The First Pulmonary Hypertension Registry in the United Arab Emirates (UAEPH): Clinical Characteristics, Hemodynamic Parameters with Focus on Treatment and Outcomes for Patients with Group 1-PH.

BACKGROUND: The aim of this study is to present the first United Arab Emirates pulmonary hypertension registry of patients' clinical characteristics, hemodynamic parameters and treatment outcomes. METHOD: This is a retrospective study describing all the adult patients who underwent a right heart catheterization for evaluation of pulmonary hypertension (PH) between January 2015 and December 2021 in a tertiary referral center in Abu Dhabi, United Arab Emirates. RESULTS: A total of 164 consecutive patients were diagnosed with PH during the five years of the study. Eighty-three patients (50.6%) were World Symposium PH Group 1-PH; nineteen patients (11.6%) were Group 2-PH due to left heart disease; twenty-three patients (14.0%) were Group 3-PH due to chronic lung disease; thirty-four patients (20.7%) were Group 4-PH due to chronic thromboembolic lung disease, and five patients (3.0%) were Group 5-PH. Among Group 1-PH, twenty-five (30%) had idiopathic, twenty-seven (33%) had connective tissue disease, twenty-six (31%) had congenital heart disease, and five patients (6%) had porto-pulmonary hypertension. The median follow-up was 55.6 months. Most of the patients were started on dual then sequentially escalated to triple combination therapy. The 1-, 3- and 5-year cumulative probabilities of survival for Group 1-PH were 86% (95% CI, 75-92%), 69% (95% CI, 54-80%) and 69% (95% CI, 54-80%). CONCLUSIONS: This is the first registry of Group 1-PH from a single tertiary referral center in the UAE. Our cohort was younger with a higher percentage of patients with congenital heart disease compared to cohorts from Western countries but similar to registries from other Asian countries. Mortality is comparable to other major registries. Adopting the new guideline recommendations and improving the availability and adherence to medications are likely to play a significant role in improving outcomes in the future.

Vitamin D Supplementation Improves Health-Related Quality of Life and Physical Performance in Children with Sickle Cell Disease and in Healthy Children.

INTRODUCTION: No study determined if vitamin D supplementation improves health-related quality of life (HRQL) using pediatric Patient-Reported Outcomes Measurement Information System or physical functioning in type SS sickle cell disease (HbSS). METHOD: Subjects with HbSS (n = 21) and healthy subjects (n = 23) were randomized to daily oral doses (4,000 vs. 7,000 IU) of cholecalciferol (vitamin D3) and evaluated at 6 and 12 weeks for changes in serum 25 hydroxyvitamin D (25(OH)D), HRQL, and physical functioning. RESULTS: In subjects with HbSS, significant reductions in pain, fatigue, and depressive symptoms and improved upper-extremity function were observed. In healthy subjects, significant reductions in fatigue and improved upper-extremity function were observed. Significant improvements in peak power and dorsiflexion isometric maximal voluntary contraction torques were observed in both groups. In subjects with HbSS, improved plantar flexion isometric maximal voluntary contraction torques were observed. Both groups saw significant improvement in their total Bruininks-Oseretsky Test of Motor Proficiency score. DISCUSSION: Daily high-dose vitamin D supplementation for African American children with and without HbSS improved HRQL and physical performance.

Differential developmental refinement of the intrinsic electrophysiological properties of CA1 pyramidal neurons from the rat dorsal and ventral hippocampus.

The dorsal and ventral regions of the rat longitudinal hippocampal axis are functionally distinct. That is, each region is associated with different behavioral tasks and disease susceptibilities due to underlying anatomical, and physiological differences. These differences are especially pronounced in area CA1, where significant differences in morphology, synaptic physiology, intrinsic excitability, and gene expression have been reported between CA1 pyramidal neurons from the dorsal (DHC) and ventral hippocampus (VHC). However, despite a significant amount of recent attention, a cogent picture of the intrinsic electrophysiological profile of DHC and VHC neurons has remained elusive, due, in part, to experiments performed on rats at different developmental time points. Moreover, the resulting intrinsic electrophysiological profiles are sufficiently different as to warrant a thorough investigation of the spatial and temporal changes in the intrinsic excitability of CA1 pyramidal neurons across developmental time. Accordingly, in this study, I have characterized the intrinsic electrophysiological properties of CA1 pyramidal neurons from acute hippocampal slices prepared from the DHC and VHC throughout an approximately 3-week developmental period (P14-P37). DHC and VHC neurons exhibited distinct intra-region changes (DHC or VHC) and inter-region differences (DHC versus VHC) in their intrinsic electrophysiological properties, which yielded two developmental timelines: (a) a common developmental timeline describing changes observed in both DHC and VHC neurons, and (b) a differential developmental timeline highlighting unique features observed in DHC neurons. Specifically, DHC neurons exhibited significant inter-region differences in RMP, input resistance, threshold, and spike frequency adaptation relative to VHC neurons, as well as an intra-region change in the rebound slope (a proxy for Ih ). These observations both integrate and reconcile previous work performed with rats at different developmental stages and suggest a distinct developmental trajectory for DHC neurons that might shed light on the normal physiological functions and disease susceptibility of the DHC.

