Biomedical subjects

M Serio

Publications and source records attributed to M Serio.

At least 37 records · Page 2Linked to original sources

PubMed2001

Endothelin-1 production by prostate cancer cell lines is up-regulated by factors involved in cancer progression and down-regulated by androgens.

BACKGROUND: Recent data demonstrate that endothelin-1 (ET-1) concentration increases in plasma of men with advanced, hormone-refractory prostate adenocarcinoma. In addition, ET-1 is involved in osteblastic remodelling and new bone formation, suggesting a role for this vasoactive peptide in the metastatic progression of prostate cancer to the bone. METHODS: We investigated the regulation of ET-1 expression in androgen-sensitive and insensitive prostate cancer cell lines by androgens and several factors involved in progression of prostate cancer (EGF) and bone remodelling (TGFbeta-1, IL1-alpha and IGF-1). RESULTS: Northern analysis and radio immunoassay demonstrated that all the ET-1 pathways are tuned off in the androgen-sensitive LNCaP cell line when compared to the androgen-insensitive PC-3 and DU145. In PC-3 cells transfected with a full-length androgen receptor expression vector (PC-3-AR), treatment with androgens reduced gene expression and secretion of ET-1 without affecting the gene expression of ET-3. Collectively, these data support a role for androgens in the regulation of ET-1 production by prostate adenocarcinoma cells. In PC-3 and DU145 cells, ET-1 gene expression and secretion were up-regulated by TGFbeta-1, EGF and IL1-alpha, whereas IGF-1 was ineffective. Conversely, none of the treatments affected ECE-1 or ET-3 gene expression. CONCLUSIONS: In conclusion, ET-1 production by prostate adenocarcinoma cells is down-regulated by androgens and up-regulated by factors involved in tumour progression indicating a role for this peptide in the biology of prostate cancer. In view of the role exerted by ET-1 in the process of bone metastasis, our data suggest the use of ET-1 receptor antagonists in the treatment of advanced prostate cancer.

Adenocarcinoma↗

PubMed2001

Freak waves in random oceanic sea states.

Freak waves are very large, rare events in a random ocean wave train. Here we study their generation in a random sea state characterized by the Joint North Sea Wave Project spectrum. We assume, to cubic order in nonlinearity, that the wave dynamics are governed by the nonlinear Schrödinger (NLS) equation. We show from extensive numerical simulations of the NLS equation how freak waves in a random sea state are more likely to occur for large values of the Phillips parameter alpha and the enhancement coefficient gamma. Comparison with linear simulations is also reported.

Journal Article↗

PubMed2001

Type-2 somatostatin receptor mRNA levels in breast and colon cancer determined by a quantitative RT-PCR assay based on dual label fluorogenic probe and the TaqMan technology.

We reported previously that the expression of type 2 somatostatin receptor (sst2) was positively related to patient outcome in the childhood tumor neuroblastoma. To quantitate the expression of mRNA sst2 expression, we used a competitive RT-PCR assay. To improve the practicability of this measurement and its applicability to large groups of patients, we present here an original 'real-time' quantitative RT-PCR method, based on a dual-labeled fluorogenic probe and the TaqMan technology. By this method, we have measured sst2 mRNA expression in 24 breast cancer samples and 26 colon carcinomas as well as on the corresponding non-adjacent non-neoplastic tissue of the same patients. The proposed method has a dynamic range of 4 x 10(4) to 4 x 10(8) molecules of sst2 mRNA. The intra-assay precision of the test, evaluated as signal detection variability, was 2.4%. Accuracy, evaluated by the addition of standard RNA to unknown samples, provided a mean recovery of 98+/-2%. A significant correlation has been observed in a study performed in 24 neuroblastoma samples measured both with the proposed method and with a competitive RT-PCR assay (r=0.913, p<0.001). In our preliminary clinical study, no significant differences were observed in sst2 mRNA levels between normal and tumor specimens in both colorectal (normal tissue 5.1 x 10(7)+/-2.0 x 10(7) molecules/microg total RNA, cancer tissue 9.7 x 10(7)+/-4.2 x 10(7)) and breast tumors (normal tissue 5.5 x 10(8)+/-2.0 x 10(8), cancer tissue 4.4 x 10(8)+/-3,7 x 10(8)).However, in colorectal cancer, sst2 mRNA values of subjects with high circulating carcinoembryonic antigen (CEA) levels (>5 ng/ml) were statistically lower (2.3 x 10(7)+/-6.2 x 10(6) molecules/, microg total RNA; p<0.05) than those of subjects with low CEA concentration (1.4 x 10(8)+/-6.7 x 10(7)). Also, the sst2 mRNA ratio between normal and tumor tissue (N/T ratio) resulted significantly inversely related to CEA levels. In breast cancer, a significant difference was found between the mean N/T ratio of negative (below 10 fmol/mg protein) and positive estrogen receptor tumors (p<0.05). Analogous results were found selecting breast tumors on the basis of the progesterone receptor status (p<0.05). The proposed method is accurate, precise, sensitive and less labor-intensive than the competitive RT-PCR assay. For a correct evaluation of sst2 mRNA expression, it seems very important to measure the sst2 expression both in tumor and in the non-tumoral non-adjacent tumor specimens.

