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Biomedical subjects

T Kanazawa

Publications and source records attributed to T Kanazawa.

At least 163 records · Page 9Linked to original sources
PubMed1990

Selective effect of KB-2796, a new calcium entry blocker, on cerebral circulation: a comparative study of the effects of calcium entry blockers on cerebral and peripheral arterial blood flows.

The effects of a new calcium entry blocker, KB-2796, on cerebral and peripheral circulation were compared with those of four other calcium entry blockers (flunarizine, cinnarizine, nicardipine, and diltiazem) and also papaverine in anesthetized dogs. KB-2796 increased the vertebral blood flow to the same extent as the other drugs. KB-2796 and the other drugs increased the coronary blood flow, although the effect of KB-2796 was obviously weaker than that of the other drugs. The dose of KB-2796 producing a 30% increase in coronary blood flow was about 20 times higher than that producing an equivalent increase in vertebral blood flow. KB-2796 and the other calcium entry blockers caused a moderate increase in both femoral and common carotid blood flow. The renal artery showed a biphasic response to all drugs, which consisted of an initial decrease and a subsequent increase in the flow. From these results, it is suggested that KB-2796 is a new type of calcium entry blocker that selectively affects the cerebral circulation. It is also concluded that calcium entry blockers have a different spectrum of vasodilatory action on coronary and cerebral vascular beds and that a selective coronary vasodilatory action is not a common feature among all calcium entry blockers.

Animals↗
PubMed1990

Acceleration of platelet aggregability due to modulation of native LDL.

The aim of this experiment was to clarify whether low density lipoprotein (LDL) causes an acceleration of platelet aggregability. Native LDL was separated into two fractions by filtered tap-water dialysis, namely, water-soluble LDL (WS-LDL) and non-water-soluble LDL. Although native LDL did not enhance the platelet aggregability, WS-LDL made it markedly increased. WS-LDL consisted of the lipid constituents that were not found in native LDL. Namely, in thin-layer chromatography of WS-LDL, an unknown spot between triolein and free fatty acid was clearly stained. This unknown spot in the WS-LDL was produced by the peroxidation of cholesteryl ester in native LDL. It was confirmed that the spot has the same Rf value as the peroxidate of cholesteryl linolate in thin-layer chromatography. If native LDL is modulated by divalent metal ions and oxygen in the fluids, LDL with biological activity such as an increase of platelet aggregability is produced.

Chromatography, Thin Layer↗
PubMed1990

Changes in vascular wall production of prostacyclin and thromboxane A2 in spontaneously hypertensive rats during maturation and the concomitant development of hypertension.

The purpose of this study was to clarify how the metabolism of vascular prostacyclin (PGI2) and thromboxane (TX) A2 in spontaneously hypertensive rats (SHR) is involved in aging and development of hypertension. We removed the aortic walls from 5-week-old and 20 to 25-week-old SHR and age-matched Wistar Kyoto rats (WKY). At 5 weeks of age, there was no significant difference in basal and maximal (arachidonic acid 0.1 mM) 6-keto-PGF1 alpha production between SHR and WKY, but the TXB2 generation in the SHR aortic wall was markedly enhanced as compared with that in WKY. At 20 to 25 weeks of age, the SHR aortic wall synthesized about 1.5 times more 6-keto-PGF1 alpha in the basal condition and twice as much as in the maximal condition as did the WKY wall. However there was no significant difference in TXB2 production between SHR and WKY. Age-dependent increase of vascular 6-keto-PGF1 alpha was greater in SHR than in WKY. Moreover, the maximal/basal 6-keto-PGF1 alpha production ratio increased with age in SHR, but not in WKY. The synthesis of vascular TXB2 was enhanced with age in WKY, but did not change with age in SHR. These data suggest that not only the enhanced basal generation of vascular 6-keto PGF1 alpha but also a much greater reservoir of 6-keto-PGF 1 alpha synthesis in SHR was induced by both hypertension and maturity. The increased production of vascular TXB2 in young SHR may affect the development of hypertension.

