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Biomedical subjects

C Köhler

Publications and source records attributed to C Köhler.

At least 91 records · Page 5Linked to original sources
PubMed1989

Norfloxacin versus trimethoprim-sulfamethoxazole. A study in patients with known bacteriuria undergoing transurethral resection of the prostate.

Three hundred and forty-three patients with suspected bacteriuria undergoing transurethral resection of the prostate (TUR-P) were randomized to treatment with either trimethoprim-sulfamethoxazole (TMP-SMX) or norfloxacin (NF) for 5 1/2 days beginning the evening prior to operation. It was possible to analyse 165 patients for efficacy. Elimination of bacteria on days 10 to 20 was achieved in 78.1% and 78.3% in the TMP-SMX and NF group, respectively. The accumulated elimination rates for the follow up period (days 10-42) were 68.5% for the TMP-SMX group and 76.2% for the NF group. The differences were not statistically significant. No patient had any clinical signs of upper urinary tract infection or septicemia. Three hundred and twelve patients were analysed for safety. Twenty-six patients reported 32 adverse drug events (ADEs). Four reactions in the TMP-SMX group were considered severe while in the NF group all the ADEs were of mild or moderate intensity. In this study NF seems to be at least as effective and safe as TMP-SMX.

Aged↗
PubMed1989

[The sprue behavior of nonprecious metals].

As a base for single crowns and bridge anchors the individual casted construction combined with the manufactured root post offers undisputed advantages. At casting silver-palladium alloys, the root posts possibly may change the characteristic properties of their material. The casting reactions of sipal with cylindrical pins made of pure titanium (EMO Ti110) and root posts with adhesion head made of implant steel (URX2CrNiMoN18.12(0] was investigated. Interstice-free castings of sipal to pin from implant steel and titanium can be demonstrated by means of pictures of metallographic (grinding) specimens investigated by light- and electron-beam microscopy. The casting quality is identified mainly by selection of the embedding mass, the rise of the preheating temperature and period of preheating.

Crowns↗
PubMed1989

[Optimization of surgical tooth preservation using a fully ready-made post implant construction system for endodontic implantation].

By individual cast constructions necessary for endodontic implantations the cold-formed post material (pure titanium/implant steel) has to be heat-treated by recasting (Sipal as construction material). Therewith are connected structure changes with distinct worsening of the material properties. By means of the potentiodynamic anodic polarization it can be proved that the silver-palladium alloy is the component with the highest susceptibility to corrosion. A suitable alternative to the individual cast construction is a fully ready-made implant construction system made from pure titanium which can solve the problems of bond, corrosion and strength.

Crowns↗
PubMed1989

[Extracorporeal lithotripsy of gallbladder calculi with piezoelectrically generated shock waves: initial experiences].

A piezoelectric lithotripter ("Piezolith 2300") was used in 24 patients for extracorporeal fragmentation of radiolucent gallbladder stones. In 19 patients with one stone and 4 patients with two stones (diameter: 0.8-3.1 cm) fragmentation to a maximal fragment size of 7 mm was achieved. One to three treatment sessions were necessary (mean 1.5). During adjuvant oral litholytic therapy with chenodeoxycholic acid and ursodeoxycholic acid (500 mg each daily up to 80 kg bodyweight and 750 mg in patients with more than 80 kg bodyweight) 4 patients came to be completely free of stones within a mean follow-up time of 15 weeks. Treatment was well tolerated by all patients, no analgesia or sedation was needed. Side effects were cutaneous petechiae in two patients, microscopic haematuria in two others and leucocyturia in another. We conclude that lithotripsy of gallbladder stones can be performed safely and effectively not only by the established underwater spark discharge type of lithotripter but also by the piezoelectric system.

Adult↗
PubMed1988

Cholecystokinin-octapeptide (CCK-8) receptors in the hippocampal region: a comparative in vitro autoradiographic study in the rat, monkey and the postmortem human brain.

