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Biomedical subjects

T Shirai

Publications and source records attributed to T Shirai.

At least 289 records · Page 16Linked to original sources

[A 76-year-old man with loss of vision and dementia].

We report a 76-year-old man who developed blurred vision and dementia. He was apparently well until April 4, 1990 (70-year-old at that time) when he had a sudden onset of bilateral loss of vision. Corrected vision was 0.1 (right) and 0.09 (left). He was admitted to the ophthalmology service of our hospital on April 9, 1990, and neurological consultation was asked on April 11. Neurologic examination revealed alert and oriented man without dementia. Higher cerebral functions were intact. He had bilateral large visual field defects with loss of vision; he was only able to count the digit number with his right eye and to recognize hand movement with his left eye. Otherwise neurologic examination was unremarkable. General physical examination was also unremarkable; he had no hypertension. Cranial CT scan was normal on April 11; lumber spinal fluid contained 1 cell/microliter, 63 mg/dl of sugar, and 97 mg/dl of protein; myelin basic protein was detected, however, oligoclonal bands were absent. He was treated with methylprednisolone pulse therapy and oral steroid, however, no improvement was noted in his vision. He started to show gaze paresis to left, ideomotor apraxia, agnosia of the body, and dementia. Cranial CT scan on June 11 revealed a low density area in the deep left parietal white matter facing the trigonal area of the lateral ventricle. He was discharged on July 2, 1990. Hasegawa dementia scale was 2/32.5 upon discharge. In the subsequent course, he showed improvement in his mental capacity and Hasegawa dementia scale was 22.5/32.5 in 1991, however, no improvement was noted in his vision. In 1994, he started to show mental decline in that he became disoriented, and showed delusional ideation of self persecution and depersonalization with occasional confusional state. He also showed unsteady gait. Cranial MRI on February 13, 1996 revealed a T2-high signal intensity lesion on each side of the parietal deep white matter more on the left and another T2-high signal intensity lesion in the left pons as well as in the right thalamus. He complained of right hypochondrial pain and was admitted to another hospital on April 22, 1996. He was markedly confused and demented. He continued to show bilateral loss of vision, but no motor palsy was noted. Cranial CT scan on April 23, 1996 revealed diffuse cortical atrophy and ventricular dilatation in addition to the low density areas in both parietal deep white matter. He developed jaundice in the middle of May. Abdominal CT scan revealed multiple low-to iso-density areas in the liver and marked iso-to high-density swelling of the right kidney. The patient expired on June 9th, 1996. The patient was discussed in a neurological CPC and the chief discussant arrived at the conclusion that the patient had had a carcinomatous limbic encephalitis with optic neuropathy and a choleduct carcinoma. Other opinions entertained included acute disseminated encephalomyelitis with optic neuritis, and granulomatous angiitis of the central nervous system. Some participants thought the primary site of the carcinoma was the right kidney with metastasis to the liver. Post mortem examination revealed a mixed type carcinoma in the right kidney with liver metastases. Neuropathologic examination revealed an incomplete softening in the optic chiasm and the left optic nerve, and in the left parieto-occipital areas. (The right hemisphere was frozen for future biochemical assay.) One of the adjacent cortical arteries had an organized thrombus. Other arteries and arterioles also showed sclerotic changes. Some of the leptomeningeal arteries were positive for Congored staining as well as for beta-amyloid immunostaining. Many senile plaques were seen diffusely in the cerebral cortex and neurofibrillary tangles were seen in the CA1 area and the parahippocampal gylus. No cellular infiltrations or demyelinated foci were seen. The neuropathologic features were consistent with circulatory disturbance based on the amyloid angiopa

Aged↗

[Neurological CPC.57. An 80-year-old woman with four years history of muscle atrophy involving lower extremities predominantly on the right side].

