Biomedical subjects

M Almagor

Publications and source records attributed to M Almagor.

At least 37 records · Page 2Linked to original sources

PubMed1993

Simultaneous swim-up/swim-down of sperm in assisted reproduction procedures.

PURPOSE: High-quality motile human spermatozoa were obtained following treatment of semen by simultaneous swim-up into medium and swim-down into an isotonic 40% Percoll solution. RESULTS: This procedure was significantly better than the swim-up method and comparable to discontinuous Percoll gradient centrifugation. Recovery rates of motile sperm were 35% for swim-up, 65% for Percoll gradient centrifugation, and 73% for swim-up/swim-down. CONCLUSION: The swim-down sperm was inferior to the swim-up sperm in its upward migration capacity but superior in morphology. Spermatozoa obtained by the swim-up/swim-down procedure demonstrated fertilizing ability in IVF, and clinical pregnancies were established. The simultaneous swim-up/swim-down procedure offers an alternative efficient method of simple separation of high-quality motile sperm for various assisted reproduction techniques.

Cell Separation↗

PubMed1993

Incremental validity of the MMPI-2 Content Scales in the assessment of personality and psychopathology by self-report.

The incremental contribution of the MMPI-2 Content Scales to the prediction of scores on self-report measures of personality and psychopathology was investigated. The MMPI-2, Beck Depression Inventory, State-Trait Personality Inventory, and Symptom Checklist-90-Revised were administered to 596 subjects: 339 women and 257 men. Zero-order correlational analyses indicated that both clinical and Content Scales correlated with each of the criterion measures. In all but one case, an MMPI-2 Content Scale was found to have the highest correlation with the extratest variables. Combined hierarchical, stepwise regression analyses demonstrated that the MMPI-2 Content Scales possess incremental validity vis-à-vis the clinical scales for both genders in relation to all of the criterion measures. Additional analyses indicated that the MMPI-2 clinical scales also possess incremental validity vis-à-vis the Content Scales. However, the incremental contribution of the clinical scales was of lesser magnitude. Implications of these findings for test interpretation and future research with the MMPI-2 are discussed.

Adolescent↗

PubMed1993

Comprehensive individualised nonpharmacological treatment programme for hypertension in physician-nurse clinics: two year follow-up.

A comprehensive programme of nonpharmacological control of hypertension (balanced nutrition, satisfactory weight, enhanced physical activity, relaxation technique, smoking cessation) by primary care physician-nurse (PN) teams who were instructed and routinely advised by a paramedical professional (PP) team (psychologist, nutritionist and physical activity instructor) was developed with the aim of increasing long-term compliance. To evaluate effectiveness, 52 mild and moderate hypertensives without target organ damage were randomly allocated to six weekly meetings of individual intensive instruction by PN teams alone, or direct group instructions by PP teams (24 and 28 patients, respectively). The respective results at 11 months and 24 months follow-up compared with baseline were: (1) 56.9% and 58.8% showed minimal satisfactory reduction of weight, (2) 49% and 58.8% showed minimal satisfactory increase in physical activity, (3) the reported increase in physical activity at 11 months follow-up was validated by significantly correlated improved performance in ergometry, (4) 75% and 40% of the patients performed relaxation vs. 2% at baseline and (5) 71% and 59% needed no medication or reduced dose to control BP, and these changes were significantly (P < 0.02) correlated with weight reduction and increased physical activity. As no differences were found between the two modes of treatment, we conclude that our programme can be successfully applied by the PN primary care teams to increase adherence to nonpharmacological measures in the control of hypertension.

Adult↗

PubMed1992

Density differences between spermatozoa with antisperm autoantibodies and spermatozoa covered with antisperm antibodies from serum.