Adult↗

PubMed2001

Signal transduction by the chemokine receptor CXCR3: activation of Ras/ERK, Src, and phosphatidylinositol 3-kinase/Akt controls cell migration and proliferation in human vascular pericytes.

Hepatic stellate cells (HSC) and glomerular mesangial cells (MC) are tissue-specific pericytes involved in tissue repair, a process that is regulated by members of the chemokine family. In this study, we explored the signal transduction pathways activated by the chemokine receptor CXCR3 in vascular pericytes. In HSC, interaction of CXCR3 with its ligands resulted in increased chemotaxis and activation of the Ras/ERK cascade. Activation of CXCR3 also stimulated Src phosphorylation and kinase activity and increased the activity of phosphatidylinositol 3-kinase and its downstream pathway, Akt. The increase in ERK activity was inhibited by genistein and PP1, but not by wortmannin, indicating that Src activation is necessary for the activation of the Ras/ERK pathway by CXCR3. Inhibition of ERK activation resulted in a decreased chemotactic and mitogenic effect of CXCR3 ligands. In MC, which respond to CXCR3 ligands with increased DNA synthesis, CXCR3 activation resulted in a biphasic stimulation of ERK activation, a pattern similar to the one observed in HSC exposed to platelet-derived growth factor, indicating that this type of response is related to the stimulation of cell proliferation. These data characterize CXCR3 signaling in pericytes and clarify the relevance of downstream pathways in the modulation of different biologic responses.

Androstadienes↗

PubMed2001

Somatostatin receptor type 2 gene expression in neuroblastoma, measured by competitive RT-PCR, is related to patient survival and to somatostatin receptor imaging by indium -111-pentetreotide.

BACKGROUND: We previously reported that human neuroblastoma cell lines and primary neuroblastoma tumors expressed a variable amount of mRNA for type 2 somatostatin (sst2) receptor gene. We also found that high level of sst2 expression were positively related to patient survival. PROCEDURE: We studied retrospectively 49 primary neuroblastomas. To detect and measure sst2 mRNA expression we developed a quantitative RT-PCR based on competitive PCR. When possible the number of MYCN copies was also measured with competitive PCR. RESULTS;. We found that the lowest level of sst2 mRNA was detected in advanced stages of neuroblastomas (stage IV) when compared with the other stages (P< 0.005). Patients with high levels of sst2 expression (>7 x 10(7) molecules/microg RNA) had a cumulative survival better than those with low sst2 expression (P < 0.0005). This predictive independent value of sst2 (P= 0.005) is retained after stratification for N-myc amplification. Finally we verified that the ex vivo sst2 gene expression in tumor samples was positively related (P < 0.01) to the in vivo semiquantitative determination of sst2 protein, assessed by 111In-pentetreotide imaging. CONCLUSIONS: Our data indicate that the measurement of sst2 mRNA measurement could represent a relevant tool in the prediction of neuroblastoma outcome, independently from MYCN amplification.

Biomarkers, Tumor↗

PubMed2001

Clinical application of 5alpha-reductase inhibitors.

