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S Solomon

Publications and source records attributed to S Solomon.

At least 37 records · Page 2Linked to original sources
PubMed1996

The isolation and characterization of a novel corticostatin/defensin-like peptide from the kidney.

We report the isolation and characterization of RK-1, a novel peptide found in the kidney. RK-1 is related to the corticostatin/defensins and has the sequence MPC-SCKKYCDPWEVIDGSCGLFNSKYCCREK but differs from the very cationic corticostatins/defensins in having only one arginine and a calculated charge at pH 7 of +1. Like some myeloid corticostatin/defensins RK-1 inhibits the growth of Escherichia coli. Since corticostatin/defensins effect ion flux in responsive epithelia we used volume changes in villus enterocytes as a model system to study the effects of RK-1 on ion channels in epithelial cells. At concentrations > or = 10(-9) M RK-1 decreased enterocyte volume in a dose-dependent manner through a pathway that requires extracellular calcium and is inhibited by niguldipine, a dihydropyridine-sensitive "L"-type Ca(2+)-channel blocker. In other assay systems for corticostatin-defensins, such as the inhibition of adrenocorticotropin-stimulated steroidogenesis, or cell lysis, RK-1 was inactive or only weakly active. These results demonstrate the existence of a novel system of biologically active peptides in the kidney represented by RK-1 which is antimicrobial and can activate epithelial ion channels in vitro.

Adrenal Cortex Hormones↗
PubMed1996

Corticostatins/defensins inhibit in vitro NK activity and cytokine production by human peripheral blood mononuclear cells.

Corticostatins/defensins are a family of cationic peptides recently isolated from phagocytotic cells of the myeloid lineage. Natural killer (NK) cells are spontaneously cytotoxic large granular lymphocytes that are involved in immunosurveillance against cancer and infections. Their activity is modulated by hormones of the hypothalamic-pituitary-adrenal axis. We wished to determine whether two human corticostatins/defensins, HP-1 and HP-4, are able to change in vitro the spontaneous NK activity of human peripheral blood mononuclear cells (PBMC) and the responses either to the stimulatory cytokines immune interferon (IFN-gamma) or interleukin 2 (IL-2) and to the inhibitory hormone cortisol. NK cell activity was measured in a 4-h direct cytotoxicity assay with K562 cells as a target. HP-1 and HP-4 (10 (-8) -10 (-9) M) significantly inhibited the spontaneous and cytokine-inducible NK activity, and increased the cortisol-dependent inhibition. Radioimmunoassay of HPLC purified fractions obtained from sonicated NK cells showed HP-1 in the two cell preparations examined. We also evaluated the effects of HP-1 and HP-4 (10 (-8) M -10(-9) M) upo IFN-gamma and interleukin 6 (IL-6) production by PBMC stimulated with phytohemagglutinin (PHA) or concanavalin A (ConA). IFN-gamma was titrated with the biological assay using WISH cells as indicators and vescicular stomatitis virus (VSV) as the challenge virus. IL-6 was measured using an enzyme amplified sensitivity immunoassay. Both HP-1 and HP-4 significantly reduced cytokine production. Our data indicate that corticostatins/defensins are novel modulators of lymphocyte functions in vitro. Their immunodepressing properties could add complexity and plasticity to hypothalamic-pituitary-adrenal-cytokine circuits in vivo.

Adrenal Glands↗
PubMed1996

Improving hospital-acquired infection rates: the CDC experience.

BACKGROUND: The National Nosocomial Infections Surveillance (NNIS) System, begun in 1970 by the Centers for Disease Control to collect data on hospital-acquired infections, is one of the oldest continuously operating clinical performance indicator systems in the United States. Growth of the system, from 19 to 230 hospitals, has been accompanied by developments such as the evolution from hospitalwide to targeted surveillance, improved data processing and telecommunications for data collection and reporting, and risk adjustment. ELEMENTS OF A SUCCESSFUL SYSTEM: The NNIS System provides specific, standardized methods for data collection and uses device-associated, device-day rates to risk adjust the data and make it meaningful for interhospital comparison. The system has been used as a tool for improving quality of care through prevention of nosocomial infections. For example, an 800-bed teaching hospital's rate of ventilator-associated nosocomial pneumonia in the surgical intensive care unit-49.5 infections per 1,000 ventilator days-was in excess of the 90th percentile. Improvements in care, including changing tubing and cascades every 48 hours and Ambu bags every 24 hours, as well as increased clinical evaluation of patients, was followed 12 months later by a decrease to 25.8 infections, well below the 90th percentile. INFORMATION DISSEMINATION: Since 1992, staff from NNIS hospitals have met in a biennial conference to learn about advances in nosocomial infection surveillance and to share information with one another on infection control and quality improvement programs. CONCLUSIONS: The NNIS experience can be used as a source of guidance for assessing the effectiveness and utility of other indicator systems.

