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Biomedical subjects

T Kawada

Publications and source records attributed to T Kawada.

At least 253 records · Page 14Linked to original sources
PubMed1990

[A successfully treated case of infective endocarditis due to Candida tropicalis].

A 34-year-old man, a heavy drinker, was admitted with a high fever and hematuria two months previously. Surgery was performed for acute sever pancreatitis and postoperatively antibiotics were administered with intravenous hyperalimentation. After discharge he was readmitted and infective endocarditis was strongly suspected because of high fever, hematuria, Osler's nodes, Janeway's lesions, splinter hemorrhages and mitral regurgitation. Penicillin G in combination with Gentamycine therapy was started on the first hospital day. On the second hospital day, blood culture revealed Candida tropicalis so Miconazole therapy was commenced. On the forth hospital day, he underwent surgery for replacement of a mitral prosthesis with a prosthetic valve because he had embolus in the radial artery. Despite intensive antifungal therapy, he showed no improvement in clinical symptoms. Then we changed the antifungal drug from Miconazole to Amphotericin B and 5-fluorocytosine. On the 109th hospital day, his clinical symptoms improved. Antifungal therapy was halted and at present 10 months later, he is healthy.

Adult↗
PubMed1990

Studies on the synthesis of compounds related to adenosine-3',5'-cyclic phosphate. VI. Synthesis and cardiac effects of N6,N6,2'-O-trialkyl-, N6,2'-O-dialkyl-, and 2'-O-alkyladenosine-3',5'-cyclic phosphates.

The alkylation of adenosine-3',5'-cyclic phosphate (cAMP, 1) with alkyl bromides was investigated and various new alkylated cAMP derivatives, N6,N6,2'-O-trialkyl cAMPs (2), N6,2'-O-dialkyl cAMPs (3) and 2'-O-alkyl cAMPs (4), were prepared by a one step reaction without the introduction of a protecting group into 1. Compounds (2) were synthesized from 1 by treatment with alkyl bromides in the presence of NaH or potassium tert-butoxide in dimethyl sulfoxide. Compounds (3) were also synthesized from 1 under conditions similar to those of the synthesis of 2 except for the use of MeONa as a base. Compounds (4) were prepared from 1 by treatment with alkyl bromides in the presence of 18-crown-6 in dioxane-aqueous KOH solution. N6,2'-O-Dibenzyl cAMP (3e) was obtained from 1 by the same method as the preparation of 4. These new alkylated derivatives were evaluated for cardiotonic activity in vitro. Some of them showed weak positive inotropic effects and strong negative chronotropic effects. Thus, the presence of the 2'-hydroxyl group seemed to be essential for the appearance of potent positive inotropic activity caused by cAMP derivatives.

Animals↗
PubMed1990

Studies on the synthesis of compounds related to adenosine 3',5'-cyclic phosphate. VII. Synthesis and cardiac effects of N6,N6-dialkyl adenosine 3',5'-cyclic phosphates.

A series of novel N6,N6-dialkyl adenosine 3',5'-cyclic phosphates N6,N6-dialkyl cAMPs) was synthesized from 2'-O-p-toluenesulfonyl cAMP (2'-O-tosyl cAMP, 2) and tested for inotropic and chronotropic activities in vitro. Treatment of 2 with excess alkyl halides and sodium hydride followed by detosylation with aqueous NaOH readily gave N6,N6-dialkyl cAMPs (3) in good yields. Various N6,N6-dialkyl cAMPs having different alkyl groups at the N6-position (9-12) were prepared by alkylation followed by detosylation of N6-alkyl-2'-O-tosyl cAMPs (4) which were obtained by the reductive alkylation of 2 with aldehydes in the presence of sodium cyanoborohydride in acetic acid or tosylation of N6-methyl cAMP. The mechanism of the detosylation is briefly discussed. Among the N6,N6-dialkylated derivatives, N6,N6-dipentyl (3f) and N6-ethyl-N6-heptyl (10e) derivatives were found to exhibit a potent positive inotropic effect and a weak positive chronotropic effect. The structure-activity relationships for the position and the length of alkyl residue are discussed.

