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Biomedical subjects

H Peters

Publications and source records attributed to H Peters.

At least 127 records · Page 7Linked to original sources
PubMed1990

[What is the recurrence rate for Basedow's disease treated with thyrostatic agents. Answers from a prospective study].

Graves' disease is an autoimmune disease whose development involves immunogenetic and exogenous factors such as viruses, bacteria and iodine excess. In a number of patients the disease follows a chronic recurrent course. A recurrence rate of 50% can be expected one year after the end of therapy. Based on the preliminary results of the prospective study presented here, this recurrence rate does not differ in groups where patients underwent long-term treatment with 10 or 40 mg thiamazole. Retrospectively obtained data suggest that the time at which euthyroidism occurs under low-dose treatment is dependent on the alimentary iodine supply. A number of groups have attempted to develop clinically applicable methods to identify patients at risk for recurrence at the end of treatment. All the studies yielded controversial results. A prospective multicenter study was undertaken to reinvestigate the importance of measuring TSH receptor antibodies and performing the TRH test and the suppression test at the end of therapy in connection with this problem. In 451 patients the recurrence rate was 50.3% one year after the end of treatment. The patients in the recurrence group had a significantly higher rate of persistent antibody activity, no increase in TSH after TRH (negative TRH test), no normal suppressibility of thyroid 123 iodine uptake (negative suppression test) and larger goiter. The calculation of sensitivities and specificities shows, however, that these differences are not large enough to be of clinical importance for the individual patient.

Autoantibodies↗
PubMed1990

Thyroid peroxidase/microsomal antibodies are not identical with thyroid cytotoxic antibodies in autoimmune thyroiditis.

Cytotoxic activity in sera of patients with Hashimoto's thyroiditis was measured with an antibody-dependent cell-mediated cytotoxicity assay. Cytotoxicity was determined in a 51chromium release assay using human thyroid cell targets incubated with heat-inactivated serum or IgG from patients with Hashimoto's thyroiditis. Effector cells were obtained from peripheral mononuclear cells of normal subjects. Cytotoxicity was significantly increased in patients with Hashimoto's thyroiditis (median specific lysis 20.2%, range 2.1-58.8) compared with normals (median specific lysis 8.1%, range 0-19.5; p less than 0.00001). The amount of percent specific lysis did not correlate with the titres of microsomal antibodies determined by different methods: passive hemagglutination technique (r = 0.2), enzyme immunoassay with microsomal antigen (r = 0.16), and radioimmunoassay for thyroid peroxidase antibody (r = 0.02). The cytotoxic activity was located in the IgG fraction, both in microsomal antibody positive and negative sera. After pre-incubation of microsomal antibody/thyroid peroxidase antibody positive or negative sera with purified thyroid peroxidase followed by analysis in the antibody-dependent cell-mediated cytotoxicity assay, cytotoxicity decreased in only 2 cases but was unchanged in the remaining sera. Western blot experiments with solubilized thyroid membranes and immunoblotting with cytotoxic-positive/microsomal antibody negative sera showed no binding to thyroid peroxidase. Our data suggest that cytotoxicity in sera from patients with Hashimoto's thyroiditis is not mediated by antibodies against thyroid peroxidase, but by antibodies not yet identified.

Adult↗
PubMed1990

New ELISA test for detection of bovine leukemia virus infections in cattle, using bacterially synthesized p24.

A new ELISA test is described for the detection of antibodies to bovine leukemia virus protein p24. This test employs a bacterially synthesized p24 antigen which represents a hybrid protein consisting of beta-galactosidase and about 70% of the mature viral p24. The antigen preparation was enriched from Escherichia coli cells to 95% purity and was used for the detection of antibodies in cattle. In a selected set of 100 positive field sera, 97 could be verified by the new test.

Animals↗
PubMed1989

Perturbation of the sarcolemmal membrane in isoproterenol-induced myocardial injury of the rat. Permeability and freeze-fracture studies in vivo and in vitro.

