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Biomedical subjects

S Kusano

Publications and source records attributed to S Kusano.

At least 73 records · Page 4Linked to original sources

Age-dependent decline in parenchymal perfusion in the normal human pancreas: measurement by dynamic computed tomography.

Parenchymal perfusion of the normal human pancreas using dynamic computed tomography (CT) was evaluated and correlated with patient demographic characteristics. The results of 23 patients (10 men and 13 women; age range, 25-71 years) who underwent enhanced CT of the upper abdomen and perfusion measurement were retrospectively reviewed. They had no evidence of pancreatic disease or diffuse liver disease, clinically or radiographically. Regions of interest were drawn in the pancreatic body and within the aorta. Pancreatic parenchymal perfusion per volume was then calculated by dividing the peak gradient of the pancreatic time-attenuation curve by the peak aortic CT number in increase. Perfusion in these patients ranged from 0.554 to 1.698 ml min(-1) ml(-1) (mean +/- SD, 0.963 +/- 0.064) and showed a negative correlation with the patient's age (r = 0.699, p < 0.0005). Pancreatic parenchymal density before contrast material injection (mean +/- SD, 48.86 +/- 0.978) was not correlated with perfusion measured by dynamic CT or age. No differences were observed in perfusion or density between men and women. In conclusion, parenchymal perfusion of the normal human pancreas measured by dynamic CT appears to decline with age.

Adult↗

Evaluation of portal pressure by splenic perfusion measurement using dynamic CT.

OBJECTIVE: The purposes of this study were to determine if splenic perfusion measurements obtained using dynamic CT are useful in the evaluation of portal hypertension. MATERIALS AND METHODS: Forty-four patients with chronic liver disease (29 men and 15 women, 49-81 years old) and 38 control subjects (17 men and 21 women, 21-79 years old) underwent dynamic CT of the spleen. Regions of interest were drawn on images of the spleen and aorta, and splenic perfusion was calculated by dividing the peak gradient of the splenic time-attenuation curve by the peak aortic CT measurement increase. In 11 patients with chronic liver disease and three patients with normal livers, we measured the wedged hepatic vein pressure (WHVP) of the right or right accessory hepatic vein to estimate portal vein pressure. RESULTS: Splenic perfusion was less in patients with chronic liver disease (0.894 +/- 0.324 ml/min) than in the control group (1.299 +/- 0.429 ml/min; p < .0001). We found a significant negative correlation between splenic perfusion and WHVP (r = .741; p = .0024). CONCLUSION: A significant decrease in splenic perfusion in patients with chronic liver disease negatively correlated with WHVP. Measurement of splenic perfusion may be useful in the evaluation of portal hypertension.

Aged↗

[Decision tree sensitivity analysis for cost-effectiveness of chest FDG-PET in patients with a pulmonary tumor (non-small cell carcinoma)].

Decision tree analysis was used to assess cost-effectiveness of chest FDG-PET in patients with a pulmonary tumor (non-small cell carcinoma, < or = Stage IIIB), based on the data of the current decision tree. Decision tree models were constructed with two competing strategies (CT alone and CT plus chest FDG-PET) in 1,000 patient population with 71.4% prevalence. Baselines of FDG-PET sensitivity and specificity on detection of lung cancer and lymph node metastasis, and mortality and life expectancy were available from references. Chest CT plus chest FDG-PET strategy increased a total cost by 10.5% when a chest FDG-PET study costs 0.1 million yen, since it increased the number of mediastinoscopy and curative thoracotomy despite reducing the number of bronchofiberscopy to half. However, the strategy resulted in a remarkable increase by 115 patients with curable thoracotomy and decrease by 51 patients with non-curable thoracotomy. In addition, an average life expectancy increased by 0.607 year/patient, which means increase in medical cost is approximately 218,080 yen/year/patient when a chest FDG-PET study costs 0.1 million yen. In conclusion, chest CT plus chest FDG-PET strategy might not be cost-effective in Japan, but we are convinced that the strategy is useful in cost-benefit analysis.

