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Biomedical subjects

G Clarke

Publications and source records attributed to G Clarke.

At least 73 records · Page 4Linked to original sources
PubMed1993

Three forms of stress in Cambodian adolescent refugees.

Sixty-nine Cambodian adolescents and young adults were interviewed to determine their experience as children surviving the Pol Pot regime (1975-1979); their first-year experience of resettlement in this country; and their experience of stressful events during the past year. Current DSM-III-R diagnostic status was also determined. A strong relationship between earlier war trauma, resettlement strain, and symptoms of posttraumatic stress disorder (PTSD) was found. In contrast, the strongest relationship with depressive symptoms was found for recent stressful events. These results are discussed in light of current findings from stress and PTSD research.

Adolescent↗
PubMed1993

A 6-year follow-up study of Cambodian refugee adolescents traumatized as children.

Seventy-three percent of a sample of 46 Cambodian youth interviewed in 1984 and 1987 were reinterviewed in 1990 as part of a pretest for a multisite study of Cambodian refugee trauma now under way. An additional sample of convenience of 38 youth were also interviewed to determine reliability and validity of the diagnostic instruments chosen for the larger study. The DSM-III-R diagnosis of post-traumatic stress disorder (PTSD) was found to persist, but the symptoms appeared less intense over time. In contrast, the prevalence of depression dropped markedly since 1987. Subjects remained largely free of comorbid conditions. Diagnostic reliability and validity were satisfactory. The follow-up sample appeared to be functioning well despite their PTSD profiles. The findings are discussed in light of several current controversies surrounding the concept and measurement of PTSD.

Adolescent↗
PubMed1993

Effects of the kappa-opioid agonist U50,488 on parturition in rats.

1. The effects of the kappa-opioid agonist U50,488 on parturition were studied in the rat. 2. Given directly after the birth of the second pup U50,488 (5 mg or 10 mg kg-1, i.p.) delayed the birth of the subsequent 4 pups by ca. 100 min, acting like morphine (10 mg kg-1, i.p.). In controls given the vehicle i.p., the birth of the 4 pups after treatment took 45.4 +/- 4.6 min. The effects of U50,488 could be prevented by simultaneous naloxone injection (10 mg kg-1). Injection of either U50,488 or morphine at 1 mg kg-1, i.v. also significantly delayed parturition. The effects of U50,488 but not of morphine were fully prevented by preinjection with nor-binaltorphimine (0.5 mg kg-1, i.v.) showing selective kappa-opioid receptor-mediated inhibition by U50,488 of established parturition. 3. In rats with an indwelling jugular venous cannula, i.v. injection of U50,488 (5 mg kg-1) after the birth of the second pup slowed parturition in a similar way to i.p. injection and significantly reduced blood plasma oxytocin concentration measured by radioimmunoassay compared with vehicle-injected controls. 4. Bolus i.v. injections of oxytocin (4 mu once per 5 min) significantly reduced the delay in parturition caused by i.v. U50,488, but continuous i.v. infusion of oxytocin (4 mu 5 min-1) was less effective. 5. Since i.v. oxytocin did not immediately reverse the effects of U50,488 on parturition, direct effects of U50,488 on isometric uterine contractions in vitro were sought. U50,488 inhibited spontaneous or oxytocin-stimulated contractions of uteri from rats within 24 h after parturition in a dose-related manner; the inhibitory effect was not naloxone-reversible.6. Thus U50,488 inhibited established parturition in the rat in a Kappa-opioid selective manner by reducing oxytocin secretion. The inhibitory effect may well have been potentiated by a direct non-opioid depressant action on contractile activity of the uterus.

3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cycloh↗
PubMed1993

Clinical high resolution skeletal single photon emission tomography using a triple-headed gamma camera.

