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Biomedical subjects

J Chamberlain

Publications and source records attributed to J Chamberlain.

At least 127 records · Page 7Linked to original sources
PubMed1988

Transcutaneous oxygen monitoring as an indication of prognosis in critical ischaemia of the lower limb.

Critical ischaemia in the chronically ischaemic limb has proved difficult to define both in clinical and objective terms. This has meant that assessment of patients has in the past relied heavily on the angiographic appearances of the vessels which is also an unreliable technique. Attempts have been made to define critical ischaemia objectively in terms of the ankle systolic pressure but recent studies have shown that although the definition produced in 1982 was highly specific, the sensitivity was low with many patients with the clinical features of critical ischaemia having ankle pressures which were higher than the recommended values. Recently the transcutaneous measurement of oxygen tension has been used to assess patients with peripheral vascular disease and has proved of use in assessing distal tissue perfusion in chronically ischemic limbs. This study compares ankle systolic pressure measurements with the transcutaneous oxygen tension results from the ischaemic foot with the patient sitting and found that the latter gave a more accurate guide to the severity of ischaemia and a more accurate prediction of the short-term results in individual cases.

Ankle↗
PubMed1988

Glycosylated haemoglobin: an index of glucose control in pancreatic islet transplanted rats.

In this study we have measured glycosylated haemoglobin in the blood of 22 rats made diabetic with streptozotocin. This significantly increased from a normal level of 1.6 +/- 0.2% to reach a maximum, plateau level, of 6.6 +/- 0.3% at 45 days. At this time, 16 of these animals were given intra-portal transplants of purified isologous pancreatic islets. By varying the number of islets transplanted, animals were produced with normal blood glucose levels on random sampling, but with a spectrum of glucose control as measured by the glucose tolerance test. The glycosylated haemoglobin level was also measured at 30, 60 and 120 days post transplantation. This was significantly reduced (in some cases back to normal) and at 60 and 120 days there was a significant correlation (p less than 0.001) between glycosylated haemoglobin and the glucose clearance (K value). These results suggest that the measurement of glycosylated haemoglobin can be used as a simple and accurate index of glucose metabolism in islet transplanted rats.

Animals↗
PubMed1988

The organization of cervical screening in general practice.

Well organized cervical screening in general practice can have considerable clinical and financial rewards. Yet in a randomized survey of general practitioners in the United Kingdom only 43% operated a system for cervical screening which allows previously untested women to be identified and invited for testing.A younger age of general practitioner, a more rural practice, a larger practice size, employment of a practice nurse, a belief in the effectiveness of cervical screening and a positive view of the time spent on screening were all strong predictors of an organized approach to cervical screening within a practice. Being female or having a female partner was not statistically associated with systematic screening. The results demonstrate a need for education within general practice which emphasizes the relevance and significance of cervical screening and the essential contribution that can be made by each individual general practitioner to the success of the whole cervical screening programme.

Adult↗
PubMed1987

Transluminal angioplasty in the treatment of mesenteric vein graft stenosis.

We present 2 patients with chronic mesenteric ischemia who were successfully treated by mesenteric bypass grafts which then became stenosed and occluded. Patency was restored by percutaneous transluminal dilatation of the stenoses. Chronic mesenteric ischemia affects a population who are at high risk for surgical procedures, and second operations following occlusion of mesenteric grafts appear to carry an increased risk of both morbidity and mortality. We therefore suggest that transluminal angioplasty may prove a valuable form of treatment in these cases.

Angioplasty, Balloon↗
PubMed1987

Expression of Lassa virus nucleocapsid protein segments in bacteria: purification of high-level expression products and their application in antibody detection.

