Biomedical subjects
Publications and source records attributed to T Omoto.
The case was a 54-year-old man after orthotopic heart transplantation with infected pseudoaneurysm of the ascending aorta. The operation was performed with hypothermic circulatory arrest. Pseudoaneurysm was excised and aortoplasty was performed with a bovine venous xenograft patch. Six months after the operation, and 2 years after transplantation, the patient is doing well.
AIM: Right ventricular (RV) dysfunction is a significant complication following implantation of left ventricular assist device (LVAD). However, RV performance after LVAD implantation remains unclear. We have studied the effects of preload and afterload on RV performance under left ventricular (LV) unloading. METHODS: Six adult mongrel dogs were subjected to cardiopulmonary bypass. RV preload and afterload were independently regulated. Dynamic pressure-length analysis of RV free walls was performed using micromanometer catheter and sonomicrometric dimension transducers. Global RV systolic function was evaluated by the relationship between stroke volume vs. end-diastolic length (EDL) or end-diastolic pressure (EDP). We also examined the afterload dependency of RV performance at constant stroke volume. RESULTS: Stroke volume vs. EDP and stroke volume vs. EDL demonstrated a linear relationship (r(2) = 0.849 +/- 0.147 and 0.776 +/- 0.121, respectively). At constant stroke volume, RV systolic peak pressure vs. EDL or EDP were shown to have a linear relationship (r(2) = 0.906 +/- 0.050 vs. 0.909 +/- 0.047, respectively). CONCLUSION: The Frank-Starling relationship for RV performance was shown in this animal model. Without interventricular interaction, RV preload is dependent on RV afterload.
An infective complication of the aorta is a potential cause of early and late mortality after heart transplantation. We report the case of a 21-year-old male cardiac transplant patient in whom a pseudoaneurysm of the recipient site of ascending aorta coincided with the site of the outflow prosthesis of a preexisting left ventricular assist device; this condition developed 9 months after transplantation.
BACKGROUND: A recurrence of bladder tumors following surgery for transitional cell carcinoma of the upper urinary tract is not rarely observed. A prospective randomized study was conducted to examine the significance of prophylactic intravesical instillation of mitomycin C (MMC) and cytosine arabinoside (Ara-C) to prevent recurrent bladder tumors after surgery for superficial transitional cell carcinoma of the upper urinary tract. METHODS: The patients were randomized into an instillation group, who received postoperative intravesical instillation of MMC (20 mg) and Ara-C (200 mg) 28 times over a period of 2 years, and a non-instillation group. The non-recurrence rate was then compared between the groups. RESULTS: Of the 27 patients registered, 25 patients (13 with instillation and 12 without instillation) were able to be evaluated, with a median follow-up period of 45 months. The non-recurrence rate of bladder tumors in the instillation group was higher than that in the non-instillation group. Although the difference was not statistically significant, the P-value (P = 0.079) demonstrated a strong trend. When any possible bias was allowed for a multivariate analysis, the difference was almost significant (P = 0.0567). No patients withdrew from this study due to any side-effects. CONCLUSION: The postoperative instillation of MMC and Ara-C may be a useful approach for reducing the recurrence of bladder tumors after surgery for upper urinary tract tumors.
Degraded carrageenan (known as poligeenan molecular weight: 20 kDa to 30 kDa) causes ulcerative colitis in experimental animals. In this paper, the molecular weight distributions of 29 samples of food-grade refined carrageenans were studied by high performance liquid gel permeation chromatography (GPC) directly connected to vacuum-ultraviolet inductively coupled plasma-atomic emission spectrometry (ICP) (GPC/ICP) as well as GPC/refractive index (RI) detection. All samples of food-grade carrageenan had a major broad peak of high molecular weight which eluted at around 6.5 min in both RI and ICP mode (sulphur and carbon), and each sample of them had no obvious peak of poligeenan (the detection limit was about 5%). The number average molecular weights of these carrageenans ranged from 193 kDa to 324 kDa, and the weight average molecular weights ranged from 453 kDa to 652 kDa based on RI data. Some samples had a few minor peaks which eluted around 10-12 min. These peaks came from ionic sulphate, sucrose or glucose. It was considered that if the data-sampling programme was improved, the GPC/ICP system would become a more powerful technique for evaluation of carrageenan samples containing ionic substances and sugar.
