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Biomedical subjects

T Tabata

Publications and source records attributed to T Tabata.

At least 37 records · Page 2Linked to original sources
PubMed1995

Response characteristics of periodontal mechanoreceptors to mechanical stimulation of canine and incisor teeth in the cat.

The alveolar bone that overlies the labial aspect of the root of the right lower canine tooth was pared down until paper thin. Thirty-five periodontal mechanosensitive (PM) units sensitive to stimulation of the canine and incisor and to punctate stimulation through the thinned bone of the periodontal ligament of the canine were recorded from the inferior alveolar nerve rostral to the masseter muscle. The units showed a sustained and directionally selective response to pressure applied to the teeth. The optimal directions of stimulation for each tooth in the receptive field were parallel and oriented linguolabially. When the canine was stimulated mechanically in the optimal stimulus direction, the interspike intervals of the responses were relatively regular in most PM units (91%). The conditioning and test stimuli were applied to the adjacent canine and third incisor. The conditioning stimulus (0.10 N) was given to one of these teeth in the optimal stimulus direction. The test stimulus (0.02 N or 0.05 N) was applied to the adjacent tooth in the opposite direction in order to examine the effect of mechanical spreading of the conditioning stimulus on the adjacent tooth. In most PM units, the spike discharges evoked by the conditioning stimulus given to the incisor were stopped by the test stimulus given to the canine. When the given stimuli were reversed, the firings evoked by the conditioning stimulus were slightly depressed by the test stimulus. After removing the spot-like PM receptor site(s) in the paper-thin area of bone, all units but one did not respond to stimulation. These results provide evidence that neurones with multiple-tooth receptive fields and regular spike-interval responses recorded from the inferior alveolar nerve come from the mechanical spreading effect of the stimulation of one tooth on an adjacent tooth through the trans-septal fibre system and that neurones with irregular-interval responses are due to the ramification of PM fibres peripherally.

Alveolar Process↗
PubMed1995

Selection and characterization of sequences with high affinity for the engrailed protein of Drosophila.

The engrailed gene helps to direct Drosophila melanogaster development by encoding a homeodomain-containing DNA binding protein. To identify genes whose transcription engrailed regulates, we developed a method to isolate genomic sequences to which engrailed protein binds with high affinity. Fragments of genomic DNA were fractionated on an engrailed protein affinity column, and fragments that were retained in the presence of 0.4-1.0 M KCl were isolated and cloned. The isolated fragments include regions of the engrailed and cubitus interruptus gene promoters, both of which are candidate targets of engrailed, and most fragments contain regions that engrailed protein protects from DNaseI digestion. Chromosomal deletions that remove some of the engrailed binding sites (located either at 64D, 96B or 99D) interact genetically with engrailed. Characterization of a transcript encoded in region 64D revealed its dependence on engrailed protein.

Amino Acid Sequence↗
PubMed1995

High-resolution B-mode ultrasonography in evaluation of atherosclerosis in uremia.

We sought to determine whether artherosclerosis may be accelerated in uremic patients on maintenance hemodialysis and investigated the risk factors for carotid and femoral atherosclerosis in such patients. High-resolution B-mode ultrasonography was used to determine the intima-media thickness (IMT) of the carotid and femoral arteries in 199 hemodialysis patients and 81 age-matched healthy controls subjects. The IMT values of the carotid and femoral arteries in the hemodialysis patients were significantly higher than in age-matched control subjects in most age groups. The IMT values of the carotid or femoral artery were significantly correlated with age in both the hemodialysis patients and the control subjects. There was a significant relationship between the IMT values of the two arteries in the hemodialysis patients (r = 0.418, P = 0.0001) and in the control subjects (r = 0.321, P = 0.0037). Multiple regression analysis showed that age, cigarette smoking, and uremic state were independent risk factors for atherosclerosis of both arteries in the patients and the control subjects (R2 = 0.174, P < 0.0001; R2 = 0.205, P < 0.0001, respectively). In the hemodialysis patients, the independent risk factors associated with the extent of the IMT of the carotid artery were age, cigarette smoking, and serum phosphorus level (R2 = 0.230, P < 0.0001), while those associated with the extent of the IMT of the femoral artery were age, cigarette-smoking, and serum m-PTH level (R2 = 0.230, P < 0.0001).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

Burn injury induces a biphasic immunoglobulin M response to bacterial antigen.

