Biomedical subjects

M Shimada

Publications and source records attributed to M Shimada.

At least 649 records · Page 36Linked to original sources

PubMed1990

[2,450MHz hyperthermia for malignant stenosis of the bile duct--development of a new biliary drainage tube united with a thermocouple].

We have developed new biliary drainage tubes (10 Fr and 12 Fr size) united with a thermocouple, through which we could apply 2,450MHz hyperthermia more exactly monitoring the tissue temperature in 3 cases with biliary obstruction than intracatheter hyperthermia methods already reported. One patient was discharged asymptomatic without jaundice after the removal of the drainage tube.

Aged↗

PubMed1990

Effect of growth hormone on rat hepatic cytochrome P-450f mRNA: a new mode of regulation.

Growth hormone (GH) is known to be involved in the control of rat hepatic drug and steroid metabolism through its action on cytochrome P-450s. To examine the role of GH in the regulation of cytochrome P-450f (P-450f), a full-length cDNA clone corresponding to P-450f was isolated and the 3'-non-coding region was utilized for Northern and slot-blot analyses. P-450f mRNA levels were low in neonates, increased after age 4 weeks in male and female rats, and were approximately 3 times higher in the liver of adult female rats than male rats. Hypophysectomy caused a significant decrease in P-450f mRNA levels in male and female rats. Intermittent injection with human growth hormone (hGH) to mimic the male secretory pattern of GH caused a 9-fold increase in P-450f mRNA in hypophysectomized male rats to levels near male control levels, whereas continuous administration of hGH to mimic the female secretory pattern caused a greater increase in P-450f mRNA levels in male and female hypophysectomized rats (25-fold and 9-fold respectively) to levels nearer female control levels. The responses of the other GH-stimulated P-450s, P-450-male and P-450-female, to the different modes of hGH treatment were different from that of P-450f. Since sex hormones are known to affect the regulation of other P-450s, the effect of sex hormones on P-450f mRNA was studied. Ovariectomy caused a 2.4-fold reduction in P-450f mRNA which was partially reversed by estradiol treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1990

Regional excitatory and inhibitory amino acid levels in epileptic El mouse brain.

Inbred mutant El mice are highly susceptible to convulsive seizures upon "tossing" stimulation. The levels of excitatory (e.g. glutamate and aspartate) and inhibitory amino acids [e.g. gamma-amino-butyrate (GABA)] were examined in discrete regions of stimulated El mice [El(+)], non-stimulated El mice [El(-)] and ddY mice, which do not have convulsive disposition. In comparison with ddY, a general increased levels of aspartate, glutamate, glutamine, and taurine were detected in brain regions of El(-). The levels of GABA and glycine were almost the same in ddY and El(-). Compared to El(+), the levels of aspartate, glutamate, glutamine, and GABA in El(-) were either the same or higher. In the case of taurine and glycine, the levels in El(-) were either the same or lower than El(+). Alanine is special in that El(-) have a higher level than El(+) in hippocampus but lower in cerebellum. Furthermore, while marked changes were registered in several brain regions, none of the amino acids investigated showed any significant differences in the hypothalamus of three different groups of mice.

Amino Acids↗

PubMed1990

Incidence of neuroblastoma in Sapporo city.

The incidence of neuroblastoma in Sapporo City for the period before the enforcement of the mass screening of neuroblastoma (1974 to 1980) was compared with the period after it (1981 to 1987). No large difference was found in incidence between them. In 1981 to 1987 the occurrence cluster at 2 to 4 years of age found in the prescreening period disappeared and an accumulation of patients at 0 year of age was noted. The sensitivity of the mass screening was almost stable (76.9% to 80.0%) throughout the 7 years. By the mass screening system of Sapporo City, early detection will be expected in 60% to 70% of all the neuroblastoma patients, the deficiency of which is due to the patients who neglected the mass screening.

Adolescent↗

PubMed1990

Amino acid content in several brain regions of the active and hibernating frog, Rana esculenta.

1. Total free amino acid contents in the optic lobe and diencephalon increased significantly during hibernation. 2. Free glutamate + glutamine showed significant increases in the cerebral hemisphere, optic lobe, medulla oblongata and diencephalon. 3. Free aspartate + asparagine showed significant increases in the cerebral hemisphere, optic lobe, diencephalon and olfactory lobe. 4. GABA showed a significant change only in the medulla oblongata. 5. Total protein amino acid level in the cerebellum and olfactory lobe decreased significantly during hibernation and most of the amino acids decreased significantly in these regions. 6. The amino acid metabolism during amphibian hibernation differs from that of the mammal.

