Search PubMed⌕ Search

Biomedical subjects

M Irwin

Publications and source records attributed to M Irwin.

At least 37 records · Page 2Linked to original sources
PubMed2000

Effect of the intensity of wireless telephone conversations on reaction time in a braking response.

Recently, concern has grown about the extent to which wireless telephone use by motor vehicle drivers constitutes a threat to traffic safety. This experiment investigated the effect of the intensity of wireless telephone conversations on reaction time (RT) for a braking response. Using a laboratory station to mimic the foot activity in driving, 16 adults were instructed to release the accelerator pedal and depress the brake pedal as quickly as possible following the activation of a red brake light. Mean RT was measured for 5 conditions which manipulated the intensity of a conversation, i.e., demand for attention, conducted on a wireless telephone. Analysis indicated that wireless telephone use caused a decrement in RT, however, there was no significant effect associated with intensity of the conversation across intensity.

Accidents, Traffic↗
PubMed2000

Decreased natural killer cell responses and altered interleukin-6 and interleukin-10 production in alcoholism: an interaction between alcohol dependence and African-American ethnicity.

BACKGROUND: Epidemiological data indicate that among alcoholics African-American men have higher rates of infections compared with white alcoholics. Alcohol is thought to reduce natural killer (NK) cell responses and to alter cellular immunity by changing the relative balance of Th1 versus Th2 cytokine response profiles. However, translation of these basic immunological observations into the clinical setting is limited, and what clinical data are available are contradictory, in part, because of heterogeneity within the alcoholic patient population. Whether ethnic characteristics contribute to variation in the immunological effects of alcohol is not known. METHODS: This study compared NK activity, interleukin (IL)-2-stimulated NK activity, and concanavalin A-stimulated peripheral blood mononuclear cell production of Th1 (IL-12 and IL-2), Th2 (IL-10), and proinflammatory (IL-6) cytokines in 31 hospitalized chronic alcoholic patients and 31 age-matched controls who were stratified on the basis of ethnicity. RESULTS: NK-cell responses were significantly different across the four groups, and African-American alcoholics showed the lowest levels of NK activity (F = 9.5;p < 0.001) and IL-2-stimulated NK activity (F = 2.9; p < 0.05). Compared with the other three groups, African-American alcoholics also showed lower levels of IL-6 (F = 7.2;p < 0.01) and higher levels of IL-10 (F = 4.9;p < 0.05). Stimulated production of IL-2 and IL-12 were similar in the four groups. Regression analyses showed that alcohol dependence and ethnicity predicted NK activity, whereas the interaction between alcohol dependence and ethnicity predicted levels of IL-6 and IL-10. CONCLUSIONS: In summary, the immunological effects of alcohol dependence are modified by ethnicity status, consistent with the increased health risks found in African-American alcoholics.

Adult↗
PubMed2000

Polysomnographic and spectral sleep EEG in primary alcoholics: an interaction between alcohol dependence and African-American ethnicity.

BACKGROUND: Disturbances of sleep EEG are prominent in alcoholic patients, persist into recovery, and recently have been found to predict those alcoholics who are most likely to relapse. Increasing evidence indicates that there are ethnic differences in sleep EEG and that African-Americans may be at elevated risk for disordered sleep. METHODS: This study compared polysomnographic and spectral sleep EEG measures in male primary alcoholic inpatients (n = 31) and age-matched comparison controls (n = 31) stratified by African-American and Euro-American ethnicity. RESULTS: African-American alcoholic patients showed more severe sleep abnormalities than Euro-American alcoholics, and the interaction between alcohol dependence and ethnicity uniquely contributed to prolonged sleep latency (p < 0.001), loss of delta sleep (p < 0.001), and short rapid eye movement (REM) latency (p < 0.001). Spectral EEG analyses confirmed polysomnographic findings of disordered sleep architecture in alcoholics. Compared with controls, alcoholics had lower delta (0.75-4.5 Hz) activity over the whole night (p < 0.05), reductions in mean spectral power (0.75-40 Hz, p < 0.05), and decreases of delta (p < 0.01) and theta (4.5-7.5 Hz,p = 0.05) activity during the first period of non-REM sleep, with African-American alcoholics having the lowest theta of the four groups. CONCLUSIONS: In view of the possible connection between relapse and poor sleep and the role of sleep in the maintenance of health, these data have implications for treatment and morbidity outcomes in African-American alcoholics.

Adult↗
PubMed1999

Immune correlates of depression.

