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Biomedical subjects

C Spencer

Publications and source records attributed to C Spencer.

At least 73 records · Page 4Linked to original sources
PubMed1988

Measurement and analysis of intraservice work.

The work that physicians perform represents a major resource input to medical services and procedures. In this article we describe the concepts of work and its dimensions, as well as the methods developed to measure them. We also describe the design and results of a national probability survey of physicians in 18 specialties. We present the results--estimated values of work and its dimensions--for selected services. Our findings indicate that physicians can give reliable and valid ratings of work and that we can model this work as a function of four dimensions: time, mental effort and judgment, technical skill and physical effort, and stress. Analyzing the complex functional relationship between work and these four dimensions shows that all four dimensions are important and statistically significant in predicting work. Time is a more important dimension in predicting work for medical specialties than for surgical specialties, with the estimated regression coefficients between .3 and .5 and .2 and .3, respectively. In contrast, technical skill is a more important dimension in predicting work in surgical specialties than for medical specialties, with the estimated regression coefficients between .3 and .5 and .2 and .3, respectively. Finally, we found that an exponential equation of the four dimensions precisely describes total work.

Clinical Competence↗
PubMed1988

The relation of thyroid indices in the critically ill patient to prognosis and nutritional factors.

Thyroid indices and nutritional assessment values were measured in 73 critically ill euthyroid patients within 48 hours of admission to the medical or surgical intensive care unit. Significantly increased rates of mortality were observed among patients with decreased T3 or T4 levels or elevated T3UR or rT3 values. Alterations in thyroid function tests were associated with changes in certain putative nutritional indices, including serum albumin and transferrin concentrations, triceps skin fold and skin test reactivity. The data indicated that thyroid parameters measured early in the critical phase of illness are predictive of subsequent outcome. The pathogenesis of altered thyroid hormone metabolism is unknown, but nutritional deprivation may be an important contributing factor.

Adolescent↗
PubMed1987

Time course and frequency dependence of synaptic vesicle depletion and recovery in electrically stimulated sympathetic ganglia.

The mammalian superior cervical sympathetic ganglion has been extensively used to study the kinetics of ACh metabolism and release. The present investigation examined the time course of changes in the number of synaptic vesicles and abundance of plasma membrane at preganglionic nerve terminals using stimulation protocols similar to those used in previous biochemical and electrophysiological studies. Continuous stimulation of the preganglionic trunk to the cat superior cervical ganglion in vivo produced an initially rapid fall in the number of clear synaptic vesicles followed by a subsequent plateau. Reciprocal changes in plasma membrane occurred with a similar time course. The plateau phase is interpreted as a steady-state where vesicle exocytosis is balanced by the rate of vesicle reformation from plasma membrane. During quiescent recovery, restoration of normal resting ultrastructure is initially rapid but slows with time as vesicle number and plasma membrane abundance approach pre-stimulation values, indicating that the rate of vesicle reformation at the end of stimulation is high and proportional to the number of vesicles incorporated into the plasma membrane. These results are interpreted as consistent with the 'vesicle hypothesis' of neurotransmitter release.

Acetylcholine↗
PubMed1987

Specificity of sensitive assays of thyrotropin (TSH) used to screen for thyroid disease in hospitalized patients.

Thyrotropin (TSH) concentrations were measured in 1580 hospitalized patients and 109 normal persons. Using the mean +/- 3 SD limits of the log values for the controls (0.35-6.7 milli-int. units/L), the proportion of abnormal TSH results in the hospitalized patients was 17.2%. TSH was undetectable (less than 0.1 milli-int. unit/L) in 3.1% of patients, suggesting hyperthyroidism, and high (greater than 20 milli-int. units/L) in 1.6%, suggesting hypothyroidism. On follow-up of 329 patients, 62% with abnormal TSH (less than 0.35 or greater than 6.7 milli-int. units/L) and 38% with normal TSH concentrations, only 24% of those with undetectable TSH had thyroid disease: 36% of them were being treated with glucocorticoids and 40% had nonthyroidal illness (NTI). Although half the patients with TSH greater than 20 milli-int. units/L had thyroid disease, 45% of patients had high TSH values associated with NTI. TSH concentrations usually returned towards normal when patients' therapy with glucocorticoids was discontinued or they recovered from NTI. TSH test sensitivity appeared good when the mean +/- 3 SD limits of the reference population were used, i.e., no cases of hyper- or hypothyroidism, as identified by free thyroxin index (FT4I), were missed. However, TSH test specificity was inferior to that of the FT4I test (90.7% vs 92.3%), although specificity could be improved to 97.0% if the wider TSH reference limits of 0.1 to 20 milli-int. units/L were used--limits considered pathological if applied to outpatients. Evidently, different reference intervals for TSH are needed for hospitalized and nonhospitalized patients. We conclude that a "sensitive TSH assay" is not a cost-effective thyroid screening test for hospitalized patients as compared with the FT4I.