Carbamazepine-induced suppression of repetitive firing in CA1 pyramidal neurons is greater in the dorsal hippocampus than the ventral hippocampus.

Medial temporal lobe epilepsy (mTLE)-the most common form of focal epilepsy-is defined by recurrent partial seizures originating within the medial temporal lobe. Such seizures are commonly associated with the anterior hippocampus (as opposed to the posterior hippocampus), and refractory to the currently available anti-epileptic drugs (AED) for about one third of patients. Unfortunately, the mechanisms driving seizure generation and AED efficacy along the longitudinal hippocampal axis remain poorly understood. Recently, several groups investigating differences in excitability along the rodent longitudinal hippocampal axis have demonstrated that CA1 pyramidal neurons from the rodent ventral hippocampus (the rodent homolog of the human anterior hippocampus) are intrinsically more excitable than their dorsal counterparts (the rodent homolog of the human posterior hippocampus). This phenotypic difference is accompanied by significant differences in gene expression along the longitudinal hippocampal axis, which include gene products-such as voltage-gated sodium channel ß-subunits-known to influence AED efficacy. Given this phenotypic heterogeneity, and the differential expression of gene products known to influence anti-epileptic drug efficacy, we sought to investigate the efficacy of the classical use-dependent sodium channel blocker, carbamazepine, in CA1 pyramidal neurons across the longitudinal hippocampal axis. Accordingly, we performed whole-cell current-clamp recordings on CA1 pyramidal neurons from acute hippocampal slices prepared from the dorsal and ventral hippocampus, and found that acute exposure to 100 µM carbamazepine induced a significantly greater suppression of repetitive firing for dorsal neurons relative to ventral neurons by inducing profound spike frequency adaptation (SFA). Moreover, we observed a small, but significant depolarization of resting membrane potential (RMP) for dorsal neurons (but not ventral neurons), following exposure to carbamazepine. Together, these observations demonstrate that carbamazepine's effect is concentrated in the dorsal hippocampus, which could provide meaningful insight into the side effect profile of carbamazepine (and related anti-epileptic drugs) in non-epileptic tissue, and inform future work investigating the mechanisms of carbamazepine resistance in epileptic tissue.

Muscle Strength, Power, and Torque Deficits in Children With Type SS Sickle Cell Disease.

In African-American children aged 5 to 17 years with and without type SS sickle cell disease (SCD-SS), dominant hand maximal handgrip strength, peak power, and plantar flexion isometric maximal voluntary contraction (MVC) torque were compared with adjustments for body size and composition. Children with SCD-SS (n=21; age, 11±1 y) compared with healthy control children (n=23; 10±1 y) did not differ by age, sex, or maturation stage, but had significantly lower Z scores for height, weight, body mass index, arm circumference, upper arm muscle area, and lean mass-for-height. Children with SCD-SS had significantly lower unadjusted handgrip strength (16±2 vs. 23±2 kg, P<0.01), peak power (1054±107 vs. 1488±169 W, P<0.04) and MVC torques at 2 angles (10 degrees: 27±3 vs. 42±5 Nm; 20 degrees: 21±3 vs. 34±4 Nm; all P<0.05). Performance decrements persisted when handgrip strength was adjusted for lean body mass and fat mass explaining 66% of the variance; peak power adjusted for age, lean body mass, fat mass, and height explaining 91% of the variance; and the highest MVC torque (10-degree angle) adjusted for left leg length, lean mass-for-height, and fat mass-for-height Z scores explaining 65% of the variance. This suggests additional factors contribute to the attenuated anaerobic performance.

