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Biomedical subjects

I Ohta

Publications and source records attributed to I Ohta.

At least 37 records · Page 2Linked to original sources
PubMed1994

Non-surgical retrieval of intravascular foreign body: experience of 12 cases.

An intravascular foreign body is an iatrogenic complication that occurs during arterial or venous catheterization or interventional procedures. The foreign body could either be a catheter fragment, a dislodged coil, or a steel guide wire. From January 1987 to December 1992, 12 cases of intravascular foreign-body removals were performed by a percutaneous method at Mackay Memorial Hospital. Of the 12 cases, five were dislodged steel guide wires, four were broken CVP catheters, two were dislodged coils, and one was Port-A fragment. The techniques we used were the loop-snare technique (two cases) and stone basket retriever (10 cases). Eleven cases of intravascular foreign bodies were removed by non-surgical percutaneous retrieval but one case was a failure due to improper extraction of a dislodged steel guide wire. The patient received surgical extraction by regional venotomy finally. No major complications were noted during or after these procedures.

Adolescent↗
PubMed1994

Vascularized heterotopic osteochondral allografts in a rat model following long-term immunosuppression.

The effect of 12 weeks of cyclosporin A (CyA) (7 mg/kg) on the survival of vascularized osteochondral allografts between rat strains--Dark Agouti (DA donor) and Lewis (recipient)--was examined up to 6 months after grafting. Grafts were assessed by India-ink infusion to examine their microcirculation, and by quantitative histology. Isografts (Lewis to Lewis) survived at least 25 weeks, but displayed progressive deterioration due to their non-weight bearing position. Rejection controls (allografts with no immunosuppression) showed rejection within 2 weeks. Allografts in immunosuppressed hosts remained healthy for the 12-week period of immunosuppression, but deteriorated progressively during the ensuing 14 weeks, particularly in the muscle, marrow, and growth plates. Graft repopulation by host cells was assessed by transferring grafts into fresh non-suppressed allograft hosts, following 12 to 26 weeks in the first, immunosuppressed host. All grafts were rejected rapidly following the second transfer, indicating that little or no cellular repopulation of the graft had occurred while in the first host.

Animals↗
PubMed1994

Correlation between event-related potentials and MR measurements in chronic alcoholic patients.

Event-related potentials were recorded in 25 abstinent alcoholics, and 25 gender- and age-matched controls during a two-tone discrimination (odd ball) task. All the subjects were free from medication and dextral. MR images were examined in the alcoholics. The amplitudes of N100, N200 and P300 in the alcoholics were reduced compared with those of the controls. In order to identify morphological changes responsible for ERP abnormalities, linear regression analyses were performed between ERP measures and MRI parameters. The amplitude of N100 was inversely correlated with ventricular size. The amplitudes of P300 were inversely correlated with both ventricular size and width of cortical sulci. It was suggested that the N100 abnormality was related to subcortical structure, and P300 alteration was related to both subcortical and cortical structures in the alcoholics.

Adult↗
PubMed1994

Alteration of immunoreactivity by hydrated autoclaving, microwave treatment, and simple heating of paraffin-embedded tissue sections.

The effects of treatment in a hydrated autoclave (121 degrees C, 2 atm for 20 min), microwave oven (in water), and simple heating (60 degrees C overnight in distilled water or 90 degrees C for 10 min in ZnSO4) on the stainability of 56 antigens by commercially available antibodies in formalin-fixed paraffin-embedded tissue sections were evaluated. The detectability of nuclear antigens, glycoprotein, lymphocytic surface markers, and chromogranin A was significantly and reproducibly improved by these treatments, whereas the detectability of viral antigens and peptide hormones was attenuated or unchanged. This enhancement includes not only the distinctiveness of the positive staining, but also the number of positive cells, as revealed by comparing serial sections. Among these four heating procedures, microwave heating and autoclaving were more effective than the others on p53, c-erbB-2, and CA125, whereas simple heating was best for smooth-muscle actin (HHF35 and CGA7). Generally the effects of the heating procedures for these antigens were consistent among the cases, but the effects on GFAP varied with the case. The alterations we observed could significantly influence the interpretation of immunohistochemical staining of currently popular tumor markers such as p53 in terms of their prevalence (28% vs 64% in gastric cancer; 36% vs 82% in metastatic liver cancer) and other diagnostically important markers.

