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Biomedical subjects

I Goldstein

Publications and source records attributed to I Goldstein.

At least 19 recordsLinked to original sources
PubMed2006

P53 in blind subterranean mole rats--loss-of-function versus gain-of-function activities on newly cloned Spalax target genes.

A tumor suppressor gene, p53, controls cellular responses to a variety of stress conditions, including DNA damage and hypoxia, leading to growth arrest and/or apoptosis. Recently, we demonstrated that in blind subterranean mole rats, Spalax, a model organism for hypoxia tolerance, the p53 DNA-binding domain contains a specific Arg174Lys amino acid substitution. This substitution reduces the p53 effect on the transcription of apoptosis genes (apaf1, puma, pten and noxa) and enhances it on human cell cycle arrest and p53 stabilization/homeostasis genes (mdm2, pten, p21 and cycG). In the current study, we cloned Spalax apaf1 promoter and mdm2 intronic regions containing consensus p53-responsive elements. We compared the Spalax-responsive elements to those of human, mouse and rat and investigated the transcriptional activity of Spalax and human Arg174Lys-mutated p53 on target genes of both species. Spalax and human-mutated p53 lost induction of apaf1 transcription, and increased induction of mdm2 transcription. We conclude that Spalax evolved hypoxia-adaptive mechanisms, analogous to the alterations acquired by cancer cells during tumor development, with a bias against apoptosis while favoring cell arrest and DNA repair.

Animals↗
PubMed2004

Effects of ovariectomy and steroid hormones on vaginal smooth muscle contractility.

The role of steroid hormones in regulating vaginal smooth muscle contractility was investigated. Rabbits were kept intact or ovariectomized. After 2 weeks, animals were continuously infused with vehicle or supraphysiological levels of testosterone (100 microg/day), or estradiol (200 microg/day), for an additional 2 weeks. The distal vaginal tissue was used to assess contractility in organ baths and changes in tissue structure were assessed by histology. Ovariectomized animals infused with vehicle exhibited significant atrophy of the muscularis and decreased epithelial height, resulting in thinning of the vaginal wall. Estradiol infusion increased epithelial height, comparable to that of intact animals, but only partially restored the muscularis layer. In contrast, testosterone infusion completely restored the muscularis layer, but only partially restored the epithelial height. In vaginal tissue strips contracted with norepinephrine and treated with bretylium, electrical field stimulation (EFS) caused frequency-dependent relaxation that was slightly attenuated with vehicle, significantly inhibited with estradiol and significantly enhanced with testosterone. VIP-induced relaxation was slightly attenuated in tissues from vehicle and estradiol-infused groups, but was enhanced in tissues from testosterone-infused animals. Contraction elicited by EFS or exogenous norepinephrine was not significantly altered with ovariectomy or steroid hormone infusion when data were normalized to potassium contraction. However, the tissue from testosterone-infused animals developed significantly greater contractile force to norepinephrine. These observations suggest that steroid hormones may be important regulators of vaginal tissue structure and contractility.

Androgens↗
PubMed2004

Serum androgen levels in healthy premenopausal women with and without sexual dysfunction: Part B: Reduced serum androgen levels in healthy premenopausal women with complaints of sexual dysfunction.

Androgen insufficiency has been associated with decreased libido and arousal in postmenopausal women, but rarely has been evaluated in healthy premenopausal women. In all, 32 healthy premenopausal women were enrolled in this study, 18 with one or more complaints of sexual dysfunction and 14 without. Assays of ovarian and adrenal androgens were measured before and after ACTH stimulation. The women with complaints of sexual dysfunction had significantly lower adrenal androgens than did the control women. There were no differences in the basal ovarian androgens or cortisol levels. After ACTH, both groups stimulated cortisol as well as adrenal and ovarian androgens. In conclusion, premenopausal women with complaints of sexual dysfunction had lower adrenal androgen precursors and testosterone than age-matched control women without such complaints. Further study is required to determine how lower adrenal androgens contribute to female sexual dysfunction.

Adrenal Glands↗
PubMed2004

Serum androgen levels in healthy premenopausal women with and without sexual dysfunction: Part A. Serum androgen levels in women aged 20-49 years with no complaints of sexual dysfunction.

