Biomedical subjects

M Bergmann

Publications and source records attributed to M Bergmann.

At least 55 records · Page 3Linked to original sources

PubMed1999

Reversion of the differentiated phenotype and maturation block in Sertoli cells in pathological human testis.

To study the relationship between abnormal Sertoli cell differentiation and spermatogenic impairment, we examined the expression of Sertoli cell markers normally lost at puberty, cytokeratin 18 (CK18), anti-Müllerian hormone (AMH) and M2A antigen, in three children (aged 1-2 years), 50 adults (aged 19-45 years) with obstructive or non-obstructive azoospermia or oligozoospermia, and six patients (aged 1-18 years) with 5 alpha-reductase deficiency. There was CK18 and/or AMH expression, but never M2A antigen expression, associated with spermatogonial arrest or Sertoli cell-only (SCO) syndrome in infertile men. Loss of M2A antigen suggests the transition of Sertoli cells to an adult phenotype, while CK18 and/or AMH expression may be a manifestation of de-differentiation of Sertoli cells. In 5 alpha-reductase deficiency, there was a sequential loss of CK18, M2A antigen and AMH around puberty, associated with partial spermatogenesis. The persistence of immature Sertoli cells expressing M2A antigen was associated with prepubertal seminiferous cords and SCO syndrome. Therefore, 5 alpha-reductase deficiency may prevent the maturation of Sertoli cells, resulting in impairment of spermatogenesis, and loss of M2A antigen expression coincides with a critical step in the Sertoli cell maturation. High follicle stimulating hormone concentrations due to failure of normal Sertoli cell differentiation indicate a normal development pattern of the hypothalamic-pituitary-gonadal axis.

Adolescent↗

PubMed1999

Expression of relaxin-like factor is down-regulated in human testicular Leydig cell neoplasia.

In addition to their role in steroidogenesis in the male, testicular Leydig cells constitutively express large amounts of the peptide relaxin-like factor (RLF), also known as Ley-IL. The Leydig cell-derived RLF belongs to the insulin-like superfamily, which also includes relaxin, insulin and the insulin-like growth factors, and within the testis is a specific marker of Leydig cells. Little information is available either on the regulation of gene expression or on the function of this Leydig cell-derived peptide. In the present study we have investigated the expression pattern of human RLF in patients with rare Leydig cell hyperplasia and adenoma. The expression of both mRNA and protein appear to be decreased in hyperplastic Leydig cells, whereas in the Leydig cell adenomas studied, large central areas of the adenoma were devoid of RLF mRNA and protein. Only Leydig cells located at the periphery of the adenoma displayed expression of RLF, with full agreement between in-situ hybridization and immunohistochemistry. It thus appears that the expression of the RLF gene and its products are down-regulated in Leydig cell hyperplasia and adenoma, consistent with a concomitant dedifferentiation of these cells.

Adenoma↗

PubMed1999

Attenuation of catecholamine-induced immunosuppression in whole blood from patients with sepsis.

Studies performed on healthy volunteers have revealed that catecholamines down-regulate the lipopolysaccharide (LPS)-induced production of tumor necrosis factor (TNF)alpha, interleukin (IL)-6, and IL-1beta. We extended this observation and show that this effect is based on changes in the mRNA concentration of these cytokines. Catecholamines are increased in severe sepsis due to endogenous production and have to be administered exogenously when the disease has proceeded to the state of prolonged hypotension. We here investigated whether the immunomodulating effect of catecholamines could also be demonstrated in the blood of patients with prolonged severe sepsis and of those in prolonged septic shock. Blood was stimulated ex vivo with LPS in the presence and absence of epinephrine and the cytokine protein concentration was determined. In blood of healthy volunteers, epinephrine reduced the LPS-stimulated synthesis of TNFalpha by 62.5% (P< 0.0001), of IL-6 by 39% (P< 0.0001), and of IL-1beta by 40% (P= 0.015), and increased the LPS-stimulated IL-10 production by 77.8% (P < 0.0001). Correspondingly, in blood of patients with prolonged severe sepsis, TNFalpha was reduced by 67.2% (P < 0.0001) and IL-6 was reduced by 32.9% (P < 0.0001); IL-1beta and IL-10 were not modulated by catecholamines in these patients. In blood samples of patients in prolonged septic shock, epinephrine did not modulate cytokine levels of IL-6 and IL-10, and decreased TNFalpha only by 36.4% (P < 0.0001). Interestingly, epinephrine suppressed the IL-1beta production by 73% (P < 0.0001) in blood of patients in prolonged septic shock, which was twice as much as in blood samples of healthy volunteers. The altered response of septic blood to catecholamines might be due to an altered reactivity of leukocytes in the prolonged disease although an additional role of preexisting catecholamines cannot be completely excluded.

