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Biomedical subjects

W Haase

Publications and source records attributed to W Haase.

At least 145 records · Page 8Linked to original sources
PubMed1984

Characterization of calcium uptake into rough endoplasmic reticulum of rat pancreas.

ATP-dependent Ca2+ uptake into isolated pancreatic acinar cells with permeabilized plasma membranes, as well as into isolated endoplasmic reticulum prepared from these cells, was measured using a Ca2+ -specific electrode and 45Ca2+. Endoplasmic reticulum was purified on an isopycnic Percoll gradient and characterized by marker enzyme distribution. When compared to the total homogenate, the typical marker for the rough endoplasmic reticulum RNA was enriched threefold and the typical marker for the plasma membrane Na+,K+(Mg2+)ATPase was decreased 20-fold. When different fractions of the Percoll gradient were compared, 45Ca2+ uptake correlated with the RNA content and not with the Na+,K+(Mg2+)ATPase activity. The characteristics of nonmitochondrial Ca2+ uptake into leaky isolated cells and 45Ca2+ uptake into isolated endoplasmic reticulum were very similar: Calcium uptake was maximal at 0.3 and 0.2 mmol/liter free Mg2+, at 1 and 1 mmol/liter ATP, at pH 6.0 and 6.5, and free Ca2+ concentration of 2 and 2 mumol/liter, respectively. Calcium uptake decreased at higher free Ca2+ concentration. 45Ca2+ uptake was dependent on monovalent cations (Rb+ greater than K+ greater than Na+ greater than Li+ greater than choline+) and different anions (Cl- greater than Br- greater than SO4(2-) greater than NO3- greater than I- greater than cyclamate- greater than SCN-) in both preparations. Twenty mmol/liter oxalate enhanced 45Ca2+ uptake in permeabilized cells 10-fold and in vesicles of endoplasmic reticulum, fivefold. Calcium oxalate precipitates in the endoplasmic reticulum of both preparations could be demonstrated by electron microscopy. The nonmitochondrial Ca2+ pool in permeabilized cells characterized in this study has been previously shown to regulate the cytosolic free Ca2+ concentration to 0.4 mumol/liter. Our results provide firm evidence that the endoplasmic reticulum plays an important role in the regulation of the cytosolic free Ca2+ concentration in pancreatic acinar cells.

Adenosine Triphosphate↗
PubMed1984

Binocular micromovement recording of human eyes:--methods.

An apparatus is described for binocular recording of micromovements of human eyes, with the contact lens mirror technique used frequently. Horizontal and vertical micromovements of both eyes are recorded simultaneously by means of instruments measuring light-spot positions. Spatial resolution of the measuring instrument is 12 s of arc, while the time resolution is 0.5 ms for this apparatus. The fixation mark (Snellen character) is at a distance of 5 m without any restrictions to the view. The micromovement data are registered by a microcomputer. A second computer enables precise calculation of the results which are given as multicoloured graphs (X/Y-, X/t-graph, velocity/t-graph, frequency analysis, phase correlation of both eyes). In this way the requirements are met for the clinical application of this measuring instrument on patients.

Contact Lenses↗
PubMed1984

[Correspondence of foveal and peripheral areas in subjects with intact binocular vision and patients with strabismus].

Findings on examination of the binocular correspondence often differ, depending on the methods employed. The authors looked for correspondence in cases of esotropia or manifest exotropia, measured bifoveolarly, foveo-peripherally and between two peripheral locations. Examination with the phase-difference haploscope revealed a tendency to harmonious anomalous correspondence at the periphery of the visual field; this was different from the bifoveal location, which remained unharmonious even when additional fusion stimuli seen by both eyes were given. In contrast to this result the correspondence of foveolae and periphery were found to be equal in cases of primary microstrabism.

Depth Perception↗
PubMed1984

Isolation of stable pancreatic zymogen granules.

Isolated pancreatic zymogen granules have been reported to lyse in common electrolyte solutions such as NaCl or KCl or at pH values above 5.5. A new method, based on an isosmotic Percoll density gradient, was developed for the isolation of zymogen granules and applied to rat pancreas. The granules are highly purified as judged by electron microscopic appearance and specific amylase activity. These granules exhibit a high degree of stability at physiological pH and in isotonic NaCl or KCl. Zymogen granule diameters, determined with a Coulter Counter, were 1.0 +/- 0.2 micron in either isotonic NaCl and KCl. These size values, obtained in physiological solutions, are comparable with granule sizes determined in intact cells by microscopy. Amylase activity averaged 0.66 microU per granule and protein content averaged 0.31 pg per granule; these values were not significantly influenced by different conditions of pH between 5.5 and 7.0 and ionic strength from near 0 to 0.15. The granule density estimated from the protein content was 1.13 g/ml, which agrees well with the behavior of granules in a density gradient. The properties of zymogen granules from the new preparation rectify the apparent discrepancy between their role as a storage organelle and their previously reported in vitro instability.

