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Biomedical subjects

K Günther

Publications and source records attributed to K Günther.

At least 91 records · Page 5Linked to original sources
PubMed1991

Investigations of cerebral glucose utilization into the newborn brain: a [18F]-FDG positron emission tomography study using a high resolution multiwire proportional chamber detector device.

An experimental approach is presented, where for the first time positron emission tomography (PET, the most important method for in vivo measuring the key functions of brain physiology and metabolism) was applied together with other techniques for quantitative-topological estimation of key parameters such as rCMRGlu in normal and disturbed brain function states in the newborn period.

Animals↗
PubMed1991

Mode of action of triethylenetetramine dihydrochloride on copper metabolism in Wilson's disease.

The drug of choice for the initial treatment of "decoppering" in Wilson's disease, an inherited disorder of copper metabolism, is the chelating agent D-penicillamine. In the case of harmful side-effects an alternative drug is triethylenetetramine dihydrocholoride (trien or trientine). Using the 24-h-urine excretion of copper and the oral copper loading test with copper-64, a double function for trien was found: trien increases the urine copper excretion and decreases the intestinal copper absorption respectively.

Adult↗
PubMed1991

[Effect of the ACE-inhibitor captopril on the blood pressure and kidney function of patients with essential and renal hypertension].

We retrospectively analysed the effects of a 12-month treatment with captopril (Tensiomin) in 46 patients. All of the patients had hypertension lasting for years (9 essential, 37 with chronic renal failure), 32 of them had proteinuria. Captopril was given in addition to, or in exchange for, other antihypertensive drugs. Under treatment with ACE-inhibitors, a small but significant decrease in diastolic blood pressure (0.4 torr/month) and in proteinuria (0.19 g/month) was seen (regression analysis). Discriminant analysis showed proteinuria and diastolic blood pressure to be the more modifiable, the younger the patients, the higher the proteinuria at the beginning and the longer the history of hypertension. Serum creatinine, blood urea nitrogen, serum protein and serum potassium did not change.

Adult↗
PubMed1990

Hypoxic dilation of coronary arteries is mediated by ATP-sensitive potassium channels.

The function of the heart depends critically on an adequate oxygen supply through the coronary arteries. Coronary arteries dilate when the intravascular oxygen tension decreases. Hypoxic vasodilation in isolated, perfused guinea pig hearts can be prevented by glibenclamide, a blocker of adenosine triphosphate (ATP)-sensitive potassium channels, and can be mimicked by cromakalim, which opens ATP-sensitive potassium channels. Opening of potassium channels in coronary smooth muscle cells and the subsequent drop in intracellular calcium is probably the major cause of hypoxic and ischemic vasodilation in the mammalian heart.

Adenosine Triphosphate↗
PubMed1990

[Biochemistry of cellular radiation reactions. An indication for ongoing protective mechanisms against oxidative cell damage].

Cellular radiation, which is the constant low-level photon emission in animal and plant tissue, is due to particular reactions of metabolism producing ultraweak chemiluminescence. A possible effect of the cellular radiation is the activation of DNA photolyases. In most chemiluminescent processes reactive oxygen metabolites are transformed. When these reactions occur in the cytosol they help to protect vital cell structures against oxidative damage.

Animals↗
PubMed1990

Simultaneous multielement determination in vegetable foodstuffs and their respective cell fractions by total-reflection X-ray fluorescence (TXRF).

Total-reflection X-ray fluorescence (TXRF) was employed in the multielement determination made on samples of lamb's lettuce and cauliflower as well as in the analysis of their soluble and insoluble cell fractions. All samples were digested with HNO3 and the elements were quantitatively determined with Ga as internal standard. For cell fractionation, the freeze-dried vegetables were mortared in the presence of fine-grain quartz and extracted with a buffer solution; the resulting suspension was then separated by ultracentrifugation into cytosol and pellet components. K, Ca, Mn, Fe, Cu, Zn, Rb and Sr were the elements of which the total content and distribution between cytosol and pellet were determined. As a result of the cellular digestion and extraction procedures employed, greater than or equal to 50% of the total metal contents of Zn, Cu, K and Rb could be reduced to the cytosol phase in both vegetables, however, Sr, Fe, Ca and Mn were mainly bound to the insoluble pellet components which, in the case of cauliflower, contained up to 100% of the total Sr content. As a multielement method, TXRF proved to be an excellent analytical tool in these investigations, since it requires only minute samples with simple preparation and involves a large dynamic measuring scale.

Calcium↗
PubMed1990

[In vitro studies of the adsorption behavior of Wofatit Y 88 in relation to various drugs].

