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Biomedical subjects

F Takahashi

Publications and source records attributed to F Takahashi.

At least 19 recordsLinked to original sources
PubMed1992

Diffuse nerve fiber layer loss in normal tension glaucoma.

14 eyes of 14 normal tension glaucoma (NTG) patients with the maximum intraocular pressure (IOP) > or = 19 mmHg and 16 eyes of 16 NTG patients with the maximum IOP < 19 mmHg were examined. All patients had a scotoma confined to the upper or lower hemifield. Eyes with the maximum IOP > or = 19 mmHg showed significantly diffuse retinal nerve fiber layer (RNFL) loss in the RNFL area corresponded to the spared visual hemifield as compared to those with the maximum IOP < 19 mmHg. The results suggests that, even in NTG, IOP may be an important factor causing optic nerve damage.

Female↗
PubMed1992

[Pharmacokinetic studies of menogaril (TUT-7) with rats].

Menogaril (TUT-7) is a novel antitumor antibiotic belonging to anthracyclines. The pharmacokinetic parameters derived from plasma concentration-time profiles after repeated (for 14 days) or single oral administration of TUT-7 to rats were found to be not significantly different by either administration schedule. The rats with artificial liver dysfunction were obtained by subcutaneous application of carbon tetrachloride (CCl4, 1 ml/kg) for 3 days. After oral administration of TUT-7 to the rats with CCl4-induced liver toxicity (3 daily administrations of 1mg/kg, S.C.), the maximum plasma concentrations (Cmax) and AUC of both the unchanged drug and its metabolite N-Demethyl menogaril, were increased. Also over all elimination was slower in animals with liver dysfunction.

Administration, Oral↗
PubMed1989

Experimental replantation of canine forelimbs after 78.5 hours of anoxia.

To assess the effect of ischemia on osteocyte survival and longitudinal growth in bone, one forelimb of eight puppies and seven dogs was amputated, perfused with iced Collins solution, maintained at 4 degrees C for 72 hours (78.5 hours total anoxia), and replanted. Five puppies were kept for 1 year to assess bone growth. Undergoing bone labeling on days 1, 8, and 15, the other animals were sacrificed at 22 days to assess osteocyte survival. Osteocytes survived replantation in all dogs and one puppy; most osteocytes died in two puppies. In five long-term puppies, central epiphyseal growth was disturbed, but the peripheral portions maintained nearly normal growth, with almost normal bone length being achieved at 1 year.

Animals↗
PubMed1988

Effect of alpha-methyl-p-tyrosine and an antiserum to rat growth hormone (GH)-releasing factor (GRF) on plasma GH secretory profile during a continuous infusion of human GRF in rats.

The effects of alpha-methyl-p-tyrosine (alpha-MT) and an antiserum specific to rat growth hormone-releasing factor (GRF) on growth hormone (GH) secretory profile during a 6-h continuous infusion of human GRF(1-44) NH2 were observed in unrestrained adult male Wistar rats. All rats were provided with two indwelling cannulae; one in the right atrium for undisturbed blood collection and the other in the inferior vena cava for 0.9% NaCl or GRF infusion. GRF was administered by an infusion pump at a dose of 50 ng/kg b.wt./min ma GH levels during baseline period were low with little fluctuation. GH secretion was augmented significantly during continuous GRF infusion in control rats but interpeak intervals remained unaltered. When an antiserum specific to rat GRF was administered, episodic GH secretion was abolished. In these rats, pulsatile GH secretion indistinguishable from that of control rats was observed in the continuous presence of human GRF. Although alpha-MT inhibited episodic GH secretion, alpha-MT-treated rats exhibited high-frequency, low-amplitude episodic GH secretion and elevated baseline levels during the stimulation. There were no differences in the amount of GH secreted during GRF infusion between rats that had received either alpha-MT or antiserum to rat GRF. Since GH secretion to GRF is determined largely by somatostatin, the results suggest that phasic release of somatostatin plays an important role in determining the rhythmicity of episodic GH secretion, and that it is modulated by alpha-MT but not by the immunoneutralization of GRF.