We report an 80-year-old woman with progressive muscular atrophy predominantly involving her right lower extremity. She was well until 1992 (75 years of age) when she noted an onset of weakness in her right leg which had got progressively worse. She was admitted to our service in July 1994. On admission, general physical examination was unremarkable. She was alert and well oriented without dementia. Higher cerebral functions were normal. Cranial nerves also appeared intact. She dragged her right leg in walking. Mild to moderate weakness (2/5 to 4/5) was noted in muscles in her right lower extremity more in the distal part. Deep tendon reflexes were within normal limits, and the plantar response was flexor bilaterally. Sensation was intact. Laboratory examinations were also unremarkable except for slight increase in CK which was 470 IU/l. CSF was also normal. EMG revealed neurogenic changes in the lower extremities. She was admitted to Aoki Hospital on October 21, 1994, by that time, her weakness in the right lower extremity had gotten worse in that the muscle strength of the right extensor hallucis longus was 0 and tibialis anterior 2; muscle atrophy was also prominent in her right leg; the right ankle jerk could not be elicited. In the subsequent course, weakness and atrophy appeared in her left lower extremity, however, upper extremities and cranial nerves had never been affected. Babinski sign was always negative. In February 1996, she developed delusional ideation of self persecution, and showed difficulty in communication with medical staffs. She developed fever of 38.7 degrees C on June 13, 1996 expired on the next day. The patient was discussed in a neurological CPC, and the chief discussant arrived at the conclusion that the patient had a form of spinal muscular atrophy. Opinions were divided between ALS and spinal muscular atrophy. Post-mortem examination revealed marked loss of anterior horn neurons in the lumbar area with astrogliosis. Bunina bodies were seen in some of the remaining neurons. No myelin pallor was noted in the pyramidal tracts, however, atrophy and loss of Betz cells were noted in the motor cortex. Other cortical areas were unremarkable. The neuropathologist arrived at the conclusion that the patient had ALS. This patient was unique in that she had asymmetric atrophy and weakness limited to the lower extremities. This is quite unusual as ALS of four years duration. In addition, the patient developed some mental change which was thought to represent dementia by some participants. But no clear morphologic changes were seen to account for her mental change.

Aged↗

[A case of pneumoconiosis (welder's lung) suspected to be lung cancer].

A 60-year-old man, employed as a welder for 25 years, was admitted with an abnormal shadow on chest X-ray. An ill-defined and solitary mass shadow 3 cm in diameter was subsequently detected in the left upper lung field. The mass shadow exhibited high attenuation on chest CT scan. Transbronchial lung biopsy (TBLB) revealed an organized lesion possessing a large quantity of iron. Although pneumoconiosis was suspected, the possibility of lung cancer could not be dismissed. Pneumoconiosis (welder's lung) was diagnosed after thoracotomy and examination of the resected mass. Pneumoconiosis (welder's lung) rarely presents as a solitary mass lesion.

Diagnosis, Differential↗

Dose-related increases in quantitative values for altered hepatocytic foci and cytochrome P-450 levels in the livers of rats exposed to phenobarbital in a medium-term bioassay.

The dose-response relationship between liver tumor promoting activity and cytochrome P-450 (CYP) induction by phenobarbital sodium (PB) was investigated using the liver medium-term bioassay system of Ito. Two weeks after a single dose of N-nitrosodiethylamine (DEN) (200 mg/kg body weight, i.p.), rats were given PB at dietary levels of 500, 250, 125, 60, 30, 15 and 8 parts per million (ppm) for 6 weeks. All rats were subjected to partial hepatectomy at week 3, and were killed at week 8. Quantitative values for glutathione S-transferase placental form positive hepatocytic (GST-P+) foci were increased in the high dose groups dose-dependently. In contrast, the values in the low dose groups were rather lower than that of the control. CYP2B1, 2C6 and 3A2 were predominantly immunostainable in hepatocytes around the central vein. While Western blotting revealed CYP2B1 and 2C6 proteins to be increased with strict dose-dependence, CYP3A2 was only elevated at high doses. Thus, a good correlation between increase of GST-P+ foci and CYP3A2 induction was observed, as well as with CYP2B1 and 2C6 in high dose groups.

Animals↗

Changing pattern of valve surgery.

