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Biomedical subjects

J Kraus

Publications and source records attributed to J Kraus.

At least 127 records · Page 7Linked to original sources
PubMed1990

Pyridoxine-unresponsive homocystinuria with an unusual clinical course.

Progressive premature atherosclerosis and associated thromboembolic complications are the main causes of morbidity and mortality in patients with homocystinuria. However, thrombosis is rarely the predominant or presenting manifestation leading to the diagnosis of homocystinuria. We report on an otherwise asymptomatic teenage boy of normal intelligence who had a superior sagittal sinus thrombosis documented by CT and MRI scans. He presented with pneumothoraces, papilledema, and transient right hemiparesis. He subsequently developed empyema and necrotizing pneumonia as well as deep venous thromboses. The diagnosis of pyridoxine-unresponsive homocystinuria was made on the basis of clinical chemistry analyses, enzyme assay, and clinical trial. He has remained symptom-free under treatment with betaine and methionine restriction. We suggest that there exists a subset of patients with pyridoxine-unresponsive homocystinuria who are at risk for thromboembolism, but who may remain undiagnosed because of an otherwise mild clinical course.

Adolescent↗
PubMed1990

Analysis of human chromosome 21: correlation of physical and cytogenetic maps; gene and CpG island distributions.

Human chromosome 21 has been analyzed by pulsed-field gel electrophoresis using somatic cell hybrids containing limited regions of the chromosome and greater than 60 unique sequence probes. Thirty-three independent NotI fragments have been identified, totalling 43 million bp. This must account for essentially the entire long arm, and therefore gaps remaining in the map must be small. The extent of the pulsed-field map has allowed the direct correlation of the physical map with the cytogenetic map: translocation breakpoints can be unambiguously positioned along the long arm and the distances between them measured in base pairs. Three breakpoints have been identified, providing physical confirmation of cytogenetic landmarks. Information on sequence organization has been obtained: (i) 60% of the unique sequence probes are located within 11 physical linkage groups which can be contained in only 20% of the long arm; (ii) 9/21 genes are clustered within 4%; (iii) translocation breakpoints appear to occur within CpG island regions, making their identification difficult by pulsed-field techniques. This analysis contributes to the human genome mapping effort, and provides information to guide the rapid investigation of the biology of chromosome 21.

Base Composition↗
PubMed1990

Prenatal ultrasound diagnosis of multiple cardiac rhabdomyomas.

We report on a neonate with multiple cardiac rhabdomyomas, including a huge rhabdomyoma of the left ventricular posterior wall. Prenatal ultrasonography performed because of supraventricular tachycardia led to the diagnosis in the 28th week of gestation. Postnatal echocardiography confirmed the prenatal diagnosis. The tumor could not be removed surgically and the child died as a result of intractable arrhythmia at the age of 5 days. The diagnosis of multiple cardiac rhabdomyomas was confirmed by autopsy.

Female↗
PubMed1990

The alpha-A-crystallin and cystathionine beta-synthase genes are physically very closely linked in proximal mouse chromosome 17.

Murine genes homologous to those contributing to the Down syndrome (DS) phenotype in man are currently of interest because of their potential for providing animal models for the study of specific DS symptoms. Most of the genes mapping to human chromosome 21q22, where the DS genes are concentrated, are related to sequences located on mouse chromosome 16. Others, however, are known to map to mouse chromosome 10, and two genes, cystathionine beta-synthase (Cbs) and alpha-A-crystallin (Crya-1), have been localized to the proximal portion of mouse chromosome 17. In this paper, we show that the two genes mapping to human chromosome 21q22 and mouse chromosome 17 are very tightly linked in mouse, being separated by at least 70 kb, but not more than 130 kb. The very close physical linkage of mouse Cbs and Crya-1, combined with data that localize homologs of the closely flanking markers H2k and Pim-1 to human chromosome 6, suggests that the human 21q22/mouse chromosome 17 conserved segment is of a very limited total physical size and is likely to contain a relatively small number of genes.

Animals↗
PubMed1990

[Pathologic findings in auditory brain stem evoked potentials in 10 children with brain stem tumors].

