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Biomedical subjects

H Nakatani

Publications and source records attributed to H Nakatani.

At least 37 records · Page 2Linked to original sources
PubMed2000

Sarcoidosis with vocal fold involvement and hypercalcaemia.

Sarcoidosis affects many different organ systems. However, laryngeal involvement is rare and most cases with laryngeal involvement affect the supraglottis, occasionally secondarily extending to the vocal fold. The features of sarcoidosis in the supraglottic region have been described in several reports, but vocal fold involvement has not been presented in detail. We report an unusual case of laryngeal sarcoidosis initially involving the vocal folds in a 66-year-old man, associated with hypercalcaemia. Our report describes characteristics of the involved vocal folds. Hypercalcaemia is one of the characteristics of sarcoidosis. We concluded that laryngeal sarcoidosis should be added to the differential diagnosis of vocal fold lesions, particularly in patients with hypercalcaemia.

Aged↗
PubMed2000

[A successful case of hybrid therapy for the left main trunk and triple coronary vessel lesions with acute myocardial infarction and cardiogenic shock].

A 86-year-patient who had acute myocardial infarction and critical cardiogenic shock was diagnosed to have the left main trunk (LMT) and triple vessel disease. Emergent coronary artery bypass grafting to the left anterior descending artery was performed using saphenous vein graft without cardiopulmonary bypass through median sternotomy. On the 41st postoperative day, catheter intervention was performed to the remaining lesions by stenting of LMT and percutaneous transluminal coronary angioplasty to the right coronary artery lesions. Tl scintigraphy showed remarkable reduction of myocardial ischemia. Hybrid therapy is the effective new strategy for critical cases which cannot be successfully and securely treated by medical or surgical approach alone.

Aged↗
PubMed1999

Monte Carlo simulation of 4-alpha-glucanotransferase reaction.

4-alpha-Glucanotransferase (GTase, D-enzyme) catalyzes disproportionation between two short polymers of maltooligosaccharides linked by alpha-1,4-glucoside bonds. Using action modes of the potato GTase for the donor and acceptor substrates, the Monte Carlo method was applied to simulate the GTase reaction. The simulation starts from a single enzyme molecule and a finite number (10(5)) of substrate molecules. All selection processes were performed using random numbers produced by computer. The initial substrates were from trimer to 10-mer. In every case, the final stage was the steady-state distribution of polymers. The steady-state distribution by the potato GTase reaction was different from those by the hypothetical random disproportionation reaction. The simulated data from the reaction of potato GTase and trimer almost quantitatively agreed with experimental data. The mechanism of the GTase reaction was accumulation of probabilistic processes and was well simulated by the Monte Carlo method. GTase randomizes the overall distribution of chain length of the substrate. Therefore the GTase reaction is an entropy-driven process.

Algorithms↗
PubMed1999

[Decreased plasma soluble P-selectin level in coronary sinus after successful coronary angioplasty in patients with unstable angina].

P-selectin, an adhesion molecule, is involved in the alpha-granules of platelets with several factors such as platelet factor 4 (PF-4) and in Weibel-Parade bodies of endothelial cells with von Willebrand factor. The levels of the soluble form of P-selectin increase after angina episodes in patients with unstable angina, indicating that soluble P-selectin is associated with platelet activation and thrombogenesis in the coronary circulation. To evaluate the effect of successful coronary angioplasty on platelet activation or thrombogenesis in the coronary circulation, plasma soluble P-selectin, PF-4 and von Willebrand factor antigen levels were measured in blood obtained from the coronary sinus before and after successful coronary angioplasty in 15 patients with unstable angina. Fifteen patients with normal coronary angiograms served as controls. Plasma P-selectin, PF-4 and von Willebrand factor antigen levels were determined by sandwich enzyme-linked immunosorbent assays. Increased plasma soluble P-selectin (159.7 +/- 74.5 vs 78.7 +/- 26.4 ng/ml, p < 0.01) and PF-4 (456.5 +/- 87.0 vs 118.7 +/- 62.3 IU/ml, p < 0.01) levels were found in patients with unstable angina compared with those in controls, and were significantly decreased after angioplasty (147.8 +/- 69.6 ng/ml, p < 0.05; 401.6 +/- 108.5 IU/ml, p < 0.05), whereas von Willebrand factor antigen was unchanged. The ratio of plasma soluble P-selectin levels after and before angioplasty correlated with the corresponding ratio of plasma PF-4 levels (r = 0.53, p < 0.05), but not with the ratio of plasma von Willebrand factor antigen levels. The plasma levels of soluble P-selectin, which increase in the coronary circulation in patients with unstable angina, decrease after successful coronary angioplasty. Such data indicate that soluble P-selectin is associated with platelet activation and the therapeutical procedure improves the thrombogenic state in the coronary circulation.

