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Biomedical subjects

B Neubauer

Publications and source records attributed to B Neubauer.

16 recordsLinked to original sources
PubMed1992

Erythrocyte pyruvate kinase deficiency: relations of residual enzyme activity, altered regulation of defective enzymes and concentrations of high-energy phosphates with the severity of clinical manifestation.

The defective enzymes of 54 patients with pyruvate kinase (PK) deficiency were characterized according to the recommendations of the International Committee for Standardization in Haematology (ICSH). The erythrocyte PK activity in whole blood was calculated considering the 16-fold higher activity of the reticulocyte enzyme (AR) compared to the erythrocyte enzyme (AE). The following parameters turned out to give a good correlation to the degree of haemolytic anaemia and can therefore serve as a prognostic tool: All patients with a severe course of the disease had residual erythrocyte PK activities less than 33% of the normal enzymes (percentage activity), and patients with mild haemolytic anaemia exhibited residual activity values below and above this threshold value. Studies of enzyme cooperative showed that positive cooperative or mixed cooperative phosphoenolpyruvate (PEP) binding with a predominant positive cooperative part appeared in all cases with a mild clinical course, and about one-third of the severe ones. Negative cooperativity or mixed cooperativity with predominant negative cooperative part was observed only with severe haemolytic anaemia. Furthermore, the determination of glucose-6-phosphate (G-6-P) turned out to be a good prognostic criterion, i.e. all patients with mild clinical course exhibited G-6-P-concentrations lower than 0.11 mumol/l red blood cells. In the case of patients with severe haemolytic anaemia, about 80% showed values higher than 0.11 mumol/l RBC.

2,3-Diphosphoglycerate↗
PubMed1992

Analysis of gene amplification in archival tissue by differential polymerase chain reaction.

Oncogene amplification is found in many human tumors, and its detection may have important prognostic value. However, analysis of gene amplification may be hampered by inadequate tissue or poor DNA quality. We have previously described a polymerase chain reaction (PCR)-based procedure called differential PCR that can detect variations in gene dosage using miniscule amounts of tumor DNA [Frye, R.A., Benz, C.C. & Liu, E. (1989). Oncogene, 4, 1153-1157]. We now report the optimization of this technique for the analysis of oncogene amplification in paraffin-embedded archival tissues. We find that differential PCR is able to detect amplification of the HER2 (c-erbB-2) and the epidermal growth factor receptor (EGFR) genes and can be used to arrive at a semiquantitative estimate of gene dosage. Furthermore, our approach can determine gene amplification in samples in which the DNA is significantly degraded. Using differential PCR on paraffin-embedded tissues from cases previously investigated by standard DNA extraction and dot-blot procedures, good correlation between the two methods was found. Approaches are described to overcome technical problems posed by factors that affect the differential PCR, including the method of DNA extraction and extreme fragmentation of the DNA (less than 200 base pairs). Furthermore, the resulting analytical algorithm reported herein has proved effective in detecting oncogene amplification in archival breast cancer specimens from standard pathology laboratories. Thus, differential PCR will be particularly helpful in the analysis of tumor specimens that are archived, small in size or rare in occurrence.

Algorithms↗
PubMed1991

Point mutations in the L-type pyruvate kinase gene of two children with hemolytic anemia caused by pyruvate kinase deficiency.

The molecular alterations responsible for the characteristic enzyme abnormalities in pyruvate kinase (PK) deficiency were investigated in two unrelated children homozygous for PK deficiency. Both variant enzymes were characterized according to the recommendations of the International Committee for Standardization in Haematology. Genomic DNA was specifically amplified by the polymerase chain reaction. Normal and mutant alleles of the L-type PK gene were analyzed by nucleotide sequencing. Heterozygosity of the parents was confirmed by allele-specific oligonucleotide hybridization. In PK Linz a C to T base exchange at position 394 of the L-type PK gene was found. As a result, the 132nd amino acid of the mutant enzyme, arginine (CGC), is replaced by cysteine (TGC). The affected amino acid residue is located within the deduced active site of the protein and the enzyme variant shows strongly altered allosteric properties. PK Beirut shows a C for T substitution at position 1058, changing the 353 amino acid from threonine (ACG) to methionine (ATG). In contrast to PK Linz, this amino acid lies outside the deduced substrate binding site and kinetic parameters of PK Beirut are close to normal. Both enzyme variants show a markedly reduced specific activity and thermolability.

