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W Bruns

Publications and source records attributed to W Bruns.

At least 37 records · Page 2Linked to original sources
PubMed1992

Carbonic anhydrase in skeletal and cardiac muscle from rabbit and rat.

We have studied the distribution of carbonic anhydrases (CA) in several skeletal muscles of the hindlimb of rabbits and rats and in cardiac muscle of the rabbit. To remove erythrocyte CA, hindlimbs and hearts were thoroughly perfused with dextran solution, and the effectiveness of the perfusion was in most cases assessed by determining the contamination of the muscles with radioisotopes that had been used to label the erythrocytes before the perfusion was started. We observed three forms of CA: (1) cytosolic (sulphonamide-resistant) CA III; (2) a cytosolic sulphonamide-sensitive CA, probably isoenzyme II; (3) a membrane-bound form that was extracted from the particulate fraction using Triton X-100. These CA isoforms were distributed as follows. (1) CA III is located in the cytoplasm of slow, oxidative skeletal muscles and is absent from or low in fast skeletal and cardiac muscle; this holds for rabbits and rats and is identical with the pattern previously described for several other species. (2) The cytosolic sulphonamide-sensitive CA is present in fast rabbit muscles and absent from slow muscles of this species. In contrast, all skeletal muscles of the rat studied here lack, or possess only very low, activity of this isoenzyme. (3) The membrane-bound form of CA is present in all rabbit muscles studied; its activity appears somewhat higher in fast than in slow skeletal muscles. (4) Cardiac muscle constitutes an exception among all striated muscles of the rabbit as it possesses no form of cytosolic CA but a high activity of the membrane-bound form.

Animals↗
PubMed1992

Membrane-bound carbonic anhydrase in the heart.

Microsomal membranes from bovine heart homogenates were subfractionated by density gradient centrifugation. Fractions with high levels of a sarcolemmal (SL) marker are enriched in specific carbonic anhydrase (CA) activity up to ninefold compared with the microsomes. Fractions with high levels of a sarcoplasmic reticulum marker and a mitochondrial marker, respectively, exhibit specific CA activities that are similar to the one found in the microsomes. Determination of cytosolic markers reveals that the CA activity in the SL fraction is not due to contamination by cytosolic CA, and it is shown by Triton X-114 phase separation that the CA activity is due to an integral membrane protein. In cryosections from rabbit heart the SL region of cardiomyocytes is stained by the fluorescent CA inhibitor dansylsulfonamide. Intracellular staining occurs also, with a pattern suggesting the presence of CA associated with intracellular membranes. Although it cannot be excluded that there is a contribution by endothelial membranes, it appears likely that most CA of the heart is bound to the SL. The possible involvement of the enzyme in extracellular proton buffering is discussed.

Animals↗
PubMed1991

[Treatment of type 2 (non-insulin dependent) diabetes and the metabolic syndrome with diet].

Insulin resistance appears as the pathophysiological basis of metabolic syndrome and NIDDM. In type 2 diabetics additionally we observe a delayed and prolonged postprandial insulin response. These both processes represent a pathophysiological and pathogenetic unity of disturbances. The prevention and therapy of insulin resistance, metabolic syndrome and type 2-diabetes with diet involves 3 main issues: reduction of energy uptake and of body weight in obese; Composition of meals concerning the principles of fat reduced lactovegetabile nutrition; guaranteeing of longer postabsorptive phases (between meals), to avoid a permanent postprandial hyperinsulinemia and development of insulin resistance. Anti-insulin resistance diet is therefore a carbohydrate enriched, fat-reduced (lactovegetabile) nutrition with not too frequent meals (longer meal-free phases) and mainly reduced energy intake in overweight.

Arteriosclerosis↗
PubMed1990

[New knowledge of diet therapy of type 2 (non-insulin-dependent) diabetes].

