Search PubMed⌕ Search

Biomedical subjects

D Martin

Publications and source records attributed to D Martin.

At least 505 records · Page 28Linked to original sources
PubMed1993

Infection of implantable cardioverter defibrillator systems: a preventable complication?

In a consecutive series of 164 patients undergoing primary implantation of an implantable cardioverter defibrillator (ICD), two patients died in the hospital (1.2%) and early system infection developed in one patient requiring explantation of the device (0.61%). Late infection developed in one additional patient (0.61%) 7 months after transvenous ICD implantation, and was thought to be due to a recent intravascular catheterization. Symptomatic generator pocket hematomas developed in three patients, two of which were treated by simple evacuation and one with temporary generator explanation and subsequent reimplantation of the unit in a new pocket. No infection developed in these three patients during follow-up. Generator erosion without obvious system infection developed in a fourth patient. Guidelines for the prevention of infection in ICD systems are presented.

Defibrillators, Implantable↗
PubMed1993

Rigorous exercise training increases superoxide dismutase activity in ventricular myocardium.

Controversy exists as to the effect of endurance training on myocardial antioxidant enzyme activity. These experiments sought to clarify this issue by examining antioxidant enzyme activities in the rat ventricular myocardium in response to different intensities and durations of exercise training. Female Fischer-344 rats (120 days old) were assigned to either a sedentary control group or one of nine exercise training groups. Animals were exercised on a motorized treadmill for 10 wk; combinations of three durations (30, 60, and 90 min/day), and three levels of exercise intensity (low, moderate, and high) were studied. Exercise training did not alter (P > 0.05) citrate synthase, catalase, or glutathione peroxidase activities in the right or left ventricle. In contrast, high-intensity exercise (all durations) and moderate-intensity exercise (90 min/day) resulted in a significant increase (P < 0.05; +28-30%) in right ventricular superoxide dismutase (SOD) activity. Similarly, high-intensity exercise training (all durations) resulted in a significant elevation (P < 0.05; +14-26%) of left ventricular SOD activity. Furthermore, low- and moderate-intensity exercise training of long duration (i.e., 60-90 min/day) resulted in significant increases (P < 0.05; +10-23%) in left ventricular SOD activity. These data support the hypothesis that high-intensity exercise (> or = 30 min/day) or moderate-intensity exercise of long duration (> or = 60 min/day) is effective in upregulating SOD activity in the ventricular myocardium.

Animals↗
PubMed1993

Exercise and glucocorticoid-induced diaphragmatic myopathy.

We tested the hypothesis that a chronically active muscle, such as the rat diaphragm, would be more resistant to glucocorticoid-induced myopathy than a less active locomotor skeletal muscle (plantaris). Furthermore, we sought to determine whether endurance exercise could antagonize the glucocorticoid-induced atrophy in the diaphragm. Rats were assigned to one of seven experimental groups (n = 10 per group) and injected daily over a 10-day period with either a sham solution or prednisolone acetate: group 1: control; sedentary and sham injected; group 2: control; exercise trained and sham injected; group 3; sedentary; prednisolone (0.5 mg.kg-1 x day-1); group 4: sedentary; prednisolone (1.0 mg.kg-1 x day-1); group 5: sedentary; prednisolone (2.0 mg.kg-1 x day-1); group 6: sedentary; prednisolone (5.0 mg.kg-1 x day-1); group 7: exercise trained; prednisolone (5.0 mg.kg-1 x day-1). Slope differences in the dose-response curves suggest that prednisolone-induced muscle atrophy in the plantaris was more severe than that in the diaphragm. Furthermore, high doses of prednisolone resulted in a differential effect on muscle bioenergetic enzyme activities in the plantaris and diaphragm. Prednisolone treatment (> or = 2 mg.kg-1 x day-1) resulted in a significant reduction in phosphofructokinase activity (expressed as microM substrate.min-1 x mg protein-1) and an increase in 3-hydroxyacyl-CoA dehydrogenase activity in the plantaris muscle. In contrast, prednisolone treatment did not influence phosphofructokinase activity (P > 0.05) in the diaphragm but decreased (P < 0.05) relative citrate synthase activity. Finally, 90 min daily of endurance exercise did not antagonize prednisolone-induced myopathy in either the diaphragm or the plantaris.

