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Biomedical subjects

T Murakami

Publications and source records attributed to T Murakami.

At least 271 records · Page 15Linked to original sources

Cell surface expression of immature H glycoprotein in measles virus-infected cells.

Two forms of hemagglutinin (H) protein, one with an apparent molecular mass of 78 kDa (78K H protein) and the other with that of 74 kDa (74K H protein), are present in cells infected with measles virus (MV). We previously observed that only the mature 78K H protein, a completely glycosylated form of the 74K H protein, was expressed on the cell surface of the infected cells. In the present study, we detected transient expression of the 74K H protein on the cell surface of infected cells by pulse-chase studies, although the level of this expression was much lower than that of the 78K H protein. On the cell surface the 74K H protein was present as dimers and sensitive to endo-beta-N-acetylglucosaminidase H digestion. Treatment with brefeldin A, which blocks the transport of membrane and secretory proteins from the endoplasmic reticulum to the Golgi apparatus, inhibited the cell surface expression of the 78K H protein, but not that of the 74K H protein. These data suggest that a part of the MV 74K H proteins could be transported directly to the cell surface - probably via an alternative pathway - without processing to the complex form in the Golgi apparatus.

Animals↗

Effects of growth on the response of the rabbit patellar tendon to stress shielding: a biomechanical study.

OBJECTIVE: To know the effect of stress deprivation on the dimensions and mechanical properties of the patellar tendon during growth. DESIGN: The dimensions and tensile properties of stress-shielded patellar tendons were studied in growing rabbits and compared to those in mature animals. BACKGROUND: Although the effects of stress deprivation on the remodeling of ligaments and tendons have been studied in various animal models, the effect of growth on the remodeling has not been studied well. METHOD: A stress shielding technique was applied to 1-, 2-, and 3-month-old Japanese white rabbits to completely remove stress in the patellar tendons for 4, 7, and 14 days. Changes in the dimensions and mechanical properties as well as fibroblast density of the tendon were determined. RESULTS: The tensile strength and tangent modulus of the patellar tendons were markedly decreased by stress shielding, while the cross-sectional area was significantly increased, with the largest changes in 1-month-old rabbits. Fibroblast density also increased; however, the degree of increase was highest in 3-month-old rabbits. CONCLUSION: The changes in the dimensions and mechanical properties of the patellar tendons induced by stress shielding were greater in younger animals. RELEVANCE: The biomechanical response of tendons and ligaments to stress deprivation induced by, for example, limb immobilization is greater and occurs earlier in younger subjects, which is important for the surgical treatment and rehabilitation protocol of joint diseases in young subjects.

Age Factors↗

Time-dependent changes of decorin in the infarct zone after experimentally induced myocardial infarction in rats: comparison with biglycan.

Decorin, a small dermatan sulphate proteoglycan, has been postulated to interact with other components of the extracellular matrix. We examined time-dependent changes of decorin in the infarct zone after experimentally induced myocardial infarction in rats by Northern blotting, in situ hybridization, and immunohistochemistry. The expression of decorin mRNA was compared to that of biglycan mRNA. Northern blotting demonstrated that the decorin mRNA expression was not increased in the infarct zone on day 2, while increased biglycan mRNA was observed at that time (average 3.1-fold increase). Decorin mRNA expression was increased on day 7, and reached a peak (average 2.2-fold increase) around day 14. Biglycan mRNA expression also reached a peak level around day 14 (average 13.3-fold increase). In situ hybridization revealed that mRNA signals for decorin did not appear in the infarct zone on day 2, while biglycan mRNA signals were observed. Decorin mRNA signals were observed in spindle-shaped mesenchymal cells in the infarct peripheral zone on day 7. The decorin mRNA signals appeared later than those of biglycan. Immunopositive staining for decorin was observed in the infarct zone on day 7. The present results demonstrated a time-dependent increase in decorin mRNA expression in mesenchymal cells in the infarct zone in rats. Decorin mRNA appeared later and was increased to a lower extent in the infarct zone than biglycan mRNA.

Animals↗

Absence of somatic RET gene mutation in sporadic parathyroid tumors and hyperplasia secondary to uremia, and absence of somatic Men1 gene mutation in MEN2A-associated hyperplasia.