Adrenergic beta-1 Receptor Antagonists↗

PubMed1999

Developmental expression of dynamin in the chick retinotectal system.

Dynamin I, a GTPase involved in the endocytic cycle of synaptic vesicle membranes, is believed to support axonal outgrowth and/or synaptogenesis. To explore the temporal and spatial patterns of dynamin I distribution in neuronal morphogenesis, we compared the developmental expression of dynamin with the expression of presynaptic membrane proteins such as SV2, synaptotagmin, and syntaxin in the chick primary visual pathway. Western blots of retina and tectum revealed a steady increase of synaptotagmin and syntaxin from embryonic Day 7 (E7) to E11, whereas for the same time frame no detectable increase of dynamin was found. Later stages showed increasing amounts of all tested proteins until the first postnatal week. Immunofluorescence revealed that SV2, synaptotagmin, and syntaxin are present in retinal ganglion cell axons from E4 on. In later stages, the staining pattern in the retina and along the visual pathway paralleled the formation and maturation of axons. In contrast, dynamin is not detectable by immunofluorescence in the developing retina and optic tectum before synapse formation. Our data indicate that, in contrast to the early expression of synaptotagmin, SV2, and syntaxin during axonal growth, dynamin is upregulated after synapse formation, suggesting its function predominantly during and after synaptogenesis but not in axonogenesis.(J Histochem Cytochem 47:1297-1306, 1999)

Aging↗

PubMed1999

Gonadal histology with testicular carcinoma in situ in a 15-year-old 46,XY female patient with a premature termination in the steroidogenic acute regulatory protein causing congenital lipoid adrenal hyperplasia.

Mutations in the steroidogenic acute regulatory protein (StAR) gene cause congenital lipoid adrenal hyperplasia, characterized by diminished or absence of adrenal and gonadal steroids, resulting in severe adrenal insufficiency and ambiguous or complete female external genitalia in genetic males. We report on a 15-yr-old 46,XY phenotypic female, referred because of lack of pubertal development. ACTH and gonadotropin concentrations were elevated; and aldosterone, cortisol and its precursors, and sex steroids before and after stimulation were below the lower limit of detection. In the StAR gene, a homozygous nonsense mutation (TGG --> TAG) in exon 7 (W250X) was identified. Histologic examination after gonadectomy showed seminiferous tubules containing immature Sertoli cells and a few single germ cells with positive placental-like alkaline phosphatase immunoreactivity, indicating carcinoma in situ. This is the first report on testicular morphology, at a pubertal age, in a female patient with 46,XY karyotype and a mutation in the StAR gene, in whom gonadal neoplasia had developed.

Adolescent↗

PubMed1999

Serum inhibin B in combination with serum follicle-stimulating hormone (FSH) is a more sensitive marker than serum FSH alone for impaired spermatogenesis in men, but cannot predict the presence of sperm in testicular tissue samples.