Alkylation↗
PubMed1990

[EMG analysis of masticatory muscle fatigue and recovery rate during gum chewing].

An EMG computer analysis system was developed to analyze the mandibular function. The system enabled measurements of the masticatory muscle's rhythm, activity, and power spectrum for the same EMG burst during mastication. This study revealed that a power spectrum analysis was able to be carried out by a fast Fourier transform algorithm of the isometric contraction components of EMG bursts during mastication. The normal regulatory mechanism of the mandibular function was temporarily disturbed by clenching to inflict fatigue upon the masticatory muscles. EMG analysis of the masticatory muscles during gum chewing were observed before and immediately after clenching, and during their recovery periods. After fatigue induction, all of the masticatory rhythms of the masticatory muscles showed a decrease in EMG burst duration time (duration) and duration per cycle (D/C) that recovered with time. However, only the coefficient variation of the duration and D/C in the working side increased immediately after fatigue induction. The power spectrum shifted to a lower frequency immediately after fatigue induction, and recovered along with time. Furthermore, it was found that EMG activity influenced the power spectrum during gum chewing. In conclusion, this EMG analysis system may be used as a possible future diagnostic aid for mandibular dysfunction syndromes.

Chewing Gum↗
PubMed1990

[Treatment of ureteral calculi by extracorporeal shock wave lithotripsy].

We reviewed 465 cases of ureteral calculi treated at Jömö Urological Hospital using a Dornier HM3 lithotripter during the period from October 1985 to February 1989. The 336 men and 122 women ranged from 11 to 78 years old with a mean age of 42.2. The stone size ranged from 4 mm to 30 mm with a mean length of 10.6 mm. Complete stone elimination by ESWL was achieved in 431 of the 465 cases (92.7%). The success rate was best for stones in the lower ureter, which was 98.1 per cent (53/54). For upper and mid ureteral calculi it was 92.4 per cent (363/393) and 83.3 per cent (15/18), respectively. ESWL after push up made 100 per cent (30/30) of patients completely free of stones, while ESWL after bypass 93.0 percent (106/114) and ESWL in situ 91.9 per cent (295/321). The rate of residual stone increases in proportion to the age of patients. Minor side effects such as fever and pain were observed. Our results suggest that ESWL currently is the first therapeutic option for the majority of ureteral calculi.

Adolescent↗
PubMed1990

[Regulation of coagulo-fibrinolytic activity and lupus anticoagulants in systemic lupus erythematosus].

We determined the following coagulo-fibrinolytic activities in 24 patients with systemic lupus erythematosus (SLE) and 20 healthy adults: prothrombin time (PT), activated partial thromboplastin time (A-PTT), factor VIII: coagulant activity), von Willebrand factor antigen (vWF: Ag), antithrombin-III (AT-III), plasminogen (PLG), alpha 2 plasmin inhibitor (alpha 2 PI), alpha 2-plasmin inhibitor-plasmin complex (PIC), protein C (PC: activity and antigen concentration), and protein S (PS: total PS and free PS). PLG, AT-III, PC antigen concentration and total PS were significantly decreased in ten female controls as compared with ten male controls. Therefore, we used the ten healthy females as controls and excluded two male SLE patients in the analysis of the correlations of coagulo-fibrinolytic activities with lupus anticoagulant (LA), clinical and laboratory features in 22 female patients with SLE. In the SLE patients, PT was significantly shortened, while A-PTT was prolonged. PLG, PC activity and antigen, and total PS were significantly increased, and free PS levels were decreased in SLE. The shortened PT and decreased free PS suggest hypercoagulable states in SLE patients. A significant prolongation of A-PTT and a decrease of F VIII activity were observed in the six LA-positive SLE patients, and the results were considered as known effects of LA. Furthermore, vWF: Ag, AT-III and PC antigen levels were significantly increased in the LA-positive patients as compared with LA-negative patients. These changes indicate both vascular endothelial cell damages and a compensatory increase in coagulation inhibitors in the LA-positive patients.

Adult↗
PubMed1990

[Decrease of hearing acuity from use of portable headphones].