Little is known about the role of modified ultrafiltration in ameliorating the adverse effects of the cardiopulmonary bypass on pulmonary function in infants. Twenty-nine nonrandomized consecutive infants (<12 months of age) who underwent unrestrictive ventricular septal defect closure between 1995 and 1998 were included in this study. Down's syndrome was associated in 9 patients. The actual ventilator settings were highly homogeneous among all patients and each time point in the study. Fourteen infants received modified ultrafiltration after the discontinuation of cardiopulmonary bypass. Fifteen untreated patients served as the control group. Correlates of cardiac and pulmonary functions for both groups were compared. The arterial carbon dioxide tension in the experimental group was significantly lower than in the control group from 20 to 240 min after bypass. Arterial oxygenation and pulmonary arterial pressure were similar in the 2 groups. Modified ultrafiltration improves carbon dioxide removal after cardiopulmonary bypass in infants. This may potentially convey a beneficial impact on hemodynamics.
OBJECTIVES: Although the arterial oxygen saturation after bidirectional cavopulmonary shunting should theoretically be homogeneous if additional pulmonary flow is obliterated, the arterial oxygen saturation has been found to vary in clinical practice. Knowledge of the preoperative and operative determinants of arterial oxygen saturation early after bidirectional cavopulmonary shunting may lead to a better understanding of this unique physiology. METHODS: Thirty-five patients who underwent bidirectional cavopulmonary shunting with obliteration of additional pulmonary flow were included in this study. The arterial oxygen saturation was determined at the 5 time points over a 48-hour period. Multivariable regression analysis was used to identify the independent predictors of the arterial oxygen saturation. RESULTS: No significant interval changes occurred in the arterial oxygen saturation during the 48 hours after bidirectional cavopulmonary shunting, which ranged from 61.6% to 95.6%. There was a significant inverse correlation between the postoperative superior vena cava pressure and the arterial oxygen saturation (P =.003). A low arterial oxygen saturation early after bidirectional cavopulmonary shunting was a predictor of mortality or exclusion from univentricular repair within 24 months (P =.012, odds ratio = 1.14). Of 11 factors identified by univariable analysis, multiple regression analysis indicated that age less than 8 months at the time of shunting (P <.0001) and ventricular volume overload (P =. 002) predicted a lower arterial oxygen saturation after bidirectional cavopulmonary shunting. CONCLUSIONS: Even without additional sources of pulmonary blood flow, several preoperative factors, including younger age and severe ventricular volume overload, predicted a decrease in the arterial oxygen saturation early after bidirectional cavopulmonary shunting. This, in turn, predicted poor outcome during 2 years of follow-up.
We report herein the results of a retrospective study conducted on ten consecutive Japanese patients who underwent successful surgical relief of fixed subaortic stenosis between 1972 and 1994 at ages ranging from 8 months to 21 years, and followed for 3.6 years and 26 years. Associated cardiovascular defects were present in six patients, two had a history of infective endocarditis, a discrete fibrous ring was found in nine patients, and a redundant abnormal sheet was found in one. A stenotic structure was removed in nine patients and incised in one, while myotomy was additionally performed in one. There were no early complications or deaths. Cardiac catheterization revealed a significant decrease in the peak systolic pressure gradient from 84+/-22 mm Hg preoperatively to 32+/-22 mm Hg postoperatively (P = 0.0017). Reoperation of an aortic valve replacement with or without valvular annulus enlargement was required in four patients because of a small annulus with aortic insufficiency or infective endocarditis. Infective endocarditis was a major cause of late mortality (n = 1) and morbidity (n = 1), but the remaining eight patients have been asymptomatic. Thus, although this lesion is relatively rare in Japan, the typical discrete type may be more common than previously believed. While a relief operation is associated with low early mortality, the palliative aspect regarding pathology of the aortic valve should not be underestimated, including poor growth of the valve annulus, deterioration of aortic insufficiency, and infective endocarditis. The most appropriate operative procedure for reoperation remains to be evolved.
