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Biomedical subjects

P Cohen

Publications and source records attributed to P Cohen.

At least 37 records · Page 2Linked to original sources
PubMed2003

Neurophysiologic evidence for a central sensitization in patients with fibromyalgia.

OBJECTIVE: To determine whether abnormalities of peripheral and central nociceptive sensory input processing exist outside areas of spontaneous pain in patients with fibromyalgia (FM) as compared with controls, by using quantitative sensory testing (QST) and a neurophysiologic paradigm independent from subjective reports. METHODS: A total of 164 outpatients with FM who were attending a self-management program were invited to participate in the study. Data for 85 patients were available and were compared with those for 40 non-FM controls matched for age and sex. QST was performed using thermal, mechanical, and electrical stimuli at locations of nonspontaneous pain. Pain assessment was 2-fold and included use of subjective scales and the spinal nociceptive flexion reflex (NFR), a specific physiologic correlate for the objective evaluation of central nociceptive pathways. Questionnaires regarding quality of life and the impact of FM were available. RESULTS: Participants were mainly middle-aged women, with a mean disease duration of 8 years. Between-group differences were significant for neurophysiologic, clinical, and quality of life measures. In patients with FM, peripheral QST showed significantly altered cold and heat pain thresholds, and tolerance to cold pain was radically reduced. The median NFR threshold in patients with FM (22.7 mA [range 17.5-31.7]) was significantly decreased compared with that in controls (33 mA [range 28.1-41]). A cutoff value of <27.6 mA for NFR provided sensitivity of 73% and specificity of 80% for detecting central allodynia in the setting of FM. CONCLUSION: Our results strongly, although indirectly, point to a state of central hyperexcitability of the nociceptive system in patients with FM. The NFR can be used to assess central allodynia in FM. It may also help discriminate patients who may benefit from use of centrally acting analgesics.

Female↗
PubMed2003

[Systemic necrotizing vasculitides: classifications and therapeutic strategies].

OBJECTIVES: The knowledge of systemic necrotizing vasculitides improved since new classifications have been established along with a better understanding of pathogenesis of the diseases. The major vasculitides are described herein. CURRENT KNOWLEDGE AND KEY POINTS: Pathogenesis plays now a major role for classifying diseases and influences the diagnostic strategies. The prospective therapeutic trials established by French and European groups are largely based on our better knowledge of the diseases. FUTURE PROSPECTS AND PROJECTS: Despite the good results obtained with and demonstrated in prospective trials, the vasculitides remain severe and deserve new studies testing new drugs but also strategies based on prognostic factors and scores which should play a major role in treatments decision.

Clinical Trials as Topic↗
PubMed2002

[Efficacy of diacerein on the symptoms and radiographic progression of osteoarthritis].

SYMPTOMATIC EFFECTS OF DIACEREIN: Data obtained from several clinical trials have demonstrated that relief of joint pain obtained with the interleukin-1 inhibitor diacerein is comparable with that observed with non-steroidal anti-inflammatory drugs (NSAIDS) after four to six weeks of treatment and that relief persists after treatment withdrawal. Patients taking diacerein are less handicapped, use less NSAID and/or analgesics, and have lower demands for care as well as an improved quality of life. RADIOGRAPHIC FINDINGS: The ECHODIAH study conducted to evaluate the structure-modifying effect of diacerein in hip osteoarthritis. TOLERANCE: Drug watch data and clinical trials have confirmed the safety and tolerance of diacerein, so there is no limitation on the duration of its use.

Anthraquinones↗
PubMed2002

K+ channel activation by all three isoforms of serum- and glucocorticoid-dependent protein kinase SGK.

