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Biomedical subjects

S Nitta

Publications and source records attributed to S Nitta.

At least 127 records · Page 7Linked to original sources
PubMed1993

[A case of old pulmonary tuberculosis with repeated hemoptysis which presented therapeutic difficulties].

A 74-year-old male who had been infected with pulmonary tuberculosis since 1938 underwent thoracoplasty in 1955. After the operation, no symptoms manifested until 1988 when he developed hemosputum and hemoptysis in association with a cold with fever. Although he was admitted to a hospital, the symptoms could not be controlled, so he was referred to our department. The lesion causing the hemorrhage was considered to be in the upper lobe of the left lung. However, it would have been difficult to preserve respiratory function in the case of left upper lobectomy, because he had already undergone thoracoplasty on the right side. Therefore, bronchial artery embolization (BAE) using Spongel was performed. Second embolization was performed because hemoptysis referred after one month. However, the hemoptysis recurred again, so that two branches of the left subclavian artery and the left internal thoracic artery were ligated. No hemoptysis and hemosputum occurred for a while, but 2 years and 9 months after the operation, the patient was admitted due to hemoptysis with fever and coughing. Since the bronchial artery was embolized twice with spongel and twice with platinum coil, the patient's course has been good for 5 months.

Aged↗
PubMed1993

[Right ventricular myxoma with near obstruction of the pulmonary artery].

Right ventricular myxoma is very rare. To our knowledge, only 23 cases in Japan have been reported in the literature. A 76-year-old male was admitted with complaints of cough and dyspnea. We found an abnormal floating mass in the right ventricular outflow tract by echocardiography and cineangiocardiography. The digital subtraction angiography showed that the following mass continuously lodged in the pulmonary artery with total occlusion of the left main pulmonary artery and near obstruction of the right pulmonary artery. Furthermore he had the constitutional signs of myxoma and the serum IL-6 level reached 41.7 pg/ml. Under extra-corporeal circulation, we salvaged the right ventricular outflow tract to the right lung, resecting the tumor, originated from the right ventricular septum and extended to bilateral main pulmonary arteries.

Aged↗
PubMed1993

[A case of bilateral coronary artery fistulae into main pulmonary artery].

A case of coronary-pulmonary artery fistulae was presented with the review of the literature. A 46-year-old man was admitted to our department with an ischemic change in leads III, a VF on ECG. Although he had no complaint, the exercise ECG showed significant depression of ST segment in leads II, III, V4, V5. Coronary angiography revealed fistulae from left anterior descending branch to main pulmonary artery, and also from right coronary artery to main pulmonary artery. No coronary organic narrowing were found. Ligation of the fistulae was performed and postoperative course was uneventful.

Arterio-Arterial Fistula↗
PubMed1993

[A case of pulmonary solitary metastasis of renal cell carcinoma nine years after radical nephrectomy].

A 65-year-old woman was admitted to our department when a routine screening chest X-ray film demonstrated pulmonary solitary nodule. Nine years before, left nephrectomy had been performed with a diagnosis of renal cell carcinoma, and postoperative course was uneventful. Chest X-ray and CT confirmed the presence of well-circumscribed mass in the right lower lobe of lung. With a presumptive diagnosis of pulmonary metastasis of renal cell carcinoma, right lower lobectomy and resection of mediastinal lymph nodes was performed. The pathological diagnosis was metastasis of renal cell carcinoma, granular cell subtype. Pulmonary solitary metastasis of renal cell carcinoma, especially nine years after radical nephrectomy is rare case.

Aged↗
PubMed1993

[Peri- and postoperative management in one staged operation of cardiac disease combined with pectus excavatum].

Patients with pectus excavatum occasionally have coexisting surgical heart disease. During a 10-year period up to the end of 1988, we surgically treated a total of 2015 cases of pectus excavatum, including 12 cases with one staged operation for pectus excavatum and heart disease. Proving the advantage of our one staged operation for the coexisting diseases we studied data resulting from the perioperative management in the group of one staged operations (n = 5), and in the other group of single valve replacement (n = 10). Operative time, amount of operative blood loss and total amount of transfused blood, were 433 +/- 66 min. (mean +/- SD), 3180 +/- 1867 ml and 4836 +/- 2247 ml, in the former group (n = 5), respectively. These data were almost similar to those in the latter group (n = 10). Postoperative ventilatory support time and ICU stay time also showed little difference between two groups. We conclude these data supports our previous report that one staged operation has no perioperative disadvantage in the surgical treatment of patients with both cardiac disease and pectus excavatum.