The inhibitors of 5alpha-reductase isoenzymes (1 and 2) can be schematically divided in three groups according they substrate specificity: a) pure or preferential inhibitor of 5alpha-reductase 1; b) pure or preferential inhibitor of 5alpha-reductase 2; c) dual inhibitors. Despite the fact that several steroidal and non-steroidal inhibitors have been synthesized and experimented in pharmacological models, only finasteride has been extensively used for clinical purposes. The largest application of finasteride in man has been human benign prostative hyperplasia (BPH). In addition, finasteride has been recently used for treatment of male baldness with a 50% of objective response. In women, finasteride has been used in some control trials for treatment of hirsutism with an objective favorable response. In conclusion, finasteride appears be useful for BPH, baldness and hirsutism (with caution) treatment. On the basis of experimental observations on distribution of 1 and 2 isoenzymes in human skin, scalp and prostate, the dual inhibitors should be more indicated for treatment of BPH and baldness. Similarly, the dual inhibitors seem indicated in attempting to prevent prostatic cancer. The pure 5alpha-reductase 1 inhibitors seem the ideal drugs for treatment of acne and hirsutism.

5-alpha Reductase Inhibitors↗

PubMed2001

Effect of C-ring modifications in benzo[c]quinolizin-3-ones, new selective inhibitors of human 5 alpha-reductase 1.

The synthesis and the inhibition potency of octahydro- and decahydrobenzo[c]quinolizin-3-one derivatives 3--7, as new non-steroidal selective inhibitors of human enzyme 5 alpha-reductase type 1, are reported. These compounds differ from the recently reported benzo[c]quinolizin-3-one inhibitors 2 by the presence of a fully or partially saturated C-ring. Compounds 3 and 4, with a double bond in the C-ring, were prepared by sequential rearrangement-annulation of isoxazolines 19 and 20. C-ring saturated compounds 5--7 were prepared by the Lewis acid-promoted Mannich-Michael tandem reaction of Danishefsky diene with the appropriate N-t-Boc iminium ion. Inhibition experiments were carried out on 5 alpha R-1 and 5 alpha R-2 expressed by CHO cells. Among the prepared compounds, octahydrobenzo[c]quinolizin-3-one 3, with a double bond at the position 6a--10a, was a potent and selective inhibitor of human 5 alpha R-1 (IC(50)=58 nM). The introduction of a tert-butylcarboxyamide at the position 8 (compound 4) was deleterious for the inhibition activity. The lack of the double bond in the C-ring reduced strongly the inhibition activity of compounds 5--7. The extended planarity of the most potent benzo[c]quinolizin-3-ones as well as favorable interactions of the C-ring unsaturation with the enzyme active site could account for the inhibition activity of these compounds.

3-Oxo-5-alpha-Steroid 4-Dehydrogenase↗

PubMed2001

Cell cycle-dependent expression of CXC chemokine receptor 3 by endothelial cells mediates angiostatic activity.

Endothelial cell receptors for the angiostatic chemokines IFN-gamma-inducible protein of 10 kDa (IP-10) and monokine induced by IFN-gamma (Mig) have not yet been identified, and the mechanisms responsible for the effects of these chemokines on angiogenesis are still unclear. IP-10 and Mig share a common functional receptor on activated T lymphocytes, named CXC chemokine receptor 3 (CXCR3). Using in situ hybridization and immunohistochemistry, we show that CXCR3 is expressed by a small percentage of microvascular endothelial cells in several human normal and pathological tissues. Primary cultures of human microvascular endothelial cells (HMVECs) likewise express CXCR3, although this expression is limited to the S/G2-M phase of their cell cycle. Both IP-10 and Mig, as well as the IFN-gamma-inducible T-cell alpha chemoattractant (I-TAC), which all share high-affinity binding for CXCR3, block HMVEC proliferation in vitro, an effect that can be inhibited by an anti-CXCR3 antibody. These data provide definitive evidence of CXCR3 expression by HMVEC and open new avenues for therapeutic interventions in all conditions in which an angiostatic effect may be beneficial.

Angiogenesis Inhibitors↗

PubMed2001

Variable expression of the transcription factors cAMP response element-binding protein and inducible cAMP early repressor in the normal adrenal cortex and in adrenocortical adenomas and carcinomas.