BACKGROUND: Advances in surgical technique and perioperative myocardial protection have reduced the risk of aortic and mitral valve surgery. Improved methods of valve repair have reduced the proportion of patients who require valve replacement. However, patients who require valve replacement often have advanced disease and/or extensive calcification and may therefore be at increased risk for perioperative morbidity and mortality. METHODS AND RESULTS: We reviewed the results of 2898 patients who underwent aortic (AVR) or mitral (MVR) valve replacement at the Toronto Hospital. We compared patients who underwent surgery between January 1982 and December 1986 (early group) with those who were operated on between January 1989 and December 1993 (late group). The univariable and multivariable predictors of postoperative low-output syndrome (LOS) and operative mortality (OM) were determined for each time period. A total of 1779 patients underwent AVR (late, n = 997; early, n = 782). Multivariable analyses revealed that the late group had significantly more patients with independent pre-epidemiology operative risk factors for both OM and LOS. Despite the greater proportion of high risk patients, the incidence of postoperative LOS was lower in the late group (10% versus early, 14%; P = .012). There was no difference in OM between the two groups (late, 3.4% versus early, 3.7%; P = .732). A Total of 1119 patients underwent MVR (late, n = 493; early, n = 626). Compared with the early group, the late group had significantly more patients with preoperative multivariable risk factors for OM and LOS. There was no difference in postoperative LOS (late, 19% versus early, 21%; P = .361) or OM between the two groups (late, 5.8% versus early, 6.9%; P = .432). CONCLUSIONS: Despite an increase in high-risk patients, there was no significant increase in mortality or morbidity associated with aortic or mitral valve surgery.

Adult↗

Effects of low dose mixtures of four N-nitroso compounds on hepatic foci development in the rat.

Potential synergism between four N-nitroso compounds (nitrosomorpholine, nitrosodimethylamine, nitrosodiethanolamine, nitroso-oxazolidine) in rat liver carcinogenesis was examined in the medium-term bioassay. Male F344 rats were initially given diethylnitrosamine (DEN, 200 mg/kg, ip) and beginning 2 weeks later received test chemicals for 6 weeks individually at a full or 1/4 dose of that proven to be carcinogenic individually or in combination. All animals were subjected to partial hepatectomy at week 3 and killed at week 8. Induction of immunohistochemically-demonstrated glutathione S-transferase placental form (GST-P) positive foci was evaluated. The numbers and size of GST-P positive foci were significantly higher than the control levels by the treatment with each nitrosamine at full (1/1) and one quarter doses (1/4), excepting nitrosodiethanolamine and by combination of the four chemicals at 1/4 and 1/16. Because the dose-response curves were considered non-linear for most nitrosamines, synergistic effects were not apparent for the 1/4 mixture. Interestingly, however, the values for rats treated with these four chemicals in combination at the 1/4 dose level were almost the same as the average of four individual treatments at the full dose, and those for the 1/16 dose mixture were almost the same as the average of 1/4 individual treatment groups. These results indicate that these nitrosamines worked additively, rather than synergistically, in rat liver carcinogenesis.

Animals↗

Low susceptibility of the spontaneously hypertensive rat (SHR) to quinoline-induction of hepatic hemangioendothelial sarcomas.

Effects of quinoline and captafol, both of which are hemangiocarcinogenic agents, were investigated in spontaneously hypertensive rats (SHR). Male SHR and Wistar Kyoto rats (WKY), the parent strain of SHR, were administered quinoline (0.2%) or captafol (0.15%) supplemented in the diet for 32 weeks. Resultant incidences of hepatic hemangioendothelial sarcomas were in animals receiving quinoline 93% for WKY and only 7% for SHR. A few hepatocellular nodules were also induced in both strains. No histopathological lesions were observed in the other organs. Thus, the SHR proved unexpectedly less susceptible to vascular carcinogenicity than its WKY counterpart.

Animals↗

Selective reduction of V alpha 14+ NK T cells associated with disease development in autoimmune-prone mice.

