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Biomedical subjects

A Hirayama

Publications and source records attributed to A Hirayama.

At least 19 recordsLinked to original sources
PubMed1992

Temporal increase in resting coronary blood flow causes an impairment of coronary flow reserve after coronary angioplasty.

Impaired coronary flow reserve immediately after coronary angioplasty may be attributed to an increase in resting coronary blood flow. To test this hypothesis we measured great cardiac venous flow (GCVF) at rest and during rapid atrial pacing before and immediately after angioplasty in 22 patients with significant narrowing of the left anterior descending artery and 12 patients (control group) with minimal narrowing. A follow-up (6 months) study was also done in seven patients. Immediately after angioplasty the coronary flow reserve (peak GCVF during pacing/resting GCVF) was not fully restored (1.5 +/- 0.36 before angioplasty, 1.76 +/- 0.42 after angioplasty, and 2.13 +/- 0.33 in the control group). Resting coronary vascular resistance (2.4 +/- 0.9 mm Hg/ml/min) was significantly decreased after angioplasty (2.0 +/- 0.8 mm Hg/ml/min), whereas coronary vascular resistance during rapid pacing was fully restored to normal. Resting hyperemia was restored 6 months later, whereas coronary vascular resistance during pacing was unaltered. In five patients, however, slight ischemic ST-T changes were observed during rapid pacing, even after successful angioplasty associated with a decrease in the lactate extraction ratio. These results indicate that the impaired coronary flow reserve immediately after angioplasty may be attributed mainly to the temporal but significant increase in resting coronary flow, although impaired coronary vascular response to augmented myocardial oxygen demand may also be partially involved.

Aged↗
PubMed1992

Adverse effects of epinephrine in patients with advanced left ventricular dysfunction: analysis of ventriculo-arterial coupling.

We examined the response of ventriculo-arterial coupling to epinephrine in 19 patients with normal left ventricular function and with left ventricular dysfunction of various degrees using a conductance catheter. They were divided into three groups: group I, seven patients without left ventricular wall motion abnormality; group II, six patients with ejection fraction of 45-60%; group III, six patients with ejection fraction of 28-40%. Changes in the slope of the end-systolic pressure-volume relationship (end-systolic elastance), the effective arterial elastance, the ratio of effective arterial elastance to end-systolic elastance and the ventricular work efficiency during administration of two different doses of epinephrine (0.05 and 0.1 micrograms/kg/min) were compared among the three groups. At baseline there were no significant differences among the three groups in the ratio of effective arterial elastance to end-systolic elastance, or ventricular work efficiency. At the lower dose of epinephrine, the mean ratio of effective arterial elastance to end-systolic elastance decreased and the mean ventricular work efficiency increased in any groups. At the higher dose of epinephrine the mean ratio of effective arterial elastance to end-systolic elastance further decreased and the mean ventricular work efficiency further increased in groups I and II. However, the mean ratio of effective arterial elastance to end-systolic elastance did not decrease but the mean ventricular work efficiency even decreased in group III. Thus, in patients with advanced left ventricular dysfunction, even a high dose of epinephrine does not modulate the ventriculo-arterial coupling to increase ventricular work efficiency.

Aged↗
PubMed1992

Role of atrial contraction and synchrony of ventricular contraction in the optimisation of ventriculoarterial coupling in humans.

OBJECTIVE: To examine the effects of pacing modes on the interaction between the left ventricle and arterial system in humans. DESIGN: The slope of the end systolic pressure-volume relation (end systolic elastance), effective arterial elastance, the ratio of effective arterial elastance to end systolic elastance, and mechanical energy efficiency were compared under different pacing modes (atrial, atrioventricular, and ventricular). PATIENTS: Nine male patients with sick sinus syndrome who had cardiac catheterisation for diagnosis and to see whether they needed a pacemaker. INTERVENTIONS: A conductance catheter with tip-manometer was inserted into the left ventricle to obtain pressure-volume loops, and two pacing catheters were inserted into the right atrium and into the right ventricle respectively. RESULTS: End systolic elastance was lower in atrioventricular pacing than in atrial pacing, but effective arterial elastance was not significantly different. End systolic elastance was lower in ventricular pacing than in atrioventricular pacing, and effective arterial elastance was higher in ventricular pacing than in atrioventricular pacing. Consequently the ratio of effective arterial elastance to end systolic elastance was lowest in atrial pacing and highest in ventricular pacing, and mechanical energy efficiency was highest in atrial pacing and lowest in ventricular pacing. CONCLUSIONS: Atrial contraction and synchronous ventricular contraction independently optimise ventriculoarterial coupling in terms of a transfer of energy. Thus atrial pacing gives the best ventriculo-arterial coupling among these pacing modes.

