Immunologic response to vaccine challenge in pregnant PTPN22 R620W carriers and non-carriers.

OBJECTIVES: Influenza infection is a significant cause of respiratory morbidity among pregnant women. Seasonal influenza vaccination engages innate immune receptors to promote protective immunity. A coding polymorphism (R620W) in PTPN22 imparts elevated risk for human infection and autoimmune disease, predisposes to diminished innate immune responses, and associates with reduced immunization responses. We sought to quantify the effects of PTPN22-R620W on humoral and cell-mediated immune responses to the inactivated influenza vaccine among healthy pregnant women. STUDY DESIGN: Immune responses were measured in healthy pregnant R620W carrier (n = 17) and non-carrier (n = 33) women receiving the 2013 quadrivalent inactivated influenza vaccine (Fluzone). Hemagglutination inhibition assays were performed to quantify neutralizing antibodies; functional influenza-reactive CD4 T cells were quantified by flow cytometry, and influenza-specific CD8 T cells were enumerated with MHC Class I tetramers. Antibody seroconversion data were evaluated by Chi-square analysis, and the Mann-Whitney or Wilcoxon signed-rank tests were applied to T cell response data. RESULTS: PTPN22 R620W carrier (n = 17) and non-carrier (n = 33) groups did not differ in age, parity, BMI, gestational age at time of vaccine, or history of prior influenza vaccination. After Fluzone exposure, 51.5% of non-carriers met criteria for antibody seroconversion to H1N1 influenza, compared with 23.5% of R620W carriers (p = 0.06). Influenza-reactive CD4 T cells showed modest increase at days 9-15 after vaccination in both R620W carriers and non-carriers (p = 0.02 and p = 0.04, respectively). However, there was no difference in overall response between the two groups (p = 0.6). The vaccine did not result in significant induction of influenza-specific CD8 T cells in either group. CONCLUSIONS: There was no significant difference among healthy pregnant R620W carriers and non-carriers in H1N1 antibody seroconversion rates after influenza vaccination. Studies of larger cohorts will be needed to define the effect of PTPN22 risk allele carriage on antibody and T cell responses to influenza vaccination during pregnancy.

Body Composition Trajectories From Infancy to Preschool in Children Born Premature Versus Full-term.

OBJECTIVES: The aim of the study was to longitudinally characterize infancy to preschool body composition trajectories and the association of early fat and fat-free mass gains with preschool age body composition in children born premature versus full-term. METHODS: A cohort of appropriate-for-gestational age preterm (n = 20) and term (n = 51) infants were followed at 3 visits: "neonatal" visit 1 at 2 weeks of age for term and near term corrected age for preterm; "infancy" visit 2 at 3 to 4 months (preterm corrected age); "preschool" visit 3 at 4 years. Body composition via air displacement plethysmography and anthropometrics were measured at all visits. Tracking of infancy weight and body composition with preschool measurements was tested using Pearson partial correlation coefficients. Associations between serial body composition measurements were assessed using multiple linear regression. RESULTS: Early differences in body composition between premature (mean gestational age 31.9 weeks, mean birth weight 1843 g) and full-term (mean gestational age 39.8 weeks) infants were not present at preschool age. Visit 1 body composition was not correlated with preschool measurements in the preterm infants. Visit 2 measurements were correlated with preschool measures. Fat-free mass accretion from visit 1 to visit 2 was positively associated with preschool lean mass (ß = 0.038, P = 0.049) in preterm children, whereas fat accretion was not associated with preschool body composition. CONCLUSIONS: Children born prematurely and full-term have similar body composition at preschool age. For preterms infancy fat-free mass gains, and not adiposity gains, are positively associated with preschool fat-free mass; this may be associated with lower risk of later obesity and adverse metabolic outcomes.

Greater Early Gains in Fat-Free Mass, but Not Fat Mass, Are Associated with Improved Neurodevelopment at 1 Year Corrected Age for Prematurity in Very Low Birth Weight Preterm Infants.