The mechanism whereby cardiotoxic doses of isoproterenol (ISO) induces early permeability alteration of the sarcolemmal membrane is unknown; both beta-receptor overstimulation and direct toxic effect of ISO oxidation products have been implicated. There has been no morphologic observation, furthermore, on the structural basis of permeability alteration during this process. The purpose of the present study was to compare the morphology of cardiocyte injury induced by ISO and oxidized ISO (ISO-O2) and to visualize perturbation of the sarcolemma correlating with the leaky membrane. The authors studied the left ventricular myocardium of rats 10 and 60 minutes after subcutaneous administration of 85 mg/kg ISO and isolated perfused rat hearts exposed for 10 minutes either to ISO or ISO-O2 in a dose of 100 mg/l (10(-4) M) to determine the permeability of the sarcolemmal membrane using the extracellular diffusion tracer horseradish peroxidase (HRP) by light and thin section electron microscopy, the morphology of the sarcolemmal membrane by means of freeze-fracture electron microscopy, and the density of intramembrane particles (IMP) in the sarcolemmal membrane by planimetry using freeze-fracture electron microscopy. In in vivo rat hearts both 10 and 60 minutes after ISO and in vitro (isolated perfused) rat hearts exposed to either ISO or ISO-O2 for 10 minutes, HRP labeled the sarcoplasm of focally located cardiocytes implicating leakiness of the sarcolemmal membrane. HRP positive cardiocytes (with the exception of the in vivo 10 minute group) showed characteristic features of contraction band necrosis (both on light and thin-section electron microscopy) in all groups. Freeze-fracture electron microscopy of sarcolemmal protoplasmic (P) membrane faces revealed two populations of cardiocytes in all groups. P-membrane faces in one population of cardiocytes appeared as in the control. In the other population of cardiocytes, P-membrane faces showed irregular tears. Planimetry demonstrated a significant decrease of IMP numerical densities in P-membrane faces with tears in the in vivo 10 minute group and both with or without tears in the in vivo 60 minutes group and the in vitro groups compared with the control values. Furthermore, with the exception of the 10 minute in vivo group, IMP densities significantly decreased in sarcolemmal membranes with tears compared with those without tears in all experimental groups. These observations are consistent with the view that catecholamine induced myocardial injury is, at least partly, related to the direct toxic effect of catecholamine oxidation products on the sarcolemmal membrane.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1988

[The application of additives and compounds to meat products].

From the economic and perspective point of view the application of compounds and extenders in meat products represents an unavoidable world-wide development. The present study reviews additives and compounds for sausages and other comminuted meat products which have an influence on water binding and fat emulsifying. In the paper details and results of the patent publications published since 1960 are presented and discussed.

Animals↗
PubMed1988

Ketogenic effects of carnitine in patients with muscular dystrophy and cytochrome oxidase deficiency.

The effects of a single oral dose of carnitine on fasting-induced ketosis was investigated in four normal individuals, five patients with muscular dystrophy, and one patient with a generalized cytochrome c oxidase deficiency. Plasma carnitine, free fatty acids, glucose, insulin, and glucagon were also measured. Normal individuals showed an average 0.09 mM increase in blood beta-hydroxybutyrate concentration during a 12- to 18-hr period of fasting and carnitine administration did not affect this response (average: 0.12 mM). Muscular dystrophy patients showed a greater fasting-induced elevation in beta-hydroxybutyrate (average 0.29 mM) and carnitine administration greatly enhanced this ketogenic response (average 0.84 mM). The cytochrome c oxidase deficient patient showed an even larger increase in beta-hydroxybutyrate with fasting (1.67 mM) and carnitine further augmented this ketotic effect (3.78 mM). Plasma free fatty acids were also elevated in patients that showed enhanced ketosis. Plasma glucagon concentration did not change, but insulin levels decreased during the 12- to 18-hr period of fasting; no major differences were found between controls and patients. These results indicate that some patients with muscular dystrophy and cytochrome c oxidase deficiency are more prone to develop ketosis than normal individuals and that carnitine administration enhances this response. Since both muscular dystrophy patients and the patient with cytochrome c oxidase deficiency had similar ketogenic responses, the data suggest that ketone body utilization may be impaired in these patients. The ability of L-carnitine to be ketogenic should be considered in the treatment of these patients.

Adult↗
PubMed1988

[Ultrasound imaging of the bile ducts and assessment of gallbladder kinetics in healthy newborn infants].

The gallbladder and the biliary tract of 85 neonates were sonographically examined, in the fasting state. The gallbladder was detectable in all neonates and showed a measurable contraction. Two types of biliary contraction could be observed: a concentric contraction of length, depth and width (concentric type) or a contraction of depth and width (collapse type). The grade of postprandial contraction was independent of the level of serum bilirubin. Furthermore, sonographic criteria were established allowing the differentiation of the bile ducts and their discrimination from hepatic arteries.

Bile Ducts↗
PubMed1988

Nutrient supplement use by healthy elderly.

As part of a nutritional status survey of 691 non-institutionalized men and women aged 60 years and older, supplement use was reported by 45% of the males and 55% of the females. Supplement use was more prevalent in females than males at each age decade. Vitamins C and E were the most commonly used supplements. Mean dietary nutrient intakes were calculated from a 3-day food diary. The percentage of dietary intakes falling below 2/3 1980 Recommended Dietary Allowance (RDA) was comparable for users and non-users of supplements. Use of supplements markedly decreased the proportion of subjects with inadequate nutrient intake (using a 2/3 RDA criterion), particularly for vitamins B6, B12, and D, folic acid, and calcium. However, for both males and females, potentially excessive intake levels (10 times the RDA) of thiamin, vitamin A, and vitamin E supplementation were observed.

Aged↗
PubMed1988

Dietary intakes and biochemical indicators of nutritional status in an elderly, institutionalized population.

