Obukhov and Rubinstein reply.
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Journal Article↗
Biomedical subjects
M Rubinstein
Publications and source records attributed to M Rubinstein.
Two antiviral proteins, gp35 and gp22, correspond to beta-1,3-glucanase and an isoform of PR-5.
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Amino Acid Sequence↗
Pharmacokinetics of recombinant interferon alpha-C.
Recombinant interferon alpha-C (rIFN alpha-C, Interpharm), is a new type of alpha-interferon that has a specific activity of 1-2 x 10(9) units/mg protein. The pharmacokinetics of rIFN alpha-C were studied in 11 patients with metastatic renal-cell carcinoma. A total of 10 million units IFN alpha-C were injected intramuscularly and the serum level of IFN was evaluated up to 72 h post-administration. Measurable IFN concentrations appeared in the serum as early as 0.5 h, and levels peaked at 4-6 h (Cmax = 53.2 +/- 4.6 units/ml). Relatively high levels persisted for 24 h and declined thereafter with an apparent half-life of 3-4 h. The mean area under the serum-concentration curve (AUC) was 1,259 +/- 145 units h ml-1, indicating good bioavailability of the preparation from the intramuscular injection.
Aged↗
Cyclosporin A regulates the expression of HLA-DR on human monocytes by two different mechanisms.
Cyclosporin A (CsA), but not its nonimmunosuppressive analog cyclosporin H (CsH), inhibited the expression of HLA-DR in human monocytes. Induction of HLA-DR by interferon (IFN)-gamma in fresh monocytes was also inhibited by CsA and not by CsH. However, when monocytes were pretreated with either CsA or CsH for 16 hr prior to the addition of IFN-gamma, HLA-DR expression was increased, probably because of a cyclosporin-induced increase in the number of IFN-gamma receptors. Down-regulation of the HLA-DR mRNA by CsA was found to be dependent on continuous protein synthesis. IFN-alpha also inhibited the IFN-gamma-induced HLA-DR mRNA expression and showed synergy with CsA at low concentrations but not at high concentrations of the drugs. A common mechanistic element in the pathways of CsA and IFN-alpha is proposed.
Cycloheximide↗
The effect of bilateral sympathectomy on noise induced temporary threshold shift.
The cochlea is innervated by sympathetic nerves originating or passing the superior cervical ganglion. The termination of one type (the vascular independent) is in the habenular region close to the auditory nerve fibers, and the other, the perivascular type, is associated with blood vessels, particularly in the spiral vessel of the tympanic lip. Suggested functions have so far received partial evidence in the literature. Borg (1982) suggested the protective value of sympathectomy of the ear in noise. Our experiments further elaborate this protective value, as it was seen that bilateral cervical sympathectomy diminished the temporary threshold shift in awake, sound exposed GP.
Acoustic Stimulation↗
Sedation effect on temporary threshold shift induced by acoustic overstimulation.
The mechanism by which noise damages the inner ear has not as yet been fully elucidated. Experiments were done to study the influence of the sedation in temporary threshold shift (TS) induced by acoustic overstimulation, as barbiturates were found to improve the brain's tolerance to ischemia. Four groups of guinea pigs (GP) were used. The temporary TS was decreased with the reduction of the temperature in awake, as well as sedated, sound-exposed GP. However, the temporary TS in the sedated, but normothermic GP was as great as in the awake, normothermic group. The high temperature counteracts the protection effect of the sedation in nose-induced hearing loss.
Acoustic Stimulation↗
Resistance to NK cell-mediated cytotoxicity (in K-562 cells) does not correlate with class I MHC antigen levels.
Natural Killer (NK) cells probably function as an early line of defense against virus-infected cells and tumor cells. In all cases, the killing by NK cell-mediated cytotoxicity (NK-CMC) is not MHC-restricted and the factors which determine the sensitivity to NK-CMC have not yet been identified. A positive correlation between resistance to NK-CMC and the level of class I MHC antigen (MHC I) expression on target cells has been reported in many studies, and in some cases a functional linkage between the two has been claimed. Several other studies have shown that there is no such correlation. By employing several experimental systems, we demonstrate here a lack of correlation between the level of MHC I and the sensitivity of K-562 cells to NK-CMC. Transfer of MHC I to MHC I-negative cells via vesicles had no effect on their resistance to NK-CMC. In addition, a decrease in resistance to NK-CMC and increase of MHC I levels was observed following target-cell membrane modulation by both application of cholesterol and hydrostatic pressure. Finally, no correlation between sensitivity to NK-CMC and MHC I expression was found in three sublines of K-562 cells. Since NK-CMC is a multistage process, it is concluded that components other than class I MHC antigens have a more prominent role in modulating the sensitivity of target cells to NK-CMC.
