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Biomedical subjects

Y Hirota

Publications and source records attributed to Y Hirota.

At least 235 records · Page 13Linked to original sources
PubMed1992

Decreased perfusion in myocardial region of normal donor artery secondary to collateral development. Stress 201Tl myocardial emission CT performed in patients with single vessel exertional angina having collaterals.

Thirty-one patients suffering from single vessel exertional angina with collaterals (Group A) were evaluated by stress 201T1 myocardial emission CT (Tl-SPECT) with 16 controls of severely stenotic single vessel exertional angina without collaterals (Group B). Group A included 21 patients (68%) who showed an extensive perfusion defect in double artery myocardial regions, including the normal donor artery myocardial region (DMR). However, there were no such cases in Group B, giving a significant difference between these 2 groups (p less than 0.001). Four patients in Group A, having a perfusion defect both in DMR and in the collateral dependent myocardial region (CMR) underwent a successful percutaneous transluminal coronary angioplasty (PTCA) with disappearance of collaterals. Tl-SPECT findings after PTCA showed no perfusion defect either in CMR or in DMR. This has been explained on the basis that the coronary collaterals stole blood and produced perfusion defect in DMR.

Aged↗
PubMed1992

Giant negative T waves after maxillofacial surgery.

A patient developed strongly negative T waves following anesthesia for maxillofacial surgery. The electrocardiogram was normal preoperatively, except for a single premature ventricular depolarization, and no abnormalities were noted during the operation. Postoperatively, the T wave gradually inverted in almost all leads and approached the criterion of -10 mm for giant negative T waves in V3 2 days postoperatively. The T wave returned to normal approximately 4 months later. Although the T-wave inversion in this patient may have been caused by surgical trauma to the sympathetic nerve supply to the heart or by myocardial infarction, the exact cause remains undetermined.

Anesthesia, Dental↗
PubMed1991

A combination trial of human lymphoblastoid interferon and bestrabucil (KM2210) for adult T-cell leukemia-lymphoma.

Both human lymphoblastoid interferon (HLBI) and bestrabucil, the conjugate of chlorambucil and beta-estradiol, have antitumor activity against adult T-cell leukemia-lymphoma (ATLL). Because an in vitro study showed that these two agents combined had a synergistic antiproliferative effect on MOLT-4 and WI-38VA13 cell lines, the authors evaluated the clinical efficacy of this combination in a pilot study with a poor-risk group of ATLL patients. The patients were treated daily with 6 x 10(6) IU of HLBI subcutaneously and 100 mg of bestrabucil orally. In patients with lymphoma-type ATLL or hypercalcemia, prednisolone also was given daily. Of 12 patients suitable for evaluation, nine had partial responses, one had a minor response, and two had no response. All five patients with skin infiltration and both patients with hypercalcemia responded. A history of prior chemotherapy did not affect the response rate. The time to clinical response was 3 to 16 days (median, 11 days) after initiation of treatment. The response duration was 4 to 108+ weeks (median, 9 weeks), but all patients except one relapsed, even during continuing treatment. No serious side effects were observed. Although the response rate with this combination treatment was high, the response duration was short, and other treatments would have to be added to achieve control of this aggressive disease.

Adult↗
PubMed1991

Intracellular roles of SN-38, a metabolite of the camptothecin derivative CPT-11, in the antitumor effect of CPT-11.

It is known that 7-ethyl-10-[4-(1-piperidino)-1-piperidino]carbonyloxycamptothecin (CPT-11), a semisynthesized derivative of camptothecin (CPT), has a potent antitumor activity in vivo, but 7-ethyl-10-hydroxycamptothecin (SN-38), a metabolite of CPT-11, shows much stronger cytotoxicity in vitro than CPT-11. In this study, we demonstrated that the relaxation of SV40 DNA plasmids by type I DNA topoisomerase prepared from P388 murine leukemia cells was inhibited by 50% by SN-38 at approximately 1 microM, although CPT-11 at 1 mM slightly inhibited the relaxation. SN-38 and CPT showed strong, time-dependent inhibitory activity against DNA synthesis of P388 cells. However, CPT-11 weakly inhibited DNA synthesis independently of time with coincident inhibition of the total thymidine uptake by the cells. By alkaline and neutral elution assays, it was demonstrated that SN-38 caused much more frequent DNA single-strand breaks in P388 cells than did CPT-11. The same content of SN-38 and a similar frequency of single-strand breaks were detected in the cells treated with SN-38 at 0.1 microM or with CPT-11 at 100 microM. Therefore, single-strand breaks by CPT-11 seem to be due to SN-38 produced from CPT-11 in cells. These results indicate that CPT-11 itself possesses a marginal antiproliferative effect but that SN-38 plays an essential role in the mechanism of action of CPT-11.

