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Biomedical subjects

R Maurer

Publications and source records attributed to R Maurer.

At least 109 records · Page 6Linked to original sources
PubMed1986

[Abdominal inflammatory pseudotumor (plasma cell granuloma) with anemia and hypergammaglobulinemia].

Intraabdominal pseudotumor of the plasma cell granuloma type in a 19-year-old man is reported. The patient presented with fever and weight loss lasting months, and the laboratory findings revealed high sedimentation rate, hypochromic, microcytic anemia, thrombocytosis, elevated alkaline phosphatase, decreased thromboplastin time and polyclonal hypergammaglobulinemia. When the plasma cell granuloma was removed, all laboratory findings returned to normal within 3 months and the patient remained asymptomatic during the two-year follow-up.

Adult↗
PubMed1986

Cat scratch disease: evidence for a bacterial etiology. A retrospective analysis using the Warthin-Starry stain.

97 cases of acute necrotizing granulomatous lymphadenitis (so called "reticulozytärabszedierende Lymphadenitis") were examined retrospectively with the Warthin-Starry stain, in order to detect bacteria in patients with cat-scratch disease (CSD). 27 patients with CSD were found and among those, bacteria were demonstrated in 4. The organisms were pleomorphic rods of about 3 micron length and occurred in clumps within foci of fresh necrosis. We found the organisms in a much lower percentage than has been described in the literature. The reasons may be that many of our patients had antimicrobial treatment prior to the biopsy and that step-sectioning of the specimen may be necessary in order to detect fresh lesions. Our findings seem to confirm the observation that CSD may have a bacterial aetiology.

Bacteria↗
PubMed1986

Different ionic requirements for somatostatin receptor subpopulations in the brain.

Two populations of brain somatostatin (SS) receptors, one with high affinity for the somatostatin octapeptide analogue SMS 201-995 (SS1 type) and one poorly sensitive to this analogue (SS2 type) have been characterised in regard to their ionic requirements using two radioligands, the iodinated Tyr3 derivative of the octapeptide SS analog SMS 201-995 and the iodinated [Tyr11]-SS. Specific binding of 125I-[Tyr11]-SS to rat cortex membrane homogenates can be increased by approximately 180% in presence of 5 mM Mg2+. The increase in number of binding sites seen by Mg2+ is not accompanied by a marked increase in affinity for SS but for SMS 201-995: the low affinity binding for SMS 201-995 seen in absence of Mg2+ is replaced in part by higher affinity binding in presence of these ions. SMS 201-995 sensitive SS1 receptor subpopulation measured with 125I-204-090, a specific ligand for SS1 subpopulation, is massively increased in presence of Mg2+. However, SMS 201-995 insensitive SS2 receptor population measured with 125I-[Tyr11]-SS in presence of excess SMS 201-995 is unchanged in presence of Mg2+. The Mg2+-dependency can also be observed with autoradiography for extra cortical, i.e. hippocampal, brain SS receptors. 120 mM Na+ does not affect the total brain SS receptor population, but reduces the specific binding of SS1 receptors and increases that of SS2 receptors. Therefore, the rat brain, in particular the cortex, possesses a SMS 201-995-sensitive, Mg2+-dependent SS receptor subpopulation (SS1) as well as a SMS 201-995-insensitive, Mg2+-independent SS population (SS2).

Animals↗
PubMed1986

Somatostatin receptors in the adrenal.

Somatostatin receptors have been visualized in the adrenal by autoradiography using the iodinated Tyr3 derivative of the somatostatin octapeptide analog SMS 201-995 (H-D-Phe-Cys-Phe-D-Trp-Lys-Thr-Cys-Thr(ol), Sandostatin*). In the rat adrenal gland somatostatin receptors are not exclusively restricted to the glomerulosa cell layer, but can also be found in the adrenal medulla, particularly after in vitro incubation. The receptor sites in the adrenal are saturable and have affinity constants of 0.42 nM in the adrenal cortical and 0.15 nM in medullary membranes. The distribution of somatostatin receptors in the adrenal visualized in vitro is strongly species specific. Whereas only the adrenal medulla is labelled in the hamster, mouse and rhesus monkey, solely the glomerulosa layer shows somatostatin receptor sites in the cow and the guinea pig. The rat is the only species with a high density of somatostatin receptor sites in both the glomerulosa cell layer and the adrenal medulla.

