Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

---

Query: EC:2.7.7.49 (reverse transcriptase)
31,746 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have examined whether alterations in the growth hormone/insulin-like growth factor-1 axis play a role in the pathogenesis of psoriasis. Serum, urine, full skin biopsies, and suction blister roofs were obtained from patients with psoriasis and from healthy controls. Serum concentrations of insulin-like growth factor-1 and insulin-like growth factor binding protein-3 were measured by radioimmunoassay. Growth hormone-binding protein was measured by ligand-mediated immunofunctional assay. Growth hormone concentration in urine was measured by an immunometric assay, and growth hormone receptor-gene expression was measured by RNase protection assay or by quantitative reverse transcriptase polymerase chain reaction in total RNA isolated from epidermal suction blister roofs. Serum concentrations of insulin-like growth factor-1 (249 +/- 12 micrograms per liter, mean +/- SEM, n = 42, and 277 +/- 21 micrograms per liter, n = 9, for psoriatic patients and controls, respectively), insulin-like growth factor binding protein-3 (3.1 +/- 0.08 mg per liter, n = 42, and 3.3 +/- 0.22 mg per liter, n = 9), growth hormone-binding protein (344 +/- 65 pmol per liter, n = 10, and 311 +/- 83 pmol per liter, n = 9), urinary growth hormone excretion during 24 h (12.8 +/- 2.7 microIU per 24 h, n = 12, and 12.3 +/- 1.6 microIU per 24 h, n = 9), and epidermal growth hormone receptor gene expression [32 +/- 12 x 10(3) mRNA transcripts per microgram total RNA (involved skin), n = 11, and 47 +/- 14 x 10(3) mRNA transcripts per microgram total RNA, n = 9] were similar in patients and controls. For insulin-like growth factor-1 and insulin-like growth factor binding protein-3 the values in psoriatic patients were also similar to those in larger control groups, n = 195 and n = 400, respectively. In addition, we found no evidence of local expression of growth hormone or prolactin in full skin punch biopsies from psoriatic involved skin by reverse transcriptase polymerase chain reaction. In conclusion, our results suggest that alterations in the growth hormone/ insulin-like growth factor-1 axis do not play a major role in the pathogenesis of psoriasis.
...
PMID:No evidence for involvement of the growth hormone/insulin-like growth factor-1 axis in psoriasis. 934 96

Urocortin is a recently identified neuropeptide of the CRF family in the mammalian brain, but its expression in human tissue has been little studied. In this study, we examined urocortin expression in human anterior pituitary gland and pituitary adenomas by RIA, high performance liquid chromatography, immunohistochemistry, messenger ribonucleic acid (mRNA) in situ hybridization, and reverse transcriptase-PCR. Immunoreactive urocortin concentrations in normal pituitary tissue extract were 103.25 +/- 39.05 ng/g wet wt (mean +/- SEM; n = 4), and their levels were all significantly higher than those in other portions of central nervous system of the same subjects. High performance liquid chromatography analysis of human pituitary extract demonstrated a single peak corresponding to that of the expected chromatographic mobility of synthetic human urocortin-(1-40). Urocortin-immunoreactive cells were detected in the anterior pituitary gland. Neither urocortin-immunoreactive nerve fibers nor cells were detected in the posterior lobe. Immunostaining in serial mirror tissue sections revealed that 76.55 +/- 3.06% of urocortin-immunoreactive cells expressed GH immunoreactivity, whereas 22.25 +/- 3.02% and less than 1% of urocortin-immunoreactive cells expressed PRL and ACTH, respectively. mRNA hybridization signals of urocortin were also detected in urocortin-immunopositive pituitary cells. The reverse transcriptase-PCR analysis demonstrated a 145-bp RNA band corresponding to that of the expected length of urocortin in all cases of normal pituitary glands examined (n = 3). We also immunostained urocortin in 52 cases of human anterior pituitary adenomas, including GH-producing adenomas (n = 14), ACTH-producing adenomas (n = 13), PRL-producing adenomas (n = 11), and nonfunctioning hormonally inactive adenomas (n = 14). No urocortin immunoreactivity was detected in these adenoma cells, except for one case of GH-producing adenoma and one case of nonfunctioning adenoma. We also performed mRNA in situ hybridization in 27 adenomas. No hybridization signals were detected in these adenomas, except in two cases. The results described above indicated that urocortin is synthesized in human anterior pituitary cells and may play an important role in biological features of normal pituitary gland, possibly as an autocrine or a paracrine regulator
...
PMID:Urocortin expression in human pituitary gland and pituitary adenoma. 936 May 50