Adult↗
PubMed1996

Soluble matrix of hen's eggshell extracts changes in vitro the rate of calcium carbonate precipitation and crystal morphology.

1. Extra and intramineral eggshell matrix proteins were solubilised before and after demineralisation by sequential extractions using guanidine hydrochloride and EDTA. 2. The intramineral electrophoretic profile of SDS-PAGE showed the presence of 80, 66, 43, 36 and 15 kDa bands with a predominance of a 17 kDa band. In the extramineral part, the major protein was the 15 kDa band. 3. The introduction of intramineral extract to a metastable solution of calcium carbonate delayed the rate of crystal growth. The delay in the rate of precipitation was elicited by a single fraction (MW 50-80 kDa), isolated by gel filtration chromatography, of eggshell extracts. Extramineral extracts had no effect. 4. Addition in vitro of intramineral eggshell extracts modified the morphology of calcite; the crystals aggregated and showed irregular surfaces. 5. These observations suggest that constituents of the eggshell matrix are involved in the control of calcite growth and crytallographic structure of the hen's eggshell.

Animals↗
PubMed1996

Long-term follow-up of joint stabilization procedures in the treatment of fixed deformities of feet in leprosy.

This retrospective study of 52 patients, who underwent joint stabilization procedures for static deformities of the feet in leprosy between 1971 and 1985, was undertaken to asses the long-term results of joint stabilization of feet for fixed deformities in leprosy. The main purpose of joint stabilization is to make the feet plantigrade for weight bearing and to make the wearing of footwear possible. Deformities corrected include varus, equinus and equinovarus. Chronic ulceration occurs repeatedly if these deformities are not corrected and leads to inevitable bone destruction and eventual amputation.

Adult↗
PubMed1996

Comparative trial of steroids and surgical intervention in the management of ulnar neuritis.

Fifty-seven ulnar nerves in 39 patients with early neuritis were studied to assess the benefits offered by medial epicondylectomy and external decompression in addition to steroid therapy. The patients were randomly allocated to the surgical or medical group. In those cases where there was bilateral involvement, surgery was carried out on only one side. All cases were assessed prior to treatment and after the first and second years following treatment. The improvement in motor and sensory functions attained at the end of the first year was sustained into the second year. The improvement sustained in both groups was similar even in the second year, and medial epicondylectomy with external decompression seems to have no added benefit as compared to steroid therapy alone in the early treatment of ulnar neuritis. Early diagnosis and treatment, especially in borderline lepromatous cases, seem to offer some hope of nerve function recovery.

Bone and Bones↗
PubMed1995

Age at onset of geriatric depression and sensorineural hearing deficits.

Comorbidity of sensorineural hearing deficits and both depressive states and dementia in late life provided the rationale for this investigation. Cognitively intact geriatric major depressives (n = 43) were assessed for depressive symptoms, cognitive performance, and delusions while symptomatic, and following treatment, when audiometry was performed. Late-onset depressed patients (LOD) had more hearing deficits compared to early-onset depressives (EOD). Age at onset of depression was found to have a significant effect on Pure-Tone Thresholds for 0.5-4.0 kHz and on Word Recognition in Noise in the better ear (0.001 < p < 0.031; ANCOVA). Criteria for neural deficit were met more frequently in LODs compared to EODs, although this was attributable to the older age of LOD. Additional investigations can contribute to our understanding of the relationship between forms of hearing loss and both the course of geriatric depression and its relationship to dementia.

Age of Onset↗
PubMed1995

Migraine prophylaxis with divalproex.