Androgen insufficiency is a recognized cause of sexual dysfunction in men and women. Age-related decrements in adrenal and gonadal androgen levels also occur naturally in both sexes. At present, it is unclear if a woman's low serum androgen level is a reflection of the expected normal age-related decline or indicative of an underlying androgen-deficient state. We studied premenopausal women with no complaints of sexual dysfunction to help define a normal female androgen profile. In all, 60 healthy, normally menstruating women, ages 20-49 y, were studied. The Abbreviated Sexual Function Questionnaire was administered along with a detailed interview. Radioimmunoassay measurements of morning serum testosterone (T), free testosterone (fT), dehydroepiandrosterone-sulfate (DHEAS), sex hormone-binding globulin (SHBG), and free androgen index (FAI) were measured during days 8-15 of the menstrual cycle. In women 20-49 y old without complaints of sexual dysfunction, serum androgen levels exhibit a progressive stepwise decline. Comparing values obtained in women age 20-29 y to those obtained in women 40-49 y, specific hormone decrements were DHEAS 195.6-140.4 microg/dl, serum T 51.5-33.7 ng/dl, fT 1.51-1.03 pg/ml. SHBG did not change significantly in women in this age group. The FAI reflected the age-related decrease in female androgen levels. The framework for the development of a female androgen profile in women with no complaints of sexual dysfunction has been established, and an age-related decrease in testosterone and its adrenal precursor, DHEAS, has been demonstrated. The FAI mirrors these decreases and its usefulness in clinical practice is confirmed. A precipitous decline in all androgens occurs after the decade of the 20s, yet SHBG does not show a significant change throughout the premenopausal years.

Adult↗
PubMed2004

The 'effectiveness' scale--therapeutic outcome of pharmacologic therapies for ED: an international consensus panel report.

Despite availability of outcome measures and scales for assessing erectile dysfunction (ED) treatment efficacy, guidelines are not available for assessing broader therapeutic outcomes or defining treatment failure in ED. An International Consensus Advisory Panel was convened to develop guidelines, definitions and a new algorithm for evaluating treatment effectiveness in ED. These new guidelines are recommended for use in both research and clinical practice. A multidisciplinary, international panel, consisting of 11 senior researchers and clinicians, was convened to address pertinent issues concerning therapeutic outcome assessment for ED. The panel utilized a modified Delphi method of consensus development and proposed a new model for outcomes assessment. This model is inherently testable, using existing instruments and current methods of assessment. Following a comprehensive literature review and discussion, the Panel recommended adoption of a new treatment effectiveness conceptual framework or theoretical model for assessing therapeutic outcomes in ED. Treatment effectiveness is presumed to be a combined function of two other factors, treatment response and treatment satisfaction. Treatment response is based on the combined assessment of efficacy and tolerability, and treatment satisfaction on the combined assessment of patient and partner satisfaction. Taken together, these two domains define an overall domain of treatment effectiveness. This therapeutic index would be derived by independently assessing treatment efficacy and satisfaction by means of event logs, questionnaires or the more typical patient interview methods. In conclusion, the Ad Hoc Advisory Consensus Panel recommends adoption of a new framework or conceptual model for conducting ED outcome trials or clinical research. The concept of 'treatment effectiveness' is proposed as a new 'umbrella concept' or distal outcome to be evaluated.

Consensus Statements as Topic↗
PubMed2003

Congenital limb deficiencies in newborn infants: prevalence, characteristics and prenatal diagnosis.

Congenital limb deficiency (CLD) occurs in 0.54 to 0.59/1000 live-born infants and varies according to its anatomic location, type and cause. Our aim was to present a fetus with a prenatal ultrasonographic diagnosis of CLD (transverse reduction deficiency of the left upper limb), and to determine the prevalence and clinical characteristics of CLD at a tertiary medical centre in Israel. Among 78 500 live-born infants, there were 24 cases of CLD (0.31/1000): 45.8% of the CLD cases with affected upper limbs, 45.8% with affected lower limbs, and 8.4% with both limbs affected; 88.4% of the limb deficiencies were longitudinal and 11.6% were transverse; and, 33.3% (8/24) of the affected newborn infants had additional congenital anomalies. We conclude that CLD is not an infrequent finding in live-born infants. Comprehensive ultrasonography of the fetus allows early prenatal diagnosis of CLD and provides the parents with important information and helps them in their decision regarding the fate of the pregnancy.