Adult↗

[Reassessment of a combination of cerebrospinal fluid scintigraphy and nasal pledget counts in patients with suspected rhinorrhea].

A combination study of cerebrospinal fluid scintigraphy and nasal pledget counts was performed using 37 MBq of 111In-DTPA in 12 patients with suspected rhinorrhea. A pledget was inserted and dwelled in each nasal cavity for 6 hours, with the patient prone during at least 30 minutes. A total of 18 studies was implemented and nasal pledget counting method successfully diagnosed all of CSF rhinorrhea. Diagnosis was possible when pledget counts were greater than 1 kcpm. In patients with persistent, intermittent and occult/no nasal discharge, rhinorrhea was found in 100% (5/5), 60% (3/5), 25% (2/8), respectively. Two cases only exhibited positive scintigraphy. MRI or CT cisternography should be first performed in patients with persistent discharge, but in patients with intermittent/occult discharge pledget counting method might take priority of other diagnostic modalities. In conclusion, nasal pledget counting method is a simple and useful tool for detecting rhinorrhea.

Adolescent↗

Functional interaction of Escherichia coli RNA polymerase with inorganic polyphosphate.

BACKGROUND: RNA polymerase from the stationary growth phase cells of Escherichia coli is tightly associated with an acidic compound(s) and exhibits altered promoter selectivity, with reduced transcriptional activity of the genes highly expressed in the exponentially growing cells. Here we have examined the nature of the RNA polymerase-associated acidic compound(s). RESULTS: RNA polymerase isolated from stationary-phase cells of E. coli was found to be tightly associated with inorganic polyphosphates (poly P), and cannot be dissociated even after chromatography on phosphocellulose or DNA-cellulose columns. Since RNA polymerase-poly P complexes reconstituted in vitro showed similar properties, poly P was not binding covalently. The inhibitory effects of poly P on transcription were examined using two forms of the holoenzyme, one containing sigma70, the major sigma for transcription of the genes expressed during exponential cell growth and the other containing sigma38, the principal sigma in the stationary growth phase. At low salt concentrations, poly P inhibited transcription by both Esigma70 and Esigma38 holoenzymes. With an increase in the concentration of potassium glutamate, the poly P inhibition was relieved. At high salt concentrations, the Esigma70 holoenzyme is not able to function, but the Esigma38 holoenzyme is however activated. CONCLUSIONS: These results show that poly P may play a role in the promoter selectivity control of RNA polymerase in E. coli which is growing under conditions of high osmolarity and in the stationary growth phase.

Chromatography↗

Rim enhancement in colorectal metastases at CT during infusion hepatic arteriography. Does it represent liver parenchyma or live tumor cell zone?

PURPOSE: To evaluate the morphologic substrate of the rim enhancement of of colorectal metastases seen at CT during infusion hepatic arteriography (CTIHA). MATERIAL AND METHODS: Eleven sector defects in the enhancing rim of 9 metastases at CTIHA were analyzed. The corresponding pathologic specimens were investigated for sector defects of liver parenchyma. We investigated whether there was a correlation between the central angle of the sector defects of rim enhancement at CTIHA and that of sector defects in the zone of liver parenchyma in histologic slices. The inner and outer diameters of the enhancing rim were also compared with the diameter of the metastases as seen at CT during arterial portography (CTAP). RESULTS: There was a significant correlation between the central angle of sector defects of rim enhancement at CTIHA and the angle of sector defects in the zone of liver parenchyma in histologic slices (p = 0.008, Spearman's test). The diameter of the metastases measured at CTAP was larger than the inner diameter and smaller than the outer diamter of the enhancing rim in CTIHA, i.e. the margins of the nodules as seen in CTAP are located in liver parenchyma and not in tumor tissue. CONCLUSION: The morphologic substrate of the rim enhancement of colorectal metastases seen at CTIHA is liver parenchyma.

