Biomedical subjects

J Grosse

Publications and source records attributed to J Grosse.

At least 37 records · Page 2Linked to original sources

PubMed2000

Synaptosome-associated protein of 25 kilodaltons in oocytes and steroid-producing cells of rat and human ovary: molecular analysis and regulation by gonadotropins.

The synaptosome-associated protein of 25 kDa (SNAP-25) is crucially involved in exocytosis in neurons. The aim of this study was to investigate whether it is present in the ovary. We found SNAP-25 to be expressed in nonneuronal cells of the rat and human ovary, namely in all oocytes and in steroidogenic cells, including granulosa cells (GC) of large antral follicles and luteal cells. Both isoforms, SNAP-25a and b, were found in the ovary. Oocytes obtained by laser capture microdissection were shown to express SNAP-25b, whereas SNAP-25a was found in rat GC and human luteinized GC. Immunohistochemical observations of strong SNAP-25 staining in GC of large growing antral follicles compared with absent or weak staining in small follicles suggested a role in folliculogenesis. To study a presumed regulation of SNAP-25, we used a rat GC line (GFSHR-17), which expresses FSH receptors, and luteinizing human GC, which express LH receptors. FSH elevated SNAP-25 mRNA and protein levels about fivefold within 24 h in GFSHR-17 cells. The cAMP analogue dibutyryl-cAMP (db-cAMP) mimicked this action of FSH. The effects of both db-cAMP and FSH were inhibited by the protein kinase A (PKA) inhibitor H89. In contrast, SNAP-25 protein and mRNA-levels were not altered by LH/hCG in luteinized human GC. Our results for the first time identify SNAP-25b in oocytes and SNAP-25a in steroidogenic cells of the mammalian ovary. SNAP-25a and b may be involved in different exocytotic processes in these cell types.

Animals↗

PubMed2000

Molecular and prognostic classification of advanced melanoma: a multi-marker microcontamination assay of peripheral blood stem cells.

The presence or absence of melanoma cells in human peripheral blood has recently been shown to be associated with disease prognosis, including overall survival. The detection of tyrosinase mRNA-positive circulating melanoma cells by reverse transcription-polymerase chain reaction (RT-PCR) has been limited to disseminated tumours expressing measurable amounts of this melanocyte-specific enzyme. To biologically classify both melanotic and amelanotic melanomas and to evaluate the clinical and prognostic relevance of tumour cell microcontamination, we examined autologous peripheral blood stem cell (PBSC) harvests from patients with advanced malignant melanoma prior to dose-escalated chemotherapy. To assay heterogeneous melanoma cell antigen expression, we developed a highly sensitive RT-PCR using four melanoma- and one tumour-associated antigen as molecular markers. Expression of the melanocyte-associated transcripts of tyrosinase, MART1/Melan-A, tyrosinase-related protein-1 (TRP-1) and tyrosinase-related protein-2 (TRP-2) as well as the tumour-specific transcript of MAGE-3 was analysed by RT-PCR in PBSC harvests from 31 patients. Seven of the 31 PBSC harvests tested positive for one or more molecular markers: two patients for tyrosinase only, and one patient for MAGE-3 only, one patient for tyrosinase and MAGE-3, one for tyrosinase and MART1/Melan-A, and two patients for tyrosinase, MART1/Melan-A, TRP-2 and MAGE-3. mRNA-positive patients exhibited a significantly impaired overall survival (P = 0.0032), with a median survival of 3 months as opposed to 10 months in PBSC mRNA-negative patients. In conclusion, the use of this multiple-marker microcontamination assay allowed for molecular and prognostic classification of advanced malignant melanoma.

Adult↗

PubMed2000

Abnormalities of the photoreceptor-bipolar cell synapse in a substrain of C57BL/10 mice.

