Salivary melatonin as a circadian phase marker: validation and comparison to plasma melatonin

There are many situations in which it would be useful to know the phase state of the biological clock. It is recognized that measurement of melatonin levels can provide this information, but traditionally blood has been used for the analysis, and there are many problems in extending the measurements into the home or field situations. The aim of this study was to develop and validate a salivary melatonin radioimmunoassay and to compare results obtained against a plasma assay for determining the onset of melatonin secretion. The assay developed was sensitive (4.3 pM) and required only 200 microliters of sample. A rhythm in melatonin was detected in saliva, peaking at approximately 120 pM or 30% of the plasma levels. Using an objective criterion for determining the onset of secretion (mean +/- 2 standard deviations of three daytime samples), the time of onset was shown to exhibit low intraindividual variability (coefficient of variation = 1.5%-4.3%). The time of onset determined using saliva was significantly correlated with the plasma onset (r = .70, p < .05). The onsets determined were 22:30 h +/- 22 min for the saliva and 21:50 h +/- 16 min for plasma for 17 subjects. Similarly, the acrophases of the saliva and plasma melatonin rhythms were significantly correlated. Neither posture alone nor changes in posture affected the calculation of the onset of melatonin secretion using the saliva approach. Very high saliva flow rates induced by citric acid resulted in lower melatonin concentrations compared to the gentle chewing on parafin film. These results firmly establish the use of salivary melatonin measurements for phase typing of the melatonin rhythm in humans.

A controlled trial of psychological treatment for the irritable bowel syndrome

One hundred two patients with irritable bowel syndrome were studied in a controlled trial of psychological treatment involving psychotherapy, relaxation, and standard medical treatment compared with standard medical treatment alone. Patients were only selected if their symptoms had not improved with standard medical treatment over the previous 6 months. At 3 months, the treatment group showed significantly greater improvement than the controls on both gastroenterologists' and patients' ratings of diarrhea and abdominal pain, but constipation changed little. Good prognostic factors included overt psychiatric symptoms and intermittent pain exacerbated by stress, whereas those with constant abdominal pain were helped little by this treatment. This study has demonstrated that psychological treatment is feasible and effective in two thirds of those patients with irritable bowel syndrome who do not respond to standard medical treatment.

Microduplication 22q11.2, an emerging syndrome: clinical, cytogenetic, and molecular analysis of thirteen patients

Chromosome 22, particularly band 22q11.2, is predisposed to rearrangements due to misalignments of low-copy repeats (LCRs). DiGeorge/velocardiofacial syndrome (DG/VCFS) is a common disorder resulting from microdeletion within the same band. Although both deletion and duplication are expected to occur in equal proportions as reciprocal events caused by LCR-mediated rearrangements, very few microduplications have been identified. We have identified 13 cases of microduplication 22q11.2, primarily by interphase fluorescence in situ hybridization (FISH). The size of the duplications, determined by FISH probes from bacterial artificial chromosomes and P(1) artificial chromosomes, range from 3-4 Mb to 6 Mb, and the exchange points seem to involve an LCR. Molecular analysis based on 15 short tandem repeats confirmed the size of the duplications and indicated that at least 1 of 15 loci has three alleles present. The patients' phenotypes ranged from mild to severe, sharing a tendency for velopharyngeal insufficiency with DG/VCFS but having other distinctive characteristics, as well. Although the present series of patients was ascertained because of some overlapping features with DG/VCF syndromes, the microduplication of 22q11.2 appears to be a new syndrome.

Behavior and neurocognitive performance in children aged 5-10 years who snore compared to controls

Sleep disordered breathing in children is a common but largely underdiagnosed problem. It ranges in severity from primary snoring to obstructive sleep apnea syndrome (OSAS). Preliminary evidence suggests that children with severe OSAS show reduced neurocognitive performance, however, less is known about children who snore but do not have severe upper airway obstruction. Participants included 16 children referred to the Ear, Nose and Throat/Respiratory departments of a Children's Hospital for evaluation of snoring and 16 non-snoring controls aged 5-10 years. Overnight polysomnography (PSG) was carried out in 13 children who snored and 13 controls. The PSG confirmed the presence of primary snoring in seven and very mild OSAS (as evidenced by chest wall paradox) in eight children referred for snoring while controls showed a normal sleep pattern. To test for group differences in neurocognitive functioning and behavior, children underwent one day of testing during which measures of intelligence, memory, attention, social competency, and problematic behavior were collected. Compared to controls, children who snored showed significantly impaired attention and, although within the normal range, lower memory and intelligence scores. No significant group differences were observed for social competency and problematic behavior. These findings suggest that neurocognitive performance is reduced in children who snore but are otherwise healthy and who do not have severe OSAS. They further imply that the impact of mild sleep disordered breathing on daytime functioning may be more significant than previously realized with subsequent implications for successful academic and developmental progress.

