Biomedical subjects

T Shiga

Publications and source records attributed to T Shiga.

At least 73 records · Page 4Linked to original sources

PubMed1998

Thallium-201 scintigraphy to predict therapeutic outcome of iodine-131 therapy of metastatic thyroid carcinoma.

UNLABELLED: We studied the relationship between 201Tl uptake and the efficacy of radioiodine therapy in thyroid carcinoma. METHODS: Forty-four patients with metastases of well-differentiated thyroid carcinoma received 201Tl scintigraphy within the 2 mo before their initial 131I therapy. Patients were classified into two groups according to the tumor-to-background (T/B) ratio on the late 201Tl scan: high 201Tl uptake (T/B > or = 2.1) and low 201Tl uptake (T/B < 2.1). The therapeutic outcome was judged by the percent reduction in the tumor diameter at 6 mo after the treatment. The treatment was defined as effective when the tumor showed more than 50% reduction in the tumor diameter. The patients in whom radioiodine was ineffective were followed up to determine if the tumor showed further growth. RESULTS: Of the 44 patients, 25 had high 201Tl uptake and 19 had low 201Tl uptake. The therapy was effective in 15 patients and was ineffective in 29. All the patients in whom radioiodine was effective had low 201Tl uptake. On the other hand, 25 of 29 patients in whom radioiodine was ineffective had high 201Tl uptake. Eight patients, in whom radioiodine was ineffective despite good 131I uptake, had high 201Tl uptake. There were no significant differences in the positive predictive value and the negative predictive value for effective treatment between 201Tl scintigraphy and therapeutic dose 131I scintigraphy. Among the 25 patients in whom radioiodine was ineffective and who had high 201Tl uptake, the tumor diameter increased in 7 (28%). However, none of the tumors with low 201Tl uptake increased in size during the follow-up period. CONCLUSION: Thallium-201 scintigraphy has a high predictive value for the efficacy of radioiodine therapy in metastatic thyroid carcinoma. Thus, it is helpful in determining the indication for radioiodine therapy and it seems to be an adjunct to tracer dose 131I scintigraphy.

Adenocarcinoma, Follicular↗

PubMed1998

[Transformation of myelofibrosis into acute myelogenous leukemia (M0) with multiple tumor emboli].

A 60-year-old woman was admitted in August 1995 complaining of abdominal pain. A diagnosis of essential thrombocythemia had been made in 1987, and myelofibrosis developed in the patient thereafter. Physical examination revealed massive hepatosplenomegaly, and the peripheral blood showed leukoerythroblastosis with chromosomal abnormalities in peripheral blood cells. In May, 1996, blastic transformation occurred. Based on the findings of surface marker analysis, the blasts met the diagnostic criteria for acete myelogenous leukemia because they were negative for peroxidase and positive for CD13. In June, the patient died of multiple organ failure. Postmortem examination revealed multiple tumor emboli.

Cell Transformation, Neoplastic↗

PubMed1998

[A comparative study of postmortem MR imaging and pathological examination of human brain specimens].

This study was designed to assess the value of MRI of the postmortem brain specimens by comparing MRI findings with neuropathological findings. Postmortem MRI was performed in 17 consecutive formalin-fixed whole brains comprisig 3 with primary CNS neoplasm, 1 with metastatic brain tumor, 6 with cerebral vascular disease (CVD), 1 with degenerative disease, 1 with spongy state in thalamus, and 5 with no abnormality. Postmortem T2WI detected all neuropathological abnormalities but sparsely distributed tumor cells without edema. In one case of CNS neoplasm, the tumor lesions with little necrosis or edema showed isointensity to brain tissue, while others with large amounts of necrosis and edema showed high signal intensity on T2WI. In the cases of CVD, the major signal changes on T2WI were due to edema, necrosis, and damage of the organization as observed on neuropathological studies. There was one case in which both MRI and neuropathological examination showed an abnormality, which was pathologically unexplainable. In two cases, findings of postmortem MRI were more apparent than those of macroscopic examination. Postmortem MRI appeared different from premortem MRI in one of the rest three cases whereas the postmortem MRI correlated well with neuropathological findings. Progression of the disease immediately before death may have caused this difference. In conclusion, the correlations between MRI and neuropathological findings facilitate understanding the mechanisms responsible for MRI abnormalities. An increase in free water in edema, necrosis, and damage in brain tissue can explain an increased signal intensity on T2WI. Postmortem MRI may contribute to the effective pathological examination by pointing out subtle abnormalities before brain cutting.

