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Biomedical subjects

S Maxwell

Publications and source records attributed to S Maxwell.

At least 73 records · Page 4Linked to original sources
PubMed1993

The impact of a short course of three lipid lowering drugs on fat oxidation during exercise in healthy volunteers.

We examined the impact of three lipid lowering drugs on fat oxidation during a 120 minute treadmill walk, at an exercise intensity of 50% maximal oxygen uptake (VO2 max). Subjects (N = 24) were healthy male volunteers with normal serum chemistry, assigned to three groups (n = 8). Group A received simvastatin 20 mg twice daily, Group B received gemfibrozil 600 mg twice daily, Group C received acipimox 600 mg twice daily. Each subject performed two 120 minute walks, once with drug, and once with placebo (4 days treatment plus a final dose on the morning of the exercise trial). Treatment order was reversed for half of each group. Compared to placebo, simvastatin treatment, had no impact on fat oxidation (40.9 +/- 8.6% vs 40.9 +/- 9.7%), or on plasma concentration of free fatty acids (FFA), glycerol or glucose. Treatment with gemfibrozil, showed lower fat oxidation (32.3 +/- 13.9% vs 39.7 +/- 7.9%), and lower plasma concentrations of FFA and glycerol, but differences did not reach significance at the 0.05 level. Acipimox treatment, produced significantly lower fat oxidation (36.9 +/- 12.8% vs 50.2 +/- 16.1%, P = 0.011), and lower plasma concentrations of FFA and glycerol (P = < 0.0001 and P = < 0.0001, respectively). Plasma glucose showed a trend toward lower values with acipimox (P = 0.088). These data demonstrate that selective lipid lowering drugs can reduce fat availability for exercise metabolism, placing increased demands on carbohydrates which may reduce exercise tolerance.

Adult↗
PubMed1993

The effect of mechanical damping loads on disabling action tremor.

Patients with severe action tremor have uncontrollable, relatively rapid oscillatory motion super-imposed on otherwise useable slower voluntary motor activity. Because a mechanical damper produces an opposing force proportional to velocity, applying damping loads to tremorous limbs should attenuate the (high-velocity) tremor component of movement while permitting the slower purposeful portion to proceed relatively unopposed. In this study, the effect of upper extremity damping in three degrees of freedom was examined in 10 patients with cerebellar action tremor due to multiple sclerosis or traumatic brain injury. Variable amounts of damping were applied by prototype energy-dissipating orthoses which generated resistive viscous loads by means of computer-controlled magnetic particle brakes. All patients experienced statistically and functionally significant tremor reduction with the application of damping.

Adult↗
PubMed1993

A study of the consequences of malarial infection in pregnant women and their infants.

An outline is given of a field research study to be undertaken in Malawi to investigate the pattern and consequences of malaria in pregnancy and infants. The central question to be investigated is whether babies born to anaemic mothers in malarious areas are at increased risk of developing anaemia or altered risk for morbidity from malaria or develop anaemia in the first year of life. The framework for the case control and cohort study to be undertaken is outlined.

Anemia↗
PubMed1991

A comparison of the metabolic effects of flosequinan and propranolol in patients with non-insulin-dependent diabetes mellitus.

The effects of steady-state flosequinan, a new peripheral vasodilator, and propranolol on glucose tolerance and plasma lipids in 22 non-insulin-dependent diabetics were investigated in a randomized double-blind placebo-controlled, three-way crossover trial. Flosequinan produced no impairment of glucose tolerance compared with placebo. Propranolol produced significant increases in fasting plasma glucose (P less than 0.01) and increases in the area under the glucose tolerance curve (P less than 0.05) compared to placebo. No significant effects on cholesterol levels were seen on either treatment but triglyceride levels were significantly elevated on propranolol compared with placebo (P less than 0.01). These data suggest that flosequinan, used in therapeutic dosage, has no adverse metabolic effects on the non-insulin-dependent diabetic and this may be an advantage for a drug used in the treatment of hypertension or congestive heart failure.

Adult↗
PubMed1990

Two outbreaks of Legionnaires' disease in Bolton Health District.

