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Biomedical subjects

T Nakatsu

Publications and source records attributed to T Nakatsu.

At least 37 records · Page 2Linked to original sources
PubMed1998

Pseudosarcomatous myofibroblastic tumor of the urinary bladder with massive intraperitoneal hemorrhage in a child.

A 3-year-old boy presented with persistent abdominal pain, hematuria and facial pallor with progressive anemia. A computed tomography scan showed a massive intraperitoneal hemorrhage and tumor mass in the bladder. Histological examinations of the resected tumor revealed findings of pseudosarcomatous myofibroblastic tumor (PMT). The clinico-pathological features of this case warn us that PMT can cause acute abdomen syndrome with massive intraperitoneal hemorrhage.

Abdomen, Acute↗
PubMed1998

Double-sector Lorenz plot scattering in an R-R interval analysis of patients with chronic atrial fibrillation: incidence and characteristics of vertices of the double-sector scattering.

Animal experiments have demonstrated that the minimum R-R interval during atrial fibrillation is proportional to the functional refractory period of the atrioventricular node. On Lorenz plots, atrial fibrillation is characterized by sector-shaped scattering; the vertex of the sector (ie, the minimum R-R interval) represents the functional refractory period. According to the atrioventricular nodal dual-pathway theory, it was hypothesized that the dual atrioventricular nodal pathways associated with chronic atrial fibrillation represent two vertices with two sectors. Detection of two-sector Lorenz plot scattering was attempted in 48 patients with chronic atrial fibrillation who underwent 24-hour ambulatory electrocardiography. Lorenz plot scattering was constructed by means of a computer. Two sectors, suggesting dual pathways, were detected in 19 (40%) of the 48 patients. The two vertices, located at 388 +/- 61 ms (mean +/- SD) and 580 +/- 60 ms were considered to represent the functional refractory periods of the fast and slow pathways, respectively. The vertex indicating the fast pathway showed greater circadian variation than that indicating the slow pathway. In one patient with dual-sector Lorenz plot scattering, whose atrial fibrillation spontaneously converted to sinus rhythm, an electrophysiologic study demonstrated dual atrioventricular nodal pathways. Thus, the Lorenz plot analysis identified two sectors, indicating the dual pathways, in approximately 40% of the patients with chronic atrial fibrillation, and the characteristics of the functional refractory periods of both pathways were estimated from the characteristics of the vertices. Although this study did not provide direct evidence of the dual atrioventricular nodal pathways, the analysis of Lorenz plot scattering may be clinically useful for studying the effects of drugs and/or ablation on the ventricular response in patients with atrial fibrillation based on the dual atrioventricular nodal pathway theory.

Aged↗
PubMed1997

Purification and characterization of tobacco pathogenesis-related protein PR-5d, an antifungal thaumatin-like protein.

Cultured tobacco cells accumulate several pathogenesis-related proteins. A neutral PR-5 protein, PR-5d, was purified to homogeneity from such cells. PR-5d has highly hydrophobic characteristics, but hydropathy analysis of its primary structure did not show a hydrophobic domain. In a series of bioassays, purified PR-5d showed inhibitory activity against several phytopathogenic and non-phytopathogenic fungi as do other members of the PR-5 protein family. To study the antifungal mechanism based on three dimensional structure of PR-5d, purified PR-5d was crystallized. The preliminary X-ray analysis of the crystal revealed that the crystals belong to space group C2, with cell dimensions a = 80.2 A, b = 63.8 A, c = 45.7 A, and beta = 107.2 degrees, and diffract at least 1.8 A resolution.

Amino Acid Sequence↗
PubMed1997

A large right coronary artery-left ventricle fistula with mild volume overload on the left ventricle owing to its capacitive action--pulsed Doppler and cineangiographic analyses in a patient.

A 54-year-old woman was admitted to our hospital because of a heart murmur without subjective symptoms. Angiography disclosed an enlarged right coronary artery and flow drainage into the left ventricle, ie, a large right coronary artery-left ventricle fistula. Analysis of pulsed Doppler studies and cineangiograms indicated considerable capacitance of this fistula owing to Windkessel action, which attenuated volume overload on the left ventricle. The features in this case suggest that evaluation of fistula hemodynamics is important in determining the overload on the ventricle through the fistula.

