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Biomedical subjects

A H Miller

Publications and source records attributed to A H Miller.

At least 19 recordsLinked to original sources
PubMed2002

Association between decreased serum tryptophan concentrations and depressive symptoms in cancer patients undergoing cytokine therapy.

Cytokine therapy for cancer or viral diseases is accompanied by the development of depressive symptoms in a significant proportion of patients. Despite the increasing number of studies on the neurotoxic effects of cytokines, the mechanisms by which cytokines induce depressive symptoms remain largely unknown. In view of the relationship between neurotransmitter precursors and mood, the present study aimed at assessing the relationship between serum concentrations of the amino acids tryptophan and tyrosine, major precursors of serotonin and norepinephrine respectively, and depressive symptoms in cancer patients undergoing cytokine therapy. Sixteen cancer patients eligible to receive immunotherapy with interleukin-2 and/or interferon-alpha participated in the study. At baseline and after one week and one month of therapy, depressive symptoms were assessed using the Montgomery-Asberg Depression Rating Scale (MADRS), and blood samples were collected for the determination of the large neutral amino acids (LNAA) (tryptophan, tyrosine, valine, leucine, isoleucine, phenylalanine) which compete for transport across the blood-brain barrier. Serum concentrations of tryptophan as well as the tryptophan/LNAA ratio significantly decreased between baseline, one week and one month of therapy. The development and severity of depressive symptoms, especially anorexia, pessimistic thoughts, suicidal ideation and loss of concentration were positively correlated with the magnitude of the decreases in tryptophan concentrations during treatment. These findings indicate that the development of depressive symptoms in patients undergoing cytokine therapy could be mediated by a reduced availability of the serotonin relevant amino acid precursor, tryptophan.

Adult↗
PubMed2001

Paroxetine for the prevention of depression induced by high-dose interferon alfa.

BACKGROUND: Depression commonly complicates treatment with the cytokine interferon alfa-2b. Laboratory animals pretreated with antidepressants have less severe depression-like symptoms after the administration of a cytokine. We sought to determine whether a similar strategy would be effective in humans. METHODS: In a double-blind study of 40 patients with malignant melanoma who were eligible for high-dose interferon alfa therapy, we randomly assigned 20 patients to receive the antidepressant paroxetine and 20 to receive placebo. The treatment was begun 2 weeks before the initiation of interferon alfa and continued for the first 12 weeks of interferon alfa therapy. RESULTS: During the first 12 weeks of interferon alfa therapy, symptoms consistent with a diagnosis of major depression developed in 2 of 18 patients in the paroxetine group (11 percent) and 9 of 20 patients in the placebo group (45 percent) (relative risk, 0.24; 95 percent confidence interval, 0.08 to 0.93). Severe depression necessitated the discontinuation of interferon alfa before 12 weeks in 1 of the 20 patients in the paroxetine group (5 percent), as compared with 7 patients in the placebo group (35 percent) (relative risk, 0.14; 95 percent confidence interval, 0.05 to 0.85). The incidence of adverse events was similar in the two groups. CONCLUSIONS: In patients with malignant melanoma, pretreatment with paroxetine appears to be an effective strategy for minimizing depression induced by interferon alfa.

Adult↗
PubMed2001

Glucocorticoid receptors in major depression: relevance to pathophysiology and treatment.

Hyperactivity of the hypothalamic--pituitary--adrenal (HPA) axis has been reliably observed in patients with major depression. One of the primary features of this HPA axis hyperactivity is reduced sensitivity to the inhibitory effects of the glucocorticoid dexamethasone on the production of adrenocorticotropic hormone and cortisol during the dexamethasone suppression test and, more recently, the dexamethasone--corticotropin-releasing hormone test. Because the effects of glucocorticoids are mediated by intracellular receptors including, most notably, the glucocorticoid receptor (GR), a number of studies have considered the possibility that the number and/or function of GRs are reduced in depressed patients. Moreover, whether antidepressants act by reversing these putative GR changes has been examined. The extant literature on GR receptors in major depression was reviewed along with studies examining the impact of antidepressants on the GR. The data support the hypothesis that the function of the GR is reduced in major depression in the absence of clear evidence of decreased GR expression. The data also indicate that some antidepressants have direct effects on the GR, leading to enhanced GR function and increased GR expression. Hypotheses regarding the mechanism of these receptor changes involve relevant second messenger pathways that regulate GR function. The findings indicate that the GR is an important molecular target in major depression. Further elucidation of the biochemical and molecular mechanisms involved in GR changes in major depression is an exciting frontier that will no doubt lead to new insights into the pathophysiology and treatment of affective disorders.

