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Biomedical subjects

T Akasaka

Publications and source records attributed to T Akasaka.

At least 109 records · Page 6Linked to original sources
PubMed1997

The role of mel-18, a mammalian Polycomb group gene, during IL-7-dependent proliferation of lymphocyte precursors.

mel-18 is a mammalian homolog of Drosophila melanogaster Polycomb group genes. Mice lacking the mel-18 gene show a posterior transformation of the axial skeleton, severe combined immunodeficiency, and a food-passing disturbance in the lower intestine due to hypertrophy of the smooth muscle layer. In this study, the severe combined immunodeficiency observed in mel-18 mutant mice is correlated with the impaired mitotic response of lymphocyte precursors upon interleukin-7 stimulation. Strikingly, the axial skeleton and lymphoid phenotypes are identical in both mel-18 and bmi-1 mutants, indicating that the Mel-18 and Bmi-1 gene products might act in the same genetic cascade. These results suggest that mammalian Polycomb group gene products are involved in cell cycle progression in the immune system.

Animals↗
PubMed1997

Neonatal lupus erythematosus occurring in identical twins.

The patients were one-month-old identical twins. Scaly erythema was noted mainly on the trunk, face, and scalp of one twin starting about three weeks after birth and starting about two weeks after birth in the other. The patients' courses were observed without treatment; the eruptions tended to disappear two months after birth. The mother had a past history of transient facial erythema. Both twins and mother were positive for antinuclear antibody, anti-SS-A antibody, and anti-SS-B antibody. The histopathological findings corresponded to those of discoid lupus erythematosus (DLE). The class of HLA typing revealed Cw3 in both twins, which is frequently observed in neonatal lupus erythematosus (NLE), and A24 in the mother, which is frequently observed in mothers of babies with NLE.

Autoantibodies↗
PubMed1997

A possible case of eccrine poroma arising in seborrheic keratosis with partial intermediate malignancy and tumor of the follicular infundibulum.

An eighty-year-old woman presented with a eccrine poroma that appeared to have arisen in a seborrheic keratosis lesion on the right side of her abdomen. The tumor consisted of a brownish, flat, elevated lesion with an eroded nodule at its periphery. Histopathological analysis of the flat, elevated lesion revealed benign basaloid and squamoid cells that showed acanthotic upward proliferation, suggesting a seborrheic keratosis. The eroded nodule showed irregular proliferation of slight atypical squamoid cells with, in parts, ductal structures in the upper dermis, suggesting that it was an eccrine poroma with partial intermediate malignancy. In addition to the eroded nodule, an occult tumor clinically accompanied the seborrheic keratosis. Histopathology of the occult tumor revealed fenestrated columns and cords of pale epithelial cells attached to the base of the seborrheic keratosis lesion, which was diagnosed as a tumor of the follicular infundibulum. Although reports of seborrheic keratosis transforming into a sweat gland tumor are rare, the present case suggests that seborrheic keratosis may develop into benign or malignant adnexal tumors, including sweat gland and follicular tumors. Thus, seborrheic keratosis should be considered as a possible precursor of adnexal tumor.

Aged↗
PubMed1997

Cutaneous mixed tumor containing ossification, hair matrix, and sebaceous ductal differentiation.

A 58-year-old Japanese male presented with a cutaneous mixed tumor containing ossification and hair matrix differentiation on the left side of the chin. Histologically, the tumor consisted almost exclusively of apocrine-type epithelial ductal structures and chondroid stroma. Strands and aggregation of basaloid cells which contained keratinous cystic structures with a column of shadow cells arising from basophilic basaloid cells, sebaceous duct-like structures, and ossification in the stroma were also evident. These findings suggest that cutaneous mixed tumors with ossification and hair matrix differentiation are related to both the whole hair follicle and the sweat apparatus.

Adenoma, Pleomorphic↗
PubMed1997

Trichoblastoma with rippled-pattern.

The following is a case study of a 36-year-old Japanese man with a trichoblastoma which exhibited a rippled-pattern on the left temporal region of the scalp. The histological findings of the tumor revealed lobular aggregations composed of immature follicular basaloid cells, lobules of squamous eddy-like foci of incomplete keratinization or small keratinous cysts, and multiple papillary mesenchymal bodies similar to hair germ. Interestingly, a rippled-pattern of basaloid cells and hyalinized matrixes resembling the Verocay bodies of neurilemmoma was also observed. We propose that the rippled-pattern of the basaloid cells and hyalinized matrices is caused by the characteristic stromal induction of trichoblastoma.

Adult↗
PubMed1997

Two cases of basal cell carcinoma arising in seborrheic keratosis.