The molecular mechanisms leading to adrenocortical tumorigenesis have been only partially elucidated so far. Because the pituitary hormone ACTH, via activation of the cAMP pathway, regulates both cell proliferation/differentiation and steroid synthesis in the adrenal cortex, in this study we focused on the cAMP-dependent transcription factors cAMP responsive element modulator (CREM) and cAMP responsive element binding protein (CREB). We studied CREM and CREB expression by RT-PCR in human normal adrenal cortex (n = 3), adrenocortical adenomas (n = 8), and carcinomas (n = 8). We found transcripts corresponding to the isoforms alpha, beta, gamma, and tau2 of the CREM gene in all of the normal adrenal tissues, in the adenomas, and in seven of eight carcinomas. On the other hand, mRNA for the inducible cAMP early repressor isoforms, which derive from an internal promoter of CREM gene, was detected in the normal adrenal and in seven of eight adenomas, but in only three of eight carcinomas. Similarly, CREB transcripts were readily detectable in all normal adrenals and adenomas, whereas they were not found in four of eight adrenal carcinomas. To further characterize the carcinomas, telomerase activity and the expression of the ACTH receptor gene were determined. Telomerase activity in the carcinomas resulted in levels significantly higher than in the adenomas, whereas the levels of ACTH receptor mRNA were lower in the carcinomas. No correlation was found in the carcinomas between the levels of the ACTH receptor transcript and the loss of expression of CREB/inducible cAMP early repressor, suggesting that this alteration is not secondary to an upstream disregulation at the receptor level. In conclusion, our results suggest that an alteration in cAMP signaling may be associated with malignancies of the adrenal cortex.

Adenoma↗

PubMed2001

Expression of cyclic adenosine 3',5'-monophosphate (cAMP)-responsive element binding protein and inducible-cAMP early repressor genes in growth hormone-secreting pituitary adenomas with or without mutations of the Gsalpha gene.

In about 30-40% of GH-secreting adenomas, gain-of-function mutations of the Gsalpha gene, which convert this gene into an oncogene termed gsp, occur. Gsalpha mutations have been related to pituitary tumorigenesis. We focused on 2 nuclear transcription factors that are final targets of the cAMP-dependent pathway and are positively regulated by cAMP signaling, i.e. the cAMP-responsive element binding protein (CREB) and the inducible cAMP early repressor (ICER), that derives from alternative splicing of cAMP-responsive element modulator gene. We examined 21 GH-secreting adenomas, 8 with (gsp(+)) and 13 without (gsp(-)) a mutated Gsalpha. Analysis of CREB and ICER I/II messenger RNA revealed that the levels of both transcripts were higher in gsp(+) than in gsp(-) tumors (CREB/glyceraldehyde-3-phosphate dehydrogenase (GAPDH) mean optical density +/- SE, 2.34 +/- 0.36 in gsp(+) vs. 0.99 +/- 0.22 in gsp(-), P = 0.003; ICER I/GAPDH, 0.53 +/- 0.15 in gsp(+) vs. 0.14 +/- 0.07 in gsp(-), P = 0.01; ICER II/GAPDH, 1.5 +/- 0.21 in gsp(+) vs. 0.83 +/- 0.13 in gsp(-), P = 0.01), although a few cases in both groups did not display this pattern of expression. Moreover, no positive correlation between the levels of CREB and ICER transcripts was observed, suggesting the possible presence of alterations in the mechanisms by which cAMP signaling directs the expression of CREB and/or ICER genes. Our results indicate a complex pattern of expression of nuclear transcription factors that mediate cAMP action in both gsp(+) and gsp(-) tumors, suggesting that, beside Gsalpha gene mutations, different and partially unknown molecular events may contribute to the pathogenesis of these tumors.

Adenoma↗

PubMed2001

Real-Time quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) for the measurement of prostate-specific antigen mRNA in the peripheral blood of patients with prostate carcinoma using the taqman detection system.

