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Biomedical subjects

T Cox

Publications and source records attributed to T Cox.

At least 91 records · Page 5Linked to original sources
PubMed1989

Identification of calcium conducting channels in isolated boar sperm plasma membranes.

Ion channel recordings were obtained from liposomes containing purified boar sperm plasma membrane proteins using a tip-dip method. Liposomes prepared in HEPES-TRIS and clamped by electrodes containing Ba-HEPES displayed channel activity that was partially inhibited by verapamil or nitrendipine and completely inhibited by La3+. Reversal of current at pipette negative voltages was observed only when Ba2+ ions were also present in the bath solution. These data indicate that channels capable of carrying calcium currents are prominent components of the plasma membrane of mammalian sperm.

Animals↗
PubMed1989

Do subjects with stiff arteries have high blood pressure?

It has been argued that age-related increases in arterial stiffness could lead to spuriously high indirect blood pressure measurements, with consequent overdiagnosis of hypertension in older patients. To study the relationship between arterial stiffness and blood pressure, we identified patients with 'arterial stiffness', using Osler's manoeuvre, and compared their blood pressure levels with patients of a similar age. A total of 250 hospital inpatients were assessed independently by two doctors. In the 198 patients (79%) where both observers agreed on Osler's manoeuvre status, positive Osler's manoeuvre was uncommon under the age of 50 years but became more common thereafter, rising to 58% of patients aged over 75 years. However, blood pressure levels were similar in each age group, irrespective of Osler's manoeuvre status. We conclude that increased arterial stiffness as measured by Osler's manoeuvre is not necessarily associated with raised blood pressure levels in the elderly.

Adolescent↗
PubMed1988

Separation of synthetic cycloalkylated bases, nucleosides and nucleotides by reversed-phase high-performance liquid chromatography.

Reversed-phase high-performance liquid chromatography was used to determine the elution profiles of a series of synthetic cycloalkylated bases, nucleosides, and their corresponding 5'-monophosphates. A 70% aqueous methanol solution proved to be the most efficient solvent system for the separation of a mixture of the bases, all of which were eluted in times ranging from 3.3 to 4.8 min at a flow-rate of 0.8 ml/min. Subsequently, the same percentage of methanol solvent, at 0.8 ml/min, eluted the nucleoside mixture as well, with retention times ranging from 3.3 to 5.0 min. Optimum separation and resolution were achieved with 70% methanol at a flow-rate of 0.6 ml/min for a mixture of the base and nucleoside series. A phosphate buffer, containing acetonitrile-tetrabutylammonium ion, was used to analyze the 5'-monophosphate derivatives. Elution times ranged from 2.6 to 6.1 min at a flow-rate of 1.0 ml/min. Three variables were considered in order to determine optimum conditions for separation and resolution: (a) the percentage of methanol in the solvent; (b) flow-rate of solvent; and (c) the size of the cycloalkylated group of each synthetic analogue. The procedures and conditions described herein have potential use as a monitoring system to detect modified nucleic acid derivative which are prevalent in the body fluids of patients with certain metabolic disorders.

Alkylation↗
PubMed1988

Effects of telic dominance and metamotivational state on squash task performance.

Measures of telic dominance and metamotivational state were obtained from 40 volunteer males grouped on the basis of their playing ability, before and after the performance of squash tasks. Utilising a mixed-blocks design, which controlled for order of task, subjects were required to perform two squash tasks of differing difficulty. Significant differences between groups on performance were obtained, confirming the ability classification, but no significant differences in telic dominance were found. Significant increases in mood response in the telic direction were found on pre- and posttask scores. A significant decrease in discrepancy scores (preferred arousal minus felt arousal) obtained pre- and posttask was noted, together with a significant interaction between skill level and in arousal discrepancy pre- and posttask. In all cases trends were least for the most skilled group.

Adolescent↗
PubMed1987

Factor II, VII, IX and X concentrations in patients receiving long term warfarin.

Using standard one stage clotting assays the concentrations of factors II, VII, IX and X were determined in 37 patients stabilised on warfarin for between three months and 17 years. Contrary to popular belief, the concentrations were not equally depressed, with factor X the lowest, factor II at intermediate value, factors VII and IX the highest. Some 71% of the variance of the British corrected ratio (BCR) could be accounted for by measurement of the factors assayed. Analysis of this variance showed 91% of the explained variance attributable to factor II, 7% to factor VII, 1.6% to factor IX and 0.4% to factor X. With the sudden and recent withdrawal of human thromboplastin, investigation of the sensitivities of the animal thromboplastins to changes in vitamin K dependent factors in orally anticoagulated patients is needed to ensure that the potentially alarming falls in factors II and X in these patients are being adequately detected.

Adult↗
PubMed1987

Neurohumoral mechanisms and left ventricular hypertrophy: effects of hygienic therapy.