6-Ketoprostaglandin F1 alpha↗
PubMed1990

[Experience with extracorporeal shock wave lithotripsy for urinary stone. Factors for requiring more than two ESWL treatments and its result].

Extracorporeal shook wave lithotripsy (ESWL) was performed for the treatment of 1277 urolithiasis patients at Osaka City University Hospital from July, 1985 to December, 1988. A total of 1788 ESWL treatments were carried out using Dornier HM3 kidney lithotripter. 964 patients (75.5%) underwent only one ESWL treatment, while 313 patients (24.5%) more than two ESWL treatments. We retrospectively examined the factors for requiring more than two ESWL treatments. Not only stone number, size and location, but fragility were considered to be the main causes for requiring more than two ESWL treatments. According to component analysis of ureteral stones, which were hard and resistant to shock wave, calcium apatite content of these stones turned out to be high (p less than 0.001). As for fragility, the residual stones created by ESWL were more difficult to be disintegrated that the nontreated stones of the same size (p less than 0.05). "Fragility" of the stones before shock wave and residual stones after ESWL are considered to be a major problem in ESWL treatment of urinary stones to be solved in the years to come.

Adolescent↗
PubMed1990

Epidemiological study on hypertension in northern Japan.

Aging for 5 years, from 50 to 55 years of age, influenced the various markers in a normotensive group but a similar correlation could not be seen in a hypertensive group. This suggests an impaired control of physiological homeostasis in hypertensive subjects. An increase in body mass index (BMI) is an important predictor in understanding the pathogenesis of hypertension, although the mechanism is uncertain. A reduction in BMI may reduce the risk of high blood pressure.

Age Factors↗
PubMed1990

Scanning electron microscopic observations of microcanals and continuous zones of interglobular dentin in human deciduous incisal dentin.

Scanning electron microscopic (SEM) observation of the coronal dentin of deciduous incisors revealed microcanals and continuous zones of interglobular dentin (CID) in the labio-lingual central portion of dentin beneath the incisal edge. The microcanals, which were clearly larger than dentinal tubules, extended from the incisal edge to the vicinity of the pulp cavity. They were located essentially in the labio-lingual central portion of the dentin and were arranged linearly in the mesio-distal direction. Inside the microcanals, collagen fiber bundles were arranged almost in parallel with the canal long axis: spherical bodies 1.0-2.5 microns in size made up of assemblies of regular parallelpipedal crystals and granulated crystals were also seen. In some instances, bacteria had invaded incisal dentin that had been exposed by attrition. The CID were made up of interglobular dentin aligned with the long axis of the tooth. As was true in the case of the microcanals, several zones were arranged irregularly in the mesio-distal direction, generally in the labio-lingual central portion of the coronal dentin. The CID were confined to about half the width of the incisal edge dentin on the incisal edge side and did not appear in the vicinity of the pulp cavity. Within the interglobular dentin itself, which was surrounded by calcospherites, were longitudinal collagen fibers connected with dentinal tubule walls inside calcified dentin and collagen bundles forming a network with those fibers. Spherical bodies 1.0-1.5 microns in size were observed attached to the surfaces of the bundles or distributed among these fibers. In some instances, the microcanals penetrated the CID.

Child↗
PubMed1990

[Influence of ventriculoatrial conduction on hemodynamic consequences in patients with artificial pacing].

