UGT1A1*28 detection using high-resolution agarose gel electrophoresis.

A new UGT1A1*28 detection method combining PCR and high-resolution agarose gel electrophoresis was developed. The viability of this method was demonstrated on 15 healthy adult volunteers. Subjects included 13 wild type homozygotes (86.7 %), 2 heterozygotes (13.3 %), and no mutant type homozygotes (0 %). The new UGT1A1*28 detection method results were fully consistent with DNA sequencing. PCR and agarose gel electrophoresis are common techniques with high-resolution agarose gels available commercially. These results support the clinical viability of this method potentially reducing UGT1A1*28 diagnosis complexity and cost.

Photoinduced electron transfer detection method for identifying UGT1A1*28 microsatellites.

During development of a novel detection method for the UDP-glucuronosyl transferase 1A1 (UGT1A1)*28, the fluorescence intensity of a dye conjugated to cytosine (C) at the end of a DNA strand decreased upon hybridization with guanine (G). This phenomenon is referred to as photoinduced electron transfer (PeT). Using this phenomenon, we devised a method for the naked-eye detection of UGT1A1*28 (thymine-adenine (TA)-repeat polymorphism). Fluorescently labeled single-stranded DNA (ssDNA) oligonucleotides (probes) were designed and hybridized with complementary strand DNAs (target DNAs). Base pair formation at the blunt end between fluorescently labeled C (probe side) and G (target side), induced dramatic fluorescence quenching. Additionally, when the labeled-CG pair formed near the TA-repeat sequence, different TA-repeat numbers were discriminated. However, obtaining enough target DNA for this probe by typical polymerase chain reaction (PCR) was difficult. To enable the practical use of the probe, producing sufficient target DNA remains problematic.

Separation and detection of D-/L-serine by conventional HPLC.

D-serine has a role as an endogenous allosteric agonist of N-methyl-D-aspartate (NMDA) receptor in the mammalian brain. In this study, we present a detailed description of our method that measures D-/L-serine by using conventional high performance liquid chromatography (HPLC). • We reacted D-serine and L-serine with ortho-phthalaldehyde (OPA) and N-acetyl-L-cysteine (NAC) to form diastereomeric isoindole derivatives, then we separated and detected them by conventional reversed phase HPLC with electrochemical detector (ECD). • We present typical measurement data of rat brain homogenate as an example of a convenient, appropriate method for measuring brain concentrations of D-serine. • Since many peaks appear in biological samples, we confirmed that the peaks were derived from serine by treating the sample with D-amino oxidase and catalase to decompose D-serine. As a results, one peak disappeared, suggesting that it is derived from D-serine.

D-serine metabolism in the medial prefrontal cortex, but not the hippocampus, is involved in AD/HD-like behaviors in SHRSP/Ezo.

Attention-deficit/hyperactivity disorder (AD/HD) is a mild neurodevelopmental disorder with inattention, hyperactivity, and impulsivity as its core symptoms. We previously revealed that an AD/HD animal model, juvenile stroke-prone spontaneously hypertensive rats (SHRSP/Ezo) exhibited functional abnormalities in N-methyl-D-aspartate (NMDA) receptors in the prefrontal cortex. D-serine is an endogenous co-ligand that acts on the glycine-binding site of NMDA receptors, which is essential for the physiological activation of NMDA receptors. We herein performed neurochemical and pharmacological behavioral experiments to elucidate dysfunctions in D-serine metabolism (namely, biosynthesis and catabolism) associated to AD/HD. The serine enantiomers ratio (D-serine/D-serine + L-serine, DL ratio) in the medial prefrontal cortex (mPFC) and hippocampus (HIP) was lower in SHRSP/Ezo than in its genetic control. The level of D-amino acid oxidase (DAAO, D-serine degrading enzyme) was higher in the mPFC, and the level of serine racemase (SR, D-serine biosynthetic enzyme), was lower in the HIP in SHRSP/Ezo. Thus, changes in these enzymes may contribute to the lower DL ratio of SHRSP/Ezo. Moreover, a microinjection of a DAAO inhibitor into the mPFC in SHRSP/Ezo increased DL ratio and attenuated AD/HD-like behaviors, such as inattention and hyperactivity, in the Y-maze test. Injection into the HIP also increased the DL ratio, but had no effect on behaviors. These results suggest that AD/HD-like behaviors in SHRSP/Ezo are associated with an abnormal D-serine metabolism underlying NMDA receptor dysfunction in the mPFC. These results will contribute to elucidating the pathogenesis of AD/HD and the development of new treatment strategies for AD/HD.