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Biomedical subjects

L Tamarkin

Publications and source records attributed to L Tamarkin.

At least 19 recordsLinked to original sources
PubMed1991

Immunological correlates of seasonal fluctuations in mood and behavior and their relationship to phototherapy.

Immunological parameters were studied before and after phototherapy, with bright and dim light, in 38 individuals with a range of retrospectively reported seasonal changes in mood and behavior. There was a significant negative correlation between the degree of mood and behavioral difficulties in fall and winter (seasonality) and the total number of circulating natural killer cells. Changes in the numbers of circulating helper T cells correlated significantly with changes in mood following phototherapy. Moreover, mitogen-induced lymphocyte blastogenesis increased significantly after phototherapy, but there was no significant difference between the bright and dim light treatments. The results suggest that cellular immune function is associated with both seasonality and response to phototherapy.

Adult↗
PubMed1991

Sequential cerebrospinal fluid and plasma sampling in humans: 24-hour melatonin measurements in normal subjects and after peripheral sympathectomy.

Simultaneous measurements of plasma and cerebrospinal fluid (CSF) melatonin and urinary excretion of 6-hydroxymelatonin were performed in four normal volunteers and one patient before and after upper thoracic sympathectomy for the control of essential hyperhidrosis. For normal individuals, hourly 24-h melatonin concentrations in plasma and CSF exhibited similar profiles, with low levels during the day and high levels at night. Peak plasma levels varied from 122-660 pmol/L, and the peak CSF levels from 94-355 pmol/L. The onset of the nocturnal increase in melatonin did not occur at the same time for each individual. Urinary 6-hydroxymelatonin levels also exhibited a daily rhythm, with peak excretion at night. The individual with the lowest nocturnal levels of circulating melatonin also had the lowest excretion of 6-hydroxymelatonin. In the patient with hyperhidrosis, a prominent melatonin rhythm was observed preoperatively in the CSF and plasma. After bilateral T1-T2 ganglionectomy, however, melatonin levels were markedly reduced, and the diurnal rhythm was abolished. These results provide direct evidence in humans for a diurnal melatonin rhythm in CSF and plasma as well as regulation of this rhythm by sympathetic innervation.

Adult↗
PubMed1989

Melatonin profile in marmots: the influence of catecholamines, hibernation, and light.

The aim of this study was to determine the effects of circulating catecholamines and light on the daily melatonin rhythm in the marmot. Endogenous levels of circulating catecholamines and plasma melatonin were measured during arousal from hibernation in light and studies were performed on the circadian melatonin rhythm in two photoperiods (LD 4:20 and LD 8:16). In addition, studies were done on the capacity of broad-band white light at normal room intensities (32 muW/cm2 or 108 Ix) and of low-intensity monochromatic green light (500 nm; 1.4muW/cm2 or 3.1 Ix) to suppress high nocturnal melatonin levels. We conclude that high levels of plasma catecholamines that occur during arousal from hibernation do not influence the production and secretion of pineal melatonin. During the nocturnal portion of its light/dark cycle, the marmot plasma melatonin rhythm is suppressed by both white light and low-intensity green light.

Animals↗
PubMed1989

Ethanol enhancement of isoproterenol-stimulated melatonin and cyclic AMP release from cultured pineal glands.

Norepinephrine stimulates the synthesis of melatonin in the pineal gland. The action of norepinephrine is believed to be mediated primarily by beta adrenergic receptors, and involves activation of adenylate cyclase. Ethanol, 25 to 50 mM, added to cultured pineal glands in vitro, enhanced isoproterenol-induced stimulation of cyclic AMP and melatonin production. The action of ethanol was observed only at doses of isoproterenol that produced a submaximal effect, and ethanol alone had no effect on cyclic AMP or melatonin release. Butanol, at a concentration of 2 mM, was as effective as 50 mM ethanol in increasing isoproterenol-stimulated cyclic AMP and melatonin release, indicating that the response to alcohols was not due simply to changes in osmolarity, and may reflect a hydrophobic interaction of the alcohols with the cell membrane. The effects of ethanol on pineal cyclic AMP and melatonin release were reversible after a 15-min preincubation, but not after a 2-hr preincubation, suggesting that, over a long incubation period, ethanol may sensitize the pineal beta adrenergic receptor-coupled adenylate cyclase system to isoproterenol. The findings in this study are consistent with earlier work showing that ethanol increases cerebral cortical beta adrenergic receptor-coupled adenylate cyclase activity, and demonstrate that the effect of ethanol on the receptor-effector system can result in an endocrinological response.

