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Biomedical subjects

S Stier

Publications and source records attributed to S Stier.

13 recordsLinked to original sources

A method for the rapid construction of cRNA standard curves in quantitative real-time reverse transcription polymerase chain reaction.

Quantification of nucleic acids, especially of mRNA, is increasingly important in biomedical research. The recently developed quantitative real-time polymerase chain reaction (PCR) - a highly sensitive technology for the rapid, accurate and reproducible quantification of gene expression - offers major advantages over conventional quantitative PCR. Transcript quantification is performed in the exponential phase of the PCR reaction through extrapolation of fluorescence signals from a standard calibration curve which represents the initial copy number for a given fluorescence signal. We have developed a method for gene transcript quantification which is based on a LightCycler - assisted real-time PCR in combination with a simple and rapid approach for the construction of external cRNA standards with identical gene sequences as the target gene. Synthesis of cRNAs was performed by in vitro transcription with T7 RNA polymerase followed by reverse transcription and real-time PCR. We applied this approach for transcript quantification of eukaryotic initiation factor 3 p110 (EIF3S8) mRNA in normal testicular tissue. We also present a rapid and simple strategy for the construction of cRNA standards for use in real-time PCR.

Adult↗

Transforming growth factor beta 1 mediates cell-cycle arrest of primitive hematopoietic cells independent of p21(Cip1/Waf1) or p27(Kip1).

The regulation of stem cell proliferation is a poorly understood process balancing rapid, massive blood cell production in times of stress with maintenance of a multipotent stem cell pool over decades of life. Transforming growth factor beta 1 (TGF-beta 1) has pleiotropic effects on hematopoietic cells, including the inhibition of primitive cell proliferation. It was recently demonstrated that the cyclin-dependent kinase inhibitors, p21(Cip1/Waf1) (p21) and p27(Kip1) (p27), can inhibit the proliferation of hematopoietic stem cells and progenitor cells, respectively. The relation of TGF-beta 1 stimulation to p21 and p27 was examined using a fine-mapping approach to gene expression in individual cells. Abundant TGF-beta 1 expression and p21 expression were documented in quiescent, cytokine-resistant hematopoietic stem cells and in terminally differentiated mature blood cells, but not in proliferating progenitor cell populations. TGF-beta 1 receptor (T beta R II) was expressed ubiquitously without apparent modulation. Cell- cycle-synchronized 32D cells exposed to TGF-beta 1 demonstrated a marked antiproliferative effect of TGF-beta 1, yet neither the level of p21 mRNA nor the protein level of either p21 or p27 was altered. To corroborate these observations in primary cells, bone marrow mononuclear cells derived from mice engineered to be deficient in p21 or p27 were assessed. Progenitor and primitive cell function was inhibited by TGF-beta 1 equivalently in -/- and +/+ littermate controls. These data indicate that TGF-beta 1 exerts its inhibition on cell cycling independent of p21 and p27 in hematopoietic cells. TGF-beta 1 and p21 or p27 participate in independent pathways of stem cell regulation, suggesting that targeting each may provide complementary strategies for enhancing stem or progenitor cell expansion and gene transduction.

Adult↗

Identification of syntenin and other TNF-inducible genes in human umbilical arterial endothelial cells by suppression subtractive hybridization.

Endothelial cells play an important regulatory role in inflammatory responses by upregulating various proinflammatory gene products including cytokines and adhesion molecules. A highly potent mediator of this process is tumor necrosis factor-alpha (TNF). In the present study, the suppression subtractive hybridization (SSH) method was employed to identify rarely transcribed TNF-inducible genes in human umbilical arterial endothelial cells. Following mRNA isolation of non-stimulated and TNF-stimulated cells, cDNAs of both populations were prepared and subtracted by suppression PCR. Sequencing of the enriched cDNAs identified 12 genes differentially expressed including vascular cell adhesion molecule-1, monocyte chemoattractant protein-1, interleukin-8 and IkappaBalpha, an inhibitor of the transcription factor nuclear factor-kappaB. Interestingly, also syntenin, a PDZ motif-containing protein which binds to the cytoplasmic domain of syndecans, was identified by SSH. Time course studies using RT-PCR analysis confirmed that all genes were differentially expressed and rapidly induced by TNF. Our data reveal that SSH is a powerful technique of high sensitivity for the detection of differential gene expression in primary arterial endothelial cells.