In 1988, there were two outbreaks of legionellosis in Bolton Health District. Altogether 37 cases of Legionnaires' disease and 23 cases of non-pneumonic legionellosis were identified. Twenty-five patients with Legionnaires' disease were associated with an engineering plant, 4 with Bolton town centre, and 8 with both the plant and town centre. Twenty-two people with non-pneumonic legionellosis were linked with the engineering plant and one with the plant and the town centre. A case-control study carried out among 37 employees with legionellosis and 109 control subjects at the plant showed that infection was associated with one of the 15 cooling towers on the site. Legionella pneumophila indistinguishable by serological and genetic typing methods was isolated from this cooling tower and from sputum samples from two patients. In the town centre, no one tower was linked with infection and L. pneumophila was not cultured from any of the nine towers identified. Control measures were implemented and to date there have been no further cases of legionellosis associated with Bolton Health District.

Adult↗
PubMed1989

Endocarditis due to Streptococcus morbillorum.

Two cases of endocarditis due to Streptococcus morbillorum are described. Neither patient had any known history of valvular disease. These are believed to be the first such reported cases in the U.K. In the first case, previous anal surgery and, in the second, drainage of a dental abscess and extraction of a tooth are the likely procedures which initiated endocarditis. The first case is of further interest in that the incriminated strain showed marked tolerance to beta-lactam antibiotics. A combination of penicillin with gentamicin was shown to be required in order to give satisfactory bactericidal activity in vitro.

Adult↗
PubMed1988

A second generation microcomputer controlled binding system for alpine skiing research.

In the study of sports biomechanics, alpine skiing injuries have always demanded significant attention. In order to aid in understanding the loading phenomena associated with alpine skiing, a new research binding system has been designed which enables both the recording of boot loading data and actively controlled release of the skier's boot from the ski. The new research binding system consists of three hardware components, a dynamometer which senses all six load components at the boot/ski interface, an electromechanical device capable of releasing the boot from the ski, and a new general purpose microprocessor-based data acquisition and release control module. Constructed integrally with the dynamometer, the release mechanism is activated by electrical command from the control module. The mechanical and electrical design features of the dynamometer/release mechanism as well as important features of the hardware and software of the data acquisition and control module are briefly discussed. The system has been tested both in the laboratory and on the ski slopes. The emphasis of this paper is on the boot loading data acquired through field testing and observations on the loading environment during common recreational skiing maneuvers. Through analysis of the data, insight into both the style and safety aspects of alpine skiing is gained.

Athletic Injuries↗
PubMed1987

A comparison of external and self-instructional teaching formats with mentally retarded adults in a vocational training setting.

A theory recently proposed by Whitman postulates that self-instructional training procedures should have special utility for low ability individuals. Although past studies have shown that self-instructional training programs can be employed to improve the performance of mentally retarded individuals in work situations, research has not examined whether this training format is superior to external instruction. To test Whitman's theory, mentally retarded adults were taught to perform a complex sequencing task through one of two training formats: self-instruction or external instruction. Performance was evaluated through the examination of accuracy measures obtained during training, maintenance, and generalization assessments. Results indicated that participants receiving self-instructional training were able to achieve and sustain a higher level of performance than participants receiving external instruction. While self-instructionally trained subjects also showed superior performance on the generalization assessment, these results were not statistically significant. Secondary analyses revealed that higher ability participants, self-instructionally trained participants, and participants who reached criterion on the training and generalization tasks self-verbalized more frequently during the various assessments. In contrast to prediction, there was no significant difference in the length of time required to train individuals in the two instructional groups.

Adolescent↗
PubMed1985

Synthesis and binding of lactose-specific lectin by isolated lung cells.

Neonatal maturation of alveolar structure in rat lung temporally coincides with the peak activity of a beta-galactoside-specific endogenous lung lectin of the type that has been linked to developmental processes in other tissues. To learn more about the lung lectin we examined four cell types for their ability to synthesize and bind the lectin. Cultured lung fibroblasts and pulmonary artery endothelial cells synthesized and bound the lectin, alveolar macrophages bound but did not synthesize it, and alveolar epithelial type II cells neither bound nor synthesized it. Pulmonary macrophages made a different lactose-binding protein that did not agglutinate or bind trypsin-treated red blood cells, a property of lung lectin that is the means of its assay.