The present study reports two cases of basal cell carcinoma arising in seborrheic keratosis. The first case is a seventy-three-year-old female who presented with a blackish nodule arising from a pigmented lesion on her chest. Histopathological analysis of the nodule and the pigmented lesion revealed a basal cell carcinoma with hair follicular differentiation and an acanthotic seborrheic keratosis, respectively. The second case is a seventy-year-old female with a blackish nodule arising from a pigmented lesion on her back. Histological analysis of the nodule revealed an atypical basaloid cell mass surrounded by a seborrheic keratosis lesion. In addition to the coexisting seborrheic keratosis with the basal cell carcinoma, a basaloid follicular hamartoma that showed multiple hamartomatous hair follicles or small cysts replaced by a branching cord or lace-like network of basaloid cells surrounded by fibrovascular stroma was identified. We concluded that both cases presented a rare combination of a seborrheic keratosis which underwent a malignant change to basal cell carcinoma. It appears that both basal cell carcinomas and seborrheic keratosis may derive from a similar source: pluripotential cells of either the epidermis or hair follicle epithelium.

Aged↗
PubMed1997

A case of pigmented dermatofibrosarcoma protuberans (Bednar tumor).

The present paper reports a 67-year-old male with pigmented dermatofibrosarcoma protuberans (Bednar tumor) on his right shoulder. The lesion had recurred twice. Clinically, the lesion was a reddish-brown, exophytic, multilobular, firm nodule with an irregular surface, which measured 6.4 x 4.2 cm. Histologically, the proliferated fibroblasts showed a cartwheel pattern and stained positively with CD34, similar to those of a common dermatofibrosarcoma protuberance. However, many melanin-bearing cells that were positive for the S-100 protein were found intermingled among the tumor cells. Based on these findings, we concluded that the clinical manifestations, level of malignancy, and cytological features, as well as the exception of melanin-bearing dendritic cells associated with pigmented dermatofibrosarcoma protuberans, suggest a common dermatofibrosarcoma protuberans. This supports the hypothesis that pigmented dermatofibrosarcoma protuberans is a pigmented variant of dermatofibrosarcoma protuberans. Thus, this type of tumor is not benign, but is an intermediate malignant tumor.

Aged↗
PubMed1997

Pigmented epidermal cyst.

A 58-year-old Japanese woman with a pigmented epidermal cyst on the upper arch of the right external ear is described. The blue appearance of the cyst was striking and uncommon in Japanese. Histologically, abundant melanin pigment was observed in the keratinous mass of the cavity, and epithelial cells showed epidermoid keratinization. Increased numbers of melanocytes in the basal layer, large globular cells of melanocytic origin in the spinous layer, and hair-germ-like aggregates of basaloid cells and melanocytes were also observed. The blue clinical appearance is probably due to the rich melanin granules in the cyst, keratinous mass, keratinocytes, and hair-germ-like structures.

Ear, External↗
PubMed1997

Three-dimensional echocardiographic evaluation of configuration and dynamics of the mitral annulus in patients fitted with an annuloplasty ring.

BACKGROUND AND AIMS OF THE STUDY: Three-dimensional (3D) echocardiography permits the objective analysis of structures and of pathologic conditions of complex geometry. Multiplane transesophageal echocardiography (TEE) permits 3D image sets of the heart to be produced from multiple 2D images by rotating the transducer, without changing its position. The purpose of this study was to clarify the capability of 3D echocardiography to evaluate the configuration and dynamics of the mitral annulus in patients fitted with an annuloplasty ring. METHODS: Twenty patients who underwent mitral valve repair for pure mitral regurgitation (10 with a flexible Duran ring and 10 with a rigid Carpentier ring) were studied. Using a multiplane transesophageal probe, sequential tomographic images were obtained by rotating the transducer at 2 degrees angular intervals around a 180 degrees arc. 3D reconstructions were performed to produce dynamic 3D images of the mitral annulus in a manner that simulated visualization from the left atrium. Mitral annular configuration was assessed from volume-rendered display and extractive 3D imaging. Mitral annular area change was evaluated from selected long-axis cut planes. RESULTS: The configuration and dynamics of the mitral annulus were visualized by 3D displays. In patients with a Duran ring, the mitral annulus had a non-planar configuration and mitral annular area changed during cardiac cycle (increased in diastole; reduced in atrial and ventricular systole; percentage reduction 25 +/- 2%). In patients with a Carpentier ring, the mitral annulus had a planar configuration and mitral annular area was effectively unchanged during the cardiac cycle. CONCLUSIONS: 3D echocardiography using a multiplane transesophageal probe is useful in evaluating the configuration and dynamics of the mitral annulus in patients fitted with an annuloplasty ring.

