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Biomedical subjects

H Matsuba

Publications and source records attributed to H Matsuba.

15 recordsLinked to original sources
PubMed2001

MR imaging of primary leiomyosarcoma of the thyroid gland.

Primary leiomyosarcoma of the thyroid gland is extremely rare and radiological information on this tumor is scant. We presented radiological findings on primary thyroid leiomyosarcoma in a 66-year-old woman in which anaplastic carcinoma was suspected based on clinical and cytological features and discussed the radiological clues to distinguish between the two diseases. Ultrasonography showed an ill-defined hypoechoic mass without halo in the left lobe and the isthmus of the thyroid gland. Computed tomography depicted a low-density mass with calcification and necrosis, which invaded the thyroid cartilage. No lymphadenopathy was seen. The tumor was demonstrated as an isointense mass on T1-weighted MR images and a mass of intermediate signal on T2-weighted images. The tumor showed a fair enhancement on gadolinium-enhanced T1-weighted images. Although the radiological picture was nonspecific, primary thyroid leiomyosarcoma appeared less invasive and far less frequent in developing nodal metastasis than anaplastic carcinoma in light of the literature.

Aged↗
PubMed2001

Tracheal invasion by thyroid carcinoma: prediction using MR imaging.

OBJECTIVE: The purpose of this study was to evaluate the accuracy of MR imaging in predicting tracheal invasion by thyroid carcinomas and to determine MR imaging criteria for diagnosing tracheal invasion. MATERIALS AND METHODS: MR imaging was performed on the normal trachea of one cadaver and 30 healthy subjects as a standard of reference. Then, MR imaging findings in 67 patients with thyroid carcinoma were reviewed and correlated with surgical and pathologic findings. A logistic regression model was used to determine which MR imaging features were significant for predicting tracheal invasion. RESULTS: Twenty-three (34%) of the 67 patients had tracheal invasion. Logistic regression model analysis revealed that significant MR characteristics for determining tracheal invasion included soft-tissue signal in the tracheal cartilage (p < 0.001), intraluminal mass (p < 0.001), and degree of tumor circumference around the trachea (p = 0.001). The highest accuracy (90%) for determining tracheal invasion was achieved using a combination of findings. A case was considered positive for tracheal invasion if there was soft-tissue signal in the cartilage, an intraluminal mass, or a tumor that abutted a circumference of the trachea of 180 degrees or greater. Using these factors resulted in seven false-positive diagnoses because soft-tissue signal in the cartilage was sometimes seen in healthy trachea. Although intraluminal mass invariably reflected deep tracheal invasion, soft-tissue signal in the cartilage rarely indicated actual cartilage invasion but rather indicated tumor extension between the cartilaginous rings. CONCLUSION: Tracheal invasion by thyroid carcinomas can be accurately diagnosed with MR imaging, and using a combination of criteria is the most accurate method of predicting this phenomenon.

Adult↗
PubMed1994

Characterization of a 60-kilodalton substrate of the insulin receptor kinase.

A 60-kDa tyrosine-phosphorylated protein has been observed after insulin treatment of cells in immunoprecipitations of the GTPase-activating protein of Ras (called GAP) as well as the phosphatidylinositol 3-kinase. In the present studies, these two 60-kDa proteins have been shown to differ by limited proteolytic digestions as well as by immunoprecipitation with a monoclonal antibody. This monoclonal antibody was also utilized to show that the 60-kDa GAP-associated protein was rapidly phosphorylated in intact cells after insulin stimulation and to associate with GAP only after insulin treatment of the cells. In addition, the 60-kDa protein was found to be phosphorylated in vitro by the insulin receptor. Finally, the 60-kDa protein immunoprecipitated by this antibody was found not to react with a polyclonal antibody directed against a 62-kDa tyrosine-phosphorylated GAP-associated protein previously observed in src-transformed cells. These studies indicate that insulin stimulates the tyrosine phosphorylation of at least two distinct 60-kDa proteins, one that becomes associated with GAP and appears to be a direct substrate of the insulin receptor kinase and another that associates with the phosphatidylinositol 3-kinase.

Animals↗
PubMed1994

Enzyme-linked immunosorbent assay method for human autophosphorylated insulin receptor. Applicability to insulin-resistant states.

