Peripheral inflammatory cytokines and motor symptoms in persons with Parkinson's disease

Background

Many of the motor symptoms of Parkinson's disease (PD) impact quality of life and are not fully ameliorated by current pharmacological and surgical treatments. A better understanding of the pathophysiology underlying these symptoms is needed. Previous research has suggested that inflammation may play a significant role in PD pathophysiology and progression, but there is limited research exploring how inflammation directly relates to motor symptoms in PD. Thus, the purpose of this study was to evaluate associations between peripheral immune inflammatory markers and motor symptoms of PD, specifically, tremor, bradykinesia, and postural and gait instability. We hypothesized that peripheral inflammatory cytokines would predict the severity of motor symptoms in persons with PD, and that there will be higher levels of peripheral inflammatory cytokine markers in persons with PD when compared to age-matched healthy older adults.

Methods

Twenty-six participants with PD and fourteen healthy older adults completed the study. For participants with PD, the motor section of the Unified Parkinson's Disease Rating Scale (UPDRS) was recorded and scored by two Movement Disorders Neurologists masked to the study. A blood sample was collected from both participants with PD and the healthy older adults. Through the MILLIPLEX® map High Sensitivity Human Cytokine Kit, key inflammation-related markers were analyzed (TNF-α, IFN-γ, IL-1β, IL-8, IL-2, IL-7, IL-5, IL-13, IL, 4, IL-10 IL-12p70, GM-CSF, and IL-6).

Results

Results revealed significantly higher levels of IL-6 in persons with PD when compared to healthy older adults (p ​= ​0.005). Moreover, results revealed that higher levels of IL-4 (p ​= ​0.011) and lower levels of IFNγ (p ​= ​0.003) significantly predicted more severe tremor in persons with PD. No other associations between the peripheral inflammation markers and other motor symptoms were observed.

Conclusions

Overall, these results are consistent with a growing body of literature that implicates inflammatory cytokines in the PD, and further suggests that inflammatory cytokines, or lack thereof, may be associated with tremor in persons with PD.

The validity of surface EMG of extra-diaphragmatic muscles in assessing respiratory responses during mechanical ventilation: A systematic review

PURPOSE

Evidence supporting the utilization of surface EMG (sEMG) of extra-diaphragmatic muscles for monitoring of mechanical ventilation (MV) assistance is unclear. The purpose of this review was to assess the quality of literature available on using extra-diaphragmatic sEMG as an assessment technique of respiratory responses during MV.

METHODS

Studies using sEMG of extra-diaphragmatic respiratory muscles during MV were selected by two independent researchers after performing a database search of PubMed, CINAHL, GOOGLE SCHOLAR. Exclusion criteria were studies of patients with neuromuscular disorders, receiving neuromuscular blocking agents, receiving non-invasive MV, using needle EMG, and studies written in languages other than English. Quality of identified studies was assessed with the Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2). This study is registered with PROSPERO, number (CRD42018081341).

RESULTS

596 references were identified. Of the identified studies, 7 studies were included in the review. Findings demonstrate that sEMG of extra-diaphragmatic muscle activity is a valid and applicable tool to evaluate mechanical loading/unloading of respiratory muscles and respiratory drive or sensation. However, the quality of literature supporting sEMG as monitoring tool of respiratory responses were characterized by a high and unclear risk of bias.

CONCLUSIONS

Although it appears to be a valid and applicable tool, there is a scarcity of literature that directly demonstrates the diagnostic accuracy of sEMG of extra-diaphragmatic muscles in monitoring respiratory mechanics and respiratory drive or sensation during MV assistance across wide populations and conditions.

Narrative approach in understanding the drivers for resilience of military combat medics

INTRODUCTION

Qualitative insights may demonstrate how combat medics (CM) deal with stressors and identify how resilience can potentially develop. Yet, qualitative research is scant in comparison to the many quantitative studies of health outcomes associated with military service.

METHOD

Semistructured qualitative interviews were used to collect personal narratives of US Army CMs who had previously served in Iraq or Afghanistan.

RESULTS

Thematic analysis revealed three key driving forces for how resilience develops in the context of combat and war. The first was patriotism, which captures loyalty and full commitment to the military and its missions. The second was commitment to their family, reflecting the balance of responsibility to family of origin with the obligation one feels towards their military family. The last driving force was faith, or the drive to reach towards the transcendent to provide a moral compass and develop empathy in the face of difficult situations.

CONCLUSIONS

An individual's commitment to country, military family and faith strengthens their resilience, and this can be used to inform future research efforts as well as current clinical practice.

Mitochondria-focused gene expression profile reveals common pathways and CPT1B dysregulation in both rodent stress model and human subjects with PTSD

Posttraumatic stress disorder (PTSD), a trauma-related mental disorder, is associated with mitochondrial dysfunction in the brain. However, the biologic approach to identifying the mitochondria-focused genes underlying the pathogenesis of PTSD is still in its infancy. Previous research, using a human mitochondria-focused cDNA microarray (hMitChip3) found dysregulated mitochondria-focused genes present in postmortem brains of PTSD patients, indicating that those genes might be PTSD-related biomarkers. To further test this idea, this research examines profiles of mitochondria-focused gene expression in the stressed-rodent model (inescapable tail shock in rats), which shows characteristics of PTSD-like behaviors and also in the blood of subjects with PTSD. This study found that 34 mitochondria-focused genes being upregulated in stressed-rat amygdala. Ten common pathways, including fatty acid metabolism and peroxisome proliferator-activated receptors (PPAR) pathways were dysregulated in the amygdala of the stressed rats. Carnitine palmitoyltransferase 1B (CPT1B), an enzyme in the fatty acid metabolism and PPAR pathways, was significantly over-expressed in the amygdala (P < 0.007) and in the blood (P < 0.01) of stressed rats compared with non-stressed controls. In human subjects with (n = 28) or without PTSD (n = 31), significant over-expression of CPT1B in PTSD was also observed in the two common dysregulated pathways: fatty acid metabolism (P = 0.0027, false discovery rate (FDR) = 0.043) and PPAR (P = 0.006, FDR = 0.08). Quantitative real-time polymerase chain reaction validated the microarray findings and the CPT1B result. These findings indicate that blood can be used as a specimen in the search for PTSD biomarkers in fatty acid metabolism and PPAR pathways, and, in addition, that CPT1B may contribute to the pathology of PTSD.