Quantitative in vitro receptor autoradiography of 125I-CCK-8 was used to study the regional distribution of CCK-8 receptors in the primate hippocampal region. In the monkey, specific 125I-CCK-8 binding sites were enriched in layer 2 of the presubiculum, layers 1, 2, and 4 of the entorhinal area and in the inner two-thirds of the molecular layer of the area dentata. Moderate to low densities were detected in layer 3 of the entorhinal area, the deep layers of the presubiculum, all layers of subiculum and subfields CA1 and CA3 of Ammon's horn. In the human brain, the highest densities of 125I-CCK-8 binding sites were detected in layer 2 of the presubiculum and layer 2 of the lateral entorhinal area. Moderate to low levels were detected in the Ammon's horn and area dentata. This pattern of receptor distribution overlaps only partly with that found in the rat and indicates phylogenetic differences in the localization of CCK-8 receptors within the hippocampal region.

Aged↗
PubMed1988

Intrinsic connections of the retrohippocampal region in the rat brain: III. The lateral entorhinal area.

This paper describes the retrohippocampal projections of individual layers of the lateral entorhinal area as studied by the method of anterograde transport of the lectin Phaseolus vulgaris leucoagglutinin (PHA-L) in the rat. As in the medial entorhinal area (EA), (Köhler, '86a) PHA-L injections restricted to individual layers of the lateral EA resulted in labeling of sparse projections to the subicular complex (e.g., subiculum, pre- and parasubiculum), whereas projections to the perirhinal area and piriform cortex were prominent. All PHA-L injections resulted in the labeling of axons projecting longitudinally within the entorhinal area, in both dorsal and ventral directions, albeit the ventral projections were the most prominent ones. PHA-L injections into layers 2a and 2b resulted in labeling of axons that could be followed into layers 2a, 2b, and layer 1 on both sides of the injection site. Whereas numerous axons appeared to terminate in layer 2, most fibers ascended into layer 1, where they ran in a medial direction, passing the medial EA, around the parasubiculum to the presubiculum. Numerous axons were found to take a lateral route running past the lateral aspect of the lateral EA to the piriform cortex. The axons running medial in layer 2 did not enter the medial EA. After PHA-L injections into layer 3, a large number of axons left the labeled cells on both sides of the injection site, in addition to massive projections that ascended into layers 2b, 2a and 1, just above the injection. Few axons entered layers 2-6 of the medial EA, but numerous axons innervated layer 1, where they were found to run in the outer half of this layer. The axons running in a medial direction reached layer 1 of the presubiculum, whereas the laterally oriented ones innervated the molecular layer of the piriform cortex. PHA-L injections into layer 4 resulted in massive labeling of projections to all superficially located layers. Layers 1, and 2b through 5 were innervated lateral to, and layer 4 medial to, the injection site. After a PHA-L injection into layer 5, ascending projections were found innervating layers 1 through 4. The terminal fields were found to be particularly dense in the deep parts of layer 3 and in layer 1. This projection expanded laterally, but few projections reached into the medial sector of the lateral EA or into the medial EA.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1988

Immunohistochemical localization of cytochrome P-450 in the rat brain.

Immunohistochemical localization of cytochrome P-450 in the brains of normal untreated male rats has been demonstrated with polyclonal antibodies raised against hepatic P-450C. These antibodies recognize P-450C and D, two closely related forms of P-450. We have identified P-450C,D immunoreactivity (P-450C,D-i) within both neurons and glial cells. Neuronal cell bodies showing P-450C,D-i were present in several forebrain areas, including the olfactory bulb, the caudate nucleus, the cingulate, the frontal and the entorhinal cortex, the hippocampus and the thalamus. In the brainstem, P-450C,D-i neurons were detected in the substantia nigra, the nucleus locus coeruleus, raphe nucleus, reticular formation and the trigeminal nerve nucleus and the dorsal motor nucleus of the vagus. Glial cells containing P-450C,D-i were situated within myelinated fiber tracts in the forebrain (e.g. the corpus callosum, the internal capsule) and the brainstem (e.g. the superior cerebellar peduncle, the medial longitudinal fasciculus). Some, but not all, of the P-450C,D-i glial cells also stained with an antibody against glial fibrillary acidic protein. The present findings represent the first immunohistochemical demonstration of cytochrome P-450 in the brain and suggest that cytochrome P-450C,D is constitutive in neurons and glial cells of most brain regions throughout the rat neuraxis.