Adrenal Cortex↗
PubMed1986

Distribution of somatostatin receptors in the human brain: an autoradiographic study.

High affinity somatostatin receptors have been measured in postmortem brains from 18 neurologically asymptomatic patients (mean age: 67 years) using the stable somatostatin analog 125I-204-090, DPhe-Cys-Tyr-DTrp-Lys-Thr-Cys-Thr(ol), as radioligand. In homogenates from human frontal cortex, high affinity (Kd = 0.52 nM; Bmax = 557 fmol/mg protein) receptors with pharmacological specificity for somatostatin, [D-Trp8]somatostatin and somatostatin-28 were found. The CNS distribution of these receptors was studied by autoradiography. Somatostatin receptors were distributed in varying densities throughout the whole brain. High concentrations are found in all cortical layers, the deeper layers (V-VI) being usually more dense than the superficial layers (I-III). The limbic system is heavily labeled, in particular hippocampus (CA1, dentate gyrus), most of the nuclei of the amygdala, and the habenula. Also parts of the basal ganglia are very rich in somatostatin receptors: the nucleus caudatus as well as the nucleus accumbens are very dense, whereas the globus pallidus is virtually unlabeled. Interestingly, significant amounts of somatostatin receptors are found in the human cerebellum, which is devoid of endogenous somatostatin. Other discrete areas of the CNS are enriched with somatostatin receptors: locus coeruleus, tuberal nuclei of the hypothalamus, claustum, tuberculum olfactorium as well as spinal trigeminal nucleus and substantia gelatinosa of the spinal cord. The substantia innominata is poor in somatostatin receptors. In general there is a good correlation in the distribution of somatostatin receptors in the human and rat brain and there is a reasonable correlation with endogenous somatostatin levels in human brain tissue, particularly in the larger structures. The very high density and the specific localization of somatostatin receptors in strategic key points in the CNS such as cortex, basal ganglia, limbic system and substantia gelatinosa suggests an important role of somatostatin in cognitive, sensory and extrapyramidal motor functions. The significance of somatostatin receptors in the human cerebellum remains to be elucidated.

Aged↗
PubMed1986

Distribution of opioid binding sites in the guinea pig hippocampus as compared to the rat: a quantitative analysis.

In vitro autoradiography of cryostat sections revealed major differences between the distribution of opioid binding sites in the hippocampus of the guinea pig and the rat. Only very low binding was found in the pyramidal cell layer, the dentate granular cell layer and the commissural-associational zone of the dentate molecular layer of the guinea pig, whereas these areas were moderately to densely labeled in the rat. In the guinea pig an enrichment of sites was observed in the terminal field of the mossy fiber system in the hilus which was absent in the rat. Binding sites in the guinea pig were found to be mainly of the kappa and mu type. The distribution of [Leu]enkephalin immunoreactivity does not correlate well with the distribution of delta opioid binding sites in the hippocampus. Quantification of opioid binding sites in the hippocampus demonstrates that no one type of site can be assigned to a specific hippocampal subregion nor does the intensity or the pattern of distribution of binding types agree well with the distribution of endogenous opioid peptides.

Animals↗
PubMed1986

Isolation of cDNA clones for differentially expressed genes of the human parasite Schistosoma mansoni.

