Background Fractional exhaled nitric oxide is elevated in allergen-provoked asthma. The cellular and molecular source of the elevated fractional exhaled nitric oxide is, however, uncertain. Objective To investigate whether fractional exhaled nitric oxide is associated with increased airway epithelial inducible nitric oxide synthase (iNOS) in allergen-provoked asthma. Methods Fractional exhaled nitric oxide was measured in healthy controls (n = 14) and allergic asthmatics (n = 12), before and after bronchial provocation to birch pollen out of season. Bronchoscopy was performed before and 24 hours after allergen provocation. Bronchial biopsies and brush biopsies were processed for nitric oxide synthase activity staining with nicotinamide adenine dinucleotide phosphate diaphorase (NADPH-d), iNOS immunostaining, or gene expression analysis of iNOS by real-time PCR. NADPH-d and iNOS staining were quantified using automated morphometric analysis. Results Fractional exhaled nitric oxide and expression of iNOS mRNA were significantly higher in un-provoked asthmatics, compared to healthy controls. Allergic asthmatics exhibited a significant elevation of fractional exhaled nitric oxide after allergen provocation, as well as an accumulation of airway eosinophils. Moreover, nitric oxide synthase activity and expression of iNOS was significantly increased in the bronchial epithelium of asthmatics following allergen provocation. Fractional exhaled nitric oxide correlated with eosinophils and iNOS expression. Conclusion Higher fractional exhaled nitric oxide concentration among asthmatics is associated with elevated iNOS mRNA in the bronchial epithelium. Furthermore, our data demonstrates for the first time increased expression and activity of iNOS in the bronchial epithelium after allergen provocation, and thus provide a mechanistic explanation for elevated fractional exhaled nitric oxide in allergen-provoked asthma.

In order to study estrogen effects on developing human neurons, we have established primary cultures of neurons and glia from 8-13-week human embryo cortex and spinal cord. The neuronal identity of the cultures was verified using the neuronal synaptic vesicle and neuronal endosomal membrane markers synaptotagmin, synapsin and synaptophysin, and the glial contribution to the mixed glial-neuronal cultures was verified using the glial marker glial fibrillary acidic protein (GFAP). We here report expression of estrogen receptor beta (ERbeta) in these cells using RT-PCR and sequencing, RNAse protection assay, immunohistochemistry and immunoblotting. We found that both neuronal and mixed glial-neuronal cultures expressed ERbeta. Treatment with 17beta-estradiol gave an increased expression of ERbeta in both types of cultures. These results suggest that ERbeta is expressed in fetal brain and thus may mediate effects of estrogen in the developing nervous system. Furthermore, the results suggest that expression of ERbeta in fetal brain may be regulated by estrogen.

Recent studies have indicated that at least three regions (AZF a-c) on the long arm of the Y-chromosome code for factors are involved in spermatogenesis. One of the candidate genes in the AZFb region is RBM1a, coding for a protein with an RNA binding motif. In this study, poly clonal antibodies raised against a 15 amino acid peptide, corresponding to residues 263-304 of the deduced amino acid sequence of RBM1a, has been used to localize the RBM1a protein in the human testis. Immunohistochemistry on normal human testis using this RBM1a antibody, localized the antigen to the nuclei of spermatogonia, primary spermatocytes, and round spermatids but not to the nuclei of elongated spermatids. The antibody also specifically identified the nuclei of Sertoli cells, although the fluorescence was not as strong as in the germ cell nuclei it identified. No specific fluorescence was seen in the nuclei of either peritubular, endothelial or Leydig cells. Western blot of normal human testicular tissue using the anti-RBM1a antibody gave rise to a single specific band of approximately 55 kDa, corresponding to the expected size of RBM1a. In view of its expression in germ cells, and because RBM1a has an RNA binding domain, RBM1a may be involved in RNA processing, such as RNA splicing or RNA export which are events necessary for normal spermatogenesis.

We have recently found that values of the transforming growth factor (TGF)beta1 in human ovarian follicular fluid obtained during ovarian stimulation for IVF were higher in women who subsequently became pregnant following embryo transfer. We therefore postulated that TGFbeta1 may have a beneficial effect on the preimplantation embryo and improve the chances of a successful implantation. We have used reverse transcription-polymerase chain reaction (RT-PCR) and immunohistochemistry to investigate the presence in human oocytes and preimplantation embryos of the essential components of the TGFbeta signalling pathway, TGFbeta receptors type I and II and the substrate proteins Smad 2 and 3. We found that both receptors, as well as Smad 2 and 3, were present in the unfertilized oocyte, whereas only the type I receptor and Smad 2 and 3 were present at the blastocyst stage. At the 4-cell and 8-cell stages neither of the receptors was present, but Smad 2 and 3 were present at both stages. These findings support our hypothesis that the TGFbeta1 in follicular fluid may interact with the oocyte and preimplantation embryo via TGFbeta receptors, and that TGFbeta signalling may be important for the development of the oocyte and the preimplantation embryo.

