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A Peri

Publications and source records attributed to A Peri.

At least 37 records · Page 2Linked to original sources
PubMed1998

Differential inhibitory effects on human endometrial carcinoma cell growth of luteinizing hormone-releasing hormone analogues.

In addition to its function as a key hormone in the regulation of the pituitary-gonadal axis, luteinizing hormone-releasing hormone (LHRH) probably also affects various extrapituitary tissues. LHRH binding sites and in vitro antiproliferative effects of LHRH analogues have been reported in human endometrial cancer. The effects of the LHRH agonist leuproreline and LHRH antagonist antide were studied on the cell growth, DNA synthesis, and cell cycle distribution of the human endometrial cancer cell lines HEC-1A and HEC-1B by the sulforhodamine B (SRB) method, [3H]thymidine assay incorporation, and propidium iodide DNA staining, respectively. In the presence of 1.0-100 microM leuproreline the proliferation of HEC-1A cells was significantly reduced as early as 3 days after drug exposure, with a minimum growth value of 69.9 +/- 3.6% (mean +/- SE) at the highest concentration tested (100 microM). Similar antiproliferative effects were obtained following a 6-day treatment with the LHRH antagonist antide. Also, inhibitory effects on [3H]thymidine incorporation into the DNA of the HEC-1A cell line were noted after a 6-day exposure to both LHRH analogues, in the above-mentioned concentration range. Cell cycle analysis of HEC-1A cells cultured in the presence of 10 microM leuproreline and antide showed a slight accumulation of cells in the G0/G1 phase, while the proportions of cells in the S and G2/M phases concomitantly decreased. No significant effects on proliferation, DNA synthesis, and cell cycle distribution were observed in HEC-1B cells with either leuproreline or antide (up to 100 and 10 microM, respectively) after a 6-day exposure. Both Northern blot analysis and reverse transcription polymerase chain reaction failed to detect expression of mRNA for the LHRH receptor in both HEC-1A and HEC-1B cell lines. In addition, the LHRH analogues did not affect the intracellular free calcium concentration, indicating that the classic signal transduction for LHRH is absent or impaired in HEC-1A cells. The observed direct inhibitory actions on HEC-1A cells support the concept that the two LHRH analogues may exert biological effects via cellular effectors distinct from the "classic" LHRH receptor. Although the mechanism by which these direct actions are produced is still obscure, these results might help to establish the basis for new approaches to the therapy of endometrial cancer.

Antineoplastic Agents, Hormonal↗
PubMed1998

Cyclic adenosine 3',5'-monophosphate-responsive element modulator gene expression in germ cells of normo- and oligoazoospermic men.

In about one third of infertile men the cause of impaired spermatogenesis is not known. Spermatogenesis appears to be mediated at least in part by the pituitary gonadotropins, which activate the cAMP-dependent signaling pathway. The end point of this pathway is the activation of nuclear transcription factors, such as cAMP-responsive element-binding protein and cAMP-responsive element modulator (CREM). These factors, upon binding to gene sequences identified as cAMP response elements, modulate the expression of germ cell-specific genes that, in turn, promote the completion of spermatogenesis. The expressions of the cAMP-responsive element-binding protein and CREM genes create different isoforms, which can be divided into two groups: activators or repressors of gene regulation. Only CREM repressors are expressed in premeiotic germ cells in mice, whereas a switch to the expression of the CREM activator tau is observed from postmeiotic germ cells onward. Completion of germ cell maturation appears to be dependent on this phenomenon. Recently, mice lacking CREM gene expression have been generated. These animals were infertile and presented a developmental arrest of germ cell maturation at the stage of early spermatid. In this report we demonstrate that CREM gene expression also occurs in human germ cells. In particular, we determined by RT-PCR that a switch from the expression of CREM repressors to CREM activators is present in postmeiotic germ cells in normospermic men. Conversely, in oligoazoospermic patients only the expression of CREM repressors was detected. These data were confirmed by in situ hybridization studies in which transcripts for CREM activators were detected in postmeiotic germ cells in testis specimens showing conserved spermatogenesis, but not in specimens showing maturation arrest at the spermatid stage. Thus, our results indicate that the lack of a switch in the expression of CREM gene isoforms may be related to impaired spermatogenesis in humans.

Cyclic AMP Response Element Modulator↗
PubMed1997

Potential roles of osteopontin and alphaVbeta3 integrin in the development of coronary artery restenosis after angioplasty.