OBJECTIVE: This work investigates the relationship between early body composition changes and neurodevelopment at 1 year age corrected for prematurity (CA). STUDY DESIGN: A prospective, longitudinal study to measure body composition weekly in 34 very low birth weight preterm infants using air displacement plethysmography, beginning when infants stabilized after birth until discharge. Neurodevelopmental testing (Bayley Scales of Infant Development-III) was performed at 12 months CA. Linear mixed effects models were used to obtain inpatient subject-specific changes in fat-free mass (FFM) and fat mass (FM), which were then used as predictors of Bayley subscale scores in subsequent linear regression models, adjusting for potential confounders. Protein and energy provision were calculated for the first week of life. RESULTS: Greater FFM gains while inpatient were associated with improved cognitive and motor scores at 12 months CA (P = .002 for both). These relationships remained significant when adjusting for birth weight, gestational age, and intraventricular hemorrhage (P ≤ .05 for both). Similar analysis was performed for FM gains without significant findings. Increased provision of protein and calories during the first week of life was positively associated with FFM gains (P ≤ .01 for both), but not FM gains (P ≥ .2 for both), throughout hospitalization. CONCLUSIONS: Increased FFM gains, but not FM gains, during hospitalization are associated with improved neurodevelopment at 12 months CA. As early FM gains may be associated with long-term risk, more research is needed to develop strategies that optimize FFM gains while minimizing FM gains in very low birth weight preterm infants.

Exploratory study of the relationship of fat-free mass to speed of brain processing in preterm infants.

BACKGROUND: Preterm infants are at risk for long-term neurodevelopmental impairment as a function of postnatal nutritional status. Despite adequate neonatal weight gain, preterm infants have altered body composition, with lower fat-free mass (FFM) and higher adiposity at term corrected gestational age (CGA) than their term counterparts. The relationship between postnatal body composition and speed of brain processing in preterm infants is unknown. METHODS: Anthropometric measurements and body composition testing via air displacement plethysmography were performed on 16 appropriate-for-gestational age (GA) preterm (mean GA: 30.4 ± 2.8 wk) infants at term and 4 mo CGA. Infant visual pathway development was assessed at 4 mo CGA using pattern-reversal visual evoked potential (VEP); P100 (positive peak) latency was used to index neuronal speed of processing. RESULTS: Increased FFM at discharge (P = 0.02) and 4 mo CGA (P = 0.006) was associated with shorter latencies to the P100 peak. P100 latency was not related to total body weight, fat mass, or body fat percentage. CONCLUSION: FFM reflects protein accretion and indexes growth of organs, including the brain. The association of shorter VEP latency (i.e., faster neuronal processing) with higher FFM (i.e., better protein status) may be attributed to the positive effects of protein status on neuronal growth and differentiation.

Decelerated early growth in infants of overweight and obese mothers.

OBJECTIVE: To investigate the relationship between maternal prepregnancy body mass index and early infant growth and body composition. STUDY DESIGN: Prospective cohort study performed at a university hospital/surrounding community. Ninety-seven nondiabetic mothers with singleton, term, healthy infants completed study visits at 2 weeks and 3 months of age. Before pregnancy, 59 mothers were normal weight, 18 were overweight, and 20 were obese. Infant anthropometrics and body composition via air-displacement plethysmography were measured. Infant feeding information and maternal prepregnancy weight were self-reported. Additional data were obtained via self-report and the medical record. Main outcome measures were change in weight, length, fat-free mass, and fat mass from 2 weeks to 3 months of age. Analysis was done via multivariate linear regression. RESULTS: At 2 weeks, anthropometrics and body composition did not differ across maternal body mass index groups. At 3 months, infants of overweight or obese mothers had gained less weight (P = .02), grew less in length (P = .01), and gained less fat mass (P = .01). Adjustment for breastfeeding status and regression to the mean via conditional change variables did not alter the results. The results were not altered after adjusting for maternal glucose values from a 50-g glucose challenge and for maternal smoking in a subset including 80% of the women. CONCLUSIONS: Maternal overweight/obesity is associated with early deceleration in linear growth and adipose tissue accrual; replication of these findings is needed.

The relationship of poor linear growth velocity with neonatal illness and two-year neurodevelopment in preterm infants.

