Biomedical subjects

G Richter

Publications and source records attributed to G Richter.

At least 145 records · Page 8Linked to original sources

PubMed1992

Determinants of recall of parental rearing behavior. The influence of age or loss of parents by separation or death.

In a study of 562 psychiatric inpatients and 251 healthy controls, relationships between age of proband and related life events (divorce of parents, death of a parent) and the perceived parental rearing have been investigated. The inverse relationships obtained could be explained by the higher number of divorced parents among younger subjects with negatively experienced parental rearing practices on the one hand and an idealization of the parents who had died on the other hand. In psychiatric patients these relationships and differences were more pronounced pointing to the importance of parental rearing as a vulnerability factor for mental problems during adulthood. The necessity to control for age in studies of perceived parental rearing became obvious by the present results.

Adult↗

PubMed1992

Development of a new dynamic method for quantitative evaluation of in vitro hemocompatibility of biomedical materials.

In this study a new dynamic method is introduced allowing the estimation of blood cell adhesion on flat test surfaces by measuring the cell loss in the bulk phase of surface contacting test blood under defined rheological conditions. This was achieved by constructing a novel test chamber permitting the contact of small amounts of blood with a large geometrical test surface. The construction consists of a spiral-shaped flow channel of 0.3 cm width, 0.02 cm height and 78 cm length covered with the biomaterials to be tested from both sides. Laminarity of blood flow in the conduit was confirmed theoretically by the calculation of an equivalent to the Reynolds number for curved systems the so-called Dean number. Furthermore, flow laminarity was proved experimentally finding that the flow rate of blood with different hematocrit values was proportional to the hydrostatic pressure applied. The applicability of the novel 'spiral method' for the estimation of hemocompatibility was demonstrated by evaluation of platelet adhesion onto different polymers in comparison to siliconized and fibrinogen coated glass as reference surfaces. Additionally, it was possible under distinct conditions to determine the adhesion of leucocytes and the detachment of platelet aggregates. Therefore, it was concluded that the spiral method can be used for the assessment of the hemocompatibility of flat biomedical polymers. As main advantages of the new method can be considered the high time efficiency and accuracy without labelling or optical detection of adherent cells.

Acrylic Resins↗

PubMed1992

Abnormal TNF production in prediabetic BB rats is linked to defective CD45R expression.

The genetic basis and diabetes association of aberrant tumour necrosis factor-alpha (TNF-alpha) production by activated peritoneal macrophages in diabetes-prone (dp) biobreeding (BB) rats was analysed. Southern blot analysis could not detect a restriction fragment length polymorphism for the TNF gene distinguishing dp BB rats from Wistar (Wi) rats and diabetes resistant (dr) BB rats. The contiguous genetic arrangement of lymphotoxin (LT) and TNF genes described in mouse and man was also found in the rat by cloning a chromosomal region covering both genes. In search of a polymorphic marker we amplified a (CA)n:(GT)n microsatellite in the TNF promoter region by polymerase chain reaction (PCR). We detected two alleles, (CA)26 and (CA)33, but no correlation with diabetes risk was seen. Crosses between dp BB rats and Wi or Lewis. 1A (Lew. 1A) rats, respectively, indicated that aberrant TNF-alpha production of activated macrophages is inherited dominantly with only weak penetrance. Analysis of the F2 generation and backcrosses with the two parental strains showed that aberrant TNF production co-segregates with lymphopaenia and defective CD45R expression, markers known to reflect a diabetes predisposing gene(s) outside the RT1 complex. We conclude that a single linkage group is responsible for both aberrant TNF production and defective T-cell maturation in dp BB rats.

Animals↗

PubMed1992

[Apolipoprotein E mobility between plasma lipoproteins in intravenous administration of fat emulsions (MCT, LCT)].

Apolipoprotein (apo) E plays a key role in chylomicron metabolism as a ligand for their uptake via the apo B/E- and apo E receptor into the liver. Apo E is not primarily synthesized with chylomicrons but is postprandially transferred to chylomicrons during lipolysis in plasma from high density lipoproteins (HDL). As triglyceride-/phospholipid emulsions given intravenously acquire apolipoproteins in plasma, we set out to investigate a possible transfer of apo E to these artificial lipoproteins and its role during their further metabolism. To this end healthy normolipemic volunteers and carriers of the frequent apo E3/3 phenotype were infused lipid emulsions. The lipoprotein-distribution of apo E during MCT and LCT infusions was monitored over four hours. Infusion of MCT and LCT resulted in a substantial transfer of apo E from HDL to triglyceride rich lipoproteins. During MCT infusion the transfer of apo E seemed to occur more rapidly than during LCT infusion. This could be one of the reasons for the faster metabolism of MCT over LCT. Plasma levels of apo E also decreased significantly during infusion of triglyceride/phospholipid emulsions in accordance with the role of apo E as a ligand for the uptake of the artificial particles into the liver.

