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Biomedical subjects

N Biddle

Publications and source records attributed to N Biddle.

10 recordsLinked to original sources
PubMed1991

Obtaining outpatient referrals for clinical research.

Two methods of recruiting patients with generalised anxiety disorder (GAD) were compared. One hundred general practitioners in the immediate neighbourhood of a major urban hospital were approached for referrals, and an article on generalised anxiety asking for volunteers was placed in the evening newspaper. The former resulted in ten doctor-initiated referrals, two of whom fulfilled DSM-III criteria for GAD. The latter resulted in over 500 volunteers. In a random selection of 136 volunteers who secured their doctors' approval, 56 fulfilled GAD criteria. The majority of the remainder had a depressive illness. The newspaper article was more economical of researchers' time and more successful in finding suitable subjects than directly approaching general practitioners.

Adult↗
PubMed1990

Reactions of first-year medical students to their initial encounter with a cadaver in the dissecting room.

This study reports the results of a 1986 questionnaire survey of 100 first-year medical students regarding their preparation for and reactions to their first encounter with a human cadaver in the dissecting room. The students were aware of psychological and physical reactions to this experience, and although they felt adequately prepared prior to the class, expressed a desire for greater preparation afterwards, particularly through more discussion of the experience with the anatomy staff. A surprising number of the students (62) had had prior exposure to a dead human body, which was a significant influence upon their reactions. The results of this study suggest a need for improving both the preparation for coping with dissection and the follow-up opportunities for dealing with professional and emotional issues raised during human dissection.

Adaptation, Psychological↗
PubMed1990

Psychiatry as a career choice.

The paper reviews articles in the field of research in medical education specifically dealing with the factors involved in the choice of Psychiatry as a medical specialty and describes three studies conducted in Melbourne. These studies focus on the relevance of personality factors in the psychiatrist's choice of a career. While they confirm other work in this field, it is felt that the emphasis should no longer be placed on single factors. Future investigations should be multifactorial in design and analysis to highlight the combination of factors underlying such choices.

Adult↗
PubMed1988

The dexamethasone suppression test and plasma dexamethasone in generalized anxiety disorder.

A Dexamethasone Suppression Test nonsuppression rate of 27% was found in a group of 30 generalized anxiety disorder patients before treatment. The dexamethasone concentrations in the eight nonsuppressors were significantly lower than in eight suppressors matched by sex and age, but were similar to those in five nonsuppressors from a matched normal control group. The dexamethasone concentrations in the generalized anxiety disorder suppressors and a matched group of eight normal control suppressors were similar. After successful nondrug behavioral treatment, all generalized anxiety disorder patients were suppressors. Posttreatment dexamethasone concentrations in the initial nonsuppressor patients remained significantly lower than in the initial suppressors. The results suggest that low plasma dexamethasone concentrations after 1 mg oral dexamethasone may confer a vulnerability to nonsuppression that may be expressed in the presence of high state anxiety.

Adult↗
PubMed1988

The dexamethasone suppression test: a study in a normal population.

One hundred healthy, non-depressed volunteers were given a standard dexamethasone suppression test (DST) to determine the appropriate criterion values of plasma cortisol to define suppression or nonsuppression. By radioimmunoassay (RIA) of cortisol, the criterion value for 5% nonsuppression was plasma cortisol greater than 187 nmol/l, and for suppression less than 153 nmol/l, with an indeterminate range between these values. Use of the widely accepted pre-determined criterion value of 138 nmol/l gave a significantly greater frequency of nonsuppression. Values of cortisol measured by two RIAs in a subset of 43 volunteers were not equivalent. With the experimentally determined criterion value, no significant differences between nonsuppressors and suppressors were found for any measured physical or psychological parameters. Women taking oral contraceptives had significantly higher plasma cortisol pre-dexamethasone and post-dexamethasone. Their exclusion did not alter the calculated criterion value for the remainder, but their separately estimated criterion value was significantly higher. Caution should be exercised when classifying the DST status of women on oral contraceptives, particularly when values are at the lower end of the nonsuppressor range. Determination of a separate normal range for them may be warranted.

