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Biomedical subjects

W Wilke

Publications and source records attributed to W Wilke.

At least 37 records · Page 2Linked to original sources
PubMed1989

In situ calibration of implanted electrochemical glucose sensors.

A feasible and reliable method of in situ checking and calibration of implanted glucose sensors is required to compensate for alterations in the overall sensitivity of the "sensor plus subcutaneous fluid glucose compartment" system. In a study on nondiabetic dogs, the linear regression analysis of paired plasma glucose/sensor current data is validated as a potential basis of recalibration of intracorporal glucose sensors. These sensors were amperometric glucose oxidase/hydrogen peroxide electrodes of which the in vitro response time to square alterations in the ambient glucose concentration T95 was less than 5 min. The method presented may be incorporated into the data handling system of portable glucose monitors or of miniaturized artificial beta-cells. For its performance, no steady state glycaemia but a minimum alteration in the intracorporal glucose concentration is needed. The latter can be provided both by tests or by fluctuations as they occur spontaneously during the course of the day.

Animals↗
PubMed1988

[Initial experiences in the use of pulsatile Gn-RH administration for ovulation induction].

In 9 patients the pulsatile administration of Gn-RH for the induction of ovulation was given in 13 treatments, we used the minipump Zyklomat of the firm Ferring and a Gn-RH pump from ZID Karlsburg. The administration was carried out for 10 to 18 days with dosages from 2.5 to 20 micrograms Gn-RH per pulse. 9 patients did ovulate and 5 patients became pregnant.

Adult↗
PubMed1986

Correlation between the light diffraction pattern and the structure of a muscle fibre realized with Ewald's construction.

Ewald's construction of reciprocal space is used to explain the diffraction pattern obtained by illumination of a skeletal muscle fibre with laser light. The question of whether the illuminated fibre segment acts as a monocrystal or as a conglomerate of crystallites is answered by determining the longitudinal extension of the layer lines; neither the whole muscle fibre nor the single myofibril acts as the diffracting unit. The characteristic fine structure within a layer line ('streaks') is explained by Ewald's formalism as being caused by diffraction from partial volumes of the illuminated fibre segment. These partial volumes constitute the main diffracting units. Any cross-section of a 100 micron diameter fibre contains 3-6 such units. They are delineated from each other by the skew of the diffracting planes with respect to the fibre axis, and possibly by small differences in sarcomere length. Within a unit, skew angle and sarcomere length are nearly constant. Light intensity measurements along the length of a layer line at various tilt angles (omega) between fibre and beam axis provide an overview of the size and the skew angle of the various diffracting units within the illuminated fibre segment. The cross-sections of the diffracting units were measured in 'mini'-omega-scans of streaks created by them and from the maximal streak length. In general, the units had noncircular cross-section, the length of the main axis ranging between 10 micron and the fibre diameter. The axial extensions of the diffracting units determined in fibre length scans was 100-300 micron. The results of diffraction experiments reported in the literature as well as the data from light and electron microscopy are in agreement with the fibre structure suggested above. Sarcomere length determination by light diffractometry is discussed within the framework of the Ewald formalism, and recommendations for an experimental procedure are given.

Animals↗
PubMed1983

Pituitary and adrenal hormones in patients after myocardial infarction under ergometer load.

The levels of human growth hormone (HGH), ACTH and cortisol in the plasma of 100 middle-aged men were measured by means of radioimmunoassay (12 patients in the phase of hospitalization after myocardial infarction, 47 patients in convalescence, 31 patients in post-convalescence, 10 healthy men). Twenty patients in the phase of convalescence and all patients in post-convalescence did exercises on bicycle ergometer with submaximal loading. Patients after myocardial infarction showed significantly lower basic levels of HGH than healthy persons, and the increase in the HGH level induced by exercise was significantly lower. The hormones ACTH and cortisol showed only slight differences. The secretion of the pituitary hormones, mainly HGH, seems to be altered in patients after myocardial infarction.

Adrenocorticotropic Hormone↗
PubMed1975

Determination of total insulin (TIRI) in plasma of insulin-treated diabetics and newborn infants of insulin-treated diabetic mothers.

Plasma of insulin-treated diabetics and of newborn infants of insulin-treated diabetic mothers contains insulin antibodies which invalidates the radioimmunoassay of insulin. Therefore, the endogenous insulin antibody complex must be splitted at a pH lower than 5 and the total IRI (TIRI) is separated by ethanol extraction. It was investigated the recovery rate in dependence upon plasma volume used for extraction. By reduction of used plasma volume from 500 to 200 mul per extraction the recovery rate was increased from 65.1 +/- 8.4 to 88.3 +/- 4.2% (mean +/- SEM). The low plasma volume of 200 mul for TIRI extraction made it possible to determine TIRI during glucose loads of newborn infants. To eliminate different conditions of incubation for standard and unknown plasma samples the TIRI levels were computed by means of so-called "extracted" standard curve, obtained with extracted insulin from standard insulin dilution in insulin-free pooled human plasma. Using the described method a temporary regeneration of insulin secretion of a newly diagnosed juvenile diabetic after insulin treatment could be shown. In contrast to newborn infants of healthy mothers a biphasic/insulin release was found during the intravenous glucose loads in newborn infants of insulin-treated diabetic mothers.

Adult↗
PubMed1970

Fraktionierung handelsüblichen Insulins (IV) Gewinnung hochgereinigten Insulins mit Hilfe der Polyacrylamid-disc-elektrophorese und Ermittlung seiner hypoglykämischen Aktivität.

From proinsulin-free insulin we obtained maximal purified insulin by means of preparative polyacrylamide electrophoresis (PADE). This substance appears in the analytical PADE as a uniform band and possesses glycine and phenylalanine as N-terminal amino acids. By use of the eviscerated rabbit as testing model, the product displays a higher hypoglycemic activity as compared with the Toronto standard.

Journal Article↗