To assess the hemodynamic consequences associated with ventriculoatrial (VA) conduction following pacemaker implantation, 22 subjects with the sick sinus syndrome were studied using two-dimensional echocardiography (2DE) and Doppler techniques, including pulsed Doppler (PD). Pacemakers used were unipolar, programmable pulse generators which can operate in the DDD and VVI modes. A simultaneous strip chart recording of 2DE, phonocardiogram and ECG was obtained in each mode. Systolic time intervals (STI) and left ventricular diameters were measured using 2DE. Left ventricular ejection time (LVET) was determined from the aortic valve echo, which was the interval between the opening and closure of the cusp. Left ventricular pre-ejection period (LVEPEP) was the interval between the Q wave of the ECG and the opening of the aortic valve. Right ventricular (RV) STI were also measured using the pulmonary valve echo in a manner similar to that used with the aortic valve echo. Stroke volume and ejection fraction were calculated by conventional methodology. RVET was longer than LVET; RVPEP was shorter than LVPEP. These two STIs were shortened using an incremental pacing rate in each mode. Similarly, the stroke volume and ejection fraction decreased, depending on the pacing rate at a range of 50-110 b/min. RVET and LVET in DDD were longer than those in VVI. RVPEP and LVPEP in DDD were shorter than those in VVI. Stroke volume and ejection fraction in DDD were smaller than those in VVI. There was a significant difference (p less than 0.05) between DDD and VVI. These differences became significantly (p less than 0.01) greater between DDD without VA conduction and VVI with VA conduction.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1990

[Evaluation of the results of extracorporeal shock-wave lithotripsy (ESWL) for solitary upper urinary tract stone].

At Osaka City University Hospital, we performed extracorporeal shock-wave lithotripsy (ESWL) for 1277 patients in a total of 1788 sessions using Dornier kidney lithotripter Model HM III from July, 1985 to the end of December, 1988. Among the patients with a solitary stone, 911 cases were available for the follow-up study and we have compared the results among these cases in respect to the stone location and size. The results obtained were as follows: the ratio of kidney stone to ureter stone was found to be 2.2:1 in male, and 3.8:1 in female patients. This indicates that ureter stones are more frequently found in male than in female patients. In addition, we compared the size of kidney stones found in the patients including 415 male and 243 female patients. Stones larger than 20 mm were more frequently found in female than in male patients. Moreover, a stone composition study of these patients showed that the contents of both phosphate calcium and magnesium ammonium phosphate were higher in female than in male patients. ESWL performed against stones at pelvis and calyces exhibited the best results. The results obtained with the stones less than 20 mm in diameter were especially favorable with a success rate of 100% for the stones less than 10 mm and 83% for the stones 10-20 mm, in diameter, while the results with the stones larger than 20 mm in diameter were rather poor with a success rate of 31%. ESWL performed against ureter stones showed poor results with a success rate of 63% for the stones smaller than 20 mm in diameter.

Calcium Phosphates↗
PubMed1990

[Effect of a spacer device used with metered dose inhaler].

Metered dose inhaler (MDI) is widely used in treatment of bronchial asthma. But adequate efficacy is not obtained if the patients use an improper technique of inhalation. The spacer device was designed to reduce such inhalation errors. Three types of spacers (pear type, tube type, paper spacer) were studied to confirm their usefulness in bronchial asthma. Bronchodilating effect of procaterol (10 micrograms/puff X 2) in conventional MDI or MDI with a spacer was evaluated. There were no significant difference in the effect on the pulmonary function after single inhalation of MDI with or without a spacer for 60 minutes. In regular use of MDI with a spacer for two weeks, PEFR and FEV1.0 were slightly improved. These results suggest that effect of MDI with a spacer may be more effective than MDI alone in regular use.

Administration, Inhalation↗
PubMed1990

Electron microscopic findings in benign deoxycorticosterone and 11-deoxycortisol-producing adrenal tumor.

The ultrastructural characteristics of a benign adrenal adenoma that produces deoxycorticosterone and 11-deoxycortisol were examined by transmission electron microscopy. Both large, round mitochondria with a few cristae in the peripheral portion and spherical or oval mitochondria with sacrotubular cristae were observed in adenoma cells. The development of agranular or granular endoplasmic reticulum varied from cell to cell. In some cells, many vacuoles and collagenous fibers were also seen. Thus, the adrenal tumor we examined was composed of the cells derived from the fascicular zone, which are associated with Cushing's syndrome, and the cells of the glomerular zone observed in association with primary aldosteronism.