Adult↗
PubMed1997

[Evaluation of left ventricular ejection fraction using an automated contour tracking method: comparison with equilibrium radionuclide angiography].

A recently developed contour tracking method provides automated edge detection of left ventricular endocardium without a region of interest. The accuracy of this automated contour tracking (ACT) method in the evaluation of left ventricular ejection fraction was assessed in 20 patients (16 males and 4 females, mean age 58 years) using both the ACT method and equilibrium radionuclide angiography. Ejection fractions measured by the ACT method correlated well with those measured by equilibrium radionuclide angiography (y = 0.8x + 11.9, r = 0.91, SEE = 4.0%, p < 0.01). The ACT method provides an accurate estimate of left ventricular ejection fraction.

Echocardiography↗
PubMed1997

Long distance polymerase chain reaction for detection of chromosome translocations in B-cell lymphoma/leukemia.

To establish a rapid and sensitive method to detect neoplastic cells carrying a specific chromosomal translocation in B-cell lymphoma/leukemia, we have developed a novel strategy based on long distance polymerase chain reaction (LD-PCR) amplification. Genomic DNA were extracted from tumor cells carrying a t(14;19)(q32;q13), a t(8;14)(q24;q32), a t(3;22)(q27;q11), a t(2;3)(p12;q27), and a t(3;14)(q27;q32). Oligonucleotide primer pairs were designed to be complementary to exons or flanking sequences of the BCL3, c-MYC and BCL6 oncogenes, and to constant region genes of the IG genes. LD-PCR with a newly available Taq polymerase for longer product synthesis successfully amplified fragments representing BCL3/C alpha junctional sequences for t(14;19); c-MYC/C mu, c-MYC/C gamma and c-MYC/C alpha for t(8;14); BCL6/C lambda for t(3;22); BCL6/C kappa for t(2;3); 5'-BCL6/C mu and 5'-BCL6/C gamma for t(3;14), respectively. The sizes of the amplified fragments were varied from 1.8 kb to 12 kb, which were specific to each material. Present study provides a useful tool for diagnosis and subsequent management of B-cell lymphoma/leukemia characterized with specific chromosomal translocation.

B-Cell Lymphoma 3 Protein↗
PubMed1997

Rearrangement of the BCL6 gene in B-cell lymphoid neoplasms.

We report here a large series of B-cell neoplasms with regard to rearrangement of the BCL6 gene on chromosome band 3q27. Southern blot analysis using probes from the major translocation cluster (MTC) region of the BCL6 revealed rearrangement in 32 of a total of 222 patients with various subtypes of B-cell neoplasm. In non-Hodgkin's lymphoma (NHL), rearrangements of the BCL6 gene were not closely associated with a specific histopathologic subtype but distributed in subcategories in the Working Formulation. A comparative study between NHL associated either with BCL2 or BCL6 rearrangement showed that advanced disease and bone marrow involvement were more frequent in BCL2(+) NHL. In contrast, extranodal involvement was more frequently observed in the BCL6(+) NHL. The survival curve of BCL6(+) NHL was characterized by a rapid decline followed by a plateau. Of the total of 32 BCL6(+) patients, 6 carried both BCL2 and BCL6 rearrangements, and showed clinicopathological properties of follicular lymphoma. This study suggests that BCL6 rearrangement is primarily associated with large cell lymphoma, and that BCL2(-)BCL6(+) NHL could potentially be curable with modern combination chemotherapy.

Bone Marrow↗
PubMed1997

[Transthoracic digital color Doppler assessment of the left anterior descending coronary artery and intramyocardial blood flow].

Noninvasive assessment of the distal left anterior descending coronary artery and intramyocardial blood flow were attempted in 50 consecutive patients (28 males and 22 females, mean age [+/-SD] 58 +/- 12 years) using a 7.5 MHz transducer (Doppler frequency: 5 MHz) and a SSA-380A ultrasound digital system with special optimal settings for the color Doppler examination. Modified apical acoustic windows were used to visualize the blood flow in the distal left anterior descending coronary artery and the intramyocardial artery. By selecting a sample volume (2 mm wide) on the color trace of these blood flows, Doppler spectral tracing of the distal left anterior descending coronary artery and intramyocardial blood flows could be recorded using pulsed-wave Doppler system. Blood flow in the distal left anterior descending coronary artery was detected in 43 (86%, Vmax = 22 +/- 8.7 cm/sec, Vmean = 16 +/- 5.1 cm/sec) of 50 patients, and intramyocardial blood flow in 40 (80%, Vmax = 26 +/- 11.0 cm/sec, Vmean = 19 +/- 8.5 cm/sec) of 50 patients. Distal left anterior descending coronary artery and the intramyocardial blood flows can be imaged by transthoracic digital color Doppler echocardiography in the clinical setting.

