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Biomedical subjects

Y Taguchi

Publications and source records attributed to Y Taguchi.

At least 325 records · Page 18Linked to original sources

Comparison of histidine decarboxylases from rat stomach and brain with that from whole bodies of rat fetus.

Histidine decarboxylases from the stomach and brain of adult rats were purified 380- and 160-fold, respectively, and their properties compared with those of the enzyme from whole bodies of fetal rats (7600-fold purification). The molecular weights (about 90,000) and the apparent Km values for L-histidine (3 X 10(-4) M) of the three enzymes were similar. The pI value of the fetal enzyme was 5.0, and that of the brain enzyme was 5.4. Histidine decarboxylase of the stomach showed two peaks of activity corresponding to those of the fetal and brain enzymes (pI's of 5.0 and 5.4) on isoelectric focusing. Anti-fetal-histidine decarboxylase antiserum inhibited the stomach and fetal enzymes extensively, but the brain enzyme only slightly. These results indicate that there are at least two types of histidine decarboxylase in rat tissue.

Animals↗

Immunohistochemical evidence for the coexistence of histidine decarboxylase-like and glutamate decarboxylase-like immunoreactivities in nerve cells of the magnocellular nucleus of the posterior hypothalamus of rats.

Immunohistochemical staining of alternate consecutive sections revealed numerous histidine decarboxylase (L-histidine carboxy-lyase, EC 4.1.1.22)-like immunoreactive neurons that also contained glutamate decarboxylase (L-glutamate 1-carboxy-lyase, EC 4.1.1.15)-like immunoreactive structures in the tuberal magnocellular nucleus, the caudal magnocellular nucleus, and the postmammillary caudal magnocellular nucleus of the posterior hypothalamus of rats. Furthermore, in immunohistochemical double-staining procedures, almost all neurons in the magnocellular nuclei had both histidine decarboxylase-like and glutamate decarboxylase-like immunoreactivities. These results suggest the coexistence of histamine and gamma-aminobutyric acid in single neurons in these nuclei.

Animals↗

Autoregulation of cortical blood flow and oxygen tension in the rabbit.

The relationship between cerebral blood flow autoregulation and oxygen tension of cerebral tissue is not fully known. We have examined the autoregulation of local cortical blood flow (CoBF) and cortical oxygen tension (bPO2) in the rabbit. CoBF was measured continuously by using the heated thermocouple technique and bPo2 was monitored by the polarographic method. Intravenous injection of phenylephrine hydrochloride or trimethaphan camsylate was used to test for autoregulation by increasing or decreasing perfusion pressure. The mean values of CoBF and bPO2 were 36 +/- 5 ml/100g/min and 32 +/- 12 mmHg respectively at 90 mmHg mean arterial blood pressure (MABP). The changes in both CoBF and bPO2 with changing perfusion pressure were often relatively small at near baseline blood pressure and became more pronounced with large increases or decreases in MAPB. On returning from high MABP to baseline blood pressure, a hysteresis effect on CoBF was observed in 20 out of 22 cases. The autoregulation of CoBF was maintained in the range between 80 and 100 mmHg MABP. On the other hand, bPO2 was maintained constant in the range between 75 and 110 mmHg. This range is significantly wider than that of CoBF. We conclude that autoregulation of CoBF limits changes in local CoBF to maintain constant oxygen tension in brain tissue.

Animals↗

Serum somatomedin A in Perthes' disease.

Serum somatomedin A, determined by radioreceptor assay in 47 children with Perthes' disease, was significantly reduced as compared to normal children of the same age. Nine children underwent the 1-Dopa tolerance tests to evoke growth hormone release; a normal response was found in eight. Patients with Perthes' disease tend to be short in stature with "disproportionate skeletal growth" of the limbs; growth is less in the distal than in the proximal extremities. The low serum levels of somatomedin A suggest some growth disturbance during the development of Perthes' disease.