Blood Flow Velocity↗
PubMed1997

Decremental oscillation curve fitting of heart rate response following face immersion into cold water.

Using 18 healthy volunteers, we attempted to fit the heart rate response to a decremental oscillation curve by the least-squares method following facial immersion into cold water. The decremental oscillation equation was as follows: HR = alpha.e(-betat) sin omegat + gamma, where HR is the instantaneous heart rate at t s, alpha the maximum amplitude of the decremental oscillation, beta the decremental rate, omega the angular velocity and gamma the basal heart rate. Each subject immersed his/her face fully in a basin filled with ice-cold water (4 degrees C) for 30 s. The heart rate response to facial immersion was significantly fitted to the decremental oscillation curve with a correlation coefficient > 0.75 in all the trials. Double trials with a 15-min intertrial interval did not show any significant change in the coefficients. Atropine sulfate decreased the value of coefficient omega and increased that of gamma but did not change alpha or beta, indicating that omega is determined mainly by parasympathetic tone. There were no differences for any coefficient between men and women. The coefficients beta and gamma increased in association with age. Given the significant fitting to the decremental oscillation curve of the heart rate response, we propose that the corresponding electrical circuit consists of a resistance and an inductor connected in series, with a condenser in a parallel circuit with a direct current impulse. This method of fitting with the corresponding electric circuit may be useful for analysis of the heart rate response to physiological stimulus.

Age Factors↗
PubMed1997

Endoscopic lithotomy of common bile duct stones with sublingual nitroglycerin and guidewire.

OBJECTIVE: In 21 patients, our objective was the endoscopic removal of common bile duct stones by sphincter dilation with the application of sublingual nitroglycerin. METHODS: Nitroglycerin 0.3-0.6 mg was needed for proper dilation of the orifice and for successful cannulation of the Dormia basket into the bile duct. Cannulation of the Dormia basket was simplified by placing the guidewire in the common bile duct beforehand. Because of possible stone impaction, a mechanical lithotriptor was applied smoothly in two patients. RESULTS: Complete stone removal was successful in 18 of the 21 (86%) patients. One patient who developed a mild form of acute pancreatitis recovered in a few days by conservative management with drip infusion of protease inhibitor. Blood pressure dropped transiently in a patient receiving nitroglycerin, but the general condition of the patient was stable. CONCLUSIONS: This procedure was found to be safe, easy, and effective in extracting common bile duct stones.

Acute Disease↗
PubMed1996

Crystallization and preliminary crystallographic study of asparagine synthetase from Escherichia coli.

Crystals of Escherichia coli asparagine synthetase have been obtained from 45% saturated ammonium sulfate solution at pH 7.5 by using its Cys-free (Cys51-->Ala, Cys315-->Ala) mutant. The crystals belong to space group P2(1), with cell dimensions a = 52.90(4), b = 126.2 (2), c = 52.8 (1) A and beta = 105.3(1) degrees. The self-rotation function specifies that there is one dimer in the asymmetric unit and the subunits are related by a non-crystallographic twofold axis. Complete data sets up to 2.7 A resolution have been collected on an R-AXIS IIc imaging-plate system.

Journal Article↗
PubMed1996

Increased expression of cytokines in liver and serum in patients with extrahepatic diseases.

To determine whether the liver plays an immunological role in certain extrahepatic disorders, we investigated the expression of interleukin (IL)-1 beta, IL-6, interferon (IFN)-gamma, and tumor necrosis factor (TNF)-alpha in 11 patients who had recovered from cholecystolithiasis, 12 patients with gastric cancer, 20 patients with chronic hepatitis, and 6 healthy controls. Cytokine mRNAs in the liver were detected by semiquantitative reverse transcribed-polymerase chain reaction. Serum cytokines and soluble IL-2 receptor (sIL-2R) were investigated by enzyme-linked immunosorbent assays. Increases in TNF-alpha, IL-6, IL-1 beta, and IFN-gamma mRNAs were found in the livers of patients with extrahepatic diseases. TNF-alpha and IL-6 peptides were increased in the sera of patients with gastric cancer. TNF-alpha in the sera and TNF-alpha mRNA in the liver were correlated in gastric cancer patients. Surprisingly, sIL-2R in the serum of gastric cancer patients was significantly higher than the level in healthy controls. Our findings suggest that the liver produces cytokines in reaction to extrahepatic lesions. Further, the increase in sIL-2R in gastric cancer patients indicates that malignancy may affect the immune network in vivo.