Cell Death↗
Monoclonal antibodies to the soluble human IL-6 receptor: affinity purification, ELISA, and inhibition of ligand binding.
Soluble IL-6 receptor (IL-6-R) purified to homogeneity from normal human urine was used for immunization of mice and rabbits. Spleen cells derived from a mouse showing a high binding titer to IL-6-R in an inverted solid phase radioimmunoassay (IsRIA) and in a Western blotting analysis were fused to mouse myeloma cells. The hybridomas were screened by the IsRIA, and 30 positive clones were isolated and characterized. They were suitable for affinity purification of the IL-6-R and for its detection by Western blot analysis, by ELISA and by sandwich type sRIA. Most of them inhibited the binding of labeled IL-6-R to IL-6 in a solid phase RIA.
Animals↗
The antiproliferative effect of cyclosporine on hematopoietic and lymphoblastoid cell lines--common mechanistic elements with interferon-alpha.
Cyclosporine, but not its nonimmunosuppressive analog cyclosporine H (CsH), caused in a variety of hematopoietic cell types a growth arrest in the G0/G1 phase of the cell cycle. This arrest was associated with a significant reduction in the c-myc mRNA levels, which could be observed already 1 hr following CsA treatment. Similarity between the antiproliferative effects of CsA and IFN-alpha was observed. Thus, the IFN-alpha sensitive human B-lymphoblastoid cell line Daudi was also sensitive to CsA while an IFN-alpha resistant variant of Daudi cells was found to be resistant to CsA as well. Inhibition of protein synthesis with cycloheximide during IFN-alpha or CsA treatment blocked their ability to reduce the expression of c-myc. Depletion of protein kinase C (PKC) activity from cells by pretreatment of Daudi cells with phorbol.12-myristate 13-acetate (PMA) abolished the G0/G1 arrest induced by both CsA and IFN-alpha. Combinations of low concentrations of CsA and IFN-alpha had synergistic effects on cell-cycle distribution and on c-myc mRNA level, suggesting that CsA and IFN-alpha differ in some features of their antiproliferative action. This conclusion was supported by the observation that a CsA-resistant variant of Daudi cells was found to retain its sensitivity to IFN-alpha. In addition, reduction of ornithine decarboxylase mRNA expression was obtained with IFN-alpha but not with CsA. Taken together, our results suggest that CsA and IFN-alpha share some common element(s) in the pathways of their antiproliferative activity. The possible mechanisms of their antigrowth effects and the clinical significance of our findings are discussed.
Blotting, Northern↗
A tyrosine-phosphorylated carboxy-terminal peptide of the fibroblast growth factor receptor (Flg) is a binding site for the SH2 domain of phospholipase C-gamma 1.
Phospholipase C-gamma (PLC-gamma) is a substrate of the fibroblast growth factor receptor (FGFR; encoded by the flg gene) and other receptors with tyrosine kinase activity. It has been demonstrated that the src homology region 2 (SH2 domain) of PLC-gamma and of other signalling molecules such as GTPase-activating protein and phosphatidylinositol 3-kinase-associated p85 direct their binding toward tyrosine-autophosphorylated regions of the epidermal growth factor or platelet-derived growth factor receptor. In this report, we describe the identification of Tyr-766 as an autophosphorylation site of flg-encoded FGFR by direct sequencing of a tyrosine-phosphorylated tryptic peptide isolated from the cytoplasmic domain of FGFR expressed in Escherichia coli. The same phosphopeptide was found in wild-type FGFR phosphorylated either in vitro or in living cells. Like other growth factor receptors, tyrosine-phosphorylated wild-type FGFR or its cytoplasmic domain becomes associated with intact PLC-gamma or with a fusion protein containing the SH2 domain of PLC-gamma. To delineate the site of association, we have examined the capacity of a 28-amino-acid tryptic peptide containing phosphorylated Tyr-766 to bind to various constructs containing SH2 and other domains of PLC-gamma. It is demonstrated that the tyrosine-phosphorylated peptide binds specifically to the SH2 domain but not to the SH3 domain or other regions of PLC-gamma. Hence, Tyr-766 and its flanking sequences represent a major binding site in FGFR for PLC-gamma. Alignment of the amino acid sequences surrounding Tyr-766 with corresponding regions of other FGFRs revealed conserved tyrosine residues in all known members of the FGFR family. We propose that homologous tyrosine-phosphorylated regions in other FGFRs also function as binding sites for PLC-gamma and therefore are involved in coupling to phosphatidylinositol breakdown.