Autoantibody-carrying spermatozoa from infertile men were processed using a discontinuous Percoll gradient. The treatment yielded a sperm fraction with significantly reduced antibody loading on the sperm head but did not affect antibody binding to the sperm tail. The immunodepleted sperm preparation demonstrated fertilizing ability when used in in-vitro fertilization. Normal, antibody-free semen samples were coated in vitro with antisperm antibodies from serum, followed by Percoll gradient centrifugation. No significant separation of antibody-free spermatozoa was obtained, regardless of the antibody binding site.

Antibodies↗

PubMed1992

Vasoactive therapy versus placebo in the treatment of sudden hearing loss: a double-blind clinical study.

Twenty-seven patients suffering from sudden sensorineural hearing loss (SHL) were randomly assigned to one of two groups: a treatment group (n = 13) receiving intravenous procaine and low-molecular-weight dextran, and a placebo control group (n = 14). The effect of treatment was analyzed by means of an analysis of variance and covariance procedures. Results indicated nonsignificant differences between the groups on all outcome indices measured. Sex, age, time since the onset of symptoms to the initiation of therapy, audiogram configuration, and initial severity of hearing loss did not significantly affect the results. These findings suggest that the therapeutic effects of this vasodilator are not superior to a placebo.

Adult↗

PubMed1991

Psychopathology associated with sexual dysfunction.

The association between sexual disorders and psychological functioning was investigated in this study. Seventy-eight subjects who applied for sex therapy were divided into the following groups: Sexual Desire (SDD) and Erectile Disorder; Orgasm (ORG) and Premature ejaculation (PME) disorders. Fifty-six sexually functional subjects served as matched controls. The MMPI was administered to all subjects. The results indicated that the SDD and Erectile groups produced the most disturbed profiles, while the ORG and PME groups yielded profiles within normal limit (WNL). A good fit of individual to group profiles was found for SDD, but not for PME and ORG; thus, clinical interpretation was possible for the former only.

Adult↗

PubMed1991

Mood changes during the menstrual cycle and their relation to the use of oral contraceptive.

The relation between the use of oral contraceptives and changes in positive and negative affect over the course of the menstrual cycle was studied in 50 women who completed a mood questionnaire daily during their menstrual cycle. Results indicated that users of oral contraceptives experience a higher level of positive affect during the cycle than do non-users. Positive affect scores were significantly higher than negative affect scores in the menstruation, follicular and luteal phases of the cycle. There were no significant differences between the groups and no discernible phasic changes on negative affect. Discussion of these findings centers on their implications concerning the relation between positive affect and oral contraceptives, the support they provide for the independence of positive and negative affect, and future directions for research in this area.

Adolescent↗

PubMed1990

Retinoic acid inhibits the myristoylation of a membrane protein in HL-60 cells.

Incubation of nondifferentiated HL-60 cells with high specific activity myristic acid results in myristoylation of a 25 KD membrane protein. Myristoylation was inhibited by retinoic acid but not by DMSO, thus indicating that the nonmyristoylated state induced by retinoic acid is causal to rather than the result of the overall differentiation sequel induced. Similarly, incubation of HL-60 cells with high specific activity retinoic acid results in specific retinoylation of a membrane protein of similar molecular mass. The two acylated proteins could however be separated by 2-D gel electrophoresis, thus indicating that inhibition of myristoylation by retinoic acid could not be accounted for by competition between retinoic and myristic acids for the same acylated site.

Cell Differentiation↗

PubMed1990

Glycosidase activities of mycoplasmas.

The activities of alpha- and beta-glucosidase, beta-galactosidase and beta-N acetylglucosaminidase were assessed at acidic pH by fluorimetry using the appropriate 4-methylumbelliferyl substrate in four Mycoplasma species (M. pneumoniae, M. gallisepticum, M. hominis and M. capricolum) and in Acholeplasma laidlawii. The glycosidase activities were in a low range (0.1-4.2 nmole per h per mg protein) with the exception of higher activities of beta-N-acetylglucosaminidase in A. laidlawii. The enzyme levels of a virulent and a nonvirulent strain of M. pneumoniae were comparable. Despite the very sensitive assay, neuraminidase activity was not detected in M. pneumoniae and M. gallisepticum. No induction of alpha-glucosidase could be demonstrated for M. pneumoniae or A. laidlawii. At least part of the glycosidase activities was localized in the membrane fraction of all mycoplasmas studied. This may support the hypothesis that pathogenic mycoplasmas, being membrane parasites, may modify, by their glycosidases, some host cell glycoconjugates. However, our study did not distinguish the pathogenic mycoplasmas to possess a characteristic glycosidase profile.

