Biomedical subjects

S A West

Publications and source records attributed to S A West.

At least 19 recordsLinked to original sources

PubMed2000

Sex allocation and population structure in apicomplexan (protozoa) parasites.

Establishing the selfing, rate of parasites is important for studies in clinical and epidemiological medicine as well as evolutionary biology Sex allocation theory offers a relatively cheap and easy way to estimate selfing rates in natural parasite populations. Local mate competition (LMC) theory predicts that the optimal sex ratio (r*; defined as proportion males) is related to the selfing rate (s) by the equation r* = (1-s)/2. In this paper, we generalize the application of sex allocation theory across parasitic protozoa in the phylum Apicomplexa. This cosmopolitan phylum consists entirely of parasites, and includes a number of species of medical and veterinary importance. We suggest that LMC theory should apply to eimeriorin intestinal parasites. As predicted, data from 13 eimeriorin species showed a female-biased sex ratio, with the sex ratios suggesting high levels of selfing (0.8-1.0). Importantly, our estimate of the selfing rate in one of these species, Toxoplasma gondii, is in agreement with previous genetic analyses. In contrast, we predict that LMC theory will not apply to the groups in which syzygy occurs (adeleorins, gregarines and piroplasms). Syzygy occurs when a single male gametocyte and a single female gametocyte pair together physically or in close proximity, just prior to fertilization. As predicted, data from four adeleorin species showed sex ratios not significantly different from 0.5.

Animals↗

PubMed1999

The effect of lumbar puncture stress on dopamine and serotonin metabolites in human cerebrospinal fluid.

In order to examine concentrations of cerebrospinal fluid (CSF) neurochemicals, the technique of lumbar puncture is typically used. However, the effect of the intrinsic stress of undergoing a lumbar puncture on CSF monoamine concentrations in humans has not yet been established. We used lumbar puncture followed 3 h later by continuous CSF sampling to examine the effect of lumbar puncture on levels of the dopamine and serotonin metabolites homovanillic acid (HVA) and 5-hydroxyindoleacetic acid (5-HIAA), respectively. Additionally, we examined the effect of lumbar puncture on the CSF HVA to 5-HIAA ratio. Immediately post lumbar puncture, CSF concentrations of HVA and 5-HIAA were, respectively, only 51 and 54% of the mean levels detected hours later. However, the HVA to 5-HIAA ratio remained stable during lumbar puncture. While HVA and 5-HIAA levels in CSF obtained via lumbar puncture reflect highly variable responses to the stress of the procedure, the ratio of these metabolites is unaffected.

Adult↗

PubMed1999

Familial rates of affective and substance use disorders in patients with first-episode mania.

BACKGROUND: One explanation for the high co-occurrence between bipolar and substance use disorders is that substance abuse may precipitate affective symptoms in patients who otherwise may have not had the genetic risk for developing an affective illness. Previous studies comparing familial rates of affective illness between bipolar patients with and without alcohol use have provided conflicting results. We hypothesized that patients with bipolar disorder and antecedent alcohol abuse would have lower familial rates of affective illness than bipolar patients without antecedent alcohol abuse. METHODS: Family history data were obtained on 275 first-degree relatives of 51 patients hospitalized for a first manic episode using the Family History Research Diagnostic Criteria. RESULTS: Patients with bipolar disorder and antecedent alcohol abuse had lower familial rates of affective illness than patients with bipolar disorder without antecedent alcohol abuse (two-tailed Fisher's exact, P = 0.003). There was no statistically significant difference in the familial rates of affective illness between bipolar patients with and without antecedent drug abuse (other than alcohol). Patients with bipolar disorder and antecedent alcohol abuse had a significantly older age of onset of affective illness (27.6 years) than patients with bipolar disorder without antecedent alcohol abuse (20.6 years, z = 3.3, df = 1, P = 0.0009). There was no statistical difference in age of onset of affective illness between the patients with antecedent drug abuse and the patients without antecedent drug abuse. LIMITATIONS: Future studies with a larger number of bipolar patients, direct structured interviews of family members and better differentiation between substance abuse and dependence syndromes are needed to extend and replicate this pilot study. CONCLUSIONS: Our study suggests that there may be a subset of bipolar patients who have antecedent alcohol abuse and a subset who develop alcohol abuse after the onset of bipolar disorder. We further speculate that alcohol abuse may precipitate mania in some patients with bipolar disorder.

Adolescent↗

PubMed1999

Low CSF concentration of a dopamine metabolite in tobacco smokers.

