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Biomedical subjects

T Berger

Publications and source records attributed to T Berger.

At least 109 records · Page 6Linked to original sources
PubMed1996

Long-term follow-up in cerebral Whipple's disease.

OBJECTIVE: To evaluate the long-term outcome in patients with cerebral Whipple's disease. PATIENTS: We reviewed the literature and contacted authors who had reported on cerebral Whipple's disease within the last 10 years. Fifteen patients were evaluated, including one patient treated at our hospital and the one presented in this paper. The mean observation period was 41 +/- 37 months (minimum 1 month, maximum 120 months). RESULTS: Four patients had improved and were able to pursue an independent lifestyle, three patients had improved but are still dependent on help with simple activities of daily life, one patient was unchanged, and seven patients had died. Patients with initial penicillin alone had a worse prognosis than patients with initial penicillin plus streptomycin. CONCLUSION: Third generation cephalosporins have been shown to be beneficial in cerebral Whipple's disease, therefore initial antibiotic treatment of Whipple's disease should consist of ceftriaxone (instead of penicillin) combined with streptomycin. Since five of 12 patients (40%) treated with co-trimoxazole (trimethoprim plus sulphamethoxazole) did not respond, we conclude that the combination of trimethoprim and sulphamethoxazole does not prevent or cure central nervous system (CNS) involvement in all patients with Whipple's disease. If CNS relapse occurs during treatment with trimethoprim and sulphamethoxazole, oral third generation cephalosporins might be a useful alternative.

Anti-Bacterial Agents↗
PubMed1996

[Clinical aspects and diagnosis of multiple sclerosis].

In this article the clinical aspects and the diagnosis of multiple sclerosis are being reviewed. The first part focuses on the different clinical features, the course of the disease, and the differential diagnosis. The second part discusses the value of the diagnostic methods.

Adult↗
PubMed1995

In vivo fertility of rams in relation to sperm-zona pellucida binding and sperm-zona pellucida penetration of ovine oocytes.

Sperm-zona pellucida (zona) binding and sperm-zona penetration have been suggested for use as in vitro bioassays of fertility since both are essential steps in the fertilization process. The correlations of sperm-zona binding and sperm-zona penetration with the in vivo fertility of sheep were investigated in this study. In vivo fertility was estimated from a heterospermic insemination trial using cryopreserved ram semen. Neither zona binding, zona penetration nor the ability to undergo an acrosome reaction was significantly correlated with the in vivo fertility of the rams (P = 0.78, P = 0.66, and P = 0.85, respectively). These results suggest that the zona binding and zona penetration bioassays may not be useful estimators for assessing cryopreserved ram sperm fertility.

Journal Article↗
PubMed1995

AMPA-type glutamate receptors in glial precursor cells of the rat corpus callosum: ionic and pharmacological properties.

Glial cells in fiber tracts express various functional transmitter receptors, e.g., got glutamate. However, little is known about their biophysical and pharmacological profile. Using the in situ patch-clamp technique, kainate- and AMPA-induced conductance changes of glial precursor cells in the rat corpus callosum were investigated to study these aspects. Precursor cells were identified by their voltage-gated currents and were easily discernable from astrocytes and oligodendrocytes. Kainate induced two overlying effects in these cells: the activation of a cationic current and the block of potassium conductances. Cesium in the pipette solution blocked potassium conductances nearly completely and the ionic profile of the kainate-induced cationic current could be studied in detail. Full replacement of the sodium in the bath by calcium resulted only in a small kainate-induced (calcium) inward current flow, but the kainate-induced outward current carried by Cs+ was less affected reflecting a weak calcium permeability. The kainate response could be blocked by 6,7-dinitroquinoxaline-2,3-dione (DNQX) and millimolar zinc concentrations. Co-application of micromolar concentrations of zinc slightly enhanced the kainate-induced current, while Evans Blue was without any significant effect. Cyclothiazide increased the kainate response by a factor of x6 while concanavalin A did not enlarge it. The AMPA-induced current was amplified by a factor of x39 by cyclothiazide. The present data suggested the expression of weakly calcium-permeable AMPA receptors on glial precursor cells in the rat corpus callosum. Only a small fraction of the agonist-induced current could be seen without the appropriate blockers of receptor desensitization. An additional expression of kainate-preferring glutamate receptors could not be shown.

Animals↗
PubMed1995

Developmental variation of the permeability to Ca2+ of AMPA receptors in presumed hilar glial precursor cells.