Acetylglucosaminidase↗

PubMed1990

Personality correlates and cyclicity in positive and negative affect.

The current study investigated over time variation of Positive and Negative Affect and the relation between mood level and personality characteristics. 68 male undergraduate volunteers completed the Multidimensional Personality Questionnaire and then recorded mood ratings daily over a 29-day period. Spectra time series analyses showed a distinct and significant seven-day cycle for Positive Affect and Negative Affect, with the peak in Negative Affect occurring approximately three days after that of Positive Affect. Positive Affect was significantly correlated with scores on Well-being, Social Closeness, Social Potency, and Absorption scales of the questionnaire, while Negative Affect was significantly related to scores on the Stress-Reaction, Alienation, and Aggression scales.

Adult↗

PubMed1989

Differential scanning calorimetry of nuclei as a test for the effects of anticancer drugs on human chromatin.

Differential scanning microcalorimetry of nuclei from cultured cells revealed differences between antitumor drugs in potency and mechanism. Scanning calorimetry of nuclei showed four structural transitions as the temperature was raised from 25 to 120 degrees C. Transitions II (76 degrees C), III (88 degrees C), and IV (105 degrees C), respectively, characterize the denaturation of the nucleosome, the unstacking of bases in nicked DNA after release from the nucleosome and unstacking in the released intact, supercoiled DNA. Nuclei from human epithelial cells treated with the DNA strand breakers bleomycin and streptonigrin showed an increase in transition III at the expense of transition IV. The effect was dose dependent. At intermediate times of treatment a substantial portion of the chromatin melted between the temperatures of transitions III and IV and this was taken to represent intact supercoiled DNA in which base-pairing had been weakened by loss of some bases. Treatment of cells with the alkylating agents N-nitroso-N-methylurea and mitomycin C gave results similar to those of the strand-breaker antitumor drugs, except that they were less potent. Irradiation by UV gave similar effects. The effects of intercalating drugs were quite distinct from those produced by strand breakers or alkylators. Nuclei from cells incubated with increasing doses of actinomycin D or ethidium bromide gave calorimetric scans that indicated progressive denaturation of the nucleosome and a concomitant stabilization of supercoiled DNA. The loss of transition IV during drug treatment was correlated with the loss of cellular capacity to divide, regardless of which drugs were used.

Alkylating Agents↗

PubMed1989

Changes in chromatin structure during the aging of cell cultures as revealed by differential scanning calorimetry.

Nuclei from cultured human cells were examined by differential scanning calorimetry. Their melting profiles revealed four structural transitions at 60, 76, 88, and 105 degrees C (transitions I-IV, respectively). In immortalized (i.e., tumor) cell cultures and in normal cell cultures of low passage number, melting profiles were dominated by the 105 degrees C transition (transition IV), but in vitro aging of normal and Werner syndrome cells was associated with a marked decrease in transition IV followed by an increase in transition III at the expense of transition IV. At intermediate times in the aging process, much DNA melted at a temperature range (95-102 degrees C) intermediate between transitions III and IV, and this is consistent with the notion that aging of cell cultures is accompanied by an increase in single-strand character of the DNA. Calorimetric changes were observed in the melting profile of nuclei from UV-irradiated tumor cells that resembled the age-induced intermediate melting of chromatin. It is suggested that aging is accompanied by an increase in single-stranded character of the DNA in chromatin, which lowers its melting temperature, followed by strand breaks in the DNA that destroy its supercoiling potential.

