Biomedical subjects

T Aihara

Publications and source records attributed to T Aihara.

At least 91 records · Page 5Linked to original sources

PubMed1994

Preoperative Discrimination of Fibroadenoma Which Is Clinically and Cytologically Indistinguishable from Breast Carcinoma through Clonal Analysis of Fine Needle Aspirate of Tumor: Report of a Case.

Recently, it has been demonstrated that breast carcimoma is monoclonal and fibroadenoma is polyclonal in origin. In the present case report, this observation was successfully applied to a preoperative differential diagnosis of a fibroadenoma clinically and cytologically indistinguishable from carcimoma. Case report: A45-year old female presented for clinical examination with a history of breast lump. A firm tumor measuring 2 x 2 cm was palpable in the upper-outer quadrant of @the left breast. The margin of the tumor was partially ill-defined and its mobility was restricted. A tumor shadow with a partially ill-defined margin was revealed by mammography. Ultrasonographic examination showed and irregularly-shaped, hypo-echoic tumor accompanied by an acoustic shadow. Fine needle aspiration biopsy yielded positive cytology. Based on these results, the tumor was diagnosed as breast carcinoma. However, clonal analysis of fine needle aspirates showed a polyclonal pattern, strongly indicating that the tumor was not a carcinoma but benign disease; most probably fibroadenoma. Thus, an open surgical biopsy was performed. Histoglogical examination revealed that the tumor was indeed a fibroadenoma with epithelial hyperplasia. This case suggests the usefulness of clonal analysis of fine needle aspirates in differentiating fibroadenoma from carcinoma of the breast.

Journal Article↗

PubMed1994

Temporal pattern sensitivity of long-term potentiation in hippocampal CA1 neurons.

High-frequency electrical stimulation in the hippocampus leads to an increase in synaptic efficacy that lasts for many hours. This long-term potentiation (LTP) of synaptic transmission is presumed to play a crucial role in learning and memory in the brain. However, the frequency of stimulation generally used to obtain LTP is beyond the normal physiological range of activity of hippocampal neurons. We found that LTP can be induced by an electrical stimulation whose frequency is comparable to that of the naturally occurring firing activity of hippocampal neurons if the stimulating pulse-interval train has a special time structure. In the present experiment, we compared the magnitude of LTP induced by the four types of stimuli which have the same pulse number and the same mean frequency but different time structure in interstimulus intervals. One type of stimuli has regular intervals, and this served as a control stimulus. In the other three types of stimuli, the adjacent interstimulus interval had the following statistical properties: in type 1, their correlations are positive; in type 2, negative; and in type 3, independent. The magnitude of LTP induced by these four types of stimuli showed clear order relationships: type 3/type 1 >> control > type 2. Detailed analysis of the evoked potential during a period of temporal pattern stimulation revealed that the amplitude of the population spikes of repetitive firing, especially of the second and third population spikes, had the same order relationship as the LTP.(ABSTRACT TRUNCATED AT 250 WORDS)

2-Amino-5-phosphonovalerate↗

PubMed1994

Clonal analysis of regenerative nodules in hepatitis C virus-induced liver cirrhosis.

BACKGROUND/AIMS: Based on histological criteria, regenerative nodules in cirrhotic liver have been generally considered to result from hyperplastic proliferation of hepatocytes. Whether these nodules are hyperplastic or neoplastic has not been determined definitively. This study examined the issue by clonal analysis of each nodule. METHODS: The method for clonal analysis was based on restriction fragment length polymorphism of the X chromosome-linked phosphoglycerokinase gene and on random inactivation of the gene by methylation. RESULTS: Clonality of hepatocellular carcinoma (n = 7) and regenerative nodules (n = 76) induced by hepatitis C virus infection was analyzed. All carcinomas were monoclonal. Clonal analysis of regenerative nodules showed that 43% (33 of 76) were monoclonal in origin. Adjacent monoclonal nodules showed inactivation of the same allele of phosphoglycerokinase gene. Because the gene allele is inactivated at random, it is unlikely that each nodule happens to inactivate the same allele; it is more likely that monoclonal cell expansion is initiated before the nodule is established by septum formation. CONCLUSIONS: Monoclonal cell expansion is seen in a considerable number of regenerative nodules in cirrhotic liver. The results indicate that certain genetic changes, which are required for hepatocarcinogenesis, have already occurred in these nodules.

Base Sequence↗

PubMed1994

Magnetic resonance angiography in the management of childhood moyamoya disease: first choice for neurovascular scrutiny.

