Search PubMed⌕ Search

Biomedical subjects

D Lloyd

Publications and source records attributed to D Lloyd.

At least 217 records · Page 12Linked to original sources
PubMed1986

Antibiotic prophylaxis and secondary haemorrhage following transurethral resection of the prostate: a prospective trial.

One hundred and sixty-two patients were studied in a random double-blind controlled trial of co-trimoxazole to prevent secondary haemorrhage following transurethral resection of the prostate (TURP). There was a significant correlation between the incidence of post-operative urinary infection and secondary haemorrhage (P less than 0.05) but no difference between the incidence of bleeding in the treatment and placebo groups. Although infection may play a role in the development of secondary haemorrhage, co-trimoxazole for 10 days does not decrease the incidence of this complication.

Aged↗
PubMed1986

Detection of pathological tachycardia by analysis of electrogram morphology.

Pacemaker recognition of pathological tachycardia relies on heart rate analysis. This can lead to misdiagnosis when sinus tachycardia exceeds the preset tachycardia response trigger rate. We have explored a method for automatic tachycardia diagnosis by analysis of bipolar endocardial electrogram morphology. Electrograms were recorded from 11 patients (pts) during sinus rhythm and during a total of 20 abnormal rhythms: retrograde atrial depolarization from ventricular pacing in six patients; atrioventricular reentry tachycardia in five patients with intermittent left bundle branch block in one of those; AV nodal reentry tachycardia in five patients and ventricular tachycardia in three patients. Posture and respiration were varied during all rhythms except ventricular tachycardia. The electrograms were then digitized and converted to a form in which the amplitudes were proportional to the rates of change of the original electrogram (equivalent to a first time derivative); the derived signal was then analyzed by a new gradient pattern detection (GPD) program. Analysis of the processed atrial signals by GPD resulted in automatic recognition of abnormal rhythms from sinus rhythm in all cases except for one patient's retrograde atrial depolarization. At the ventricular level, GPD successfully distinguished all abnormal rhythms from sinus rhythm including recognition of left bundle branch block and varying degrees of preexcitation. Respiratory and postural variation did not affect the recognition process. We conclude that electrogram GPD has successfully and automatically detected a variety of arrhythmias which can be treated by implantable pulse generators and may, therefore, be a useful adjunct to heart rate analysis in future generations of such antitachycardia pacemakers.

Adolescent↗
PubMed1986

Host defence in continuous ambulatory peritoneal dialysis: the effect of the dialysate on phagocyte function.

Peritoneal dialysis fluid was examined after dwell periods of from 30 min to 18 h. Macrophages formed more than 70% of all cells recovered, irrespective of dwell time. The viability of these cells was 95% or greater even in 30 min effluent. Peritoneal macrophages and polymorphonuclear leucocytes were incubated in unused peritoneal dialysis fluid. By 30 min the viability of polymorphonuclear leucocytes had fallen to 50% but that of peritoneal macrophages was still 84%. However, phagocytosis of unopsonized zymosan by both cell types was depressed after only 10 min exposure. Peritoneal dialysis effluents obtained after dwell times of 30-180 min were examined for their effect on phagocytosis in vitro. These fluids suppressed peritoneal macrophages function as compared to RPMI 1640. Effluent after an overnight dwell did not affect phagocytosis. The suppressant effect decreased with increasing dwell time. Polymorphonuclear leucocytes were affected to a greater degree than peritoneal macrophages. Tests showed that this decreased phagocytosis was not due to cell death nor was it due to the osmolality or lactate content of the dialysate. Adjusting pH only improved cell function slightly. Phagocyte function appears to be depressed for clinically significant periods of the CAPD cycle.

Humans↗
PubMed1985

Degradative inactivation of the peroxisomal enzyme, alcohol oxidase, during adaptation of methanol-grown Candida boidinii to ethanol.

Adaptation of methanol-grown C. boidinii to ethanol-utilization in non-growing cells resulted in decreased activity of the peroxisomal enzyme alcohol oxidase. Re-appearance of alcohol oxidase activity was dependent on protein synthesis de novo. Degradation of alcohol oxidase protein was shown to parallel the decrease in activity. Adaptation of methanol-grown cells to ethanol-utilization resulted in increased absorbance due to cytochromes and decreased absorbance due to flavoprotein. Decrease in alcohol oxidase activity was associated with loss of the flavin coenzyme, FAD, from the organisms and the appearance of flavins (FAD, FMN, riboflavin) in the surrounding medium. Electron microscopic observations showed that general degradation of whole peroxisomes rather than specific loss of crystalline cores (alcohol oxidase protein) occurred during the adaptation.