Anemia, Hemolytic↗
PubMed1991

[Normal wall thickness and neoplastic wall changes in the gastrointestinal tract as shown by computed tomography].

55 patients with tumours of the gastrointestinal tract were examined by CT, using a paraffin emulsion as a negative oral contrast medium. These were compared with 119 normal patients. The appearance of normal and tumour bearing portions of the gut wall against the contrast medium was studied. Under hypotonic conditions the gut wall could regularly be distinguished from surrounding organs and gut content. Mural thickness of the oesophagus greater than 7 mm and of the stomach and colon greater than 8 mm must be regarded as abnormal. Benign diseases cannot be distinguished from malignant conditions on the basis of wall thickness. Artifacts, such as are caused by positive oral contrast, were of less significance when using paraffin emulsion.

Adult↗
PubMed1990

Polymerase chain reaction based assay to detect allelic loss in human DNA: loss of beta-interferon gene in chronic myelogenous leukemia.

We have developed a polymerase chain reaction (PCR) based technique to detect allelic loss. In this differential PCR a target gene and a reference gene are coamplified in the same reaction vessel. The ratio of the intensity of the two resultant bands is an indication of relative gene dosage. This procedure is sensitive in that gene copy ratios of 2:1 and 3:2 (reference: target gene) can readily be detected. Using this differential PCR, we have examined 64 cases of chronic myelogenous leukemia (CML) for the loss of the beta 1-interferon gene, a relatively common event in certain human leukemias and lymphomas. Only one patient who was Philadelphia chromosome positive and who was in blast crisis exhibited allelic loss of the beta-interferon gene. Thus despite deletions at the beta-interferon locus in the CML cell line, K562, this perturbation is rarely seen in primary CML samples.

Alleles↗
PubMed1989

[Application of the 6-day subrenal capsule assay for sensitivity testing of antineoplastic chemotherapy in oral mucosa carcinoma].

Tissues from squamous cell carcinomas of the oral cavity of 20 patients were transplanted beneath the capsule of the kidney of normal immunocompetent mice (SRCA). The xenografts of all tumors of the control group of animals without chemotherapy show an increasing tumor mass following a 6-day-test-period using a method of measurement given by Bogden et al. (1978). There were different changes of tumor diameters following the application of various antineoplastic drugs. Tumor proliferation however is not reason for these changes. There are reactions of graft's rejection which play an important part in the measured data. The only interpretation of the diameters of the xenografts using the 6-day-SRCA in normal immunocompetent mice cannot be recommended as a criterion in this predictive test.

Animals↗
PubMed1978

Analysis of heart rate variations in patients with multiple sclerosis. A simple measure of autonomic nervous disturbances using an ordinary ECG.

A simple method requiring only an ordinary ECG apparatus and a ruler has shown a hitherto unknown abnormality of the autonomic nervous sysyem in patients with multiple sclerosis. The main findings were that both long-term and short-term variations in heart rate were reduced in patients wirh multiple sclerosis. The reduction was comparable with that observed in other patients with autonomic abnormalities-for example, long-term diabetics-but in addition patients with multiple sclerosis presented unexpected large shifts in pulse rate levels, lasting from a few to 10 or 20 beats.

Adult↗
PubMed1978

The decrease in noradrenaline concentration in the posterior tibial artery with age.

The concentrations of noradrenaline and adrenaline were studied in specimens of the posterior tibial artery obtained from 18 subjects at postmortem examination. The mean noradrenaline concentration was 167 ng/g artery (range 17-449 ng/g) and the mean adrenaline concentration was 5 ng/g (range 0--21 ng/g). There was no difference in noradrenaline and adrenaline concentrations expressed in ng/g between male and female subjects. Expressed in ng/cm artery the arterial noradrenaline concentration was insignificantly lower in the females than in the males. The arterial noradrenaline concentration decreased considerably with age and to the same extent in both sexes.

Adult↗
PubMed1978

Intraarterial tolazoline in angiography of the foot.