PURPOSE: A preferential loss of ERG b-wave was detected in a substrain of C57BL/10 mice. Electroretinographic and histologic techniques were used to investigate this hitherto unknown retinopathy. METHODS: ERGs were obtained from normal and affected C57BL/10. C57BL/6 mice served also as controls. a-Wave and c-wave analyses were performed. Microscopic investigations were done at two different ages. RESULTS: In the scotopic ERG, a severe reduction of the b-wave amplitude could be observed, whereas the a-wave was only moderately attenuated ("negative ERG"). With age, the a-wave amplitude further decreased, but the rate of reduction was comparable to normals. Oscillatory potentials were severely altered, and the photopic ERG was absent. The ERG c-wave was comparable to normal. ERG a-wave analysis also revealed a reduced maximum amplitude, but no significant difference of receptor sensitivity. Light microscopy revealed a thinning of all retinal layers but mostly of the outer plexiform layer. The number of photoreceptor nuclei was reduced by one third. Electron microscopy revealed a profound loss of ribbon-shaped synapses between rod and rod-bipolar cells and severely abnormal ribbons in the case of cones. CONCLUSIONS: The so-called negative ERG was associated with alterations in the synaptic layer between rods and rod bipolars. The absent cone ERG may be due to the altered cone-on-bipolar synapses. The overall thinning of the retina as well as the moderately reduced scotopic a-wave amplitude remain unexplained.

Animals↗

PubMed1999

SNAP-25 requirement for dendritic growth of hippocampal neurons.

Structure and dimension of the dendritic arbor are important determinants of information processing by the nerve cell, but mechanisms and molecules involved in dendritic growth are essentially unknown. We investigated early mechanisms of dendritic growth using mouse fetal hippocampal neurons in primary culture, which form processes during the first week in vitro. We detected a key component of regulated exocytosis, SNAP-25 (synaptosomal associated protein of 25 kDa), in axons and axonal terminals as well as in dendrites identified by the occurrence of the dendritic markers transferrin receptor and MAP2. Selective inactivation of SNAP-25 by botulinum neurotoxin A (BoNTA) resulted in inhibition of axonal growth and of vesicle recycling in axonal terminals. In addition, dendritic growth of hippocampal pyramidal and granule neurons was significantly inhibited by BoNTA. In contrast, cleavage of synaptobrevin by tetanus toxin had an effect on neither axonal nor dendritic growth. Our observations indicate that SNAP-25, but not synaptobrevin, is involved in constitutive axonal growth and dendrite formation by hippocampal neurons.

Animals↗

PubMed1999

Introduction to the application of capillary gas chromatography of performance-enhancing drugs in doping control.

Performance-enhancing drugs banned by antidoping rules are detected in doping control preferably by hyphenated chromatographic techniques, capillary gas chromatography in particular. Based on the prohibited classes of substances and on the general aspects of sample collection and preparation, a survey is given about the usual procedures of screening, identification and confirmation of the most important doping agents: stimulants, narcotics, anabolics, diuretics, beta-blockers. In addition to gas chromatography itself, the application of various MS techniques doping is outlined.

Adrenergic beta-Antagonists↗

PubMed1999

Transient entrainment of a circadian pacemaker during development by dopaminergic activation in Syrian hamsters.

Maternal cues entrain a circadian pacemaker in fetal Syrian hamsters. These cues may act through dopaminergic activation of the fetal suprachiasmatic nucleus (SCN); injection of the dopamine D1 agonist SKF38393 to pregnant hamsters entrains activity rhythms of their pups and induces expression of c-fos in the fetal SCN. The aim of this study was to examine the ability of SKF38393 to entrain neonatal Syrian hamsters and to determine the age at which this effect is lost. SKF38393 injections given to two groups of pups at opposite times of day on postnatal days (PN) 1-5 entrained the pups' activity rhythms to average phases that differed by 9.25 h. SKF38393 failed to establish different average phases when given on PN 6-10. Injection of SKF38393 on PN 1, but not PN 6, induced expression of Fos. These results demonstrate that dopaminergic activation is a potent entraining stimulus in neonatal hamsters and that its entraining effects, as well as its ability to induce Fos, are lost by PN 6. The phase established by dopaminergic activation was approximately opposite to that previously shown to be established by melatonin injections. Dopaminergic activation and melatonin may mimic separate but complementary maternal entraining signals which represent day and night.

2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-ben↗

PubMed1999

Bioavailability of trospium chloride after intravesical instillation in patients with neurogenic lower urinary tract dysfunction: A pilot study.