Amino Acid Sequence↗
The prevalence of tardive dyskinesia.
A total of 2250 subjects from psychiatric and geriatric settings was examined for abnormal involuntary movements by the same team of trained raters employing a standard examination technique and rating scale. "Spontaneous" dyskinesia rates were 1.3% among 400 healthy elderly people surveyed at senior citizens centers, 4.8% among medical geriatric inpatients and ranged from 0 to 2% among psychiatric patients never exposed to neuroleptics. For samples of neuroleptic-treated patients, prevalence rates ranged from 13.3% among patients at a voluntary psychiatric hospital to 36.1% among state hospital patients. Logistic regression analyses revealed a large effect of age on tardive dyskinesia prevalence and an interaction of age with sex. Among younger subjects, men had higher rates; among subjects over age 40, rates were higher for women. Edentulousness and presence of other neurological disorders were possible contributors to high rates for the elderly. Even with control for age, sex and duration of neuroleptic exposure, prevalence differed markedly across study site.
Adult↗
A clinical and polysomnographic comparison of neuroleptic-induced akathisia and the idiopathic restless legs syndrome.
Neuroleptic-induced akathisia (NIA) is motor restlessness caused by dopamine receptor blocking antipsychotic agents. Nine patients with NIA and 11 patients with idiopathic restless legs syndrome (RLS) were studied polysomnographically. The sleep disturbances were milder in NIA than idiopathic RLS but increased numbers of awakenings and decreased sleep efficiencies were common to both groups. In addition, RLS patients demonstrated prolonged sleep latencies. Periodic movements in sleep (PMS) were present in only 5 of 9 patients with NIA but in all 11 patients with idiopathic RLS. In no NIA patient did we see the multiple, large amplitude, violent, resting myoclonic jerks of the legs that we saw during wakefulness in some of our more severe cases of idiopathic RLS. NIA patients tended to experience inner restlessness and idiopathic RLS patients tended to experience leg paresthesias as an antecedent to motor restlessness. Idiopathic RLS patients had symptoms that were worse at night and in repose far more frequently than patients with NIA. NIA and idiopathic RLS have similarities and differences. Because both NIA and idiopathic RLS are characterized by motor restlessness and sleep disturbances, the pharmacodynamics of antipsychotic medications may give clues as to both the cause and treatment of idiopathic RLS.
Adult↗
A method for preparing biologically active aqueous cyclosporin A solutions avoiding the use of detergents or organic solvents.
The immunosuppressive agent cyclosporin A (CsA) is highly hydrophobic and is, therefore, being taken for in vitro use directly from ethanolic stock solutions. In the present study it is demonstrated that ethanol itself affects several immunological activities in vitro, thus interfering with the immunosuppressive effects of CsA. As an alternative, it is demonstrated that CsA can be solubilized and retain its activity in aqueous solutions of polyvinyl pyrrolidone (PVP). Unlike ethanol, PVP has no effect on the various immunological activities in vitro and therefore the immunosuppressive effects of CsA can be evaluated without interference.
2',5'-Oligoadenylate Synthetase↗
Topological glass transition in entangled flux state.
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Journal Article↗
Identification and biochemical analysis of novel olfactory-specific cytochrome P-450IIA and UDP-glucuronosyl transferase.