The Lassa virus nucleocapsid protein gene and segments from it were expressed in Escherichia coli under the control of the lac promoter in pUC-based plasmids. Expression of the near full-length protein [amino acid (aa) residues 12-570] fused to an N-terminal sequence of vector-derived 6 aa was not particularly efficient, and neither was that of a smaller N-terminal segment (aa 6-201) which was also fused at its C terminus to the remainder of the lacZ gene product. By contrast, the C-terminal 370 aa could be expressed at levels approaching 10% of total cellular protein. All the recombinant proteins were associated with the insoluble fraction after sonication of the bacteria. The inefficiently expressed products did not appear to be any more susceptible to proteolytic degradation. The distribution of codons rarely used in E. coli genes was relatively uniform along the nucleocapsid gene sequence. These results are consistent with the regulation of transcriptional or translational efficiency by features of the sequence downstream from the promoter and ribosome-binding site. The C-terminal segment (aa 201-570 representing 65% of the authentic protein) was purified by ion exchange chromatography and shown to be active when used as antigen in enzyme-linked immunoassays for virus-specific antibodies.

Antibodies, Viral↗
PubMed1987

Calculation of sample size in trials of screening for early diagnosis of disease.

The calculation of the sample sizes required for trials of screening for disease with the aim of reducing mortality involves the estimation of both the mortality in the control group at intervals after the start of the trial, and the potential reduction due to screening. Since at the start of a screening trial the population is selected to be free of the disease in question, the mortality rate in the control group will differ from that in the general population. A method of estimating this mortality rate using published incidence and survival data is described. The expected reduction in mortality due to screening depends both on the number of, and intervals between, screens and on parameters concerning the natural history of the disease; the means by which these parameters can be estimated are discussed. A trial of screening for colorectal cancer by a faecal occult blood test is used to illustrate these calculations.

Epidemiologic Methods↗
PubMed1987

Bovine serum albumin density gradient isolation of rat pancreatic islets.

The use of a bovine serum albumin (BSA) density gradient for isolation of rat pancreatic Islets of Langerhans after collagenase digestion has been compared with the standard Ficoll separation technique. The criteria studied were islet yield (insulin extraction of the islet interfaces and pellet), purity of preparation (amylase content of the islet preparation), insulin release characteristics, and the result of isologous transplantation in diabetic rats. The islet interface of the BSA gradient contained 62.2% of the total insulin, whereas the corresponding interface of the Ficoll gradient contained only 36.6% (P less than 0.001). The amylase content of the Ficoll-separated islet preparation was 6133 U/L, as opposed to 1230 U/L with BSA (P less than 0.001). BSA-isolated islets gave similar insulin release characteristics to non-density-gradient-isolated islets, whereas Ficoll-separated islets showed suboptimal insulin release. Single-donor-single-recipient transplantation was successfully performed with BSA-isolated islets whereas multiple donors were required with Ficoll-separated islets. Thus significantly improved results were found with the bovine serum albumin density gradient separation in all criteria and consequently the use of this gradient represents an advance in islet isolation techniques.

Animals↗
PubMed1986

Fecal occult blood screening for colorectal cancer in the general population. Results of a controlled trial.

A total of 26,975 asymptomatic individuals were identified from family doctors' age/sex registers and randomly allocated to test or control group. The first test group (10,253) were offered 3-day fecal occult blood (FOB) testing; 3,613 (37%) completed the tests and 77 (2.1%) were found to be positive. In this group, 13 cancers were detected (3.5/1000 persons screened), of which 9 (70%) were Stage A. Of these subjects, 3349 have been rescreened at 2 years; 2799 (85%) completed the tests and 80 (2.8%) were found to be positive. Four cancers have been detected (three Stage A). In the whole test group followed for 2 years (10,462), 34 cancers have presented (17 screening detected, 3 interval cases in test responders, 14 symptomatic cancers in nonresponders), of which 14 (43%) were Stage A. In the control group (10,272 individuals), 17 patients have presented with symptomatic colorectal cancer during the 2-year follow-up, with rates of 0.9/1000 and 0.8/1000 persons/year in the first and second years of follow-up, respectively. No Stage A tumors were present. In the second test group (3,225) offered both guaiac (Hemoccult; Smith Kline Diagnostics) and immunologic (Feca EIA; Nordic) FOB tests, 1304 (44%) completed the tests, of which 126 (9.7%) were positive. Five cancers were detected (four Stage A), of which only three were positive by Hemoccult testing. In this group of test responders, one cancer has presented symptomatically at 1 year follow-up. Thus, at 2-year follow-up of the responding individuals of both cohorts of the initial screen of the test group, 5 of 21 cancers (24%) were negative by Hemoccult testing. Fecal occult blood testing has doubled the detection of colorectal cancer in the test group compared with the number presenting with symptoms in 2 years in the control group, and increased the proportion of early stage cancers (chi 2 = 8.0, P = less than 0.001).