BACKGROUND: The bidirectional cavopulmonary shunt has been increasingly accepted as an interim step to the Fontan operation. However, the effect(s) of chronic volume overload on ventricular function are not yet well understood. METHODS: Twelve mongrel dogs, with (chronic volume overload group), or without (control group) a femoral arteriovenous shunt created 8 weeks before the assessment, were subjected to a right heart bypass from the right atrium to the proximal pulmonary trunk. Nonpulsatile perfusion via the bypass was achieved using a centrifugal pump and cross-clamping of the pulmonary trunk. Left ventricular function was evaluated using the end-systolic elastance and the Doppler flow pattern on echocardiograms (epicardiac and transesophageal, simultaneously) during acute volume loading. RESULTS: The left ventricular weight and the left ventricular weight/end-diastolic volume ratio showed no change from control values. The sum of the isovolumetric contraction time and the isovolumetric relaxation time divided by the ejection time remained constant during acute volume loading in the chronic volume overload group, while an increase was demonstrated in the control group. The chronic volume overload group showed a lower Ees (30.8 +/- 16.4 mmHg/cm2 vs. 107.6 +/- 70.3 mmHg/cm2, p = 0.03) than the control group. CONCLUSIONS: The global ventricular performance changed with chronic adaptation to the arteriovenous shunt, and became resistant to acute volume loading. Left ventricular contractility under nonpulsatile pulmonary perfusion was impaired by chronic volume overload, which is deleterious to the Fontan operation.
BACKGROUND AND OBJECTIVE: Holmium YAG (Ho:YAG) laser energy is highly absorbed by water, and this property is useful to uniformly ablate pulmonary bullae. The current study summarizes the data of a 39-month follow-up of patients treated for bullae with a Ho:YAG laser. STUDY DESIGN/MATERIALS AND METHODS: We used a Ho:YAG laser from August 1994 to April 1997 to treat small pulmonary bullae in 50 patients. For the first five patients, Ho:YAG laser ablation was followed by resection for histological assessment. In the next six patients, fibrin glue was applied following bullae ablation with the Ho:YAG laser. In all subsequent patients, a DEXON, (polyglycolic acid) mesh patch soaked in fibrin glue was employed after ablation. RESULTS: From the six patients receiving only the fibrin glue following laser ablation, delayed pneumothorax developed in one patient. In the subsequent 39 patients patched with DEXON mesh soaked in fibrin glue, none encountered delayed pneumothorax. CONCLUSION: The combined use of fibrin glue and Dexon mesh with the Ho:YAG laser may be an effective technique for treating bullous lung disease.
The purpose of this study is to assess the value of near-infrared spectroscopic oxymetry (NIRO) in monitoring cerebral oxygenation and metabolism during selective cerebral perfusion (SCP) for surgery of the aortic arch. The measurement protocol during SCP comprised oxyhemoglobin (HbO2), deoxyhemoglobin (Hb), and total hemoglobin levels in the brain. From March 1994 through March 1997, 14 patients underwent surgical treatment of the aortic arch anomalies with intraoperative monitoring with NIRO. The temporary circulatory arrest was accomplished at a rectal temperature of 22 degrees C and the hypothermic SCP was employed for the cerebral protection. SCP was initiated at a flow rate of 10 ml/kg/min so as to maintain HbO2 at the same level as immediately before the circulatory arrest (baseline). The longitudinal changes of HbO2 level during the process revealed four different patterns and were grouped accordingly. Three of the patients maintained HbO2 level above the baseline during SCP (Group A). HbO2 level reached to the baseline at initial flow rate but decreased gradually thereafter in 4 patients (Group B). Gradual increment of the perfusion flow rate failed to elevate HbO2 level to the baseline in the 5 patients (Group C1). In this group, HbO2 level started to elevate about 60 minutes after the initiation of SCP. HbO2 level of the remaining 2 patients was absolutely resistant to the increment of SCP flow rate and kept low values throughout SCP (Group C2). All the patients recovered uneventfully without any neurological abnormality. Our analyses for the longitudinal behavior of the HbO2 level confirmed the previously reported evidences that the values were affected not only by perfusion flow rate but also by hemodilution, blood transfusion, and perfusion pressure. Furthermore, our present study disclosed another evidence that HbO2 level was strongly affected by subclavian steal phenomenon. Although there were no differences in the clinical outcome among the groups, referring to the theories that HbO2 level is better not to be departed from baseline level, it could be concluded that HbO2 level monitoring in the setting of the determined hematocrit and hypothermia was effective for securing the adequate demand and supply balance of the cerebral oxygenation. Our conclusion may extend further that NIRO is a useful means in determining the optimal perfusion flow rate of SCP during surgery of the aortic arch.
