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Biomedical subjects

H Frank

Publications and source records attributed to H Frank.

At least 19 recordsLinked to original sources
PubMed1978

Enantiomer labelling, a method for the quantitative analysis of amino acids.

Enantiomer labelling a method for the quntitative analysis of optically active natural compounds by gas chromatography, involves the use of the unnatural enantiomer as an internal standard. With Chirasil-Val, a chiral stationary phase that is thermally stable up to up to 240 degrees, the enantiomers of amino acids and a variety of other compounds can be separated and quantitated. Incomplete recovery from the sample, incomplete derivatization, hydrolysis and thermal decomposition of the derivative and shifting response factors can be compensated for by adding the unnatural enantiomer. The accuracy of amino acid analysis by enantiomer labelling is equal or superior to that of hitherto known methods. The procedure affords a complete analysis of peptides with respect to both amino acid composition and the optical purity of each amino acid.

Amino Acids↗
PubMed1978

Application of a solid-phase radioimmunoassay and immune electron microscopy for hepatitis A in diagnosis and research.

With crude virus suspensions from stool and antibodies from hepatitis-A patients, a solid-phase radioimmunoassay (RIA) for detection of hepatitis virus A (HVA) had antibodies against hepatitis virus A (anti-HVA) has been developed. Examples for the application of this test are demonstrated. Virus particles from the stools of the two patients were further characterized. Serologically, they were identical or very similar to the MS-1 strain. Isopycnic CsCl-gradient centrifugation of both strains revealed two peaks, but the particles of different densities did not differ in size or serologically. A modification of the RIA was also useful for determination of IgM antibodies in patients' sera fractionated by sucrose-density centrifugation. The application of the RIA method for serologic epidemiology is demonstrated by a comparison of anti-HVA prevalence in German and non-German women residing in Germany.

Adolescent↗
PubMed1978

Gas chromatographic--mass spectrometric analysis of optically active metabolites and drugs on a novel chiral stationary phase.

Chirasil-Val, a novel chiral polysiloxane-type stationary phase is capable of separating the enantiomers of optically active drugs and metabolites of several compound classes; alpha-amino acides, alpha-amino alcohols, glycols, aromatic and aliphatic alpha-hydroxy carboxylic acids and amines. Due to their high thermal stability, columns coated with Chirasil-Val may be coupled to a mass spectrometer. Potential applications of the new stationary phase include analysis of the optical purity of enantiomeric drugs, determination of the configuration of metabolites, and quantitation of optically active drugs and metabolites using the unnatural enantiometer as internal standard. Direct separation of enantimoers on Chirasil-Val is especially useful if only minute amounts of the optically active compounds are availalbe for analysis.

Chromatography, Gas↗
PubMed1978

Assembly of type C oncornaviruses: a model.

The salient features of this model for oncornavirus assembly are that uncleaved precursor molecules to the internal virus polypeptides possess specific recognition sites both for viral envelope constituents already inserted in the cell membrane and for the viral RNA. After orderly alignment of these components at the budding site, virus maturation proceeds through specific proteolytic cleavage of the precursor components and association of the resultant molecules into the characteristic type C virion substructures revealed by electron microscopy.

Cell Membrane↗
PubMed1977

[New sulfonamide-trimethoprim combination, Supristol. Results of a joint therapeutic trial (author's transl)].

The efficacy of a new low dosage trimethoprim-sulfamoxole combination (Supristol) was tested in a joint therapeutic study in 6 medical clinics or departments and in a general practice. A good therapeutic result (healing) was achieved in about 80% of the 143 patients included in the trial. The preparation was well tolerated. Symptoms of intolerance appeared in only 2% of the cases. It is assumed that the low dosage of the preparation influences the tolerance favorably without affecting the efficacy.

Acute Disease↗
PubMed1977

Hepatitis A-virus particles in stools of patients from a natural hepatitis outbreak in Germany.

