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Biomedical subjects

C Sampson

Publications and source records attributed to C Sampson.

At least 37 records · Page 2Linked to original sources
PubMed1992

Immunoprophylactic trial with combined Mycobacterium leprae/BCG vaccine against leprosy: preliminary results.

In an attempt to find a vaccine that gives greater and more consistent protection against leprosy than BCG vaccine, we compared BCG with and without killed Mycobacterium leprae in Venezuela. Close contacts of prevalent leprosy cases were selected as the trial population since they are at greatest risk of leprosy. Since 1983, 29,113 contacts have been randomly allocated vaccination with BCG alone or BCG plus 6 x 10(8) irradiated, autoclaved M leprae purified from the tissues of infected armadillos. We excluded contacts with signs of leprosy at screening and a proportion of those whose skin-test responses to M leprae soluble antigen (MLSA) were 10 mm or more (positive reactions). By July, 1991, 59 postvaccination cases of leprosy had been confirmed in 150,026 person-years of follow-up through annual clinical examinations of the trial population (31 BCG, 28 BCG/M leprae). In the subgroup for which we thought an effect of vaccination was most likely (onset more than a year after vaccination, negative MLSA skin-test response before vaccination), leprosy developed in 11 BCG recipients and 9 BCG/M leprae recipients; there were 18% fewer cases (upper 95% confidence limit [CL] 70%) in the BCG/M leprae than in the BCG alone group. For all cases with onset more than a year after vaccination irrespective of MLSA reaction the relative efficacy was 0% (upper 95% CL 54%; 15 cases in each vaccine group). Retrospective analysis of data on the number of BCG scars found on each contact screened suggested that BCG alone confers substantial protection against leprosy (vaccine efficacy 56%, 95% CL 27-74%) and there was a suggestion that several doses of BCG offered additional protection. There is no evidence in the first 5 years of follow-up of this trial that BCG plus M leprae offers substantially better protection against leprosy than does BCG alone, but the confidence interval on the relative efficacy estimate is wide.

BCG Vaccine↗
PubMed1992

The prevalence of enlarged mediastinal lymph nodes in asbestos-exposed individuals: a CT study.

Patients with cryptogenic fibrosing alveolitis have a higher prevalence of enlarged mediastinal lymph nodes compared with the normal population. To determine whether or not this observation applies to individuals with asbestos-induced pulmonary fibrosis the high resolution computed tomography (CT) scans of 14 patients with definite asbestosis and 11 age-matched cases with benign asbestos-induced pleural disease, but no lung disease, were re-imaged on soft tissue settings. The site, size and number of mediastinal lymph nodes equal to, or greater than, 1.2 cm were recorded. In the asbestosis group 14 out of 14 patients had at least one enlarged lymph node with an average number per individual of four (range 1-10). In the control group two out of 11 patients each had one minimally enlarged lymph node. We conclude that mediastinal lymph node enlargement occurs frequently in asbestosis: awareness of this is important in the investigation of malignant disease in patients with asbestosis.

Aged↗
PubMed1992

Heparin, fatty acids and sodium, potassium-ATPase inhibition by plasma factors during hemodialysis.

To assess the relationship between heparin and the associated increase in nonesterified fatty acids (NEFA) and their possible influence on Na,K-ATPase during hemodialysis, we studied two groups of patients: (1) 12 patients on chronic hemodialysis dialysed with heparin and (2) 6 patients dialysed without heparin. All 12 patients who received heparin anticoagulation had a 7-fold rise in NEFA on average and also had an increase in circulating inhibitors of Na,K-ATPase assayed by 3H-ouabain displacement from Na,K-ATPase and/or by effect of plasma on the uptake of 86Rb by rat aortic rings. Serial assays in 3 of the patients receiving heparin showed NEFA and inhibitory changes to be at or near maximum within 30-60 min. Of the individual NEFA, the greatest relative increases were in oleic (18:1) and linoleic (18:2) acids, and the strongest correlations were between linoleic acid and both 3H-ouabain displacement (r = 0.94) and 86Rb uptake (r = 0.86). However, a small and slower increase in NEFA also occurred in 3 of the patients dialysed without heparin. We conclude that heparin anticoagulation during dialysis leads to a rapid and marked increase in circulating NEFA, particularly the unsaturated fatty acids, with a corresponding interference with Na,K-ATPase activity. The clinical significance of these findings is unknown. The rise in NEFA during dialysis without heparin in some patients suggests that factors other than heparin may also contribute to the rise in NEFA.

Adult↗
PubMed1991

Magnetic resonance morphological, chemical shift and flow imaging in peripheral vascular disease.