Adult↗

Enhanced depressor effect of centrally administered high-calcium solution in salt-loaded experimental hypertension.

The depressor effect by oral calcium supplementation is known to be more pronounced in salt-dependent than in renin-dependent hypertension. This study was conducted to investigate the role of central calcium on two different pathophysiologic subtypes of experimental hypertension; (a) salt-dependent, deoxycorticosterone acetate-salt hypertensive rats (DOCA), and (b) renin-dependent, 2-kidney, 1 clip (2-K, 1C) hypertensive rats. In DOCA (n = 10), high-calcium solution (Ca+2, 65.2 mM, 10 microl) given centrally (i.c.v.) elicited a marked decrease in mean blood pressure (MBP; 170 +/- 4 to 138 +/- 5 mm Hg, p < 0.01) with a decrease in heart rate (HR; 390 +/- 18 to 344 +/- 17 beats/min, p < 0.05) lasting for 40 min. In 2-K, 1C (n = 10), high-Ca2+ i.c.v. showed a lesser decrease in MBP (178 +/- 4 to 171 +/- 5 mm Hg) and HR (419 +/- 10 to 395 +/- 12 beats/min) with shorter duration (for 20 min) than in DOCA. This significant depressor and bradycardic response to Ca2+ i.c.v. observed in DOCA was dose dependent at Ca2+ concentrations between 65.2 and 130.4 mM. In DOCA, high Ca2+ i.c.v. reduced the plasma noradrenaline (Nad) concentration significantly (479 +/- 81 to 319 +/- 62 pg/ml, p < 0.05). These results suggest that central Ca2+ plays a more important role in regulating sympathetic nerve activity and BP in salt-dependent than in renin-dependent experimental hypertension.

Animals↗

Stimulatory effect of trehalose on formation and activity of Escherichia coli RNA polymerase E sigma38 holoenzyme.

The intracellular concentration of trehalose increases in the stationary-phase cells of Escherichia coli. The effects of trehalose on transcription in vitro by E. coli RNA polymerase were compared for two holoenzymes, E sigma70 and E sigma38, which were reconstituted from purified core enzyme and either sigma70 (the major sigma at the exponential growth phase) or sigma38 (the essential sigma at the stationary growth phase), respectively. The optimum trehalose concentration giving maximum transcription by E sigma38 was higher than that by E sigma70. Transcription activation by trehalose was attributed to both increased formation of E sigma38 holoenzyme and increased transcription initiation by E sigma38 from sigma38-dependent promoters. The activation of E sigma38 by trehalose was additive with the transcription enhancement by decreased superhelicity of template DNA prepared from stationary-phase cells. We thus propose that the selective activation of transcription by E sigma38 holoenzyme takes place in the presence of specific conditions and factors present under stress conditions.

Coenzymes↗

Promoter selectivity of Escherichia coli RNA polymerase sigmaF holoenzyme involved in transcription of flagellar and chemotaxis genes.

The rpoF gene of Escherichia coli codes for the RNA polymerase sigmaF (or sigma28) subunit, which is involved in transcription of the flagellar and chemotaxis genes. Both sigmaF and sigma70 (the major sigma subunit in growing cells) were overexpressed, purified to homogeneity, and compared with respect to activity and specificity. The affinity of sigmaF to core RNA polymerase (E) is higher than that of sigma70, as measured by gel filtration high-pressure liquid chromatography. In an in vitro transcription system, the holoenzyme (E sigmaF) containing sigmaF selectively transcribed the flagellar and chemotaxis genes, all of which could not be transcribed by E sigma70. This strict promoter recognition property of sigmaF is similar to those of other stress response minor sigma subunits but different from those of the principal sigma subunits, sigma70 and sigma38. sigma70-dependent transcription in vitro is inhibited at high concentrations of all salts tested, showing maximum activity at 50 mM. In contrast, sigmaF-dependent transcription was maximum at 50 mM KCI and then decreased to negligible level at 300 mM; in the cases of potassium acetate and potassium glutamate, maximum transcription was between 200 and 300 mM. DNase I foot printing of the fliC and fliD promoters indicated that sigmaF alone is unable to bind DNA, but E sigmaF specifically recognizes -10 and -35 regions of the sigmaF-dependent promoters with rather long upstream protection. Alteration of the promoter structure after binding of E sigmaF was suggested.

