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K Hirosawa

Publications and source records attributed to K Hirosawa.

At least 91 records · Page 5Linked to original sources
PubMed1987

Light microscopic observations of the vomeronasal organ of Habu, Trimeresurus flavoviridis.

Light microscopic observations of the vomeronasal organ (VNO) (Jacobson's organ) of Habu, Trimeresurus flavoviridis, revealed that the organ was encased in the os vomeris and the vomeronasal cartilage on either side of the nasal septum. Habu VNO was divided into a dome-shaped portion mainly composed of a sensory epithelium (SE) and a hemispherical mushroom body covered with a ciliated epithelium. A narrow lumen, leading to the oral cavity via the vomeronasal duct, was made between the mushroom body and the SE. The SE consisted of a supporting cell layer facing the lumen and the underlying sensory cell layer where a large number of cells piled up in columns. Vascular plexuses were found around the neck and bottom of the columns. Along the antero posterior axis of the VNO, the height of the columns reached its maximum in the middle of the dorsal and the median parts (over 300 micron), and gradually decreased toward lateral. Each column contained undifferentiated basal cells, sensory cells and satellite cells. Sensory cells had a round nucleus and prominent lipofuscin granules. The sensory cells were arrayed in a string-like arrangement. Cells situated in the neck region of columns contained a larger amount of lipofuscin granules. Distal processes of sensory cells passed through the cytoplasmic meshwork of supporting cells and terminated as small swellings. Aggregates of heterogeneous cell populations were observed in the antero lateral region of the dome. A number of pigment cells were seen in the epineurium and the perivascular regions of the dorsal and lateral VNOs. Goblet cells were present in the lateral boundary between the dome portion and the mushroom body. Present findings clarify the complex organization of the Habu VNO, and the occurrence of the sensory columns similar to those reported in other snakes.

Animals↗
PubMed1986

Microanalysis of free fatty acids in plasma of experimental animals and humans by high-performance liquid chromatography.

A high-performance liquid chromatographic (HPLC) method was developed for microanalysis of thirteen free fatty acids using 200 microliter of plasma. Fatty acids were derivatized with 9-anthryldiazomethane for HPLC analysis. Use of an ODS minicolumn for pretreatment of plasma gave a more accurate determination of free fatty acids in plasma than by chloroform extraction. Using this method, thirteen free fatty acids in the plasma of normal human, dog, rabbit, guinea pig and rat were determined.

Animals↗
PubMed1986

Idiopathic sustained ventricular tachycardia responsive to verapamil: clinical electrocardiographic and electrophysiologic considerations.

Fifteen cases of idiopathic VT responsive to verapamil were studied to examine its clinical, electrocardiographic and electrophysiologic features. All patients were male, aged 15-49, average age 28. Initial onset of VT occurred at ages 9-48 (average 21). Time from onset of VT to first admission was 1-20 years (average 8.2 years), and patients had been followed for 17-40 months (average 27 months). 13 cases had palpitations, 5 had faintness, 1 had syncope, but no deaths were reported. ECG's at time of VT exhibited CRBBB + LAD pattern in 12 cases, CRBBB + RAD pattern in 1, and LBBB in 2. VT rate was 130-200 bpm (average 163 bpm), with QRS width of 0.11 - 0.16 sec (average 0.14 sec). ECG's during sinus rhythm revealed no ST/T abnormalities, although in 6 cases they were found post-VT. 5 cases had recognizable H waves during VT, and HV intervals were shorter than that during sinus rhythm. VT could be induced by programmed electrical stimulation in 14 cases. VT or RVR could be induced by atrial pacing in 6 of 14, single RV extra-stimuli in 12 of 14, paired pulses in 5 of 12, RV overdrive pacing in 7 of 14, and burst pacing in 6 of 14 cases. VT could be terminated by RV burst pacing in 14 of the 15 cases, while single RV stimuli were effective in 5 out of 12 cases. Among the 12 cases in which VT could be induced by single RV extra-stimuli, the relationship between changes in premature interval for the induction of VT and the echo interval of VT (extrastimulus to first VT complex) was examined. 8 showed an inverse relationship, 3 showed a concordant relationship and 1 case could not be assessed. An inverse relationship was found between changes in paced cycle length and echo interval for the 2 cases in which VT could be induced by rapid pacing. Verapamil terminated sustained VT in 12 out of 13 cases, and in another case had a pronounced decelerating effect. Prior to termination, VT rate was drastically reduced (from 163 +/- 29 bpm to 128 +/- 29 bpm). Verapamil was able to prevent the induction of VT in 6 out of 14 cases, while in 6 cases the VT zone was expanded and in 2 cases the VT zone was narrowed.(ABSTRACT TRUNCATED AT 400 WORDS)

Action Potentials↗
PubMed1986

Analysis of histopathologic findings in cases with dilated cardiomyopathy with special reference to formulating diagnostic criteria on the possibility of postmyocarditic change.