A novel peripheral T cell subset characterized by the expression of a NK marker and invariant TCR encoded by V alpha 14 J alpha 281 gene segments with a 1-base N-region was investigated in relation to autoimmune disease development. First, we observed that invariant V alpha 14+ NK T cells are specifically reduced with aging in C57BL/6 lpr/lpr or MRL lpr/lpr mice, whereas no change was observed in age-matched control C57BL/6 or MRL +/+ mice as determined by FACS analysis and RNase protection assay. This reduction precedes the disease development and could also be detected in other autoimmune disease-prone mice, such as C3H gld/gld and (NZB x NZW)F1 mice. These results suggest that the specific decrease in invariant V alpha 14+ NK T cells correlates strongly with the development of autoimmunity. Second, injection of MRL lpr/lpr mice with anti-V alpha 14 mAb resulted in the early onset and exacerbation of lymphosplenomegaly due to the accumulation of abnormal CD3+ B220+ CD4-CD8- T cells as well as an increase in the titers of anti-dsDNA autoantibodies. These results indicate that V alpha 14+ NK T cells regulate autoimmune responses and play a crucial role in controlling the development of autoimmune diseases.

Age Factors↗

Effects of carbamate insecticides in a rat medium-term bioassay for hepatocarcinogens.

Ethiofencarb and pirimicarb, widely used insecticides, were investigated for hepatocarcinogenesis-modifying effects using a medium-term bioassay system for carcinogens. F344 male rats were given a single intraperitoneal injection of diethylnitrosamine (DEN, 200 mg/kg) and then, starting 2 wk later, received ethiofencarb in the diet at concentrations of 500 or 250 ppm, pirimicarb at 400 or 200 ppm, or a combination of ethiofencarb (250 ppm) and pirimicarb (200 ppm) for 6 wk. Control groups received DEN (200 mg/kg) or carbamate insecticides alone as stated earlier, without DEN. All rats were subjected to two-thirds partial hepatectomy at wk 3 and were killed at wk 8. Development of preneoplastic lesions, glutathione S-transferase placental form-positive foci, in the liver was significantly increased in terms of number receiving 500 ppm ethiofencarb. The results thus indicate that ethiofencarb at high dose possesses promoting activity for rat liver carcinogenesis.

Animals↗

Subchronic toxicity study of L-isoleucine in F344 rats.

A subchronic toxicity study with L-isoleucine was conducted using F344 rats. Groups of 10 rats of each sex were given diet containing 0, 1.25, 2.5, 5.0, or 8.0% L-isoleucine for 13 wk. No treatment-related effects were observed in terms of body weight change, food consumption or hematology. In both sexes given 8.0% L-isoleucine, increased or a tendency for increased urine volume and relative kidney weights were observed. Furthermore, the high-dose L-isoleucine treatment brought about an elevation of urinary pH and variations in serum electrolytes. However, histopathological alterations related to these changes were not observed in any organs of either sex. In conclusion, the present study demonstrated that L-isoleucine possessed minimal toxicity at dietary levels of 5.0% and 8.0%, while it did not exert any adverse affects at a dietary level of 2.5% or less.

Animals↗

Inhibitory potential of pregnancy and lactation on mammary carcinogenesis induced by a food-derived carcinogen, 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine, in Sprague-Dawley rats.

Effects of pregnancy and lactation on a food-derived carcinogen 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP)-induced mammary carcinogenesis were investigated in female Sprague-Dawley rats. When rats were administrated PhIP in the diet (100 ppm) for 15 weeks, palpable subcutaneous tumors were first detected at week 24 in three nulliparous rats, while tumor latency was apparently increased in animals undergoing delivery and weaning during the PhIP administration period. However, since the incidence of palpable tumors was not consistently increased in the nulliparous animals, possibly due to the short PhIP-treatment, and the fact that spontaneous tumors developed in parous animals after week 44, the final incidences and multiplicities of histopathologically confirmed adenocarcinomas at week 48 were not significantly different between the two groups. These findings art partly supported by the epidemiological evidence that breast cancer is more prevalent in nulliparous than in parous women.

Adenocarcinoma↗

Immunohistochemical demonstration of 3,2'-dimethyl-4-aminobiphenyl DNA adduct formation in various organs of Syrian golden hamsters.