Foot angiography was performed in 32 diabetic patients with and without intraarterial injection of tolazoline (Priscoline). The angiographic quality was improved with tolazoline, manifested as an increased flow rate with acceleration of the arteriovenous transit time, a higher incidence of complete arterial filling with contrast medium in clinically important regions, and considerably longer arterial segments demonstrated within defined regions of measurement.

Adult↗
PubMed1977

A long-term diabetic autonomic nervous abnormality. Reduced variations in resting heart rate measured by a simple and sensitive method.

Three types of variation in resting pulse rate were measured, using simple and reproducible methods, in 44 young juvenile diabetics and 11 controls. Diabetics with few years duration of the disease showed normal values of both long-term and cyclic fluctuations, as well as of non-systematic, random variation from beat-to-beat. All three types of variation were reduced in long-term diabetics, and the reduction was in all cases correlated with the duration of diabetes. The decrease in non-systematic, beat-to-beat variation attained statistical significance after 5 to 10 years duration of diabetes. It is concluded that reduced variation in resting pulse rate is a long-term diabetic manifestation and that the decrease of non-systematic, beat-to-beat variations in diabetics is a useful indicator of functional abnormalities of the autonomic nervous system.

Adult↗
PubMed1977

Tilted and non-tilted postischaemic exercise peak flow in the legs of normal human subjects.

Peak flow was measured by radioactive xenon in fifteen normal subjects in the anterior tibial muscle after maximal ischaemic exercise. The postischaemic exercise peak flow was 75 +/- 13 ml/100 g muscle/min (mean +/- SD), when the test was performed while the subjects rested in the horizontal position. When the same test was performed with the subjects resting in a 45 degrees feet down tilted position, the peak flow increased very much, about 65%, and averaged 125 +/- 17 ml/100 g muscle/min. The increased peak flow in the feet tilted position is explained by passive dilatation of the vessels due to increased hydrostatic pressure. It is suggested, that measurement of maximal ischaemic exercise blood flow in the tilted position may be a more sensitive procedure for detection of minimal vascular changes due to the very high blood flow obtained.

Adult↗
PubMed1976

Adrenaline in the human pancreas.

The present study describes the results of examinations of the noradrenaline and adrenaline concentrations in the human pancreas as well as in a number of other organs. Tissue specimens were obtained at post-mortem examination. Adrenaline was present in small amounts in the cardiovascular system, the liver and the spleen in comparison with the noradrenaline concentration. The pancreas, especially the body of the pancreas, contained, however, considerable amounts of adrenaline. The average adrenaline concentration was approximately 20 times higher in the pancreas than in the other organs examined. The greatest concentration of adrenaline was found in the posterior and superior parts of the body of the pancreas. There was no relationship between the cause of death in the human subjects and the adrenaline concentration in the pancreas and large amounts of adrenaline were also found in tissue specimens of pancreas obtained from long-term diabetic patients. Adrenaline was present in the pancreas of the rat, dog and rabbit but in small amounts in comparison with the noradrenaline concentration.

Adult↗
PubMed1976

Norepinephrine, epinephrine, and dopamine contents of the cardiovascular system in long-term diabetics.

Norepinephrine, epinephrine, and dopamine concentrations were studied in the cardiovscular system of postmortem material obtained from six long-term diabetics and six control subjects. Norepinephrine concentration was considerably reduced in the cardiovascular system of the diabetic patients. The mean norepinephrine concentration in the apex of the heart, the radial artery, the posterior tibial artery, and the femoral artery in the diabetics averaged 6, 9, 12, and 20 per cent, respectively, of the corresponding mean values in the controls. Epinephrine was present in the cardiovascular system in the controls but in small amounts in comparision with norepinephrine. There was no correlation between the epinephrine and the norepinephrine concentrations in the tissue. In the diabetics the epinephrine concentration in the heart and in the arteries did not differ from the values obtained in the controls. The dopamine concentration averaged 11 per cent of the norepinephrine concentration in the cardiovascular system in the controls. There was a strong correlation between tissue concentrations of dopamine and of norepinephrine. In the diabetics the dopamine concentration was reduced, but relatively less than that of norepinephrine, and constituted 53 per cent of the norepinephrine concentration. It is suggested that the depletion of the norepinephrine stores in the heart in diabetic patients may in part be responsible for their reduced survival rate in acute myocardial infarction.

Adult↗