Animals↗
PubMed1991

[Clinical evaluation of per-rectal scintigraphy using I-123 IMP--evaluation of the portal hemodynamic changes after TAE].

Per-rectal portal scintigraphy using I-123 IMP was performed before and after TAE in 29 patients with hepatoma. Index of porto-systemic shunt (PSS index) was obtained by lung/(lung + liver) uptake ratio at 30 min after administration of IMP. The influence of TAE on portal circulation was evaluated by using this PSS index. PSS index increased 16 of 29 patients (55.2%) after TAE. PSS index increased after TAE especially in cases of severe liver dysfunction before TAE, marked portal involvement, and embolization of a larger liver volume. PSS index also increased when there was deterioration of esophageal varices, ascites, and hepatic coma after TAE. PSS index is useful for evaluation of portal circulation after TAE.

Amphetamines↗
PubMed1991

Efficacy and safety of clentiazem in patients with essential hypertension: results of an early pilot test.

The purpose of this study was to evaluate the antihypertensive effect of a new calcium antagonist, clentiazem, on inpatients or outpatients with essential hypertension. After blood pressure was stable and greater than 160/95 mmHg with placebo for at least a 2-week observation period, oral clentiazem was administered once daily and dosage was increased stepwise from 10 to 40 mg over 10 weeks. Blood pressure significantly decreased by the second week of the study, and this hypotensive effect was maintained until the eighth week. Cumulative effective rate (percent of patients whose blood pressure decreased in 20/10 mmHg) in 62 outpatients were as follows; 10.3% at 10 mg, 39.6% at 20 mg, 70.2% at 30 mg, 76.6% at 40 mg. There was no significant postural change observed in the blood pressure from supine to standing position. Side effects such as dizziness, general malaise and gait disturbances were observed in 3 (3.9%) of 76 patients. No abnormal changes in clinical laboratory examinations or electrocardiograms were caused by clentiazem. Thus these data demonstrated that clentiazem produces certain antihypertensive effects with sufficient safety.

Adult↗
PubMed1991

Serum and urinary human heart fatty acid-binding protein in acute myocardial infarction.

A competitive enzyme immunoassay (C-EIA) was developed for the measurement of serum and urinary levels of human heart fatty acid-binding protein (hh-FABP), and the appearance and time-course changes of hh-FABP levels were evaluated in patients with acute myocardial infarction (AMI). Control serum and urinary hh-FABP levels, which were determined in 86 serum and 42 urine samples from 86 patients without AMI, were found to range between 0 and 2.8 ng/mL. Serial determinations performed on 11 patients with AMI demonstrated that hh-FABP levels were significantly elevated in the first serum and urine samples obtained within 14 h of the onset of clinical symptoms. Two serum and 2 urine samples obtained only 1.5 h after the onset of symptoms already showed elevated hh-FABP levels, while in the same serum samples the activity of the myocardial-specific isoenzyme of creatine kinase (CK-MB) was still normal. Maximal serum and urinary hh-FABP levels appeared between 5 and 10 h after symptoms developed, and fell sharply towards normal thereafter. The hh-FABP levels in serum and urine both peaked earlier than the elevation of CK-MB activity in serum. The presence of hh-FABP in serum and/or urine seems to be a marker for myocardial damage and could be used as a useful tool for the early diagnosis of AMI.

Adolescent↗
PubMed1991

Left ventricular midwall mechanics in systemic arterial hypertension. Myocardial function is depressed in pressure-overload hypertrophy.