Adolescent↗

Electron microscopic identification of histidine decarboxylase-containing endocrine cells of the rat gastric mucosa. An immunohistochemical analysis.

The localization of histidine decarboxylase-like immunoreactive structures in the mucosal cells of the rat stomach was studied by the peroxidase-antiperoxidase method. At the light microscopic level, histidine decarboxylase-like immunoreactivity-containing cells were concentrated in the basal part of the oxyntic region, whereas in other areas no immunoreactive cells were seen. Ultrastructural study showed that reaction end products were diffusely distributed within the cytoplasm of the enterochromaffinlike cells but other cell types such as A cells, G cells, and enterochromaffin cells were not labeled. These findings suggest that enterochromaffinlike cells synthesize histamine.

Animals↗

[Case of aneurysmal bone cyst of the skull].

A case of aneurysmal bone cyst of the right temporal bone was reported. The patient was a 36-year-old male who was admitted to our hospital with complaints of decreased right hearing and transient impairment of the right vision. A large tumor was palpated on the right temporal bone. Neurological examinations revealed right auditory loss, along with right facial weakness of peripheral type, and minimal pyramidal signs on the right side. The results of the laboratory examination proved to be normal. Neuroradiological examinations tended to be quite impressive. Plain x-ray films of the skull showed a blow out appearance of the right temporal bone and a bone decay in the right middle fossa, the right anterior clinoid process, and the posterior half of the right zygomatic arch. Angiograms revealed a right temporal extradural mass lesion without vascularity. CT scans showed a moderately enhanced mass lesion of soap bubble appearance in the right middle fossa. Surgical treatment was done under the diagnosis of extradural bone tumor. The operative findings disclosed many cysts containing bloody fluid and xanthochromic fluid. Numerous multinucleated giant cells, spindle cells, and foam cells were found in the microscopic examination. On the basis of macroscopic and microscopic findings, the patient was diagnosed as having an aneurysmal bone cyst. The aneurysmal bone cyst of the skull is very rare and sixteen cases have been reported in detail. This case had two interesting points, one was the transient impairment of visual acuity and the other was the CT findings.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

[Distribution of ethanolamine oleate after injection in esophageal varices].

The purpose of this study is to know the systemic distribution of sclerosant injected into esophageal varices. Sclerotherapy for esophageal varices was performed for 14 times in 11 patients. The patients were divided into two groups according to the content of sclerosant. Seven patients received a total of 9 intravariceal injections (IVI) with 7 to 30ml of 5% ethanolamine oleate (EO) which contained meglumine diatrizoate (Angiographin) and four patients received a total of 5 IVI with 10 to 20ml of 4.5% EO which contained a 10% volume of 99mTcO-4 solution (EO-99mTc). Distribution of injected materials was observed by X-ray fluoroscopy in the former group and by a scintillation camera in the latter. In both methods most of the sclerosant disappeared from the injected site within five minutes leaving a trace in the varices. Then, the sclerosant was disseminated throughout the body via portal vein. When more than 20ml of sclerosant was injected, some flowed into the azygos vin through the periesophageal vin. After IVI the varices showed atrophic changes, though the sclerosant did not stay in the varices.

Adult↗

Reversal of transplant rejection by monoclonal antiblast antibody.

The first clinical trial of an antiblast monoclonal antibody, CBL1, in the treatment of kidney allograft rejection is described. The theory that this antibody might destroy active clones of cells without major side effects was given validity by a previously described study showing prolongation of skin allograft survival in rhesus monkeys. CBL1 was used to treat kidney allograft rejections in 11 patients with a one-haplotype-identical related-donor graft who had been prestimulated with donor-specific transfusions and 8 patients with cadaver grafts who had been prestimulated with multiple transfusions. 15 of the rejections were steroid-resistant. Although CBL1 had no effect on the peripheral blood lymphocyte counts, rejections were reversed in 17 of 19 patients. There was 1 graft loss in the 11 recipients of related-donor grafts and 3 in patients with cadaver-donor grafts. Side effects associated with administration of antilymphocyte serum--ie, chills, fever, and thrombocytopenia--did not develop in any of the patients treated with CBL1. It is postulated that administration of an antiblast monoclonal antibody during rejection of a kidney kills only those cells that are reacting against the graft. This could result in the maintenance of normal lymphocyte numbers and immunological functions against other antigens.