A dietary and biochemical assessment of the nutritional status of 260 elderly men and women, 60-101 y (average 80.5 y), was conducted in 15 long-term-care facilities in the Boston area. Subjects were free of clinically apparent terminal or wasting illness. Nutrient intakes were comparable to those in a simultaneously studied free-living population as were most biochemical markers of nutrient status. Although no specific nutrient deficiencies were identified, blood levels of vitamin A and retinol-binding protein in males and of zinc in both sexes were lower in this institutionalized group than in the free-living subjects. Hematologic indices, albumin, prealbumin, and transferrin levels were also lower than in noninstitutionalized elderly populations. These differences may reflect the greater prevalence of chronic diseases and medication use in a long-term-care population. However, there is no evidence that institutionalization in itself leads to impairment of nutritional status.

Aged↗
PubMed1988

[Clinical picture and course of children with CHARGE association].

Four children are described who presented malformations according to CHARGE-Association. The primary abnormalities were choanal atresia and/or Coloboma. All four cases exhibited esophageal malformations: atresia and/or fistulas. At autopsy, three children showed arhinencephaly which is rarely observed in patients with CHARGE-Association. Patients with the main features of CHARGE-Association have a very poor prognosis depending on the severity of the malformations.

Abnormalities, Multiple↗
PubMed1987

[Proton spin tomography in childhood. Experience with 407 studies in 275 children and adolescents].

Over a period of three years magnetic resonance imaging (MRI), mostly neuroradiological, was performed 407 times in 275 children. It was found that MRI largely replaced previously applied imaging methods for solving oncological and neurological problems. The sensitivity of the method is poor for demonstrating small calcifications (computed tomography is better), for diffuse meningeal lesions (lumbar puncture is better), and diffuse spinal-canal metastases (myelography is better). The great advantage of the method lies in its low x-ray exposure because of the low field strength, and it can therefore be safely used repeatedly.

Adolescent↗
PubMed1987

Thermoregulation during prolonged exercise in heat: alterations with beta-adrenergic blockade.

Thermoregulation and cardiovascular drift were studied under conditions of prolonged exercise in a warm environment (dry bulb temperature 31.7 +/- 0.3 degrees C, rh 44.7 +/- 4.7%) during beta-adrenergic blockade. Fourteen subjects performed 90-min rides on a cycle ergometer at a work rate equivalent to 40% of their control maximal O2 uptake under each of three treatments provided in a randomized double-blind manner: atenolol (100 mg/day), propranolol (160 mg/day), and a placebo. Exercise during the propranolol trial resulted in significantly higher forearm vascular resistance values and significantly lower forearm blood flows (FBF) compared with the placebo trial. However, the significantly lower FBF during propranolol did not significantly alter the rectal temperature (Tre) response to prolonged exercise. In addition, both beta-blockers produced lower FBF for any given Tre, suggesting that beta-adrenergic blockade affects FBF through nonthermal factors. The slight differences in Tre, despite the large differences in FBF between the various treatments, are apparently the result of an enhanced sweat loss and a lower mean skin temperature during exercise with beta-blockade. The uncoupling of FBF and sweat loss provides evidence of independent regulation. The reduction in FBF at any given Tre was concomitant to lower blood pressure values during beta-blockade and suggests that baroreflexes provide significant input to the control of skin blood flow when both pressure and temperature maintenance are simultaneously challenged.

Adult↗
PubMed1987

Intermittent negative pressure ventilation in the treatment of respiratory failure in progressive neuromuscular disease.

Five men with degenerative neuromuscular diseases (three with amyotrophic lateral sclerosis [ALS] and two with Duchenne's muscular dystrophy [DMD]) who had respiratory failure were treated with intermittent negative pressure ventilation (NPV). One patient with ALS in severe acute respiratory failure was successfully treated with NPV alone. This patient and two other ALS patients in chronic respiratory failure with PaCO2 elevation stabilized or improved their vital capacity (VC) and lowered their PaCO2 after 5 to 11 weeks of therapy. Finally, intermittent NPV was used to replace 24-hour positive pressure ventilation in two patients with DMD. It is concluded that intermittent NPV may stabilize or temporarily improve the respiratory status in patients with progressive neuromuscular diseases.

Adult↗
PubMed1986

Real-time ultrasound in Crohn's disease: characteristic features and clinical implications.

Thirty-two children with Crohn's disease were evaluated by real-time ultrasonography. The typical pattern of Crohn's disease caused by bowel wall thickening is the "bull's eye phenomenon", the elongated tubular stiff bowel loop with narrowing of the lumen and the small bowel conglomerate tumor. In indefinable abdominal complaints sonography may lead to the correct diagnosis. The differential diagnosis of similar sonographic features and the limitations of ultrasound in gastrointestinal disease must be considered. In proven Crohn's disease the findings in follow-up match the clinical course and may delineate complications, such as ileus, abscess, hydronephrosis, gallstones or involvement of parenchymal organs, as seen in 15 patients. Thus ultrasound will restrict repeated x-ray studies and support patient management.

Adolescent↗