The adsorber Wofatit Y 88 (VEB Chemiekombinat Bitterfeld) was tested regarding its adsorption properties in comparison with Hämoresin (B. Braun, Melsungen, FRG) Hemosorbent SKN-2K (USSR) and the own product Wofatit UH 91. As adsorptives the hypnotics Metaqualon, Pyrithyldion, Crotylbarbital and Phenobarbital were used. The investigation have been performed in a single-pass system in a relation of 1:25 to the clinical practice conditions. The concentration measurements to the estimation of adsorbed amounts were made by UV-VIS spectrometry. It was found that Wofatit Y 88 is superior to Hämoresin with regard to adsorbed amounts and adsorption speed. For all drugs Wofatit Y 88 was superior to UH 91.

Adsorption↗
PubMed1990

[Wilson's disease in East Germany: in retrospect and perspectives -- an evaluation].

Wilson's disease is an autosomal recessive inherited metabolic disorder due to a disturbance of copper metabolism. Although the primary genetic defect is not known a longlife treatment is necessary for establishing a negative copper balance by removing the metal of the abnormal body stores. Experiences in handling with this disease in our country over a period of 20 years are reported. Especially epidemiologic findings, the diagnostic procedures and the strategies in therapeutic regimes are discussed. Future advances in genomic diagnostics are mentioned.

Adolescent↗
PubMed1990

[Use of calcium carbonate (CaCO3) as phosphate binder in dialysis patients in long-term follow-up over 3 years].

In 26 dialysis patients (age 46 +/- 47.8 years, dialysis 20.1 +/- 57 months) calcium carbonate was introduced to phosphate reduction for 3 years. The use of CaCO3 (4.4-9 g/d) for 9 months did reduce the phosphate level from 2.51 to 1.51 mmol/l in 77% of the patients and increase the calcium from 2.23 to 2.47 mmol/l. The long-term use use up to 3 years did'nt reduce the phosphate level effectively (mean value 2.24 mmol/l). In 77% of the patients a progression and in 42% new calcifications could be observed. The percentage of patients with soft tissue calcification within the 3-year CaCO3 therapy was increased from 43% to 67%. Therefore, CaCO3 alone in unsuitable for long-term use as phosphate binder in dialysis patients.

Aluminum↗
PubMed1990

[Patients born in autumn more frequently develop atopic eczema].

Data of birth from 4040 atopic dermatitis patients born in the Berlin area were analyzed in view of their distribution over the 12 months of the year. For comparison the data of birth of all people being born during two years were treated the same way. There was a marked increase of atopic dermatitis with the persons born during the months August to October. On the other hand, the prevalence of atopic dermatitis was diminished with that persons who were born from February till July (with exception of May). Obviously, during the first months of life seasonally differing external factors influence directly o indirectly the decision, whether atopic dermatitis later on will manifest or not. These results should been taken into consideration for family planning in high-risk families.

Adolescent↗
PubMed1989

[Clinical significance of beta 2 microglobulin determination in dialysis patients].

In radioimmunological estimation of beta 2-microglobulin significant higher serum values were found in 36 dialysis patients (44.4 +/- 20.3 mg/l) in comparison with healthy probands (1.5 +/- 0.2 mg/l). A significant relation to the duration of dialysis, rest diuresis and serum level of aluminium was found. Significant higher concentrations were observed in patients suffering from pain in the shoulder-limb-region and with ostealgia in other regions, but not in radiological verified destructive arthropathy and spondylarthropathy. The used dialyzers MLW 1.3/1.8 m2 did not eliminate the beta 2-microglobulin from the blood.

Adult↗
PubMed1988

Thin-layer chromatographic enantiomeric resolution via ligand exchange.

A thin-layer chromatographic technique for the separation of proteinogenic and non-proteinogenic amino acids, dipeptides and alpha-hydroxy acids is described. Other examples are given from the field of alpha-methyl, N-alkyl and halogenated amino acids. The separation of the enantiomers is achieved, without derivatization, by means of ligand exchange on a reversed-phase silica gel as stationary phase, which is covered with a chiral selector (proline derivative). The resolution is so good that the respective enantiomers can be determined at trace levels (greater than or equal to 0.25%). The proposed method is simple, inexpensive and needs no sophisticated instruments.

Amino Acids↗
PubMed1988

Suppression of the btuB451 mutation by mutations in the tonB gene suggests a direct interaction between TonB and TonB-dependent receptor proteins in the outer membrane of Escherichia coli.

In cells of Escherichia coli, the function of the tonB gene is needed for energy-dependent transport processes mediated by the outer-membrane receptors for iron siderophore complexes and vitamin B12. The btuB451 mutation has the same effect on vitamin B12 transport as does a tonB mutation. When a btuB451 strain carried a plasmid with the intact tonB gene, partial revertant strains were isolated which had acquired the ability to grow on 5 nM vitamin B12. This suppression activity was associated with the plasmid, suggesting that a mutation within the tonB gene on the plasmid allowed the mutant BtuB receptor to function in the transport of the vitamin. The nucleotide sequence of the entire tonB gene of ten independently isolated suppressing plasmids was determined. Only a single nucleotide change had occurred in each of the cases. The same codon was always affected resulting in the conversion of glutamine-165 to a leucine in seven of the ten isolates and to a lysine in the other three. The phenotype of strains carrying both types of altered tonB genes showed the retention of their function for other TonB-dependent processes in addition to their suppressor properties with respect to the btuB451 mutation. The fact that mutations suppressing the btuB451 mutation occurred in the tonB gene suggests that there is a direct interaction between TonB and TonB-dependent receptors in the outer membrane of E. coli.

