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Biomedical subjects

B Segal

Publications and source records attributed to B Segal.

At least 19 recordsLinked to original sources
PubMed1995

Alcohol consumption and flushing response in natives of Chukotka, Siberia.

OBJECTIVE: Drinking patterns and flushing response were investigated among indigenous natives of Chukotka, Siberia (162 women, 139 men). The quantification of drinking behavior could be used for comparison with other northern peoples and as a baseline for future intervention. METHOD: Interviews, physical examinations and blood tests were performed in the Chukotka region of Siberia. RESULTS: 28% of the men and 4.5% of the women drank at least once per week. High doses per typical drinking occasion, which averaged 177.6 g of pure alcohol in men and 74.3 g in women, were reported; 10.3% of the men and 25.5% of the women reported that they experienced facial flushing after drinking. In most cases more than 20 g of alcohol was necessary to induce flushing, and two-thirds of the flushers were able to continue drinking after flushing began. No significant relationship between flushing and frequency and quantity of drinking and the prevalence of alcohol-related symptoms was found. There was a significant association between flushing by women and reports by them of their parent's flushing. CONCLUSIONS: Flushing by Chukotka natives and its relationship to drinking behavior is different from Oriental ALDH2-deficient flushing.

Adult↗
PubMed1995

Symmetry and synkinesis during rehabilitation of unilateral facial paralysis.

We evaluated biofeedback rehabilitation in patients with severe chronic unilateral facial paralysis, who had intact facial-motor innervation (House grades 3 to 5). Recovery of facial function was characterized (1) by grading facial movement symmetry, and (2) by counting the number of muscles exhibiting synkinesis during maximal execution of selected facial movements (e.g., smiling). Facial function in 21 patients typically improved by one House grade. Facial symmetry recovered rapidly during the first 5 months of treatment, and then improved more slowly. However, during this latter period, examination of the relationship between symmetry and synkinesis (visualized by a graph plotting symmetry grades on the x-axis, against the number of synkinetic muscles on the y-axis) indicated that overall facial control was improving even when House grading suggested that it was not. Such information should aid facial retraining and may clarify understanding of underlying rehabilitation mechanisms.

Adult↗
PubMed1995

Minimizing synkinesis during rehabilitation of the paralyzed face: preliminary assessment of a new small-movement therapy.

Neuromuscular rehabilitation can reduce the severity of chronic facial paralysis, but complete recovery is frequently impeded by synkinesis. We evaluated whether or not such synkinesis could be minimized by preventing its possible reinforcement during rehabilitation. We compared "standard" therapy, which uses the appearance of synkinesis to guide rehabilitation, with a new "small-movement" therapy, which uses smaller movements that should minimize possible subthreshold reinforcement of synkinesis. Ten subjects who had had facial paralysis for 0.5 to 27 years were randomly assigned to either therapy group. Blinded assessments were performed before and after ten 1-hour treatments given over a 1-month interval. Facial movements in both groups were significantly more symmetric after treatment. Although synkinesis tended to be reduced in the small-movement group, this reduction was not significant. The new therapy was at least as good as the standard one, and it may be better. Further studies are required to demonstrate this.

Adolescent↗
PubMed1995

Long-term effects of neuromuscular rehabilitation of chronic facial paralysis.

Although chronic facial dysfunction can be improved with neuromuscular biofeedback therapy, it is uncertain whether this improvement is maintained after such therapy ends, or whether post-therapy, home exercise programs optimize this improvement. We aimed to clarify these issues. Post-therapy facial function, in 38 previously treated patients, was blindly assessed using the House grading system, 1 to 41 months after ending therapy. Results were compared with pre-therapy function. It was found that post-therapy function was better than pre-therapy function in most patients (40%), it was worse in some (26%), and was unchanged in the rest. This surprising result occurred because, although most patients who recently stopped therapy (1 to 6 mo) had improved significantly, the longer other patients were out of therapy, the more they had tended to deteriorate, particularly those who had been practicing. Results suggested that unsupervised, post-therapy, home exercise programs may be detrimental, and that new post-therapy programs may be required to maintain the benefits of regular therapy.

Adolescent↗
PubMed1994

Urban-rural comparisons of drug-taking behavior among Alaskan youth.

This study explores drug-taking behavior among Alaskan youth in urban, rural, and semiurban communities. It finds significant differences among these locations, which are largely attributable to variations in age of first trying marijuana and alcohol. Racial group effects specific to initiation into marijuana, and gender differences related to initiation to alcohol, are also found. The implications of these findings for education and prevention of drug-taking behavior are discussed, with special emphasis on racial and cultural factors.

Adolescent↗
PubMed1994

The politicization of alcohol in the USSR and its impact on the study and treatment of alcoholism.