Adolescent↗
PubMed1993

[Evaluation of the renal function during hypotensive anesthesia induced by nitroglycerin, prostaglandin E1 or nitroglycerin+prostaglandin E1].

We investigated the renal function perioperatively in 32 female patients who underwent mastectomy with hypotensive general anesthesia induced by nitroglycerin (NG), prostaglandin E1 (PGE1) and NG+PGE1. Urine output in PGE1 group (11 patients) was significantly larger than that in NG group (9 patients). It could be attributed to the increase of glomerular filtration rate. On the other hand, the value of beta 2-microglobulin in urine in NG group and the value of N-acetyl-beta-D-glucosaminidase in urine in NG+PGE1 group (12 patient) were abnormal in some patients. These changes were not significant, but the disturbance of renal tubule could be possible. In summary, PGE1 was effective in the maintenance of the renal function.

Adult↗
PubMed1993

Multivariate analysis of risk factors for thrombus formation in University of Tokyo ventricular assist device.

Of 77 University of Tokyo ventricular assist devices used in a total of 70 patients at 21 institutions, 13 pumps were found to have macroscopic thrombus formations. Because 19 devices that were used for less than 24 hours showed no thrombus deposition, they were considered not to have been sufficiently exposed to the thrombogenic environment for macroscopic thrombus deposition and were removed from the subsequent multivariate study. A total of eight potential risk factors were assessed in relation to thrombosis. Prevalences of thrombus formation were compared between two groups with or without each of the risk factors. In a univariate analysis, the following categoric variables were demonstrated to be significantly associated with complications, in descending order of significance: use of gabexate mesilate (protease inhibitor) as an anticoagulant (p = 0.005), normal platelet count (p = 0.010), duration of support (p = 0.038), leukocytosis (p = 0.042), and minimum pumping flow (p = 0.042). Use of heparin and the consequent increase in activated clotting time showed no relationship. Multivariate discriminant analysis, which was done to identify risk factors rejecting cross correlation between each variable, demonstrated platelet count (p = 0.006), use of gabexate mesilate (p = 0.007), and minimum flow (p = 0.008) to have significant and independent risks. These results indicate the importance of maintaining pumping flow above a certain minimum level, addition of antiplatelet drugs to the antithrombogenic regimen, and nonuse of gabexate mesitate.

Adolescent↗
PubMed1993

Dependence of baroreceptor-mediated sympathetic outflow on biventricular assist device driving frequency.

To investigate the drive condition of the artificial heart from a neurophysiological point of view, the dynamic transduction characteristics of the baroreflex system were analyzed by means of sympathetic neurograms. Two pneumatically actuated ventricular assist devices were implanted as biventricular bypasses (BVBs) in adult mongrel dogs to compare the natural heart circulation and prosthetic circulation. After BVB pumping was initiated, the natural heart was electrically fibrillated. Renal sympathetic nerve activity (RSNA) was recorded to analyze sympathetic outflow. Coherence function between the arterial pressure and RSNA was calculated to evaluate the linearity of the baroreflex system. The largest peak coherency was observed when BVB was driven at the frequency of natural heart beat prior to electrical fibrillation, which suggests that the baroreflex system shows the largest linearity at this frequency. These results suggest the possibility that the natural heart beat frequency is the setting frequency at which the baroreflex system transfers the hemodynamic rhythm to the sympathetic outflow.

Animals↗
PubMed1993

Sound spectral analysis of prosthetic valvular clicks for diagnosis of thrombosed Björk-Shiley tilting standard disc valve prostheses.

To evaluate clinical usefulness of sound spectral analysis in the early detection of prosthetic thrombosis, we analyzed specific patterns of thrombus formation in Björk-Shiley tilting standard disc prostheses in relation to the sound spectral analysis of their click sounds. Among a total of 365 Björk-Shiley tilting standard disc prostheses, nine became thrombotic. These consisted of seven prostheses in the mitral position and two in the aortic position, and the affected valves were replaced in all cases. The sound spectral analysis system includes a wide-frequency microphone and a sound spectral analyzer. To quantify the amplitude of the metallic clicks that are specific to the prosthetic valve sounds, we used a normalized maximal frequency as a diagnostic parameter for valve thrombosis. Thrombus formation was localized at the minor strut in two cases, and these demonstrated abnormally low normalized maximal frequency values only on opening clicks. In four cases thrombus formations were noted at both minor and major struts, and these showed abnormally low normalized maximal frequency values on both opening and closing clicks. In two cases with pannus formation, no abnormalities were found by sound spectral analysis. In one case, which had demonstrated abnormally decreased normalized maximal frequency values of both opening and closing clicks, the normalized maximal frequency values were normalized after thrombolytic therapy, suggesting resolved thrombosis. Reoperation, which was performed for concomitant complication of perivalvular leak, revealed no noticeable thrombus formation. The thrombi were seen on the minor strut during surgical procedures in all cases in which valve thrombosis was indicated by the sound spectral analysis. Therefore, the minor strut is considered to be the prevalent area of thrombus formation, and diagnosis could be made after observation of abnormally low normalized maximal frequency on opening clicks. We found the sound spectral analysis to be an extremely useful diagnostic tool for early detection of thrombosis in the Björk-Shiley tilting standard disc prostheses, especially because the opening clicks of the tilting disc valve were too low in amplitude for auscultation to detect the existence of mild abnormality.