Amino Acid Sequence↗
PubMed1988

Vitamin status in patients with chronic renal failure.

Many factors complicate the effort for a recommendation on individual vitamin requirements in CRF. On the basis of our present incomplete knowledge about the handling of vitamins in uremia, suggestions for appropriate supplementation only of water-soluble vitamins are given. Patients with advanced CRF without dialysis treatment should receive daily supplements of vitamin B6 (5 mg), ascorbic acid (70-100 mg), and the normal recommended daily allowance of the other water-soluble vitamins in addition to the vitamin intake from the diet. We give folic acid only in patients taking antifolate drugs or in combination with iron in iron deficiency state and anemia (1 tablet of Folicombin contains 0.5 mg folic acid and 0.4 g elemental iron). There is still a pressing need for more data on the vitamin status, on vitamin requirements, and on long-term effects of vitamin administration in CRF.

Humans↗
PubMed1988

[Changes in the pharmacokinetics of gentamycin during nephrotoxic therapy].

Nephrotoxicity secondary to aminoglycoside antibiotic therapy is a well-known complication in clinical medicine. We have analysed the influence of a 10-day gentamicin treatment with 3.40 mg/d on pharmacokinetic parameters and renal excretion of electrolyses and beta-NAG in 10 patients (9 female, 1 males) with UTJ. Using compartment-independent methods the following kinetic parameters at the first and 10th day of treatment were estimated: total body clearance from 100 to 80 ml/min (-20%), mean residence time from 2.7 to 3.5 h (+28%) and AUC from 6.7 to 9.4 mg/l.h (+41%). Similar results could be obtained using a linear two-compartment model: k13 is changed from 0.74 to 0.54 h-1 (-27%). Vdss approximately 16 1, k12 and k21 are not significantly influenced. There was no significant difference between the first and 10th day for renal excretion electrolyses, urine volume and osmolality with the exception of beta-NAG, which increased from 7.2 to 11.7 U/l (p less than 0.05). From the results it can be concluded that even a ten day gentamicin treatment with normal doses and serum concentrations in the therapeutic range less than 5 mg/l induce nephrotoxic effects at the glomerular and tubular side of the nephron. For quantification of the nephrotoxic effects we propose a nonlinear two-compartment model with a new pharmacokinetic parameter for renal damage. This new model allows to predict and to compare the nephrotoxic effects for different aminoglycoside antibiotics and different modes of treatment.

Electrolytes↗
PubMed1988

[Disordered postoperative course. A retrospective analysis].

A brief definition of the term of "relaparotomy" is followed by reference to some causes of erroneous or delayed decisionmaking on re-operation. The background of postoperative disorders is, basically, one and the same throughout acute surgery: haemorrhage, peritonitis, ileus. Relaparotomy was necessary in 0.6 per cent of the authors' cases, in the course of five years. Lethality amounted to 31 per cent at an average age of 50 years. Colorectal carcinoma was the most common cause of relaparotomy, with ileus of the small intestine being the most important of all indications. The average intervals between primary surgery and relaparotomy were seven days for ileus, 3.5 days for peritonitis, and up to 24 hours for postoperative bleeding. A lethality analysis after the first operation showed that only two of 96 deaths were attributable to omission of relaparotomy. Finally, reference is made to some clinical peculiarities in postoperative developments as well as to evaluation and interpretation of paraclinical data.

Abdomen↗
PubMed1987

Pharmacokinetics and pharmacodynamics of high dose furosemide in patients with chronic renal failure or nephrotic syndrome.

The pharmacokinetics and pharmacodynamics of repeated oral administration of furosemide were studied in patients with chronic renal failure or nephrotic syndrome using three different dosage regimens (4 x 40, 4 x 80 and 4 x 250 mg/d). Concentrations of the unchanged drug in serum and urine were measured fluorometrically. The elimination kinetics of furosemide was linear over the dose range studied. In contrast, the bioavailability of this diuretic decreased with increasing doses. The diuretic effects of all three dosage regimens were distinct only on the first day of therapy, thereafter decreasing rapidly. It can be concluded that the hormonal regulation of water and electrolyte balance are responsible for this behavior rather than pharmacokinetics. Creatinine and urea nitrogen excretion were not influenced by any furosemide dosage regimen.

Adult↗