Biomedical subjects

Futoshi Yazama

Publications and source records attributed to Futoshi Yazama.

6 recordsLinked to original sources

PubMed2006

Binding of glutamate receptor delta2 to its scaffold protein, Delphilin, is regulated by PKA.

The glutamate receptor delta2 (GluRdelta2) is selectively expressed in cerebellar Purkinje cells and plays an important role in motor learning, motor coordination, and long-term depression. Delphilin is identified as a GluRdelta2-interacting protein, selectively expressed in Purkinje cell-parallel fiber synapses, and specifically interacts with the GluRdelta2 C-terminus via its PDZ domain. Here, surface plasmon resonance analyses showed that Delphilin PDZ bound to GluRdelta2 C-terminal peptide (DPDRGTSI), but not to its phosphopeptides (DPDRGphosphoTSI and DPDRGTphosphoSI). We showed the incorporation of phosphate into threonine at -2 (-2T) and serine at -1 (-1S) of GluRdelta2 C-terminus by cAMP-dependent protein kinase (PKA) in vitro. In the experiments using heterologous expression system, Delphilin coimmunoprecipitated with GluRdelta2 was dramatically decreased under the condition with forskolin and isobutylmethylxanthine, which led to cAMP-dependent phosphorylation by PKA. Thus, phosphorylation of -2T and/or -1S of GluRdelta2 C-terminus by PKA may regulate the binding of GluRdelta2 to its scaffolding protein, Delphilin.

Binding Sites↗

PubMed2006

Abnormal spermatogenesis in mice unable to synthesize ascorbic acid.

Although exposure to environmental toxicants, including endocrine-disrupting chemicals, is thought to be a possible cause of male infertility, the pathogenesis of male reproductive disorders remains unclear. In the present study, we used Gulo-/- mutant mice, which are unable to synthesize ascorbic acid, to study the importance of dietary vitamin C (VC) on spermatogenesis. Regular chow containing approximately 110 mg/kg VC is unable to support the growth of these mutant mice, but a VC supplement in their drinking water (330 mg/L) is able to ameliorate the VC deficiency. Testes of Gulo-/- mutants born from heterozygous mothers without VC supplement (VC-deficient mice) and those born from mothers given a VC supplement (VC-sufficient mice) were examined by morphological and biochemical analyses. Morphological analysis revealed that apoptosis of spermatocytes occurred frequently in VC-deficient mice at 20 days of age. Two-dimensional electrophoresis analysis revealed the specific disappearance of heat-shock protein (Hsp) 70 in the testes of 20-day-old VC-deficient mice. In the present study, the relationship between the apoptosis of spermatocytes and Hsp70 in VC-deficient mice is discussed.

Animals↗

PubMed2005

Differential development of TRPV1-expressing sensory nerves in peripheral organs.

In mouse ontogeny, neurons immunoreactive for transient receptor potential vanilloid receptor 1 (TRPV1) were observed primarily in the dorsal root ganglia (DRG) at embryonic day 13 (E13). In the embryonic period, the number of TRPV1(+) neurons decreased, but then gradually increased postnatally. Some of TRPV1(+) neurons were also immunoreactive for calcitonin gene-related peptide (CGRP). At postnatal day 7 (P7), 66% of CGRP(+) neurons were TRPV1(+), and 55% of TRPV1(+) neurons were also CGRP(+) in the L4 DRG. In the peripheral organs, TRPV1-immunorective nerve fibers were transiently observed in the skin at E14. They were also observed in the urinary tract at E14, and in the rectum at E15. Many TRPV1(+) nerve fibers in these organs were also CGRP(+). At P1, TRPV1(+) nerve fibers were observed in the respiratory organs, and to a lesser extent in the stomach, colon, skin, and skeletal muscles. The number of TRPV1(+) nerve fibers on each organ gradually increased postnatally. At P7, TRPV1(+) nerve fibers were also observed in the small intestine and kidneys. The percentage of total TRPV1(+) nerve fibers that co-localized with CGRP was greater in most organs at P7 than at P1. The present results indicate that TRPV1 expression on peripheral processes differs among organs. The differential time course of TRPV1 expression in the cell bodies might be related to the organs to which they project. Co-localization of TRPV1 with CGRP on nerve fibers also varies among organs. This suggests that the TRPV1-mediated neuropeptide release that occurs in certain pathophysiologic conditions also varies among organs.

Animals↗

PubMed2004

Full-term development of hamster embryos produced by injection of round spermatids into oocytes.

The golden hamster is a mammal in which microinjection of round spermatids into oocytes (ROSI) was first attempted. However, no live ROSI offspring have ever been obtained in this species. This is the first report of live hamster offspring obtained by round spermatid injection. Over 90% of oocytes, injected with round spermatids, were activated without any additional stimulation. The proportion of the oocytes that were fertilized normally and that developed to morulae and blastocysts was higher when the plasma membranes of the spermatids were broken before injection, as compared with when the membranes were left intact. Five percent of 57 ROSI morulae/blastocysts developed into live offspring after transfer to foster mothers.

Animals↗

PubMed2002

Bilateral persistent sciatic arteries in a Japanese man.

During student dissecting practice, a rare developmental anomaly showing persistent sciatic artery (PSA) was found in the bilateral lower limbs of a 74-year-old Japanese male cadaver. The PSA was a continuation of the internal iliac artery on both sides, did not anastomose with the perforating arteries and ended by anastomosing with the popliteal artery on both sides. The course and distribution of the PSA were relatively consistent with previous reports. In the present case, however, the PSA and inferior gluteal arteries existed simultaneously on both sides, despite the general assumption that the inferior gluteal artery is a remnant of sciatic artery regression.

Aged↗

PubMed2002

Role of matrix metalloproteinase-7 in angiogenesis associated with age-related macular degeneration.

To investigate the possible role of matrix metalloproteinase-7 in choroidal neovascularization associated with age-related macular degeneration, immunoelectron microscopy using ultrathin frozen sections and conventional transmission electron microscopy were performed in subfoveal fibrovascular membranes from patients with age-related macular degeneration. immunoelectron microscopy revealed that matrix metalloproteinase-7 was expressed within basal laminar deposits and amorphous materials around the retinal pigment epithelial cells. The results support a role for matrix metalloproteinase-7 in the development of choroidal neovascularization in age-related macular degeneration.

Age Factors↗