Search PubMed⌕ Search

Biomedical subjects

G Takahashi

Publications and source records attributed to G Takahashi.

At least 19 recordsLinked to original sources
PubMed1999

[Short-term fluctuation of blue-on-yellow perimetry in normal eyes].

PURPOSE: To evaluate short term fluctuation (SF) of blue-on-yellow perimetry (B/Y) as compared with white-on-white perimetry (W/W) in normal eyes. SUBJECTS AND METHOD: One eye each of 25 healthy persons underwent B/Y and W/W perimetry repeated 5 times each. The test subjects had no previous experience of perimetry. An automated perimeter, Humphrey Field Analyzer, model 750, was used throughout. RESULTS: The SF at the first session of B/Y perimetry averaged 2.02 dB. This value was significantly different from those of the subsequent 4 sessions. Each of SF of B/Y perimetry at the first two sessions was significantly different from that of W/W perimetry at the first two sessions. The SF of B/Y perimetry showed wider fluctuations than those of W/W perimetry at each session. CONCLUSION: B/Y perimetry in normal eyes showed individual differences as well as fluctuations between the initial and consecutive sessions. This feature has to be considered in interpretation of the findings.

Adolescent↗
PubMed1998

Acquired undescended testis.

We report an unusual case of a 22-year-old man who presented with the left testis spontaneously ascended to a non-scrotal position. The testis had been documented to be intrascrotal without any sign of up-migration when the man was 12 years old. On surgery, the cryptorchid testis was found to be located within the superficial inguinal pouch. The testis was atrophic with the spermatic cord too short. On dissection, a remnant string of the closed processus vaginalis was observed within the cord, and the distal end of the gubernaculum was abnormally attached to the fascia near inguinoscrotal junction. Histopathologic findings of the testis were that of the Sertoli-cell-only syndrome which may represent the end-stage of germinal cell hypoplasia, a pathologic sequela common in postpubertal undescended testis. We recommend 3 diagnostic criteria for the acquired undescended testis and emphasize that testicular descent should be confirmed in infancy and re-confirmed periodically through puberty by the health care physician. Our observations seem to support the theory that acquired undescended testis may be caused by a postnatal failure of the spermatic cord to elongate in proportion to somatic growth.

Adult↗
PubMed1996

Selective growth of human mast cells induced by Steel factor, IL-6, and prostaglandin E2 from cord blood mononuclear cells.

To establish the method for generating a large number of mature human mast cells, we cultured cord blood mononuclear cells (CBMC) in several conditions in the presence of Steel factor (SF). Among several cytokines tested, IL-6 enhanced SF-dependent mast cell growth from purified CD34+ cells for more than 8 wk in culture. When CBMC were cultured instead of CD34+ cells, IL-6 enhanced the mast cell development in the presence but not in the absence of PGE2. PGE2 enhanced the SF- and IL-6-dependent development of mast cells from CBMC probably by blocking granulocyte-macrophage CSF (GM-CSF) secretion from accessory cells, because 1) PGE2, or anti-GM-CSF enhanced the mast cell development induced by SF and IL-6 from CBMC, but not from CD34+ cells; 2) GM-CSF inhibited the enhancing effect of IL-6 on the mast cell development from CD34+ cells; and 3) PGE2 inhibited GM-CSF secretion from CBMC. The mast cells cultured in the presence of SF, IL-6, and PGE2 for >10 wk were 99% pure, and seemed to be functionally mature, because 1) they contained 5.62 micrograms of histamine and 3.46 micrograms of tryptase per 10(6) cells; and 2) when sensitized with human IgE and then challenged with anti-human IgE, the cells released a variety of mediators such as histamine, and an increase in intracellular Ca2+ was found in advance of the activation of membrane movement by using a confocal laser-scanning microscope. Electron-microscopic analysis revealed that some of the cultured mast cells are morphologically mature since they filled with scroll granules and contained crystal granules.

Base Sequence↗
PubMed1996

Bryostatin 1 acts synergistically with interleukin-1 alpha to induce secretion of G-CSF and other cytokines from marrow stromal cells.

