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Biomedical subjects

T Nagashima

Publications and source records attributed to T Nagashima.

At least 145 records · Page 8Linked to original sources

[Expiratory ventilation and carbon dioxide production measured with a thermistor flow-through system].

A thermistor flow-through system for measuring expiratory volume without a mouthpiece and a nose clip was developed. First, a thermostat and a large syringe were connected to a box used to stimulate a subject's head. A carbon dioxide (CO2) gas mixture was driven through the box, while the output of a thermistor sensor of the thermistor flow-through system was recorded. The correlation between the area under the temperature-time curve and the actual volume of gas driven through the box was computed. Second, the effects of driving time, gas temperature, and room temperature on the area under the temperature-time curve were measured. Third, corrections for expiratory time and for the temperature of exhaled gas were derived from regression analysis of the relation between the time taken to drive the CO2 gas mixture and the area under the temperature-time curve, and between the temperature of the CO2 gas mixture and the area under the temperature-time curve, respectively. Fourth, CO2 production was computed from the area under the CO2 concentration-time curve (obtained at the same time as the temperature-time curve). To measure the temperature-time curve and the CO2-time curve for the simulator, the box was placed under the transparent hood of the thermistor flow-through system. To measure the temperature-time and CO2-time curves for a subject, the head was placed in the hood while the subject was supine. The subject breathed with the mouth held slightly open, and the mixture of room air and expired gas was continuously drawn at a constant flow through an outlet at the top of the hood. The outlet was connected to a flow meter and to a constant-speed blower. The CO2 concentration and the temperature in the hood exhaust were measured at the outlet, and were continuously recorded with a chart recorder. To measure the actual volume of CO2, a Douglas bag was also used, and was connected to the blower. Increases in the driving time and in gas temperature caused increases in the area under the temperature-time curve of 9%/sec and 6%/degrees C, respectively; increases in room temperature caused it to decrease at 7%/degrees C. After the thermistor-derived expiratory volume was corrected for expiratory time and temperature, it correlated significantly with expiratory volume as measured with a respiratory inductance plethysmograph. The correlation coefficients were +0.904 for expiratory volume and +0.881 for tidal volume. A significant correlation (r = +0.992) was also found between the volume of CO2 computed from the area under the CO2-time curve and the actual volume of CO2 delivered by the simulator. A similar correlation was found between CO2 production computed from the area under the CO2-time curve and the volume of CO2 collected in the Douglas bag during breathing. With corrections for expiratory time and temperature, and with the development of more advanced thermistor sensors, a thermistor flow-through method such as the one described here may be used to measure expired volume. Such a system may also be used to measure CO2 production in the clinical pulmonary function laboratory.

Adult↗

Effect of dexamethasone and prednisolone on insulin-induced activation of protein kinase C in rat adipocytes and soleus muscles.

We examined the effect of glucocorticoids on [3H]2-deoxyglucose ([3H]2-DOG) uptake, [125I]insulin binding, tyrosine kinase activity, and protein kinase C (PKC) activity in rat adipocytes and soleus muscles. In adipocytes, insulin-stimulated [3H]2-DOG uptake was decreased by prior 60-minute treatment with dexamethasone (DEX) or prednisolone (PSL), whereas [125I]insulin binding, insulin (INS) receptor autophosphorylation, and tyrosine kinase activity, as measured using exogenous substrate of poly(Glu80-Tyr20), were not significantly changed. Cytosolic PKC activity decreased and membrane-associated PKC activity increased during a 60-minute treatment of adipocytes and soleus muscles with DEX or PSL, indicating that both DEX and PSL stimulate the translocation and activation of PKC. However, pretreatment of adipocytes and soleus muscles with glucocorticoids resulted in reduced INS-stimulated translocation of PKC from cytosol to membrane. INS-induced decreases in cytosolic PKC activity (50% +/- 7% v 10% +/- 8% and 20% +/- 7%, P < .05 to .01, for nonpretreated [control], DEX pretreated, and PSL pretreated cells) and increases in membrane PKC (100% +/- 10% v 50% +/- 9% and 20% +/- 9%, P < .01, for control, DEX pretreated, and PSL pretreated cells) were larger in nonpretreated adipocytes than in adipocytes pretreated with glucocorticoids. These results raise the possibility that glucocorticoids, namely, DEX and PSL, stimulate the translocation and subsequent degradative downregulation of PKC, and that this may be pertinent to their inhibitory effects on INS-stimulated glucose transport.

