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Biomedical subjects

A Swann

Publications and source records attributed to A Swann.

At least 55 records · Page 3Linked to original sources
PubMed1996

Dose response characteristics of methylphenidate on different indices of rats' locomotor activity at the beginning of the dark cycle.

Using a computerized infrared activity analysis system, the dose-response relationship, timing, and duration for stimulation of motor activity after a single dose of methylphenidate was studied in Sprague-Dawley rats. After 5 days of acclimation and 2 days of monitored baseline activity, rats received a single subcutaneous injection of vehicle or of 0.6, 2.5, 10 or 40 mg/kg methylphenidate 1 h into the dark cycle. Recording was then resumed for an additional 36 h. Five locomotor indices were analyzed. Each locomotor parameter monitored different aspects of motor activity. The doses of 2.5, 10 and 40 mg/kg significantly increased (P < 0.01) locomotor activity. The time to maximal effect (20, 50, and 90 min) and duration of effect (70, 210, and 280 min) increased with dose respectively. Ten mg/kg had the maximum effect on locomotor activity, while the largest dose, 40 mg/kg, elicited a more focused stereotyped activity that limited the amount of forward ambulation. Single injections of methylphenidate did not alter motor activity the next day. Pharmacological parameters and specific locomotor parameters describing the effects of methylphenidate at the beginning of the dark cycle can later be used in chronopharmacologic studies. They will also provide the basis for investigation of adaptive mechanisms during repeated or chronic administration of methylphenidate.

Analysis of Variance↗
PubMed1996

Preliminary physiologically based pharmacokinetic model for cocaine in the rat: model development and scale-up to humans.

A physiologically based multicompartmental model has been developed to describe the concentration-time course of cocaine in plasma and tissues in the rat. The compartments included in the model were brain, heart, gut, liver, muscle, fat, venous blood, arterial blood, and a mass-balance compartment. Drug delivery to the tissues was assumed to be flow limited. The model incorporated a nonsaturable binding site for cocaine in the liver. Elimination occurred via both blood and hepatic elimination. The model was validated using independently derived data. The model was scaled to humans and accurately predicted the cocaine levels following intranasal and inhalation administration. However, a poor fit was observed following intravenous administration. Future models incorporating non-constant blood flow and pharmacodynamics need to be developed.

Animals↗
PubMed1995

Psychometric properties of the MSPSS and NOS in psychiatric outpatients.

Prior research has demonstrated the utility of the Multidimensional Scale of Perceived Social Support (MSPSS) and the Network Orientation Scale (NOS) as measures of perceived social support among nonpsychiatric samples. The primary objective of this study was to determine whether these two scales can be used reliably among psychiatric outpatients, in particular those with schizophrenia or a major affective disorder. Subjects were 144 outpatients, aged 21 to 67 years, who completed the MSPSS and NOS. Results demonstrated high internal consistency for the MSPSS and adequate internal consistency for the NOS. In addition, convergent validity was demonstrated. Scores on both scales for these psychiatric outpatients were found to be lower as compared to "normals."

Adult↗
PubMed1993

Expressive characteristics of anxiety in depressed men and women.

This study was aimed at identifying the expressive, movement, and social behaviors associated with anxiety in the syndrome of major depression. The sample consisted of 97 hospitalized male and female depressed patients. Expressive and social behaviors were evaluated prior to treatment in a structured videotaped interview. Anxiety was measured using a multi-vantaged approach including doctor's rating, nurse's rating, patient self-report, and a separate video rating. Results indicate that anxiety was significantly associated with agitation, distressed facial expression, bodily discomfort, and poor social interaction in both sexes. Men and women differed in certain respects: anxiety was highly related to motor retardation in women only, and to hostility in men only. Differences in the pattern of expressive behavior between high and low anxious, depressed patients were clearly significant, and several were large enough to serve as clinical indicators. These findings help to characterize the expressive features of anxiety in the context of severe depression, and add to the growing literature on sex differences in depression.

Adult↗
PubMed1993

Anogenital warts in children.

Fourteen children presenting with anogenital (AG) warts and their close family members were studied; 28.6 and 8.3% of presenting children and other child household members, respectively, had non-genital cutaneous warts; 42.8% of children with AG warts had one or more adult household member with common hand warts. Fifty per cent of all mothers had subclinical cervical papilloma virus (PV) infection; only one male adult had subclinical PV infection of the penis without concurrent AG warts. Of the children with AG warts 42.8% had one or more adult household member with AG warts. Human papilloma virus (HPV) deoxyribonucleic acid (DNA), type 6/11 most frequently, was detected in 38.5% AG wart biopsies from children, and 67% AG wart biopsies from adults. HPV 31/33/35 was detected in 28.5% of cervical preneoplasias and type 6/11 in the one case of subclinical PV infection of the penile shaft. Detection of HPV types 6/11, 16/18, or 31/33/35 in AG warts in children was significantly associated with vertical (from an HPV-infected maternal birth canal during vaginal delivery) or sexual transmission of these warts (Fisher exact probability P = 0.031).