Bacterial Proteins↗

Relation of abdominal and thigh adipose tissue distribution to serum lipids and glucose metabolism in obese males.

Spin-echo magnetic resonance imaging (MRI) and postprocessing for fat quantification were used to examine the relationship of abdominal and thigh adipose-tissue distribution to serum lipids and glucose metabolism in obesity. Thirteen simple obese male patients and 12 non-obese male volunteers were examined by MRI, blood pressure, and fasting blood sample levels of serum lipids, glucose, immunoreactive insulin, c-peptide, HbA1C and hematocrit. Correlations of thigh visceral and subcutaneous fat areas to serum lipid levels were generally similar, but marked differences were found between relationships of thigh versus abdominal fat areas to serum lipid levels. In addition, diastolic blood pressure was significantly correlated with the fat area, especially with the abdominal visceral fat area (r=0.51, p<0.01), but not with abdominal subcutaneous fat area. The thigh muscle area was highly and inversely correlated with c-peptide (r=-0.72, p<0.01) and systolic blood pressure (r=-0.65). Differences in correlations between visceral and subcutaneous fat areas in the abdomen to metabolic parameters were found between abdominal visceral fat areas and HbA1C and between the abdominal subcutaneous fat areas and HbA1C. These findings suggest that the character of regional fat could be heterogeneous with respect to lipid and glucose metabolism and blood pressure levels in obese males.

Abdomen↗

[Successful TSH suppression therapy with triiodothyronine in a patient with pulmonary metastases from differentiated thyroid carcinoma in the absence of 131I uptake].

A 28-year-old woman was referred to us to undergo 131I therapy who had multiple pulmonary metastases from papillary thyroid carcinoma after total thyroidectomy. There was no increased accumulation of a tracer in the pulmonary metastatic foci on whole-body scanning using a 111 MBq diagnostic dose of 131I. However, the pulmonary metastases were gradually decreased in size, and then clearly reduced 8 months after the start of TSH suppression therapy, which was maintained by T3 instead of T4 to bring down the serum TSH level below 0.1 microU/ml. Reduction rates of the foci were 33-76% on chest X-ray. The reduction was confirmed and no new lesions were found on the serial CT scans. Serum thyroglobulin level was lowered 80 to 25 ng/ml by this suppression therapy and progression of disease was not observed under a 54 months' T3 treatment. Thus, TSH suppression therapy might improve survival of patients with differentiated thyroid cancer.

Adult↗

A dual computed tomography linear accelerator unit for stereotactic radiation therapy: a new approach without cranially fixated stereotactic frames.

PURPOSE: To perform stereotactic radiation therapy (SRT) without cranially fixated stereotactic frames, we developed a dual computed tomography (CT) linear accelerator (linac) treatment unit. METHODS AND MATERIALS: This unit is composed of a linac, CT, and motorized table. The linac and CT are set up at opposite ends of the table, which is suitable for both machines. The gantry axis of the linac is coaxial with that of the CT scanner. Thus, the center of the target detected with the CT can be matched easily with the gantry axis of the linac by rotating the table. Positioning is confirmed with the CT for each treatment session. Positioning and treatment errors with this unit were examined by phantom studies. Between August and December 1994, 8 patients with 11 lesions of primary or metastatic brain tumors received SRT with this unit. All lesions were treated with 24 Gy in three fractions to 30 Gy in 10 fractions to the 80% isodose line, with or without conventional external beam radiation therapy. RESULTS: Phantom studies revealed that treatment errors with this unit were within 1 mm after careful positioning. The position was easily maintained using two tiny metallic balls as vertical and horizontal marks. Motion of patients was negligible using a conventional heat-flexible head mold and dental impression. The overall time for a multiple noncoplanar arcs treatment for a single isocenter was less than 1 h on the initial treatment day and usually less than 20 min on subsequent days. Treatment was outpatient-based and well tolerated with no acute toxicities. Satisfactory responses have been documented. CONCLUSION: Using this treatment unit, multiple fractionated SRT is performed easily and precisely without cranially fixated stereotactic frames.