Angioplasty procedures are increasingly used to reestablish blood flow in blocked atherosclerotic coronary arteries. A serious complication of these procedures is reocclusion (restenosis), which occurs in 30-50% of patients. Migration of coronary artery smooth muscle cells (CASMCs) to the site of injury caused by angioplasty and subsequent proliferation are suggested mechanisms of reocclusion. Using both cultured human CASMCs and coronary atherectomy tissues, we studied the roles of osteopontin (OPN) and one of its receptors, alphavbeta3 integrin, in the pathogenesis of coronary restenosis. We also measured the plasma levels of OPN before and after angioplasty and determined the effect of exogenous OPN on CASMC migration, extracellular matrix invasion, and proliferation. We found that cultured CASMCs during log phase of growth and smooth muscle cell layer of the coronary atherosclerotic tissues of patients express both OPN mRNA and protein at a significantly elevated level compared with controls. Interestingly, whereas the baseline plasma OPN levels in control samples were virtually undetectable, those in patient plasma were remarkably high. We also found that interaction of OPN with alphavbeta3 integrin, expressed on CASMCs, causes migration, extracellular matrix invasion, and proliferation. These effects were abolished when OPN or alphavbeta3 integrin gene expression in CASMCs was inhibited by specific antisense S-oligonucleotide treatment or OPN-alphavbeta3 interaction was blocked by treatment of CASMCs with antibodies against OPN or alphavbeta3 integrin. Our results demonstrate that OPN and alphavbeta3 integrin play critical roles in regulating cellular functions deemed essential for restenosis. In addition, these results raise the possibility that transient inhibition of OPN gene expression or blocking of OPN-alphavbeta3 interaction may provide a therapeutic approach to preventing restenosis.

Adolescent↗
PubMed1997

People in high latitudes: the "Big Five" personality characteristics of the circumpolar sojourner.

The personality of the polar sojourner has been of interest to psychologists for a number of years. Using the NEO Five Factor Inventory, this study examined the general personality factors of the polar worker compared to a normative population, and how these factors differ according to the worker's occupational classification and the polar region in which he or she is working. It was found that polar workers scored higher than a normative group on all factors except Neuroticism. Comparisons across occupational groups showed that scientists were lower than military personnel on Extraversion and lower than technical/support staff on Agreeableness and Conscientiousness. The analysis by polar region indicated that Antarctic workers were higher than Arctic personnel on Extraversion, Agreeableness, and Conscientiousness. A group of Italian Antarctic personnel, completing a translated form of the NEO-FFI, scored lower than the rest of the polar groups on all factors. These findings are discussed in light of various features of the polar environment and Gunderson's 3-predictor model of polar adaptability.

Adaptation, Psychological↗
PubMed1997

Gene expression of endothelin-1, endothelin-converting enzyme-1, and endothelin receptors in human epididymis.

We have previously reported the presence of endothelin-1 (ET-1) and its receptors in the human testis. In the present study we extended our investigations to human epididymis. The rationale of our study originated from the fact that sperm appear to be immotile during their transit through the epididymis. Hence, it is conceivable that specific factors, unknown to date, are present in this organ, capable of inducing smooth muscle contractions, thus forcing sperm transport. In this paper it is shown that ET-1 messenger ribonucleic acid and protein are readily detectable in the epithelial compartment of the human epididymis, and that ET-converting enzyme-1, which converts the precursor pro-ET-1 into the active peptide ET-1, is expressed in the epididymis, thus indicating an active processing of the prohormone. In addition, two classes of ET receptors were characterized and located in the muscle cells of the epididymis. These receptors correspond, in terms of affinity constants and capacity, to the ETA and ETB receptors previously characterized. These receptors mediate the contractile activity of the epididymis in vitro, thus suggesting that ET-1 can be responsible of sperm progression through this organ, acting via a paracrine mode of action.

Aged↗
PubMed1997

Identification, characterization, and biological activity of endothelin receptors in human ovary.