17-Hydroxycorticosteroids↗
PubMed1989

Changes in the steady-state fluorescence anisotropy of N-iodoacetyl-N'-(5-sulfo-1-naphthyl)ethylenediamine attached to the specific thiol of sarcoplasmic reticulum Ca2+-ATPase throughout the catalytic cycle.

Cys674 of the sarcoplasmic reticulum Ca2+-ATPase was selectively labeled with N-iodoacetyl-N'-(5-sulfo-1-naphthyl)ethylenediamine without a loss of the catalytic activity, and the steady-state fluorescence anisotropy of this label and its total fluorescence intensity were followed throughout the catalytic cycle. At 25 degrees C, the anisotropy and the total fluorescence intensity increased by 2.1 and 9.4%, respectively, upon Ca2+ binding to the high affinity sites. Upon subsequent ATP binding to the catalytic site, the anisotropy and the total fluorescence intensity decreased by 6.8 and 23.9%, respectively. These drops likely occurred in the enzyme.ATP complex. The extents of changes upon additions of Ca2+ and ATP in the anisotropy, but not in the total fluorescence intensity, were greatly reduced by lowering the temperature. Slight drops in the anisotropy and the total fluorescence intensity occurred upon conversion of phosphoenzyme (EP) from the ADP-sensitive form to the ADP-insensitive form. The anisotropy and the total fluorescence intensity returned to the initial level when EP was hydrolyzed. Mg2+-dependent Pi-induced drops in the anisotropy and the total fluorescence intensity occurred coincidently with EP formation from Pi. These demonstrate that the ATP-induced drops in the anisotropy and the total fluorescence intensity are predominant throughout the catalytic cycle. Most probably, the changes in the anisotropy are due to changes in the rotational diffusion of the label. These findings indicate that ATP binding to the catalytic site induces a relaxed conformation in the microenvironment of the label bound to Cys674.

Adenosine Triphosphate↗
PubMed1989

Technique for superimposing a color slide onto a facial cast to sculpt a facial prosthesis.

A precise and uncomplicated technique for superimposing a color slide onto a facial cast for sculpting a facial prosthesis of the periorbital region is described. This technique allows making a facial impression with the eye closed. The superimposed slide in full-face and profile views provide a natural appearance to the facial cast. Properly selected dental and photographic materials are essential to the success of this imaginative procedure.

Humans↗
PubMed1989

Two years clinical experiences with extracorporeal shock-wave lithotripsy and transurethral ureterolithotripsy for ureteral stones at Osaka City University Hospital.

From July 1985 to June 1987, 303 patients with ureteral stones were treated by either extracorporeal shock-wave lithotripsy (ESWL) or transurethral ureterolithotripsy (TUL). The ureteral stones were classified into two groups, upper and lower ureteral stones. The upper ureteral stone was defined as a stone located above the pelvic brim in radiological examinations. ESWL was performed using a Dornier lithotriptor HM-3. For TUL, following the insertion of a guide wire and dilatation of the intramural ureter by ureteral bougie, a ureteroscope was introduced into the ureter. The success rate included both patients who became stone free and patients whose stones were disintegrated into less than 4 mm. The success rate of ESWL for upper ureteral stones was 90%, and 8.5% were treated subsequently by TUL. The success rate of TUL for upper ureteral stones was 42%, and the remaining required another session of TUL or another procedure, mainly ESWL. On the other hand, the success rate of TUL for lower ureteral stones was 71%, and the remainder also required another session of TUL or another procedure, mainly ESWL. The efficacy of TUL for stone street was comparably low by the evaluation done at 5 days after the procedure. However, almost all patients with stone street, which had developed after ESWL treatment, became stone free several weeks after TUL and insertion of a stent catheter. Major complications or side effects for ESWL were fever of more than 37.5 degrees C (7.5%) and pain attacks (8.9%).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

The protection of the acute ischemic myocardium: merits and demerits of the coronary reperfusion.

