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Biomedical subjects

C Thomas

Publications and source records attributed to C Thomas.

At least 685 records · Page 38Linked to original sources
PubMedDate not supplied

No effect of prophylactic treatment with metoprolol on cerebrovascular CO2 reactivity in migraineurs.

The prophylactic effect of metoprolol in the treatment of migraine is well known, but its mode of action is still unclear. In the past, increased CO2 reactivity has been reported as one pathognomic finding in interictal migraineurs. Using transcranial Doppler we assessed CO2 reactivity in 20 migraineurs before and 3 h after the first intake of 50 mg metoprolol, and subsequently twice after 1 and 8 weeks of continuous therapy with 150 mg metoprolol/d. Before initiation of therapy, migraineurs as a group had increased CO2 reactivity (p=0.07) compared to 20 age- and sex-matched volunteers. While treatment with metoprolol has been reported to affect amplitudes of increased contingent negative variation or visual evoked potentials in interictal migraineurs, it had no influence on enhanced CO2 reactivity in the present study. Moreover, the pretreatment value of CO2 reactivity did not correlate with the clinical efficacy of metoprolol after a 2-month treatment period.

Adrenergic beta-Antagonists↗
PubMedDate not supplied

Effect of intravenous platelet-activating factor on bovine pulmonary mast cells.

The effect of platelet-activating factor (PAF) on bovine pulmonary mast cells (MCs) was investigated in calves aged 1-4 months. PAF was administered over a 5-min period at a rate of 50 ng/kg/min to six animals, which were killed approximately 10 min later. No macroscopical lesions were observed in the lung tissue of five control calves. On semi-thin toluidine-blue stained sections, MC cytoplasm showed profuse deep-blue granulation. In the lung tissues of PAF-treated calves, striking interstitial, alveolar and interlobular oedema and emphysema were observed. MC granules occurred at the periphery of the cytoplasm and MC nuclei were easily detectable. Moreover, the number of granules in the MC cytoplasm was remarkably low. A few granules with some metachromatic material were sometimes detected outside the cell limits. Ultrastructurally, the matrix pattern of the MC granules in lung tissues of control calves was either amorphous or granular. In lung tissues of the PAF-treated calves, the granular matrix pattern was pronounced, varying from fine- to coarse-grained, and the MCs were of reduced size, with many filiform processes and exocytotic vesicles. These findings indicate that pulmonary MC degranulation was induced by PAF in healthy calves.

Animals↗
PubMedDate not supplied

[Myositis ossificans following extensive burns].

A report on a case of myositis ossificans following 50-60% burns (second to third-degree) on the trunk and extremities with periarticular localization of the ossification at the hip and knee joints. In terms of its extent and localization the ossification is primarily similar to post-paraplegic ossification of soft tissues.

Burns↗
PubMedDate not supplied

Medicine, gender, and disability: disabled women's health care encounters.

In this article I examine the intersection of gender and disability in the medical arena by considering disabled women's experiences of receiving health care in the United Kingdom. Drawing on the "social model of disability," I focus on the attitudes and practices of doctors. I use two sources of qualitative data: (i) 68 disabled women's narratives gathered in the United Kingdom in 1996-1997; (ii) interviews with 17 disabled women regarding their reproductive experiences in the United Kingdom. I suggest that disabled women health service users are at risk of experiencing oppressive medical practices because two forces of oppression appear to be frequently, and interactively, in play: patriarchy and disablism.

Attitude of Health Personnel↗
PubMedDate not supplied

The acoustic reflex in children without an hermetic seal.

In clinical practice with children, the hermetic seal is either often not obtainable or is lost before acoustic reflex measures are obtained. In a recent study, Surr and Schuchman (Archives of Otolaryngology 102, 160--161, 1976.) found that in the majority of cases reflex thresholds could be measured in adults with normal middle ears in the absence of an hermetic seal. This study was designed to find out whether the conclusions of Surr and Schuchman could be extended to children. Sealed and unsealed reflexes were compared in 30 children, ages 3 to 7, with normal middle ears. Results indicated that: (1) approximately two-thirds of the children demonstrated reflexes in the unsealed condition; (2) differences between sealed and unsealed reflex thresholds were not clinically significant; (3) in most cases, unsealed reflexes were measurable at all frequencies or at none; (4) neither size of ear canal volume nor amplitude of the sealed reflex at 10 dB SL seemed to be related to the presence or absence of the unsealed reflex. It was concluded that reflex thresholds obtained in the absence of an hermetic seal may be considered valid but the absence of an unsealed reflex should not be considered diagnostically significant.