Animals↗
PubMed1988

Immunohistochemical identification of quinolinic acid phosphoribosyltransferase in glial cultures from rat brain.

Glial cell cultures were shown to contain 3 identifiable classes of cells which could be specifically stained with antibodies directed against quinolinic acid phosphoribosyltransferase (QPRT), the catabolic enzyme of the endogenous excitotoxin quinolinic acid. Some, but not all, QPRT-positive cells also contained glial fibrillary acidic protein. These cultures may constitute an in vitro system in which cerebral quinolinic acid metabolism and function can be examined.

Animals↗
PubMed1988

In vivo labelling of rat brain dopamine D-2 receptors. Stereoselective blockade by the D-2 antagonist raclopride and its enantiomer of 3H-spiperone, 3H-N,N-propylnorapomorphine and 3H-raclopride binding in the rat brain.

The stereospecific blockade by raclopride and FLB472 (the R enantiomer of raclopride) of the specific in vivo binding of [3H]-spiperone, [3H]-N,N-propylnorapomorphine (NPA) and [3H]-raclopride was studied in seven brain regions (e.g., caudate nucleus, olfactory tubercle, septum, hippocampus, frontal cortex, substantia nigra, pituitary gland) of the male albino rat. The binding of all three ligands was dose-dependently blocked by raclopride and FLB472. The blockade by FLB472 occurred at doses 50-100 times higher than that obtained by raclopride. The maximal blockade by raclopride of [3H]-spiperone binding differed between brain areas. Thus, the largest blockade was obtained in the substantia nigra (95%), septum (90%), caudate nucleus (60%) and olfactory tubercle (60%), while the blockade of [3H]-spiperone binding in the frontal cortex and pituitary gland did not exceed 30% and 50%, respectively. In contrast to [3H]-spiperone, the in vivo binding of [3H]-NPA and [3H]-raclopride was prevented by 90-100% in all brain areas examined. Taken together, the present findings indicate that the in vivo binding of three radioactive ligands to a central dopamine D-2 receptor can be stereoselectively blocked by the enantiomers of raclopride. The findings suggest that, under in vivo conditions, [3H]-raclopride and [3H]-NPA may label a closely related receptor site. However only some of the [3H]-spiperone binding sites may be identical to the [3H]-raclopride binding sites. The findings indicate furthermore that the relative overlap of D-2 sites shared by [3H]-spiperone and [3H]-raclopride may vary between brain regions.

Animals↗
PubMed1988

Raclopride, a new selective ligand for the dopamine-D2 receptors.

1. The use of raclopride, a new compound of the salicylamide series, as a ligand for the labelling of dopamine-D2 receptors in vitro and in vivo is described. 2. 3H-Raclopride has a high affinity for the dopamine-D2 receptors (Kd = 1 nM in rat striatum) with much less affinity for any other receptor. 3. 3H-Raclopride enters the brain easily and has therefore also been used in in vivo binding and autoradiography. The nonspecific binding is very low both in vitro and in vivo. 4. Raclopride has been labelled with 11C, and is used as a marker for dopamine-D2 receptors in the living human brain using positron emission tomography.

Animals↗
PubMed1988

Localization of quinolinic acid metabolizing enzymes in the rat brain. Immunohistochemical studies using antibodies to 3-hydroxyanthranilic acid oxygenase and quinolinic acid phosphoribosyltransferase.