Adrenocorticotropic Hormone↗
PubMed1987

The dexamethasone suppression test: importance of dexamethasone concentrations.

Plasma dexamethasone concentrations and cortisol response to dexamethasone were measured in 29 normal healthy volunteers, 23 depressed patients, and 10 patients with anorexia nervosa at 4:00 PM postdexamethasone. In each of the 3 groups, nonsuppressors had lower dexamethasone concentrations than suppressors. Of the subjects with plasma dexamethasone at or below 0.7 ng/ml, a significantly higher proportion (48%) were nonsuppressors compared to the proportion above 0.7 ng/ml (14%), all of whom were patients. Plasma dexamethasone concentrations in a subgroup of depressed nonsuppressors were high (mean 1.35 ng/ml), whereas the remainder were low (0.42 ng/ml) and were similar to the normal nonsuppressors (0.35 ng/ml), suggesting different mechanisms for nonsuppression in the subgroups. Plasma dexamethasone concentrations were similar in nonendogenous and endogenous depressives, in men and women, and in medicated and drug-free patients. None of the variables of age, weight, history of weight loss, Hamilton depression rating score, predexamethasone cortisol, or postdexamethasone cortisol were significantly correlated with plasma dexamethasone, except for body weight and a history of weight loss in the depressed group only. Mean plasma dexamethasone concentrations increased significantly from week 1 to week 2 in 7 depressed patients, whereas plasma cortisol decreased; however, the relationship between dexamethasone and cortisol varied considerably for individual patients.

Adolescent↗
PubMed1987

Prediction of outcome in depressed patients by weekly monitoring with the dexamethasone suppression test.

Forty-three depressed patients in hospital were studied with weekly dexamethasone suppression tests (DSTs) and were followed as out-patients for at least three months after discharge. The detection rate of patients with LHPA axis dysfunction increased from 41% with a single DST to 59% with serial DSTs. There was a poor correlation between weekly post-dexamethasone cortisol levels and Hamilton depression rating scores. In patients with evidence of LHPA axis dysfunction, a DST at discharge discriminated effectively between a good and a poor outcome group; persistent non-suppression was strongly linked with a relapse of depression in the first three months after discharge. In general, our results support previous claims that the DST is a state marker for depressive illness.

Depressive Disorder↗
PubMed1987

Anxiety disorder and perception of inspiratory resistive loads.

Sensations of breathlessness in the absence of respiratory disease are common in anxiety disorders. Perceptions of breathlessness in eight patients with anxiety disorder were compared with eight normal control subjects, matched for age and sex, by the application of Steven's law to the magnitude of resistive load test. All subjects estimated the magnitudes of resistive loads to inspiration while peak inspiratory mouth pressures were monitored. Anxious patients' perceptions of the added loads were significantly less sensitive than normal, even though the effort, determined by peak inspiratory mouth pressure, in overcoming each load was normal. Correlations between estimates of resistive loads and peak inspiratory mouth pressure were significantly less for the anxious patients than for normal subjects. Thus, perception of breathlessness in anxiety disorders may be affected by factors not normally associated with breathlessness and may help account for the greater than normal variability in resistive load perception in respiratory disease.

Airway Resistance↗
PubMedDate not supplied

Panic disorder, the ventilatory response to carbon dioxide and respiratory variables.

Increased sensitivity of the central carbon dioxide chemoreceptors to carbon dioxide has been hypothesized as a biologic determinant of panic attacks in panic disorder and on voluntary inhalation of carbon dioxide mixtures. The ventilatory response to carbon dioxide, a measure of sensitivity, was assessed in 12 patients with panic disorder and 12 matched normal controls. While mean sensitivity was similar for both groups, for the panic disorder patients, mean sensitivity due to the tidal volume component was significantly less than for the normal controls, and mean sensitivity due to the frequency component was significantly greater than for the normal controls. The interpretation of the effects of carbon dioxide inhalation as a neurobiologic and behavioral probe may be enhanced if the components of the ventilatory response are examined separately.

Adult↗