The serum- and glucocorticoid-dependent kinase SGK1 was originally identified as a glucocorticoid-sensitive gene. Subsequently, the two homologous kinases SGK2 and SGK3 have been cloned, being products of distinct genes, which are differentially expressed and share 80% identity in amino acid sequence in their catalytic domains. While SGK1 has been shown to activate ion channels, including K(+) channels, the functions of SGK2 and SGK3 have not been examined. The present study was therefore performed to elucidate the effect of SGK1, SGK2, and SGK3 on electrical properties of renal epithelial cells. To this end human embryonic kidney (HEK293) cells were transfected with the kinases and ion-channel activity determined using the patch-clamp technique. In non-transfected cells and in cells transfected with the empty GFP construct a voltage-gated K(+) current was observed amounting to 303+/-19 pA ( n=13) and 299+/-29 pA ( n=23), respectively. Transfection with SGK1, SGK2 or SGK3 increased the voltage-gated K(+) current to 1056+/-152 pA ( n=17), 555+/-47 pA ( n=17), and 775+/-98 pA ( n=16), respectively. The K(+) current was fully blocked by 3 mM tetraethylammonium chloride and inhibited 45% by the Kv1 channel blocker margatoxin (10 nM). In dual electrode voltage-clamp experiments SGK isoforms up-regulated Kv1 voltage-gated K(+)channels expressed in Xenopus laevis oocytes. The present observations thus reveal a powerful stimulating effect of all three isoforms of SGK on K(+) channels. Those effects may participate in regulation of epithelial transport, cell proliferation, and neuromuscular excitability.

Animals↗
PubMed2002

[Influence of testing position on lumbar isokinetic measurements].

UNLABELLED: The studies carried out on the lumbar spine, using an isokinetic type machine, showed the importance of the extensor muscles and the force they develop, compared with the flexor muscles. Both the sitting and standing positions were used without determining the better position. MAIN OBJECTIVE OF THE STUDY: To determine how the patients position influenced the performance of the muscles. We also studied a new parameter : the angle to maximal peak torque (APT). MATERIAL AND METHOD: 17 healthy subjects and 19 suffering from low back pain were chosen. We perform the test in both positions for each subject. We compare in each group the peak torque of the extensor and flexor muscles on both positions and the angle of this torque. RESULTS: Low back pain subjects flexor/extensor ratio were 1.71 sitting and 1.56 standing. Healthy subjects showed normal ratio of 0.69 and 0.84. CONCLUSION: The position of the subject has no influence on the results in the low back pain subjects, and the sitting position is preferred. The angle of development of the maximal peak torque in both groups of muscles was very interesting, especially in the subjects suffering from low back pain and shines a new light on the different functions of the muscles of the low back pain suffering subjects and the healthy subjects. This angle (APT) is inversed in low back pain subjects who develop more torque for the extensors in extension of the spine.

Adult↗
PubMed2002

ED(27) trophoblast-like cells isolated from first-trimester chorionic villi are genetically identical to HeLa cells yet exhibit a distinct phenotype.

ED(27) trophoblast-like cells were prepared from human chorionic villus samples obtained at 9 weeks gestation and have been grown continuously in vitro without phenotypic drift for nearly a decade. These cells express many trophoblast markers, including cytokeratin, placental alkaline phosphatase (PLAP), secretion of 17beta-estradiol, and a microvillous apical surface. The ED(27) cell line is a useful model system for studies of placental cell biology and has been distributed to laboratories world-wide. However, experiments to investigate their relationship to primary villous cytotrophoblast have shown that these cells do not secrete detectable amounts of human chorionic gonadotropin in culture and, when digested with trypsin, disperse into individual cells. Furthermore, immunocytochemical studies demonstrated that, unlike villous cytotrophoblasts, ED(27) cells were immunoreactive with monoclonal antibodies recognizing some HLA Class I antigens. This was not HLA-G, however, as would be expected if these cells originated from extravillous cytotrophoblasts, but rather classical HLA-A, B which is thought not to be expressed by any trophoblast subpopulations. These inconsistencies prompted us to question the authenticity of the continuous cell line as it now exists. Genetic haplotype analysis using the polymerase chain reaction (PCR) revealed that ED(27) was genetically identically to the HeLa cell line. Inasmuch as HeLa cells have never been grown in the laboratory (DAK), the only possible origin of HeLa cell contamination of ED(27) cells was the WISH cell line, and further PCR analysis revealed that this cell line was also genetically identical to HeLa. Like ED(27) cells, HeLa cells and WISH cells synthesized small amounts of estrogen and were found to express PLAP and antigens recognized by the monoclonal antibodies ED822, directed against the syncytiotrophoblast, and J1B5 directed against villous cytotrophoblast. These results point out the need for adherence to rigorous and consistent quality control measures to assure the authenticity of cell lines used as in vitro model systems.