Calorimetry, Differential Scanning↗

PubMed1989

In physiological salt conditions the core proteins of the nucleosomes in large chromatin fragments denature at 73 degrees C and the DNA unstacks at 85 degrees C.

Previous studies of chromatin melting had been done at low salt concentrations to maintain optically clear solutions permitting observation of hyperchromic effects that accompany the unstacking of bases in DNA. Scanning calorimetry does not require clear solutions and so allowed more nearly physiological levels of salt to be used in the present work. HeLa chromatin went through two major structural transitions of 73 and 85 degrees C in 150 mM NaCl, 1 mM MgCl2, 1 mM CaCl2. Proteinase K treatment eliminated the 73 degrees C transition without affecting the other one. DNase I digestion eliminated the 85 degrees C transition and shifted the other from 73 to 58 degrees C. Supported by previous reports that salt concentrations like these would largely eliminate the effect of histones on the Tm of DNA, the present observations indicate that the collapse of the core histone complex occurs at 73-76 degrees C (transition II) and the nucleosomal DNA unstacks at 85-87 degrees C (transition III). They also show that the thermal stability of the histone octamer is enhanced by the DNA folded around it in the nucleosome; although the histone core raises the Tm of the DNA in low salt, in physiological salt conditions it is the DNA that stabilizes the protein complex.

Buffers↗

PubMed1989

The two-factor model of self-reported mood: a cross-cultural replication.

The cross-cultural stability of a two-factor model of self-reported mood was studied in Israel. Sixty women and 25 men filled out a 58-adjective Mood Check List, everday for 45 consecutive days. Replicatory factor analyses demonstrated that the two-factor model of mood is applicable to both Israeli men and women and that this structure is consistent across American and Israeli cultures. Three implications of these findings are discussed. Replication of this structure in a diversified and unique culture, such as Israel, coupled with a previous replication in Japan (Watson, Clark, & Tellegen, 1984), is interpreted as lending considerable support to the assertion that this model of mood is cross-culturally consistent. Theoretical formulations and empirical findings derived and discovered in the U.S. can now be employed in planning and interpreting mood studies in Israel. The results of such studies can be incorporated within the general body of knowledge accumulating on this topic in the U.S.

Adult↗

PubMed1987

A high melting (105 degrees C) form of chromatin characterizes the potential of cells for mitosis.

The nuclei from different types of dividing cultured cells melted as four thermal transitions: I (60 degrees C), II (76 degrees C), III (88 degrees C), and IV (105 degrees C). The fourth transition was the predominant endotherm in all types of cells examined. In the melting profile of nuclei obtained from nondividing density-inhibited fibroblasts, transition IV remained the major endotherm; however, it was lost in nuclei from differentiated myoblasts and nutrient-depleted cells. In these cells, the loss in transition IV was compensated by a concomitant increase in transition III. In the nutrient-deprived cells the decrease in transition IV was followed by a gradual lowering in its melting temperature. The complete loss of transition IV was correlated with loss of cellular capacity to divide.

Animals↗

PubMed1986

Protective effects of the glutathione redox cycle and vitamin E on cultured fibroblasts infected by Mycoplasma pneumoniae.