Lack of genotoxicity due to foamy virus vector integration in human iPSCs

Integrating vectors can lead to the dysregulation of nearby chromosomal genes, with important consequences for clinical trials and cellular engineering. This includes the retroviral and lentiviral vectors commonly used for deriving induced pluripotent stem cells (iPSCs). We previously used integrating foamy virus (FV) vectors expressing OCT4, SOX2, MYC, and KLF4 to reprogram osteogenesis imperfecta mesenchymal stem cells (MSCs). Here we have studied the effects of 10 FV vector proviruses on neighboring gene expression in four iPSC lines and their corresponding iPSC-derived mesenchymal stem cells (iMSCs). Gene expression profiles in these iPSC lines showed that none of the 38 genes within 300 kb up- or downstream of integrated proviruses had a significant difference in mRNA levels, including 5 genes with proviruses in their transcription units. In the iMSCs derived from these iPSCs, the same type of analysis showed a single dysregulated transcript out of 46 genes found near proviruses. This frequency of dysregulation was similar to that of genes lacking nearby proviruses, so it may have been due to interclonal variation and/or measurement inaccuracies. While the number of integration sites examined in this paper is limited, our results suggest that integrated FV proviruses do not impact the expression of chromosomal genes in pluripotent human stem cells or their differentiated derivatives. This interpretation is consistent with previous reports that FV vectors have minimal genotoxicity, even when integrating near or within genes.

Chromatin structure of two genomic sites for targeted transgene integration in induced pluripotent stem cells and hematopoietic stem cells

Achieving transgene integration into preselected genomic sites is currently one of the central tasks in stem cell gene therapy. A strategy to mediate such targeted integration involves site specific endonucleases. Two genomic sites within the MBS85 and CCR5 genes [AAVS1 and CCR5 zinc finger nuclease (CCR5-ZFN) site, respectively] have recently been suggested as potential target regions for integration as their disruption has no functional consequence. We hypothesized that efficient transgene integration maybe affected by DNA accessibility of endonucleases and therefore studied the transcriptional and chromatin status of the AAVS1 and CCR5 sites in eight human induced pluripotent stem (iPS) cell lines and pooled CD34+ hematopoietic stem cells. Matrixchromatin immunoprecipitation (ChIP) assays demonstrated that the CCR5 site and surrounding regions possessed a predominantly closed chromatin configuration consistent with its transcriptionally inactivity in these cell types. In contrast, the AAVS1 site was located within a transcriptionally active region and exhibited an open chromatin configuration in both iPS cells and hematopoietic stem cells. To show that the AAVS1 site is readily amendable to genome modification, we expressed Rep78, an AAV2-derived protein with AAVS1-specific endonuclease activity, in iPS cells after adenoviral gene transfer. We showed that Rep78 efficiently associated with the AAVS1 site and triggered genome modifications within this site. On the other hand, binding to and modification of the CCR5-ZFN site by a zinc-finger nuclease was relatively inefficient. Our data suggest a critical influence of chromatin structure on efficacy of site-specific endonucleases used for genome editing.

Dual transgene expression by foamy virus vectors carrying an endogenous bidirectional promoter

Several gene therapy applications require the transfer and simultaneous expression of multiple genes in the same cell. In this study, we analyzed the potential for coordinated expression of an endogenous bidirectional promoter located on chromosome X, which controls the expression of the heterogeneous nuclear ribonucleoprotein H2 (HNRNPH2) and alpha-galactosidase (GLA) genes. The promoter was cloned in both transcriptional orientations in a foamy virus (FV) vector backbone, whereas the enhanced green fluorescent protein (EGFP) and low-affinity nerve growth factor receptor (DeltaLNGFR) reporter genes were cloned in the 5'-3' and 3'-5' transcriptional orientations, respectively. In all the cell lines tested, both vectors showed high levels of transgene coexpression that reached 76% of total positive cells (range from 76 to 18%). Comparison of EGFP and DeltaNGFR levels revealed that the side of the promoter that drives the expression of the HNRNPH2 gene in the genome was stronger and in accordance to its in situ activity. When tested with CD34(+) cells, transgene coexpression reached 35.3% of all positive cells in progenitor assays and 16.8% of all positive cells after transplantation in NOD/severe combined immunodeficient mice. In summary, we show that the endogenous promoter used in this study holds bidirectional activity in the context of FV vectors and can be used in gene therapy applications requiring synchronized expression of two genes.

Aerobic exercise, but not flexibility/resistance exercise, reduces serum IL-18, CRP, and IL-6 independent of beta-blockers, BMI, and psychosocial factors in older adults

Increased serum levels of inflammatory mediators have been associated with numerous disease states including atherosclerosis, Type II diabetes, hypertension, depression, and overall mortality. We hypothesized that a long-term exercise intervention among older adults would reduce serum inflammatory cytokines, and this reduction would be mediated, in part, by improvements in psychosocial factors and/or by beta-adrenergic receptor mechanisms. Adults age 64 were randomly assigned to either an aerobic exercise treatment (CARDIO) or a flexibility/strength exercise treatment (FLEX) 3 days/week, 45 min/day for 10 months. A subgroup of subjects treated with non-selective beta(1)beta(2) adrenergic antagonists were included to evaluate the potential role of beta-adrenergic receptor adaptations as mediators of an exercise-induced change in inflammation. The inflammatory mediators [C-reactive protein (CRP), IL-6, tumor necrosis factor (TNF)-alpha, and IL-18] and the psychosocial factors (depression, perceived stress, optimism, sense of coherence, and social support) were measured pre- and post-intervention. The CARDIO treatment resulted in significant reductions in serum CRP, IL-6, and IL-18 compared to the FLEX treatment (significant treatment x time interaction, p<.05), whereas TNFalpha declined in both groups (main effect of time, p=.001). However, several psychosocial factors (depression, optimism, and sense of coherence) improved in both groups suggesting that the reduction of CRP, IL-6, and IL-18 in the CARDIO group was not mediated by improvements in psychosocial scores. With respect to the potential role of beta-adrenergic receptors, both CARDIO subjects treated with beta-adrenergic antagonists and those who were not treated with those medications demonstrated similar reductions in serum CRP, IL-6, IL-18, and TNFalpha. In summary, we have observed that an aerobic exercise intervention can significantly reduce serum inflammatory mediators, but beta-adrenergic receptors and psychosocial factors do not appear to be involved.

The exercise-induced enhancement of influenza immunity is mediated in part by improvements in psychosocial factors in older adults

The primary goal of this study was to determine whether exercise-associated improvements of the immune response to influenza vaccination were mediated by improvements in psychosocial factors in older adults. At baseline, prior to the exercise intervention, older adult participants were immunized with influenza vaccine. Blood samples collected pre-immunization, 1, 4, and 12 weeks post-immunization were analyzed for anti-influenza antibody, whereas influenza-specific cytokine (IFNgamma) was evaluated at 1 week post-immunization. Depression and sense of coherence were measured pre-immunization. Four weeks post-immunization, participants were randomly assigned to either an aerobic exercise group (n=14) or a control group (n=14). After a 10-month exercise intervention, the immunization, blood collections, and psychosocial measures were repeated. At the post-intervention evaluation, exercise participants had improved scores on depression and sense of coherence. Also post-intervention, exercise participants had a greater increase in antibody and IFNgamma production. After controlling for the effect of both psychosocial measures, the exercise treatment remained significant with respect to antibody titer suggesting that the increases in antibody were not mediated by improvement in the psychosocial factors. In contrast, the enhancement of IFNgamma appeared to be mediated at least in part by the psychosocial factors. After controlling for psychosocial factors, exercise treatment was no longer significantly related to the change in IFNgamma. Taken together, our findings may suggest that the mechanism(s) of exercise-induced improvement in immunocompetence involve both physiological and psychological pathways.