The association between headphone use and hearing acuity was studied among 155 medical students aged 22-29 years. Hearing levels were measured and subjects were classified into three groups: A: n = 14), off-line or portable headphone users (group B: n = 16), and the control group. Past or present headphone use frequency for group A and B is two or more times per week, with an average duration of 30-120 minutes per use. No significant differences between mean hearing acuity of the three groups were found by one-way analysis of variance. After standardization of the average hearing acuity of the control group to 0 dB, group A or B levels were plotted for each of the octave band frequencies. The mean hearing acuity at 4,000 Hz of group B showed a tendency of being lower than that of the control group. Further, percentages of group B members whose hearing acuity decreased 15, 25, 30 dB or more were significantly larger than those of the control. These results suggest that more than 10% of the young generation is at risk for damaged hearing acuity from use of portable headphones.

Adult↗
PubMed1990

[Multilocular cystic renal cell carcinoma: a report of 2 cases].

We report 2 cases of renal cell carcinoma which rarely occur as multilocular cystic masses. By means of echography, both cases were discovered as abnormal shadows occupying the middle portion of the left kidney. Using computerized tomography and selected renal arteriography, we tried to obtain an accurate diagnosis, but few specific malignant findings were gained. Finally, we made the histopathological diagnosis. In addition, we concluded by careful pathological examination that they were multilocular cystic growths. It was difficult to differentiate them preoperatively from multilocular cystic nephroma. Both patients are still alive without tumor recurrence.

Adult↗
PubMed1990

[Surgical treatment of aortic root aneurysm associating with infectious endocarditis].

From 1979 to 1989, aortic root aneurysms were encountered in 6 of the 30 patients who underwent surgical treatment for infectious endocarditis. Four patients underwent aortic valve replacement and direct or patch closure of the orifice of aortic root aneurysm. In additional 2 patients with infected aneurysm of right coronary sinus of Valsalva rupturing into the right ventricle, the aneurysm and infected tissue in the right ventricular outflow tract were completely resected and the defect of aortic sinus and VSD were closed with double Teflon fabric patches. All patients survived postoperatively, however, one patients died 1.5 months after the operation probably due to rupture of mycotic aneurysm of cerebral artery. Another late death seemed to be concerned with recurrent aortic root aneurysm, in which case direct closure of aneurysm had been performed. We believe that even if the aneurysm seems to be small, its orifice should be closed with the use of a fabric patch to prevent recurrent aneurysm formation.

Adult↗
PubMed1990

[Right ventricular myxoma complicated by paroxysmal atrial tachycardia: a surgical case report].

A rare case of right ventricular myxoma complicated by paroxysmal atrial tachycardia (PAT) is presented. A 13-year-old boy was referred to our hospital because of the recurrent episodes of PAT. Every available medical treatment was tried to reverse the PAT, during which an abnormal mass in the right ventricle was found by echocardiography. Subsequently magnetic resonance imaging computed tomography demonstrated that the tumor developed from the anterior wall of right ventricle with a pedicle. A 10 g of reddish myxomatous mass originating from the base of anterior papillary muscle was resected including the stalk during total cardiopulmonary bypass. The transient paroxysmal atrial tachycardia developed shortly after operation, however, tachycardic episode has never recurred after that. It is noteworthy that intracardiac evaluation is necessary when there is longstanding and inveterate tachyarrhythmia in otherwise healthy children.

Adolescent↗
PubMed1989

Capsaicin and its analogs inhibit the activity of NADH-coenzyme Q oxidoreductase of the mitochondrial respiratory chain.

Capsaicin and its analogs with different acyl moieties were found to inhibit the electron-transfer activity of NADH-coenzyme Q oxidoreductase isolated from beef heart mitochondria. The inhibitory potency of capsaicin was lower than those of dihydrocapsaicin and analogs with heptanoyl, capryl, undecanoyl, and lauroyl moieties, but was higher than those of analogs with palmitoyl and stearoyl moieties. The analog with the lauroyl moiety showed the strongest inhibition. These results suggest that hydrophobicity and the appropriate carbon chain length of the acyl moiety are important for the binding of compounds to the enzyme. On the other hand, capsaicin and its analogs did not interrupt rotenone-insensitive electron transfer from NADH to menadione. Furthermore, these compounds had almost no effect on the spectral properties and EPR signals arising from iron-sulfur clusters of the NADH-treated enzyme. Kinetic analyses with double-reciprocal plots showed that these compounds were competitive inhibitors with respect to coenzyme Q1, an electron acceptor. These results strongly suggest that capsaicin and its analogs bind to the coenzyme Q1 binding site of the enzyme.

