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Biomedical subjects

J Murata

Publications and source records attributed to J Murata.

At least 127 records · Page 7Linked to original sources
PubMed1987

Effects of polyprenoic acid on thermal injury.

This study was designed to determine the effect of polyprenoic acid on wound healing in rats after thermal injury and to compare the effect with healing in vitamin A deficient controls and in retinol-fed vitamin A deficient rats. Both polyprenoic acid and retinol visibly accelerated wound healing after thermal injury. Both enhanced the induction of platelets in the peripheral blood but neutrophils were not affected by polyprenoic acid. Histologically, in the hypo-vitamin A rat, polyprenoic acid administration increased both capillary formation and also the production of fibroblasts and collagen deposition in the wound by comparison with control vitamin A deficient animals; similar effects were produced by retinol feeding. These results indicate that both polyprenoic acid and retinol can facilitate wound healing. 3H-thymidine incorporation into dermal tissues showed that in polyprenoid-fed rats capillaries multiplied 1.3 times, epithelial cells 2.1 times, and fibroblasts 2.0 times faster than those in vitamin A-deficient animals; 3H-thymidine incorporation was greater after polyprenoid feeding than after retinol feeding. Polyprenoid thus stimulates both collagen deposition and neo-vascularization within burns, and so accelerates healing.

Animals↗
PubMed1986

Ovarian membrane receptors for LH, FSH and prolactin during the menstrual cycle and in polycystic ovary syndrome.

To investigate the role of ovarian membrane receptors for LH, FSH and prolactin of patients with developing polycystic ovary (PCO) syndrome, seven patients were selected and the receptor function was studied in relation to changes of several serum hormone levels. The results were compared with those from individuals with regular menstrual cycles in the late follicular (LF; n = 6) and midluteal (ML; n = 6) phases. LH receptor binding in the normal cycle remained low (1.73 +/- 0.14 fmole/mg homogenate protein) in the LF phase and elevated 3 fold in the ML phase. LH receptors in the PCO patients maintained a higher binding level than that in the LF phase, being close to the ML level. FSH receptors were at a high level in the LF phase (4.09 +/- 0.40 fmole/mg homogenate protein), but decreased by 23% in the ML phase. In the PCO group the ovarian FSH receptor showed a high level, near to that in the LF phase. Prolactin receptors showed no significant changes among the two controls and PCO group. PCO patients showed increased levels of serum LH and testosterone and a raised ratio of estrone to estradiol, although there was no change in the serum FSH level. These data suggested that the LH receptor binding in PCO was not so low as to the LF level. A lack of the down-regulation mechanism of LH receptors, in spite of the high level of serum LH in PCO, might be one of the clues to elucidate the pathophysiological mechanism in developing PCO syndrome. Elevated levels of the gonadotropin receptors, especially FSH receptors, seem to be involved in the high incidence of ovarian hyperstimulation during hormone treatment.

Adult↗
PubMedDate not supplied

Anti-metastatic and anti-invasive effects of polymeric Arg-Gly-Asp (RGD) peptide, poly(RGD), and its analogues.

We have investigated the anti-metastatic and anti-invasive activities of polypeptide analogues based on the Arg-Gly-Asp (RGD) adhesive signal in fibronectin, poly(RGD), poly(RGDS)[Arg-Gly-Asp-Ser] and poly(RGDT)[Arg-Gly-Asp-Thr]. These polypeptides containing repetitive RGD sequences were able to inhibit experimental and spontaneous lung metastases of B16-BL6 cells more effectively than the corresponding monomer peptides. In the spontaneous metastasis model, multiple i.v. administrations of these polymeric peptides before or after surgical excision of the primary tumor resulted in a significant reduction of lung tumor colonies. However, there was no significant difference in ability to inhibit spontaneous lung metastasis among poly(RGD), poly(RGDS) and poly(RGDT), although the carboxy-terminal amino acid residue (i.e., Xaa in -RGDXaa-) has been shown to play an important role in the expression of cell adhesive character. The treatment with poly(RGD) substantially prolonged the survival time for mice injected s.c. with B16-BL6 melanoma as compared with the untreated control. We also found that the polypeptides were potently able to inhibit the invasion and migration of tumor cells in vitro. Since these polypeptide analogues showed no antigenicity in the host and had no toxic effect on tumor cells in vitro, they may be potentially useful in the prevention of cancer metastasis.

Amino Acid Sequence↗
PubMedDate not supplied

Inhibition of tumor angiogenesis by a synthetic cell-adhesive polypeptide containing the Arg-Gly-Asp (RGD) sequence of fibronectin, poly(RGD).

We have investigated the anti-angiogenic effect of a polymeric peptide based on the Arg-Gly-Asp (RGD) core sequence of fibronectin as a monomer unit, i.e., poly(RGD), in syngeneic mice and in vitro. Single intratumoral administration of poly(RGD) on day 0, 1 or 7 after tumor implantation achieved a significant reduction of B16-BL6 melanoma colonization in the lungs, but did not affect the size of the primary tumor at the time of amputation. The number of capillary blood vessels oriented toward the tumor mass increased during the early growth phase after the intradermal inoculation of the tumor. Poly(RGD) significantly inhibited the formation of tumor neovascularization when co-injected with the tumor cells or separately injected intratumorally or intravenously on day 1 or 3 after tumor inoculation. This inhibitory effect of poly(RGD) was dose-dependent. Poly(RGD) was able to inhibit the haptotactic migration of endothelial cells along a gradient of substratum-immobilized fibronectin but not laminin. Tumor-conditioned medium (CM) by itself did not act as a chemoattractant when it was added in the lower compartment of a Transwell chamber, but promoted the endothelial cell migration to immobilized fibronectin or laminin. Poly(RGD) inhibited the enhanced cell migration to fibronectin but not to laminin in response to CM. Thus, poly(RGD)-mediated inhibition of tumor metastasis may be partly due to the inhibition of tumor-induced angiogenesis at primary and secondary sites.

Animals↗
PubMedDate not supplied

Ultrastructural observations of small blood vessels in leprosy patients.

In lepromatous leprosy, blood vessels revealed the luminal protrusions of endothelial cells containing M. leprae and thickening of the basement membrane of endothelial and smooth cells. Endothelial projections with increased pinocytotic vesicles were more often encountered in lepromatous leprosy than in the other types of leprosy. On the other hand, in tuberculoid leprosy, the extensive rough endoplasmic reticulum suggesting protein synthesis was observed in the endothelial cells compared with the other types of leprosy and non-specific lesions. It seems that the blood vessels associated with hyperfunction and proliferation in the endothelium could aggravate the degenerative changes in peripheral nerve fibers including the Schwann cells.

Endothelium, Vascular↗