Glial cells in the hilus of the dentate gyrus of the rat were investigated using the patch-clamp technique in acute slices of the hippocampal formation. According to their voltage-gated current patterns, two classes of glial cells--putative astrocytes and presumed glial precursor cells--were apparent. The glutamate receptor agonists kainate, glutamate, and alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionate (AMPA) evoked inward currents at a holding potential of -70 mV in astrocytes and presumed glial precursor cells. Inward currents could also be induced in nucleated patches, indicating a direct action on glial receptors. In presumed hilar glial precursor cells, 6,7-dinitroquinoxaline-2,3-dione (DNQX; 10 microM) blocked the kainate-induced current, while it was partially inhibited by Zn2+ (2 mM) and Evans Blue (10 microM). Cyclothiazide (100 microM), in contrast, potentiated this current, indicating the presence of AMPA receptors. In 90% of the presumed glial precursor cells the excitatory amino-acid-evoked current voltage (I/V) relations were linear or outwardly rectifying and reversed close to 0 mV, which is characteristic for non-specific cation channels. To determine the permeability to Ca2+, I/V relations were determined in a Na(+)-free solution containing 40 mM Ca2+ and showed reversal potentials of a wide variation ranging from -63 mV to +1 mV with corresponding PCa/PCs permeability ratios of between 0.09 and 2.10. Statistical analysis revealed that the permeability to Ca2+ significantly decreased with an advance in age (r = -0.596; n = 21; P < 0.01). These data suggest that the Ca2+ influx mediated by the activation of AMPA receptors expressed in presumed hilar glial precursor cells is dependent on the developmental stage.

Animals↗
PubMed1995

Proportion of males with lower fertility spermatozoa estimated from heterospermic insemination.

This study was designed to evaluate the proportion of males with spermatozoa detectably less fertile than the spermatozoa from other males. Previously unpublished and published data from heterospermic trials involving insemination with equal numbers of spermatozoa and resulting in at least 11 offspring from each pair of males were analyzed. The proportion of pairs in which the males sired equivalent numbers of offspring were 0.42, 0.18, 0.33 and 0.09 for trials with fresh boar semen, liquid-stored boar semen, frozen bull semen and fresh rabbit semen, respectively. The calculated proportion of males with less fertile spermatozoa were 0.36, 0.57, 0.42 and 0.70, respectively. Although these differences in fertility would not be apparent in some management systems, a high proportion of ejaculates had spermatozoa that were detectably less fertile.

Journal Article↗
PubMed1995

In vitro fertility evaluation of cryopreserved ram semen and its correlation with relative in vivo fertility.

The present study was designed to evaluate zona-free hamster ova assay conditions for cryopreserved ram semen and to investigate the correlation between ability to penetrate zona-free hamster ova and in vivo fertility. In vivo fertility was estimated for cryopreserved semen from 5 Merino rams using heterospermic insemination. Equal numbers of postthaw motile spermatozoa from a Merino ejaculate and pooled Suffolk ejaculates were mixed prior to insemination. Each Merino ejaculate was paired with the same pool of cryopreserved Suffolk semen. Relative in vivo fertility for each Merino ram was calculated as the proportion of offspring that were sired by the Merino (range 42 to 100%). These ejaculates also differed in their ability to penetrate zona-free-hamster ova (3.6 to 9.0 penetrated spermatozoa per ovum). Differences in penetration rate were correlated with in vivo fertility (P < 0.002, R2 = 0.69). Results of these studies suggest that the zona-free hamster ova bioassay may be a useful test in the assessment of cryopreserved ram sperm fertility.

Journal Article↗
PubMed1995

Identification of porcine sperm plasma membrane proteins that may play a role in sperm-egg fusion.

Sperm plasma membrane (PM) proteins that demonstrate affinity for egg PM preparations have the potential to be biologically important during sperm-egg binding and/or fusion. In this study four such proteins have been identified. To provide quantitative evidence for possible biological function, the large natural variation among different porcine sperm populations with regard to their ability to interact with the egg was compared with the relative binding of egg PM material to individual proteins. An aliquot from each of 24 porcine ejaculates was evaluated by the zona-free hamster ova bioassay and the remainder processed to yield sperm PM vesicles. Aliquots of sperm PM were solubilised, separated by SDS-PAGE, western blotted and probed with partially purified, biotinylated egg PM protein. Bound egg PM proteins were visualised on western blots by an avidin/biotin/horseradish peroxidase system and analysed by scanning laser densitometry. Four sperm PM proteins (62, 39, 27 and 7 kDa estimated molecular mass) were the predominant binders of egg PM. The amount of egg PM bound to the 62 kDa protein was significantly correlated with the ability of sperm from the 24 ejaculates to penetrate zona-free hamster ova (percentage of ova penetrated, p = 0.01, R = 0.65; number of penetrated sperm per ovum, p = 0.02, R = 0.63).