Adult↗
PubMed1992

Organic structures of the hypercalcified peritubular matrix in horse dentine.

EDTA-insoluble organic structures of the hypercalcified peritubular matrix (PM) in horse dentine were observed by scanning electron microscopy. The PM was enveloped in double cylindrical structures composed of fibrillar sheaths in the inner and outer peripheries. Between the outer fibrillar sheath and intrinsic fibrils of the intertubular matrix, a calcified cementing membrane existed. Within the PM, warped cone-shaped structures of fibrillar sheaths, overlapping at intervals of 4-6 microns and semiconcentrically surrounding the dentinal tubule, extended from the inner fibrillar towards the outer fibrillar sheath. The cone-shaped fibrillar sheaths following the inner and outer fibrillar sheaths were identified as the incremental lines of the PM. Most of these fibrils may be collagen although it could not be confirmed, whereas non-collagenous organic materials in the lateral branches of the dentinal tubule are radially arranged in the PM. These EDTA-insoluble structures were three-dimensionally illustrated using an image-analysing system.

Acid Etching, Dental↗
PubMed1991

Adrenocorticotropic hormone-independent bilateral adrenocortical macronodular hyperplasia as a distinct subtype of Cushing's syndrome. Enzyme histochemical and ultrastructural study of four cases with a review of the literature.

Four patients with adrenocorticotropic hormone (ACTH)-independent bilateral adrenocortical macronodular hyperplasia (AIMAH) were examined. All of them were men whose ages ranged from 37 to 52 years. Plasma cortisol levels were high, with a loss of diurnal rhythmicity, and plasma ACTH was undetectable. Adrenal cortisol secretion was not suppressed by dexamethasone, but it was ACTH responsive. Test results for corticotropin-releasing hormone (CRH) also were negative. Image analyses revealed a normal sella turcica and significantly enlarged adrenal glands, which showed enhanced uptake of isotope. Both adrenal glands in all cases were between 72 and 176 g in combined weight and were composed of, and distorted by, yellow nodules. Histologically, small cortical cells with or without lipid, occasional clear cells, and rare compact cells of the usual size were increased in number in the glandular cords. Enzyme histochemically, cortical cells showed weaker activity for 3 beta hydroxysteroid dehydrogenase and other enzymes than did usual cortisol-producing adenomas. Ultrastructurally, they had moderately to poorly developed smooth endoplasmic reticulum. Nonnodular areas of the cortex consisting of nonproliferating cells were atrophic and contained no compact cell zone. This is similar to the adrenal cortices attached to cortisol-producing adenomas. These features are unique to AIMAH and suggest the presence of a distinct subtype of Cushing's syndrome.

Adrenal Cortex↗
PubMed1991

Serial transcardiac lactate metabolism in post-reperfused stunned myocardium in evolving myocardial infarction.

To elucidate the relationship between lactate metabolism following reperfusion and restoration of left ventricular (LV) function, we assessed serial changes in transcardiac lactate metabolism following reperfusion therapy in 67 patients admitted to hospital within 6 h of the onset of acute anteroseptal myocardial infarction. Left ventriculograms taken about 30 min after reperfusion therapy revealed marked dyskinesis in the anteroapical region in all subjects. According to the regional ejection fraction (rEF), determined 4 weeks later as an index of LV function, patients were divided into 3 group: 1) Restored LV group: 28 patients with reperfusion and restored LV function (rEF greater than 30%); 2) Poor LV group: 26 patients with reperfusion but poor LV function (rEF less than 30%); 3) Failure group: 13 patients with failed reperfusion and occluded left anterior descending coronary artery. Although there was no difference in elapsed time and time to peak creatine phosphokinase (CPK) between the former 2 groups, the Restored LV group demonstrated lower peak CPK values, suggesting that these patients had less myocardial injury. Immediately after reperfusion, both groups showed transcardiac lactate production. In the Restored LV group, aerobic lactate metabolism was restored early after reperfusion (at 6 h), while in the Poor LV group prolonged anaerobic lactate metabolism was observed. These results suggest that an early restoration of aerobic metabolism might be a sign of stunned and viable myocardium, and a sustained lactate production might relate to a sustained process of myocardial injury.