Specific antibodies raised in rabbits against 3-hydroxyanthranilic acid oxygenase (EC 1.13.11.6) and quinolinic acid phosphoribosyltransferase (EC 1.13.11.6) and quinolinic acid phosphoribosyltransferase (EC 2.4.2.19) were used in immunohistochemical studies to map the cellular localization of the quinolinic acid metabolizing enzymes in the adult male rat brain. 3-Hydroxyanthranilic acid oxygenase immunoreactivity was found to be present in glial cells of presumed astroglial identity, as judged by co-localization with glial fibrillary acidic protein. 3-Hydroxyanthranilic acid oxygenase-immunoreactive glial cells were present in all brain regions and within major fiber tracts. The density of 3-hydroxyanthranilic acid oxygenase-immunoreactive glial cells as well as the intensity of staining of these cells differed among brain regions. In general, telencephalic acid diencephalic areas harbored a larger number of 3-hydroxyanthranilic acid oxygenase-positive cells than did mesencephalic regions. In the former regions the caudate nucleus, septum, nucleus accumbens, neocortex and hippocampus were particularly enriched in 3-hydroxyanthranilic acid oxygenase-immunoreactive cells. In the thalamus, regional differences were noted with regard to the intensity of staining among glial cells with high densities of 3-hydroxyanthranilic acid oxygenase cells in the anteroventral, reticular and ventromedial nuclei. In the inferior and superior colliculi, numerous 3-hydroxyanthranilic acid oxygenase-positive glial cells were found in all layers. In the hypothalamus, 3-hydroxyanthranilic acid oxygenase-immunoreactive glial cells were encountered in the zona incerta, the lateral hypothalamic area, the caudal preoptic region and in the dorsomedial nucleus. In the mesencephalon, the substantia nigra contained numerous, moderately stained cells. At caudal levels of the brain-stem, a relatively large number of cells was detected in the nucleus of the solitary tract, the pontine nucleus and in the fascial nerve nucleus, while other nuclei, such as the reticular formation and the area postrema were relatively poor in 3-hydroxyanthranilic acid oxygenase-immunoreactive cells. In addition to staining of glial cells, neuronal cell bodies containing 3-hydroxyanthranilic acid oxygenase immunoreactivity were detected in the main and in the accessory olfactory bulb, as well as in the ventromedial nucleus of the hypothalamus. Quinolinic acid phosphoribosyltransferase immunoreactivity was observed within glial cells and in association with neuronal cell bodies. Some, but not all, quinolinic acid phosphoribosyltransferase positive glial cells contained glial fibrillary acidic protein (Köhl

3-Hydroxyanthranilate 3,4-Dioxygenase↗
PubMed1988

Regional distribution of cytochrome P-450 in the rat brain: spectral quantitation and contribution of P-450b,e, and P-450c,d.

The cytochrome P-450 (P-450) content of different regions of the rat brain was measured after partial purification of the enzyme from homogenates, and the quantitative contribution of P-450b,e and P-450c,d to brain P-450 was assessed by Western immunoblotting and immunohistochemistry using rabbit antibodies raised against purified hepatic P-450b and P-450c, respectively). P-450 could be quantitated by its reduced CO difference spectrum after chromatography of homogenates on p-chloroamphetamine-coupled Sepharose. The yield of P-450 from whole brain was 90 +/- 19 pmol/g of tissue, which is approximately 1% of the level in liver microsomes from control rats. The amount of P-450 recovered from homogenates of olfactory lobes, hypothalamus, thalamus, striatum, cerebral cortex, and brainstem varied between 40 and 100 pmol/g of tissue. The cerebellum was a region of exceptionally high P-450 content, with yields of up to 400 pmol/g whereas the substantia nigra yielded only 16-20 pmol/g. Immunohistochemical studies with anti-P-450b and anti-P-450c revealed intense staining of a limited number of cells in the cerebellum with both antibodies and in the thalamus only with anti-P-450c. In the cerebellum, both anti-P-450b and anti-P-450c stained the Bergmann glial cells together with their radial processes. Individual glial cells in the granular cell layer were also stained. There was no staining of Purkinje cells. In the thalamus, anti-P-450b gave weak staining of certain astroglia, but with anti-P-450c, there was intense staining of neuronal somata.(ABSTRACT TRUNCATED AT 250 WORDS)

7-Alkoxycoumarin O-Dealkylase↗
PubMed1988

Quinolinic acid metabolism in the rat brain. Immunohistochemical identification of 3-hydroxyanthranilic acid oxygenase and quinolinic acid phosphoribosyltransferase in the hippocampal region.