Circulating prostate cells can be detected in peripheral blood of patients with clinically localized or advanced prostate carcinoma. Traditionally, nested reverse transcriptase-polymerase chain reaction (RT-PCR) is used for this as a sensitive, but qualitative only, detection system. We developed a quantitative real-time RT-PCR method for measuring prostate-specific antigen (PSA) mRNA in peripheral blood of prostate cancer patients. A quantitative assay was developed using an external standard reference curve generated with RNA from the human prostate cell line LNCaP. Basal blood samples were collected from 44 patients without evidence of distant metastases and from 30 healthy controls. In 29 patients surgically treated with radical prostatectomy, the measurement of PSA mRNA was performed in blood samples collected before, at the end and 6 days after surgery. In 14 patients treated with radiotherapy, the measurements were repeated at 3-month intervals to evaluate time-related changes during therapy. The measurements were also performed for one year at 3-month intervals in one patient treated with anti-androgen therapy. We found detectable PSA mRNA in 14/44 (32%) basal blood samples. A wide range of values were observed in these patients, ranging from 0.5 to 1724 pg of total LNCaP RNA/ml blood. In patients undergoing radical prostatectomy, circulating PSA mRNA was detectable in eight patients in basal samples, and in seven of them also in blood specimens collected at the end of surgery, showing an increase in only two patients. In blood samples collected 6 days later, PSA mRNA was dramatically reduced in all patients, but still present in seven of them. In four patients, whose basal samples were negative, PSA mRNA was detectable in samples collected at the end of surgery and three of them were negative after 6 days. In patients who did not receive surgical treatment, a rapid decrease in PSA mRNA was demonstrated in five patients treated with radiotherapy and in one patient undergoing androgen deprivation. No detectable PSA mRNA was found in healthy controls. The levels of PSA mRNA in peripheral blood from patients with prostate carcinoma can be easily measured by this sensitive, quantitative and reliable procedure. This assay is a promising tool for the detection and follow-up of these patients.

Adenocarcinoma↗

PubMed2001

Cushing's syndrome due to intermittent ectopic ACTH production showing a temporary remission during a pulmonary infection.

OBJECTIVES: In about 15-20% of patients with ACTH-dependent Cushing's syndrome the source of ACTH is outside the pituitary gland. Pulmonary tumours are the most frequent, yet not unique, source of ectopic ACTH. In some instances the localisation of an ACTH-secreting tumour may be problematic. Occult ectopic ACTH secretion indicates the occurrence of ACTH-dependent hypercortisolism with an unknown origin. Another peculiarity of Cushing's syndrome may reside in the episodic cortisol hypersecretion, which can determine a pattern characterised by hypercortisolism together with periods of remission (cyclic Cushing's syndrome). We describe a very challenging case of Cushing's syndrome due to ectopic ACTH hypersecretion, showing virtually all of the most unusual features of the disease. DESIGN: A 55-year-old woman affected by Cushing's syndrome, presenting with biochemical features of ectopic ACTH secretion, has been followed for 7 years. METHODS: Thorough basal and dynamic hormonal assessment through the past 7 years is reported. In addition, the results of extensive imaging studies are presented. RESULTS: The source of ACTH secretion has not been identified so far, and hypercortisolism has been controlled by octreotide treatment. In addition, the patient showed a cyclic pattern of hypercortisolism with a long-term remission period. A unique feature of this case is represented by the fact that we observed a temporary, yet dramatic, short-lasting remission of ACTH and cortisol hypersecretion during a pulmonary infection, which occurred while the patient was hospitalised for a periodic hormonal assessment. CONCLUSIONS: This case well represents the wide spectrum of clinical variability of Cushing's syndrome. Most interestingly, to our knowledge, this is the first report of a case of Cushing's syndrome showing a remission during an acute infection.

Adrenocorticotropic Hormone↗

PubMed2001

[Somatostatin receptors in non-endocrine tumours].

