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Biomedical subjects

A Cole

Publications and source records attributed to A Cole.

At least 19 recordsLinked to original sources
PubMed1992

Intramuscular wire electromyography of the subscapularis.

The action of the subscapularis muscle is an important component in maintaining shoulder stability. Because of its relative inaccessibility, there have been few electromyographic (EMG) studies of its normal patterns of activity. The subscapularis is innervated by two or more distinct nerves, and therefore the upper and lower parts of the muscle may have different functional roles depending on the position of the humerus. The purpose of this study was to develop safe, reproducible insertion paths to the upper and lower parts of the subscapularis. Six subjects with no previous history of shoulder injury were evaluated. The paths of insertion were designed based on previous anatomical studies as well as dissections. Two pairs of intramuscular wire electrodes were inserted: one directed toward the upper subscapularis and one toward the lower subscapularis. Electrode locations were confirmed using posteroanterior and lateral radiographs and through electrical stimulation. EMG data were recorded during isometric internal rotation exercises with the humerus in 0 or 90 degrees abduction. Significant differences were observed in the EMG activity recorded from the two pairs of electrodes. The EMG activity of the upper subscapularis either remained the same or decreased in going from 0 to 90 degrees abduction, while that of the lower subscapularis increased. The observed differential response confirmed that the electrodes were in different parts of the subscapularis. These preliminary results suggest that in future EMG studies, the subscapularis should be considered as at least two independent muscle units.

Electric Stimulation↗
PubMed1990

Possible protein binding displacement interaction between glibenclamide and metolazone.

The effects of metolazone on the protein binding of glibenclamide were studied. It was found that increasing metolazone concentrations up to 100 ng/ml had no significant effect on the protein binding of glibenclamide studied at 10 micrograms/ml. Metolazone is unlikely to cause a clinically significant increase in the free fraction of glibenclamide in patients receiving both drugs.

Aged↗
PubMed1990

Hostility, hopelessness and deliberate self-harm: a prospective follow-up study.

Sixty-one consecutive patients who presented following an episode of deliberate self-harm (DSH) were assessed on a number of variables, including measures of hopelessness and hostility. Attempts were made to follow all of the patients. Those who were known to have had a further episode of DSH had significantly higher levels of hopelessness and intropunitive hostility after the index episode than those who did not repeat. The question of vulnerability to DSH is discussed as well as the possibility of using measures of hopelessness and intropunitive hostility to identify those at greater risk of repetition.

Adolescent↗
PubMed1990

Folie à deux and dementia.

Folie à deux has been infrequently reported in dementia patients. A case is described in which both partners with folie à deux suffered from an Alzheimer type dementia. The development and management of folie à deux in dementia is discussed.

Aged↗
PubMed1989

Comparison of the biological effects of selected 5,8-dideazafolate analogues with their 2-desamino counterparts.

Three new 5,8-dideaza analogues of folic acid devoid of an amino group at position 2 have been prepared by using synthetic routes patterned after earlier methodologies. They were 2-desamino-5,8-dideazaisofolic acid, 2b, 2-desamino-10-thia-5,8-dideazafolic acid, 2c, and 2-desamino-10-oxa-5,8-dideazafolic acid, 2d. These compounds were found to be 4-6-fold more cytoxic toward L1210 leukemia cells than their 2-NH2 counterparts and to be poor inhibitors of mammalian thymidylate synthase. However, they were only 1.5-3-fold less inhibitory toward dihydrofolate reductase than the analogous compounds containing a 2-NH2 group. The known thymidylate synthase inhibitors 2-desamino-10-propargyl-5,8-dideazafolic acid and 10-propargyl-5,8-dideazafolic acid were included in this study for purposes of comparison.

Animals↗
PubMed1988

Ultrastructural study of mitochondrial damage in CHO cells exposed to hyperthermia.

A unique direct-view stereo electron microscope technique was used to visualize the structure and three-dimensional distributions of mitochondria in CHO cells in situ following hyperthermic treatments. Aberrations induced by various heating regimens were recorded. The protocol included a trypsin digestion that may have enhanced the expression of the initial heat damage. The developed damage was observed as increasing levels of mitochondrial distortion, swelling, and dissociation. Minimal damage was induced at 42 degrees C for exposures of up to 4 h, while significant damage was induced at 43 degrees C for exposures of more than 30 min and at 45 degrees C for exposures of more than 10 min. For moderate exposures, a partial recovery of mitochondrial integrity was observed when the heat treatment was followed by incubation at 37 degrees C for 24 h. Mitochondrial damage was related to the heat dose in that increasing treatment temperature resulted in greater damage, but when compared to cell survival the damage did not parallel cell killing under all time-temperature conditions.

Animals↗
PubMed1985

Cell surface antigens of Bordetella pertussis.

Cell surface-specific radiolabelling techniques, monoclonal antibody analyses, and chemical and physical isolation of cell fractions were used to study the surface of B. pertussis cells. Four surface specific proteins were identified by radioiodination and monoclonal antibody techniques. These included the filamentous hemagglutinin (FHA), and three outer membrane proteins-OMP91, OMP18 and OMP15. Membrane blebs were isolated from culture supernatants and shown to contain LPSII, pertussis toxin (PT), FHA, OMP91, and OMP18, but not OMP15. The level of LPS I in blebs appeared to be reduced from the level in cell envelopes. Bleb fractions contained enzymatically active adenylate cyclase (AC), and biologically active dermonecrotic toxin (DNT) and PT. Blebs were also toxic for mice, even when heated to 80 degrees C for 30 minutes. To explain these data, we propose that membrane blebs comprise an effective toxin delivery system, and that the cell surface of B. pertussis is composed of at least two domains.

Adenylate Cyclase Toxin↗
PubMed1979

The use of balloon-tipped electrodes for permanent cardiac pacing.

A new balloon-tipped ventricular endocardial electrode for permanent artificial cardiac pacing is described. Following transvenous insertion of the electrode to the right ventricular apex, the distal balloon is inflated with contrast material in order to wedge the electrode tip between or beneath trabeculae and prevent displacement. fifty-nine electrodes were implanted, including a second generation type incorporating a wedge tip as well as the balloon. The incidence of displacement was 17% with 10% of cases being early, and 7% late. Early in the series, 50% Urografin was used to inflate the balloon and this resulted in premature deflation and early electrode displacement in two of the nine patients. When the concentration of Urografin was reduced, the balloon remained inflated for a longer period and the incidence of early displacement was reduced to 8%. However, there was still a late displacement of 8%. Only one wedge-tipped balloon electrode displaced. This electrode had a faulty sealing mechanism and the balloon could not be adequately inflated. There was a 3% incidence of early and a 3% incidence of late threshold problems with the electrode. However, name of the wedge-tipped balloon electrodes exhibited this problem. It was concluded that this new electrode did not fulfill its objectives. The total electrode failure rate, including displacements and episodes of high threshold was approximately 24%.

Aged↗
PubMed1976

A metallurgical examination of fractured stainless-steel ASIF tibial plates.

Between 1970 and 1973 99 tibial fractures were treated by rigid internal fixation with ASIF plates. The fractures were all regarded as sufficiently stable for exercise without weight bearing, thus needing no additional external support during the healing period. Four of the plates broke late in the healing period, after the onset of weight bearing. These fractures had some degree of delayed union with slight resorption of the bone ends, resulting in cyclical bending of the plate. Examination of 2 of the fractured plates by scanning electron microscopy, electron microprobe analysis and optical metallography revealed that the primary cause of plate fracture was fatigue. There was no evidence that corrosion fatigue or inclusion content were factors leading to plate fracture.

Adult↗