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P Cohen

Publications and source records attributed to P Cohen.

At least 127 records · Page 7Linked to original sources
PubMed2000

Role of insulin-like growth factors and their binding proteins in growth control and carcinogenesis.

Interest in the role of the insulin-like growth factor (IGF) axis in growth control and carcinogenesis has recently been increased by the finding of elevated serum insulin-like growth factor I (IGF-I) levels in association with three of the most prevalent cancers in the United States: prostate cancer, colorectal cancer, and lung cancer. IGFs serve as endocrine, autocrine, and paracrine stimulators of mitogenesis, survival, and cellular transformation. These actions are mediated through the type 1 IGF-receptor (IGF-1R), a tyrosine kinase that resembles the insulin receptor. The availability of free IGF for interaction with the IGF-1R is modulated by the insulin-like growth factor-binding proteins (IGFBPs). IGFBPs, especially IGFBP-3, also have IGF-independent effects on cell growth. IGF-independent growth inhibition by IGFBP-3 is believed to occur through IGFBP-3-specific cell surface association proteins or receptors and involves nuclear translocation. IGFBP-3-mediated apoptosis is controlled by numerous cell cycle regulators in both normal and disease processes. IGFBP activity is also regulated by IGFBP proteases, which affect the relative affinities of IGFBPs, IGFs and IGF-1R. Perturbations in each level of the IGF axis have been implicated in cancer formation and progression in various cell types.

Animals↗
PubMed2000

Efficacy and safety of diacerein in osteoarthritis of the knee: a double-blind, placebo-controlled trial. The Diacerein Study Group.

OBJECTIVE: To evaluate the efficacy and safety of diacerein, a drug with interleukin-1beta--inhibitory activity in vitro, in patients with knee osteoarthritis (OA). METHODS: A total of 484 patients fulfilling the American College of Rheumatology criteria for knee OA were enrolled in this 16-week, randomized, double-blind, placebo-controlled, parallel study group with 3 diacerein dosages of 50 mg/day, 100 mg/day, and 150 mg/day (administered twice daily). RESULTS: In the intent-to-treat population, 100 mg/day diacerein (50 mg twice daily) was significantly superior (P < 0.05) to placebo using the primary criterion (visual analog scale [VAS] assessment of pain on movement). Significant improvement (P < 0.05) was also observed for the secondary criteria, which included the Western Ontario and McMaster Universities OA Index (WOMAC), the WOMAC subscores, and the VAS assessment of handicap. In patients treated with diacerein dosages of 50 mg/day and 150 mg/day, favorable but not significant results were observed for the primary criterion. The best daily dosage of diacerein, calculated from the effect on the VAS assessment of pain on movement, was 90.1 mg. In the per-protocol population, the analysis of the primary criterion showed significant dose-dependent differences (P < 0.05) between each of the 3 diacerein dosages and the placebo. No differences were observed among the 3 diacerein groups. A significantly higher incidence (P < 0.05) of adverse events (AEs), as well as a higher rate of dropoout due to AEs, was observed in patients treated with 150 mg/day diacerein versus those treated with placebo, 50 mg/day diacerein, or 100 mg/day diacerein. Mild-to-moderate transient changes in bowel habits were the most frequent AEs, increasing with the dosage. CONCLUSION: Diacerein, a drug for the treatment of OA, was shown to be an effective treatment for symptoms in patients with knee OA. Taking into account both efficacy and safety, the optimal daily dosage of diacerein for patients with knee OA is 100 mg/day (50 mg twice daily).

Adult↗
PubMed2000

Usefulness of simultaneous detection of toxin A and glutamate dehydrogenase for the diagnosis of Clostridium difficile-associated diseases.