Adult↗
PubMed2003

Lower extremity above-knee prosthesis-associated erectile dysfunction.

Blunt pelvic and perineal trauma has been previously reported to result in site-specific veno-occlusive dysfunction and/or site-specific cavernosal artery insufficiency. We herein describe a case of erectile dysfunction in a young previously potent amputee. We postulate that the erectile dysfunction is associated with a newly described form of blunt trauma, that is, site-specific compression from a perineal weight-bearing lower extremity above-knee prosthetic device. It is hypothesized that when the force exerted by the above-knee prosthesis is directed medially towards the ischiopubic ramus, the penile crura and common penile arterial blood supply become susceptible to crush-like injury, since they are in fixed anatomic locations in the perineum sandwiched between the compressive force and the bone. Clinical evaluation of the erectile dysfunction in this patient revealed site-specific corporal veno-occlusive dysfunction and site-specific common penile arterial occlusive pathology in the precise region of the contact of the above-knee prosthesis with the perineum. Further research is needed in above-knee prosthesis design to prevent erectile dysfunction.

Adult↗
PubMed2003

Role of the nitric oxide-cyclic GMP pathway in regulation of vaginal blood flow.

The regulatory role of nitric oxide (NO) in vaginal perfusion remains unclear. We used specific inhibitors of enzymes in the NO-cyclic GMP (NO-cGMP) pathway and investigated their effects on vaginal blood flow in the rabbit. NO synthase (NOS) activity was similar in both the proximal and distal rabbit vagina; whereas, arginase activity was 3.4-fold higher in the distal vagina. Intravenous administration of the NOS inhibitor L-NAME resulted in a 66% reduction in genital tissue oxyhemoglobin and a 53% reduction in vaginal blood flow. This attenuation occurred despite a 20-30% increase in systemic arterial pressure. The arginase inhibitor ABH caused a 2.1-fold increase in genital tissue oxyhemoglobin and 34% increase in vaginal blood flow. The guanylate cyclase inhibitor 1H-[1,2,4]oxadiazolo[4,3,-a]quinoxalin-1-one and the phosphodiesterase type 5 inhibitor sildenafil caused in a 37% reduction and a 44% increase in vaginal blood flow, respectively. These observations suggest that the NO-cGMP pathway is an important regulator of vaginal hemodynamics.

Animals↗
PubMed2003

Functional prostaglandin E (EP) receptors in human penile corpus cavernosum.

In this study, we have characterized functional EP receptors in human corpus cavernosum (HCC) tissue and in HCC smooth muscle cells (SMC). Using RNase protection assays, we determined expression of EP2, EP3I and EP3II receptor mRNA. In organ bath preparations of HCC tissue strips, PGE1 caused dose-dependent relaxation at concentrations below 300 nM. At concentrations greater than 300 nM, PGE1 caused contraction. Addition of the EP1/EP2/EP3 receptor antagonist AH6809 inhibited this contraction and facilitated further relaxation through concentrations above 1 microM of PGE1. The EP1/EP3 receptor selective agonist 17-phenyltrinor-PGE2 caused dose-dependent contraction that was partially attenuated by SC51322, an EP1 selective antagonist. In cultures of HCC SMC, PGE1 stimulated cAMP accumulation in a dose-dependent manner. Interestingly, AH6809 significantly attenuated PGE1-induced cAMP accumulation. Sulprostone, a selective EP3 receptor agonist, induced weak contractions in HCC tissue strips but augmented forskolin-induced cAMP synthesis in HCC SMC. The data in this study suggest that HCC and cultured smooth muscle cells express EP1, EP2 and EP3 receptors. These receptors mediate their responses via different biochemical pathways and are expected to have different responses in regulating smooth muscle tone. Thus, we suggest that the ultimate response in erectile tissue to various prostanoids is the integration of responses elicited by individual EP receptor subtypes to a given ligand.

