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Biomedical subjects

H Walter

Publications and source records attributed to H Walter.

At least 163 records · Page 9Linked to original sources
PubMed1989

Implantation of programmable infusion pumps for insulin delivery in type I diabetic patients.

Five type I diabetic patients were followed prospectively during treatment with continuous subcutaneous insulin infusion by externally worn pumps and during the first 12 months after implantation of a remote-controlled insulin infusion device (ID1, Siemens AG). Stabilized insulin (Hoe 21 GH, Hoechst AG) was infused intravenously in two and intraperitoneally in three patients. Total observation time was 47.2 patient-months after implantation. Two devices had to be explanted prematurely, one because of a technical failure after 101 days, one due to a skin necrosis over the implant after 236 days. HbA1, frequency of hypoglycemia, total insulin dose, and basal rate infusion did not change after implantation. There was a reduction in the insulin antibodies 6 months after start of intravenous or intraperitoneal insulin delivery. Fasting plasma free insulin levels could be normalized only by intraperitoneal insulin infusion. Although a technical and a surgical problem was observed, our data show the successful implantation and clinical use of programmable dosing devices and stabilized insulin.

Adult↗
PubMed1989

[Diabetic ketoacidosis during insulin pump therapy].

During treatment of four type-1 diabetics (aged 20-46 years) by continuous subcutaneous insulin infusion (CSII) a leak developed in the system which caused severe ketoacidosis. The gastrointestinal symptoms (nausea, vomiting and abdominal pain) were misdiagnosed by both the patients and their doctors because there was only mild hyperglycaemia. These observations highlight the importance of carefully instructing and supervising patients at the beginning of CSII and point to the need of frequent urine testing by the patients, also for urinary keto bodies.

Adult↗
PubMed1989

[Treatment of diabetes with insulin pumps. Current status and insurance medicine aspects].

The continuous subcutaneous insulin infusion (CSII) by means of portable dosing devices ("insulin pumps") represents a new therapeutical principle in the treatment of type I diabetics. Developed in 1978/79, subcutaneous infusion is being used increasingly in today's routine therapy. It achieves an almost physiological distribution of insulin between a basal rate (basic insulin requirement) and additional rates (insulin requirement depending on food-intake), leading to an improvement not only in metabolism but also in the quality of patient's life (increased flexibility in everyday life). The prerequisites for successful therapy are stated and therapy-specific complications are analysed on the basis of the experience of the III. Medical Department of the City Hospital Munich-Schwabing with 104 patients over an accumulated period of 283 treatment years. An outline is given of future advancements in the field of controlled insulin dosage with the help of infusion systems. Important aspects of insurance medicine are pointed out, such as the registration of substandard risks by means of a questionnaire especially developed for that purpose and the prognostic evaluation as compared to forms of therapy applied so far. The reasons for the current classification of this new therapeutical method as prognostic/experimental are indicated and the procedure for selecting favourable risks is described.

Diabetes Mellitus, Type 1↗
PubMed1989

Fixation with even small quantities of glutaraldehyde affects red blood cell surface properties in a cell- and species-dependent manner. Studies by cell partitioning.

Partitioning in charge-sensitive dextran-poly(ethylene glycol) aqueous phase systems reveals that fixation with even small concentrations of glutaraldehyde (e.g., 0.1% w/v) changes the surface properties of cells. While fixation with larger concentrations of glutaraldehyde (i.e., 1.85%) increases erythrocyte partition ratios, the effect of lower glutaraldehyde concentrations on the partition ratios appears to be species-specific. The differential effect of glutaraldehyde on rat reticulocytes and erythrocytes indicates that fixation is also cell-dependent. These data, together with the previous report that glutaraldehyde fixation does not change the characteristic relative partition ratios of rat mature erythrocytes of different cell ages, suggest that the nature and extent of glutaraldehyde alteration of cell surfaces must, in each case, be empirically evaluated.

Aldehydes↗
PubMed1989

Thromboxane-mediated hypertension and vascular leakage evoked by low doses of Escherichia coli hemolysin in rabbit lungs.

