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Biomedical subjects

D A Sack

Publications and source records attributed to D A Sack.

At least 127 records · Page 7Linked to original sources
PubMed1987

Neuroendocrine response to 5-hydroxytryptophan in seasonal affective disorder.

A double-blind random-ordered comparison of the effects of placebo and 5-hydroxytryptophan (200 mg, orally) in ten depressed patients with seasonal affective disorder (SAD) and ten controls disclosed slightly but significantly higher basal levels of serum prolactin and a trend toward higher basal levels of serum cortisol in the patients with SAD compared with controls. After administration of 5-HTP, the cortisol level significantly increased and the prolactin level significantly decreased in both patients and controls. No differences in the melatonin level, growth hormone level, blood pressure, or pulse rate and no side effects were noted between patients and controls in the two study conditions; the timing of basal and 5-hydroxytryptophan-stimulated hormonal secretions was similar for both groups. These results are discussed with reference to current hypotheses of the cause of SAD.

5-Hydroxytryptophan↗
PubMed1987

Comparison of noninvasive breath hydrogen test for gastric acid secretion to standard intubation test in adults.

We have developed a noninvasive test for gastric acid secretion based on the reaction of ingested magnesium metal with gastric acid to produce hydrogen gas, which is excreted in exhaled air and belches. This test was compared to the standard intubation test by performing both, on different days, in 36 adult Peruvian outpatients referred for gastric analysis; the correlation coefficient for this comparison was 0.71. The new test was repeated in nine subjects, and the resulting test-retest correlation coefficient was 0.83. The new test thus compares favorably with the standard intubation test. Because it is also noninvasive and should therefore be more acceptable to subjects, this new test may be useful for clinical evaluation and research studies on subjects in whom intubation would be difficult or unacceptable.

Adult↗
PubMed1987

Comparison of noninvasive breath hydrogen test for gastric acid secretion to standard intubation test in infants and young children.

We have developed a noninvasive test of gastric acid secretion for use in infants and young children. It is based on the reaction of ingested magnesium metal with gastric acid to produce hydrogen gas, which is excreted in exhaled air and belches. This test was compared to the standard intubation test by performing both, on different days, in 20 children (5-37 months of age) without known gastric disease. The results of the two tests compared well: correlation coefficients were 0.78, 0.75, or 0.72 when exhaled air was collected for a total of 56, 81, or 31 min, respectively. Because the test is noninvasive, it should be more acceptable to children and their parents than the intubation test and thus could be used to conduct studies which are currently impractical.

Acute Disease↗
PubMed1987

The aetiology of diarrhoea in children at an urban hospital in Bangladesh.

Enteric pathogens were studied in 104 cases with acute diarrhoea and in 74 age and sex matched concurrent controls. One or more pathogens were isolated from 59.1% of cases compared with 20.4% of controls (P less than 0.001). Single enteropathogens were detected in 33.7% and multiple enteropathogens in 25.4% of the cases. Enteropathogenic Escherichia coli (EPEC), Campylobacter jejuni, rotavirus, Vibrio cholerae non-O1 and enterotoxigenic Escherichia coli were the major pathogens detected. The high rate of isolation of EPEC from diarrhoea cases (23.1%) indicated a definite role for this pathogen in causing endemic diarrhoea in Bangladesh.

Bangladesh↗
PubMed1987

Frequency analysis of the sleep EEG in depression.

Eight patients with major depressive disorder (seven bipolar and one unipolar) and matched controls had sleep studies, on which frequency analysis of the electroencephalogram (EEG) was performed. Total sleep and sleep efficiency were decreased in the patients, but there was no significant difference in rapid eye movement (REM) latency between the two groups. Frequency analysis revealed no group differences in power in the delta band (0.23-2.5 Hz) or the whole EEG spectrum (0.23-25 Hz). These findings suggest that mean REM latencies are not always shorter in major depression. The results are discussed in light of a previous report of decreased delta energy in the sleep EEG of unipolar patients.

Adult↗
PubMed1987

The effect of melatonin on normal sleep.

We examined the effect of 1-mg and 5-mg oral dosages of melatonin on the electroencephalogram-recorded sleep of ten normal subjects in a randomized, double-blind design. Although high dosages of melatonin have previously been reported to be a sedative and to have behavioral effects, we could not find any change in onset or duration of sleep, or any effect on mood or alertness the following day using these low dosages. An increase in rapid eye movement (REM) latency was noted at the 5-mg dose, but no other parameter of REM sleep was changed.

Adult↗
PubMed1987

B subunit-whole cell and whole cell-only oral vaccines against cholera: studies on reactogenicity and immunogenicity.

We conducted a randomized trial among persons in rural Bangladesh to evaluate the side effects and immunogenicity of orally administered B subunit-killed whole cell (BS-WC) and killed whole cell-only (WC) cholera vaccines and a killed Escherichia coli strain K12 placebo proposed for field testing. Three doses of BS-WC, WC, E. coli, or a control agent were given with antacid to 1,257 women (aged greater than 15 years) and children (aged to to 15 years). The four groups exhibited no statistically significant differences in occurrence of symptoms after each dose, and rises in titers of vibriocidal (VC) antibodies to Inaba and Ogawa were twofold higher for vaccinees than for controls (P less than .001). Half of the persons with fourfold or greater VC responses to WC responded after the first dose; many additional patients, particularly young children, responded after subsequent doses. In contrast, 89% of persons who responded to BS-WC with twofold or greater rises in titer of IgG antibodies to cholera toxin did so after the first dose. After the third dose, vaccinees exhibited a fivefold higher rise in titer than did controls (P less than .001); a dose-to-dose booster effect was most evident in young children.