Adipose Tissue↗

Intracerebral ring-enhancing lesions in a patient with multiple sclerosis: a case report.

BACKGROUND Intracerebral cystic lesions can easily be identified by computed tomography (CT) and magnetic resonance imaging (MRI). Cystic gliomas, brain abscesses, or metastatic carcinoma are the usual underlying causes for this neuroradiologic finding. CASE PRESENTATION We report here the case of a patient with multiple sclerosis who has two intracerebral cystic lesions. CONCLUSIONS Central nervous system (CNS) tissue destruction, necrosis, and cyst formation are very unusual in multiple sclerosis. Diagnostic difficulty therefore arises when patients suspected of having multiple sclerosis have radiologic evidence of cystic CNS lesions.

Adolescent↗

Effects of wortmannin on glucose uptake and protein kinase C activity in rat adipocytes.

Wortmannin is known to be an inhibitor of myosin light chain kinase and phosphatidylinositol 3-kinase (PI 3-kinase) (J. Biol. Chem. 268, 25846, 1993). We studied the effects of wortmannin on insulin- and 12-O-tetradecanoylphorbol 13-acetate (TPA)-induced glucose uptake, purified PKC activity and in vitro 80 kDa protein phosphorylation to elucidate the relationship between insulin-induced PI 3-kinase and PKC activations. Pretreatment with 10(-12)-10(-6) M wortmannin for 60 min resulted in a dose-responsive reduction of 10 nM insulin-stimulated glucose uptake in rat adipocytes. Pretreatment with 10(-6) M wortmannin resulted in 80% and 20% decreases of glucose uptake stimulated by insulin and TPA, respectively. Partially purified rat brain PKC activity and 80 kDa protein in vitro phosphorylation of rat adipocyte cytosol by addition of Ca2+ and phospholipid were dose-dependently decreased by 10(-8)-10(-6) M wortmannin; 20% decrease of PKC activity and 50% decrease of 80 kDa protein phosphorylation by 10(-6) M wortmannin were observed. These results suggest that wortmannin has a potent inhibitory effect on PI 3-kinase and a weak inhibitory effect on PKC activity, and both effects cause a significant inhibition of insulin-stimulated glucose uptake in rat adipocytes.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗

A novel point mutation (R243Q) in exon 7 of the c-erbA beta thyroid hormone receptor gene in a family with resistance to thyroid hormone.

Resistance to thyroid hormone (RTH) is characterized by variable tissue hyporesponsiveness to thyroid hormones. Recently, a large number of different point mutations have been identified in the c-erbA beta thyroid hormone receptor (TR beta) in subjects with RTH. We describe a Japanese family with RTH with a novel point mutation in exon 7 of the TR beta gene. A single nucleotide substitution, guanine for adenine, was identified at the second position of codon 243 located in the hinge domain between the ligand binding and DNA binding domains in one of the two alleles of the proband and his mother, resulting in the substitution of the normal arginine (CGG) with a glutamine (CAG). Except for one family, point mutations so far described in RTH are clustered at exons 8-10 of the TR beta gene. This report presents a novel mutation in the characteristic portion in exon 7 of the TR beta.

Amino Acid Sequence↗

A new algorithm for predicting splice site sequence based on an improvement of categorical discriminant analysis.