Effect of Oral Lipid Matrix Supplement on Fat Absorption in Cystic Fibrosis: A Randomized Placebo-Controlled Trial.

Pancreatic enzyme therapy does not normalize dietary fat absorption in patients with cystic fibrosis and pancreatic insufficiency. Efficacy of LYM-X-SORB (LXS), an easily absorbable lipid matrix that enhances fat absorption, was evaluated in a 12-month randomized, double-blinded, placebo-controlled trial with plasma fatty acids (FA) and coefficient of fat absorption (CFA) outcomes. A total of 110 subjects (age 10.4 ±â€Š3.0 years) were randomized. Total FA increased with LXS at 3 and 12 months (+1.58, +1.14 mmol/L) and not with placebo (P = 0.046). With LXS, linoleic acid (LA) increased at 3 and 12 months (+298, +175 nmol/mL, P ≤ 0.046), with a 6% increase in CFA (P < 0.01). LA increase was significant in LXS versus placebo (445 vs 42 nmol/mL, P = 0.038). Increased FA and LA predicted increased body mass index Z scores. In summary, the LXS treatment improved dietary fat absorption compared with placebo as indicated by plasma FA and LA and was associated with better growth status.

Choline Supplementation With a Structured Lipid in Children With Cystic Fibrosis: A Randomized Placebo-Controlled Trial.

BACKGROUND: Choline depletion is seen in cystic fibrosis (CF) and pancreatic insufficiency in spite of enzyme treatment and may result in liver, fatty acid, and muscle abnormalities. This study evaluated the efficacy and safety of an easily absorbed choline-rich structured lipid (LYM-X-SORB™ [LXS]) to improve choline status. METHODS: Children with CF and pancreatic insufficiency were randomized to LXS or placebo in a 12-month double blind trial. Dietary choline intake, plasma cholines, plasma and fecal phospholipids, coefficient of fat absorption, pulmonary function, growth status, body composition, and safety measures were assessed. Magnetic resonance spectroscopy for calf muscle choline and liver fat were assessed in a subgroup and compared with a healthy comparison group matched for age, sex, and body size. RESULTS: A total of 110 subjects were enrolled (age 10.4 ±â€Š3.0 years). Baseline dietary choline, 88% recommended, increased 3-fold in the LXS group. Plasma choline, betaine, and dimethylglycine increased in the LXS but not placebo (P = 0.007). Plasma lysophosphatidylcholine and phosphatidylcholine increased, and fecal phosphatidylcholine/phosphatidylethanolamine ratio decreased (P ≤ 0.05) in LXS only, accompanied by a 6% coefficient of fat absorption increase (P = 0.001). Children with CF had higher liver fat than healthy children and depleted calf muscle choline at baseline. Muscle choline concentration increased in LXS and was associated with improvement in plasma choline status. No relevant changes in safety measures were evident. CONCLUSIONS: LXS had improved choline intake, plasma choline status, and muscle choline stores compared with placebo group. The choline-rich supplement was safe, accepted by participants, and improved choline status in children with CF.

Mapping the electrophysiological and morphological properties of CA1 pyramidal neurons along the longitudinal hippocampal axis.

Differences in behavioral roles, anatomical connectivity, and gene expression patterns in the dorsal, intermediate, and ventral regions of the hippocampus are well characterized. Relatively fewer studies have, however, focused on comparing the physiological properties of neurons located at different dorsoventral extents of the hippocampus. Recently, we reported that dorsal CA1 neurons are less excitable than ventral neurons. There is little or no information for how neurons in the intermediate hippocampus compare to those from the dorsal and ventral ends. Also, it is not known whether the transition of properties along the dorsoventral axis is gradual or segmented. In this study, we developed a statistical model to predict the dorsoventral position of transverse hippocampal slices. Using current clamp recordings combined with this model, we found that CA1 neurons in dorsal, intermediate, and ventral hippocampus have distinct electrophysiological and morphological properties and that the transition in most (but not all) of these properties from the ventral to dorsal end is gradual. Using linear and segmented regression analyses, we found that input resistance and resting membrane potential changed linearly along the V-D axis. Interestingly, the transition in resonance frequency, rebound slope, dendritic branching in stratum radiatum, and action potential properties was segmented along the V-D axis. Together, the findings from this study highlight the heterogeneity in CA1 neuronal properties along the entire longitudinal axis of hippocampus.

