Synergistic interaction of two independent genetic loci causes extreme elevation of serum IgA in mice

Understanding the molecular regulation of immunoglobulin A (IgA) expression is important as it plays an essential role in the first-line defence through mucosal secretions. Using inbred mouse strains, we identified two independent and dominant acting genetic loci that synergistically cause a 40-fold upregulation in serum IgA levels when introduced into the murine strain C57Bl/6J (B6). The first locus on chromosome 12 appears to be mainly responsible for the natural four-fold higher IgA levels in C3HeB/FeJ (C3H) compared to B6 mice. A second independent, chemically induced mutation on chromosome 5 caused a two-fold elevation when transferred from C3H into B6 mice. Both loci in concert effect a 40-fold elevation against the B6 genetic background. We determined the chromosomal localization of the two loci simultaneously by a one-step mapping process. The chemically induced mutation was identified within the immunoglobulin joining chain (IgJ) gene on chromosome 5. The major serum IgA modifier between the C3H and B6 was located on chromosome 12. This modifier region was mapped to a 350 kb region containing several immunoglobulin heavy-chain genes and the Ig alpha germline switch gene. We speculate that by interfering with both IgA expression and distribution, synergistic regulation of IgA is achieved.

Axonal sorting of Kir3.3 defines a GABA-containing neuron in the CA3 region of rodent hippocampus

Hippocampal interneurons comprise a heterogeneous group of locally acting GABAergic neurons. In addition to their variability in cotransmitter content and receptor profile, they express a variety of potassium channels that specify their individual properties. Here we describe a new type of large GABA-containing neuron in rodent hippocampus that is characterized by an axonal sorting of the potassium channel Kir3.3. The parent cell bodies of the Kir3.3-positive axons are located in CA3, as assessed by primary cultures derived from hippocampal subareas. At postnatal day 14 these neurons appear at the border between stratum oriens and stratum pyramidale of CA3, from where their axons pass through stratum pyramidale to join the mossy fiber tract. In adult hippocampus, high levels of Kir3.3 channel protein exist in axons that run with the mossy fiber tract. Kir3.3 and the vesicular GABA transporter could be identified in subpopulations of large synaptic terminals that probably derive from Kir3.3 neurons. Axonal sorting of Kir3.3 appears to be typical of a group of large inhibitory neurons, including Purkinje cells and a novel type of interneuron in CA3. Kir3.3 neurons might modulate the activity of CA3 circuitries and consequently memory processing in the hippocampus.

A novel missense mutation in the mouse growth hormone gene causes semidominant dwarfism, hyperghrelinemia, and obesity

The SMA1-mouse is a novel ethyl-nitroso-urea (ENU)-induced mouse mutant that carries an a-->g missense mutation in exon 5 of the GH gene, which translates to a D167G amino acid exchange in the mature protein. Mice carrying the mutation are characterized by dwarfism, predominantly due to the reduction (sma1/+) or absence (sma1/sma1) of the GH-mediated peripubertal growth spurt, with sma1/+ mice displaying a less pronounced phenotype. All genotypes are viable and fertile, and the mode of inheritance is in accordance with a semidominant Mendelian trait. Adult SMA1 mice accumulate excessive amounts of sc and visceral fat in the presence of elevated plasma ghrelin levels, possibly reflecting altered energy partitioning. Our results suggest impaired storage and/or secretion of pituitary GH in mutants, resulting in reduced pituitary GH and reduced GH-stimulated IGF-1 expression. Generation and identification of the SMA1 mouse exemplifies the power of the combination of random mouse mutagenesis with a highly detailed phenotype-analysis as a successful strategy for the detection and analysis of novel gene-function relationships.

A mouse model for cystinuria type I

Cystinuria, one of the most common inborn errors of metabolism in humans, accounts for 1-2% of all cases of renal lithiasis. It is caused by defects in the heterodimeric transporter system rBAT/b0,+AT, which lead to reduced reabsorption of cystine and dibasic amino acids through the epithelial cells of the renal tubules and the intestine. In an N-ethyl-N-nitrosourea mutagenesis screen for recessive mutations we identified a mutant mouse with elevated concentrations of lysine, arginine and ornithine in urine, displaying the clinical syndrome of urolithiasis and its complications. Positional cloning of the causative mutation identified a missense mutation in the solute carrier family 3 member 1 gene (Slc3a1) leading to an amino acid exchange D140G in the extracellular domain of the rBAT protein. The mouse model mimics the aetiology and clinical manifestations of human cystinuria type I, and is suitable for the study of its pathophysiology as well as the evaluation of therapeutic and metaphylactic approaches.

Interleukin-12 inhibits apoptosis in chronic lymphatic leukemia (CLL) B cells

The purpose of the present study was to investigate the effect of interleukin-12 on apoptosis of chronic lymphatic leukemia (CLL) B cells. Apoptotic indices were determined in highly purified CD5(+) B lymphocytes isolated from peripheral blood of seven patients with histologically confirmed CLL. Interleukin-4 as a known inhibitor of apoptosis was used as control. Quantitative analysis of apoptosis was determined by cell death detection ELISA. Our findings indicate that interleukin-12 inhibits ex vivo apoptosis in a large proportion of B-CLL patients and may be closely involved in the pathogenesis of disease. Therefore, our results may help identify potential new therapeutic targets in this malignancy.