The composition of the diet of the type II-diabetics should correspond to the principles of a lactovegetarian diet: relatively many carbohydrates, vegetables, fruits and little fat, in particular little animal fats. By such a pathogenetically orientated nutrition one is at the earliest able to treat successfully preventively and therapeutically the development of the arteriosclerosis which is connected with the type 2 diabetes and with metabolic syndrome. Thereby the weight reduction is of course integrated into such a dietary prescription. The number of meals a day should not routine-like be established to 5 to 6, and only in a bad metabolic condition the subdivision into many smaller meals is necessary. In the calculation of the food type 2 diabetics with overweight stabilised on diet alone should estimate the energy of food and reduce it. At this stage the calculation of carbohydrates is not necessary. Only when a blood sugar decreasing therapy is added (insulin and perhaps sulfonylureas) we have additionally to begin the calculation of carbohydrates. In order to obtain a useful compliance unnecessary reglementations must be removed so that only there where necessary a strict discipline is observed.

Blood Glucose↗
PubMed1990

[Nocturnal continuous subcutaneous insulin infusion--a therapeutic possibility in labile type I diabetes under exceptional conditions].

The whole-day continuous subcutaneous insulin infusion (CSII) with portable pumps in daily blood glucose autocontrol guarantees a more stabile and favourable glycaemia than multiple injections in labile type I diabetics. The success is mainly to be traced back to the continuous replacement of the basal secretion, particularly to the nocturnal fasting phase. In this study the effect on the glycaemia is investigated with exclusively nocturnal administration of the CSII under maintenance of multiple insulin injections during this day. In a group of 18 type I diabetics the nocturnal CSII in comparison to intermediate insulin administrations in the evening led to a significant improvement of glycaemia (p less than 0.01), in particular to the decrease of the fasting blood sugars (p less than 0.05). In two casuistic observations in comparison to all the other conventional methods for the compensation of the nocturnal glycaemia (depot insulin, nocturnal injection of normal insulin) the nocturnal CSII proved to be superior. Therefore, the nocturnal CSII is an--though more rarely to be used--alternative, which may be taken into consideration, of a whole-day CSII is temporarily unwished for.

Adult↗
PubMed1990

Development of a medical-psychiatric program within the private sector. Potential problems and strategies for their resolution.

Recent reports regarding the development of combined medical-psychiatric units have primarily involved units operated under the auspices of academic medical centers. Almost no published information is available regarding the fiscal, administrative, or clinical feasibility of operating such programs within the context of the private community hospital setting. This article outlines the organization and development of such a private unit and discusses the various medical, administrative, political, and financial considerations that must be evaluated in planning for the successful operation of medical-psychiatric units within the private sector.

Cost Control↗
PubMed1990

A prospective study of the hazards of multiple use of disposable syringes and needles in intensified insulin therapy.

The aim of the present study was to evaluate the potential hazards of multiple use of disposable syringes and needles for insulin injections over a long period of time. A special syringe container (pen-case) was developed to carry the syringe with insulin. In the microbial trial 24 patients, each injecting insulin for 1 week with one disposable needle, were studied for 201 patient-weeks with 5829 injections. Cultures of 154 needles, 155 syringe rinses, 154 pen-case rinses and the remains of insulin in 201 vials revealed no relevant contamination. In the clinical trial 100 diabetic patients were followed up for up to 7 years. Each syringe was reused for 1 to 12 weeks and each needle for 1 to 40 days (4 to 200 injections). Only sporadic redness not exceeding 4 mm2 was seen at sites of about 560,000 insulin injections. Thus, the repeated use of syringes and needles in one diabetic patient may be recommended as a convenient and safe approach in insulin administration.

Bacteria↗
PubMed1989

Implications of an intracorporeal glucose sensor in the management of diabetic patients.