The aim of this study was to evaluate an immunoassay (Triage; Biosite Diagnostics, BMD, France) for detecting both a specific antigen of Clostridium difficile (glutamate dehydrogenase [GDH]) and toxin A. Evaluation of the test was carried out in 304 fecal samples from patients suspected of having Clostridium difficile-associated diseases. The results with GDH and toxin A were compared with those of a culture and cytotoxicity assay (toxin B). The prevalence rates for toxin B-positive and culture-positive fecal samples were 11.2% and 25%, respectively. The sensitivity of the Triage immunoassay was 90.8% for GDH and 79.4% for toxin A. A negative result with both toxin A and GDH was very reliably able to eliminate a diagnosis of Clostridium difficile-associated disease (negative predictive value 99.6%). Triage is a very rapid (20 min) and easy-to-perform test. It could be useful for diagnostic purposes and also for detecting nontoxigenic strains in epidemiogical studies.

Bacterial Proteins↗
PubMed2000

[Filling of bone defects with tricalcium phosphate beta in traumatology].

AIM OF STUDY: Synthetic bone substitutes like calcium phosphate ceramics have been used in orthopaedic surgery for several years. The aim of this study was to assess the results of the use of tricalcium phosphate beta for filling bone defects in trauma cases. PATIENTS AND METHOD: beta tricalcium phosphate was used in 24 trauma cases. The GESTO classification (Association pour l'étude des Greffes et Substituts Tissulaires en Orthopédie) and a qualitative scale were used to estimate the integration. RESULTS: With a mean follow-up of 20 months, integration was excellent in 41.2%, good in 29.2% and moderate in 17.4%. No fibrous encapsulation was observed around the implants in any case. Sepsis occurred in 3 cases with open fractures. CONCLUSION: beta-Tricalcium phosphate seems in our experience to be an excellent bone substitute for filling bone defects in trauma cases.

Adult↗
PubMed2000

The regulation of protein function by multisite phosphorylation--a 25 year update.

The phosphorylation of a protein can alter its behaviour in almost every conceivable way. These include modulation of its intrinsic biological activity, subcellular location, half-life and docking with other proteins. 'Multisite phosphorylation can enable several such effects to operate in the same protein. It can also determine the extent and duration of a response and is the key to signal integration.

Cations↗
PubMed2000

Individual latent growth curves in the development of marijuana use from childhood to young adulthood.

The present study was designed to examine the relationship between unconventionality and marijuana use over time. The sample for this paper consisted of 532 male and female participants interviewed during early adolescence, late adolescence, their early twenties, and their late twenties. Latent growth modeling was used. The findings indicated that (1) the influence of initial unconventionality (T2) on initial marijuana use (T2) was stronger for males, (2) unconventionality at T2 was not significantly related to overall rate of growth in marijuana use, and (3) change in unconventionality was related to overall growth rate of marijuana use. The implications of the findings for prevention and treatment are discussed.

Adolescent↗
PubMed2000

Age-related change in personality disorder trait levels between early adolescence and adulthood: a community-based longitudinal investigation.

OBJECTIVE: To investigate change in personality disorder (PD) traits between early adolescence and early adulthood among individuals in the community. METHOD: PD traits were assessed in 1983 (mean age = 14), 1985-86 (mean age = 16) and 1992 (mean age = 22) in a representative community sample of 816 youths. RESULTS: Overall, PD traits declined 28% during both adolescence and early adulthood. PD traits were moderately stable during the first 2-year interval, and were as stable as they have been reported to be among adults over similar intervals. PD trait stability declined slightly as the inter-assessment interval increased. Adolescents with PDs tended to have elevated PD traits during early adulthood. CONCLUSION: PD traits tend to decline steadily in prevalence during adolescence and early adulthood. However, adolescents with PDs often have elevated PD traits as young adults, and the stability of PD traits appears to be similar during adolescence and early adulthood.

Adolescent↗
PubMed2000

Favourable side-chain orientation of cleavage site dibasic residues of prohormone in proteolytic processing by prohormone convertase 1/3.