Amino Acids↗
PubMed1985

Postnatal development of alveoli. Regulation and evidence for a critical period in rats.

In many species, including humans, pulmonary alveoli are formed after birth by septal subdivision of the large gas-exchange saccules present at birth. In rats septation occurs mainly between the 4th and 14th postnatal days (Burri, P. H. 1974. Anat. Rec. 180:77-98), but little is known about the regulation of this process. We found that dexamethasone (0.1 micrograms daily) given to rats from age 4 to 13 d markedly impaired saccule septation to at least age 60 d and also diminished the extent of the increase of alveolar surface area (Sa). Underfeeding from birth to age 14 d did not diminish saccule septation but did result in diminished Sa. We conclude dexamethasone-treated rats have a critical period during which the gas-exchange saccules present at birth must be subdivided. Since Sa increased in dexamethasone-treated rats without a change in alveolar size, and, the enlargement of Sa was diminished in underfed rat pups without a deficit of saccule septation, we postulate new alveoli were formed by means other than septation of the large gas-exchange saccules present at birth. Furthermore, these various means of forming alveoli, and hence of increasing Sa, were differently regulated: dexamethasone decreased the enlargement of Sa brought about by both septation of the gas-exchange saccules present at birth and by other, as yet unidentified, means of forming alveoli; underfeeding did not diminish Sa increases produced by saccule septation but did decrease the extent of Sa enlargement due to the other means of forming alveoli.

Animals↗
PubMed1984

The gag-mos hybrid protein of ts110 Moloney murine sarcoma virus: variation of gene expression with temperature.

A NRK cell clone (6m2 cells) infected with ts110 Moloney murine sarcoma virus (MuSV) produce a gag-mos protein, P85gag-mos, and a truncated gag protein of Mr 58,000d termed P58gag. The gag-mos protein is produced from a 3.5-kb mRNA whereas the gag protein is made from a 4.0-kb mRNA. It has been proposed that the 3.5-kb RNA is produced from the 4.0-kb RNA by a splicing mechanism (R. P. Junghans, E. C. Murphy, Jr., and R. B. Arlinghaus (1982) J. Mol. Biol. 161, 229-255). The results presented here provide further support for this model. The expression of the 3.5-kb RNA and the gag-mos protein increased as the temperature at which 6m2 cells were maintained was lowered from 39 to 28 degrees. This increase coincided with a decrease in both the 4.0-kb RNA and its product P58gag. The optimum temperature for syntheses of both the gag-mos mRNA and its protein was found to be 28 degrees. Consistent with the increase in the level of the gag-mos protein is the increase in the protein kinase activity associated with P85gag-mos and the degree of morphological transformation of 6m2 cells. Thus, the level of P85gag-mos within 6m2 cells is directly proportional to the degree of cell transformation and the amount of the kinase activity associated with the gag-mos protein, providing convincing evidence that P85gag-mos plays a direct role in the neoplastic transformation of these cells.

Animals↗
PubMed1983

Bacteraemia with upper gastrointestinal endoscopy--a reappraisal.

To assess the risk of infective endocarditis for susceptible patients having upper gastrointestinal (GI) endoscopy, we have prospectively studied the incidence, level, duration and source of endoscopy-related bacteraemia and the microorganisms involved. Blood was drawn for aerobic and anaerobic culture and pour plate estimation from 50 patients undergoing upper GI endoscopy. Blood cultures were positive in two patients with the isolation of Streptococci and other oropharyngeal organisms during and 5 min after endoscopy. Pre-endoscopy salivary cultures in both patients grew Streptococci identical to those isolated from the blood; pour plates were negative. We conclude that though the risk of infective endocarditis after upper GI endoscopy is probably very low, the finding of a 4% incidence of transient low-level bacteraemia of oropharyngeal origin argues for antibiotic prophylaxis for susceptible patients.

Adolescent↗