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Biomedical subjects

R Haas

Publications and source records attributed to R Haas.

At least 325 records · Page 18Linked to original sources
PubMed1985

[Multiple sclerosis and the electroencephalogram (computer EEG studies)].

A computerized analysis of EEg-records from 96 multiple sclerosis (MS) patients yielded about twice as many abnormal results (79%) in comparison to the usual visual EEG-evaluation (39%). The statistically significant (p less than 0.05) increase in slow frequencies in addition to beta frequencies to the cost of alpha, but especially the reduction in total percentage of alpha contribution to overall EEG-power discriminated most efficiently between MS-patients and our normal population. Thus, alpha index alone allowed for 87% correct classification of the normal population, and 73% of patients with normal visual EEG-records were correctly classified as belonging to the MS-population. Extending the patient group to include pathological visual EEG-records as well, the corresponding figures were 95% and 89%, respectively. The computerized EEG-analysis was thus clearly superior to the usual visual inspection.

Adult↗
PubMed1985

Selective hemisplenectomy for Hodgkin's disease.

Schellong's recommendation to do a selective splenectomy in Hodgkin's disease supported by our retrospective histological findings in biopsies of lymph nodes and spleens of 25 patients. In addition, we recommend a hemisplenectomy instead of a splenectomy in cases of involvement of the lymph nodes at the pancreatic tail and at the hilus of the spleen. Hemisplenectomy, which is not a more difficult or more time-consuming operation, provides more security in judging an invasion of the spleen.

Biopsy↗
PubMed1985

Coincidence of infectious osteomyelitis and disseminated neuroblastoma: a diagnostic dilemma solved by scintigraphic imaging.

The case of a 41/2-year-old girl with disseminated neuroblastoma and concomitant osteomyelitis is reported. Neuroblastoma was detected in the vertebral column, the right suprarenal fossa, the left side of cranium and in bone marrow aspirates. Osteomyelitis was present in the left femur and was due to Salmonella tennessee. For the first time in the literature the two lesions were demonstrated by means of simultaneous 131I-MIBG and 99mTc-DPD scintigraphy. The diagnoses were proved by direct histological and microbiological studies.

3-Iodobenzylguanidine↗
PubMed1985

Quantitative identification of N-terminal amino acids in proteins by radiolabeled reductive methylation and amino acid analysis: application to human erythrocyte acetylcholinesterase.

A novel method of determining N-terminal amino acids in proteins is introduced. Reductive methylation of a protein with radiolabeled formaldehyde methylates both the alpha-amino group of the N-terminal amino acid and the epsilon-amino groups of Lys residues. The radiomethylated amino acids are stable to acid hydrolysis, and each of 16 possible hydrolysis-stable N-terminal amino acids can be identified by the unique elution positions of its N alpha-methyl and N alpha,N alpha-dimethyl derivatives with an appropriate amino acid analyzer elution schedule. The technique is at least as sensitive as other N-terminal amino acid determinations and, in addition, permits a quantitative evaluation of the number of N-terminal groups in a sample. Reductive methylation of bovine serum albumin revealed N-terminal Asp at a stoichiometry of 0.97 amino acid residue per polypeptide, while methylation of prolactin resulted in 0.86 residue of N-terminal Thr per polypeptide. Human erythrocyte acetylcholinesterase contained two N-terminal amino acids with stoichiometries of 0.66 Glu and 0.34 Arg per 70-kDa subunit. Identification of Glu as the principal N-terminus of acetylcholinesterase was confirmed by Edman sequencing.

Acetylcholinesterase↗
PubMed1985

A plasmid cloning system utilizing replication and packaging functions of the filamentous bacteriophage fd.

DNA cloning vectors were developed which utilize the replication origin (ori) of bacteriophage fd for their propagation. These vectors depend on the expression of viral gene 2 that was inserted into phage lambda, which in turn was integrated into the host genome. The constitutive expression of gene 2 in the host cells is sufficient for the propagation of at least 100 pfd plasmids per cell. In addition to the fd ori, the pfd vectors carry various antibiotic-resistance genes and unique restriction sites. Some of these vectors have no homologies to commonly used pBR plasmids or to lambda DNA. The nucleotide sequence of the vectors can be deduced from published sequences. Large DNA inserts can be stably propagated in pfd vectors; these are more stable than similar DNA fragments cloned in intact genomes of filamentous bacteriophage. Inclusion of phage sequences required for efficient phage packaging and infection with a helper phage resulted in formation of phage particles containing single-stranded plasmid genomes. Growth at 42 degrees C without selective pressure results in loss of pfd plasmids.