The binding of gonadotropin-releasing hormone (GnRH) to its receptor in the anterior pituitary gland is the key molecular interaction regulating the reproductive process of mammals. Here, we report the isolation of a cDNA representing this receptor from rat anterior pituitary and the regulation of expression of its mRNA. The rat GnRH receptor cDNA was composed of 2909 nucleotides and encoded a protein containing 327 amino acids having a seven transmembrane topology. Northern blot analysis on RNA from rat pituitary, ovary and testis showed four different transcripts (5.0, 4.5, 2.5 and 1.3 kb) of which the 5.0 kb form was most abundant. The levels of expression of the transcripts were found to be highest in the pituitary followed by the ovary and the testis (about 40% and 5% compared to pituitary, respectively). Using the more sensitive reverse transcriptase/PCR technique, we also detected GnRH receptor mRNA in the adrenal and the hypothalamus. Measurement of pituitary GnRH receptor mRNA levels (the 5.0 kb form) during the estrous cycle showed the lowest levels at estrus (1.0-fold), a 2.2 +/- 0.57 (mean +/- SEM) -fold increase at diestrus I, a 3.5 +/- 0.41-fold increase at diestrus II, a 2.6 +/- 0.34-fold increase on the morning of proestrus, and a 1.9 +/- 0.25-fold on the afternoon of proestrus. Removal of the ovaries led to a 2.7 +/- 0.29-fold increase in GnRH receptor mRNA levels in the pituitary gland; treatment of ovariectomized rats with estrogen resulted in a significant decrease in GnRH receptor mRNA levels. Our studies demonstrate ovarian regulation of GnRH receptor mRNA expression in the anterior pituitary gland.
...
PMID:Rat gonadotropin-releasing hormone (GnRH) receptor: tissue expression and hormonal regulation of its mRNA. 939 47

Cystic fibrosis (CF) is an inherited disorder associated with severe inflammation and repeated bacterial infection and colonization in the lung. Airway epithelium is involved in defence against bacteria, but this system may be defective in CF. Pro-inflammatory cytokines can stimulate the expression of inducible nitric oxide synthase (iNOS), an enzyme generating nitric oxide, which functions as an important mediator in host defence mechanisms. To understand better the poor resistance to infections in the CF lung, the expression of the iNOS gene was investigated in explanted lungs from patients with cystic fibrosis (n = 13), bronchiectasis (n = 3), emphysema (n = 14), and in normal lungs (n = 8). In addition, bronchial epithelial cell lines were examined to study iNOS gene expression in vitro. Strong immunoreactivity for iNOS was seen in inflammatory cells and bronchial epithelium in all the diseased lungs, except for bronchial epithelium in CF. Quantitative analysis showed a significant reduction in the area of epithelium immunostained in CF [CF 6.8 +/- 1.6 (% +/- SEM); emphysema 18.2 +/- 2.8; normal 9.6 +/- 0.8, P < 0.01], regardless of steroid treatment. These results were supported by in situ hybridization of iNOS mRNA, which showed a pattern of gene expression in CF, emphysema, and normal lung which paralleled that of protein immunoreactivity. Stimulation with cytokines (IL-1 beta, TNF-alpha, and IFN-gamma) increased the expression of iNOS mRNA detected by reverse transcriptase-polymerase chain reaction (RT-PCR) in cultures of normal (16HBE14o-), but not CF (CFBE41o-, with delta F508 CFTR mutation) epithelial cells. Expression of iNOS in inflammatory cells suggests that the gene is normal in CF. Absence of iNOS from bronchial epithelium may be due to low expression of the gene resulting from abnormalities in the signalling system that normally causes induction, such as cytokine receptors, second messengers or transcription factors. The resulting deficiency of the nitric oxide defence system may be relevant to the susceptibility of CF patients to pulmonary bacterial colonization.
...
PMID:Lack of inducible nitric oxide synthase in bronchial epithelium: a possible mechanism of susceptibility to infection in cystic fibrosis. 961 86