Antigen-Antibody Reactions↗
PubMed1994

[Determination of synephrine in oriental pharmaceutical decoctions containing evodiae fructus by ion-pair high-performance liquid chromatography].

A simple and precise method was established for the determination of synephrine in oriental pharmaceutical decoctions containing Evodiae Fructus using high-performance liquid chromatography with sodium dodecyl sulfate (SDS) as an ion-pair reagent. Synephrine was eluted within 25 min without interference from co-existing components using an ODS column and a mixture of water-acetonitrile-SDS-phosphoric acid (70:30:0.5:0.1, v/v/w/v) as a mobile phase.

Chromatography, High Pressure Liquid↗
PubMed1994

A histochemical study of the biceps brachii muscle cross-innervated by intercostal nerves. 6 cases of brachial plexus injuries operated with nerve-crossing.

Direct nerve-crossing of intercostal nerves from the lateral thorax to the musculocutaneous nerve was performed in 6 patients after spinal nerve root avulsion with brachial plexus palsy. Elbow flexion power was regained well enough to move against gravity and some resistance in all cases. The muscles were examined histochemically 4 (1-9) years after the operation. The intercostally-innervated biceps brachii muscle showed motor predominance of slow-twitch Type 1 fiber regeneration much more than that of fast-twitch Type 2 fiber in 5 of our patients. Our study suggests that the motor nerves of slow-twitch fibers may have priority in peripheral nerve regeneration over those of fast-twitch fibers.

Adolescent↗
PubMed1994

[The difference between right and left in vitreous findings of normal eyes].

The vitreous in both normal eyes of 671 normal subjects was studied biomicroscopically. The results obtained were as follows: 1. In 618 cases of a refractive error less than -3D (group A) and 53 cases of refractive error over -3D (group B), the incidence of posterior vitreous detachment (PVD) in both eyes increased with age and the absence of PVD in both eyes decreased with age. The percentage of cases with PVD in one eye and no PVD in the other eye was less than 22% in all age groups. 2. There was no significant difference in the degree of vitreous liquefaction between the right and the left eyes. The degree of vitreous liquefaction was also age-related. 3. In the cases with PVD in one eye and no PVD in the other eye, a higher incidence of mild vitreous liquefaction was found in group A than in group B. 4. PVD without collapsed vitreous (simple PVD) in both eyes was observed only in group A. 5. Our results indicated that the vitreous findings in both eyes of an individual were almost identical, and PVD may occur with less vitreous liquefaction in group A than in group B.

Adolescent↗
PubMed1993

Resetting of regional preload due to ventricular shape change alters diastolic and systolic performance.

The diastolic and systolic pressure of one ventricle is increased by an increase in volume and/or pressure of the opposite ventricle; however, a mechanism for the ventricular interaction remains unclear. We hypothesized that the shape change of one ventricle elicited by the opposite ventricle would lead to resetting of the regional length, which may explain the ventricular interaction. We used 15 cross-circulated isovolumically contracting canine hearts in which both ventricular volumes were independently controlled. Diastolic regional segment area was calculated by multiplying circumferential and longitudinal lengths on right ventricular free wall (RVFW; n = 6), interventricular septum (IVS; n = 11), and left ventricular (LV) FW (n = 12). The regional area at relatively small volumes of both ventricles were expressed as 100%. With constant RV volume, increasing LV from 7 to 19 ml increased RV diastolic and systolic pressures by 2.7 and 5.5 mmHg, respectively. Conversely, increasing RV volume increased LV diastolic and systolic pressures by 2.3 and 7.5 mmHg, respectively. Increasing LV volume increased RVFW regional area from 121.0 to 124.6% (P < 0.01) and increased IVS regional area from 103.3 to 108.7% (P < 0.01), whereas the RV volume was held constant. Increasing RV volume also increased LVFW and IVS regional areas from 109.9 to 111.6% (P < 0.01) and from 106.8 to 108.9% (P < 0.05), respectively. Ventricular shape change elicited by ventricular interaction will increase the regional wall area, even though the volume of the chamber is unchanged. The increase in the regional area alters the position of the tissue on its resting and active length-tension relations and, thus, leads to enhancement of the chamber pressure.