We studied 75 BALB/c mice to examine the role of impaired immunoglobulin M (IgM) synthesis in the increased risk of bacterial infection after burn injury by investigating the kinetics of IgM synthesis to peptidoglycan polysaccharide (PGPS), a ubiquitous bacterial antigen. Splenocytes were isolated 1, 5, and 8 days postburn (PBD) and cultured with lipopolysaccharide for 5 days. Culture supernatant was collected and anti-PGPS IgM and total IgM levels were measured by ELISA. Total IgM-secreting cells were measured by ELISPOT assay. Total IgM and anti-PGPS IgM per IgM-secreting cell were calculated. On PBD 1, anti-PGPS IgM synthesis but not total IgM synthesis is increased in burned animals. By PBD 5, total IgM and anti-PGPS IgM synthesis in the burn group start to fall and by PBD 8, both are significantly decreased. The early increase in anti-PGPS IgM synthesis represents a positive response to bacterial challenge. However, the late nonspecific decrease in total IgM and anti-PGPS IgM synthesis suggests a potential mechanism for increased susceptibility to bacterial infection 5 to 10 days after burn injury.

Animals↗
PubMed1995

Creating a Drosophila wing de novo, the role of engrailed, and the compartment border hypothesis.

Anterior/posterior compartment borders bisect every Drosophila imaginal disc, and the engrailed gene is essential for their function. We analyzed the role of the engrailed and invected genes in wing discs by eliminating or increasing their activity. Removing engrailed/invected from posterior wing cells created two new compartments: an anterior compartment consisting of mutant cells and a posterior compartment that grew from neighboring cells. In some cases, these compartments formed a complete new wing. Increasing engrailed activity also affected patterning. These findings demonstrate that engrailed both directs the posterior compartment pathway and creates the compartment border. These findings also establish the compartment border as the pre-eminent organizational feature of disc growth and patterning.

Animals↗
PubMed1995

Evaluation of left ventricular diastolic hemodynamics from the left ventricular inflow and pulmonary venous flow velocities in hypertrophic cardiomyopathy.

We evaluated the characteristics of left ventricular diastolic hemodynamics in hypertrophic cardiomyopathy (HCM) by measuring left ventricular inflow (LVIF) and pulmonary venous flow (PVF) velocities in 62 patients with asymmetric septal hypertrophy and 34 normal controls. The patients were divided into four groups according to the LVIF pattern and left ventricular end-diastolic pressure (LVEDP): 1) the pseudonormalization group; 13 patients with the ratio of peak atrial systolic (A) to early diastolic (E) LVIF velocity (A/E) < or = 1 and LVEDP > or = 15 mm Hg, 2) the normal pattern group; 10 patients with the A/E < or = 1 and LVEDP < 15 mm Hg, 3) the relaxation failure group; 25 patients with the A/E > 1, and 4) the mid-diastolic wave group; 14 patients with a mid-diastolic wave. The peak early diastolic LVIF velocities in the pseudonormalization, relaxation failure and mid-diastolic wave groups were significantly smaller than in the control group. The deceleration time from the peak of the E wave and the isovolumic relaxation time were significantly prolonged in the relaxation failure and mid-diastolic wave groups. The peak diastolic PVF velocity in the relaxation failure and mid-diastolic wave groups was significantly decreased, and was significantly increased in the pseudonormalization group. The peak atrial systolic PVF velocity was significantly increased in all patients with HCM, particularly in the pseudonormalization group. LVEDP was the highest in the pseudonormalization group, followed by the mid-diastolic wave, relaxation failure and normal pattern groups, in that order. In conclusion, combined analysis of the LVIF and PVF provides useful information regarding various abnormalities of left ventricular diastolic hemodynamics in patients with HCM.