Two major transmembranal polypeptides of bovine olfactory epithelium were identified by SDS electrophoretic analysis of Triton X-114 solubilized membranes. Both polypeptides were present in large amounts in membranes of the olfactory epithelium but were barely detectable in membranes of the nasal respiratory epithelium. Both polypeptides are enriched in the deciliated epithelium as compared with isolated cilia. One of them is a glycoprotein with an apparent molecular mass of 56 kDa (gp56); the other is an unglycosylated protein with an apparent molecular mass of 52 kDa (p52). Sequence analysis of peptides obtained by CNBr cleavage of purified gp56 indicates that it is highly homologous to UDP-glucuronosyl transferase (UDPGT). Parallel analysis shows that p52 is highly homologous to cytochrome P-450 sequences of the IIA subfamily. This protein is assigned the name P-450olf2. Polyclonal antibodies were raised against synthetic peptides corresponding to gp56 and p52 peptide sequences. Immunoblots with these antibodies reveal the following properties of gp56 and p52: (1) they are enriched in the microsomal fraction of the bovine olfactory epithelium; (2) they are possibly specific to the olfactory epithelium, as we could not detect reactivity in microsomes derived from respiratory epithelium or lung, and only a very small amount of basal reactivity was seen with liver microsomes; (3) cross-reacting proteins exist in microsomes derived from the rat olfactory epithelium. These results are consistent with a mechanism whereby the microsomal enzymes are involved in odorant modification and clearance from the nasal tissue.
Amino Acid Sequence↗
Purification of soluble cytokine receptors from normal human urine by ligand-affinity and immunoaffinity chromatography.
Affinity chromatography of crude human urinary proteins on either human recombinant interleukin-6 (rIL-6) or human recombinant interferon-gamma (rIFN-gamma) or anti IFN-gamma receptor (IFN-gamma-R) monoclonal antibodies (McAb) yielded the two respective soluble receptors in significant amounts. A single sequence of 30 amino acid residues was obtained by N-terminal microsequencing of the protein peak purified in tandem by affinity chromatography on an IL-6 column and reversed-phase high-performance liquid chromatography. This sequence was identical with the predicted N-terminal sequence of IL-6-R as previously reported. The purified IL-6-R retained its biological activity. It was used for the preparation of specific anti IL-6-R monoclonal antibodies. Analysis of the eluted proteins from both IFN-gamma and anti IFN-gamma-R columns by inhibition of solid-phase radioimmunoassay, enzyme-linked immunosorbent assay, sodium dodecyl sulphate-polyacrylamide gel electrophoresis and Western blotting proved the existence of soluble IFN-gamma-R in normal urine. This finding together with the already known presence of soluble TNF receptors and a soluble IL-2 receptor found both in plasma and in urine indicates that release of soluble cytokine receptors into body fluids is a general phenomenon which occurs under normal physiological conditions.
Chromatography, Affinity↗
Blood viscosity and sensorineural hearing loss.
Two groups of 33 subjects each, one experimental and one control, matched one-to-one for age and occupation, were chosen from a large number of subjects who were covered by special insurance for annual medical control at our hospital. The periodical checkups included cardiovascular, nervous, and renal systems, as well as vision and hearing. In addition routine blood tests, including whole blood viscosity, were also performed. The experimental group consisted of subjects in whom a bilateral, slight, and unexplained sensorineural loss of hearing was detected in the routine audiological testing, without any known reason. In the control group, the routine hearing tests demonstrated normal hearing. The differences between the two groups were statistically significant in pure-tone threshold level and in speech discrimination score, when the test was performed at a -5dB signal-to-noise ratio. The results of the vestibular tests were normal in both groups. Hematocrit and whole blood viscosity were slightly but significantly higher in the experimental group if compared with the control group. The number of subjects with abnormal whole blood viscosity results was higher in the experimental group. The whole blood viscosity as the etiological factor responsible for the hearing deterioration is described.
Adult↗
Iontophoresis with an adrenergic alpha-blocker in acoustic overstimulation.
To study the influence of sympathetic innervation on the amount of threshold shift (TS) induced by sound overstimulation, iontophoresis with phentolamine, a known adrenergic alpha-blocker, was performed on awake guinea pigs. The sound exposure following this induced a significantly lesser degree of TS when compared with the control group. These findings indicate that iontophoresis may be of great help in transporting specific ionized chemical compounds through the intact cochlear walls in a completely non-invasive manner for studying cochlear physiology.
Acoustic Stimulation↗