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Biomedical subjects

T Nishimura

Publications and source records attributed to T Nishimura.

At least 775 records · Page 43Linked to original sources
PubMed1992

Cumulative white matter changes in the gerbil brain under chronic cerebral hypoperfusion.

An animal model of chronic brain hypoperfusion has been developed by applying coiled clips to the bilateral carotid artery of Mongolian gerbils. The brain tissue damage was neuropathologically studied after 1, 4, 8, and 12 weeks of hypoperfusion. The hippocampus, basal ganglia, and cerebral cortex of the chronically hypoperfused gerbil showed lesions with various severity which are probably due to ischemic episodes. In the cerebral white matter, however, two types of lesions were observed; one similar to those in the gray matter, and the other observed only in the white matter after more than an 8-week duration of brain hypoperfusion. The lesion specific to the white matter showed rarefaction and gliosis without locally associated ischemic changes. This type of the white matter lesion was never found in the gerbil brain before 8 weeks and, significantly, increased in number and size by 12 weeks post operation. The accumulation of the white matter lesions is characteristic in the gerbil with chronic hypoperfusion. The observed white matter-specific lesion resembles the histological changes in aged brain with cerebrovascular diseases.

Animals↗
PubMed1992

Sequential change of hemodynamic reserve in patients with major cerebral artery occlusion or severe stenosis.

To identify regional vasodilatory capacity and its sequential change, we evaluated prospectively a total of 78 acetazolamide tests in 51 patients with occlusion or greater than 75% stenosis of the carotid or middle cerebral arteries. The relative distribution of cerebral blood flow was determined by single photon emission computed tomography using N-isopropyl-p-[123I]-iodoamphetamine before and after intravenous injection of acetazolamide. Reduced vasodilatory capacity was demonstrated in 20 patients (38%), including 5 patients with hemodynamic transient ischemic attacks or infarction. Follow-up acetazolamide tests revealed asymptomatic progression of the arterial lesion (from stenosis to occlusion) in 1 patient and almost complete improvement of vasodilatory capacity in 5 patients, including 3 without surgical intervention. During an average follow-up period of 18.5 months, 4 patients died from cardiac causes or neoplasm; no neurovascular events occurred. Much larger numbers of patients with longer observation periods will be necessary to clarify the contribution of chronic hemodynamic failure to subsequent stroke. However, the present data indicate that the acetazolamide test is useful for assessing the course of high grade stenosis or occlusion of major cerebral arteries.

Acetazolamide↗
PubMed1992

Coronary arterial involvement in aortitis syndrome: assessment by exercise thallium scintigraphy.

It is important in patient management to evaluate coronary arterial involvement in aortitis syndrome. Twenty-one cases of aortitis syndrome who experienced chest pain were examined using exercise thallium scintigraphy. The patients were divided into 4 groups according to the angiographic findings. There were five patients with left main coronary arterial involvement (group A), four with left or right coronary arterial involvement (group B), nine with aortic regurgitation (group C), and three with pulmonary arterial involvement (group D). In groups A and B, all patients had positive ECGs and thallium perfusion defects. Group A patients showed extensive anterolateral perfusion defects, which were compatible with left main coronary arterial involvement. Groups C and D patients, who had normal coronary arteries, showed no remarkable perfusion defects although five had positive ECG findings. Thus, the sensitivity and specificity of exercise scintigraphy for detection of myocardial ischemia were 9/9 and 12/12, while those of stress ECG were 9/9 and 7/12 (58%), respectively. it is recommended that exercise thallium scintigraphy be used for detecting clinically occult but significant coronary arterial involvement in aortitis syndrome with chest pain.

Adult↗
PubMed1992

Favorable biodistribution of 99mTc-ECD for brain SPECT comparing with 123I-IMP using alternative body scan.

In order to evaluate the lung and brain uptake of 99mTc ethyl cysteinate dimer (99mTc-ECD) and N-isopropyl-p-[123I]-iodoamphetamine (123I-IMP), alternative body scans were carried out in 15 cases of cerebrovascular disease. The biodistribution of 99mTc-ECD was 5.5 +/- 0.7%, 3.8 +/- 0.7% in the brain; 13.1 +/- 3.7%, 2.2 +/- 1.2%, in the lung at 15 min and at 4 hours, respectively, whereas that of 123I-IMP was 3.9 +/- 1.4%, 5.0 +/- 1.0% in the brain; 32.2 +/- 7.6%, 12.7 +/- 3.3%, in the lung at 15 min and at 4 hours, respectively. 99mTc-ECD accumulated in comparatively high amounts in the brain but remained low in the lung in the early image compared to 123I-IMP. However there was a high inverse correlation between brain and lung uptake of 123I-IMP (r = -0.82), but not of 99mTc-ECD (r = -0.18). We concluded that 99mTc-ECD had a better biodistribution in terms of low lung accumulation than 123I-IMP in brain SPECT.