BACKGROUND: Poor postnatal weight gain in very low birth weight (VLBW) preterm infants has been shown to have a negative effect on neurodevelopment. However, the dose-dependent neurodevelopmental consequences of linear stunting in this population have not previously been assessed. Understanding this relationship is important because organ growth and differentiation are more tightly linked to lean body mass and thus linear growth. OBJECTIVE: To assess the duration and clinical determinants of poor linear growth and its relationship to neurodevelopment in preterm infants. METHODS: Weight, recumbent length and head circumference were recorded at birth, hospital discharge, and at 4, 12 and 24 months corrected age (CA) in 62 VLBW infants. Standardized Z-scores for weight (WZ), length (LZ) and head circumference (HCZ) were calculated and assessed as a function of inpatient clinical factors using linear regression models. Twenty-four-month neurodevelopmental function was analyzed as a function of growth status. RESULTS: Mean LZ was lower than WZ (p = 0.004) at hospital discharge, was related in part to illness severity and remained lower than baseline LZ until 24 months CA. Controlling for WZ and HCZ at each age, lower LZ at 4 and 12 months CA was associated with lower cognitive function scores at 24 months CA (p ≤ 0.03). CONCLUSIONS: Nutritional and non-nutritional factors influenced the degree of pre- and postdischarge linear growth suppression in VLBW infants, which in turn was negatively associated with developmental outcomes at 24 months CA. Since linear growth correlates with brain growth and indexes a number of clinical factors, it is an important biomarker that can be used in VLBW infants to predict long-term developmental outcomes.

Body composition changes in preterm infants following hospital discharge: comparison with term infants.

BACKGROUND AND OBJECTIVES: Infants experiencing catch-up growth devote a greater proportion of their energy to fat deposition, potentially at the expense of gains in lean body mass. The objective of the present study was to compare the body composition of preterm and term infants after hospital discharge and to determine the effect of gestational age (GA), birth size, nutrition, and illness on growth in fat-free mass (FFM) after hospitalization. PATIENTS AND METHODS: Anthropometric measurements and body composition testing via air displacement plethysmography were performed on 26 appropriate-for-gestational-age (AGA) preterm (mean GA 31.5  ±â€Š 2.7 weeks) and 97 AGA term (mean GA 39.8 ± 1.0 weeks) infants at term corrected age (CA) and at 3 to 4 months CA. RESULTS: At term CA, preterm infants had lower FFM (3.0 vs 3.3 kg, P = 0.001), higher percentage of body fat (18.7% vs 15.2%, P < 0.0001), lower weight (P =0.04), and shorter length (P = 0.001) than term infants. By 3 to 4 months CA, weight, length, percentage of body fat, and FFM were similar in the 2 groups. GA, inpatient nutrition, and illness were associated with FFM at 4 months CA in the preterm infants (P < 0.05). CONCLUSIONS: Markedly lower FFM and higher adiposity were observed in preterm infants at term CA, but these differences had lessened and were no longer statistically significant at 3 to 4 months CA. Although early nutrition was associated with growth trajectories in the hospital, the continuing influence of early illness on postdischarge growth suggests that nonnutritional factors (eg, disturbances in the growth hormone axis) also may affect body composition trajectories of preterm infants.

Increasing the ranks of academic researchers in mental health: a multisite approach to postdoctoral fellowship training.

This report highlights the use of multisite training for psychiatry and psychology postdoctoral fellows developing careers in academic clinical research in the field of mental health. The objective is to describe a model of training for young investigators to establish independent academic clinical research careers, including (1) program structure and eligibility, (2) program goals and development of a multisite curriculum, (3) use of technology for implementing the program across multiple sites, and (4) advantages and challenges of this multisite approach. In 2000, in collaboration with the Veterans Affairs (VA) Mental Illness Research, Education and Clinical Centers (MIRECCs), the VA Office of Academic Affiliations launched the Special Fellowship Program in Advanced Psychiatry and Psychology. Each of the 10 currently participating VA sites across the United States is affiliated with a MIRECC and an academic medical institution. In the first five years of this fellowship program, 83 fellows (34 psychiatrists and 49 psychologists) have participated. The success of this multisite approach is evidenced by the 58 fellows who have already graduated from the program: 70% have entered academic clinical research positions, and over 25 have obtained independent extramural grant support from the VA or the National Institutes of Health. Multisite training results in a greater transfer of knowledge and capitalizes on the nationwide availability of experts, creating unique networking and learning opportunities for trainees. The VA's multisite fellowship program plays a valuable role in preparing substantial numbers of psychiatry and psychology trainees for a range of academic clinical research and leadership positions in the field of mental health.

