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Biomedical subjects

D Cohen

Publications and source records attributed to D Cohen.

At least 217 records · Page 12Linked to original sources
PubMed1998

Relation of visual perception and visual-motor integration for clumsy children.

The purpose of this study was to examine the relationship between visual perception and visual-motor integration in 30 normal children compared to 30 clumsy children. Difficulty in visual perception, as assessed by the Test of Visual-Perceptual Skills, accounts for about half the variance in the clumsy children's performance in visual-motor integration, as assessed by the Developmental Test of Visual Motor Integration. In contrast, the correlation between scores on these tests for normal control children was low and not significant. These results suggest that visual perception and visual-motor integration may be separate functions in normally developing children. When considering clumsy children, however, these functions cannot be considered as two independent skills.

Child↗
PubMed1998

An objective measure of seat comfort.

Uncomfortable aircrew seating is more than just a nuisance, it has the potential to produce a cumulative trauma which can significantly affect attention, information processing, and task performance to the extent of interfering with mission completion or contributing to mishaps. Yet, for decades uncomfortable seating has endured as an aircrew complaint with little progress made toward resolving it. Aircraft design techniques have steadily progressed, but the method for ascertaining seating pressure issues has remained, unfortunately, the same: simply ask aircrew where it hurts and hope some cushion changes work. Currently, there exist sensor technologies which potentially can economically and effectively address this problem by reducing the comfort analysis to the examination of an objective, quantitative pressure map. This technical note discusses the brief history of seat pressure measurement research, enumerates some of the technologies that are available that can be applied to the problem, and finally, describes a seated pressure measurement demonstration which shows the power of the approach for maximizing comfort.

Aerospace Medicine↗
PubMed1998

Prosthodontic and surgical management of a patient with an osteoma of the temporomandibular joint.

Osteomas of the temporomandibular joint are rare. This article presents a case report delineating treatment of a partially edentulous patient using a team approach for an osteoma originating from the anterolateral aspect of the glenoid. The tumor was diagnosed with the aid of a panoramic radiograph and a computerized axial tomograph. Interim prostheses with anterior teeth and posterior teeth with nonanatomic occlusal surfaces were fabricated before surgery. After surgical excision of the osteoma, the interim prostheses were periodically adjusted as the mandibular condyle gradually shifted into the space that was previously occupied by the tumor. Final removable prostheses were fabricated after the condyle had stopped shifting.

Aged↗
PubMed1998

[Vaginal myomectomy].

The authors present a retrospective study of 26 patients who have benefited from vaginal myomectomy after culdotomy in the Conception hospital in Marseille between 1992 and 1997. The myomectomy whom technic is described, was performed unically through the vagina or laparoscopically assisted. The mean operating time was 94 mn. The myoma mean weight was 184.3 g. Three patients experienced an abdominal surgery, twice because of a vaginal inaccessness. The immediate and mean-term post-operative period was uncomplicated in most cases. For screened patients, vaginal myomectomy appears as an interesting alternative to abdominal or laparoscopic surgery.

Adult↗
PubMed1998

The multidrug resistance modulator valspodar (PSC 833) is metabolized by human cytochrome P450 3A. Implications for drug-drug interactions and pharmacological activity of the main metabolite.

