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Biomedical subjects

C Bush

Publications and source records attributed to C Bush.

30 records · Page 2Linked to original sources
PubMed1986

Influence of timing of cytotoxic drug treatment on the response of murine clonogenic spermatogonia to X-irradiation.

The enhancement of radiation-induced stem spermatogonial cell killing by three cytotoxic compounds has been investigated using an in vivo clonogenic assay. Drug doses (carmustine (BCNU), 15 mg/kg; cyclophosphamide (CY), 150 mg/kg; procarbazine (PCB), 200 mg/kg) were chosen to kill a high proportion of differentiated spermatogonia but few stem-cells, as assessed by sperm-head counts (SHC) at 29 and 56 days respectively. Drug doses were administered up to 14 days prior to or after local irradiation with 9 Gy of 230 kVp X-rays. BCNU produced a moderate enhancement of damage that was relatively independent of time. Both CY and PCB produced a considerable enhancement of damage especially when administered 1 to 3 days before irradiation. Enhancement in the case of PCB consisted largely of a vertical displacement of the radiation dose-response curves, but with additional evidence for possible changes in slope.

Animals↗
PubMed1986

Protection from procarbazine-induced damage of spermatogenesis in the rat by androgen.

Protection of spermatogenesis from cytotoxic drug-induced damage has been investigated in the rat. Complete germinal aplasia was observed at 8 and 11 weeks after four doses of procarbazine hydrochloride administered weekly (150 mg/kg, first dose; 100 mg/kg, 3 subsequent doses). Pretreatment of rats for 6 weeks plus continued treatment during procarbazine administration with testosterone enanthate, 240 micrograms/100 g body weight, resulted in a marked protection of spermatogenesis. A mean of 22% of seminiferous tubule cross-sections at both 8 and 11 weeks exhibited spermatogenesis, and developing spermatids were observed in 60% of these repopulating tubules at the later time. These results provide evidence that protection of spermatogenesis during chemotherapy may be achieved by androgen treatment.

Androgens↗
PubMed1985

A controlled evaluation of paraspinal EMG biofeedback in the treatment of chronic low back pain.

Sixty-six chronic low back pain sufferers were randomly divided into three groups. Following individual assessments consisting of psychological questionnaires, pain monitoring, and measurement of paraspinal electromyogram (EMG), one group received paraspinal EMG biofeedback and another a placebo treatment. The third group received no intervention. Two further assessments were carried out on all groups immediately after treatment and at a 3-month follow-up. All groups showed significant reduction in pain, anxiety, depression, and paraspinal EMG following treatment and at follow-up, but there were no differences between groups. A regression analysis failed to identify subjects' characteristics that predicted positive outcome in the biofeedback group. However, high scores on the Evaluative scale of the McGill Pain Questionnaire and high hypnotizability were significant predictors of positive outcome for the placebo group. It is concluded that paraspinal EMG biofeedback is not a specific treatment for chronic low back pain in a nonhospitalized population.

Adult↗
PubMed1984

Hemodynamic correlates for timing intervals, ejection rate and filling rate derived from the radionuclide angiographic volume curve.

This study was designed to more clearly define the relation between various invasive hemodynamic measurements and left ventricular (LV) timing intervals, ejection rate and filling rate derived from the radionuclide angiographic volume curve. Twenty-eight patients were studied with simultaneous intracardiac micromanometer pressure and dP/dt recordings, gated radionuclide angiography and M-mode echocardiography. These techniques permitted multiple variables of systolic and diastolic function to be measured at a constant atrial paced rate of 100 beats/min. There was a strong correlation between peak ejection rate and ejection fraction (r = -0.97) and between peak ejection rate and maximum positive dP/dt (r = -0.85). There also was a strong correlation between peak filling rate and maximum negative dP/dt (r = -0.85). A weaker correlation existed between the time constant of LV relaxation and the peak filling rate (r = -0.49) and between the LV end-diastolic pressure and the peak filling rate (r = -0.62). There was no correlation between the modulus of chamber stiffness and filling rates, and no association was observed between the time to peak filling rate and the hemodynamic variables. Thus, under the conditions studied, the measured peak ejection and filling rate, determined from the radionuclide angiographic volume curve, correlated well with accepted invasive hemodynamic measurements.