Biopsy, Needle↗
PubMed1996

Scanning of polypoid gallbladder lesions by ultrasonic microprobes using transpapillary catheterization.

BACKGROUND AND STUDY AIMS: Polypoid lesions of the gallbladder can be diagnosed by transabdominal ultrasonography and endoscopic ultrasonography. However, the image resolution is limited, and the histopathology of these lesions is difficult to determine. We report here on our preliminary results in four patients using a high-frequency (20 MHz) ultrasonic microprobe introduced into the gallbladder via the transpapillary approach. PATIENTS AND METHODS: Insertion of the microprobe into the gallbladder through the papilla of Vater was attempted in four patients with gallbladder diseases without preceding endoscopic sphincterotomy. RESULTS: The lesions in the gallbladder were clearly visualized in three of the four patients. We tried to correlate the characteristic ultrasound findings with the histopathology of the lesions, which were found to be early cancer, adenoma, and adenomyomatosis on histopathology of the specimens after cholecystectomy. No complications occurred. CONCLUSIONS: High-resolution endoscopic transpapillary ultrasonography of the gallbladder is feasible and safe, and may contribute to the diagnosis of gallbladder diseases, particularly of small polypoid lesions.

Adenoma↗
PubMed1995

Papillary dilation vs sphincterotomy in endoscopic removal of bile duct stones. A randomized trial with manometric function.

To circumvent the long-term effects of papillary ablation for extracting common bile duct stones (< 12 mm in diameter) in endoscopic sphincterotomy (EST), endoscopic papillary dilation (EPD) was attempted in 20 patients. To evaluate papillary function before and after the procedures, manometry of the sphincter of Oddi was carried out in 13 with EPD and 10 of 20 patients with EST. Extraction of all stones was successful (100%) in both groups at an equal rate. Repeated numbers of procedures were common in both groups. However, the mean duration of the procedure was high in EPD compared to EST (63 min vs 42 min, P < NS). Adjunctive therapies like mechanical lithotripsy (ML), nasobiliary drainage, and choledochoscopy were included in EPD, while EST required a basket catheter and ML. There was no significant difference on manometry before and after the procedures (P = NS), although papillary function was found to have decreased after the EPD. In contrast, all patients in the EST group lost papillary function after the procedure. Thirty-day morbidity and mortality rate were absent in both groups. Immediate and 2.5-year follow up complications were uncommon in both groups. As a simple method, EPD may be an effective and safe alternative to EST in the management of patients with bile duct stones who require maintenance of papillary function.

Aged↗
PubMed1995

[A study on the effect of cepharanthin, a biscoclaurine alkaloid, on enhancement of mitogen-induced histidine decarboxylase activity in mice spleens and the effect of histamine on the production of cytokines].

The effect of cepharanthin on the enhancement of mitogen-induced histidine decarboxylase (HDC) activity in mice spleens and the effect of histamine on the production of cytokines were investigated. Cepharanthin enhanced LPS-induced HDC activity in normal mice spleens and also enhanced it in genetically T cell-deficient nude mice spleens and T and B cell-deficient scid mice spleens. Therefore, cepharanthin can exert its effect on macrophages without T cells or B cells. Cepharanthin enhanced LPS-induced cytokine production by macrophages. Histamine induced cytokine production and enhanced LPS-induced cytokines production by macrophages. However, diphenhydramine and cimetidine, histamine receptor antagonists, did not block this process. Alpha-fluoromethylhistidine, a suicide inhibitor of HDC, suppressed LPS-induced cytokine production. These results suggest that cytokine production by macrophages is regulated by both histamine added exogenously and histamine induced by macrophages themselves and that histamine participates in enhancement of cytokine production by cepharanthin.

Alkaloids↗
PubMed1995

[Endoscopic lithotomy using sublingual nitroglycerin].