The hypocholesterolemic agent LY295427 reverses suppression of sterol regulatory element-binding protein processing mediated by oxysterols

The sterol LY295427 reduces plasma cholesterol levels in animals by increasing the expression of hepatic low density lipoprotein (LDL) receptors. Here we trace the hypocholesterolemic activity of LY295427 to an ability to reverse oxysterol-mediated suppression of sterol regulatory element-binding protein (SREBP) processing. Micromolar concentrations of LY295427 induced the metabolism of LDL in oxysterol-treated cultured cells and inhibited the stimulation of cholesteryl ester synthesis mediated by oxysterols. cDNA microarray and RNA blotting experiments revealed that LY295427 increased levels of the LDL receptor mRNA and those of other SREBP target genes. The compound stimulated the accumulation of SREBPs in the nuclei of cells grown in the presence of oxysterols within 4-6 h of addition to the medium. Induction required components of the normal SREBP-processing pathway, including the SREBP cleavage-activating protein and the Site 1 protease. LY295427 overcame the suppression of SREBP processing mediated by several oxysterols but not by LDL-derived cholesterol. We conclude that LY295427 achieves a therapeutically desirable end point by an unique mechanism of action.

On the turnover of brain cholesterol in patients with Alzheimer's disease. Abnormal induction of the cholesterol-catabolic enzyme CYP46 in glial cells

Evidence is accumulating for a link between cerebral cholesterol metabolism and Alzheimer's disease (AD). Here we focus on a possible relationship between AD and a newly discovered mechanism for cholesterol efflux from the brain, involving conversion of brain cholesterol into 24S-hydroxycholesterol by the neuronal oxidative enzyme CYP46. There was a marked difference in the distribution of CYP46 in brains of control and AD patients. The neuronal cells were less stained in AD brains than in controls while marked positive staining was found in glial cells in AD but not in controls. The dynamic changes in the mechanisms for cholesterol efflux from the brain are of interest in relation to the link between brain cholesterol and amyloid beta-protein in AD.

Genetic analysis of intestinal cholesterol absorption in inbred mice

A genetic mapping strategy was employed to identify chromosomal regions harboring genes that influence the absorption of intestinal cholesterol in the mouse. Analysis of seven inbred strains of male mice (129P3, AKR, BALB/c, C3H/He, C57BL/6, DBA/2, and SJL, all from Jackson Laboratories) revealed substantial differences in their abilities to absorb a bolus of cholesterol delivered by gavage. Crosses between high (AKR, 129) and low (DBA/2, SJL) absorbing strains revealed evidence for the presence of dominant genes that increase and decrease cholesterol absorption. Backcrosses between F1 offspring and parental strains (DBA/2xAKD2F1 and 129xSJL129F1) followed by linkage analyses revealed four quantitative trait loci that influenced cholesterol absorption. Analyses of recombinant inbred strains identified an additional three loci affecting this phenotype. These seven quantitative trait loci, which map to different chromosomes and are termed Cholesterol absorption 1-7 (Chab1-7) loci, together influence the absorption of intestinal cholesterol in mice and are likely to be involved in different steps of this complex pathway.

Unexpected virilization in male mice lacking steroid 5 alpha-reductase enzymes

Mice lacking steroid 5 alpha-reductase 1 and 2 were produced by gene targeting and breeding. Male mice without 5 alpha-reductase 2 or without both enzymes had fully formed internal and external genitalia and were fertile, but had smaller prostates and seminal vesicles than controls. T accumulated to high levels in the reproductive tissues of the mutant mice. DHT administration increased seminal vesicle and coagulating gland weights in mice deficient in 5 alpha-reductase 2 and increased the weights of the prostate, seminal vesicle, and coagulating gland in animals deficient in both enzymes. An inhibitor of both 5 alpha-reductases (GI 208335X) decreased prostate and coagulating gland weights of control mice, but had no effect in those lacking 5 alpha-reductase 1 and 2. Castration reduced the sizes of these tissues in animals of all genotypes. Androgen-dependent gene expression was decreased in the seminal vesicles of mice lacking one or more 5 alpha-reductases and was restored by administration of T or DHT. Female mice missing both enzymes exhibited parturition and fecundity defects similar to those of animals without 5 alpha-reductase 1. We conclude that T is the only androgen required for differentiation of the male urogenital tract in mice and that the synthesis of DHT serves largely as a signal amplification mechanism.

Genetic analysis of cholesterol accumulation in inbred mice

Genetic linkage analysis in the laboratory mouse identified chromosomal regions containing genes that contribute to cholesterol accumulation in the liver and plasma. Comparisons between five inbred strains of mice obtained from the Jackson Laboratory (DBA/2, AKR, C57BL/6, SJL, and 129P3) revealed a direct correlation between intestinal cholesterol absorption and susceptibility to diet-induced hypercholesterolemia. This correlation was lost in the F1 generation arising from crosses between high- and low-absorbing strains. Linkage analyses in AKxD recombinant inbred strains and 129xSJL129F1 N2 backcross mice identified four quantitative trait loci (QTL) that influenced Liver cholesterol accumulation (Lcho1-4) and one locus that affected Plasma cholesterol accumulation (Pcho1). These loci map to five chromosomes and, with one exception, are different from the seven QTL identified previously that influence intestinal cholesterol absorption. We conclude that a large number of genes affects the amount of cholesterol absorbed in the small intestine and its accumulation in the liver and plasma of inbred mice.

Comparisons of marriage and family therapists, psychologists, psychiatrists, and social workers on job-related measures and reactions to managed care in Iowa

This study compares marriage and family therapists (MFTs) to psychologists, psychiatrists, and social workers on job-related measures, such as job autonomy, job satisfaction, burnout, and intention to stay in their present position, as well as on reactions to a managed care initiative in the state of Iowa. Findings indicate that MFTs scored significantly lower than other practitioners on job autonomy and intention to stay in their present position, but there were no differences in job satisfaction or burnout. Marital and family therapists also reported less dissatisfaction with the managed care initiative than psychiatrists, although virtually all practitioners were dissatisfied with the managed-care program. These findings indicate some dissatisfaction within the MFT profession and may be relevant to practitioners seeking to change or expand their practice, as well as to the needs of MFTs in their training programs.