Aged↗
PubMed1999

Reliable method of monitoring antidromic facial nerve response stimulated via Stensen's duct.

OBJECTIVE: This study aimed to obtain a clear antidromic facial nerve response (ADFNR) with a high detection rate in human subjects. The authors also describe the clinical utility of this technique. BACKGROUND: The ADFNR is a potential that can be used to monitor intratemporal facial nerve function at the early stage of facial palsy. However, it was difficult to obtain an analyzable response with conventional methods. METHODS: The sensitivity of data recorded by percutaneous stimulation conventionally used was compared with those recorded after stimulation through Stensen's duct, and the type of recording electrode was evaluated. In individual normal subjects, the test-retest and right-left differences were compared. RESULTS: The ADFNR elicited by stimulation through Stensen's duct and recorded with a monopolar needle electrode was a useful method to monitor facial nerve impulses. With the use of these methods, the ADFNR detection rate was more than 90%. The test-retest difference was minimal and smaller than the right-left side difference. CONCLUSIONS: The authors recommend that the ADFNR should be used to evaluate changes of unilateral facial nerve function by repeated testing and that the technique described here is useful for monitoring the early changes of facial nerve function in patients with facial palsy.

Adult↗
PubMed1999

Improved recording techniques of antidromic facial nerve response for outpatient clinical use.

OBJECTIVE: The purpose of this study was to obtain an analyzable wave of the antidromic facial nerve response (ADFNR) without interference of the compound muscle action potential (CMAP) at the outpatient clinic setting. BACKGROUND: To evaluate intratemporal facial nerve function with the ADFNR, it is necessary to analyze the waveform of propagating nerve impulses in the temporal bone. However, this small nerve response is easily disturbed by the CMAP, which is simultaneously evoked by electrical stimulation. METHODS: The ADFNR was recorded at the entrance of the external ear canal and simultaneously at the anulus tympanicus. Subtraction between the responses evoked at both sites was performed to eliminate the CMAP. RESULTS: The ADFNR was recorded after subtraction of the response recorded at the entrance of the external ear canal from that at the anulus tympanicus. The normal ADFNR had a triphasic waveform. With the placement of the reference electrode at the entrance of the external ear canal, the responses were similar to the subtracted responses. CONCLUSIONS: We recommend the subtraction method and placement of the reference electrode at the entrance of the external auditory canal to record an analyzable ADFNR and to simplify the recording techniques.

Action Potentials↗
PubMed1998

[Efficacy and safety of a single oral dose of pilsicainide in supraventricular arrhythmia after coronary artery bypass grafting].

We evaluated the efficacy and safety of administration of a single oral dose of Pilsicainide, a class Ic antiarrhythmic agent, in 34 patients (26 men, 8 women, age from 48 to 81, mean age 66 +/- 8 years) who developed supraventricular arrhythmia after coronary artery bypass grafting (CABG). A total of 42 episodes of postoperative supraventricular arrhythmia, with the majority occurring 2-4 days after CABG, were classified as follows: paroxysmal atrial fibrillation, 34; paroxysmal atrial flutter, 6; and sinus tachycardia, 2. Sinus rhythm was restored in 32 episodes (78%) by treatment with oral pilsicainide given in a single dose of 50 ro 100 mg. Successful conversion was obtained within 90 minutes in 44% and 3 hours in 56% of episodes, with a mean conversion time of 119.2 +/- 107.5 minutes after the administration of pilsicainide. The mean conversion times tended t highlight the difference between the 50 mg and 100 mg doses, but this difference was not statistically significant (p = 0.053). The ventricular rate was significantly reduced from 123.3 +/- 29.5 beats/min to 85.6 +/- 19.9 beats/min (p < 0.0001), however no significant changes in blood pressure or no significant side effects were observed. The results of the present study suggest that a single oral dose of pilsicainide, administered for its favorable pharmacokinetic profile and lack of hemodynamic side effects, is a valuable drug for converting supraventricular arrhythmia to sinus rhythm in most patients after CABG.