Adrenal Glands↗
PubMed1993

Application of indirect ELISA for detection of bovine antibodies against vesicular stomatitis viruses.

Two indirect enzyme-linked immunosorbent assays (I-ELISAs) are described for the detection of bovine serum antibody to the New Jersey (NJ) and Indiana (IN) vesicular stomatitis viruses (VSV). Serum samples at a dilution of 1:200 were incubated with binary ethylenimine-inactivated VSV-NJ and VSV-IN type-specific antigens preadsorbed to microtiter plates. Bound antibodies were detected by a murine monoclonal antibody to bovine IgG1 conjugated with horseradish peroxidase. The performance of each I-ELISA in detecting homotypic and heterotypic antibodies to VSV-NJ and VSV-IN in sequential serum samples from calves experimentally infected with VSV-NJ or VSV-IN was evaluated. The I-ELISAs detected serotype-specific antibodies to either VSV-NJ or VSV-IN in calves infected with the homologous serotype. Homotypic but not heterotypic anti-VSV-NJ antibodies were first demonstrable by the VSV-NJ I-ELISA during the second week postinfection and remained at an elevated level for a period of 11 weeks, with a gradual decrease thereafter. Similar homotypic antibody profiles measured by the VSV-IN I-ELISA in calves inoculated with VSV-IN were observed. The performances of the I-ELISAs were compared using 1,495 microtiter serum neutralization (MTSN) test-negative bovine field sera collected from cattle in Canada (VS free) and 429 samples collected from cattle in the USA and Mexico (VS-epidemic and VS-endemic areas). The diagnostic specificities of the VSV-NJ and VSV-IN I-ELISAs for the Canadian samples relative to the MTSN test results were in the range of 99.8% and 99.7%, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

The stimulatory effect of insulin on diacylglycerol generation in adipocyte membranes from ob/ob mice is impaired by growth hormone.

Physiologically, the action of insulin on carbohydrate and lipid metabolism is opposed by several hormones, including glucocorticoids, glucagon, catecholamines, and pituitary GH. Perhaps least is known about the mechanism(s) involved in the antiinsulin action of GH. Since the generation of diacylglycerol (DAG) appears to be an early event in the insulin-signaling cascade, it was of interest to determine whether GH would interfere with this effect of insulin. Experiments were conducted to determine whether insulin would stimulate the generation of DAG in adipocytes of the obese (ob/ob) mouse, and whether this response could be blocked by the diabetogenic GH derivative S-carboxymethylated human GH (RCM-hGH). Isolated adipocytes of the ob/ob mouse were used for these studies, because unlike normal rodents, the ob/ob mouse responds predictably to the antiinsulin action of GH. Insulin produced a rapid biphasic increase in the amount of DAG in a crude membrane fraction of the adipocytes. The first peak in DAG mass occurred within 5 min of exposure of the cells to insulin, and the second peak occurred after 30 min. The first peak in DAG mass did not occur in adipocytes that had been incubated with pertussis toxin before exposure to insulin. Also, adipocytes isolated from ob/ob mice that had been treated with RCM-hGH failed to respond to insulin with an increase in DAG mass. RCM-hGH blocked both the first and second insulin-induced peaks in DAG mass within 6 h of its administration. This is the time at which ob/ob mouse adipocytes exhibit increased insulin resistance in response to RCM-hGH. Neither exposure to insulin nor treatment with RCM-hGH had any appreciable effect on the fatty acid composition of the DAG present in the adipocyte membranes. These findings are compatible with the idea that GH produces some defect in the insulin-signaling cascade that is proximal to the events that result in the generation of DAG in the adipocyte.