Aged↗

PubMed1997

Cell adhesion molecules regulate guidance of dorsal root ganglion axons in the marginal zone and their invasion into the mantle layer of embryonic spinal cord.

In order to elucidate the mechanisms regulating the projections of dorsal root ganglion (DRG) axons in the dorsal funiculus and invasion into target regions in the mantle layer (prospective gray matter) of the spinal cord, we examined the interactions between DRG axons and spinal cord. DRG neurons were dissociated from chick embryos and cultured for 1-2 days on cryostat sections of the spinal cord at embryonic day 5 (E5) or at E9. E5 and E9 DRG neurons extended neurites onto both marginal zone (prospective white matter) and mantle layer (prospective gray matter) of the spinal cord, suggesting that both of these regions are permissive for neurite growth. When E5 DRG neurites approached cryosections of E5 spinal cord from outside, most of them ran in the marginal zone without invading the mantle layer. In contrast, about half of E9 DRG neurites entered the mantle layer after crossing the marginal zone of E9 spinal cord. These growth patterns of DRG neurites on spinal marginal zone and mantle layer are similar to the pathway formation of DRG axons at comparable stages in vivo; DRG axons run exclusively in the prospective dorsal funiculus before E6, and enter the mantle layer (prospective dorsal horn) to reach the target regions by E9. Perturbation of functions of Ng-CAM, Nr-CAM, and axonin-1/SC2 by adding the specific antibodies in the culture medium increased the ratio of DRG neurites entering the mantle layer of E5 spinal cord, suggesting that these cell adhesion molecules are involved in keeping DRG neurites in the marginal zone. Taken together with the expression of Ng-CAM, Nr-CAM, and axonin-1/SC2, these CAMs on DRG axons may regulate the guidance of these axons in the marginal zone before E6, and the subsequent decrease in the relative levels of these CAMs might allow DRG axons to invade the target mantle layer.

Animals↗

PubMed1997

Role of nitric oxide in oxygen transport in rat liver sinusoids during endotoxemia.

To evaluate the role of nitric oxide (NO) in hepatic microcirculation and liver injury during endotoxemia, we studied O2 transport in the hepatic microcirculation of endotoxin-infused rats. Rats were continuously infused with Escherichia coli lipopolysaccharide (LPS) (0.8 mg/kg/h) for 7 hours. LPS increased the plasma levels of NO2- + NO3- and aspartate transaminase (AST), and decreased the bile flow rate and hepatic adenosine triphosphate (ATP) level. Hepatic microcirculation was evaluated by two methods: reflectance spectrophotometry showed a decrease in the oxygenation of hemoglobin (Hb) in the liver, and dual-spot microspectroscopy indicated that LPS administration decreased blood velocity, the oxygenation of Hb, and O2 release from sinusoids to hepatocytes. The observed decreases in the O2 transport parameters were prominent in pericentral sinusoids. All of these phenomena were further aggravated by the administration of N(w)-nitro-L-arginine methyl ester (L-NAME) (5 mg/kg/h) plus LPS, and by aminoguanidine (AMG) (5 mg/kg/h) plus LPS, and these could be reversed by the concomitant administration of L-arginine (L-Arg) (100 mg/kg/h). These results suggest that deterioration of hepatic oxygen transport and liver function induced by endotoxin can be ameliorated by NO.

Adenosine Triphosphate↗

PubMed1997

Rare complication after stellate ganglion block.

Explore the source record for details and available documents.

Autonomic Nerve Block↗

PubMed1997

Sequential change of BMIPP uptake with age in spontaneously hypertensive rat model.

UNLABELLED: Changes in myocardial perfusion and metabolism are often associated with myocardial hypertrophy, but there are few reports describing the serial assessment of fatty acid metabolism in hypertrophic myocardium. The aim of this study is to assess fatty acid metabolism serially in hypertrophic myocardium in spontaneously hypertensive rats (SHR) with 125I-BMIPP, a branched fatty acid analog. METHODS: SHR and Wistar-Kyoto rats (WKY) as the control were divided into 4 groups (12, 15, 18 and 51 weeks after birth). The heart was extracted 10 minutes after intravenous injection of 125I-BMIPP and 201Tl at the same time. The accumulation of each radiotracer in the myocardium was counted with a well gamma counter. In addition, 125I-BMIPP uptake was corrected by 201Tl uptake (B/T). RESULTS: The heart weight/body weight ratio was significantly higher in SHR than that in WKY (p < 0.001). In SHR, this ratio increased up to 18 weeks (12 weeks; 0.266 +/- 0.005, 18 weeks; 0.281 +/- 0.006: mean +/- SE, p < 0.05). The 125I-BMIPP uptake tended to be significantly reduced in SHR (12 weeks; 2.373 +/- 0.212, 18 weeks; 1.380 +/- 0.047; mean +/- SE, p < 0.05). Such a difference in BMIPP uptake was more evident when BMIPP uptake was corrected by Tl uptake (B/T), but no regional difference or heterogeneity of BMIPP distribution was observed in the hypertrophic myocardium in SHR. CONCLUSION: A change in fatty acid metabolism with age was observed in association with myocardial hypetrophy in this hypertensive rat model, which was well demonstrated with 125I-BMIPP and 201Tl.