Melatonin and sleep in humans

Early studies on the physiological effects of melatonin typically reported hypnotic 'side-effects'. Later studies, specifically addressing this action, failed to reliably replicate hypnotic effects using standard polysomnography. This difference may be related to differences in the basic physiological action of melatonin compared with more conventional hypnotics. It is suggested that melatonin exerts a hypnotic effect through thermoregulatory mechanisms. By lowering core body temperature, melatonin reduces arousal and increases sleep-propensity. Thus, in humans, one role of melatonin is to transduce the light-dark cycle and define a window-of-opportunity in which sleep-propensity is enhanced. As such, melatonin is likely to be an effective hypnotic agent for sleep disruption associated with elevated temperature due to low circulating melatonin levels. The combined circadian and hypnotic effects of melatonin suggest a synergistic action in the treatment of sleep disorders related to the inappropriate timing of sleep and wakefulness. Adjuvant melatonin may also improve sleep disruption caused by drugs known to alter normal melatonin production (e.g., beta-blockers and benzodiazepines). If melatonin is to be developed as a successful clinical treatment, differences between the pharmacological profile following exogenous administration and the normal endogenous rhythm should be minimized. Continued development as a useful clinical tool requires control of both the amplitude and duration of the exogenous melatonin pulse. There is a need to develop novel drug delivery systems that can reliably produce a square-wave pulse of melatonin at physiological levels for 8-10 hr duration.

Primary body cavity-based AIDS-related lymphomas

Five patients with advanced AIDS developed a unique type of high grade primary body cavity-based non-Hodgkin's lymphoma (NHL). The lymphomas were exclusively in serous effusions with no detectable mass disease in the body cavities and no lymphadenopathy or organomegaly. All of the lymphomas exhibited virtually identical morphology, which could not be precisely classified, but appeared to bridge features of large cell immunoblastic and anaplastic large cell lymphomas. Immunophenotypically the lymphoma cells lacked expression of any B- or T-lymphocyte antigens, but expressed CD45 and the activation antigens CD30, CD38, CD71, and HLA-DR. Clonally rearranged immunoglobulin heavy chain and kappa light chain genes were identified by Southern blot analysis. Molecular studies also revealed Epstein-Barr virus (EBV) and Kaposi's sarcoma-associated herpesvirus (KSHV) genomes and germline configuration of the c-myc protooncogene. In two cases studied cytogenetically, the lymphoma cells manifested complex chromosome abnormalities. These lymphomas are clinically and biologically unique and found predominantly in patients with advanced AIDS, in many cases with pre-existing Kaposi's sarcoma.

Alleviation of sleep maintenance insomnia with timed exposure to bright light

OBJECTIVE

Half of the population over 65 suffers from chronic sleep disturbance. As a consequence, almost 40% of hypnotic medications are prescribed to people over age 60. Yet, hypnotics are often of little benefit in this population. As such, an effective non-drug alternative could prove important in the management of age-related sleep maintenance insomnia. The current study sought to evaluate the efficacy of bright light exposure in the treatment of sleep maintenance insomnia.

DESIGN

Following baseline sleep and circadian rhythms assessment, subjects with sleep-maintenance insomnia were treated with timed exposure to either bright white light or dim red light for 12 consecutive days. Sleep and circadian rhythms recordings were subsequently obtained and measures of sleep quality were compared to assess efficacy of the treatments.

SETTING

Baseline and post-treatment sleep and circadian rhythms assessments took place in the Laboratory of Human Chronobiology, Department of Psychiatry, Cornell University Medical College. The treatment phase of the study was conducted in participants' homes.

PARTICIPANTS

Sixteen men and women between the ages of 62 and 81 years were studied. All subjects were free of hypnotic medication, and all had experienced sleep disturbance for at least 1 year prior to entering the study.