Quinolinic acid (QUIN) is a potent endogenous excitotoxin, which has been shown to be present in the brain (Wolfensberger et al., 1983). In order to study the cellular localization of QUIN metabolism in the hippocampus, specific antibodies raised against purified rat liver 3-hydroxyanthranilic acid oxygenase (3HAO) and quinolinic acid phosphoribosyltransferase (QPRT), the enzymes directly responsible for QUIN synthesis and catabolism, respectively, were used for immunohistochemical studies in the adult male rat. Cells containing 3HAO immunoreactivity (3HAO-i) were present in all subfields of the hippocampal region, including the area dentata, Ammon's horn, the subicular complex, and the entorhinal area. The highest density of 3HAO-i cells was found in the molecular layer of Ammon's horn and in the hilus of area dentata, while the granular cell layer of area dentata and stratum pyramidale of Ammon's horn contained the lowest number of 3HAO-stained cells. A majority of hippocampal 3HAO-i cells were also stained with monoclonal antibodies against glial fibrillary acidic protein (GFAP) or S-100 protein, suggesting that 3HAO-i is present primarily in astrocytes. At the ultrastructural level, 3HAO-i was found to be distributed uniformly throughout the cytoplasm, with intense immunostaining present in the internal and the external layers of the mitochondria. QPRT-i was detected in 3 morphologically distinct cell types present in all parts of the hippocampus. The total number of QPRT-i cells was lower than that of the 3HAO-i cells. QPRT-i cells were relatively numerous in the molecular and radial layers of Ammon's horn, while they occurred only sporadically in stratum pyramidale of Ammon's horn and in the granular cell layer of area dentata. Many QPRT-i cells stained with antibodies against GFAP and S-100, but the proportion of cells in which QPRT was colocalized with these glial marker proteins was lower than that for 3-HAO-i cells. At the ultrastructural level, 2 types of QPRT-i glial cells were detected. The smaller cell type had a diffuse cytoplasmic staining, while the larger cell type, which also contained glial filaments, showed diffuse cytoplasmic staining and intense staining of lysosomal structures. The observation that 3HAO and QPRT only partially coexist in hippocampal glial cells suggests that while synthesis and catabolism of QUIN may occur in the same glial cells, catabolism of QUIN can also take place in cells lacking the synthetic enzyme.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1987

Morphological analysis of the tuberomammillary nucleus in the rat brain: delineation of subgroups with antibody against L-histidine decarboxylase as a marker.

With an antibody specific for L-histidine decarboxylase (HD) in combination with immunohistochemical techniques and retrograde fluorescent tracing, the morphology, distribution, and projections of the histaminergic neurons of the posterior hypothalamus were studied in the adult male rat. Magnocellular neurons, situated on both sides of the mammillary recess and close to the ventral surface of the brain rostral and caudal to the mammillary bodies, were found to contain HD-immunoreactivity (HD-i). In addition to these magnocellular neurons, a substantial number of small and medium-sized neurons were immunostained, as were strands of cells of all sizes bridging the HD-i cell groups. A detailed mapping of the HD-i cells in frontal, sagittal, and horizontal sections showed that these neurons make up one continuous cell group, defined as the tuberomammillary nucleus (TM). This nucleus can be divided into several subgroups. Thus, approximately 600 HD-i neurons situated on each side of the mammillary recess compose the medial subgroup of the TM (TMM). The ventral subgroup of the TM (TMV) consists of some 1,500 neurons situated at the ventral surface of the brain, rostral (TMVr) and caudal (TMVc) to the mammillary bodies. The TMM contains a greater proportion of parvicellular neurons compared to the TMV. About 100 HD-i cells are scattered within the lateral hypothalamic area, the posterior hypothalamic region, the perifornical area, the supramammillary nucleus, and the dorsomedial hypothalamic nucleus. These cells are collectively named the diffuse part of the TM (TMdiff). The morphological differences between the TMM and the TMV did not signal differences in the efferent connections of these subgroups. Thus, single injections of the fluorescent tracer Fast Blue into different regions of the brain, including the spinal cord, resulted in retrograde labeling of HD-i neurons, which were distributed throughout the TM with no discernible topographic pattern. More specifically, each subgroup of the TM contributed projections innervating or passing through a large number of brain regions, including the olfactory bulb, hippocampus, caudate nucleus, paraventricular and supraoptic nuclei of the hypothalamus, cerebellum, tectum, medulla, and spinal cord. The widespread projections of the HD-i neurons contrasted to the more specific projections observed from non HD-i neurons in cell groups situated around the TM. Taken together, these findings suggest that the HD-i cells of the posterior hypothalamus constitute one major nucleus, the TM, and that this nucleus may be subdivided into three components, each of which has diffuse projections throughout the neuraxis.