Long-term hyperglycemia is the main cause of diabetic late complications (angiopathy, neuropathy). The problem of lifelong management of diabetes is to guarantee near-normal glycemia. Since the introduction of self-monitoring of blood glucose by means of extracorporeal devices on the basis of strips, an important improvement of metabolic management of diabetic patients has become possible. In order to further improve the control of glycemia, the following steps of an evolving system of electrochemical glucose sensing and monitoring should be envisaged: (1) fast-acting extracorporeal glucometers for incidental analyses, (2) intracorporeal sensors for short-term but easily repeated use to follow any kind of open-loop insulin therapy and to provide appropriate hypoglycemia-warning signals, (3) intracorporeal sensors as an essential part of automated feedback-controlled systems for insulin delivery. Approximately 4000 patients per million of the population might benefit from the latter version of intracorporeal glucose sensors. In closed-loop blood glucose control, however, pathophysiological problems may arise from the sole application of negative feedback control in the glucose-insulin algorithm.

Biosensing Techniques↗
PubMed1988

Human pancreatic secretory trypsin inhibitor (PSTI) produced in active form and secreted from Escherichia coli.

As a basis for a protein design project, we decided to produce the human pancreatic secretory trypsin inhibitor (PSTI) in its active form. Total gene synthesis was carried out efficiently by (i) computer design of the gene fragments, (ii) synthesis of the oligodeoxynucleotides by the segmental support method, and (iii) assembly of double strands under optimized ligation conditions. Fusion to the ompA gene signal peptide led to secretion of processed PSTI in various constructions, with or without additional amino acids (aa) at the N-terminus. The secreted proteins (56 to 63 aa) were biologically active, suggesting that the three cysteine bridges were correctly formed. Surprisingly, after induction the product was found almost exclusively in the culture medium. Variants of PSTI with Asp or Asn at aa positions 21 and 29 [sequences published by Greene et al., Methods Enzymol. (1976) 813-825, and by Yamamoto et al., Biochem. Biophys. Res. Commun. (1985) 605-612] showed the same Ki for both human and porcine trypsin.

Amino Acid Sequence↗
PubMed1987

Extracellular and membrane-bound beta lactamase of Staphylococcus aureus: their importance for the expression of penicillin resistance.

The synthesis and excretion of beta lactamase by several strains of Staphylococcus aureus from different clinical sources and the ability of both the extracellular and membrane-bound enzyme to mediate penicillin resistance was studied. When beta-lactamase production was maximally induced with penicillin G or ampicillin, about 50% of the beta lactamase was excreted from the cells, the amount of extracellular enzyme correlating well with the degree of resistance established by an in-vitro test model. From penicillin-binding experiments it became apparent, however, that the membrane-bound beta lactamase can also constitute a barrier, strong enough on its own to prevent penicillins from reaching their target. This could be of clinical relevance if, under certain conditions in vivo, the extracellular beta lactamase is insufficient for full protection of the staphylococcal cells.

Cell Compartmentation↗
PubMed1986

Carbonic anhydrase in the sarcoplasmic reticulum of rabbit skeletal muscle.

Sarcoplasmic reticulum vesicles and mitochondria were prepared from red and white skeletal muscles of the rabbit. The preparations were characterized in terms of their specific activities of citrate synthase, basal (Mg2+-dependent) and Ca2+-dependent ATPase (the latter two in the presence of NaN3 and ouabain), and their specific carbonic anhydrase activities were determined. Skeletal muscle mitochondria had high specific activities of citrate synthase (700-1200 mu. mg protein-1) and low carbonic anhydrase activities (0.1-0.4 u. ml mg protein-1). The latter are likely to be due to a contamination of the preparations with sarcoplasmic reticulum (s.r.) Preparations of s.r. vesicles showed negligible activities of citrate synthase and the expected differing patterns of basal and Ca2+-dependent ATPase in red and white muscles. Specific carbonic anhydrase activities in s.r. from both muscle types were high (2-4 u. ml mg protein-1). The highest carbonic anhydrase activity, 11 u. ml mg protein-1, was found in s.r. from rabbit m. masseter. The inhibition constant of s.r. carbonic anhydrase towards acetazolamide was 4-6 X 10(-8) M and similar but not identical to that of cytosolic carbonic anhydrase II. It appears possible that the carbonic anhydrase II-like enzyme previously found by us in muscle homogenates (Siffert & Gros, 1982) originates from the s.r. Histochemical studies using the dansylsuphonamide method described previously (Dermietzel, Leibstein, Siffert, Zamboglou & Gros, 1985) showed an intracellular pattern of carbonic anhydrase staining compatible with the presence of the enzyme in s.r.: spots homogeneously distributed across the fibre cross-sections in transversely sectioned fibres and thin, longitudinally oriented, bands in longitudinally sectioned fibres. It is estimated that s.r. carbonic anhydrase accelerates CO2 hydration within the s.r. approximately 1000-fold. Thus, CO2 and HCO3- react fast enough to provide a rapid source and sink for protons leaving and entering the s.r. in exchange for Ca2+.