Adolescent↗
PubMed1992

An automatic control algorithm for the optimal driving of the ventricular-assist device.

This paper presents a new method of keeping one of the most suitable driving conditions for regulating the outflow volume from the ventricular-assist device (VAD). The experimental results from a mock circulatory system have shown that the relationship between the stroke volume and the systolic duration of the VAD can be specified by the combination of characteristic curves of the positive and negative drive pressures. The optimal operating point on the characteristic curve have been defined as the point at which thrombosis on the blood-contacting surface and hemolysis due to mechanical damage can be avoided and at which the driving energy can be minimized. The present analysis has been revealed that the optimal operating point is the vertex of the triangular figure obtained from the characteristic curve. The algorithms for keeping the optimal operating point and for regulating the stroke volume have been also proposed.

Algorithms↗
PubMed1992

[Malfunction of prosthetic valves: pathogenesis and diagnostic measure].

Modality of the malfunction of prosthetic valve often reflects the specific features of its design and materials of the prosthesis. During past 17 years, a total of 499 cases of valve replacements were performed in our institute and among them, 50 cases received redo surgery, in which 52 prosthetic valves were replaced due to their malfunctions. Those replaced prosthetic valves were analyzed in terms of their pathogenesis, onset durations and diagnostic methods of each type of malfunction. The malfunctions included hemolytic anemia, thrombosis or tissue overgrowth and tissue failure of bioprostheses. Hemolytic anemia was experienced in 8 cases with Starr-Edwards (S-E) 2320 (n = 7) and Omni-Science (n = 1) both in the aortic position and those prostheses were replaced at 1-9.6 (mean 4.5) postoperative years (POY). The linearized rate of the complication with the S-E 2320 was 3.0%/patient-years (p-y) and its actuarial event free rate was 62% at 11 POY. Operative findings disclosed cloth wear in 5 and perivalvular leakage in 5 cases. Fourteen Hancock (H) and 3 Angell-Shiley (A-S) bioprostheses experienced tissue failure of valves and they were subjected to reoperation at 3.2-10.0 (mean 6.5) POY. The linearized rates were 4.1%/p-y for H and 4.5%/p-y for A-S with actuarial event free rates at 12 POY of 59 and 56%, respectively. Prosthetic valve thrombosis and/or tissue overgrowth were seen in 17 valves at 1.6-15.1 (mean 9.1) POY.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1992

Mayer waves in dogs with total artificial heart.

To assess the effect of a total artificial heart (TAH) on the autonomic nervous system a power spectral analysis of the hemodynamics in a TAH animal was done by the maximum entropy method. Two pneumatically driven sac-type ventricular assist devices were implanted as total biventricular bypass (BVB) in adult mongrel dogs to compare the differences between natural heart and TAH. Once the BVB was pumping, the natural heart was electrically fibrillated to constitute the BVB-type TAH model. In the arterial pressure waveform in animals with TAH, respiratory waves were not changed (97.7 +/- 24.6%) though Mayer waves were significantly decreased (47.5 +/- 22.6%) compared with the animal with a natural heart. These results suggest that prosthetic hemodynamics in the TAH animal affect fluctuations in the cardiovascular system.

Animals↗
PubMed1992

Estimation of the following cardiac output using sympathetic tone and hemodynamics for the control of a total artificial heart.

A sympathetic neurogram is potentially useful for the development of a real time total artificial heart (TAH) control system. We used sympathetic tone and hemodynamic derivatives to estimate the following cardiac output in acute animal experiments using adult mongrel dogs. Moving averages of the mean left atrial pressure and mean aortic pressure were used as parameters of the preload and afterload, respectively. Renal sympathetic nerve activity (RSNA) was employed as a parameter of sympathetic tone. Equations for the following cardiac output were calculated using multiple linear regression analysis of the time series data. A significant correlation was observed between the estimated and following measured cardiac output. These results suggest the potential usefulness of the sympathetic neurogram for the real time TAH automatic control system.

