[Evaluation and problem points in reconstruction of the mitral valve based on follow-up results].
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Chordae Tendineae↗
Biomedical subjects
Y Kito
Publications and source records attributed to Y Kito.
[Clinical study of re-do surgery after Bentall-type operation].
Among patients who underwent reconstruction of the aortic root by Bentall-type procedure using a composite graft, we investigated patients who underwent reoperation for complications related to composite graft. We employed composite graft reconstruction of the aortic root in 155 patients for 16 years prior to December 1994. Annulo-aortic ectasia was observed in 112 patients, aortic dissection in 34, and aortitis without aneurysm formation in 9. The original Bentall procedure was performed in 36, the Cabrol method in 8, the interposition method in 26, and the Carrel patch method in 85 patients. Thirteen (8.4%) of these patients required reoperation for complications related to the composite graft. Three of 4 patients with graft infection early after surgery underwent reconstruction with composite graft, but died in the hospital. The remaining patient survived after combined treatment that included the graft washing with Iodine (Isozin) solution and omentopexy. Four patients developed pseudoaneurysm formation due to sutural insufficiency and 7 has prosthetic valve failure as late complications. Three of the 4 patients with pseudoaneurysm underwent reconstruction with a second composite graft by the interposition method, while one patient with aortitis required another reoperation. In the remaining one patient, the leak was directly close along with second aortic valve replacement. All prosthetic valves used in 7 patients with prosthetic valve failure were Ionescu-Shiley biological valves. Primary tissue failure was observed in 6 and prosthetic valve endocarditis in one patient. Second cardiac valve replacement using a mechanical valve was possible. All the patients who underwent late reoperation showed favorable results. Infection of the composite graft showed the poor prognosis, and prevention of infection is important. Sutural insufficiency at the anastomosed site can be prevented by appropriate surgical procedures such as reinforcing suture, but further countermeasures for sutural insufficiency were considered necessary for aortitis in conditions, such as Behcet's diseases.
Adult↗
Squid photoreceptor phospholipase C is stimulated by membrane Gq alpha but not by soluble Gq alpha.
Phospholipase C (PLC) was purified from squid retina. Soluble Gq alpha, membrane Gq alpha and G beta gamma were isolated from GTP gamma S-treated and light-illuminated photoreceptor membranes. The membrane Gq alpha stimulated phosphatidyl inositol-phospholipase C (PI-PLC) activity in a dose-dependent manner. Soluble Gq alpha and membrane G beta gamma showed no stimulating effects on PLC. GTP gamma S-binding was found exclusively in membrane fraction, with very little present in the KCl-soluble fraction which contained soluble Gq alpha. These results indicate that light-activated rhodopsin activates PLC through membrane-bound Gq alpha and suggest that the rhodopsin/Gq/PLC cascade might be the pathway of phototransduction in squid photoreceptors.
Animals↗
Modified maze procedure for patients with atrial fibrillation undergoing simultaneous open heart surgery.
BACKGROUND: Persistent atrial fibrillation (AF) leaves patients symptomatic and at increased risk of thromboembolism even after otherwise successful cardiac surgery. METHODS AND RESULTS: To treat AF secondary to cardiac lesions requiring surgery, we combined a modified maze procedure in 101 patients simultaneously undergoing valvular procedures (87), repair of congenital anomalies (12), and other procedures (2), including 24 repeat operations. Duration of AF varied from 0.1 to 30 years (average +/- SD, 8.8 +/- 7.0 years); the f-wave voltage ranged from 0 to 0.45 mV (0.15 +/- 0.09 mV); and cardiothoracic ratio varied from 40% to 99% (63 +/- 9%). Aortic cross-clamp time varied from 75 to 229 minutes (138 +/- 31 minutes), with bypass time ranging from 119 to 326 minutes (217 +/- 42 minutes). There were two early deaths (2%), no late deaths, and one episode of transient neurological ischemic attack in follow-up ranging from 1.0 to 3.1 years, for a total of 190 patient-years. Postoperative rhythms were sinus in 83 patients (82%), junctional in 4 (4%), and persistent AF in 14 (14%), each of whom had mitral valve disease. Patients with other underlying pathology had complete recovery of atrial rhythm. A normal-sized A wave was detected in 88% for transtricuspid flow and in 73% for transmitral flow, suggesting concomitant recovery of atrial contraction. Among 36 patients without mechanical valves, 30 (83%) with atrial rhythm and contraction have been taken off anticoagulation therapy, including 10 who are free of all medication. CONCLUSIONS: The results suggest that the combined approach is safe, effective, and indicated in patients who are judged capable of tolerating the procedure and likely to regain atrial rhythm.