Little is known about the mechanisms that control transformations during the life cycle of Schistosoma mansoni. To enable isolation of DNA sequences encoding developmentally regulated antigens a cDNA expression library in the vector lambda gt11 amp3 was constructed from adult mRNA and immunologically screened with sera from infected individuals. We report here on the properties of three recombinant clones that derive from developmentally regulated genes. Clone 10-3 encoded a beta-galactosidase fusion protein present in high abundance in infected Escherichia coli. Clones 7-2 and 8-2 also produced immunologically recognized proteins; however, the peptides did not appear to be beta-galactosidase fusion proteins. The expression of mRNAs hybridizing to these cDNAs was examined in the different stages of the parasite life cycle. Messenger RNA corresponding to clone 10-3, approximately equal to 1000 bases in length, was present in higher abundance in male worms than in females but was not detected in schistosome eggs. A 900-base mRNA hybridizing to clone 7-2 was observed in adult worms and eggs. Both clone 10-3 and clone 7-2 hybridized to smaller mRNAs in cercariae and freshly transformed schistosomula than in adult worms. Clone 8-2 contained tandem cDNA inserts. One cDNA hybridized to a 1700-base mRNA present in all stages, while the second hybridized to an 800-base mRNA specific to adult female worms.

Animals↗
PubMed1986

Interaction of DNA polymerase III gamma and beta subunits in vivo in Salmonella typhimurium.

We show that temperature-sensitive mutations in dnaZ, the gene for the gamma subunit of DNA polymerase III holoenzyme, can be suppressed by mutations in the dnaN gene, which encodes the beta subunit. These results support a direct physical interaction of these two subunits during polymerase assembly or function. The suppressor phenotype is also sensitive to modulation by the dnaA genotype. Since dnaA is organized in an operon with dnaN, and dnaA is a regulatory gene of this operon, we propose that the dnaA effect on suppression can best be explained by modulation of suppressor dnaN levels.

Cloning, Molecular↗
PubMed1986

Lymph-node infarction and malignant lymphoma: a multicentre survey of European, English and American cases.

A multicentre study of 51 cases of lymph-node infarction seen in the 30-year period 1956 to 1985 was conducted in order to assess both the short- and long-term prognostic implications of the condition. In 14 cases malignant lymphoma was found synchronously with the infarct. Of the remaining 37 patients with apparently 'benign' lymph-node infarction only six showed manifestations of malignant lymphoma in the follow-up time studied (mean = 48 months; range 1-156 months). These subsequent malignant lymphomas all occurred within 2 years of the lymph-node infarction. A postal enquiry and collation of other cases in the medical literature indicates that a minority (26 of 81) have developed malignant lymphoma, and that these lymphomas, too, have all appeared within 2 years. Thorough examination of both the infarcted lymph nodes and others resected at the same time is mandatory in order to exclude concomitant or underlying malignant lymphoma. Two years after lymph-node infarction the risk of malignant lymphoma is negligible.

Adolescent↗
PubMed1986

High incidence of somatostatin receptors in human meningiomas: biochemical characterization.

Thirteen human meningiomas were tested for their content of specific somatostatin (SRIH) receptors using an in vitro binding assay with meningioma homogenates as well as receptor autoradiography. All tumors had measurable amounts of somatostatin receptors. Receptor density, however, greatly varied among the tumors, ranging from low levels to more than 400 fmol/mg protein. Seven tumors, biochemically characterized in detail, had saturable and high affinity receptors [mean Kd, 1.10 +/- 0.42 (+/- SEM) nM], with pharmacological specificity for SRIH resembling the noncentral nervous system type of SRIH receptor. There was no correlation between the density of SRIH receptors and the density of progestin receptors measured in parallel. The presence of SRIH receptors in meningiomas was completely unexpected, and their role unknown. If the receptors can mediate antiproliferative properties in meningiomas, as has been suggested to be the case for such receptors in other endocrine tumors, the present data could be of potential therapeutic interest.

Adult↗
PubMed1986

Chemistry and pharmacology of SMS 201-995, a long-acting octapeptide analogue of somatostatin.