Anus Diseases↗
PubMed1993

Compliance with clinic attendance by outpatients with schizophrenia.

OBJECTIVE: The purposes of the study were to determine rates of compliance with appointments among patients with schizophrenia who had been treated for more than four years in an outpatient clinic, to explore reasons for missed appointments, and to determine whether treatment modalities affected compliance rates. METHODS: Chi square analysis was used to compare attendance rates over a 12-month period of 55 patients who were nonrandomly assigned to a monthly group and 56 patients who were nonrandomly assigned to be seen in individual treatment every one to two months. Patients were asked to give reasons for missed appointments. RESULTS: From 71 to 86 percent of the patients kept their clinic appointments each month. Forgetting the appointment and transportation difficulties were the most common reasons for nonattendance. Compliance rates of patients in the two treatment modalities differed during only three of the 12 months: during two of those months subjects in individual treatment had higher compliance rates than those in groups. CONCLUSIONS: The results suggest that treatment modality has little impact on compliance and that compliance may be increased by letter and phone prompts and by staff awareness of patients' problems such as transportation and finances.

Adult↗
PubMed1991

Physicians' recognition of and response to child abuse: Northern Ireland and the U.S.A.

There is a long history of professional and public concern with the problems of recognizing and reporting child abuse. The research reported here compares recognition of and response to potential abuse by physicians in Northern Ireland and the United States. An experimental study using vignettes in the USA and hospital data, showed that physicians' judgments were moderately affected by ethnic status (black-white) and socioeconomic status of the family, in addition to level of injury to the child. We conducted a comparative study to test whether the social cleavage based on religion (Protestant-Catholic in North Ireland), would affect the recognition of and response to child abuse by medical practitioners in North Ireland. While there was a slight tendency for responses to be affected by socioeconomic status and religion, the results were not statistically significant, as was true for the level of injury to the child. We also compared "diagnostic behavior," signs used to diagnose abuse and causal notions concerning abuse. Medical practitioners in the two countries differ with respect to (1) the amount and type of information desired about a case, and (2) the factors believed to "cause" abuse, but are in general agreement about the "signs" of abuse.

Child↗
PubMed1988

Sociodemographic and prior clinical course characteristics associated with treatment response in depressed patients.

A sociodemographic and clinical picture is presented of 82 depressed subjects who had an unequivocal response or lack of response to treatment with amitriptyline or imipramine. Patients with less severe depressive illness were found more likely to respond to treatment, while those with psychotic features were more likely to be treatment resistant. Sociodemographic and other prior and current clinical course variables were not predictive of treatment response in depressed patients.

Adult↗
PubMed1988

Men and bereavement.

Explore the source record for details and available documents.

Adaptation, Psychological↗
PubMed1987

Diagnosis and treatment of mixed mania.

In a study of 19 manic patients, the authors found that eight suffered from mixed mania, a condition in which depressive symptoms are found in the context of classic manic features. The presence of a mixed manic state predicted at least a slower and possibly a poor response to lithium therapy. The authors suggest that the delineation of a subgroup of mixed manic patients might help to identify potential lithium-resistant patients.

Adult↗
PubMed1986

Cerebrospinal fluid amine metabolites. Relationships with behavioral measurements in depressed, manic, and healthy control subjects.

We studied 99 hospitalized depressed, 14 manic, and 61 healthy control subjects and evaluated relationships during a drug-free baseline period between behavioral measures (postulated to be associated with brain norepinephrine, dopamine, and serotonin function) and metabolites of these neurotransmitters sampled from lumbar cerebrospinal fluid (CSF): 3-methoxy-4-hydroxyphenylglycol (MHPG), homovanillic acid, and 5-hydroxyindoleacetic acid. Depressed subjects with increased anxiety, agitation, somatization, and sleep disturbance were found to have significantly elevated concentrations of CSF MHPG; this relationship was not found in the healthy controls. A correlation between CSF MHPG level and an anxiety/agitation dimension measured in all subjects was statistically significant but explained a modest portion of the total variance. No consistent relationships were found between CSF MHPG and depression/retardation, hostility/interpersonal sensitivity, and global severity, nor did any of these measures correlate significantly with the levels of the other monoamine metabolites, although some trends were found. Other factors did not account for the relationships between CSF MHPG and some behavioral measures, including diagnostic subgroup, motor movement, age, sex, and premenopausal or postmenopausal status in women. Suggested relationships among drug treatment modality, eventual treatment outcome, behavioral and mood state at baseline, and these metabolite levels will require further analyses.

Bipolar Disorder↗
PubMed1985

Self-inflicted gunshot wounds: lethality of method versus intent.