OBJECTIVE: To screen for dopaminergic abnormalities in tobacco smokers and patients with posttraumatic stress disorder (PTSD), the authors determined serial CSF and plasma concentrations of the dopamine metabolite homovanillic acid (HVA). METHOD: Continuous subarachnoid sampling was used to obtain 37 serial CSF samples over 6 hours in 13 normal volunteers and 11 patients with combat-related PTSD; 10 smoked and 14 had never smoked. The smokers were abstinent from tobacco for 1 1 to 17 hours. RESULTS: The smokers had markedly lower CSF, but not plasma, HVA levels. Their CSF HVA concentrations averaged only 54% of the concentrations of the nonsmokers, independent of diagnosis. CONCLUSIONS: Smokers' low CSF concentrations of HVA may be associated either with chronic inhalation of nicotine or other constituents of tobacco smoke or with acute abstinence. Any possible basal dopaminergic abnormalities in patients with PTSD are small relative to the abnormalities associated with smoking.

Adult↗

PubMed1999

Serial CSF corticotropin-releasing hormone levels and adrenocortical activity in combat veterans with posttraumatic stress disorder.

OBJECTIVE: The authors sought to carefully test, by using a technique of continuous CSF sampling, the hypothesis that basal elevations in CSF corticotropin-releasing hormone (CRH) concentrations exist in patients with posttraumatic stress disorder (PTSD). They also sought to assess the relationship among PTSD symptoms, adrenocortical activity, and CSF CRH levels. METHOD: CSF was withdrawn by means of a flexible, indwelling subarachnoid catheter over a 6-hour period, and hourly CSF concentrations of CRH were determined for 11 well-characterized combat veterans with PTSD and 12 matched normal volunteers. Twenty-four-hour urinary-free cortisol excretion was also determined. PTSD and depressive symptoms were correlated with the neuroendocrine data. RESULTS: Mean CSF CRH levels were significantly greater in PTSD patients than in normal subjects (55.2 [SD = 16.4] versus 42.3 pg/ml [SD = 15.6]). No correlation was found between CSF CRH concentrations and PTSD symptoms. While there was no significant difference between groups in 24-hour urinary-free cortisol excretion, the correlation between 24-hour urinary-free cortisol excretion and PTSD symptoms was negative and significant. CONCLUSIONS: By using a serial CSF sampling technique, the authors found high basal CSF CRH concentrations and normal 24-hour urinary-free cortisol excretion in combat veterans with PTSD, a combination that appears to be unique among psychiatric conditions studied to date.

Adrenal Cortex↗

PubMed1998

Symptom correlates of attentional improvement following hospitalization for a first episode of affective psychosis.

BACKGROUND: This study examined patients with a first-episode of affective psychosis during acute and compensated states in order to determine whether changes in attentional functioning over time were accompanied by changes in the severity of psychotic or affective symptoms. METHODS: Attentional performance was measured in patients (n = 27) using the degraded-stimulus continuous Performance Test (CPT) and symptoms were assessed at the time of index hospitalization, and 2 months after discharge. A comparison group of normal volunteers (n = 31) also performed the CPT two months apart. RESULTS: Patients performed significantly worse than controls at the initial testing but not at follow-up. The improvement in attentional performance significantly correlated with decreased severity of manic symptoms. CONCLUSIONS: Results suggest attentional dysfunction is a state-dependent characteristic of mania, and may provide an additional measure of clinical improvement following treatment.

Adult↗

PubMed1998

Continuous covariability of dopamine and serotonin metabolites in human cerebrospinal fluid.

BACKGROUND: Experiments in lower animals and humans have demonstrated the existence of functional interactions between serotonin and dopamine in neuronal tissue. However, the relationship between parameters of serotonin and dopamine neuronal activity over time within the central nervous system (CNS) of the individual human has not yet been established. METHODS: We used continuous cerebrospinal fluid (CSF) sampling over 6 hours to test the hypothesis that the serotonin metabolite 5-hydroxyindoleacetic acid (5-HIAA) and the dopamine metabolite homovanillic acid (HVA) significantly covary in concentration over time. Two groups of normal volunteers (total n = 16) were studied at separate hospitals and CSF was assayed for 5-HIAA and HVA by high-performance liquid chromatography (HPLC). Three subjects underwent repeat CSF-withdrawal procedures after a 6-week interval. RESULTS: Strong and sustained positive covariability in concentrations of HVA and 5-HIAA was observed in the CSF of individual humans. High intraindividual correlation coefficients were +0.897 and +0.871 in the two normal volunteer groups. The HVA to 5-HIAA concentration ratio in CSF was 2.2 +/- 0.7 with very little variability over intervals ranging from minutes to weeks. CONCLUSIONS: The balance between CSF dopamine and serotonin metabolite concentrations remains relatively constant over time in healthy humans. Serial measures of CSF dopamine and serotonin metabolites within the same person could be an effective model in which to explore the interrelationships between these systems in various psychiatric syndromes, in response to drug treatment, and during provactive testing.