Oral drug treatment of detrusor overactivity often causes undesirable side effects in other organs. For some patients, in particular those with neurogenically induced detrusor overactivity (detrusor hyperreflexia), the tolerance level for adverse effects is low and oral treatment may become ineffective. Intravesical administration of the drug can diminish the side effects or increase treatment effectivity in patients who are (partially) refractory to oral treatment because the relative concentration of the drug is increased in the target organ and decreased in the circulation. Six men (19-34 years old) with traumatic spinal cord lesions between C2 and Th11 were randomized to intravesical instillation with 15 or 30 mg trospium chloride in 40 ml saline into the empty bladder. Catheterization was postponed until at least 3 h after instillation, and fluid intake was not allowed during the first 4 h. Blood samples were taken before and 11 times after instillation; the last sample 12 h post instillation. Four positive samples were found in three patients: 0.10 ng/ml after 1 h and 0.13 ng/ml after 2(1/2) h in two patients with 15 mg, and 0.24 ng/ml after 30 min and 0.70 ng/ml after 6 h in one patient with 30 mg instilled trospium chloride. Three adverse effects were reported and were rated as probably not related to the drug. It is concluded that intravesically instilled trospium chloride is not absorbed into the circulation in significant amounts and, thus, it may be expected that this mode of administration will improve the efficacy of trospium chloride therapy by reducing the side effects. Neurourol. Urodynam. 18:447-453, 1999.

Adult↗

PubMed1998

Melatonin entrains the restored circadian activity rhythms of syrian hamsters bearing fetal suprachiasmatic nucleus grafts.

A circadian pacemaker consists of at least three essential features: the ability to generate circadian oscillations, an output signal, and the ability to be entrained by external signals. In rodents, ablation of the suprachiasmatic nucleus (SCN) results in the loss of circadian rhythms in activity. Rhythmicity can be restored by transplanting fetal SCN into the brain of the lesioned animal, demonstrating the first two of the essential pacemaker features within the grafts. External signals, such as the light/dark cycle, have not, however, been shown to entrain the restored rhythms. Melatonin injections are an effective entraining stimulus in fetal and neonatal Syrian hamsters of the same developmental ages used to provide donor tissue for transplantation. Therefore, melatonin was used to test the hypothesis that SCN grafts contain an entrainable pacemaker. Daily injections of melatonin were given to SCN-lesioned hosts beginning on the day after transplantation of fetal SCN. Two groups that received melatonin at different times of day 12 hr apart each showed significantly clustered phases but with average phases that differed by 8.67 hr. Thus melatonin was able to entrain the restored circadian activity rhythms. In contrast to these initial injections, injections given 6 weeks after transplantation were unable to entrain or phase shift the rhythms. The results demonstrate that SCN grafts contain an entrainable circadian pacemaker. In addition, the results also indicate that the fetal SCN is directly sensitive to melatonin and, as with intact hamsters, sensitivity to melatonin is lost during SCN development.

Animals↗

PubMed1998

Prenatal hippocampal granule cells in primary cell culture form mossy fiber boutons at pyramidal cell dendrites.

Mossy fiber boutons are the sites of synaptic signalling between hippocampal granule and pyramidal neurons. We studied the formation and localization of these terminals during development of prenatal hippocampal neurons in primary culture. Using the synaptic vesicle membrane proteins synaptophysin and synaptoporin as markers we observed that both proteins were mainly localized in perikarya and processes of fetal hippocampal neurons during the first days in vitro (DIV). Following DIV 6 synaptophysin was present in small terminals. After DIV 20 in addition large terminals immunoreactive for synaptophysin and synaptoporin were found, which were identified by electron microscopy as mossy fiber boutons impinging on pyramidal neuron dendrites. Synaptic vesicles and endosomes in the mossy fiber boutons were labeled when incubated with exogenous horseradish peroxidase, indicating that they were competent for exo-endocytosis. Taken together, our data show that hippocampal granule neurons grown in dissociated primary cultures form mossy fiber boutons containing synaptophysin and synaptoporin at pyramidal cell dendrites. Since the composition and the characteristic morphology of mossy fiber boutons formed in vitro is the same as observed in vivo we conclude that their development follows an intrinsic program.

