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Biomedical subjects

J M Hayes

Publications and source records attributed to J M Hayes.

At least 145 records · Page 8Linked to original sources
PubMed1985

Clinical application of in vitro studies for barium-enema examination following colorectal biopsy.

A total of 150 colorectal biopsies were performed in 71 patients and correlated with the barium-enema examination (BE). The investigation was divided into two parts. In the first part, involving 19 patients, the depth of each biopsy specimen was determined histologically prior to BE and potential complications related to the biopsy-BE sequence were evaluated. In the second part, involving all 71 patients, the depth of biopsy specimens taken from various colon lesions was determined histologically without regard to the timing of BE. The results confirm previous in vitro findings in pigs and dogs, namely: (a) BE may be performed without delay following a superficial biopsy, but should not be performed until at least 6 days after a deep biopsy; (b) transcolonoscopic biopsies are likely to be superficial, while transproctoscopic biopsies have the potential to be deep; and (c) BE should be delayed at least 6 days following polypectomy or polyp biopsy performed with electrosurgery.

Barium Sulfate↗
PubMed1985

Terfenadine, a nonsedating antihistamine.

Terfenadine is an antihistamine recently approved for use in the U.S. Terfenadine possesses a unique chemical structure when compared with other antihistamines. It is a selective inhibitor of H1-receptors with little or no anticholinergic, antiserotoninergic, or antiadrenergic effects. Comparative studies have shown that terfenadine is as effective as other antihistamines in the treatment of allergic rhinitis and other hypersensitivity conditions. This drug produces a minimal amount of central nervous system (CNS) depression, which is documented by studies demonstrating that terfenadine and its metabolites do not readily pass into the CNS and have little affinity for central H1-receptors. The lack of CNS depression and anticholinergic effects, and the long duration of action that allows twice-a-day dosing make terfenadine an attractive alternative to other antihistamines.

Benzhydryl Compounds↗
PubMed1985

Millimeter-scale variations of stable isotope abundances in carbonates from banded iron-formations in the Hamersley Group of Western Australia.

Several diamond drill cores from formations within the Hamersley Group of Western Australia have been studied for evidence of short-range variations in the isotopic compositions of the carbonates. For a set of 32 adjacent microbands analyzed in a specimen from the Marra Mamba Iron Formation, carbon isotope compositions of individual microbands ranged from -2.8 to -19.8 per mil compared to PDB and oxygen isotope compositions ranged from 10.2 to 20.8 per mil compared to SMOW. A pattern of alternating abundances was present, with the average isotopic contrasts between adjacent microbands being 3.0 per mil for carbon and 3.1 per mil for oxygen. Similar results were obtained for a suite of 34 microbands (in four groups) from the Bruno's Band unit of the Mount Sylvia Formation. Difficulties were experienced in preparing samples of single microbands from the Dales Gorge Member of the Brockman Iron Formation, but overall isotopic compositions were in good agreement with values reported by previous authors. Chemical analyses showed that isotopically light carbon and oxygen were correlated with increased concentrations of iron. The preservation of these millimeter-scale variations in isotopic abundances is interpreted as inconsistent with a metamorphic origin for the isotopically light carbon in the BIF carbonates. A biological origin is favored for the correlated variations in 13C and Fe, and it is suggested that the 13C-depleted carbonates may derive either from fermentative metabolism or from anaerobic respiration. A model is presented in which these processes occur near the sediment-water interface and are coupled with an initial oxidative precipitation of the iron.

Australia↗
PubMed1983

Axillary artery injury with minimally displaced fracture of the neck of the humerus.

A case of axillary artery injury resulting from a minimally displaced fracture of the neck of the humerus is reported. Very few such injuries have been reported previously. The mechanism of injury can be from sharp bony fragments, overstretching of the artery especially when atheromatous, or torn intima. Angiography should be performed, followed by exploration where indicated.

Accidents, Home↗
PubMed1983

Acute renal failure in the intensive care unit--clinical considerations.

The pathogenesis of acute renal failure remains uncertain. From a clinical viewpoint the magnitude of the problem of nephrotoxic acute renal failure is now recognised as is the frequency of non-oliguric acute renal failure. Advances in patient management include the use of daily dialysis, lower heparin doses, single-needle dialysis, bicarbonate-base dialysis fluid, artificial kidneys with biocompatible membranes, H2 antagonists, and the use of soft silastic Tenckhoff catheters if peritoneal dialysis is the preferred form of therapy.

Abdomen↗
PubMed1982

Biosynthetic control of the natural abundance of carbon 13 at specific positions within fatty acids in Saccharomyces cerevisiae. Isotopic fractionation in lipid synthesis as evidence for peroxisomal regulation.

Measurements of the natural abundance of 13C at C-1, C-9, and C-10 in fatty acids synthesized by Saccharomyces cerevisiae grown aerobically at 30 degrees C show that alkyl chain positions derived from the carboxyl group of the acetate precursor must be enriched in 13C by 2.5 +/- 0.6 parts per thousand while those derived from the methyl group in acetate must be depleted in 13C by an equal amount. Selective depletions of 13C observed at the C-9 and C-10 positions of palmitoleate and oleate require that (i) the carbon kinetic isotope effect associated with the action of desaturase at C-9 must be between 1.2 and 1.6% in vivo, (ii) at C-10 the effect must be between 0.9 and 1.3%, and (iii) less than 20% of the C18 carbon skeletons synthesized are preserved within the cell, the remainder apparently being degraded. It is shown that the novo synthesis (i.e. by fatty acid synthetase) is responsible for the production of more than 95% of the supply of 18-carbon acyl groups, the remainder being provided by all other elongation pathways. In an ancillary study designed to test the accuracy and generality of these results, it was observed that still larger specific depletions occurred at olefinic carbon position in fatty acids from soybeans, thus suggesting that the degradation of substantial quantities of C18 carbon skeletons may be a widespread feature of fatty acid metabolism in eukaryotes. It is suggested that the required degradation is associated with the action of peroxisomes.

