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Biomedical subjects

M Aiba

Publications and source records attributed to M Aiba.

At least 73 records · Page 4Linked to original sources
PubMed1994

Test performances of three diagnostic procedures in evaluating thyroid nodules: physical examination, ultrasonography and fine needle aspiration cytology.

A retrospective study was performed to determine the reliability of physical examination (PE), ultrasonography (US) and fine-needle aspiration cytology (FNA) in the evaluation of thyroid nodules. Preoperative diagnoses of 252 euthyroid patients comprised 126 with benign lesions, 114 with papillary carcinoma and 12 with follicular carcinoma made by PE, US and FNA were reviewed. The specificity of PE, US and FNA for malignancy was 98%, 90% and 98%, respectively. The sensitivity of PE, US and FNA for malignancy was 63%, 78% and 80%. The sensitivity for papillary carcinoma of the three procedures was 68%, 83%, 88%, whereas that for follicular carcinoma was 25%, 25%, 8%, respectively. When all the test results were negative, the likelihood ratio favoring papillary carcinoma was 0.008 whereas that favoring follicular carcinoma was 0.6. The histological category of carcinoma should be considered when evaluating diagnostic procedures for thyroid nodules. No negative test result is conclusive for ruling out the possibility of follicular carcinoma.

Biopsy, Needle↗
PubMed1993

Pathogenesis of autoimmune hypothyroidism induced by lymphokine-activated killer (LAK) cell therapy: in vitro inhibition of human thyroid function by interleukin-2 in the presence of autologous intrathyroidal lymphocytes.

Lymphokine-activated killer (LAK) cell therapy frequently results in primary hypothyroidism. To elucidate the responsible mechanism, we investigated the effects of interleukin-2 (IL-2) on thyroid function of cultured human thyroid follicles in the presence or absence of autologous thyroid-derived lymphoid cells (TDLC). Human thyroid follicles, obtained by subtotal thyroidectomy from patients with Graves' disease, were cultured in serum-free medium containing bTSH and various concentrations of human IL-2, with or without TDLC. After 5 days of culture, 125I was added, and after an additional 3 days of culture, 125I incorporated into thyroid follicles and organic 125I (125I-T4 + 125I-T3) released into the culture medium were estimated. In the absence of TDLC, IL-2 did not affect bTSH-induced thyroid function. In the presence of TDLC, however, IL-2 inhibited the bTSH-stimulated thyroid function in a concentration-dependent manner. The minimum IL-2 concentration required to inhibit thyroid function was 1 U/ml. At 100 U/ml, IL-2 inhibited thyroid function completely. IL-2 increased the concentration of IFN-gamma in the culture medium conditioned by TDLC but not by thyroid follicles. When both were cocultured, IL-2 more significantly increased the concentration of IFN-gamma to an extent sufficient for inhibiting thyroid function per se. Furthermore, the addition of anti-IFN-gamma antibody to the medium partially restored the IL-2-inhibited thyroid function. In summary, by coculturing human thyroid follicles and autologous intrathyroidal lymphocytes with IL-2, it was possible to reproduce the thyroid dysfunction associated with LAK cell therapy. Our data indicate that IL-2 inhibits thyroid function, at least partly, by stimulating production of IFN-gamma, a potent inhibitory cytokine for thyroid cells.

Analysis of Variance↗
PubMed1993

IGF-II producing hepatic fibrosarcoma associated with hypoglycemia.

A 67-year-old male was admitted with the complaint of weakness at hunger early in the morning, when blood glucose was less than 40 mg/dl. The abdominal ultrasonogram and computerized tomogram demonstrated a huge tumor in the right liver lobe. Hypoglycemia disappeared after transcatheter arterial embolization. Then hepatic lobectomy was performed. The tumor was histologically shown to be a fibrosarcoma. Insulin-like growth factor-II was intensely stained in the Golgi area of the tumor cells, suggesting its role in the mechanism of hypoglycemia.

Aged↗
PubMed1993

[Single selective cerebral perfusion for aortic arch replacement].