The vasoconstrictive peptide endothelin-1 (ET-1) is an autocrine/paracrine peptide of putative pathophysiological importance in renal transplant medicine. The aim of the present study was to develop a method for analysis of gene expression of the renal endothelin system in humans. Only small amounts of tissue are available from renal cortical needle biopsies. Thus, in the present study we developed a quantitative assay based on the competitive reverse transcriptase polymerase chain reaction (RT-PCR) technology. We quantified endothelin A (ET(A)) and B (ET(B)) receptor subtype mRNAs and preproET-1 mRNA levels in renal cortex biopsies obtained before nephrectomy of healthy kidney donors. Mean (+/- SEM) mRNA levels of the ET(A) and ET(B) receptor subtypes in 26 living donors were 212 +/- 23 and 368 +/- 56 amol/microg total RNA, respectively. The preproET-1 mRNA level in 19 living donors was 213 +/- 28 amol/microg total RNA. The inter-assay coefficient of variation (CV) for the assay was 10%; the intra-assay CV was 6-13%. The competitive RT-PCR assay described provides an accurate tool for gene expression investigation of the human endothelin system in renal cortical needle biopsies.
...
PMID:Quantification of mRNA levels of endothelin receptor subtypes and preproEndothelin-1 in renal needle biopsies by competitive reverse transcriptase polymerase chain reaction. 974 17

Parathyroid hormone-related protein (PTHrP) is strongly expressed in the epidermis and has been implicated in the regulation of growth and differentiation of keratinocytes. PTHrP has N-terminal sequence homology with parathyroid hormone (PTH) and binds to the type I PTH/PTHrP receptor, but earlier reports suggest that keratinocytes do not possess this cell surface receptor. In order to determine which PTHrP mRNA isoforms are expressed by keratinocytes and whether the type I receptor mRNA is present, we designed specific primers for reverse transcriptase-polymerase chain reaction. The interaction of PTHrP with other promoters of keratinocyte differentiation is unclear. In particular, 1,25(OH)2D3 is also fundamental in calcium homeostasis and induces changes in intracellular calcium. We therefore investigated the effect of 1,25(OH)2D3 on PTHrP mRNA expression and protein production in cultured human keratinocytes. Cells were incubated for 3 days at concentrations of 1.25(OH)2D3 of 10(-10)-10(-6) mol/L. PTHrP in culture supernatant, measured by two site immunoradiometric assay, was 915 +/- 98 PTHrP fmol/mg of cell layer protein in untreated cultures decreasing to 570 +/- 113 with 10(-8) mol/L and 402 +/- 24 with 10(-6) mol/L 1,25(OH)2D3 (mean +/- SEM, P < 0.01, n = 6). Transcripts for all three PTHrP isoforms (139, 141 and 173 amino acids) were detectable in keratinocyte mRNA. Corresponding to the decrease in PTHrP protein we demonstrated a reduction in all three PTHrP mRNA transcripts after 3 days' incubation with 1,25(OH)2D3 over a concentration range 10(-10)-10(-6) mol/L. Repeated studies failed to detect type I PTH/PTHrP receptor mRNA in human keratinocytes, either in control cultures or in the presence of 1,25(OH)2D3. We have shown that keratinocytes produce abundant PTHrP and that this is modulated by 1,25(OH)2D3, suggesting a physiological role. Further studies are required to investigate the relative expression of PTHrP isoforms, their role in keratinocyte signalling and the receptors involved.
...
PMID:Human keratinocytes express transcripts for three isoforms of parathyroid hormone-related protein (PTHrP), but not for the parathyroid hormone/PTHrP receptor: effects of 1,25(OH)2 vitamin D3. 974 54