We previously reported the expression of endothelin-1 (ET-1) in granulosa cells (GCs) of the human ovary and the presence of ET-1-like immunoreactivity in human follicular fluid obtained from women in an in vitro fertilization program. In follicular fluid, but not in plasma, the levels of ET-1-like immunoreactivity were higher in gonadotropin-stimulated vs. spontaneous cycles, suggesting hormonal regulation of follicular ET-1. To identify and characterize ET receptors in human ovary, we performed autoradiography, radioligand binding, and functional studies. Mathematical analysis of families of self- and cross-competition curves among [125I]ET-1, [125I]ET-3, and selective analogs indicates that human ovary expresses both subtypes of ET receptors, i.e. ETA and ETB receptors. However, the concentration of the ETB site was 100-fold lower than that of the ETA one. By using [125I]ET-1, we demonstrated that the density of binding sites in human ovary is not affected by the hormonal milieu (similar concentrations in normal cycling, postmenopausal, and combined oral contraceptive-treated women). In situ binding studies indicate that the majority of ETA and ETB receptors are expressed in the blood vessels of the ovary. In particular, ETA receptors are abundant in the ovulatory follicles and localized in the theca interna, in close proximity to the granulosa layer. Few GCs of the ovulatory follicle were specifically labeled. Conversely, in the rat ovary, used as a control, ETB receptors were predominantly expressed and localized in GCs. Accordingly, ETB receptors negatively regulated estrogen accumulation in rat GCs. In human granulosa-luteal cells, neither ET-1 (unselective ligand) nor ET-3 or sarafotoxin 6c (ETB ligands) affected estrogen or progesterone secretion. ET-1 was 2.5-fold more potent than noradrenaline in eliciting contraction of ovarian artery, acting through the ETA receptor. Our results indicate that in human ovary, at variance with rat ovary, the endothelin system is primarily involved in the regulation of ovarian blood flow and not steroidogenesis.

Adult↗
PubMed1997

Characterizing an ectopic secreting carcinoid with indium-111-DTPA-D-Phe-pentetreotide.

UNLABELLED: This report describes a technique that increases the specificity of 111In-pentetreotide as evaluated in a patient with ectopic Cushing syndrome. METHODS: Two separate SPECT studies were performed with different pharmacologic protocols, both including treatment with cold octreotide. The imaging protocol provides acquisitions at 4 and 24 hr after injection. The quantitative approach was based on the ROI activity (manually designed) of an area of pathological lung uptake (ROI-T) versus background (ROI-NT). Histological, histochemical and specific mRNA measurements confirmed the presence of an SSR2 receptor carcinoid in the lung. RESULTS: The time course of ROI-T/ROI-NT is a linear increase between 4 and 24 hr. Washout with cold octreotide diminished the ROI-T activity content and the saturation protocol increased ROI-T/ROI-NT, confirming the specific nature of the uptake. CONCLUSION: Displacement and saturation protocols in 111In-pentetreotide imaging demonstrated the specificity of tumor binding.

ACTH Syndrome, Ectopic↗
PubMed1996

Cells in vivo and in vitro from osteopetrotic mice homozygous for c-src disruption show suppression of synthesis of osteopontin, a multifunctional extracellular matrix protein.

Mice carrying homozygous disruption of the c-src proto-oncogene (Src-/-) develop osteopetrosis due to an impaired ability of osteoclasts to adhere to the bone surface and/or to form bone-resorbing ruffled border. It has also been reported that osteopontin (OPN), a secreted phosphoprotein, mediates osteoclast adherence to the bone matrix. We report here that cells from Src-/- mice, both in vitro and in vivo, express OPN mRNA and protein at a significantly reduced level as compared to cells from Src+/- and +/+ animals, suggesting a potential role for the proto-oncogene c-src in the regulation of OPN gene expression. Our data also show that OPN gene expression can be induced by treatment of SR-/- cells with epidermal growth factor (EGF) and 12-O-tetradecanoyl phorbol-13-acetate (TPA). Results obtained from studies using inhibitors of receptor tyrosine kinases (RTKs) and protein kinase C (PKC) suggest that PKC and RTK are positioned in a pathway with PKC as the downstream effector for the EGF-induced OPN gene expression in SRC-/- cells, and that pp60c-src and EGF may regulate OPN gene expression through a common signalling pathway. Furthermore, contrary to published reports, our study shows that EGF-mediated cell signalling does not require functional interaction between the EGF-receptor and pp60c-src.

3T3 Cells↗
PubMed1996

Interferon-alpha downregulates expression of the oxytocin receptor in cultured human myometrial cells.

