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Biomedical subjects

K Maeda

Publications and source records attributed to K Maeda.

At least 1,225 records · Page 68Linked to original sources
PubMed1987

Crystallographic study of endogenous alpha-amylase inhibitor from wheat.

Endogenous alpha-amylase inhibitor from wheat has been crystallized by a microdialysis method. There are two forms of monoclinic crystal in a microdialysis cell with a space group of P2(1). The unit cell dimensions are a = 43.5 A, b = 64.8 A, c = 32.2 A, beta = 113 degrees for the rod-like crystal, and a = 42.5 A, b = 65.2 A, c = 32.2 A, beta = 112 degrees for the plate-like crystal. The former is suitable for structure analysis because it gives the sharp diffraction beyond 2.0 A resolution, and the latter tends to form a twin crystal. A heavy-atom derivative has been successfully prepared with the heavy-atom reagent K2PtCl4, and structure analysis is in progress.

Crystallography↗
PubMed1987

Development of MoAb HMSA-2 for melanosomes of human melanoma and its application to immunohistopathologic diagnosis of neoplastic melanocytes.

To characterize the biologic and molecular nature of melanosomal proteins, we recently developed two mouse monoclonal antibodies (MoAbs), human melanosome-associated antigen (HMSA)-1 and HMSA-2, for melanosomes isolated from human malignant melanoma. This study describes the methods of development for MoAb HMSA-2 and the specificity and distribution of antigen(s) reactive with it in normal and pathological tissues. Characteristically, MoAb HMSA-2 was found to detect neoplastic melanocytes on formalin-fixed and paraffin-processed specimens. The reaction patterns for benign and malignant melanocytic tumors were different, i.e., homogeneous reactivity in the dermal cells of common melanocytic nevi but heterogeneous reactivity in the same type of cells in malignant melanoma. MoAb HMSA-2 reacted positively with the epidermal melanocytes in the lesions of dysplastic melanocytic nevi, but not with those of common melanocytic nevi. Reaction products with MoAb HMSA-2 were localized in the cytoplasm. MoAb HMSA-2 did not react with normal melanocytes even on frozen sections. Benign and malignant epithelial and soft tissue tumors of the skin were usually negatively stained with MoAb HMSA-2. Findings indicate that MoAb HMSA-2 is a unique MoAb which identifies neoplastic melanocytes and which can be useful in differentiating each type of melanocytic tumor.

Antibodies, Monoclonal↗
PubMed1987

Normal development of the spinal cord in neonates and infants seen on ultrasonography.

The normal development of the spinal cord from the fetal period to infancy was studied by ultrasonography (US) with a 7.5 MHz transducer. Longitudinal and transverse sections of the spinal cord were clearly observed. The sagittal and transverse diameters of the spinal cord increased with age. In order to evaluate disorders of the spinal cord precisely, it is necessary to clarify the normal features as well as the normal development of the spinal canal and cord, and the surrounding structures. US with such a high frequency transducer will be the most suitable for this purpose.

Gestational Age↗
PubMed1987

Two cases of rectal carcinoma associating aorto-iliac occlusive disease.

Two cases of rectal carcinoma associating aorto-iliac occlusive disease are presented. These two cases had complete obstruction of the affected vessels, but many collateral pathways from the aorta to the legs had developed, mainly through the superior rectal artery or parietal vessels. Changes in blood flow to the legs, following the radical operation for rectal carcinoma, were examined by both preoperative angiography and perioperative Doppler flow meter. Vascular reconstruction was carried out in one case prior to resection of the rectum, in order to prevent the ischemic legs from becoming worse, or necrotic. The indications for supportive vascular surgery in the case of rectal carcinoma with aorto-iliac occlusive disease are discussed herein.

Adenocarcinoma↗
PubMed1987

A possible serum marker for rejection after small intestine transplantation.