Animals↗

PubMed1998

Loss of VLA-3 (CD49c/CD29) expression in two multidrug resistant Burkitt's lymphoma cell lines.

Expression of P-glycoprotein (P-gp) mediated multidrug resistance (MDR) has been suggested to be associated with an impaired clinical outcome in several malignancies. In contrast to P-gp itself, further phenotypical and functional alterations related to MDR are poorly characterized. In this in vitro study, we analyzed two Burkitt's lymphoma cell lines (Raji and Daudi) for the beta 1 integrin phenotype prior to and after induction of MDR via co-cultivation with vincristine. A significant loss of the VLA-3 (CD49c/CD29) adhesion receptor was observed whereas all other intergins analyzed lacked considerable changes. We conclude that induction of P-gp mediated MDR does not only affect resistance to cytotoxic drugs but also induces cellular changes with potential relevance for migratory and/or adhesive properties of malignant cells.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed1998

Elevated plasma levels of interleukin-1 receptor antagonist are associated with decreased cellular BCL-2 oncoprotein expression in B-chronic lymphocytic leukemia.

Plasma IL-1Ra levels and cellular BCL-2 oncoprotein expression were measured in a total of forty blood samples obtained from twenty-eight B-CLL patients and four healthy subjects. High IL-1Ra plasma levels (as defined by mean + three times standard deviation of normal controls) were observed in eleven samples (ten patients) which showed a significantly decreased cellular expression of BCL-2 protein (14.7 +/- 16.3% of cells as determined by immunofluorescence) when compared to B-CLL samples with no elevated IL-1Ra (BCL-2, 31.0 +/- 18.6%; p < or = 0.0115). Albeit correlational only, our results may encourage further experiments to elucidate potential regulatory effects of IL-1Ra for cellular BCL-2 oncoprotein expression.

Adult↗

PubMed1997

Detection of melanoma cells in peripheral blood stem cell harvests of patients with progressive metastatic malignant melanoma.

The detection of melanocyte-specific messenger RNA in patients with malignant melanoma suggests the potential contamination of peripheral blood stem cell (PBSC) harvests by neoplastic cells. In this study, the melanocyte-specific transcripts of tyrosinase and Melan-A/MART-1 were used to detect neoplastic cells in PBSC harvests of nine metastatic malignant melanoma patients. Only one patient's PBSC harvest tested positive for tyrosinase. All harvests were negative for Melan-A/MART-1. Our results suggest that contamination of PBSC harvests with neoplastic cells may not contribute to disease progression following high-dose chemotherapy in advanced malignant melanoma.

Adult↗

PubMed1996

Peripheral blood tyrosinase messenger RNA detection and survival in malignant melanoma.

BACKGROUND: The most widely accepted criteria for the evaluation of prognosis of malignant melanoma are histopathologic and clinical presentation. No currently available laboratory tests provide additional prognostic information. It has recently been suggested that reverse transcription and polymerase chain reaction (RT-PCR)-based detection of tyrosinase messenger RNA (mRNA) in peripheral blood might be useful in the early detection of circulating tumor cells, since tyrosinase is thought to be a melanocyte-specific marker. PURPOSE: To further evaluate the clinical relevance of this potential marker, we examined peripheral blood samples from patients with malignant melanoma in different stages of disease for the presence of tyrosinase mRNA. METHODS: Total cellular RNA was extracted from heparinized peripheral blood cells from 64 patients with malignant melanoma, from five healthy control subjects, and from four patients with other cancers using the RNAzol A method. For analysis of tyrosinase mRNA, RT-PCR was performed as previously described by Smith et al.; the sensitivity of this assay was tested using RNA extracted from human melanoma cells (SK-mel 1 and SK-mel 3 cell lines) serially diluted with peripheral blood obtained from healthy control subjects. Two additional human melanoma cell lines (SK-mel 30 and RPMI-7951) served as positive controls for RT-PCR detection of tyrosinase mRNA. Overall patient survival curves were constructed using Kaplan-Meier estimates. RESULTS: Tyrosinase mRNA was detected by RT-PCR assay of all four of the established melanoma cell lines tested. Nine of the 64 patients with malignant melanoma were found to have detectable tyrosinase mRNA in their peripheral blood cells (tyrosinase-positive patients). The 16 patients with localized primary melanoma did not have detectable tyrosinase mRNA in their peripheral blood cells. Among the 48 patients with metastatic disease, all 27 patients who exhibited no evidence of disease progression were tyrosinase negative. Notably, all nine tyrosinase-positive patients had visceral metastases and were found to exhibit disease progression at the time of the sampling. Four of the nine tyrosinase-positive patients were also found to test negative at times without evidence of progressive disease; one patient became negative after achieving stable disease and three became positive for tyrosinase transcripts on disease progression. The probability of survival from time of sampling was significantly lower in the nine tyrosinase-positive patients when tested versus the 23 patients with comparable disease but without detectable tyrosinase mRNA (two-sided; P < or = .05). CONCLUSIONS: The results of this study demonstrate that the detection of tyrosinase mRNA in cells in the peripheral blood by RT-PCR may be a useful prognostic marker for predicting tumor progression and poor clinical outcome in patients with malignant melanoma.