Conducting research, particularly social science or health-related research, in the former Soviet Union was difficult because of the intrusion of communist ideology on public policy, theory, research, and practice. This report provides a description of drinking and alcohol-related problems in Siberia that was not previously available for publication. It reviews how the Soviet State's policies effected the study and treatment of alcoholism in Russia, and presents a critical review of these policies that would not have been permitted under the previous regime.

Adult↗
PubMed1994

[Rationale for alcohol consumption and mitochondrial aldehyde dehydrogenase genotype in the native male population of Chukotka].

To study the alcohol consumption pattern and mitochondrial aldehyde dehydrogenase (ALDH2) genotype, a random sample consisting of 170 native males (Chukchee and the Eskimo), residents of 4 Chukotka settlements, was studied. According to interviews, most residents (68%) consumed alcohol once or twice a month; however during an alcohol uptake episode they consumed very high (intoxicating) doses exceeding 150 g of pure alcohol. The rates of control loss, alcohol amnesia and withdrawal syndrome were more than 50%. Twelve per cent reported inconsistent facial flushing after drinking and positive ethanol-patch test was found only in 2% of cases. Direct genotyping, using specific oligonucleotide probes, showed no atypical oriental type ALDH2. The normal genotype (ALDH2-1) was present in all the examinees from Chukotka natives (n = 87). These results explain the ability of Chukotka natives to consume high amounts of alcohol per occasion and they are in disagreement with the hypothesis that the drinking pattern among the natives is explained by specific features of alcohol-metabolising enzymes.

Adult↗
PubMed1993

Serum and salivary responses to oral tetravalent reassortant rotavirus vaccine in newborns.

Serum and salivary responses of 95 infants to either a standard (4 x 10(4) plaque-forming units (PFU), 47 neonates) or a high dose (4 x 10(5) PFU, 48 neonates) of tetravalent reassortant rhesus rotavirus vaccine (administered at 2 days and at 6 weeks of age) were evaluated in a double-blind clinical trial. Serum and salivary IgA antibodies to the rotavirus group A common antigen were determined by ELISA and radioimmunoassay (RIA). Serum neutralizing antibodies to rhesus rotavirus were determined by fluorescent focus reduction assay. No significant differences in responses to the high versus standard dose were noted in serum or saliva. Response was influenced by cord blood antibodies. All infants who were cord blood-negative for rhesus rotavirus neutralizing antibodies (nine who received the standard dose and 20 who received the higher dose) had serum responses, compared with 42-70% of those who were cord blood-positive. The serum response rate recorded for babies with cord blood neutralizing titres > 1000 was 44%. Infants being bottle fed had a higher serum response rate than did babies being breast fed exclusively. If serum and salivary responses were combined, the response rate reached 80% for bottle fed infants. Thus, determination of serum responses alone underestimates vaccine 'take' in infants, and more so in highly endemic areas than in areas subject only to sporadic outbreaks. However, determination of salivary responses in newborn breastfed infants may be inaccurate, due to possible persistence of antibodies derived from colostrum or breast milk.

Antibodies, Viral↗
PubMed1991

Conductivity response of porous electrodes supported on perfluorosulfonic acid membranes to acidic gas mixtures.

Gold or platinum films deposited on a Nafion membrane were used to measure surface conductance of the membrane. Acidic gases such as HCI or SO2, introduced as mixtures with an inert gas, were found to affect the conductance of the membrane surface facing this mixture while the other side of the membrane was constantly supplied with a moist inert gas. The relative conductance (G/Go) is most affected within the 0-0.5 and 3-4.5 vol % ranges both for HCI and SO2. The effect is higher for the Pt-deposited than it is for the gold-deposited membrane: for an HCI concentration of 1.5 vol %, G/Go is 5 for Pt deposited on Nafion while it is only 1.3 for gold deposited on Nafion. This is attributed to different geometries and porosity of the Pt and Au electrodes. No conductance response was observed for CO2 which yields with water a much weaker acid than those formed by HCI and SO2.

Electric Conductivity↗
PubMed1991

Adaptive plasticity in the gaze stabilizing synergy of slow and saccadic eye movements.