The measurement of serum FSH is useful in the diagnostic workup of the infertile male, but fails to predict the presence of sperm in testicular tissue. We investigated whether inhibin B reflects testicular morphology and the presence of sperm more accurately than FSH. Serum inhibin B and gonadotropin levels were determined in 91 infertile men undergoing diagnostic bilateral testicular biopsy. In 52 of the 91 patients multiple samples were taken for testicular sperm extraction (TESE). Inhibin B levels were (mean +/- SEM) 238+/-32 pg/mL in men with normal spermatogenesis (n = 9), 102+/-18 pg/mL in men with spermatogenetic arrest (n = 15), 98+/-16 pg/mL in hypospermatogenesis (n = 23), 41+/-6 pg/mL in focal Sertoli cell-only syndrome (SCO; n = 26), and 27+/-8 pg/mL in complete SCO (n = 18). The percentage of SCO tubuli was more strongly correlated to serum inhibin B (r = -0.58; P<0.01) than to FSH (r = 0.34; P<0.05). Similarly, the percentage of tubules with elongated spermatids was significantly (P<0.05) more strongly correlated to serum inhibin B (r = 0.65; P<0.01) than to FSH (r = -0.4; P<0.01). Thus, inhibin B is slightly more sensitive than FSH as an index of the spermatogenic status. Neither FSH nor inhibin B alone, however, could predict the type of spermatogenetic damage exactly. The combination of FSH and inhibin B had high diagnostic sensitivity (88%) and specificity (83%) for the presence of elongated spermatids in testicular biopsies. Sperm could be retrieved in 34 (65%) of the TESE patients. The combination of inhibin B and FSH measurement showed a sensitivity of 75% and a specificity of 73% when identifying patients in whom sperm could possibly be retrieved by TESE. We conclude that although the measurement of serum inhibin B improves the sensitivity of predictive tests for the presence of sperm in histology or for TESE, this parameter cannot accurately predict TESE outcome.

Adolescent↗

PubMed1998

Repression of cyclooxygenase-2 and prostaglandin E2 release by dexamethasone occurs by transcriptional and post-transcriptional mechanisms involving loss of polyadenylated mRNA.

The two cyclooxygenase (COX) isoforms convert arachidonic acid to precursor prostaglandins (PGs). Up-regulation of COX-2 is responsible for increased PG production in inflammation and is antagonized by corticosteriods such as dexamethasone. In human pulmonary A549 cells, interleukin-1beta (IL-1beta) increases prostaglandin E2 (PGE2) synthesis via dexamethasone-sensitive induction of COX-2. Nuclear run-off assays showed that COX-2 transcription rate was repressed 25-40% by dexamethasone, while PGE2 release, COX activity, and COX-2 protein were totally repressed. At the mRNA level, complete repression of COX-2 was only observed at later (6 h) time points. Preinduced COX-2 mRNA was also potently repressed by dexamethasone, yet suppression of transcription by actinomycin D showed little effect. This dexamethasone-dependent repression involved a reduced COX-2 mRNA half-life, was blocked by actinomycin D or cycloheximide, and was antagonized by the steroid antagonist RU38486. Repression of IL-1beta-induced PGE2 release, COX activity, and COX-2 protein by actinomycin D was only effective within the first hour following IL-1beta treatment, while dexamethasone was effective when added up to 10 h later, suggesting a functional role for post-transcriptional mechanisms of repression. Following dexamethasone treatment, shortening of the average length of COX-2 mRNA poly(A) tails was observed. Finally, ligation of the COX-2 3'-UTR to a heterologous reporter failed to confer dexamethasone sensitivity. In conclusion, these data indicate a major role for post-transcriptional mechanisms in the dexamethasone-dependent repression of COX-2 that require de novo glucocorticoid receptor-dependent transcription and translation. This mechanism involves shortening of the COX-2 poly(A) tail and requires determinants other than just the 3'-UTR for specificity.

Cycloheximide↗

PubMed1998

Effect of dexamethasone on interleukin-1beta-(IL-1beta)-induced nuclear factor-kappaB (NF-kappaB) and kappaB-dependent transcription in epithelial cells.

