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Biomedical subjects

P Joyce

Publications and source records attributed to P Joyce.

At least 37 records · Page 2Linked to original sources
PubMed1996

Plasma cortisol, PRL, ACTH, AVP and corticotrophin releasing hormone responses to direct current cardioversion and electroconvulsive therapy.

OBJECTIVE: We aimed to evaluate and contrast the hypothalamo-pituitary-adrenal (HPA) response to direct current (DC) cardioversion and electroconvulsive therapy (ECT). SUBJECTS: Six male subjects (mean age 61.2 years, range 46-74) with chronic atrial fibrillation were selected for cardioversion. Six subjects with depression (one male, five female; mean age 43.2 years, range 31-59) were selected for ECT. Those taking glucocorticoid drugs, opiates or beta-adrenoceptor antagonists were excluded. MEASUREMENTS: Patients attended for serial blood sampling on the day of cardioversion or ECT, and for an equivalent time period on a control day at least one week before. Intravenous propofol was given to each subject for anaesthesia on the day of cardioversion or ECT. On both study and control days, blood samples were taken at -30, -15, 0 (just prior to cardioversion or ECT), +5, +10, +15, +30, +60, +90 and +120 minutes for assay of cortisol, PRL, ACTH, AVP and CRH. RESULTS: For cardioversion: plasma cortisol increased from 252.5 +/- 39.8 to a maximum of 721.3 +/- 50 nmol/l at 30 minutes (P < 0.0001 compared with control day). ACTH increased from 12.8 +/- 2.8 to a maximum of 64 +/- 14 pmol/l at 5 minutes (P < 0.0001 compared with control day). AVP increased from 6.6 +/- 3.3 to a maximum of 42.9 +/- 16 pmol/l at 5 minutes post-cardioversion (P < 0.005 compared with control day). PRL increased from 141 +/- 28 mlU/l to a maximum of 873 +/- 219 mlU/l at 10 minutes (P < 0.001 compared with control day). There was no significant difference in CRH responses between cardioversion and control days. There was no significant correlation between total electrical energy delivered and maximum ACTH and AVP responses (R = 0.54 and -0.13, respectively). For ECT: on the day of ECT plasma cortisol increased from 419.5 +/- 25.9 to a maximum of 614.7 +/- 26.9 nmol/l (P < 0.002 compared with control day). ACTH increased from 22.7 +/- 6.2 to a maximum of 77.8 +/- 19.1 pmol/l (P < 0.0003 compared with control day). PRL increased from 771 +/- 317 to a maximum of 3152 +/- 703 mlU/l (P < 0.001 compared with control day, and significantly greater than the peak response to cardioversion, P < 0.03). AVP increased from 13.0 +/- 10.8 to a maximum of 35.1 +/- 5.6 pmol/l (P < 0.02 compared with control day). There was no significant difference in CRH responses between ECT and control days. Peak cortisol and ACTH responses did not differ significantly between ECT and cardioversion. Baseline cortisol levels, however, were significantly higher in the depressed group compared with the cardioversion group, P < 0.02, but not ACTH or AVP. CONCLUSION: Significant hypothalamic-pituitary-adrenal activation and PRL release occur in response to both cardioversion and ECT. AVP may have an important role in mediating the acute ACTH response to electrical stimulation.

Adrenocorticotropic Hormone↗
PubMed1995

The distribution of rare alleles.

Population geneticists have long been interested in the behavior of rare variants. The definition of a rare variant has been the subject of some debate, centered mainly on whether alleles with small relative frequency should be considered rare, or whether alleles with small numbers should be. We study the behavior of the counts of rare alleles in samples taken from a population genetics model that allows for selection and infinitely-many-alleles mutation structure. We show that in large samples the counts of rare alleles--those represented once, twice, ...--are approximately distributed as a Poisson process, with a parameter that depends on the total mutation rate, but not on the selection parameters. This result is applied to the problem of estimating the fraction of neutral mutations.

Alleles↗
PubMed1995

Silicosis and workers' compensation in New Jersey.

The employer is expected to maintain responsibility for health care expenses and lost income that result from occupational injury and illness through the workers' compensation insurance system. However, financial support for individuals with occupational illnesses, especially those with long latency, is often from sources other than workers' compensation. Silicosis, a well defined, chronic, occupational lung disease, can be viewed as a sentinel for the inadequacy of the public policy to compensate workers for chronic occupational lung disease. Three hundred twenty-nine patients with confirmed silicosis were identified by the silicosis surveillance program in the New Jersey Department of Health using source data from 1979 through 1992. One hundred seventy-seven of these individuals provided information on the status of any compensation claims against their employer. Only 31% of these patients stated that a claim had been filed; 84% of those whose claims were settled were awarded payments. Severity of radiologic findings was not associated with the likelihood of filing a claim or with being awarded a payment; whereas, smoking was associated with these outcomes. The implications of these findings for the health care system are discussed.

Aged↗
PubMed1993

Type I hypersensitivity reactions in intestinal mucosae from rats infected with Fasciola hepatica.

Type I hypersensitivity reactions in the intestinal tract of sensitized animals may contribute to resistance to reinfection with Fasciola hepatica. Colonic mucosae isolated from previously infected rats were voltage clamped in Ussing chambers. Antigen was prepared as a crude homogenate from adult liver fluke. Assay of serum antibodies against fluke antigen confirmed sensitization. Antigen challenge evoked a rapid onset, transient inward current in sensitized but not in control preparations. Chloride secretion accounted for at least part of the response since the loop diuretic bumetanide reduced the effect of antigen by 61%. Anti-rat IgE mimicked the response to antigen and desensitized tissues to subsequent antigen challenge. Local synthesis of eicosanoids may mediate the response to antigen since the cyclo-oxygenase inhibitor piroxicam reduced the response by 76%. In contrast, mepyramine which is a histamine receptor antagonist did not alter the ion transport response evoked by antigen. Tetrodotoxin reduced the response to antigen by 53% implicating intrinsic neurons within the lamina propria as effector cells in the responses of this tissue to antigen. We propose that antigen stimulation of electrogenic chloride movement and consequent fluid secretion in vivo may contribute to a local effector mechanism in prevention of reinfection of previously sensitized hosts.