Adult↗
PubMed2002

Efficacy of the anti-TNF-alpha antibody infliximab against refractory systemic vasculitides: an open pilot study on 10 patients.

OBJECTIVE: Evidence indicates that tumour necrosis factor (TNF) is a major agent in the pathogenesis of vasculitis. We studied the short-term effect of anti-TNF-alpha antibody in systemic vasculitis patients refractory to steroids and immunosuppressive agents. METHODS: Ten patients refractory to corticosteroids and at least one immunosuppressant and who had persistently active disease or a new flare were included. Seven had Wegener's granulomatosis, two had rheumatoid arthritis-associated vasculitis and one had cryoglobulinaemia with mean duration of 9.1, 21.5 and 17 yr. They received infliximab (5 mg/kg) on days 1, 14, 42 and then every 8 weeks. Immunosuppressants were stopped between days 0 and 42 for eight patients, while the steroid dose was maintained or lowered. The treatment response was evaluated clinically with the Birmingham Vasculitis Activity Score 2000 (BVAS). RESULTS: Complete or partial remission was observed in all patients. The mean BVAS at entry was 9.1 (range 4-15) and had declined to 1.9 (range 0-4) by day 42 and 1.3 (range 0-4) at 6 months; BVAS of 0 was recorded for four patients on day 42 and for five at 6 months. The only adverse effect was cutaneous eruption in two patients. CONCLUSION: Anti-TNF-alpha successfully induced prompt symptomatic responses in patients with systemic vasculitis not responding to conventional treatment. Infliximab was well tolerated during the short-term follow-up.

Adult↗
PubMed2002

Characteristics and outcome of 49 patients with symptomatic cryoglobulinaemia.

OBJECTIVE: To describe a population of patients with symptomatic cryoglobulinaemia, comparing manifestations and outcome as a function of hepatitis C virus (HCV) status. PATIENTS AND METHODS: A retrospective study on 179 patients who tested positive for cryoglobulins, seen between 1978 and 1998 in an internal medicine department. RESULTS: Among 179 cryoglobulin-positive patients, only 49 (18 men, 31 women; mean age 59.96+/-12 yr) had clinical manifestations attributable to cryoglobulinaemia. Thirty-three had HCV infection, 20 had systemic autoimmune diseases, two had haematological diseases, one had human immunodeficiency virus and HCV co-infection, one had HCV and HBV co-infection and six had essential mixed cryoglobulinaemia. The clinical manifestations and cryoglobulin levels in HCV(+) and HCV(-) patients did not differ significantly. Only arthralgias and elevated transaminases were significantly more frequent in HCV(+) patients (P<0.02 and <0.05, respectively). Five-year survival rates were comparable for HCV(+) and HCV(-) patients. Eight patients died (six HCV(+), two HCV(-)), with a median time between diagnosis and death of 38.7 months. CONCLUSION: Clinical manifestations of cryoglobulinaemia, except arthralgias, were comparable for HCV(+) and HCV(-) patients. When systemic manifestations are present, the prognosis is poor despite intensive or prolonged therapy.

Cryoglobulinemia↗
PubMed2002

Churg-Strauss syndrome in two patients receiving montelukast.