The production of inflammatory mediators by epithelial cells in inflammatory lung diseases may represent an important target for the anti-inflammatory effects of glucocorticoids. Nuclear factor-kappaB (NF-kappaB) is a major activator of inflammatory genes and has been proposed as a target for inhibition by glucocorticoids. We have used human pulmonary type-II A549 and airway epithelial BEAS-2B cells to investigate the effect of glucocorticoids on NF-kappaB regulation and kappaB-dependent transcription. In A549 cells following interleukin-1beta (IL-1beta) treatment, there was no effect of dexamethasone on the disappearance of I kappaB alpha protein, its subsequent reappearance 90-min later or the rapid induction of I kappaB alpha mRNA and transcription rate. Expression of p65 and p50/p105 proteins were also unaffected by dexamethasone. In addition, the rapid IL-1beta-induction of NF-kappaB DNA binding and p65 nuclear localisation was unaffected by short (1-6 hours) dexamethasone pre-treatments. Similarly, BEAS-2B cells showed no effect of dexamethasone on IL-1beta-induced NF-kappaB (p50/p65). Stable transfection of a kappaB-dependent reporter in A549 cells resulted in an 8-9-fold activation by IL-1beta or phorbol ester, that was repressed 30-40% by dexamethasone. However, in these cells, IL-1beta induction of inducible nitric oxide synthase, granulocyte-macrophage colony stimulating factor and cyclooxygenase-2 mRNA showed 70-90% repression by dexamethsone. We, therefore, conclude that in these epithelial cells, the repressive effects of glucocorticoids are not mediated by up-regulation of I kappaB alpha, decreased p50/p65 gene expression or inhibition of NF-kappaB DNA binding. Furthermore, since the maximal repression of IL-1beta or phorbol-ester-induced kappaB-dependent transcription by dexamethasone was less than 40%, simple inhibition of kappaB-dependent transcription cannot by itself account for the full repressive effects of glucocorticoids observed in these cells.

Cell Line↗

PubMed1998

IkappaBalpha degradation and nuclear factor-kappaB DNA binding are insufficient for interleukin-1beta and tumor necrosis factor-alpha-induced kappaB-dependent transcription. Requirement for an additional activation pathway.

Two closely related IkappaBalpha kinases as well as the upstream kinase, NIK, which integrates interleukin-1beta (IL-1beta)- and tumor necrosis factor (TNF)-alpha-dependent activation of the transcription factor NF-kappaB have recently been described. However, in this emerging pathway the role of previously identified components of cytokine-induced NF-kappaB activation, namely phosphatidylcholine-specific phospholipase C and protein kinase C, remains unclear. We now show that, in A549 human alveolar epithelial cells, the activation of a stably transfected NF-kappaB-dependent reporter gene by TNF-alpha and IL-1beta is completely blocked by the phosphatidylcholine-specific phospholipase C inhibitor D609 and the protein kinase C inhibitor RO31-8220. However, IL-1beta-induced IkappaBalpha degradation as well as NF-kappaB nuclear translocation and DNA binding, as determined by Western blot and electro-mobility shift assay, respectively, are not affected by these inhibitors. A similar effect, although less pronounced, is observed with the p38 mitogen-activated protein kinase inhibitor SB 203580. On the basis of these data we propose the existence of a second signaling pathway induced by IL-1beta and TNF-alpha that is activated in parallel to the cascade leading to IkappaBalpha degradation and is specifically required for NF-kappaB-dependent transcriptional competency.

Cell Line↗

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

Medullomyoblastoma: a histological, immunohistochemical, ultrastructural and molecular genetic study.

Medullomyoblastoma is a rare variant of medulloblastoma containing myoblastic elements. A 9-year-old boy developed a cerebellar syndrome and signs of increased intracranial pressure, the cause of which was a tumor of the cerebellar vermis measuring 7 x 4.5 x 4.5 cm. Morphologically the tumor largely consisted of a medulloblastoma component but displayed glial, myoblastic and ganglionic differentiation on light microscopic, immunohistochemical and ultrastructural examination. The non-enhancing rim of the tumor on magnetic resonance imaging showed extensive ganglionic differentiation. The tumor did not express bcl-2, c-myc, or c-erb-B2 oncoproteins and was negative for the p53 gene product. On molecular genetic studies, the tumor did not show allelic loss on chromosome loci, frequently altered in medulloblastomas, such as 17p, 1q and 9q.