The study of the antiproliferative action of somatostatin (ss) is important not only to understand the regulation of neuroendocrine tumours that express receptors (sst), but also non-endocrine tumours which express these receptors. We previously demonstrated the presence of sst2 in a wide panel of cell lines from human neuroblastoma. Although hypotheses have been put forward that treatment with ss or its analogs may be beneficial in oncological patients, this does not appear to be the case in neuroblastoma; patients with high sst2 levels (who are therefore sensitive to ss treatment) have per se a relatively positive outcome. Therefore, adjuvant treatment with ss is not necessary. Viceversa, patients with a poor prognosis are essentially characterized by a low expression of sst2 (and therefore are insensitive to a therapy with ss). In these patients adjuvant treatment with ss might be indicated, but would have little chance of success. Although the majority of neuroendocrine tumours expresses sst2, pancreas and prostate cancer express sst1 but not sst2, and are therefore insensitive to octreotide treatment which binds preferentially to sst2. Tumours like colorectal carcinoma and breast cancer also express sst2 in their more favourable forms. However, the concentration of sst2 in colorectal cancer is similar, if not lower than that in the surrounding normal tissue. Therefore, the probability of successful adjuvant therapy with ss is relatively low. In breast cancer, it is possible that sensitivity to estrogens may have a positive influence on the expression of sst2. This might justify clinical trials with ss in breast cancer.

Adenocarcinoma↗

PubMed2000

Uteroglobin reverts the transformed phenotype in the endometrial adenocarcinoma cell line HEC-1A by disrupting the metabolic pathways generating platelet-activating factor.

Uteroglobin, originally named blastokinin, is a protein synthesized and secreted by most epithelia, including the endometrium. Uteroglobin has strong anti-inflammatory properties that appear to be due, at least in part, to its inhibitory effect on the activity of the enzyme phospholipase A(2). In addition, recent experimental evidence indicates that uteroglobin exerts antiproliferative and antimetastatic effects in different cancer cells via a membrane receptor. The human endometrial adenocarcinoma cell line HEC-1A does not express uteroglobin. Thus, we transfected HEC-1A cells with human uteroglobin cDNA. The transfectants showed a markedly reduced proliferative potential as assessed by impaired plating efficiency as well as by reduced growth in soft agar. Cytofluorimetric analysis clearly indicated that in uteroglobin-transfected cells the time for completion of the cell cycle was increased. We previously demonstrated that HEC-1A cells actively synthesize platelet-activating factor, one of the products of phospholipase A(2) activity. In addition, we demonstrated that platelet-activating factor stimulates the proliferation of these cells through an autocrine loop. In uteroglobin transfectants, the activity of phospholipase A(2) and platelet-activating factor acetyl-transferase, which are involved in the synthesis of platelet-activating factor, was significantly reduced compared with wild-type and vector-transfected cells (p < 0.05). Our results indicate that enforced expression of uteroglobin in HEC-1A cells markedly reduced their growth potential and significantly impaired the synthesis of platelet-activating factor, an autocrine growth factor for these cells. These data suggest that one possible mechanism for the recently observed antineoplastic properties of uteroglobin may be the inhibition of the synthesis of platelet-activating factor.

Acetyltransferases↗

PubMed2000

Benzo[c]quinolizin-3-ones: a novel class of potent and selective nonsteroidal inhibitors of human steroid 5alpha-reductase 1.

The synthesis and biological evaluation of a series of novel, selective inhibitors of isoenzyme 1 of human 5alpha-reductase (5alphaR) (EC 1.3.99.5) are reported. The inhibitors are 4aH- (19-29) or 1H-tetrahydrobenzo[c]quinolizin-3-ones (35-47) bearing at positions 1, 4, 5, and 6 a methyl group and at position 8 a hydrogen, methyl group, or chlorine atom. All these compounds were tested toward 5alphaR-1 and 5alphaR-2 expressed in CHO cells (CHO 1827 and CHO 1829, respectively) resulting in selective inhibitors of the type 1 isoenzyme, with inhibitory potencies (IC(50)) ranging from 7.6 to 9100 nM. The inhibitors of the 4aH-series, having a double bond at position 1,2, were generally less active than the corresponding inhibitors of the 1H-series having the double bond at position 4,4a on the A ring. The presence of a methyl group at position 4 (as in compounds 39-40 and 45-47), associated with a substituent at position 8, determined the highest inhibition potency (IC(50) from 7.6 to 20 nM). Compounds 39 and 40, having K(i) values of 5.8+/-1.8 and 2.7+/-0.6 nM, respectively, toward 5alphaR-1 expressed in CHO cells, were also tested toward native 5alphaR-1 in human scalp and 5alphaR-2 in human prostate homogenates, in comparison with finasteride and the known 5alphaR-1-selective inhibitor LY191704, and their mechanism of inhibition was determined. They both inhibited the enzyme through a reversible competitive mechanism and again were selective inhibitors of 5alphaR-1 with IC(50) values of 41 nM. These specific features make these inhibitors suitable candidates for further development as drugs in the treatment of DHT-dependent disorders such as acne and androgenic alopecia in men and hirsutism in women.

