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S Toda

Publications and source records attributed to S Toda.

At least 91 records · Page 5Linked to original sources
PubMed1997

Effects of sex hormones on the metabolism of tryptophan to niacin and to serotonin in male rats.

It is known that deaths attributable to pellagra, which is considered to be a disease caused by the disturbance of tryptophan metabolism, have been approximately two-fold higher in women than in men. We investigated the effects of the administration of female and male sex hormones on the contents of tryptophan and such metabolites as serotonin, nicotinamide, N1-methylnicotinamide, N1-methyl-2-pyridone-5-carboxamide, and N1-methyl-4-pyridone-3-carboxamide, and on the conversion ratio of tryptophan to niacin in male rats. Feeding a diet containing estrone or testosterone had no effect on the concentrations of tryptophan and serotonin in the blood and brain, or on the concentration of 5-hydroxyindole-3-acetic acid in the brain. On the contrary, feeding a diet containing estrone caused to a decrease in the urinary excretion of nicotinamide, N1-methylnicotinamide, N1-methyl-2-pyridone-5-carboxamide, and N1-methyl-4-pyridone-3-carboxamide, and of the conversion ratio of tryptophan to niacin when compared with the control rats. Feeding a diet containing testosterone had no effect on any parameter. We postulate from these findings that the cause of higher pellagra deaths in women than in men is attributable to the decrease in the formation of niacin from tryptophan, but not in the formation of serotonin by the female hormone. It seems likely that female sex hormones inhibit the synthesis of niacin from tryptophan, and that women, especially during pregnancy, will be more at risk to pellagra than are men.

Animals↗
PubMed1997

[Clinicopathological studies of craniocerebral gunshot injuries].

UNLABELLED: Gunshot wounds are rare in Japan because of few regulatory laws against the possession of guns. Nevertheless such wounds are increasing in prevalence these days. Reports on the microscopic findings concerning these intracerebral lesions are fewer than those on the macroscopic findings in the scalp, the skull and the intracranial cavity. In this study we evaluated computed tomographical and histopathological findings in craniocerebral gunshot injuries. CASES: Nine patients with gunshot wounds to the head were presented. All were male and the age ranged from 17 to 66 years. Four were suicides and four were attempted murders and the last one was of unknown etiology. Morphological examination was performed on 5 autopsy cases. The distance of the bullet from the cranial cavity was as follows: long distance, 4 cases; close contiguity, 5 cases. The calibers of the weapons were as follows: 38 mm in 6 cases, 45 mm in 1 case and unknown in 2 cases. RESULTS: CT scans were examined in six cases, which revealed a missile track, hemorrhagic contusion, traumatic subarachnoid hemorrhage and marked tension pneumocephalus. In some cases, CT scan also revealed bony and metallic fragments, some deep within the cranial cavity. In the histopathological study, we found marked swollen brain (brain weight over 1500 mg) and hemorrhagic contusion in the vicinity of the missile track and interhemispheric fissure, and widespread traumatic subarachnoid hemorrhage and intraventricular hematoma. We would like to emphasize especially the remote contusion seen in the distant part of the missile track as well as massive exsudation and hemorrhage around the nerve fiber bundles. Remote contusion was observed in the inferior surface of the fronto-temporal lobes, and bilateral hemorrhagic contusion was seen in the vicinity of the superior longitudinal fissure on CT scans and autopsy findings. In one case, the bullet rotated within the intracranial cavity. In conclusion, nine cases of craniocerebral gunshot injuries were examined, while we also reviewed the medical literature concerning the shearing injury produced by gunshot brain wounds. The head injuries were further delineated by the correlation between autopsy and computerized tomography findings.

Adolescent↗
PubMed1997

[Retinitis pigmentosa and color vision deficiency in Kamigoto island, Nagasaki Prefecture].

I studied two genetic diseases, retinitis pigmentosa (RP) and color vision anomaly, in Kamigoto, one of the off-shore islands in Nagasaki Prefecture. The Prevalance of RP patients in this island was estimated to be one in 473 persons. Among the RP patients observed, familial cases whose disorders are transmitted through successive generations comprised 25.7%. Although it seems that the inheritance mode of RP in these familial cases is autosomal dominant, an autosomal recessive fashion showing quasi-dominance cannot be ruled out, because inbreeding frequently occurs on this island. There were at least two types of RP, one with late onset (40 years of age or later) and the other with early onset, and patients with the latter RP tended to have a poor prognosis. Only a few RP patients had posterior subcapsular cataract, and none had pseudexfoliation in spite of advanced age. Color vision anomalies were found in 3.86% of high-school boys and in 0.41% of girls in this island, and they included protanopia (4.2%), protanomaly (10.4%), deuteranopia (37.5%), and deuteranomaly (47.9%). The prevalence in boys was comparable to that in the general Japanese population, but the prevalence in girls was higher in Kamigoto than in other districts. It is most likely that the unique findings regarding the two disorders reflect geographical and/or social features in Kamigoto island.