The patients underwent aortic arch replacement for aneurysmal disease from 1988 to 1993 using a simplified cardiopulmonary bypass (CPB) technique with single selective cerebral perfusion (single SCP). Recently cold cerebral perfusion technique was also used. In order to study the effect of this technique, we monitored bilateral carotid artery pressure, blood oxygen saturation of jugular vein and brain oxygenation by near infrared spectroscopy during CPB. Of the ten patients with arch aneurysm, five had urgent operation for ruptured aneurysm. The cold single SCP was accomplished by perfusion to the right axillary artery using separate pump and separate heat exchanger (flow 10-15 ml/kg/min, pressure 40-60 mmHg, perfusion temperature under 12 degrees C) under the low CPB flow (1,000-1,500 ml/min), moderate systemic cooling (23-25 degrees C) and retro-grade cardioplegia. There were no strokes caused by this technique. This simplified technique of cold single SCP was simple and attractive method, provide satisfactory cerebral protection.

Aged↗
PubMed1992

Peculiar nuclear clearing composed of microfilaments in papillary carcinoma of the thyroid.

BACKGROUND: Papillary carcinoma of the thyroid frequently occurs in young women. Four cases of papillary carcinoma were found in women in their 20s, and the disease was characterized by unusual morphologic and clinical features. METHODS: Four cases were analyzed clinically, grossly, microscopically, ultrastructurally, and immunohistochemically and compared with control cases of papillary carcinoma. RESULTS: The tumors histologically showed various appearances with trabecular, solid cribriform, follicular, and papillary patterns. A striking finding was that stratified cancer cell nests with prominent nuclear clearings were scattered in the tumors. Ultrastructurally, the nuclear clearings were composed of fine thread-like fibrils, and they were bound unselectively to various antibodies against hormones and intermediate filaments. The four patients also had common clinicopathologic features as follows: they were all women in their 20s and their preoperative serum thyroglobulin levels were all normal despite the large size of their thyroid tumors. The tumors were grossly well encapsulated, and there was no lymph node metastasis, except in one patient who had only one positive node. CONCLUSIONS: The peculiar nuclear features were distinct from intranuclear cytoplasmic inclusions or ground-glass nuclei, and these have not been reported previously to the authors' knowledge in conventional thyroid neoplasms. These tumors might represent another subtype of papillary thyroid carcinoma.

Actin Cytoskeleton↗
PubMed1992

An insulin-like growth factor II-producing histiocytoma associated with hypoglycemia: analysis of the peptide, its gene expression, and glucose transporter isoforms.

An insulin-like growth factor II (IGF-II)-producing histiocytoma was detected in a patient presenting with the classical findings of tumor-related hypoglycemia (low serum insulin and IGF-I concentrations, glucose intolerance, and only modestly increased serum IGF-II levels). Acid-gel filtration of serum extracts showed a single peak of IGF-II immunoreactivity that emerged at the same site as the 125I-labeled human IGF-II standard. High-performance liquid chromatography (HPLC) analysis of the tumor IGF-II demonstrated that it had an identical retention time to that of recombinant human IGF-II. The tumor IGF-II content was extremely high, messenger RNA (mRNA) for IGF-II showed a 100-fold increase in expression compared with normal human liver tissue. Of special interest, a newly identified exon (hE1) was shown to be predominantly expressed in the tumor by Northern blot analysis using leader exon-specific rat IGF-II complementary DNA (cDNA) probes. Although the significance of this finding remains uncertain, this is the first evidence of a new transcription unit in the human IGF-II gene. In addition, immunoblotting showed that the levels of the glucose transporters, GLUT1 and GLUT4, in the tumor were low and undetectable, respectively. This finding makes it unlikely that increased glucose consumption by the tumor accounted for the hypoglycemia in this patient. This case report provides an interesting insight into the pathophysiology of tumor-induced hypoglycemia and new evidence of the abnormal regulation of IGF-II gene expression in human tumors.

Animals↗
PubMed1992

Malignant fibrous histiocytoma of the auricle: an immunohistochemical and electronmicroscopic study.

Malignant fibrous histiocytoma (MFH) is a soft-tissue tumor of late adult life. This tumor is uncommon in the head and neck region. A case of MFH arising in the auricle is presented with immunohistochemical and electronmicroscopic findings. Histologically the tumor was characterized by numerous spindle cells with abundant eosinophilic cytoplasm and many small capillaries. They were positively stained with vimentin, alpha 1-antitrypsin, and alpha 1-antichymotrypsin. Electronmicroscopically, some tumor cells contained abundant lysosomes and others contained numerous filaments.