Acetazolamide↗
PubMed1985

Suppression of intrinsic resistance to penicillins in Staphylococcus aureus by polidocanol, a dodecyl polyethyleneoxid ether.

With polidocanol, it was possible to reduce the MIC as well as the MBC of methicillin, oxacillin, penicillin G, and ampicillin against resistant staphylococci. The strongest effects were obtained with methicillin and oxacillin. All strains tested could be resensitized to these penicillins independent of the original resistance levels. Polidocanol was not inhibitory by itself for Staphylococcus aureus. Furthermore, it did not inhibit the activity of staphylococcal beta-lactamase. This permits the conclusion that an intrinsic resistance mechanism is affected by this substance. Its action cannot be simply explained by an improved accessibility of the penicillin targets as uptake, and binding of methicillin and penicillin G in resistant cells was not changed by polidocanol. On the other hand, the lysis induced by combinations of this substance with small amounts of a penicillin was antagonized by chloramphenicol. This suggests that autolytic enzymes are involved in the polidocanol effect and possibly in the intrinsic resistance mechanism itself. Before polidocanol can trigger lysis, the penicillin must act first in some way. As could be seen with a susceptible strain, the resulting lysis did not exceed that obtained with penicillins alone. Thus, polidocanol does not exhibit an independent lytic mechanism but obviously is able to substitute penicillins in their lytic action.

Ampicillin↗
PubMed1985

Structure of the penicillin acylase gene from Escherichia coli: a periplasmic enzyme that undergoes multiple proteolytic processing.

Penicillin acylase is processed from a 90-kD precursor through the cleavage of a leader peptide and two further endopeptidase cleavages to yield an enzyme that contains a 22-kD (or 23-kD) and a 65-kD subunit. The endopeptidase cleavages require an intact carboxy terminus. This type of processing appears to be unique for a prokaryotic enzyme, having its most closely related analog in the synthesis and processing of preproinsulin and other eukaryotic hormones.

Amidohydrolases↗
PubMed1984

Long-term improvement in metabolic control of unstable type I diabetes by s.c. insulin injection patterns based on the dose profiles required by bed-side artificial beta-cell.

Twenty unselected unstable type I diabetic inpatients whose blood glucose control was insufficient employing three daily s.c. injections of regular insulin supplemented by intermediate acting insulin were subjected to a 48-hour treatment with the Biostator -GCIIS when both diet and muscular exercise were kept as close as possible to the conditions at home. The s.c. injection regimen was adjusted to the insulin dose pattern required by the artificial beta cell. There was significant metabolic improvement in 16 out of the 20 patients on discharge, in comparison to the pre-Biostator conditions. This improvement was still present when the patients were re-admitted after an average of seven months. It is concluded that in certain cases of unstable type I diabetes mellitus the metabolic re-arrangement based on intercalary days on an extracorporal artificial beta cell might be useful if the control constants are adapted to minimize the insulin requirement by the machine.

Adolescent↗