Adipose Tissue↗
PubMed1993

Exercise-induced hypoxaemia in elite endurance athletes. Incidence, causes and impact on VO2max.

Arterial oxygenation is well maintained in healthy untrained or moderately trained individuals during exercise. In contrast, approximately 40 to 50% of healthy elite endurance athletes (cyclists and runners) demonstrate a significant reduction in arterial oxygenation during exercise at work rates approaching VO2max. The mechanism(s) to explain this exercise-induced hypoxaemia (EIH) remain controversial. However, hypoventilation and venoarterial shunt do not appear to be involved. By elimination, this suggests that ventilation-perfusion inequality and/or pulmonary diffusion limitations must contribute to EIH in this population. Theoretical and direct experimental evidence exists to support the notion that both ventilation-perfusion inequality and diffusion disequilibrium contribute to EIH; however, the relative contribution of each factor remains to be determined. In athletes who exhibit a profound EIH, the exercise-induced decline in arterial oxygenation results in a limitation of VO2max. Further, athletes who exhibit EIH at sea level suffer more severe gas exchange impairments during short term exposure to altitude than athletes or nonathletes who do not exhibit EIH at sea level. This finding explains much of the observed variance in the decline in VO2max among individuals during short term altitude or hypoxia exposure.

Exercise↗
PubMed1993

Cognitive risk factors and neuropsychological performance in HIV infection.

Almost all investigations examining the effects of early HIV infection on neuropsychological functioning in homosexual males have excluded subjects with cognitive risk factors such as recreational drug use and head injury. While insuring that results reflect the influence of the virus on cognition, this selection bias limits the ability to generalize findings. Comprehensive neuropsychological evaluations were compared between two groups of homosexual males with a variety of cognitive risk factors. Subjects were 132 HIV seropositive males (108 CDC class II & III and 24 CDC class IVA & IVC2) and 65 HIV seronegative controls. Recreational drug use in the six months prior to exam was found to interact with HIV infection and was associated with selective areas of cognitive decline and a significantly worse overall neuropsychological performance. Although significantly lower functioning in the domains of Verbal Memory and Attention and Speed of Information processing was noted for subjects with CDC class IVA and IVC2 compared to seropositives with CDC class II & III, overall neuropsychological performance was similar in these two groups. At this early stage of HIV infection, we did not find indication of association between neuropsychological performance and decreased immunological status. A history of head injury and recent recreational drug use emerged as primary cognitive risk factors associated with decreased neuropsychological performance. As 50% of our HIV seropositive subjects reported active recreational drug use, this cognitive risk factor in particular may contribute to the appearance of HIV-related cognitive deficits during early stages of HIV infection.

Cognition Disorders↗
PubMed1993

Computer-derived density spectral array in detection of mild analog electroencephalographic ischemic pattern changes during carotid endarterectomy.

The purpose of this prospective study was twofold: 1) to determine the sensitivity and specificity of computer-derived density spectral array in detecting analog electroencephalographic (EEG) ischemic pattern changes during carotid artery cross-clamping in patients undergoing carotid endarterectomy; and 2) to assess the ability of density spectral array to identify such changes in comparison with the degree and type of change seen in the analog EEG ischemic pattern. Sixteen channels of anteroposterior bipolar and two to four channels of referential electroencephalography with four channels of density spectral array were monitored simultaneously during carotid endarterectomy in 103 patients under general anesthesia. Two "observers" interpreted the density spectral array and the analog electroencephalograms, one during and immediately after the operations and the other 6 months after completion of all surgery. Analyses were conducted to establish both the number of patients with analog EEG ischemic changes and the number of ischemia events during carotid artery cross-clamping. Observer A indicated that the density spectral array identified analog EEG ischemic changes in 21 of 29 patients, for a sensitivity of 72% (specificity 99%), whereas Observer B's results showed that the density spectral array identified analog EEG ischemic changes in 16 of 27 patients, for a sensitivity of 59% (specificity 96%). Density spectral array detection of analog EEG ischemic changes based on severity classifications were 61% and 18% in the mild group, 70% and 71% in the moderate group, and 95% in the severe group, indicating a relationship between density spectral array sensitivity and severity of analog EEG ischemic change, with p = 0.02 and p = 0.004 for the two observers. The kappa statistics for observer reproducibility were highly significant, with k = 0.95 for analog EEG ischemic changes and 0.85 for density spectral array changes. It is concluded that density spectral array does not reliably detect mild analog EEG pattern changes of cerebral ischemia and is not a reliable substitute for 16-channel analog EEG monitoring of cerebral ischemia during carotid endarterectomy.