Adult↗
PubMed1985

Treatment of degenerative spondylolisthesis.

The purpose of this article is to evaluate three surgical approaches to the treatment of degenerative spondylolisthesis. A review of 107 surgically treated cases were used to select a group of patients who met the following criteria: No previous spine surgery, no involvement in litigation, and no significant lesions at other levels of the spine. Adequate follow-up. The selected group of 47 surgically treated cases of degenerative spondylolisthesis had follow-up of 2-7 years. Three surgical approaches to the treatment of degenerative spondylolisthesis were analyzed. A relatively small patient group with a wide posterior decompression, at the level of the slip, sacrificing the articular processes had good to excellent results in only 33% of the cases. A second group with a midline posterior decompression with preservation of the articular processes had 80% good to excellent results after 2 years. The third group with a midline decompression and preservation of the articular processes had an added intertransverse process fusion between the olisthetic levels. This group had 90% good to excellent results. The conclusion is that a posterior decompression with preservation of the articular processes plus a transverse process fusion at the involved level is the preferred method of treatment for degenerative spondylolisthesis without regard to age.

Aged↗
PubMed1984

Drug addicts seeking treatment after the Iranian Revolution: a clinic-based study.

A sample survey of 200 addicts attending the Rehabilitation Centre at Shiraz was conducted after the 1979 Iranian Revolution had disrupted both drug supply and addict treatment programmes. The study showed that clinics were, after the revolution, seeing a broader social range of addicts than before; and that action by the authorities was bringing many recently-addicted individuals to clinics. Heroin use predominated among those who were urban residents, whilst villagers were more likely to be opium users. The survey also sought the addicts' perceptions of the reasons for their initiation and addiction.

Adolescent↗
PubMed1983

Exploring the use and non-use of marijuana as reasoned actions: an application of Fishbein and Ajzen's methodology.

Fishbein and Ajzen's methodology can predict behaviour on the basis of questionnaire measures of attitudes toward the specific act and the subjective norms with respect to that behaviour which the individual experiences. In the present study this methodology was used to differentiate between the non-users, experimenters, occasional users and regular users of marijuana in a student population. It is argued that Fishbein's approach enables each of these groups' behaviour to be seen as a reasoned action; also discriminant analysis shows how particular evaluative beliefs and social norms interact to predict and explain the individual's drug-user status.

Adult↗
PubMed1983

Transient effect of L-5-hydroxytryptophan on pituitary function in men and women.

To further elucidate the role of serotonin in the secretion of pituitary hormones, a loading dose of 0.8 mg/kg for 1 h, following by a maintenance dose of 0.1 mg/kg . h of L-5-hydroxytryptophan (5-HTP) for 23 h were administered iv to five normal men and five normal women. Five additional men received repeated loading doses of 5-HTP 4 and 6 h after the initial one, with or without the maintenance dose. The initial studies demonstrated a significant, but transient, increase in plasma PRL, GH, cortisol (P less than 0.01) and TSH (P less than 0.05) in the five man and a consistent and significant transient increase only in PRL and cortisol in the five women. Plasma LH and FSH values were not affected by 5-HTP administration. The constant administration of 5-HTP revealed a blunting effect on the nocturnal rise of TSH in men. The continuous administration of 5 HTP failed to maintain the rise induced by the loading dose. Individuals receiving additional loading doses of 5-HTP demonstrated a subsequent increase in GH and cortisol, but not in serum PRL. This study suggests that endogenous serotonin may exert its stimulatory effect on pituitary hormone secretion primarily by sporadic release, rather than by continuous secretion.

