid volvulus with and without megacolon.

Sixty-six consecutive patients, admitted to St. Vincent's Hospital, Melbourne, with sigmoid volvulus, fell into two groups, 60 without and six with acquired megacolon. In the former group, flatus tube decompression was usually successful, and sigmoid resection provided a cure. In the group with megacolon, the history was longer; patients more often had bowel symptoms before or between acute episodes of volvulus; flatus tube decompression was rarely successful; and symptoms persisted after sigmoidectomy and were sometimes associated with recurrence of volvulus of the new "sigmoid." It seems that nothing less than total colectomy will cure these patients.

Adult↗
PubMed1982

Endorphins and mood changes in long-distance running.

Acute and chronic positive mood changes have been said to occur with running and jogging. It has been suggested that endogenous substances with opioid activity (endorphins) may serve as modulators of mood. The authors report experiments in which mood changes associated with long-distance running were measured by pre- and post-run difference--scores on a mood adjective checklist, the Profile of Mood States (POMS). Following this, the narcotic antagonist, naloxone, was given subcutaneously in double-blind fashion. The dose was 0.8 mg. The POMS was again presented 15 min later, and post-run/post-injection difference scores were obtained. No naloxone effect was found. The failure of naloxone to reverse the running-associated mood shift indicates that endorphins are not involved. The authors discuss the possible physiologic role of endorphins in light of these and other findings.

Adult↗
PubMed1982

Cell-mediated immune functions and immunoregulatory cells in Behçet's syndrome.

Lymphocyte responsiveness to mitogens (phytohaemagglutinin (PHA), concanavalin A (Con A), and pokeweed mitogen (PWM)), T-cell subsets (T mu and T gamma) and short-lived suppressor cell activity were investigated in the peripheral blood of seven patients with Behçet's syndrome and compared to normal individuals and patients with systemic lupus erythematosus (SLE). Amongst patients with Behçet's syndrome, responses to mitogens PHA and Con A were normal or slightly reduced; numbers of circulating T gamma cells were unaltered whereas T mu cells were reduced (P less than 0 . 05) compared with normal individuals. This was in contrast to SLE where a marked reduction in responses to PHA and Con A was found with reduced T gamma cell but normal T mu cell numbers. Although the mean suppressor cell activity in the Behçet's group was significantly reduced, all patients had values within the normal range, in contrast with SLE where the reduction was much more marked and most patients had values below the normal range. In conclusion, the pattern of alteration in T mu and T gamma cells in Behçet's syndrome is distinct from that in SLE, and the reduction of short-lived suppressor cell activity is only mild in Behçet's syndrome but marked in SLE.

Adult↗
PubMed1980

Hydralazine-induced systemic lupus erythematosus: influence of HLA-DR and sex on susceptibility.

26 patients with systemic lupus erythematosus (SLE) induced by treatment with the antihypertensive drug hydralazine were investigated to determine if predisposition to the toxic effect was associated with an HLA-DR antigen. 25 of the 26 patients were slow acetylators. The group was compared with three others (1) 113 healthy subjects, untested for acetylator phenotype, (2) 16 slow-acetylator hypertensive patients treated with hydralazine for more than a year without developing SLE, and (3) 20 patients with idiopathic SLE. The frequency of HLA-DR4 (73%) was significantly higher in the group with hydralazine-induced SLE than in the other groups (respectively 33%, 25%, and 25%). The ratio of women to men affected was 4:1. If the slow acetylators treated with hydralazine were analysed as one group, it was observed that all women with DR4 developed hydralazine-induced SLE; the only men to do so were those with DR2 who were receiving 200 mg hydralazine per day. These observations have led us to suggest guide lines for hydralazine therapy and point to a striking association between an HLA-DR antigen and an adverse reaction to a therapeutic agent. It was also noted that the distribution of DR antigens in the hydralazine-SLE patients was significantly different from that in the group with idiopathic SLE. This supports the view that the syndromes are separate entities.

Acetylation↗
PubMed1980

Routine or indicated operative cholangiography?

An assessment was made both the reliability of routine operative cholangiography and of the incidence of unsuspected common duct stones identified by this technique. It is suggested that its disadvantages, in particular the incidence of unnecessary bile duct explorations consequent upon false-positive cholangiograms, make routine operative cholangiography undesirable. If any suspicion of common duct stone exists by virtue of clinical, biochemical or operative findings, an operative cholangiogram should be performed. Following adoption of this policy our findings suggest that the incidence of undetected stone will be negligible.

Cholangiography↗
PubMed1980

Observations upon the aetiology and treatment of complete rectal prolapse.

The classical abnormalities found in patients with complete rectal prolapse--wide deep pelvic peritoneal pouch, unsupported redundant rectum with long mesorectum, weak pelvic floor and anal sphincters--are probably effects rather than causes. "Pelvic floor weakness" must explain few cases, since old age, multiparity, uterine prolapse, are found in a minority. The fact that operations which do no more than fix the rectum in the sacral hollow are most successful and often cure incontinence if present is the best evidence that lack of support of the rectum is a prime cause of prolapse--but it is equally likely that such operations work by preventing intussusception, now regarded as the likely mechanism (rather than sliding herniation) of complete rectal prolapse. It is suggested that rectal prolapse is usually due to straining at defaecation against a closed levator-ani--anal-sphincter mechanism, producing prolapse of the rectum rather than incontinence of faeces. Such straining may be obsessive on the part of patients with psychosocial problems and reduced awareness that the rectum is empty; or it may be due to attempted defaecation with a full rectum in patients with reduced rectal sensation, failure of the afferent arc of the ano-rectal reflex and consequent absence of levator-ani--anal-sphincter relaxation.

Adult↗