Previous studies using selectively modified pro-ocytocin/neurophysin substrate analogues and the purified metalloprotease, pro-ocytocin/neurophysin convertase (magnolysin; EC 3.4 24.62), have shown that dibasic cleavage site processing is associated with a prohormone sequence organized in a beta-turn structure. We have used various peptide analogues of the pro-ocytocin-neurophysin processing domain, and recombinant prohormone convertase 1/3, to test the validity of this property towards this member of the family of prohormone convertases (PCs). The enzymatic cleavage analysis and kinetics showed that: (a) with methyl amide (N-Met) modification, a secondary structure beta-turn breaker, the enzyme substrate interaction was abolished; (b) cleavage was favoured when the dibasic substrate side-chains were oriented in opposite directions; (c) the amino acid present at the P'1 position is important in the enzyme-substrate interaction; (d) the flexibility of the peptide substrate is necessary for the interaction; (e) Addition of dimethylsulfoxide to the cleavage assay favoured the cleavage of the pro-ocytocin/neurophysin large substrate over that of the smaller one pGlu-Arg-Thr-Lys-Arg-methyl coumarin amide. These data allowed us to conclude that proteolytic processing of pro-ocytocin-related peptide substrates by PC1/3 as well as by the metalloenzyme, magnolysin, involves selective recognition of precise cleavage site local secondary structure by the processing enzyme. It is hypothesized that this may represent a general property of peptide precursor proteolytic processing systems.

Amino Acid Sequence↗
PubMed2000

Does the GH-IGF axis play a role in cancer pathogenesis?

Recent case-controlled studies have found increases in the serum levels of insulin-like growth factor-I (IGF-I) in subjects who had, or who eventually developed, prostate or premenopausal breast cancers. Since growth hormone (GH) increases IGF-I levels, concern has been raised regarding its potential role as a cancer initiation factor. The epidemiological studies, which indicate an association between serum IGF-I levels and cancer risk, have not established causality. In fact, several alternative explanations for the elevated serum IGF-I levels in cancer patients may be proposed based on human and animal models. First, an effect of IGF-I causing symptomatic benign tissue hyperplasia may result in an ascertainment bias leading to an initiation of procedures resulting in the diagnosis of asymptomatic cancers. Second, elevated serum IGF-I in cancer patients may originate within the tumor (as suggested by some animal studies). Thirdly, serum IGF-I may actually be a surrogate marker of tissue IGF-I levels or of nutritional factors, which are not under GH control and may be involved in cancer initiation. The role of GH in cancer initiation is further negated by the fact that in acromegaly, the incidence of cancer, other than possibly colonic neoplasia does not appear to be significantly increased. Furthermore, GH transgenic mice, with high IGF-I levels, do not develop breast, prostate, or colonic malignancies. It is known that IGFBP-3 can inhibit IGF action on cancer cells in vitro and also can induce apoptosis via an IGF-independent mechanism. Importantly, in addition to increasing IGF-I levels, GH also increases the serum levels of IGFBP-3 and serum IGFBP-3 levels have been shown to be negatively correlated with the risk of cancer in the above mentioned epidemiological studies and in a similar study on colon cancer. These studies suggest that cancer risk is increased in individuals in whom both high IGF-I levels and low IGFBP-3 levels are present. In subjects treated with GH, IGF-I and IGFBP-3 levels both rise together and are not within the elevated cancer-risk range, based on published studies. Long-term studies are needed to assess the potential risks, including the long-term cancer risk associated with GH therapy. These should take into account several factors, including the duration of exposure, the risk magnitude associated with the degree of serum IGF-I elevation, and the adjusted risk based on a concomitant increase in IGFBP-3 levels. Since GH treated patients often have sub-normal IGF-I serum levels, which normalize on therapy, one might predict that their cancer risk on GH therapy should not increase above the normal population. Until further research in the area dictates otherwise, on-going cancer surveillance and routine monitoring of serum IGF-I and IGFBP-3 levels in GH-recipients should be the standard of care. At present, the data that are available do not warrant a change in our current management of approved indications for GH therapy.

Animals↗
PubMed2000

Longitudinally foretelling drug use in the late twenties: adolescent personality and social-environmental antecedents.