Anti-Inflammatory Agents↗
PubMed2001

Antidepressants enhance glucocorticoid receptor function in vitro by modulating the membrane steroid transporters.

1. Previous data demonstrate that the tricyclic antidepressant, desipramine, induces glucocorticoid receptor (GR) translocation from the cytoplasm to the nucleus in L929 cells and increases dexamethasone-induced GR-mediated gene transcription in L929 cells stably transfected with the mouse mammary tumour virus-chloramphenicol acetyltransferase (MMTV-CAT) reporter gene (LMCAT cells) (Pariante et al., 1997). 2. To extend these findings, the present study has investigated the effects of 24 h coincubation of LMCAT cells with dexamethasone and amitriptyline, clomipramine, paroxetine, citalopram or fluoxetine. 3. All antidepressants, except fluoxetine, enhanced GR-mediated gene transcription, with clomipramine having the greatest effect (10 fold increase). Twenty-four hours coincubation of cells with desipramine, clomipramine or paroxetine, also enhanced GR function in the presence of cortisol, but not of corticosterone. 4. It is proposed that these effects are due to the antidepressants inhibiting the L929 membrane steroid transporter, which actively extrudes dexamethasone and cortisol from the cell, but not corticosterone. This is further confirmed by the fact that clomipramine failed to enhance GR-mediated gene transcription in the presence of dexamethasone when the membrane steroid transporter was blocked by verapamil. 5. The membrane steroid transporters that regulate access of glucocorticoids to the brain in vivo, like the multiple drug resistance p-glycoprotein, could be a fundamental target for antidepressant action.

Animals↗
PubMed2001

The neuroimmunology of stress and depression.

This article reviews evidence that shows a bidirectional relationship between the brain and the immune system. As a result of this relationship, mental factors such as stress and depression have been shown to affect immune system functioning, with both immunosuppression and immune activation being reported. Stress and depression also have been associated with worse outcomes in immune-related disorders including cancer and infectious diseases suggesting that stress/depression effects on the immune system are clinically relevant to disease expression. Conversely, several lines of evidence suggest that immune system activation such as during infectious diseases, cancer, and autoimmune disorders is associated with the development of behavioral symptoms similar to those seen in the context of chronic stress or major depression. These findings implicate a role for the immune system in the cause of behavioral disorders in a wide range of medical illnesses. Finally, a paradigm is proposed in which abnormal functioning of either the hypothalamic-pituitary-adrenal (HPA) axis or the inflammatory response system disrupts feedback regulation of both neuroendocrine and immune systems contributing to the development of neuropsychiatric and immunologic disorders.

Brain↗
PubMed2001

Altered pituitary-adrenal axis responses to provocative challenge tests in adult survivors of childhood abuse.

OBJECTIVE: Early adverse life events may predispose individuals to the development of mood and anxiety disorders in adulthood, perhaps by inducing persistent changes in corticotropin-releasing factor (CRF) neuronal systems. The present study sought to evaluate pituitary-adrenal responses to standard hypothalamic-pituitary-adrenal axis challenge tests in adult female survivors of childhood abuse with and without major depressive disorder. METHOD: Plasma ACTH and cortisol responses to the administration of 1 microg/kg ovine CRF and plasma cortisol responses to the administration of 250 microg ACTH(1-24) were measured in healthy women without early life stress (N=20), women with childhood abuse without major depressive disorder (N=20), women with childhood abuse and major depressive disorder (N=15), and women with major depression but no early life stress (N=11). RESULTS: Abused women without major depressive disorder exhibited greater than usual ACTH responses to CRF administration, whereas abused women with major depressive disorder and depressed women without early life stress demonstrated blunted ACTH responses. In the ACTH(1-24) stimulation test, abused women without major depressive disorder exhibited lower baseline and stimulated plasma cortisol concentrations. Abused women with comorbid depression more often suffered from posttraumatic stress disorder and reported more recent life stress than abused women without major depressive disorder. CONCLUSIONS: These findings suggest sensitization of the anterior pituitary and counterregulative adaptation of the adrenal cortex in abused women without major depressive disorder. On subsequent stress exposure, women with a history of childhood abuse may hypersecrete CRF, resulting in down-regulation of adenohypophyseal CRF receptors and symptoms of depression and anxiety.