Adaptation, Physiological↗
PubMed1985

13C-NMR reveals glycerol as an unexpected major metabolite of the protozoan parasite Trichomonas vaginalis.

13C-NMR has been used to study the kinetics of the formation of metabolites from [1-13C]glucose in intact cells of Trichomonas vaginalis during anaerobic incubation. As well as the expected metabolites lactate and acetate, this technique revealed glycerol as an additional major product, present in amounts equimolar with acetate. The formation of glycerol is readily explained in terms of the need to maintain redox balance. This protozoan now joins the small group of organisms which are known to produce glycerol as a result of normal metabolic activities.

Acetates↗
PubMed1985

Butyrate formation from glucose by the rumen protozoon Dasytricha ruminantium.

Production of butyrate by the holotrich protozoon Dasytricha ruminantium involves the enzymes of glycolysis, pyruvate:ferredoxin oxidoreductase, acetyl-CoA:acetyl-CoA C-acetyltransferase, 3-hydroxybutyryl-CoA dehydrogenase, 3-hydroxyacyl-CoA hydro-lyase, 3-hydroxyacyl-CoA reductase, phosphate butyryltransferase and butyrate kinase. Subcellular fractionation by differential and density-gradient centrifugation on sucrose gradients indicated that all those enzymes except pyruvate:ferredoxin oxidoreductase were non-sedimentable at 6 X 10(6) g-min. Butyrate kinase and phosphate butyryltransferase were associated with the large- and small-granule fractions. Thus, although metabolic reactions necessary for butyrate production proceed predominantly in the cytosol, hydrogenosomes play a key role in the conversion of pyruvate into acetyl-CoA.

Animals↗
PubMed1985

Management of adenocarcinoma in a columnar-lined esophagus.

Of 89 patients diagnosed between 1973 and 1983 as having at least 3 cm of columnar-lined esophagus, 22 were found to have adenocarcinoma. There was no difference in sex ratio, smoking, or the use of alcohol between the benign and adenocarcinoma groups. The patients with adenocarcinoma were older (63 years versus 57 years) and had a higher frequency of dysphagia (64% versus 46%), gastrointestinal bleeding (36% versus 24%), extended columnar-lined esophagus (94% versus 28%), and epithelial dysplasia (68% versus 10%). Heartburn was less frequent in the adenocarcinoma group (59% versus 79%), but when it occurred, it was of longer duration (mean, 18.8 years versus 10.9 years). In 2 patients, progression from benign columnar-lined esophagus to early adenocarcinoma was observed. Of the patients with adenocarcinoma, 2 received palliative treatment without resection and died four and nine months later. Six underwent partial esophagogastrectomy with 1 postoperative death. Four had residual columnar-lined esophagus at the resection margins. In one of them, stricture developed and in one, anastomotic recurrence of adenocarcinoma; 1-year survival was 50%. Fourteen patients underwent total thoracic esophagectomy with no operative deaths, strictures, or anastomotic recurrences; 1-year survival was 5 of 6. Surgical staging revealed that 63% had transmural spread and 55%, lymph node involvement.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenocarcinoma↗
PubMed1985

Metronidazole radical anion generation in vivo in Trichomonas vaginalis: oxygen quenching is enhanced in a drug-resistant strain.

The nitro radical-anion of metronidazole has been detected in vivo in the sexually transmitted human parasite, Trichomonas vaginalis, under anaerobic conditions by electron spin resonance spectrometry. Exposure of organisms to oxygen decreased the intensity of the radical signal in both metronidazole-sensitive ATCC strain 30001 and in the metronidazole-resistant strain 85. The sensitive strain still gave radical signals at partial pressures of oxygen (greater than 6 kPa) sufficient to remove all detectable radicals from the resistant strain. This evidence suggests that the resistant strain has defective oxygen scavenging system(s).

Aerobiosis↗
PubMed1985

Energy-dispersive X-ray microanalysis of membrane-associated inclusions in hydrogenosomes isolated from Trichomonas vaginalis.

Energy-dispersive X-ray microprobe analysis of electron-dense inclusions in hydrogenosomes isolated from the aerotolerant anaerobic protozoal human parasite Trichomonas vaginalis, Bushby strain, indicated the presence of high levels of Mg, P and Ca. This suggested that divalent cation (e.g. Ca2+ or Mg2+) accumulation by hydrogenosomes may be important in the regulation of intracellular ion concentrations.

Calcium↗
PubMed1985

Metronidazole inhibition of hydrogen production in vivo in drug-sensitive and resistant strains of Trichomonas vaginalis.