Animals↗
PubMed1995

Developmental regulation of ion channels and receptors on glial cells.

The electrophysiological properties of glial precursor cells and oligodendrocytes were studied in an intact tissue preparation, the corpus callosum slice, with the patch-clamp technique. The pattern of voltage-gated currents exhibited by different cell types in this white matter tract was compared with that from cultured cells of the O-2A lineage. Precursor cells from the in vitro and the in situ preparation were strikingly similar in most aspects. In contrast, oligodendrocytes in the intact tissue differed from their culture correlates and displayed the ability to redistribute excess K+. To study glial transmitter receptors in neuronglial interactions during development, Bergmann glial cells were investigated in a slice preparation of the cerebellum.

Animals↗
PubMed1995

[Increased residual urine volume after local injection of botulinum A toxin].

After major head trauma, a 28-year-old male patient developed tetraparesis with marked left-sided contractions of the leg adductors. Spasticity was resistant to antispastic drugs and intensive physiotherapy. Therefore, we injected 12.5 ng botulinum A toxin (Dysport) in the left adductor longus and adductor magnus. Eight measurements of the post-micturition residual urine of the bladder before botulinum-A-toxin administration gave no evidence for urinary retention. Between day 5 and 14 after injection we measured pathologically increased urinary volumes up to 130 ml at five different points of time. This case report indicates possible subclinical side effects on the autonomic nervous system of the urinary bladder.

Adult↗
PubMed1994

Experimental autoimmune panencephalitis and uveoretinitis transferred to the Lewis rat by T lymphocytes specific for the S100 beta molecule, a calcium binding protein of astroglia.

The pathogenic potential of autoimmune T cell responses to nonmyelin autoantigens was investigated in the Lewis rat using the astrocyte-derived calcium binding protein S100 beta, as a model nonmyelin autoantigen. The Lewis rat mounts a vigorous RT1B1 (major histocompatibility complex class II) restricted autoimmune response to an immunodominant S100 beta epitope (amino acid residues 76-91). The adoptive transfer of S100 beta-specific T cell lines induced a severe inflammatory response in the nervous system, but only minimal neurological dysfunction in naive syngeneic recipients. The inability of S100 beta-specific T cell transfer to induce severe disease was associated with a decreased recruitment of ED1+ macrophages into the central nervous system (CNS) in comparison with that seen in severe experimental autoimmune encephalomyelitis (EAE) induced by the adoptive transfer of myelin basic protein (MBP)-specific T line cells. Moreover, unlike encephalitogenic MBP-specific T cell lines, S100 beta-specific T cell lines exhibited no cytotoxic activity in vitro. Histopathological analysis also revealed striking differences in the distribution of inflammatory lesions in MBP- and S100 beta-specific T cell-mediated disease. In contrast to the MBP paradigm, S100 beta-specific T cell transfer induces intense inflammation not only in the spinal cord, but throughout the entire CNS and also in the uvea and retina of the eye. In view of the distribution of lesions throughout the grey and white matter of the CNS we propose to term this new model experimental autoimmune panencephalomyelitis (EAP) to differentiate it from EAE. These experiments demonstrate for the first time that nonmyelin CNS autoantigens can initiate a pathogenic autoimmune T cell response, although the nature of the target autoantigen profoundly influences the clinical and histopathological characteristics of the resulting autoimmune disease. This is not simply a consequence of the distribution of the autoantigen, as both MBP and S100 beta are coexpressed in many areas of the CNS, but reflects differences in the capacity of different regions of the CNS to process and present specific autoantigens. This new model of T cell-mediated autoimmune CNS disease exhibits a number of similarities to multiple sclerosis (MS), such as its mild clinical course and the involvement of areas of the brain and eye, which are absent in myelin-mediated models of EAE. Nonmyelin autoantigens may therefore play an unexpectedly important role in the immunopathogenesis of inflammatory diseases of the CNS.