Adult↗
PubMed1991

Tumor thrombus and microvascular invasion as prognostic factors in renal cell carcinoma.

The significance of two types of vascular invasion (macroscopic tumor thrombus into the renal vein or vena cava inferior and microvascular invasion) as prognostic factors in renal cell carcinoma is analyzed in 121 patients treated at the Department of Urology, Nara Medical University. The data indicate there to be close correlations between tumor thrombus, microvascular invasion and distant metastasis. In patients with tumor thrombus, however, the prognosis is not as poor when surgical removal of the tumor thrombus is successfully performed as when it is not. In contrast, the prognosis of patients with positive microvascular invasion is significantly worse than that of those with a negative finding. Microvascular invasion appears to be a significant prognostic factor in renal cell carcinoma in addition to well-known factors such as tumor stage, tumor grade, tumor thrombus and distant metastasis. To detect microvascular invasion, the histological examination should be extended to give as much detail as possible.

Adult↗
PubMed1991

[A case of retroperitoneal pleomorphic lipoma].

A 71-year-old male patient was referred to our department for further examination for right retroperitoneal tumor. Exploration was done through a flank approach and the tumor with right adrenal gland was removed. A pleomorphic lipoma was diagnosed histopathologically. There have been 8 reported cases of pleomorphic lipoma including our present case in Japan and we discuss the pathogenesis and treatment of this rare disease.

Aged↗
PubMed1991

[A case of squamous cell carcinoma of the urinary bladder associated with bladder calculi].

A case of squamous cell carcinoma of the urinary bladder associated with a bladder stone in a 43-year-old man is reported. Because a 1 cm x 1 cm sized mass was found in the right lateral side of the dome at the time of vesicolithotomy, partial cystectomy was performed. The weight of the stone was 285 g and the tumor was histologically diagnosed as squamous cell carcinoma, grade 2, pT2. Radical cystectomy with ileal conduit was sandwiched by a total of 6 cycles of chemotherapy with PVB. Twelve cases of squamous cell carcinoma of the urinary bladder associated with a bladder stone(s) from the Japanese literature are reviewed, and the relationship between bladder stone, leukoplakia and squamous cell carcinoma discussed.

Adult↗
PubMed1990

Flow cytometric DNA analysis of parathyroid tumors. Implication of aneuploidy for pathologic and biologic classification.

The previous cytometric studies on parathyroid tumors have provided conflicting data regarding the relationship between DNA content and histopathology, resulting from differences in technical methods and data analysis. This study measured nuclear DNA of parathyroid tumors by flow cytometry in fresh material and determined whether DNA aneuploidy really assists in making a pathologic diagnosis of carcinoma or not. From May 1987 through April 1989, 65 consecutive patients operated on for primary hyperparathyroidism had DNA analysis of the freshly excised parathyroid tumors. Three of the patients had metastatic lesions of parathyroid carcinoma in the lung, cervical lymph nodes, and lung and mediastinal lymph nodes, respectively. Pathologic classifications of the lesions from the other 62 patients were 54 adenomas, four carcinomas, and four hyperplasias. In all the latter patients, hyperplasia was associated with a multiple endocrine neoplasia syndrome. Unequivocal evidence of aneuploidy was found in all of the metastatic lesions and 60% of the primary lesions of the carcinomas, in 9% of the adenomas and in 50% of the hyperplasias. Therefore, parathyroid carcinomas were more apt to be aneuploid than were adenomas (P = 0.0015, both-sided testing). In each of the cases of aneuploid hyperplasia, a small aneuploid peak was found. The high incidence of aneuploidy in patients with multiple endocrine neoplasia type 1 may indicate the presence of clonal heterogeneity of hyperplastic glands and the presence of an abnormal subset of cells that have malignant potential. Cell distribution analysis did not provide any significant information beyond ploidy level. In conclusion, DNA flow cytometric analysis of DNA ploidy patterns is a valuable adjunct to the histopathologic diagnosis of parathyroid neoplasms.