The authors examined brain stem acoustic evoked potentials (BAEP) in 10 children aged 2-14 years with tumours in the posterior cranial fossa infiltrating the cerebellum and brain stem. The tumours were diagnosed by computed tomography and in eight patients confirmed on operation. For stimulation a monaural click was used. The authors assessed the latency of waves, intervals between and investigated the presence of waves and evaluated their amplitudes. They compared the results with normal values. In abnormal findings the latency of components was delayed, the components were generated in a rostral manner from the site of the lesion in all children. In four patients with severe affections of the brain stem the investigated components were lacking. In nine patients the BAEP evoked by monaural stimulation helped to asses the lateralization of the lesion. In eight patients a bilateral abnormality of the V wave was recorded. The most sensitive indicator for assessment of the site of the lesion was assessment of the interval between two consecutive waves.

Adolescent↗
PubMed1990

Molecular biology of atherothrombotic brain infarction.

Because reduced high density lipoproteins may contribute to atherothrombotic brain infarction, we performed molecular biologic and metabolic studies to characterize high density lipoprotein metabolism with respect to its role in reverse cholesterol transport, to clone the high density lipoprotein receptor, and to determine gene polymorphism for apolipoprotein A-I, the major protein of high density lipoprotein, because altered structure may impair reverse cholesterol transport. For high density lipoprotein metabolism measurements, high density lipoprotein 3 was isolated, purified, and labeled with iodine-125. The radiolabeled high density lipoprotein 3 was reinjected, and daily blood samples were taken for 10 days. Synthesis rates and fractional catabolic rates were determined from the specific activities and daily decrements. Preliminary data indicate that stroke-prone individuals' fractional catabolic rates for high density lipoprotein 3 are twice those of normal individuals. Also, the conversion of high density lipoprotein 3 to high density lipoprotein 2 is reduced in these individuals, suggesting that high density lipoprotein may be abnormally processed in individuals prone to atherothrombic brain infarctions. We surveyed more than 100 patients with carotid stenosis using a 2.2-kb probe for the apolipoprotein A-I gene. A subset of these patients displays polymorphism with restriction enzymes SacI or PstI. These preliminary findings suggest that gene polymorphism for apolipoprotein A-I may provide a molecular clue of atherothrombic brain infarction.

Arteriosclerosis↗
PubMed1990

[Developmental study of somatosensory evoked potentials in the median nerve in children].

By evaluation of the findings in 134 healthy children aged one month to 14 years the authors obtained normal values of SEP of the median nerve and investigated developmental changes which involved among others an increased rate of conduction along the fibres of the peripheral neuron and changes of the distance between electrodes. From the findings ensued that the conduction velocity in mixed fibres of the median nerve in the portion wrist- Erb's point increased most in children aged 2-4 years where it increased to as much as 10 ms-1, while at the age of 1 month to 2 years the increase was 6 ms-1. This difference can be explained by a different maturity of fibres transmitting the impulses. The great scatter in the youngest children confirmed this view. The latency of the cortical response (N 18) in the youngest children was longest and declined gradually. At the age of 2-4 years it was even lower than in older children which may be explained by a more rapid transmission of the impulse in this age group than was the increment of distances between electrodes. Later, on the other hand, the growth of the extremities was more manifested. The above changes were less apparent in latencies of the spinal wave (N 13) and in values of the central conduction time where some part may have been played also by the relative maturity of structures of the brain stem.

Adolescent↗
PubMed1989

Molecular cloning and nucleotide sequence of cDNAs encoding the precursors of rat long chain acyl-coenzyme A, short chain acyl-coenzyme A, and isovaleryl-coenzyme A dehydrogenases. Sequence homology of four enzymes of the acyl-CoA dehydrogenase family.

cDNAs encoding the entire coding regions of the precursors (p) of rat long chain acyl-CoA (LCAD), short chain acyl-CoA (SCAD) and isovaleryl-CoA dehydrogenase (IVD) have been cloned and sequenced. Three cDNAs for rat liver LCAD together cover a 1440-base pair region. These cDNAs encode the entire 430-amino acid sequence of pLCAD, including the 30-amino acid leader peptide and the 400-amino acid mature LCAD. A single 1773 base pair cDNA for rat SCAD covers the entire coding region (414 amino acids), including the 26-amino acid leader peptide and the 388-amino acid mature peptide. Four identified IVD cDNAs, when combined, encompass a 2104 base region, and encode 424 amino acids including a 30-amino acid leader peptide and the 394-amino acid mature peptide. The identities of all cDNA clones have been confirmed by matching the amino acid sequences predicted from the respective cDNAs to the amino-terminal and tryptic peptide sequences derived from the corresponding purified rat enzyme. Comparison of the sequences of four rat acyl-CoA dehydrogenases, including LCAD, MCAD, SCAD, and IVD, and two of their human counterparts (MCAD and SCAD) reveals a high degree of homology (57 invariant and 92 near invariant residues: 30.6-35.4% of identical residues in pairwise comparisons), suggesting that these enzymes belong to a gene family and have evolved from a common ancestral gene.