Adolescent↗
PubMed1996

Pathology of malignant melanoma.

This article describes the histopathologic and clinical appearance of benign simulators of melanoma, radial and vertical growth phase malignant melanoma, and unusual variants of melanoma. Microstaging and prognostic parameters also are discussed.

Humans↗
PubMed1996

Glycation decreases the stability of the triple-helical strands of fibrous collagen against proteolytic degradation by pepsin in a specific temperature range.

When fibrous collagen of rat tail tendons was glycated by incubation with ribose, it became highly insoluble in dilute acetic acid and resistant to pepsin digestion at 5 degrees C, since it was cross-linked by advanced glycation end products. Extensively glycated fibrous collagen was found to be much less stable than non-glycated control fibrous collagen against pepsin digestion at 30 degrees C. Under conditions where nearly all of the glycated fibrous collagen was degraded into small peptides by pepsin, approximately 45% of the control collagen was left as large polypeptides having nearly the whole length of its triple-helical region. A soluble collagen, which consisted primarily of the triple-helical region of monomeric collagen, was found to be glycated as efficiently as the fibrous collagen on incubation with ribose at 30 degrees C, while the rate of cross-linking of the soluble collagen was very low, suggesting that the triple-helical strands do not undergo intramolecular cross-linking and that most of the cross-links produced in the glycated fibrous collagen are intermolecular ones. The glycated soluble collagen was as stable as the control collagen against pepsin digestion at 30 degrees C. These results indicate that the triple-helical strands of glycated fibrous collagen are much less stable than those of the non-glycated form against proteolytic digestion by pepsin at a temperature close to but below their melting point. Sugar-derived intermolecular cross-links are supposed to underly the decreased stability of the triple-helical strands.

Acetic Acid↗
PubMed1996

[Surgical treatment for ascending aortic aneurysm using a transthoracic left ventricular venting].

Three patients with ascending aortic aneurysms underwent graft replacement using deep hypothermic circulatory arrest with continuous retrograde cerebral perfusion. In all three cases, preoperative radiographic examination revealed that the aneurysm was large, thin, and adherent to the back of the sternum. For this reason, left ventricular venting was performed through a left thoracotomy before median sternotomy, to decrease both the risk of rupture of the aneurysm and the difficulty of cannulation. This new method, called transthoracic left ventricular venting, was very useful for performing a median sternotomy under hypotensive and hypothermic conditions adequate to reduce the risk of rupture and to manage any rupture immediately through deep hypothermic circulatory arrest.

Aged↗
PubMed1996

[Clinical problems in surgical treatment for active infective endocarditis].

From October, 1982, to December, 1995, 22 patients with active infective endocarditis underwent surgical treatment. Of 22 patients, 12 patients (group P) demonstrated microorganisms on blood culture obtained at the operation and/or in the excised valve, and 10 patients (group N) showed acute inflammatory reaction in the excised valve microscopically. Operative mortality in group P was significantly higher than that in group N (50% versus 0%,p < 0.01). Especially in group P, five of six patients (83%) with uncontorolled infection for more than eight days died within 30 days of operation. This showed that prolonged preoperative periods of uncontrolled infection influenced the surgical outcome of active infective endocarditis. In conclusion, patients who do not promptly response to antibiotic treatment must be considered for early operation within seven days of the diagnosis of infective endocarditis to decrease operative mortality. The plasma level of CRP and definition of sepsis may be useful as indicators of uncontrolled infection.

Adult↗
PubMed1996

[Tuberculous mediastinal lymphadenitis presenting as hoarseness].

A 70 year-old woman was admitted to our hospital complaining of hoarseness. Bronchoscopic examination revealed that the left vocal cord was fixed in the paramedian position, and therefore left recurrent nerve paralysis was suspected. Although a chest X-ray film showed no abnormal findings, a chest computed tomogram showed that pretracheal (#3) and subaortic (#5) lymph nodes were swollen (1 to 2 cm in diameter). An open biopsy was done. Histological examination of the resected mediastinal lymph nodes revealed an accumulation of Langhans giant cells and epithelioid cells in caseous necrosis. An acid-fast bacillus was seen after Ziehl-Neelsen staining. This was a rare case of mediastinal tuberculous lymphadenitis in which hoarseness was useful for early diagnosis. Fifty-three cases of tuberculous mediastinal lymphadenitis have been reported in Japan.

