Biomedical subjects
I Fraser
Publications and source records attributed to I Fraser.
Health centers and hospital partnerships: a nucleus of community networks.
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Ambulatory care and healthcare reform.
The escalating costs of inpatient care have resulted in the increased utilization of outpatient facilities and home care. As the sites of care proliferate, the system of healthcare delivery must be integrated so that healthcare provision is both cost-effective and safe.
Macrophages in tissues and in vitro.
Macrophages have specialized functions in different tissue microenvironments such as lymphohaemopoietic organs and the nervous system. Recently, progress has been made in defining cellular and molecular properties of isolated and tissue macrophages in the developing and adult animal.
Infantile hypertrophic pyloric stenosis.
This is a world-wide disease, more common in Caucasians and probably on the increase. The aetiology remains very poorly understood. Presentation is between 2 and 8 weeks with vomiting, classically projectile, in an otherwise well hungry child. The diagnosis can confidently be made in most cases by a careful test feed; ultrasound and barium meal examinations are only required for difficult cases. Intravenous fluid replacement is essential prior to surgery and 24 h or longer may be required to correct acid base disturbances and enable safe general anaesthesia. Pyloromyotomy (Ramstedt's operation) remains the only satisfactory treatment, our mortality rate for this is 0.4%. Occasional vomits occur postoperatively in over half of patients but we are sceptical of the value of graded postoperative feeding regimens. There are no known long-term sequelae to surgery and this remains a most rewarding paediatric surgical condition to treat.
Renal failure due to cholesterol emboli.
Renal failure due to cholesterol embolisation is an uncommonly recognised condition. It is usually associated with severe aortic atherosclerosis and in most cases follows a vascular event, such as angiography, vascular surgery, or aneurysm rupture. We report nine patients, all males, who presented to our unit. Six patients survived the initial event, although two died six and eight weeks later. This report emphasises that, although this condition has a high mortality, long term survival is not a rare event.
Early adaptations in blood substrates, metabolites, and hormones to prolonged exercise training in man.
This study was designed to investigate the effect of short-term, submaximal training on changes in blood substrates, metabolites, and hormonal concentrations during prolonged exercise at the same power output. Cycle training was performed daily by eight male subjects (VO2max = 53.0 +/- 2.0 mL.kg-1.min-1, mean +/- SE) for 10-12 days with each exercise session lasting for 2 h at an average intensity of 59% of VO2max. This training protocol resulted in reductions (p less than 0.05) in blood lactate concentration (mM) at 15 min (2.96 +/- 0.46 vs. 1.73 +/- 0.23), 30 min (2.92 +/- 0.46 vs. 1.70 +/- 0.22), 60 min (2.96 +/- 0.53 vs. 1.72 +/- 0.29), and 90 min (2.58 +/- 1.3 vs. 1.62 +/- 0.23) of exercise. The reduction in blood lactate was also accompanied by lower (p less than 0.05) concentrations of both ammonia and uric acid. Similarly, following training lower concentrations (p less than 0.05) were observed for blood beta-hydroxybutyrate (60 and 90 min) and serum free fatty acids (90 min). Blood glucose (15 and 30 min) and blood glycerol (30 and 60 min) were higher (p less than 0.05) following training, whereas blood alanine and pyruvate were unaffected. For the hormones insulin, glucagon, epinephrine, and norepinephrine, only epinephrine and norepinephrine were altered with training. For both of the catecholamines, the exercise-induced increase was blunted (p less than 0.05) at both 60 and 90 min. As indicated by the changes in blood lactate, ammonia, and uric acid, a depression in glycolysis and IMP formation is suggested as an early adaptive response to prolonged submaximal exercise training.
Expression of a divalent cation-dependent erythroblast adhesion receptor by stromal macrophages from murine bone marrow.