Safety and Efficacy of High-dose Daily Vitamin D3 Supplementation in Children and Young Adults With Sickle Cell Disease.

Suboptimal vitamin D (vit D) status (<32 ng/mL) is ubiquitous among African American children with type SS sickle cell disease (SCD-SS). The vit D supplemental dose to normalize vit D status is unknown. Five to 20-year-old African American children with (n=21) and without (n=23) SCD-SS were randomized to vit D3 supplementation (4000 or 7000 IU/d) and evaluated at 6 and 12 weeks for changes in vit D and SCD status. A dose was considered unsafe if serum calcium was elevated associated with elevated serum 25 hydroxyvitamin D (25(OH)D). At baseline 95% of subjects with SCD-SS and 87% of healthy controls had suboptimal vit D status (mean±SD, 19.2±7.2 and 22.3±9.3 ng/mL, respectively). After 12 weeks supplementation, both D3 doses were safe and well tolerated. Neither group achieved the a priori efficacy criterion of 25(OH)D≥32 ng/mL in >80% of subjects (45% in SCD-SS and 63% in controls). However, for both subjects with SCD-SS and healthy subjects by 12 weeks, deficient (<20 ng/mL) vit D status was eliminated only in those receiving 7000 IU/d. For subjects with SCD-SS, by 12 weeks there was a significant (all P<0.05) increase in fetal hemoglobin, decrease in high-sensitivity C-reactive protein, and reduction in the percentage of subjects with a high platelet count.

High-dose vitamin D3 supplementation in children and young adults with HIV: a randomized, placebo-controlled trial.

BACKGROUND: Suboptimal vitamin D status is prevalent in HIV-infected patients and associated with increased risk of disease severity and morbidity. We aimed to determine 12-month safety and efficacy of daily 7000 IU vitamin D3 (vitD3) versus placebo to sustain increased serum 25-hydroxyvitamin D (25(OH)D) and improve immune status in HIV-infected subjects. METHODS: This was a double-blind trial of perinatally acquired HIV (PHIV)-infected subjects or behaviorally acquired HIV (BHIV)-infected subjects (5.0-24.9 years). Safety, 25(OH)D-related parameters and immune status were assessed at baseline, 3, 6 and 12 months. RESULTS: Fifty-eight subjects enrolled (67% male, 85% African American and 64% BHIV) and 50 completed with no safety concerns. In unadjusted analyses, there were no differences between randomization groups at baseline; at 3, 6 and 12 months, 25(OH)D was higher with supplementation than baseline and higher than with placebo (P < 0.05). In adjusted mixed models, in the supplementation group, the fixed effect of 25(OH)D was higher (P < 0.001). Percentage of naive T-helper cells (Th naive%) were significantly (P < 0.01) and T-helper cells (CD4%) marginally (P < 0.10) increased with supplementation in those taking highly active antiretroviral therapy (HAART), and RNA viral load was reduced (P ≤ 0.05). In exploratory linear models, change in 25(OH)D predicted RNA viral load at 3 and 12 months and CD4% at 3 months (P < 0.05). CONCLUSIONS: Daily 7000 IU vitD3 for 12 months was safe in HIV-infected subjects and effective in increasing 25(OH)D. Supplementation improved some clinically important HIV immune markers in subjects on HAART. Adjunct therapy with high-dose, daily vitD3 for HIV-infected subjects and for those on/off HAART requires further investigation.

Gene expression profiling of 49 human tumor xenografts from in vitro culture through multiple in vivo passages--strategies for data mining in support of therapeutic studies.