Germline mutations of the MEN1 gene are found in more than 85% of multiple endocrine neoplasia type 1 (MEN 1) patients, and germline mutations of the RET gene are found in more than 95% of multiple endocrine neoplasia type 2 (MEN2) patients. Parathyroid hyperplasia is seen in more than 90% of MEN 1 and about 15% of MEN2A patients. To date, somatic MEN1 mutations are reported in about 20% of sporadic parathyroid tumors. To elucidate the genetic basis of parathyroid tumor development, we examined somatic RET gene mutations in sporadic parathyroid tumors and hyperplasia secondary to uremia, and somatic MEN1 gene mutations in parathyroid hyperplasia from MEN2A patients. A total of 145 parathyroid tumors comprising 129 sporadic parathyroid tumors, 14 hyperplastic lesions secondary to uremia, and two hyperplastic lesions from MEN2A patients were examined. DNA was extracted from fresh frozen parathyroid tissue. Exons 2-10 of the MEN1 gene and exons 10 and 11 of the RET gene were sequenced. No somatic RET gene mutations were found in the 129 sporadic parathyroid tumors or 14 parathyroid hyperplastic lesions secondary to uremia. No somatic MEN1 gene mutations were found in the two parathyroid hyperplasia from MEN2A patients. These data suggest that RET gene mutation may not be involved in the development of sporadic parathyroid tumors and hyperplasia secondary to uremia and that MEN1 gene mutation may not be or is rarely associated with development of parathyroid hyperplasia in MEN2A patients.

Aged↗

Usefulness of quick intraoperative measurements of intact parathyroid hormone in the surgical management of hyperparathyroidism.

We investigated the use of quick measurement of intraoperative intact parathyroid hormone (I-PTH) to predict the outcome of parathyroidectomy. We examined intraoperative monitoring of I-PTH in 34 consecutive primary hyperparathyroidism (pHPT) patients operated on between April and December 1999. The average patient age was 56 +/- 13 years, and all but one were women. Four had a history of thyroidectomy. Blood samples were drawn before excision of enlarged parathyroid gland(s) and at 2, 5, 10, and 15 minutes afterward. Plasma I-PTH was measured by a two-site immunochemiluminometric assay. Twenty-three patients were shown to have single gland disease, and ten had multiglandular disease. All patients, except one, underwent successful parathyroidectomies. The plasma I-PTH value 15 minutes after removal of enlarged gland(s) had dropped to 26 +/- 10% of pre-excision I-PTH value. In one patient with a previous history of thyroidectomy for thyroid papillary cancer, no gland enlargement was found in the area where the lesion had been suggested by both ultrasonography and 99mTc sestamibi scanning. In this case, intraoperative measurements of I-PTH in the bilateral internal jugular veins identified an ectopic parathyroid tumor, which was successfully removed. We conclude that quick measurement of intraoperative I-PTH is a valuable tool for decision-making, especially for reoperative parathyroid surgery, for patients with previous history of thyroidectomy, and for patients in whom unilateral neck exploration or a single-gland approach is scheduled based upon preoperative localization.

Female↗

Effects of carbamazepine on acetylcholine release and metabolism.

To clarify the mechanisms of action of carbamazepine (CBZ), we investigated the effects of CBZ on acetylcholine (ACh) release and metabolism in rat striatum and hippocampus. Acute administration of effective dose of CBZ (25 mg/kg) increased both striatal and hippocampal extracellular levels of ACh, whereas a supraeffective dose of CBZ (50 mg/kg) did not affect the levels and a toxic dose of CBZ (100 mg/kg) decreased the extracellular ACh levels in both brain regions. Both acute and chronic administrations of CBZ (25 and 50 mg/kg, mg/kg per day) increased intracellular ACh levels in striatum and hippocampus. The striatal intracellular ACh levels were decreased by both acute and chronic administrations of CBZ (100 mg/kg, mg/kg per day), whereas the hippocampal intracellular ACh levels were not affected. The effective CBZ concentration did not affect cholinesterase activity, whereas supraeffective CBZ concentration reduced it weakly. Effective dose of CBZ enhanced ACh release and synthesis; however, supraeffective doses of CBZ reduced ACh release and synthesis without enhancement of ACh degradation, indicating that CBZ has biphasic effects on ACh release and synthesis. Thus, the present findings, the slight stimulation of ACh function by effective dose of CBZ, are involved, at least partially, in the antiepileptic and mood stabilizing mechanisms of action of CBZ.

Acetylcholine↗

Enhancing effect of 5 alpha-cyprinol sulfate on mucosal membrane permeability to sodium ampicillin in rats.