Planar skeletal scintigraphy has become established as a standard diagnostic test performed within the nuclear medicine department. Since the 1970s good quality images have been produced using an Anger gamma camera and 99Tcm-labelled diphosphonates. Single photon emission tomography (SPET) has improved the sensitivity of detection and the ability to localize bony pathology, particularly benign bone disease in the spine. Recently multi-detector gamma cameras dedicated to SPET have become available. One such system, the Toshiba GCA-9300A, has been used to perform routine clinical skeletal SPET in 81 patients. Good quality images have been obtained using an 8 min acquisition in the axial skeleton and a 16 min acquisition protocol in the peripheral skeleton. Multiple sites can be tomographed in the same patient during the same examination using two or more 8 min acquisitions. Such a multi-detector gamma camera offers advantages over the standard single-headed rotating camera for skeletal SPET in terms of both imaging time and image quality. A cost analysis was performed which demonstrated that the additional cost of purchasing such a multidector gamma camera was less than 30.00 pounds per SPET study.

Bone Neoplasms↗
PubMed1991

The effect of circulating antigen and radiolabel stability on the biodistribution of an indium labelled antibody.

This study has investigated two of the main problems with radiolabelled antibody imaging, the formation of circulating immune complexes (I.C.) and the non specific binding of radiolabel to the antibody molecule. Patients undergoing immunoscintigraphy with 111In labelled monoclonal antibody ICR2 were divided into three groups who received either the radiolabelled antibody alone (control, n = 12), the radiolabelled antibody which was incubated with the chelating agent diethylene triamine pentacetic acid (DTPA) prior to size exclusion chromatography (n = 6) or whose injectate was treated with DTPA and cold MAb administered intravenously prior to radiolabelled MAb administration (n = 6). Radiolabelled antibody uptake in abdominal organs was measured by region of interest analysis using a gamma camera with online computer and that in tumour and normal tissues by gamma well counting of biopsies. Circulating antigen and immune complex was measured by high pressure liquid chromatography (HPLC). The sensitivity of tumour imaging and the tumour uptake of radiolabelled antibody was not significantly different between the groups. Patients with high circulating antigen levels developed high levels of circulating immune complex but also had high tumour uptakes of radiolabelled antibody. Administration of cold MAb increased the splenic, but did not effect the tumour uptake of radiolabelled antibody and only minimally reduced levels of circulating immune complex. Chelate administration reduced the urinary excretion of radioactivity but increased the liver uptake of radioactivity. These results have shown that successful antibody imaging can be carried out despite high levels of circulating antigen, that large doses of unlabelled antibody are required to prevent immune complex formation and that removal of non specifically bound 111In does not reduce the liver uptake of radioactivity.

Aged↗
PubMed1991

Perforation in patients with bleeding ulcer.

Twelve patients developed perforation after haemorrhage in a consecutive series of 840 cases admitted for bleeding chronic peptic ulcer. Death occurred in 3 of the 9 cases with duodenal ulcer and 1 of the 3 cases with gastric ulcer. There were 5 giant and 4 kissing duodenal ulcers and all 3 cases with gastric ulcer had a giant ulcer. The 12 patients were similar to the rest of the series in terms of ulcer site and shock on admission but were older and in poorer medical condition, more had ingested analgesics, more had giant ulcers and the mortality was greater (33% vs 6%). Giant ulceration was the only risk factor of potential clinical value as a predictor of the danger of ulcer perforation. One death occurred in 8 cases treated by early definitive surgery, suggesting this to be the treatment of choice for this unusual complication of peptic ulcer.

Contraindications↗
PubMed1990

Immunoscintigraphy of colorectal cancer with an antibody to epithelial membrane antigen (EMA).