Interferon-alpha resistance in renal carcinoma cells is associated with defective induction of signal transducer and activator of transcription 1 which can be restored by a supernatant of phorbol 12-myristate 13-acetate stimulated peripheral blood mononuclear cells

Therapy of selected human malignancies with interferon-alpha is widely accepted but often complicated by the emergence of interferon-alpha resistance. Interferon is a pleiotropic cytokine with antiproliferative, antitumour, antiviral and immunmodulatory effect; it signals through the Jak-STAT signal transduction pathway where signal transducer and activator of transcription 1 plays an important role. Here we report both, a lack of signal transducer and activator of transcription induction in interferon-alpha resistant renal cell carcinoma cells and signal transducer and activator of transcription 1 reinduction of phorbol 12-myristate 13-acetate-stimulated peripheral blood mononuclear cells supernatant. Preliminary experiments on the identification of the molecules that reinducing signal transducers and activators of transcription 1 indicate that interferon-gamma may be the responsible candidate cytokine, but several others may be involved as well. This work provides the basis for therapeutic strategies directed at the molecular modulation of interferon-alpha resistance in human neoplasms.

Screening, confirmation and quantification of diuretics in urine for doping control analysis by high-performance liquid chromatography-atmospheric pressure ionisation tandem mass spectrometry

A sensitive, selective, robust and fast method to identify 32 diuretics and masking agents in urine is described. The analytical procedure is reduced to a single XAD extraction step for sample preparation, followed by reversed-phase liquid chromatography in combination with atmospheric pressure ionisation/tandem mass spectrometry. This technique is, after minor modifications, suitable for screening analyses and confirmation of identity as well as quantitation of diuretics. Considerations relating to the stability and metabolism of the compounds are given if relevant for routine screening analyses.

Risk factors for prolonged ventilation after cardiac surgery using APACHE II, SAPS II, and TISS: comparison of three different models

OBJECTIVE

To identify the risk for prolonged mechanical ventilation in cardiac surgical patients.

DESIGN

Prospective study with retrospective combination of a second database.

PATIENTS

Six hundred and eighty-seven patients after cardiac surgery over a period of 12 months.

MEASUREMENTS

Demographic data were recorded preoperatively, and surgical procedures intraoperatively using a surgical database designed for quality control. Length of ICU and hospital stay, and hospital outcome were recorded. Severity of illness was assessed daily using APACHE II, SAPS II, and Organ Failure Score. Intensity of treatment and nursing care was monitored by means of the Therapeutic Intervention Scoring System (TISS). Univariate and multivariate analyses were performed using logistic regression. The predictive value of the identified variables was tested by the Wilcoxon test using the receiver operating characteristic curve.

MAIN RESULTS

Sixty-two patients (9.0%) were ventilated for > 48 h and accounted for 42.8% of the total costs in the ICU. The pre- and intraoperatively collected data produced a model with weak predictive capacity for prolonged ventilation [area under curve (AUC) 73.22 and 71.08, respectively]. The use of TISS and SAPS postoperatively resulted in an effective model of prediction (AUC 93.76). Adding the occurrence of reoperation, reintubation, emergency transfusion, intraaortic balloon pumping, and need for total parenteral nutrition to the model further improved its predictive capacity (AUC 94.74).

CONCLUSIONS

The present results strongly suggest that data collected postoperatively using established scoring systems as well as documented events of high clinical impact for risk assessment and quality control are reliable predictors of prolonged ventilation.

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.

Tumour microdissemination and survival in metastatic melanoma

The value of tyrosinase messenger RNA (mRNA) detection by reverse-transcriptase polymerase chain reaction (RT-PCR) as a marker for circulating melanoma cells remains controversial. However, it has been suggested that detection of melanoma cell mRNA may be used to evaluate prognosis and disease progression in patients with advanced malignant melanoma. We used a highly sensitive tyrosinase RT-PCR detection assay to test peripheral blood specimens of 80 patients with metastatic malignant melanoma. Moreover, we developed a multiple marker RT-PCR assay detecting a variety of additional melanocyte/tumour specific markers addressing the potential heterogeneity of gene expression of circulating melanoma cells. Thus subgroups of 32 and 12 out of all the 80 patients were also analysed for multimarker gene expression in their peripheral blood and bone marrow specimens, respectively. Altogether, 15 out of 80 patients tested positive for one or more molecular markers with heterogeneous melanocyte/tumour gene expression patterns. All RT-PCR positive patients presented with progressive and widely disseminated disease. We concluded that the detection of melanoma cell mRNA occurs in a stage of massive tumour progression and may predict poor clinical outcome in advanced malignant melanoma patients (p < 0.001). In addition, the multiple marker RT-PCR analysis was more reliable and sensitive than a single molecular marker assay for the detection of melanoma cells.

