Tetrahydrobiopterin (BH(4)) is a naturally occurring cofactor essential for critical metabolic pathways. Studies suggest that BH(4) supplementation may ameliorate autism symptoms; the biological mechanism for such an effect is unknown. To help understand the relation between central BH(4) concentration and systemic metabolism and to develop a biomarker of central BH(4) concentration, the relati...

The reactivity of hydrazine in the presence of diborane has been investigated using ab initio quantum chemical computations (MP2 and CCSD(T) methods with the aug-cc-pVTZ basis set). Portions of the relevant potential energy surface were constructed to probe the formation mechanism of the hydrazine diborane (BH(3)BH(3)NH(2)NH(2)) and hydrazine bisborane (BH(3)NH(2)NH(2)BH(3)). The differences be...

black henbane (bh) or hyoscyamus niger, has been used as a medicine since last centuries and has been described in all traditional medicines. it applies as a herbal medicine, but may induce intoxication accidentally or intentionally. all part of bh including leaves, seeds and roots contain some alkaloids such as hyoscyamine, atropine, tropane and scopolamine. bh has pharmacological effects like...

Augmentation of superoxide levels has been linked to impaired relaxation in hypertension, diabetes and hypercholesterolaemia. Purified endothelial nitric oxide synthase (eNOS) generates superoxide under limited availability of 5,6,7,8-tetrahydrobiopterin (BH(4)). Thus alterations in endothelial BH(4) levels have been postulated to stimulate superoxide production from eNOS. This possibility was ...

OBJECTIVES To determine the relationship of child behavioral health (BH) screening results to receipt of BH services in Massachusetts Medicaid (MassHealth) children. METHODS After a court decision, Massachusetts primary care providers were mandated to conduct BH screening at well-child visits and use a Current Procedural Terminology code along with a modifier indicating whether a BH need was ...

BACKGROUND Arthroscopic shoulder surgery has been performed in the sitting position under interscalene block (ISB). Bradycardia hypotension (BH) episodes have a reported incidence of 13-29% in this setting. We performed a retrospective study to investigate contributing factors to the occurrence of BH episodes. METHODS According to BH episodes, we divided 63 patients into two groups: BH group ...

The aim of this study was to characterize the mechanism of the chemical interaction between L-ascorbic acid (ASC) and tetrahydrobiopterin (BH(4)) in vitro and to examine its effect on the activity of endothelial nitric oxide synthase (eNOS) in first trimester human placentae. At room temperature, in Tris-HCl buffer (pH 7.4), both ASC and BH(4) were readily oxidized by dissolved O(2) or H(2)O(2)...

Tetrahydrobiopterin (BH₄) is a co-factor required for catalytic activity of nitric oxide synthase (NOS) and amino acid-monooxygenases, including phenylalanine hydroxylase. BH4 is unstable: during oxidative stress it is non-enzymatically oxidized to dihydrobiopterin (BH₂), which inhibits NOS. Depending on BH₄ availability, NOS oscillates between NO synthase and NADPH oxidase: as the BH₄/BH₂ rati...

OBJECTIVES We investigated whether abnormal pteridine metabolism is related to coronary endothelial dysfunction in insulin-resistant subjects. BACKGROUND Depletion of tetrahydrobiopterin (BH(4)) and elevation of the 7,8-dihydrobiopterin (BH(2)) (activating and inactivating cofactors of nitric oxide synthase [NOS], respectively) contribute to impairment of NO-dependent vasodilation through red...

BACKGROUND Whilst a reduction in blood phenylalanine (Phe) levels is essential in patients with PKU, a decrease in Phe/Tyrosine (Tyr) ratio and fluctuations in blood Phe levels over time have been recently associated with improved neuropsychological outcome. The aim of this study was to identify if Tetrahydrobiopterin (BH(4)) offers additional benefit based on the assumption that these 2 factor...