Using the Revised Acculturation Rating Scale for Mexican Americans (ARSMA-II) with Older Adults.

Projections for the year 2030 show that Latinos are expected to make the largest population increase. Cultural values create expectation levels about what will happen to the elderly. Acculturation is a concept that has been studied extensively, yet the relationship between age and acculturation has not been a focus of study. The present study has proposed an alternate way of scoring the ARSMA-II based on receiver operating characteristics. Specifically, this approach looks at participants' responses to two individual items to determine the level of acculturation of the older adults. It is a quicker method and one that could save healthcare providers a great deal of time as well as help them better understand their clients' level of acculturation; thus, being able to provide the appropriate educational materials.

Ethnic differences in beliefs regarding Alzheimer disease among dementia family caregivers.

OBJECTIVE: The purpose of this study was to examine ethnic differences in female dementia family caregivers' knowledge, attitudes, and beliefs about Alzheimer disease (AD). METHODS: Baseline data were collected from 215 female caregivers before their participation in various psychoeducational intervention programs. Caregivers were questioned about the epidemiology, etiology, and treatment of AD. Logistic regressions and one-way analysis of variance were conducted to assess ethnic differences. RESULTS: Hispanic and Chinese caregivers were more likely to believe that AD is a normal part of aging and that AD can be diagnosed by a blood test than the white group. These beliefs about AD may delay help-seeking activities for these patients and their family caregivers. CONCLUSION: Increased public education about AD is needed in these communities. Results are discussed in terms of barriers to accessing information about AD and ways to improve public informational outreach activities, so that the intended audiences are reached more effectively.

The relationship between objectively measured sleep disturbance and dementia family caregiver distress and burden.

The aim of this study was to determine whether distress and burden were associated with objective measures of sleep disturbance in dementia caregivers. Using wrist actigraphy, sleep was measured in 60 female, Caucasian dementia family caregivers (mean age, 64.8 years). Caregivers completed questionnaires about demographics, health, depression, duration of caregiving and care recipient nighttime behavior. Care recipients completed a mental status exam. We investigated whether these measures were associated with actigraphic sleep parameters. Greater depressive symptoms among caregivers were associated with poorer sleep efficiency. Older caregiver age and poorer self-rated health were associated with longer time in bed. Sleep disturbance, which is common among dementia caregivers, might be an important index of caregiver distress (ie, depression) but might not be associated with burden (based on the care recipient's general cognitive impairment or nighttime awakenings.).

Effectiveness of Cognitive/Behavioral Small Group Intervention for Reduction of Depression and Stress in Non-Hispanic White and Hispanic/Latino Women Dementia Family Caregivers: Outcomes and Mediators of Change.

This study enrolled 184 middle-aged and older women (95 Non-Hispanic White and 89 Hispanic/Latino) who provided in-home hands-on care to an elderly relative with Alzheimer's disease or another form of dementia. Within ethnic group they were randomly assigned to either a CBT-based small group intervention program called "Coping with Caregiving" (CWC) that taught a variety of cognitive and behavioral skills to reduce stress and depression, or to a minimal telephone based control condition (TSC). Intervention lasted about 4 months; one post-treatment assessment was completed 6 months after baseline by interviewers blind to the intervention condition. Interviews and interventions were conducted in English or Spanish by trained staff. Results indicated that those in the CWC (regardless of ethnicity) showed greater improvement from pre to post intervention than those in the TSC on measures of depressive symptoms, overall life stress, and caregiving-specific stress. In order to investigate if these changes may have been related to one proposed mechanism of change in CBT (skill utilization), a new measure was constructed. Change in frequency of use and perceived helpfulness of adaptive coping skills were assessed in all caregivers. Results indicated that caregivers in CWC reported greater frequency of use, and greater perceived helpfulness, of these skills at post intervention compared to caregivers in the TSC. Improvement measured by dependent measures was correlated with an increase in these indices for those in the CWC. Tests for mediation suggest that effective skill utilization may mediate the effect of treatment on outcome. Implications of these findings are discussed and recommendations provided for future research.