Adult↗

PubMed1998

Twelve-month outcome after a first hospitalization for affective psychosis.

BACKGROUND: We studied the 12-month course of illness after a first hospitalization for affective psychosis to identify potential outcome predictors in this rarely studied patient population. METHODS: For this study, 109 patients consecutively admitted for their first psychiatric hospitalization for treatment of affective psychosis were recruited. Diagnostic, symptomatic, and functional evaluations were obtained at the index hospitalization and at 2, 6, and 12 months after discharge to assess syndromic, symptomatic, and functional outcome predictors. Factors associated with outcome were identified by means of multivariate analyses. RESULTS: Fifty-six percent of the patients achieved syndromic recovery during the 12-month follow-up. Full treatment compliance was associated with more frequent and rapid syndromic recovery. Full compliance was more common in white patients and in patients without substance abuse. Only 35% of these patients achieved symptomatic recovery during this same 12-month interval, and, similarly, only 35% achieved functional recovery. Symptomatic recovery was delayed in patients with substance abuse and was associated with higher socioeconomic status. Higher socioeconomic status was also associated with functional recovery, as was good premorbid function. CONCLUSIONS: Few patients achieved a favorable outcome in the year after a first hospitalization for an affective psychosis. Low socioeconomic status, poor premorbid function, treatment noncompliance, and substance abuse were associated with lower rates or delayed onset of recovery.

Adult↗

PubMed1998

Wolbachia in two insect host-parasitoid communities.

Wolbachia form a group of intracellular bacteria that alter reproduction in their arthropod hosts. Two major phylogenetic subdivisions (A and B) of Wolbachia occur. Using a polymerase chain reaction assay we surveyed for the A and B group Wolbachia in 82 insect species from two temperate host-parasitoid communities (food webs) and a general collection of Lepidoptera caught at a light trap. One host-parasitoid community was based around leaf-mining Lepidoptera, and the other around Aphids. We found that: (i) 22.0% of insects sampled were infected with Wolbachia; and (ii) the prevalence and type (A or B) of Wolbachia infection differed significantly between communities and taxonomic groups. We obtained DNA sequences from the ftsZ gene for the group B Wolbachia found in six leaf-mining species and one of their parasitoids, as well as four of the Lepidoptera caught by a light trap. Taken together, the results of our survey and phylogenetic analyses of the sequence data suggest that host-parasitoid transfer of Wolbanchia is not the major route through which the species we have examined become infected. In addition, the Wolbachia strains observed in five leaf-mining species from the same genus were not closely related, indicating that transfer between species has not occurred due to a shared feeding niche or cospeciation.

Animals↗

PubMed1998

Paroxetine treatment of trichotillomania in an adolescent.

The authors present a case report involving an adolescent with trichotillomania who was treated with paroxetine. A significant reduction in symptoms was apparent after two weeks of treatment. Dose was gradually increased to 30 mg of paroxetine per day, which was well tolerated without any significant adverse events. The authors discuss potential treatment implications of this case.

Adolescent↗

PubMed1998

Testing for epistasis between deleterious mutations.

Determining the way in which deleterious mutations interact in their effects on fitness is crucial to numerous areas in population genetics and evolutionary biology. For example, if each additional mutation leads to a greater decrease in log fitness than the last (synergistic epistasis), then the evolution of sex and recombination may be favored to facilitate the elimination of deleterious mutations. However, there is a severe shortage of relevant data. Three relatively simple experimental methods to test for epistasis between deleterious mutations in haploid species have recently been proposed. These methods involve crossing individuals and examining the mean and/or skew in log fitness of the offspring and parents. The main aim of this paper is to formalize these methods, and determine the most effective way in which tests for epistasis could be carried out. We show that only one of these methods is likely to give useful results: crossing individuals that have very different numbers of deleterious mutations, and comparing the mean log fitness of the parents with that of their offspring. We also reconsider experimental data collected on Chlamydomonas moewussi using two of the three methods. Finally, we suggest how the test could be applied to diploid species.