The protein kinase C (PKC) activator bryostatin 1 (bryo) has substantial antileukemic and hematopoietic actions. Bryo promotes the in vitro growth of normal hematopoietic progenitors by inducing the release of growth factors from accessory cells. We have examined the effects of bryo on the expression and release of certain myeloid growth factors from fibroblastlike marrow stromal cells (MSC). Substantial release of granulocyte colony-stimulating factor (G-CSF), granulocyte-macrophage colony-stimulating factor (GM-CSF). or interleukin-6 (IL-6) following bryo treatment was seen only in MSC cultures contaminated with macrophages. Bryo alone was ineffective in inducing release of the cytokines from MSC cultures containing only fibroblastlike stromal cells. When MSC were treated with IL-1alpha, substantial quantities of the cytokines (G-CSF, GM-CSF,IL-6) were released. Bryo acted synergistically with IL-1 alpha to significantly increase cytokine release to- to nine-fold compared to IL-1alpha alone (p < 0.016). Neither Il-1alpha nor bryo, alone or in combination, induced release of stem cell factor (scf) from MSC. The synergistic interaction between IL-1alpha and bryo was dose- and schedule-dependent, requiring simultaneous application of IL-1alpha and bryo for optimum effect. Bryo alone induced no G-CSF mRNA accumulation but increased the level seen with IL-1alpha treatment by 50%. The synergistic interaction of bryo and IL-1alpha required PKC, since it was antagonized by agents which depleted or inhibited PKC but not by a protein kinase A antagonist. The increase in G-CSF mRNA was associated with a marked increase in mRNA stability. Bryostatin may promote the release of cytokines from several accessory cell populations, including MSC, to accomplish its in vivo hematopoietic effects.

Bone Marrow↗
PubMed1995

Longitudinal assessment of physiological and psychophysical measures in cochlear implant users.

OBJECTIVE: The purpose of this study was to evaluate the effects of long-term electrical stimulation on human cochlear implant users. DESIGN: Repeated measures of electrically evoked auditory brain steam response (EABR) threshold, slope of the EABR growth function, and behavioral measures of threshold and dynamic range were made for a group of 22 Ineraid cochlear implant users and 19 Nucleus cochlear implant users over a 3- to 5-yr period. RESULTS: Data from both Ineraid and Nucleus cochlear implant users suggest that EABR threshold, slope of the EABR growth function, and behavioral measures of threshold and dynamic range remain reasonably stable for periods up to 5 yr postimplant. CONCLUSIONS: The results of this study show little evidence that prolonged electrical stimulation through daily use of a cochlear implant has deleterious effects on the auditory system.

Cochlear Implants↗
PubMed1993

Differences between adrenomedullary adrenaline and noradrenaline cells: quantitative electron-microscopic evaluation of their differential cellular association with supporting cells.

Quantitative differences in cellular association of adrenomedullary chromaffin cells with other types of cells, mainly supporting cells, were studied. Adrenaline (A) and noradrenaline (NA) cells were compared. Electron micrographs (12000 x) of profiles of A and NA cells, bordering against other types of cells, were used for quantitative evaluation. Supporting cells constituted the majority of the non-chromaffin cell types. Occurrence frequencies of chromaffin cells contiguous with other types of cells were: (1) higher for A cells (68.9%, 199/289) than for NA cells (11.0%, 34/309) in case of small contact regions (chi 2-test: P < 0.001), and (2) higher for NA cells (68.3%, 211/309) than for A cells (9.7%, 28/289) in case of extended contact regions (P < 0.001). In conclusion, the extent of cellular association with supporting cells was remarkably lower in A cells than in NA cells. Such an arrangement is likely to be appropriate for the extensive, homogeneous control and amplified response characteristic of A cells, and for the close range, complex control and more diverse responses characteristic of NA cells.

Adrenal Medulla↗
PubMed1992

Rough endoplasmic reticulum in the adrenaline and noradrenaline cells of the adrenal medulla: effects of intracranial surgery and pinealectomy.

UNLABELLED: Adrenal medullas in 53-day-old rats of the nonoperated (NO) group (n = 31), the sham-operated (SPX) group (n = 35) and the pinealectomized (PX) group (n = 38) were examined electron microscopically 14 days after surgery. Cell profiles showing solitarily and sparsely distributed rough endoplasmic reticulum (RER) were most frequent in the PX group (daily mean: 66.9%, 427/638), less in the NO (56.0%, 336/600), and least in the SPX (48.5%, 297/612) in adrenaline (A) cells (chi 2-test: P less than 0.001), while most frequent in the NO group (68.8%, 340/494), less in the PX (64.3%, 303/471), and least in the SPX (57.4%, 256/446) (P less than 0.005) in noradrenaline (N) cells. Individual variation was less in A cells than in N cells. Cell profiles showing a large accumulation of RER was more frequent in A cells (NO:8.5%, SPX:13.1%, PX:7.7%) than in N cells (NO:2.8%, SPX:4.5%, PX:4.7%) (controls: P less than 0.001). Sham pinealectomy increased a large accumulation of RER in A cells (P less than 0.02) and a small aggregation of RER in N cells (P less than 0.005) with opposite effects of pinealectomy (P less than 0.005, P less than 0.025). Pinealectomy decreased a small aggregation of RER without effects of sham pinealectomy in A cells (P less than 0.001). CONCLUSIONS: (1) Accumulation or aggregation of RER in adrenomedullary chromaffin cells was influenced from the pineal gland either as or without effects of intracranial surgery, and (2) RER in adrenomedullary chromaffin cells showed differences due to cell types.