Amino Acids↗

PubMed1990

Electron microscopic study on the homozygote (Ml/Ml) of the macular mutant mouse.

The macular mouse is a mutant mouse with a defect in copper transport and an X-linked recessive inheritance. Its hemizygote (Ml/y) is considered to be an appropriate model fo Menkes kinky hair disease (MKHD). In this study, homozygote (Ml/Ml) were bred by coupling CuCl2-treated Ml/y with heterozygote (Ml/+). Both Ml/Ml and Ml/y die around day 15 of age. However, treatment with CuCl2 enables them to live until adulthood. The brains of Ml/Ml were chronologically examined by light and electron microscopy. In the non-treated Ml/Ml, abnormal mitochondria increased in number in the cerebral cortical neurons and in the cerebellar Purkinje cells from day 7 to 14 of age. In the treated Ml/Ml, the administration of CuCl2 improved the abnormality of the mitochondria in the cerebrum by day 20, but those in the Purkinje cells remained until day 60. Flattened cisterns and intracytoplasmic inclusions were also observed in the Purkinje cells of treated Ml/Ml. These ultrastructural changes were quite similar to those observed in the Ml/y. Our mutant mice (treated Ml/Ml), when they are coupled with treated Ml/y, can give birth to offspring, all of which will be genetically Ml/y or Ml/Ml. These fetal mice will be very helpful for studying the pathological and biochemical condition of prenatal MKHD.

Animals↗

PubMed1990

Reorganization of the corticospinal tract following neonatal unilateral cortical ablation in rats.

The corticospinal tract in the rat after neonatal ablation of the unilateral cerebral cortex was studied morphologically and histochemically using the retrograde and antegrade horseradish peroxidase (HRP) tracing methods. The normal corticospinal tract in the lumbar cord was composed of a number of small and some large axons. In the atrophic corticospinal tract related to the ablated cerebral cortex, the small axons were decreased in number two weeks after the operation. However, new myelinated small axons appeared around day 28 and their diameters increased gradually from after day 56 to day 84. The original large axon in the atrophic corticospinal tract was much more increased in size than that in the corticospinal tract of the non-operated-on control. When HRP was injected into the left cervical cord of the adult rat whose right cerebral cortex had been ablated during the neonatal period, a considerable number of HRP-labeled neurons was seen in the healthy left cerebral cortex. When the corticospinal tract was traced antegradely by injecting HRP into the healthy left cerebral cortex, an aberrant corticospinal tract reaching into the ipsilateral dorsal funiculus was observed. These results give a morphological basis for the well known fact that children who have had brain damage during the neonatal period and early infancy have the capacity for recovery of motor function.

Animals↗

PubMed1990

Possible direct effect of diethylcarbamazine on the infective larvae of Brugia pahangi.

The direct action of diethylcarbamazine (DEC) on the infective larvae of Brugia pahangi was studied. The larvae were cultured in RPMI 1640 supplemented with foetal bovine serum and antibiotics for 22 days. Most of the larvae remained alive for 8 days, but survival rate of larvae decreased rapidly from day 10 onwards. The larvae did not grow in the culture system. The addition of DEC did not affect the morbidity of the larvae and no difference was observed in the morphological characteristics between the larvae cultured in the presence or absence of DEC. The infective larvae were cultured in vitro for 5 days in the presence or absence of DEC, and inoculated into jirds. The animals were necropsied at intervals, and developing larvae and adult worms were recovered. When the larvae were cultured without DEC and then inoculated subcutaneously into jirds, 29.8% of the inoculum was recovered 3-15 days, and 25% 19-22 weeks, post-inoculation. However, when the larvae were exposed to DEC in vitro and inoculated into jirds, the rate of recovery was reduced to 25% 3-15 days post-inoculation and 2% after 19-22 weeks. When the control larvae cultured in vitro were inoculated intraperitoneally into jirds, 41.3% of inoculum was recovered 3-15 days, and 42.8% 19-22 weeks, post-inoculation. Again the corresponding value for larvae exposed to DEC in vitro was reduced to 19.8% 3-15 days, and 8% 19-22 weeks, post-inoculation. It was observed that the larvae exposed to DEC in vitro were retarded in their development in jirds.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1990

Analysis of very long-chain fatty acids and plasmalogen in the erythrocyte membrane: a simple method for the detection of peroxisomal disorders and discrimination between adrenoleukodystrophy and Zellweger syndrome.