We have used magnetic resonance imaging to study the aorto-iliac region in 13 patients with peripheral disease. Five healthy volunteers were studied for comparison. Magnetic resonance spin-echo imaging, chemical shift imaging to determine lipid content of atheroma, phase-shift velocity mapping and quantitative flow studies were obtained and the findings compared with radiological angiograms. The velocity profiles study showed an increased velocity at the site of a stenosis in eight patients who had iliac artery disease. Quantitative flow measurements made in both iliac arteries and the aorta in five patients and five volunteers showed a flow ratio in both iliac arteries less than 0.85 in patients with a stenosis of one iliac artery and a ratio greater than 0.85 in the volunteers. In one patient studied before and after angioplasty, flow improved post-angioplasty. The flow curve showed a characteristic distortion in diseased vessels compared with healthy vessels. In the chemical shift images of aortic atheroma five were classified as fibrous and three were lipid rich. This preliminary study showed the potential of magnetic resonance to assess non-invasively the morphology, composition and the haemodynamic significance of atheroma. This could be important in the study of the progression of peripheral vascular disease and its response to pharmacological and surgical intervention and in the planning treatment of lesions.

Adult↗
PubMed1991

IgM antibodies to native phenolic glycolipid-I in contacts of leprosy patients in Venezuela: epidemiological observations and a prospective study of the risk of leprosy.

In a randomized, double-blind vaccine trial in Venezuela, about 29,000 contacts of leprosy patients have been vaccinated with either a mixture of heat-killed Mycobacterium leprae and BCG or BCG alone, and are being re-surveyed annually to detect new cases of leprosy. All contacts had a serum sample collected at the time of entry into the trial, and 13,020 of these sera have been analyzed for antibodies to phenolic glycolipid-I (PGL-I). Antibody levels have been related to various characteristics of the contacts and to their risk of developing leprosy in the following 4 years. A strong association was found between PGL-I antibody level and the risk of developing leprosy, in spite of possible modification of the incidence rate induced by vaccination. Antibody levels were higher in females than in males, and declined progressively with age. Household contacts had higher levels than did non-household contacts, and levels were higher in individuals from the state in Venezuela which has the highest incidence of the disease. No substantial differences were found in antibody levels between contacts of multibacillary and paucibacillary patients, which may in part reflect the influence of treatment, and there was no clear association with the presence of BCG or lepromin scars or with skin-test responses to PPD and leprosy soluble antigen. The assay of antibodies to PGL-I seems unlikely to provide a sensitive or specific test for infection with M. leprae, and measuring PGL-I antibody levels as a screening procedure to identify those at high risk of developing leprosy is unlikely to be particularly useful in most leprosy control programs. Such assays may be useful for the epidemiological monitoring of changes in the intensity of infection with M. leprae in a community and for the study of carefully defined groups of contacts during some phases of control programs.

Adolescent↗
PubMed1988

Pentavalent [99mTc]DMSA, [131I]MIBG, and [99mTc]MDP--an evaluation of three imaging techniques in patients with medullary carcinoma of the thyroid.

Nine patients with histologically proven medullary carcinoma of the thyroid (MCT) were imaged using pentavalent [99mTc]dimercaptosuccinic acid [(V)DMSA], [131I] metaiodobenzylguanidine (MIBG) and [99mTc]methylene diphosphonate (MDP). Technetium-99m (V)DMSA demonstrated most of the tumor sites in eight patients with proven metastases, with an overall sensitivity of 95% in lesion detection. Iodine-131 MIBG showed definite uptake in some of the tumor sites in three of the nine patients imaged, with equivocal uptake seen in a further one patient, with sensitivity of only 11% for lesion detection. Technetium-99m MDP demonstrated bony metastases only, in four of the patients imaged yielding a sensitivity of 61%. Technetium-99m (V)DMSA has been demonstrated in this study to be a useful imaging agent in patients with MCT, showing uptake in significantly more lesions and with better imaging qualities than [131I]MIBG, and with the ability to detect soft tissue as well as bony metastases.

3-Iodobenzylguanidine↗
PubMed1988

The role of vascular Na,K-ATPase activity in salt induced hypertension in Dahl rats.

The role of endogenous inhibitors of vascular Na,K-ATPase (NKA) activity in salt-induced hypertension was evaluated by examining the inhibition of 86Rb+ uptake in aortae of Sprague-Dawley (SD) rats by plasma derived from Dahl sensitive (DS) and resistant (DR) rats given high (8%) and low (0.4%) NaCl diet for four weeks. With 4 weeks of high salt diet DS rats demonstrated marked increase in systolic blood pressure. When compared to DR and DS rats on low salt diet, plasma from DR and DS rats on high salt diet had a stimulatory (not inhibitory) effect on NKA as measured by 86Rb+ uptake of SD rat aortae. As compared to DR rats plasma from DS rats on similar salt intakes had a stimulatory effect on NKA of SD rats. Aortae from the 4 groups of Dahl rats were also assayed for NKA activity. Total, ouabain-sensitive and ouabain-insensitive NKA activities were higher in DS rats as compared to DR rats on similar salt diet. Both DS and DR rats on high salt diet had higher NKA activity than on low salt diet. There was no evidence for a decrease in vascular sodium pump activity accompanying hypertension. Furthermore, high salt diet did not increase plasma Na,K-ATPase inhibitory activity in DS rats when hypertensive. These results suggest that NKA inhibition plays a minor role if any in hypertension of DS rats, in contrast to what has been hitherto believed.