During a hepatitis outbreak in Southern Germany 27 nm particles were visualized by immune electron microscopy in stools of two patients. These particles were sereologically identical or similar to hepatitis A-virus particles identified in the USA. The buoyant density of these particles was 1.34 g/cm3 as shown by cesium chloride density centrifugation. The particles were first observed in small numbers in a stool obtained 11 days, and in large numbers in stools obtained 6 and 7 days before the onset of jaundice. Few particles were seen on the day of the onset of jaundice and none thereafter. In both patients a sereoconversion to hepatitis A-virus as judged by immune electron microscopy could be demonstrated.

Disease Outbreaks↗
PubMed1977

Rapid gas chromatographic separation of amino acid enantiomers with a novel chiral stationary phase.

The use of novel polysiloxanes as stationary phase carrying chiral groups enables the separation of most amino acid enantiomers in a much shorter time than ever reported previously. Phases of this type exhibit very low volatility and high thermal stability and may be used in routine analysis with open tubular columns ant temperatures of at least 175 degrees C. Most protein amino acids are separated in a temperature program between 90 and 175 degrees C, thus obviating the need for multiple injections. Resolution factors are somewhat lower than those of other diamide phases containing the L-valine t-butyl-amide group, but are sufficient for resolution of almost all protein amino acid enantiomers.

Amino Acids↗
PubMed1977

Mn2+-sensitive, soluble adenylate cyclase in rat testis. Differentiation from other testicular nucleotide cyclases.

In subcellular fractions prepared from homogenate of adult rat testis adenylate cyclase (ATP pyrophosphate-lyase (cyclizing), EC 4.6.1.1) activity was found in the particulate, primarily 600 X g for 10 min, fractions, as well as in the cytosol. The properties of the adenylate cyclase in the cytosol differs substantially from the adenylate cyclase system associated with the 600 X g for 10 min particulate fraction. The cytosol enzyme, in contrast to the particulate adenylate cyclase, was found to be fluoride- and gonadotropin hormone-insensitive. The cytosol adenylate cyclase appears to be located in the germ cell while the particulate enzyme system in the non-germ cell component of the seminiferous tubules, The cytosol adenylate cyclase was found to be distinct also from the guanylate cyclase present in the rat testis cytosol. The adenylate cyclase appears to be located in the germ cell component while the guanylate cyclase, in the non-germ cell tubular component. Furthermore, it was found that the cytosol guanylate cyclase develops at an earlier stage of spermatogenesis, and precedes the development of the cytosol adenylate cyclase.

Adenylyl Cyclases↗
PubMed1976

On the induction of the hepatic tyrosine aminotransferase by quinolinic acid.

The induction of tyrosine aminotransferase by quinolinic acid is inhibited completely by cycloheximide and by alpha-amanitin, but only partially during the first 3 hours by 5-azacytidine and 8-azaguanine; longer treatment with 8-azaguanine, however, also prevents the major increase in enzyme activity. The hepatic concentration of cyclic AMP does not change after administration of quinolinic acid. Insulin, like hydrocortisone, acts additively to qlinolinic acid. The isoenzyme pattern of tyrosine aminotransferase is not changed cosniderably during induction of quinolinic acid. Most likely, quinolinic acid acts through its own mechanism of induction.

Amanitins↗
PubMed1975

Morphological, chemical, and antigenic organization of mammalian C-type viruses.

New features in the architecture of mammalian type C viruses, in particular knoblike surface projections and hexagonally arranged subunits on the core shell could be demonstrated by electron microscopy, taking advantage of newly developed preparation techniques. As examples, murine leukemia viruses (MuLVs) and newly isolated porcine and bovine C viruses are presented. The major proteins of a MuLV were isolated and partially characterized in chemical terms and with respect to their serological and other biological activities, such as interfering and hemagglutinating (HA) capacity. Most of the characterized proteins could be localized in particular substructures of the virion either by selective removal or isolation of electron microscopically identifiable constituents. The information obtained allowed the design of a more detailed model of mammalian C viruses. Special attention was devoted to the further characterization of interspecies antigens of mammalian C viruses. Different antigenic determinants were revealed. Their distribution allows further subgrouping of mammalian C viruses.

AKR murine leukemia virus↗