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Biomedical subjects

K H Neumann

Publications and source records attributed to K H Neumann.

At least 37 records · Page 2Linked to original sources
PubMed1990

Ca2+ release in permeabilized human neutrophils induced by ciclosporin.

In suspensions of permeabilized human neutrophils, the free Ca2+ concentration was measured to test the effects of ciclosporin. Free Ca2+ concentration was measured with a Ca2(+)-selective electrode. Ciclosporin (500 ng/ml) induced a transient increase in free Ca2+ concentration (maximum delta pCa, 0.41 +/- 0.17). Thereafter, the free Ca2+ concentration decreased again, but did not reach the baseline level in most experiments. Ruthenium red, but not orthovanadate, abolished the slow decline of free Ca2+ concentration after the initial increase. The experiments suggest that ciclosporin may induce a release of Ca2+ from cellular organelles, e.g. the endoplasmic reticulum, and a partial reuptake in mitochondria. A release of cellular Ca2+ may play a role in ciclosporin-induced hypertension.

Calcium↗
PubMed1990

Correlation of free phenytoin to serum albumin in cancer patients.

The objectives of this study were to compare the total and free phenytoin serum concentrations of cancer patients with hypoalbuminemia with those of cancer patients with normal serum albumin and to correlate the percentage of free phenytoin with the albumin concentration. A total of 22 patients were studied, 13 with normal albumin concentration and 9 with low albumin. The mean free phenytoin in the normal albumin group was 9.9 (+/- 1.3) percent and 17.6 (+/- 4.6) percent in the low albumin group. With the groups combined, the mean free phenytoin was 13.1 percent (range 8.3-22.2) with the albumin range of 20-45 g/L. There was a significant negative correlation (r = -0.9, p less than 0.001) between the percentage of free phenytoin and the measured serum albumin. In cancer patients, the serum albumin concentration appears to be the key factor that determines the percentage of free phenytoin. In cancer patients with low serum albumin concentration, the total and free phenytoin concentration should be measured for adequate assessment of phenytoin therapy.

Female↗
PubMed1989

Amyloid goiter and arthritides after kidney transplantation in a patient with systemic amyloidosis and Muckle-Wells syndrome.

A case of hereditary AA amyloidosis with Muckle-Wells syndrome is described. After a successful kidney transplantation for chronic renal failure due to renal amyloid deposits at age 21, the patient, a white female now 26 years of age, developed a large amyloid goiter as a manifestation of the systemic amyloidosis and recurrent monarthritides. Both observations are novel for this disease. Subtotal thyroidectomy and oral colchicine administration, known to be effective in preventing complications of familial Mediterranean fever, another hereditary type of AA amyloidosis, proved highly effective in the management of this unusual case.

Adult↗
PubMed1986

Effective hydraulic permeability of the glomerular capillary wall in rats after uninephrectomy.

The effective hydraulic permeability (k) of glomerular capillaries was studied in 2-month-old Wistar rats 4 weeks after uninephrectomy in comparison to age-matched control rats. Isolated kidneys were perfused with a cell-free solution containing 5% albumin. In this preparation the rise of colloid osmotic pressure along the glomerular capillaries can be neglected because the filtration fraction is low (3%) due to high perfusion rates at normal filtration rates. Single nephron filtration rates (SNGFR) and effective filtration pressures were estimated by micropuncture to calculate the ultrafiltration coefficient (Kf). Glomerular capillary surface area was measured morphometrically to obtain k (k = Kf/S). We found that the effective hydraulic permeability in uninephrectomized rats was higher than in rats of comparable age (26.0 vs 18.0 nl/mm Hg X s X cm2). This can contribute to the adaptive rise in SNGFR after uninephrectomy.

Animals↗
PubMed1986

Influence of cyclosporine A on adaptive hypertrophy after unilateral nephrectomy in the rat.

The functional challenge to a transplanted kidney is comparable to that of a single kidney after unilateral nephrectomy. The single kidney model was used in rats to study the influence of the immunosuppressant CyA. Using this model interference with immunological or preservation/transplantation problems can be excluded. Two month old rats were studied 4 weeks after unilateral nephrectomy. After unilateral nephrectomy the juvenile rats had been fed for 28 days with 10 or 15 mg/kg BW CyA daily. These rats were compared to intact control rats and to age-matched uni-nephrectomized rats. Single kidney weight was measured in one group. Single kidney function was measured in a second group, first in the metabolic cage and then in experiments with isolated kidneys perfused under standard conditions. The glomerular filtration coefficient Kf was measured by micropuncture techniques. Glomerular capillary surface area was estimated after perfusion fixation in order to calculate the effective hydraulic permeability k of the glomerular capillary wall (k = Kf/S). Standard allogeneic skin transplantation across the MHC barrier was used to establish that the CyA dosage used was immunosuppressive. The results showed that the single kidney mass (as a measure of tubular hypertrophy) and GFR were suppressed under the influence of CyA compared to controls. Analysis of glomerular filtration parameters in the isolated perfused kidneys on the single nephron level had the following results: a small increase of the glomerular capillary surface (morphometry) was suppressed under CyA, whereas the effective hydraulic permeability (k) increased by almost 40% whether CyA was given or not.