Adrenocorticotropic Hormone↗
PubMed2001

Higher than normal plasma interleukin-6 concentrations in cancer patients with depression: preliminary findings.

OBJECTIVE: This study investigated whether cancer patients with and without major depression exhibit immune system abnormalities similar to those reported in medically healthy, depressed subjects without cancer. METHOD: The study subjects consisted of patients diagnosed with pancreatic, esophageal, or breast cancer. Other groups consisted of subjects with major depression (without cancer) and healthy comparison subjects. Subjects' diagnoses were made with the Structured Clinical Interview for DSM-III-R. Severity of depression was measured with the Hamilton Depression Rating Scale. Plasma concentrations of interleukin-6 (IL-6) and postdexamethasone cortisol were measured. RESULTS: Cancer patients with depression had markedly higher plasma concentrations of IL-6 than healthy comparison subjects and cancer patients without depression. Although significant correlations were found between Hamilton depression scale scores and plasma concentrations of postdexamethasone cortisol, no significant correlations were found between plasma IL-6 and postdexamethasone cortisol concentrations. CONCLUSIONS: Higher than normal plasma IL-6 concentrations were associated with a diagnosis of major depression in cancer patients. IL-6 may contribute to sickness behavior that has overlapping symptoms with major depression.

Adult↗
PubMed2001

The steroid receptor antagonists RU40555 and RU486 activate glucocorticoid receptor translocation and are not excreted by the steroid hormones transporter in L929 cells.

RU40555 is a recently available glucocorticoid receptor (GR) antagonist that differs from RU486 by a methyl radical. We have used the mouse fibroblast cell line L929 to study the in vitro effects of RU40555 on GR translocation and function and on the membrane steroid hormones transporter. The results showed that: 1) RU40555 competed for the binding of labelled dexamethasone (Dex) with a K(i) of 2.4 nM; 2) both RU40555 and RU486 were equally potent inhibitors of Dex-induced GR-mediated gene transcription; 3) maximum GR translocation induced by micromolar concentrations of Dex and the GR antagonists was approximately 30-55% loss in the cytoplasmic GR and approximately 40-90% increase in the nuclear GR (assessed by GR immunostaining in cytoplasm and nucleus and western blots of immunoprecipitated GR protein in cytosolic and nuclear fractions) and was similar for the two antagonists; 4) at nanomolar concentrations, RU40555 and RU486 induced more GR translocation than Dex (assessed by [(3)H]Dex binding and western blot of immunoreactive GR in the same cytosolic homogenates); 5) blocking the steroids membrane transporter with verapamil (100 microM) in the presence of Dex (10 nM) increased GR translocation to levels similar to those induced by RU40555 (10 nM) and RU486 (10 nM) alone; 6) verapamil did not affect GR translocation in the presence of RU40555 or RU486. These data demonstrate similar quantitative effects on GR translocation by RU486 and the new GR antagonist, RU40555. Moreover, RU40555, like RU486, is an effective GR antagonist. Finally, there is no evidence that the intracellular concentrations of RU40555 or RU486 are regulated by the steroids membrane transporter in L929 cells.

Analysis of Variance↗
PubMed2001

Priapism associated with conventional and atypical antipsychotic medications: a review.