Megakaryocytic differentiation of progenitor cells was investigated in nine patients with low-risk myelodysplastic syndromes (MDS) (eight refractor anemia [RA] and one RA with ringed sideroblasts [RARS] and five patients with high-risk MDS (two RA with excess of blasts [RAEB] and three RAEB in transformation [RAEB-T]). Bone marrow-derived CD34+ cells were enriched to a purity of 87% +/- 2% (mean +/- SEM) and assayed in short-term suspension cultures in the presence of 10 ng/mL of PEGylated recombinant human megakaryocyte (MK) growth and development factor (PEG-rHuMGDF) and in addition to 50 ng/mL stem cell factor and 10 ng/mL interleukin-3. Cells of the megakaryocytic lineage were identified by flow cytometric analysis of CD42b (GP1b) and mature MKs by morphologic criteria. Transcription of c-mpl receptor-specific mRNA in the CD34+ cells of these patients was investigated by full-length reverse transcriptase polymerase chain reaction of the p form of c-mpl as well as of the alternative splice product c-mpl k. CD34+ cells from seven healthy bone marrow donors served as controls. Differentiation along the MK pathway was stimulated in five patients with RA. C-mpl mRNA was expressed in the CD34+ cells in all cases. In three low-risk patients the capacity for in vitro MK growth was absent or minimal even though mRNA for c-mpl receptor was detected in the CD34+ cells of this group as well. In patients with high-risk MDS, PEG-rHuMGDF stimulated in vitro MK growth from CD34+ cells in only one of five cases. As in the patients with low-risk MDS, c-mpl mRNA for both c-mpl p and c-mpl k splicing products was detected. These results indicate that the in vitro response to stimulation with c-mpl ligand discriminates between two groups of patients with low-risk MDS and that the observed defect in megakaryocytic development is unrelated to the level of c-mpl expression in both low-risk and high-risk MDS.
...
PMID:Characterization of defective megakaryocytic development in patients with myelodysplastic syndromes. 1008

The mechanism by which oestrogen and hormone replacement therapy (HRT) maintain bone mass in women is still unclear. It has previously been shown that cells of osteoblast lineage in vivo, particularly osteocytes, express oestrogen receptor alpha (ERalpha). Nevertheless, it is still debatable whether oestrogen and the ovarian steroids have a direct affect on osteocytes. If they could regulate osteocyte ERalpha expression, this would be strong evidence for the involvement of these cells in the hormonal regulation of bone mass. This study therefore aimed to compare bone biopsies from women who were replete with ovarian steroids (pre-ovariectomy or post-HRT) with those from the same women when hormone-deficient (post-ovariectomy or pre-HRT) for cellular localization of ERalpha protein or mRNA expression by indirect immunofluorescence, or by in situ hybridization combined with reverse transcriptase-polymerase chain reaction (IS-RT-PCR) respectively. Image analysis showed that proportions of osteocytes positive for immunodetectable ERalpha were higher in hormone-replete than in hormone-deficient women (25+/-SEM 3 per cent, 12+/-SEM 4 per cent, respectively; n=5), with similar but non-statistically significant changes in osteoblasts. This was observed even when HRT was commenced 18 years after menopause. In contrast, grain volume/unit cell area of osteoblast mRNA signal was markedly higher when hormone-deficient (0.055+/-0.01) than when hormone-replete (0.016+/-0.004), with similar but non-significant differences in osteocytes. This preliminary study indicates up-regulation of osteocyte ERalpha protein by ovarian steroids in these patients, which is accompanied by decreased osteoblast ERalpha mRNA expression, providing further evidence for the involvement of osteocytes in the regulation of skeletal structure by ovarian steroids.
...
PMID:Effect of ovarian steroid deficiency on oestrogen receptor alpha expression in bone. 1041 99