1-Butanol↗
PubMed1989

Issues in psychoneuroimmunology research.

Careful design of studies is crucial for meaningful progress in this area of inquiry. Along with systematic evaluation of immunologic factors, clear understanding of antecedent factors is also important. Age, sex, and other sociodemographic factors might play a major role in how an individual reacts to a given situation when compared with another individual. Assessment of the impact of these factors on the immune system might be further complicated by immunosuppressive viruses like HIV or by the use of many common medications such as beta-blockers for hypertension (Kiecolt-Glaser & Glaser, 1988). Longitudinal studies are needed to understand the process of change and the dynamic patterning of psychosocial and immunologic relationships over time. Additionally, use of multimodal measures to assess psychological events such as stress is imperative (Baum, Grunberg, & Singer, 1982). It will not serve our understanding of psychological influences on the immune system to jump to the conclusion that an event is "stressful" because it seems as if it should be. Finally, establishing a "core" battery of widely accepted immune tests will be important in establishing comparability across studies. The standardization and acceptance of specific biochemical measures will facilitate the infusion of talented clinical and basic scientists into the area of psychoneuroimmunology.

Adaptation, Psychological↗
PubMed1988

Supersensitivity to melatonin suppression by light in young people at high risk for affective disorder. A preliminary report.

Affective illness aggregates in families and appears to be heritable. Bipolar affective patients have been found to be supersensitive to the suppressive effect of light on the nocturnal secretion of melatonin, both in ill and well states. We tested young people aged 15 to 25 years with one manic-depressive parent (n = 18), major affective disorder on both sides of the family (n = 7), and age-matched controls (n = 20). The subjects in the high-risk groups were more likely to show supersensitivity in melatonin response to light at night than controls. Follow-up studies are necessary to assess the predictive value of this response.

Adolescent↗
PubMed1988

The effect of total sleep deprivation on plasma melatonin and cortisol in healthy human volunteers.

Twelve healthy volunteers were included in this study. Baseline curves for melatonin and cortisol were obtained after one night of adaptation to laboratory conditions. From 10:00 p.m. to 6:00 a.m., blood samples were drawn every hour. On the third night, the subjects were kept awake at the sleep unit. Curves for the two hormones were then obtained after 36 h of total sleep deprivation (SD). The levels of these hormones were evaluated by calculating the area under the curve at each hour in both situations (basal and after sleep deprivation). It was found that the melatonin levels were increased after sleep deprivation, whereas the cortisol levels remained the same. These results suggest a mechanism by which a reset of abnormal rhythms can occur in depression.

Adolescent↗
PubMed1988

Chronic clorgyline treatment of Syrian hamsters: an analysis of effects on the circadian pacemaker.

Clorgyline, a type A monoamine oxidase inhibitor with antidepressant properties when administered to depressed patients, is often associated with disturbances of the human sleep-wake cycle. In order to assess its effects on the mammalian circadian system, this drug was administered chronically to Syrian hamsters. It was found to affect the hamster circadian system in four specific ways. Clorgyline increased the intrinsic period of wheel-running activity, altered the phase response curve to brief light pulses, altered the reduced waveform of running activity in animals maintained in light-dark cycles or constant darkness, and increased the activity-rest ratio in animals maintained in constant darkness. Our data support the interpretation that clorgyline exhibits direct or indirect input to the circadian pacemaker and alters the processing of photic information to the pacemaker.

Animals↗
PubMed1988

Interleukin-1 directly regulates hormone-dependent human breast cancer cell proliferation in vitro.