Adenoma↗
PubMed1990

Flow cytometric DNA analysis of parathyroid tumors with special reference to its diagnostic and prognostic value in parathyroid carcinoma.

The nuclear DNA content of paraffin-embedded parathyroid tumors from 49 patients with proven primary hyperparathyroidism was determined by flow cytometric analysis. The lesions included 14 primary and 11 locally recurrent or metastatic lesions from 16 carcinoma patients, 28 single adenomas from 28 patients, and 15 hyperplastic glands from five patients with familial multiple endocrine neoplasia type 1. No abnormal DNA stemline was found in any of the hyperplastic glands. One (3.6%) of the adenomas was aneuploid. There was no difference in ploidy patterns between the primary and recurrent lesions of the carcinomas and five (31%) of the carcinomas expressed aneuploidy. Four of the five patients with aneuploid carcinoma had recurrences including pulmonary metastases. One of them died of this disease 12 years after the initial operation, and all except one of the others are hypercalcemic even after removal of the successive recurrent or metastatic tumors. Of the 11 patients with diploid carcinoma, four had either local recurrence or pulmonary metastasis. Two of them are living with normocalcemia 3 and 6 years, respectively, after removal of the recurrent tumors and the others are alive with mild hypercalcemia. The remaining seven patients with diploid carcinoma, however, have no recurrence 2 to 5 years after the initial operation. Thus aneuploid parathyroid carcinomas are likely to show more malignant behavior than those with a diploid DNA pattern. All of the patients with adenoma and hyperplasia have been normocalcemic after a mean follow-up interval of 37 months. This study indicates that flow cytometric analysis of nuclear DNA content is a valuable adjunct to histologic examination in the diagnosis of parathyroid carcinoma and the prediction of the clinical outcome.

Adenoma↗
PubMed1990

Augmented enkephalin-immunoreactivity in adrenaline-producing phaeochromocytomas.

Immunohistochemical studies for methionine- and leucine-enkephalin were performed on 26 phaeochromocytomas to elucidate the patho-physiological roles of enkephalins. Positive reactions were seen in all phaeochromocytomas with varying intensities. The location of methionine- and leucine-enkephalin agreed fairly well with each other. Stronger immunostaining was obtained in phaeochromocytomas secreting both adrenalin and noradrenaline than in those secreting predominantly noradrenaline. Paroxysmal hypertension was frequently observed in patients with adrenalin-secreting phaeochromocytomas, especially those with marked enkephalin positivity. Urinary excretion of metanephrine was significantly correlated with enkephalin positivity. These findings show that all phaeochromocytomas retain the ability to produce enkephalins of the adreno-medullary or extra-medullary chromaffin tissues from which they derive. Augmented enkephalin-immunoreactivity in adrenalin-producing phaeochromocytomas may be interpreted as reflecting a close association of enkephalins with adrenalin under physiological conditions.

Adrenal Gland Neoplasms↗
PubMed1990

Clinical assessment of specific enzyme immunoassay for the human cardiac myosin light chain II (MLC II) with use of monoclonal antibodies.

A highly specific enzyme-linked "sandwich" immunoassay was developed for determining cardiac myosin light chain II (MLC II) in serum by using an anticardiac MLC II monoclonal antibody and a solid phase consisting of glass rods coated with another monoclonal antibody. We can detect as little as 0.2 ng of cardiac MLC II per assay. The measurable range of cardiac MLC II concentration in serum is 1 to 30 micrograms/L. The assay demonstrated no cross-reactivity with a skeletal muscle MLC within the measurable range. The mean coefficients of variation were 6.1% within assay and 5.1% between assay. The concentration of cardiac MLC II in sera from healthy subjects ranged from 0 to 4.0 micrograms/L (mean 0.75 micrograms/L and median 0 micrograms/L). The concentrations of cardiac MLC II in serum of patients with skeletal muscle disease due to various causes (n = 15) and patients with effort angina (n = 25), in general, were not significantly elevated above normal. In all patients with myocardial infarction, the concentrations of cardiac MLC II were over 4.0 micrograms/L at 12 h after onset. The mean (+/- 1 SD) peak concentration of cardiac MLC II was 16.2 (+/- 4.4) micrograms/L at 90 h (mean) after onset. On the 5th day, the cardiac MLC II concentrations in all patients with myocardial infarction were significantly elevated above normal; none showed abnormal MB-creatine kinase (CK-MB) activity at this time. Thus, the measurement of cardiac MLC II concentration in serum may be useful to provide a specific and sensitive diagnosis of myocardial necrosis at any time period following myocardial infarction.