Animals↗
PubMed1989

Effects of Chinese drugs "xiebai" and "dasuan" on human platelet aggregation (Allium bakeri, A. sativum).

Adenosine (1), guanosine (2), and tryptophan (3), as well as beta-sitosterol beta-D-glucoside (4) were isolated from the n-butanol-soluble fraction of Xiebai, the tuber of Allium bakeri Reg., which was recognized to have an anti-platelet aggregation effect. Moreover, 1 and 2 were also isolated from the n-butanol-soluble fraction of Dasuan, the tuber of A. sativum L. Compound 1 showed a significant inhibitory activity against both the primary and secondary wave aggregation of human platelet induced by 2 microM ADP, whereas compounds 2-4 showed no or very low inhibitory effects. The structure-activity relationships on human platelet aggregation with regard to 1, 2 and their derivatives, adenosine 2'-monophosphate (5), adenosine 5'-monophosphate (6), adenosine triphosphate (7), guanosine 3'-monophosphate (8), and guanosine 5'-monophosphate (9), and guanylyl(3'----5')adenosine (10) are discussed. Compounds 5-7 and 10 also inhibited the primary and secondary wave aggregation with a dose-dependent response.

Adenosine↗
PubMed1989

In vivo binding of the winged bean basic lectin labeled with iodo[2-14C]acetic acid to the intestinal epithelial cells of the rat.

Winged bean basic lectin was labeled with iodo[2-14C]acetic acid. The radiolabeling affected neither the antigenicity nor the hemagglutinating activity of the lectin. A liquid test meal consisting of [14C]lectin and an unabsorbable marker, [3H]polyethylene glycol (PEG), was administered to rats in order to investigate behavior of the lectin in the gastrointestinal tract. At 1 h after administration, 54% of the administered [14C]lectin was still in the stomach, 1% had reached the cecum, and 1-6% was found in the intestinal mucosa, indicating that the lectin was binding to the mucosa. In another experiment, rats were fed a commercial nonpurified diet for 3 d after administration of the test meal. About 87% of the administered lectin as well as 83% of [3H]PEG was recovered from the feces during these 3d. Lectin bound to the epithelial cells of the intestinal mucosa was recovered by liberating it from the cells with D-galactose. The recovered lectin showed both hemagglutinating activity and the antigenicity identical with those of the original lectin. These results clearly indicated that the lectin remained intact in the gastrointestinal tract while a part of it was bound to the intestinal mucosa, the rest being excreted directly into feces.

Animals↗
PubMed1989

Inotropic and chronotropic effects of N6-substituted derivatives of cyclic AMP as assessed in guinea-pig isolated right atria and papillary muscle.

1. The inotropic and chronotropic actions of N6-substituted adenosine 3':5'-cyclic monophosphate (cyclic AMP) derivatives (N6-R cyclic AMPs) were studied in guinea-pig isolated right atrial preparations and in the papillary muscle preparations from guinea-pig right ventricle. 2. All the N6-R cyclic AMPs except N6-C14H29 produced positive inotropic effects in papillary muscle. The C5H11, C6H13, C7H15, C8H17 and C9H19 compounds were the most potent as inotropic agents, the potency being lower with compounds having longer or shorter N6-side chains than these. 3. In right atria N6-C2H5-C7H15 cyclic AMPs produced negative chronotropic effects. However, after treatment of the preparations with 8-phenyltheophylline the negative chronotropic effects were either much attenuated or abolished, indicating the involvement of adenosine receptors. 4. All the N6-R cyclic AMPs except N6-C14H29 were more potent activators of bovine myocardial protein kinase than cyclic AMP. The partition coefficients between octanol and an aqueous phase of N6-R cyclic AMPs became greater as the numbers of carbon atoms increased, and there appeared to be a relationship between partition coefficient and inotropic potency. It was concluded that membrane penetrativeness rather than potency as activators of protein kinase determined the potencies of N6-R cyclic AMPs as positive inotropic agents. 5. Derivatives such as N6-C7H15 cyclic AMP, which have positive inotropic activity without any marked negative chronotropic effect, may be useful as cardiotonic agents in heart failure.