Adult↗
PubMed1995

The first heart sound in atrial septal defect with reference to atrioventricular valve motion and hemodynamics.

To clarify the characteristics of the first heart sound in atrial septal defect (ASD) and its pathophysiological basis, 17 patients with ASD associated with incomplete right bundle branch block (IRBBB) and 7 with isolated IRBBB were studied using phonoechocardiography and Doppler echocardiography. Fifteen of the 17 ASD patients also were studied following surgical closure of the defect. Indices were compared among the preoperative ASD, postoperative ASD, and IRBBB groups including: P-Q intervals, loudness of the mitral and tricuspid component of the first heart sound (IM, IT), end-diastolic closing excursions of the mitral and tricuspid valves (Mx, Tx), and mitral and tricuspid inflow velocities during early diastole and atrial contraction. There were no significant differences in the P-Q intervals among these 3 groups. IM was attenuated, and IT was accentuated in ASD compared with IRBBB. Postoperatively, IM was augmented in all but 1 patient and IT was attenuated in all patients. Mx was significantly smaller, and Tx was significantly larger in ASD than in IRBBB. Postoperatively, Mx was significantly increased and Tx was significantly reduced; the maximal mitral inflow velocity during atrial contraction was increased while the maximal tricuspid inflow velocity was significantly reduced. Thus, the first heart sound in ASD is characterized by an attenuated mitral component and an accentuated tricuspid component. Hemodynamic alterations and consequent changes in closing energies of the atrioventricular valves probably account for these features.

Adolescent↗
PubMed1995

[Effects of prostaglandin E1 (PGE1) on pulmonary hypertension and lung vascular remodeling in a rat monocrotaline model of human pulmonary hypertension].

Prostaglandin E1 (PGE1) has been shown to be a potent pulmonary vasodilator in humans and in many animals. The effects of PGE1 on the development of pulmonary hypertension and on pulmonary vascular remodeling were studied in a rat monocrotaline (MCT) model of human pulmonary hypertension. By 3 weeks after injection, MCT (80 mg/kg S.C.) had resulted in high values of mean pulmonary arterial pressure and of the ratio of right ventricular weight to left ventricle+septum weight (RV/LV+S). PGE1 inhibited the development of pulmonary hypertension (300 micrograms/kg) and right ventricular hypertrophy (300 and 100 micrograms/kg) induced by MCT. Three weeks after the injection, the media walls of pulmonary arteries in lungs from rats given MCT were significantly thicker than those from lungs of control rats. PGE1 (300, 100, and 30 micrograms/kg) resulted in significantly less of this morphologic change, in a dose-dependent manner. These results indicate that PGE1 inhibits the development of pulmonary hypertension associated with lung vascular thickening induced by MCT. PGE1 may be useful for the treatment of pulmonary hypertension in humans.

Alprostadil↗
PubMed1995

[Effect of adhesiveness of white blood cells on pulmonary vascular permeability and resistance].

We studied pulmonary vascular injury evoked by mechanically activated white blood cells (WBCs). In isolated perfused rat lungs, changes in pulmonary vascular resistance were measured, and a gravimetric method was used to measure the pulmonary vascular filtration coefficient, which was taken as an index of pulmonary vascular injury. WBCs were activated by gentle agitation in a glass container for 10 sec. The filtration coefficient was measured under baseline conditions, and then inactive or activated WBCs were added to the perfusate. The perfusion was stopped for 90 minutes and then the lungs were reperfused. The expression of CD18 on the surface of WBCs was measured by flow cytometry. The filtration coefficient and the pulmonary vascular resistance in lungs exposed to activated WBCs were about 2.5 times and 3.3 times higher, respectively, than those in the lungs exposed to inactive WBCs. These results indicate increases in resistance and in pulmonary vascular permeability. The results of flow cytometry indicated that the mechanical agitation increased the expression of CD18 on the surface of WBCs. In conclusion, WBCs in which adhesiveness has been increased can induce pulmonary vascular injury and can increase pulmonary vascular resistance.