Cerebellar Neoplasms↗

PubMed1998

Localization of fibroblast growth factor 2 (FGF-2) protein and the receptors FGFR 1-4 in normal human seminiferous epithelium.

Fibroblast growth factor 2 (FGF-2), which occurs in various isoforms both species and tissue specifically, regulates cell proliferation and differentiation via a dual receptor system consisting of heparan sulphate proteoglycans and receptor tyrosine kinases (FGFRs). This study demonstrates for the first time the distribution pattern of FGF-2 and the receptors FGFR 1-4 in the normal seminiferous epithelium of adult men. In western blot analyses, the polyclonal antibody, anti-FGF-2, shows two immunoreactive bands at 18 and 24 kDa. On paraffin sections, positive immunoreaction occurs within the cytoplasm of spermatogonia. The distribution pattern of the polyclonal anti-FGFR 1-4 antibodies is as follows: anti-FGFR-1 (one 68-kDa band) stains nuclei and cytoplasm of spermatogonia; anti-FGFR-3 (five bands at 68, 78, 105, 125 and 145 kDa) stains the nuclei of all germ cells except those of elongated spermatids; and anti-FGFR-4 (one 48-kDa band) stains the cytoplasm of primary pachytene spermatocytes. We were unable to demonstrate FGFR-2 immunoreactivity either in western blot analysis or on paraffin sections. This distribution pattern suggests that FGF-2 in spermatogonia is involved in the autocrine and paracrine regulation of the proliferation and differentiation of spermatogonia and spermatocytes via the receptors FGFR-1, FGFR-3 and FGFR-4.

Adult↗

PubMed1998

Preoperative TNM-classification is a better prognostic indicator for recurrence of hepatocellular carcinoma after liver transplantation than albumin mRNA in peripheral blood. Liver Transplant Oncology Group.

BACKGROUND/AIM: Survival after orthotopic liver transplantation for hepatocellular carcinoma is limited by a high rate of tumor recurrence. A polymerase chain reaction assay based on the detection of albumin mRNA expression in peripheral blood for detection of hematogenous micrometastasis of hepatocellular carcinoma has been described, which may help to select candidates for orthotopic liver transplantation. METHODS: The prognostic value of a highly sensitive nested reverse transcription-polymerase chain reaction assay was evaluated in comparison with the TNM-classification of the International Union against Cancer in a population of liver transplant candidates. RESULTS: Eighty patients with liver disease and 42 control patients were evaluated. Six of 21 patients with hepatocellular carcinoma and 11 of 59 patients with other diseases of the liver were positive for albumin reverse transcription-polymerase chain reaction, making this assay an indicator of ongoing liver damage without absolute specificity for hepatocellular carcinoma. Twelve patients with hepatoma were followed after liver transplantation and seven of those patients had a tumor recurrence within 12 months. Six of these patients with recurrence had International Union against Cancer stage IV A tumors preoperatively, while only one of them was positive for albumin reverse transcription-polymerase chain reaction before transplantation. Only one patient with a stage I to III tumor had a recurrence within 12 months. CONCLUSIONS: Detection of albumin mRNA in peripheral blood by reverse transcription-polymerase chain reaction seems to be an unreliable marker for assessing hematogenous spread of hepatocellular carcinoma. With International Union against Cancer stage IV A being a much better predictor of tumor recurrence, the practical value of albumin mRNA reverse transcription-polymerase chain reaction for patient selection in liver transplant candidates seems to be very limited.

Adult↗

PubMed1998

Obesity, body fat distribution and body build: their relation to blood pressure and prevalence of hypertension.