Frequent histologic evaluation of mucosal biopsies remains the most reliable method of monitoring and diagnosing rejection after small intestine transplantation, but lengthy processing time can result in delay in diagnosis. Unfortunately, a serum marker for monitoring small intestine transplantation rejection has not been identified. Hexosaminidase, a lysosomal acid hydrolase, has been shown to increase in serum in association with intestinal ischemia, a finding also associated with acute rejection after small intestine transplantation. We measured N-acetyl hexosaminidase levels after transplantation in three groups of five rats each as follows: Group I, Lewis strain small intestine to Lewis recipients; Group II, Wistar small intestine to Lewis recipients; and Group III, Wistar small intestine to Lewis recipients treated with 25 mg/kg per day of cyclosporine. Serum N-acetyl hexosaminidase levels and mucosal biopsies were obtained on days 0, 2, 4, 6, 8, 10, 12, 14, and 21. Rats in Groups I and III survived without gross evidence of rejection. Three rats in Group II died between 8 and 10 days, and serum N-acetyl hexosaminidase levels increased 24 to 48 hours before death. In the remaining Group II rats, the N-acetyl hexosaminidase levels were significantly higher on days 10, 12, and 14 after transplantation (p less than 0.05). In two of five rats, the histologic changes of rejection occurred later than the increase in N-acetyl hexosaminidase levels. Because measurement of N-acetyl hexosaminidase levels is a rapid and simple serum assay, it may be useful for monitoring rejection after small intestine transplantation.

Animals↗
PubMed1987

Expression of the T-cell receptor gamma-chain gene products on the surface of peripheral T cells and T-cell blasts generated by allogeneic mixed lymphocyte reaction.

The gamma-chain genes of the T-cell receptors form a family of related genes that are specifically expressed and somatically rearranged in T cells. Using poly- and monoclonal anti-gamma antibodies, we studied the cell-surface expression of the gamma-chain gene products in mouse peripheral T cells as well as in the T-cell blasts generated by allogeneic mixed lymphocyte reactions. The gamma chains are expressed in the Lyt2-,L3T4- subsets of these T-cell populations as disulfide-linked heterodimers. Whereas the electrophoretic mobility and the N-glycosylation of the spleen and lymph-node gamma chains are indistinguishable from those of the reported thymocyte gamma chain, a minor fraction of the T blasts generated by allogeneic stimulation of B10 lymph-node T cells with B10.BR spleen cells seems to express gamma chains with distinct properties. This suggests that the mixed lymphocyte culture conditions exert a selective effect on the expression of gamma chains among peripheral T-cell populations.

Animals↗
PubMed1987

Dysplastic melanocytic nevus. Electron-microscopic observation as a diagnostic tool.

Dysplastic melanocytic nevi (DMN) are distinctive cutaneous nevomelanocytic lesions that possess unique clinical and histopathological features. In our previous study, we showed that the fine structure of melanosomes in epidermal melanocytes of DMN are abnormal and reveal deranged melanogenesis. This study is an extension of our previous study and clarifies the fine structure of melanosomes in both epidermal melanocytes and keratinocytes with observations in an additional 10 cases of DMN with and without a marked mesenchymal response. We found that a poor mesenchymal response does not exclude fine structural abnormality of melanosomes in DMN; that abnormal melanosomes are manifested by a spherical shape with either fine granules or incompletely developed lamellae and/or both; that melanization occurs unevenly on the spherical granular and/or incompletely on the lamellar matrices; and that these abnormal melanosomes are transferred to keratinocytes before being completely melanized, and they reveal marked degradation. We suggest that the fine structural characterization of abnormal melanosomes is a new adjunct for histopathological diagnosis of DMN.

Dysplastic Nevus Syndrome↗
PubMed1987

A T-shaped musculomucosal buccal flap method for cleft palate surgery.

The primary aim of cleft palate surgery is not only to close the cleft palate but to push back the palate by repositioning the levator muscle to ensure that normal speech is obtained. Although the pushback operation using a mucoperiosteal flap is a readily effective method for velopharyngeal closure, postoperative fistula sometimes occurs, especially when the cleft palate is wide. Furthermore, postoperative maxillary deformity, possibly due to elevating the mucoperiosteal palatal flap, is extremely troublesome. For the purpose of pushing back the nasal mucosa, we applied the Kaplan buccal flap method, which is also applicable for reestablishing the levator muscle sling. The other buccal flap is covered on the hinged flap of the pared cleft margins. This results in far less disturbance of maxillary growth. We call it the T-shaped buccal flap method, and we have applied it in over 30 patients with various cleft palates and have obtained satisfactory results.