Apolipoproteins E↗

PubMed1991

Characterization of glucagon-like peptide-I(7-36)amide receptors of rat lung membranes by covalent cross-linking.

125I-labelled GLP-I(7-36)amide was cross-liked to a specific binding protein in rat lung membranes using disuccinimidyl suberate. A single radio-labelled band at Mr 66,000 was identified by SDS-PAGE after solubilization of the ligand-binding protein complex which is consistent with the presence of a single class of binding sites on rat lung membranes. The band was undetectable when 1 mumol/l GLP-I(7-36)amide was included in the binding assay. No change in the mobility of the band was observed under reducing conditions suggesting that the binding protein in the receptor is not part of a larger disulphide-linked protein. The intensity of the radiolabelled protein band was reduced when the incubation with 125I-labelled GLP-I(7-36)amide was carried out in the presence of guanine nucleotides suggesting that the GLP-I(7-36)amide receptor is coupled to the adenylate cyclase system.

Animals↗

PubMed1991

The interleukin-6 gene locus seems to be a preferred target site for retrotransposon integration.

Recently, we have observed the insertion of a retrotransposon into the interleukin-6 (Il-6) locus of a mouse somatic cell line. Here we report the characterization of Il-6 genomic regions from both mouse and rat. Restriction site analysis, DNA sequence analysis, and computer-assisted search revealed eight retrotransposon-like elements distributed over a 25 kilobase (kb) mouse Il-6 region. In the rat, five different retrotransposons have been identified within a 17 kb Il-6 region. The retrotransposons belong to the LINE-, Alu I or Alu II families, or to a rat specific class of retrotransposons. Some of the retrotransposons exhibit characteristic features such as target site duplication and a poly A-tract. Remarkably, several retrotransposons map to different chromosomal locations in the mouse and rat. A genealogical tree of mouse, rat, and human Il-6 loci demonstrates a series of retrotranspositions that recently occurred in evolution. These results suggest that the Il-6 locus serves as a preferred target site for retrotransposon integration during evolution.

Animals↗

PubMed1991

Perceived parental rearing, depression and coping behaviour. A pilot study in psychiatric patients.

Within the framework of Perris' vulnerability model of psychopathology the relationships between perceived parental rearing and coping behaviour in adulthood have been investigated. Rejecting and punitive rearing practices of both parents seem to contribute to the formation of intrapsychic, emotion-oriented coping strategies. The results indicate that childhood social experiences, in particular, parent-child relations, both directly affect vulnerability to psychopathological manifestations in later life and indirectly influence the conditions through the aquisition of coping strategies.

Adaptation, Psychological↗

PubMed1991

Expression of early genes in light-induced chloroplast differentiation of cultured plant cells.

The objective of this study was to identify genes, preferentially of the plastid, which are rapidly expressed during the initial phase of blue-light-induced chloroplast development in suspension-cultured cells (Chenopodium rubrum L.) and to analyse the encoded proteins. A cDNA library (lambda gt 10) was constructed using total RNA from plastid preparations of dark-grown cells exposed to blue light for 3, 6 and 12 h. By differential screening, at least three clones were identified which correspond to rapidly light-induced plastid genes. For these and a number of nuclear genes represented by other clones, a temporary accumulation of the specific mRNA was observed between 12 and 48 h of blue-light exposure. With regard to their nucleotide sequence and derived amino-acid sequence they seem to represent a novel group of genes distinctive in structure and encoded product.

Amino Acid Sequence↗

PubMed1991

The rat interleukin-5 gene: characterization and expression by retroviral gene transfer and polymerase chain reaction.

The rat interleukin-5 (IL-5) gene was isolated from a genomic lambda phage library and a fragment containing all four exons was inserted into the retroviral vector pXT1, resulting in pXTRIL5. Upon retroviral gene transfer into two IL-5-dependent mouse cell lines, B13 and T88M, autonomously growing cells were established and B-cell growth factor activity was detected in the supernatants of the infected cells. "cDNA" versions of the rat IL-5 gene were rescued by the polymerase chain reaction (PCR) with primers specific for the flanking regions of the cloning site in pXT1. Restriction or DNA sequence analysis of five different clones revealed precise splicing in two cases, while three of the clones had retained the first intron. In addition, in two of these about 400 bp of rat IL-5 5' flanking regions were deleted. The sequence comparison of rat, mouse, and human IL-5 genes revealed a high degree of conservation (e.g., mouse and rat were 92% homologous at the amino acid level). The combination of retroviral gene transfer and PCR may offer an alternative, efficient method for the cloning of cDNAs.