The role of the glutathione (GSH) redox cycle and vitamin E as antioxidant defense systems was studied in normal human cultured skin fibroblasts infected by virulent Mycoplasma pneumoniae. In cells infected for 20 h, catalase activity was inhibited by 75% and the intracellular GSH decreased to 32% of its normal values. GSH peroxidase and oxidized glutathione (reductase activities in the infected cells were unaffected.) GSSG glutathione in the medium of the infected cells rose in accordance with the intracellular GSH decrease. The observed elevation in GSSG/GSH ratio was attributed to the increase in intracellular H2O2 content in M. pneumoniae-infected cells due to the marked inhibition in their catalase activity. The protective effect of the GSH redox cycle in infected cells was studied by depletion of cellular GSH, prior to their infection with M. pneumoniae, using buthionine sulfoximine (BSO), a selective inhibitor of gamma-glutamyl cysteine synthetase. After 16 h of incubation with BSO, the GSH levels were reduced to 38% of their normal value and recovered to 55% during 24 h after removal of the inhibitor. BSO had no effect on GSH peroxidase and catalase activities in either infected or noninfected cells. The level of malonyldialdehyde (an indicator of membrane lipid peroxidation) in BSO-treated cells infected by M. pneumoniae was 1.8 times higher than in infected controls. Cells enriched with 0.25 and 2.25 micrograms of vitamin E per mg of protein prior to their infection by M. pneumoniae revealed the following: a lesser degree of catalase inhibition, 46 and 30%, respectively, versus 64% in infected control cells that were not supplemented with vitamin E; lower levels of malonyldialdehyde, 55 and 20% increments, respectively, versus a 140% increment in infected controls; higher residual activity of lactate dehydrogenase, 76 and 96%, respectively, versus 58% in infected controls. Our data indicate that the oxidative damage induced in M. pneumoniae-infected cells due to the increase in intracellular levels of H2O2 and O2- is limited by the host cell GSH redox cycle and by supplementation with vitamin E.

Buthionine Sulfoximine↗

PubMed1985

Human ciliated epithelial cells from nasal polyps as an experimental model for Mycoplasma pneumoniae infection.

Human ciliated epithelial cells derived from nasal polyps and cultured in a monolayer were studied as an experimental model for Mycoplasma pneumoniae infection. Scanning electron microscopy revealed two types of cultured epithelial cells: one which was covered by microvilli only and another which had microvilli and actively beating cilia. M. pneumoniae adhered to both types of cells, and the adherence followed saturation kinetics as a function of time. Infection of the cells for 20 h resulted in 75% inhibition of their intracellular catalase activity and a 3.5-fold increase in their malonyldialdehyde levels compared with noninfected controls. This indicates the presence of cellular oxidative damage due to M. pneumoniae infection. It is suggested that human nasal ciliated epithelial cells may serve as a representative model for studying M. pneumoniae in relation to its natural host.

Adhesiveness↗

PubMed1984

Role of superoxide anion in host cell injury induced by mycoplasma pneumoniae infection. A study in normal and trisomy 21 cells.

The role of Mycoplasma pneumoniae-generated superoxide and hydrogen peroxide in inducing host cell injury was studied in normal and trisomy 21 human cells. As a result of M. pneumoniae infection, catalase activity in infected normal skin fibroblasts and ciliated epithelial cells decreased by 74-77% as compared with uninfected controls. Addition of superoxide dismutase to the infected cultured cells totally prevented the inhibition whereas addition of catalase or catalytically inactivated superoxide dismutase had no protective effect. Trisomy 21 erythrocytes and cultured skin fibroblasts in which CuZn-superoxide dismutase content is 50% greater than in normal cells were infected by M. pneumoniae. The inhibition of catalase activity in these cells was 7-33% and 0-20.5%, respectively, as compared with 65-72% and 48-68% inhibition in normal infected controls. Following M. pneumoniae infection, the levels of malonyldialdehyde, an indicator for membrane lipid peroxidation were raised in trisomy 21 cultured fibroblasts by 10-32% while in normal cells malonyldialdehyde increased by 140-870%. Externally added superoxide dismutase, but not catalase, reduced the extent of lipid peroxidation in normal infected cells. Lactate dehydrogenase release from normal infected cells was time correlated with the increase in their malonyldialdehyde formation. It is suggested that superoxide generated during M. pneumoniae infection is involved in the inhibition of host cell catalase activity. The inactivation of this cellular antioxidative defense mechanism results in progressive oxidative damage to the M. pneumoniae-infected cells.

Catalase↗