Community recognition of objective and subjective characteristics of depression.

Assessed knowledge of depression in a random sample of 527 community-living adults. Vignettes were presented which described a young or old protagonist with depressive symptoms. Respondents were asked to identify potential problems and possible solutions. A depression information measure followed. Results indicated that community residents were aware of many objective features of depression although they identified less information about treatment issues. Older respondents were least informed. Although there were no gender differences in objective knowledge, men were less likely to mention depression with regard to the vignettes. Suggestions for implementing more effective community interventions are discussed.

The relationship between internal attentional control and sleep-onset latency in elderly adults.

Cognitive hyperactivity has been hypothesized to be one cause of sleep-onset insomnia in elderly adults. This study examined the relationship between one factor that may mediate cognitive hyperactivity--internal attentional control, the ability to direct and control one's attention while processing stimuli from memory--and sleep-onset latency. Twenty-six elderly individuals with self-reported sleep-onset latencies ranging from 5 to 75 min were brought into a sleep laboratory for a multimethod assessment of internal attentional control. Factor analysis was used to develop a composite measure of this construct. Each person then completed three 2-hr afternoon naps while multiple electrophysiological responses were monitored. The results of canonical correlations with the derived composite scores suggested that a significant proportion of the variance in sleep-onset latency in elderly adults was related to internal attentional control.

The utility and validity of daytime naps in the assessment of sleep-onset insomnia.

This study examined the discriminant validity, consistency, and reactivity of afternoon naps for assessing sleep-onset insomnia. Eleven insomniac and 17 noninsomniac subjects came to a sleep laboratory for three afternoon naps while multiple electrophysiological and subjective measures were taken. The results indicated that sleep-onset latencies during the afternoon naps significantly discriminated between insomniac and noninsomniac subjects. Further, significant correlations were found among most measures of sleep-onset latency measured both electrophysiologically and subjectively. The proportion of variance in sleep-onset latency accounted for by groups (insomniac vs. noninsomniac) increased over the three naps. Finally, a comparison of the results from this study with those from three all-night studies using identical facilities and procedures revealed that the sleep-onset latencies from this nap study were within the ranges expected on the basis of the all-night studies.

Electrophysiological correlates of adult decisions made during a conservation of quantity task.

Visual evoked responses were recorded from 10 scalp locations over the left and right hemisphere while adults were involved in a conservation of quantity task. Multivariate analyses involving principal components analysis and ANOVA identified bilateral and left hemisphere lateralized components of the visual evoked responses which discriminated between conservation judgments made by subjects.

Preliminary studies on the response of Plasmodium falciparum to chloroquine in the Philippines, with the in vitro technique.

Previous investigations had shown that resistance to standard regimens of chloroquine occurred in some cases of falciparum infection in the Philippines. More extensive investigations into this phenomenon were planned by the Malaria Eradication Service, by means of the in vitro technique developed by Rieckmann, in order to determine both the distribution of resistant strains throughout the country and their local incidence. Before these studies were undertaken, a series of observations were made on cases of falciparum malaria encountered in Manila and its environs, to assess the reaction of local strains of the parasite to the in vitro test. These cases were also treated with standard doses of chloroquine and some were followed up for 4 weeks to compare the predictions made as a result of the in vitro tests with the in vivo observations. Of the 34 in vitro tests carried out, 18 were followed up in vivo. In 8 cases, no recrudescence occurred, but in the other 10 recrudescences were detected during the 4-week observation period, thus indicating parasite resistance to the drug. In each of the 18 cases, the in vivo response followed the in vitro prediction.

Identification of malaria parasites by fluorescence microscopy and acridine orange staining.

The need for a technique that is more sensitive than the use of Romanowsky-stained thick blood films for detecting malaria parasites at low concentration in the blood is well recognized. One of the more promising methods appeared to be fluorochrome staining with acridine orange. However, reports on the efficacy of the technique were contradictory and it was not clear to what extent blood films taken under survey conditions would contain fluorescing artefacts that might confuse diagnosis. An investigation indicated that, provided reasonable care was taken, blood films made under survey conditions contained few confusing artefacts. However, it was found that, while acridine orange staining might have a slight advantage when large malaria parasites were present, it was inferior to routine Romanowsky staining for the detection of young trophozoites, the inferiority becoming more pronounced as the parasite concentration decreased.

A comparative study of thick and thin blood films in the diagnosis of scanty malaria parasitaemia.

In an attempt to explain the shortcomings of the routine thick-film examination in the diagnosis of scanty malaria parasitaemias, a direct comparison, in terms of positivity and parasite counts, was made between the results of routine thick-film study and long-term examination of thin films taken at the same time from the same individuals. Calculation of the average thickness of the thick and thin films prepared allowed these comparative results to be corrected according to the actual volume of blood examined. From these corrected figures it was observed that both parasite counts and positivity were significantly higher in the thin-film series, and it has been deduced that heavy losses in parasites, varying from 60% to 90%, occurred during the dehaemoglobinization and staining of thick films.The epidemiological implications of this finding in malaria practice are discussed. Emphasis is laid on the importance of further research in order to improve the sensitivity of the routine thick film in the diagnosis of the scanty parasitaemias met with in the later stages of malaria-eradication programmes.