Aging↗

PubMed1997

Incidence and clinical significance of linear defects ascribed to interrenuncular septa on 99Tcm-DMSA SPET.

99Tcm-dimercaptosuccinic acid (99Tcm-DMSA) planar and single photon emission tomographic images from 100 children were reviewed to analyse whether linear defects corresponding to anatomical characteristics of interrenuncular septum (IRS) could be seen. Thirty sites in 30 kidneys (20 right, 10 left) from 27 patients were determined as showing IRS. They were seen less frequently in patients less than 7 years of age. The prevalence of IRS in the patients with vesico-ureteric reflux (VUR) was not significantly different from that in the patients without VUR. The interrenuncular septum was never seen on planar images and was most clearly demonstrated on conventional coronal tomographic images. The linear defects ascribed to IRS on 99Tcm-DMSA scintigrams were of a similar incidence to that reported previously. However, IRS is still an unestablished structure, and there is no evidence that these linear defects actually correspond to the structure described as the interrenuncular septum.

Child↗

PubMed1997

Automatic extraction and measurement of leukocyte motion in microvessels using spatiotemporal image analysis.

This paper describes a computer vision system for the automatic extraction and velocity measurement of moving leukocytes that adhere to microvessel walls from a sequence of images. The motion of these leukocytes can be visualized as motion along the wall contours. We use the constraint that the leukocytes move along the vessel wall contours to generate a spatiotemporal image, and the leukocyte motion is then extracted using the methods of spatiotemporal image analysis. The generated spatiotemporal image is processed by a special-purpose orientation-selective filter and a subsequent grouping process newly developed for this application. The orientation-selective filter is designed by considering the particular properties of the spatiotemporal image in this application in order to enhance only the traces of leukocytes. In the subsequent grouping process, leukocyte trace segments are selected and grouped among all the segments obtained by simple thresholding and skeletonizing operations. We show experimentally that the proposed method can stably extract leukocyte motion.

Algorithms↗

PubMed1997

Normal human fibroblasts immortalized by introduction of human papillomavirus type 16 (HPV-16) E6-E7 genes.

This report demonstrates that normal human fibroblasts can be immortalized by the introduction of HPV-16 E6-E7 genes. We designed zinc-inducible expression plasmids with HPV-16 E6, E7 or both. Each plasmid was introduced into normal human fibroblasts (TIG-3 cells) using lipofection methods. Only transfectants with the HPV-16 E6-E7 zinc-inducible expression plasmid, which were cultured in medium supplemented with 100 microM ZnSO4, overcame crisis and could be cultured over 200 population doubling levels (PDLs). These cell lines showed the reactivation of telomerase after crisis, and morphological alterations were also observed.

Cell Culture Techniques↗

PubMed1996

Hypothermia suppresses nitric oxide elevation during reperfusion after focal cerebral ischemia in rats.

We aimed to investigate effect of temperature on the jugular levels of nitric oxide (NO) at reperfusion after focal cerebral ischemia. Both nitrosyl hemoglobin (HbNO) (2.5 +/- 0.4 microM) and plasma nitrite plus nitrate levels (61 +/- 5 microM) in rats under normothermia (approximately 37 degrees C) after 30 min of reperfusion following 2 h of left middle cerebral artery occlusion were significantly high, compared with sham operated rats (1.3 +/- 0.1 microM, 40 +/- 4 microM, respectively). Both HbNO (1.5 +/- 0.3 microM) and nitrite plus nitrate levels (43 +/- 7 microM) under moderate hypothermia (approximately 32 degrees C) were significantly low, compared with normothermic rats. HbNO (2.8 +/- 0.8 microM) and nitrite plus nitrate levels (65 +/- 8 microM) under mild hyperthermia (approximately 39 degrees C) were not significantly high. These results firstly demonstrated that hypothermia suppresses the elevation in intrajugular NO after cerebral ischemia-reperfusion.