The splicing signals which govern the excision of introns are not yet well explained, since actual splice site sequences are to some extent different from the generally accepted consensus sequences. While a quantification method (categorical discriminant analysis: CDA) has been proposed to analyze splice site signals, sample sequences lying in the overlapping region of sample scores are not discriminated well by CDA, thus limiting the predictive ability of this analytical technique. In this paper, we propose a method to improve the performance of CDA, which is applicable to the analysis of 5'-splice site signals in various mammalian genes. The proposed algorithm has revealed a distinct enhancement in the predicting ability compared to that of traditional CDA and could explain point mutations in the 5'-splice site region of rabbit beta-globin gene fairly well.

Algorithms↗

A sex reversal infant with XX karyotype and complete male external genitalia.

The unusual case of a Japanese newborn XX male is presented. Examination of chromosomes in amniotic fluid cells had shown a normal female karyotype (46,XX), but ultrasonography revealed a penis and a scrotum. The neonate had normal male external genitalia, and serum levels of luteinizing hormone, follicle stimulating hormone, and testosterone were all within the normal range. High resonance chromosome analysis revealed an excess portion on the short arm of one of the X chromosomes. We examined his genomic DNA by polymerase chain reaction (PCR) and detected two Y specific regions in his genomic DNA, the sex-determining region Y (SRY) and pseudoautosomal boundary Y. Nucleotide sequencing of the PCR products of SRY indicated no mutation. These findings suggested that the translocation or insertion of an SRY region on the X chromosome led to the development of testicles and a male phenotype.

Base Sequence↗

Intradural spinal lipomas not associated with spinal dysraphism: a report of four cases.

Intradural spinal lipomas that are not associated with spinal dysraphism are rare. We report four cases of adult patients with intradural spinal lipomas. All of the patients were young adults, three women and one man, who ranged in age from 22 to 37 years (mean, 30.3 yr). The clinical presentation of these lesions varied, depending upon the size and location of each lipoma. It is interesting that the symptoms in the women gradually deteriorated during pregnancy or after delivery. Magnetic resonance imaging was very useful in determining the exact location of lipoma. In three of four patients, neurological improvement was obtained after decompressive laminectomy and partial removal of the lipoma.

Adult↗

Human interferon-beta therapy for cerebral primitive neuroectodermal tumors--two case reports.

A 5-year-old girl and a 2-year-old boy presented with recurrent cerebral primitive neuroectodermal tumor (PNET) and were treated with intravenous administration of human fibroblast interferon (HuIFN-beta) which was continued as outpatient maintenance therapy. Both patients showed a partial response and were still alive 14 months and 2 years after diagnosis. Our results suggest that HuIFN-beta is an effective therapy for PNET, and can be used as long-term maintenance therapy without serious side effects.

Brain↗

[Effect of 5'-deoxy-5-fluorouridine (5'-DFUR) on the activity of pyrimidine nucleoside phosphorylase (pyNPase) in normal and tumor tissues of human stomach].

PyNPase (pyrimidine nucleoside phosphorylase) activity and IL-1 alpha were measured in normal and tumor tissues of the specimens resected from gastric cancer patients who had been divided into two groups; one given preoperative 5'-DFUR (oral administration at a mean dose of 10.0 g) and one not given 5'-DFUR (control). PyNPase activities in both groups were higher in tumor than in normal tissues (p = 0.0001), but, less in tumor tissue of the preoperative administration group than the controls (p = 0.0376). IL-1 alpha levels in both groups were higher in tumor than in normal tissues (p < 0.01). Multiple regression analysis of the results showed that IL-1 alpha strongly influenced on PyNPase activity in tumor tissues (higher IL-1 alpha levels resulted in higher PyNPase activities in tumor tissues) (p = 0.0334).

Antineoplastic Agents↗

[Effects of separate administration of low-dose CDDP on antitumor immune reactivity for treatment of malignant glioma].