BACKGROUND: Development of cancer therapeutics partially depends upon selection of appropriate animal models. Therefore, improvements to model selection are beneficial. RESULTS: Forty-nine human tumor xenografts at in vivo passages 1, 4 and 10 were subjected to cDNA microarray analysis yielding a dataset of 823 Affymetrix HG-U133 Plus 2.0 arrays. To illustrate mining strategies supporting therapeutic studies, transcript expression was determined: 1) relative to other models, 2) with successive in vivo passage, and 3) during the in vitro to in vivo transition. Ranking models according to relative transcript expression in vivo has the potential to improve initial model selection. For example, combining p53 tumor expression data with mutational status could guide selection of tumors for therapeutic studies of agents where p53 status purportedly affects efficacy (e.g., MK-1775). The utility of monitoring changes in gene expression with extended in vivo tumor passages was illustrated by focused studies of drug resistance mediators and receptor tyrosine kinases. Noteworthy observations included a significant decline in HCT-15 colon xenograft ABCB1 transporter expression and increased expression of the kinase KIT in A549 with serial passage. These trends predict sensitivity to agents such as paclitaxel (ABCB1 substrate) and imatinib (c-KIT inhibitor) would be altered with extended passage. Given that gene expression results indicated some models undergo profound changes with in vivo passage, a general metric of stability was generated so models could be ranked accordingly. Lastly, changes occurring during transition from in vitro to in vivo growth may have important consequences for therapeutic studies since targets identified in vitro could be over- or under-represented when tumor cells adapt to in vivo growth. A comprehensive list of mouse transcripts capable of cross-hybridizing with human probe sets on the HG-U133 Plus 2.0 array was generated. Removal of the murine artifacts followed by pairwise analysis of in vitro cells with respective passage 1 xenografts and GO analysis illustrates the complex interplay that each model has with the host microenvironment. CONCLUSIONS: This study provides strategies to aid selection of xenograft models for therapeutic studies. These data highlight the dynamic nature of xenograft models and emphasize the importance of maintaining passage consistency throughout experiments.

Effect of a dietary intervention on growth and energy expenditure in children with cystic fibrosis.

BACKGROUND: The study aim was to determine the effect of a dietary intervention on growth, body composition and resting energy expenditure (REE) in children with cystic fibrosis (CF) and pancreatic insufficiency (PI) in a randomized, double blind, placebo-controlled trial. METHODS: Subjects (5 to 17 yrs) participated in a 12-month trial of the organized lipid matrix LYM-X-SORB™ (LXS) vs. placebo dietary supplements with similar calories, total fat and fatty acids. Dietary intake was assessed using 3-day weighed food records. Height (HAZ), weight (WAZ), BMI (BMIZ), mid-upper arm muscle (UAMAZ) and fat area (UAFAZ) Z-scores were calculated. Fat mass (FM) and fat-free mass (FFM) were obtained by whole body DXA. REE (kcal/d) was evaluated by indirect calorimetry at baseline, 3 and 12 months and %REE calculated using Schofield equations. No growth or REE differences were observed between LXS and placebo groups so data were pooled for analysis. RESULTS: 63 children (57% males, age 10.6 ± 2.9 yr, 43% receiving LXS) completed REE measurements. Caloric intake increased from a median of 2502 [1478, 4909] to 2616 [1660, 4125] kcal/d at 12 months. HAZ, WAZ and UAMAZ increased (p < 0.05) over 12 months. Mean REE was 109 ± 8% predicted at baseline and 107 ± 9% at 12 months (p < 0.05). REE (kcal/d) adjusted for FFM and FM decreased over 12 months ([mean ± SE] -31 ± 12 kcals, p < 0.01), significant only in males (-49 ± 16 kcals, p < 0.01). CONCLUSIONS: Over a 12 month nutrition intervention with either LXS or placebo, the growth status, muscle stores and REE improved. Sustained increased energy intake improved energy metabolism, growth and nutritional status in school age children with CF, PI and mild lung disease.

Vitamin B(12) status in children with cystic fibrosis and pancreatic insufficiency.

OBJECTIVES: Unexpectedly high serum B12 concentrations were noted in most study subjects with cystic fibrosis (CF) and pancreatic insufficiency (PI) participating in a nutrition intervention at the baseline evaluation. The objectives of this study were to determine dietary, supplement-based, and enzyme-based B12 intake, serum B12 concentrations, and predictors of vitamin B12 status in children with CF and PI. STUDY DESIGN: Serum B12 status was assessed in subjects (5-18 years) and categorized as elevated (serum B12 above reference range for age and sex [Hi-B12]) or within reference range (serum B12 within reference range for age and sex) for age and sex. Serum homocysteine, plasma B6, red blood cell folate, height, weight, and body mass index z scores, pulmonary function, energy, and dietary and supplement-based vitamin intake were assessed. RESULTS: A total of 106 subjects, mean age 10.4 ±â€Š3.0 years, participated in the study. Median serum B12 was 1083 pg/mL, with 56% in the Hi-B12 group. Dietary and supplement-based B12 intakes were both high representing 376% and 667% recommended dietary allowance (RDA), respectively. The Hi-B12 group had significantly greater supplement-based B12 intake than the serum B12 within reference range for age and sex group (1000% vs 583% RDA, P < 0.001). Multiple logistic regression analysis showed that high supplement-based B12 intake and age >12 years increased the risk of Hi-B12, whereas higher forced expiratory volume at 1 second (FEV1) decreased the risk (pseudo-R = 0.18, P < 0.001). CONCLUSIONS: Serum B12 was elevated in the majority of children with CF and PI. Supplement-based B12 intake was 6 to 10 times the RDA, and strongly predicted elevated serum B12 status. The health consequences of lifelong high supplement-based B12 intake and high serum B12 are unknown and require further study, as does the inversed correlation between serum B12 and forced expiratory volume at 1 second.