BACKGROUND: Priapism is a prolonged, usually painful, and persistent penile erection not usually associated with sexual stimuli, resulting from a disturbance in the normal regulatory mechanisms that initiate and maintain penile flaccidity. This infrequent adverse event of antipsychotic medication use requires emergency evaluation and has potentially serious long-term sequelae including erectile dysfunction. Clinicians prescribing antipsychotic medications should be aware of this rare but serious adverse event. METHOD: A computerized search, using the MEDLINE database (1966-summer 2000), located cases of priapism associated with most conventional antipsychotics as well as with clozapine, risperidone, and olanzapine. The search included no restrictions on languages. Keywords included priapism combined with antipsychotic agents and the names of the currently available atypical antipsychotics. Twenty-nine publications were located using these parameters. Additional publications were reviewed for general background on pathophysiology, evaluation, and management. The quality of the evidence reviewed is limited by the observational and uncontrolled nature of case reports, case series. and review articles. RESULTS: Psychotropic-induced priapism is currently believed to be caused by the alpha1-adrenergic antagonism of these medications. Detumescence is sympathetically mediated, and alpha1-adrenergic antagonism (within the corpora cavernosa) inhibits detumescence. The propensity of individual antipsychotics to induce priapism can presumably be estimated on the basis of alpha1adrenergic blockade affinities. Of the conventional antipsychotics, chlorpromazine and thioridazine have the greatest alpha1-adrenergic affinity and have been most frequently reported to be associated with priapism. Of the atypical antipsychotics, risperidone has greater alpha1-adrenergic affinity, although 3 of the 5 currently U.S. Food and Drug Administration (FDA)-approved atypicals have been reported to be associated with priapism. CONCLUSION: Virtually all antipsychotic medications have been reported to rarely cause priapism due to their alpha-adrenergic antagonism. This adverse event should be considered a urologic emergency. Clinicians should be familiar with this infrequent serious adverse event of antipsychotic medications.

Antipsychotic Agents↗
PubMed2001

Sexual side effects associated with conventional and atypical antipsychotics.

The sexual side effects of psychotropic medications are becoming increasingly recognized in clinical psychiatry. The magnitude of the problem of sexual side effects associated with antipsychotic medications has yet to be fully elucidated, but a multitude of references in the literature demonstrate the importance of these side effects in both men and women. All currently used antipsychotic medications are associated with sexual side effects of various types. Although each antipsychotic medication may have a specific side effect profile determined by its various receptor affinities and by the degree to which it elevates serum prolactin, there is currently no evidence that specific side effects can be predicted. Sexual side effects can be categorized according to the phase of the sexual response cycle with which they interfere. Suggestions for clinical evaluation and treatment options are provided, including risk factor modification, dose reduction, switching agents, and addition of other agents. Sexual side effects associated with conventional and atypical antipsychotic medications represent an underestimated and understudied set of side effects that may diminish a patient's quality of life and lead to treatment noncompliance. Clinicians prescribing antipsychotic medications should be familiar with the classification, evaluation, and treatment of these side effects.

Antipsychotic Agents↗
PubMed2000

Viral infection of developing GABAergic neurons in a model of hippocampal disinhibition.

Mechanisms by which perinatal viral infections can disrupt hippocampal development and cause selective neuronal death may have implications for temporal lobe epilepsy and schizophrenia. Despite abnormalities of inhibitory interneurons in these diseases, the causal relationships between such neurotransmitter changes and viral infections remain unclear. This relationship was examined in a model in which rats, infected with lymphocytic choriomeningitis virus (LCMV) as neonates, manifest a gradual loss of hippocampal dentate granule cells and neuronal hyperexcitability. The current data demonstrate that GABAergic interneurons are dual immunostained for LCMV antigens prior to the loss of dentate granule cells, supporting the hypothesis that LCMV may disrupt developing inhibitory circuits causing unbalanced excitatory neurotransmission and the eventual death of dentate granule cells due to excitotoxicity.

Animals↗
PubMed2000

Pituitary-adrenal and autonomic responses to stress in women after sexual and physical abuse in childhood.