Amino Acid Sequence↗

PubMed1991

Perceived parental rearing and state versus trait aspects of adult depression.

In a pilot study of 72 psychiatric inpatients, relationships between state versus trait aspects of depression and perceived parental rearing have been investigated. It appeared that trait aspects (assessed by the mood scale of the Giessen test) yielded the most frequent and highest correlations with the factors rejection, emotional warmth and overprotection of the EMBU (Egna Minnen av Barndoms Uppfostran--My Memories of Upbringing) questionnaire of parental rearing. Particularly rejecting maternal rearing behaviour during childhood seems to constitute a risk factor for the development of trait depression during adulthood.

Depressive Disorder↗

PubMed1991

[Diagnosis of humidifier lung--comparison of various serologic procedures].

Humidifier lung is a form of exogenous-allergic alveolitis caused by microbial growth in humidifiers and air conditioners. It was the aim of the present study to employ and test the ELISA method as an alternative to antibody determination. 134 employees in a large printhouse equipped with air conditioning plant were examined by us. Specific IgG antibodies against contaminated humidifier fluid were determined by means of a solid-phase radioimmunoassay (protein A RAST) that we had developed further. Alternatively we examined a commercially available ELISA method (Pharmacia IgG-RAST 40; enzyme: beta-galactosidase) and an assay based on protein A peroxidase. The influence of different test conditions was studied. All the methods examined proved suitable for determining the specific IgG antibodies. The commercial beta-galactosidase assay could be adapted to application on microtitre plates in a slightly modified form. In the peroxidase assay it is recommended to use very low serum and enzyme concentrations on account of its high sensitivity. Examination of all the 134 serum samples yielded a high correlation between the results of these two non-radioactive methods and those obtained with the protein-A RAST.

Air Microbiology↗

PubMed1991

Influence of AVOTAN (avoparcin) containing salt licks on the daily weight gain of bulls.

3 group feeding experiments were carried out with the glycopeptide antibiotic avoparcin. Avoparcin was added to salt licks (2.5 g per kg lick stone) and offered to 30 (experiment I), 80 (experiment II), or 20 (experiment III) growing cattle ad libitum over 210, 122, or 281 days. Control animals consumed unsupplemented lick stones. The avoparcin intake amounted to 60 (experiment I), 145 (experiment II), and 100 mg (experiment III) per cattle per day. The daily weight gain increased from 750 to 808 (experiment I), 553 to 649 (experiment II), and from 812 to 822 g per animal per day (experiment III) when avoparcin was added. Avoparcin is a safe feed additive and should be supplemented to various lick stones to improve ruminant performances under tropical rangeland conditions. 15 to 30 mg avoparcin per kg dry matter intake are recommended.

Animals↗

PubMed1991

[Percutaneous drainage of liver and splenic abscess].

42 patients with solitary (n = 34) and multiple (n = 8) abscesses of the liver (n = 36) and the spleen (n = 6) were treated with ultrasound guided percutaneous interventions. 38 patients (90%) underwent a total of 97 closed abscess aspirations using needles of 0.9 and 1.3 mm in diameter. In 4 cases (10%) percutaneous catheter drainage was performed. Intravenous antibiotics were used in all cases. Those patients with closed abscess aspiration additionally received local injection of aminoglycosides into the cavity. 40 out of the 42 patients could be treated successfully by percutaneous methods for a cure rate of 95.2%. Percutaneous drainage failure occurred in 2.4%. One patient with multiple liver abscesses and catheter drainage died from myocardial infarction (hospital mortality 2.4%). Complications of ultrasound-guided interventions included two minor bleedings, requiring no therapy, and one pleural empyema (complication rate 7.1%). There were no treatment related lethal complications. These results indicate that abscesses of the liver and the spleen up to 10 cm in diameter can be effectively treated by closed (repetitive) needle aspiration and antibiotic therapy with a relatively low rate of complications. About half of our patients with abscesses of more than 10 cm received percutaneous catheter drainage. On the basis of our experience surgical drainage of liver abscesses and splenectomy in splenic abscesses should be restricted to those cases with percutaneous drainage failure.

Abscess↗

PubMed1990

Characterization of receptors for glucagon-like peptide-1(7-36)amide on rat lung membranes.