This research focuses on the interrelation of the parent-child attachment, unconventionality, friends' drug use, and the young adult's use of drugs. Data were collected from participants at 4 points in time: early adolescence, late adolescence, early 20s, and late 20s. Data were collected from mothers at the 3 points in time that corresponded with the first 3 collections of data from their children. Both the youths and their mothers were individually interviewed. The findings indicated that the effect of parent-child mutual attachment was mediated through early adolescent personality attributes of greater responsibility, less rebelliousness, and intolerance of deviance. These non-drug-prone personality and behavioral attitudes, in turn, insulated the young adult from affiliating with drug-using peers, and these attitudes were related to less drug use in the early 20s and ultimately in the late 20s. The results suggest that interventions focused on enhancing parent-child mutual attachment should result in a reduction of the risk factors conducive to drug use during the late 20s. The fact that these findings cover a decade and a half, from early adolescence to the late 20s, underscores the significance of placing drug use in a perspective that includes familial and behavioral aspects.

Adolescent↗
PubMed2000

How specific is specific impairment?

OBJECTIVE: To describe the usefulness of impairment items placed at the end of each diagnostic section of a structured instrument (the Diagnostic Interview Schedule for Children Version 2.3) in an attempt to link impairment to specific diagnoses. METHOD: Data from 3 sites of the Methods for the Epidemiology of Child and Adolescent Mental Disorders Study were used to assess the reliability of the specific impairment measures by diagnosis, the extent to which global and specific measures of impairment impact on prevalence rates, the concordance between global and specific impairment, and the degree to which there may be a "halo effect" among specific impairment ratings. RESULTS: Test-retest reliability was better for parent than youth ratings. Fewer children were rated as impaired on well-validated global scales than on specific impairment ratings, suggesting that the threshold for specific ratings needs to be reevaluated. Agreement between specific and global ratings was poor. Most subjects with 2 or more diagnoses for which impairment was attributed to one diagnosis also had impairment attributed to other diagnoses for which they met symptom criteria, suggesting a halo effect in these ratings of specific impairment. CONCLUSIONS: Impairment measures are important in diagnostic assessments to distinguish those individuals whose psychopathology is of clinical significance. Specific impairment ratings used in structured instruments could be improved by including parameters of impairment that are diagnosis-specific.

Adolescent↗
PubMed2000

Extrahepatic manifestations associated with hepatitis C virus infection. A prospective multicenter study of 321 patients. The GERMIVIC. Groupe d'Etude et de Recherche en Medecine Interne et Maladies Infectieuses sur le Virus de l'Hepatite C.

From January 1996 to January 1997, 321 patients with an average age of 46 +/- 16 years and chronically infected with hepatitis C virus (HCV) were prospectively enrolled in a study designed to determine the prevalence of extrahepatic manifestations associated with HCV infection in a large cohort of HCV patients, to identify associations between clinical and biologic manifestations, and to compare the results obtained in human immunodeficiency virus (HIV)-positive versus HIV-negative subsets. In a cross-sectional study, clinical extrahepatic manifestations, viral coinfections with HIV and/or hepatitis B virus, connective tissue diseases, and a wide panel of autoantibodies were assessed. Thirty-eight percent (122/321) of patients presented at least 1 clinical extrahepatic manifestation including arthralgia (60/321, 19%), skin manifestations (55/321, 17%), xerostomia (40/321, 12%), xerophthalmia (32/321, 10%), and sensory neuropathy (28/321, 9%). Main biologic abnormalities were mixed cryoglobulins (110/196, 56%), thrombocytopenia (50/291, 17%), and the presence of the following autoantibodies: antinuclear (123/302, 41%), rheumatoid factor (107/280, 38%), anticardiolipin (79/298, 27%), antithyroglobulin (36/287, 13%) and antismooth muscle cell (27/288, 9%). At least 1 autoantibody was present in 210/302 (70%) of sera. By multivariate logistic regression analysis, 4 parameters were significantly associated with cryoglobulin positivity: systemic vasculitis (p = 0.01, odds ratio OR[ = 17.3), HIV positivity (p = 0.0006, OR = 10.2), rheumatoid factor positivity (p = 0.01, OR = 2.8), and sicca syndrome (p = 0.03, OR = 0.27). A definite connective tissue disease was noted in 44 patients (14%), mainly symptomatic mixed cryoglobulinemia and systemic vasculitis, HIV coinfection (23%) was associated with 3 parameters: anticardiolipin (p = 0.003, OR = 4.18), thrombocytopenia (p = 0.01, OR = 3.56), and arthralgia or myalgia (p = 0.017, OR = 0.23). HIV-positive patients presented more severe histologic lesions (p = 0.0004). Extrahepatic clinical manifestations in HCV patients involve primarily the skin and joints. The most frequent immunologic abnormalities include mixed cryoglobulins, rheumatoid factor, antinuclear, anticardiolipin, and antithyroglobulin antibodies. Cryoglobulin positivity is associated with systemic vasculitis and rheumatoid factor and HIV positivity. HIV coinfection is associated with arthralgia or myalgia, anticardiolipin antibodies, and thrombocytopenia.