Aged↗
PubMed1998

[Hemodynamic evaluations of patients with small aortic annulus with St. Jude Medical prosthetic heart valve].

As the elderly population in Japan increases, senile degenerative aortic valvular disease also tends to increase. These patients often have a small aortic annulus. The problem of "valve-patient-mismatch" occurs when a small prosthesis is inserted into a patient with a small aortic annulus. To avoid annular enlargement after aortic valve replacement (AVR), we tried to use a small-sized St. Jude Medical (SJM) valve. From September 1988 through November 1996, 110 AVR were performed in our institution. In these cases, 30 underwent AVR with a small sized SJM valve (male < or = 21 mm, female < or = 19 mm). Dobutamine stress echocardiography was performed in 19 patients who had undergone AVR with a small-sized SJM valve. Surgical results were also compared between patients with small aortic annulus and those with normal-sized aortic annulus. Using Doppler echocardiography, pressure gradients (PG), cardiac index (CI), effective orifice area (EOA), and performance index (PI) were calculated at rest and during stress. The mean body surface area (BSA) of patient who had undergone AVR with SJM19A, 19HP and 21A was 1.40, 1.42 and 1.56 m2, respectively. With dobutamine stress, heart rates, PG and CI increased significantly. Mean and maximum PG of patients with 19HP (8.0 and 15.4 mmHg at rest, 12.9 and 28.0 mmHg under stress, respectively) and 21A (9.5 and 19.1 mmHg at rest, 16.5 and 35.3 mmHg under stress, respectively) were relatively low. EOA index (EOAI) of patient with 19HP showed the highest values mean 0.93 cm2/m2. PIs tended to be higher with HP models than with standard models. The tests were completed without significant side effects such as frequent ventricular arrhythmias. Among the cases with small aortic annulus, there were no operative deaths or hospital deaths. There were also no late deaths, episodes of hemorrhage or thrombosis. Conclusions. In our institution, AVR was performed safely without any aortic annular enlargement with a small aortic anulus in small BSA patients. Postoperative hemodynamic data obtained by echocardiography were satisfactory for all patients at rest and even during maximum dobutamine stress test.

Aged↗
PubMed1998

Inhibitory effects of rebamipide on ENNG-induced duodenal carcinogenesis in mice: a possible strategy for chemoprevention of gastrointestinal cancers.

Rebamipide is a potent antioxidative agent; it increases gastric mucosal PGE2 production and thus protects the gastric mucosa. We hypothesized that the mechanisms of ulcer formation could be extended to carcinogenesis and that an increase in gastric mucosal protection may result in a decrease in gastric carcinogenesis. Therefore, we assessed the inhibitory effects of rebamipide on N-ethyl-N'-nitro-N-nitrosoguanidine (ENNG) -induced carcinogenesis in mice. The percentage of tumor-bearing mice in three treatment groups--ENNG + rebamipide 20 mg, ENNG + rebamipide 50 mg, and ENNG alone--was 55%, 42%, and 67%, respectively. The incidence of tumorigenesis tended to decrease with increasing doses of rebamipide. The difference between ENNG + rebamipide 50 mg and ENNG alone was statistically significant (P < 0.05). These results suggest that rebamipide may strengthen the host defense mechanisms related to carcinogenesis in the digestive tract.