Aged↗
Phosphatidyl inositol-phospholipase C in squid photoreceptor membrane is activated by stable metarhodopsin via GTP-binding protein, Gq.
Phosphatidyl inositol-phospholipase C (PI-PLC) in squid retina was studied by immunoblotting and its activities were determined using [3H]phosphatidyl inositol bisphosphate ([3H]PIP2) as substrate. PI-PLC activity was found mostly in soluble fraction when the retina homogenate was treated with 400 mM KCl, but was associated with rhabdomal membranes under low salt conditions (20 mM Hepes). A protein with apparent molecular mass of 130kD was recognized by an antibody against PLC beta 4/norp A in both 400 mM KCl soluble and rhabdomal membrane fractions. A 42 kD protein recognized by antibody against the C-terminus of Gq alpha was also present in these two fractions. GTP gamma S stimulated only the PI-PLC activity associated with membrane and was magnesium dependent. PI-PLC activity was found to be (i) highly dependent upon calcium concentrations, (ii) enhanced by GTP but not by other nucleotides, and (iii) significantly stimulated by light at lower concentrations of GTP gamma S. The stimulation by light was still observed when irradiated membrane was incubated at 10 degrees C for 10 min and then mixed with GTP gamma S. These results suggest that stable metarhodopsin stimulates a PLC beta 4/norp A-like enzyme via a G-protein, Gq.
Animals↗
The nitrate reductase gene from a shoyu koji mold, Aspergillus oryzae KBN616.
A niaD gene encoding nitrate reductase was isolated from Aspergillus oryzae KBN616 and sequenced. The structural gene comprises 2973 bp and 868 amino acids, which showed a high degree of similarity to nitrate reductases from other filamentous fungi. The coding sequence is interrupted by six introns varying in size from 48 to 98 bp. The intron positions are all conserved among the niaD genes from A. oryzae, Aspergillus nidulans, and Aspergillus niger. A homologous transformation system was developed for an industrial shoyu koji mold, A. oryzae KBN616, based on the nitrate reductase (niaD) of the nitrate assimilation pathway.
Amino Acid Sequence↗
[The effects of Ebselen upon post-ischemic functional recovery in rat heart].
The effects of Ebselen (DR-3305) upon cardiac function and CK leakage with or without ischemia reperfusion insults were investigated in this isolated working rat heart study. In order to evaluate the effects of Ebselen upon cardiac function, it was administrated to the isolated rat heart with Langendorff perfusion for 15 min at 100 cmH2O. Cardiac functions such as aortic and coronary flow, heart rate and aortic pressure, before and after Ebselen treatment, were measured and expressed as percent of the control value. The coronary resistance was significantly reduced in 100 nM, 500 nM and 1000 nM of Ebselen pretreatment with dose dependent manner. However pretreatment with 1000 nM of Ebselen significantly decreased cardiac output with significant increase of CK leakage. The myocardial protective effects of Ebselen in the cardioplegia or reperfusate were investigated under conditions of normothermic ischemia. After measuring preischemic cardiac functions, the St. Thomas' Hospital cardioplegic solution was infused for 3 min followed by 35 min of global ischemia at 37 degrees C. Hearts were then aerobically reperfused for 15 min in the Langendorff mode. Subsequently, cardiac function was measured and expressed as percent of the preischemic control value. Ebselen addition to the St. Thomas' cardioplegic solution did not possess any myocardial protective effects, although addition to reperfusate possess the protective abilities at a concentration of 10 nM. From these data, Ebselen, which was one of the free radical scavenger, had the myocardial protective effects if it was added to reperfusate at a concentration of 10 nM.
Animals↗
[Surgical treatment and long-term results of cardiac myxoma in 38 patients].