Escherichia coli hemolysin has been implicated as a pathogenicity factor in extraintestinal E. coli infections including sepsis. In the present study the effects of intravascular administration of hemolysin were investigated in isolated blood-free perfused rabbit lungs. Low concentrations of the toxin in the perfusate (0.05-5 hemolytic units/ml, corresponding to approximately 5-500 ng/ml), caused a dose- and time-dependent release of potassium, thromboxane A2, and prostaglandin I2, but not of lactate dehydrogenase, into the recirculating medium, as well as a dose-dependent liberation of the prostanoids into the bronchoalveolar space. These events were paralleled by a dose-dependent pulmonary hypertension, and studies with different inhibitors collectively indicated that the vasoconstrictor response was mediated predominantly by pulmonary thromboxane generation. In addition, E. coli hemolysin elicited a protracted, dose-dependent increase in the lung capillary filtration coefficient, which was independent of the prostanoid-mediated pressor response and resulted in severe pulmonary edema formation. We conclude that E. coli hemolysin can elicit thromboxane-mediated pulmonary hypertension combined with severe vascular leakage in isolated lungs in the absence of circulating inflammatory cells and humoral mediator systems, mimicking the key events in the development of acute respiratory failure in states of septicemia.

Animals↗
PubMed1989

Genetic studies in four populations of the northern Aegean Sea, Greece.

A total of 945 non-related individuals from four isolated population groups from the Northern Aegean Sea (Greece)--Alonissos, Oxilithos, Skopelos, and Glossa, has been typed for 16 polymorphic systems of the blood, namely A1A2B0, MNS., Rhesus (C, c, Cw, D, E, e), Kell, Duffy (a,b), Kidd (a); Hp, Tf subtypes, Gc, Gm (1, 2, 3, 5, 13), Km (1); aP, AK, PGM1, EsD, and 6-PGD. The distribution of phenotype and gene/haplotype frequencies shows a considerable interpopulational variability, which is discussed considering the history of these populations as well as the impact of locally acting microevolutionary factors such as drift and founder effects. The average coefficient of gene diversity GST comes to 0.0147, whereas Wahlund's variance is on average 0.0154, and Wright's Fst = 0.0147. Genetic distance analysis reveals a pattern of similarities, which is in conformity with the history of the populations under study.

Blood Group Antigens↗
PubMed1989

Insulin delivery by implanted pumps: one-year trial with programmable infusion systems (the Point Study).

A feasibility trial was carried out in four European centers to test the safety and efficacy of stabilized insulin (HOE 21GH) in twenty remote-controlled infusion pumps (Siemens AG) implanted in twenty type I diabetic patients. Fifteen had been implanted with intraperitoneal and five with the intravenous access route. Total observation time was 18.2 patient years. A total of 36,077 self blood glucose measurements were collected from the patients. Of these 62.9% were in the acceptable range of 70-160 mg/dl. Symptomatic hypoglycemias were rare and reported in a frequency of 2.6 per patient months; of these 0.22 per patient year required medical attention. The median of HbA1c was in the upper normal range or slightly above. Three pumps had to be explanted prematurely because of surgical and technical problems. Although some technical and clinical problems were still observed, the study shows the successful clinical use of implanted, remote-controlled dosing devices and the special insulin preparation stabilized with polyethylene-polypropylene-glycol.

Adult↗
PubMed1989

Medication and drug abuse in relation to road traffic safety.

Apart from alcohol, various other substances with a psychotropic effect have been discussed recently in relation to their association with road traffic safety. There has been a general lack of hard facts, however, on how much drug use and abuse influence this. In the absence of data on the frequency of such effects, a representative random sample (approx. 8000 persons) of the Austrian population was interviewed and questioned on their drug intake. A smaller sample (2007 persons) was also questioned as to their behaviour regarding road traffic participation. The results showed that those drugs taken most frequently belong to the 'analgesic' group, whilst the frequency in use of substances to which greater importance is attached currently regarding road safety is relatively low (tranquillizers by 4%; strictly 'psychotropic' drugs by 0.3% to 0.6% of the population). These findings are similar to those reported in English-speaking countries. Data analysis showed that socio-cultural factors (age, sex, marital status and profession) influence the frequency and type of drug intake. The definition of drug abuse and addiction used (increase of dosage, inappropriate use, effect changes) proved somewhat unreliable and called into question the criteria used for diagnosis and categorization of persons at risk. In view of the results of previous studies and the importance attached by critics, an unexpected finding of this survey was the minor influence exerted by tranquillizers on road traffic safety. However, the number of cases for individual drug classes was relatively small and there is a need for more broadly based studies of a similar design before reaching firm conclusions.