At first, in order to know the causes of reperfusion injury, we studied myocardial injury by reperfusion in comparison with by Ca overloading, and the salvage of the myocardium from reperfusion and from Ca overloading by Ca antagonist, diltiazem (DIL), in 52 anesthetized open-chest dogs. In myocardial mitochondria (Mit), Ca content was increased and Mg content and oxidative phosphorylation (State III) were decreased both by 120 min reperfusion after 60 min occlusion and by Ca overloading. Ca and Mg contents and oxidative phosphorylation of Mit were similarly changed by reperfusion as by Ca overloading. Electron-microscopically, myocardial injury by Ca overloading resembled reperfusion injury. Therefore, Ca inflow to myocardial cells may be one of the determinant factors which induce reperfusion injury. Although myofibrils were disorganized and contraction band necrosis appeared in these two types of myocardial injury, amorphous densities and glanular densities which indicated the irreversible injury of Mit appeared only in reperfusion injury. Then, the myocardial injury by Ca overloading is suspected of being mainly composed of the injury of myofibrils. The myocardial injury by reperfusion and by Ca overloading was prevented by DIL. These facts suggest that DIL may suppress Ca inflow and Mg outflow to myocardial cells. Second, to know the effect of positive inotropic agents on pump failure in acute myocardial infarction, we studied the effect of dobutamine (DOB) on the ischemic myocardium and the salvage of the ischemic myocardium from DOB-induced injury by DIL in 39 anesthetized open-chest dogs. After occlusion, the regional mechanical function of the acute ischemic myocardium was rapidly lost and % systolic shortening was negative level. In this situation, myocardial Pco2 quickly increased and myocardial pH rapidly decreased. These parameters reached peak level after 20 min occlusion. Then, paradoxical improvement phenomenon appeared so that Pco2 decreased and pH increased after that. Myocardial blood flow measured by thermocouples was stable at almost 10% of the preoccluded level for a 90 min occlusion. These data suggest that anaerobic metabolism and residual aerobic metabolism can not supply the ischemic myocardium with enough energy and that irreversible injury may appear in the ischemic myocardium.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

[Case of the maxillofacial defect patient. Prosthetic treatment after reconstruction of the palate and face using deltopectral flap].

The patient, a 72-year-old edentulous man, had an extensive maxillofacial defect caused by treatment of the maxillary cartinoma. As his left maxillary and zygomatic bone, a portion of the soft palate, orbital cavity contents and soft tissues of the cheek had been excised, his face was ugly, and his speech and eating were extremely poor. For this patient, first of all, plastic surgeons reconstructed the cheek and palate using deltopectral flap. Secondly, dentists prepared a facial prosthesis and a set of complete dentures. Four months after prosthetic treatment, plastic surgeons corrected the left corner of the mouth using temporal muscle flap and fascia lata, and strengthened infraorbial region of deltopectral flap by grafting the left 5th rib. Lastly, dentists remade the facial prosthesis. As a result, the patient had great improvement in his face, speech and eating. Periodic examination of the surgical site can be practiced through the remaining facial defect. The advantages of the surgical reconstruction in this case were as follows. (1) As reconstruction of the cheek narrowed a facial defect, it was easy to improve patient's appearance by a small facial prosthesis. (2) The closure of the palate was effective to improve hypernasal speech, to prevent fluid leakage into the nasal cavity and to improve the retention and stability of the upper complete denture.

Aged↗
PubMed1989

[Studies on the retentive force of clasps. 1. An effect of the material and technician].

Wire clasps and cast clasps are the most common retainers for removable partial dentures. The purpose of this study was to investigate the differences in the material and the variation among individual technicians in the retentive force of both clasps. The clasps were made in accord with the clinical method for experimental metallic model of the left mandibular second premolar and the retentive force of each clasp was measured by a pull-out test. The results were as follows: 1. Both types of clasp showed a large variation in the retentive force among the technicians, but no particular tendency was observed in the differences between wire and cast clasps. 2. There was no significant difference between the two types of clasp in the retentive force. 3. Due to the differences in individual technical skills, it seems to be difficult to make wire clasps with a standardized retentive force.

Denture Design↗