Aged↗
PubMed1992

Ischemic injury in cirrhotic livers: an experimental study of the temporary arrest of hepatic circulation.

In order to prevent massive bleeding at hepatectomy, the temporary arrest of hepatic circulation is often performed but it is not clear whether this arrest of circulation is tolerated equally by the cirrhotic liver and the normal liver. We investigated biochemically the detailed effects of ischemia on cirrhotic livers in rats with experimentally induced liver cirrhosis. Thioacetoamide was used to prepare the rat cirrhotic liver model (LC group, n = 6). After laparotomy, the vessels to the left lateral lobe were clamped for 30 min and then declamped. Changes in AST isozymes and the aminogram in the blood were examined after ischemia. Postischemic changes in hepatic adenine nucleotides (AdN) and the brain aminogram were also examined. These were compared with those of normal liver ischemia (N group, n = 6) at 24 hr after recirculation. In the LC group, serum levels of mitochondrial AST, a parameter of necrotic cells, were significantly higher than those of the N group. Hepatic AdN levels decreased to 60.6% of the original levels after ischemic injury but those of the N group remained at 95.4% of the original level. Since AdN in tissue is accepted as a reliable parameter of viable cells, cirrhotic livers subjected to ischemia might have more necrotic cells than normal livers. Sequential analysis of serum aminograms of the LC group after ischemia revealed that the ratio of Val+Leu+Ileu/Tyr+Phe decreased to near 1.0 but that of the N group always remained higher than 3.0. Based on these results, it was concluded that ischemic injury in cirrhotic livers is more hazardous than that in normal livers.

Adenosine Triphosphate↗
PubMed1992

Natural cytotoxic T cells responsible for anti-CD3-induced cytotoxicity in mice.

T cells obtained from normal mouse spleen cells showed significant cytotoxic activity against Fc receptor positive tumor cells in the presence of anti-CD3 monoclonal antibody (mAb). This activity was designated as natural cytotoxic T cell (NCT) activity and compared with natural killer (NK) activity. Considerable levels of NCT activity were detected in mouse strains with both high and low NK activity. NCT cells were distributed in both lower and higher density fractions of Percoll discontinuous density gradients, while NK cells were enriched in the lower density fraction of Percoll gradients. Moreover, NCT activity was resistant to in vivo anti-asialo GM1 treatment, in contrast to NK cells. These results indicate that NCT cells, which have different characteristics from NK cells, are present in normal, nonimmunized mouse spleen cells. Unexpectedly, CD4+ T cells sorted from normal mouse spleen T cells revealed significant NCT activity, as did CD8+ T cells. It was also demonstrated that NCT cells require the LFA-1 molecule to lyse tumor cells in the presence of anti-CD3 mAb.

Animals↗
PubMed1992

Perforin is expressed in CTL populations generated in vivo.

Immunization of C57BL/6 mice with syngeneic tumor cells, MBL-2, resulted in the generation of antitumor effector cells in vivo. The immunized C57BL/6 mice permanently rejected viable MBL-2 lymphoma cells, but not B16 melanoma cells. Cytotoxic T cells obtained from MBL-2-immunized mouse peritoneal cells (PEC) showed specific cytotoxicity against MBL-2, but not to YAC-1, RDM-4 and Meth A cells. By sorting with FACStar, the specific CTL were characterized as TCR alpha beta+ CD8+ T cells. Moreover, the cytoplasm of in vivo-induced CTL was stained with a monoclonal antibody against perforin. The localization of perforin in cytoplasmic granules of CTL was demonstrated by electron microscope analysis. This experiment presented the first evidence that in vivo-induced CD8+ CTL against syngeneic tumor cells expressed significant amounts of perforin.

Animals↗
PubMed1992

Change in the cytoskeletal system in fibroblasts from patients with familial Alzheimer's disease.

1. Fibroblasts were cultured from four patients, two patients from two independent family lines, clinically diagnosed as familial Alzheimer's disease. 2. Adhesion efficiency to the dish was significantly suppressed with fibroblasts from patients with familial Alzheimer's disease compared with the cells from the age-matched control. 3. Cytoskeletal systems were visualized by immunofluorescent staining with antibodies against tubulin, actin, and vimentin, showing unique dearrangement of vimentin fibers in fibroblasts from familial Alzheimer's disease. 4. Regrowth of vimentin fibers after colchicine treatment was slower with fibroblasts from familial Alzheimer's disease than that of the control. 5. Western blotting analysis showed no change in tubulin, actin, and vimentin, but the size of fodrin in familial Alzheimer fibroblasts were different from that of the control cell.