The relation of depression to immunological assays is complex and variable. However, meta-analyses have demonstrated that depressed subjects are likely to show changes in several immune assays. Depressed subjects are likely to have changes in major immune cell classes with an increase in total white blood cell counts and a relative increase in numbers of neutrophils. However, the relative number of lymphocytes is likely to be reduced in depressed subjects. Depression also appears to be associated with increases in at least one measure of immune activation, although further investigations are clearly needed to replicate these interesting observations. Finally, depression is reliably associated with a suppression of mitogen-induced lymphocyte proliferation and with a reduction of NK activity. Despite the heterogeneity of findings, the effect sizes in the relationship between depression and lymphocyte proliferation and NK activity are large as compared to those observed in other areas of psychological and medical research. Several moderating factors may explain and account for the heterogeneity that has been found in the depression-immune results. Future immunologic studies in depressed subjects are needed to clarify the effects of gender and reproductive hormones on the relation between depression and immunity. Severity of melancholic symptoms and sleep disturbance appear to moderate the immune changes in depression but the biological mechanisms that account for the link between these neurovegetative symptoms and depression are not yet known. Finally, assessment of co-morbidity in depressed subjects deserves an increased focus. Data generated from our laboratory clearly show that assessment of alcohol- and tobacco dependence is critical in the interpretation of immune changes in depressed subjects. The clinical significance of changes in immune responses in depressed subjects remains an unanswered question. Studies that use immune measures with disease specific endpoints, as has been recently conducted in the study of VZV immune responses, would help identify the possible link between depression, immune system alterations, and health outcomes.

Chickenpox↗
PubMed1999

Pregnancy-related mortality in Hispanic women in the United States.

OBJECTIVE: To examine pregnancy-related mortality among Hispanic women in the United States. METHODS: We used data from the Centers for Disease Control and Prevention's ongoing Pregnancy Mortality Surveillance System to examine all reported pregnancy-related deaths (deaths during or within 1 year of pregnancy that were caused by pregnancy, its complications, or treatment) in states that reported Hispanic origin for 1979-1992. The pregnancy-related mortality ratio was defined as the number of pregnancy-related deaths per 100,000 live births. RESULTS: For the 14-year period, the overall pregnancy-related mortality ratio was 10.3 deaths per 100,000 live births for Hispanic women, 6.0 for non-Hispanic white women, and 25.1 for black women. In Hispanic subgroups, the pregnancy-related mortality ratio was 9.7 for Mexican women and ranged from 7.8 for Cuban women to 13.4 for Puerto Rican women. Pregnancy-induced hypertension was the leading cause of pregnancy-related death for Hispanic women overall. CONCLUSION: Pregnancy-related mortality ratios for Hispanic women were higher than those for non-Hispanic white women, but markedly lower than those for black women. The similarity in socioeconomic status between Hispanic and black women was not an indicator of similar health outcomes. Prevention of pregnancy-related deaths in Hispanic women should include investigation of medical and nonmedical factors and consider the heterogeneity of the Hispanic population.

Adult↗
PubMed1999

Effects of sleep and sleep deprivation on catecholamine and interleukin-2 levels in humans: clinical implications.

The objective of this study was to evaluate the effects of nocturnal sleep, partial night sleep deprivation, and sleep stages on catecholamine and interleukin-2 (IL-2) levels in humans. Circulating levels of catecholamines and IL-2 were sampled every 30 min during 2 nights: undisturbed, baseline sleep and partial sleep deprivation-late night (PSD-L; awake from 0300-0600 h) in 17 healthy male volunteers. Sleep was monitored somnopolygraphically. Sleep onset was associated with a significant (P < 0.05) decline of circulating concentrations of norepinephrine and epinephrine, with a nocturnal nadir that occurred 1 h after nocturnal sleep. On the PSD-L night, levels of norepinephrine and epinephrine significantly (P < 0.05) increased in association with nocturnal awakening. During stage 3-4 sleep, levels of norepinephrine, but not epinephrine, were significantly lower (P < 0.05) compared to average levels during the awake period, stages 1-2 sleep, and rapid eye movement sleep. Nocturnal levels of circulating IL-2 did not change with sleep onset or in relation to PSD-L or the various sleep stages. We conclude that sleep onset is associated with changes in levels of circulating catecholamines. Loss of sleep and disordered sleep with decreases in slow wave sleep may serve to elevate nocturnal catecholamine levels and contribute to cardiovascular disease.

Adult↗
PubMed1999

Psychological responses in family members after the Hebron massacre.

The authors attempted to determine the frequency of severe psychological responses in surviving family members in a religious Muslim culture. Twenty-three wives, twelve daughters and twenty-six sons of heads of households massacred while praying in the Hebron mosque on 25 February 1994 were interviewed with the clinician-administered PTSD scale; 50% of daughters, 39% of wives, and 23% of sons met criteria for PTSD. PTSD or traumatic bereavement occurs with high frequency after a major tragedy in a Moslem society, despite religious admiration of dead martyrs.