Carbon Isotopes↗
PubMed1981

Penicillamine-induced "Goodpasture's syndrome": successful treatment of a fulminant case.

Goodpasture's syndrome is a recognised but rare complication of penicillamine therapy. Return of useful renal function has no been recorded with this complication. A patient is presented in whom aggressive management with plasmapheresis, haemodialysis and immunosuppression in the acute stage resulted in rapid control of pulmonary haemorrhage and return of useful renal function without the need for long-term haemodialysis. Immunofluorescence and electron microscopic studies of renal tissue together with the demonstration of circulating immune complexes, established the immune complex pathogenesis of this patient's disease. Microhaematuria is emphasised as an important warning sign of this complication.

Anti-Glomerular Basement Membrane Disease↗
PubMed1981

Fulminant lupus pneumonitis with acute renal failure and RBC aplasia. Successful management with plasmapheresis and immunosuppression.

Acute interstitial pneumonitis is a well-recognized, although rare, complication of systemic lupus erythematosus (SLE) that has been associated with a poor prognosis. Fulminant lupus pneumonitis, acute renal failure, and RBC hypoplasia occurred in a 14-year-old girl. The patient's condition was managed with large-volume plasmapharesis, dialysis, and immunosuppressive therapy. Her respiratory, renal, and hematologic changes all resolved, and response was maintained with cyclophosphamide and prednisolone therapy. Although serologic evidence of SLE persisted, clinically, the patient was well four years after the initial appearance of SLE. There are several acute pulmonary manifestations of SLE, and plasmapheresis may be useful in the management of some of these conditions.

Acute Kidney Injury↗
PubMed1980

Biosynthetic control of the natural abundance of carbon 13 at specific positions within fatty acids in Escherichia coli. Evidence regarding the coupling of fatty acid and phospholipid synthesis.

Stable carbon isotope ratios (13C/12C) at natural abundance levels have been determined for individual carbon atoms in each of the major phospholipid fatty acids of Escherichia coli grown on glucose as the sole carbon source. Two models were constructed for the isotope effects and carbon flow pathways which must be responsible for the observed isotopic fractionations. Both models incorporate a branch in the carbon flow at which fatty acyl-acyl carrier protein (acyl-ACP) is utilized either for complex lipid synthesis or for elongation by fatty acid synthetase. Depletion of carbon 13 in the carboxyl groups of myristic and palmitoleic acids (relative to carbonyl groups in precursor acyl-ACP's) was observed to occur at this branching site. Only one of the models was consistent both with this observation and with the observation (Silbert, D. F., Ruch, F., and Vagelos, P. R. (1968) J. Bacteriol. 95, 1658-1665) that exogenous fatty acids are incorporated into phospholipids but are not elongated. The successful model has free fatty acid as the intermediate product coupling fatty acid biosynthesis to phospholipid synthesis. Essential to this pathway are those reactions catalyzed by thioesterases I and II as well as acyl-ACP synthetase, enzymes whose roles have previously been unknown in vivo.

Acyl Carrier Protein↗
PubMed1978

Circulating thyroid hormone levels and adequacy of dialysis.

In vitro thyroid function tests were performed in three groups of patients with chronic renal failure who were receiving, on average, 15, 18 and 27 hours of maintenance hemodialysis per week. Total thyroxine levels were low and total triiodothyronine levels low to normal in those receiving the least dialysis (15 hours), and were significantly higher in those receiving longer dialysis. Free thyroxine levels, as measured by the effective thyroxine ratio, were normal and similar in all three groups, as were serum thyrotrophin levels. All patients were clinically euthyroid. As total hormone levels showed a significant inverse relationship to both urea and creatinine, this study suggests that there is a dialyzable metabolite retained in uremia which competes with thyroid hormones for protein-binding sites.

Adult↗
PubMed1976

Hypophosphataemic osteomalacia in patients receiving haemodialysis.

Four patients had symptomless osteomalacia at the time of starting regular haemodialysis. After 21-40 months they became hypophosphataemic and developed disabling skeletal symptoms. In each case an exacerbation of histological osteomalacia was shown. Symptoms improved after measures designed to raise serum inorganic phosphate concentrations or vitamin D administration, or both. Patients undergoing maintenance haemodialysis should have their serum phosphate and alkaline phosphatase levels monitored every month. Predialysis phosphate levels below 1 mmol/1 (3 mg/100 ml) and rising serum alkaline phosphatase concentrations are danger signals. If the diagnosis is confirmed early aggressive treatment should be started.

Adolescent↗
PubMed1976

Experience with prazosin in the treatment of patients with severe hypertension.

The efficacy and safety of prazosin, a new vasodilator antihypertensive agent, used mainly in combination with other hypotensive medication, was evaluated in 50 hypertensive patients, 28 of whom had left ventricular hypertrophy and 28 of whom had renal impairment. In 44 cases this agent was introduced because of an inadequate response to, or side effects from other agents. In 38 cases (76%) there was a satisfactory response, the diastolic blood pressure being reduced to 100 mm Hg or less. The blood pressure of the whole group of 50 patients was reduced by an average of 31/20 mm Hg. The mean duration of therapy was 6-6 months. Side effects necessitating withdrawal of prazosin occurred in only three cases. Plasma renin activity was reduced to 25% of the control value in a group treated with prazosin alone.

Adult↗