Adult↗

PubMed1996

Entrainment of Syrian hamster circadian activity rhythms by neonatal melatonin injections.

The circadian rhythms of fetal and neonatal rodents are entrained by their mother. This entrainment is dependent upon the maternal suprachiasmatic nucleus (SCN), but the mechanism of entrainment is unknown. Administration of the pineal hormone melatonin to pregnant, SCN-lesioned female Syrian hamsters entrains the activity rhythms of their hamster pups. The aim of this study was to determine whether melatonin injected directly in neonatal Syrian hamsters is able to entrain circadian rhythms and, if so, for how long this effect persists during development. Injection of melatonin in two groups of hamster pups at opposite phases on postnatal days 1-5 entrained the onset of activity rhythms on the day of weaning to two phases 10.67 h apart. Melatonin injection did not entrain activity rhythms to opposite phases on either postnatal days 6-10 or 21-25. Vehicle injection did not entrain animals to opposite phases at any of the ages studied. These results demonstrate that melatonin is able to act directly on the neonate to cause entrainment and that this effect disappears after postnatal day 6.

Animals↗

PubMed1996

A role for the circadian clock of the suprachiasmatic nuclei in the interpretation of serial melatonin signals in the Syrian hamster.

Seasonal rhythms of reproduction in the Syrian hamster are triggered by the pineal hormone melatonin. By varying the parameters of systemic infusions of exogenous melatonin delivered to pinealectomized hamsters, it has been shown that the hypothalamus is sensitive to the duration of individual signals, which serve as an inverse coding of day length. It also has been shown that animals are sensitive to the temporal structure of a series of signals insofar as a series of melatonin infusions of appropriate number and duration may fail to invoke a gonadal response if they are presented at inappropriate frequencies. Although the endogenous circadian pacemaker of the suprachiasmatic nucleus (SCN) is not thought to be involved in the measurement of or response to melatonin signal duration, its contribution to the interpretation of a series of melatonin signals remains to be determined. Syrian hamsters are able to show a short-day-like gonadal response to a series of melatonin signals delivered on a variety of noncircadian schedules, including one in which a "random" pattern of infusions is employed. This study investigated the role of the SCN in the interpretation of such infusion paradigms. Adult male Syrian hamsters received electrolytic lesions of the SCN. Pinealectomized, lesioned, and intact hamsters then were infused with melatonin or saline at one of three different phases of the day in a random pattern such that no signal was predictive of the timing of the next. Other lesioned and intact animals received melatonin or saline at the same time daily. After 6 weeks, control saline-infused animals in both lesioned and intact groups had large testes. However, sham animals receiving melatonin in the random infusion pattern had regressed testes, as did the lesioned animals receiving melatonin at the same phase every day. By contrast, lesioned animals that received melatonin in the random pattern of infusion did not show a short-day gonadal response. These results suggest that although the SCN is not necessary for measurement of the duration of individual signals, it may play a role in the interpretation of a series of melatonin signals in which the number of melatonin signals and the period of time over which they are encountered need to be compared.