Recently, it has been reported that CDDP modifies the immune responses of tumor bearing hosts, but problem of the most appropriate treatment with CDDP to augment the host immunity remains unresolved. The purpose of this study was to determine the most advantageous administration of CDDP to increase both its cytotoxic effect and antitumor immune reactivity. Cell growth inhibition in vitro was assessed by MTT assay after treatment of U-251MG cells with various concentrations of CDDP for 24 or 120 hours. The results of this experiment showed that the growth of U-251MG cells in vitro was suppressed by CDDP in a dose-dependent as well as a time-dependent manner. Ten days after subcutaneous inoculation of human glioma cells, GL-9, in the rear flank of nude mice, they were assessed for growth suppression by CDDP. Totally, 20 ml/kg of CDDP was administered to each mouse; in one group (high-dose CDDP group), 5 ml/kg of CDDP on every fifth day, and in the other group (low-dose CDDP group), 2 ml/kg on every day. Measurement of the tumor volume in each group revealed no significant difference between the two groups in terms of the efficacy of tumor growth suppression. Twenty-one days after inoculation, we measured the splenic natural killer(NK) cell activity in each mouse. The results showed that NK cell activity was significantly increased in the low-dose cisplatin (2 ml/kg) group, and significantly decreased in the high-dose cisplatin (10 mg/ml) group, as compared to the control group. The results of our study suggest that the separate administration of low-dose CDDP is a useful treatment strategy for malignant glioma, because it increases the antitumor immune reactivity of hosts without decreasing the direct tumor cytotoxicity of CDDP.

Animals↗

[A case of tongue cancer effectively treated with tegafur].

We administered a slow-release formulation of tegafur (SF-SP) to a patient with cancer of the tongue. We would like to report the findings of this case which showed clear improvement. SF-SP was administered at 800 mg/day to a 58 year-old male for cancer of the tongue (T4N1). By the 17th day after the start of SF-SP administration, the tumor had shrunk, and by the 37th day the submandibular lymph nodes could not be located by touch. At the completion of the test on the 60th day, no cancer cells were detected. Following the completion of the test, there have been no symptoms of recurrence and a complete response was observed. At present, we are continuing administration of SF-SP and making observations.

Adenocarcinoma↗

[Osteoconduction in porous hydroxyapatite ceramics grafted into the defect of the lamina in experimental expansive open-door laminoplasty in the spinal canal].

We have investigated the osteoconduction in porous hydroxyapatite ceramics grafted into the defect of the lamina of dogs in expansive open-door laminoplasty. Porous Hydroxyapatite block (HAB) was sintered at 900 degrees C with size of 4 x 7 x 19 mm, a mean pore diameter of 90 microns and a void volume of 70%. The operation was performed in 29 dogs. The animals were sacrificed at three or at six months after the operation (the three-month group and the six-month group). After the grafted HABs with adjacent vertebrae were removed, the stability of the grafted HABs was manually evaluated. The HAB was firmly fixed to the laminae in 14 of 20 cases. It seemed that the stability of the HAB was poor in those cases in which the HAB had not been tightly sutured. To investigate osteoconduction, serial sections of the laminar bones including the HAB were prepared without decalcification and were examined histologically. New bone formation in the pores of the HAB was found in all cases. However, the osteoconduction rate was higher in the six-month group than in the three-month group (p < 0.01). And the osteoconduction rate was higher in those cases in which the HAB was firmly fixed to the laminae than in those with a loosely fixed HAB. Bone ingrowth in the HAB was frequently observed in the zone adjacent to the bone, more so than in other zones. Osteoconduction appeared to occur at the contact surface and to extend towards the center of the HAB.

Animals↗

[The relationship between infiltrating grade and prognosis by the preoperative diagnosis in ultrasonogram in breast carcinoma].

To evaluate peripheral infiltrative growth (inf) of breast catrcinomas as a prognostic factor, overall survival probabilities in 169 patients with tumor less than 5 cm in diameter were analysed in relation to the degree of inf (alpha, beta, gamma) using Kaplan-Meier method. There were statistically significant correlations between inf alpha and beta, inf alpha and gamma. On the other hand, the boundary echo (BE) observed at the peripheral margin of tumor in ultrasonogram is considered to reflect inf patterns of breast carcinomas. Therefore, BE was classified into three types as follows. Type I; negligible or regular thin marginal hyperecho. Type II; irregular thick marginal hyperecho. Type III; radiating boundary echo. These three types were matched to the patterns of infiltration so as to find any correlation between ultrasonogram and a corresponding histrogical specimen. Three types of ultrasonographic infiltrative grades (U-INF alpha, beta, gamma) were defined as follows. U-INF alpha; Type I BE is observed almost all surface of tumor. U-INF beta; Type II or III BE is observed in less than 50% of tumor surface. U-INF gamma; Type II or III BE is observed in over 50% of tumor surface. Total of 108 cases with tumor less than 3cm in diameter were received preoperative ultrasonographic studies. U-INF had highly significant correlation with inf and the occurrence of lymph node metastasis.