Acyl-CoA Dehydrogenase↗
PubMed1989

[Ileus symptoms due to 3 distinctively differentiated small intestine carcinomas in nontropical sprue].

Recently recurring abdominal pain, bouts of diarrhoea and weight-loss of 15 kg developed in a 50-year-old woman who had for 18 years been treated by diet for nontropical sprue. She was hospitalized for signs of mechanical ileus. Radiological examination revealed three stenosing small intestine tumours, one of them obstructing the lumen. After resection of the affected segments, with end-to-end anastomosis, histological, histological examination of the surgical specimens demonstrated three small intestine carcinomas of different grades of differentiation. The largest tumour had already metastasized to four regional lymph nodes. This case illustrates the potentially precancerous nature of nontropical sprue which has been present for many years and thus requires careful follow-up.

Adenocarcinoma↗
PubMed1989

Chemical structure and biological activity of water-soluble polysaccharides from Cassia angustifolia leaves.

The water-soluble polysaccharides from Cassia angustifolia L. leaves were isolated and fractionated. The acidic polysaccharide fraction was separated into two subfractions S1 and S2 consisting of L-rhamnose, L-arabinose, D-galactose, and D-galacturonic acid. Further fractionation of the predominant S1 by GPC gave two fractions S1A and S1B with an average molecular weight of 2 x 10(6) and 1.5 x 10(5) d, respectively. Methylation analysis of S1A showed the presence of 1,4-linked galacturonic acid (31.0%), 1,2-linked rhamnose (14.5%), 1,2,4-linked rhamnose (15.8%), 1,3,6-linked galactose (15.3%), smaller amounts of 1,3-linked arabinose, 1.5-linked arabinose, and terminal galactose and arabinose residues. Mild acid hydrolysis of S1A indicated that the backbone consists of 1,4-linked galacturonic acid and 1,2-linked rhamnose residues in the ratio of 1:1. Every second rhamnose is connected via C-4 to arabinogalactan sidechains. The antitumor activity of the polysaccharide fractions was tested against the solid Sarcoma-180 in CD1 mice. Only S1A exhibited a significant antitumor activity with an inhibition rate of 51%.

Animals↗
PubMed1989

Molecular cloning of CD1a (T6), a human epidermal dendritic cell marker related to class I MHC molecules.

To investigate the structure, function, and control of CD1a, we have cloned a 1.6-kbp cDNA which encodes the expressed CD1a protein and includes untranslated 5' and 3' sequences and the poly-A tail. As the protein recognized by the monoclonal antibody OKT6, CD1a is a useful marker for Langerhans cells (LC). CD1a is found on these cells and on thymocytes, suggesting an important immunologic role for this molecule. We constructed a cDNA library in lambda gt10 using mRNA from MOLT-4, a cell line that expresses the CD1a surface antigen. We then screened the library with an oligonucleotide synthesized according to a known partial sequence for CD1a, and subcloned the cDNA and its restriction fragments into pGEM for sequencing and probe production. Based on this sequence the CD1a protein is predicted to consist of three extracellular domains (alpha 1-3), a hydrophobic transmembrane region, and a cytoplasmic tail. DNA 5' to the alpha 1 region may undergo alternative exon splicing. There is high sequence identity between the beta-2 microglobulin binding region of MHC I molecules and CD1a. The secondary structure predicted for CD1a is very similar to the actual structure of HLA-A2, a classical MHC I molecule. The similarity includes the beta pleated sheets and alpha helices which form the antigen binding groove of the alpha-1 and alpha-2 domains. The homology predicted between CD1a and HLA-A2 in these regions appears to exist on the level of secondary structure despite low primary nucleotide and amino acid sequence identity. The structural data and probes we have developed should facilitate studies of the function of CD1a as well as novel investigations of LC.

Amino Acid Sequence↗