Animals↗
PubMed1988

Effect of testosterone on growth hormone secretion in female rats during a continuous infusion of growth hormone releasing factor.

The effect of testosterone on growth hormone (GH) secretory pattern during a 6-hour continuous infusion of human GH-releasing factor (GRF) (1-44) NH2 was observed in unrestrained adult female Wistar rats. Rats had been ovariectomized or sham operated 6 weeks previously. Three weeks after the ovariectomy, the rats received sesame oil or testosterone propionate at a dose of 1 or 2 mg s.c. daily for 21 days. All rats were provided with two indwelling cannulae: one in the right atrium for undisturbed blood collection and the other in the inferior vena cava for vehicle or GRF infusion. Vehicle or GRF was administered by an infusion pump at a dose of 50 ng/kg/min for 6 h. Serial blood specimens were obtained every 20 min. Sham-operated adult female Wistar rats exhibited a high-frequency, low-amplitude pulsatile GH secretion during a 6-hour vehicle infusion. When they received a 6-hour continuous infusion of GRF, the amplitudes of GH pulses and baseline GH values were markedly augmented, but the pulse frequency remained unaltered. The GH secretory pattern during a 6-hour vehicle infusion among ovariectomized rats was similar to that of sham-operated female rats, whereas the magnitude of elevation of GH pulse and baseline level in ovariectomized rats were significantly lower than in sham-operated rats. The ovariectomized female rats that had received 2 mg testosterone for 21 days showed a low-frequency, regularly timed, high-amplitude pulsatile GH secretion, and GH values during the intervening period were low. This GH secretory pattern was indistinguishable from that in adult male rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

The ability of oxygenated fluorocarbon solution to minimize ischemic skeletal muscle injury.

The amputated canine limb was used to create a devascularized skeletal-muscle-containing model. The extremity was perfused with one of several solutions or merely cooled as a preservative measure during the devascularized period and then replanted. Perfusion of the limb with oxygenated fluorocarbon solution minimized edema formation and leakage of skeletal muscle enzymes into the serum following revascularization as compared to the other perfusates or to mere cooling. Histopathologic changes within the revascularized muscle were also minimized by the oxygenated fluorocarbon perfusion. It is probable that these findings will correlate with improved function of replanted extremities or free muscle flaps. The applicability of these findings to human extremity replantation and free-flap transfer is postulated. However, long-term human studies will be necessary to assess the function of extremities and flaps perfused with this solution prior to its general use in extremity replantation and free-flap transfer.

Animals↗
PubMed1987

A radioimmunoassay for human pro-luteinizing hormone-releasing factor [pro-LRF(14-69)OH].

A radioimmunoassay (RIA) for human pro-LRF(14-69)OH was developed with an antiserum, generated in a rabbit, to [Tyr67]pro-LRF(47-67)NH2 conjugated to BSA. This antiserum bound 28-32% of [125I]pro-LRF(14-69)OH at a final dilution of 1:2500 and the binding was inhibited by pro-LRF(14-69)OH in a dose-dependent manner. The sensitivity of the RIA was 31.2-62.5 pg and the dose that inhibited 50% of the binding to the tracer was 280-320 pg. Intra- and inter-assay coefficients of variation at 50% inhibition were 8 and 12%, respectively. Neither LRF nor pro-LRF(14-37)OH was recognized by the antiserum. The dilution curve generated with human hypothalamic extract was parallel to that of pro-LRF(14-69)OH. In addition the extract yielded a major immunoreactive peak emerging in elution volumes concordant with [125I]pro-LRF(14-69)OH on Sephadex G-50 chromatography.

Antibody Specificity↗
PubMed1987

[An experimental study on the effect of fluorocarbon perfusion for the preservation of an amputated limb].