Bacteriophage lambda↗
PubMed1985

What is the actual incidence of peritonitis in maintenance peritoneal dialysis? A prospective study.

Generally, the incidence of peritonitis in maintenance peritoneal dialysis programs is calculated as a percentage of the total number of treatments or as the number of episodes per patient-months. Both statistical methods give the wrong impression that peritonitis is seldom observed. However, peritonitis is still the major and unsolved challenge to successful long-term peritoneal dialysis. The lack of a standard and homogeneous definition of peritonitis is another critical point that prevents a rational interpretation of the published experiences. In the present study, dialysate cell counts of greater than 1,100 cells/mm3 were assumed to be the first sign of peritoneal infection. As long as more signs and symptoms are required for recognizing peritonitis (fever, abdominal pains, positive cultures), the statistical probability of making such a diagnosis shows the characteristics of a Poisson distribution. It is concluded that in long-term peritoneal dialysis, the currently used statistical methodology for evaluation of the incidence of peritonitis, including the clinical definition of this complication, is misleading. Dialysate cell counts appear to be the more sensitive sign for early diagnosis of peritonitis.

Adult↗
PubMed1985

[Radioimmunological determination of neopterin in blood donors].

In 518 sera from blood donors below 30 years of age Neopterin was determined by radioimmunoassay. 21 of these patients (= 4.05%) showed elevated serum levels for Neopterin. By clinical investigation of these cases viral infections of the upper airways were found. Furthermore after elimination of elevated values significant differences in normal Neopterin serum levels could be demonstrated for female and male blood donors (p less than 0.01). Because elevated Neopterin serum levels indicate immune responses to several antigens, determination of Neopterin from serum may be useful for detection of infectious blood samples.

Adolescent↗
PubMed1984

Binding of fibronectin to gelatin and heparin: effect of surface denaturation and detergents.

The specific binding of fibronectin to collagen and heparan sulfate is important in cell adhesion and formation of connective tissue. We have used miniaturized affinity chromatography of 125I-labeled fibronectin on gelatin- or heparin-conjugated Sepharose as a model system to further study features of these interactions after a variety of treatments of the fibronectin. We find that fibronectin's affinity is abolished following adsorption and desorption from tissue culture plastic, diminished by the strong ionic detergent sodium dodecyl sulfate (SDS), and unaffected by nonionic detergents or the zwitterionic detergent Zwittergent 3-12. This identifies the latter as a gentle extractant suitable for a variety of uses in studying cell-substratum adhesion.

Adsorption↗
PubMed1984

[Nocturnal levels of serum aminoacids and growth hormone].

During the night, mostly between 2 and 4 a.m., a peak of the concentrations of amino acids in human blood serum can be seen. The paper shows, that this phenomenon may be caused by the different secretion of the growth hormone depending on sleep or wakefulness of the person tested.

Amino Acids↗
PubMed1984

The role of lipoteichoic acid biosynthesis in membrane lipid metabolism of growing Staphylococcus aureus.

Pulse-chase experiments with [2-3H]glycerol and [14C]acetate revealed that in Staphylococcus aureus lipoteichoic acid biosynthesis plays a dominant role in membrane lipid metabolism. In the chase, 90% of the glycerophosphate moiety of phosphatidylglycerol was incorporated into the polymer: 25 phosphatidylglycerol + diglucosyldiacylglycerol leads to (glycerophospho)25-diglucosyldiacylglycerol + 25 diacylglycerol. Glycerophosphodiglucosyldiacylglycerol was shown to be an intermediate, confirming that the hydrophilic chain is polymerized on the final lipid anchor. Total phosphatidylglycerol served as the precursor pool and was estimated to turn over more than twice for lipoteichoic acid synthesis in one bacterial doubling. Of the resulting diacylglycerol approximately 10% was used for the synthesis of glycolipids and the lipid anchor of lipoteichoic acid. The majority of diacylglycerol recycled via phosphatidic acid to phosphatidylglycerol. Synthesis of bisphosphatidylglycerol was negligible and only a minor fraction of phosphatidylglycerol passed through the metabolically labile lysyl derivative. In contrast to normal growth, energy deprivation caused an immediate switch-over from the synthesis of lipoteichoic acid to the synthesis of bisphosphatidylglycerol.