RESULTS

Exposure to bright light resulted in substantial changes in sleep quality. Waking time within sleep was reduced by an hour, and sleep efficiency improved from 77.5% to 90%, without altering time spent in bed. Increased sleep time was in the form of Stage 2 sleep, REM sleep, and slow wave sleep. The effects were remarkably consistent across subjects.

CONCLUSIONS

The findings demonstrate the effectiveness of timed exposure to bright light in the treatment of age-related sleep maintenance insomnia. With further refinement of treatment regimens, this non-drug intervention may prove useful in a large proportion of sleep disturbed elderly.

Skeletal muscle microvascular recruitment by physiological hyperinsulinemia precedes increases in total blood flow

Supraphysiological doses of insulin enhance total limb blood flow and recruit capillaries in skeletal muscle. Whether these processes change in response to physiological hyperinsulinemia is uncertain. To examine this, we infused either saline (n = 6) or insulin (euglycemic clamp, 3.0 mU x min(-1) x kg(-1), n = 9) into anesthetized rats for 120 min. Femoral artery flow was monitored continuously using a Doppler flow probe, and muscle microvascular recruitment was assessed by metabolism of infused 1-methylxanthine (1-MX) and by contrast-enhanced ultrasound (CEU). Insulin infusion raised plasma insulin concentrations by approximately 10-fold. Compared with saline, physiological hyperinsulinemia increased femoral artery flow (1.02 +/- 0.10 vs. 0.68 +/- 0.09 ml/min; P < 0.05), microvascular recruitment (measured by 1-MX metabolism [6.6 +/- 0.5 vs. 4.5 +/- 0.48 nmol/min; P < 0.05] as well as by CEU [167.0 +/- 39.8 vs. 28.2 +/- 13.8%; P < 0.01]), and microvascular flow velocity (beta, 0.14 +/- 0.02 vs. 0.09 +/- 0.02 s(-1)). Subsequently, we studied the time dependency of insulin's vascular action in a second group (n = 5) of animals. Using CEU, microvascular volume was measured at 0, 30, and 90 min of insulin infusion. Insulin augmented microvascular perfusion within 30 min (52.8 +/- 14.8%), and this persisted at 90 min (64.6 +/- 9.9%). Microvascular recruitment occurred without changes to femoral artery flow or beta. We conclude that insulin increases tissue perfusion by recruiting microvascular beds, and at physiological concentrations this precedes increases in total muscle blood flow by 60-90 min.

Development and Validation of a Scale to Measure Work-Related Fatigue and Recovery: The Occupational Fatigue Exhaustion/Recovery Scale (OFER)

OBJECTIVE

Various empirical studies link persistent failure to recover from acute fatigue to the evolution of chronic fatigue. However, existing fatigue measurement scales do not tend to distinguish between acute and chronic fatigue elements well, and none include a measure of effective recovery from fatigue.

METHODS

The 15 item Occupational Fatigue Exhaustion Recovery (OFER) scale has been developed and validated in three study populations specifically to measure work-related fatigue.

RESULTS

The OFER scale possesses robust, gender-bias free psychometric characteristics. Its three subscales identify and distinguish between chronic work-related fatigue traits, acute end-of-shift states and effective fatigue recovery between shifts.

CONCLUSION

These studies confirm the mediating role of intershift-shift recovery in the evolution of adaptive end-of-shift fatigue states to maladaptive persistent fatigue traits. The OFER scale is suggested as a potentially valuable new tool for use in work-related fatigue research.

Liver transplant-associated graft-versus-host disease

BACKGROUND

Graft-versus-host disease (GVHD) is an important, underdiagnosed cause of mortality associated with liver transplantation. We identified 12 cases of GVHD among 1,082 liver transplantations performed in patients at our institution between 1991 and 1998. Patients typically developed fever, skin rash, diarrhea, or pancytopenia within 2 to 6 weeks after their transplant. Treatment generally involved increased immune suppression and hematopoietic cytokines (granulocyte colony stimulating factor, granulocyte monocyte colony stimulating factor); however, all but one patient died, most often from sepsis. Early in its course, GVHD was difficult to distinguish from cytomegalovirus disease or drug reactions. The diagnosis was confirmed by demonstration of substantial donor lymphoid chimerism.