After medical sphincter dilation using sud-lingual nitroglycerin, endoscopic removal of common bile duct stones in 15 patients was carried out. Complete stone removal was obtained in 14 of 15 patients. Only 0.3 mg to 0.6 mg nitroglycerin was needed to give an enough dilation of the orifice for cannulating the basket catheter into the bile duct. Mechanical lithotriptor was smoothly cannulated in one patient because of possible impaction. Blood pressure was dropped transiently in one patient by nitroglycerin, however, the general condition of the patient was stable. This procedure is safe, easy and effective in preserving sphincter function. Acute cholecystitis, a common complication of persistent gallbladder stone after endoscopic sphincterotomy, may be avoided by employing this method. More clinical studies, on long term and in a large scale of patients, are necessary to reduce complications that usually occur after sphincterotomy.

Female↗
PubMed1994

Direct dissolution of gallstones with methyl tert-butyl ether (MTBE) via endoscopic transpapillary catheterization in the gallbladder (ETCG).

In a pilot study of direct dissolution therapy of gallstones with methyl tert-butyl ether (MTBE), endoscopic transpapillary catheterization in the gallbladder (ETCG) was performed. Complete dissolution was seen in 8 out of 12 (66%) patients and partial dissolution was seen in 2 (16%) patients. In one of the 8 complete dissolution patients, combined extracorporeal shock wave lithotripsy (ESWL) and dissolution therapy was carried out successfully. These 8 patients were followed up for 12-20 months with regular ultrasonography. During this period, 1 patient underwent laparoscopic cholecystectomy due to stone recurrence. Thickening of the gallbladder wall was seen in 2 patients, but there were no other complications. Using Tsuchiya's classification based on ultrasound, complete dissolution was seen in type Ia stones. This pilot study suggests that the direct dissolution of gallstones with MTBE via ETCG might be a useful and safe non-invasive treatment in patients with cholesterol stones in preserved gallbladders.

Adult↗
PubMed1994

Silent zone on Lorenz plots of the ventricular response before termination of paroxysmal atrial fibrillation--report of a case.

An ambulatory 24 h Holter electrocardiogram was recorded during paroxysmal atrial fibrillation in a 67-year-old man. His paroxysmal atrial fibrillation terminated spontaneously approximately 12 h after the start of recording. The RR variability of this Holter recording was studied using Lorenz plots, frequency domain analysis, and time domain analysis. A silent zone appeared on the Lorenz plots beginning a few hours before the termination of his attack. The coefficient of variance (CV) and the power of the high-frequency component of RR variability (HF) gradually increased toward the termination. The silent zone was closely related to the functional refractory period of the atrioventricular node estimated from the Lorenz plots, and the functional refractory period was significantly correlated with the CV and HF power of RR variability. This case suggests that a silent zone on Lorenz plots reflects increased parasympathetic tone. In addition, such a silent zone may be useful for predicting the course of paroxysmal atrial fibrillation and for evaluating the role of the autonomic nervous system in this condition.

Aged↗
PubMed1990

Autoregulation by the right coronary artery in dogs with open chests; comparison with the left coronary artery.

Experiments were conducted to study autoregulatory responses of the right and left coronary arteries in dogs with open chests. The right and left circumflex coronary artery were cannulated and perfused with blood from the femoral artery via a pressurized reservoir. The perfusion pressure was varied in steps over a wide range and coronary blood flow rates were measured. Both the right and left coronary arteries exhibited autoregulation but the pressure at the end of the autoregulatory range was lower in the right (39.8 +/- 9.1 mm Hg) than in the left circumflex coronary artery (57.6 +/- 14.5 mm Hg). The slope of the pressure-flow relationship in the autoregulatory range was less steep in the right than the left circumflex coronary artery. The closed-loop gain when the perfusion pressure was less than 100 mm Hg was greater in the right than in the left circumflex coronary artery. Increases in the right ventricular afterload produced by pulmonary artery constriction decreased the closed-loop gain, shifted the auto-regulatory range upward and to the right, and made the slope steeper. These results indicate that more effective autoregulation is carried out by the right than the left circumflex coronary artery.

Animals↗