Alternate pathways of bile acid synthesis in the cholesterol 7alpha-hydroxylase knockout mouse are not upregulated by either cholesterol or cholestyramine feeding

Bile acids are synthesized via the classic pathway initiated by cholesterol 7alpha-hydroxylase (CYP7A1), and via alternate pathways, one of which is initiated by sterol 27-hydroxylase (CYP27). These studies used mice lacking cholesterol 7alpha-hydroxylase (Cyp7a1(-/-)) to establish whether the loss of the classic pathway affected cholesterol homeostasis differently in males and females, and to determine if the rate of bile acid synthesis via alternate pathways was responsive to changes in the enterohepatic flux of cholesterol and bile acids. In both the Cyp7a1(-/-) males and females, the basal rate of bile acid synthesis was only half of that in matching Cyp7a1(+/+) animals. Although bile acid pool size contracted markedly in all the Cyp7a1(-/-) mice, the female Cyp7a1(-/-) mice maintained a larger, more cholic acid-rich pool than their male counterparts. Intestinal cholesterol absorption in the Cyp7a1(-/-) males fell from 46% to 3%, and in the matching females from 58% to 17%. Bile acid synthesis in Cyp7a1(+/+) males and females was increased 2-fold by cholesterol feeding, and 4-fold by cholestyramine treatment, but was not changed in matching Cyp7a1(-/-) mice by either of these manipulations. In the Cyp7a1(-/-) mice fed cholesterol, hepatic cholesterol concentrations increased only marginally in the males, but rose almost 3-fold in the females. CYP7A1 activity and mRNA levels were greater in females than in males, and were increased by cholesterol feeding in both sexes. CYP27 activity and mRNA levels did not vary as a function of CYP7A1 genotype, gender, or dietary cholesterol intake. We conclude that in the mouse the rate of bile acid synthesis via alternative pathways is unresponsive to changes in the enterohepatic flux of cholesterol and bile acid, and that factors governing gender-related differences in bile acid synthesis, pool size, and pool composition play an important role in determining the impact of CYP7A1 deficiency on cholesterol homeostasis in this species.

Gene transfer into murine hematopoietic stem cells with helper-free foamy virus vectors

Gene transfer into hematopoietic stem cells (HSCs) is an ideal treatment strategy for many genetic and hematologic diseases. However, progress has been limited by the low HSC transduction rates obtained with retroviral vectors based on murine leukemia viruses. This study examined the potential of vectors derived from the nonpathogenic human foamy virus (HFV) to transduce human CD34(+) cells and murine HSCs. More than 80% of human hematopoietic progenitors present in CD34(+) cell preparations derived from cord blood were transduced by a single overnight exposure to HFV vector stocks. Mice that received transduced bone marrow cells expressed the vector-encoded transgene long term in all major hematopoietic cell lineages and in over 50% of cells in some animals. Secondary bone marrow transplants and integration site analysis confirmed that gene transfer occurred at the stem cell level. Transgene silencing was not observed. Thus vectors based on foamy viruses represent a promising approach for HSC gene therapy. (Blood. 2001;98:604-609)

Introduction of single base substitutions at homologous chromosomal sequences by adeno-associated virus vectors

Adeno-associated virus (AAV) vectors can modify homologous chromosomal sequences at high rates. This gene targeting transduction pathway is distinct from the integrating and episomal pathways used in gene addition approaches. In previous studies, AAV vectors were used to introduce small insertion and deletion mutations at homologous chromosomal loci. Here we show that AAV-mediated gene targeting can also be used to introduce all possible types of single base substitution mutations at the endogenous single-copy hypoxanthine phosphoribosyl transferase locus. Southern blot and sequence analysis showed that the point mutations were introduced with high fidelity. We also show that AAV vectors can repair chromosomal alkaline phosphatase genes containing point mutations. Our results suggest that AAV vectors can be used to introduce single base substitutions at high frequencies in normal human cells, including the correction of point mutations responsible for genetic diseases.

Oxysterol biosynthetic enzymes

Oxysterols, herein defined as derivatives of cholesterol with a hydroxyl group on the side chain, play several roles in lipid metabolism. Members of this class regulate the expression of genes that participate in both sterol and fat metabolism, serve as substrates for the synthesis of bile acids, and are intermediates in the transfer of sterols from the periphery to the liver. Three abundant naturally occurring oxysterols are 24-hydroxycholesterol, 25-hydroxycholesterol, and 27-hydroxycholesterol. The cholesterol hydroxylase enzymes that synthesize each of these have been isolated over the last several years and their study has produced insight into the biology of oxysterols. This article focuses on the properties of these enzymes.

Disruption of the sterol 27-hydroxylase gene in mice results in hepatomegaly and hypertriglyceridemia. Reversal by cholic acid feeding

Sterol 27-hydroxylase (CYP27) participates in the conversion of cholesterol to bile acids. We examined lipid metabolism in mice lacking the Cyp27 gene. On normal rodent chow, Cyp27(-/-) mice have 40% larger livers, 45% larger adrenals, 2-fold higher hepatic and plasma triacylglycerol concentrations, a 70% higher rate of hepatic fatty acid synthesis, and a 70% increase in the ratio of oleic to stearic acid in the liver versus Cyp27(+/+) controls. In Cyp27(-/-) mice, cholesterol 7alpha-hydroxylase activity is increased 5-fold, but bile acid synthesis and pool size are 47 and 27%, respectively, of those in Cyp27(+/+) mice. Intestinal cholesterol absorption decreases from 54 to 4% in knockout mice, while fecal neutral sterol excretion increases 2.5-fold. A compensatory 2.5-fold increase in whole body cholesterol synthesis occurs in Cyp27(-/-) mice, principally in liver, adrenal, small intestine, lung, and spleen. The mRNA for the cholesterogenic transcription factor sterol regulatory element-binding protein-2 (SREBP-2) and mRNAs for SREBP-2-regulated cholesterol biosynthetic genes are elevated in livers of mutant mice. In addition, the mRNAs encoding the lipogenic transcription factor SREBP-1 and SREBP-1-regulated monounsaturated fatty acid biosynthetic enzymes are also increased. Hepatic synthesis of fatty acids and accumulation of triacylglycerols increases in Cyp27(-/-) mice and is associated with hypertriglyceridemia. Cholic acid feeding reverses hepatomegaly and hypertriglyceridemia but not adrenomegaly in Cyp27(-/-) mice. These studies confirm the importance of CYP27 in bile acid synthesis and they reveal an unexpected function of the enzyme in triacylglycerol metabolism.

Self-esteem, self-serving cognitions, and health risk behavior

The current article reviews prospective and experimental research on the relation between self-esteem and perceptions of vulnerability. These studies demonstrate that individuals with high self-esteem who engage in risk behavior often utilize a variety of self-serving cognitive strategies that protect them from fully acknowledging their vulnerability to the potential negative consequences of their behavior; e.g., they minimize their estimates of personal risk and overestimate the prevalence of the risk behavior among their peers. The article also provides data on an additional self-serving cognitive strategy employed by adolescents with high self-esteem--alteration of perceptions of others' reactions to their own risk behavior. Finally, the article reviews the emerging literature on the relation between these cognitive strategies and maladaptive health behavior, and proposes that whether these strategies are maladaptive depends on the nature of the threat and the availability of opportunities to engage in compensatory self-enhancement.