OBJECTIVE: Churg-Strauss syndrome (CSS) has been described in association with the treatment of asthmatic patients with leukotriene receptor antagonist. The main mechanism proposed to explain this condition is the unmasking of CSS after the leukotriene receptor antagonist has allowed corticosteroid tapering. Other hypotheses might be proposed. METHODS: We describe two patients who developed CSS after starting treatment with montelukast, a new antileukotriene drug. RESULTS: Both patients presented with CSS after 4-5 months of treatment with montelukast. Neither patient received long-term systemic steroids for asthma, but both were on inhaled steroids. One patient had a myocardial involvement and experienced a stroke. Our two patients were treated with systemic steroids and cyclophosphamide. CONCLUSIONS: CSS does not appear to relate to steroid tapering in our patients. The other hypotheses are a coincidence or a direct adverse effect of the antileukotriene. Long-term data on these drugs are lacking and leukotriene's role in vasculitis remains to be elucidated.

Acetates↗
PubMed2002

Magnetic resonance imaging of skeletal muscle involvement in limb restricted vasculitis.

BACKGROUND: Limb restricted polyarteritis nodosa (PAN) and PAN-type diseases such as isolated vasculitis of skeletal muscle are localised vasculitides affecting the skin, muscles, or peripheral nerves, usually of the lower limbs. These diseases often present with non-specific clinical symptoms and normal laboratory values and electromyograms. The usefulness of magnetic resonance imaging (MRI) of skeletal muscle has been poorly investigated to date. OBJECTIVE: To describe the MRI findings in the legs of three patients with limb restricted vasculitides (two PAN, one isolated vasculitis of the skeletal muscle) with histologically established muscle involvement. METHODS: MRI was carried out on calf muscles and T(2) weighted images, unenhanced T(1) weighted images, and STIR sequences were obtained. RESULTS: Muscle damage resulted in oedema-like changes on MRI characterised by hyperintense signals in T(2) weighted and slow tau inversion recovery (STIR) sequences and normal unenhanced T(1) weighted sequences of one or several leg muscles. CONCLUSIONS: MRI should be considered a useful complementary examination that might facilitate the recognition of limb restricted vasculitides, and possibly indicate the site for muscle biopsy. It could also be useful in monitoring the course of the disease. Future studies should also evaluate MRI for systemic PAN or other systemic vasculitides with muscle involvement.

Adult↗
PubMed2002

Which measure of adolescent psychiatric disorder--diagnosis, number of symptoms, or adaptive functioning--best predicts adverse young adult outcomes?

OBJECTIVE: To test the ability of psychiatric diagnosis, symptom count, and adaptive functioning in adolescence to predict failure to complete secondary school and criminal involvement in young adulthood. DESIGN: Community-based cohort study. SETTING: Two counties in upstate New York, USA. PARTICIPANTS: 181 adolescents interviewed in 1983 and 1985-86 who were randomly selected in 1975 from a probability area sampling of representative families with 1-10 year old children. MAIN RESULTS: Compared with adolescents without psychiatric disorders, adolescents with depressive, anxiety, disruptive, and substance abuse disorders were 2.86-9.21 times more likely to fail to complete secondary school. Compared with adolescents without disruptive disorders, adolescents with disruptive disorders were 4.04 (1.96-8.32) times more likely to get in trouble with police during young adulthood. The positive predictive value of each measure of adolescent psychiatric disorder for school non-completion was higher in the lowest SES stratum and for young adult criminal involvement was higher for boys. Combining knowledge of symptom counts, age, gender, and social class in a logistic regression model yielded 89% sensitivity and 87% specificity for predicting future school non-completion at the p >or= 0.13 cut off. The optimal cut off value in a model incorporating knowledge of disruptive symptoms and demographic characteristics yielded 75% sensitivity and 76% specificity for predicting future criminal involvement. CONCLUSIONS: Screening children and adolescents for psychiatric disorders can identify those at high risk of adverse young adult outcomes. Future school and community adjustment can be predicted as easily and accurately on the basis of a simple count of psychiatric symptoms as by applying more complex diagnostic algorithms. Screening youth for psychiatric symptoms in neighbourhood, school, or primary care settings is a logical first step for early intervention to promote increased school completion and decreased criminal activity in young adulthood.

Achievement↗
PubMed2002

Nuclear effects: unexpected intracellular actions of insulin-like growth factor binding protein-3.