From our study employing serial endomyocardial biopsy in patients with acute viral or idiopathic myocarditis, we were able to construct histopathologic criteria for acute, subacute and convalescent myocarditis. We realize that it is difficult for the inexperienced observer to make an appropriate diagnosis of myocarditis or postmyocarditic changes in patients with dilated cardiomyopathy (DCM). In order to overcome this problem, each finding was graded and the scores obtained were analyzed statistically and compared with those from hypertrophic cardiomyopathy (HCM) and chronic right ventricular overloading (CRVO). The scores were obtained by summing the gradings for each of the following findings: increase of fibrocytes, increase of fibroblasts in the interstitium, hypertrophy of myocytes, fragmentation of muscle bundles, interstitial fibrosis, disarrangement of muscle bundles, abnormal branching, variation in size, increased glycogen deposition in the sarcoplasm, scarcity of myofibrils, and nuclear degeneration of myocytes and endocardial thickening. Since the increase in number of fibrocytes was considered important, its value was doubled. Scores in each group were as follows: convalescent myocarditis: 17.1 +/- 4.7 (n = 10), DCM: 13.2 +/- 3.3 (n = 47), HCM: 9.7 +/- 2.4 (n = 20), CRVO: 7.0 +/- 3.6 (n = 21). It was found that the scores for cases with myocarditis in the convalescent stage and in DCM were higher than those found for cases with either HCM and CRVO (p less than 0.05). In summary, the high score for postmyocarditis in DCM could suggest that prior myocarditis is an important causative factor of this disease.

Biopsy↗
PubMed1986

Long-term management of bradyarrhythmias following open heart surgery: surgical A-V block and sick sinus syndrome after surgery for secundum atrial septal defects treated with permanent cardiac pacing.

Postoperative clinical findings from 25 patients with surgical A-V block and 12 with SSS following surgery for ASD who received permanent pacemakers were analyzed in order to consider the long-term management of postoperative bradyarrhythmias. Surgical A-V block: Episodes of Adams-Stokes were observed in 11/25 patients before pacemaker implantation, and in 6 of these (55%) the onset of episodes occurred more than a year after open heart surgery. Of 8 cases for which ECG's during Adams-Stokes were available, 2 had bifascicular or trifascicular block which progressed to complete A-V block below the His bundle. The 6 others (75%) had ventricular tachycardia or ventricular flutter-fibrillation during Adams-Stokes. 2 of these had blocks above the His bundle. 4/25 had improvement of complete A-V block within a month. Following pacemaker implantation, 3 died of heart failure and 3 of sudden death. 5 year survival was 70%. Therefore, surgical A-V block requires careful long-term management, and the presence of ventricular tachyarrhythmias as well as the location of block are important predictors of patient risk. SSS after surgery for ASD: 10/12 patients had Adams-Stokes, of which 6 (60%) had initial onset over 5 years after surgery, and 9 had paroxysmal atrial flutter and fibrillation which coincided with the onset of Adams-Stokes. 3 of 7 patients (42%) for whom preoperative ECG's were available had sinus bradycardia. Thus, SSS after ASD surgery may be preceded by preoperative deterioration of sinus node function and succeeded by late onset of Adams-Stokes, necessitating pre- and postoperative assessment of sinus node function. The presence of atrial tachyarrhythmias also serves as an important indicator of the severity of SSS after ASD surgery. The onset of Adams-Stokes varied by patient over a wide range of time, emphasizing the need for careful long-term follow-up. Clinical symptoms and prognosis were affected by tachyarrhythmias as well as the severity of the bradycardia. Therefore, the presence of ventricular/atrial tachyarrhythmias is an important factor in the long-term management of postoperative bradyarrhythmias.

Adams-Stokes Syndrome↗
PubMed1986

Electron microscopic observations of Descemet's membrane of peripheral cornea.