Carrier Proteins↗

Stem cell repopulation efficiency but not pool size is governed by p27(kip1).

Sustained blood cell production requires preservation of a quiescent, multipotential stem cell pool that intermittently gives rise to progenitors with robust proliferative potential. The ability of cells to shift from a highly constrained to a vigorously active proliferative state is critical for maintaining stem cells while providing the responsiveness necessary for host defense. The cyclin-dependent kinase inhibitor (CDKI), p21(cip1/waf1) (p21) dominates stem cell kinetics. Here we report that another CDKI, p27(kip1) (p27), does not affect stem cell number, cell cycling, or self-renewal, but markedly alters progenitor proliferation and pool size. Therefore, distinct CDKIs govern the highly divergent stem and progenitor cell populations. When competitively transplanted, p27-deficient stem cells generate progenitors that eventually dominate blood cell production. Modulating p27 expression in a small number of stem cells may translate into effects on the majority of mature cells, thereby providing a strategy for potentiating the impact of transduced cells in stem cell gene therapy.

Animals↗

A trial of L-deprenyl for the treatment of neuroleptic-induced parkinsonism.

This study examined the potential of L-Deprenyl, a selective monoamine oxidase-B (MAO-B) inhibitor, for the treatment of neuroleptic-induced parkinsonism (NIP). Thirty-one consecutive schizophrenic or schizophreniform patients were treated with haloperidol in a flexible dose design. Nineteen of them developed NIP and were administered adjunctive L-Deprenyl 10 mg/d for six weeks in an open fixed-dose design. One patient had to be withdrawn from the study because of exacerbation of the NIP. Severity of NIP was mild to moderate throughout the whole study period in all other cases. Five patients were considered to require biperiden 2-4 mg/d in addition to L-Deprenyl after two weeks of treatment, although they did not differ from the other 13 patients in any of the variables studied. A significant improvement in NIP was found in both groups of patients, with no psychotic exacerbation or a change in the dosage of haloperidol. These findings suggest that selective MAO-B inhibitors may be effective in some patients with mild to moderate NIP.

Adult↗

Hand parameter differences between psychiatric patients and normal controls: a preliminary evaluation.

The basic assumption of this study was that it is possible to identify unusual hand features in the hands of unusual populations, and that a combination of certain unusual hand features can be associated with mental illness. One hundred and seventeen people were studied in two groups: 63 mental patients (40 males, 23 females) hospitalized in the Abarbanel Hospital, Israel, and a control group of 54 people (27 males, 27 females). Twelve hand parameters were studied, and 11 of them were found to be significantly different. Out of them, 7 show the significant result of p < 0.001. The results of this study suggest that the features of the hand may be considered as a part of the phenomenon of minor physical anomalies which are apparently neurodevelopmental markers. It suggests also the desirability of further research in this area.

Adult↗

Angiotensin type-1 (AT1) receptor gene expression in primarily cultured human arterial umbilical endothelial cells.

The aim of this study was to investigate the interaction of angiotensin II (Ang II) and human umbilical arterial endothelial cells (HUAEC). Specific binding of 125I-ANG II to primarily cultured HUAEC showed a K(D) of 1.98 +/- 0.53 x 10(-9) M (n = 5) with a maximum binding site of 2.84 +/- 1.07 x 10(-13) mol/mg protein (n = 5). In later passages (third and fifth subculture), this binding site was no longer detectable. Gene expression analysis revealed a strong expression of the angiotensin type-I receptor (AT1-R) in the primarily cultured HUAEC, with a decrease in additional passages. In primarily cultured HUAEC, Ang II (10(-10)-10(-6) M) induced a concentration-dependent increase in intracellular free calcium ([Ca2+]i) that could be blocked by a preincubation with candesartan (TCV-112) but not by PD123319. These data show the expression of the AT1-R in primary cultures of HUAEC. The Ang II-induced increase in [Ca2+]i seems to be mediated by this receptor.