Accidents, Traffic↗
PubMed1989

Genetic heterogeneity and population structure in eastern India: red cell enzyme variability in ten Assamese populations.

This paper is a part of the genetic study of the people of Assam (eastern India), initiated by the Anthropometry and Human Genetics Unit, Indian Statistical Institute, Calcutta, India, and the Dept. of Human Biology/Physical Anthropology, University of Bremen, W. Germany. The results of 1. allele distribution of five red cell enzyme polymorphisms in ten Assamese populations, 2. heterogeneity of allele frequencies and extent of gene differentiation among these populations, and 3. standard genetic distances are presented here. A total of 1024 blood samples was screened for aP, E D, AK, ADA and LDH enzyme systems for Brahmins, Kalitas, Kaibartas, Rajbanshis, Muslims, Ahoms, Chutiyas, Kacharis, Karbis (Mikirs) and Sonowals, of which the latter three are tribes. The gene diversity (FST) is smallest (0.0035) for pa and highest (0.1604) for HbE. The total FST value (0.0399 +/- 0.0141) appears to be statistically significant. From distance analysis two major clusters with sub-clusters in each are visible, which are in conformity with the ethnohistory of these populations.

Asian People↗
PubMed1989

Anthropological studies in Assam, India. 7. Socio-biological observations on Assamese populations.

Three population groups of Assam, viz., the Hindus, Muslims and Mongoloids have been investigated for certain bio-social variables, e.g., size and composition of family, sex distribution, menarcheal age, age at marriage, marriage distance, conception, pregnancy wastage and fertility. The results are discussed on comparative basis, and attempts are made to offer possible reasons for differences.

Adolescent↗
PubMed1989

Genetic studies in a Hungarian isolate: Ivád.

A total of 675 individuals from the Hungarian isolate Ivád has been typed for 25 genetic polymorphisms. This sample was devided into three subgroups: 1. Full Ivádys (both spouses and their ancestors are members of the Ivád family; n = 330), 2. Half Ivádys (= either husband or wife and his or her, respectively, ancestors are from the Ivády family, the other partner from the outside population; n = 267), and 3. Non-Ivádys (married couples not belonging to the Ivády family; n = 78). The main concern of this paper is 1. to show to intra-Ivád variability of the distribution of various genetic parameters (allele frequencies, heterozygosity, gene diversity etc.) among these three groups, and 2. to analyze the impact of the different mating patterns of these groups on the genetic structure of the Ivád population. From the comparison of the Ivád gene frequencies with that of neighbouring populations (Pétervására and Erdökövesd) it is seen that drift or founder effects played some role. Within the Ivád population only few gene frequencies show a marked heterogeneity. As expected the average heterozygosity in Full Ivádys is somewhat lower than in Half Ivádys and Non-Ivádys, respectively. The pattern of genetic relationships of the various Ivád groups is in conformity with the demographic and historical facts of this village.

Alleles↗
PubMed1988

Effect of rapidity of phase separation on the efficiency of cell fractionation by partitioning in aqueous two-phase systems.

Partitioning in two-polymer aqueous phase systems is an established method for the separation, purification and characterization of biomaterials. Because of the relatively slow settling rates of these phases, a consequence of the slight difference in density between them, effort has been directed to speeding up phase separation by various means (e.g., the development of a thin-layer countercurrent distribution apparatus). This has resulted in the more rapid processing of materials. Unlike soluble materials, biological particulates (e.g., cells) generally partition between one of the bulk phases and the interface. The mechanism of cell partitioning involves cell-specific adsorption to droplets of one phase suspended in the other, subsequent to phase mixing, and the delivery of adsorbed cells to the bulk interface as the droplets settle. In this communication we show, using erythrocytes as a model, that speeding up phase separation is counterproductive when partitioning cells and results in reduced efficiency of their separation or subfractionation. The most likely reason for this result is that increasing the speed of phase settling removes the droplets of one phase suspended in the other more rapidly than cells can attach to them, thereby interfering with the mechanism whereby cells partition.