To determine the effects of hygienic (non-drug) therapy on blood pressure (BP) control and its relationship to sympathetic tone and left ventricular mass (LVM) in primary hypertension, plasma norepinephrine (NE) and renin activity (PRA), LVM, and nutritional and behavioral status were assessed in 76 borderline to mild hypertensives. Pretherapy plasma NE was related to diastolic blood pressure (DBP) and PRA (r = 0.24, P less than .05 and r = 0.37, P less than .01, respectively). Plasma NE of high renin patients (221 +/- 52) (mean +/- SD) was greater than that of normal renin patients (159 +/- 61, ng/l, P less than .01). LVM was related to systolic blood pressure (SBP) (P less than .001), DBP (P less than .01) and urinary sodium (P less than .05), and inversely related to PRA (P less than .01). Septal wall thickness was related to hostility (r = 0.42, P less than .05). After seven weeks of hygienic therapy, DBP was reduced by 6 mmHg (P less than .01). The change in SBP was related to baseline plasma NE (P less than .05) and inversely related to LVM (P less than .05). These results suggest that raised sympathetic tone may be a pathogenic factor in primary hypertension and that hygienic therapy lowers BP more effectively in patients with raised sympathetic tone and low LVM.

Adult↗
PubMed1986

Psychological and physiological reactions to visual representations of war.

This paper explores the immediate psychological and physiological effects of aversive visual stimuli, represented as pictures of war, in a balanced mixed design (n = 24). The moderating effects of individual differences in locus of control and sex were examined, along with those of a requirement to report on the stimuli presented. The results indicated a fractionation of the autonomic response with electrodermal measures (EDA) and salivary function showing a sympathetic type response to war slides whilst measures of cardiac activity (heart rate and heart rate variability) tended to show increased parasympathetic activity over the response to neutral slides. Psychological measures showed an increase in self-reported stress, higher disturbance ratings and unprompted reports of various coping strategies (postexperimental interviews) in response to war slides. Additionally, self reported arousal and EDA's proved sensitive to the report requirement and cardiac activity appeared to be tied to individual differences in terms of locus of control. Although the physiological results could be taken as congruent with Hare's (1972) suggestion that 'morbid curiosity' accompanies the viewing of aversive stimuli, psychological measures tended to disconfirm this interpretation. The situational determinants of the cardiac response are discussed as a solution to the paradoxical cardiac response elicited with aversive visual stimuli, along with individual styles of coping with aversive situations which may be reflected in individual's locus of control.

Adolescent↗
PubMed1986

Smoking behaviour under conditions of relaxation: a comparison between types of smokers.

Smoking behaviour, self-reported mood and cardiac activity were examined in 12 "sedative" and 12 "stimulant" smokers, defined using Mangan and Golding's questionnaire. This concerns the interaction between urge to smoke and external situation. "Sedative" smokers appear to experience their greatest need to smoke in situations characterized by low arousal; "stimulant" smokers in situations of high arousal. Members of each group were examined in two low arousal conditions. In one condition smoking was allowed, and in the other it was not. When allowed to smoke, it was shown that the two groups differed in their smoking behaviour: 10 stimulant but only 2 sedative smokers chose to do so. However, although smoking caused a significant increase in cardiac activity in smokers, no effects on subjective arousal were found. The implications of these findings are discussed.

Adult↗
PubMed1986

Recurrent sterile meningitis caused by a pituitary abscess.

The case of a 21 year old woman who presented with recurrent sterile meningitis and bitemporal hemianopia is described. Computed tomographic scan showed a large low density ring enhancing lesion above and within the pituitary fossa which at operation and on histological examination was found to be compatible with an abscess. The visual field defect recovered completely and the scan appearances returned to normal postoperatively.

Abscess↗
PubMed1985

The measurement of self-reported stress and arousal.

This paper provides further discussion on the measurement of mood using self-report inventories. It comments on questions raised by Cruickshank (1984) about the structure and use of the stress-arousal checklist developed by Mackay and Cox (Mackay et al., 1978).

Affect↗
PubMed1984

Converging and diverging beliefs about arthritis: Caucasian patients, Spanish speaking patients, and physicians.

Ninety-eight Caucasian patients, 46 Spanish speaking patients, and 50 physicians (mainly rheumatologists) took part in surveys of salient beliefs about arthritis and its treatment. The beliefs of Caucasian patients and those of physicians were similar. However, beliefs of physicians about patients' beliefs and actual patient beliefs diverged as did the beliefs of Caucasian and Spanish speaking patients. These results suggest that arthritis education and treatment should be based on patients' perceptions rather than on physicians' beliefs about patients' perceptions.

Adult↗
PubMed1983

The nature and assessment of general well-being.

Data on self-reported symptoms of ill-health were collected from 1500 respondents, and factor analysed. The results of this analysis suggested a two factor orthogonal model of well-being: one factor reflecting fatigue, emotional fragility and confusion (worn-out) and the other tension, anxiety and agitation (up-tight). The reliability and validity of the model were tested and appeared acceptable, and scales were constructed for the assessment of the two factors. It is suggested that the model and the associated scales could offer new information in studies of occupational stress and health.

Data Collection↗