Insulin-like growth factor (IGF) binding protein (IGFBP)-3 has been shown to be a growth inhibitory, apoptosis-inducing molecule by virtue of its ability to bind IGFs, in addition to previously demonstrated IGF-independent effects. The recent discovery of the interaction between nuclear IGFBP-3 and 9-cis retinoic acid receptor-alpha (retinoid X receptor alpha RXRalpha), a nuclear receptor, and its involvement in the regulation of transcriptional signaling and apoptosis represents an important paradigm shift in the understanding of IGFBP function. RXRalpha is required for the apoptosis-inducing effects of IGFBP-3. IGFBP-3 and RXR ligands are additive in inducing apoptosis in cancer cells. IGFBP-3 has direct effects on gene transcription, as RXR response element reporter signaling was enhanced and the all-trans retinoic acid receptor response element reporter signaling was inhibited. Accumulating evidence further confirms IGF-independent functions of this multifunction binding protein. Other binding proteins, in addition to other members of the IGF axis, have now been described in the nucleus and are postulated to have effects on transcriptional events. Investigation into these new interactions will expose new protein partners in the interface between the nuclear receptor and growth factor pathways and reveal new targets to be exploited in the treatment of cancer and other diseases.

Animals↗
PubMed2001

IGF-1 up-regulates K+ channels via PI3-kinase, PDK1 and SGK1.

Involvement of voltage-gated (Kv) potassium channels in IGF-1-induced proliferation of HEK293 cells was studied by patch-clamp, RT-PCR and FACS analysis. IGF-1 up-regulated outwardly rectifying whole-cell K+ current starting after 1 h of incubation and reaching a maximum after 4-6 h. The IGF-1-stimulated current was voltage-gated with an activation threshold of -30 mV to -40 mV, a half-maximal activation at +5.3+/-1.8 mV, and time constants for activation and inactivation of 4.5+/-0.4 ms and 43.5+/-5.6 ms ( n=10), respectively. The current was inhibited by TEA, margatoxin, agitoxin-2 and stichodactyla toxin. PCR amplification of different Kv subunits from HEK293 cDNA demonstrated the expression of Kv1.1, Kv1.2, Kv1.3, Kv1.4, Kv3.1 and Kv3.4 mRNA. Quantitative RT-PCR showed up-regulation of Kv1.1, 1.2 and 1.3 mRNA by IGF-1. The effect of IGF-1 on K+ current was blocked by inhibitors of phosphatidylinositol 3-kinase (PI3-kinase), wortmannin and LY294002, and mimicked by overexpression of human 3-phosphoinositide-dependent protein kinase-1 (hPDK1) or serum- and glucocorticoid-dependent kinase-1 (hSGK1), both sequential downstream targets of PI3-kinase. IGF-1-induced proliferation of HEK293 cells was inhibited by both K+ channel blockers and inhibitors of PI3-kinase. In conclusion, IGF-1 through PI3-kinase, PDK1 and SGK1 up-regulates Kv channels, an effect required for the proliferative action of the growth factor.

3-Phosphoinositide-Dependent Protein Kinases↗
PubMed2001

Regulation and physiological roles of serum- and glucocorticoid-induced protein kinase isoforms.

Serum- and glucocorticoid-induced protein kinase 1 (SGK1) was identified in 1993 as an immediate early gene whose mRNA levels increase dramatically within 30 minutes when cells are exposed to serum or glucocorticoids, or both. Subsequently, many other agonists, acting through a variety of signal transduction pathways, have been shown to induce SGK1 gene transcription in cells and tissues. SGK1 is a member of the "AGC" subfamily, which includes protein kinases A, G, and C, and its catalytic domain is most similar to protein kinase B (PKB). Like PKB, SGK1 is activated by phosphorylation in response to signals that stimulate phosphatidylinositol 3-kinase, and this is mediated by 3-phosphoinositide-dependent protein kinase 1 (PDK1) and another protein kinase that has yet to be identified. Thus, SGK1 is remarkable in being activated at both the transcriptional and posttranslational levels by a huge number of extracellular signals. In contrast, little is known about the transcriptional regulation of the two closely related isoforms SGK2 and SGK3, although they can be activated by phosphorylation. The substrate specificity of SGK isoforms superficially resembles that of PKB in that serine and threonine residues lying in Arg-Xaa-Arg-Xaa-Xaa-Ser/Thr sequences (where Xaa is a variable amino acid) are phosphorylated. However, although they may have some substrates in common, evidence is emerging that SGK1 and PKB phosphorylate distinct proteins and have different functions in vivo. In particular, SGK1 plays an important role in activating certain potassium, sodium, and chloride channels, suggesting an involvement in the regulation of processes such as cell survival, neuronal excitability, and renal sodium excretion. Moreover, sustained high levels of SGK1 protein and activity may contribute to conditions such as hypertension and diabetic nephropathy. This raises the possibility that specific inhibitors of SGK1 may have therapeutic potential for the treatment of several diseases.