BACKGROUND: Left ventricular (LV) midwall geometry has been described conventionally as the sum of the chamber radius and half of the wall thickness; this convention is based on the assumption of uniform transmural thickening during systole. However, theoretical considerations and experimental data indicate that the inner half (inner shell) of the LV wall thickens more than the outer half (outer shell). Thus, an end-diastolic circumferential midwall fiber exhibits a relative migration toward the epicardium during systole. As a result, the conventional method provides an overestimate of the extent of the midwall fiber shortening. METHODS AND RESULTS: We developed an ellipsoidal model with a concentric two-shell geometry (nonuniform thickening) to assess midwall fiber length transients throughout the cardiac cycle. This modified midwall method was used in the analysis of LV cineangiograms from 15 patients with systemic arterial hypertension and 14 normal subjects. Study groups were classified according to LV mass index (LVMI): 14 normal subjects (group I), eight hypertensive patients with a normal LVMI (group II), and seven hypertensive patients with an increased LVMI (group III). There were no significant differences in LV end-diastolic pressure or volume among the three groups; the ejection fraction was slightly greater in group II (70 +/- 5%) than in groups I (65 +/- 8%) and III (66 +/- 4%), but this trend did not achieve statistical significance. Values for endocardial and conventional midwall fractional shortening (FS) were also similar in the three groups. By contrast, FS by the concentric two-shell geometry (modified midwall method) in group III (16 +/- 2%) was significantly less than that seen in groups I and II (21 +/- 4% and 21 +/- 5%, respectively; both p less than 0.05). This difference achieves greater importance when it is recognized that mean systolic circumferential stress was lower in group III (151 +/- 22 g/cm2) than in groups I and II (244 +/- 37 g/cm2 and 213 +/- 38 g/cm2, respectively; both p less than 0.01). The midwall stress-shortening coordinates in six of the seven group III patients were outside the 95% confidence limits for the normal (group I) subjects. Thus, despite a normal ejection fraction, systolic function is subnormal in hypertensive patients with LV hypertrophy. CONCLUSIONS: Chamber dynamics provide an overestimate of myocardial function, especially when LV wall thickness is increased. This is due to a relatively greater contribution of inner shell thickening in pressure-overload hypertrophy.

Cardiomegaly↗
PubMed1991

Involvement of leukotriene B4 in ovulation in the rabbit.

The present study was undertaken to assess the effects of lipoxygenase products on ovulation, oocyte maturation, and steroid production in the perfused rabbit ovary preparation. Ovulatory efficiency was significantly reduced when rabbit ovaries were perfused with human CG (hCG) plus nordihydroguaiaretic acid (NDGA) at 10(-5) or 10(-6) M, as compared to contralateral hCG-treated controls. The addition of NDGA to the perfusate inhibited hCG-induced ovulation in a dose-related manner. The percentage of ovulated ova and follicular oocytes achieving germinal vesicle breakdown did not differ significantly between NDGA-treated ovaries and contralateral controls. Leukotriene B4 (LTB4) production by the perfused rabbit ovaries reached its maximum 6 h after exposure to hCG and then declined. The addition of NDGA at 10(-5) M significantly inhibited hCG-stimulated LTB4 production by rabbit ovaries throughout the entire perfusion periods. The ovulatory efficiency in ovaries treated with hCG alone or with hCG plus NDGA correlated significantly with LTB4 production by perfused rabbit ovaries 6 h after exposure to hCG (alpha = 0.8893, P less than 0.01). Furthermore, the addition of LTB4 at 100 ng/ml to the perfusate reversed the inhibitory effects of NDGA on hCG-induced ovulation. However, exposure to NDGA affected neither progesterone nor estradiol production elicited by hCG administration. These results suggest that NDGA may block hCG-induced ovulation in vitro, probably via the inhibition of LTB4 production by rabbit ovaries.

Animals↗
PubMed1991

Clinical assessment of left ventricular systolic function by force-length and stress-shortening relationships.

Left ventricular (LV) systolic function was assessed in patients with hypertensive heart disease (HHD, n = 30), hypertrophic cardiomyopathy (HCM, n = 27), dilated cardiomyopathy (DCM, n = 25), volume overload heart (VOH, n = 31) and normal subjects (NS, n = 32) in the two-dimensional framework of force-length (end-systolic stress-end-systolic volume index) and stress-shortening (mid-systolic stress-ejection fraction). Quadratic discriminant analysis revealed that the ellipses of confidence of HHD and normal subjects were in the same place with regard to both force-length and stress-shortening, while all other groups were well-discriminated. Three subgroups of patients, those with DCM with mild heart failure and those with VOH (with and without heart failure), were easily distinguishable on the basis of stress-shortening, but not on the basis of force-length measurements. It is concluded that LV systolic function and afterload are maintained within the normal range under pressure and volume overload until symptoms of heart failure appear via the mechanism of compensatory hypertrophy. Stress-shortening appears to be a more useful parameter than force-length for the analysis of LV systolic function in clinical practice.

Adult↗
PubMed1991

Immunochemical studies on the combining sites of bovine immunoglobulins reactive with invertase.

Calcium-dependent and -independent bovine IgG reactive with invertase were isolated by affinity chromatography on invertase-coupled Sepharose 4B and their specificities were determined by competitive binding assays. The binding of 125I-labeled calcium-dependent and -independent bovine IgG reactive with invertase to invertase-coupled Sepharose 4B were most effectively inhibited by invertase and mannan. The binding was more weakly inhibited by mannose, glucose, and methyl alpha-D-mannopyranoside, whereas that was much more weakly inhibited by other monosaccharides and glycoproteins. These findings suggest that the combining sites of calcium-dependent and -independent bovine IgG reactive with invertase may be specific for invertase and/or mannan.