METHODS

To identify risk factors for severe GVHD, a retrospective analysis was performed comparing index cases with the rest of the cases in our institutional experience.

RESULTS

Closely matched human leukocyte antigen recipients, those older than 65 years, and recipients with donors more than 40 years younger were at higher risk for GVHD. One case occurred in a patient with a congenital immunodeficiency.

CONCLUSIONS

Liver transplant-associated GVHD is a progressive and fatal disease. Future approaches should focus on prevention and might include avoidance of closely matched human leukocyte antigen donors, treatment of the donor to reduce the number of lymphocytes, or reduction of immunosuppression in the early posttransplant period.

Polyclonal Mycobacterium avium complex infections in patients with nodular bronchiectasis

Mycobacterium avium complex (MAC) isolates among patients with chronic lung disease were studied for their heterogeneity using genetic identification methods, pulsed field gel electrophoresis (PFGE) and seroagglutination. A mean of 7.3 cultures per patient were collected from 17 patients with nodular bronchiectasis who were elderly (mean age 66 yr), predominantly female (76%), had smoked a mean of only 5 pack-years, and had multifocal bronchiectasis. A mean of 7.7 cultures per patient were collected from nine patients with upper lobe cavitary disease who were younger (mean age 52 yr), predominantly male (78%), and heavy smokers (mean 56 pack-yr). A mean of 2.9 PFGE types (genotypes) per patient (range, 1 to 9) were identified in the nodular bronchiectasis group, with 15 of 17 patients (88%) having two or more genotypes and 9 of 17 (53%) having three or more genotypes. In contrast a mean of 1.2 genotypes were identified in the patients with cavitary disease, with only 1 of 9 (11%) having two or more genotypes. Mycobacterium intracellulare was the most frequently recovered genotype in both groups and most isolates were rough or nontypable by seroagglutination. Some genotypes from the same patient considered different by current PFGE criteria had the same serotype and shared 11 to 20 common PFGE bands, suggesting they were related. These data demonstrate that patients with nodular bronchiectasis have multiple and/or repeated infections due to MAC whereas patients with upper lobe cavitary disease are usually infected with only a single strain.

Improving adaptation to simulated night shift: timed exposure to bright light versus daytime melatonin administration

Chronic circadian disturbance is thought to cause many of the health and social problems reported by shift workers. In recent years, appropriately timed exposure to bright light and exogenous melatonin have been used to accelerate adaptation to phase shifts of the circadian system. In this study we compared adaptation to night shift in three groups of subjects. The first treatment group received timed exposure to bright light (4-7,000 lux between 2400 and 0400 hours on each of three night shifts). The second treatment group received exogenous melatonin by capsule (2 mg at 0800 hours then 1 mg at 1100 and 1400 hours). The placebo control groups received either dim red light at less than 50 lux or placebo (sucrose) in identical capsules at the same time. Results indicated that all groups shifted significantly from baseline. Using the dim-light melatonin onset as a circadian marker, the bright-light group shifted the furthest, whereas there was no significant difference between the melatonin and placebo groups. Sleep quality as determined by wrist actigraphy was most improved in the light-treatment group, although the melatonin group also showed significant improvements. Cognitive psychomotor performance was most improved in the light-treatment group and the melatonin group again showed little difference from the control group. Although melatonin was unable to increase the amount of the phase shift following transition to night shift, it is likely that the intermediate levels of improvement in sleep reflect the hypothermic effects of melatonin. By lowering core temperature across the sleep period, sleep may be enhanced. This improvement in sleep quality did not produce concomitant improvements in shift performance for the melatonin group. This suggests that the enhanced performance in the light-treatment group may reflect more direct "energizing" effects. On the basis of these results, bright light is clearly superior in its ability ot phase shift the circadian system and thereby improve sleep and performance. However, melatonin may permit shift workers to override the circadian system for short periods and avoid the potential toxicity due to overzealous manipulations of the circadian pacemaker. In rapidly rotating shift schedules, melatonin may be preferable because it would not require workers to reverse the large phase shift induced by light.