OBJECTIVE: To compare the effectiveness and safety of divalproex sodium (Depakote) and placebo in the prophylaxis of migraine headache. DESIGN: Multicenter, double-blind, randomized, placebo-controlled investigation, having a 4-week, single-blind placebo baseline phase and a 12-week treatment phase (4-week dose adjustment, 8-week maintenance). SETTING: Eight headache/neurology clinics throughout the United States. PATIENTS: One hundred seven patients randomized to divalproex or placebo (2:1 ratio): 70 receiving divalproex and 37 receiving placebo. INTERVENTION: Divalproex and placebo dosages titrated in blinded fashion during dose adjustment period to achieve actual/sham trough valproate sodium concentrations of approximately 70 to 120 mg/L. MEASUREMENTS AND MAIN RESULTS: During the treatment phase, the mean migraine headache frequency per 4 weeks was 3.5 in the divalproex group and 5.7 in the placebo group (p < or = .001), compared with 6.0 and 6.4, respectively, during the baseline phase. Forty-eight percent of divalproex-treated patients and 14% of placebo-treated patients showed a 50% or greater reduction in migraine headache frequency from the baseline phase (P < .001). Among those with migraine headaches, divalproex-treated patients reported significantly less functional restriction than placebo-treated patients and used significantly less symptomatic medication per episode. No significant treatment group differences were observed in average peak severity or duration of individual migraine headaches. Treatment was stopped in 13% of divalproex-treated patients and 5% of placebo-treated patients because of intolerance (P, not significant). CONCLUSIONS: Divalproex is an effective prophylactic drug for patients with migraine headaches and is generally well tolerated.

Adolescent↗
PubMed1995

Restricted ability to recover three-dimensional global motion from one-dimensional motion signals: psychophysical observations.

We tested human ability to recover the 3D structure and motion information from time-varying images where only 1D motion cues were available. Under these conditions, observers exhibit poor performance in discriminating between two perpendicular axes of rotation, or discriminating between rigid and non-rigid 3D motion. This behavior of the visual system is to be contrasted with the good depth from motion performance exhibited when 2D motion cues are given in the image, as was found previously in numerous studies, and also in the work presented here. In a related paper, we suggest a theoretical framework in which to understand this differential performance on the basis of the two types of motion cues (1D vs 2D). Our findings are consistent with those of previous studies of frontoparallel motion, where it was shown that in many cases, the 1D cues alone were not integrated by the visual system into the correct global motion percept. This accumulating evidence suggests that oriented (1D) motion detectors alone cannot account for observed human performance of global motion perception, and that the role of units such as point or endpoint detectors should be studied further.

Cues↗
PubMed1995

Restricted ability to recover three-dimensional global motion from one-dimensional local signals: theoretical observations.

Recovering 3D information from a 2D time-varying image is a vital task which human observers face daily. Numerous models exist which compute global 3D structure and motion on the basis of 2D local motion measurements of point-like elements. On the other hand, both experimental and computational research of early visual motion mechanisms emphasize the role of oriented (1D) detectors. Therefore, it is important to find out whether indeed 1D motion signals can serve as primary cues for 3D global motion computation. We have addressed this question by combining mathematical results and perceptual observations. We show that given the 2D-projected 1D instantaneous velocity field, it is mathematically impossible to discriminate rigid rotations from non-rigid transformations and/or to recover the rotation parameters. We relate this fact to existing results in cases where localized (point-like) cues are present, and to our own experiments on human performance in global motion perception when only 1D cues are given. Taken together, the data suggest a necessary role for localized information in early motion mechanisms and call for further physiological and psychophysical research in that direction.

Cues↗
PubMed1995

Rat corticostatin R4: synthesis, disulfide bridge assignment, and in vivo activity.

We have synthesized significant amounts of the most potent member of the rat corticostatins that inhibits ACTH-induced corticosteroid and compared its structure to that of the natural hormone. The cystine bridging arrangement that corresponds to that reported for a human defensin (3-31, 5-20, 10-30) was determined. The in vitro corticostatic activity of the synthetic rat corticostatin R4 paralleled that of the natural R4. Biological studies in vivo showed that doses of 8 or 12 mg corticostatin/kg effectively interfered with corticosterone release in stressed rats. We conclude that in the assays that were used, the biological activity of the synthetic and natural molecules was identical. The availability of significant amounts of synthetic material will make possible studies investigating the physiological role played by corticostatins in modulating the activity of the hypothalamic-pituitary-adrenal axis.

Adrenal Glands↗