Previous studies in the endometrium of ruminants showed that type I interferon (IFN) prevents oxytocin receptor (OTR) formation. We studied the effect of IFN-alpha on human myometrial cells in culture expressing a high density of biologically active OTR. We found that IFN-alpha induced a 35-50% decrease in OTR mRNA and protein and that this inhibition was time and dose dependent. Maximal inhibition of OTR mRNA was obtained after 2-3 days, whereas 1-(beta-mercapto-beta, beta-cyclopentamethyl-enepropionic acid,2-O-Me-Tyr,Thr4,Orn8,Tyr9-amide)-[125I]vasotocin ([125I]OTA) binding reached a nadir after 3-4 days, with half-maximal inhibitory concentration (IC50) = 1,100 U/ml. Mathematical analysis of multiple homologous competition curves for [125I]OTA indicated that IFN-alpha treatment (5,000 U/ml x 3 days) reduced just the binding capacity (Bmax) without changing the binding affinity. Accordingly, the same treatment with IFN-alpha did not affect the half-maximally effective concentration (EC50) for the oxytocin-induced increase in intracellular calcium but significantly decreased maximal responsiveness (Emax) of myometrial cells to OT stimulation. In conclusion, our data demonstrate, for the first time, a negative regulation by IFN-alpha of the steady-state expression of OTR mRNA in cultured human myometrial cells obtained from nonpregnant uteri. This inhibition was followed by a parallel decrease in both the Bmax for [125I]OTA and Emax for oxytocin, suggesting a decreased OTR protein availability.

Base Sequence↗
PubMed1996

Quantitation of somatostatin receptor type 2 gene expression in neuroblastoma cell lines and primary tumors using competitive reverse transcription-polymerase chain reaction.

We previously reported the presence of somatostatin (SS-14)-binding sites in a wide panel of human neuroblastoma (NB) tumor cell lines. Given that the adrenal gland and its relative embryonal and adult tumors express an abundance of mRNA for somatostatin receptor type 2 (sst2) mRNA, we studied the quantitative expression of sst2 in 6 NB cell lines and 15 primary tumors using competitive reverse transcription (RT)-PCR. This method uses an insertion mutant of the target gene as a competitor for the RT-PCR reaction, thus allowing exact quantitation of sst2 mRNA abundance. We found expression of specific transcripts for sst2 in all of the NB cell lines and tumors investigated (range, 9 x 10(5)-4 x 10(9) molecules/microg RNA). In NB cells, the expression of sst2 was highly correlated with SS-14-binding sites (R = 0.93). In primary tumors, sst2 was positively related to the expression of the neuroendocrine marker secretogranin II (P < 0.05) and negatively related to N-myc amplification (a poor prognostic factor, P < 0.005) and metastatic dissemination (P < 0.05). In addition, Kaplan-Meier curves indicate that sst2 expression is positively related to survival (P = 0.01). In a patient with stage IVs disease (a spontaneously regressing form), we found the highest sst2 expression (4 x 10(9) molecules/microgram RNA), a value relatively similar to that of normal adrenal. In conclusion, these data indicate that quantitation of sst2, as assessed with competitive RT-PCR, could represent a new prognostic tool in the neuroendocrine tumor NB. Since sst2 recognizes octreotide with high affinity, these findings could also have both diagnostic and therapeutic value.

Adult↗
PubMed1995

Uteroglobin gene expression in the rabbit uterus throughout gestation and in the fetal lung. Relationship between uteroglobin and eicosanoid levels in the developing fetal lung.

Uteroglobin (UG) gene encodes a cytokine-like, multifunctional, antiinflammatory protein, with potent phospholipase A2-inhibitory activity. It has been suggested that during implantation this protein protects the embryos from maternal immunological assault, facilitates the maintenance of quiescence in the uterus throughout pregnancy, prevents the onset of premature labor, and helps maintain an inflammation-free respiratory organ. This latter function of UG is suggested to be accomplished by preventing hydrolysis of surfactant phospholipids by a lung-specific phospholipase A2. Using reverse transcription polymerase chain reaction, in situ hybridization, immunofluorescence, and radioimmunoassay, we studied UG gene expression in the rabbit uterus throughout gestation and in the fetal lung. Here, we report that: (a) contrary to previous reports, UG gene expression in the rabbit uterus occurs throughout gestation with a precipitous decline just before parturition; (b) this gene expression is dramatically increased in the fetal lung with increasing gestational age; and (c) while there is an inverse relationship between the levels of UG, PGE2, and PGF2 alpha, a positive correlation was found in that of UG and leukotriene C4 in the fetal lung. Our results raise the possibility that dysregulation of UG gene expression, at least in part, may contribute to the onset of premature labor and the development of inflammatory lung disease in premature neonates.

Animals↗
PubMed1994

Cystic fibrosis and phosphatidylcholine biosynthesis.

