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Biomedical subjects

A Voss

Publications and source records attributed to A Voss.

At least 19 recordsLinked to original sources
PubMed1992

[Incidence, frequency and resistance characteristics of methicillin-oxacillin resistant Staphylococcus aureus strains in Germany].

In a multicentre study, the methicillin-resistant Staphylococcus aureus (MRSA) isolates in 19 large clinics in Germany were recorded, and the resistance characteristics of these strains were studied. Oxacillin-mannitol-salt agar plates were distributed to all participants to ensure uniformity of screening, and each laboratory used these plates to investigate 200 consecutive Staphylococcus aureus isolates for oxacillin-methicillin resistance. Of the 3,794 evaluable Staphylococcus aureus isolates, 71.5% were penicillin and 3.7% (142) oxacillin resistant; four study centres reported methicillin-oxacillin resistance rates of more than 5%. Of the MRSA isolates, 75% were also resistant to ciprofloxacin, 61% to fosfomycin, 52% to imipenem, 50% to trimethoprim/sulfamethoxazole and 36% to clindamycin. All isolates were sensitive to vancomycin and teicoplanin. Of the Staphylococcus aureus strains isolated from patients in intensive therapy units, 10.4% were methicillin-oxacillin resistant. Drains and catheter tips (9.8% and 5.2% respectively) were the materials with the highest proportions of MRSA. Of the MRSA isolates in this study, 58.2% belonged to lysis group II.

Ciprofloxacin↗
PubMed1992

Differences in the interconversion between 20- and 22-carbon (n - 3) and (n - 6) polyunsaturated fatty acids in rat liver.

When male weanling rats were fed diets containing either 5% corn oil or a diet in which half of the corn oil was replaced by fish oil, the 20:5(n - 3) in liver choline and ethanolamine phosphoglycerides, not only partially replaced arachidonate but also paired with palmitic and stearic acids in the same molar ratio as did arachidonate. The 22:5(n - 3)/22:6(n - 3) ratio in the liver phospholipids of corn oil fed rats was similar to that found when the esterified levels of these two acids were increased 5-fold by feeding fish oil. Moreover, the pairing of both 22:5(n - 3) and 22:6(n - 3) with palmitic and stearic acids, on a molar ratio basis, was relatively independent of the total amount of esterified 22:5(n - 3) and 22:6(n - 3). When (3-14C)-labeled 22:4(n - 6) was injected into rats raised on a chow diet or incubated with hepatocytes from these animals, its primary metabolic fate was retroconversion to arachidonate followed by esterification. Conversely, [3-14C]22:5(n - 3) was a poorer substrate for retroconversion with a larger amount being esterified directly into phospholipids and, in addition, this acid served as a precursor for 22:6(n - 3). The enhanced metabolism of both [3-14C]22:4(n - 6) to 22:5(n - 6) and of [3-14C]22:5(n - 3) to 22:6(n - 3) in animals raised on a diet devoid of fat or in their hepatocytes may possibly be due to elevated 6-desaturase activity and/or the level of this enzyme or enzymes. This hypothesis is based on studies showing that the synthesis of 22:6(n - 3) proceeds via a pathway independent of a 4-desaturase but requires the use of a 6-desaturase at two steps (Voss, A., Reinhart, M., Sankarappa, S. and Sprecher, H. (1991) J. Biol. Chem. 266, 19995-20000).

Animals↗
PubMed1992

[Evaluation of the so-called basic cephalosporins using the serum bactericidal test].

The serum bactericidal activity (SBA) was studied one hour and four hours after intravenous administration of 1 g and 2 g cefotiam, 1.5 g cefuroxime and 2 g cefazolin to six volunteers. The 136 clinical isolates tested included Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis and Haemophilus influenzae. One hour after administration no significant differences in the activity against staphylococci were noted in the antibiotics tested. Four hours after administration of cefazolin 96% of the Staphylococcus aureus strains were killed at a serum dilution of 1:8, whereas only one strain was killed by cefuroxime and none by cefotiam under the same conditions. The highest SBA-titers against Haemophilus influenzae were achieved with cefotiam at a dosage of 2 g. SBA-titers against Escherichia coli, Klebsiella pneumoniae and Proteus mirabilis were higher after administration of 1 g cefotiam than after administration of 1.5 g cefuroxime and 2 g cefazolin, respectively.

Blood Bactericidal Activity↗
PubMed1992

Hypercalcemia in idiopathic myelofibrosis: modulation of calcium and collagen homeostasis by 1,25-dihydroxyvitamin D3.

