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Biomedical subjects

C Thompson

Publications and source records attributed to C Thompson.

At least 253 records · Page 14Linked to original sources
PubMed1992

Limulus antilipopolysaccharide factor protects rabbits from meningococcal endotoxin shock.

Limulus antilipopolysaccharide factor (LALF), an 11.8-kDa peptide isolated from amebocytes of Limulus polyphemus, neutralizes meningococcal lipooligosaccharide (LOS)-induced gelation of limulus amebocyte lysate. Rabbits challenged with an LD90 of LOS (10 micrograms/kg) premixed with LALF in vitro (n = 10) had significantly higher mean arterial pressure, arterial pH, serum bicarbonate concentrations, and survival (90% vs. 8%, P = .005) than did rabbits challenged with LOS alone. Relative to untreated controls, rabbits pretreated with LALF intravenously (iv) at 1.2 mg/kg (n = 21) also had significant improvements in physiologic measurements and higher survival (52% vs. 8%, P = .003). Even when LALF (1.2 mg/kg iv) was given 1/2 h after LOS challenge, animals showed significant improvements in physiologic measurements and survival (33% vs. 8% in untreated controls P = .028). LALF-treated animals also had significantly lower circulating endotoxin activity and tumor necrosis factor concentrations. Thus, LALF attenuates the toxic effects of meningococcal LOS in rabbits even when administered after LOS challenge and deserves further evaluation as a potential therapeutic agent for treating gram-negative septic shock.

Animals↗
PubMed1992

Effect of a human immunoglobulin preparation for intravenous use in a rabbit model of meningococcal endotoxin-induced shock.

BACKGROUND AND METHODS: Endotoxin shock is mediated by various cytokines, including tumor necrosis factor. Treatment of patients with i.v. immunoglobulin has been shown to reduce the concentration of circulating cytokines. The purpose of this study was to determine the protective effects of immunoglobulin for i.v. use on meningococcal endotoxin-induced shock in a rabbit model. Experimental animals were challenged with i.v. meningococcal endotoxin (lipo-oligosaccharide) 10 micrograms/kg, and treated with either a 2-hr i.v. immunoglobulin infusion (400 mg/kg) or a similar saline infusion that was initiated 30 mins before endotoxin challenge. Control animals were challenged with saline alone. RESULTS: Compared with untreated control animals, pulse rate increased (p less than .007) and mean arterial pressure and serum bicarbonate concentrations decreased (p less than .02) in both experimental groups, but did not differ between immunoglobulin-treated and saline-treated animals (p greater than .05) at any time after the endotoxin challenge. Geometric mean serum endotoxin concentrations were significantly (p less than .03) lower in the immunoglobulin-treated animals at 60, 120, 180, 240, 300, and 360 mins after the endotoxin challenge. The geometric mean serum tumor necrosis factor level at 1 hr after the endotoxin challenge in the immunoglobulin-treated experimental animals was lower than in saline-treated animals (5.53 vs. 8.47 tumor necrosis factor enzyme-linked immunosorbent assay U/mL), but not significantly so (p greater than .05). Mortality rate was similar in both experimental groups; eight (67%) of 12 saline-treated experimental rabbits and seven (70%) of ten immunoglobulin-treated rabbits died. All untreated control animals survived 24 hrs. CONCLUSIONS: In this model of circulatory shock in rabbits, i.v. immunoglobulin: a) does not significantly alter the physiologic responses to endotoxin challenge; b) significantly reduces endotoxin concentrations; c) reduces tumor necrosis factor concentrations, but not significantly; and d) does not improve survival rate.

Analysis of Variance↗
PubMed1992

Bridging the gap between psychiatric practice and primary care.

The recognition and treatment of psychiatric illness in general practice is a skilled and difficult task and it is estimated that about 30% of psychiatric diagnoses may be missed. Patients whose illness is recognized are more likely to recover at follow-up than those whose illness is missed, demonstrating the importance of adequate training in recognizing psychiatric illness. Many general practitioners find difficulty in using tricyclic antidepressants to treat depression. The usual dose is lower than research evidence accepts as therapeutic and side effects often result in patient refusal to take a full dose. Additionally, the tricyclics are highly toxic in overdose. Many general practitioners in the UK are wary of new treatments because of previous experience of rare side effects leading to withdrawal of some new drugs. However, prescriptions of the selective serotonin reuptake inhibitors (SSRIs) for depression are gradually increasing here and in other countries such as the USA, France and Canada, where the SSRIs as a class account for upwards of 30% of new antidepressant prescriptions. The SSRIs are well suited to general practice; they have a greater therapeutic index than tricyclics, are much safer in overdosage, and have a different range of side effects (mainly nausea) which are better tolerated by patients at therapeutic doses. Furthermore, the SSRIs generally do not require dosage escalation for most patients and evidence indicates that they are effective in the treatment of depression associated with anxiety and insomnia. The safety and efficacy of the new SSRI sertraline has been established in comparative trials versus amitriptyline, imipramine and dothiepin (Reimherr et al., 1990; Cohn et al., 1990; Fontaine, 1991; Langdon, 1991).(ABSTRACT TRUNCATED AT 250 WORDS)