Fat-soluble vitamins in cystic fibrosis and pancreatic insufficiency: efficacy of a nutrition intervention.

OBJECTIVES: The aim of the study was to assess the impact of LYM-X-SORB (LXS), an organized lipid matrix that has been shown to be absorbable without pancreatic enzyme therapy on fat-soluble vitamin status in children with cystic fibrosis (CF) and pancreatic insufficiency (PI). METHODS: Children with CF and PI were randomized to daily LXS or an isocaloric placebo comparison supplement for 12 months. Serum vitamins A (retinol), D (25-hydroxyvitamin D[25D]), E (α-tocopherol, α-tocopherol:cholesterol ratio), and K (percentage of undercarboxylated osteocalcin [%ucOC] and plasma proteins induced by vitamin K absence factor II [PIVKA II]) were assessed at baseline and 12 months. Dietary intake was determined using 3-day weighed food records and supplemental vitamin intake by a comprehensive questionnaire. RESULTS: A total of 58 subjects (32 boys, age 10.3 ± 2.9 years [mean ± standard deviation]) with complete serum vitamin, dietary and supplemental vitamin data were analyzed. After adjusting for dietary and supplemental vitamin intake, serum retinol increased 3.0 ± 1.4 µg/dL (coefficient ± standard error) (adjusted R2 = 0.02, P = 0.03) and vitamin K status improved as demonstrated by a decreased percentage of undercarboxylated osteocalcin of -6.0% ± 1.6% by 12 months (adjusted R2 = 0.15, P < 0.001). These changes occurred in both the LXS and placebo comparison groups. No changes in serum 25D or α-tocopherol were detected. Both nutrition interventions increased caloric intake a mean of 83 ± 666 kcal/day by 12 months. CONCLUSIONS: Vitamins A and K status improved, whereas vitamins D and E status was unchanged during 12 months of LXS and isocaloric placebo comparison supplement in children with CF and PI.

Safety and Efficacy of High-Dose Daily Vitamin D3 Supplementation in Children and Young Adults Infected With Human Immunodeficiency Virus.

BACKGROUND: Suboptimal vitamin D (vitD) status is common in children and young adults infected with human immunodeficiency virus (HIV). The vitD supplemental dose needed to normalize vitD status in this population is unknown. METHODS: In this double-blind trial, subjects infected with HIV ages 8.3 to 24.9 years were randomized to vitD3 supplementation of 4000 IU/day or 7000 IU/day and evaluated at 6 and 12 week for changes in vitD status and HIV indicators. A dose was considered unsafe if serum calcium was elevated (above age and sex-specific range) associated with elevated serum 25 hydroxyvitamin D (25(OH)D); >160 ng/mL). RESULTS: At baseline, 95% of subjects (n = 44; 43% with perinatally acquired HIV, 57% with behaviorally acquired HIV) had a suboptimal serum 25(OH)D concentration of <32 ng/mL (mean ± standard deviation, 19.3 ± 7.4; range, 4.4-33.6 ng/mL). After 12 weeks (main outcome) of D3 supplementation, both D3 doses were safe and well tolerated, with no evidence of elevation of serum calcium concentrations or deterioration in HIV immunologic or virologic status. Sufficient vitD status, defined as serum 25(OH)D ≥32 ng/mL, was achieved in 81% of all subjects, and only the 7000 IU/day group (86%) achieved this a priori efficacy criterion in >80% of subjects. Change in serum 25(OH)D did not differ between HIV acquisition groups. CONCLUSIONS: A 7000 IU/day D3 supplementation was safe and effective in children and young adults infected with HIV.

Differential expression of HCN subunits alters voltage-dependent gating of h-channels in CA1 pyramidal neurons from dorsal and ventral hippocampus.