Adult↗
PubMed1992

Evaluation of cor pulmonale on a modified short-axis section of the heart by magnetic resonance imaging.

Magnetic resonance imaging (MRI) of a modified short-axis section of the heart, in 36 patients with chronic pulmonary diseases, consisting of 19 patients with pulmonary hypertension (PH group; mean pulmonary arterial pressure > or = 20 mm Hg) and 17 patients without pulmonary hypertension (non-PH group) was evaluated to study the configuration of the right ventricle. Parameters of right ventricular hypertrophy, including right ventricular wall thickness (RVWT) and the ratio of RVWT to left ventricular posterior wall thickness (RVWT/LVPWT), with this method were significantly larger in the PH group than in the non-PH group (p < 0.01). RVWT and RVWT/LVPWT correlated well with mean pulmonary arterial pressure (r = 0.90, p < 0.001 and r = 0.89, p < 0.001), total pulmonary resistance (TPR; r = 0.88, p < 0.001 and r = 0.85, p < 0.001), and pulmonary arteriolar resistance (PAR; r = 0.83, p < 0.001 and r = 0.81, p < 0.001). This method of setting a patient in a supine position and slicing with single-oblique sections may seem overly simple compared with Dinsmore's double-oblique short-axis section of the heart, but it is more convenient in practice. These results suggest that a modified short-axis section of the heart by MRI provides valid clinical configurational information concerning the right ventricle on which to base a noninvasive diagnosis of cor pulmonale.

Adult↗
PubMed1992

Plasma aldosterone response to upright posture and angiotensin II infusion in aldosterone-producing adenoma.

Nineteen patients with primary aldosteronism due to surgically confirmed aldosterone-producing adenoma (APA) were examined to evaluate the response of aldosterone to upright posture and angiotensin II infusion. Upright posture reportedly decreases the plasma aldosterone concentration (PAC) in APA but raises it in idiopathic hyperaldosteronism. However, our findings showed the opposite result, in that the upright posture did not change or raised PAC in 15 of 19 cases (79%). Angiotensin II was infused i.v. at doses from 0.5-2 ng/min.kg body weight in six patients in whom the upright posture raised PAC, but did not raise PAC in all cases. This result supports the assumption that APA is functionally insensitive to angiotensin II. A concomitant rise of ACTH, pretreatment with calcium channel blockade, and other modulating factors may be involved in this PAC rise. Whatever the reason, such a high frequency of patients with increased PAC in APA raises some question about the clinical value of the upright posture test. We believe, then, there is reason to check any interpretation concerning increased PAC in the case of the upright posture test in distinguishing between APA and idiopathic hyperaldosteronism.

Adenoma↗
PubMed1992

Risk factors associated with postoperative persistent hypertension in patients with primary aldosteronism.

BACKGROUND: Unilateral adrenalectomy was performed in 63 patients with primary aldosteronism. During a mean follow-up time of 4.1 years, none of the patients showed recurrence of hyperaldosteronism. However, 24 patients (38%) had persistent hypertension. The purpose of this study was to determine factors responsible for postoperative persistent hypertension. METHODS: A stepwise multivariate logistic regression analysis was performed to assess the combined predictive effects of the clinicopathologic variables. RESULTS: Age, sex, and pathologic findings were the best predictive factors of postoperative persistent hypertension. For a patient aged 50 years or more, the odds of persisting hypertension are 10.6:1, compared with those of a patient under 40 years of age. A male patient appears to have a greater chance of hypertension than a female patient; the odds ratio is 5.9:1. Persistent hypertension develops in patients with multiple adenomas or with an adenoma associated with macronodules more frequently than in those patients with a solitary adenoma; the odds ratio is 8.1. CONCLUSIONS: This study suggests that early surgical intervention at a younger age results in a more favorable outcome for patients with primary aldosteronism. The presence of macronodules in association with an adenoma is a cautious predictor of persistent hypertension after adrenalectomy.