The insulin receptors from erythrocytes of 50 patients with non-insulin-dependent diabetes mellitus were tested for their ability to autophosphorylate. The assay was performed by a new enzyme-linked immunosorbent assay system that used monoclonal anti-insulin receptor antibodies absorbed to microtiter plates as a first antibody and polyclonal antiphosphotyrosine antibody as a labeled second antibody. By this assay, 3 patients were identified with defects in their insulin receptor kinase, although their defects appeared heterogeneous. Patient 1 had 85% less maximal autophosphorylation with a normal ED50 (1.6 x 10(-9) M insulin). Patient 2, who had polycystic ovary disease, had a 49.2% decrease in maximal autophosphorylation of insulin receptors, and the ED50 was shifted to the right (5.6 x 10(-8) M). Patient 3 with acanthosis nigricans had a normal maximal autophosphorylation, but the ED50 shifted to the right (2.9 x 10(-8) M). The mechanisms for the diversity detected in this assay is not known, but this technique has sufficient specificity and sensitivity to be used to screen for insulin-resistant patients who have a lack of kinase activity.

Adult↗
PubMed1992

Insulin-dependent formation of a complex containing an 85-kDa subunit of phosphatidylinositol 3-kinase and tyrosine-phosphorylated insulin receptor substrate 1.

Monoclonal antibodies raised against the 85-kDa subunit (p85) of bovine phosphatidylinositol (PI) 3-kinase were found to recognize uncomplexed p85 or p85 in the active PI 3-kinase. Immunoprecipitation studies of Chinese hamster ovary cells, which overexpress the human insulin receptor when treated with insulin, showed increased amounts of p85 and PI 3-kinase activity immunoprecipitable with monoclonal anti-p85 antibody and no increase in the tyrosine phosphorylation of p85. Insulin also induced an association of p85 with the tyrosine-phosphorylated insulin receptor substrate 1 (IRS-1) and other phosphorylated proteins ranging in size from 100 to 170 kDa but not with the activated insulin receptor. In vitro reconstitution studies were used to show p85 in the active PI 3-kinase associated with the tyrosine-phosphorylated IRS-1 but not with the activated insulin receptor. Competition studies using synthetic phosphopeptides corresponding to potential tyrosine phosphorylation sites of IRS-1 revealed that phosphopeptides containing YMXM motifs inhibited this association with different potencies, whereas nonphosphorylated analogues and a phosphopeptide containing the EYYE motif had no effect. Src homology region 2 domains of p85 expressed as glutathione S-transferase fusion proteins also bound to tyrosine-phosphorylated IRS-1. These results suggest that insulin causes the association of PI 3-kinase with IRS-1 via phosphorylated YMXM motifs of IRS-1 and Src homology region 2 domains of p85.

Amino Acid Sequence↗
PubMed1991

Methyl prednisolone in double-lumen gel-saline submuscular mammary prostheses: a double-blind, prospective, controlled clinical trial.

At the time of immediate breast reconstruction with submuscular implants, 76 consecutive patients (89 breasts) were randomized into two groups. One received a gel-saline, double-lumen implant with 40 cc of saline added to the outer lumen, while the other received the same implant plus 40 cc of saline and 16 mg methyl prednisolone (40 mg%). Patients were followed for a minimum of 3 years. The groups, which were matched for patient age and implant size, were evaluated at 3, 12, 24, and 36 months for capsular contracture, steroid atrophy, and other complications. With completion of the double-blind study, the patients with submuscular gel-saline implants with only saline added had an overall capsular contracture rate of 38 percent at 3 months, 38 percent at 12 months, and 44 percent at 24 and 36 months. Those with methyl prednisolone had an overall capsular contracture rate of 14 percent at 3 months, and this remained unchanged through the end of the study. The rates of all other complications were comparable. Methyl prednisolone in a dose of 16 mg in 40 cc saline (concentration 40 mg%), when used in the outer lumen of a double-lumen gel-saline implant in a submuscular pocket, is both safe and efficacious in reducing the risk of capsular contracture for a minimum of 3 years in patients undergoing immediate breast reconstruction with submuscular mammary implants.

Adult↗
PubMed1989

Variations in immunocytochemical localization of cathepsin B and thyroxine in follicular cells of the rat thyroid gland and plasma TSH concentrations over 24 hours.