Direct and moderating effects of community context on the psychological well-being of African American women

The effects of community characteristics on well-being were examined among 709 African American women. Direct and moderating effects of neighborhood characteristics on distress were tested. Aggregate-level ratings of neighborhood cohesion and disorder were significantly related to distress, although the relation between cohesion and distress became nonsignificant when individual risk factors were statistically controlled. Aggregate-level neighborhood variables interacted significantly with individual risk and resource variables in the prediction of distress, consistent with trait-situation interaction theories (D. Magnusson & N. S. Endler, 1977). Community cohesion intensified the benefits of a positive life outlook. Community disorder intensified both the benefits of personal resources and the detrimental effects of personal risk factors. Results showed evidence of resilience among African American women.

The bile acid synthetic gene 3beta-hydroxy-Delta(5)-C(27)-steroid oxidoreductase is mutated in progressive intrahepatic cholestasis

We used expression cloning to isolate cDNAs encoding a microsomal 3beta-hydroxy-Delta(5)-C(27)-steroid oxidoreductase (C(27) 3beta-HSD) that is expressed predominantly in the liver. The predicted product shares 34% sequence identity with the C(19) and C(21) 3beta-HSD enzymes, which participate in steroid hormone metabolism. When transfected into cultured cells, the cloned C(27) 3beta-HSD cDNA encodes an enzyme that is active against four 7alpha-hydroxylated sterols, indicating that a single C(27) 3beta-HSD enzyme can participate in all known pathways of bile acid synthesis. The expressed enzyme did not metabolize several different C(19/21) steroids as substrates. The levels of hepatic C(27) 3beta-HSD mRNA in the mouse are not sexually dimorphic and do not change in response to dietary cholesterol or to changes in bile acid pool size. The corresponding human gene on chromosome 16p11.2-12 contains six exons and spans 3 kb of DNA, and we identified a 2-bp deletion in the C27 3beta-HSD gene of a patient with neonatal progressive intrahepatic cholestasis. This mutation eliminates the activity of the enzyme in transfected cells. These findings establish the central role of C(27) 3beta-HSD in the biosynthesis of bile acids and provide molecular tools for the diagnosis of a third type of neonatal progressive intrahepatic cholestasis associated with impaired bile acid synthesis.

Disruption of the oxysterol 7alpha-hydroxylase gene in mice

Mice without oxysterol 7alpha-hydroxylase, an enzyme of the alternate bile acid synthesis pathway with a sexually dimorphic expression pattern, were constructed by the introduction of a null mutation at the Cyp7b1 locus. Animals heterozygous (Cyp7b1(+/-)) and homozygous (Cyp7b1(-/-)) for this mutation were grossly indistinguishable from wild-type mice. Plasma and tissue levels of 25- and 27-hydroxycholesterol, two oxysterol substrates of this enzyme with potent regulatory actions in cultured cells, were markedly elevated in Cyp7b1(-/-) knockout animals. Parameters of bile acid metabolism as well as plasma cholesterol and triglyceride levels in male and female Cyp7b1(-/-) mice were normal. The cholesterol contents of major tissues were not altered. In vivo sterol biosynthetic rates were unaffected in multiple tissues with the exception of the male kidney, which showed a approximately 40% decrease in de novo synthesis versus controls. We conclude that the major physiological role of the CYP7B1 oxysterol 7alpha-hydroxylase is to metabolize 25- and 27-hydroxycholesterol and that loss of this enzyme in the liver is compensated for by increases in the synthesis of bile acids by other pathways. A failure to catabolize oxysterols in the male kidney may lead to a decrease in de novo sterol synthesis.

Expression cloning of an oxysterol 7alpha-hydroxylase selective for 24-hydroxycholesterol

The synthesis of 7alpha-hydroxylated bile acids from oxysterols requires an oxysterol 7alpha-hydroxylase encoded by the Cyp7b1 locus. As expected, mice deficient in this enzyme have elevated plasma and tissue levels of 25- and 27-hydroxycholesterol; however, levels of another major oxysterol, 24-hydroxycholesterol, are not increased in these mice, suggesting the presence of another oxysterol 7alpha-hydroxylase. Here, we describe the cloning and characterization of murine and human cDNAs and genes that encode a second oxysterol 7alpha-hydroxylase. The genes contain 12 exons and are located on chromosome 6 in the human (CYP39A1 locus) and in a syntenic position on chromosome 17 in the mouse (Cyp39a1 locus). CYP39A1 is a microsomal cytochrome P450 enzyme that has preference for 24-hydroxycholesterol and is expressed in the liver. The levels of hepatic CYP39A1 mRNA do not change in response to dietary cholesterol, bile acids, or a bile acid-binding resin, unlike those encoding other sterol 7alpha-hydroxylases. Hepatic CYP39A1 expression is sexually dimorphic (female > male), which is opposite that of CYP7B1 (male > female). We conclude that oxysterol 7alpha-hydroxylases with different substrate specificities exist in mice and humans and that sexually dimorphic expression patterns of these enzymes in the mouse may underlie differences in bile acid metabolism between the sexes.

Blood cholesterol screening influence of fasting state on cholesterol results and management decisions

OBJECTIVE

To compare fasting and nonfasting total and high-density lipoprotein (HDL) cholesterol values in adults and to determine how closely classification into risk groups for coronary heart disease based on nonfasting blood tests compares with classification based on fasting studies.

DESIGN

Cross-sectional study.

SETTING

A community hospital general internal medicine clinic.

PATIENTS

One hundred eighty-one patients at least 20 years of age receiving medical care at a community hospital general internal medicine clinic.

INTERVENTIONS

Total and HDL cholesterol levels were measured twice in each patient within 7 days, once while not fasting and once after a minimum 12-hour fast.

MEASUREMENTS AND MAIN RESULTS

Fasting and nonfasting total and HDL cholesterol values were compared, patients were classified into desirable, borderline-high, and high cholesterol groups on the basis of fasting and nonfasting blood studies. There were small, statistically significant but clinically insignificant differences in fasting and nonfasting results for total cholesterol. Nonfasting HDL cholesterol levels were similar to fasting HDL levels. The agreement in classification of patients into desirable and high-cholesterol groups between fasting and non-fasting blood testing was 86.7% and 89.5%, respectively. In the borderline-high group, for whom levels of HDL cholesterol are important in determining subsequent management, there was 95% agreement between fasting and nonfasting HDL cholesterol results. Only a small fraction of the patients were classified into lower-risk groups by the nonfasting assessment, creating the potential for less-rigorous monitoring and treatment of their cholesterol status than if fasting results were utilized. These findings were confirmed in this study also for the subgroups of men aged 35 years and older and women aged 45 years and older.