Animals↗

PubMed1998

12-month outcome of patients with bipolar disorder following hospitalization for a manic or mixed episode.

OBJECTIVE: The authors studied the 12-month course of illness following hospitalization for a manic or mixed episode of bipolar disorder to identify potential outcome predictors. METHOD: They recruited 134 patients with DSM-III-R bipolar disorder who were consecutively admitted for the treatment of a manic or mixed episode. Diagnostic, symptomatic, and functional evaluations were obtained at the index hospitalization. Patients were reevaluated at 2, 6, and 12 months after discharge to assess syndromic, symptomatic, and functional outcome. Factors associated with outcome were identified by using multivariate analyses. RESULTS: During the 12-month follow-up period, there were no significant differences in outcome between patients with manic compared with mixed bipolar disorder. Although syndromic recovery occurred in 48% of the overall group, symptomatic recovery occurred in only 26% and functional recovery in only 24%. Predictors of syndromic recovery included shorter duration of illness and full treatment compliance. Medication treatment compliance was inversely associated with the presence of comorbid substance use disorders. Symptomatic and functional recovery occurred more rapidly and in a greater percentage of patients from higher social classes. CONCLUSIONS: A minority of patients with bipolar disorder achieved a favorable outcome in the year following hospitalization for a manic or mixed episode. Shorter duration of illness, higher social class, and treatment compliance were associated with higher rates of recovery and more rapid recovery.

Adolescent↗

PubMed1998

Course of psychiatric and substance abuse syndromes co-occurring with bipolar disorder after a first psychiatric hospitalization.

BACKGROUND: Patients with bipolar disorder frequently meet criteria for other psychiatric and substance abuse diagnoses. To clarify relationships among these disorders, the authors examined the course of syndromes co-occurring with bipolar disorder for 12 months after a first hospitalization. METHOD: Seventy-seven patients were recruited from consecutive inpatient admissions who met DSM-III-R criteria for bipolar disorder, manic or mixed with psychosis. The 12-month syndromal course of co-occurring DSM-III-R alcohol and drug abuse disorders, posttraumatic stress disorder (PTSD), obsessive-compulsive disorder (OCD), and other anxiety disorders were longitudinally recorded. RESULTS: The rates of all syndromes, except other anxiety disorders, were elevated. OCD demonstrated an interval course that frequently mirrored the course of the bipolar disorder. The courses of PTSD and substance abuse syndromes were separate from that of the bipolar disorder in many of those with both syndromes. Alcohol and drug abuse syndromes were strongly correlated. CONCLUSION: The obsessive-compulsive syndrome may represent an alternative expression of bipolar disorder in some patients. In contrast, PTSD appears to represent a truly separate disorder, which is possibly more prevalent in bipolar patients due to a shared risk factor. Substance abuse does not appear to simply result from attempts at self-medication or from the impulsivity of mania. These results suggest that future studies examining the course of syndromes co-occurring with bipolar disorder are warranted.

Adult↗

PubMed1998

Influence of rat strain on larval production by the parasitic nematode Strongyloides ratti.

The course of infection with Strongyloides ratti in a range of rat strains was assessed by monitoring the production of larvae. To our knowledge, this is the first such study of S. ratti using its natural host Rattus norvegicus. Host strain influenced the pattern of larval production. The results were qualitatively the same for 2 S. ratti lines of North American and Japanese origin.

Analysis of Variance↗

PubMed1997

Cerebrospinal fluid and plasma beta-endorphin in combat veterans with post-traumatic stress disorder.