Alanine↗
PubMed1997

Monte Carlo simulation of multiple attack mechanism of beta-amylase-catalyzed reaction.

beta-Amylase (EC 3.2.1.2) produces maltose (dimer) from the nonreducing ends of alpha-1,4 glucosidic bonds of substrates like maltooligosaccharides, amylose, and amylopectin. The enzyme releases several maltose molecules from a single enzyme-substrate complex without dissociation by multiple or repetitive attack containing many branching reaction paths. The Monte Carlo method was applied to the simulation of the beta-amylase-catalyzed reaction including the multiple attack mechanism. The simulation starts from a single enzyme molecule and a finite number of substrate molecules. The selection of the substrate by the enzyme and degree of multiple attack proceeds by random numbers produced from a computer. The simulation was carried out until the whole substrate and the intermediate molecules were consumed. The simulated data were compared with experimental data of sweet potato beta-amylase using heptamer, octamer, nanomer, and 11-mer as substrates. The only adjustable parameter for odd-numbered substrates was the probability of multiple attack, while an additional adjustable parameter (a correction factor due to low reactivity of tetramer) was needed for even-numbered substrates.

Catalysis↗
PubMed1997

[A case report of aorto-coronary artery bypass surgery in patient with essential thrombocythemia].

Essential thrombocytosis was detected by chance in a 55-year-old patient with angina pectoris when cardiac catheterization was performed. The diagnosis of thrombocytosis (platelet count > 1,000000/mm3) was established by detailed investigations. This patient had stenosis of the coronary arteries and the right common iliac artery. About one month after cardiac catheterization, the patient underwent coronary bypass surgery following normalization of the platelet count with interferon therapy, which was also used to control the platelet count perioperatively. The operation was completed without major problems, and the postoperative course was uneventful. This case is reported in detail.

Angina Pectoris↗
PubMed1997

[A case report of multiple aneurysms of pancreaticoduodenal region with celiac obstruction].

We treated a 53-year-old man who had a dorsal pancreatic aneurysm and three pancreaticoduodenal aneurysms with celiac obstruction. Resection of the dorsal pancreatic aneurysm and bypass grafting from abdominal aorta to common hepatic artery with his saphenous vein were performed. A diagnosis of the aneurysm caused by arteriosclerotic changes was confirmed by the pathohistological findings. The postoperative clinical course was uneventful and angiography revealed disappearance of the left pancreaticoduodenal aneurysms. These findings suggest that not arterioscrelotic changes but also circulatory disturbance caused by celiac obstruction are reasonable as a part of etiology in growth of aneurysms.

Aneurysm↗
PubMed1996

Inhibition of mucosal lipid hyperoxidation by green tea extract in 1,2-dimethylhydrazine-induced rat colonic carcinogenesis.

Phosphatidylcholine hydroperoxide (PCOOH) measured using a chemiluminescence detector to examine colonic mucosal lipid hyperoxidation increased after injection of 1,2-dimethylhydrazine and green tea extract (GTE), which we previously showed inhibited carcinogenesis and oxidative DNA damage in the gastrointestinal tract. Therefore, the hyperoxidation of membrane phospholipids reflected well the degree of DNA damage and carcinogenic alteration, and may be a useful intermediate biomarker for initiation of carcinogenesis.

1,2-Dimethylhydrazine↗
PubMed1996

Overexpression of bax sensitizes human breast cancer MCF-7 cells to radiation-induced apoptosis.

Resistance to apoptosis plays an important role in tumors that are refractory to chemotherapy and ionizing radiation (IR). bax, which forms a heterodimer with bcl-2 and accelerates apoptosis, is not, or only weakly, expressed in most human breast cancer cells, and weak bax expression is considered to be related to the resistance of breast cancer cells to apoptosis. bax expression vector was introduced to human breast cancer MCF-7 cells, which exhibit weak expression of bax, to demonstrate its role of modulating radiation-induced apoptosis. bax overexpression in MCF-7 cells by stable transfection does not affect viability by itself, but each stable transfectant was more sensitive to IR than the parental MCF-7 cells. The degree of enhancement in radiosensitivity was dependent on the expression level of bax. IR upregulated p53 and p21WAF1 about 5- to 10-fold and downregulated bcl-2 and bcl-XL by 80-90% at 6 hr in both parent and bax stably transfected MCF-7 cells to the same degree. FACS analysis and DNA electrophoresis revealed that this sensitization was due to apoptosis. We suggest that exogenous bax expression might be one of the factors determining cellular radiosensitivity in MCF-7 breast cancer cells and may have therapeutic applications for enhancing radiation sensitivity in breast cancer cells.