We analyzed the sphingomyelin very long-chain fatty acids (VLCFAs) and phosphatidylethanolamine (PE) plasmalogen contents of the erythrocyte membrane in patients suffering from peroxisomal disorders. In a patient with Zellweger syndrome, both a decrease in the PE plasmalogen content and an increase in the sphingomyelin VLCFAs content of the erythrocyte membrane were noted. In patients with adrenoleukodystrophy, however, there was no decrease in PE plasmalogen, although the sphingomyelin VLCFAs content of the membrane was significantly increased in comparison with control values. Analyses of both sphingomyelin VLCFAs and PE plasmalogen were carried out simultaneously, using both the same process and the same sample.

Adrenoleukodystrophy↗

PubMed1990

Primary T-cell lymphoma with myelopathy associated with HTLV-1.

The case of a patient who had myelopathy associated with human T-cell lymphotropic virus Type 1 (HTLV-1) for 10 years and developed a T-cell lymphoma in the cerebellum is reported. The relationship between myelopathy associated with HTLV-1 and primary T-cell lymphoma is discussed.

Cerebellar Neoplasms↗

PubMed1990

Amplification and specific detection of transforming gene region of human papillomavirus 16, 18 and 33 in cervical carcinoma by means of the polymerase chain reaction.

We have established a highly sensitive method for specific detection of human papillomavirus (HPV) 16, 18 and 33, by using the polymerase chain reaction (PCR). A HPV-related sequence (140 bp) in the E6 transforming region was specifically amplified and detected by gel electrophoresis and by the use of a specific oligonucleotide probe. The PCR could detect 10(5)-10(6) copies per cell (maximum sensitivity). Furthermore, HPV 16, 18 and 33 DNAs were synthesized in a common reaction solution and specifically detected by HPV type-specific probes. The PCR detected the HPV sequence from tissues which were negative to Southern hybridization. This detection technique may contribute significantly to the precise analysis of HPV in small proliferative lesions in the cervix.

Base Sequence↗

PubMed1990

Flowcytometric analysis of DNA pattern of cells derived from xeroderma pigmentosum A--hypersensitivity to vincristine, etoposide and methotrexate.

Xeroderma pigmentosum complementation group A (XPA) is one of the DNA repair deficient syndromes. The cell biological features of XPA were examined by flowcytometry using Epstein Barr (EB) virus-transformed lymphoblastoid cells. Cellular sensitivity to vincristine (VCR), etoposide (VP-16) and methotrexate (MTX) were assayed by DNA pattern changes by flowcytometry. Recently, ataxia-telangiectasia (AT), one of the same kind of disorder, has been reported to have an increased sensitivity to VCR and VP-16. However, AT showed some resistance to MTX according to other reports. Our results showed that XPA had an increased sensitivity to VCR and also to VP-16. Moreover, different from AT, XPA showed some sensitivity to MTX. Thus there is some cell biological similarity between XPA and AT, as well as some difference of the abnormality in the DNA repair pathway.

Cell Line↗

PubMed1990

Enantioselective synthesis of cyclohexenone derivatives by a chemicoenzymatic approach: stereo- and regioselective route to potential intermediates of compactin (ML 236B) and mevinolin.

As a synthetic application of the chiral monoester 2, prepared by pig liver esterase (PLE)-catalyzed hydrolysis of the corresponding meso diester 1, conversion of 2 into various cyclohexenone derivatives was examined. This paper describes the preparation of the isomeric cyclohexenones 6 and 7, potential intermediates for the synthesis of anti-hypercholesmic compactin (ML 236B) and mevinolin, under stereo- and regioselective control.

Chemical Phenomena↗

PubMed1990

Stereotaxic approach to hypothalamic nuclei of the Shiba goat with radiographic monitoring.

Practical method was devised for precise approach to hypothalamic nuclei in the Shiba goat. A stereotaxic instrument and a brain atlas with stereotaxic coordinates were developed. For an accurate placement of probes into specific hypothalamic regions a radiographic method was employed in which radio-opaque material was injected into the lateral ventricle and the ventricular outline was depicted. A sagittal diagram showing the arrangement of hypothalamic nuclei in relation to the brain ventricular system was constructed from the transverse stereotaxic atlas. This diagram was revealed extremely useful in pinpointing the target on the radiographs of lateral view. Precision of this method was evaluated in female Shiba goats (n = 4) by comparing radiographically estimated positions of hypothalamic nuclei with those histologically determined. Despite of cranial variability among individual animals these two parameters matched well each other in all the nuclei examined. Furthermore, chronic cannulae were implanted into different hypothalamic structures of one goat and the accuracy of their placement was confirmed histologically. Thus, it was revealed that the stereotaxy by aid of radiography herein described was accurate enough to apply to various neuroendocrinological studies in the Shiba goat.

Animals↗

PubMed1990

Ultrastructural differentiation in the distal ends of ameloblasts from the presecretory zone to the early secretory zone.