Aged↗
PubMed2003

Sex steroid hormones differentially regulate nitric oxide synthase and arginase activities in the proximal and distal rabbit vagina.

Nitric oxide synthase (NOS) and arginase have been shown to regulate nitric oxide (NO) production reciprocally in genital tissues. In animal models, NO is an important regulator of vaginal blood flow and vaginal wall contractility. In this study, we investigated the modulation of NOS and arginase activities by estrogens and androgens in the proximal and distal rabbit vagina. In intact control animals, total NOS activity was higher in the proximal (528+/-78 pmol/mg protein) than the distal (391+/-44 pmol/mg protein) vagina. However, arginase activity was higher in the distal (206+/-8 nmol/mg protein) than the proximal (64+/-5 nmol/mg protein) vagina. Ovariectomy enhanced NOS activity in the proximal but not distal vagina with concomitant decrease in arginase activity in both the proximal and distal vagina. In ovariectomized rabbits, replacement with 5alpha-dihydrotestosterone (DHT) or Delta5-androstenediol (Adiol) increased NOS activity beyond that observed in ovariectomized rabbits receiving vehicle. In contrast, DHT and Adiol treatment reduced arginase activity more than that of the ovariectomized rabbits receiving vehicle. Testosterone exhibited inconsistent effects on NOS and arginase activity in the distal and proximal vagina. Estradiol replacement in ovariectomized animals reduced NOS activity in the proximal vagina down to levels that were comparable to intact control animals. However, estradiol positively modulated arginase activity in the distal vagina. Western blot analyses indicated that in the proximal vagina, neural NOS protein levels paralleled the changes observed in enzyme activity. These observations suggest that steroid hormones differentially regulate NOS and arginase activities of the proximal and distal regions of the vagina. Although estrogen treatment reduced total NOS activity in proximal vagina, estrogens are known to enhance vaginal blood flow. This paradoxical observation may be explained by differential regulation of n-NOS and e-NOS in the proximal and distal vagina. We suggest that changes in vaginal blood flow and compliance may depend on the endocrine status and the levels of circulating androgens and estrogens.

Anabolic Agents↗
PubMed2003

Duplex Doppler ultrasound assessment of clitoral hemodynamics after topical administration of alprostadil in women with arousal and orgasmic disorders.

There are limited hemodynamic data in women with arousal or orgasmic disorders and even fewer normative control hemodynamic data in women without sexual dysfunction. In addition, there is limited experience with topical vasoactive agents (used to maximize genital smooth muscle relaxation) applied to the external genitalia during hemodynamic evaluations. The aim of this study was to report duplex Doppler ultrasound clitoral cavernosal arterial changes before and after topical PGE-1 (Alprostadil) administration in control women and in patients with arousal and orgasmic sexual disorders. We found that women with sexual arousal and orgasmic disorders had significantly (p < 0.05) diminished clitoral peak systolic and end diastolic velocity responses compared to controls. Further research is needed to establish the diagnostic role of topical vasoactive agents in the hemodynamic evaluation of women with sexual dysfunction.

Administration, Topical↗
PubMed2002

Long-term safety and efficacy of oral phentolamine mesylate (Vasomax) in men with mild to moderate erectile dysfunction.

The objectives of this study were to evaluate long-term safety and efficacy of phentolamine mesylate, an orally active, rapid-acting alpha-adrenergic receptor antagonist, for the treatment of men suffering from erectile dysfunction (ED). It was an open-label study involving more than 2000 patients. Men received phentolamine mesylate 40 mg or 80 mg (10 tablets/month) as needed for up to 13 months and self-assessed erectile performance using two validated questionnaires. Treatment with phentolamine mesylate was associated with increases in Erectile Function Domain score of the IIEF, successful vaginal penetrations, and in overall satisfaction. Most adverse events were mild or moderate in severity and consistent with the known pharmacodynamic properties of phentolamine. In conclusion, phentolamine mesylate is safe and effective in the long-term treatment of men with mild to moderate ED.

Administration, Oral↗
PubMed2002

Expression of functional prostaglandin D (DP) receptors in human corpus cavernosum smooth muscle.