Aged↗
PubMed1995

Mononuclear cell thyroiditis in rats with graft-versus-host disease.

Rats with graft-versus-host disease (GVHD), induced by injecting spleen cells of parental strain rats (Brown Norway) into non-irradiated (Brown Norway x Lewis) F1 hybrid rats, develop thyroiditis. This is characterized by mononuclear cell infiltration with destruction of the epithelium and a significant reduction in serum thyroid hormone levels. Immunohistochemically, the mononuclear cells consisted mainly of CD8-positive cells and macrophages. These findings provide evidence that the thyroid gland can now be enumerated as one of the target organs during GVHD. The CD8-positive cells may serve as important effector cells in lesion development, either by direct cytotoxicity or by supporting the cytotoxic potential of macrophages.

Animals↗
PubMed1995

The mechanism of interaction of sodium dodecyl sulfate with elastic fibers.

Sodium dodecyl sulfate (SDS), an anionic hydrophobic ligand, is known to alter the mechanical properties of elastic fibers. In order to analyze the mechanism of the alteration, two forms of fibrous elastins, "solid" and "powder" elastins, which consisted of fascicular elastic fibers and single or oligomeric elastic fibers, respectively, were prepared from bovine aorta, and the interactions of SDS with these elastins in the presence and absence of 0.15 M NaCl were studied. The solid elastin was able to retain 1.2- to 1.4-fold larger amounts of SDS than the powder elastin under both conditions, and both elastins retained 1.2-fold or larger amounts of SDS in the presence of NaCl than in its absence. Whereas both elastins released the retained SDS gradually on repeated washing with an SDS-free buffer, the release rates from the solid elastin, especially the rate in the presence of NaCl, were much smaller than those from the powder elastin, and the solid elastin retained approximately 40% of the bound SDS under conditions where the powder elastin lost most of its SDS. The SDS-binding capacities of both elastins were significantly lower than those of soluble kappa-elastin and serum albumin, which bound SDS homogeneously on the polypeptide chains. When the washed SDS-bound solid elastin was incubated with methylene blue and examined under a microscope, most of the methylene blue-SDS complex was located at the interfiber spaces of the elastic fibers. These results suggest that SDS alters the mechanical properties of elastic fibers by binding to the interfiber spaces and surfaces of the fibers rather than by binding to the internal polypeptide chains.

Animals↗
PubMed1995

Biochemical characterization of the fibres of collagen and elastin in the aortic wall of SHRSP.

1. Vessel wall fragments consisting of collagen, elastin and other insoluble proteins were prepared from the aortas of 6 month old WKY and SHRSP and dead, elderly humans. 2. Prolonged incubations of these fragments with pepsin below or at 30 degrees C resulted in different amounts of insoluble materials containing similar or larger proportions of collagen and other insoluble proteins than the respective vessel fragments. The amounts of the pepsin-insoluble materials obtained from SHRSP were larger than those from WKY but were much smaller than those from elderly humans. 3. The elastins isolated from the vessel fragments were solubilized by pepsin much more effectively than the respective vessel fragments. 4. The pepsin-insoluble materials from WKY were composed of thin mesh-shaped materials, while these materials from both rats did not contain a significant number of distinctive fibrils of collagen, the materials from elderly humans did contain numerous distinctive fibrils of collagen. 5. Large fractions of both the collagen and other proteins in the pepsin-insoluble materials were solubilized by incubation with a crude bacterial collagenase below 30 degrees C or by incubation with pepsin above 40 degrees C where the triple-helical regions of the collagens were unfolded. 6. These results appear to indicate that the aortic wall of SHRSP contains larger amounts of some insoluble components that immobilize the collagen fibrils than that of WKY, but the aortic walls of elderly humans contain much larger amounts of these components than that of SHRSP.

Aged↗
PubMed1995

Effects of various types of extracellular matrices on adhesion, proliferation, differentiation, and c-fos protein expression of porcine thyroid follicle cells.