CONTEXT: Evidence suggests that early adverse experiences play a preeminent role in development of mood and anxiety disorders and that corticotropin-releasing factor (CRF) systems may mediate this association. OBJECTIVE: To determine whether early-life stress results in a persistent sensitization of the hypothalamic-pituitary-adrenal axis to mild stress in adulthood, thereby contributing to vulnerability to psychopathological conditions. DESIGN AND SETTING: Prospective controlled study conducted from May 1997 to July 1999 at the General Clinical Research Center of Emory University Hospital, Atlanta, Ga. PARTICIPANTS: Forty-nine healthy women aged 18 to 45 years with regular menses, with no history of mania or psychosis, with no active substance abuse or eating disorder within 6 months, and who were free of hormonal and psychotropic medications were recruited into 4 study groups (n = 12 with no history of childhood abuse or psychiatric disorder [controls]; n = 13 with diagnosis of current major depression who were sexually or physically abused as children; n = 14 without current major depression who were sexually or physically abused as children; and n = 10 with diagnosis of current major depression and no history of childhood abuse). MAIN OUTCOME MEASURES: Adrenocorticotropic hormone (ACTH) and cortisol levels and heart rate responses to a standardized psychosocial laboratory stressor compared among the 4 study groups. RESULTS: Women with a history of childhood abuse exhibited increased pituitary-adrenal and autonomic responses to stress compared with controls. This effect was particularly robust in women with current symptoms of depression and anxiety. Women with a history of childhood abuse and a current major depression diagnosis exhibited a more than 6-fold greater ACTH response to stress than age-matched controls (net peak of 9.0 pmol/L [41.0 pg/mL]; 95% confidence interval [CI], 4.7-13.3 pmol/L [21.6-60. 4 pg/mL]; vs net peak of 1.4 pmol/L [6.19 pg/mL]; 95% CI, 0.2-2.5 pmol/L [1.0-11.4 pg/mL]; difference, 8.6 pmol/L [38.9 pg/mL]; 95% CI, 4.6-12.6 pmol/L [20.8-57.1 pg/mL]; P<.001). CONCLUSIONS: Our findings suggest that hypothalamic-pituitary-adrenal axis and autonomic nervous system hyperreactivity, presumably due to CRF hypersecretion, is a persistent consequence of childhood abuse that may contribute to the diathesis for adulthood psychopathological conditions. Furthermore, these results imply a role for CRF receptor antagonists in the prevention and treatment of psychopathological conditions related to early-life stress. JAMA. 2000;284:592-597

Adrenocorticotropic Hormone↗
PubMed2000

Double jeopardy: schizophrenia and substance use.

OBJECTIVE: Although the clinical reality of substance dependence and/or abuse among schizophrenia patients is widely acknowledged, the interaction of these diagnoses is not well understood. Perhaps the largest study documenting the comorbidity of substance abuse is the Epidemiologic Catchment Area (ECA) study, which found the rate to be 47% in schizophrenia patients (1). The present study examined substance use and compared the broad categories of substance users versus nonusers vis-à-vis schizophrenic symptomatology, hospitalizations, compliance, and demographic variables. We further examined the two subcategories of alcohol versus other substances of abuse (hereafter called "drugs") to determine differences. METHODS: Data were collected by the same person retrospectively from the charts of schizophrenia outpatients in a public inner city mental health center. Patients must have had at least 10 outpatient visits within a 2-year period for data to be used. RESULTS: Data were compiled from 262 charts. Of the schizophrenia patients, 55% had a history of past or current substance use. Consistent with previous reports, substance-using schizophrenia patients were more likely to be younger and male than nonusers. Substance users had significantly more hospitalizations and more outpatient visits with positive symptoms. There was also a higher rate of missed appointments in the substance-using patients, and there was a correlation between missed appointments and hospitalizations. As for the differences in the two subcategories of alcohol versus drugs, drug users had notably more negative symptoms, except in those cases for which the alcohol user required treatment for alcoholism. Current drug use also correlated with higher tardive dyskinesia scores, higher incidence of cognitive deficiency, less education, and higher average neuroleptic dose than with nonuse or alcohol use. CONCLUSION: These results extend the previous findings to a large inner city group of subjects and to a population that is at high risk for relapse. Our findings further emphasize the impact of substance use on outcome in schizophrenia and the need for more research on the nature and treatment of the patient with a dual diagnosis.

Adult↗
PubMed1999

Lymphocytic responses and the gradual hippocampal neuron loss following infection with lymphocytic choriomeningitis virus (LCMV).