Animals↗
PubMed1992

Degree of severity of pectus excavatum and pulmonary function in preoperative and postoperative periods.

Pulmonary function was evaluated in 138 patients with pectus excavatum, paying particular attention to the degree of severity of chest deformity. We defined the severity of deformity quantitatively based upon a computed tomographic index obtained from a computed tomogram. We recognized a positive relationship between computed tomographic index (x) and percent vital capacity (y), as follows: y = 137x + 58 (n = 138, r = 0.61, p < 0.05). Pulmonary function tests were performed from 2 to 42 months postoperatively. Vital capacity decreased about 10% from the baseline value during the initial 2 months after surgical treatment and recovered to the preoperative level by 1 year after surgery. At 42 months after surgical correction, the pulmonary function was maintained at the baseline level and the severity of deformity was significantly improved. Surgical procedures for the treatment of pectus excavatum--sternocostal elevation and sternal turnover--resulted in an excellent cosmetic result but did not importantly affect respiratory function.

Adolescent↗
PubMed1992

[A rare case of mediastinal neuroblastoma with pectus excavatum in a 4-month-old boy--a surgical report].

Screening of neuroblastoma is commonly performed on 6-month-old infants; therefore, its discovery in children younger than that age is extremely rare. However, a 4-month-old boy with pectus excavatum was found to also have mediastinal neuroblastoma after close examination. This 7 kg child had no apparent symptoms, yet revealed an egg-sized shadow along the right atrium in the chest X-ray film, and along the right side of the vertebrae on CT. Due to the increase in the size of the tumor after two months of observation, we suspected malignant neurogenic tumor and performed a thoracotomy. With a right posterolateral thoracotomy we removed the dark-brown, elastic tumor measuring 6 x 4 x 3 cm and located along the right side of the vertebrae from III through VIII ribs. The origin was the thoracic sympathicus and the pathological diagnosis of the tumor was neuroblastoma with rosset formation. After conducting a post-operative chemotherapy (Jame's protocol), no evidence of recurrence was observed at 33 months after surgical treatment. We summarized the previously reported seven surgically treated cases of Stage I mediastinal neuroblastoma at less than 12 months of age. Among the 2500 pectus excavatum surgeries that have been held at our department, non has been found to have mediastinal neuroblastoma.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1992

Cardiac-related sympathetic nerve activity during circulation with only the left ventricular assist device.

Circulatory maintenance with a left ventricular assist device (LVAD) alone during cardiac arrest until heart transplantation has been evaluated. To assess the effect on the autonomic nervous system, the sympathetic neurogram was analyzed by power spectrum and coherence function. LVAD were inserted between the left atrium and the descending aorta in seven adult mongrel dogs and ventricular fibrillation was induced electrically. Renal sympathetic nerve activity (RSNA) was detected by bipolar electrodes attached to the left renal sympathetic nerve. Values of squared coherence between the arterial pulse wave and RSNA were calculated. Under the condition of circulatory maintenance with only LVAD, coherence at the cardiac rhythm frequency was decreased, and coherence at the LVAD pumping rhythm frequency was increased. These results indicate that the arterial pulse wave observed during maintenance of the circulation with only LVAD contributed to the sympathetic neurogram.

Animals↗
PubMed1991

[Salivary testosterone levels in normal boys at puberty].

Salivary testosterone (Salivary-T) was measured in 133 normal boys at puberty (8-14 years old) and 21 adult males (24-36 years old) by using radioimmunoassay. Also, a simultaneous measurement was performed on salivary-T and serum total testosterone (Total-T) and free testosterone (Free-T) in order to study the correlation between saliva and serum. The results were summarized as follows: (1) Good correlations were observed in the values between Salivary-T and Total-T or Free-T. The correlation coefficient value was 0.54 between Salivary-T and Total-T, 0.84 between Salivary-T and Free-T when measured by DPC kit. Correlation coefficient value was 0.59 between Salivary-T by Wien kit and Total-T by DPC kit, also 0.77 between Salivary-T by Wien kit and Free-T by DPC kit. (2) Salivary-T, in the mean level, increased by age. The most rapid increase of Salivary-T was observed at 13 years of age. (3) Diurnal change of Salivary-T was observed at 13 years of age through adult age. Salivary-T level was highest in the morning and declined toward evening. (4) These results suggest that Salivary-T measurement was highly reliable and applicable for use in the monitoring of androgen status.

Adolescent↗