Coronary Circulation↗
PubMed1997

[Sudden onset of bronchospasm and persistent hypotension during spinal anesthesia in a patient on long-term psychotropic therapy].

We experienced perioperative management of a patient on long-term psychotropic therapy. The patient was a 65-year-old man who underwent TUR of the prostate under spinal anesthesia. Bronchospasm and persistent hypotension occurred immediately after the beginning of TUR. Aminophylline improved bronchospasm, but it was difficult to keep blood pressure with continuous infusion of norepinephrine or epinephrine. The patient recovered from anesthesia safely. We should pay attention to bronchospasm as well as hypotension in a patient on long-term psychotropic therapy during perioperative period.

Aminophylline↗
PubMed1997

[Measurement of plaque volume using three-dimensional intravascular ultrasound: in vitro study].

The usefulness of three-dimensional echocardiography using intravascular ultrasound (3D-IVUS) for the measurement of plaque volume was evaluated by comparing plaque volume derived from 3D-IVUS with that directly measured in 10 autopsied iliac or femoral plaque models (5-15 mm long). Using IVUS (3.5 F, 30 MHz), sequential cross-sectional images for three-dimensional datasets were acquired with a motorized catheter pullback device connected to the three-dimensional reconstruction system. Three-dimensional reconstruction was performed from the sum of the two-dimensional cross-sectional views. Plaque volumes were calculated using a summation of disks algorithm based on the reconstructed multiple short-axis cross-sections from the three-dimensional data. Three-dimensional IVUS demonstrated a good correlation with direct measurement of plaque volume (y = 0.71x + 0.001, r = 0.80, SEE = 0.003 ml), so is useful for the measurement of plaque volumes in the experimental models.

Arteriosclerosis↗
PubMed1997

[Comparative studies of airway deposition of 99mTc-DTPA aerosol particles among 4 different nebulizers by pulmonary scintillation method].

The inhalation therapy is one of the important treatment of bronchial asthma. The effectiveness of the therapy, however, is different depending on the size of particles produced by each inhalation equipment. Therefore, we have tried to clarify the relationship between the size of inhaled particles and the deposition rate in the lung by using different types of equipment. Four different equipments, Nishou, Pari-Boy, Pari-Master and Atom Soniclizer 905 were used. 99mTc-DTPA was dissolved in physiological saline and was inhaled for evaluation of "deposition" rate in the lung. The deposition rates by Nishou, Pari-Boy, Pari-Master and Atom Soniclizer 905 were 10.4 +/- 5.8%, 27.5 +/- 14.5%, 28.5 +/- 6.5%, and 31.1 +/- 6.8%, respectively. Most of 99mTc-DTPA inhaled was observed in oral cavity. The deposition in the lung by Nishou was significantly reduced compared to other three nebulizers. Those three were evaluated as appropriate equipments for the treatment. The average size of particles in an airsol by those three equipments was less than 5 microns. The study suggests that the size of "particles" in an airsol is very important factor for the inhalation therapy.

Adult↗
PubMed1997

[Phasic coronary flow velocity pattern characteristics of myocardial bridging: a Doppler guide wire study].

The phasic coronary flow velocity pattern of myocardial bridging was analyzed using a 0.014 inch, 15 MHz Doppler guide wire. Coronary flow velocities and coronary flow reserve at rest and maximum hyperemic time were measured in nine patients with myocardial bridging and 11 normal subjects. Systolic flow reversal followed by prominent early diastolic peak velocity patterns was observed in seven patients (78%) in vessels with myocardial bridging. The systolic time velocity integral was significantly smaller in patients with myocardial bridging than in normal subjects (-1.3 +/- 1.5 vs 4.0 +/- 1.2 cm, p < 0.01), but the diastolic time velocity integral was not significantly different. However, the time velocity integral throughout a cardiac cycle was significantly different between the two groups (12.8 +/- 2.2 vs 18.8 +/- 6.3 cm, p < 0.05). Maximum hyperemic time-averaged peak velocity was significantly lower in patients with myocardial bridging than in normal subjects (40.7 +/- 10.3 vs 57.6 +/- 15.5 cm/sec, p < 0.01), but there was no significant difference in coronary flow reserve between the two groups (2.9 +/- 0.6 vs 3.3 +/- 0.4). Systolic flow reversal followed by prominent early diastolic peak velocity patterns was observed in patients with myocardial bridging. The systolic time velocity integral was significantly smaller in patients with myocardial bridging, so the time velocity integral throughout a cardiac cycle was significantly smaller. There was no significant correlation between coronary flow reserve and ratio of stenosis, and coronary flow reserve was maintained.

Adult↗