Brain Neoplasms↗

Promoter selectivity of Escherichia coli RNA polymerase E sigma 70 and E sigma 38 holoenzymes. Effect of DNA supercoiling.

The functional specificity was compared between two sigma factors, sigma 70 (the major sigma at exponentially growing phase) and sigma 38 (the essential sigma at stationary growth phase), of Escherichia coli RNA polymerase. The core enzyme binding affinity of sigma 38 was less than half the level of sigma 70 as measured by gel filtration column chromatography or by titrating the concentration of sigma required for the maximum transcription in the presence of a fixed amount of core enzyme. In addition, the holoenzyme concentration required for the maximum transcription of a fixed amount of templates was higher for E sigma 38 than E sigma 70. The transcription by E sigma 38 was, however, enhanced with the use of templates with low superhelical density, in good agreement with the decrease in DNA superhelicity in the stationary growth phase. We thus propose that the selective transcription of stationary-specific genes by E sigma 38 holoenzyme requires either a specific reaction condition(s) or a specific factor(s) such as template DNA with low superhelical density.

DNA, Superhelical↗

Mild resistance to thyroid hormone with a truncated thyroid hormone receptor beta.

Recent studies have revealed mutations in the thyroid hormone receptor beta (TR beta) gene as a cause of the most cases of the thyroid hormone resistance syndrome. We have identified a novel nonsense mutation in codon 449 in the 3' end of exon 10 in the TR beta gene in a 16-year-old male patient with generalized resistance to thyroid hormone who also had familial thyroxine binding globulin deficiency. Receptor protein generated from this gene is thought to be 13 amino acid deficient at carboxy-terminus. Resistance to thyroid hormone was mild at least when the patient was evaluated. The patient was eumetabolic in the presence of elevated plasma-free thyroid hormone levels, and both thyrotrope and peripheral tissues responded to triiodothyronine (T3) administration. This mildness of resistance is in contrast to severe resistance to thyroid hormone in two previously reported cases with truncated receptors in which 16 amino acids or 11 amino acids were deficient at C-terminus. Thus, truncation of C-terminus of thyroid hormone receptor beta does not uniformly produce sever resistance.

Adolescent↗

A prospective randomized trial of the preventive effect of pre-operative transcatheter arterial embolization against recurrence of hepatocellular carcinoma.

To clarify whether pre-operative transcatheter arterial embolization (TAE) improves survival after hepatectomy, a prospective randomized comparative study was done. Of a total of 115 registered patients having solitary hepatocellular carcinoma (HCC) 2 to 5 cm in diameter, 18 (15.7%) were excluded after randomization. As a result, 97 patients were chosen as subjects and divided into two groups: hepatectomy with (group A: n=50) and without (group B: n=47) pre-operative TAE. The period of observation of the patients who survived the surgery was between 4.0 and 6.6 years. The randomization appeared to have provided well-balanced groups of patients and the clinico-pathological characteristics of the two groups were quite similar. The necrotic part of the cancerous lesions, as confirmed by operative specimens, amounted to 74.8+/-33.4% (mean +/-SD) in group A and 6.8+/-7.2% in group B (P<0.01). However, the cancer-free survival rates after hepatectomy in both groups showed little difference (39.1+/-7.0 (%+/-SE) and 31.1+/-0.1, respectively). We speculate that TAE is not effective against such HCC accessory lesions as minute intrahepatic metastasis and tumor thrombus and that pre-operative TAE does not improve post-operative survival.

Adult↗