Impact of in-home behavioral management versus telephone support to reduce depressive symptoms and perceived stress in Chinese caregivers: results of a pilot study.

OBJECTIVE: Recent work has shown that Chinese Americans caring for a family member with dementia experience considerable psychological distress. However, few studies evaluate treatments for them. This study evaluated the efficacy of in-home intervention, based on cognitive behavior therapy principles, to relieve stress and depression in female Chinese American caregivers (CGs). METHODS: Fifty-five CGs who met inclusion criteria were randomly assigned to a telephone support condition (TSC) or to an in-home behavioral management program (IHBMP) for 4 months. In the TSC, biweekly calls were made and relevant material was mailed. In the IHBMP, specific psychological skills were taught to deal with caregiving stress. CGs were assessed before and after treatment. Outcome measures evaluated overall perceived stress, caregiving-specific stress, and depressive symptoms. RESULTS: CGs in IHBMP were less bothered by caregiving-specific stressors and had lower depression levels than CGs in TSC. There was no difference in overall stress. CGs with low baseline level of self-efficacy for obtaining respite benefited from IHBMP, but showed little improvement in the TSC. CGs with higher self-efficacy benefited from both treatments. CONCLUSION: This intervention is promising and warrants replication in future studies. Additional research is needed to evaluate longer-term effects and to identify individual differences associated with improvement.

The analysis of mitochondria and mitochondrial DNA in human embryonic stem cells.

As human embryonic stem cells (hESCs) undergo differentiation, they express genes characteristic of the lineage for which they are destined. However, fully differentiated individual cell types can be characterized by the number of mitochondria they possess and the copies of the mitochondrial genome per mitochondrion. These characteristics are indicative of a specific cell's requirement for adenosine triphosphate (ATP) and therefore cellular viability and function. Consequently, failure for an ESC to possess the full complement of mitochondria and mitochondrial DNA (mtDNA) could limit its final commitment to a particular fate. We describe a series of protocols that analyze the process of cellular mitochondrial and mtDNA differentiation during hESC differentiation. In addition, mtDNA transcription and replication are key events in cellular differentiation that require interaction between the nucleus and the mitochondrion. To this extent, we describe a series of protocols that analyze the initiation of these key events as hESCs progress from their undifferentiated state to the fully committed cell. Last, we describe real-time polymerase chain reaction protocols that allow both the identification of mtDNA copy number and determine whether mtDNA copy is uniform (homoplasmy) in its transmission or heterogeneous (heteroplasmy).

Ethnicity, stress, and cortisol function in Hispanic and non-Hispanic white women: A preliminary study of family dementia caregivers and noncaregivers.

OBJECTIVE: This study examined differences in psychologic and physiological responses to caregiving stress in Hispanic and non-Hispanic white women dementia caregivers and noncaregivers. Dependent variables were perceived stress, depression, and salivary cortisol. METHOD: Eighty-three women caregivers (20 Hispanic and 24 non-Hispanic white) and noncaregivers (19 Hispanic and 20 non-Hispanic white) completed the Perceived Stress Scale (PSS), Center for Epidemiological Studies-Depression Scale (CES-D), and collected three saliva samples daily for 3 consecutive days. A subsample of 17 Hispanic and 28 non-Hispanic white participants matched on age and education was used for the main analyses. RESULTS: Caregivers had higher levels of 8 am, 5 pm, and 9 pm log cortisol as well as higher perceived stress than noncaregivers. Non-Hispanic whites had higher depression scores than noncaregivers, but there was no significant difference for Hispanics. Hispanics, regardless of caregiving status had flatter daytime cortisol slopes than the non-Hispanic whites. Multivariate regression analyses showed that both ethnicity and depressive symptoms independently predicted daytime cortisol slope. CONCLUSIONS: Results support the relationship between chronic stress and hypothalamic-pituitary-adrenal axis dysregulation among women dementia caregivers and highlight the need to examine further the role of ethnicity and depressive symptoms in their physiological responses.