Thyroid follicles in vivo are embedded in extracellular matrix (ECM). The composing epithelial cells are in close contact with ECM at the basal side. To examine cell-to-ECM interactions, we studied adhesion, proliferation and differentiation of porcine follicle cells monolayer-cultured on type I and IV collagen, fibronectin or laminin. At 3 h in culture, laminin had the lowest rate of cell adhesion. In proliferation, type IV collagen induced the highest level of nuclear bromodeoxyuridine intake. In a functional differentiation, laminin had about 3 times as much triiodothyronine production as the other ECM molecules. In confluent culture cells, we also examined an expression of c-fos protein, a transcription factor that plays crucial roles in signal transduction. Immunocytochemistry detected the protein mainly in the nuclei. Western blot showed that laminin induced the highest level of its expression. Thyrotropin (TSH, 10 mU/ml) did not affect adhesion of the cells on any of the substrata or proliferation of the cells on fibronectin; nor did TSH affect c-fos protein expression of the cells on the substrata except for fibronectin. Our results suggest that type IV collagen and laminin, major components of basement membrane, play positive roles in proliferation and differentiation of follicle cells, respectively, while laminin has no positive effect on adhesion of the cells at early culture; that the cells express c-fos protein even in contact inhibition of growth and its expression is regulated in part by ECM; and that ECM controls some behaviors of the cells in a TSH-dependent or TSH-independent manner.

Animals↗
PubMed1995

A rare case of primary pulmonary choriocarcinoma in a male: immunohistochemical detection for human chorionic gonadotropin, epidermal growth factor (EGF) and EGF-receptor.

a rare case of primary choriocarcinoma of the lung in a male is described with immunohistochemistry for human chorionic gonadotropin (hCG), epidermal growth factor (EGF) and EGF-receptor. The extragonadal trophoblastic origin of this pulmonary carcinoma was definitely confirmed by an autopsy examination, and hCG-production and hCG-positive staining of the tumor cells. Furthermore, the tumor cells clearly expressed EGF and its receptor which play an important role in the proliferation and differentiation of normal and neoplastic trophoblasts of the uterus. Our present case suggests that EGF may act in an autocrine manner in the tumor cells of primary pulmonary choriocarcinoma.

Aged↗
PubMed1995

[Improvement of highly reproducible technique of four-vessel occlusion model and its study on metabolic changes of cerebral reperfusion in rats].

The four-vessel occlusion method introduced by Pulsinelli et al is widely used as an experimental model for reversible forebrain ischemia in rats. However, this model has a major problem in the difficulty assuring complete occlusion of the vertebral arteries by electrocauterization through the alar foramina of the first cervical vertebra. Anatomical basis of the vertebral artery suggested by Sugio et al indicates that the vertebral artery at the level of the second cervical vertebral is visible. In this study, we further developed highly reproducible model of reversible forebrain ischemia, which is modified four-vessel occlusion in rats. Male Wistar rats were subjected to four-vessel occlusion. Under microscope the visible vertebral arteries at the second vertebra could be easily electrocauterized and completely cut by microscissors to yield complete cessation of circulation of bilateral vertebral arteries without failure. After 24 hours, animals were subjected to 15, 30 and 45 minutes of forebrain ischemia by occluding both common carotid arteries with Sugita's temporary clips. 31P-magnetic resonance spectroscopy (31P-MRS) were obtained with a 6.3-T spectrometer to investigate sequential change of the in vivo brain energy metabolism. Our studies indicated that high energy phosphorus compounds were reduced in a few minutes after the induction of the forebrain ischemia, and they returned to the normal level after the recirculation. In addition, we monitored electroencephalogram (EEG) during the whole experimental period. The EEG showed a flat pattern after the induction of ischemia, and EEG recovered normal pattern within 12 hours.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Early changes of blood-brain barrier and superoxide scavenging activity in rat cryogenic brain injury.

Cryogenic brain injury results in blood-brain barrier (BBB) disruption which may be mediated in part by oxygen free radicals. In this study, sequential changes of BBB and endogenous superoxide scavenging activity were investigated in brains subjected to cryogenic injury. 92 male Wistar rats were sacrificed at 15, 30 minutes, 1, 2, 3, 4, 6, 24 and 48 hours after the lesion. The extent of BBB disruption was determined by quantitative assessment of Evans blue (EB) uptake based on extraction from tissue using dimethylformamide. Determination of endogenous superoxide scavenging activity in the injured brain was performed by electron spin resonance spectrometry using a spin trapping agent. Superoxide scavenging activity was significantly decreased within one hour after the injury relative to normal rat brain (p < 0.05, student's t test) persisting for at least 6 hours. The EB content in the lesioned hemisphere was significantly increased within one hour after the injury relative to the normal rat brain (p < 0.01) and continued to increase for 24 hours. In conclusion, early changes of BBB and endogenous superoxide scavenging activity in rat cryogenic injured brain indicate that BBB may be an early target for oxygen free radicals in cryogenic brain injury.

Animals↗