3,2'-Dimethyl-4-aminobiphenyl (DMAB), known to be a wide-spectrum genotoxic carcinogen in rats, is also tumorigenic to hamster organs such as the forestomach, small and large intestines, gallbladder and urinary bladder. Using a specific antibody against DMAB-DNA adducts, adduct formation in various organs of Syrian golden hamsters after single s.c., i.g. or i.p. injections of DMAB was immunohistochemically examined in relation to its carcinogenic specificity. The nuclei of basal cells of forestomach, epithelia of small intestine, large intestine, gallbladder and urinary bladder of hamsters were stained to various degrees. However, no differences in the formation of DMAB-DNA adducts were observed between these and non-target organs regarding carcinogenicity. The staining intensity after i.g. or i.p. injections was slightly stronger than after s.c. injection. In line with previous findings for rats, the present results indicate that adduct formation is necessary but not itself sufficient for tumor induction in the Syrian golden hamster.

Aminobiphenyl Compounds↗

Inhibitory effects of phenolic compounds on development of naturally occurring preneoplastic hepatocytic foci in long-term feeding studies using male F344 rats.

Five phenolic compounds, namely caffeic acid, sesamol, hydroquinone, catechol, and 4-methoxyphenol, were fed to groups of 30 male F344 rats at dietary levels of 2, 2, 0.3, 0.8, and 2%, respectively, for 2 years. Retardation of body weight and elevated relative liver weights were noted for all groups. Formalin-fixed and paraffin-embedded liver tissues from rats killed terminally were cut and stained for glutathione S-transferase placental form (GST-P) and tumor growth factor alpha (TGF alpha) immunohistochemically. Numbers and areas of GST-P-positive (GST-P+) foci per unit area of liver section were measured, and the respective treated/control proportional values were calculated to be 58 and 57% for caffeic acid. 58 and 54% for sesamol, 71 and 71% for hydroquinone. 58 and 133% for catechol, and 49 and 39% for 4-methoxyphenol. These data were comparable with results obtained with medium-term liver bioassays (Ito test). However, no intergroup differences were detected with regard to quantitative findings for TGF alpha foci, which were relatively rare. Long-term inhibitory effects of phenolic compounds on liver carcinogenesis, predicted from the Ito test, were thus confirmed in the present feeding studies using quantitative analysis of immunohistochemically demonstrable GST-P+ foci as end point marker lesions.

Animals↗

CD40-mediated stimulation of B1 and B2 cells: implication in autoantibody production in murine lupus.

B1 cells usually show preferential responses to T cell-independent antigens. To ask whether B1 cells could respond to CD40-mediated stimulation for proliferation and differentiation, and whether CD40-mediated signals are involved in the production of autoantibodies by B1 cells, we compared responses to our newly established agonistic anti-mouse CD40 monoclonal antibody (mAb) between B1 and B2 cells from autoimmune-prone (NZB x NZW) F1 mice. Stimulation with this mAb induced a similar level of proliferative responses of both B1 and B2 cells, as well as an increase in expression of cell surface molecules I-A, CD54, CD23, CD80, and CD86. While co-stimulation with interleukin (IL)-4 markedly augmented proliferative as well as IgG1 and IgE antibody responses of both B and B2 cells, co-stimulation with IL-5 augmented proliferative and IgM antibody responses of only B1 cells. Splenic B1, but not B2 cells from young (NZB x NZW) F1 mice spontaneously produced substantial amounts of IgM including IgM anti-DNA antibodies, and the levels increased in case of stimulation with anti-CD40 mAb alone, or to a greater extent with the mAb plus IL-4 and IL-5. Collectively, these results indicate that splenic B1 cells from autoimmune (NZB x NZW) F1 mice have a comparable responsiveness to the CD40-mediated stimulation to that of B2 cells, which would be a potent regulatory mechanism involved in the spontaneous production of autoantibodies by B1 cells.

Animals↗

Ganglioside composition of the rat choriocarcinoma cell line, Rcho-1.