Acoustic Impedance Tests↗
PubMedDate not supplied

Psychological problems reported by young adults who were burned as children.

This study assessed long-term psychosocial sequelae of young adult pediatric burn survivors. Subjects were 101 young adults (43 females and 58 males) between the ages of 18 and 28 years who were at least 2 years (average, 14 years) postburn at least 30% TBSA (mean = 54 +/- 20%). Educational status was 25% high school dropouts, 28% high school graduation only, 32% some college, and 5% completed college. Seventy-seven percent either worked or attended school; 28% had had a long-term partner. When assessed by Achenbach's Young Adult Self-Report (YASR) scale and compared with its published reference group, the males reported differences only in the somatic complaints, but the females endorsed significantly more externalizing and total problems, specifically withdrawn behaviors, somatic complaints, thought problems, aggressive behavior, and delinquent behavior. Despite these problems suffered by some female pediatric burn survivors, the overall outcome revealed that most pediatric burn survivors are making the transition into adulthood with minimal unexpected difficulty.

Adaptation, Psychological↗
PubMedDate not supplied

Alterations in plasma oxidative stress markers after laparoscopic operations of the upper and lower abdomen.

The patient's position during laparoscopic surgery can have a clinically relevant effect on lower limb and splanchnic circulation; this factor has not yet been investigated with respect to oxidative stress markers. In order to assess this effect, a prospective clinical trial was designed wherein 2 groups of patients were studied. In group A, 15 patients underwent upper abdominal nonhepatobiliary operations (13 modified Nissen fundoplications and 2 Taylor vagotomies) in the head-up position. In group B, 15 patients underwent lower abdominal operations (10 laparoscopic colectomies and 5 inguinal hernia repairs) in the head-down position. The pneumoperitoneum was maintained at 14 mm Hg in all cases. Plasma concentrations of thiobarbituric-acid reactive substances (TBARS), a marker of lipid peroxidation, plasma total antioxidant status (TAS), and serum uric acid concentrations were measured preoperatively, 5 minutes after deflation of the pneumoperitoneum, and 24 hours postoperatively. Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) serum activities were measured preoperatively and 24 hours postoperatively. In group A, there was a significant increase in TBARS levels (p<0.005) immediately after deflation of the pneumoperitoneum and a significant decrease in TAS and uric acid levels (p<0.005) in the first postoperative day. There was also a significant postoperative elevation in both ALT and AST activities (p<0.001). In group B, no significant increase was found in postoperative TBARS or transaminase levels. TAS and uric acid levels decreased significantly in the first postoperative day (p<0.05) and (p<0.005, respectively). In conclusion, these results show that a combination of pneumoperitoneum and the head-up position causes significant increase in lipid peroxidation, decrease in plasma TAS, and increase in transaminases. The mechanism responsible for these events could be the low-flow ischemia-reperfusion syndrome induced by the pneumoperitoneum and aggravated by the head-up position.

Adult↗
PubMedDate not supplied

Development of a community nurse-led continence service.

Extrapolations from prevalence studies suggest that on average 56,000 adults experience urinary incontinence in Glasgow, a third of whom will have been incontinent during the last week. A review by a multidisciplinary health gain commissioning team concluded that existing continence services in Glasgow had developed opportunistically and that problems exist, e.g. prescription of products without full assessment of continence problems. In response to this situation, a new community nurse-led continence service was introduced in 1995. This article describes the development and evaluation of this new service. For the past 3 years the service has employed five staff nurses and a physiotherapist. The team is solely employed to promote continence. It carries out assessments both in nursing and residential homes and community clinics. The planned evaluation will assess the effectiveness of this team in promoting continence and the future demand for continence nurse-led services.

Adult↗
PubMedDate not supplied

Free radical inactivation of rabbit muscle creatinine kinase: catalysis by physiological and hydrolyzed ICRF-187 (ICRF-198) iron chelates.