Animals↗
PubMed1984

Treatment of coronary heart disease with isosorbide mononitrate ('Elantan' 20): a multi-centre study in hospital and general practice.

An open, multi-centre clinical trial was carried out in 537 hospital patients and 2138 general practice patients to evaluate the efficacy and tolerance of isosorbide 5-mononitrate in the treatment of angina pectoris. Prior to entry into the trial, angina attack frequency and acute glyceryl trinitrate consumption were assessed during previous, in most cases unsatisfactory, anti-anginal therapy. After a treatment-free washout period of 3 days, graded multi-stage exercise testing was performed and then treatment started with 20 mg isosorbide mononitrate 3-times per day. Exercise testing was repeated after 14 days' therapy and, in the case of the hospital patients, also 4 to 5 hours after the first dose of isosorbide mononitrate. At the end of the 14-day treatment period, angina attack frequency and glyceryl trinitrate consumption were again assessed. Similar results were obtained for both hospital and general practice patients. Changing to isosorbide mononitrate resulted in a marked reduction in angina frequency, with complete elimination of angina attacks in approximately half of the patients; nocturnal angina, present in approximately 20% of the patients during previous therapy, virtually disappeared during isosorbide mononitrate therapy. Exercise tolerance and performance improved in the majority of patients, with a marked increase in the number of patients able to exercise to the level at which some symptom other than angina pectoris caused them to stop. ST-depression during exercise and exercise-induced arrhythmias also showed clear reductions during isosorbide mononitrate therapy. Tolerance to isosorbide mononitrate was good, the expected 'nitrate headaches' being the only common side-effect reported. The results were such that continuation of treatment with isosorbide mononitrate after the trial was recommended by the attending physician in 77% of the hospital patients and 87% of the general practice patients.

Adult↗
PubMed1984

Treatment of coronary heart disease with isosorbide mononitrate ('Elantan' 20).

An open, multi-centre trial was carried out to investigate the efficacy and tolerance of isosorbide mononitrate used as anti-anginal therapy in a large group of patients under normal general practice conditions. A total of 10,229 patients with coronary heart disease of average duration of 4 years entered the trial, of whom 8769 had sufficiently severe symptoms to be included in the analysis of results. Most of the patients (92.3%) had previously been treated with cardiovascular drugs. In the trial, all patients were treated with oral isosorbide mononitrate, 20 mg 3-times daily, for a period of 14 days. Treatment resulted in an improvement of angina (compared with the situation during previous therapy) in 79.9% of the assessed patients, complete abolition of angina attacks being achieved in 52.1% and a reduction in frequency of attacks in a further 28.7%. This reduction in angina was associated with a reduced acute consumption of nitrates used for the treatment of attacks. In the smaller sub-group of patients who had received no previous anti-anginal therapy, isosorbide mononitrate treatment resulted in improvement in 91% of patients, complete abolition being achieved in 77.5%. Nocturnal angina was almost totally eliminated by isosorbide mononitrate treatment and this can probably be explained in terms of the favourable pharmacokinetic profile of the drug. 'Nitrate headache', observed in 20.5% of the patients, was the only common side-effect of treatment. The absence of hypotension or tachycardia in significant numbers of patients indicates that isosorbide mononitrate should be well tolerated, as well as efficacious, in all patients with coronary heart disease.

Aged↗
PubMed1984

[Pharmacokinetics of a fluoride-calcium preparation for the treatment of osteoporosis].

The pharmacokinetics of fluoride and calcium were studied after administration of a combined fluoride and calcium preparation (Tridin) (1, 2 and 3 tablets) in 9 healthy male volunteers, using a cross-over study design. The total estimation of the pharmacokinetic data was performed by a simultaneous curve fitting to all single values, using a direct search procedure based on an open two-compartment model and three-compartment model, respectively. Maximum plasma concentrations and areas under the curve are proportional to the dose administered. Inter-subject variations are comparatively small, computerized multiple dose simulation for 3 days does not show any cumulation. The data fit the two-compartment model and the three-compartment model as well. The behaviour of the calcium concentrations reflects the immediate response of calcium homeostasis: plasma calcium concentrations are not affected.

Adult↗
PubMed1983

Isolation of basolateral membranes from columnar cells of the proximal colon of the guinea pig.

A method for an analytical isolation of plasma membranes from columnar cells (colonocytes) of the proximal colon of the guinea pig is described. Isolation of the colonocytes was performed by a mild EDTA-chelation method. After homogenization, two subsequent sucrose gradient centrifugations (isokinetic and isopycnic) yielded a plasma-membrane fraction which was enriched 12-fold in (Na+ + K+)-ATPase activity and 8-fold in adenylate cyclase activity. It is suggested that the purified membrane fraction consists mainly of basolateral membranes of the colonocytes. Due to the lack of suitable marker enzymes, no evidence for enrichment of the brush-border membranes was obtained. Histochemical studies demonstrated that alkaline phosphatase is absent from the luminal membrane of the surface epithelial cells of the proximal colon of the guinea pig.