Adult↗
PubMed1982

Stress and chronic headache: a psychophysiological analysis of mechanisms.

This study investigated the effects of three types of laboratory stressors (stressful imagery, mental arithmetic, pain) on temporal artery, skeletal muscle, general autonomic [digital blood volume pulse (DBVP), spontaneous resistance responses (SRR's)] and self-report measures of distress in chronic migraine, mixed, muscle contraction and non-headache controls. All subjects were female, free of medication at time of testing and equated for age. Headache subjects reported a 19 year history of headache. Results revealed a pattern of digital BVP (constriction), SSR's (increase) and frontal EMG (increase) indicative of a general autonomic-skeletal muscle arousal response to all three stressors in all groups, while the temporal artery response to the pain stimulus was vasodilation. Distress ratings were elevated during the stress periods for all four group. Pain threshold and tolerance and the tendency to utilize cognitive coping strategies during exposure to pain did not differ across the four groups. The results do not support the general autonomic dysfunction theory of migraine or the specificity hypothesis implicating an overreactive temporal artery or skeletal muscle response to stress in migraine and muscle contraction headache, respectively. Despite epidemiological research supporting the stress-headache relationship, the present results indicate that the psychophysiological mechanism underlying this relationship does not appear to involve abnormal tonic levels or phasic response to stress. It is argued that the temporal artery dilation response to pain questions the role of stress in triggering the two stage vasoconstriction-dilation mechanism of migraine and suggests the need to evaluate a four stage model as a potential psychophysiological mechanism underlying the stress-headache relationship.

Adult↗
PubMed1982

Self-control and chronic headache.

The relationship between self-control and headache pain was studied in a sample of 42 female subjects with migraine or mixed migraine-muscle contraction headaches. Subjects completed questionnaires evaluating self-control tendencies and social desirability. The McGill Pain Questionnaire was also completed during a single representative migraine headache and daily ratings of headache severity (duration, intensity, disability due to pain) and medication intake were collected over a seven-week period. A significant discriminant function which resulted in 71% correct classification of High and Low Self-Control subjects was obtained. The pattern of responses associated with the high self-control group was characterized by lower ratings of pain intensity, less focus on sensory dimensions of pain and more frequent use of certain medications. A correlation between self-control and social desirability was also observed. These findings suggest that the trait self-control may be associated with a particular pattern of pain, although the influence of social desirability cannot be ruled out as an alternative explanation.

Adaptation, Psychological↗
PubMed1980

Antidotes.

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Australia↗
PubMedDate not supplied

Phospholipid metabolites, prognosis and proliferation in human breast carcinoma.

The content of the phospholipid metabolites, phosphocholine, phosphoethanolamine, glycerophosphorylcholine and glycerophosphorylethanolamine was measured in chemical extracts from 46 human breast carcinoma using 31P NMR spectroscopy. Some patients had received therapy prior to tumour resection. The data were therefore stratified into two groups: (i) all tumours; and (ii) untreated tumours. Three indices of tumour proliferation i.e., mitotic index, Ki67 and S-phase fraction were determined on tissue from the same tumours and were found not to correlate with the content of any of these metabolites. In addition oestrogen-receptor status and density, tumour grade and DNA ploidy were obtained on some tumours. The phosphocholine content was higher in high grade tumours when compared with low grade tumours. There was no apparent relationship between DNA ploidy and the content of any of these metabolites. Glycerophosphorylcholine content of oestrogen-receptor positive tumours correlated with receptor density. However, there was no significant difference between receptor positive and negative tumours in the content of any of the phospholipid metabolites measured.

Aneuploidy↗
PubMedDate not supplied

A friend in need...

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Activities of Daily Living↗