Creatine kinase is a sulfhydryl containing enzyme that is particularly susceptible to oxidative inactivation. This enzyme is potentially vulnerable to inactivation under conditions when it would be used as a diagnostic marker of tissue damage such as during cardiac ischemia/reperfusion or other oxidative tissue injury. Oxidative stress in tissues can induce the release of iron from its storage proteins, making it an available catalyst for free radical reactions. Although creatinine kinase inactivation in a heart reperfusion model has been documented, the mechanism has not been fully described, particularly with regard to the role of iron. We have investigated the inactivation of rabbit muscle creatine kinase by hydrogen peroxide and by xanthine oxidase generated superoxide or Adriamycin radicals in the presence of iron catalysts. As shown previously, creatine kinase was inactivated by hydrogen peroxide. Ferrous iron enhanced the inactivation. In addition, micromolar levels of iron and iron chelates that were reduced and recycled by superoxide or Adriamycin radicals were effective catalysts of creatinine kinase inactivation. Of the physiological iron chelates studied, Fe(ATP) was an especially effective catalyst of inactivation by what appeared to be a site-localized reaction. Fe(ICRF-198), a non-physiological chelate of interest because of its putative role in alleviating Adriamycin-induced cardiotoxicity, also catalyzed the inactivation. Scavenger studies implicated hydroxyl radical as the oxidant involved in iron-dependent creatine kinase inactivation. Loss of protein thiols accompanied loss of creatine kinase activity. Reduced glutathione (GSH) provided marked protection from oxidative inactivation, suggesting that enzyme inactivation under physiological conditions would occur only after GSH depletion.

Animals↗
PubMedDate not supplied

Comparative in vitro binding characteristics and biodistribution in tumor-bearing athymic mice of anti-ovarian carcinoma monoclonal antibodies.

The interactions of four monoclonal antibodies (OV-TL 3, OV-TL 16, OV-TL 30 and OC 125) with ovarian carcinoma cells (NIH: OVCAR-3) were compared in vitro as well as in a nude mouse model. The affinity constants of the antibodies ranged from 1.0 X 10(9) M-1 (OC 125) to 3 X 10(9) M-1 (OV-TL 30). The cell binding kinetics of the antibodies were studied in vitro: OV-TL 30 associated fastest (50% binding after 25 min), OV-TL 3 and OV-TL 16 associated more slowly (50% binding after 75 min), while the association of OC 125 was slowest (50% binding after 120 min). Dissociation rates of the antibodies also differed: OC 125 displayed the lowest dissociation rate (t1/2 = 360 min). The OV-TL antibodies showed a faster, biphasic dissociation characteristic. The biodistribution of the radioiodinated antibodies in NIH:OV-cAR-3 xenograft-bearing athymic mice, following intravenous injection, was compared. Highest tumor accumulation 48 h p.i. was found with OV-TL 3 (13.3 +/- 2.1% ID/g) and OV-TL 16 (11.0 +/- 2.0% ID/g), while the uptakes of OV-TL 30 and OC 125 were markedly lower (4.9 +/- 0.9% and 6.0 +/- 0.9% ID/g, respectively). The fact that in this experimental model the in vivo tumor accumulation of OV-TL 3 and OV-TL 16 was approximately twice as high as the tumor accumulation of OC 125 could not be fully ascribed to parameters of the antibodies determined in vitro (immunoreactive fraction, affinity constant, antigen density, association and dissociation rate). It is suggested that the antibodies OV-TL 3 and OV-TL 16 are suitable tools for clinical radioimmunodetection of ovarian carcinomas.

Animals↗
PubMedDate not supplied

Monoclonal antibodies against ovarian carcinoma-associated antigens, raised by immunization with cyst fluids.

Intrasplenic immunization with ovarian tumour derived cyst fluids was used to generate monoclonal antibodies (Mabs) against human ovarian carcinomas. Seven Mabs were characterized immunocytochemically using indirect immunofluorescence assays (IFA) on frozen sections of gynaecologic tumours (n = 85), non-gynaecologic tumours (n = 50), normal human tissues (n = 66), and on 8 ovarian carcinoma cell lines. The Mabs reacted with 67-96% of 49 ovarian carcinoma tissues tested. Although 6 out of 7 Mabs showed slight cross reactivity with some endometrial, cervical, and oviductal carcinomas, little reactivity with non-gynaecologic tumours or normal tissues was found. Based on immunoelectronmicroscopy, all the antigenic determinants defined by the Mabs appeared to be associated with the tumour cell membrane. Among the seven Mabs, OV-TL 16 (IgG1 subclass) and OV-TL 23 (IgM class) reacted positively with 96% and 82% of the ovarian carcinomas respectively. Staining of 100% of the ovarian carcinomas examined (n = 49) could be achieved by combining OV-TL 16 with 23, as also by other combinations of the Mabs. It is concluded that a panel of these newly developed Mabs may be suitable for diagnostic purposes in histopathology.

Antibodies, Monoclonal↗