Adaptation, Psychological↗
PubMed1998

Increased REM sleep density at admission predicts relapse by three months in primary alcoholics with a lifetime diagnosis of secondary depression.

BACKGROUND: Having previously reported that 3-month relapse was associated with increased admission REM pressure in nondepressed primary alcoholics, we hypothesized that baseline polysomnography would predict outcome in primary alcoholics with a lifetime diagnosis of secondary depression. METHODS: Twenty-one primary alcoholics with secondary depression received polysomnography and the Hamilton Depression Rating Scale during the first and fourth weeks of a 1-month inpatient alcohol treatment program. Exclusion criteria included serious illness, current major alcohol withdrawal symptoms, other Axis I diagnoses, sleep apnea, nocturnal myoclonus, and psychoactive substances within 14 days of polysomnography. Relapse was defined as drinking any alcohol between hospital discharge and 3-month follow-up. RESULTS: Relapsers' total sleep time was reduced, and REM density (reflecting REM sleep ocular activity) was increased significantly throughout admission compared with abstainers. Sleep continuity and Hamilton scores improved by discharge in sober and relapsing alcoholics. Factors derived from admission REM latency, REM percent, and REM density predicted sobriety vs. relapse within 3 months after hospital discharge in 76% of patients. Admission REM density was greater, and total sleep time was less in relapsers than in patients sober at 3 months. CONCLUSIONS: Results suggest that increased REM density and decreased total sleep time at about 2-4 weeks of abstinence predict relapse by 3 months in depressed alcoholics.

Adult↗
PubMed1998

Cellular immunity to varicella-zoster virus in patients with major depression.

The incidence of herpes zoster increases markedly with advancing age, and this appears to be causally related to an age-dependent decline in varicella-zoster virus (VZV)-specific cellular immunity. Psychologic stress has also been linked to the occurrence of herpes zoster, but the mechanism involved has not been investigated. This study examined the relationship between major depression and VZV-specific cellular immunity by comparing VZV-specific responder cell frequency (RCF) in adults with major depression (n = 11) to that in age- and sex-matched nondepressed controls (n = 11) and in a larger group of nondepressed adults who were > or = 60 years old. VZV-specific RCF in depressed patients was markedly reduced compared with the RCF in matched controls (t = 2.7, P < .02). In fact, the levels of VZV-specific RCF in the depressed patients were comparable in magnitude to the low levels found in adults > or = 60 years of age. These data indicate that major depression is associated with a marked decline in VZV-specific cellular immunity.

Adult↗
PubMed1997

Anti-vector immunoglobulin induced by retroviral vectors.

Replication-incompetent retroviruses have been employed as gene therapy vectors in experimental settings for more than a decade. More recently, these vectors have been tested in the clinic as immunotherapeutic agents and anticancer agents. One potential problem with the use of such vectors is the possible development of immune responses directed against the vector particles themselves. Here, we examine immunoglobulin (Ig) responses specific for retroviral vectors derived from murine leukemia virus (MLV). Anti-MLV Ig is seen following intramuscular (i.m.) administration of retroviral vectors in mice, and in nonhuman primates; as expected, these responses are dependent upon the vector dose delivered. Furthermore, serum from vector-treated animals is capable of partially neutralizing vector-mediated transduction of target cells in an in vitro assay. Nevertheless, even in the presence of significant levels of anti-vector Ig in vivo, i.m. administration of retroviral vector is still capable of driving both Ig and cytotoxic T lymphocyte (CTL) responses specific for vector-encoded gene products. This work suggests that although retroviral vectors may readily induce immune responses directed against the vector particles themselves, such responses will not significantly affect the efficiency of these vectors in an immunotherapeutic protocol.

Animals↗
PubMed1997

Alzheimer caregiver stress: basal natural killer cell activity, pituitary-adrenal cortical function, and sympathetic tone.

The association between Alzheimer caregiving and natural killer (NK) cell activity and basal plasma levels of adrenocorticotropic hormone (ACTH), cortisol, beta-endorphin, prolactin, epinephrine, norepinephrine, and neuropeptide Y was determined in 100 spousal Alzheimer caregivers and 33 age- and gender-comparable control volunteers upon intake into a study of the psychological and physiologic impact of caregiving. The relationship between these physiologic measures and individual characteristics such as age, gender, medical status, severity of stress, severity of depressive symptoms, and caregiver burden was tested. In addition, the association between NK activity and alterations of the neuroendocrine measures was investigated. As compared to controls, the Alzheimer caregivers had similar levels of NK activity and of basal plasma neuroendocrine hormones and sympathetic measures. While older age and male gender status were associated with increased levels of ACTH, neither medical caseness, severity of life stress, nor severity of depressive symptoms was associated with alterations in any of the multiple physiologic domains. Classification of Alzheimer caregiver burden identified caregivers who were mismatched in terms of the amount of care they were required to provide and the amount of respite time received. The mismatched caregivers had significantly higher basal plasma ACTH but no change in other physiological measures, as compared to non-mismatched caregivers. NK activity was negatively correlated with plasma levels of neuropeptide Y but not with any of the other neuroendocrine measures. Based on this cross-sectional evaluation of NK activity and neuroendocrine and sympathetic measures, we conclude that most Alzheimer caregivers do not show evidence of altered basal physiology.