Animals↗
PubMed1992

Bile duct stents in the management of hepatolithiasis with long-segment intrahepatic biliary strictures.

Biliary stricture represents a challenging problem in the treatment of hepatolithiasis because of its association with treatment failure and stone recurrence. The long-segment type of stricture is difficult to manage and is likely to recur. To investigate the necessity for biliary stenting after balloon dilatation therapy, 20 consecutive patients with long-segment strictures who had 22 stents (group 1) were compared with ten patients who refused stenting (group 2). The long-segment strictures in group 1 were located on the right side in 80 per cent of patients, on the left side in 10 per cent, and were bilateral in 10 per cent. The stents, varying from 8 to 12 Fr, were retained for at least 6 months. They were inserted through the routes of a matured T tube track (five cases), percutaneous transhepatic track (14 cases), a jejunal limb (two cases) and a fistula (one case). Complications of stenting consisted of dislodgement (one case), haemobilia (two cases), cholangitis (two cases) and intrahepatic abscess (one case). The cumulative probability of stricture recurrence in group 1 was 10 per cent, 15 per cent and 21 per cent at 2, 3 and 4 years, respectively, whereas in group 2 it was 80 per cent at 2 years (P less than 0.003). The results suggest that intrahepatic biliary stenting after balloon dilatation appears necessary and helpful in the management of hepatolithiasis with long-segment biliary strictures.

Adult↗
PubMed1992

[Statistical analysis of relationship between microalbuminuria and diabetic retinopathy].

The relationship between microalbuminuria indicated by the logarithm of the albumin index and the stage of diabetic retinopathy was investigated using 175 diabetic subjects. The relationship and its dependence on the duration and the age of onset of diabetes were analyzed statistically with logistic regression. In younger-onset subjects, microalbuminuria was strongly related to the stage of retinopathy, but in older-onset subjects, the relationship showed to lack. For each subject, the frequency of retinopathy was predicted by the estimated probability calculated with the regression model. When the critical probability was 50%, the sensitivity and specificity were 53.1% and 76.2%, respectively. These results indicated that the regression model using the albumin index might be a useful method to predict the frequency of diabetic retinopathy even without ophthalmoscopic examination.

Adult↗
PubMed1991

Topical use of Xylocaine for relieving vasospasm: effect of concentration.

The spasmolytic and antispasmodic effects of Xylocaine in different concentrations were studied. Twenty-five Wistar rats were divided into five groups according to the concentrations of Xylocaine used (2 percent, 4 percent, 10 percent, 20 percent, and 40 percent). The diameters of rat femoral arteries were measured with vernier calipers under the microscope. Effects were evaluated by the percentage of the test arterial diameter compared with that of the control contralateral artery. Vasospasm of both femoral arteries was produced by administration of the fresh blood of other rats. After immersion in the blood for 10 min. Xylocaine was administered into the right femoral artery for 10 min to examine its spasmolytic effect. The effects of the concentrations shown by the percent diameter were 106 percent, 108 percent, 107 percent, 111 percent, and 106 percent, respectively. There was no significant statistical difference between each agent and its control. Thirty minutes after removal of the agent, 2 percent Xylocaine failed to maintain its spasmolytic effect, while 4 percent, 10 percent, 20 percent, and 40 percent Xylocaine did maintain it. Next, blood was again administered after vessel immersion in the agent to examine its antispasmodic effect. The effects of the concentrations were 100 percent, 114 percent, 124 percent, 152 percent, and 146 percent. There were statistically significant differences, except in the case of 2 percent Xylocaine. Twenty-percent Xylocaine demonstrated a superior antispasmodic effect. The duration of the spasmolytic effect and the antispasmodic effect were concentration-dependent, up to approximately 20 percent.