Animals↗
PubMed1991

Immunochemical specificities of the combining sites of bovine immunoglobulins reactive with sepharose 4B.

Binding specificities of calcium-dependent and -independent bovine IgM and IgG reactive with unsubstituted Sepharose 4B were determined by competitive binding assays. The binding of 125I-labeled calcium-dependent bovine IgM to unsubstituted Sepharose 4B was most effectively inhibited by lactose which was about 100 times more reactive than galactose and melibiose. Other inhibitors were much less potent. With 125I-labeled calcium-independent bovine IgM and IgG, on the other hand, lactose was as potent as galactose. Melibiose was about 10 times less potent than lactose and galactose, whereas other mono- and disaccharides were much less potent. From these findings, the combining site of calcium-dependent bovine IgM reactive with unsubstituted Sepharose 4B may be specific for lactose, whereas those of calcium-independent bovine IgM and IgG specific for galactose.

Animals↗
PubMed1991

[Blow-out fractures of the orbit--imaging modalities and therapeutic results].

Thirty-four cases of blow-out fracture were evaluated by high-resolution CT, Hess test for red and green color and synoptophore. The results of these tests were compared with the final outcome of the fractures. The fractures were classified on the basis of the location (floor, medial wall or roof), extent (total, partial or linear) and type of fragments (punched-out or trapdoor). The medial wall type included many cases (33%) with no complaint of double vision, and many cases with a combination of disturbances in ocular mobility in both the horizontal and vertical directions. The floor type showed a low incidence of disturbances in ocular movement in the horizontal directions. Regarding the extent of the fracture, all cases with the total type showed disappearance of double vision within three months. Many of the partial and linear types had a poor outcome. With regard to the type of fragments, all of the trapdoor type cases showed a favorable result with disappearance of double vision within three months. Some of the punched-out type cases, however, showed a poor outcome.

Adolescent↗
PubMed1991

[A case report of lymphoepithelial cyst in the parotid gland].

A 57 year-old Japanese male was seen with the chief complaints of left parotid gland swelling, pain, trismus. At the initial visit, a subcutaneous mass, measuring 50 x 70mm, was seen in the left parotid region. The mass was moderately tender and the consistency was soft anteriorly and elastic firm posteriorly. The mobility was restricted with no change in the skin covering the mass. The saliva from the left parotid gland was normal in colour and contents. Various imaging modalities were done preoperatively including CT, MRI, ultrasonography and aspiration biopsy under the ultrasonographic guide. None was thus conclusive for the differential diagnosis and our tentative diagnosis was a cystic lesion in the parotid gland. A partial parotidectomy was performed under general anesthesia and the cystic lesion, measuring 20mm in diameter, was found in the deep lobe. The cyst showed no connection to the external ear canal, and tracts and fistulae were absent. Histopathological report lead to the definite diagnosis of lymphoepithelial cyst. A mild and incomplete facial palsy on the left had been noted for more than 10 years and this, however, improved after the surgery.

Humans↗
PubMed1991

[Isolated medial orbital wall fracture and late fronto-ethmoidal mucocele].

Twenty-one cases of isolated medial orbital wall fractures were reported and CT findings by coronal planes were evaluated as to the effects of fractures upon the ethmoidal cells and nasal meati. Three coronal planes, which respectively contain such structures as Agger nasi, Pars membranacea and superior meatus, were selected for the study. The extent of fracture was evaluated by dividing the medial wall into three equal portions, i.e., superior, middle and inferior. The prolapsed volume was evaluated in three classes of occupying 1/3, 2/3 and 3/3 of the ethmoid. The presence of soft tissue density was recorded at the three surfaces, upper, medial and lower, around the prolapsed orbital content. The extent of the fracture was most often seen in such cases as involving all the three divisions in 41.3%. The prolapsed volume occupying 1/3 was seen in 28, 6%, and 2/3 in 23.8%. The presence of soft tissue density was seen in 38.1% of upper surface, in 36.5% of medial, and 11.1% of lower. Summarizing the total effects of the fractures, the coronal plane containing Pars membranacea was most severely damaged followed by the plane of the superior meatus. Two rare cases of fronto-ethmoidal mucoceles, caused by the traumas of 23 and 14 years before respectively, were also included and reported. The ophthalmological prognosis was favorable in 90.5% of cases by observations extending more than 6 months. Five cases were surgically treated including two cases of mucoceles.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