Effect of emotional stress on the frequency of chromosome aberrations in the bone marrow cells of mice

The chromosome aberration rate was studied in bone marrow cells of C57BL/6, CBA and BALB/c mice before and after emotional stress. After "the opened field" experiment the chromosome aberration rate in C57BL/6 and CBA mice increased while that in BALB/c mice remained unchanaed. The mutagenic effect was prevented by phenazepam.     

Colony-forming ability of ultraviolet-irradiated xeroderma pigmentosum fibroblasts from different DNA repair complementation groups

In two related studies, a combination of reinforcement for incompatible behavior and positive practice overcorrection was applied to the elimination of head-slapping and head-banging behavior exhibited, respectively, by two profoundly retarded boys. The design for both studies also included a period in which only reinforcement for incompatible behavior was applied. The results from Study 1 indicated that, while reinforcement had little effect in reducing the frequency of the learner's head slapping, the combination of reinforcement and overcorrection had an immediate effect in significantly reducing and eventually eliminating that behavior. A 4-month follow-up indicated no significant recurrence of the behavior. In Study 2, on the other hand, both reinforcement and the combination of reinforcement and overcorrection resulted in a significant increase in the frequency of the learner's head-banging behavior. Discussion centered on several research questions left unanswered by the differing effects of the procedures applied in both studies.     

Diagnosis on death certificates of sudden death due to ischemic heart disease

This study was undertaken to evaluate the quality of diagnoses of sudden death (SD) caused by ischemic heart disease (IHD) on death certificates. A random sample of 10% (100 cases) was drawn from all such deaths which occurred in 1970 among Oklahoma City residents. The medical records of each case were reviewed and the quality of the diagnosis was rated, by the use of predetermined standard criteria, as confirmed and valid or unconfirmed and invalid. Among 100 IHD deaths, SD constitute 45%. Of these SDs, 18% were unobserved, without information as to the manifestations of the attack or the interval from onset of symptoms to death. According to criteria of the American Heart Association and WHO Expert Committee, the diagnosis in this 18% was unconfirmed and invalid. Thus there is insufficient quantitative evidence to justify the use of SD, as found on death certificates, as an indication of frequency of ischemic heart disease.     

Relationships between hearing loss and cognition in normally hearing aged persons

The relationships between mild hearing losses and cognitive functioning were studied for two independently selected samples of aged subjects whose hearing was within normal limits. One group had 47 males of mean age 71.5 (SD 4.8) who were selected for their excellent health status. The second group consisted of 38 females of mean age 75.9 (SD 5.3), all of whom had some significant physical pathology. Hearing losses at various frequency levels (from 125 to 8000 cps) were correlated with performance on cognitive tests such as the WAIS, with age effects then being partialled out. The results reveal substantial associations between hearing losses and scores achieved on the intellectual measures for both samples. Verbal type tests show these relationships much more extensively than the performance tests. The findings imply that aged subjects may be more intellectually capable than their test performances suggest and that hearing is an important variable to be considered in the assessment of their cognitive functioning.     

Serologic response to revaccination with two rubella vaccines

Three years after receiving rubella vaccine, 1,060 elementary school children living on the island of Maui, Hawaii, were revaccinated with either HPV-77 DE-5 or RA 27/3 rubella vaccine given subcutaneously or intranasally in order to compare the effectiveness of these two vaccines in raising antibody titers. RA 27/3 was the more effective booster vaccine, producing fourfold or greater titer rises in 20.1% of recipients, including 80% of children with hemagglutination-inhibiting antibody titers less than or equal to 1:40 at the time of revaccination, intranasal revaccination was not significantly more effective than subcutaneous revaccination, although it did elicit higher titers in children who responded. Responses differed according to the vaccine that children had received three years earlier. Because antibody titers have persisted in vaccinated children, routine administration of a second dose of rubella vaccine is not currently recommended.     

Cholera in Lima, Peru, correlates with prior isolation of Vibrio cholerae from the environment

The authors utilized a recently developed DNA probe technique to obtain quantitative data on occurrence of Vibrio cholerae in samples collected monthly from 12 environmental sites in Lima, Peru, from November 1993 through March 1995. Peak V. cholerae counts ranged from 10(2)/ml to 10(5)/ml, with the highest counts in sewage-contaminated areas and irrigation water. With our methodology, no V. cholerae cases were detected at any site during the winter months of July through October. Counts were detectable in the environment before onset of cholera in the community, with counts at "cleaner" sites upriver correlating significantly with occurrence of community disease 2 and 3 months later. In sites with heavy sewage contamination, V. cholerae could still be detected before the onset of cases in the community; however, in contrast to upriver sites, counts at these latter sites correlated most closely with the number of concurrently occurring cholera cases. These data support a model of cholera seasonality in which initial increases in number of V. cholerae in the environment (possibly triggered by temperature) are followed by onset of illness in the community, with these human cases further amplifying the organism as the epidemic cycle proceeds.