Effect of 5 alpha-cyprinol sulfate, a bile alcohol sulfate specific to carp bile, on rectal membrane permeability to sodium ampicillin (AMP Na) was examined in rats. AMP Na is not easily absorbed through rat rectal membrane without aid. 5 alpha-Cyprinol sulfate significantly enhanced the rectal membrane permeability to AMP Na even at a low concentration (6.25 mM), though sodium taurocholate needed a higher concentration (25 mM). Co-administration of phosphatidylcholine significantly suppressed the enhancing action of both sodium taurocholate and 5 alpha-cyprinol sulfate. On the other hand, calcium ion did not suppress the action of 5 alpha-cyprinol sulfate, although it did clearly suppress the action of sodium taurocholate. In conclusion, 5 alpha-cyprinol sulfate was found to have a potent enhancing effect on mucosal membrane permeability to water-soluble compounds. The enhancing mechanism of 5 alpha-cyprinol sulfate appeared to be different from that of sodium taurocholate.

Ampicillin↗

Multishot echo-planar imaging with gadopentetate dimeglumine. Preliminary study of efficacy for detection of hypovascular metastatic liver tumors.

OBJECTIVE: To evaluate the usefulness of sequential T2-weighted spin-echo type multishot echo-planar (T2-EP) imaging with gadopentetate dimeglumine for the detection of hypovascular metastatic liver tumors. MATERIAL AND METHODS: Fifteen consecutive patients with 56 proven hypovascular metastatic liver tumors were included in the study. Three observers blindly and independently read the whole-liver images obtained with T2-weighted spin-echo, T2-weighted single-shot fast spin-echo, T1-weighted fast multiplanar spoiled GRASS and T2-EP images obtained before and 25, 60, 90 and 120 s after injection of 0.2 mmol/kg b.w. of gadopentetate dimeglumine. The diagnostic accuracy was estimated by calculating the area under the observer-specific binomial receiver operating characteristics curves (Az). RESULTS: T2-EP images obtained 60 s after contrast injection showed significantly higher contrast-to-noise (C/N) ratios than the other imaging techniques. A combination of all phases of the T2-EP images produced the highest sensitivity and specificity. In terms of the Az value, the diagnostic accuracy for tumor detection achieved with a combination of all phases of the T2-EP images was significantly higher than that with T1-SPGR and T2-SSFSE images (p<0.01). The Az values of the T2-EP images (Az=0.975) were higher than those of T2-CSE images (Az=0.948), but the difference was not significant. CONCLUSION: Our preliminary study revealed that sequential imaging with enhanced T2-EP images was useful for the detection of hypovascular metastatic liver tumors because of its superior C/N ratio and sensitivity.

Adult↗

Malignant schwannoma with melanocytic differentiation arising in a patient with neurofibromatosis.

A 50-year-old woman with von Recklinghausen's disease, but not Carney's complex, presented with a 1-year history of a hard subcutaneous mass on her right hip and right inguinal lymphadenopathy. Histological and immunohistochemical studies of the tumour revealed schwannian and melanocytic characteristics. Local recurrence without distant metastases was observed 5 years later. Although the diagnosis of malignant schwannoma with melanocytic differentiation, rather than neurotropic melanoma, was made for the primary tumour, based on the clinicohistopathological and ultrastructural findings, the overall clinical course in this case did not seem incompatible with malignant melanocytic schwannoma.

Cell Differentiation↗

Dilazep, a nucleoside transporter inhibitor, modulates cell cycle progression and DNA synthesis in rat mesangial cells in vitro.

The direct effects of the nucleoside transporter inhibitor dilazep on the cell cycle of mesangial cells have not before been investigated. The purpose of this study was to elucidate whether dilazep can inhibit the proliferation of mesangial cells and how it interferes with the cell cycle of these cells. DNA histograms were used and BrdUrd uptake rate was measured by flow cytometry. There was no significant difference in the cell numbers among the untreated group and the 10(-5) M, 10(-6) M or 10(-7) M dilazep-treated groups at 24 h of incubation. However, at 48 and 72 h, the cell numbers in the dilazep-treated groups were significantly lower compared with that of the untreated group (P < 0.005). The DNA histograms of cultured rat mesangial cells at 12, 24, and 48 h of incubation with 10(-5) M dilazep showed that the ratio of the S phase population in the dilazep-treated group decreased by 2.2% at 12 h, by 9.6% at 24 h, and by 18.9% at 48 h compared with the untreated group. The ratio of the G0/G1 phase population in the dilazep-treated group significantly increased: 6.8% at 12h (P < 0.05), 13.9% at 24 h (P < 0.001), and 76.5% at 48 h (P < 0.001) compared with the untreated group. A flow cytometric measurement of bivariate DNA/BrdUrd distribution demonstrated that the DNA synthesis rate in the S phase decreased after 6 h (P < 0.005) and 12 h (P < 0.05) of incubation compared with the untreated group. These results suggest that dilazep inhibits the proliferation of cultured rat mesangial cells by suppressing the G1/S transition by prolonging G2/M and through decreasing the DNA synthesis rate.