Cheek↗
PubMed1987

Development of MoAb HMSA-3 and HMSA-4 against human melanoma melanosomes and their reactivities on formalin-fixed melanoma tissues.

To elucidate the nature of melanosomal protein in normal and malignant melanocytes, two mouse monoclonal antibodies (MoAbs), designated MoAb HMSA-3 and MoAb HMSA-4, were developed by the solubilized melanosomes of human malignant melanoma. The specificity of the two MoAbs was characterized immunohistochemically by comparison with that of MoAb HMSA-2 in various forms of melanoma tissues. MoAb HMSA-3 and MoAb HMSA-4 were IgM, k subclass while MoAb HMSA-2 was IgG1, k subclass. The three MoAbs possessed many similarities; (a) positive reactivity in formalin-fixed and paraffin-processed specimens, (b) identification of cytoplasmic antigen(s) in melanoma cells, (c) negative reactivity with normal epidermal melanocytes on paraffin-sections, and (d) intense reaction with amelanotic melanoma cells, particularly in superficial spreading and acral lentiginous melanoma and in metastatic lymph nodes. The three MoAbs, however, identified the different cells on the same serial sections, suggesting that the three may recognize the different epitopes. Thus in 32 cases of primary and metastatic melanomas examined, one of the three MoAbs always showed a positive reactivity, though the other two were negatively or weakly reacted. Our study indicated that the melanosomal protein may provide a unique source to develop MoAbs which identify malignant melanocytes on routine paraffin sections.

Animals↗
PubMed1987

Dual surface makers and HTLV-I proviral DNA in a cutaneous tumour nodule in a case of adult T cell leukaemia/lymphoma.

The phenotypic and morphological profiles of atypical cells in a case of adult T cell leukaemia/lymphoma were studied using a panel of monoclonal antibodies and electron microscopy. Retroviral sequence restriction analysis showed the presence of human T cell leukaemia/lymphoma virus type I (HTLV-I) in the skin lesion. Our case showed several unique features in the clinical, haematological, histopathological and immunohistochemical findings. An erythematous plaque and tumour nodules in the skin were found without any abnormal lymphocytes such as flower cells in the peripheral blood and bone marrow HTLV-I proviral DNA was detected in the skin tumour cells but not in the peripheral blood lymphocytes, and in the tumour nodule, atypical cells showed a distinct difference in morphology between cerebriform cells in the upper dermis and large lymphoid cells in the lower dermis. The cerebriform cells had, immunohistochemically, a T helper/inducer (Th/i) phenotype whereas the large lymphoblastoid cells possessed both the Th/i and T suppressor/cytotoxic (Ts/c) phenotypes. Ki-I antigen was detected in the large lymphoblastoid cells, but not in the cerebriform cells.

Adult↗
PubMed1987

Abnormal growth hormone release following luteinizing hormone releasing hormone in anorexia nervosa.

We studied the luteinizing hormone (LH), follicle stimulating hormone (FSH) and growth hormone (GH) secretion following an i.v. injection of 0.1 mg of luteinizing hormone releasing hormone (LHRH) in patients with anorexia nervosa, who showed the GH secretion after thyrotropin releasing hormone (TRH). Five out of 11 patients had an elevated plasma GH level in a fasting state. The administration of LHRH resulted in a significant increase in the plasma GH concentrations in 3 of the 11 patients. Three other patients also showed an elevation of the plasma GH concentration to 7.0, 18.4 and 29.6 ng/ml, which were 212, 175 and 191% of the preinjection levels, respectively. There is a positive correlation between the basal and peak plasma GH levels after LHRH. These increases, however, were related to neither the plasma gonadotropin responses to LHRH nor the plasma GH responses to TRH. The basal levels of plasma LH were reduced in 8 patients and normal responses to LHRH were observed in only one patient. Although plasma FSH was undetectable in 5 patients, the FSH response to LHRH appeared normal in 9 patients. These results indicate that an elevation of the plasma GH level after LHRH is not confined to patients with a GH secreting pituitary tumor but observed in subjects with anorexia nervosa and further suggest that the GH responsiveness to non-specific hypothalamic releasing hormones may be due to the impaired hypothalamic control in anorexia nervosa.

Adolescent↗