OBJECTIVE: To determine the relation of skeletal body build and obesity to blood pressure and the prevalence of hypertension. DESIGN: Cross-sectional data obtained from the baseline recruitment of the EPIC-Potsdam Study, which is part of the European Prospective Investigation into Cancer and Nutrition (EPIC). SUBJECTS: A total of 10,303 subjects (4387 men, aged 40-65 y and 5916 women, aged 35-65 y) were recruited between January 1995 and July 1996. MEASUREMENTS: Anthropometric measures included body mass index (BMI), waist-hip ratio (WHR) and metrik index (MIX) as a measure of body build that is derived from the relation of chest depth and breadth to body height. Systolic and diastolic blood pressure was obtained using automatic oscillometric devices. Hypertension was defined as blood pressure > or = 160/95 mmHg or current use of antihypertensive medication. Information on lifestyle factors were obtained by personal interview. STATISTICAL ANALYSIS: Logistic regression was used to define the association of categories of BMI, WHR, and MIX and the prevalence of hypertension. Odds ratios (ORs) of being hypertensive were estimated comparing the highest to the lowest quintile, adjusting for age, smoking status, alcohol intake level, educational attainment, physical activity categories, and each of the anthropometric variables. RESULTS: The simultaneously adjusted OR of being hypertensive, comparing the highest vs the lowest category, was for BMI 2.3 (95% confidence interval (CI) = 1.6-3.2) in men and 1.8 (95% CI = 1.4-2.5) in women, for WHR 1.8 (95% CI = 1.4-2.4) in men and 1.5 (95% CI = 1.2-2.0) in women, and for MIX (largest chest size vs lowest chest size relative to body height) 2.0 (95% CI = 1.4-2.8) in men and 2.2 (95% CI = 1.6-3.1) in women. CONCLUSION: In addition to measures of overall obesity (BMI) as well as central obesity (WHR), skeletal body build (MIX) was independently associated with the prevalence of hypertension. The biological mechanism relating MIX to hypertension, however, is still unclear and needs further exploration.

Adipose Tissue↗

PubMed1998

Gene expression of profibrotic mediators in bronchiolitis obliterans syndrome after lung transplantation.

Bronchiolitis obliterans syndrome (BOS) develops in one-third of lung transplant recipients. A fibroproliferative process involving mesenchymal cells is observed histopathologically. In order further to evaluate the pathomechanisms of BOS, the gene expression of platelet-derived growth factor (PDGF)-B and transforming growth factor (TGF)-beta 1 in bronchoalveolar lavage (BAL) cells of six lung transplant recipients and appropriate controls was studied. Equal amounts of total RNA were submitted to semiquantitative reverse transcription/polymerase chain reaction (RT-PCR), amplifying actin, PDGF-B and TGF-beta 1 using established protocols and primer sets. The signal/actin ratio was calculated based on laser densitometry measurements. TGF-beta 1 transcripts were detected in all samples, and a slight increase in BOS patients was observed. PDGF-B mRNA was increased in BAL samples from BOS patients compared to unaffected recipients and controls. Plotting the FEV1 in percent of vital capacity and the PDGF expression in BOS patients revealed an increased PDGF signal preceding lung function deterioration. The data were consistent with the hypothesis based mainly on in vitro findings that PDGF and TGF-beta contribute to the development of BOS.

Adult↗

PubMed1998

Intrapartum labetalol for the treatment of maternal and fetal thyrotoxicosis.

Maternal thyrotoxicosis complicates approximately 0.2% of pregnancies. Simultaneous occurrence of maternal and fetal thyrotoxicosis during labor is rare, and control of maternal tachycardia and hypertension, as well as fetal manifestations of thyrotoxicosis, are cornerstones of management. An 18-year-old nulliparous female at 33 weeks gestational age presented in labor with thyrotoxicosis. Fetal tachycardia was present as well. Labetalol therapy resulted in a decrease in maternal pulse and blood pressure, and resolution of fetal tachycardia. Vaginal delivery occurred. Subsequent evaluation demonstrated neonatal thyrotoxicosis and high maternal titers of thyroid-stimulating immunoglobulin. In conclusion, labetalol was beneficial in the treatment of maternal and fetal thyrotoxicosis during labor.

Adolescent↗

PubMed1998

Abnormal surface expression of sialoglycans on B lymphocyte cell lines from patients with carbohydrate deficient glycoprotein syndrome I A (CDGS I A).