CONCLUSIONS

Screening nonfasting adults for total and HDL cholesterol is appropriate for making decisions about primary prevention of coronary heart disease.

Design and packaging of adeno-associated virus gene targeting vectors

Adeno-associated virus (AAV) vectors can transduce cells by several mechanisms, including (i) gene addition by chromosomal integration or episomal transgene expression or (ii) gene targeting by modification of homologous chromosomal sequences. The latter process can be used to correct a variety of mutations in chromosomal genes with high fidelity and specificity. In this study, we used retroviral vectors to introduce mutant alkaline phosphatase reporter genes into normal human cells and subsequently corrected these mutations with AAV gene targeting vectors. We find that increasing the length of homology between the AAV vector and the target locus improves gene correction rates, as does positioning the mutation to be corrected in the center of the AAV vector genome. AAV-mediated gene targeting increases with time and multiplicity of infection, similar to AAV-mediated gene addition. However, in contrast to gene addition, genotoxic stress did not affect gene targeting rates, suggesting that different cellular factors are involved. In the course of these studies, we found that (i) vector genomes less than half of wild-type size could be packaged as monomers or dimers and (ii) packaged dimers consist of inverted repeats with covalently closed hairpins at either end. These studies should prove helpful in designing AAV gene targeting vectors for basic research or gene therapy.

Repeat transduction in the mouse lung by using adeno-associated virus vectors with different serotypes

Vectors derived from adeno-associated virus type 2 (AAV2) promote gene transfer and expression in the lung; however, we have found that while gene expression can persist for at least 8 months in mice, it was reduced dramatically in rabbits over a period of 2 months. The efficiency and persistence of AAV2-mediated gene expression in the human lung have yet to be determined, but it seems likely that readministration will be necessary over the lifetime of an individual. Unfortunately, we have found that transduction by a second administration of an AAV2 vector is blocked, presumably due to neutralizing antibodies generated in response to the primary vector exposure. Here, we have explored the use of AAV2 vectors pseudotyped with capsid proteins from AAV serotypes 2, 3, and 6 for readministration in the mouse lung. We found that an AAV6 vector transduced airway epithelial and alveolar cells in the lung at rates that were at least as high as those of AAV2 pseudotype vectors, while transduction rates mediated by AAV3 were much lower. AAV6 pseudotype vector transduction was unaffected by prior administration of an AAV2 or AAV3 vector, and transduction by an AAV2 pseudotype vector was unaffected by prior AAV6 vector administration, showing that cross-reactive neutralizing antibodies against AAV2 and AAV6 are not generated in mice. Interestingly, while prior administration of an AAV2 vector completely blocked transduction by a second AAV2 pseudotype vector, prior administration of an AAV6 vector only partially inhibited transduction by a second administration of an AAV6 pseudotype vector. Analysis of sera obtained from mice and humans showed that AAV6 is less immunogenic than AAV2, which helps explain this finding. These results support the development of AAV6 vectors for lung gene therapy both alone and in combination with AAV2 vectors.

5alpha-reductase type 2 mutations are present in some boys with isolated hypospadias

PURPOSE

We determined whether 5a-reductase type 2 mutations are present in boys with isolated hypospadias.

MATERIALS AND METHODS

Penile skin tissues obtained at surgery during hypospadias repair were examined for 5alpha-reductase type 2 mutations by single strand conformational polymorphism and deoxyribonucleic acid sequence analysis. Clinical data, including family history of hypospadias and preoperative position of the urethral meatus, were correlated with the genetic findings.

RESULTS

Of the 81 specimens examined 7 (8.6%) involved a mutation in at least 1, 5alpha-reductase type 2 gene, while 2 patients had mutations in both alleles. The mutations identified were A49T, L113V and H231R. The A49T mutation in 5 patients was the most common (71%) and it was generally present in less severe forms of hypospadias. To our knowledge neither the A49T nor the L113V mutation has been previously reported in association with 5alpha-reductase type 2 deficiency and to date they have only been identified in cases of isolated hypospadias. Family history was negative in the 7 patients with 5a-reductase type 2 mutations but positive in 5 without mutations.

CONCLUSIONS

Some boys with isolated hypospadias have a mutation in at least 1 gene for 5alpha-reductase type 2. This finding suggests that a partial deficiency of 5alpha-reductase activity and inadequate levels of dihydrotestosterone in the fetal urethra may be sufficient to cause the phenotype of hypospadias without other clinical features of 5alpha-reductase deficiency. Family history may not be reliable for determining which boys with hypospadias are likely to have such mutations.

High-fidelity correction of mutations at multiple chromosomal positions by adeno-associated virus vectors

The gene targeting techniques used to modify chromosomes in mouse embryonic stem cells have had limited success with many other cell types, especially normal primary cells with restricted growth capacity outside the organism. This is due in large part to the technical problems and/or inefficiency of conventional DNA transfer methods, as well as the low rates of homologous recombination obtained in unselected cell populations. We recently described an alternative approach in which adeno-associated virus (AAV) vectors were used to modify homologous chromosomal sequences, and targeting rates close to 1% were observed at the single copy hypoxanthine phosphoribosyl transferase (HPRT) locus in normal human cells (D. W. Russell and R. K. Hirata, Nat. Genet. 18:325-330, 1998). Here we report experiments in which we used a retroviral shuttle vector system to introduce and characterize target loci in human chromosomes, and demonstrate that AAV vectors can correct several types of mutations with high fidelity, independent of chromosomal position. The gene targeting rates varied depending on the type of mutation being corrected, implicating cellular mismatch recognition functions in the reaction. Since AAV vectors can efficiently deliver DNA to many cell types both in vivo and ex vivo, our results suggest that AAV-mediated gene targeting will have wide applicability, including therapeutic gene correction.

5alpha-reductase type 2 mutations are present in some boys with isolated hypospadias

PURPOSE

We determined whether 5a-reductase type 2 mutations are present in boys with isolated hypospadias.

MATERIALS AND METHODS

Penile skin tissues obtained at surgery during hypospadias repair were examined for 5alpha-reductase type 2 mutations by single strand conformational polymorphism and deoxyribonucleic acid sequence analysis. Clinical data, including family history of hypospadias and preoperative position of the urethral meatus, were correlated with the genetic findings.

RESULTS

Of the 81 specimens examined 7 (8.6%) involved a mutation in at least 1, 5alpha-reductase type 2 gene, while 2 patients had mutations in both alleles. The mutations identified were A49T, L113V and H231R. The A49T mutation in 5 patients was the most common (71%) and it was generally present in less severe forms of hypospadias. To our knowledge neither the A49T nor the L113V mutation has been previously reported in association with 5alpha-reductase type 2 deficiency and to date they have only been identified in cases of isolated hypospadias. Family history was negative in the 7 patients with 5a-reductase type 2 mutations but positive in 5 without mutations.