Animals↗
PubMed1987

Co-localization of neuropeptide tyrosine and somatostatin immunoreactivity in neurons of individual subfields of the rat hippocampal region.

The co-localization of neuropeptide tyrosine (NPY) and somatostatin (SOM) in rat hippocampal cells was studied in double labelling experiments using a combination of antibodies against the two peptides on the same tissue section. The individual hippocampal subfields show large variations in the relative number of NPY- and SOM-immunoreactive (-i) neurons. While the entorhinal area is far richer in SOM as compared to NPY-i cells, NPY-i cells predominate in all subfields (e.g. regio superior, regio inferior) of Ammon's horn. Co-localization of both peptides in single neurons was highest in regio inferior and in the area dentata and lowest in the retrohippocampal structures. In the dorsal hippocampus, the number of SOM-i cells containing NPY-i was higher than the number of NPY-i cells containing SOM-i. This pattern was reversed in the retrohippocampal region. At ventral levels the incidence of colocalization of NPY- and SOM-i in single cells increased in all hippocampal subfields.

Animals↗
PubMed1987

Distribution of neurotensin receptors in the primate hippocampal region: a quantitative autoradiographic study in the monkey and the postmortem human brain.

The distribution of [3H]neurotensin ([3H]NT) binding sites in the monkey and the postmortem human brain was studied by using quantitative in vitro receptor autoradiography. Biochemical experiments carried out on tissue sections of the monkey hippocampus showed that the binding of [3H]NT was saturable, reversible and of high specificity. The hippocampal [3H]NT binding was displaced by fragment NT 8-13 but not fragment NT 1-8 of the peptide. The anatomical analysis showed a highly heterogeneous distribution of [3H]NT binding sites within both the monkey and the human hippocampal region. In both species the highest density of [3H]NT binding sites was found in the presubiculum (rank order of binding density: layer 2 greater than 6 greater than 1 greater than 3, 4, 5 in both monkey and man) and the entorhinal area (monkey: layer 4 greater than 6 greater than 5 greater than 1 greater than 2 greater than 3; human: layer 1 = 2 greater than 5 greater than 3). The subiculum and Ammon's horn were relatively poor in [3H]NT binding sites in both species. In the area dentata the highest density of [3H]NT binding sites was found in the hilar region.

Animals↗
PubMed1987

Distribution of neuropeptide Y receptors in the rat hippocampal region.

The distribution of binding sites for neuropeptide Y (NPY) was studied in the rat hippocampal region by using [3H]NPY together with quantitative in vitro receptor autoradiography. The highest density of specifically bound [3H]NPY was found in regio superior and regio inferior of Ammon's horn. Within these fields, stratum oriens, stratum pyramidale and stratum radiatum harboured the highest densities of [3H]NPY binding while stratum moleculare was relatively poor in [3H]NPY binding sites. In area dentata, the highest density of [3H]NPY binding was found in the inner one third of the molecular layer. In the presubiculum and in the entorhinal area, the outer two layers were slightly more enriched in [3H]NPY binding sites than were the deep layers. In all hippocampal subfields a clear gradient of increased [3H]NPY binding was found at successively more ventral levels.

Animals↗