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.

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.

Analytical strategy for detecting doping agents in hair

Lists of banned classes of doping agents are released by the International Olympic Committee, adopted by other sports authorities and updated regularly, including the substance classes stimulants, narcotics, diuretics, anabolic agents, peptide hormones, beta-blockers etc. There are different classes of restriction: anabolic and masking agents (anabolic steroids, diuretics etc.) are always banned for athletes regardless of their topical activity (training or competition) several substances are permitted with certain restrictions (caffeine below a cut-off value, or inhalation of some beta 2 agonists) beta-blockers are prohibited in competitions of certain sports disciplines the majority of the substances (stimulants, narcotics etc.) is prohibited during competitions, so that they do not have to be analysed in out-of-competition samples. A differentiation between training and competition period is impossible by means of hair analysis due to the uncertainty of (especially short-term) kinetic considerations related to hair growth. Therefore, the analytical identification of doping relevant substances in hair is not always a sufficient criterion for a doping offence and the identification of stimulants, beta-blockers etc. in hair would be entirely irrelevant. The most interesting target substances are certainly the anabolic agents, because their desired action (enhanced muscle strength) lasts longer than the excretion, leading to sophisticated procedures to circumvent positive analytical results in competition control. Besides the analysis of out-of-competition control samples, the long term detection of steroids in hair could provide complementary information. An analytical approach to the identification of exogenous steroids in hair requires consideration of the presence of many other steroids in the hair matrix interfering the analysis at trace levels, and of a limited chemical stability. The analysis of endogenous steroids in hair appears to be even more complicated, because the possibility of many biotransformation reactions from (into) other precursors (metabolites) has to be taken into account. Precursor substances of anabolic steroids (especially esters as application forms) are very promising analytical targets of hair analysis, because they can only be detected after an exogenous intake. The quantitative evaluation of active parent compounds like testosterone (which is actively involved in physiological processes of hair growth) in hair is still controversial. Clinical applications under reproducible conditions can be useful, but the biovariability of these parameters will probably prevent the definition of acceptable cut-off levels as a criterion of abuse.

[Propane abuse. Extreme dose increase due to development of tolerance]

In spite of its serious sequelae, volatile substance abuse (VSA) attracts very little public attention in Germany. Our case report describes an adult male who inhaled propane for recreational purposes. Initially, he achieved short-lived euphoria and hallucinations. He compensated for the developing tolerance by increasing the dosage, finally consuming 5 litres of fluid propane daily. Getting such quantities was facilitated by his occupational access to propane. Since he abused the propane in an apartment house, he also exposed third parties to the danger of explosion. Clinical examination revealed disturbances in orientation, restricted perceptivity and concentration, reduced mnemonic performance, and psychomotor agitation. All these symptoms diminished during a 6-month follow-up. The relationship of his organic mental disorder to the abuse of propane was not clear, since he had also abused alcohol.

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.

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.

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.

Altered expression of beta 1 integrins in renal carcinoma cell lines exposed to vinblastine

BACKGROUND

Cellular expression of P-glycoprotein (P-gp) which mediates a well characterized mechanism of multidrug resistance (MDR) has been reported previously to be associated with an enhanced tumor dissemination. Since adhesion receptors of the beta 1 integrin family play a substantial role in tumor spread, we studied expression of VLA-1 to -6 in a total of four renal carcinoma cell (RCC) lines prior to and after induction of MDR via exposure to vinblastine.

MATERIAL AND METHODS

Surface expression of P-gp and VLA-1 to -6 was determined immunocytochemically in untreated pre-established renal carcinoma cell lines (Caki-1, Caki-2, A498) and a cell line derived from a RCC patient who had received a vinblastine-containing therapy regimen prior to the resection of a local relapse of the tumor (EH). Resistant sublines were cultivated in the presence of 1 ng/ml and 10 ng/ml of vinblastine sulfate, respectively.

RESULTS

In all cell lines examined, an increased number of P-gp expressing cells was observed upon exposure to vinblastine. Significant changes of beta 1 integrin expression were observed in three of four RCC cell lines. A de novo expression of VLA-1, VLA-2, and VLA-4 as detected by immunocytochemistry occurred in resistant Caki-1 cells. A498 cells showed an increasing number of VLA-2 positive cells in drug resistant sublines. In contrast, a decrease of VLA-2 and VLA-5 expression was found in EH cells, the only cell line exhibiting P-gp expression prior to vinblastine exposure. Caki-2 cells showed no significant changes of surface integrin expression upon treatment with vinblastine.

CONCLUSIONS

Our results demonstrate that induction of drug resistance can be associated with substantial changes of the integrin phenotype in renal carcinoma cell lines. In our experiments, among all VLAs studied, VLA-2 was most frequently altered in expression by RCC cell lines. The significance of these observations for aberrant metastatic properties of multidrug resistant tumor cells will be the subject of further studies.

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.

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.

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.

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.

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.

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.