Direct in vitro effects of IL-1 on hormone-dependent (MCF-7 and ZR-75-B) and independent (HS-578-T and MDA-231) human breast cancer cell proliferation were investigated in short-term and long-term cell cultures. For short-term (48 h) studies [3H]thymidine uptake was used as an index of proliferation, while for long-term (12 day) cultures actual cell numbers were determined. Initial studies, conducted with MCF-7 cells, demonstrated that both forms of recombinant human IL-1 (alpha and beta) at 10(-11) M inhibited [3H]thymidine uptake by MCF-7 by 70%, and by day 7 of the long-term study alpha and beta IL-1 at 10(-11) M inhibited MCF-7 cell growth by 80%. IL-1, while inhibiting the growth of another hormone-dependent breast cancer cell line; ZR-75-B, had no effect on the hormone-independent cell lines MDA-231 and HS-578-T. The differing proliferative responses of the hormone-dependent and independent cells to IL-1 may, in part, be due to the expression of IL-1 receptors on these cells, in that MCF-7 cells express IL-1 receptors [dissociation constant (Kd) = 2.0 x 10(-10) M; receptor density = 2,500 sites per cell and mol wt = 80,000] while the hormone-independent MDA-231 cells do not.

Binding, Competitive↗
PubMed1987

Marked enhancement by clorgyline of nocturnal and daytime melatonin release in rhesus monkeys.

The type A monoamine oxidase (MAO)-inhibiting antidepressant clorgyline (1 mg/kg/24 days) administered to rhesus monkeys increased night-time cerebrospinal fluid (CSF) melatonin concentrations 3-fold and day-time maltonin values 5-fold. Other circadian parameters of melatonin release, including the peak time and duration of nocturnal melatonin elevation measured during continuous CSF collection periods of 90 min duration over 24-h cycles, were unaffected by clorgyline. While pinealocytes are thought to contain only MAO-B, treatment with the selective MAO-B inhibitor deprenyl (2 mg/kg/24 days) did not alter day or night-time melatonin concentrations. These results are consistent with MAO-A and non-selective MAO inhibitors acting via blockade of degradation of the preferential substrates of MAO-A, serotonin and/or norepinephrine, in adrenergic neurons entering the pineal gland. Further study is needed to evaluate the relative contributions of an increased availability of the melatonin precursor, serotonin, or a sustained net increase in alpha 1-or beta adrenoceptor-mediated input on pinealocytes to these marked changes in melatonin production.

Animals↗
PubMed1987

Differential response of rat splenic lymphocytes to short-term and long-term neuroendocrine challenges: possible desensitization of the cellular immune response to corticosteroids.

The effects of acute or chronic in vivo or in vitro exposures to supra-physiologic doses of isoproterenol, insulin or dexamethasone on rat splenic lymphocyte proliferation were investigated. Acutely, all in vivo challenges inhibited mitogen-induced lymphocyte proliferation, and correlated to increased corticosterone levels. However, chronic in vivo exposure to dexamethasone resulted in lymphocyte activity which was equivalent to controls, while chronic isoproterenol treatment enhanced the lymphocyte response to mitogen. These data suggest that chronic stress may result in a desensitization of the immune system to corticosteroids as well as a direct in vivo modulation by isoproterenol to enhance lymphocyte proliferation.

Adrenalectomy↗
PubMed1987

Treatment of a patient with seasonal premenstrual syndrome.

The authors identified a patient who had premenstrual syndrome (late luteal phase dysphoric disorder) only in the fall and winter and was virtually asymptomatic during the spring and summer. On the basis of previous experience with seasonal affective disorder, they treated the patient with bright artificial light, which reversed her symptoms. On subsequent occasions they reversed this treatment effect with oral melatonin administration and found that propranolol and atenolol, beta-antagonists that inhibit the production of melatonin, had a therapeutic effect similar to that of light. They discuss the implications of these findings in relation to the importance of melatonin as a mediator of seasonal rhythms in biology.

Adult↗
PubMed1987

Sex-differences in ethanol sensitivity and alcohol and aldehyde dehydrogenase activities in the Syrian hamster.