Stromal macrophages in haemopoietic organs express novel surface receptors that are implicated in trophic interactions with developing blood cells. Macrophages isolated from foetal liver bind erythroblasts (Eb) by a divalent cation-dependent receptor (EbR), whereas stromal macrophages in adult bone marrow and lymphoid organs express a lectin-like receptor, sialoadhesin, which interacts with sialylated structures on sheep erythrocytes and murine haemopoietic cells. In order to learn more about the regulation of these haemagglutinins, we examined binding of Eb by stromal macrophages that had been isolated from adult murine tissues or generated in Dexter-type cultures of bone marrow. Macrophages were purified from bone marrow by collagenase digestion, adherence to a substratum and detachment of clustered haemopoietic cells, and tested for their ability to bind Eb from foetal liver or anaemic adult spleen. Freshly isolated bone marrow macrophages bound Eb mainly by a divalent cation-dependent activity that was not inhibited by neuraminidase treatment of Eb or by specific anti-sialoadhesin monoclonal antibodies, although these macrophages express sialoadhesin and Eb bear a potential ligand for this receptor. Macrophages obtained by digestion from other adult lymphoid tissues also bound Eb by a divalent cation-dependent activity, whereas blood monocytes and lavaged peritoneal macrophages failed to do so. Peritoneal macrophages could be induced to express high levels of sialoadhesin by cultivation in homologous mouse serum, but such macrophages did not acquire sialoadhesin-independent EbR activity.(ABSTRACT TRUNCATED AT 250 WORDS)
Positive end-expiratory pressure vs T-piece. Extubation after mechanical ventilation.
Because T-piece breathing may impair oxygenation, the best airway pressure from which to extubate ventilated patients is controversial. We compared the effects of extubation after 1 h of either CPAP 5 and T-piece/ZEEP. Once weaned from mechanical ventilation and breathing spontaneously, 106 patients were randomized to 1 h CPAP or 1 h T-piece/ZEEP, following which patients were extubated and mask O2 administered. No significant difference existed between groups in age, sex, HR, BP, FIO2, PaCO2 or PaO2. However, P(A-a)O2 was significantly greater at 120 min in the CPAP group. Within the CPAP group, P(A-a)O2 was also significantly worse at 120 vs 0 min. Nineteen T-piece patients showed improved P(A-a)O2 at 120 min compared with only ten CPAP patients. Three CPAP and two T-piece patients subsequently required reintubation. This study demonstrates that use of a T-piece dose not impair arterial oxygenation and may in fact be superior to direct extubation from CPAP 5.
Medicaid shortfalls and total unreimbursed hospital care for the poor, 1980-1989.
This article examines the relationship between Medicaid payments and hospital costs from 1980 through 1989, using data from the American Hospital Association's Annual Survey of Hospitals. It finds that payments covered about 90% of Medicaid hospital costs until 1985, then declined to 78% in 1989. Together, Medicaid shortfalls ($4.2 billion) and unsponsored care ($8.9 billion) accounted for $13.1 billion in unreimbursed hospital costs in 1989. Most of the recent growth in unreimbursed hospital cost incurred in care for the poor is now caused by rising Medicaid shortfalls rather than increases in unsponsored care. While Medicaid shortfalls accounted for about one-fifth of unreimbursed care for the poor in 1980, they accounted for a third in 1989.
Bone marrow donor registries: discordance in HLA frequencies between donor and recipient populations.
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Double-blind study of dilevalol and captopril, both in combination with hydrochlorothiazide, in patients with moderate to severe hypertension.
Sixty-one patients (41 men, 20 women) aged 29-73 years, with moderate to severe hypertension, were enrolled in a multicentre study to compare the efficacy, safety, and tolerability of dilevalol (D) and captopril (C). At the end of the baseline period, supine diastolic blood pressure (SuDBP) was 105-140 mm Hg on hydrochlorothiazide (HCTZ) 25 mg once daily and placebo t.i.d. Patients were randomly assigned to D + HCTZ (n = 29) or C + HCTZ (n = 32) and entered phase II titration of D (100-800 mg b.i.d.) or C (12.5 mg b.i.d. to 50 mg t.i.d.). If SuDBP was greater than 99 mm Hg, hydralazine was added (25 mg once daily to 50 mg b.i.d.). If SuDBP was less than or equal to 99 mm Hg, patients entered phase III, a 3-month maintenance period. Demographic profiles were not significantly different between the two groups. Baseline supine BP (mean +/- SEM) was similar in the two groups (D + HCTZ: 182 +/- 3/112 +/- 1; C + HCTZ: 179 +/- 4/113 +/- 1 mm Hg), as was baseline standing BP (D + HCTZ: 175 +/- 3/114 +/- 2; C +/- HCTZ: 173 +/- 4/113 +/- 1 mm Hg). At the end of phase II, there were no significant differences between treatments with respect to the changes in BP from baseline.(ABSTRACT TRUNCATED AT 250 WORDS)
Training-induced alterations in muscle glycogen utilization in fibre-specific types during prolonged exercise.