Animals↗
PubMed1984

Spontaneous renal allograft rupture 4 years after transplantation.

Previously, the longest reported interval between clinical renal transplantation and 'spontaneous' renal allograft rupture was 170 days. We here report a case with an interval of 4 years between renal transplantation and the delayed 'spontaneous' renal allograft rupture (DSR). The aetiology appears to be a vigorous rejection confirmed by operative and pathological findings. The patient who was a cadaver donor recipient presented with pain and tenderness at the transplant site, falling haematocrit, hypotension and azotaemia. The details of this presentation are discussed and the need for immediate transplant nephrectomy is emphasized.

Graft Rejection↗
PubMed1978

Sickle cell anemia and transposition of the great vessels.

A child with homozygous sickle cell disease and transposition of the great vessels had erythrocytosis associated with markedly increased plasma erythropoietin activity. Her clinical course was complicated by neurologic manifestations but not by recurrent sickle cell vasooculsive episodes. The fetal hemoglobin level which had been greater than 25% during the first two years of life gradually decreased to less than 10%. She died at 3 years of age of congestive heart failure and severe anemia. The only sickle cell painful crisis occurred during her terminal illness. It is likely that the high levels of fetal hemorglobin decreased sickling and thus allowed erythrocytosis to develop. Fetal hemoglobin may also have prevented frequent vaso-occlusive events despite the high hematocrit level.

Anemia, Sickle Cell↗
PubMed1977

Royal College of Nursing (Rcn) code of professional conduct: a discussion document.

We are printing in its entirety the discussion document which sets out a code of professional conduct for nurses published by the Royal College of Nursing in November 1976 together with commentaries by the Assistant Secretary of the British Medical Association, a professor of nursing studies, student nurses and a lawyer. The image of the nurse is still that of one of Florence Nightingale's young ladies or of a member of a religious order who is wholly dedicated to caring for the sick. Today, as this document and the comments upon it show, 'dedication' is still part of the motive which leads a man or woman to become a nurse but in addition, and this is where the public may be ignorant or choose to be ignorant, nursing offers a career where intellectual achievement and the satisfaction of a demanding job bring their proper financial reward and place in the professional community. We are grateful to the Royal College of Nursing for permission to publish this document.

Codes of Ethics↗
PubMed1976

Spontaneous renal allograft rupture without rejection: a case report.

A case of spontaneous renal allograft rupture is described. Typically, this infrequent transplant complication occurred in the early post-transplant period in an oliguric setting with progressive pain, tenderness and swelling at the transplant site associated with hypotension and a decreasing hematocrit. Prompt surgical exploration and repair of the defect in the convex border of the renal allograft controlled hemorrhage and resulted in graft survival, and a normal blood urea nitrogen and creatinine 10 months after transplantation. There have been no rejection episodes and the renal biopsy demonstrated no evidence of rejection or acute tubular necrosis. Ice preservation for 24 hours and changes secondary thereto may have made the kidney susceptible to rupture when the position of acute flexion was assumed.

Adult↗
PubMedDate not supplied

Pharmacokinetics of tinidazole in male and female subjects.

Tinidazole is a potent nitroimidazole compound active against, and used to treat, Trichomonas vaginalis infections in males and females. Speculation exists in the literature that observed differences in tinidazole plasma concentrations between males and females may be due to sex-mediated pharmacokinetic differences. To investigate this phenomenon, a study was designed to determine the pharmacokinetics of tinidazole in male and female subjects. Six male and six female volunteers were each administered a single 2-Gm oral dose of tinidazole. Plasma and urine samples, collected over a 72-hour period, were assayed by a sensitive and specific HPLC assay. Results demonstrate a significant correlation between tinidazole oral plasma clearance and body weight and apparent volume of distribution of tinidazole and body weight for male and female subjects, respectively. There were no apparent sex-mediated differences in weight-normalized pharmacokinetic parameters as documented by statistically equivalent mean oral plasma clearances (36.1 and 35.4 ml/kg/hour), apparent volumes of distribution (0.65 and 0.63 liter/kg), and elimination half-lives (12.3 and 12.3 hours, males and females, respectively). Mean area under the tinidazole plasma concentration-versus-time curve and mean peak plasma concentration of tinidazole were 1.3 times greater for females than for males, apparently due to the smaller mean body weight of females and consequently a 1.3 times greater administered dose to the females on a weight basis.

Adult↗
PubMedDate not supplied

Saphenous vein graft pseudoaneurysm: diagnosis by transesophageal echocardiography and magnetic resonance imaging.

Coronary cineangiography showed probable pseudoaneurysm formation at the origin of an 11-year-old saphenous vein coronary bypass graft. Transesophageal echocardiography and magnetic resonance imaging were helpful in differentiating this from aortic dissection or true aneurysm formation and assisted the surgeon in avoiding perforation of the pseudoaneurysm during sternotomy.

Aneurysm, False↗