Because male Syrian hamsters demonstrate greater preference for ethanol than female hamsters, we compared them with regard to ethanol sensitivity and hepatic alcohol and aldehyde dehydrogenase activities. Male hamsters were slower to recover righting response and had lower blood alcohol levels upon recovery than did females. Hepatic alcohol dehydrogenase activity was approximately twice as high in females as males, but gender differences were not found for either cytosolic or non-cytosolic aldehyde dehydrogenase activities. The results suggest that the reduced ethanol sensitivity of female hamsters is due to more rapid metabolism. However, the finding that female hamsters have higher blood alcohol concentrations upon recovery also suggests the possibility of reduced CNS sensitivity.

Alcohol Dehydrogenase↗
PubMed1986

Pineal function during ethanol intoxication, dependence, and withdrawal.

Pineal melatonin and serotonin content were determined during one to four days of continuous intoxication, and during the alcohol withdrawal syndrome. The nocturnal rise in pineal melatonin was blunted in continuously intoxicated animals, however this was found to be unrelated to duration of treatment. The initial dependent-intoxicated phase of the alcohol withdrawal syndrome produced a reduction of nocturnal pineal melatonin content with a concomitant elevation in pineal serotonin. The overt withdrawal phase of the alcohol withdrawal syndrome had no effect on pineal melatonin or serotonin content. This data suggests that ethanol may perturb pineal melatonin synthesis either directly, or indirectly by altered receptor function. Contrary to our expectations the pineal may not be a useful model to probe the physiology of increased noradrenergic neurotransmission produced by ethanol withdrawal.

Alcohol Withdrawal Delirium↗
PubMed1986

Phototherapy of seasonal affective disorder. Time of day and suppression of melatonin are not critical for antidepressant effects.

Seasonal affective disorder is characterized by recurring cycles of fall-winter depression and spring-summer hypomania (or euthymia). In winter, depressed patients with seasonal affective disorder respond to daily treatments with five to six hours of bright artificial light in two to three days. They relapse two to three days after light is withdrawn. In this study carefully controlled experimental conditions were used to determine whether phototherapy acts via a photoperiodic mechanism in which the timing of light is critical for its therapeutic effect. Photoperiodism is a common regulatory mechanism in animal seasonal rhythms and depends for its effect on light-induced changes in the pattern of nocturnal melatonin secretion. The results reported herein of "skeleton photoperiod" experiments indicate that the efficacy of phototherapy may not depend on its timing or its effect on melatonin secretion.

Circadian Rhythm↗
PubMed1986

Human plasma melatonin is elevated during treatment with the monoamine oxidase inhibitors clorgyline and tranylcypromine but not deprenyl.

Melatonin was measured in plasma collected between 8:00 and 8:30 a.m. from 27 depressed patients studied before and after 21- to 24-day treatment with three monoamine oxidase (MAO) inhibitors. Baseline plasma melatonin concentrations determined by radioimmunoassay were 4.0 +/- SD 4.7 pg/ml. Tranylcypromine, a nonselective MAO inhibitor given in doses of 20-40 mg/day for 3 weeks, significantly elevated plasma melatonin to 10.6 +/- SD 2.0 pg/ml. Clorgyline, given in doses of 15-30 mg/day for 3 weeks, produced a significant, approximately three-fold increase in plasma melatonin (13.6 +/- SD 13.5 pg/ml). This clorgyline dose was selective for MAO type A inhibition, as MAO-B activity measured in platelets from the same blood samples was unaffected by clorgyline. In contrast, the selective MAO-B inhibitor deprenyl (10-30 mg/day for 3 weeks) led to a 96 +/- 4% inhibition of platelet MAO-B activity but no significant change in plasma melatonin (5.1 +/- SD 4.2 pg/ml). As both serotonin and norepinephrine are preferentially metabolized by MAO-A rather than MAO-B, an increased availability of serotonin (the precursor of melatonin) or enhanced noradrenergic function might mediate the melatonin changes observed to follow MAO-A but not MAO-B inhibition.

Blood Platelets↗