Long-term results of thirty-eight patients with cardiac myxoma, who underwent resection at National Cardiovascular Center between May, 1978 and December, 1993, were reviewed focussing on embolism, cerebral complication, tumor recurrence and metastasis. The mean age was 49.6 years (range 0 to 74) in 20 female and 18 male. Overall follow-up were known for 35 of 38 patients (92.1%), and an average of follow-up period was 6.7 years (range 0.5 to 15.9 years). 15 of 38 patients (34.2%) had embolism (brain 10, peripheral artery 4, coronary 1) preoperatively. All patients survived operation and the hospital mortality rate was 0%. Long-term results were almost satisfactory (myxoma related-death in one patients). However, distant metastasis occurred in two patients, and tumor recurrence in one patient irrespective of a presence of preoperative embolism. Cerebral embolism occurred in one patient and cerebral arterial lesins were noticed in five patients postoperatively. Cardiac myxoma has a malignant potentiality and a close follow-up is necessary about recurrence, metastasis and cerebral artery disease.
Adolescent↗
[Results of coronary artery bypass grafting in dialysis patients].
To determine the short- and medium-term results of coronary artery bypass grafting (CABG) in dialysis patients, we analyzed a group of 14 patients with chronic renal failure who underwent CABG between May 1990 and October 1994. Two patients had concomitant valve repair for mitral regurgitation. Hospital mortality was 14% (2 out of 14). These two patients died of ileus due to ischemic colitis and agranulocytosis respectively. There was one late death from stroke. The four significant postoperative complications (morbidity 29%) were composed of two sternal dehiscence, one cardiac tamponade because of bleeding, and one perioperative myocardial infarction. Graft patency rate was 97% (34 out of 35 in 13 patients) within one month. Actuarial survival was 86% at one 1 to 3 years, and 43% at 3 and a half years. This rate is not significantly different from all dialysis patients, but night be better than dialysis patients with coronary artery disease who had not undergone CABG in the previous reports. Left ventricular size is larger in patients who died or who had significant complications in hospital than in patients with uneventful postoperative course. Cardiac arrest time, cardiopulmonary bypass time, chest tube output, and the amount of transfusion might be also related to mortality and morbidity though statistically not significant.
Aged↗
[Evaluation of surgical procedures based on the types of hypertrophied obstructive cardiomyopathy].
The surgical procedures were reviewed based on the types of hypertrophied obstructive cardiomyopathy in 20 patients. The patients were classified in three groups: (1) Asymmetric septal hypertrophy (ASH), (2) Atypical or diffuse concentric hypertrophy (DIF), (3) Mid ventricular obstructive hypertrophy (MID). Among 11 patients with ASH, the ventricular septal myotomy (My) or the myotomy-myectomy (Mye) were performed in 9 patients and MVR was performed in 2 patients. Among 6 patients with DIF, My or Mye were performed in 4 and MVR was performed in 2. All three patients with MID were treated with MVR. The intraventricular systolic pressure gradient greater than 40 mmHg was still existent postoperatively in one ASH patient on whom Mye was performed and in 3 DIF patients on whom My or Mye were performed. The four patients had III degree mitral regurgitation preoperatively and were successfully treated. The postoperative NYHA functional class became II or less in all patients. For ASH, the My was effective in 9 patients except one earlier patient. For DIF, further consideration of surgical procedure might be required. For MID, a MVR is recommended.
Adult↗
The specific binding site of the volatile anesthetic diiodomethane to purple membrane by X-ray diffraction.
To determine the binding site of volatile anesthetics on purple membrane, diiodomethane (CH2I2) was used as a label in X-ray diffraction experiments. At less than 3 mM diiodomethane, purple membrane retains its two-dimensional crystallinity of bacteriorhodopsin, absorption spectra show only a little blue shift and the decay time of the M-intermediate becomes fast in flash photolysis experiments. These effects are similar to those of other anesthetics previously studied. The position where the anesthetic binds was identified by difference Fourier methods, and refined by model calculations. This study suggests that volatile anesthetics bind specifically to the protein-lipid interfacial region near the surface of membrane.
Anesthetics↗
X-ray diffraction study of the live squid retina.