Animals↗
PubMed1995

[Transesophageal echocardiographic study on the mechanisms of mitral regurgitation in hypertrophic cardiomyopathy: comparison with sigmoid septum].

Transesophageal echocardiography was performed to elucidate the mechanisms of mitral regurgitation (MR) in 40 patients with hypertrophic cardiomyopathy with asymmetric septal hypertrophy, 15 obstructive and 25 nonobstructive, and the organic changes of the mitral leaflet were compared to those of 30 patients with sigmoid interventricular septum. Thirty subjects without cardiac diseases served as the control group. Transthoracic and transesophageal echocardiography were performed in all subjects to measure the following: left ventricular dimension, interventricular septal thickness and peak velocity at the left ventricular outflow tract by transthoracic echocardiography; the lengths and the thicknesses of the rough zone of the anterior and posterior mitral leaflets at mid-diastole and the distance between the tip of the posterior papillary muscle and the anterior mitral annulus by transesophageal echocardiography. The presence of systolic anterior motion of the mitral complex, contact between the anterior mitral leaflet and the interventricular septum during diastole, and the occurrence of mitral valve prolapse (MVP) were also investigated. The maximum area and timing of MR during systole was measured by M-mode color Doppler technique. The following results were obtained. 1. MR was observed in 35 (88%) of the 40 patients with hypertrophic cardiomyopathy. The maximum regurgitant area in the obstructive group was significantly greater than in the other groups, and the regurgitation was frequently pansystolic. 2. The lengths of both mitral leaflets at mid-diastole were significantly greater in both groups with hypertrophic cardiomyopathy than in the other groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1995

Growth of parathyroid gland in uremic patients on maintenance hemodialysis.

High-resolution, real-time ultrasonography was performed in 245 uremic patients on maintenance hemodialysis and the growth of the enlarged parathyroid glands was compared with the clinical and biochemical signs during follow-up periods of 12 months. The total volume of the parathyroid glands was significantly correlated with the serum C-terminal parathyroid hormone (C-PTH; r = 0.379, p = 0.0001) and calcium levels (r = 0.252, p = 0.0224). After 12 months, the total volume of the enlarged parathyroid glands and serum C-PTH or calcium levels were correlated more closely than in the initial study (r = 0.615, p = 0.0001, and r = 0.489, p = 0.0002, respectively). Both the serum C-PTH levels and the total volume of the enlarged parathyroid glands increased significantly (p = 0.0001), while the ratio between the serum C-PTH levels and the volume of the parathyroid glands decreased significantly (p = 0.0001). There was no difference in the clinical and biochemical signs except for the serum aluminum levels between the patients with and without an increased gland volume. These results suggest that the growth of parathyroid glands may progress more rapidly than the increase in the serum PTH levels, independent of the serum calcium levels, in uremic patients on maintenance hemodialysis.

Adolescent↗
PubMed1995

Influence of serum phosphate on the efficacy of oral 1,25-dihydroxyvitamin D3 pulse therapy.