Targeting of marrow-derived astrocytes to the ischemic brain

Bone marrow progenitor cells have been shown to contribute to a small proportion of cells in nonhematopoietic tissues including the brain. In the acute unilateral middle cerebral artery occlusion model in spontaneously hypertensive rats following male-to-female bone marrow transplantation, we present data suggesting that 55% more marrow-derived cells, in general, and 161% more GFAP-positive astrocytes, in particular, migrate preferentially to the ischemic cortex than to the contralateral non-ischemic hemisphere. In addition to their biological significance, our findings could have therapeutic implications. Marrow-derived progenitor cells could potentially be used as vehicles for ex vivo gene transfer to the brain.

Quantifying the performance impairment associated with fatigue

The present study systematically compared the effects of fatigue and alcohol intoxication on a range of neurobehavioural tasks. By doing so, it was possible to quantify the performance impairment associated with fatigue and express it as a blood alcohol impairment equivalent. Twenty-two healthy subjects aged 19-26 years participated in three counterbalanced conditions. In the sustained wakefulness condition, subjects were kept awake for 28 h. In the alcohol and placebo conditions, subjects consumed either an alcoholic or non-alcoholic beverage at 30 min intervals, until their blood alcohol concentration reached 0.10%. In each session, performance was measured at hourly intervals using four tasks from a standardised computer-based test battery. Analysis indicated that the placebo beverage did not significantly effect mean relative performance. In contrast, as blood alcohol concentration increased performance on all the tasks, except for one, significantly decreased. Similarly, as hours of wakefulness increased performance levels for four of the six parameters significantly decreased. More importantly, equating the performance impairment in the two conditions indicated that, depending on the task measured, approximately 20-25 h of wakefulness produced performance decrements equivalent to those observed at a blood alcohol concentration (BAC) of 0.10%. Overall, these results suggest that moderate levels of fatigue produce performance equivalent to or greater than those observed at levels of alcohol intoxication deemed unacceptable when driving, working and/or operating dangerous equipment.

Sleep disruption and mood changes associated with menopause

This study examined the sleep and mood differences between premenopausal and perimenopausal women matched for age and sociodemographic variables. Wrist actigraphy, Profile of Mood State (POMS), State-Trait Anxiety Inventory (STAI), a sleep questionnaire, and responses to a sleep diary were recorded for a period of 1 week. It was found that the sleep disruption of perimenopausal subjects was significantly greater than that of the premenopausal group (p < 0.05). Overall, the perimenopausal group demonstrated a significant increase in sleep disruption and mood alterations when compared with the premenopausal group. Actigraphic data showed that perimenopausal subjects experienced longer and more numerous arousals resulting in significantly less sleep (p < 0.05). In addition, perimenopausal subjects scored significantly higher (p < 0.05) on the STAI and significantly lower on the Vigor subscale of the POMS (p < 0.01) than premenopausal subjects. Correlational analyses indicated that sleep and mood changes were significantly related in the perimenopausal group, but not in the premenopausal group. Taken together, these results suggest that the mood changes experienced by the perimenopausal group may be mediated by sleep disruption.

Enhancement of nighttime alertness and performance with bright ambient light

Objective levels of alertness and performance efficiency were measured in twenty-five healthy young adults during two simulated night shifts. Following the first night shift, during which all subjects worked under dim ambient light (10-20 lux), subjects were assigned to one of three ambient lighting conditions (10-20 lux, 100 lux or 1000 lux) for the second night of work. Subjects exposed to 1000 lux ambient light maintained significantly higher levels of alertness across the 8-hour shift than did subjects exposed to the dimmer lighting conditions. Cognitive performance was also significantly enhanced under the bright light condition, whereas simple reaction time was not. The findings indicate clearly that ambient lighting levels can have a substantial impact on nighttime alertness and performance and that bright ambient illumination may be effective in maintaining optimal levels of alertness during night shift operations.