Aged↗
PubMed1986

The effect of Kupffer cell stimulation or depression on the development of liver metastases in the rat.

Tumour cells from a squamous carcinoma (approximately 2.5 X 10(5)) were injected intraportally into a syngeneic strain of rats to produce liver metastases 14 days later. Kupffer cells were stimulated by Corynebacterium parvum (7 mg or 1 mg i.v.) and zymosan (10 mg intraportally). Kupffer cell activity was depressed by the administration of silica, gadolinium chloride or human red cells. The animals in each group were sacrificed at 14 days, the livers removed and the number of visible surface metastases counted and compared. (Mann-Whitney U-test). Kupffer cell stimulation significantly reduced the number of surface liver metastases in all animals (P 0.0048). In contrast depression of Kupffer cell activity significantly increased the number of metastases in all animals (P 0.0045), suggesting that the activity of these cells has an important effect on the development of liver metastases.

Animals↗
PubMed1986

Influence of environment on GABA receptors in muricidal rats.

The influence of environment (isolation) on GABA receptor numbers ( [3H]-muscimol binding sites) and affinities was investigated in specific limbic areas known to be involved with the development of muricide. Olfactory bulbs of isolated rats were found to have identical numbers of [3H]-muscimol binding sites whether or not they were muricidal. However, in the olfactory bulbs of the aggregated animals a greater than two-fold increase was found in numbers of [3H]-muscimol binding sites in those rats that were muricidal. In the amygdala muricidal rats had a 32-34% increase in [3H]-muscimol binding sites over non-muricidal rats regardless of environment. In the septum non-muricidal rats had fewer [3H]-muscimol binding sites than muricidal rats and although the trend was evident, statistical vigor was seen only in the aggregated animals. Neither muricide nor isolation significantly influenced [3H]-muscimol binding numbers in the hypothalamus. GABA Ki values were examined in all brain regions and found to be the same in the isolated and aggregated animals whether or not they were muricidal. We concluded that environment appears to influence apparent GABA receptor numbers in the olfactory bulbs and septum whereas muricidal behavior correlates well with an increase in apparent number of GABA receptors in the amygdala. GABA receptors in the hypothalamus were not influenced by either environment or aggression.

Aggression↗
PubMed1986

Relationship of passive smoking to risk of lung cancer and other smoking-associated diseases.

In the latter part of a large hospital case-control study of the relationship of type of cigarette smoked to risk of various smoking-associated diseases, patients answered questions on the smoking habits of their first spouse and on the extent of passive smoke exposure at home, at work, during travel and during leisure. In an extension of this study an attempt was made to obtain smoking habit data directly from the spouses of all lifelong non-smoking lung cancer cases and of two lifelong non-smoking matched controls for each case. The attempt was made regardless of whether the patients had answered passive smoking questions in hospital or not. Amongst lifelong non-smokers, passive smoking was not associated with any significant increase in risk of lung cancer, chronic bronchitis, ischaemic heart disease or stroke in any analysis. Limitations of past studies on passive smoking are discussed and the need for further research underlined. From all the available evidence, it appears that any effect of passive smoke on risk of any of the major diseases that have been associated with active smoking is at most small, and may not exist at all.

Adult↗