In this study, we examined the role of Fas-signaling in the apoptotic pathway in myelodysplastic syndromes (MDS). Ficoll-separated mononuclear cells from 18 bone marrow aspirate specimens obtained from 17 MDS patients, 4 normal healthy donors, and 3 acute myeloid leukemia patients transformed from MDS (t-AML) were studied for mRNA expression of Fas-L, Fas, and the effectors of their signaling, Caspase 1 and Caspase 3, using reverse transcriptase polymerase chain reaction. Fas-L, Fas, and Caspase 1 were detectable in all of the samples in the three groups. Caspase 3 was detectable both in MDS and t-AML specimens but was negligible in normal cells. The apoptotic index (AI%) determined by in situ end labeling of fragmented DNA in 4-hour cultures of mononuclear cells was significantly higher in MDS cells compared to normal or t-AML cells (mean +/- SEM: 2.3% +/- 0.4% in MDS, n = 10 vs. 0.6% +/- 0.2%, n = 4, P = 0.014 in normal cells, and 0.2% +/- 0.2%, n = 3, P = 0.007 in t-AML cells). Treatment of MDS cells with anti-Fas-L antibody suppressed apoptosis (AI%: 2.1% +/- 0.6% in untreated vs. 1.37% +/- 0.5% in treated, n = 6, P = 0.02), indicating functional participation of Fas-signaling in MDS. Further, it was found that Fas-L, Fas, and Caspase 1 mRNA expression remained unchanged in 4 hours. Caspase 3 expression appeared in normal cells after 4 hours and was present at both 0 and 4 hours in MDS and t-AML cells. In contrast to persistent expression in normal and t-AML cells, cells from the 5 MDS patients studied consistently showed significantly lowered or undetectable expression of a negative regulator of Fas, called Fas-associated phosphatase-1 (Fap-1) after 4 hours. Thus, the high AI% in MDS corresponds to a rapid decline in Fap-1. Furthermore, in tumor necrosis factor alpha (TNF-alpha) treated HL60 promyelocytic cells, a definite periodicity in the expression of different mRNAs was observed with upregulation of TNF-alpha itself at 30 minutes, increased expression of Fas and the appearance of Fas-L after 2 hours, and a decrease in Fap-1 expression after 8 hours. These results suggest that TNF-alpha not only induces the effectors of Fas-signaling but also may downregulate the inhibitor. We conclude that a spontaneous and rapid down-regulation of Fap-1, possibly induced by TNF-alpha, a cytokine shown to be present in excess in MDS marrows, may underlie the increased apoptotic death of hematopoietic cells in these patients. Interference with Fap-1 turnover may provide a new therapeutic modality for MDS.
...
PMID:Spontaneous down-regulation of Fas-associated phosphatase-1 may contribute to excessive apoptosis in myelodysplastic marrows. 1049 46

Angiogenesis plays a key role in solid tumor growth. The purpose of this work was to study angiogenesis in acute myeloid leukemia (AML). We stained bone marrow samples from 20 adult patients with untreated AML and 20 normal controls using endothelial cell markers (ULEX-E and von Willebrand factor [vWF]). The number of vessels per millimeter length of bone marrow core biopsy specimen was scored by light microscopy. Using ULEX-E staining, AML marrows had (average +/- SEM) 8.3 +/- 3.6 vessels/mm (range, 3.7-19.3), whereas normal marrows had 4.3 +/- 1.8 vessels/mm (range, 1.6-7.9). A similar difference was noted using vWF staining (8.6 +/- 3.0 vessels/mm vs 4. 9 +/- 2.2 vessels/mm in AML vs normal bone marrows, respectively). The differences between the numbers of vessels/mm in AML and normal marrows were highly significant (P <.0001 for both ULEX-E and vWF staining). When analyzed by FAB category, there was no difference in the average number of vessels/mm among the different subgroups of AML. Using reverse transcriptase polymerase chain reaction, we observed that the HL-60 and U937 human AML cell lines and 4 of 4 freshly isolated AML cells from untreated patients expressed mRNA for vascular endothelial growth factor (VEGF). Both cell lines as well as all fresh AML isolates tested expressed VEGF protein. Basic fibroblast growth factor was expressed only in HL-60 cells and in only 3 of 4 fresh AML samples. These observations suggest that angiogenesis may play a role in the pathogenesis of AML. Inhibition of angiogenesis could constitute a novel strategy for the treatment of AML. (Blood. 2000;95:309-313).
...
PMID:Evidence of increased angiogenesis in patients with acute myeloid leukemia. 1118 59


<< Previous 1 2 3 4 5 Next >>

---