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Biomedical subjects

R Haas

Publications and source records attributed to R Haas.

At least 19 recordsLinked to original sources

A novel SH-type carboxypeptidase in the inner membrane of rat-liver mitochondria.

A carboxypeptidase from rat liver mitochondria was partially purified by discontinuous sucrose gradient centrifugation, washes with NaCl/KBr/Tris buffer, and solubilization with 2 M NaCl in the presence of soybean trypsin inhibitor bound to CM-cellulose. By means of dodecylsulfate/polyacrylamide gel electrophoresis a molecular weight of 34,500 was determined; a value of 38,000 was estimated by Sephadex G-100 gel filtration. The carboxypeptidase was completely inhibited by 3 mM Hg2+. In the presence of 3 mM Cu2+ 50% of the catalytic activity was inhibited. Among several peptides tested Cbz-Ala-Phe, Cbz-Leu-Phe, Cbz-Phe-Leu, and Cbz-Phe-Phe, were good substrates. The enzyme activity exhibited a pH optimum of around 9 with Cbz-Ala-Phe as a substrate. After submitochondrial fractionation it was found that the carboxypeptidase is located in the inner mitochondrial membrane.

Animals

The localization of an intracellular membrane-bound proteinase from rat liver.

To localize the membrane-bound, histone-degrading proteinase, which was previously isolated from the mitochondrial fraction, nuclei, mitochondria, lysosomes, peroxisomes, smooth and rough endoplasmic reticulum, ribosomes and plasma membranes were prepared from a rat liver homogenate according to established methods and characterized by marker enzyme activities. The isolated subcellular fractions were treated with digitonin, and subjected to a discontinuous sucrose gradient centrifugation. The material, which sedimented through 1.74 M surcrose was analyzed in respect to the various marker enzymes and for proteolytic activity. Proteinase activity was found in the material obtained after digitonin treatment and step gradient centrifugation of mitochondria. This finding shows the occurrence of a proteinase in mitochondria; After fractionation of mitochondria into outer and inner membrane, intermembrane fraction and matrix, the proteinase could be localized exclusively in the inner mitochondrial membrane. A possible physiological function of the enzyme during the biosynthesis of inner membrane constituents is discussed.

Animals

[Familial peroxidase-deficiency and acute myeloic leukemia (author's transl)].

A complete lack of myeloperoxidase (MPO) was demonstrated in a boy suffering from acute myeloic leukemia during the acute phase of the disease and after a remission was achieved. A partial defect of MPO was demonstrated in the patient's father, no further abnormalities were seen in other members of the family. The fine structure of the patient's neutrophils and monocytes appeared normal, no activity of MPO was demonstrated on the fine structural level. In the father's neutrophils transitional forms between cells exhibiting a normal MPO activity and those without activity were demonstrated. The neutrophil bactericidal activity was strongly inhibited in the patient and decreased in his father. Normal values were found in: NBT test, chemotaxis, serum-dependent phagocytosis, number of B and T lymphocytes, serum immunoglobulins, and complement. A possible connection between MPO deficiency and leukemia is discussed.

Adolescent

[Tourism and travel].

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Communicable Disease Control

[Tourism and travel].

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Communicable Disease Control

[Rubella immunization--immunity after 4 years (author's transl)].

The rubella antibody titres were evaluated in 158 girls who had been seronegative prior to immunization and had been immunised 4 years previously (1971) with the rubella vaccine HPV77DE5. In 138 girls (87%) the 1975 titres were unchanged in comparison with 1971. Only in 5 girls (3.2%) the titres had decreased by up to 2 log2 steps. In two patients the titre reached the critical value of 1:8 which must be considered negative due to the high sensitivity of the haemagglutination inhibition test. A titre increase by two or more steps was observed in 15 girls (9.5%). A third of the titre increases might be due to reinfection with rubella wild virus which would correspond to a reinfection rate of less than 1% per year. Present knowledge indicates that reinfection during pregnancy does not endanger the unborn child.

Adolescent

[Vaccination complications after oral poliomyelitis vaccination (author's transl)].

A vaccination complication is only to be recognized if, taking into consideration the incubation time, the clinical picture coincides with that of spontaneous poliomyelitis. Apart from exceptional cases, virological studies are only of importance for the assessment if they are carried out in the acute or subacute stages. Only six out of more than 150 cases could be accepted as vaccination complications.

Adolescent

[Inoculation for tourism (author's transl)].

The inoculations prescribed or recommended by the authorities responsible on the basis of the International Health Regulations for international tourism are first discussed and the contraindications gone into. Then some inoculations or measures for specific prophylaxis are presented for which there are no international regulations, but which have a particular significance from the point of view of tourism. These are inoculations against poliomyelitis, tetanus, typhoid fever and prophylaxis of hepatitis A with conventional gamma globulin.

Antigens