The cystic fibrosis (CF) gene defect may be associated with a defect in membrane recycling. We have investigated the metabolism of the main constituent of plasma membrane, phosphatidylcholine (PC). In this study of platelets and fibroblasts, we show an increased uptake of choline into PC of CF cells as compared with normal cells. No accumulation of PC was seen. Other patients with respiratory disease (not CF) showed normal rates of incorporation of choline into platelet PC. Platelets from heterozygote individuals showed intermediate turnover rates of choline incorporation into PC. The increase in choline incorporation into PC in CF platelets was not due to modified or increased sensitivity to either cAMP or prostaglandin E2. The total amount and the proportions of the major phospholipids in platelets of control and CF individuals were identical. These findings indicate an increased turnover rate of this phospholipid in CF cells rather than an increased net synthesis.

Base Sequence↗
PubMed1994

Nonradiometric ELISA-based quantitation and validation of polymerase chain reaction-amplified DNA, including detection of point mutations, without allele-specific amplification, or ligation.

We describe two simple novel procedures, one direct and the other involving hybridization, for the enzyme-linked immunosorbent assay (ELISA)-based detection, quantitation, and validation of polymerase chain reaction (PCR)-amplified DNA. Both procedures are applicable to any PCR reaction, and do not require specially synthesized or enzyme-tagged oligonucleotides. We obtained accurate quantitation of PCR-amplified human cc10kDa cDNA with a sensitivity of about 0.6 fmoles. This cDNA was also used to detect single-base insertions, deletions, and substitutions specifically. Additionally, we could readily distinguish zinc-finger Y chromosome-specific genomic sequences in mixtures of male and female cells and normal and mutant cystic fibrosis transmembrane conductance regulator (CFTR) gene sequences in crude fibroblast lysates. To our knowledge, this is the first report of point mutation detection in solution by ELISA without allele-specific amplification or ligation. These novel procedures have vast potential for basic and clinical applications, including gene expression studies, rapid screening of genetic diseases, detection of oncogene and anti-oncogene mutations, and identification of pathogens (e.g., HIV-1) in clinical specimens.

Base Sequence↗
PubMed1994

Expression of Clara cell 10-kD gene in the human endometrium and its relationship to ovarian menstrual cycle.

Clara cell 10-kD (cc10-kD) protein has been suggested to be the human counterpart of rabbit uteroglobin (UG). Like UG, this protein is also a potent inhibitor of phospholipase A2 (PLA2) and a substrate of transglutaminase. Although it has been established that UG gene expression in the rabbit endometrium is stimulated by progesterone, the expression of cc10-kD gene in the human endometrium is not clearly understood. The present study was undertaken to determine whether the cc10-kD gene is expressed in the human endometrium and whether its level of expression changes in relation to the ovarian menstrual cycle. Using reverse transcriptase polymerase chain reaction (RT-PCR) and immunofluorescence, we demonstrate that the cc10-kD gene is expressed in different stages of the menstrual cycle and that the highest level of expression is reached during the luteal phase. These results suggest that like rabbit UG, cc10-kD gene expression in the human endometrium may be stimulated by progesterone. Since cc10-kD is a potent inhibitor of PLA2 activity, this protein may play an important physiological role in regulating eicosanoid levels in the human uterus.

Animals↗
PubMed1994

Endothelin in the human uterus during pregnancy.

In this study we report the immunolocalization, binding and biological activity of endothelins in the human uterus. Since, in previous studies in the rabbit, sex steroids greatly affected uterine endothelin-1 (ET-1) immunolocalization and binding, we sought to compare results obtained in a relatively steroid-deprived uterus (postmenopausal women) with those obtained in late pregnancy. Two classes of ET receptors were identified in human pregnant and non-pregnant myometrium. One site (ETB) was a low capacity site (0.3 pM/mg protein) that bound with high affinity (0.1 nM), yet no selectivity, ET-1, ET-2, ET-3, sarafotoxin (SRTX) and vasoactive intestinal contractor (VIC). The second site (ETA) was six fold more concentrated than the former (1.9 pM/mg protein) and was relatively selective for ET-1, ET-2 and VIC but showed lower affinity for ET-3 and SRTX. Studies with human myometrial cells indicated that the ETA receptor mediates an increase in intracellular calcium, while the physiological function of the ETB receptor is still unclear. Homologous competition curves for ET-1 were used in order to study the ET receptor density (ETA+ETB) in individual myometrial samples. We found that the concentration of ET receptors did not change during different stages of labour or in postmenopausal women. We identified cells with intense positivity for ET-1 in human decidua. Similar cells were also present in pregnant myometrium, intimately associated with smooth muscle cells. Conversely, no staining for ET-1 was observed in non-pregnant myometrium. A paracrine role for ET-1 in the human uterus is suggested.

Adult↗