Adaptation, Physiological↗
PubMed1986

Erythromycin ototoxicity and acute psychotic reaction in cancer patients with hepatic dysfunction.

Two cases of severe hearing loss due to intravenous administration of erythromycin lactobionate are described. Documented, bilateral sensorineuronal hearing loss developed in both patients and gradually improved when the dose of erythromycin was decreased. Neither patient had severe renal dysfunction (documented clearances of 25 to 30 mL/min), but both had hepatic dysfunction with elevated bilirubin levels. Additionally, both were receiving other ototoxic drugs concurrently. Both patients also had an acute psychotic reaction that was temporally related to the ototoxicity and high-dose erythromycin therapy.

Aged↗
PubMed1984

Chloride-induced increase of plasma potassium after transfusion of erythrocytes in dialysis patients.

The transfusion of packed red cells (PRC), though they are depleted in cellular potassium, is thought to result in an increase of serum potassium when transfused to patients on regular hemodialysis treatment. The aim of this study was to prove this hypothesis when transfusion was performed during the dialysis-free interval. The effect of 21 transfusions of 2 units of PRC once washed with 0.9% NaCl was analyzed in 10 anemic patients. A significant increase of plasma potassium from 5.5 to 5.9 mmol/l was observed. Intracellular sodium and potassium after transfusion reflected a mixing of the patients' endogenous and the transfused red cells. However, the excess of cellular chloride introduced by the washing procedure, which was by 27.6 mmol/l higher in the transfused cells, could not be detected in the mixed cell population after transfusion. The rapid chloride shift from the transfused acid red cells into plasma, which is accompanied by a rapid uptake of bicarbonate, is thought to release an equivalent amount of potassium, most likely from muscle or bone and enhances plasma potassium. Transfusion of PRC in the dialysis-free interval seems to be no risk for patients with a plasma potassium below 5 mmol/l. Alternatives are transfusion during dialysis or addition of 20 mmol sodium bicarbonate, when transfusion is performed in the dialysis-free interval.

Adult↗
PubMed1984

Glomerular albumin leakage and morphology after neutralization of polyanions. I. Albumin clearance and sieving coefficient in the isolated perfused rat kidney.

In order to decide whether foot process abnormalities in nephrotic states are the cause or the consequence of proteinuria, the polycation protamine has been applied to isolated perfused rat kidneys and functional parameters and morphology have been compared. With 110 micrograms/ml protamine the albumin clearance ratio increased from 2.0 +/- 0.7 x 10(-3) in controls to 14.8 +/- 6.9 x 10(-3) 10-20 min after application and even to 98.0 +/- 30.8 x 10(-3) after 50-80 min. Micropuncture samples collected from early proximal tubules with pressure control were used to calculate the sieving coefficient which correlated with albumin clearance ratios (controls: 1.8 +/- 1.0 x 10(-3); after 10-20 min: 11.8 +/- 6.4 x 10(-3); after 50-80 min: 52.0 +/- 8.5 x 10(-3). Glomerular filtration rate decreased in the early beginning from 1.1 +/- 0.2 ml x min-1 x g-1 kidney to 0.7 +/- 0.2 ml x min-1 x g-1 kidney, but remained constant throughout the whole experiment. Despite the markedly increased albuminuria there were no changes in glomerular foot process morphology with the protamine dose used.

Albumins↗
PubMed1980

Investigations on ploidy levels of haploid and diploid callus and cell suspension cultures of Datura innoxia Mill.

Using haploid and diploid Datura innoxia Mill, callus cultures and cell suspensions it was shown that meristematic material usually attains the lowest possible C-value of a given ploidy level. Parenchyma material of callus cultures, however, indicates a broad scattering of C-values up to 16 C, which is paralleled by C-value distribution of the free cell fraction in actively dividing cell suspensions. In these suspensions, cell division activity seems to be restricted to small meristem-like clusters.

Cell Cycle↗
PubMed1980

[Studies of a family with hereditary elliptocytosis].

In a 35 years-old patient the diagnosis of anaemia with elliptocytosis was made, and the family of this patient studied. In 5 of total 16 probands elliptocytes in the peripheral blood were found. Only in one case there was a haemolytic anaemia with an enlarged spleen. Splenectomy led to clinical healing.

Adolescent↗
PubMed1980

A notable Aspergillus from a mortal aspergilloma of the lung. New aspects of the epidemiology, serodiagnosis and taxonomy of Aspergillus fumigatus.