The metabolism of valspodar (PSC 833; PSC), which is developed as a multidrug resistance-reversing agent, was investigated to assess the potential for drug-drug interactions and the pharmacological activity of major metabolites. The primary metabolites of PSC produced by human liver microsomes were monohydroxylated, as revealed by LC/MS. The major site of hydroxylation was at amino acid 9, resulting in M9, as determined by cochromatography with synthetic M9. Dihydroxylated and N-demethylated metabolites were also detected. PSC metabolism in two human livers exhibited KM values of 1.3-2.8 microM. The intrinsic clearance was 9-36 ml/min/kg of body weight. PSC biotransformation was cytochrome P450 (CYP or P450) 3A dependent, based on chemical inhibition and on metabolism by Chinese hamster ovary cells expressing CYP3A. Ketoconazole was a competitive inhibitor (Ki = 0.01-0.04 microM). The inhibition by 27 compounds, including four antineoplastic agents, corresponded to the inhibitory potentials of these compounds toward CYP3A. For vinblastine, paclitaxel, doxorubicin, and etoposide, the IC50 values were 5, 12, 20, and 150 microM, respectively. M9 was also an inhibitor, with a lower apparent affinity for CYP3A (IC50 = 21 microM), compared with that of PSC. M9 was also less active as a multidrug resistance-reversing agent. M9 demonstrated low potency in sensitizing resistant cells to paclitaxel and was a poor inhibitor of rhodamine-123 efflux from paclitaxel-resistant cells. In addition, compared with PSC, a higher concentration of M9 was needed to compete with the photoaffinity labeling of P-glycoprotein. Conversely, PSC inhibited only reactions catalyzed by CYP3A, including cyclosporine A metabolism (IC50 = 6.5 microM) and p-hydroxyphenyl-C3'-paclitaxel formation (Ki = 1.2 microM). Thus, PSC behaves in a manner very similar to that of other cyclosporines, and a comparable drug-drug interaction profile is expected.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1998

Effects of fish oil on cytokines and immune functions of mice with murine AIDS.

The effects of fish oil, which is rich in n-3 fatty acids, on cytokine levels in a murine model of acquired immune deficiency syndrome (AIDS) were studied. Thirty-two C57BL/6 female mice were divided into two dietary groups and fed either a corn oil diet or a fish oil diet. After 4 weeks, each diet group was further divided into two subgroups, and mice in one subgroup were injected i.p. with LP-BM5 murine retrovirus (MAIDS) stock. After 4 weeks, all mice were killed, blood samples were collected, and the spleens and the livers were excised. Splenocytes were isolated immediately and cultured in RPMI-1640 medium and stimulated by either lipopolysaccharide (LPS) or Concanavalin A (ConA) for 24 h. The supernatant was collected for cytokine assays. The results showed that MAIDS infection increased the levels of tumor necrosis factor-alpha (TNF-alpha) and interleukin-1-beta (IL-1beta), while fish oil partially prevented this elevation. MAIDS infection depressed interleukin-2 (IL-2) and interferon-gamma (IFNgamma), while fish oil partially prevented the depression of IL-2. In addition, MAIDS infection depressed LPS- and ConA-stimulated cell proliferation, while fish oil partially prevented the depression. The results suggest that fish oil may slow down the progression of murine AIDS by modulating levels of cytokines including TNF-alpha, IL-1beta, and IL-2.

Animals↗
PubMed1998

Plasma concentration, kinetic constants, and gene polymorphism of angiotensin I-converting enzyme in centenarians.

We have determined serum activity and kinetic constants of angiotensin I-converting enzyme (ACE), parallel to an insertion/deletion (I/D) polymorphism in its gene, in French centenarians and controls 20-70 years of age because this enzyme could have an impact on cardiovascular risk, and thus on longevity. Both the ACE D allele and ACE D/D genotype were more frequent in centenarians in comparison with controls, without sex-related differences nor significant correlation with a cardiovascular pathology. In centenarians, I/D polymorphism was correlated with circulating ACE activity (D/D genotype, 89.0 +/- 36.8 U/L; I/D genotype, 63.5 +/- 26.0 U/L; and I/I genotype, 55.1 +/- 39.4 U/L). The Michaelis constants for two substrates were identical whatever the genotype and were not different between centenarians and controls, i.e., 0.30 +/- 0.03 mmol/L for furylacryloyl-phenylalanyl-glycyl-glycine and 1.35 +/- 0.05 mmol/L for hippuryl-histidyl-leucine; for the latter, the optimal pH and activating concentration of chloride did not depend on I/D polymorphism. The maximal velocities with both substrates reflected the distribution of serum ACE activity as a function of the genotypes, in centenarians and in controls. In conclusion, plasma ACE activity is subject to a similar genotypic influence in centenarians as in adults 20-70 years of age; however, ACE itself appears to be functionally similar for each genotype. Furthermore, the D allele as well as the higher serum ACE activities associated with the D/D genotype cannot discriminate individuals at high risk for cardiovascular diseases, major causes of mortality before the age of 100 years.