Antibodies, Monoclonal↗

Evidence for the presence of a histaminergic neuron system in the rat brain: an immunohistochemical analysis.

Histamine-containing cells in rats were identified by indirect immunofluorescent histochemistry using an antibody raised against histidine decarboxylase (HDC), the enzyme forming histamine, which was purified from fetal rat liver. HDC-like immunoreactive (HDCI) structures could be detected in the brain as well as in peritoneal mast cells and basal-granulated cells in deep crypts of the gastric mucosa of rats. Numerous HDCI neurons were found in the posterior hypothalamic area and HDCI nerve fibers with a varicose appearance of fluorescence were widely distributed in various regions of the brain.

Animals↗

Method for enzymatic determination of imidazole acetic acid.

A method for enzymatic assay of imidazole acetic acid (ImAA) was developed, based on the strict substrate specificity of imidazole acetate monooxygenase from Pseudomonas sp. [Maki et al. (1969) J. Biol. Chem., 244., 2942-2950], which catalyzes concomitant conversion of NADH to NAD+. Thus, ImAA was determined by measuring decrease in absorbancy at 340 nm. Tissue extracts were partially purified and/or concentrated by column chromatography on Bio-Rad AG-1 before enzymatic assay. The lowest measurable level of ImAA by this method was 2 nmol.

Animals↗

Monitoring of B lymphocyte response with the protein-A plaque assay in kidney transplant patients.

The protein-A plaque assay was used for serial monitoring of spontaneous plaque-forming lymphocytes (PFC) in blood or thoracic duct lymph of 30 renal transplant patients. In patients experiencing early or delayed graft rejection, PFC manifested a 10-fold increase over the preoperative or control level within one month of the transplantation. Patients accepting the renal graft did not exhibit a remarkable PFC response. Among the factors examined (proportion of B cells, donor source, acute tubular necrosis, intraoperative blood transfusion, antilymphocyte serum, histocompatibility, and rejection), the PFC response was most closely related to graft rejection. Changes in serum immunoglobulin (Ig) did not appear to correlate with the PFC response. By using Ig-class-specific antisera, secreted Ig was identified as IgG, IgM, and IgA. This may indicate that renal grafts induce polyclonal activation of the recipient's B cells.

B-Lymphocytes↗

Effect of alpha-fluoromethylhistidine on the histamine content of the brain of W/Wv mice devoid of mast cells: turnover of brain histamine.

In the brains of W/Wv mutant mice that have no mast cells, the histidine decarboxylase (HDC) level is as high as in the brain of congenic normal mice (+/+), but the histamine content is 53% of that of +/+ mice. The effects of alpha-fluoromethylhistidine (alpha-FMH) on the HDC activity and histamine content of the brain of W/Wv and +/+ mice were examined. In both strains, 30 min after i.p. injection of alpha-FMH the HDC activity of the brain had decreased to 10% of that in untreated mice. The histamine content decreased more gradually, and after 6 h about half of the control level remained in +/+ mice, whereas histamine had disappeared almost completely in W/Wv mice. It is concluded that the portion of the histamine content that was depleted by HDC inhibitor in a short time is derived from non-mast cells, probably neural cells. The half-life of histamine in the brain of W/Wv mice was estimated from the time-dependent decrease in the histamine content of the brain after administration of alpha-FMH: 48 min in the forebrain, 103 min in the midbrain, and 66 min in the hindbrain.

Animals↗