Timed exposure to bright light improves sleep and alertness during simulated night shifts

Many of the health and safety problems reported by shift workers result from the chronic sleep deprivation associated with shorter, fragmented daytime sleep. This reduction in the quality and duration of sleep has been attributed to a change in the phase relationship between the work period and the circadian system, timing the propensity for sleep and wakefulness. This study examined the extent to which appropriately timed exposure to bright light would accelerate the circadian readjustment of physiological parameters thought to contribute to impaired performance in shift workers. A control (n = 7) and treatment group (n = 6) underwent a 3-day transition to simulated night work. The treatment group received a single 4-hour pulse of bright light (6,000 lux) between 2400 and 0400 hours on the first night shift and dim light (less than 200 lux) for the remainder of the study. The control group received dim light throughout. By the third night shift, the phase position of the core body temperature rhythm for the treatment group had delayed by 5-6 hours whereas the control group had delayed by only 2-3 hours. When compared to the control group, the greater delay in core temperature rhythm for the treatment group was associated with significantly higher alertness across the night shift and improved sleep quality during the day. By the third day sleep, mean sleep efficiency in the treatment group was not significantly different from normal night sleep. Similarly, onshift alertness was improved relative to the control group. The treatment group did not show the typical decline in alertness observed in the control group between 0300 and 0700 hours. These data indicate that a single 4-hour pulse of bright light between midnight and 0400 hours is effective in ameliorating the sleep and alertness problems associated with transition to night shift.

Reduced signal intensity on MR images of thalamus and putamen in multiple sclerosis: increased iron content?

High-field-strength (1.5-T) MR imaging was used to evaluate 47 patients with definite multiple sclerosis and 42 neurologically normal control patients. Abnormal, multiple foci of increased signal intensity on T2-weighted images, most prominent in the periventricular white matter, were apparent in 43 of 47 MS patients and in two of 42 control patients. A previously undescribed finding of relatively decreased signal intensity most evident in the putamen and thalamus on T2-weighted images was seen in 25 of 42 MS patients and correlated with the degree of white-matter abnormality. In the normal control patients a prominently decreased signal intensity was noted in the globus pallidus, as compared with the putamen or thalamus, correlating closely with the distribution of ferric iron as determined in normal Perls'-stained autopsy brains. The decreased signal intensity (decreased T2) is due to ferritin, which causes local magnetic field inhomogeneities and is proportional to the square of the field strength. The decreased T2 in the thalamus and striatum in MS may be related to abnormally increased iron accumulation in these locales with the underlying mechanism remaining speculative.

Should alcohol consumption measures be adjusted for gender differences?

Because of biological differences between men and women, the same quantity of alcohol consumed over the same time period produces higher blood alcohol levels (BALs) in women than in men. Some alcohol researchers have proposed that quantity and volume measures of alcohol consumption (e.g. usual number of drinks per drinking day and overall amount of alcohol consumed) should be adjusted to reflect these biological differences. To date, no standard adjustment for biological gender differences has been adopted. In this paper, we review the literature on biological and behavioral differences related to alcohol consumption and effects and discuss the implications of these differences in terms of adjusting alcohol consumption measures. Our review suggests that adjusting measures of alcohol consumption to compensate for biological sex differences is most appropriate for research or policy applications involving the short and long-term physiological effects of alcohol in contexts where gender differences in how alcohol is consumed can be assumed to be minimal. In other circumstances, non-biological gender differences relating to alcohol use, such as pace of drinking, may moderate the relationship between alcohol consumption and biological gender differences, making an adjustment less defensible. We also identify areas where more knowledge is needed not only to address the issue of adjusting alcohol measures for gender differences but also to understand better the relationship between alcohol consumption and effects.

Chronobiotics--drugs that shift rhythms

A chronobiotic is defined and levels of action within the mammalian circadian pacemaker system, such as the retina, retinohypothalamic tract, geniculohypothalamic tract, suprachiasmatic nuclei, output and feedback systems are identified. Classes of drug that include the indoleamines, cholinergic agents, peptides, and benzodiazepines, which might act as chronobiotics within these levels, are evaluated. Particular emphasis is placed on the indole, melatonin (MLT). The clinical circumstances for use of chronobiotics in sleep disturbances of the circadian kind, such as jet lag, shift work, delayed sleep-phase syndrome, advanced sleep-phase syndrome, irregular and non-24-hr sleep-wake cycles, are described under reorganized headings of disorders of entrainment, partial entrainment, and desynchronization. Specific attention is given to the blind and the aged. Both human and animal studies suggest that MLT has powerful chronobiotic properties. MLT shows considerable promise as a prophylactic and therapeutic alternative or supplement to the use of natural and artificial bright light for resetting the circadian pacemaker. Throughout this discussion, the hypnotic and hypothermic versus the chronobiotic actions of MLT are raised. Finally, problems in the design of delivery systems for MLT are discussed.