Adrenalectomy↗
PubMed1992

Primary pigmented nodular adrenocortical disease (PPNAD): immunohistochemical and in situ hybridization analysis of steroidogenic enzymes in eight cases.

Primary pigmented nodular adrenocortical disease (PPNAD) is a rare but an interesting adrenocortical disorder associated with ACTH-independent hypercortisolism. We have studied eight cases of the adrenals with PPNAD by immunohistochemistry of all steroidogenic enzymes involved in cortisol biosynthesis (P-45scc, 3 beta-HSD, P-450c21, P-45017 alpha, and P-45011 beta) and also by performing in situ hybridization of P-45017 alpha in seven cases in order to localize the sites of specific steroidogenesis in this unique disorder. Immunoreactivity of all the enzymes examined was intense in almost all of the cells in adrenocortical nodules, especially the cells with abundant eosinophilic cytoplasm in all the cases examined. The internodular cortex, which demonstrated atrophy in five cases, normal appearance in two cases and hyperplasia in one case, was negative for the enzymes with an exception of 3 beta-HSD. Hybridization signals of P-45017 alpha were condensed over the nodules in in situ hybridization study, suggestive of an increased production of the enzyme itself in cortical cells of the nodules. These results may be consistent with autonomous cortisol production by the nodular cells and indicate that almost all of the cells in the nodules produce cortisol, which can also explain the presence of hypercortisolism despite small sizes of adrenals in PPNAD. Immunoreactivity of steroidogenic enzymes is observed in a small cluster of cortical cells with abundant eosinophilic cytoplasm located at the zona reticularis but not in adjacent non-nodular cortex, which may support an abnormal development of the zona reticularis as a possible pathogenesis of this disorder.

3-Hydroxysteroid Dehydrogenases↗
PubMed1992

[Mediastinitis with bilateral empyemas following neck phlegmon].

A 46-year-old male complaining of fever and neck swelling was transferred to our department because of bilateral empyemas in the pleural spaces following neck phlegmon. A culture of the right pleural effusion obtained at his local hospital revealed Gram-positive anaerobic cocci. Chest roentgenogram showed bilateral effusions and widening of the upper mediastinum. Neck roentgenogram confirmed widening of the retropharyngeal space. CT clearly demonstrated a continuous lesion from the neck to the mediastinum and occupying the pleural spaces bilaterally. The patient responded to intravenous antibiotics and tube drainage of the pleural cavities, and was discharged after 10 weeks of hospitalization. Because no mediastinal abscess requiring drainage was recognized on CT, surgical drainage of the mediastinal space was not performed. Sequential CT was used to follow the lesion in the retropharyngeal space, mediastinum and pleural spaces, to check and reposition the tubes for drainage of pleural exudate.

Cellulitis↗
PubMed1992

Bilateral adrenocortical adenomas causing Cushing's syndrome. Report of two cases with enzyme histochemical and ultrastructural studies and a review of the literature.

Patient 1 (a 50-year-old woman) with bilateral adrenocortical adenomas causing Cushing's syndrome underwent right-sided adrenalectomy. After an interval of 4 years 5 months, she underwent left-sided tumorectomy. Patient 2 (a 46-year-old woman) underwent bilateral tumorectomy after a frozen-section diagnosis. Each adrenal contained a single macronodule that consisted of compact cells, clear cells, and oxyphilic cells, which had characteristic enzyme histochemical and ultrastructural features. In addition, the adrenals had a so-called pigmented nodule and extracapsular small focus of compact and clear cell proliferation in case 2. The nonnodular part of the cortex was atrophic in both cases. Fourteen patients (mean +/- SD age, 42.5 +/- 5.55 years) with bilateral adrenocortical adenomas associated with Cushing's syndrome have been described in the literature. Thirteen (93%) of the patients were female. Three patients had unilateral or bilateral multiple adenomas. While the earlier described patients underwent bilateral total adrenalectomy, those in recent reports had part of the adrenal resected unilaterally or bilaterally (ie, tumorectomy). The above features are useful in differentiating bilateral adrenocortical adenoma from other types of bilateral adrenocortical lesions.

Adenoma↗
PubMed1991

Respiratory nicotine absorption in non-smoking females during passive smoking.

