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Biomedical subjects

M Rubinstein

Publications and source records attributed to M Rubinstein.

At least 181 records · Page 10Linked to original sources
PubMed1987

The human interferon-gamma receptor. Purification, characterization, and preparation of antibodies.

The receptor for human interferon-gamma (IFN-gamma) was purified from foreskin fibroblasts. Triton X-100 extracts obtained from either intact cells or membrane preparations were passed through an immobilized interferon-gamma column. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) of eluted fractions revealed a major band of Mr = 95,000 and minor bands of Mr = 80,000 and 60,000. Further purification was obtained by steric exclusion and by lectin chromatography. The purified receptor retained the ability to bind 125I-IFN-gamma with a Kd of 2.2 X 10(-10) M, a value close to that obtained with intact fibroblasts (5 X 10(-10) M). A complex of Mr = 105,000-125,000 was visualized by immunoprecipitation of 125I-IFN-gamma cross-linked to the purified receptor followed by SDS-PAGE and autoradiography. A similar complex was obtained when 125I-IFN-gamma was cross-linked to intact cells. Immunization of mice with the excised SDS-PAGE band of Mr = 95,000 elicited antibodies that blocked the antiviral activity of IFN-gamma and immunoprecipitated the cross-linked complex of 125I-IFN-gamma and its receptor.

Antibodies↗
PubMed1987

Surgical approach to the superior vestibular nerve in guinea pigs.

The superior vestibular nerve carries homo- and contra-lateral efferent fibers to the cochlea. The subarcuate fossa, a tube-like structure in the temporal bone of the guinea pig, can be used to reach the superior vestibular nerve at the level of the internal acoustic meatus. Normally, this structure accommodates the dorsal and ventral floccular extension of the cerebellum. This technique has several advantages. Firstly, a reduced cranial opening is necessary; secondly, less cerebellar tissue is sacrificed. Then there is the relative insulation of the operative field, and finally, it presents a straight guide to the internal auditory meatus and vestibular nerve.

Animals↗
PubMed1987

Multiple interferon subtypes: the phenomenon and its relevance.

Over the last 10 years the structure of various human interferon-alpha (IFN-alpha) and interferon-gamma (IFN-gamma) subtypes was elucidated by combining protein chemistry and molecular biology. In this article some key studies related to the interferon structure are reviewed. The significance of the multiplicity of IFN-alpha and IFN-gamma subtypes is discussed in view of some current results.

Humans↗
PubMed1987

Cochlear action potentials threshold and systemic arterial pO2.

A progressive decrease in arterial pO2 was induced in Hartley guinea pigs (GP) by having them rebreathe the air entrapped in a closed circuit from which the CO2 was continuously absorbed. Following this slow-developing hypoxemia, a sequence of events concerning the ear could be observed. Firstly, a fluctuation in cochlear action potentials (CAP) was noted. This appeared only at stimulus intensities near the threshold and was not evident at higher intensities. At a mean arterial pO2 level of 30 mm Hg, this phenomenon was observed in 60% of the GP. At a mean pO2 of 24.66 mm Hg, a shift in threshold occurred in all GP. Finally, when the blood pO2 reached an average of 14.92 mm Hg, no CAP response could be elicited, even at click intensity of 120 dB SPL. The 30 mm Hg oxygen concentration in the arterial blood was considered as a "critical level" at which the cochlear function starts to deteriorate in guinea pigs.

Animals↗
PubMed1986

Priming of leukocytes selectively increases the level of some interferon-alpha subtypes and not others.

The effect of pretreatment with interferon (IFN) ('priming') on the production of individual IFN subtypes was studied in subpopulations of human peripheral blood mononuclear cells and in the myeloid cell line KG-1. It was found that priming had a selective enhancing effect on the production of certain IFN-alpha subtypes (IFN-alpha 20K and IFN-alpha 21K) and not on others. KG-1 cells produce both IFN-alpha and -beta; however, only the production of IFN-alpha was enhanced by priming with either IFN-alpha, beta or gamma.

Animals↗
PubMed1986

Seasonal variation of platelet serotonin uptake and 3H-imipramine binding in normal and depressed subjects.

Density of 3H-imipramine binding sites and serotonin (5-HT) uptake in blood platelets were repeatedly recorded in normal controls (n = 9) and depressed patients (n = 7 for the imipramine binding assay and n = 4 for the serotonin uptake) over a 1-year period. The study demonstrated a striking seasonal variation of both parameters in both groups, with lower values in winter and spring than in summer and fall. No difference in the density of 3H-imipramine binding sites was found between the two populations throughout the year, but serotonin uptake was significantly decreased in depressed patients in May and September. These results underscore the importance of studying controls and patients at the same time of the year.

Adult↗
PubMed1986

Human monocytes tumoricidal activity: the role of interferon-gamma and bacterial lipopolysaccharide in its stimulation, preservation and decay.