We performed magnetic resonance angiography (MRA) in 12 children with a suspected or angiographically proven moyamoya disease. MRA was performed by the three-dimensional, time-of-flight technique and, successfully depicted the primary abnormalities in the distal carotid arteries in 10 out of the 12 patients. In the other two patients, poor visualization of the intracranial vasculature strongly suggested the presence of the disease. On MRA, moyamoya vessels were visible in eight patients. The presence of anastomoses was also confirmed by MRA in seven of the 10 patients who had undergone encephalo-duro-arterio-synangiosis. Our findings suggest that MRA may be the tool of choice for selecting patients to undergo conventional angiography. However, establishing a definite diagnosis still requires some improvements in the delineation of the fine vasculature.

Adolescent↗

PubMed1994

Restenosis after successful emergency coronary angioplasty for acute myocardial infarction: comparison with elective angioplasty.

We investigated the initial and late restenosis rate after successful emergency coronary angioplasty in 64 patients with acute myocardial infarction, and compared these results with those of 100 patients (110 lesions) who had successful angioplasty on an elective basis. The majority of the baseline clinical and angiographic variables were similar in the myocardial infarction and elective groups. The restenosis rate at 1 month was high in patients undergoing emergency angioplasty for acute myocardial infarction (23 vs. 12%). At 3-6 months, the angiographic restenosis rate was low for the infarction group (26 vs. 37%). The overall restenosis rate was similar in the infarction and elective groups (39 vs. 40%). Lesion regression after coronary angioplasty was more frequent in the infarction than in the elective angioplasty group (27 vs. 14%, P < 0.05). These findings suggest that considering the high restenosis rate at 1 month and the lower, but still 20% or more, rate at 3-6 months, a follow-up angiography should be performed both prior to discharge and at 3-6 months after the procedure, in patients with acute myocardial infarction.

Aged↗

PubMed1994

Characteristic bright signal of parotid pleomorphic adenomas on T2-weighted MR images with pathological correlation.

The purpose of this study was to correlate the MR features and histological findings of pleomorphic adenomas, which are the most common tumour of the parotid gland, and to distinguish them from other types of tumour in the parotid gland. The materials studied consisted of 20 pleomorphic adenomas, including 12 untreated and eight recurrent cases, 17 other benign parotid tumours, and 12 malignant tumours. T1- and T2-weighted images and Gd-DTPA enhanced T1-weighted images were obtained. Characteristic bright signals with a higher intensity than that of CSF were seen in all of the pleomorphic adenomas on T2-weighted images, and were found to represent myxoid areas histologically. Although the cystic spaces in some benign tumours produced bright signals, these areas were distinguished from myxoid areas due to nonenhancement with Gd-DTPA. No bright signals were seen in the malignant tumours. In conclusion, bright signals on T2-weighted images represent myxoid tissue and are useful findings for diagnosing pleomorphic adenomas.

Adenolymphoma↗

PubMed1994

Hepatic calcification in an anicteric patient with biliary atresia after hepatic portoenterostomy.

Hepatic calcification was found in an anicteric infant with biliary atresia after hepatic portoenterostomy. When she was 2 years of age, ultrasonography detected an echogenic structure with acoustic shadowing. Computerized tomography located it at the proximal portion of Segment 6 in the right lobe. Although both techniques failed to exhibit dilatation of the peripheral bile ducts, we believe intrahepatic cholelithiasis provides the most likely diagnosis. Although seven cases with biliary atresia were reported to have this complication, all of them were icteric when the diagnosis was confirmed. The patient should be carefully followed up since the succeeding stones may cause jaundice by obstructing the main duct.

Biliary Atresia↗

PubMed1994

[A case of multiple nodular pulmonary amyloidosis associated with Sjögren's syndrome].

A 58-year-old female, who had complained of dryness of the conjunctiva and mouth for nine years, was admitted to our hospital because chest X-ray films revealed increases in both the size and the number of pulmonary nodules in comparison to four years earlier. Histological findings of the salivary gland biopsy confirmed a diagnosis of Sjögren's syndrome. An open lung biopsy was performed. Histologically, the pulmonary nodules consisted of homogeneous, acellular eosinophilic materials, which were identified as amyloid by Congo red staining. Immunohistochemical examination showed the amyloid to be composed of AA protein. There were no deposits in other organs. Peribronchial lymphocytic infiltration associated with Sjögren's syndrome was present. Nodular pulmonary amyloidosis with Sjögren's syndrome is very rare condition. To our knowledge, this case is only the ninth to be reported in the literature.

Female↗

PubMed1994

[Clonal analysis of human breast tumors by means of polymerase chain reaction].

Clonal analysis has been done using the method based on restriction fragment length polymorphism of the X-chromosome-linked phosphoglycerokinase gene and on random inactivation of the gene by methylation. Introduction of polymerase chain reaction (PCR) of this method has enabled clonal analysis of minute lesions. Utilizing this PCR-based method, clonality of a variety of human breast tumors (breast carcinoma, fibroadenoma, phyllodes tumor, intraductal papilloma, and atypical ductal hyperplasia) was studied in the present investigation in order to obtain valuable information on the histogenesis of these tumors.