The aim of this study was to measure nicotine concentrations in inspired and expired air so as to learn more about respiratory (nasopharyngeal cavity and lung) nicotine absorption from inspired air and to estimate the nicotine intake during passive smoking. A total of 17 young non-smoking women were exposed to experimental passive smoking. Inspired and expired air was sucked at a constant rate into samplers filled with acid-treated diatomite (Uniport-S) to absorb nicotine in the air. Absorbed nicotine was assayed by gas chromatography. The range of nicotine concentration in the inspired air was 40-200 micrograms/m3. In this setting, 47 samples obtained from the 17 subjects were assayed. Nicotine absorption, which was calculated as [(nicotine concentration in inspired air-nicotine concentration in expired air)/nicotine concentration in inspired air] x 100, remained at 60%-80% (mean +/- SD, 71.3% +/- 10.2%) without being affected by the nicotine concentration in the inspired air. From this result, it was estimated that the average intake of nicotine was 0.026 mg/h in a group of non-smokers exposed in a room containing a nicotine concentration of 100 micrograms/m3, which is equivalent to fairly severe involuntary tobacco smoking. This is the first report on the estimation of respiratory nicotine absorption and nicotine intake during passive smoking based on the direct measurement of nicotine concentrations in both inspired and expired air.

Adolescent↗
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

[A study of glomerular damage due to extracorporeal circulation--meaning and usefulness of measuring of urinary microalbumin].

An increase of excretion of urinary microalbumin (U-Alb) is thought to demonstrate earlier glomerular damage than deterioration of Glomerular Filtration Rate (GFR). In this study, the meaning and usefulness of measuring U-Alb before, during and after Extracorporeal Circulation (ECC) was estimated. In 25 cases of adult cardiac surgery, we measured U-Alb, and simultaneously as current indices of glomerular function, serum and urinary creatinine, blood urea nitrogen, serum beta 2-microglobulin, urine volume, and cardiac output were measured. Albumin Excretion Rate (AER) [U-Alb X urine volume] and Albumin Index (AlbI) [U-Alb/U-Cr] were calculated as indices of U-Alb, and Creatinine clearance (Ccr) was calculated as GFR. The changes of each parameter, the correlation AER and AlbI during and after ECC with parameters that relate to ECC, and the assessment of the prolongation of glomerular damage after operation that possibly progress to acute renal failure were investigated. Our results showed AER and AlbI to increase following ECC with high values maintained during and after ECC, in spite of recovery of Ccr, from 24 hours to 4 days postoperatively. AER and AlbI recovered at 7 days and 14 days after surgery, respectively. The existence of glomerular damage, not indicated by a change in Ccr, was indicated by increases of AER and AlbI. The damage was thought to be temporary glomerular dysfunction. In correlation of AER and AlbI with ECC parameters, ECC of long duration influenced the glomerular damage as indicated by an increase of AER and AlbI.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Diffuse sclerosing variant of papillary carcinoma of the thyroid. Clinical importance, surgical treatment, and follow-up study.

A diffuse sclerosing variant is not very rare among papillary carcinomas of the thyroid when the patients are female and younger than 30 years of age. The variant is characterized by diffuse involvement of one or both thyroid lobes, with dense sclerosis, patchy lymphocytic infiltration, and abundant psammoma bodies. Controversy still exists concerning its prognosis. We reviewed our experience with 14 patients treated between 1958 and 1988. All patients were young females, their age being from 10 to 28 years with a mean of 19.6. Hashimoto's thyroiditis had been suspected in nine patients before they came to our clinic. Nowadays the diagnosis of this cancer is possible when we have this entity in mind and detect abundant psammoma bodies either by ultrasonography or by soft-tissue roentgenography of the neck. Total thyroidectomy with modified neck dissection was carried out in eight patients, subtotal thyroidectomy with neck dissection in five, and lobectomy with neck dissection in one. All of them are alive and well without distant metastasis at a mean follow-up of 16 years. Because most of the patients with this variant of papillary carcinoma are young women and the prognosis is favorable, a complete resection without causing later recurrence, but also cosmetic and complication-free surgery, should be considered.

Adolescent↗