Animals↗
PubMed1989

Cadmium, NAG activity, and beta 2-microglobulin in the urine of cadmium pigment workers.

Cadmium (Cd), N-acetyl-beta-D-glucosaminidase (NAG) activity, beta 2-microglobulin (BMG), and creatinine (cr) in urine were measured during April and September 1986 in workers exposed to cadmium pigment dust (maximum exposure 3.0 micrograms/m3/8 h for respirable dust). In April and September urinary Cd ranged from 0.2 to 9.5 and from 0.5 to 7.0 micrograms/g cr with a geometric mean of 0.7 and 1.2 micrograms/g cr, respectively. The correlation coefficient between Cd and NAG was 0.261 (n = 61) in April and 0.389 (n = 50) in September. The correlation coefficient between Cd and BMG was 0.241 (n = 63) in April and 0.115 (n = 50) in September. It appears that urinary Cd concentrations have a closer relation with urinary NAG than urinary BMG, even when urinary Cd concentrations are less than 10 micrograms/g cr. It is concluded that NAG is a more sensitive indicator of Cd absorption than BMG even at urinary Cd concentrations of less than 10 micrograms/g cr.

Acetylglucosaminidase↗
PubMed1989

[Beta-blocking actions and the partial agonist activity of bopindolol, a new beta-adrenoceptor antagonist, and its two metabolites].

The beta-blocking effects of bopindolol, a new long-acting beta-adrenoceptor antagonist, and its two metabolites, 18-502 and 20-785, were studied in the isolated atria and trachea preparations of the guinea pig. The partial agonist activity (PAA) and the membrane stabilizing activity (MSA) were studied in the pithed rat and the right ventricular papillary muscle preparations of the guinea pig, respectively. Antagonistic effect of bopindolol against isoproterenol was 1.1-2.8 and 14.1 times more potent than propranolol in the atria and the trachea preparations, respectively, while those of 18-502 were 34.7-38.0 (in atria) and 29.0 (in trachea) times more potent than propranolol. beta-Blocking potencies of 20-785 were 50% (in atria) and 10% (in trachea) of those of propranolol. Bopindolol, 18-502 and 20-785 increased the heart rate of the pithed rat dose-dependently. The effects were inhibited by pretreatment of the preparation with propranolol. The onset of action of bopindolol was slower and the duration, longer than those of its two metabolites. Bopindolol and 18-502 were more potent membrane stabilizers than propranolol, while 20-785 produced only a minimal stabilizing effect. These results indicate that not only bopindolol, but also the metabolites of bopindolol, 18-502 and 20-785 are potent beta-blocking agents with PAA. It is presumed that the long duration of action of bopindolol is due to the potent activities of its metabolites 18-502 and 20-785.

Adrenergic beta-Antagonists↗
PubMed1989

[Effects of noise on sleep. Part 1. Development of an automatic analysing system for all-night sleep polygraphy by microcomputer].

In order to assess the effects of noise on sleep, the authors have developed a microcomputer system which determines the sleep stage based on an all-night EEG (electroencephalogram), rapid eye movement and an EMG (electromyogram). All the polygraphic parameters for each epoch (including spindle, rapid eye movement, alpha and delta waves, and amount of muscle tension), which are necessary to determine the sleep stage, were determined by a microcomputer using a digital data processing program. Recognition of EEG waves is based on Fujimori's method with some modifications. The rules of Rechtschaffen et al. were adopted for judging sleep stage with a slight modification. Data were obtained from six healthy students of a university. Each student was polygraphed for five to six nights under various conditions of noise exposure. Judgements of the sleep stage were made by two medical doctors. Using randomly selected 10 nights' data, the agreement between judgements by the microcomputer system and by the doctor was 77%. The percentage of agreement increased to 84% for the epochs in which the two doctors agreed. It takes about one hour to determine all-night sleep stages by this system.

Adult↗