Animals↗
PubMed1988

Partitioning behavior of erythrocytes in aqueous two-phase systems containing hydroxypropyl starch and polyethylene glycol.

The partitioning behavior of erythrocytes in Reppal PES 200 (a hydroxypropyl starch produced by Reppe Glykos AB, Växjö, Sweden)-polyethylene glycol (PEG) and in dextran (Dx)-PEG aqueous phase systems made isotonic with phosphate is similar in a number of ways: (i) There is a correlation between the relative electrophoretic mobilities and partition ratios, P, of red blood cells from different species; (ii) The cell P is reduced when, at constant polymer concentrations, phosphate is systematically replaced by sodium chloride (with the total concentration isotonic); (iii) The cell P is increased with reduced polymer concentrations (decreased interfacial tensions); (iv) Treatment of erythrocytes with neuraminidase results in a reduced P value; (v) Rat red cells of different ages can be fractionated by counter-current distribution; and (vi) Differences between red blood cells from genetically distinct rats or between humans can be detected. Aquaphase (a hydroxypropyl starch marketed by Perstorp AB, Lund, Sweden) has been tested as in ii-iv above with analogous results. The partitioning behavior of erythrocytes in PES-PEG and Dx-PEG aqueous phase systems containing sodium chloride differs in a number of ways: (vii) The correlation, apparent in Dx-PEG systems, between the P value of red blood cells from different species and the ratio of their membrane poly- to monounsaturated fatty acids is absent in PES-PEG systems. It is replaced by a correlation as in i; (viii) The increase in P value in Dx-PEG observed from red blood cells after treatment with neuraminidase is replaced by a decrease in P value in PES-PEG or Aquaphase-PEG systems. We conclude that PES (and Aquaphase) can be substitutes for dextran in cell partitioning studies when charge-sensitive phases are used (e.g., those containing phosphate) while separations based on properties reflected by Dx-PEG systems containing sodium chloride are not duplicated by PES-PEG (and probably not by Aquaphase-PEG). The hydroxypropyl starch-PEG systems containing sodium chloride, unlike the analogous Dx-PEG systems, have a significant electrostatic potential difference between the phases.

Aging↗
PubMed1988

Detection of surface differences between closely related cell populations by partitioning. Cultured K-562 cell sublines.

The K-562 cell line is a culture of human leukemia stem cells originally derived from a patient with chronic myelogenous leukemia in blast crisis. We have applied a sensitive method capable of detecting subtle differences in charge-associated and noncharge-related cell surface properties between closely related cell populations to K-562 cells from different sources and having different histories. The method consists of isotopically labeling aliquots of each of two cell populations to be compared with 51Cr-chromate and mixing the labeled cells with an excess of unlabeled cells with which they are to be compared. The mixtures are subjected to countercurrent distribution in either a charge-sensitive or a noncharge-sensitive dextran-poly(ethylene glycol) aqueous two-phase system. The distribution curves are analyzed for total cells (in terms of electronic counts) and labeled cells (in terms of cpm). Alterations in relative specific activities through the distribution curves are indicative of differences in surface properties between such cell populations. Using this method we have found surface differences, both charge-associated and noncharge-related, between any two K-562 cell sublines examined. Interestingly, whereas we observed differences among K-562 sublines, we never witnessed a change in surface properties of the respective sublines. The differences among the sublines examined remained unaltered for more than 40 passages in our hands. It thus appears likely that the event(s) leading to an altered K-562 cell surface, detectable by partitioning, does not occur gradually.

Cell Line↗
PubMed1988

The course of alcoholism. Long-term prognosis in different types.

The disease concept of alcoholism was first introduced into the medical literature by Magnus Huss in 1984. Since that time many authors have attempted to define therapy-related sub-groups of chronic alcoholics but have been unsuccessful until now because alcoholism represents a complex development and becomes apparent in various clinical pictures. As the method of cross-sectional investigations does not seem to be able to produce reliable results, we performed a prospective long-term study of 444 alcoholics. The methodological claims in literature were taken into consideration like selection criteria, programmes and goals of therapy, follow-up rate and time, etc. Careful observation of the pertinent parts of the pathogenetic pathway leading to chronic alcoholism enabled the authors to establish 4 sub-groups of alcoholics relevant for treatment.

Alcohol Drinking↗