The effect of interferon-gamma (IFN-gamma) and bacterial lipopolysaccharide (LPS) on the cytotoxic activity of cultured monocytes was studied in a 6-h51Cr release assay with Actinomycin-D-treated tumor cells as targets. In this system, the lysis of target cells is mediated by a soluble factor (CF) which is similar or identical to human tumor necrosis factor (TNF). The spontaneous cytotoxic activity of freshly isolated monocytes declined after their maturation to macrophages during in vitro culturing. The decrease in the ability of cultured monocytes to lyse the targets is explained by a decrease in their ability to produce the soluble cytolytic factor. Both LPS and IFN-gamma modulated the effect of culturing. LPS exhibited a dual effect. Within 2-3 h after its addition, LPS enhanced the cytotoxic activity of monocytes by increasing the synthesis of CF. However, upon a longer incubation, the decay of the activity was more pronounced in the presence of LPS. IFN-gamma did not augment the cytotoxic activity of monocytes above the basal level, yet it prevented the loss of activity which accompanies the process of monocyte maturation to macrophages.

Animals↗
PubMed1986

Common bile duct compression by an abdominal aortic aneurysm.

A 76-year-old female was admitted to the hospital with oral bleeding. Laboratory findings were suggestive of disseminated intravascular coagulation. An endoscopic cholangiography was performed in order to rule out a biliopancreatic tumor. A symmetrical stenosis of the lower part of common bile duct was observed. This extrinsic compression was due to a calcified abdominal aortic aneurysm. CT scan confirmed the close relation between the common bile duct and the aortic aneurysm. No cholestasis was described.

Aged↗
PubMed1986

Efficient constitutive production of human IFN-gamma in Chinese hamster ovary cells.

A human genomic DNA segment of 5.6 kb containing the entire gene for immune interferon-gamma was fused through its 5'-untranslated region to the corresponding region of the simian virus 40 (SV40) T-antigen gene. The SV40 early promoter used contained a modified transcriptional enhancer element with a 93-bp repeat. Supercoiled plasmid DNA was used to transfect Chinese hamster ovary (CHO) cells, the selectable marker being a SV40-dihydrofolate gene construct. Constitutive expression of the IFN-gamma gene in primary transformants was high, especially if a Harvey murine sarcoma virus long terminal repeat (LTR) was present in addition to the SV40 promoter. After gene amplification by methotrexate selection, CHO-gamma cell lines were obtained that produce 1.5-2 million units of IFN-gamma per million cells and per day (200,000 molecules per cell per minute). Metabolic labeling showed that over 90% of the protein secreted by such cells is human IFN-gamma. A one-step immuno-affinity chromatography on monoclonal antibodies yielded pure IFN-gamma with 1-2 X 10(8) units/mg protein. Like IFN-gamma from human white blood cells, the IFN-gamma from CHO-gamma cells is a mixture of two glycoproteins of 26,000 and 20,000 daltons with traces of the unglycosylated 17,000-dalton polypeptide. Large-scale cultures in 1% serum routinely yield over 600,000 units of human IFN-gamma/ml culture per day.

Animals↗
PubMed1986

Human monocytes and lymphocytes produce different mixtures of alpha-interferon subtypes.

alpha-Interferon (IFN-alpha) was produced by either peripheral blood lymphocytes or by monocytes and purified by an anti-IFN-alpha affinity column. When these preparations were analyzed by reversed-phase HPLC, a difference in the distribution of IFN-alpha subtypes from the two cell types was found. While the two major subtypes of IFN from induced lymphocytes had apparent molecular weights of 20K and 21K, monocytes produce an additional subtype of molecular weight 26K in large quantities (50%). This subtype had greater activity on human cells than on bovine cells in comparison to other IFN-alpha subtypes.

Animals↗
PubMed1986

A neurotrophic factor derived from goldfish brain: characterization and purification.

Previous studies carried out in our laboratory have demonstrated that goldfish brain contains substances that promote neurite extension from regenerating retinae in culture. Fractionation of the brain extract by molecular sieving chromatography revealed the presence of several molecular species, including two peaks that have neurotrophic activity, representing low-molecular-weight substances. One peak was eluted (P-a) with an apparent molecular weight of about 13 kDa and was designated substratum neurite extension factor (SNEF) because it retained its neurotrophic activity when adsorbed onto the substratum. This recovered Sephadex fraction (P-a) when applied in vivo intraocularly caused an earlier capacity of the corresponding retinae to sprout in vitro. Thus, at 3 and 5 days after injury the neuritic growth indices from the factor-treated retinae were of 0.9 +/- 0.2 and 2.8 +/- 0.5, respectively, as compared with indices of 0.3 +/- 0.1 and 0.9 +/- 0.2, respectively, in retinae of injured but nontreated nerves. The factor was further purified by two steps of HPLC (ion exchange followed by reversed phase). The results showed that it is an acidic glycoprotein with an apparent molecular weight of 10 kDa.

Adsorption↗
PubMed1986

Essential fatty acid supplementation in tardive dyskinesia.

Preclinical and clinical observations suggest that enhancement of prostaglandin activity inhibits catecholamine release and may have antidyskinetic effects. A double-blind therapeutic trial with prostaglandin precursor essential fatty acids was conducted in 16 patients with tardive dyskinesia. No beneficial effects were seen.

Clinical Trials as Topic↗