Administration, Oral↗
PubMed1987

Rapid diagnosis of cholera by coagglutination test using 4-h fecal enrichment cultures.

A simple, rapid, and reliable method to detect Vibrio cholerae in fecal specimens would assist in the management of cases of severe diarrhea, especially since most such cases occur in areas with minimal laboratory facilities. A coagglutination test was used to detect V. cholerae antigen in bile-peptone broth incubated with feces. In the technique, Staphylococcus aureus Cowan 1 coated with anti-V. cholerae O1 antiserum was tested with cultures incubated for 4 h. When 165 specimens were tested, the sensitivity, specificity, and accuracy of the test, compared with standard culture methods, were 97, 99, and 98%, respectively. These promising results were better than those of dark-field microscopy using the same specimens, and the test was logistically easy to perform. The coagglutination test using enrichment broth culture of feces is a simple and rapid method which may be used to confirm a diagnosis of cholera.

Agglutination Tests↗
PubMed1987

Comparison of prophylactic tetracycline and clioquinol in a rabbit model of intestinal infection with Vibrio cholerae and Escherichia coli.

The ability of tetracycline and clioquinol to prevent intestinal colonization of Vibrio cholerae and Escherichia coli was tested in a rabbit model. In the model 10(10) bacteria are given via oro-gastric tube following intravenous cimetidine and oral sodium bicarbonate and prior to intraperitoneal tincture of opium. Eighteen hours after challenge the rabbits are sacrificed, and the numbers of the challenge strain remaining in the jejunum and ileum are determined. Tetracycline interrupted the intestinal colonization of V. cholerae and E. coli. Clioquinol however, had minimal effect on the colonization process. Our studies demonstrate the efficacy of prophylactic tetracycline but do not support the use of clioquinol to prevent intestinal infection due to these organisms. This rabbit model may also be useful to study the efficacy of other antibiotics against these bacterial infections.

Animals↗
PubMed1987

Morning versus midday phototherapy of seasonal affective disorder.

Sixteen depressed patients with seasonal affective disorder participated in a double-blind crossover study comparing the antidepressant effects of 2 hours of early morning and 2 hours of early afternoon therapy with bright light. They responded equally well to both treatments. These results suggest that the antidepressant effects of phototherapy in seasonal affective disorder do not depend on its capacity to extend day length (photoperiod) and are not likely to be due to a shift in the timing of circadian rhythms. These findings have practical implications for the administration of phototherapy in the treatment of seasonal affective disorder.

Circadian Rhythm↗
PubMed1987

Sleep reduction as a final common pathway in the genesis of mania.

Diverse psychological, interpersonal, environmental, and pharmacological factors that appear to trigger the onset of mania could act via their capacity to cause sleep deprivation, a mechanism that has been shown in experiments with bipolar patients to induce transient or sustained switches into mania. Since mania in turn causes insomnia, the development of mania is potentially self-reinforcing and could become autonomous after being initiated by precipitating factors. The sleep reduction model is based on experimental evidence and is a parsimonious explanation for the precipitation of manic episodes by a wide variety of factors. Furthermore, this model has clear implications for the prevention and treatment of mania and provides a conceptual focus and an experimental paradigm for psychological investigations of the causes of mania.

Adult↗
PubMed1987

Eye versus skin phototherapy of seasonal affective disorder.

In winter, depressed patients with seasonal affective disorder respond to treatment with bright artificial light (phototherapy). The authors found that the antidepressant effects of phototherapy were much greater for 10 patients when light was applied to the eyes than when it was applied to the skin, suggesting that its effects may be mediated by the eyes. The identification of a probable anatomical route of entry is clinically relevant and an important clue for further investigations of the mechanism of phototherapy. However, patients' expectations nearly always predicted the outcome, leaving open the possibility that expectations were responsible for their responses.

Attitude to Health↗
PubMed1987

Seasonal affective disorder: a review of the syndrome and its public health implications.

Seasonal affective disorder (SAD) is a disturbance of mood and behavior which resembles some seasonal changes seen in lower mammals. Like these animal seasonal changes, SAD is thought to be related to decreased sunlight during winter months. [SAD has been successfully treated with exposure to bright artificial light of higher intensity than is usually present in the home or workplace. Many people not suffering from SAD may nonetheless have seasonal changes which could be helped by environmental light supplementation. Lighting standards in the home and workplace should be re-evaluated on the basis of new knowledge of the psychobiological effects of light.] We review the literature on SAD and discuss its public health implications in the context of a typical case presentation.

Adult↗
PubMed1986

Field trial of oral cholera vaccines in Bangladesh.

The protective efficacy of oral B subunit killed whole-cell (BS-WC) and killed whole-cell (WC) cholera vaccines was assessed in 63 498 Bangladeshi children aged 2-15 years and women aged over 15 years. Each received three doses of BS-WC, WC, or placebo in a randomised, double-blinded fashion. Surveillance for cases seeking medical care up to six months after the third dose revealed 26 cases of confirmed cholera in the placebo group, 4 cases in the BS-WC group (protective efficacy 85%; p less than 0.0001), and 11 cases in the WC group (protective efficacy 58%; p less than 0.01). For each vaccine protective efficacy was consistent in different age-groups (2-10 years versus greater than 10 years) and for different severities of cholera.

Administration, Oral↗