Immunoperoxidase staining of LICR-LON M8, a mouse monoclonal antibody reactive with epithelial membrane antigen, showed a strong reaction with colorectal cancer. This finding prompted an immunoscintigraphic study of colorectal cancer patients using this antibody. Sixteen patients had external gamma scintigraphy after intravenous injection of indium 111-labeled M8. Positive scans were obtained in 11 of the 13 patients with primary colorectal cancers, and 2 of the 3 patients with recurrent tumors. The high indium 111 background in the liver prevented the detection of hepatic metastases in 5 patients. Twelve patients had samples taken of tumor, normal colon, and venous blood at the time of surgery. The ratio of labeled antibody uptake in tumor to that of blood was 5.1 (+/- 3.6 S.D.), which was significantly different (P = 0.001) to that of the similar ratio for normal colon (2.0 +/- 1.6 S.D.). The tumor to normal colon uptake ratio was 2.6 (+/- 1.3 S.D.). These results suggest a specific uptake of indium 111-labeled M8 by colorectal cancer.

Aged↗
PubMed1990

Changes in regional ventilation and perfusion of the lung after endoscopic laser treatment.

To determine whether endoscopic laser treatment improves both ventilation and perfusion in patients with advanced lung cancer, krypton-81m ventilation and technetium-99m labelled macro-aggregate perfusion scanning was performed immediately before and two or four days after treatment in a consecutive series of 28 patients. Twelve patients had not received any other treatment before laser therapy and 16 had undergone previous treatments that included radiotherapy. Ventilation and perfusion were quantified by expressing the number of counts in the affected lung as a percentage of the total counts. Ventilation and perfusion improved after laser treatment in 23 patients (82%). The mean ventilation score in the affected lung rose by 50% (p less than 0.001) and the mean perfusion score rose by 24% (p less than 0.001). Incremental changes in ventilation and perfusion scores were positively correlated (r = 0.80). Mean spirometric values, six minute walking distance, the Karnofsky performance index, and breathlessness and wellbeing scores also improved significantly. Patients with main bronchial obstruction who had had no radiotherapy showed the most striking improvements. It is concluded that the removal of intraluminal tumour from the bronchial tree leads to matched improvements in ventilation and perfusion in most patients and that this is associated with valuable improvement in symptoms.

Adult↗
PubMed1990

Intra-abdominal pressure and renal function after surgery to the abdominal aorta.

It has been suggested that an elevated intra-abdominal pressure (IAP) can impair renal function. In a prospective longitudinal study, the IAP of 42 patients admitted to an intensive care unit after abdominal aortic surgery was monitored. When compared with the other patients, the 22 patients (53%) who developed renal impairment had higher IAP (17.8 +/- 6.0 mmHg versus 14.1 +/- 4.8 mmHg; P less than 0.01) and APACHE II scores (15.6 +/- 6.0 versus 9.8 +/- 4.6; P less than 0.01). Each of the 10 patients who were re-explored because of haemodynamic instability and oliguria had an IAP of greater than 18 mmHg (positive predictive value = 85%, negative predictive value = 62%). Following re-exploration, the urinary output increased by 115 +/- 40 mL/h (P less than 0.01), and the IAP decreased by 10 +/- 3 mmHg (P less than 0.01). Although it is concluded that an IAP greater than 18 mmHg is a significant risk factor for the development of impaired renal function, it was not possible to prove a causal relationship between these events. Nevertheless, such a relationship has been demonstrated in animal and human models.

Abdomen↗
PubMed1989

A three-year follow-up of Cambodian young people traumatized as children.

Twenty-seven Cambodian young people, who were severely traumatized at ages 8 to 12, were followed up 3 years after an original study. A structured interview and self-rating scales showed that post-traumatic stress disorders (PTSD) were still highly prevalent (48%). Depression existed in 41%. Those with PTSD differed significantly from those without PTSD on the Global Adjustment Scale, the Social Adjustment Scale, the Beck Depression Inventory, and the Impact of Event Scale. Eight subjects had PTSD at both interviews, while 11 had none at either time. Eight showed a variable course. Avoidance behavior was highly prevalent, even among those without PTSD diagnosis. Although functioning relatively well, these youths continued to show symptoms related to their trauma of 8 to 12 years before.

Adolescent↗