Apoptosis↗
PubMed1996

Inhibitory effects and toxicity of green tea polyphenols for gastrointestinal carcinogenesis.

BACKGROUND: Recently, and epidemiologic study showed a lower risk of gastrointestinal carcinogenesis in green tea drinkers. An experiment on two-stage skin carcinogenesis in mice showed that (-)-epigallocatechin gallate (EGCG), one of the main constituents of green tea, inhibited tumor formation. METHODS: The inhibitory effects of EGCG and green tea extract (GTE) on N-ethyl-N'-nitro-N-nitroguanidine (ENNG)-induced duodenal carcinogenesis in the mouse, N-methyl-N'-nitro-N-nitrosoguanidine (MNNG)-induced carcinogenesis of the glandular stomach in the rat, and azoxymethane-induced colon carcinogenesis in the rat were examined. The toxicity of GTE was assessed experimentally and GTE was applied clinically in normal volunteers to determine the effective dose and to assess its harmful effects. RESULTS: EGCG and GRE inhibited chemical carcinogenesis of the gastrointestinal tract in rodents. Judging from the epidemiologic and experimental findings, it was determined that 1 g per day of GTE might be an effective dose. GTE was not toxic and no harmful effect was found during its clinical use. CONCLUSIONS: These findings suggest that EGCG and GTE are useful in preventing gastrointestinal carcinogenesis, and the clinical usefulness of GTE, which has no harmful effects and is inexpensive, should be studied further.

Animals↗
PubMed1996

Monte Carlo simulation of multiple attack mechanism of alpha-amylase.

Porcine pancreatic alpha-amylase (EC 3.2.1.1) produces short maltooligosaccharides from a single enzyme-substrate complex without dissociation by multiple or repetitive attack. Multiple attack is caused by relative sliding of the enzyme along the product chain of the enzyme-product complex without dissociation to form another productive complex. The Monte Carlo method was applied to the multiple attack mechanism to predict product distribution from amylose and amylopectin molecules of arbitrary sizes. The position of the initial attack to make the enzyme-substrate complex and branched reaction paths from the enzyme-product complex were selected by random numbers and probabilities. A simulated product distribution from 100,000 samples of amylose of chain length greater than 80 agreed completely with experimental data at the early stage of hydrolysis of amylose of mean chain length 90. On the other hand, the simulated product distribution from amylopectin agreed with experimental data of potato amylopectin when the effective chain length of the A chain was 9. Since the mean chain length of the A chain of potato amylopectin is 15, it is possible that amylopectin is partially compact in solution, so that the enzyme can recognize and act only on the outer side of the A chain at the early stage of digestion.

Amylopectin↗
PubMed1996

[The evaluation of the bio-compatibility and the clinical usefulness of heparin-coated cardiopulmonary bypass circuits].

We studied the biocompatibility and the clinical usefulness of heparin-coated cardiopulmonary bypass circuits (Duraflow-II) compared with non-coated circuits. First study was done to clarify the biocompatibility of heparin coated circuit. 33 cases of elective coronary artery bypass grafting were randomized into two grops. Both group had full dose heparin in this study and laboratory tests were done such as blood cell count, free hemoglobin, AT-III, fibrinogen, FDP, and complement system. The use of heparin-coated circuits resulted in a reduction of C3a generation, and a reduction of fibrinogen consumption. The decline of AT-III may be due to bonding of coated heparin to AT-III, leading to effective anticoagulation. Next study was carried out in 26 cases. In heparin coated group, the amount of heparin was reduced to 200 IU/kg compared to 350 IU/kg in control group. ACT was maintained above 300 sec. and 400 sec. respectively. The amount of post operative bleeding was identical in both groups. There was no case which required autologous blood transfusion, re-operation for bleeding in both groups. Myocardial infarction and hospital mortality were not seen in this study. Concerning the fear of graft occlusion in low dose heparin surgery, there was no statistical difference of graft patency in both groups. In conclusion, heparin coated CPB circuits (Duraflo-II) are favorable in the meaning of biocompatibility and sefely used with low dose heparin.

Biocompatible Materials↗