We assessed the ability of oxygenated fluorocarbon (chilled Fluosol-DA) to minimize the effect of ischemia on devascularized skeletal muscle of dog. 1) Short term follow-up study: Perfusion of the limb with Fluosol-DA solution significantly minimized edema formation and leakage of skeletal muscle enzymes (GOT, CPK) into the serum 5.5 hours after revascularization as compared to Collins sol., lactated Ringer's sol. or merely cooling. Histological finding showed that the Fluosol-DA group had significantly less hyaline degeneration and separation of the muscle fiber from the endomysium than the groups receiving Collins sol., lactated Ringer's sol. or merely cooling group. 2) Long term follow-up study: The Fluosol-DA group showed less enzyme elevation than the Collins sol. and lactated Ringer's sol. groups. Histologically, the Collins sol. and lactated Ringer's sol. group showed significant scarring compared to the Fluosol-DA group. It was concluded that perfusion with chilled Fluosol-DA was effective for preservation of devascularized skeletal muscle.

Amputation, Surgical↗
PubMed1985

Concentration-dependent sedimentation properties of ferritin: implications for estimation of iron contents of serum ferritins.

Serum ferritins from various sources sedimented at lower densities than tissue ferritins in sucrose gradient centrifugation systems. The sedimentation patterns of ferritins, however, were shown to be dependent on the concentration of the protein; as the concentration decreased the protein appeared to sediment at lower densities. Thus, at the low concentration levels usually used for analysis of serum ferritin, tissue ferritins also sedimented in the same lower density regions. Iron labeling experiments indicated that the sedimentation changes upon dilution were not due to release of iron or was there any indication that the protein dissociated into subunits. The anomalous sedimentation behavior of serum ferritin should therefore not be interpreted in terms of its iron content. The disclosure that serum ferritins may have full complements of iron is counter to the prevalent view that serum ferritins are low iron forms and has potential implications with regard to the sources and possible function of this protein in the circulation.

Animals↗
PubMed1985

Isolation and characterization of a colonic autoantigen specifically recognized by colon tissue-bound immunoglobulin G from idiopathic ulcerative colitis.

Patients with idiopathic ulcerative colitis (UC) have a colonbound antibody (CCA-IgG) that reacts with colon tissue extracts. We have partially characterized a colonic protein that is specifically recognized by CCA-IgG. CCA-IgG was eluted from operative colon specimens from 10 patients with UC. A colon tissue-bound IgG was similarly eluted from six patients with Crohn's colitis, two with ischemic colitis, and one with diverticulitis. Purified serum IgG from patients with Crohn's disease, from normal subjects and a patient with myeloma were also used as additional controls. For detection of antigen(s), tissue extracts were prepared from 26 specimens of colon (UC, 12; Crohn's disease, 6; normal, 4; other controls, 4), 8 specimens of human normal stomach, duodenum, ileum, and liver (2 each). Tissue extracts were also prepared from rats and mice, including germ-free rat colons and rat's fetal colons. Immunorecognition of CCA-IgG to the tissue extracts was examined by affinity-column chromatography and by transblot analysis. Tissue-extracted proteins were electrophoresed in SDS-polyacrylamide gel, transferred to nitrocellulose sheet, and probed with iodinated CCA-IgG, colonic IgG from other inflammatory bowel disease patients, UC serum IgG, and control serum IgG. Although many proteins were present in colon tissue extracts, 9 of 10 CCA-IgG consistently recognized a protein of 40 kD. None of the nine IgG preparations from colon specimens of patients with Crohn's colitis and other colonic inflammatory diseases reacted with the 40-kD protein. Five of six symptomatic UC serum IgG and none of eight control serum IgG reacted with the 40-kD protein. The 40-kD protein was present in all colon specimens and it appeared to be organ specific. It was absent in mouse and rat tissues, including colon. The 40-kD protein is not actin and nor a part of the Ig molecule. These results suggest that the 40-kD protein is a colonic "autoantigen" that may initiate a specific IgG antibody response in UC.

Autoantigens↗