5-Hydroxytryptophan↗
PubMed1982

Observations on the phosphate status and intracellular pH of intact cells, protoplasts and chloroplasts from photosynthetic tissue using phosphorus-31 nuclear magnetic resonance.

Individual pools of intracellular inorganic phosphate (Pi) can be observed in the dark in intact cells, protoplasts and chloroplasts from photosynthetic tissue by using 31P nuclear magnetic resonance (n.m.r.). Estimates for the pH of vacuolar and extravacuolar compartments are reported although it is shown that intracellular pH is determined by the pH of the suspending medium. Mannose treatment of asparagus (Asparagus officinalis) cells and spinach (Spinacia oleracea) protoplasts results in the inhibition of photosynthesis. The mechanism of mannose phosphate sequestration of free Pi is supported by the 31P n.m.r. spectra of mannose-treated tissue. There is a fundamental difference in 31 P n.m.r. spectra of mannose-treated spinach protoplasts and asparagus cells, reflecting a difference in the availability of vacuolar Pi for cellular metabolism in these species. The 31P n.m.r. spectrum of intact spinach chloroplasts is reported.

Chloroplasts↗
PubMed1982

Patterns of drug use among secondary school children in post-revolutionary Iran.

A sample survey of 712 Iranian youths aged 14 - 18 years, attending secondary schools in the city of Isfahan, indicated that 11% had had experience of drug abuse. The most common pattern was the experimental use of opium, with a minority of users having also used hashish or heroin. No other drugs were reported, but a significant association between the use of opium and of cigarettes and, to a lesser extent, alcohol was observed. However, given a relatively early peak in initiation to opium smoking, it seems that the initiation to the use of cigarettes and alcohol is contemporary with, rather than preceding the initiation to opium. Drug migration patterns described in Western samples and in some areas of South East Asia are not applicable to more traditional societies.

Adolescent↗
PubMed1982

Social background, personal relationships, and self-descriptions as predictors of drug-user status: a study of adolescents in post-revolutionary Iran.

Iranian adolescents who have ever used drugs exhibit significant differences from their non-using peers in terms of their lowered educational aspirations, reported health and sense of well-being; and they would be more likely to rely upon friends' rather than parents' support if in serious trouble. But, unlike many studies of European, American and South-East Asian adolescents, the present sample of drug users show few other signs of rebelliousness or alienation: they report themselves as religious as the non-users, and their school performance is little depressed. The drug user sub-sample contains a disproportionately high number of children from both the richest and the poorest families in society.

Adolescent↗
PubMed1982

Cardiovascular effects of phenelzine and amitriptyline in depressed outpatients.

Blood pressure and ECG changes were monitored in depressed outpatients treated for 6 weeks with amitriptyline, 150 mg/day, or phenelzine, 60 mg/day, as part of an ongoing double-blind study. Phenelzine produced significant decreases in blood pressure and a significant increase in orthostatic fall in pressure. Amitriptyline produced little overall change in blood pressure. The degree of MAO inhibition in phenelzine-treated patients was significantly correlated with blood pressure. Tricyclic plasma concentrations were also related to some blood pressure measures. Reported dizziness/faintness did not correlate with blood pressure changes in either group. Amitriptyline significantly increased heart rate, while phenelzine produced slowing. Amitriptyline was associated with significant prolongation of QRS and QTc but not PR intervals. Phenelzine produced significant shortening of the QTc interval.

Adult↗
PubMed1981

Critical appraisal of complement dependent microlymphocytotoxicity assay for detecting donor-specific alloantibody pretransplant--importance of indirect immunofluorescence as a superior alternative.