Acetylcholine↗
PubMed1992

Leiomyosarcoma of the femoral vein.

Soft-tissue masses uncommonly completely occlude or engulf a major vessel. Complete occlusion of a major vein suggests that the mass originates in the wall of the vein. Such tumours are rare, the most frequently encountered type being leiomyosarcoma. The authors present a case of leiomyosarcoma of the femoral vein.

Aged↗
PubMed1991

Identification of phosphorylcholine containing antigens of Fasciola hepatica--successful tolerization against this epitope in experimental animals.

Phosphorylcholine containing antigens have been identified in the parasite Fasciola hepatica by immunoblotting and ELISA. Immunoblots probed with polyclonal and monoclonal antibodies indicate that the majority of antigens identified in both the immature and mature parasite contain both phosphorylcholine and non-phosphorylcholine epitopes. One antigen of 58 kDa appears to contain predominantly PC epitopes or at least this epitope is the major one responded to by host animals. Successful immunotolerization against the epitope PC was achieved by injecting the PC conjugate, ovalbumin PC, into neonatal rats. Immunotolerization against PC resulted in a 25% reduction in worm burden upon subsequent infection with Fasciola hepatica.

Animals↗
PubMed1990

Prevalence of three bulimia syndromes in the general population.

Prevalence of bulimia was estimated from a cross-sectional general population survey of 1498 adults, using the Diagnostic Interview Schedule (DIS) administered by trained lay interviewers. Lifetime prevalence of the DSM-III syndrome in adults aged 18-64 was 1.0% and this was concentrated in young women: in women aged 18-44 lifetime prevalence was 2.6%, and 1.0% currently had the disorder. Based on clinicians' reinterviews of random respondents and identified and marginal cases, the prevalence of current disorder using criteria for draft DSM-III-R bulimia was 0.5%, for DSM-III it was 0.2%, and for Russell's Criteria bulimia nervosa 0.0%. A strong cohort effect was found, with higher lifetime prevalence among younger women, which is consistent with a growing incidence of the disorder among young women in recent years. Although elements of the syndromes were so common as to suggest that dysfunctional attitudes to eating and disturbed behaviour surrounding eating are widespread, there was little evidence of the bulimia syndrome having become an epidemic on the scale suggested by early reports.

Adolescent↗
PubMed1989

Is knowing the age-order of alleles in a sample useful in testing for selective neutrality?

The most powerful, and most frequently used, test of selective neutrality, based on data consisting of observed allelic frequencies in a sample of genes at some locus, is the procedure of G. A. Watterson. This procedure uses the sample homozygosity F* as the test statistic, and in effect leads to rejection of the hypothesis of selective neutrality if the observed value of F* differs significantly from neutral theory expectations. The homozygosity statistic is invariant under relabeling of the alleles and thus cannot use any further information on the alleles which might be available. We present results which suggest that information concerning the age order of the alleles cannot be used to provide a more powerful testing procedure than that of Watterson.

Alleles↗
PubMed1988

Psychotic disorders.

Explore the source record for details and available documents.

Community Mental Health Services↗
PubMed1980

Benzodiazepine withdrawal syndromes.

We report eight cases of benzodiazepine withdrawal syndromes seen in a general psychiatric hospital. These consisted of acute organic brain syndrome, grand mal convulsions and abstinence syndromes. All of the cases were using benzodiazepines in prescribed therapeutic doses. These problems appear to be more common than are generally acknowledged.

Adult↗
PubMed1980

Varied appearance of trigeminal neuroma on CT.

The computed tomographic (CT) scans of five patients with surgically and histologically proven trigeminal neuromas demonstrated the varied appearance of this tumor. In this series, tumors appeared in the middle cranial fossa, the posterior cranial fossa, or extended into both. Prior to contrast infusion, the tumors showed low density, normal brain density, or mixed normal and low density on the CT Scan. After contrast infusion, all tumors were well circumscribed with marked enhancement, which was either homogeneous or inhomogeneous. None of the trigeminal neuromas had surrounding brain edema. The three larger tumors had significant mass effect with hydrocephalus and displacement of the fourth ventricle or compression of adjacent cisterns.

Adult↗
PubMed1979

Continuous variability of fetal PO2 in the chronically catheterized fetal sheep.

A method of continuous monitoring of fetal intravascular PO2 at various sites in the circulation in the chronically catheterized fetal sheep for up to 41 days (mean 11.1 days) has been compared with values obtained in blood samples measured extracorporeally in a standard blood gas analyzer. A double-blind comparison of the two methods showed that there was no bias between the two methods and correlation was 0.94. The stability of the electrodes was superior to that of a conventional blood gas analyzer. In every animal there was continuous variability of fetal vascular PO2. In the period from 105 to 126 days' gestation we noted the presence of slow increases in basal uterine tone that we have called "contractures". The frequency of these contractures was very regular at approximately one per hour. The frequency of these contracutres was very regular at approximately one per hour. There is a statistically significant related fall in fetal vascular PO2 in relation to these contractures. Well-coordinated uterine contractions during labor also produced a fall in fetal vascular PO2 that was related to the uterine activity.

Animals↗