Actins↗
PubMed1992

Continuous and simultaneous ultrasound Doppler velocimetry of the internal carotid and vertebral arteries: preliminary observations of cerebral blood flow changes with common carotid compression.

We have developed a new technique for simultaneous assessment of the four cervical cerebral arteries. Using a cervical brace with four freely adjustable Doppler probes attached, we studied four healthy young males and observed their cerebral blood flow changes during common carotid compression. The results indicated various reactivity in these subjects. We observed that carotid compression sometimes affects or stops the ipsilateral vertebral flow according to the intensity and location of compression. Also, the flow of the contralateral internal carotid artery (ICA) and vertebral artery (VA) showed remarkable increases greater than those due to ICA obliteration alone. This indicates the possibility that using only one probe during compression may often result in unknown obliteration of the ipsilateral VAs flow and could also produce other incomplete data. Moreover, with our technique, we would be able to assess the cerebral reserve more precisely and clearly in patients with carotid or vertebral occlusive diseases.

Adult↗
PubMed1992

Purification and properties of aminopeptidase C from porcine skeletal muscle.

1. Aminopeptidase C was purified from porcine skeletal muscle. 2. The mol. wt of the enzyme was found to be 103,000 on both Sephadex G-200 column chromatography and SDS-PAGE. 3. The optimum pH for the hydrolysis of L-leucine p-nitroanilide was around 7.0. 4. The activity of this enzyme was strongly inhibited by EDTA, bestatin and puromycin. 5. The enzyme acted on the beta-naphthylamide derivatives of amino acids and oligopeptides.

Amino Acid Sequence↗
PubMed1992

Evaluation of the susceptibility effect on gradient echo phase images in vivo: a sequential study of intracerebral hematoma.

Susceptibility effect of intracerebral hematoma was estimated on the phase images of gradient echo (GrE). Thirty-five hematomas were studied 3 hr to 5 yr after the onset, a total of 72 times with use of phase and magnitude images of GrE, as well as T1-, T2-, and density-weighted spin-echo (SE) images at 1.5 T. On the basis of the theory of electromagnetism, phase shift to hematoma was calculated for simplified models with concentric distribution of paramagnetic susceptibility. All hematomas were well visualized by the phase images, the pattern of which changed sequentially. The distribution of paramagnetic susceptibility could be estimated by correlating the observed phase shifts with the calculated one. SE images were necessary to presume the type of magnetic substances. A probable hypothesis of the evolution of intracerebral hematoma is proposed.

Adult↗
PubMed1992

Case report: MR appearance of a retained surgical sponge.

A case of a retained surgical sponge found in the retroperitoneum is presented with findings on magnetic resonance (MR) imaging, computed tomography (CT), ultrasonography (US) and angiography. Among all the performed modalities, a characteristic internal structure of the gauze granuloma was best visualized on MR imaging. If no radio-opaque marker is seen on plain radiography or CT, the folded fabric inner structure visualized on T2-weighted images can be a most important clue to the correct diagnosis of this iatrogenic mass.

Female↗
PubMed1992

Large-scale culture system of human CD4+ helper/killer T cells for the application to adoptive tumour immunotherapy.

A simple method for the rapid expansion of human CD4+ T cells with both helper and killer functions was established. CD4+ T cells separated from peripheral blood mononuclear cells using immunomagnetic beads were stimulated with immobilised OKT-3 monoclonal antibody (mAb) plus recombinant interleukin 2 (rIL-2) in 96 well culture plates. After 6 day-culture, the CD4+ T cells were restimulated by immobilised OKT-3 mAb for an additional 24 h, then inoculated into concentrated rotary-tissue culture bag and cultured for further 9 days. This procedure yielded a 3000-fold increase in cell number (about 3-5 x 10(9) per bag). Most of the cells (over 96%) continued to express CD4+ antigen and retained their capacity to produce IL-2. The activated CD4+ T cells showed marked cytotoxicity against Fc receptor positive tumour cells in the presence of OKT-3 mAb. Moreover, we succeeded in a specific targeting of the expanded CD4+ helper/killer T cells to c-erb B-2 positive tumour cells by means of anti-CD3 x anti-c-erb B-2 bispecific antibody. These results suggested that our established simple system will be available for the expansion of large number of CD4+ helper/killer T cells which may provide an efficient strategy for adoptive tumour immunotherapy.

Antibodies, Monoclonal↗
PubMed1992

Guanosine 3',5'-cyclic monophosphate regulates calcium channels in neurones of rabbit vesical pelvic ganglia.