Lamin A/C expression is a marker of mouse and human embryonic stem cell differentiation.

Nuclear lamins comprise the nuclear lamina, a scaffold-like structure that lines the inner nuclear membrane. B-type lamins are present in almost all cell types, but A-type lamins are expressed predominantly in differentiated cells, suggesting a role in maintenance of the differentiated state. Previous studies have shown that lamin A/C is not expressed during mouse development before day 9, nor in undifferentiated mouse embryonic carcinoma cells. To further investigate the role of lamins in cell phenotype maintenance and differentiation, we examined lamin expression in undifferentiated mouse and human embryonic stem (ES) cells. Wide-field and confocal immunofluorescence microscopy and semiquantitative reverse transcription-polymerase chain reaction analysis revealed that undifferentiated mouse and human ES cells express lamins B1 and B2 but not lamin A/C. Mouse ES cells display high levels of lamins B1 and B2 localized both at the nuclear periphery and throughout the nucleoplasm, but in human ES cells, B1 and B2 expression is dimmer and localized primarily at the nuclear periphery. Lamin A/C expression is activated during human ES cell differentiation before downregulation of the pluripotency marker Oct-3/4 but not before the downregulation of the pluripotency markers Tra-1-60, Tra-1-81, and SSEA-4. Our results identify the absence of A-type lamin expression as a novel marker for undifferentiated ES cells and further support a role for nuclear lamins in cell maintenance and differentiation.

The expression of mitochondrial DNA transcription factors during early cardiomyocyte in vitro differentiation from human embryonic stem cells.

Mitochondrial biogenesis and activation of both oxidative phosphorylation, as well as transcription and replication of the mitochondrial genome, are key regulatory events in cell differentiation. Mitochondrial DNA transcription and replication are highly dependent on the interaction with nuclear-encoded transcription factors translocated from the nucleus. Using a human embryonic stem cell line, HSF 6, we analyzed the proliferation of mitochondria and the expression of mtDNA-specific transcription factors in undifferentiated, migratory embryonic stem cells and spontaneously derived cardiomyocytes. Mitochondrial proliferation and mtDNA transcription are initiated in human embryonic stem cells as they undergo spontaneous differentiation in culture into beating cardiomyocytes. Undifferentiated, pluripotent human embryonic stem cells have few mitochondria, and, as they differentiate, they polarize to one extremity of the cell and then bipolarize the differentiating cell. The differentiated cell then adopts the cytoplasmic configuration of a somatic cell as evidenced in differentiating cardiomyocytes. Transcription and replication of the extranuclear mitochondrial genome is dependent on nuclear encoded factors exported to the mitochondrion. However, the differentiating cardiomyocytes have reduced or absent levels of these transcription and replication factors, namely mitochondrial transcription factors A, B1, B2, and nuclear respiratory factor 1 and polymerase gamma. Therefore, final embryonic stem cell commitment may be influenced by mitochondrial proliferation and mtDNA transcription. However, it is likely that differentiating cardiomyocytes are in mitochondrial arrest, awaiting commitment to a final cell fate.

Futile cycling of lactate through the plasma membrane of C6 glioma cells as detected by (13C, 2H) NMR.