There are no objection against that pulmonary vascular resistance index (PVRI) is one of the most important factors for completion of successful application of Fontan-type operation. However, calculated PVRI in single ventricle physiology in often unreliable because of difficulty in accurate measurement of pulmonary blood flow, especially in patients with decreased pulmonary blood flow. Although the role of bidirectional cavopulmonary shunt (BCPS) in such patients has been increasingly recognized, the impact of BCPS on PVRI has not been fully understood. Between November 1993 and November 1996, 24 patients, aged between 0.54 and 22.2 years, with a wide variety of cardiac malformations underwent BCPS, and were followed up for the mean of 15.1 months. There were four hospital deaths (16.7%) and three deaths in follow-up (12.5%). Serial catheterization revealed that significant increase in mean arterial oxygen saturation from 75.8% to 83.9% (p = 0.005), and decrease in mean Nakata's index from 433 to 311 (p < 0.0001). PVRI calculated by using formulas derived from Ohm's law before BCPS (Pulmonary flow was derived from Fick formula) was highly (greater than 10 u.m2) or moderately (between 4 and 10 u.m2) elevated in 6 and 7 patients, respectively. However, PVRI in these patients was normal after BCPS. Fourteen out of 24 patients underwent total cavopulmonary connection (TCPC) with 8 to 15 months of interval from BCPS, and have been currently surviving, and in NYHA functional class I or II, except 2 patients who underwent take-down. In conclusion, early and midterm outcome after staged operation appears to be excellent. BCPS is a good interim procedure, in part because one can more properly select patients undergoing Fontan operations from the PVRI point of view.
PURPOSE: We investigated whether verapamil (VR), a known chemosensitizing agent of P-glycoprotein-mediated multidrug resistance, could enhance the preventative effect of doxorubicin (Adriamycin, ADM) on both intravesical recurrence and disease progression after transurethral resection (TUR) of superficial bladder cancer. METHODS: The patients were randomized into two groups: one group received an intravesical instillation of ADM (30 mg) plus VR (15 mg) after TUR of superficial bladder cancer (19 times over 1 year), and the other group received ADM alone on the same treatment schedule. The nonrecurrence rate, the incidence of disease progression at the first recurrence and the side effects were compared over a median follow-up of 38.5 months. RESULTS: Of the 226 patients registered, 157 were evaluable. No significant differences were observed in the patients' characteristics between the two groups. Although the incidence of disease progression at the first recurrence was not significantly different between the two groups, the ADM plus VR instillation group did show a significantly higher nonrecurrence rate than the ADM-only instillation group, and such significance persisted even when any possible bias was allowed for in a multivariate analysis. In terms of side effects, the incidence and severity of bladder irritation symptoms were not significantly different between the two groups. CONCLUSIONS: Intravesical instillation chemotherapy with ADM plus VR was found to have a significantly greater beneficial effect than with ADM alone for preventing recurrence after TUR of superficial bladder cancer.