Adult↗
PubMed1998

Diagnostic accuracy of transvaginal ultrasound in detecting free pelvic fluid.

OBJECTIVE: To evaluate the diagnostic accuracy of transvaginal ultrasonography in detecting and measuring free pelvic fluid. STUDY DESIGN: Eighty-two patients undergoing diagnostic or therapeutic laparoscopy at a tertiary care center were prospectively assessed before surgery by transvaginal ultrasound. Free pelvic fluid was measured in two ultrasonographic planes. These measurements were compared to the volume of fluid aspirated during laparoscopy. RESULTS: The mean volumes reported for transvaginal ultrasound were significantly lower than those observed at laparoscopy (mean milliliters +/- SEM, 2.54 +/- 0.5 versus 9.42 +/- 1.3, P < .001). The smallest volume of free pelvic fluid that was consistently detected by ultrasound was 8 mL. Whenever no fluid or < 1 mL was detected by transvaginal ultrasound, a small volume of fluid was found at laparoscopy (mean milliliters +/- SEM, 1.6 +/- 0.47). The sensitivity of transvaginal ultrasound was 83% and specificity was 69%. CONCLUSION: Transvaginal ultrasound is a sensitive method of detecting the presence of > 8 mL of free pelvic fluid and therefore is an important diagnostic tool in the assessment of pelvic pathology associated with increased peritoneal fluid.

Adult↗
PubMed1997

Myosin II is involved in the production of constitutive transport vesicles from the TGN.

The participation of nonmuscle myosins in the transport of organelles and vesicular carriers along actin filaments has been documented. In contrast, there is no evidence for the involvement of myosins in the production of vesicles involved in membrane traffic. Here we show that the putative TGN coat protein p200 (Narula, N., I. McMorrow, G. Plopper, J. Doherty, K.S. Matlin, B. Burke, and J.L. Stow. 1992. J. Cell Biol. 114: 1113-1124) is myosin II. The recruitment of myosin II to Golgi membranes is dependent on actin and is regulated by G proteins. Using an assay that studies the release of transport vesicles from the TGN in vitro, we provide functional evidence that p200/myosin is involved in the assembly of basolateral transport vesicles carrying vesicular stomatitis virus G protein (VSVG) from the TGN of polarized MDCK cells. The 50% reduced efficiency in VSVG vesicle release from the TGN in vitro after depletion of p200/myosin II could be reestablished to control levels by the addition of purified nonmuscle myosin II. Several inhibitors of the actin-stimulated ATPase activity of myosin specifically inhibited the release of VSVG-containing vesicles from the TGN.

Actins↗
PubMed1997

Compliance with voluntary prenatal HIV testing in a large health maintenance organization (HMO).

Results of a recent national clinical trial show that maternal-to-fetal transfer of HIV can be decreased threefold by prenatal, intrapartum, and neonatal treatment. The question is whether to make prenatal HIV testing compulsory or to encourage voluntary testing. Kaiser Permanente Northern California (KPNC), which has 2.5 million members, is part of a large health maintenance organization (HMO). In 1994, KPNC cared for 32,700 prenatal patients; 16,500 (50%) agreed to voluntary HIV testing. Compliance with testing ranged from 0% to 92% among the 31 KPNC locations. A study done by telephone survey identified three main factors favoring success of voluntary HIV screening: the ease and accessibility of HIV testing, a designated educator, and the presence of a registered nurse on the counseling team. In 1995, following feedback to the 31 facilities of the 1994 results, compliance rose to 19,800 of 31,300 prenatal patients (63%). KPNC, by encouraging counseled voluntary screening and following known positive cases, hopes to identify, track, and offer treatment options to all HIV-positive prenatal patients.