Base Sequence↗

PubMed1994

[Experience with operation for synchronous multiple primary lung cancer].

We presented a 66-year-old man with synchronous double cancers developing in the right upper lobe, which were diagnosed preoperatively. He underwent right upper lobectomy with hilar and mediastinal lymphadenectomy. Post-operative patho-histological study showed two different histologic types of cancer; one was undifferentiated carcinoma of the small cell type, and the other was moderately differentiated adenocarcinoma.

Adenocarcinoma↗

PubMed1994

[Brain perfusion in acute infantile hemiplegia studied with single photon emission computed tomography].

Sequential examinations of single photon emission computed tomography (SPECT) were performed on a 5-month-old boy with acute infantile hemiplegia from the acute ictal stage. SPECT was performed with technetium-99m-hexamethyl-propylene-amineoxime during the status when the patient had left-hemiconvulsions (status epilepticus) and on the 3rd, 7th and 10th day after the status. During the ictal stage and the 3rd day after the status, diffuse hyperperfusion was revealed in the right hemisphere, while diffuse hypoperfusion was exhibited in the right hemisphere on the 7th and 10th day after the status. Hypoperfusion in the corresponding hemisphere, after the status, has been reported in patients with acute infantile hemiplegia. There has, however, been no report of ictal brain perfusion. The pathogenesis of this hyperperfusion is not clear, but alteration of brain perfusion in this patient, especially in acute phase, may help to elucidate the etiology of acute infantile hemiplegia.

Brain↗

PubMed1993

Unilateral perihilar opacification caused by lightning.

The chest radiographs of two children struck by lightning showed right perihilar opacification. The radiographs were taken 2 h and 5 h after the event respectively. To our knowledge no similar cases have been reported.

Child↗

PubMed1993

Sclerosing hemangioma of the lung: pathological study and enzyme immunoassay for estrogen and progesterone receptors.

Sclerosing hemangioma of the lung is a rare benign neoplasm of uncertain histogenesis. In this study, thirteen cases of sclerosing hemangiomas were analyzed by immunohistochemistry for various histochemical markers including surfactant apoprotein. The pale cells were shown to share several immunohistochemical markers with epithelial lining cells and were suggested to be immature cells differentiating toward epithelial lining cells. Electron microscopic study failed to characterize the exact nature of pale cells, but it disclosed the precise structure of large lamellar bodies, which are frequently present in the cystic spaces of sclerosing hemangioma. These large lamellar bodies had common morphological characteristics to lamellar inclusion bodies of type II pneumocytes or epithelial lining cells. Eight cases of sclerosing hemangioma obtained freshly at surgery had a quantitative analysis of estrogen and progesterone receptors performed by enzyme immunoassay. The value of estrogen receptors ranged from 0 to 7.8 fmol/mg protein. In addition to this quantitative analysis, the immunohistochemical study demonstrated estrogen receptors mainly in the pale cell nuclei of several sclerosing hemangiomas. Estrogen receptors may play an important role in growth, differentiation and surfactant production in the sclerosing hemangioma.

Adult↗

PubMed1993

[A case of life-threatening ventricular arrhythmias probably due to psychotropic drugs].

We present a case provoked life-threatening ventricular arrhythmias probably due to psychotropic drugs. The patient was a 55-year-old man who had previously twice operations of aortic valve replacement (AVR). The signs of cardiac failure were recurrently appeared from the end of 1991, and he had received promethazine and sulpiride for his depressive state. From cardiac catheterization, we planned his third AVR. The electrocardiographic (ECG) QTc interval was prolonged to 0.48 seconds on this admission. In March 1992 syncopal attack appeared suddenly, and his monitor ECG revealed frequent polymorphous ventricular tachycardia (VT) and Torsade de Pointes (Tdp). These arrhythmias stopped by emergent cardiac pacing. After discontinuing these psychotropic drugs, no ventricular arrhythmias appeared. Since the patient complained severe insomnia one month before operation, the diminished dose of psychotropic drugs (promethazine and levomepromazine) was readministered. Ten days after the operation, syncopal attack reappeared and his ECG recorded frequent VT and Tdp. During both syncopal attacks his serum potassium and magnesium were within normal limits. Two days later, he died from multi-organ failure. We concluded that life-threatening arrhythmias such as VT and Tdp might develop under the administration of mild psychotropic drugs (promethazine or levomepromazine), therefore, must better take a care of ECG changes in cases of using any psychotropic drugs.