H2 production by the human protozoan parasite Trichomonas vaginalis was monitored continuously under a mobile gas phase using a membrane-inlet mass spectrometer. Simultaneous and continuous measurement of dissolved H2, O2 and CO2 indicated that H2 evolution was inhibited at levels of O2 (less than 0.25 microM) undetectable by the technique, whereas CO2 production was stimulated. Respiration was not stimulated by admitting H2 to the gas phase. Metronidazole inhibited both H2 and CO2 production. Values of K1 for inhibition of H2 formation in strain ATCC 30001 (metronidazole sensitive) of 0.16 mM and in strain 85 (metronidazole resistant) of 1.0 mM were obtained. These data suggest that metronidazole not only competes with protons as electron acceptor but that the drug itself or a product of reduction actively inhibits some hydrogenosomal enzyme or electron carrier involved in H2 production. Under these conditions metronidazole inhibition leads to irreversible loss of cell motility.

Carbon Dioxide↗
PubMed1985

The generation of metronidazole radicals in hydrogenosomes isolated from Trichomonas vaginalis.

The nitro radical-anion of the anti-trichomonal drug metronidazole has been detected by electron spin resonance spectrometry under anaerobic conditions in suspensions of intact hydrogenosomes isolated from the parasitic protozoon Trichomonas vaginalis. Metronidazole reduction was driven by pyruvate, but progressive damage to the radical generating system was observed. Quenching of signals due to metronidazole radicals by chromium oxalate suggests that the radicals generated within the organelle can cross the hydrogenosomal membrane into the external medium. Even if a similar process of radical migration occurs in vivo, it seems likely that intrahydrogenosomal damage may explain drug action.

Electron Spin Resonance Spectroscopy↗
PubMed1984

Memory disturbance in chronic progressive multiple sclerosis.

Forty-four patients with chronic progressive multiple sclerosis (MS) were compared with age- and education-matched control groups on a battery of clinical and experimental memory measures. Patients with MS performed substantially below the control groups on both immediate learning and delayed recall tasks, particularly in the retrieval of spatial information. The MS sample was subdivided into three groups using a cluster analytic procedure. One group (N = 9) performed well below expectations on memory tasks, exhibited signs of global cognitive disturbance, and had an atypical personality adjustment, characterized by irritability, social withdrawal, and apathy. A second group (N = 19) showed mild memory disturbance, associated with a greater use of psychotropic medications and a higher incidence of reactive depression. A third group (N = 16) performed normally on memory measures. The three groups of patients with MS did not differ in length or overall severity of illness.

Adult↗
PubMed1984

Spontaneous chylothorax in newborns.

During a 22-year period, 12 cases of spontaneous chylothorax in newborns were diagnosed at a large pediatric tertiary care center. Seven infants had right-sided effusions; only one effusion occurred on the left. Severe bilateral accumulations occurred in four nonimmune hydropic premature infants. The diagnosis was made by the milky appearance and/or the presence of more than 80% lymphocytes in the pleural fluid. Early diagnosis of the pleural effusion as chyle was associated with a less protracted course than when diagnosis was delayed. The total pleural fluid losses varied from 130 to 3,308 mL. Initial treatment included chest taps and/or drains in all the infants and mechanical ventilation in six. Oral feedings with standard or medium-chain triglyceride formulas were given in five; total parenteral nutrition was administered in seven. The conditions of two infants with copious and persistent drainage improved following surgery. All but one infant survived, and the chylothoraxes never recurred.

Chylothorax↗
PubMed1984

Simple colorimetry of glycated serum protein in a centrifugal analyzer.

A recently described (Clin Chim Acta 127: 87-95, 1982) colorimetric assay for glycated proteins in serum exploits their ketoamine activity to reduce 3,3'-(3,3'-dimethoxy-4,4'-biphenylylene)bis [2-(p-nitrophenyl)-5-phenyl-2H-tetrazolium chloride] (nitroblue tetrazolium) in alkaline solution; the authors termed this the "fructosamine assay." The method is simple, requiring only the addition of one reagent and measurement of the absorbance change during 5 min; results are expressed relative to a synthetic standard. We have adapted this for use in a centrifugal analyzer and report its performance, both analytically and as an index of hyperglycemia. Precision is good (between-batch CV 2.1%), the reagent is stable and inexpensive, and the procedure is rapid (75 samples per hour). Albumin influences the measurement, but for concentrations greater than or equal to 35 g/L this was not a serious problem. Normal and diabetic populations can be clearly discriminated (p less than 0.001). The test detected 25 (84%) of the 30 untreated diabetics studied and gave four false positives (8%). The results correlate well with those for glucose in plasma of fasting subjects (r = 0.87) and for hemoglobin A1 (r = 0.80).

Adult↗