1. The effects of dibutyryl guanosine 3',5'-cyclic monophosphate (db-cyclic GMP) were studied in vitro on calcium channels of neurones in rabbit vesical parasympathetic ganglia, using intracellular and single-electrode voltage-clamp recordings. 2. Db-cyclic GMP (100 microM) caused membrane depolarization associated with a decrease in membrane input resistance and an after-hyperpolarization associated with an increase in membrane input resistance. 3. Db-cyclic GMP (0.01-1 mM) caused a concentration-dependent, transient inward current followed by a long-lasting outward current. Membrane conductance was increased and decreased during the inward and outward currents, respectively. 4. The db-cyclic GMP-induced inward current was depressed in nominally calcium-free solutions, by cobalt (1 mM) and nicardipine (10 microM). The mean reversal potentials of the inward current were +42 and -20 mV in the presence and absence of calcium in the external solution, respectively. 5. The db-cyclic GMP-induced inward current was not altered by lowering the external sodium concentration, raising external potassium concentration or by intracellular injection of caesium. 6. A calcium-insensitive component of the db-cyclic GMP-induced current was increased by lowering the external chloride concentration and blocked by 4-acetamido-4'-isothiocyanostilbene-2,2'-disulphonic acid, a chloride channel blocker. 7. Voltage-dependent, high-threshold calcium currents were depressed during the db-cyclic GMP-induced inward current and facilitated during the outward current. 8. Cyclic GMP was less potent than db-cyclic GMP in causing both inward and outward currents or modulation of calcium currents. GTP, GDP, GMP, guanosine, 8-bromoadenosine 3',5'-cyclic monophosphate and forskolin did not alter the holding current or voltage-dependent calcium currents. 9. It is concluded that intracellular cyclic GMP causes not only activation of resting calcium and chloride channels but also a transient depression followed by long-lasting facilitation of voltage-dependent calcium currents in neurones of vesical parasympathetic ganglia.

Animals↗
PubMed1992

[Mycoplasma pneumoniae respiratory tract infection prevailing among infants at a nursery school].

Mycoplasma pneumoniae (M. pneumoniae) infection in infants had been considered to be very rare, but recently some clinical cases have been reported. We experienced an epidemic of M. pneumoniae infection in a nursery school, and compared M. pneumoniae infection in infants with that in preschool and school children to investigate the features of infantile M. pneumoniae infection. We obtained the following clinical findings in 15 infantile patients with M. pneumoniae infection: The maximum body temperature scarcely increased to 38.5 degrees C or more and the period of high temperature and cough was shorter in infant patients than in preschool and school aged patients. Stridor occurred in 4 patients but skin disorder was not observed. In the laboratory findings, the white blood cell count tended to increase with no changes in neutrophil/lymphocyte ratio and CRP increased slightly. M. pneumoniae antibody was negative in all the patients except 3 and old hemagglutination tests were positive in only 4 patients. The chest X-ray examinations showed a mild increase in the hilar shadow. However, the sequentially located homogeneous shadow which is commonly seen in preschool and school aged patients was not detected. M. pneumoniae antibody scarcely increased in infantile patients but M. pneumoniae was isolated by throat culture from 14 of the 15 patients who were diagnosed as having M. pneumoniae infection.

Child Day Care Centers↗
PubMed1992

Aortic aneurysms: growth rates measured with CT.

Because of a lack of information about the rates of growth of aortic aneurysms, such rates in thoracic and abdominal aortic aneurysms were determined. One hundred seventy-one patients with atherosclerotic aortic aneurysm managed nonoperatively were followed up for more than 6 months with sequential computed tomography (CT). There were 211 aneurysms (thoracic aortic, 82; abdominal aortic, 129). The growth rates of thoracic and abdominal aortic aneurysms were 0.42 and 0.28 cm/y, respectively. Aneurysms at the aortic arch (n = 34) grew at a faster average rate (0.56 cm/y) than aneurysms arising at other levels, even when the rate was corrected for the initial diameter. It is recommended that thoracic aortic aneurysms, especially aortic arch aneurysms, be followed frequently with CT examination of size.

Adult↗
PubMed1992

Assessment of myocardial viability by using newly developed myocardial SPECT imaging.

Thallium myocardial imaging has been widely available for the detection of myocardial ischemia and assessment of myocardial viability in coronary artery diseases. However, myocardial imaging using SPECT and gamma-emitting radiopharmaceuticals has been developed for accurate evaluation of myocardial infarction and ischemia. The present study was undertaken to clinically evaluate myocardial necrosis, metabolism and sympathetic nerve activity. In this study, myocardial fatty acid metabolism was assessed using 123I-BMIPP, myocardial sympathetic neural activity was assessed using 123I-MIBG and myocardial necrosis was assessed using 111-In-antimyosin Fab. Dual energy SPECT using these new agents and thallium gives precise characterization of myocardial viability in coronary artery disease.

3-Iodobenzylguanidine↗