Adult↗
PubMed1990

Primary adrenocortical micronodular dysplasia: enzyme histochemical and ultrastructural studies of two cases with a review of the literature.

The adrenal glands from two patients with primary adrenocortical micronodular dysplasia (PAMD) were studied (no. 1, a 23-year-old man with cardiac myxomas and sarcoidosis; no. 2, a 16-year-old girl). The PAMD cells showed intense activity of 3 beta-hydroxysteroid dehydrogenase (3 beta DH), succinate DH, glucose-6-phosphate DH, alkaline phosphatase (AlPase), and other DHs and lysosomal hydrolases, giving a characteristic staining pattern. The staining patterns correlated well with ultrastructural findings. The larger adrenals (no. 1: 16.6 g) were associated with larger black nodules and internodular cortex (INC) with fairly well-retained enzyme activities, and contained cell clusters and single cells with intense AlPase activity with the appearance of PAMD nodules in the buds. The smaller adrenals (no. 2: 5.4 g) were associated with smaller black/yellow nodules, and had INC with weaker enzyme activity. Analysis of descriptions of INC in 25 previously reported cases revealed that the larger adrenals (more than 10 g) had less atrophic INC than the smaller ones. The characteristic enzyme pattern in PAMD cells explains the paradox that PAMD adrenals smaller than normal can cause Cushing's syndrome, and may be useful for investigating neoplastic and non-neoplastic counterparts in other adrenal lesions. The relationship between PAMD cells and INC is not simply one of autonomy versus atrophy, and both cell types may be stimulated by a certain common trophic factor. Thus, PAMD belongs to the category of hyperplasia.

3-Hydroxysteroid Dehydrogenases↗
PubMed1990

[Is emergency angioplasty following successful thrombolysis more effective than thrombolysis alone in acute myocardial infarction?].

This study clarified the effects of residual stenosis following successful thrombolysis in acute myocardial infarction on infarct size and cardiac function in the chronic stage. Subjects consisted of 24 patients with acute anteroseptal myocardial infarction within six hours after the onset of symptoms, in whom thrombolysis was performed, and additional coronary angioplasty was performed in 10 patients. Great cardiac venous flow (GCVF) at a point 30 min after thrombolysis and angioplasty was examined by continuous thermodilution, and the minimal cross-sectional area (MCSA) was determined at a stenotic lesion using an orthogonal angiographic view. As an index of infarct size, we measured abnormally contracting segments (ACS) and perfusion defects (PD) in 201T1 single photon emission computed tomograms four weeks after the onset. We determined anterior regional ejection fraction (rEF) as an index of left ventricular performance in the chronic stage. The patients with thrombolysis alone and the patients with angioplasty were comparable as to age, gender elapsed time, GCVF, MCSA, ACS, PD and rEF. In all the patients, MCSA did not correlate significantly with GCVF. In the patients with additional angioplasty, MCSA significantly increased (from 0.3 +/- 0.3 mm2 to 2.5 +/- 1.6 mm2). However, GCVF did not necessarily increase in all the angioplasty patients. In four patients having delays in angiographic flow, and MCSA less than 0.1 mm2, there was a significant increase in GCVF after angioplasty (41.3 +/- 32.0 vs 82.0 +/- 60.7 ml/min). GCVF correlated significantly with ACS, PD, and rEF, but MCSA did not correlate significantly with them. We concluded that in patients with successful thrombolysis but without angiographic filling delay, emergency angioplasty for residual stenosis has no effect on further limitation of infarct size.

Adult↗