Adult↗
PubMed1993

Los Angeles organ sharing: twenty-six-year report.

1. The Los Angeles Transplant Society and the Regional Organ Procurement Agency of Southern California (ROPA) was established in November 1967. ROPA was the first such organization in the United States. 2. The use of simple cold storage and shipment of kidneys by commercial airline resulted from pioneering concepts developed in the Los Angeles area from 1968-1969. 3. In the 26-year period of ROPA's operation, it has coordinated 8,446 kidney transplants. 4. All kidneys transplanted in 1993 were allocated according to the UNOS point system. 5. Allocating all kidneys under the point system has not significantly disadvantaged either large or small transplant centers in the greater Los Angeles area. 6. Racial distribution of recipients: 13% Black (compared with Los Angeles population of 12% and 6% donor population). Blacks represent 20% of the recipient waiting list. Hispanic recipients were 31% (compared to Los Angeles population of 40% and donor population of 30%). Hispanics comprised 28% of the waiting list. 7. The average waiting times for centers in the Los Angeles area ranged from 14-19.4 months. Transplanted patients waited an average of 16.3-22.1 months. 8. "Required request" had a significant effect on the number of referrals but did not produce a meaningful increase in the number of kidneys transplanted.

Cryopreservation↗
PubMed1993

[Forum: reconstruction of the traumatic thumb. Reconstruction of the thumb by osteocutaneous flaps of the forearm].

The authors present different techniques of thumb reconstruction using osteocutaneous retrograde island forearm flaps. They describe an original thumb reconstruction technique by using the anterior interosseous osteocutaneous retrograde island flap and present two clinical cases. The advantages and disadvantages as well as the indications of this kind of thumb reconstruction procedure are discussed.

Adult↗
PubMed1993

[Agenesis of the corpus callosum and epilepsy. 26 cases].

Agenesis of the corpus callosum is a cerebral malformation diagnosed by CT scan. Beside mental retardation, the most frequent clinical manifestation is epilepsy. In a personal study of 26 cases, the authors analysed the clinical features of epileptic seizures observed with this malformation. They put the stress on the paradoxical presence of generalized seizures.

Abnormalities, Multiple↗
PubMed1993

The submental island flap: a new donor site. Anatomy and clinical applications as a free or pedicled flap.

This paper describes the use of a new island flap based on the submental artery. Previously described cervical flaps have inherent problems ranging from limited mobility to unacceptable donor-site scars, to unpredictable outcomes. The flap design and technique were studied on 20 fresh cadavers and 8 patients who underwent radical neck dissections. The flap was then used successfully for reconstruction of orofacial defects in 8 patients. The flap has a long (up to 8 cm), reliable pedicle, and cutaneous dimensions can reach up to 7 x 18 cm. It can be used as a cutaneous, musculofascial (cervicofascial and platysma), or osteocutaneous flap. This flap has an excellent skin color match and a wide arc of rotation, and can extend to the whole homolateral face, except for a part of the forehead and the whole oral cavity. The anatomy, the technique, and clinical experiences are presented.

Adult↗