Opioid-mediated analgesia develops in experimental animals following traumatic stress and increased opioid-mediated analgesia has been observed in combat veterans with post-traumatic stress disorder (PTSD). These observations have led to the hypothesis that increased central nervous system (CNS) opioidergic activity exists in patients with PTSD. However, direct CNS data on opioid peptide concentrations and dynamics in patients with PTSD are lacking. We withdrew cerebrospinal fluid (CSF) via a flexible, indwelling subarachnoid catheter over a 6-h period and determined hourly CSF concentrations of immunoreactive beta-endorphin (ir beta END) in 10 well-characterized combat veterans with PTSD and nine matched normal volunteers. Blood was simultaneously withdrawn to obtain plasma for ir beta END. PTSD symptom clusters, as measured by the CAPS, were correlated with neuroendocrine data. Mean CSF ir beta END was significantly greater in patients with PTSD compared with normals and there was a negative correlation between the ir beta END and PTSD intrusive and avoidant symptoms of PTSD. No intergroup difference between plasma ir beta END was found, nor was there a significant correlation between CSF and plasma ir beta END. Immunoreactive beta-lipotropin (ir beta LPH) and pro-opiomelanocortin (irPOMC), both precursors of beta END, were much more plentiful in human CSF than was beta-endorphin itself, as has been previously reported. It remains to be determined whether the increased CNS opioid concentrations predate traumatic stress, thereby conferring a vulnerability to dissociative states and PTSD itself, or result from the trauma. The negative correlation between CSF ir beta END and avoidant and intrusive symptoms suggests that CNS hypersecretion of opioids might constitute an adaptive response to traumatic experience. Poor correlation between CSF and plasma ir beta END limits use of plasma measures to assess CNS opioid activity.

Adrenocorticotropic Hormone↗

PubMed1997

Phenomenology of adolescent and adult mania in hospitalized patients with bipolar disorder.

OBJECTIVE: Although available data suggest that bipolar disorder most commonly begins in adolescence, it has often been underrecognized and misdiagnosed in this age group. The authors hypothesized that this might in part be because adolescent mania is phenomenologically different from adult mania. To test this hypothesis, they compared a cohort of adolescents hospitalized for acute mania with a group of hospitalized acutely manic adults. METHOD: The authors compared symptomatic differences between 40 adolescent (ages 12-18 years) and 88 adult (ages 19-45 years) bipolar patients hospitalized for acute mania. They also compared the two groups with respect to demographic characteristics, psychiatric comorbidity, family history, and short-term outcome. RESULTS: Compared with adults, adolescent patients displayed a significantly higher rate of mixed bipolar disorder and a significantly lower rate of psychotic features (by DSM-III-R criteria), as well as higher ratings for many depressive symptoms (including suicidality and depressed mood) and lower ratings for thought disorder and delusions. Adolescents also displayed a significantly lower rate of substance abuse and significantly higher rates of familial mood disorder and drug abuse or dependence. CONCLUSIONS: Significant differences were found in the phenomenology of adolescent and adult mania in this study. The reasons for these differences are not known. Possible explanations include artifact due to methodological limitations and differences between adolescents and adults in familial loading for mood or substance use disorders or in developmental or maturational stage.

Acute Disease↗

PubMed1997

Comparison of patients with early-, typical-, and late-onset affective psychosis.

OBJECTIVE: The authors compared the clinical characteristics and family history of patients with early-onset (before age 18), typical-onset (at 20-25 years), and late-onset (after age 35) affective psychosis at the time of first hospitalization. METHOD: Diagnostic, symptom, and family history information was obtained from 88 consecutively hospitalized patients. RESULTS: Major depression was more common in the late-onset group, and a family history of affective and substance abuse disorders was more common among the early-onset patients. Affective symptoms differed significantly among groups; specifically, early-onset patients had more energy, minimal sleep disruption, and greater suicidality, while typical-onset patients had more severe abnormal thought content. CONCLUSIONS: Among patients with affective psychosis, there may be heterogeneity of symptoms and family history associated with age at first hospitalization.

Adolescent↗

PubMed1997

The effects of race and information variance on disagreement between psychiatric emergency service and research diagnoses in first-episode psychosis.

BACKGROUND: Previously, we reported that patient race was associated with disagreement between research and clinical diagnoses. To extend this work, we studied whether disagreement was specifically due to associations of patient race with information or criterion variance. METHOD: Ninety-nine patients consecutively admitted through the University of Cincinnati Psychiatric Emergency Service (PES) for a first hospitalization for psychosis were evaluated using the Structured Clinical Interview for DSM-III-R. Diagnoses made in the PES were compared with those obtained from the structured interview. We examined the contributions of information variance and criterion variance to the association between race and diagnostic agreement of PES and research diagnoses. RESULTS: Agreement in PES and research diagnoses was present in only 42% of patients. Diagnostic agreement was less common in non-white patients than white patients, even after controlling for other sociodemographic and clinical variables. Information variance was the cause of diagnostic disagreement in 58% of cases and was associated with patient race. Criterion variance, occurring in 42% of cases, was not associated with race. CONCLUSION: Patient race may contribute to the diagnostic process in the psychiatric emergency service by influencing the information obtained from patients during clinical evaluations.

Emergency Services, Psychiatric↗