Adult↗

[Hydrodynamics of syringomyelia].

Abnormality of CSF hydrodynamics is an important factor of the pathogenesis of syringomyelia. Recent development of cine-MRI visualized real time CSF movement in the syrinx or subarachnoid space. In the present study, twenty cases of syringomyelia associated with Chiari I malformation, 10 cases of syringomyelia associated with spina bifida aperta, and 10 cases of syringomyelia associated with spina bifida occulta were studied with MRI and cine-MRI. The result demonstrated that hydrodynamics of these three groups were different to each other. Chiari I malformation showed CSF hydrodynamic abnormality at the foramen magnum and marked flow void in the syrinx. On the other hand, myelomeningocele showed hydrocephalus and less prominent flow void in the syrinx. Spinal lipoma which is the majority of spina bifida occulta showed no abnormality of CSF hydrodynamics. In conclusion, the selection of treatments should be individualized depending on the hydrodynamical abnormality of each patient.

Arnold-Chiari Malformation↗

Phorbol ester and insulin stimulate protein kinase C isoforms in rat adipocytes.

We examined effect of insulin or 12-O-tetradecanoyl phorbol 13-acetate (TPA) on the subcellular redistribution of protein kinase C isoforms in rat adipocytes. Total Mono Q column-elutable novel PKCs (nPKCs) which are Ca(2+)-independent and phospholipid-dependent protein kinases, decreased in the cytosolic fraction and increased in the membrane fraction during treatment with insulin or phorbol ester for 10 min. Immunoblot analysis of novel PKCs, -epsilon, -delta and -zeta, showed that insulin stimulated the translocation of these PKC isoforms from cytosol to membrane, similar to the translocation of conventional Ca2+/phospholipid-dependent PKCs (cPKCs), -alpha, -beta, and -gamma. Phorbol esters stimulated the translocation of PKC-alpha, -beta, -gamma, -epsilon and -delta, but not PKC-zeta. These results suggest that (a) insulin and phorbol esters similarly stimulate the translocation of each PKC isoform except for PKC-zeta, and (b) the translocation of both nPKCs and cPKCs occurs during insulin and TPA actions in rat adipocytes.

Adipocytes↗

Peritumoral brain edema associated with pediatric brain tumors: characteristics of peritumoral edema in developing brain.

The incidence and clinical significance of peritumoral brain edema in pediatric patients is not well understood. The purpose of this study is to clarify the clinical significance of peritumoral brain edema in pediatric patients. Seventy seven pediatric patients (under 15 year old) with brain tumor were studied by MRI. The volume of peritumoral edema and brain tumor were measured by integration of the cross-sectional area on serial MRI. The severity of brain edema was expressed by the ratio of edema volume to tumor volume. The results were compared with that of 408 adult patients with brain tumor. Incidence of the brain edema associated with supratentorial tumors is lower in pediatric group than in adult. Severity of brain edema is also less extent in the pediatric group. Forty two percent of supratentorial gliomas in pediatric group showed peritumoral edema. On the other hand, 63% of adult group showed peritumoral brain edema. In general, pediatric brain tumors rarely associated with marked peritumoral brain edema which observed in the adult group. However, intraventricular or paraventricular tumors with obstructed hydrocephalus showed remarkable brain edema in pediatric group. Low incidence and less severity of peritumoral edema are caused not only by histological bias of tumors, but also by the biological nature of developing brain.

Adolescent↗