The posterior portion of the Descemet's membrane was studied by scanning and transmission electron microscopy; the materials comprised 87 human peripheral corneas with ages from 2 to 98 years, 5 monkey corneas and 4 rabbit corneas. In some specimens, the endothelium was removed by ultrasonication. After removal of the endothelium, "curly structures" were recognized on the surface of the Descemet's membrane, where the membrane showed a gradual thinning. These structures appeared along the whole circumference of the cornea with variable width in the human specimens, but in monkey and rabbit corneas, the extent of these structures was less than in the human cornea. The "curly structures" were not encountered in young subjects, and they increased with age. There was a positive correlation (r = 0.60, P less than 0.001) between the age and the extent of these structures. Other aging products of the Descemet's membrane, ie, Hassall-Henle bodies, were partly surrounded by the "curly structures". The human "curly structures" consisted of collagen fibrils, halo structures in the collagen bundles, wide-spacing fibers, microfibrils, ground substances containing minute filaments and a structure resembling the Descemet's membrane. Components of "curly structures" of the monkey and rabbit were almost the same as those of the human except for the Descemet's membrane-like structure.

Aging↗
PubMed1986

[Doppler evaluation of porcine mitral valve dysfunction].

Seventy patients with bioprosthetic mitral valve were examined to study the applicability of the Doppler techniques including pulsed, continuous wave and color Doppler echocardiography in diagnosing and evaluating the severity of prosthetic valve dysfunction. The study population consisted of 70 patients who underwent mitral valve replacement (45 patients with Hancock valve, 13 with Angell-Shiley valve, 10 with Carpentier-Edwards valve). The dysfunctions were transvalvular regurgitation in 20 instances and paravalvular regurgitation in three, all of which were confirmed at surgery. A control group of 47 patients with the normally functioning porcine prosthetic mitral valve were also studied. Diastolic transmitral flow patterns were recorded from parasternal and apical approaches using color Doppler echocardiography, and the direction of the flow was definitely identified on the flow image. Transmitral flow signals spread from the mitral orifice to the mid-portion of the interventricular septum, and its direction was perpendicular toward the mitral ring in all cases. Flow velocity patterns in the left ventricle and atrium were recorded in the apical long-axis view of the left ventricle or apical four-chamber view using pulsed (high pulse repetition frequency) and continuous wave Doppler techniques. Two dynamic alterations in patients with the porcine mitral valve were evaluated from 1) the peak velocity and pressure half time (PHT) of transmitral flow in early diastole, and 2) the regurgitant jet in the left atrium indicating transvalvular or paravalvular regurgitation. The results were as follows: 1. Normally functioning porcine mitral valves were characterized by peak velocities (PV) less than or equal to 1.82 (mean +/- SD 1.44 +/- 0.27) m/sec and PHT less than or equal to 180 (mean +/- SD: 135 +/- 30) msec. In 23 patients with prosthetic valve dysfunction documented at surgery, peak velocity (mean +/- SD 2.23 +/- 0.19 m/sec) was significantly greater (p less than .001) than that of patients in the normally functioning prosthetic valves, and PHT ranged from 135 to 340 msec (mean +/- SD: 226 +/- 81 msec). 2. Among the 23 patients with porcine valve dysfunction, a harmonic striped pattern were recorded at the mitral valve levels in eight patients. All these patients had a musical murmur, and their peak velocity was more than 2.0 m/sec, but the PHT was less than 180 msec in seven patients. In these patients, valvular tears without calcification were confirmed at surgery.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1986

[Prognosis of dilated cardiomyopathy: an integrated study using a prognostic index].

A ten year follow-up study of 111 patients with dilated cardiomyopathy (DCM) was conducted. The five year survival rate after onset of subjective symptoms was 53%; the ten year survival rate, 22%. To evaluate the prognosis of DCM, the cardiothoracic ratio (CTR), ECG, hemodynamics, and histopathological contractility failure index (HCFI) which we constructed via a right ventricular endomyocardial biopsy, were compared. Patients having malignant arrhythmias with mildly impaired cardiac status, mild cardiomegaly and low HCFI were more prone to sudden death. In patients with progressively deteriorating cardiac status, refractory cardiomegaly, supraventricular arrhythmias, left axis deviation, prolongation of QRS interval, low voltage and high HCFI, the cause of death was more likely refractory heart failure. A prognostic index of DCM was then constructed through cardiac status, CTR, ECG, hemodynamics and HCFI. The mortality rate of the group with a prognostic index of seven points or below was 5.0%; the group with eight points or above was 82.1%. The prognostic index of DCM was thus shown to be a useful prognostic indicator.

Adult↗