In previous studies of invertebrate rhabdomes by X-ray diffraction, glutaraldehyde fixation of the retina was used because this tissue is very labile and, without fixation, disintegrates within an hour of dissection. However, with conventional X-ray apparatus more than ten hours exposure time was needed to record a diffraction pattern. In this study, X-ray diffraction patterns from unfixed squid retina could be successfully obtained by use of synchrotron radiation and a storage phosphor screen as detector. The diffraction spots were indexed on a two-dimensional hexagonal lattice of 60 nm. X-ray data was analysed by comparing Patterson functions calculated from the diffraction intensities with those based on model building. The hexagonal shape of microvillar cross section was suggested by the systematic weakness of (0, k) reflections beyond k = 4 and the appearance of the six symmetry-related diffuse maxima around (4 nm)-1. The best-fitting model showed a large gap between adjacent microvilli (approximately 12 nm), which has been expected (for ionic current flow through the inter-microvillus space to generate the membrane potential) but not observed with the chemically fixed retina, possibly due to an artifact of fixation. Also, the existence of massive inter-microvillus material, scarcely observed by conventional electron microscopy, has been confirmed.
Animals↗
Prediction of postoperative exercise tolerance after aortic valve replacement.
Valve size selection for aortic valve replacement is still a controversial matter, particularly in patients with small aortic annuli. To assess optimal valve size, exercise capacity, as measured by peak oxygen consumption levels, was determined in 39 patients (age range, 18 to 77 years; mean, 56 years) who underwent isolated aortic valve replacement with a St. Jude Medical valve. This assessment was carried out at a mean of 2.2 years post-operatively using ergometer exercise testing. These levels were evaluated as a measure of the percentage of predicted. At rest, there was no significant correlation between the predicted peak oxygen consumption and the pressure gradients across the prostheses, as measured by Doppler ultrasound. In 18 patients with aortic regurgitation, the preoperative dimensions of the left ventricle in end-diastole and end-systole correlated inversely (p < 0.05) with the percentage of predicted peak oxygen consumption. In 21 patients with aortic stenosis, the linear regression line (p < 0.01) was derived from the correlation between the percentage of predicted peak oxygen consumption and the valve area index (geometric valve orifice area/body surface area). We conclude that the preoperative end-systolic and end-diastolic dimensions should be less than 50 mm and 70 mm, respectively, in the setting of aortic regurgitation, and a valve area index, though it proved to be weakly correlated with the percentage of the peak oxygen uptake, should probably be more than 1.5 cm2/m2 in the setting of aortic stenosis to achieve good exercise capacity postoperatively (> 80% of predicted peak oxygen consumption).
Adolescent↗
Purification and characterization of triokinase from porcine kidney.
In order to be able to use triokinase for the enzymatic assay of tissue glyceraldehyde, we purified the enzyme to homogeneity from porcine kidney and characterized its biochemical properties. The purification was performed by polyethylene glycol fractionation, anion exchange chromatography, hydroxyapatite chromatography, hydrophobic chromatography, and gel filtration. The enzyme was purified 937-fold from the crude extract with an overall yield of 28%. It had a molecular weight of 122,000 and was a dimer composed of identical subunits. The optimal pH and optimal temperature were 7.0 and 60 degrees C, respectively. This enzyme was stable when incubated at pH 7.0 at 40 degrees C for 1 h in the presence of 0.1 mg/ml bovine serum albumin. No loss of activity occurred for at least 1 month when the enzyme was stored at 4 degrees C in the presence of 1 mM dithiothreitol and 15 mM NaN3 under N2. Only three compounds, i.e., D-glyceraldehyde, dihydroxyacetone, and glycolaldehyde, acted as the substrate of the enzyme, having Km's of 11, < 5, and 260 microM, respectively. The Km for ATP-Mg2+ was 68 microM. These results indicate that porcine kidney triokinase has properties advantageous for the glyceraldehyde assay using glyceraldehyde-3-phosphate dehydrogenase as a coupling enzyme.