CONCLUSIONS

Some boys with isolated hypospadias have a mutation in at least 1 gene for 5alpha-reductase type 2. This finding suggests that a partial deficiency of 5alpha-reductase activity and inadequate levels of dihydrotestosterone in the fetal urethra may be sufficient to cause the phenotype of hypospadias without other clinical features of 5alpha-reductase deficiency. Family history may not be reliable for determining which boys with hypospadias are likely to have such mutations.

Male and female isoenzymes of steroid 5alpha-reductase

There are two steroid 5alpha-reductase isoenzymes, designated type 1 and type 2, in mammals and recent experiments show that each plays a unique physiological role. In this article, the hypothesis is developed that the type 1 gene specifies a female isoenzyme, whereas the type 2 gene specifies a male isoenzyme. This idea results from the following observations. First, mutation of the 5alpha-reductase type 1 gene in mice affects reproduction in females by decreasing fecundity and blocking parturition, but has no effect on reproduction in males. Second, mutation of the 5alpha-reductase type 2 gene in mice and men prevents proper virilization but does not affect development or reproductive function in females. Analyses of these diverse phenotypes indicate that the isoenzymes catalyse both anabolic and catabolic reactions in steroid hormone metabolism.

Bystander Trauma Care training in Iowa

OBJECTIVE

The Iowa Bystander Trauma Care program trained citizens to provide initial care at the scene of a motor vehicle crash. The development, implementation, and evaluation of the program are described.

METHODS

The National Highway Traffic Safety Administration's curriculum was used as the basis for developing the Iowa Bystander Trauma Care program. Emergency medical technicians (EMTs) were trained to be instructors in a two-hour course offered at each of four community colleges. The EMTs, in turn, provided instructions to the general populace. Five hundred participants were given a questionnaire before the one-hour Bystander Trauma Care training session, immediately after the training and six months later. The questionnaire obtained background data and assessed attitudes regarding willingness to stop and assist, and knowledge obtained.

RESULTS

One hundred twenty EMT instructors trained more than 2,000 citizen bystanders in a 17-county area in central Iowa. Immediately after the training program, participants were more likely to provide assistance (p < 0.001), and understand the sequence of actions to be performed at the scene of a crash and how to prioritize the information provided to 911 (p < 0.05). There was also evidence of retention of the knowledge six months after training.

CONCLUSIONS

Citizens readily volunteered for the Bystander Trauma Care training program. Results of the questionnaire suggest citizens can be successfully trained to recognize the needs of, and provide initial care for, acutely injured persons, and the positive effects of such training are maintained over time.

cDNA cloning of cholesterol 24-hydroxylase, a mediator of cholesterol homeostasis in the brain

The turnover of cholesterol in the brain is thought to occur via conversion of excess cholesterol into 24S-hydroxycholesterol, an oxysterol that is readily secreted from the central nervous system into the plasma. To gain molecular insight into this pathway of cholesterol metabolism, we used expression cloning to isolate cDNAs that encode murine and human cholesterol 24-hydroxylases. DNA sequence analysis indicates that both proteins are localized to the endoplasmic reticulum, share 95% identity, and represent a new cytochrome P450 subfamily (CYP46). When transfected into cultured cells, the cDNAs produce an enzymatic activity that converts cholesterol into 24S-hydroxycholesterol, and to a lesser extent, 25-hydroxycholesterol. The cholesterol 24-hydroxylase gene contains 15 exons and is located on human chromosome 14q32.1. Cholesterol 24-hydroxylase is expressed predominantly in the brain as judged by RNA and protein blotting. In situ mRNA hybridization and immunohistochemistry localize the expression of this P450 to neurons in multiple subregions of the brain. The concentrations of 24S-hydroxycholesterol in serum are low in newborn mice, reach a peak between postnatal days 12 and 15, and thereafter decline to baseline levels. In contrast, cholesterol 24-hydroxylase protein is first detected in the brain of mice at birth and continues to accumulate with age. We conclude that the cloned cDNAs encode cholesterol 24-hydroxylases that synthesize oxysterols in neurons of the brain and that secretion of 24S-hydroxycholesterol from this tissue in the mouse is developmentally regulated.

The parturition defect in steroid 5alpha-reductase type 1 knockout mice is due to impaired cervical ripening

Successful delivery of the fetus (parturition) depends on coordinate interactions between the uterus and cervix. A majority (70%) of mice deficient in the type 1 isozyme of steroid 5alpha-reductase fail to deliver their young at term and thus manifest a parturition defect. Using in vitro and in vivo measurements we show here that rhythmic contractions of the uterus occur normally in these mutant mice at the end of gestation. In contrast, the cervix of the mutant animal fails to ripen at term as judged by biomechanical, histological, and endocrinological assays. Impaired metabolism of progesterone in the cervix of the mutant mice in late gestation leads to an accumulation of this steroid in the tissue. We conclude that a failure of cervical ripening underlies the parturition defect in mice lacking steroid 5alpha-reductase type 1 and that this enzyme normally plays an essential role in cervical progesterone catabolism at the end of pregnancy.

Behavior problems of children with Down syndrome and life events

Behavior problems of 44 children with Down syndrome between the ages of 6 and 15 and 44 controls without mental retardation matched for age, sex, and socioeconomic status were compared on the basis of mother and teacher ratings. Ratings from both sources indicated that children with Down syndrome had more behavior problems, in particular attention deficit, noncompliance, thought disorder, and social withdrawal. Life events from the past year were significantly associated with mother but not teacher ratings of Down syndrome behavior problems.

The effect of peers' alcohol consumption on parental influence: a cognitive mediational model

OBJECTIVE

The current study was designed to elucidate familial and social influences on adolescent alcohol consumption by testing three hypotheses derived from the prototype/willingness model of adolescent risk behavior: (1) parents' prototypes of adolescent drinkers affect adolescent consumption through their impact on adolescents' prototypes, (2) strong parent-child relationships are associated with acceptance of parental influence regarding drinking and thus with less adolescent drinking and (3) association with peers who drink dilutes parental influence over adolescents' alcohol consumption.

METHOD

Two hundred sixty-six rural adolescents, ages 15 through 17 at Time 1, and their parents and siblings completed questionnaires about drinking behavior and drinking-related cognitions at 1-year intervals for 3 years.

RESULTS

Structural equation models provided evidence of transmission of prototypes of adolescent drinkers from parents to adolescents and evidence that these prototypes mediate adolescent alcohol consumption. They also provide evidence that although parents' prototypes and parent-adolescent relationships are important in shaping the adolescents' drinking, association with peers who drink significantly attenuates this influence.

