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Biomedical subjects

H Holzer

Publications and source records attributed to H Holzer.

At least 127 records · Page 7Linked to original sources
PubMed1981

[The importance of aluminiun in dialyseencephalopathie (author's transl)].

64 patient on chronic haemodialysis were investigated. The duration of the dialysis was 44 months; the mean age of patients was 41 years. In 6 patients a diagnosis of Dementia was made in addition to apraxia, dysarthria and anarthria. 5 of the patients died. All the demented patients showed an abnormal EEG and 4 had atrophy in the computertomogram. The plasma aluminium levels were significantly raised (409 microgram/l) in the demented group as compared to the non-demented dialysis patients (189 microgram/l).

Adult↗
PubMed1981

Initiation of selective proteolysis by metabolic interconversion.

After the addition of glucose to acetate- or ethanol-grown yeast cells a small group of selected enzymes is rapidly inactivated. This phenomenon has been called "catabolite inactivation". Among other enzymes participating in gluconeogenesis, fructose-1,6-bisphosphatase is inactivated during this catabolite inactivation process. It was shown by FUNAYAMA et al. (Eur. J. Biochem. 109, 61-66 (1980)) that the mechanism of inactivation is proteolysis. In the present paper evidence is presented that after addition of glucose a covalent conversion of the enzyme protein by phosphorylation of a serine-residue initiates its subsequent proteolysis. It is suggested that the covalent modification triggered by glucose and/or products of its catabolism renders the enzyme susceptible to proteinases and thereby initiates proteolysis of a selected enzyme without the necessity of a specific proteinase present.

Endopeptidases↗
PubMed1981

[Therapy of hypertensive crises with a mono-substance with alpha- and beta-blocking properties (labetalol)].

For treatment of hypertensive emergencies 36 patients received an intravenous bolus of 100 mg labetalol. The mean blood pressure of the whole group was decreased from 220/128 mm Hg to 167/107 mm Hg. Mean heart rate dropped from 85 to 76 per minute. 7 patients did not respond to treatment. Thereafter 4 patients received a second dose of 100 mg or 500 mg labetalol respectively, whereupon 2 showed a distinct drop in blood pressure. Simple handling and intensive efficacy and the lack of troublesome side effects recommend labetalol for the treatment of hypertensive emergencies.

Adult↗
PubMed1981

The effects of haemodialysis on cerebral blood flow.

Cerebral blood flow (CBF ml/100g/min) was measured by 133Xenon in 24 patients before and after haemodialysis (HD) and in 27 normal persons. A wide scatter of the absolute CBF values were observed to correlate with the haematocrit, whereas blood pressure, pCO2 and weight loss during HD did not. Before HD, when compared with the control group, the patients showed a distinct elevation of CBF due to the severe anaemia of this group. Though there was only a slight increase in haematocrit post-dialysis a return to normal of the post-dialysis CBF was observed. In order to achieve comparative data the CBF values were corrected mathematically to a normal haemoglobin (160g/L) and the adjusted mean pre-dialysis CBF value was within the normal range and decreased to the lowest limit of normal after HD. A significant decline in CBF was observed with increasing age and length of time on HD. When compared with normal the age-dependent decline was about twice as high and showed a 10-fold decrease with the time on HD treatment. When we grouped the patients with regard to the CBF values the following results were obtained: in eight patients CBF was elevated before HD and showed a return to normal after HD. These were younger patients with greater predialysis over-hydration and lower blood pressure. A distinctly reduced CBF was observed in nine patients and remained unchanged after HD. This group included older patients with a higher blood pressure. The reaction of CBF suggests three types of patients with different vascular reactivity to fluid excess: young normotensive patients with high vascular fluid storage capacity, patients with hypertensive vascular reactivity and patients with vascular damage.

Adolescent↗
PubMed1980

Purification and properties of proteinase A from yeast.

Proteinase A (EC 3.4.23.6) was purified from commercial bakers' yeast in five steps, including hydrophobic chromatography and affinity chromatography. After the last step the enzyme appeared homogeneous on polyacrylamide gel electrophoresis and in the analytical ultracentrifuge. A molecular weight of 41,500 was determined for proteinase A. The amino acid composition includes 43% polar residues and 12% aromatic amino acids. Proteinase A is a glycoprotein containing 7.5% mannose and 1% of glucosamine and galactosamine. The temperature and the pH stability of the enzyme have been determined. At pH 6, the proteinase exhibits a remarkable stability even in 6 M urea. Proteinase A splits hemoglobin with an optimum at pH 3.0 and casein and azocasein with an optimum at pH 6.0. The enzyme is inhibited by pepstatin, diazoacetyl-DL-norleucine methyl ester and by 1,2-epoxy-3-(4-nitro-phenoxy) propane.

Amino Acids↗
PubMed1980

Interaction of proteinases and their inhibitors from yeast. Activation of carboxypeptidase Y.