The carbohydrate-deficient glycoprotein syndromes (CDGS) are genetic, multisystemic diseases characterized by deficiencies in the glycosylation of many secretory glycoproteins, lysosomal enzymes, and possibly cell surface glycoproteins resulting in central nervous system abnormalities and frequent early death by infection. Here we examined whether membranous glycoconjugates of lymphocytes are affected by this disorder. For this, we analyzed cell surface-expressed sialoglycans of Epstein Barr virus (EBV)-transformed B cell lines derived from peripheral B lymphocytes of several patients with CDGS I A. These CDG-LCL (lymphoblastoid cell lines) expressed differentiation markers comparable to those of other EBV-transformed B cell lines. No apparent defects in the gross glycosylation process of defined complex glycosylated proteins such as the surface-expressed major histocompatibility complex class I glycoprotein or secreted immunoglobulin (IgM) were identified. However, using a novel flow cytometric enzyme assay to measure cell surface alpha2,6 sialylation on live cells we found that CDG-LCL express less alpha2,6 sialylated glycans in comparison to other EBV-transformed B cell lines. Also, CDG-LCL bound less of the B lymphocyte lectin CD22, specific for alpha2,6 sialylated lactosamines and known to modulate B cell receptor mediated signaling, as demonstrated by using a soluble CD22-immunoglobulin fusion protein in flow cytometry. CDG-LCL showed stronger surface staining with the monoclonal antibody 1B2 which detects a distinct group of surface-expressed lactosaminyl epitopes. After pretreatment with neuraminidase of Newcastle disease virus (NDVN) it became apparent that in CDG-LCL a significantly larger portion of the 1B2 epitopes was sialylated in alpha2,3 linkage as compared to other B cell lines. Intracellular alpha2,6 sialyltransferase activity as well as polymerase chain reaction products specific for four different sialyltransferases did not significantly differ in CDG-LCL as compared to other EBV-B cell lines. Differences in sialylation may be caused by the respective oligosaccharide core structures available for alpha2,6 or alpha2,3 sialylation in CDG-LCL. Therefore, lymphocytes derived from CDGS patients have distinct deviations in their surface-expressed lactosaminoglycan structures which may affect functions as exemplified by reduced interactions of CD22 with its ligands.

B-Lymphocytes↗

PubMed1998

Recombinant human follicle stimulating hormone for treatment of male idiopathic infertility: a randomized, double-blind, placebo-controlled, clinical trial.

To examine the role of recombinant human follicle stimulating hormone (rhFSH) in male idiopathic infertility a randomized, double-blind, placebo-controlled study was performed. Of 211 patients screened, 67 were finally included. After two pre-examinations, patients were randomized and treated for 12 weeks, either with 150 IU rhFSH or with placebo. Examinations (physical examination, scrotal ultrasonography, semen analysis, hormone measurements, and in 31 patients electron microscopy (EM) of spermatozoa were performed 6 and 12 weeks after treatment initiation and 6 and 12 weeks after completion of treatment. Pregnancies were recorded for a further 3 months after the last examination. Of the 67 patients included in the study, 34 treated and 31 placebo patients could be analysed. In the treated group, FSH was elevated compared to baseline values (P < 0.001). At the end of treatment testicular volume in the treated group was increased compared to placebo (P < 0.05) and baseline (P < 0.001). Apart from an increase in sperm motility (P < 0.05) in the placebo group and in sperm DNA condensation (P < 0.001) in the treated group no significant changes were observed in semen parameters. Two spontaneous pregnancies in partners of men in the treated group and none in the placebo group occurred. However, two pregnancies occurred in partners of men in the placebo group induced by intrauterine insemination or intracytoplasmic sperm injection. In conclusion, at the chosen dose and duration, rhFSH did not lead to an improvement of conventional or EM sperm parameters nor to an increase in pregnancy rates. However, the increased testicular volume and sperm DNA condensation give reason for further investigations.

DNA↗