In patients with a moderate degree of renal insufficiency, restriction of dietary phosphate suppresses PTH secretion by increasing serum calcitriol. However, this may not operate in advanced renal failure. The present study was designed to evaluate the influence of serum phosphate levels on PTH secretion in oral 1,25-dihydroxyvitamin D3 [1,25(OH)2D3] pulse therapy. 22 patients with secondary hyperparathyroidism [carboxy-terminal PTH (c-PTH) concentration: 19.5+/-13.9 ng/ml, mean +/-SD] received oral doses of 1,25(OH)2D3 (3.0-4.0 micrograms) twice a week, each at the end of hemodialysis, for 12 weeks. Doses of phosphate binders remained unchanged throughout this period. Patients were divided into two groups: group A (11 subjects) with mean serum phosphate levels of less than 6.0 mg/dl and group B (11 subjects) with levels of 6.0 mg/dl and above. There was no significant difference in the average corrected serum calcium levels. The reduction in serum intact PTH levels was greater in group A than in group B. A negative correlation (r = -0.48; p < 0.05) was observed between mean serum phosphate levels and the percent decrease in serum c-PTH levels. The findings of this study indicate an important role for dietary phosphate reduction in oral 1,25(OH)2D3 pulse therapy and suggest that serum phosphate reduction may play a part in suppressing PTH secretion through a mechanism independent of 1,25(OH)2D3 and plasma calcium levels.

Administration, Oral↗
PubMed1995

[Changes in pulmonary venous and transmitral flow velocity patterns after cardioversion of atrial fibrillation].

The time course of recovery of left atrial mechanical function after electrocardioversion of atrial fibrillation was examined in 25 patients with atrial fibrillation by recording pulmonary venous and transmitral flow velocities and interatrial septal motion during atrial systole within a day (16 +/- 5 hours) and ten days after cardioversion of atrial fibrillation by transesophageal and transthoracic Doppler and M-mode echocardiography. There were 6 patients with hypertension, 4 with ischemic heart disease, 2 with alcoholic heart, 5 with dilated cardiomyopathy, and 8 without underlying heart disease. The peak velocities of the atrial systolic waves of the transmitral and pulmonary venous flow velocities (A and PVA, respectively) and first systolic wave (PVS1) of pulmonary venous flow, durations of both atrial systolic waves, and amplitude of interatrial septal motion during atrial systole increased significantly ten days after cardioversion compared with those measured within a day of cardioversion in all patients except the 5 patients with dilated cardiomyopathy. Peak velocity of the second systolic wave (PVS2) of pulmonary venous flow increased, and that of the early diastolic and diastolic waves (E and PVD, respectively) of transmitral and pulmonary venous flow decreased ten days after cardioversion compared with those within a day of cardioversion. These results suggested that active atrial systolic (A and PVA) and relaxant (PVS1) parameters obtained from transmitral and pulmonary venous flow velocities are good indicators of left atrial mechanical function after cardioversion of atrial fibrillation.

Adult↗
PubMed1995

Reduction of intermediate density lipoprotein by pravastatin in hemo- and peritoneal dialysis patients.

Elevated plasma intermediate density lipoprotein (IDL) is one of the features of uremic dyslipidemia which is potentially atherogenic. We examined the effects of pravastatin, an HMG-CoA reductase inhibitor, on IDL levels as well as other lipoprotein parameters in 19 uremic patients treated with hemodialysis (HD, n = 11) or continuous ambulatory peritoneal dialysis (CAPD, n = 8). The patients were administered 5 mg/day pravastatin for the initial 4 weeks and 10 mg/day for the subsequent 12 weeks. In the analysis of the total subjects, IDL-cholesterol was reduced by 31% as well as low density lipoprotein (LDL)-cholesterol. Cholesterol in very low density lipoprotein (VLDL) also decreased whereas that in high density lipoprotein (HDL) did not. Significant decrease of serum triglycerides was due mainly to reduced IDL- and LDL-triglycerides. Apolipoprotein (apo) A-I did not change, whereas apo A-II, B, C-II, C-III, E, and B/A-I ratio were significantly lowered. Pravastatin did not affect measured activity of lecithin: cholesterol acyltransferase, post-heparin plasma lipoprotein lipase or hepatic triglyceride lipase. HD and CAPD patients responded almost equally to the treatment. IDL elevation was present independent of serum total cholesterol, and it was lowered by pravastatin even in non-hypercholesterolemic subjects. There was no critical adverse effect besides transient and asymptomatic increase of serum creatine kinase level. We conclude that pravastatin can be a safe and effective approach to the management of dyslipidemia in uremic patients who have an elevated level of IDL.