The authors studied 30 patients treated at an urban trauma center for self-inflicted gunshot wounds, most or all of which would have been fatal without emergency treatment. About half the patients had used alcohol or drugs immediately before wounding themselves, and slightly more than half had experienced interpersonal conflict just before the incident. Thirteen of the 30 were women. Only nine were given diagnoses of major depressive episode or dysthymia; none of the patients had written suicide notes. These data indicate that the reported demographic and clinical characteristics of impulsive, violent self-injury must be reexamined.

Adolescent↗
PubMed1984

Mechanism of HgCl2 cytotoxicity in cultured mammalian cells.

Treatment of intact Chinese hamster ovary cells with HgCl2 produced a rapid, concentration-dependent induction of DNA single-strand breaks (SSB) as revealed by alkaline elution analysis. Direct addition of HgCl2 to cell lysates did not result in DNA strand breaks. HgCl2 treatment of cells also caused a rapid leakage of superoxide radicals that were detected in their media by measurement of the reduction of exogenously added cytochrome c. There was a linear relationship between the production of radicals and the induction of DNA strand breaks, and there were also excellent temporal correlations in these parameters. Addition of oxygen radical scavengers, such as the enzymes superoxide dismutase and catalase, to the extracellular media significantly reduced the extent of DNA damage caused by HgCl2 without a similar attenuation of its uptake into cells, as did the autoclaved enzymes. Similarly, addition of radical scavengers such as glycerol or ascorbate inhibited the DNA damage but also reduced the uptake of the metal by almost the same degree. Thus, because of secondary effects on uptake of the metal, the radical scavenger experiments could not address the importance of oxygen radicals in the DNA damage caused by HgCl2. SSB were enhanced when cells were treated with HgCl2 and diethylmaleate or diethyldithiocarbamate, agents that deplete cellular reduced glutathione or inhibit the intracellular activity of superoxide dismutase, respectively. Thus, DNA damage in cells rendered sensitive to radicals was greater when these cultures were subsequently treated with HgCl2. The binding of 203HgCl2 to the DNA of intact Chinese hamster ovary cells was also studied. These studies were made possible by the relatively high stability of Hg(II) interaction with DNA and by utilizing a gentle method of DNA isolation that minimized redistribution of intracellular Hg(II) complexes after cells were lysed. The amount of Hg(II) bound to DNA varied from approximately 7 to 35 Hg atoms per 10(4) base pairs (bp) at concentrations of HgCl2 that have been previously shown to produce between 1 SSB/10(7) bp and 1 SSB/10(6) bp. The Hg(II)-DNA adducts were relatively stable complexes, since they resisted treatment with 0.1 M EDTA and 1 M NaCl and were stable to precipitation of the DNA with ethanol and trichloroacetic acid. However, the Hg(II) was released from the DNA when it was degraded enzymatically to mononucleosides, suggesting that the Hg(II)-DNA bonds formed in the cell were not truly covalent and that the strength of Hg(II) binding to DNA depended upon polynucleotide structure.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1983

Plasma and erythrocyte electrolytes in affective disorders.

Plasma and erythrocyte sodium (Na+), total and free (ultrafiltrable) plasma magnesium (Mg2+) as well as erythrocyte magnesium were measured in patients with affective disorders and in healthy control subjects. Depressed and manic patients had higher total plasma Mg2+ than did hospitalized healthy control subjects, but concentrations of ultrafiltrable Mg2+ did not differ. Although erythrocyte Mg2+ was significantly elevated in the depressed subjects in comparison with that found in the non-hospitalized healthy controls, this difference was not seen between the depressives and the hospitalized healthy controls. Depressed, manic or healthy control subjects did not differ with respect to either plasma or erythrocyte.

Adult↗
PubMed1982

Behavioural measurement and drug response characteristics of unipolar and bipolar depression.

This research is part of the NIMH--CRB Collaborative Study on the psychobiology of depression. The main objective of the research programme is to test hypotheses concerning the interaction of neurobiological mechanisms and behaviour in the depressive disorders. Part I of the report describes the rationale and the overall approach to measuring behavioural state and outcome in the research programme. Part II reports on the results of applying the behavioural methods to a comparison of the clinical phenomenology of unipolar and bipolar depression. The behavioural patterns expressed during the episode by the two groups are different. Further, the two types are shown to react differently to treatment with tricyclic drugs, reinforcing the thesis that they are qualitatively distinct forms of the depressive disorders.

Antidepressive Agents, Tricyclic↗
PubMed1981

The demonstration, by immunofluorescence, of Legionella pneumophila organisms in human lung tissue embedded in epoxy resin.

Legionella pneumophila serogroup 1 has been demonstrated by indirect immunofluorescence in human lung tissue fixed in 10% formal saline and embedded in epoxy resin. The organism was visualised using Rabbit serogroup 1 antibody and Sheep anti rabbit fluorescein conjugate. The fluorescent labelled organism was found distributed throughout the tissue with focal areas in alveolar spaces and also visualised by electron microscopy in the same tissue. This method therefore enables specific identification of the L. pneumophila organism with the antiserum and also affords the opportunity of studying the bacterium ultrastructurally in the same tissue.

Epoxy Resins↗