When a normal human subject is briefly turned in total darkness while trying to "look" at a spatially fixed target, the vestibulo-ocular reflex (VOR) produces slow-phase compensatory eye movements tending to hold the eyes on target. However, slow-phase compensation per se is generally inadequate in these circumstances. Nevertheless it has recently been found, that even in the dark, this inadequacy tends to be corrected by supplementary saccades usually acting in the compensatory direction. The present study further investigates this phenomenon by measuring the respective contributions of saccadic, slow-phase and overall net compensation in 9 subjects tested before and after 30% adaptive attenuation of VOR slow-phase gain. In each test series, subjects attempted to stabilize their gaze on a previously seen target during each of 40 brief (approximately 0.5 s) whole body rotations (40 degrees/s, 20 degrees amp) conducted in complete darkness. The adaptive experience comprised 2 h of full-field visual suppression of the VOR during sinusoidal rotation of subject and surround at 1/6 Hz and 40 degrees/s velocity amplitude. Before adaptation, the cumulative slow-phase and cumulative saccadic components produced on average 78% and 14% respectively of the ideal (100%) compensation, thus yielding an overall net compensation which was 92% of the desired value. After adaptation, the corresponding values in the same population were 53%, 18% and 71% respectively. Thus after adaptation, the combined saccadic-slow-phase response brought the final gaze position to a point in space that was systematically shifted in the direction of head rotation (i.e. undercompensation). Subjects re-exposed to 30 min of normal visual-vestibular interaction displayed a variety of recovery patterns using different combinations of slow and saccadic eye movements. However, there was a consistent "synergistic" tendency for saccadic eye movements to improve slow-phase performance, regardless of the subject's adaptive state. In one subject, compensatory saccadic eye movements corrected a consistent directional asymmetry in the slow-phase response. It is suggested that a conscious vestibular percept of self-rotation might underlie the combined saccadic-slow-phase response, and that the net under performance after adaptation might reflect attenuation of this percept relative to the actual rotational stimulus.

Acclimatization↗
PubMed1991

Adaptive modification of vestibularly perceived rotation.

Results from Bloomberg et al. (1991) led to the hypothesis that saccades which accompany the dark-tested vestibulo-ocular reflex (VOR) tend to move the eyes towards a vestibularly derived percept of an intended oculomotor goal: also that this is so even when that percept has been adaptively modified by suitably prolonged visual-vestibular conflict. The present experiments investigate these implications by comparing the combined VOR + saccade performance with a presumed "motor readout" of the normal and adaptively modified vestibular percept. The methods employed were similar to those of an earlier study Bloomberg et al. (1988) in which it was found that after cessation of a brief passive whole body rotation in the dark, a previously seen earth-fixed target can be accurately located by saccadic eye movements based on a vestibular memory of the preceding head rotation; the so-called "Vestibular Memory-Contingent Saccade" (VMCS) paradigm. The results showed that the vestibular perceptual response, as measured after rotation by means of the VMCS paradigm, was on average indistinguishable from the combined VOR + saccade response measured during rotation. Furthermore, this was so in both the normal and adapted states. We conclude that these findings substantiate the above hypothesis. The results incidentally reaffirm the adaptive modifiability of vestibular perception, emphasing the need for active maintenance of its proper calibration according to behavioural context.

Acclimatization↗
PubMed1991

Adolescent initiation into drug-taking behavior: comparisons over a 5-year interval.

Acquisition curves for six substances were compared for adolescents in two samples separated by a 5-year interval. Individual variations in initiation ages were found for different substances, but the general pattern of exposures to drugs was essentially stable over the time interval. The findings suggest that there appears to be a range of first experience with drugs that extends from 13 to 16 years. Special emphasis was given to the implications which the findings have for education and intervention programs, and for further research.

Adolescent↗
PubMed1991

Haptoglobin levels among alcoholics in Alaska.

The levels of haptoglobin, plasma proteins and amino acids were studied in a non-fasting population of alcoholics. In 25 subjects, only small differences were seen between the means when Native subjects were compared to non-Native. There did not appear to be any acute phase response differences between these two groups. This study did not substantiate other reports on the correlation of the severity of alcoholism with glycoprotein synthesis.

Alaska↗
PubMed1990

AIDS cardiomyopathy: first rule out other myocardial risk factors.

Consecutive autopsies of 59 male AIDS patients revealed that 21 had other myocardial risk factors: 17 were alcohol abusers and 6 had hypertension or coronary artery disease. AIDS patients with these myocardial risk factors were older (mean age 45 versus 35 years, P less than 0.01), and were more likely to have cardiomegaly (mean heart weight 397 grams versus 350 grams, P = 0.06) than patients with AIDS alone. When evaluating patients for AIDS cardiomyopathy, other myocardial risk factors must be considered.

Acquired Immunodeficiency Syndrome↗
PubMed1990

Effects of methylphenidate on adolescents with aggressive conduct disorder and ADDH: a preliminary report.

The effect of methylphenidate on aggression in adolescents diagnosed with both aggressive conduct disorder and attention deficit disorder with hyperactivity was assessed in nine male adolescents. After three open trials, a placebo controlled double-blind design was used. During methylphenidate treatment of the six double-blind subjects, there was a significant reduction of aggressivity (p's less than 0.05), as measured by the Adolescent Antisocial Behavior Checklist. Conners Teacher Rating Scale Hyperactivity and Aggression scores were in the predicted directions, but the differences were not statistically significant.

Adolescent↗