Female↗
PubMed1997

Cyclosporine-associated end-stage nephropathy after cardiac transplantation: incidence and progression.

BACKGROUND: The salutary immunosuppressive effects of cyclosporine in extending cardiac allograft survival may be curtailed by its nephrotoxic effects. We reviewed our first 9 years of experience with cyclosporine after cardiac transplantation, to evaluate the incidence and progression of cyclosporine-associated end-stage renal failure necessitating chronic hemodialysis. METHODS: Retrospective computer-based file review and personal interview when possible. RESULTS: The population at risk was comprised of all adult cardiac recipients surviving at least 3 years (n=293). Of these, 19 (6.5%) developed end-stage renal failure requiring chronic hemodialysis. There were 17 men and 2 women (mean age of 45 +/- 11 years). The mean creatinine clearance for the study group decreased by 38% (P<0.001 vs. before transplant) by 6 months after transplantation and by 48% by 3 years postoperatively (P<0.001 vs. before transplant). The mean serum creatinine rose by 80% (P< 0.001 vs. before transplant) by 6 months after transplantation and by 125% by 3 years postoperatively (P<0.001 vs. before transplant). Time elapsed from transplantation to hemodialysis ranged from 3.7 to 9.5 years (mean 6.4 +/- 2). Actuarial 1- year survival after onset of hemodialysis was 75%. CONCLUSIONS: Although cyclosporine remains the central immunosuppressive agent for cardiac allograft recipients, its use leads to a greater than one-third decrease in creatinine clearance by 6 months after transplantation and progression to end-stage renal failure, requiring hemodialysis in 6.5% of cardiac transplant recipients. Moreover, these patients are at increased risk of death compared with other cardiac allograft recipients. This data warrants the search of alternative or adjunctive agents that would allow decreased dosing or reduced nephrotoxicity of cyclosporine, while maintaining equivalent survival.

Adult↗
PubMed1997

Double-blind vaccine-controlled randomised efficacy trial of an investigational Shigella sonnei conjugate vaccine in young adults.

BACKGROUND: The aim of this double-blind randomised vaccine-controlled trial was to assess the efficacy of a conjugate vaccine composed of Shigella sonnei O-specific polysaccharide bound to Pseudomonas aeruginosa recombinant exoprotein A (S sonnei-rEPA) and of an oral, live-attenuated Escherichia coli/S flexneri 2a (EcSf2a-2) hybrid vaccine among military recruits in Israel at high risk of exposure to Shigella spp. We report here our preliminary findings on the efficacy of S sonnei-rEPA; we have not documented sufficient cases to assess the efficacy of EcSf2a-2. METHODS: Between April, 1993, and August, 1994, male Israeli Military recruits aged 18-22 years were asked to take part in our study. We enrolled 1446 soldiers from seven separate field sites (groups A-G). Soldiers were randomly allocated one injection of S sonnei-rEPA and four doses of oral placebo (n = 576), four oral doses of EcSf2a-2 and one injection of saline placebo (n = 580), or one injection of meningococcal tetravalent control vaccine and four doses of oral placebo (n = 290). Because there were no cases of S flexneri 2a, the EcSf2a-2 and meningococcal vaccines were the control group. We defined S sonnei shigellosis as diarrhoea with a positive faecal culture for S sonnei. Each group of soldiers was followed up for 2.5-7.0 months. The primary endpoint was protective efficacy of S sonnei-rEPA against S sonnei shigellosis. FINDINGS: Cases of culture-proven S sonnei shigellosis occurred in four groups of soldiers (groups A-D), which comprised 787 volunteers (312 received S sonnei-rEPA, 316 received EcSf2a-2, and 159 received meningococcal control vaccine). In groups A-C, cases of shigellosis occurred 70-155 days after vaccination, whereas in group D cases occurred after 1-17 days. In groups A-C, the attack rate of shigellosis was 2.2% in recipients of S sonnei-rEPA compared with 8.6% in controls (protective efficacy 74% [95% CI 28-100], p = 0.006). S sonnei-rEPA also showed significant protection against shigellosis in group D (43% [4-82], p = 0.039). Prevaccination and postvaccination ELISA measurements of antibody to S sonnei lipopolysaccharide among recipients of S sonnei-rEPA showed that the vaccinees who developed S sonnei shigellosis had significantly lower serum IgG and IgA responses to the homologous lipopolysaccharide than those who did not (p = < 0.05). INTERPRETATION: One injection of S sonnei-rEPA confers type-specific protection against S sonnei shigellosis. The high antibody concentration induced by the conjugate vaccine in volunteers who did not develop shigellosis suggests that there is an association between serum antibody titre and protection.