Adrenal Medulla↗
PubMed1992

Effect of methylxanthine derivatives on T cell activation.

In a Phase I-II trial examining the effect of prophylactic administration of pentoxifylline (PTX) on bone marrow transplant-associated morbidity, there was an apparent reduction in the incidence and severity of acute graft-versus-host disease. To determine if PTX might be directly immunosuppressive, its effects on T cell activation and proliferation were examined. PTX and several cogeners were found to directly suppress T cell proliferation in response to phytohemagglutinin, to allogeneic cells in a mixed leukocyte reaction, and to cross-linking the CD3 complex. The effects were dose-related and associated with suppression of secretion of tumor necrosis factor-alpha (TNF alpha). However, the inhibition of proliferation was not solely due to this effect since adding excess recombinant TNF alpha did not restore the proliferative response. These data suggest that PTX may be clinically useful in suppressing allogeneic reactions in bone marrow transplantation.

Antigens, Differentiation, T-Lymphocyte↗
PubMed1992

[Auto recording system for the Goldmann perimeter].

In order to develop a method for converting the Goldmann perimeter data directly for computer storage and evaluation, a recording instrument was designed as a modification of the Goldmann perimeter. By installing the two potentiometers on the pantographic arm and electrical switches, the position of the test target and the setting of the four levers which defines the size and the brightness of the test target were transferred directly to the computer. Accuracy of this recording system is better than 1.3 degree over the entire surface of the chart. This system will make it possible to easily follow changes in the visual fields of the same patient, i.e. shape change, numerical value.

Humans↗
PubMed1992

[Surgery versus detachable balloon embolization of pulmonary arteriovenous fistula: clinical experience].

We experienced 4 pulmonary arteriovenous fistula cases 2 of which were treated surgically and 2 were subjected to detachable balloon embolization therapy. Favorable results were obtained in the detachable balloon embolization therapy. In treating pulmonary arteriovenous fistula, if the lesion is in the position where the catheter can be reached easily and is composed of a single afferent-efferent vessel unit, it would be advisable to perform the embolization therapy first, and then to apply an operative procedure preserving lung tissue as much as possible.

Adult↗
PubMed1991

Intratesticular leiomyoma: a case report.

A case of leiomyoma of the testis is reported. The origin of the intratesticular leiomyoma is controversial, but recently it is thought to arise from the contractile cells in the tunica propria of the seminiferous tubules. This is the first case reported in Japan and the fifth in the world literature.

Adult↗
PubMed1988

[The surgical treatment of hypospadias and related problems].

Of 33 patients with hypospadias operated on consecutively by a single surgeon between 1977 and 1986, 27 had undergone a 2-stage Belt-Fuqua procedure and 6 were repaired using several types of a one-stage method. The over-all success rate was 64%. Meanwhile, a fistula developed in 6 patients, meatal stenosis in 3; the over-all complication rate was 36%. A comparative review of late complications is presented. Efforts should be made to achieve excellent functional as well as cosmetic results.

Adolescent↗
PubMed1987

[Vaginal polyp in an infant girl].

A case of vaginal polyp in an infant girl was presented. The tumor was polypoid shape and yellow so that it resembled sarcoma botryoides. Histopathological findings showed hamartomatous appearance with hemangiomatous portions in the stroma. For 5 years after simple resection, she has been well without recurrence.

Female↗
PubMed1987

[A case of blind-ending bifid ureter].

A case of blind-ending bifid ureter in a 6-year-old girl is presented. Excretory urography revealed a right blind-ending ureter which was resected surgically. Besides this, she had megaureters on both sides, and uretero-vesiconeostomy was undertaken. Although urinary tract infection had continued for several months, she had no episode of fever after operation.

Child↗