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Biomedical subjects

A Albert

Publications and source records attributed to A Albert.

At least 289 records · Page 16Linked to original sources
PubMed1980

[Prenatal diagnosis in parents with a balanced structural chromosome aberration (author's transl)].

By means of 10 case reports, the significance of prenatal diagnosis and the risk for the progeny of parents with a balanced structural chromosomal aberration are demonstrated. The aberrations were ascertained through: a previous malformed child, previous miscarriages or stillbirths or through fetal cell analysis during prenatal diagnosis performed for independent reasons. Theoretical considerations concerning the estimates of risk figures in these families are presented and the currently available risk values which are the basis of the indication for prenatal diagnosis, given.

Adult↗
PubMed1980

The radioprotective effect of misonidazole (Ro-07-0582) on normal canine rectum.

A single 1500 rad (=15 Gy) dose of 10-MeV X-rays was administered to the pelvis of 20 mongrel dogs. Ten received misonidazole (Ro-07-0582), 100 mg/kg p.o., 4 hours pre-irradiation. Serum misonidazole levels immediately pre-irradiation were 43 +/- 10 microgram/ml (mean +/- SD). The dogs were euthanized within 3 months post-irradiation. Each rectal specimen was studied for anatomic and histologic pathology and was assigned a Pathologic Alteration Score (PAS) of 1.2, or 3 in order of increasing severity. The PAS of the rectal specimens from the drug group was 1.6 +/- 0.7, and that of the controls 2.3 +/- 0.8. The PAS of the drug group was significantly lower than the control group (P = 0.008). The data suggest that misonidazole is a radioprotector for normal tissue.

Animals↗
PubMed1978

On the interaction of histone Hl and Hl peptides with DNA. Sedimentation, thermal denaturation and solubility studies.

The interactions in buffered 0.14 M NaCl (pH 7.0) of DNA, native or sonicated, with histone Hl and with its fragments N-Hl (residues 1-72) and C-Hl (residues 73-COOH), have been studied by using the techniques of sedimentation, thermal denaturation and solubility. Histone Hl shows a preferential affinity for high molecular weight DNA in comparison with sonicated DNA. The binding of histone Hl to sonicated DNA in 0.14 M NaCl is reversible and the reversibility decreases with time. These findings are consistent with the view that Hl is cooperatively distributed along DNA molecules and that this distribution is energetically more favoured for long DNA than for sonicated DNA. It has been found that under conditions of moderate salt concentration, the C-terminal region is the main one responsible for the interaction of Hl with DNA, and also for a cooperative distribution of the histone along the DNA molecules. Addition of urea to the solution produces a decrease of solubility of Hl-DNA complexes. This effect reflects an additional condensation of the complex, which is probably related to the unfolding of the globular part of the histone. It is suggested that this globular region does not play a substantial role in the condensation of Hl-DNA complexes. A model which takes into account the presence of free lysyl and phosphate groups within the complex is discussed.

Animals↗
PubMed1976

[The chromosome bands. Significance for clinical and cytogenetic research (author's transl)].

The methods of performing chromosomal investigations have been fundamentally changed in the last few years through the discovery of differential staining methods. While only a rough classification of the chromosomes into single groups could be carried out earlier, it is now possible to identify every individual pair of chromosomes on the basis of a typical pattern of bands. By means of these banding techniques smaller chromosomal variations can be recognized which were overlooked earlier and which have led to the delineation of new chromosomal malformation syndromes. In the present work, the modern methods of chromosome analysis are reviewed. Examples from clinical diagnosis show the necessity of using these techniques.

Abnormalities, Multiple↗
PubMed1976

Genetic counselling in cases of anal and rectal atresia.

The familial occurrence of anal and rectal atresia is investigated in literature including a material of 169 patients of children's hospitals in Munich. Positive family history was found for only one of 169 patients. The mode of inheritance in those families with more than one affected member is generally considered to be autosomal recessive, although several families with X-chromosomal recessive inheritance have been described. In approximately 50% of the cases, anal atresia is associated with other malformations. Twin studies indicate that genetic factors play only a minor role in the etiology. The genetic risk in cases of isolated anorectal atresia is estimated to be well below 1%.

Anal Canal↗
PubMed1975

The magnitude of electrostatic interactions in inhibitor binding and during catalysis by ribonuclease A.

It is demonstrated that a model of nucleotide binding to ribonuclease A similar to that proposed by Hammes and coworkers (G. G. Hammes (1968), Adv. Protein Chem. 23, 1) is at least, approximately applicable for both cyclic nucleotide substrates and mononucleotide inhibitors at pH values less than or equal to 6.5 and as a function of ionic strength. Calorimetric data on various inhibitors show that the binding reaction can be thermodynamically dissected into a contribution arising from van der Waal's interaction of the nucleoside moiety, characterized by a large negative enthalpy change, and a contribution arising from electrostatic interactions between the negatively charged phosphate group of the inhibitor and the positively charged protein fabric, characterized by a large positive unitary entropy change. Assuming a catalytic mechanism involving the formation of a dianionic pentacoordinated phosphate transition state intermediate, the magnitude of the effect of electrostatic interactions on the overall rate enhancement by the enzyme is estimated to be 2 times 10(2) to 10(6). It is suggested that this effect, along with substrate approximation effects, is sufficient to "explain" the catalytic behavior of the enzyme.

Binding Sites↗
PubMed1975

Physicochemical studies on tryptic digestion of bovine fibrinogen.

The high molecular weight fragments observed during tryptic digestion of bovine fibrinogen and the variation of their relative proportion with time has been studied. Separation of the different molecular species was carried out by gel filtration and the molecular weights of the isolated fragments were determined by sedimentation equilibrium and from their electrophoretic mobilities in sodium dodecylsulfate-polyacrylamide gels. The fibrinogen is degraded by trypsin into distinct fragments, with molecular weights of 270 000, 170 000, 90 000 and 50 000 accompanied by a series of smaller fragments whose properties were not investigated. The relative proportion of the components was estimated from area measurements on scans of the stained gels obtained after electrophoresis in the presence of sodium dodecylsulfate. The relative concentration and the molecular weight of each component established its molar concentration in each of the digestion mixtures obtained after varying incubation times (1-60 min). These data were used for a kinetic analysis of the process. The kinetic model derived on the basis of the trinodular model of fibrinogen (see Appendix) gave a very good representation of all the experimental results.

Animals↗
PubMed1975

[Prenatal diagnosis of Sandhoff's disease (GM2-gangliosidosis, type 2)].

The diagnosis of GM2-gangliosidosis type 2 (Sandhoff's disease) was made prenatally (23rd week of pregnancy) by amniocentsis. A sibling with "Tay-Sachs disease" had died shortly before. Severe deficiency of total beta-hexosaminidase was found in amniotic fluid and amnion-cell culture. After interruption of the pregnancy the enzyme defect was also found in the fetal brain tissue and the concentration of ganglioside GM2 was three times normal, confirming the diagnosis.

Amniocentesis↗