Recent studies have strongly indicated that at least three regions [azoospermia factor (AZF) a-c] on the long arm of the Y-chromosome code for factors involved in spermatogenesis. In order to reveal the prevalence of microdeletions in these regions in a Swedish population, 192 men consecutively referred to our andrology unit due to infertility and showing oligozoospermia (n=53) or azoospermia (n=139) but no obstruction or hormonal disturbances, were investigated. For this study we used a multiplex polymerase chain reaction (PCR) method including 13 pairs of primers divided into five different primer mixes. It was found that four men, all with azoospermia, had deletions including part of the AZFb region and probably the entire AZFc region. Testis biopsies showed different morphology ranging from absence of germ cells to hypospermatogenisis. Of special interest was one patient that was first investigated 10 years ago due to primary infertility and oligozoospermia. Today he has developed azoospermia. It is concluded that the number of patients with microdeletions on the Y chromosome is rather low (less than 3% in highly selected azoospermic men) in our study compared to a number of other studies in which a 1-55% incidence have been reported. It is possible that ethnic differences, selection criteria and methodological aspects can contribute to the difference between the present and previous studies.

The MAGE genes were initially isolated from different kinds of tumors, and based on their virtually exclusive tumor-specific expression in adult tissues, they have been used as targets for cancer immunotherapy. However, although a large number of MAGE genes have now been identified and extensively studied in tumors of various origin, their functions in normal cells remain unknown. Here we describe the isolation and characterization of a novel murine MAGE homologue, Mage-b4. mRNA expression studies in a wide variety of adult and embryonic tissues revealed that Mage-b4 is specifically expressed in fetal and adult gonads. An antibody specific to Mage-b4 was developed, and using this antibody, we found that the Mage-b4 protein was confined to the cytoplasm of germ cells. Double-labeling experiments using antibodies against the meiosis-specific SCP3 protein and the Mage-b4 protein showed that Mage-b4 is down-regulated as the germ cells enter meiosis in adult testis. In contrast, Mage-b4 was expressed in female germ cells throughout meiosis, and the protein was also found in dormant primary oocytes.

Expression of the oxytocin gene has been demonstrated in many tissues outside the brain, e.g. in the corpus luteum and in cumulus cells surrounding the mature oocyte (1). Later, mRNA for the oxytocin receptor was also shown in human cumulus cells (2). Taken together, these findings would indicate a role for oxytocin in fertilization and embryonic development. Our aim in this study was to examine the presence of mRNA for oxytocin and its receptor in human oocytes and pre-embryos of different developmental stage.

To isolate genes involved in morphogenic aspects of testis development, and which may act in cell signaling pathways downstream of the testis-determining gene Sry, we have developed a modified mRNA differential display method named signal peptide differential display. It was used to target those genes that encode proteins having a signal peptide sequence. By using this method, we isolated a gene named testatin. This gene was found to be related to a group of genes that encodes cysteine protease inhibitors known as cystatins. Cystatins and their target proteases have been associated with tumor formation and metastasis, but also are involved in natural tissue remodeling events such as bone resorption and embryo implantation. We show that testatin expression is restricted to fetal gonads and adult testis. Furthermore, testatin is expressed during testis cord formation in pre-Sertoli cells, believed to be the site of Sry action, at a time immediately after the peak of Sry expression. This finding suggests that testatin might be activated by transcription factors that are known to orchestrate the early testis development pathway. This gene therefore represents one of the putative downstream targets likely to have an essential role in tissue reorganization during early testis development.

In order to improve assisted fertilization in humans it is important to elucidate the mechanisms of control of growth and development in the early pre-embryo. Increasing evidence shows that growth factors are of importance for such control mechanisms. As platelet-derived growth factor (PDGF) has been shown to enhance growth in a number of tissues, it may also be important in human pre-embryo development. PDGF acts as a dimer (AA, BB or AB) through its receptors: αα ββ and αβ. In order to study the role of PDGF and its receptors, we have used reverse transcription-polymerase chain reaction (RT-PCR) to examine the presence of transcripts in human pre-embryos that were surplus from the in-vitro fertilization treatment of infertile couples. Transcripts for PDGF A were present in the oocyte, 8-cell, morula and blastocyst stages but not in the 4-cell stage. Transcripts for PDGF B were not detected at any stage. PDGF receptor (PDGFR)-α transcripts were found in the 4-cell, 8-cell and blastocyst stages but not in the oocyte or morula stages. Transcripts for PDGFR-β were detected from the 8-cell, morula and blastocyst stages but not in the oocyte or 4-cell stages. These results show that mRNA synthesis of both PDGF A and the two receptor subunits α and β takes place from the 8-cell stage onwards, suggesting an autostimulatory pathway as a possible mechanism for growth factors during pre-embryo development.

: In order to improve assisted fertilization in humans it is important to elucidate the mechanisms of control of growth and development in the early pre-embryo. Increasing evidence shows that growth factors are of importance for such control mechanisms. As platelet-derived growth factor (PDGF) has been shown to enhance growth in a number of tissues, it may also be important in human pre-embryo development. PDGF acts as a dimer (AA, BB or AB) through its receptors: alpha alpha, beta beta and alpha beta. In order to study the role of PDGF and its receptors, we have used reverse transcription-polymerase chain reaction (RT-PCR) to examine the presence of transcripts in human pre-embryos that were surplus from the in-vitro fertilization treatment of infertile couples. Transcripts for PDGF A were present in the oocyte, 8-cell, morula and blastocyst stages but not in the 4-cell stage. Transcripts for PDGF B were not detected at any stage. PDGF receptor (PDGFR)-alpha transcripts were found in the 4-cell, 8-cell and blastocyst stages but not in the oocyte or morula stages. Transcripts for PDGFR-beta were detected from the 8-cell, morula and blastocyst stages but not in the oocyte or 4-cell stages. These results show that mRNA synthesis of both PDGF A and the two receptor subunits alpha and beta takes place from the 8-cell stage onwards, suggesting an autostimulatory pathway as a possible mechanism for growth factors during pre-embryo development.