In a crude extract of baker's carboxypeptidase Y is predominantly found in an inactive form. A procedure for the isolation of the inactive form of the enzyme is presented. It is shown that the inactive form is identical to the reconstituted complex of carboxypeptide Y with its inhibitor. This complex is stable above pH 5, i.e., it remains inactive between pH 5 and 9. The conversion to the active enzyme occurs below pH 5, also in the absence of proteolytic enzymes. The inhibitor of carboxypeptidase Y can be removed enzymatically from the complex by treatment with proteinase B (EC 3.4.22.9) at pH 7. At pH 5, the carboxypeptidase Y-inhibitor complex is activated both by proteinase A (EC 3.4.23.6) and B. Yeast proteinases are activated in a crude extract by incubation at pH 5 [3]. Based on the levels of proteinase A and B in an activated extract and on the time required for conversion to active carboxypeptidase Y, proteinase B is at least 10-times more effective than proteinase A. Peptides that arise during the pH 5-incubation procedure did not accelerate the proteolytic activation of carboxypeptidase Y. The inhibitor of carboxypeptidase Y is completely degraded in the proteolytic activation steps, no accumulation of intermediates is observed. Only one form of active carboxypeptidase Y is found to be present in the proteolytically activated extracts, i.e., no polypeptide fragments of carboxypeptidase Y-inhibitor remain bound to the enzyme after it has been activated by proteinase B. In vacuoles prepared from spheroplasts no inactive carboxypeptidase Y can be detected.

Aspartic Acid Endopeptidases↗
PubMed1980

[Results of computerized tomography of the skull in hemodialysis patients].

Psychiatric and neurological symptoms as well as the clinical diagnosis of 22 patients on chronic hemodialysis were set in contrast with the findings of the cranial computerized tomography. The cranial computerized tomography turns out to be a valuable diagnostic aid to recognise or exclude morphologic lesions in the central nervous system, particularly because the complex overlap of the various pathogenetic mechanisms in hemodialysed patients points out frequently the little value of the clinical symptoms.

Adult↗
PubMed1980

[Virus hepatitis B in hemodialysis wards: ways of distribution and possibilities of their interruption (author's transl)].

An attempt was made to describe differentiated problems in connection with virus hepatitis B in hemodialysis wards in a form as brief and precise as possible and to present some suggestions as to the elimination of this insidious disease. A through consideration of the hepatitis question yielding to a well established and legally sanctioned prevention concept would not only be of great importance to hemodialysis patients and their family members and the dialyses personnel but it would also play a great role for the protection of the general population. Finally, a statement by Baruch Blumberg (Nobel Price winner in Medicine, 1976) should visualize the universal importance of the hepatitis question once more: "If we succeeded in bringing hepatitis B under control, this would bring about a reduction of the rate of chronic liver diseases and of primary liver carcinoma."

Austria↗
PubMed1980

[The natural history of dialysis encephalopathy (author's transl)].

18 data with etiopathogenetic relations to the dialysis encephalopathy, such as plasma aluminum levels, parameters of azotemia and parathyroid function, blood pressure, IQ, and EEG-findings, were compared between 5 patients suffering with encephalopathy and 54 dialysis-patients without neurological symptoms. The investigations, including statistical computations (variance analysis, multiple linear regression, multivariate analysis) elicited the following results: 1. All patients suffering from encephalopathy showed higher plasma aluminum concentrations (505 +/- 58 microgram/L : 228.9 +/- 213 microgram/L, p = greater than 0.01), higher serum calcium levels (2.48 +/- 0.15 mmol/L : 2.35 +/- 0.11 mmol/L, p = less than 0.001), higher rates of osteopathy and abnormal EEG's (5 of 5 : 7 in 41 patients). 2. Age, duration of dialysis treatment, quality of dialysis treatment, blood pressure, did not show any pathogenetic influence. 3. Hyperaluminemia was caused by the oral administration of aluminum hydroxide. After reduction of the daily dose from originally 6.18 +/- 3.24 gm to 1.52 +/- 0.45 gm, the plasma aluminum levels decreased to 54.05 +/- 34.59 microgram/L without any adverse effects on the serum phosphate levels. The results suggest that dialysis-patients need less AI-OH than is usually indicated. 4. Encephalopathy did not occur after normalisation of plasma aluminum levels. 5. With respect to the aluminum toxicity in dialysis-patients, dialysis encephalopathy should not be classified as a complication of multifactorial etiology. Only hyperparathyroidism seems to be an additional risk factor.

Adult↗
PubMed1980

[Measurement of the colloid osmotic pressure from plasma density by means of the mechanical oscillator technique (author's transl)].

The colloid osmotic pressure of plasma is a clinically and physiologically important variable. Like the plasma density, it is a function of the total concentration of plasma proteins. Thus, plasma colloid osmotic pressure can be determined from measurement of the plasma density. Minor variations are caused by variations of the albumin-globulin ratio and, much less frequently, by increased concentration of low molecular substances in the plasma. The direct measurement of the colloid osmotic pressure is a time consuming and complex procedure. The determination of the plasma density using the mechanical oscillator technique is a simple and fast procedure. From our results we were able to derive and prove the applicability of an equation which permits the calculation of the colloid osmotic pressure from the measured values of the plasma density. The plasma volume needed for the measurement is 0.2 ml, the measuring time amounts to a few seconds.

Blood Proteins↗
PubMed1980

["Fatty neck." Symmetrical lipomatosis with Madelung's symptom (author's transl)].

The relatively rare disease of symmetrical lipomatosis is described on the basic of six own observations. For many years five patients worked with asphalt and one was a coal-miner. Because of this professional exposition oil and cole products are considered to be reason for this disease. The still unknown aetiology and pathogenesis are discussed and finally the surgical therapy is presented.

Head and Neck Neoplasms↗