Electrocardiography, Ambulatory↗

PubMed1993

Anorectal anomaly in Pfeiffer syndrome.

A Japanese girl with Pfeiffer syndrome is described. She has clinical and radiological manifestations typical of the syndrome. In addition, she had an imperforate anus not described previously in the syndrome. This seems to expand the phenotype associated with Pfeiffer syndrome or represent a new acrocephalosyndactyly syndrome.

Acrocephalosyndactylia↗

PubMed1993

[Within-day and day-to-day variations of serum M-CSF levels in healthy volunteers].

We have investigated on within-day and day-to-day variations of serum M-CSF levels in healthy volunteers (ranges of age: 20-21 years old). M-CSF levels in serum were measured using enzyme-linked immunosorbent assay (ELISA). Serum M-CSF levels in early morning were 1.31 +/- 0.30 ng/ml (mean +/- SD, n = 10) in male volunteers, 1.50 +/- 0.13 ng/ml (n = 10) in female volunteers. No significant difference was observed between male and female volunteers in serum M-CSF levels. No significant within-day variations in serum M-CSF levels were also observed. Serum M-CSF levels in period of thirteen days in each individual person were almost constant (n = 5). The inverse correlation was observed between M-CSF levels and number of neutrophils. The correlation, however, was not observed between M-CSF levels and number of monocytes. The present results suggest that there are mechanisms in vivo which maintain serum M-CSF in a constant level in each individual person.

Adult↗

PubMed1993

[Two cases of acute myocardial infarction with simultaneous occlusions of two main coronary branches].

We report two rare cases of acute myocardial infarction with simultaneous occlusion of two main coronary branches. Case 1 was a 66-year-old man. Emergent CAG demonstrated total occlusions of RCA-segment 1 and LCX-segment 13. The patient underwent a direct PTCA of the RCA occlusion and an intracoronary infusion of urokinase. Angiography before discharge revealed a 25% stenosis of the RCA and a 75% stenosis of the LCX. Case 2 was a 68-year-old man. His ECG showed ST elevation in inferior and anterior leads. Emergent CAG demonstrated a 99% stenosis of RCA-segment 1 and total obstruction in LAD-segment 6. The distal LAD was not visualized by antegrade and retrograde flow from collaterals. We considered the state of hyper-coagulability and reducing of coronary blood flow as the mechanism of simultaneous occlusions in our cases.

Aged↗

PubMed1992

Gonadotropin-induced up- and down-regulation of ovarian follicle-stimulating hormone (FSH) receptor gene expression in immature rats: effects of pregnant mare's serum gonadotropin, human chorionic gonadotropin, and recombinant FSH.

The actions of gonadotropins on ovarian differentiation are associated with dynamic changes in gonadotropin receptor content, presumably due to modulation of receptor gene expression. The present studies used a reverse transcription-polymerase chain reaction to obtain a rat FSH receptor cDNA fragment, followed by synthesis of a labeled cRNA probe to examine the regulation of FSH receptor mRNA levels during follicular maturation, ovulation, and luteinization. Northern blot analysis of ovarian RNA with the FSH receptor probe revealed two predominant hybridization signals of 7.0 and 2.5 kilobases (kb) as well as minor signals of 4.2 and 1.8 kb. Treatment of immature rats with PMSG (10 IU) to induce follicular development resulted in increased FSH receptor mRNA levels 24 h after treatment, with a further increase at 52 h, coincident with increased [125I]FSH binding. Subsequent treatment with an ovulatory dose of hCG decreased FSH binding and receptor mRNA levels by 6 h, with a maximal inhibition at 24 h after hCG. In luteinized ovaries obtained 3 and 5 days after hCG treatment, the 7.0-kb FSH receptor mRNA increased again, but no concomitant elevation of [125I]FSH binding was detected. We recently demonstrated that FSH treatment alone is capable of inducing follicular growth and ovulation, thus providing a unique model to evaluate the effects of FSH on regulation of its receptor gene. Immature hypophysectomized estrogen-treated rats were implanted with an osmotic minipump delivering recombinant human FSH (rcFSH; 4 IU/day) to stimulate follicle growth, followed 52 h later with a single injection (20 IU) of rcFSH to induce ovulation. Stimulation of follicular growth with rcFSH increased both FSH receptor binding and mRNA levels. In contrast, the ovulatory dose of rcFSH decreased FSH binding and receptor message levels within 12 h. Thus, gonadotropin regulation of ovarian FSH receptor content during follicular growth, ovulation, and luteinization is associated with similar changes in FSH receptor message levels. Also, studies using rcFSH demonstrate that both up- and down-regulation of FSH receptor gene expression can be induced by the homologous hormone at different stages of follicle development.

Animals↗