CONCLUSIONS

These data suggest that parents can influence their children's drinking, but that this influence has more of an impact if the adolescent is not involved in a drinking-conducive peer environment. The current analyses also suggest that the process of becoming an adolescent drinker involves an active rejection of parents' influence rather than a passive movement away from parents' attitudes and beliefs-a process that is accelerated by association with peers who drink.

17Beta-hydroxysteroid dehydrogenase 3 deficiency in women

In genetic males, mutation of the 17beta-hydroxysteroid dehydrogenase 3 (17HSD3)gene that is normally expressed in the testes impairs testosterone formation and causes development of male pseudohermaphroditism. We have ascertained seven women who are sisters of men with 17HSD3 deficiency and who are either homozygotes or compound heterozygotes for the same mutations as their affected brothers. Our findings confirm the concept that women with such mutations are asymptomatic.

cDNA cloning of mouse and human cholesterol 25-hydroxylases, polytopic membrane proteins that synthesize a potent oxysterol regulator of lipid metabolism

Oxysterols regulate the expression of genes involved in cholesterol and lipid metabolism and serve as intermediates in cholesterol catabolism. Among the most potent of regulatory oxysterols is 25-hydroxycholesterol, whose biosynthetic enzyme has not yet been isolated. Here, we report the cloning of cholesterol 25-hydroxylase cDNAs from the mouse and human. The encoded enzymes are polytopic membrane proteins of 298 and 272 amino acids, respectively, which contain clusters of histidine residues that are essential for catalytic activity. Unlike most other sterol hydroxylases, cholesterol 25-hydroxylase is not a cytochrome P450, but rather it is a member of a small family of enzymes that utilize diiron cofactors to catalyze the hydroxylation of hydrophobic substrates. The cholesterol 25-hydroxylase gene lacks introns, and in the human it is located on chromosome 10q23. The murine gene is expressed at low levels in multiple tissues. Expression of cholesterol 25-hydroxylase in transfected cells reduces the biosynthesis of cholesterol from acetate and suppresses the cleavage of sterol regulatory element binding protein-1 and -2. The data suggest that cholesterol 25-hydroxylase has the capacity to play an important role in regulating lipid metabolism by synthesizing a co-repressor that blocks sterol regulatory element binding protein processing and ultimately leads to inhibition of gene transcription.

Helper-free foamy virus vectors

Retroviral vectors based on human foamy virus (HFV) have been developed and show promise as gene therapy vehicles. Here we describe a method for the production of HFV vector stocks free of detectable helper virus. The helper and vector plasmid constructs used both lack the HFV bel genes, so recombination between these constructs cannot create a wild-type virus. A fusion promoter that combines portions of the cytomegalovirus (CMV) immediate-early and HFV long terminal repeat (LTR) promoters was used to drive expression of both the helper and vector constructs. The CMV-LTR fusion promoter allows for HFV vector production in the absence of the Bel-1 trans-activator protein, which would otherwise be necessary for efficient transcription from the HFV LTR. Vector stocks containing either neomycin phosphotransferase or alkaline phosphatase reporter genes were produced by transient transfection at titers greater than 10(5) transducing units/ml. G418-resistant BHK-21 cells obtained by transduction with neo vectors contained randomly integrated HFV vector proviruses without detectable deletions or rearrangements. The vector stocks generated were free of replication-competent retrovirus (RCR), as determined by assays for LTR trans-activation and a marker rescue assay developed here for the detection of Bel-independent RCR.

The hypoxia-responsive transcription factor EPAS1 is essential for catecholamine homeostasis and protection against heart failure during embryonic development

Mice lacking the hypoxia-inducible transcription factor EPAS1 die at mid-gestation. Despite normal morphological development of the circulatory system, EPAS1-deficient mice display pronounced bradycardia. In addition to the vascular endothelium, EPAS1 is expressed intensively in the organ of Zuckerkandl (OZ), the principle source of catecholamine production in mammalian embryos. EPAS1-deficient embryos contained substantially reduced catecholamine levels. Mid-gestational lethality was rescued by administration of the catecholamine precursor DOPS to pregnant females. We hypothesize that EPAS1 expressed in the OZ senses hypoxia during mid-gestational development and translates this signal into an altered pattern of gene expression, leading to increases in circulating catecholamine levels and proper cardiac function.

Identification of a new inborn error in bile acid synthesis: mutation of the oxysterol 7alpha-hydroxylase gene causes severe neonatal liver disease

We describe a metabolic defect in bile acid synthesis involving a deficiency in 7alpha-hydroxylation due to a mutation in the gene for the microsomal oxysterol 7alpha-hydroxylase enzyme, active in the acidic pathway for bile acid synthesis. The defect, identified in a 10-wk-old boy presenting with severe cholestasis, cirrhosis, and liver synthetic failure, was established by fast atom bombardment ionization-mass spectrometry, which revealed elevated urinary bile acid excretion, a mass spectrum with intense ions at m/z 453 and m/z 510 corresponding to sulfate and glycosulfate conjugates of unsaturated monohydroxy-cholenoic acids, and an absence of primary bile acids. Gas chromatography-mass spectrometric analysis confirmed the major products of hepatic synthesis to be 3beta-hydroxy-5-cholenoic and 3beta-hydroxy-5-cholestenoic acids, which accounted for 96% of the total serum bile acids. Levels of 27-hydroxycholesterol were > 4,500 times normal. The biochemical findings were consistent with a deficiency in 7alpha-hydroxylation, leading to the accumulation of hepatotoxic unsaturated monohydroxy bile acids. Hepatic microsomal oxysterol 7alpha-hydroxylase activity was undetectable in the patient. Gene analysis revealed a cytosine to thymidine transition mutation in exon 5 that converts an arginine codon at position 388 to a stop codon. The truncated protein was inactive when expressed in 293 cells. These findings indicate the quantitative importance of the acidic pathway in early life in humans and define a further inborn error in bile acid synthesis as a metabolic cause of severe cholestatic liver disease.

Packaging cells based on inducible gene amplification for the production of adeno-associated virus vectors

Although vectors based on adeno-associated virus (AAV) offer several unique advantages, their usage has been hampered by the difficulties encountered in vector production. In this report, we describe a new AAV packaging system based on inducible amplification of integrated helper and vector constructs containing the simian virus 40 (SV40) replication origin. The packaging and producer cell lines developed express SV40 T antigen under the control of the reverse tetracycline transactivator system, which allows inducible amplification of chromosomal loci linked to the SV40 origin. Culturing these cells in the presence of doxycycline followed by adenovirus infection resulted in helper and vector gene amplification as well as higher vector titers. Clonal producer cell lines generated vector titers that were 10 times higher than those obtained by standard methods, with approximately 10(4) vector particles produced per cell. These stocks were free of detectable replication-competent virus. The lack of a transfection step combined with the reproducibility of stable producer lines makes this packaging method ideally suited for the large-scale production of vector stocks for human gene therapy.