The rodent hippocampus can be divided into dorsal (DHC) and ventral (VHC) domains on the basis of behavioral, anatomical, and biochemical differences. Recently, we reported that CA1 pyramidal neurons from the VHC were intrinsically more excitable than DHC neurons, but the specific ionic conductances contributing to this difference were not determined. Here we investigated the hyperpolarization-activated current (I(h)) and the expression of HCN1 and HCN2 channel subunits in CA1 pyramidal neurons from the DHC and VHC. Measurement of Ih with cell-attached patches revealed a significant depolarizing shift in the V(1/2) of activation for dendritic h-channels in VHC neurons (but not DHC neurons), and ultrastructural immunolocalization of HCN1 and HCN2 channels revealed a significantly larger HCN1-to-HCN2 ratio for VHC neurons (but not DHC neurons). These observations suggest that a shift in the expression of HCN1 and HCN2 channels drives functional changes in I(h) for VHC neurons (but not DHC neurons) and could thereby significantly alter the capacity for dendritic integration of these neurons.

Blood lead concentration is not altered by high-dose vitamin D supplementation in children and young adults with HIV.

OBJECTIVES: Optimal vitamin D status is known to have beneficial health effects and vitamin D supplements are commonly used. It has been suggested that vitamin D supplementation may increase blood lead in children and adults with previous lead exposure. The objective was to determine the safety regarding lead toxicity during 12 weeks of high-dose vitamin D3 supplementation in children and young adults with human immunodeficiency virus (HIV). METHODS: Subjects with HIV (8-24 years) were randomized to vitamin D3 supplementation of 4000 or 7000 IU/day and followed at 6 and 12 weeks for changes in serum 25-hydroxy vitamin D (25D) and whole-blood lead concentration. This was a secondary analysis of a larger study of vitamin D3 supplementation in children and adolescents with HIV. RESULTS: In 44 subjects (75% African American), the baseline mean ± standard deviation serum 25D was 48.3±18.6 nmol/L. Fifty percent of subjects had baseline serum 25D <50.0 nmol/L. Serum 25D increased significantly with D3 supplementation during the 12 weeks. No subject had a whole-blood lead >5.0 µg/dL at baseline or during subsequent visits. Whole-blood lead and 25D were not correlated at baseline, and were negatively correlated after 12 weeks of supplementation (P=0.014). Whole-blood lead did not differ between those receiving 4000 and 7000 IU of vitamin D3. CONCLUSIONS: High-dose vitamin D3 supplementation and the concomitant increased serum 25D did not result in increased whole-blood lead concentration in this sample of children and young adults living in a northeastern urban city.

No improvement in suboptimal vitamin A status with a randomized, double-blind, placebo-controlled trial of vitamin A supplementation in children with sickle cell disease.

BACKGROUND: Suboptimal vitamin A status is prevalent in children with type SS sickle cell disease (SCD-SS) and is associated with hospitalizations and poor growth and hematologic status. The supplemental vitamin A dose that optimizes suboptimal vitamin A status in this population is unknown. OBJECTIVE: The efficacy of Recommended Dietary Allowance (RDA) doses (based on age and sex) of vitamin A (300, 400, or 600 µg retinyl palmitate/d) or vitamin A + zinc (10 or 20 mg zinc sulfate/d) compared with placebo to optimize vitamin A status was assessed in children aged 2.0-12.9 y with SCD-SS and a suboptimal baseline serum retinol concentration (<30 µg/dL). DESIGN: In this randomized, double-blind, placebo-controlled trial, vitamin A status (serum retinol, prealbumin, retinol-binding protein, and relative-dose-response test) and disease-related illness events were assessed. RESULTS: Twelve months of vitamin A supplementation at the doses recommended for healthy US children (based on age and sex) failed to improve serum retinol values in either group (vitamin A: n = 23; vitamin A + zinc: n = 18) compared with placebo (n = 21). By 12 mo, the increase (±SD) in serum retinol (3.6 ± 2.8 µg/dL) in those taking 600 µg vitamin A/d was significantly different from the decrease (±SD; -2.8 ± 2.4 µg/dL) in those taking 300 µg/d, which possibly suggests a dose-response relation (P < 0.05) with RDA doses. CONCLUSIONS: Compared with placebo, 12 mo of vitamin A supplementation at the RDA for healthy children did not improve serum retinol values in children with SCD-SS, which possibly suggests that higher doses are needed. However, the existence of alternative conclusions emphasizes the need for future research.