Amino Acid Sequence↗
PubMed1994

Evaluation of relative fertility of cryopreserved goat sperm.

This study was designed to compare differences in the in vivo fertility of cryopreserved goat semen assessed by heterospermic insemination with differences in in vitro analyses. Five groups of does were inseminated with mixed frozen-thawed semen from different pairs of bucks. The percentage of offspring sired by each buck in the pair was compared with the relative ability of spermatozoa from that frozen-thawed ejaculate to penetrate zona-free hamster ova, relative post-thaw acrosomal integrity, ability to undergo an acrosome reaction during in vitro capacitation, and assessments of sperm motility. In 4 of the 5 different insemination pairs, the ratio of offspring born was other than 1:1. Acrosomal integrity, ability of spermatozoa to undergo an acrosome reaction, and parameters of sperm motility were not correlated with differences in relative fertility in this experiment using ejaculates from fertile bucks. The ability of spermatozoa to fuse with the oocyte plasma membrane was highly correlated with relative in vivo fertility (R2=0.78, P=0.04). This suggests that fusion with the oocyte plasma membrane is an event in the fertilization process in which significant variation exists among fertile bucks. Assessment of ability of spermatozoa to fuse with zona-free hamster ova may contribute to analysis of post-thaw fertility of frozen-thawed buck semen.

Journal Article↗
PubMed1994

Isolation and partial purification of plasma membrane from porcine oocytes.

Egg plasma membrane (EPM) was isolated in comparatively large amounts from porcine slaughterhouse ovaries. Ovaries were minced, and the oocyte containing fluid was filtered to retrieve zona pellucidae-intact oocytes. The oocytes were homogenized and filtered again to remove zona pellucidae. The egg filtrate was subjected to differential centrifugation to remove membrane bound organelles and the remaining plasma membrane containing material was pelleted by ultracentrifugation. Plasma membranes were further separated from cellular material by sucrose density gradient centrifugation and were collected from portions of the gradient that correspond to the densities of plasma membrane. The purity of isolated plasma membranes was assessed by membrane marker enzyme analysis and transmission electron microscopy. Activities of the plasma membrane marker enzymes 5' nucleotidase and alkaline phosphatase increased from nondetectable levels in the egg filtrate to relatively high levels in the plasma membrane preparation. Marker enzymes for mitochondrial and lysosomal membranes fell from detectable levels in the egg filtrate to levels that were at the lower limits of the assays to detect in the final preparation. Evidence provided by binding of biotin-labeled EPM to capacitated sperm suggests that the isolated EPM retains its biological activity. The procedure presented here represents a novel method of isolating porcine egg plasma membranes for further study involving sperm-egg interaction.

5'-Nucleotidase↗
PubMed1994

Comparison of the ability of progesterone and heat solubilized porcine zona pellucida to initiate the porcine sperm acrosome reaction in vitro.

It has been previously shown that progesterone can initiate the acrosome reaction (AR) of capacitated human and hamster sperm in vivo. We report here that progesterone can initiate a morphologically normal AR in porcine sperm that have undergone capacitation in a Hepes-buffered medium in vitro. In addition, we have compared the abilities of progesterone and heat-solubilized porcine zona pellucida (zona) to initiate the porcine sperm AR. Capacitated porcine sperm were treated with 1 micrograms/ml progesterone, 150 micrograms/ml porcine zona, or solvent control for 10 min. After treatment, sperm were incubated with the supravital dye Hoechst 33258, fixed and the acrosomal status determined in the previously viable sperm by fluorescence microscopy with fluorescein isothiocyanate-labeled Pisum sativum agglutinin (FITC-PSA). There was no significant difference between the percentage of AR initiated by zona compared to that initiated by progesterone. In order to determine whether there was a synergistic interaction between the two AR initiators, both were added simultaneously to capacitated porcine sperm at optimal (1 microgram/ml progesterone, 150 micrograms/ml zona) and suboptimal (75 ng/ml progesterone and 75 micrograms/ml zona) concentrations. Simultaneous addition of the two AR-initiators at the two concentrations stimulated an additive AR-initiating response, rather than a synergistic one. Several possible explanations for the additive results are discussed.

Acrosome↗
PubMed1994

Distribution and morphological characteristics of oligodendrocytes in the rat hippocampus in situ and in vitro: an immunocytochemical study with the monoclonal Rip antibody.