Animals↗

PubMed1996

Characterization of a promoter in the E7 open reading frame of human papillomavirus type 11.

A human papillomavirus type 11 (HPV-11) early gene promoter, PE1--E4, in the E7 open reading frame and involved in the transcription of E1--E4 and E1--E4, L1 mRNAs was characterized by chloramphenicol acetyl transferase (CAT) assay, gel-shift assay, in vitro transcription, and primer extension. By CAT assay with CAT-expression plasmids containing various portions of the HPV-11 genome from nucleotide position (nt) 235 to nt 743, we identified a 112-basepair (bp) sequence (nt 632-743) that had high promoter activity and a 188-bp upstream sequence from nt 395 to nt 572 that strongly suppressed activity. The 112-bp sequence contained a 7-bp repeat (7-bp Rep) with high homology to the Sp1-binding motif (BM) in the E6 promoter of HPV-11 but lacked an identifiable TATA-box. A cellular protein other than Sp1 bound to the 7-bp Rep. Removal of a 21-bp segment (nt 632-652) containing the 7-bp Rep significantly reduced activity. By in vitro transcription assay and primer extension, one of the transcription start sites was mapped to near nt 719. These results suggested that a cellular protein that binds to the 7-bp Rep may act as an activator for PE1--E4.

DNA-Binding Proteins↗

PubMed1996

Pharmacokinetics of a new thromboxane A2 receptor antagonist, S-1452, and its effect on platelet aggregation in healthy volunteers.

To study the pharmacokinetics of a new thromboxane A2 (TXA2) receptor antagonist, S-1452, eight healthy volunteers were given placebo or S-1452 orally on four occasions in step-wise increasing doses of 10 mg, 25 mg, and 50 mg separated by 2-week intervals. Blood samples for measurement of plasma concentrations of the drug and of its inhibitory effect on platelet aggregation were obtained for 24 hours after administration. Bleeding time after administration was measured. S-1452 was rapidly absorbed, with a peak plasma concentration at 30 minutes after administration. Thereafter, the drug was rapidly eliminated (elimination half-life, 0.4-0.5 hours), and no drug was detected at 6 hours. The inhibitory effect of S-1452 on platelet aggregation, which was stimulated by the TXA2 receptor agonist U-46619, persisted more than 6 hours after drug administration. Bleeding time was slightly prolonged after a single dose of S-1452. These results suggest that although S-1452 is rapidly eliminated in plasma, its inhibitory effects on platelet aggregation persist for a longer period. Careful observations are needed to prevent potential bleeding episodes during repeated treatment with the drug.

Administration, Oral↗

PubMed1996

Effect of hypothermia on skeletal muscle metabolism in perfused rat hindlimb.

Temperature-induced metabolic change was studied with isolated rat hindlimb muscle to elucidate how tissue viability is maintained under hypothermia. The hindlimb was perfused with Krebs-bicarbonate buffer containing 4% (w/v) polyvinylpyrrolidone (PVP-40T) in a flowthrough mode at 35-8 degrees C. When the temperature was lowered, the following results were observed: (i) Vascular resistance (defined as perfusion pressure divided by flow rate) increased proportionally with elevation of the viscosity of the perfused medium, suggesting that the capillary bed in the perfused muscle is maintained under a similar condition under these temperatures; (ii) the Arrhenius plot of the O2 uptake rate showed a break at ca. 20 degrees C; (iii) the rates of O2 uptake and lactate release decreased, but the lactate/pyruvate ratio increased even under aerobic conditions; (iv) oxygenation of myoglobin and oxidation of cytochromes increased, suggesting a reduced electron-transfer rate in spite of improved or sufficient oxygenation of the tissue. Based on these results, we concluded that oxidative phosphorylation is more affected by temperature than glycolysis, and thus under hypothermia, the role of glycolysis in energy production increases in rat skeletal muscle, especially below 20 degrees C.

Adenosine Triphosphate↗

PubMed1996

Lipid peroxidation and antioxidant activities in regenerating liver after partial hepatectomy in splenectomized rats.