1-Naphthylamine↗
PubMed1992

Colorectal cancer screening: optimal compliance with postal faecal occult blood test.

Five approaches to postal faecal occult blood test (FOBT) were compared in a population sample of 966 subjects collected from three general practitioner patient lists in Southern Sydney. The highest compliance rate (59.8%) was achieved by a method using a general practitioner letter, with no dietary restrictions with FOBT. This was also the least expensive method. Compliance rates can be affected by incorrect address information and screenees not considering themselves to be current patients. An explanation from the family doctor addressed personally to the patient with an enclosed FOBT kit can achieve high compliance rates.

Aged↗
PubMed1992

Neuropsychological and psychiatric abnormalities in myalgic encephalomyelitis: a preliminary report.

Ten patients attending one general medical hospital clinic who fulfilled operational criteria for the diagnosis of myalgic encephalomyelitis (ME) and with a history longer than three months, underwent a series of standardized neuropsychological and psychiatric tests. Nine were able to complete the tests and were individually matched with a normal control group for age, sex, educational background and premorbid intelligence. The ME subjects showed inferior performance to the controls on two tests of verbal memory. Their personality scores displayed less extraversion and less psychoticism. This is the first report of objective neuropsychological abnormalities in patients with ME, suggesting a discrete deterioration of short-term memory. The findings may also suggest a concurrent psychiatric component of the condition, but the direction of causality remains to be clarified.

Anxiety Disorders↗
PubMed1991

Prognostic significance of carcinoembryonic antigen in colorectal carcinoma. Serum levels before and after resection and before recurrence.

The use of carcinoembryonic antigen was evaluated in 425 patients with a mean follow-up of 48 months. The preoperative and postoperative carcinoembryonic antigen levels were predictive of recurrence and survival independent of the tumor stage. In a multivariate regression analysis of age, location, tumor stage, and preoperative and postoperative carcinoembryonic antigen levels, the latter three factors were significant prognostic variables with respect to the adjusted survival. Recurrent disease was found in 42% of patients, excluding patients with stage IV disease. The carcinoembryonic antigen level at recurrence was greater than 5 ng/mL in 79% of the patients and in 89% of the intra-abdominal recurrences. Carcinoembryonic antigen level at recurrence was not predictive of postrecurrence survival except in the subgroup of locoregional disease. The life span in patients with liver and lung metastases was not influenced by carcinoembryonic antigen level at recurrence. Preoperative and postoperative carcinoembryonic antigen levels can indicate a poorer prognostic group of patients with colorectal cancer who may benefit from adjuvant treatment. The carcinoembryonic antigen at recurrence can be used effectively to diagnose intra-abdominal recurrences and project survival after development of local/regional disease.

Aged↗
PubMed1991

A double-blind crossover study of oral xamoterol in postural hypotension due to diabetic autonomic neuropathy.

Recent reports have suggested that xamoterol, a beta 1 adrenoceptor partial agonist with 43% intrinsic sympathomimetic activity improves symptomatic postural hypotension in patients with primary autonomic failure. To evaluate the use of xamoterol in eleven insulin dependent patients with diabetes mellitus who had postural hypotension (over 20 mmHg systolic blood pressure) secondary to autonomic neuropathy, we performed a double-blind, randomized, placebo controlled crossover study with xamoterol (200 mg bd orally) for 1 month. Treatment with xamoterol raised supine systolic blood pressure by 11 mmHg but a reduced standing systolic blood pressure by 11 mmHg with an increase in the standing-supine systolic blood pressure difference. No significant differences were observed in symptom score, HbA1 or plasma glucose. We conclude that oral xamoterol raises supine systolic blood pressure but paradoxically lowers standing systolic blood pressure further in insulin dependent diabetes mellitus. Xamoterol is unlikely to be of value in the management of postural hypotension in diabetic patients with autonomic neuropathy.

Adrenergic beta-Agonists↗
PubMed1991

Psychological and behavioral benefits of a stress/type A behavior reduction program for healthy middle-aged army officers.