5-alpha Reductase Inhibitors↗

PubMed2000

Synthesis of 8-chloro-benzo[c]quinolizin-3-ones as potent and selective inhibitors of human steroid 5alpha-reductase 1.

The synthesis of a series of differently substituted 8-chloro-benzo[c]quinolizin-3-ones, as potent and selective human steroid 5alpha-reductase type 1 inhibitors, has been accomplished by a four-step procedure based on the TiCl4-promoted tandem Mannich-Michael cyclization of 2-silyloxy-1,3-butadienes with N-t-Boc iminium ions from quinolin-2-ones. The presence on the benzo[c]quinolizinone nucleus of a methyl group and a double bond at positions 6 and 4-4a, respectively, as in compound 1d, gave rise to one of the most potent non-steroidal 5alphaR-1 inhibitors reported so far (IC50 = 14 nM).

3-Oxo-5-alpha-Steroid 4-Dehydrogenase↗

PubMed2000

The CREM system in human spermatogenesis.

Spermatogenesis is a multi-step process, regulated by endocrine, paracrine and autocrine signals, through which immature germ cells differentiate into spermatozoa. The cAMP-dependent transcription factor CREM directs in the testis the expression of genes related to the structuring of mature spermatozoa. CREM gene expression originates different isoforms, which in turn can be divided into activators or repressors of gene expression. Whereas only CREM repressors are expressed in pre-meiotic germ cells in mice, a switch to the expression of the CREM activator tau occurs in post-meiotic germ cells. In addition, mice lacking CREM gene are infertile and present an arrest of germ cell maturation at the stage of round spermatid. We have demonstrated that CREM gene is expressed also in human germ cells and that a switch from the expression of repressors to activators is present in normospermic men. In particular, CREM tau mRNA is located in the cytoplasm of round spermatids. Conversely, in patients showing a testicular pattern of round spermatid maturation arrest only CREM repressors are expressed. Other reports have confirmed our data, supporting the hypothesis that CREM plays a role also in human spermatogenesis and that the absence of "the CREM switch" can be associated to spermatogenic arrest.

Animals↗

PubMed2000

Effects of erythromycin on human colonic circular muscle in idiopathic chronic constipation.

BACKGROUND: Erythromycin has been shown to have profound prokinetic effects on the gastrointestinal tract of humans and animals, probably through its action on endogenous motilin receptors. The purpose of this study was to determine both the direct and indirect effects ('off contraction') of erythromycin and motilin on ex vivo circular muscle strips of the distal colon from patients with or without idiopathic chronic constipation (ICC). MATERIALS AND METHODS: Cumulative concentrations of erythromycin (1-20 microM) and motilin (0.05-1 microM) were tested in both control and ICC preparations in order to evaluate the direct drugs effect. A range doses of both erythromycin (0.5-10 microM) and motilin (0.05-0.5 microM) were tested on their ability to affect the off-contraction that follows the typical inhibitory response evoked by low frequencies of Electrical Field Stimulation (EFS) (1-5 Hz, 20 V, 1 msec pulse trains lasting 1 min). RESULTS: The direct effect of both erythromycin and motilin was a slight increase (less than 10% of the maximal ACh-induced contraction) in the basal tension, with no dose-response relationship. The off-contraction, evoked by EFS, was not affected by drugs pretreament in control preparations. Conversely, in ICC preparations both drugs significantly increased the off-contraction (about 30%). CONCLUSIONS: Erythromycin causes mainly an indirect contractile effect in circular muscle strips from ICC patients. This effect may be related to the activation of inhibitory neuronal motilin receptors. This activation might potentiate NANC relaxation, proportionally increasing the circumferential reflex contraction that follows the EFS-induced relaxation.

Adult↗