Animals↗
PubMed1982

[Factors determining compliance in hypertensive patients].

The influence of various demographic, disease-related and therapeutic factors on compliance has been investigated in 110 patients with hypertension, heart failure or edema. While demographic factors such as age, sex, socioeconomic status, marital status and smoking habits, scarcely influenced drug adherence, duration of therapy showed the greatest compliance-lowering effect. In the 27 hospitalized patients compliance decreased in 3.2 weeks from 92.6% to 75% and in 83 outpatients from 83% to 56% in 17.8 weeks. Totally mean compliance of hospitalized patients was higher (86.9%) than in outpatients (79.7%). The percentage of fully compliant patients was also greater (74%) in hospitalized patients than in outpatients (54.2%). Patients with symptomatic diagnoses complied better than asymptomatic patients: Mean compliance rate was 87% (n = 17) in outpatients with heart failure or edema and 77.3% (n = 66) in hypertensive outpatients. Hypertensives with symptoms due to other diseases also showed a higher compliance (80%) than those with asymptomatic diagnoses (71.1%). New symptoms during therapy and side effects of the antihypertensive treatment decreased the percentage of compliers to 64% and 59% respectively. On the other hand, the severity of hypertension had no effect on drug adherence. Patients with systolic blood pressure values between 140 and less than 180 mm Hg showed an identical compliance (79.8%; n = 47) to those with systolic values greater than 180 mm Hg (79.9% n = 60).

Age Factors↗
PubMed1982

Calcium uptake into acini from rat pancreas: evidence for intracellular ATP-dependent calcium sequestration.

Intracellular ATP-dependent Ca2+-sequestration mechanisms were studied in isolated dispersed rat pancreatic acini following treatment with saponin or digitonin to disrupt their plasma membranes. In the presence of 45Ca2+ concentrations less than 10(-6) mol/liter, addition of 5 mmol/liter ATP caused a rapid increase in 45Ca2+ uptake exceeding the control by fivefold. ADP mimicked the ATP effect by 50 to 60%, whereas other nucleotides such as AMP-PNP, AMP-PCP, CTP, UTP, ITP, GTP, cAMP and cGMP did not. Maximal ATP-promoted Ca2+ uptake was obtained at 10(-5) mol/liter Ca2+. Inhibition of Ca2+ uptake by mitochondrial inhibitors was dependent on the Ca2+ concentration, indicating the presence of different Ca2+ storage systems. Whereas the apparent half-saturation constant found for mitochondrial Ca2+ uptake was approximately 4.5 X 10(-7) mol/liter, in the presence of antimycin and oligomycin (nonmitochondrial uptake) it was approximately 1.4 X 10(-8) mol/liter. In the absence of Mg2+ both ATP- and ADP-promoted Ca2+ uptake was nearly abolished. The Ca2+ ionophore and mersalyl blocked Ca2+ uptake, Electron microscopy showed electron-dense precipitates in the rough endoplasmic reticulum of saponin-treated cells in the presence of Ca2+, oxalate and ATP, which were absent in intact cells and in saponin-cells without ATP or pretreated with A23187. The data suggest the presence of mitochondrial and nonmitochondrial ATP-dependent C2+ storage systems in pancreatic acini. The latter is likely to be located in the rough endoplasmic reticulum.

Adenosine Diphosphate↗
PubMed1982

[A new test (C-test) for quantitative examination of crowding with test results in amblyopic and ametropic patients (author's transl)].

A new acuity test was developed with a defined space between symbols to determine the effect of crowding on visual line acuity. Landolt-C was used as a symbol and the space between symbols (either 2 to 3 min. of arc or 17 to 18 min. of arc) was kept constant for all acuity values. The test permits a quantitative examination of crowding phenomena. The experimental results obtained in measurements of visual line acuity in normal-sighted, amblyopic and ametropic subjects are presented. The results of treatment for amblyopia had evidently been interpreted too optimistically in many patients hitherto.

Adult↗
PubMed1982

Development of visual line acuity in humans.

An acuity test was developed with defined space between symbols to determine the effect of crowding on visual line acuity. The test differentiates between normalsighted subjects, those with low but uncorrected refractive errors and amblyopes. Furthermore, the test allows a quantitative examination of the crowding phenomenon and a measure of progress during amblyopia therapy. In normal-sighted subjects a maturational effect on visual line acuity was found, reaching the maximum test level at approximately the tenth year of life.

Age Factors↗
PubMed1982

[A simple method of assessing monocular visual acuity in nystagmus ].

Visual acuity examined with both eyes-binocularly-often shows a better result than monocular examination. The nystagmus intensity increases when one eye is occluded or vision is blurred by a plus lens. The authors suggest a simple method to examine visual acuity monocularly. The procedure is appropriate to preserve the attenuation of nystagmus under binocular condition.

Humans↗