Adolescent↗
PubMed2000

Insulin and insulin-like growth factor-I cause vasorelaxation in human vessels in vitro.

BACKGROUND: Insulin and insulin-like growth factor-I (IGF-I) are endogenous peptides with vasoactive activities. OBJECTIVE: To evaluate the vasodilatory effects of insulin and IGF-I on human vessels taken from patients with and without noninsulin-dependent diabetes mellitus (NIDDM) and to elucidate their mechanisms of action. METHODS: Vascular rings of human internal mammary artery (IMA) and saphenous vein harvested from 54 patients with and without NIDDM undergoing coronary bypass surgery were studied in vitro. RESULTS: For samples from patients without NIDDM both insulin and IGF-I (10(-12)-10(-7) mol/l) evoked greater relaxation in IMA rings (30 +/- 4 and 29 +/- 6%, maximal relaxation +/- SEM, respectively) than they did in saphenous-vein rings (43 +/- 4 and 42 +/- 5%, respectively, P < 0.05 both for insulin and for IGF-I). Similar results were obtained with vessels from patients with NIDDM. Relaxation was not affected by the removal of the endothelium and by inhibition of the production of nitric oxide. However, the vascular relaxation caused by insulin and IGF-I was completely abolished by KCI, and was attenuated by the nonspecific potassium-channel blocker tetraethylammonium (for IMA rings, to 77 +/- 8 and 66 +/- 4% with insulin and IGF-I, respectively; for saphenous vein rings, 73 +/- 2 and 77 +/- 1% for insulin and IGF-I, respectively, P < 0.001). CONCLUSIONS: Both insulin and IGF-I induced endothelial-independent, nitric oxide-independent vasorelaxation of rings from human IMA and saphenous veins, through a mechanism involving activation of potassium channels. This response remained intact in vessels from patients with NIDDM. This result supports the hypothesis that insulin and IGF-I play roles in the regulation of vascular tone in human vessels.

Diabetes Mellitus, Type 2↗
PubMed2000

Cyclo-oxygenase-2 inhibitors ameliorate the severity of experimental colitis in rats.

BACKGROUND: Both in experimental colitis and in inflammatory bowel disease, colonic eicosanoid generation is enhanced and may contribute to the pathogenesis of the inflammatory response. AIMS: To evaluate the effect of selective cyclo-oxygenase-2 (COX-2) inhibitors on the extent and severity of two models of experimental colitis. METHODS: Colitis was induced by intra-caecal administration of 2 ml 5% acetic acid or intra-colonic administration of 0.1 ml 3% iodoacetamide. Rats were treated intra-gastrically with nimesulide 2 x 10 mg/kg/day, or once with SC-236 6 mg/kg, and killed 1 or 3 days after damage induction. The colon was isolated, weighed, macroscopic damage was measured, and mucosal samples were obtained for histology and for determination of myeloperoxidase (MPO) and nitric oxide synthase (NOS) activities and eicosanoid generation. The serum levels of thromboxane B2 (TXB2), tumour necrosis factor-alpha (TNF-alpha) and interleukin-1beta (IL-1beta) were determined. RESULTS: Nimesulide significantly decreased the extent of colitis induced by acetic acid. Both nimesulide and SC-236 significantly decreased the extent of iodoacetamide-induced colonic damage. The decrease in the extent of colitis induced by nimesulide was accompanied by a significant decrease in mucosal MPO and NOS activities. Nimesulide and SC-236 decreased the enhanced colonic eicosanoid generation in acetic acid and iodoacetamide-induced colitis, and, in iodoacetamide-treated rats, nimesulide also decreased the elevated serum TNF-alpha and IL-1beta levels. CONCLUSIONS: The effective nimesulide and SC-236-induced amelioration of the severity of the colitis in acetic acid and iodoacetamide-treated rats confirms the role of eicosanoids in their pathogenesis and suggests that COX-2 inhibitors may be of value in the treatment of inflammatory bowel disease.