The ability of complement-dependent microlymphocytotoxicity assay (CdL) to detect and discriminate between the various types of donor-specific alloantibodies was reevaluated. Data obtained with the CdL assay on purified B and T lymphocytes at warm and cold temperatures was compared to other modes of antibody-detection, i.e., indirect immunofluorescence (IF) and the noncomplement-dependent antibody-dependent cellular cytotoxicity (ADCC). Additionally, the significance of antibodies as detected by CdL and IF was ascertained by correlating with kidney transplant outcome. It became apparent that the CdL assay identified weakly reactive HLA-ABC alloantibodies as being B cell specific. Such weakly reactive HLA-ABC antibodies were also not appreciated in the presence of the cold reactive IgM antibody. Accelerated rejections were the rule in the presence of weakly reactive HLA-ABC alloantibodies indicating that their detection was highly important. The IF assay could discriminate between the antibody class, could detect weakly reactive HLA-ABC alloantibodies, and could detect noncomplement fixing antibodies (ADCC). Further, use of IF prevented us from unnecessarily denying transplants to certain recipients when a positive CdL assay resulted from an IgM antibody or poor cell viability.

Antibody Specificity↗
PubMed1980

Social background and attitudes towards drugs as predictors of drug use among Malaysian students.

Those Malaysian secondary schoolchildren who have ever used an illicit drug do not differ significantly in terms of social class background, ethnicity or rural/urban location, from the majority of their contemporaries who have not used drugs. The cross-sectional data show a rapid secular trend towards the sexes being equally involved in drug use. Significant differences between ever and never users are, however, found in their attitudes towards drug taking and their beliefs about the properties of drugs, although both groups share the same rather negative image of the typical drug user. Thus, drug users have accepted some of the attitudes towards drug issues which are normative in the non-user group, whilst developing other attitudes which are consistent with their continuing use. It is argued that adolescent drug abuse in Malaysia is not to be linked specifically with social deprivation, but should be seen as being part of the life style of particular groups in all strata of society.

Adolescent↗
PubMed1980

Social attitudes, self-description and perceived reasons for using drugs: a survey of the secondary school population in Malaysia.

The present paper is the third and concluding part of a study of the secondary school population of two of Malaysia's thirteen states, Penang and Selangor. Since completion of the two earlier papers, the research team has investigated the pattern and nature of drug use among the equivalent population in a third state, Kelantan, and has again found essentially the same pattern of results: youthful drug use is most clearly related to precocious self-assertion, and a set of beliefs and attitudes about drugs and drug taking, and is largely unrelated to indicators of social deprivation or personal problems. The significance of this repeated finding in Kelantan is that, in this much more rural and traditional state, adult and established patterns of drug use had historically differed considerably from those found in the two more urban and cosmopolitan states of Penang and Selangor. Our findings indicate that the new pattern of drug use by youth has transcended the older cultural differences between the states, and is in turn explained by a more universally familiar set of characteristics in adolescent development.

Achievement↗
PubMed1980

Patterns of drug use amongst Malaysian secondary schoolchildren.

A representative sampling of the secondary school population of two states of Malaysia (sample size 16166) indicated that 11% of students had had experience of drug use. Use of a single drug was the common pattern, with cannabis reported most often by older students, and sedatives most often by younger students. A quarter of those who had used drugs reported experience with four or more substances and were likely to have progressed rapidly to heroin. This progression may be facilitated by the ready availability of heroin and the local tradition of smoking or inhaling rather than injecting opiates. Descriptions of drug migration patterns based on Western samples are not fully appropriate worldwide, because the youthful abuser is much influenced both by local market forces and by cultural traditions, even though the epidemic of youthful drug abuse is itself worldwide.

Adolescent↗
PubMed1980

Legal sanctions and information about drugs as influences upon the decision by adolescents whether to use illicit drugs.

Although those Malaysian secondary schoolchildren who have never used drugs are consistent in their support for legal and social sanctions against drug use, it is argued that such sanctions are a relatively unimportant factor in the decision whether or not to use drugs. Non-drug users inhabit a social world separated from their drug-using contemporaries; they rely on information from public rather than direct social sources, and claim to have been little interested in information received. However, there is evidence that, for a minority of the drug-using sub-sample, public information campaigns have made them more rather than less interested in experimenting with drug substances.

Adolescent↗