Animals↗
PubMed1991

The response of left ventricular regional function to afterload stress in patients with old myocardial infarction and ventricular aneurysm.

The functional response of the left ventricle with scar to increased afterload, was examined in 15 patients with old myocardial infarction and left ventricular aneurysm (OMI). Interventional cine left ventriculography during elevating left ventricular pressure with methoxamine. Wall motion was assessed by the radial and the centerline method. Augmented afterload didn't change ejection fraction in patients with OMI, but normalized wall motion (Z) increased in the aneurysmal region and decreased in the remote region in both methods. In the remote region in patients with OMI, afterload stress shortened left ventricular pressure-radial length (P-L) loops along length axis, and reduced percent systolic radial shortening (SS). In the aneurysmal region, P-L loops showed systolic elongation of length at rest and the slope of end-diastolic point to end-systolic point became steeper with increased afterload, resulting in a decrease of aneurysmal expansion. In summary, with increasing afterload, wall motion decreased in non-infarcted regions and increased in aneurysmal regions, in left ventricles with aneurysm. This mechanism may be interpreted as afterload-induced shifts of P-L loops in each region.

Adult↗
PubMed1991

Significant stenosis of coronary arteries in patients with single and multiple vessel diseases without previous myocardial infarction.

To determine what degree of stenosis should be counted as a significant lesion in each of 3 major coronary arteries in classification of the number of vessels involved, coronary arteriographic percent diameter narrowing (by quantitative angiography) was compared with thallium-201 scinitgraphic redistribution on treadmill exercise in 47 patients with evidence of exercise myocardial ischemia and greater than or equal to 50% diameter narrowing (visual assessment) in at least 1 major coronary artery. Severity of exercise-induced myocardial ischemia for the entire left ventricle (assessed by averaged redistribution index) was separated most sufficiently with definition of 63-64% or greater between patient groups with no- and single-, single- and double-, and double- and triple-vessel diseases. Collaterals and intraventricular contractile interaction are possibly the factors making definition more severe in extensive coronary artery disease. Since the visual method gives an overestimation of stenosis, it was concluded that vessel diameter narrowing of 70% or more should be regarded as significant in patients with single and multiple vessel diseases if the visual method is used.

Adult↗
PubMed1990

Segmental diastolic narrowing of epicardial coronary arteries in aortic regurgitation. Phase analysis by quantitative angiography of coronary artery diameter change during cardiac cycles.

A new finding of a segmental narrowing of the left anterior descending coronary artery in diastole (diastolic narrowing: DN) was reported. DN was found in 6 out of 45 patients (13.3%, 5 males, 1 female) with chronic aortic regurgitation (AR). It is likely that aortic regurgitation was more severe in terms of the history of heart failure, regurgitant fraction, left ventricular end-diastolic volume index and pressure, and aortic diastolic pressure in the patients with DN compared with those without DN. The phasic change of DN in cardiac cycles was analyzed by quantitative angiography, and indicated that DN commences at a point in mid-diastole when coronary vascular driving pressure (the instantaneous aortic and LV pressure difference) becomes abnormally reduced, reaches its maximum at end-diastole, and gradually recovers as aortic pressure increases during systole. In two patients, DN was no longer evident after valve replacement. We concluded that DN, a new coronary arteriographic finding, reflects the integrated severity of AR.

Angina Pectoris↗