Animals↗
PubMed2000

Social phobia and the persistence of conduct problems.

Recent epidemiological studies suggest that both social anxiety and attention deficit hyperactivity disorder (ADHD) in childhood might predict levels of delinquent behavior in adolescence. The current study prospectively examines the influence of social phobia and ADHD symptom scale scores on the correlation in conduct disorder symptom scale scores over time. An epidemiologically selected sample of 776 young people living in Upstate New York received DSM-based psychiatric assessments in 1983, 1985, and 1992 using structured interviews. Correlations among conduct disorder scales over time were examined as a function of social phobia and ADHD ratings. Individuals with low scores on social phobia scales or high scores on ADHD scales exhibited the highest correlation in conduct disorder symptom scales over time. There was also a suggestion that low scores on social phobia scales predicted later risk for conduct disorder. Low scores on social phobia symptom scales or high scores on ADHD scales predict stronger across-time correlations in conduct disorder symptom scales. Various cognitive or biological factors might account for these moderating effects on conduct problems.

Adolescent↗
PubMed2000

Human papillomavirus type 16 E7 oncoprotein binds and inactivates growth-inhibitory insulin-like growth factor binding protein 3.

The E7 protein encoded by human papillomavirus type 16 is one of the few viral genes that can immortalize primary human cells and thereby override cellular senescence. While it is generally assumed that this property of E7 depends on its interaction with regulators of the cell cycle, we show here that E7 targets insulin-like growth factor binding protein 3 (IGFBP-3), the product of a p53-inducible gene that is overexpressed in senescent cells. IGFBP-3 can suppress cell proliferation and induce apoptosis; we show here that IGFBP-3-mediated apoptosis is inhibited by E7, which binds to IGFBP-3 and triggers its proteolytic cleavage. Two transformation-deficient mutants of E7 failed to inactivate IGFBP-3, suggesting that inactivation of IGFBP-3 may contribute to cell transformation.

Apoptosis↗
PubMed2000

IGFBP-3 mediates TGF-beta1-induced cell growth in human airway smooth muscle cells.

Both insulin-like growth factor binding protein-3 (IGFBP-3) and transforming growth factor-beta (TGF-beta) have been separately shown to have cell-specific growth-inhibiting or growth-potentiating effects. TGF-beta stimulates IGFBP-3 mRNA and peptide expression in several cell types, and TGF-beta-induced growth inhibition and apoptosis have been shown to be mediated through the induction of IGFBP-3. However, a link between the growth stimulatory effects of TGF-beta and IGFBP-3-induction has not been shown. In this study, we investigated the role of IGFBP-3 in mediating TGF-beta1-induced cell growth using human airway smooth muscle (ASM) cells as our model. TGF-beta1 (1 ng/ml) treatment induced a 10- to 20-fold increase in the levels of expression of IGFBP-3 mRNA and protein. Addition of either IGFBP-3 or TGF-beta1 to the growth medium resulted in an approximately twofold increase in cell proliferation. Coincubation of ASM cells with IGFBP-3 antisense (but not sense) oligomers as well as with an IGFBP-3 neutralizing antibody (but not with control IgG) blocked the growth induced by TGF-beta1 (P < 0.001). Several IGFBP-3-associated proteins were observed in ASM cell lysates, which may have a role in the cellular responses to IGFBP-3. These findings demonstrate that IGFBP-3 is capable of mediating the growth stimulatory effect of TGF-beta in ASM cells.

Adolescent↗