The Rcho-1 cell line, originally established from a rat choriocarcinoma, shows differentiation into placental trophoblastic giant cell-like cells and has been used to study the mechanism of placental function control. In the present study, we analysed the ganglioside composition of Rcho-1 cells by HPTLC orcinol/H2So4, TLC/ immunostaining and immunohistochemistry. Rcho-1 cells expressed GM3 and GD3 as the major gangliosides and CTH as major neutral glycolipid when they were cultured in growth medium (20% FCS) or transplanted beneath the kidney capsule. The expression of these gangliosides was strong in the undifferentiated small cells, whereas the completely differentiated giant cells showed poor staining with antibodies against the gangliosides. Under culture conditions to induce cell differentiation using horse serum (1-20% HS), the expression of GD3 was suppressed and re-expressed when the medium was changed to growth medium, suggesting that a change of ganglioside components may trigger and define the direction of terminal differentiation. Thus the composition of glycolipids is conserved in Rcho-1 cells and is similar to that of the rat placenta, where GM3 is dominant in mid-pregnancy and decreased in late pregnancy, whereas GD3 is low in mid-pregnancy and increased in late pregnancy.

Animals↗

Results of represervation of the chordae tendineae during redo mitral valve replacement.

BACKGROUND: Previous studies have shown that preservation of the chordae tendineae improves early and late postoperative left ventricular function after mitral valve replacement. This report describes the results of represervation of the chordae tendineae during redo mitral valve replacement in patients who had their chordae tendineae preserved during their initial operation. METHODS: Fifty-four patients undergoing reoperative mitral valve replacement with preservation of their chordal annular attachments (chordae group) were compared with 187 patients who had redo mitral valve replacement without preservation of the chordae (nonchordae group). The interval between the initial operation and the reoperation was 8.7 +/- 4.4 years in the chordae group and 8.6 +/- 4.9 years in the nonchordae group (p = 0.315). Seventy-three patients underwent aortic valve replacement during their redo mitral valve replacement compared with 168 patients who had mitral valve replacement alone. There were 15 patients who had their chordal attachments represerved during redo double-valve replacement. RESULTS: In the chordae group, intraoperative assessment revealed excellent chordal connection between the preserved papillary muscles and the mitral annulus in all patients. One patient had adhesions between the preserved chordae and the stent of the tissue valve. The chordal attachments were preserved during insertion of the second valve in all patients. The incidence of low output syndrome and operative mortality in the chordae group was 16.7% and 7.4%, respectively. In the nonchordae group, the incidence of low output syndrome was 27.3% (p = 0.112 compared with the chordae group) and the operative mortality was 13.4% (p = 0.236 compared with the chordae group). In patients with double-valve replacement, represervation of the chordae was associated with a reduction in low output syndrome (0% versus 24%; p = 0.034) and mortality (6.7% versus 15.5%; p = 0.374). CONCLUSIONS: Preservation of the chordal attachments between the papillary muscles and the mitral annulus can be accomplished during reoperative mitral valve replacement. Represervation of the chordae tendineae may reduce postoperative low output syndrome, especially in high-risk patients undergoing redo double-valve replacement.

Aortic Valve↗

Lack of carcinogenicity of tamarind seed polysaccharide in B6C3F1 mice.

The carcinogenic potential of tamarind seed polysaccharide was examined in both sexes of B6C3F1 mice. Groups of 50 male and 50 female animals were given diets containing 0, 1.25 and 5% of tamarind seed polysaccharide for 78 wk. Body weight retardation was exhibited by the females in the 1.25 and 5% groups from 34 wk to termination. However, there were no treatment-related clinical signs or adverse effects on survival rate, food and water consumption, haematology findings or organ weights. Detailed histopathological examination also revealed no treatment-related increase in the incidence of any non-neoplastic or neoplastic lesions. These results demonstrated that tamarind seed polysaccharide is not carcinogenic in B6C3F1 mice of either sex.

Animals↗

Anti-Ro/SSA associated recurrent annular erythema: autoimmune response to recombinant 60- and 52-kDa Ro/SSA proteins.

Recurrent annular erythema associated with anti-Ro/SSA antibody response has recently been recognized as a distinct clinical entity. Serum samples from 15 anti-Ro/SSA positive patients with recurrent annular erythema were tested by enzyme-linked immunosorbent assay (ELISA) for reactivity with full-length recombinant human 60-kDa and 52-kDa Ro/SSA proteins. All the 15 sera were positive for anti-60-kDa Ro/SSA, and 11 sera (73.3%) contained anti-52-kDa Ro/SSA. These results suggest the importance of 60-kDa polypeptide component of the Ro/SSA particle as a potential target in anti-Ro/SSA associated annular erythema.

Adolescent↗