Using the glycogen depletion technique, we have examined utilization of specific fibre types during prolonged submaximal exercise to investigate the recruitment pattern employed by the central nervous system to sustain force generation in the face of a progressive glycogen depletion. Six male subjects (Vo2 max, 52.8 +/- 2.5 mL.kg-1.min-1, mean +/- SE) cycled at 59% of pretraining Vo2 max (the same absolute power output) for 99.5 +/- 6 min on two occasions, before training and after 10-12 days of intensive training, involving 2 h of cycling per day. Prior to the training, glycogen concentration during exercise in the type I and type IIA fibres of the vastus lateralis muscle as measured by microphotometric techniques was progressively reduced during exercise. The pattern of depletion in both of these fibre types was parallel and showed an early marked depletion amounting to 51 (p less than 0.05) and 35% (p less than 0.05) in the type I and type IIA fibres, respectively, during the first 15 min of exercise. At the end of exercise, glycogen levels in type I and type IIA fibres were reduced to 9 and 44% of initial levels, respectively. In contrast, glycogen concentration in type IIB fibres was not significantly (p less than 0.05) altered throughout the exercise. Following training, a pronounced glycogen sparing occurred that was conspicuous in only the type I and type IIA fibres, which was most pronounced during the first 15 min of the exercise. Similar to pretraining, glycogen concentrations in type IIB fibres were unaffected by either exercise or training.(ABSTRACT TRUNCATED AT 250 WORDS)
Danazol and hepatic neoplasia: a case report.
Although hepatic side-effects of danazol are well known, the occurrence of hepatic tumours is not well documented. We report a case of hepatocellular adenoma occurring in a 35-year-old woman with endometriosis who had been taking danazol over a three year period.
Labour induction with low dose PGE2 vaginal gel: result of an Australian multicentre randomized trial.
An open-label, parallel, randomized study was conducted in 6 Australian hospitals involving 320 women near term who required induction of labour. Labour induction with 1 or 2mg of PGE2 in a vaginal triacetin gel repeated if necessary at 6 hours was compared to induction by amniotomy and intravenous oxytocin. Analysis of the 2 groups confirmed matching with regards demographic and clinical data. A significantly longer and more variable mean induction to onset of established labour interval was recorded in the PGE2 group (6.7 +/- 4.8 versus 2.0 +/- 1.1 hours. (p less than 0.001). The mean period of established labour was also longer (8.1 versus 6.0 hours, p less than 0.001) in the PGE2 group. However, 48% of PGE2 treated patients versus 29% oxytocin treated patients (p less than 0.01) were recorded as not experiencing strong contractions. Twelve hours after induction 65% of the PGE2 group and 93% of the oxytocin group were in established labour; 24% of the PGE2 treated group required subsequent augmentation with oxytocin. Spontaneous delivery occurred in 69% of PGE2 treated women and 62% of those treated with oxytocin (N.S.). Analgesic requirements were not statistically different between the groups. Fewer fetal heart rate abnormalities were recorded in the PGE2 treated group (p less than 0.02). No serious and only minimal adverse events were recorded in either treatment group.
Medicaid: repairing the safety net.
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Pathogenesis of hypotension in septic shock: correlation of circulating phospholipase A2 levels with circulatory collapse.
Circulating phospholipase A2 (PLA2) has been recognized as a mediator of circulatory collapse in experimental endotoxic shock. To assess the role of serum PLA2 in septic shock in man, we determined serum PLA2 profiles in a prospective study in 12 patients with septic shock. During the hypotensive phase of sepsis, serum PLA2 levels were consistently elevated as high as 33,428 U/ml (normal range 115 +/- 12 [SE]; n = 101). In all 12 patients, PLA2 levels correlated directly with the magnitude and duration of circulatory collapse (p less than .001), with a progressive fall of serum PLA2 levels during convalescence. In contrast, serum PLA2 levels in patients with cardiogenic shock secondary to myocardial infarction remained low. In pancreatitis, PLA2 levels paralleled fluctuations of serum amylase and lipase, whereas in septic shock without pancreatic involvement, PLA2 changes were discordant with changes in pancreatic enzymes. As well, septic shock serum PLA2 failed to crossreact by radioimmunoassay with antiserum against human pancreatic PLA2. These data are consistent with an extrapancreatic source of intravascular PLA2 release during sepsis. Since endogenous serum PLA2 levels correlate directly with the magnitude of hypotension in both experimental endotoxic shock and clinical septic shock, and since parenteral administration of purified exogenous PLA2 reproduces hypotension in experimental models, we conclude that high levels of intravascular PLA2 may contribute similarly to the circulatory collapse in septic shock in man.
Promoting worker health insurance.
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