Starting from a hypothetical conformation of natural somatostatin and a knowledge of the minimal fragment needed for biological activity, a process of rational design and lead optimization has led to the potent, selective, and long-acting analogue SMS 201-995, (formula: see text) which selectively inhibits growth hormone secretion in several animal species for up to 6 h after subcutaneous application. In the rat, SMS inhibits GH, insulin, and glucagon 70, 3, and 23 times more potently than SRIF, resulting in GH/insulin and GH/glucagon selectivities of 20 and 3, respectively. The compound has been shown to inhibit growth of transplantable insulinomas in hamsters and to label selectively a subset of somatostatin receptors in the rat cortex. A radioactively labelled analogue has been used to visualize somatostatin receptors in a GRF-secreting human tumour. The stability and duration of action of SMS 201-995 after subcutaneous injection enable for the first time extended investigations of the clinical utility of somatostatin in various diseases.

Animals↗
PubMed1986

Problems of cyclosporine localization in the renal tissue.

The aim of the present investigation was to localize cyclosporine (CSA) in the rat kidney. The experimental approaches included autoradiography after i.v. injection of 3H-CSA, immunofluorescence after i.v. injection of fluorochrome labeled CSA and immunohistochemistry using the rabbit-alpha-CSA antibody. It was not possible to localize CSA in specific structures of the rat kidney. Finally, immunohistochemistry of human renal tissue gave only an unspecific staining of proximal tubular cells, which was lost when the antibody was absorbed on renal tissue homogenate. In vitro binding of 3H-CSA on renal homogenate indicated only unspecific absorption of the highly lipophilic compound; no specific binding was detected on cytosolic renal fractions. The failure to demonstrate CSA in tubular or arteriolar lesions might have been due to the fact that the affinity of binding is too low for detection, or that CSA does not accumulate within these structures.

Animals↗
PubMed1985

[Heterosexual transmission of the acquired immunodeficiency syndrome (AIDS)].

A man who, only in 1979 and on a few occasions, had homosexual contacts, transmitted AIDS virus HTLV-III in 1980 and 1981 to two previously healthy women who did not belong to any AIDS risk group. One of them now has an early form of AIDS, while the other died of AIDS in its full form and her child, born in 1983, has fairly far progressed early symptoms of AIDS. Serum antibodies against HTLV-III were demonstrated in all four subjects.

Acquired Immunodeficiency Syndrome↗
PubMed1985

Brain somatostatin receptor subpopulation visualized by autoradiography.

[125I-Tyr11]somatostatin-14 as well as iodinated D-Tyr1 and Tyr3 derivatives of the cyclic octapeptide somatostatin analog, SMS 201-995 (H-D-Phe-Cys-Phe-D-Trp-Lys-Thr-Cys-Thr-ol) have been used as radioligands for somatostatin receptor autoradiography in rat brain. Although the cyclic octapeptide ligands label the majority of the regions labeled with [125I-Tyr11]somatostatin, in the cortex and hippocampus only a subpopulation of somatostatin receptors is labeled. Cyclic octapeptide ligands have improved resolution due to their very low non-specific binding.

Animals↗
PubMed1985

beta-Adrenoceptor subtypes in sections of rat and guinea-pig kidney.

The present autoradiographical study examines the distribution of the two beta-adrenoceptor subtypes in sections of rat and guinea-pig kidney. The radioligand [125Iodo]-(--)-cyanopindolol was used for the labelling of beta-adrenoceptors and the selective beta-adrenoceptor blocking agents ICI 89-406 (beta 1-antagonist) and ICI 118-551 (beta 2-antagonist) were utilized to differentiate both subclasses unequivocally. beta-Adrenoceptors in rat kidney were found to be almost exclusively beta 1. They were located mainly on glomeruli and to a lesser extent on the straight part of the distal tubules and on the cortical portion of the collecting ducts. Some beta 2-adrenoceptors were localized around the corticomedullary junction. Grain localization in the auto-radiograms was absent in the inner medulla and papilla. Glomeruli and distal tubules of the guinea-pig kidney also possess only beta 1-adrenoceptors, but, in contrast to the rat, extremely high concentrations of beta 2-adrenoceptors were associated with the straight part of the proximal tubules in the cortex and possibly with the cortical portion of the collecting duct. Labelling was not detected on the proximal convoluted tubule in either species.

Adenylyl Cyclases↗