Angiotensin II↗

Bone health is not affected by luteal phase abnormalities and decreased ovarian progesterone production in female runners.

The primary purpose of this study was to determine whether decreased ovarian progesterone production, associated with short and inadequate luteal phases in exercising women, was associated with decreased bone mineral density (BMD) and altered bone metabolism. Thirty-three eumenorrheic menstruating women participated in this study for 3 months. Subjects were required to collect daily urine samples for three consecutive menstrual cycles and have blood and urine collected weekly. Daily urine samples were analyzed for free LH, estrone conjugates (E1C), and pregnanediol 3-glucuronide (PdG), adjusted for creatinine, whereas weekly blood and urine samples were analyzed for bone markers, estradiol, progesterone, FSH, and LH. Based on the analyses of these samples, subjects were divided into three groups: sedentary ovulatory (SedOvul; n = 9), exercising ovulatory (ExOvul; n = 14), and exercising luteal phase defects (ExLPD; n = 10). The three groups were matched for age (27.6 +/- 1.0 yr), weight (60.6 +/- 1.9 cm), and reproductive maturity (14.5 +/- 1.0 yr), PdG production during the luteal phase was lower (P = 0.004) in the ExLPD women compared to that in the SedOvul group (2.4 +/- 0.4 vs. 5.1 +/- 0.6 ng/mL creatinine, respectively). The ExOvul group also had less (P < 0.01) PdG production during the luteal phase (3.5 +/- 0.3 ng/mL creatinine) compared to the SedOvul group. The total production of PdG, as assessed by area under the curve analysis, was also lower (P < 0.001) in the ExOvul and ExLPD groups compared to that in the SedOvul group. E1C production, however, was not different (P > 0.05) among the groups, except for E1C during the early follicular phase, which was lower (P = 0.043) in the ExLPD group than that in the SedOvul group. BMD and biochemical markers of bone metabolism were unaffected by and not associated with the compromised progesterone environment, but BMD values at the proximal femur (r = 0.354; P = 0.061) and total body (r = 0.359; P = 0.056) were associated with decreased early follicular E1C production. We conclude the following. 1) Luteal phase disturbances occur independent of training volume, and volume of training does not have to be severe to result in menstrual disturbances. 2) As a result of exercise, disturbance in progesterone production is not associated with decreased bone mass. 3) Long follicular phases are associated with reduced estrogen production during the early follicular phase, which are both associated with decreased bone mass. 4) Provided the estradiol status is adequately maintained, BMD is unaffected by decreased progesterone production associated with short and inadequte luteal phases in exercising women.

Adolescent↗

Organic delusional syndrome associated with tamoxifen treatment.

The authors describe two cases of tamoxifen-induced organic delusional syndrome that resulted from administration of 40 mg daily for the adjuvant treatment of breast carcinoma. After discontinuation of the tamoxifen therapy, the psychiatric episode resolved within 2 to 4 weeks. Because tamoxifen might cause delusional syndrome, the authors recommend full psychiatric evaluation in appropriate cases.

Adenocarcinoma↗

Lack of effect of 6 g inositol treatment of post-ECT cognitive function in humans.

Cholinergic agonists have been reported to ameliorate ECT-induced memory impairment. Inositol metabolism is involved in the second messenger system for several muscarinic cholinergic receptors. Inositol 6 g daily was given in a cross-over double-blind manner for 5 days before the 5th or 6th ECT in a series of patients. No effect was found on post-ECT cognitive impairment.

Adult↗