Apolipoproteins↗
PubMed1995

[Neutrophil elastase in postoperative pleural effusion of patients who had undergone pulmonary resections].

We determined whether activity of neutrophil elastase increases in pleural effusion after lobectomy for the neoplasm in the lung. Samples of pleural effusion were obtained 3 and 24 h postoperatively and samples of the peripheral blood were obtained preoperatively, 3 h, 24 h, and 1 w postoperatively, then the neutrophil counts, the levels of neutrophil elastase and alpha 1-antitrypsin by enzyme-linked immunosorbent assay, the activity of neutrophil elastase using succinyl-(L-alanine) 3-p-nitroanilide were measured. We found that the levels of neutrophil elastase increased 170 times greater in pleural effusion than in peripheral blood 3 h after lobectomy. However, the levels of alpha 1-antitrypsin did not increase in pleural effusion. The activity of neutrophil elastase increased to 0.54 +/- 0.1 mumol/min/l in pleural effusion 3 h after lobectomy, however the activity of neutrophil elastase was under the sensitivity level of detection in the peripheral blood after lobectomy. In conclusion, there is an imbalance between the levels of neutrophil elastase and alpha 1-antitrypsin in pleural effusion after lobectomy, the imbalance resulting in the increased activity of neutrophil elastase which probably is relating to tissue injury in the pleural spaces.

Aged↗
PubMed1995

[Surgical treatment of lung cancer over 80 years of age: investigation from post operative complications].

Seventeen patients with lung cancer over 80 years were treated surgically from 1983 through 1993 in our department. Thirteen patients were male and four were female. The histology of the tumor was adenocarcinomas, squamous, large and small cell carcinomas, in 9, 6, 1 and 1 cases, respectively. More than single lobectomy was performed in each patient. Unilateral pulmonary occlusion test was applied in patients whose expected contralateral FEV1.0/BSA was less than 800 ml.m2, or expected residual FEV1.0/BSA was less than 850 ml.m-2. Postoperative cardiovascular complications, such as PAT, PAC, PVC or Af, were seen in 9 patients, respiratory problems, namely, sputa retention, retained secretions or atelectasis, in 7 patients. Blood chemistry and hematology were performed for about three weeks after operations, and found increases in serum transaminases, and leukocytosis. However, there were no operative death. We conclude that some patients over 80 years of age are candidates for surgery after careful cardiopulmonary preoperative evaluation.

Adenocarcinoma↗
PubMed1995

[Immunologic alterations after splenectomy for trauma].

The effects of splenectomy for trauma patients on immunologic function were studied. Various immunologic indices including humoral and cellular immunity were serially measured up to one year in thirteen adult patients with blunt trauma: All the patients recovered from the initial injury and were good health at 12 month except for one died at ten month from unrelated cause. Complements and immunoglobulins decreased following splenectomy, then rapidly increased to normal or above normal levels and maintained the level throughout the one year period. Contrary to previous reports, Ig-M levels were not decreased after splenectomy. Anti-pneumococcal antibody (Pn-ab) was below effective concentration at one year except one case. Lymphocyte subpopulation was characterized by decreased T (OKT-3) cells and inverted helper/suppressor ratio. Lymphocyte blast formation was suppressed before surgery and remained low throughout the period. This study demonstrated that the humoral immunity was reserved after splenectomy, while cellular immunity such as helper/suppressor ratio and lymphocyte blast formation was impaired even one year after injury in most patients. Increased Ig-M levels after splenectomy in this study might suggest different immune response in Japanese. Decreased Pn-ab would justify the use of anti-pneumococcal vaccine after splenectomy for trauma.

Accidents, Traffic↗