Specific binding of 125I-labelled GLP-1(7-36)amide to rat lung membranes was dependent upon time and temperature and was proportional to membrane protein concentration. Binding was inhibited in a concentration-dependent manner by unlabelled GLP-1(7-36)amide consistent with the presence of a single class of binding sites with a dissociation constant (Kd) of 1.67 +/- 0.29 nmol/l. GLP-1(1-36)amide was 260 times less potent in inhibiting the binding of 125I-labelled GLP-1(7-36)amide to lung membranes (Kd of 448 +/- 93 nmol/l). Vasoactive intestinal polypeptide and peptide-histidine-isoleucine also displaced 125I-labelled GLP-1(7-36)amide from the receptor concentration-dependently; the Kd was 4.31 +/- 0.8 and 7.93 +/- 4.79 nmol/l, respectively. Guanine nucleotides (GTP-gamma-S, GDP-beta-S) decreased the binding of 125I-labelled GLP-1(7-36)amide to rat lung membranes as was found for GLP-1(7-36)amide receptors in RINm5F cells which were also shown to be coupled to the adenylate cyclase system.

Adenylyl Cyclases↗

PubMed1990

Evolutionary aspects, structure, and expression of the rat interleukin 4 gene.

The rat interleukin 4 (IL 4) gene has been isolated from a genomic lambda phage library by cross-hybridization to the mouse IL 4 cDNA. Like the mouse and human counterparts, it exists as a single copy gene in the genome and consists of four exons. The overall structure of the IL 4 locus seems highly conserved. This is indicated by the low degree of restriction fragment length polymorphism in a number of laboratory and wild mice and by the conservation of the intron size between human, rat, and mouse IL 4 genes. Furthermore, evolutionary conserved elements are the promoter region, the position of cysteine residues and sequence motifs in the 3' untranslated regions that are believed to be involved in destabilization of the mRNA. In contrast, the predicted amino acid sequence of the rat IL 4 gene shows low homology (57%) with the mouse homologue. The divergence between mouse and rat IL 4 genes is even more pronounced in the carboxy-terminal region (47% homology in the last 68 amino acids). The ratio between replacement and silent mutations in the IL 4 genes of different species suggests a complex pattern of selective forces acting on the IL 4 gene, which includes both selection against and for amino acid substitutions in individual positions. The functional identity with IL 4 has been confirmed by expression of the gene and the demonstration of the ability to induce MHC class II antigen expression on spleen cells.

Amino Acid Sequence↗

PubMed1990

[The vitamin A supply of laying hens including during rearing. 2. Effect of varied vitamin A supplementation of mixed feed in rearing on production in the laying period].

In six experiments with laying hybrids the influence of a varied nutritive beta-carotene and vitamin A supply during rearing on the performance in the laying period was tested. Basal rations poor in carotene without vitamin A supplementation in the rearing period diminished feed intake and laying performance in the laying period, retarded the beginning of intensive laying and increased feed expenditure per 100 g egg if the feed for laying hens contained less than 5000 IU vitamin A per kg. Relations between varied vitamin A supply and the performance parameters of the laying performance could not be proved if chick and young hen feed with maize even without vitamin A supplement or if rearing feed with approximately 2500 IU vitamin A or laying hen feed greater than 5000 IU vitamin A supply were used.

Analysis of Variance↗

PubMed1990

Interaction of glucagon-like peptide-1 (7-36)amide and cholecystokinin-8 in the endocrine and exocrine rat pancreas.

The synergistic impact of glucagon-like peptide-1 (GLP-1) (7-36)amide and cholecystokinin-8 (CCK-8) was studied in the rat pancreas. The GLP-1 (7-36)amide (1 pM-1 microM) had no effect on the basal or CCK-stimulated (1 nM-1 pM) amylase release from isolated pancreatic acini. The insulinotropic action of 0.5 nM GLP-1 (7-36)amide, which weakly stimulated the glucose-induced (6.7 mM) insulin release from the isolated perfused rat pancreas, was strongly potentiated by the addition of CCK-8 (20, 50, and 100 pM) to the perfusate. In concentrations as they occur physiologically after a meal, CCK-8 alone had no significant effect on basal or glucose-stimulated (6.7 mM) insulin secretion. Our data support the assumption that the nutrient-regulated intestinal release of various peptides represents a regulatory system to ensure an adequate insulin response to food intake, at least in rats.

Amylases↗

PubMed1990

Parental rearing behaviour, family atmosphere and adult depression: a pilot study with psychiatric inpatients.

In a sample of 72 depressed inpatients the relationships between severity of depression, emotional family atmosphere and perceived parental rearing were studied at admission, discharge and follow-up. The results indicate that paternal rejection and overprotection might be of particular importance for developing social skills used to form close relationships, whereas maternal emotional warmth seems to have a preventive effect by promoting emotional stability.

Child↗