Morphological differentiation of the distal ends of ameloblasts (AMs) from the late presecretory to early secretory zones of the rat upper incisor was studied by electron microscopy. Preameloblasts (PAs) showed a high columnar shape, with the nucleus located in the basal portion. The Golgi apparatus occupied the supranuclear region with type-1 vesicles, and microvilli were present at the distal cell membrane. Coarse-textured material was observed inside the type-1 vesicles and in the lateral intercellular spaces as well as along the distal cell membrane, whereas fine-textured material was found along the distal cell membrane. Near the region of initial enamel formation, large matrix islands were found in the lateral intercellular space. A thin electron-dense layer was observed on the dentin surface. This layer might have occurred as a result of diffusion after degradation of the coarse- or fine-textured material into a finer substance in the extracellular spaces. In the region of initial enamel formation, the distal cell membrane of AMs was flat, but shallow and narrow membrane invaginations were associated with the cell membrane close to the matrix islands. In the region of inner enamel formation, a cone-shaped Tomes' process was formed between large matrix islands which had developed in the intercellular spaces between the lateral portions of the distal ends of AMs. It was considered that the membrane invaginations which had existed at the distal end of PAs moved lower toward the distal terminal bar, thereafter becoming microvilli.

Ameloblasts↗

PubMed1990

A new liver perfusion and preservation system for transplantation research in large animals.

A kidney perfusion machine, model MOX-100 (Waters Instruments, Ltd, Rochester, MN) was modified to allow continuous perfusion of the portal vein and pulsatile perfusion of the hepatic artery of the liver. Additional apparatus consists of a cooling system, a membrane oxygenator, a filter for foreign bodies, and bubble traps. This system not only allows hypothermic perfusion preservation of the liver graft, but furthermore enables investigation of ex vivo simulation of various circulatory circumstances in which physiological perfusion of the liver is studied. We have used this system to evaluate the viability of liver allografts preserved by cold storage. The liver was placed on the perfusion system and perfused with blood with a hematocrit of approximately 20%, and maintained at 37 degrees C for 3 h. The flows of the hepatic artery and portal vein were adjusted to 0.33 mL and 0.67 mL/g of liver tissue, respectively. Parameters of viability consisted of hourly bile output, oxygen consumption, liver enzymes, electrolytes, vascular resistance, and liver histology. This method of liver assessment in large animals will allow the objective evaluation of organ viability for transplantation and thereby improve the outcome of organ transplantation. Furthermore, this pump enables investigation into the pathophysiology of liver ischemia and preservation.

Animals↗

PubMed1990

Ex vivo perfusion for accurate assessment of liver graft viability in dogs.

A new type of ex vivo liver perfusion model (EVPM) was developed. The system includes a physiological porto-portal connection, using a centrifugal pump and an aorto-aortal connection, through a heparin-coated tube. Ten pairs of mongrel dogs, weighing 13-20 kg, were used. Grafts of the liver procured from donors were perfused on the EVPM for 3 h. These grafts were divided into two groups: group A (n = 5), nonpreserved graft; group B (n = 5), 8-h graft preserved with lactated Ringer's solution (4 degrees C). The orthotopic liver transplantation (OLTx) series with the nonpreserved graft was reviewed, and dogs surviving for over 7 days following OLTx, group C (n = 5), were selected for liver grafts in the actual OLTx. In comparison with groups A and C, no difference was noted among enzyme levels (sGOT, sGPT, LDH) or in the recovery rate of ATP content in the graft liver tissue after revascularization. There were significant differences between group A and group B after revascularization. This simple and physiological EVPM accurately reflects graft function and hemodynamics in the actual OLTx. Graft viability, as a substitute for OLTx, in large animals can be reliably assessed. This EVPM is expected to contribute to research on events related to liver transplantation.

Adenosine Triphosphate↗

PubMed1990

Development of an automatic medical summary report system.

We developed a medical summary report system. In this system, each department can specify the predetermined conditions for issuing the summary report. The summary is made through a hierarchical database in the integrated hospital information system according to the predetermined conditions. The summary automatically issued after reception of the outpatient, or also issued by on-line summary report program with the patient number if requested by doctors. The report is sent to the proper consulting room from the reception desk using an air-shooter. The report contains the patient information such as a patient name, age, sex, birthday, a clinic name, a chart number, a patient number, diagnoses and examinations. The doctors can refer to the points of the clinical history of the patient in his own and other departments, and make a correct diagnoses and avoid the overlaps of the examinations and medications. This system has contributed to the quality-up of the patient care by availability of patient information even in other departments without the medical chart.

Hospital Information Systems↗