Diglycerides↗
PubMed1984

Adhesion site composition of murine fibroblasts cultured on gelatin-coated substrata.

Fibroblasts in vivo adhere to a collagenous extracellular matrix. We present here a combined morphological and biochemical analysis of the adhesion sites of fibroblast-like cells cultured in vitro on gelatin-coated plastic, for comparison with earlier model studies using serum (plasma-fibronectin [pFn])-coated plastic. Scanning electron microscopy shows that cell adhesion to the gelatin is quite similar to that on plastic, but with some morphological differences reminiscent of those caused by higher concentrations of fibronectin adsorbed to the substratum. Measurement using 125I-radiolabeled pFn shows the level of substratum-bound pFn adsorbed from serum in the growth medium is, however, comparable on gelatin or plastic; thus, differences due to pFn must be attributed to the quality of the adsorbed protein; not its absolute quantity. Gel electrophoretic analysis of cellular adhesion sites formed on the two substrata shows their compositions to be qualitatively similar, suggesting again that the same fundamental adhesion processes are involved. However, three protein bands do change; notably, cellular fibronectin is increased on gelatin. These three proteins are also the most resistant to saline extraction, suggesting their intrinsic importance in the adhesion sites. The nature of the growth substratum thus appears to modulate a fundamentally unvarying morphology and adhesion site composition of the cells that adhere to it.

Animals↗
PubMed1984

Pilus genes of Neisseria gonorrheae: chromosomal organization and DNA sequence.

We have mapped two regions of the Neisseria gonorrheae genome, pilE1 and pilE2, which are involved in pilus expression. When the cells are in the piliated P+ state, these two loci carry sequences necessary for pilin production. A silent locus, pilS1, also maps near pilE1 and pilE2. pilS1 contains structural gene information but lacks pilus promoter sequences. The pilus gene sequences in pilE1 and pilE2 are identical in strain MS11.

Amino Acid Sequence↗
PubMed1984

Brain mitochondrial metabolism in experimental thiamine deficiency.

Thiamine deficiency causes Wernicke's encephalopathy, although the precise mechanism is unknown. We used a low-thiamine diet in conjunction with a thiamine analog, pyrithiamine, as a model of severe thiamine deficiency in rats. We investigated the function of intact, coupled mitochondria isolated from both brain and liver. State 4 respiration did not change in the thiamine-deficient animals. Brain state 3 rates fell in thiamine-deficient animals when pyruvate/malate, alpha-ketoglutarate, or glutamate were used as substrate. Liver state 3 rates were depressed only when pyruvate/malate was substrate. Activities of brain and liver pyruvate dehydrogenase complex and alpha-ketoglutarate dehydrogenase complex were depressed in the thiamine-deficient group. We conclude that the mitochondrial abnormalities resulting from thiamine deficiency are secondary to depression of thiamine-mediated enzyme activity, rather than from a putative role of thiamine in chemiosmotic coupling, and that the resulting abnormalities in ATP synthesis and perhaps in glutamate catabolism result in the irreversible neurologic defect seen in this disease.

Animals↗
PubMed1984

Inhibitory effect of cloxacepride on compound 48/80-induced histamine and serotonin release from rat mast cells.

Cloxacepride, a potent inhibitor of passive cutaneous anaphylaxis (PCA) in the rat, was evaluated for in vitro inhibitory effect on 48/80-induced histamine and serotonin release from rat mesenterial mast cells. Significant inhibition and linearity of concentration and effect was found in the concentration range of 10 to 50 microM. The IC50 was determined to 21 microM (histamine) and 19 microM (serotonin). A simultaneous liberation of both mediators from mast cells is indicated from nearly identical IC50. LDH increase in the supernatant of the incubation mixture by cell damage resulted from higher concentrations of cloxacepride (greater than 50 microM). The high concentration of 10 micrograms/ml releaser 48/80 did not affect or diminish the effect of cloxacepride, while the reference compounds cromolyn sodium (DSCG) and theophylline were inactive under these conditions. The substantial inhibition of the PCA reaction and of the mediator release from mast cells provides cloxacepride a promising potential antiallergic drug.

Animals↗