Animals↗

PubMed1996

Exposure to vinblastine modulates beta 1 integrin expression and in vitro binding to extracellular matrix molecules in a human renal carcinoma cell line.

Solitary stroma-invading tumor cells expressing the ATP-binding cassette transporter P-glycoprotein have been reported to be associated with a significantly higher incidence of vessel invasion and lymph node metastases. In contrast to P-gp-mediated multidrug resistance (MDR) which has become well characterized over the last decade, little is known about further morphological and functional alterations in drug-resistant tumor cells. Binding of malignant cells to components of the extracellular matrix mediated by beta 1 integrins has been suggested to play a substantial role in the metastatic cascade. We studied alterations of beta 1 integrin expression and in vitro adhesiveness to extracellular matrix proteins of the human renal carcinoma line Caki-1 in comparison to the vinblastine resistant sublines Caki-1/V1 and Caki-1/V10 (cultured in the presence of 1 ng/ml and 10 ng/ml vinblastine, respectively). Both VLA-1 and VLA-2 receptors were acquired by the Caki-1/V10 subline, whereas untreated and Caki-1/VI cells lacked surface expression of these antigens. VLA-6 was found to be decreased in the vinblastine-resistant sublines. Attachment of drug-resistant Caki-1/V1 and Caki-1/V10 cells to collagen type I was significantly increased when compared to parental cells (p < or = 0.005). Significant differences in the attachment to type IV collagen were observed between Caki-1/V10 and untreated cells (p < or = 0.045). Both Caki-1/V1 and Caki-1/ V10 cells exhibited increased adhesion to fibronectin when compared to cells of the untreated line (p < or = 0.04). Whether an aberrant expression of beta 1 integrin receptors in resistant cells in combination with altered tumor cell adhesiveness is caused by MDR induction or whether it is an epiphenomenon of cytotoxic stress is unknown. Future studies will be needed to characterize the clinical relevance of MDR-associated changes in tumor cells.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed1995

Chromatographic techniques--the basis of doping control.

The principal definition of doping, the groups of banned compounds and the basic analytical problems and strategy of doping analysis are outlined, and the position of chromatography in doping analysis is explained. Examples of the application of GC-MS, especially high-resolution MS. and of LC-thermospray MS to doping problems are given. A practical case is presented briefly, showing the post-analytical problem of evaluating even unequivocal results.

Anabolic Agents↗

PubMed1995

Immediate-early genes and the neural bases of photic and non-photic entrainment.

The expression of immediate-early genes (IEGs) within the mammalian suprachiasmatic nucleus (SCN) identifies individual light-responsive cells of the circadian system. Cells immunoreactive for products of IEGs form a neurochemically heterogeneous population, of which a few are VIP (vasoactive intestinal peptide)-immunoreactive or GRP (gastrin-releasing peptide)-immunoreactive, although the phenotypes of most of the others have yet to be determined. Dual-labelling experiments with anatomical tracers reveal that only a minority of efferent projection neurons of the SCN are immunoreactive for IEG products, and it is likely that the majority of the immunoreactive cells are interneurons or glia. Photic induction of IEGs is mediated via NMDA (N-methyl-D-aspartate) and non-NMDA glutamatergic receptors, the SCN expressing a topographically specific complement of subtypes of the NMDA receptor. Non-photic cues (arousal) can shift the clock but this is not associated with expression of IEGs, demonstrating that the proteins encoded by IEGs are probably involved in transducing photic cues, rather than shifting the clock per se. Their induction provides an anatomically explicit marker for circadian phase and photic sensitivity and so is useful in analyses of circadian function, for example, in the tau mutant hamster. Non-photic phase shifts are accompanied by adrenocortical activation, confirming the importance of arousal in shifting of the clock. The phase-shifting effect of arousal can be blocked by treatment with the serotonin receptor antagonist ketanserin, suggesting that ascending serotonergic input to the forebrain, possibly directly to the SCN, is an important mediator of entrainment by arousal.

Animals↗