103 research outputs found

    Testosterone Therapy in Adult-Onset Testosterone Deficiency: Hematocrit and Hemoglobin Changes

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    Objective: Hematocrit (HCT)/hemoglobin (Hb) ratio in (%/g/dL) is around 3, with high fidelity between measured and derived Hb (applying the conversion using HCT) in various pathologies. We examined changes in HCT and Hb values and HCT/Hb, compared with baseline, in men with adult-onset testosterone deficiency (TD) given testosterone therapy (TTh). Materials and Methods: Data were analyzed from an observational, prospective registry study at various time points in 353 men with adult-onset TD receiving testosterone undecanoate (median follow-up: 105 months). After establishing baseline HCT/Hb, we compared (cf. baseline) changes in HCT, Hb, and HCT/Hb at 12, 48, 72, and 96 months. Regression analyses determined predictors of HCT and Hb change. Results: TTh was associated with ( p < 0.0001) increases in median HCT and Hb; 44% to 49% and 14.5 to 14.9 g/dL at final assessment, respectively. Regression analyses showed that HCT change was associated with baseline HCT and testosterone levels, while Hb change was associated with baseline Hb, HCT, and testosterone levels. In the total cohort and subgroups, HCT/Hb increased significantly at all time points ( p < 0.0001, cf. baseline) with over 90% of men demonstrating increases. Linear regression showed that the ratio of HCT change/Hb change (i.e., difference between HCT at the various time points and baseline value/difference between Hb at the various time points and baseline value), following TTh at each time point was higher than the baseline HCT/Hb ratio. Conclusion: HCT increase was greater than we anticipated from the established HCT/Hb of 3. We speculate that increased erythrocyte life span with associated higher Hb loss via vesiculation could account for our observation. This could have a bearing when using HbA1c as an indicator in men with adult-onset TD on TTh

    Testosterone Therapy: Increase in Hematocrit is Associated with Decreased Mortality

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    Objective: Testosterone therapy (TTh) may reduce morbidity/mortality in men with adult-onset testosterone deficiency (TD), though some cardiovascular safety concerns remain. Increased hematocrit (HCT), a recognized effect of therapy, may be associated with cardiovascular disease and mortality. We examined HCT change (Δ) in men prescribed/not prescribed testosterone, and associations with mortality. Methods: We analyzed data from a prospective registry study with adult-onset TD patients: 353 men given testosterone undecanoate (TU) and 384 opting against TTh. Change in HCT after 12, 48, 72, and 96 months of TU and at final assessment was compared (nonparametric tests). The association between baseline HCT, Δ HCT, and mortality was studied using logistic and Cox regression. Results: HCT increased significantly (median change at final assessment: +5.0%) in men on TTh. HCT was higher (p = 0.021, rank-sum test) in those alive than in those who died, although median values were identical (49.0%). Baseline HCT and Δ HCT were inversely associated with mortality after adjustment for age in both logistic and Cox regression models. Men with final HCT >49.0% (median) suffered lower mortality than men with HCT ≤49.0%. Conclusions: A median HCT increase of 5.0% was associated with TTh, mostly within 48 months of commencing therapy. An increase in HCT (up to 52.0% at final assessment) was independently associated with reduced mortality, indicating current guidelines using a HCT value of 54.0% as a threshold for management change are appropriate until further study

    Psychometric performance of the CAMPHOR and SF-36 in pulmonary hypertension

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    BACKGROUND: The Cambridge Pulmonary Hypertension Outcome Review (CAMPHOR) and the Medical Outcomes Study Short Form 36 (SF-36) are widely used to assess patient-reported outcome in individuals with pulmonary hypertension (PH). The aim of the study was to compare the psychometric properties of the two measures. METHODS: Participants were recruited from specialist PH centres in Australia and New Zealand. Participants completed the CAMPHOR and SF-36 at two time points two weeks apart. The SF-36 is a generic health status questionnaire consisting of 36 items split into 8 sections. The CAMPHOR is a PH-specific measure consisting of 3 scales; symptoms, activity limitations and needs-based QoL. The questionnaires were assessed for distributional properties (floor and ceiling effects), internal consistency (Cronbach's alpha), test-retest reliability and construct validity (scores by World Health Organisation functional classification). RESULTS: The sample comprised 65 participants (mean (SD) age = 57.2 (14.5) years; n(%) male = 14 (21.5%)). Most of the patients were in WHO class 2 (27.7%) and 3 (61.5%). High ceiling effects were observed for the SF-36 bodily pain, social functioning and role emotional domains. Test-retest reliability was poor for six of the eight SF-36 domains, indicating high levels of random measurement error. Three of the SF-36 domains did not distinguish between WHO classes. In contrast, all CAMPHOR scales exhibited good distributional properties, test retest reliability and distinguished between WHO functional classes. CONCLUSIONS: The CAMPHOR exhibited superior psychometric properties, compared with the SF-36, in the assessment of PH patient-reported outcome

    The Effect of Negative and Positive Emotionality on Associative Memory: An fMRI Study

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    In general, emotion is known to enhance memory processes. However, the effect of emotion on associative memory and the underling neural mechanisms remains largely unexplored. In this study, we explored brain activation during an associative memory task that involved the encoding and retrieval of word and face pairs. The word and face pairs consisted of either negative or positive words with neutral faces. Significant hippocampal activation was observed during both encoding and retrieval, regardless of whether the word was negative or positive. Negative and positive emotionality differentially affected the hemodynamic responses to encoding and retrieval in the amygdala, with increased responses during encoding negative word and face pairs. Furthermore, activation of the amygdala during encoding of negative word and neutral face pairs was inversely correlated with subsequent memory retrieval. These findings suggest that activation of the amygdala induced by negative emotion during encoding may disrupt associative memory performance

    Wild-type and mutant SOD1 share an aberrant conformation and a common pathogenic pathway in ALS.