A case of idiopathic myelofibrosis (IMF) presenting with hypercalcemia and hypercalcitriolemia is reported. It is proposed that ectopic production of the active vitamin D metabolite related to ongoing clonal expansion in the bone marrow accounts for the hypercalcemic state. Consistently low levels of circulating type I procollagen propeptide (PICP) and lack of progression of the bone marrow fibrosis during almost 6 months of follow-up point to an in vivo inhibition of type I collagen synthesis by 1,25-dihydroxyvitamin D3.

Adult↗
PubMed1992

Efficacy of fluconazole in the treatment of systemic fungal infections.

The efficacy of fluconazole in the treatment of systemic fungal infections was evaluated in an open non-comparative trial. A total of 48 patients with proven or suspected fungal infections were enrolled in 40 of whom efficacy was evaluable. Candida albicans accounted for 90% of the infections. Candida parapsilosis, Candida glabrata, Histoplasma capsulatum and Aspergillus fumigatus caused the infection in one case each. Fluconazole was administered at a dosage of 200-400 mg daily for a mean duration of 15 days. Fluconazole treatment was successful in 53% of the patients. In patients with proven or probable Candida albicans infections a clinical and mycological response was achieved in 62% and 65%, respectively. In 11 patients elevation of liver enzymes was considered to be possibly related to fluconazole treatment; modification of treatment was not necessary in any case. Fluconazole was found to be a well tolerated and effective agent for the treatment of systemic Candida albicans infections.

Adolescent↗
PubMed1992

Frequency domain analysis of highly amplified ECG on the basis of maximum entropy spectral estimation.

Recognition of patients with high risk for ventricular tachycardia (VT) or sudden cardiac death is of high clinical importance. We have investigated the efficiency of maximum entropy spectral estimation (MES) to detect such risk patients on the basis of highly amplified surface ECG. In comparison with the traditionally applied periodogram (fast Fourier transform), the MES produces sharper and more pronounced peaks in the power density spectrum (PS). The main problem is the influence of residual noise (after averaging), which often leads to additional components in the PS. To completely avoid this negative noise influence we developed a new algorithm, called the variance subtraction method. In a first clinical investigation 86 per cent of patients with myocardial infarction and ventricular tachycardia have shown frequency components above 80 Hz in the PS compared with healthy persons where no frequency components above this 80 Hz level could be detected.

Algorithms↗
PubMed1991

The metabolism of 7,10,13,16,19-docosapentaenoic acid to 4,7,10,13,16,19-docosahexaenoic acid in rat liver is independent of a 4-desaturase.

The hypothesis that the last step in the biosynthesis of 4,7,10,13,16,19-22:6 from linolenate is catalyzed by an acyl-CoA-dependent 4-desaturase has never been evaluated by direct experimentation. When rat liver microsomes were incubated with [1-14C]7,10,13,16,19-22:5, under conditions where linoleate was readily desaturated to 6,9,12-18:3, it was never possible to detect the product of the putative 4-desaturase. In the presence of malonyl-CoA, 7,10,13,16,19-22:5 was sequentially chain-elongated to 9,12,15,18,21-24:5, followed by its desaturation at position 6 to give 6,9,12,15,18,21-24:6. Microsomes desaturated 9,12,15,18,21-24:5 at rates similar to those observed for metabolizing linoleate to 6,9,12-18:3. Rat hepatocytes metabolize [1-14C]7,10,13,16,19-22:5 to 22:6(n-3), but in addition, it was possible to detect small amounts of esterified 24:5(n-3) and 24:6(n-3) in phospholipids, which is a finding consistent with their role as obligatory intermediates in 22:6(n-3) biosynthesis. When 3-14C-labeled 24:5(n-3) or 24:6(n-3) were incubated with hepatocytes, only a small amount of either substrate was esterified. [3-14C] 24:5(n-3) was metabolized both by beta-oxidation to 22:5(n-3) and by serving as a precursor for the biosynthesis of 24:6(n-3) and 22:6(n-3). The primary metabolic fate of [3-14C]24:6(n-3) was beta-oxidation to 22:6(n-3), followed by its acylation into membrane lipids. Our results thus document that 22:5(n-3) is the precursor for 22:6(n-3) but via a pathway that is independent of a 4-desaturase. This pathway involves the microsomal chain elongation of 22:5(n-3) to 24:5(n-3), followed by its desaturation to 24:6(n-3). This microsomal product is then metabolized, via beta-oxidation, to 22:6(n-3).

Animals↗
PubMed1991

[Automatic classification of the greatly amplified ECG in relation to time and frequency].