Prostaglandin D(2) (PGD(2)) binds to specific G-protein coupled receptors (DP) and induces smooth muscle relaxation by stimulating the synthesis of intracellular cAMP. In this study, we examined the role of PGD(2) and DP receptors in regulating human penile smooth muscle contractility. We determined that human corpus cavernosum tissue and smooth muscle cells in culture expressed functional DP receptor and lipocalin-like prostaglandin D synthase by reverse-transcribed polymerase chain reaction (RT-PCR). Functional PGD synthase activity was confirmed by the synthesis of PGD(2) in human corpus cavernosum smooth muscle cells upon addition of exogenous arachidonic acid. Organ bath preparations of human corpus cavernosum tissue strips, contracted with phenylephrine, relaxed in a dose-dependent fashion to either PGD(2) or the DP selective agonist BW245C. Cultures of human corpus cavernosum smooth muscle cells treated with BW245C showed a two-fold increase in cAMP synthesis. These data are consistent with the expression of functional DP receptors in human corpus cavernosum. This suggests the presence of an intact prostanoid autocrine system that may play a role in regulating penile erectile function.

Bridged Bicyclo Compounds, Heterocyclic↗
PubMed2002

Cerebellar growth in normal fetuses of multiple gestations.

OBJECTIVE: The purpose of this study was to compare the cerebellar growth in twin and triplet gestations with cerebellar growth in singleton pregnancies. METHODOLOGY: An ultrasound study was conducted in a population of normal pregnant women with singleton, twin and triplet gestations. Routine ultrasound examinations were performed in healthy pregnant women: 951 women with singleton pregnancies; 151 with twin gestations; and 28 with triplet gestations. Although multiple biometric parameters were measured throughout the course of pregnancy, in this study a single measurement (the last measurement before delivery) of the transverse cerebellar diameter (TCD) was used from each patient for statistical analysis. Growth of the TCD was determined in the multiple gestations and compared with growth in singleton pregnancies. RESULTS: A statistically significant relationship was found between TCD and gestational age in all three groups (singleton, twin A and B, and triplets) respectively: R2 = 0.963; R2 = 0.980; R2 = 0.977. No statistical difference was found between the three sets of normative measurements. CONCLUSIONS: There was no significant difference observed in cerebellar growth among singleton and multiple gestations. Therefore, nomograms previously established for singleton pregnancies may be useful to assess growth in multifetal pregnancies.

Adolescent↗
PubMed2001

Induction of TCR Vbeta-specific CD8+ CTLs by TCR Vbeta-derived peptides bound to HLA-E.

Previous studies have identified murine and human regulatory CD8+ T cells specific for TCR-Vbeta families expressed on autologous activated CD4+ T cells. In the mouse, these regulatory CD8+ T cells were shown to be restricted by the MHC class Ib molecule, Qa-1. In the present study, we asked whether HLA-E, the human functional equivalent of Qa-1, binds Vbeta peptides and whether the HLA-E/Vbeta-peptide complex induces and restricts human CD8+ CTLs. We first created stable HLA-E gene transfectants of the C1R cell line (C1R-E). Two putative HLA-E binding nonapeptides identified in human TCR Vbeta1 and Vbeta2 chains (SLELGDSAL and LLLGPGSGL, respectively) were shown to bind to HLA-E. CD8+ T cells could be primed in vitro by C1R-E cells loaded with the Vbeta1 (C1R-E/V1) or Vbeta2 (C1R-E/V2) peptide to preferentially kill C1R-E cells loaded with the respective inducing Vbeta peptide, compared with targets loaded with the other peptides. Priming CD8+ T cells with untreated C1R-E cells did not induce Vbeta-specific CTLs. Of perhaps more physiological relevance was the finding that the CD8+ CTLs primed by C1R-E/V1 also preferentially killed activated autologous TCR Vbeta1+. Similar results were observed in reciprocal experiments using C1R-E/V2 for priming. Furthermore, anti-CD8 and anti-MHC class I mAbs inhibited this Vbeta-specific killing of C1R-E and CD4+ T cell targets. Taken together, the data provide evidence that certain TCR-Vbeta peptides can be presented by HLA-E to further induce Vbeta-specific CD8+ CTLs.

CD4-Positive T-Lymphocytes↗