Oligodendrocytes in the rat hippocampus in situ and in organotypic slice cultures were studied by light and electron microscopic immunocytochemistry using the monoclonal Rip antibody. Our results confirm that this antibody exclusively stains oligodendrocytes, while astrocytes and neurons are not labelled. In the light microscope, immunopositive cells had the appearance of myelinating oligodendrocytes with their characteristic tubular processes. In the electron microscope, stained cells showed intimate contacts with myelin sheaths but not with the basal laminae of endothelial cells. Rip-positive oligodendrocytes were unevenly distributed in the adult rat hippocampal formation. In general, they were abundant in layers known to contain many afferent and efferent fibres. In the hippocampus proper, there was a particularly strong immunolabelling of stratum radiatum of field CA2. In the fascia dentata, the hilar region displayed a high cell density, especially in the vicinity of the granule cell layer. A similar distribution of immunopositive cells was found in young animals (15-18 days old); however, the density of labelled cells was lower, particularly in the hilus. Immunolabelled cells in slice cultures of hippocampus displayed the characteristics of myelinating oligodendrocytes. Moreover, they showed an organotypic distribution, although afferent and efferent fibre projections normally myelinated by these cells were absent under these conditions.

Animals↗
PubMed1994

Boar sperm plasma membrane protein profile: Correlation with the zona-free hamster ova bioassay.

This study was designed to compare differences among porcine sperm plasma membrane proteins with the ability of spermatozoa to interact with zona-free hamster ova. Sperm plasma membrane vesicles were recovered from 24 ejaculates from 10 fertile boars, and from cauda epididymal spermatozoa from 3 fertile and 1 very subfertile boar. Solubilized sperm plasma membrane proteins were run on 1D SDS-PAGE gels, transferred to western blots, stained, and analyzed for quantity of protein per band by scanning laser densitometry. Variation in the quantities of individual sperm plasma membrane proteins in the 20 identified bands were statistically compared with the ability of spermatozoa from the same ejaculate to penetrate zona-free hamster ova. The percentages of plasma membrane protein present in 3 bands (90, 84 and 60 kD) were positively correlated with the ability of spermatozoa from the same ejaculate to fuse with zona-free hamster ova (P = 0.002, 0.01, 0.04; R = 0.53, 0.40, 0.38, respectively). The quantities of protein in 2 other bands (69 and 35 kD) were significantly but negatively correlated with the results of the zona-free hamster ova bioassay (P = 0.02, 0.01; R = -0.42, -0.37, respectively). The sperm plasma membrane profiles were quantitatively similar between the ejaculated samples and the fertile epididymal samples. Six epididymal sperm plasma membrane proteins were present in statistically different quantities in the subfertile boar sample and the 3 fertile controls. The 90 kD band positively correlated with the hamster ova bioassay in the ejaculated samples was not detected in the subfertile epididymal sperm plasma membrane sample. These results suggest that protein(s) in one or more of the 3 positively correlated ejaculated sperm plasma membrane protein bands may be involved in sperm-oocyte interaction.

Journal Article↗
PubMed1994

Olfactory function in patients with hypogonadotropic hypogonadism: an all-or-none phenomenon?

Hypogonadotropic hypogonadism (HH) refers to an endocrine defect of hypothalamic origin resulting in gonadal hypoplasia and frequently associated with anosmia or severely impaired olfactory function (Kallmann's syndrome). This apparently results from a disruption in the migration of neurons from the olfactory placode to the bulb and hypothalamus early in development, and so provides a unique opportunity to investigate olfactory function in human subjects with congenitally incomplete peripheral systems. Olfactory performance in 37 HH patients and 37 age-matched controls was compared using a modified version of the Munich Olfaction Test. This test is based on the sniff-bottle method and includes tests of (i) odor quality discrimination, (ii) intensity discrimination, (iii) detection thresholds, and (iv) recognition, hedonic evaluation and identification ability. The patients could be divided into two distinct groups differing significantly on all four subtests and showing no overlap in performance: 20 anosmics, conforming to Kallmann's syndrome, and 17 apparent normosmics whose performance was slightly poorer, but not significantly different to that of the controls. The unexpected failure to find a continuum of olfactory dysfunction now raises the question whether HH with or without anosmia represents two syndromes with distinct etiologies, or rather reflects the ability of the olfactory system to function well despite morphological impairment.

Adult↗