Lipid peroxidation, antioxidant activities, and total fatty acids were investigated in the regenerating liver after partial hepatectomy in splenectomized male Wistar rats. The lipoperoxide levels were significantly lower in the splenectomized rats than in the non-splenectomized rats. The hepatic superoxide dismutase (SOD) activity was significantly higher in the splenectomized rats than in the controls, whereas the alpha-tocopherol content, and the activities of glutathione (GSH) peroxidase and catalase did not differ so widely between splenectomized and nonsplenectomized rats. In both groups, the fatty acid composition of the total lipids was not so different in the early stages of hepatic regeneration after partial hepatectomy, but it was noted that in the later stages of hepatic regeneration, polyunsaturated fatty acids tended to increase in the splenectomized rats. These results suggest that splenectomy attenuates lipid peroxidation, and tends to increase in polyunsaturated fatty acids in the remnant liver after partial hepatectomy, which may be attributable to high SOD activity, the maintenance of alpha-tocopherol, and the remaining activities of GSH peroxidase and catalase.

Animals↗

PubMed1996

Change in plasma endotoxin titres and endotoxin neutralizing activity in the perioperative period.

PURPOSE: To elucidate whether endotoxaemia detected during major surgery was a specific or non-specific reaction. METHODS: Prospective clinical study in the operating theatre and multidisciplinary intensive care unit in a university hospital. A series of plasma samples was obtained from 21 patients, including eight after cardiopulmonary bypass (CPB), until 48 hr after surgery. The endotoxin titres in these samples were compared by the two chromogenic limulus amebocyte lysate (LAL) assays; one is factor G containing and the other factor G-free, endotoxin-specific test. The endotoxin neutralizing activity of the plasma was determined by adding the endotoxin to the plasma (1,000 pg.ml-1), and by assaying how much the potency of the endotoxin to activate LAL was lost during incubation for 120 min at 37 degrees C. RESULTS: Although endotoxin titres measured using the test including factor G showed a marked elevation during and after surgery, which were 3 +/- 5 (4 +/- 10), 14 +/- 13 (20 +/- 17**), 133 +/- 13* (46 +/- 29*), 89 +/- 72* (48 +/- 35*), 62 +/- 40** (37 +/- 29*), 50 +/- 54 (39 +/- 36) pg.ml-1 in patients with CPB (without CPB), mean +/- SD, at 0, 3, 6, 9, 24, and 48 hr after start of surgery (*P < 0.01, **P < 0.05 compared with 0 hr), those measured by the endotoxin-specific test did not show any changes. Plasma neutralized 95% of endotoxin potency after five minutes incubation at 37 degrees C. CONCLUSION: Using an endotoxin-specific assay, endotoxin could not be detected in the blood stream during or after major surgery.

Adult↗

PubMed1996

Clinical application of the computer picture archiving and communicating system to stereotactic radiosurgery.

Stereotactic radiosurgery, a rapidly evolving technology, provides precise high-dose irradiation to brain lesions and tumors. A new method using digital subtraction angiographic images of a personal computer-image display terminal interfaced to our picture archiving and communication system (PACS) performs measurements and calculations of the coordinates of the location of the center of the lesion to be treated. The time required to calculate the coordinates was performed by three methods: hand calculation, digitizer method, and PACS method. These three coordinates were compared in 10 cases. The hand calculation method required approximately 50 minutes, the digitizer method required approximately 10 minutes, and the PACS method approximately 3 minutes. The difference is statistically significant (P < .001). The three methods were equally accurate. This type of PACS application using inexpensive personal computers interfaced more directly to a PACS is an emerging trend that facilitates wider access to images and to manipulating them for specialized applications.

Humans↗

PubMed1996

Effect of food intake on pharmacokinetics and effects of a new thromboxane A2 receptor antagonist, S-1452.

OBJECTIVE: To examine the effect of food ingestion on the pharmacokinetics of a new thromboxane A2 (TXA2) receptor antagonist, S-1452, and the inhibitory effect on platelet aggregation. METHODS: Fifty milligrams of S-1452 was given orally to eight healthy subjects with or without food. Blood samples for determinations of plasma drug concentrations and of its effects on platelet aggregation were taken for a 12-h post-drug period. RESULTS: The maximum plasma concentration of S-1452 was reduced by 47% and the time to maximum concentration was prolonged from 0.5 to 1.9 h after dosing with food. The inhibitory effect of S-1452 on platelet aggregations induced by U-46619, a TXA2 receptor agonist, and collagen persisted up to 9 h after dosing with and without food. The degrees of inhibition in the two trials did not differ significantly at any point. CONCLUSION: These results suggest that although the absorption of S-1452 is delayed and, consequently, its plasma concentration is decreased after dosing with food, the inhibitory effect on platelet aggregation is not significantly influenced after 50 mg of the drug.

15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5↗