Adolescent↗
PubMed1997

Functional modulation of ATPase of P-glycoprotein by C219, a monoclonal antibody against P-glycoprotein.

P-glycoprotein functions as an ATP-driven efflux pump for antitumor agents. C219 is a monoclonal antibody which recognizes regions near both ATP binding domains in each half of P-glycoprotein. In this study, we have demonstrated that C219 inhibits the ATPase activity of P-glycoprotein based on the following findings: 1) the inhibition of total ATPase activity by C219 was selective to P-glycoprotein-positive membranes; 2) the C219-sensitive fraction of ATPase correlated the expression of P-glycoprotein; and 3) modulators of P-glycoprotein ATPase, verapamil and cyclosporin A, affected the C219-sensitive fraction of ATPase. The photolabeling of P-glycoprotein with 8-azido-[alpha-32P]ATP was inhibited by C219, suggesting that the inhibition of ATP binding by C219 reduced the activity. Since C219 interacts with P-glycoprotein ATPase, C219 might become a useful tool for studying the role of P-glycoprotein ATPase.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1997

The indications, rationale, and results of neoadjuvant androgen deprivation in the treatment of prostatic cancer: Memorial Sloan-Kettering Cancer Center results.

OBJECTIVES: The use of neoadjuvant chemotherapy prior to definitive surgery has been firmly established in other areas of oncology, most notably in the treatment to testis and Wilm's tumors. The use of neoadjuvant androgen deprivation therapy (ADT) in conjunction with radical prostatectomy remains a source of controversy. We have conducted phase II and phase III studies to assess the effects of 3 months of preoperative ADT (goserelin and flutamide) on the pathologic staging and postsurgery prostate-specific antigen (PSA) relapse rate. We also reviewed the data confirming the understaging of clinically localized prostatic cancer and the experimental data providing the conceptual support for ADT. METHODS: We report the results of 141 patients, Stage T0-T0, in a Phase II study with concurrent, nonrandomized controls (N = 72) versus a treatment arm (N = 69) of men receiving 3 months of ADT with 3.6 mg goserelin for 28 days and 750 mg flutamide daily. We also report the interim results in 114 men participating in a prospective, randomized study of ADT versus surgery alone. RESULTS: The 69 patients who received 3 months of goserelin and flutamide followed by radical prostatectomy had a pathologic organ-confined cancer rate of 74%, versus 48% in the control group who received no ADT prior to surgery. The margin-positive rate was 10% in the ADT group versus 33% in the control group. In an interim analysis of 114 patients (59 ADT, 55 control), the organ-confined and margin-positive rates were 73% and 17% in the ADT group versus 56% and 36% in the control arm, respectively. The PSA disease-free rate at a mean follow-up of 28.6 months (range 6.2 to 49.5 months) was 89% in the ADT-treated patients (N = 98) and 84% in the control patients (N = 96). There was no statistical difference demonstrated between the arms with respect to biochemical failure. CONCLUSIONS: While the pathologic staging of tumors following ADT treatment was improved compared with surgical controls, to date the PSA disease-free survival rates are similar. Patients with residual extracapsular (P3) disease after ADT manifest an increased PSA failure rate compared with those with P3 tumors treated by surgery alone. This suggests that ADT may identify a subset of patients with aggressive tumors that may be candidates for additional therapeutic interventions even before PSA failure occurs.

Aged↗