Adaptation, Psychological↗
PubMed1997

Foster care: an update.

OBJECTIVE: To inform child and adolescent psychiatrists about the almost 500,000 children now residing in the American foster care system. This overview surveys the pediatric, developmental, and psychiatric needs of these children. METHOD: Child and adolescent psychiatrists, pediatricians, a child welfare researcher, a social worker, and a psychologist developed a consensus paper from their experience with child welfare and a review of the literature in their respective fields. RESULTS: Being in foster care is a defining experience in these children's lives. They are at risk in myriad ways: for instance, being poor, having chronic health deficits, experiencing the trauma of abuse and neglect, and suffering from a gamut of emotional challenges. Evolutionary developments in foster care such as therapeutic foster homes, kinship care, and changes in Medicaid funding will continue to alter the system. CONCLUSIONS: Foster children are a huge reservoir of unmet pediatric and psychiatric needs; research on them is spotty at best. It is hoped that child and adolescent psychiatrists will meet the challenges these youngsters present and will advocate for them.

Adolescent↗
PubMed1997

Effectiveness of occlusion therapy in ametropic amblyopia: a pilot study.

AIMS/BACKGROUND: To examine the relative contributions of non-specific (for example, spectacle correction) and specific (that is, occlusion therapy) treatment effects on children with ametropic amblyopia. To assess the importance and practicality of objectively confirming the prescribed occlusion dose. METHODS: Subjects were entered into a two phase trial. In the first ('pretreatment') subjects were provided with spectacle correction and underwent repeat visual acuity (VA) and contrast sensitivity (CS) testing until acuity in their amblyopic eye had stabilised. Subjects then progressed to the second phase ('treatment') in which they underwent direct, unilateral occlusion for 1 hour per day for 4 weeks. Patching was objectively monitored using an occlusion dose monitor. RESULTS: Eight subjects completed the trial, all but one of whom achieved > 80% concordance with the occlusion regimen. Within the pretreatment phase, mean amblyopic eye VA improved by 0.19 log units (p = 0.008) while mean CS gained 0.09 log units (p = 0.01). An identical improvement in mean VA was recorded in the fellow eyes (p = 0.03) while mean CS gained 0.11 log units (p = 0.02). Within the treatment phase, mean VA further improved (0.12 log units, p = 0.009) although this gain had halved by the end of treatment and was no longer statistically significant (p = 0.09). CONCLUSIONS: Visual performance improved significantly during pretreatment whereas further gains seen during occlusion were not sustained. Evaluation of occlusion regimens must take into consideration the potentially confounding influence of 'pretreatment effects' and the necessity to confirm objectively the occlusion dose a child receives.

Amblyopia↗
PubMed1996

Psychiatric and developmental disorders in families of children with attention-deficit hyperactivity disorder.

OBJECTIVE: To evaluate whether a pediatric family history obtained via a brief parent interview would reveal a high prevalence of psychiatric and developmental disorders in the family members of children with attention-deficit hyperactivity disorder (ADHD) compared with a group of children with another chronic developmental disability, Down syndrome (DS). DESIGN: A controlled cross-sectional group comparison study. SETTING: An interdisciplinary hyperactivity and learning problem clinic and a DS clinic located in a large, urban tertiary care teaching hospital in Chicago, Ill. PARTICIPANTS: A total of 140 children with ADHD and 163 children with DS of comparable socioeconomic status. MEASURES: Using a screening questionnaire and parent interview, the development pediatricians obtained a family history. RESULTS: By parent report, children with ADHD were significantly more likely than the control children with DS to have a parent affected by alcoholism (P = .007), other drug abuse (P < .001), depression (P < .001), delinquency (P < .001), learning disabilities (P < .001), and ADHD (P < .001). Similar patterns were evidenced in other first- and second-degree relatives. CONCLUSIONS: The high reported frequency of psychiatric and developmental disorders in the families of children with ADHD requires that the treating clinician explore the area of family psychiatric and developmental history and use the findings to formulate a comprehensive treatment plan that includes anticipatory guidance and psychosocial intervention.

Adolescent↗