Infection of rats with LCMV is known to cause a bi-phasic neurodegeneration characterized by acute T lymphocyte-mediated cerebellar damage, followed by gradual hippocampal neuron loss that occurs by an undefined mechanism. We found infiltration of CD8 + T-cells (but not CD4 + or NK cells) in the hippocampus which correlated with the acute phase, but not the chronic hippocampal degenerative phase. While immunosuppression of T lymphocytes protected the cerebellum and revealed the infection of corticohippocampal glia, the degeneration in the hippocampus was unabated. These data suggest that T lymphocytes control glial infection and mediate degeneration in the cerebellum but not the hippocampus.

Animals↗
PubMed1999

Endogenous glucocorticoids protect against cytokine-mediated lethality during viral infection.

Certain cytokines activate the hypothalamic-pituitary-adrenal axis for glucocorticoid release, and these hormones can protect against cytokine-mediated pathologies. However, endogenous activation of such a pathway has not been established during infections. A prominent glucocorticoid response peaks 36 h following murine CMV (MCMV) infection, coincident with circulating levels of the cytokines IL-12, IFN-gamma, TNF, and IL-6, and dependent on IL-6 for maximal release. These studies examined functions of the hormone induction. Mice rendered glucocorticoid deficient by adrenalectomy were more susceptible than intact mice to MCMV-induced lethality, and the increased sensitivity was reversed by hormone replacement. Lack of endogenous glucocorticoids resulted in increases in IL-12, IFN-gamma, TNF, and IL-6 production, as well as in mRNA expression for a wider range of cytokines, also including IL-1 alpha and IL-1 beta. Viral burdens did not increase, and actually decreased, in the livers of glucocorticoid-deficient mice. TNF, but not IFN-gamma, was required for increased lethality in the absence of endogenous hormone. These results conclusively demonstrate the importance of induced endogenous glucocorticoids in protection against life-threatening effects resulting from infection-elicited cytokine responses. Taken together with the dependence on induced IL-6, they document existence of an immune system-hypothalamic-pituitary-adrenal axis pathway for regulating endogenous responses to viral infections.

Administration, Oral↗
PubMed1999

Effects of cytokines on glucocorticoid receptor expression and function. Glucocorticoid resistance and relevance to depression.

Our data indicate that the proinflammatory cytokine, IL-1alpha inhibits GR translocation and hormone-induced GR-mediated gene transcription, and, in conjunction with previous in vivo and in vitro studies, can be interpreted to suggest that cytokines have the capacity to contribute to glucocorticoid resistance and thus the pathophysiology of depression. In addition, data from our mouse viral studies in glucocorticoid deficient animals demonstrate that endogenous glucocorticoids modulate a delicate balance between viral defense and cytokine toxicity. Finally, the antidepressant, DMI, has been found to enhance GR translocation and GR-mediated gene transcription and thus may provide a useful strategy for adjusting neuroendocrine setpoints in vivo. Taken together, these findings suggest that factors which modulate glucocorticoid action (e.g. cytokines and antidepressants) will be relevant contributors to disease expression including behavioral toxicity and sickness behavior.

Animals↗
PubMed1999

The effects of neonatal stress on brain development: implications for psychopathology.

Recent studies have focused on the behavioral and neurobiological sequella of exposure to early adverse events. We hypothesize that early adverse experiences result in an increased sensitivity to the effects of stress later in life and render an individual vulnerable to stress-related psychiatric disorders. This vulnerability may be mediated by persistent changes in corticotropin-releasing-factor (CRF)-containing neurons, the hypothalamic-pituitary-adrenal axis, and the sympathetic nervous system. We therefore present an overview of the CRF system and its role as a mediator in the development of the stress response, major depression, and posttraumatic stress disorder. The literature pertaining to behavioral and neurobiological alterations associated with exposure to early adverse life events in rodents, nonhuman primates, and humans is reviewed. We focus on animal models that precipitate depressive and anxiety symptoms while producing neuroendocrine alterations that mimic those seen in adults with those disorders. The literature integrating neurobiological and behavioral consequences of early life stress is also reviewed, focusing primarily on infants born to mothers with depression and on infants who were abused or neglected.

Adult↗