Animals↗

Induction of differentiation of leukaemic (HL-60) or prostate cancer (LNCaP, JCA-1) cells potentiates apoptosis triggered by onconase.

Onconase (Onc) is a ribonuclease from amphibian oocytes that is cytostatic and cytotoxic to many tumour lines. It shows in vivo antitumour activity in mouse tumour models and is currently in Phase III clinical trials. The present study was designed to test whether cytotoxic effects of ONC can be modulated by differentiating agents. Human leukaemic HL-60 and prostate cancer LNCaP and JCA-1 cells were treated with Onc in the absence and presence of several inducers of differentiation and frequency of apoptosis was assessed using three different cytometric methods and confirmed by analysis of cell morphology. A moderate degree of apoptosis observed after 48-72 h incubation of HL-60 cells in the presence of 0.42 microM Onc alone was markedly potentiated by administration of retinoic acid (all trans), sodium butyrate or dimethylsulfoxide at concentrations known to induce differentiation but be minimally cytotoxic. Likewise, the frequency of apoptosis of LNCaP and JCA-1 cells treated with Onc was increased in the cultures to which phenylbutyrate was added. Although cell treatment with Onc alone, with each of the differentiating agents alone or with Onc in combination with the differentiating agents led to an increase in the proportion of G1 cells, no specific cell cycle phase preference in induction of apoptosis was observed. The data suggest that cells undergoing differentiation are particularly vulnerable to Onc; a combination of Onc and differentiating agents should be considered for further in vivo tests to assess its possible usefulness in the clinic.

Antineoplastic Agents↗

Rupioid psoriasis with arthropathy.

A 31-year-old male presented with limpet-like, cone-shaped skin lesions on the scalp, the extremities, and the trunk of 4 months' duration, and had had severe joint pain in his right fingers, wrist, and knee for 1 month. Radiological examination revealed arthritis of the above mentioned multiple joints. Rheumatoid factor was serologically negative. Histopathological findings showed dense inflammatory cell infiltration and remarkable Munro's microabscesses in the horny layer in addition to psoriasiform epidermal hyperplasia, and predominant dermal oedema. Based on clinicopathological findings, a diagnosis of rupioid psoriasis with arthropathy was made. Following treatment for arthralgia using low doses of systemic steroid, the effects of cyclosporin combined with topical steroids was seen to alleviate dramatically the skin lesions and arthritis within 2 weeks. There was no recurrence of such skin and joint lesions during a follow-up period of 1 year.

Administration, Topical↗

Masticatory movement in two cases with unusual alignment of the maxillary canine.

Masticatory function was analysed before and after orthodontic treatment in two cases where tooth alignment remained unusual after treatment. The Sirognathograph Analyzing System was used to analyse the masticatory function. In both cases, the right maxillary first premolar was located where the maxillary canine is normally positioned. The results of orthodontic treatment were satisfactory both morphologically and aesthetically, and masticatory function was greatly improved. However, some problems remained in the mandibular movement due to the abnormal contact between the mandibular teeth and the maxillary first premolar. These findings support the need for examination of masticatory function when treating patients with an unusual tooth alignment even if the results of orthodontic treatment are both morphologically and aesthetically successful.

Adolescent↗

Endomyometriosis arising in the uterosacral ligament: a case report including a literature review and immunohistochemical analysis.

We report a case of endomyometriosis arising in the left uterosacral ligament of a 29-year-old woman. The central cavity of the uterine-like mass was lined by pseudo-stratified columnar epithelium and endometrial stroma. The wall of the cyst consisted of bundles of smooth muscle cells. Immunohistochemical analysis demonstrated both alpha-estrogen receptor and progesterone receptor immunoreactivities in the epithelial, stromal and smooth muscle cells. A relatively high proliferating activity was also demonstrated in these cells by Ki-67 immunostaining. These findings suggest that the mass was hormone dependent and had a relatively rapid evolution.

Adult↗