Twenty army officers who participated in a stress/type A behavior reduction program and a comparison group of 17 officer nonparticipants volunteered to undergo a battery of psychological and behavioral tests before and after the program. Following the program, participants displayed a significantly greater reduction in average daily caloric intake and levels of perceived stress, anxiety, hostility, depression, psychological distress, and type A behavior as compared to the officers who did not participate in it. Given the fact that most of these psychological and behavioral factors have been found in previous studies to be related to an increased risk for coronary artery disease, it seems that the changes reported by the participants in the program are potentially healthful.

Adaptation, Psychological↗
PubMed1991

Effect of polymyxin B on experimental shock from meningococcal and Escherichia coli endotoxins.

Meningococcemia is the most frequent cause of septic shock in healthy children. To determine whether polymyxin B (PMB) might improve mortality from meningococcal shock, its protective activity was evaluated in rabbits challenged with an LD90 of meningococcal lipooligosaccharide (LOS) and compared with an LD80 of Escherichia coli O111:B4 lipopolysaccharide (LPS). PMB (5 mg/kg) administered intravenously 30 min before meningococcal LOS challenge had no significant effect on heart rate, mean arterial pressure, serum bicarbonate, serum tumor necrosis factor (TNF) levels, or survival relative to controls. However, PMB premixed with LOS in vitro increased serum bicarbonate levels (P less than .05) and improved 24-h survival (P less than .05). In contrast, PMB given before E. coli LPS challenge increased serum bicarbonate levels, decreased TNF levels, and improved 24-h survival (all, P less than .05). In vitro studies confirmed that PMB at 10 micrograms/ml neutralized E. coli LPS but not meningococcal LOS activity. Thus, pretreatment with PMB apparently protects rabbits against shock induced by E. coli LPS but not by meningococcal LOS.

Animals↗
PubMed1991

Preliminary evaluation of "Clearview Chlamydia" for the rapid detection of chlamydial antigen in cervical secretions.

Clearview Chlamydia (Unipath) is a rapid monoclonal antibody based latex immunodiffusion test for detecting chlamydial antigen in endocervical specimens. The assay does not require specialised equipment or extensive training and takes less than 30 minutes from sample to results. The clinical performance of Clearview Chlamydia was evaluated with 478 paired endocervical swabs from patients attending a genitourinary medicine clinic. In the first part of the study, 221 non-randomised specimens were tested by cell culture (1st swab) and Clearview (2nd swab) whereas in the second part of the study 257 randomised swabs were examined by Clearview, cell culture and immunofluorescence. The overall prevalence of chlamydial infection was 8.8% and the sensitivity, specificity, positive and negative predictive values for Clearview were 85.7%, 99.1%, 90% and 98.6%. The test requires further evaluation to establish its role in the management and control of chlamydial infection.

Antigens, Bacterial↗
PubMed1991

Activated oxygen species do not mediate hypercapnia-induced cerebral vasodilation in newborn pigs.

In newborn pigs, vasodilation in response to hypercapnia is dependent on prostaglandin (PG) H synthase. We investigated the contribution of activated oxygen by-products to hypercapnia-induced PGH synthase-dependent dilation of pial arteries and arterioles in anesthetized newborn pigs. Activated oxygen species were generated on the cerebral surface using xanthine oxidase and hypoxanthine. Catalase, H2O2, and iron or N-(2-mercaptopropionyl)-glycine (MPG) were used to separate effects of superoxide anion and hydroxyl radical. All the activated oxygen species tested caused vasodilation of both arteries and arterioles. Vasodilation to all activated oxygen species was largely reversible with only the hydroxyl radical encouraging combination of xanthine oxidase, hypoxanthine, H2O2, and FeCl3, causing significant dilation 20 min after removal of treatment. Cotreatment with MPG blocked this residual dilation. Neither pretreatment with the extracellular superoxide anion radical scavenger, superoxide dismutase (SOD), the intracellular superoxide anion radical scavenger, Tiron, the H2O2 scavenger, catalase, nor hydroxyl radical scavengers, dimethyl sulfoxide (DMSO) and MPG, altered vasodilation of pial arteries or arterioles in response to hypercapnia. Furthermore, the increase in cerebral prostanoid synthesis in response to hypercapnia was not affected by pretreatment with SOD, Tiron, catalase, DMSO, or MPG. We conclude that the progressively reduced forms of oxygen that would be produced during PGH synthase metabolism of arachidonic acid can dilate pial arteries and arterioles of newborn pigs. However, these activated oxygen species are not responsible for the vasodilation to hypercapnia in the newborn pig, suggesting that eicosanoids cause the dilation.

Animals↗