Different basic mycological observations were made in relation to a fatal case of aspergilloma of the lung in a 45-year-old male. Cultural examination of the sputum and autopsy material from the lung revealed the predominant presence of a white fungus along with a scarce growth of the typical Aspergillus fumigatus. The white isolate produced conidial heads almost similar to that of A. fumigatus but with apparent septation in the phialides. With the help of the immunodiffusion test and use of the antigens from the typical A. fumigatus strain and from the white isolate, antibodies could be detected in the serum of this patient and an antigenetic relationship between these fungi could be observed. It is assumed that this white isolate is a variant of A. fumigatus and its presence in the lung is an indication of chronic or progressed aspergillosis caused by A. fumigatus. Cultural characteristics and developmental morphology of this fungus and the serodiagnostic value of the antigen derived from it will be described in detail in separate communications.

Antibodies, Fungal↗
PubMed1978

The nucleotide sequence of the 5' untranslated region of human gamma-globin mRNA.

The nucleotide sequence of the entire 5' untranslated region of human gamma-globin mRNA has been determined. This was accomplished by analyzing complementary DNA (cRNA) synthesized from the mRNA with reverse transcriptase. The CDNA was labeled at its 3' end with 32"p using terminal deoxynucleotidyl transferase, digested with the restriction endonuclease Hae III and the end-labeled fragment isolated ans sequenced by the method of Maxam and Gilbert. Including the initiation codon AUG, the 5' untranslated region of human gamma-globin mRNA contains 57 nucleotides, compared to 41 in alpha- and 54 in beta-globin mRNA. There is very little homology between alpha and gamma sequences in the 5' region. There is considerable homology between beta- and gamma-globin mRNAs in the regions proximal and distal to the initiation codon, but the entire sequence shows less homology than the human and rabbit beta-globin mRNAs. The hexanucleotide sequence CUUCUG is found near the 5' ends of all three human globin mRNAs, suggesting a possible role of this sequence or ribosomal binding. Both guanosine and cytidine were found at the 19th nucleotide position from the 5' end of the gamma mRNA. We believe this heterogeneity arises from the difference in nucleotide sequence between the A gamma and G gamma loci.

Base Sequence↗
PubMed1977

The nucleotide sequences of the untranslated 5' regions of human alpha- and beta-globin mRNAs.

The complete sequences of the untranslated 5' regions of human alpha- and beta-globin mRNAs were determined by sequence analysis of full-length cDNAs. The single-stranded cDNAs were digested with the restriction endonuclease Hae III, and the two 3'-terminal fragments of 75 and 132 nucleotides, complementary to the 5' termini of the alpha- and beta-globin mRNAs, respectively, were isolated and sequenced. Including the initiation codon AUG, the untranslated 5' regions of human alpha- and beta-globin mRNAs contain 41 and 54 nucleotides, respectively, and exhibit striking homologies with the corresponding sequences in the rabbit. Human alpha- and beta-globin mRNAs have five bases in the region of the initiation codon that may form base pairs with the 3' terminus of 18S rRNA. Stable secondary structures with hairpin loops can be constructed in the untranslated 5' regions.

Base Sequence↗
PubMed1976

Mechanism of NaCl and water reabsorption in the proximal convoluted tubule of rat kidney.

The role of chloride concentration gradients in proximal NaCl and water reabsorption was examined in superficial proximal tubules of the rat by using perfusion and collection techniques. Reabsorptive rates (Jv), chloride concentrations, and transtubular potential difference were measured during perfusion with solutions (A) simulating an ultrafiltrate of plasma; (B) similar to (A) except that 20 meq/liter bicarbonate was replaced with acetate; (C) resembling late proximal fluid (glucose, amino acid, acetate-free, low bicarbonate, and high chloride); and (D) in which glucose and amino acids were replaced with raffinose and bicarbonate was partially replaced by poorly reabsorbable anions (cyclamate,sulfate, and methyl sulfate). In tubules perfused with solutions A and B, Jv were 2.17 and 2.7 nl mm-1 min-1 and chloride concentrations were 131.5 +/- 3.1 and 135 +/- 395 meq/liter, respectively, indicating that reabsorption is qualitatively similar to free-flow conditions and that acetate adequately replaces bicarbonate. With solution C, Jv was 2.10 nl mm-1 min-1 and potential difference was +1.5 +/- 0.2 mV, indicating that the combined presence of glucose, alanine, acetate, and bicarbonate per se is not an absolute requirement. Fluid reabsorption was virtually abolished when tubules were perfused with D solutions; Jv was not significantly different from zero despite sodium and chloride concentrations similar to plasma; chloride concentration was 110.8 +/- 0.2 meq/liter and potential difference was -0.98 mV indicating that chloride was close to electrochemical equilibrium. These results suggest the importance of the chloride gradient to proximal tubule reabsorption in regions where actively reabsorbable solutes (glucose, alanine, acetate, and bicarbonate) are lacking and provide further evidence for a passive model of NaCl and water transport.

Absorption↗