The non-invasive recording of cardiac micro-potentials from the surface of the body, in particular of the so-called ventricular late potentials from the highly amplified ECG, makes it possible to identify those patients at high risk from severe arrhythmics or sudden death. By using more extensive automatic parameter extraction methods, we were able to increase the detection rate of pathological ECGs. We were also able to show that the calculation of the power density spectrum, in particular on the basis of maximum entropy spectral estimation, in combination with the variance extraction method of eliminating the influence of residual noise, is capable of providing separate additional valuable information.

Arrhythmias, Cardiac↗
PubMed1991

[Correlation of endometric results with the conditions in the root canal].

The correlation of endometric measurements with physical indicators, such as electrode impedance, electrolyte conductivity, in canal geometry and measuring electrode insulation, seems to be secured by the coincidence between the results of experimental and theoretical calculations. The measuring principle on which the currently available endometric instruments operate, do offer the measuring accuracy required for clinical use.

Dental Pulp Cavity↗
PubMed1990

[Assessment of the risk of cardiovascular disease on the basis of total serum cholesterol in a population of young Danish women and men].

In this investigation the distribution of total cholesterol in the serum in a population of 364 medical students in the age group 22-32 years is assessed. The average value was 5.27 mmol/l for women and 5.08 mmol/l for men. 5% of the women and 2% of the men had values which exceeded 7.0 mmol/l and were thus in a group where treatment with diet or medicine may be considered, according to the recommendations from the Danish Association for Internal Medicine. In the group investigated here, the authors did not find any significant change in total cholesterol with age and, similarly, no significant seasonal variation was encountered.

Adult↗
PubMed1990

[Distribution of serum total cholesterol in a population with varying risks of cardiovascular disease].

By means of search in the literature and subsequent meta-analysis, the authors have described the serum total cholesterol values in three different risk groups for cardiovascular disease. High total serum cholesterol levels were associated with increased risk for cardiovascular disease. In addition, it was found that serum total cholesterol increases with age in all groups. A distinct sex difference was observed in the majority of investigations: in the age groups under 25 years and over 50 years, women have higher serum total cholesterol values than men while, in the age group 25-50 years, men have higher values than women. In addition, administration of hormones produces higher serum total cholesterol levels in young women but lower serum total levels among older women. In Danish investigations of serum total cholesterol, the level of serum total cholesterol corresponds to the serum total cholesterol levels in high and middle risk groups for cardiovascular disease.

Adolescent↗
PubMed1990

[SEM study of radiogenic caries].

The present SEH study could show that radiogenic caries is accompanied by morphological changes at the dentine-enamel junction. These changes appear as lacunar defects of up to 300 microns in size. This kind of defect was found in 28 of 32 teeth which were exposed to radiation of more than 40 Gy. In a control group with caries of the smooth surfaces no comparable results could be obtained.

Dental Caries↗
PubMed1990

[New electric techniques for root canal length measurement].

Reliable measurements of electrical resistance have recently been shown to be inaccurate for root canal length determination. By contrast, measuring differences in impedance allows impedance gradients to be recorded unaffected by electrode phenomena. Although technical problems concerning the application of the impedance gradient method have not yet been solved, mathematical, experimental and clinical findings show that root canal lengths can be reliably determined by this electrophysical method.

Dental Pulp Cavity↗
PubMed1990

[Chances for the intraoral use of screen films?].

The development of film/screen combinations has reached a point where they can be used intraorally for many indications. Compared with the fastest non-screen films the dose can be reduced by the factor 8, at the moment. For a wide-spread clinical usage, however, practicable application techniques still have to be developed for the intraoral film/screen combination.

Humans↗
PubMed1990

Assessment of in vivo activated T cells in patients with Crohn's disease.

Besides clinical indices, acute phase reactants and measurement of permeability of the gut immunological parameters have been proposed for assessment of clinical activity in Crohn's disease (CD). The latter refers in particular to the number of activated peripheral T cells (APT) which are found to be increased in patients with CD and ulcerative colitis. Further analysis of the subset of APT revealed that in CD their number is correlated to the histopathological ratings and the number of activated T cells of the affected mucosa. A major subset of APTs in CD and ulcerative colitis expresses receptors for IgA (Fc-alpha-R). This T cell subset seems to be characteristic of patients with inflammatory bowel diseases, exhibiting a specificity of 88% and a sensitivity of 92% for CD as compared with non-inflammatory bowel diseases. Methodological complexity turned out to be the major disadvantage of assessment of APT and their subsets.

Adolescent↗