Pamlin, an important extracellular protein required early for sea urchin embryogenesis, is readily isolated from the embryos of Hemicentrotus pulcherrimus. A molecular image analysis of pamlin was conducted using immuno-electron microscopy, rotary shadowing and negative staining technique-applied electron microscopy. The electron microscopy showed that a monoclonal antibody to the pamlin alpha-subunit bound to a position 13.5 nm from one end of a purified 255 kDa pamlin molecule, which is a 132 nm long and 6.8 nm wide linear structure. The pamlin structure is composed of three subunits, a 47 nm long 52 kDa alpha-subunit that attaches to one end of a 105 nm long 180 kDa beta-subunit, and a 15.6 nm diameter globular 23 kDa gamma-subunit that binds to the middle of the beta-subunit. The alpha- and beta-subunits together form a 125-140nm linear structure. Intermolecular aggregation frequently occurred between the free end of two beta-subunits of the alphabetagamma pamlin molecule, leaving the entire alpha-subunit surface free. Occasionally associations between the ends of alpha-subunits, or between an alpha-subunit and the middle of a beta-subunit also occurred, but no aggregations of pamlin formed through the gamma-subunit. These homophilic molecular aggregations of pamlin formed a large supramolecular network. In addition, the single pamlin molecule rounded at one end under high calcium ion concentration to form a 'loop', suggesting the presence of a calcium sensitive region in the molecule.
PURPOSE: To describe the clinical features of stromal keratitis in a patient with cytomegalovirus (CMV) retinitis and acquired immunodeficiency syndrome (AIDS). METHODS: Case report. RESULTS: Human CMV genome was detected in plasma, urine, and aqueous humor by polymerase chain reaction. CMV retinitis subsided and the corneal infiltrate was scarred within 4 weeks of systemic ganciclovir treatment. CONCLUSION: This is the first report of the corneal infiltration seen in an AIDS patient with CMV retinitis. Etiological significance of the finding is discussed.
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BACKGROUND: Radical nephrectomy is the standard therapy for low-stage renal cell carcinoma. However, recurrence sometimes develops even in patients who are considered to have undergone a curative resection of the primary tumor. The purpose of this study was to evaluate the usefulness of UFT (a 1:4 mixture of tegafur and uracil) adjuvant and the risk factors for recurrence in renal cell carcinoma. METHODS: A prospective randomized trial was conducted to compare the use of long-term oral UFT adjuvant with nonadjuvant therapy after a radical nephrectomy for Robson stage I or II renal cell carcinoma. A multivariate analysis was also performed to estimate the risk factors for recurrence. RESULTS: A total of 71 patients were entered into this study, and 66 were evaluable (33 for each group). There was no significant difference in patient characteristics between the 2 groups. The nonrecurrence rate at 5 years after a radical nephrectomy was 80.5% and 77.1% in the UFT adjuvant group and the nonadjuvant group, respectively, with a median follow-up of 112.9 months; the difference was not significant. The toxicity of UFT was generally mild and tolerable. The tumor grade was found to be an important factor influencing recurrence. CONCLUSION: UFT cannot be universally recommended as an adjuvant therapy for radical nephrectomy in all patients with low-stage renal cell carcinoma.
BACKGROUND: The postoperative intravesical instillation of doxorubicin (ADM) has a preventative effect on recurrence after a transurethral resection (TUR) of superficial bladder cancer. However, the significance of preoperative ADM instillation remains unclear. Although the oral administration of 5-fluorouracil (5-FU) has been observed to show some clinical response against bladder cancer, its preventative effect on the recurrence of superficial bladder cancer after TUR is unknown. METHODS: Patients were randomized into 4 groups. All 4 groups received postoperative ADM instillation. In addition, patients in groups C and D received preoperative ADM instillation, whereas patients in groups B and D additionally received oral 5-FU postoperatively. The nonrecurrence rate and side effects were both compared among the 4 groups. RESULTS: Of the 282 patients registered, 200 were evaluable, with a median follow-up period of 21.4 months. There were no significant differences in the characteristics of the patients among the 4 groups. Group C (pre- and postoperative ADM) showed a significantly longer disease-free interval than group A (postoperative ADM alone). However, there was no significant difference in the disease-free interval between groups A and B (postoperative ADM plus 5-FU), or between groups C and D (pre- and postoperative ADM plus 5-FU). Bladder irritation symptoms were the most frequently noted side effect encountered in all groups, but the severity was generally mild. CONCLUSIONS: Preoperative ADM instillation was found to prevent recurrence to a greater extent than the usual postoperative instillation alone, whereas oral 5-FU was found to have no additional beneficial effect on the disease-free interval in patients with superficial bladder cancer.