Urinary 6-sulfatoxymelatonin excretion and aging: new results and a critical review of the literature

The apparent age-related decline in melatonin production has been thought to continue in a secular manner across the lifespan. While it is clear that melatonin levels in children and adolescents are elevated compared to older individuals, the question of whether there is a sudden or gradual change has not been adequately addressed. In this study, we report the excretion of the melatonin metabolite, 6-sulfatoxymelatonin in 253 subjects aged between 21 and 82 yr. The correlation with age was significant (r = -0.24; P < 0.05). When the data was analysed by ANOVA using 5-yr age spans, there was a significant effect of age, but post hoc analysis indicated that after 25 yr of age there was no significant decline in excretion of the metabolite. Thus, although the oldest subjects excreted 36% less melatonin metabolite than the youngest, the decrease occurred at a very early age. In the second part of the study, we re-evaluated the data from seven previous studies that measured plasma melatonin levels or metabolite excretion across a wide range of ages and 11 studies comparing young versus older subjects. Statistical analysis by ANOVA again suggested that the changes in melatonin occurring with age were essentially complete before 30 yr of age. The youngest subjects produced at the most twice the amount of melatonin as the oldest subjects. Finally, we evaluated the mean plasma melatonin levels in 144 groups of normal subjects reported in 137 separate publications with respect to age. Again, whereas there was a significant correlation with age, ANOVA showed that there was no difference between groups after 35 yr of age, and the oldest groups had levels that were only 43% of the youngest groups. We conclude that melatonin production is lower in older people, but that the change occurs very early in life, around 20-30 yr of age.

Intracerebral hemorrhage and oral amphetamine

Four patients suffered intracerebral hemorrhages following the oral or nasal use of amphetamine or related compounds. Two of these patients had abnormal-appearing cerebral blood vessels on angiography. Review of previously reported cases showed that intracerebral hemorrhage may occur in patients using the drug for the first time and for nonrecreational purposes.

Immunophenotypic analysis of peripheral T-cell neoplasms. A multiparameter flow cytometric approach

We retrospectively reviewed multiparameter flow cytometric analyses in 50 peripheral T-cell neoplasms (PTCNs). Results were interpreted within the context of a large cohort of nonneoplastic T-cell populations. All PTCN diagnoses were confirmed with morphologic and/or molecular analysis. Aberrant populations were defined as discrete immunophenotypic clusters exhibiting loss of or increased or diminished expression of T-cell antigens relative to internal immunophenotypically normal T-cell populations. An antigenic pattern was considered abnormal if it exceeded ranges for T-cell subsets in specific anatomic sites or was not normally encountered. Forty-six of 50 and 41 of 50 demonstrated 1 or more and 2 or more aberrations, respectively. The most common abnormally expressed antigen was CD3, followed by CD7, CD5, and CD2. Except for CD7, abnormally dim or bright antigen expression was more common than deletion. Only 3 cases were abnormal solely based on expansion of an otherwise immunophenotypically normal population; the remainder had patterns of antigen expression not seen in nonneoplastic populations. These data indicate that most PTCNs are aberrant by multiparameter flow analysis. However, results must be interpreted within the context of thorough knowledge of the immunophenotypic spectrum of nonneoplastic T cells.

Quantitative polymerase chain reaction for human herpesvirus diagnosis and measurement of Epstein–Barr virus burden in posttransplant lymphoproliferative disorder

Human herpesviruses can cause acute diseases such as chicken pox or mononucleosis, but also may reactivate during immunosuppression and result in severe or life-threatening illnesses such as shingles or lymphoproliferative disorders. We report the development and validation of a quantitative PCR method to measure viral burden for all eight human herpesviruses (HSV1, HSV2, VZV, EBV, CMV, HHV6, HHV7, and KSHV) in patients’ samples. The method uses an internal standard that is coamplified with the viral target, allowing quantification of viral genomes in absolute terms (e.g., viral targets/mL of blood) and ruling out false-negative results. We demonstrate that transplant patients with lymphoproliferative disorder carry an EBV viral burden 3 logs higher than nontransplant patients. EBV titers in transplant patients without a lymphoproliferative disorder are between these values. This quantitative PCR method may aid in differentiating clinically significant vs latent viral burden in immunosuppressed patients.