Amino Acid Sequence↗
PubMed2001

Adolescent fears as predictors of depression.

BACKGROUND: Recent studies raise questions on the relationship between adolescent fears and risk for major depression. METHODS: An epidemiologic sample of 776 young people received psychiatric assessments in 1983, 1985-1986, and 1992. Prospective associations were examined between fears in adolescence and future episodes of major depression. RESULTS: Both overall level of fears and specific fear of dark in adolescence predicted future risk for major depression. CONCLUSIONS: Relatively high levels of fear in adolescence represent a risk factor for later episodes of major depression.

Adolescent↗
PubMed2001

Antiischemic effects of SB203580 are mediated through the inhibition of p38alpha mitogen-activated protein kinase: Evidence from ectopic expression of an inhibition-resistant kinase.

The aim of the present study was to determine whether the attenuation of myocardial ischemic injury by SB203580 is due to the inhibition of p38 mitogen-activated protein kinase (MAPK) or to other documented nonspecific effects of the drug. We made adenoviral vectors encoding the alpha isoform of p38 MAPK with or without site-directed mutations to prevent SB203580 binding and inhibition. In embryonal rat heart-derived cells and adult rat cardiocytes expressing wild-type p38alpha MAPK, injury was reduced significantly by SB203580 present during simulated ischemia. In contrast, SB203580 did not protect cells expressing the SB203580-resistant form of p38alpha MAPK. These observations suggest that SB203580-mediated protection depends on the inhibition of p38alpha MAPK.

Adenoviridae↗
PubMed2001

The induction of cyclooxygenase-2 mRNA in macrophages is biphasic and requires both CCAAT enhancer-binding protein beta (C/EBP beta ) and C/EBP delta transcription factors.

Prostaglandins are important mediators of activated macrophage functions, and their inducible synthesis is mediated by cyclooxygenase-2 (COX-2). Here, we make use of the murine macrophage cells RAW264 as well as of immortalized macrophages derived from mice deficient for the transcription factor CCAAT enhancer-binding protein beta (C/EBP beta) to explore the molecular mechanisms regulating COX-2 induction in activated macrophages. We demonstrate that lipopolysaccharide-mediated COX-2 mRNA induction is biphasic. The initial phase is independent of de novo protein synthesis, correlates with cAMP-response element-binding protein (CREB) activation, is inhibited by treatments that abolish CREB phosphorylation and reduce NF-kappa B-mediated gene activation, and requires the presence of the transcription factor C/EBP beta. On the other hand, C/EBP delta appears to be essential in addition to C/EBP beta to effect the second phase of COX-2 gene transcription, which is important for maintaining the induced state and requires de novo protein synthesis. Indeed, both phases of COX-2 induction were defective in C/EBP beta-/- macrophages. Moreover, the synthesis of C/EBP delta was increased dramatically by treatment with lipopolysaccharide and, like COX-2 induction, repressed by combined inhibition of the MAPK and of the SAPK2/p38 cascades. Taken together, these data identify CREB, NF-kappa B, and both C/EBP beta and -delta as key factors in coordinately orchestrating transcription from the COX-2 promoter in activated macrophages.

1-Methyl-3-isobutylxanthine↗