We report a novel ((13)C, (2)H) nuclear magnetic resonance (NMR) procedure to investigate lactate recycling through the monocarboxylate transporter of the plasma membrane of cells in culture. C6 glioma cells were incubated with [3-(13)C]lactate in Krebs-Henseleit Buffer containing 50% (2)H(2)O (vol/vol) for up to 30 hr. (13)C NMR analysis of aliquots progressively taken from the medium, showed: (1) a linearly decreasing singlet at approximately 20.85 parts per million (ppm; -0.119 micromol/mg protein/hr) derived from the methyl carbon of [3-(13)C]lactate; and (2) an exponentially increasing shifted singlet at approximately 20.74 ppm (0.227 micromol/ mg protein/hr) from the methyl carbon of [3-(13)C, 2-(2)H]lactate. The shifted singlet appears because during its transit through the cytosol, [3-(13)C]lactate generates [3-(13)C, 2-(2)H]lactate in the lactate dehydrogenase (LDH) equilibrium, which may return to the incubation medium through the reversible monocarboxylate carrier. The methyl group of [3-(13)C, 2-(2)H]lactate is shifted -0.11 ppm with respect to that of [3-(13)C]lactate, making it possible to distinguish between both molecules by (13)C NMR. During incubations with 2.5 mM [1-(13)C]glucose and 3.98 mM [U-(13)C(3)]lactate or with 2.5 mM [1-(13)C]glucose and 3.93 mM [2-(13)C]pyruvate, C2-deuterated lactate was produced only from [1-(13)C]glucose or [U-(13)C(3)]lactate, revealing that this deuteration process is redox sensitive. When [1-(13)C]glucose and [U-(13)C(3)]lactate were used as substrates, no significant [3-(13)C]lactate production from [1-(13)C]glucose was detected, suggesting that glycolytic lactate production may be stopped under the high lactate concentrations prevailing under mild hypoxic or ischemic episodes or during cerebral activation.

Cerebral glucose metabolism and the glutamine cycle as detected by in vivo and in vitro 13C NMR spectroscopy.

We review briefly 13C NMR studies of cerebral glucose metabolism with an emphasis on the roles of glial energetics and the glutamine cycle. Mathematical modeling analysis of in vivo 13C turnover experiments from the C4 carbons of glutamate and glutamine are consistent with: (i) the glutamine cycle being the major cerebral metabolic route supporting glutamatergic neurotransmission, (ii) glial glutamine synthesis being stoichiometrically coupled to glycolytic ATP production, (iii) glutamine serving as the main precursor of neurotransmitter glutamate and (iv) glutamatergic neurotransmission being supported by lactate oxidation in the neurons in a process accounting for 60-80% of the energy derived from glucose catabolism. However, more recent experimental approaches using inhibitors of the glial tricarboxylic acid (TCA) cycle (trifluoroacetic acid, TFA) or of glutamine synthase (methionine sulfoximine, MSO) reveal that a considerable portion of the energy required to support glutamine synthesis is derived from the oxidative metabolism of glucose in the astroglia and that a significant amount of the neurotransmitter glutamate is produced from neuronal glucose or lactate rather than from glial glutamine. Moreover, a redox switch has been proposed that allows the neurons to use either glucose or lactate as substrates for oxidation, depending on the relative availability of these fuels under resting or activation conditions, respectively. Together, these results suggest that the coupling mechanisms between neuronal and glial metabolism are more complex than initially envisioned.

Variation in the HLA-G promoter region influences miscarriage rates.

The HLA-G gene is primarily expressed in placental cells that invade the maternal decidua during pregnancy. This gene encodes multiple isoforms that fulfill a variety of functions at the maternal-fetal interface throughout gestation. Recently, a null allele for the most abundant HLA-G isoform was associated with recurrent miscarriage in two independent studies, suggesting that reduced levels of the HLA-G1 protein may compromise successful pregnancy. We initiated the present study to determine whether other polymorphisms that could affect expression levels of HLA-G were associated with fetal loss in women participating in a 15-year prospective study of pregnancy outcome. We genotyped these subjects for 18 single-nucleotide polymorphisms in the 1,300 bp upstream of exon 1, 13 of which were identified as part of this study, as well as for an insertion/deletion (in/del) polymorphism in the 3' untranslated region. The 18 SNPs defined eight unique haplotypes. One polymorphism, -725C/G, was associated with fetal loss, with an increased risk for miscarriage in couples in which both partners carried the -725G allele, compared with couples not carrying this allele (odds ratio 2.76, 95% confidence interval 1.08-7.09; P=.035). Further, the G at nucleotide -725 creates a CpG dinucleotide, and we demonstrate that this CpG site is methylated on -725G alleles. Overall, this study identified extraordinary levels of variation in the 5'-upstream regulatory region of HLA-G and provides evidence for an association between a promoter-region SNP and fetal loss rates, further attesting to the novel features and critical role of this gene in pregnancy.