Amino Acid Sequence↗
STRUCTURAL BASIS FOR WAVELENGTH DISCRIMINATION IN THE BANKED RETINA OF THE FIREFLY SQUID WATASENIA SCINTILLANS
There is a greatly thickened region of retina in the ventral part of the eye of the firefly squid Watasenia scintillans, with an outer segment (OS) layer around 600 µm thick. The distal two-thirds of this OS layer is yellow and contains a visual pigment, based on 4-hydroxyretinal (A4), with an absorbance maximum at 470 nm. The proximal third is pink and contains a visual pigment, based on dehydroretinal (A2), with an absorbance maximum at 500 nm. Light and electron microscopic investigations demonstrate the presence of four types of photoreceptor cell. In the pink layer, three of the four types (alpha, ß and gamma) produce no microvilli and are columnar in structure. These cells form square microvillous rhabdoms only in the distal yellow layer. The fourth cell type (delta) produces microvilli in the pink layer only. These observations led us to propose that the A2-based visual pigment is contained in the pink-layer cells and that the A4-based visual pigment is contained in the three types of yellow-layer cells. The absorbance of fresh retina was determined by microspectrophotometry. The yellow OS layer, with an absorbance of 0.7 per 100 µm thickness at 470 nm, is expected to act as a short-wavelength cut-off filter to the underlying pink OS cells, shifting their photosensitivity peak by an estimated 50 nm to 550 nm. Possible wavelength discrimination by this squid is discussed.
Journal Article↗
[Grafts materials and the choice for technique].
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Coronary Artery Bypass↗
[A case of aortitis operated twice Bentall's operation due to valve (graft) detachment].
A 40-year-old man had received emergency Bentall's operation due to acute aortic regurgitation (AR) of aortitis in October, 24, 1990. On out patient clinic, the CRP had been kept from 0.5 to 1.5 mg/dl in dose of 10 mg of prednisolone. In the midnight of November, 17, 1992, his condition deteriorated to circulatory shock and echocardiography revealed massive AR due to para-annular graft detachment with large pseudoaneurysm of 50 mm. He was transferred for emergency operation. The composite graft shifted 2-3 cm above the annulus and detached in three quarter of the annulus. Distal anastomosis was also detached in half of anastomosis and coronary anastomosis almost detached. He was operated on modified Bentall's operation employing Piehler's technique and he is now followed in dose of 10 mg of prednisolone. There are some cases of aortitis showing recurrent valve or graft detachment like this case, even if modified Bentall's operation have been done to decrease the mechanical stress to the annulus and the inflammation have been controlled under the dosage of steroid.
Adult↗
[Myocardial preservation by continuous perfusion of Krebs-Henseleit solution--the temperature dependency of the optimal perfusion pressure].
The aim of this study was to determine the temperature dependency of the optimal pressure in myocardial preservation by continuous perfusion with Krebs-Henseleit bicarbonate buffer (KHBB) solution. Hearts from Wistar male rats were perfused with KHBB solution and cardiac function (aortic flow) was measured using an isolated working rat heart preparation. In the preliminary experiment, hearts were then preserved using Langendorff perfusion with KHBB solution of 37, 20 or 4 degrees C for 2 hours at a perfusion pressure of 100 cmH2O. This was followed by 15 min of Langendorff perfusion (37 degrees C, 100 cmH2O) and 20 min working perfusion. The 37 degrees C group and 20 degrees C group exhibited better functional recoveries of aortic flow (%AF) in the post-preservation period compared to the 4 degrees C group. In the test experiment, hearts were preserved using Langendorff perfusion for 4 hours at 37 degrees C or for 8 hours at 20 degrees C at various perfusion pressures. At 37 degrees C, %AF after 4 hours of the preservation were 64.7 +/- 2.6, 69.0 +/- 3.2, 81.9 +/- 3.1, 94.7 +/- 3.3 and 63.5 +/- 4.0% (p < 0.05 vs the 100 cmH2O group) at the perfusion pressure of 100, 60, 20, 15 and 10 cmH2O, respectively. %AF after 8 hours of the preservation at 15 cmH2O was 56.3 +/- 2.5%. At 20 degrees C, %AF after 8 hours of the preservatin was 78.9 +/- 3.3, 81.9 +/- 2.3, 67.4 +/- 1.9 and 65.9 +/- 2.2% (p < 0.05 vs the 60 cmH2O group) at the perfusion pressure of 60, 30, 10 and 15 cmH2O, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)
Animals↗