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    Many mutations confer one or more toxic function(s) on copper/zinc superoxide dismutase 1 (SOD1) that impair motor neuron viability and cause familial amyotrophic lateral sclerosis (FALS). Using a conformation-specific antibody that detects misfolded SOD1 (C4F6), we found that oxidized wild-type SOD1 and mutant SOD1 share a conformational epitope that is not present in normal wild-type SOD1. In a subset of human sporadic ALS (SALS) cases, motor neurons in the lumbosacral spinal cord were markedly C4F6 immunoreactive, indicating that an aberrant wild-type SOD1 species was present. Recombinant, oxidized wild-type SOD1 and wild-type SOD1 immunopurified from SALS tissues inhibited kinesin-based fast axonal transport in a manner similar to that of FALS-linked mutant SOD1. Our findings suggest that wild-type SOD1 can be pathogenic in SALS and identify an SOD1-dependent pathogenic mechanism common to FALS and SALS

    Investigating Bacterial Sources of Toxicity as an Environmental Contributor to Dopaminergic Neurodegeneration

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    Parkinson disease (PD) involves progressive neurodegeneration, including loss of dopamine (DA) neurons from the substantia nigra. Select genes associated with rare familial forms of PD function in cellular pathways, such as the ubiquitin-proteasome system (UPS), involved in protein degradation. The misfolding and accumulation of proteins, such as α-synuclein, into inclusions termed Lewy Bodies represents a clinical hallmark of PD. Given the predominance of sporadic PD among patient populations, environmental toxins may induce the disease, although their nature is largely unknown. Thus, an unmet challenge surrounds the discovery of causal or contributory neurotoxic factors that could account for the prevalence of sporadic PD. Bacteria within the order Actinomycetales are renowned for their robust production of secondary metabolites and might represent unidentified sources of environmental exposures. Among these, the aerobic genera, Streptomyces, produce natural proteasome inhibitors that block protein degradation and may potentially damage DA neurons. Here we demonstrate that a metabolite produced by a common soil bacterium, S. venezuelae, caused DA neurodegeneration in the nematode, Caenorhabditis elegans, which increased as animals aged. This metabolite, which disrupts UPS function, caused gradual degeneration of all neuronal classes examined, however DA neurons were particularly vulnerable to exposure. The presence of DA exacerbated toxicity because neurodegeneration was attenuated in mutant nematodes depleted for tyrosine hydroxylase (TH), the rate-limiting enzyme in DA production. Strikingly, this factor caused dose-dependent death of human SH-SY5Y neuroblastoma cells, a dopaminergic line. Efforts to purify the toxic activity revealed that it is a highly stable, lipophilic, and chemically unique small molecule. Evidence of a robust neurotoxic factor that selectively impacts neuronal survival in a progressive yet moderate manner is consistent with the etiology of age-associated neurodegenerative diseases. Collectively, these data suggest the potential for exposures to the metabolites of specific common soil bacteria to possibly represent a contributory environmental component to PD

    Variability in Working Memory Performance Explained by Epistasis vs Polygenic Scores in the ZNF804A Pathway

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    Importance: We investigated the variation in neuropsychological function explained by risk alleles at the psychosis susceptibility gene ZNF804A and its interacting partners using single nucleotide polymorphisms (SNPs), polygenic scores, and epistatic analyses. Of particular importance was the relative contribution of the polygenic score vs epistasis in variation explained. Objectives To (1) assess the association between SNPs in ZNF804A and the ZNF804A polygenic score with measures of cognition in cases with psychosis and (2) assess whether epistasis within the ZNF804A pathway could explain additional variation above and beyond that explained by the polygenic score. Design, Setting, and Participants: Patients with psychosis (n = 424) were assessed in areas of cognitive ability impaired in schizophrenia including IQ, memory, attention, and social cognition. We used the Psychiatric GWAS Consortium 1 schizophrenia genome-wide association study to calculate a polygenic score based on identified risk variants within this genetic pathway. Cognitive measures significantly associated with the polygenic score were tested for an epistatic component using a training set (n = 170), which was used to develop linear regression models containing the polygenic score and 2-SNP interactions. The best-fitting models were tested for replication in 2 independent test sets of cases: (1) 170 individuals with schizophrenia or schizoaffective disorder and (2) 84 patients with broad psychosis (including bipolar disorder, major depressive disorder, and other psychosis). Main Outcomes and Measures: Participants completed a neuropsychological assessment battery designed to target the cognitive deficits of schizophrenia including general cognitive function, episodic memory, working memory, attentional control, and social cognition. Results: Higher polygenic scores were associated with poorer performance among patients on IQ, memory, and social cognition, explaining 1% to 3% of variation on these scores (range, P = .01 to .03). Using a narrow psychosis training set and independent test sets of narrow phenotype psychosis (schizophrenia and schizoaffective disorder), broad psychosis, and control participants (n = 89), the addition of 2 interaction terms containing 2 SNPs each increased the R2 for spatial working memory strategy in the independent psychosis test sets from 1.2% using the polygenic score only to 4.8% (P = .11 and .001, respectively) but did not explain additional variation in control participants. Conclusions and Relevance: These data support a role for the ZNF804A pathway in IQ, memory, and social cognition in cases. Furthermore, we showed that epistasis increases the variation explained above the contribution of the polygenic score
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