Immunocytochemical localization of cathepsin B and thyroxine (T4) in follicular cells of the rat thyroid gland and plasma concentrations of thyroid stimulating hormone (TSH) were examined at six evenly spaced times over 24 h. By light- and electron microscopy, immunodeposits for cathepsin B were localized in cytoplasmic granules of various sizes, whereas those for T4 were detected mainly in larger granules of the cells and in the colloid lumen. The size and location of cytoplasmic granules showing immunoreactivity for cathepsin B and T4 in the cells varied over 24 h, corresponding to a change in plasma TSH concentrations. These immunopositive large granules appeared in the apical cytoplasm at 12.00 h, when the level of TSH was highest. At 20.00 h when the level of TSH was lowest, T4-positive granules almost disappeared, and cathepsin B-positive small granules were abundantly seen in the basal region. From 00.00 h to 08.00 h, these positive granules changed in the same manner as those seen from 12.00 h to 20.00 h, associated with an increase in plasma TSH levels. These results suggest that newly formed colloid droplets migrate from the apical to the basal regions. Cathepsin B may play a role not only in the degradation of thyroglobulin but in the maturation of thyroid hormones during the migration of the granules.

Animals↗
PubMed1989

Immunocytochemical localization of prorenin, renin, and cathepsins B, H, and L in juxtaglomerular cells of rat kidney.

To examine the correlation of localization of prorenin, renin, and cathepsins B, H, and L, immunocytochemistry was applied to rat renal tissue, using a sequence-specific anti-body (anti-prorenin) that recognizes the COOH terminus of the rat renin prosegment. In serial semi-thin sections, immunodeposits for prorenin, renin, and cathepsins B, H, and L were localized in the same juxtaglomerular (JG) cells. Immunodeposits for renin were detected throughout the cytoplasm of the cells, whereas those for prorenin were detected in the perinuclear region. Immunoreactivity for cathepsin B was stronger than that for cathepsins H and L. By electron microscopy, prorenin was localized in small (immature) granules but not in large mature granules, whereas renin was localized mainly in mature granules. In serial thin sections, prorenin, renin, and cathepsin B were colocalized in the same immature granules containing heterogeneously dense material (intermediate granules). By double immunostaining, co-localization of renin with cathepsins B, H, or L was demonstrated in mature granules. The results suggest the possibility that processing of prorenin to renin occurs in immature granules of rat JG cells, and cathepsin B detected in JG cells may be a major candidate for the maturation of renin.

Animals↗
PubMed1989

An immunocytochemical study on co-localization of cathepsin B and atrial natriuretic peptides in secretory granules of atrial myoendocrine cells of rat heart.

To examine localization of cathepsin B, a representative lysosomal cysteine protease, in atrial myoendocrine cells of the rat heart, immunohistochemistry at the light and electron microscopic level was applied to the atrial tissue, using a monospecific antibody for rat liver cathepsin B. In serial semi-thin sections, immunoreactivity for cathepsin B and atrial natriuretic peptides (ANP) was detected in the para-nuclear region of atrial myoendocrine cells. Several large granules and many fine granules in the region of the cells were positively stained by the cathepsin B antibody. Gold particles indicating cathepsin B antigenicity labeled secretory granules in the cells, which were also labeled by those indicating ANP, using thin sections of the Lowicryl K4M-embedded material. Moreover, some granules labeled densely by immunogold particles for cathepsin B seemed to be lysosomes. By double immunostaining using thin sections of the Epon-embedded material, gold particles indicating cathepsin B and ANP antigenicities were co-localized in secretory granules of the cells. By enzyme assay, activity of cathepsin B was three times higher in atrial tissue than ventricular tissue. The results suggest that co-localization of cathepsin B and ANP in secretory granules is compatible with the possibility that cathepsin B participates in the maturation process of ANP.

Animals↗
PubMed1989

Immunocytochemical localization of cathepsins B, H, L, and T4 in follicular cells of rat thyroid gland.

To localize cathepsins B, H, and L in follicular cells of rat thyroid gland, we applied immunocytochemistry to the thyroid tissue using their respective monospecific antibodies. On serial semi-thin sections, cathepsins B, H, and L were localized in granules of various sizes located throughout the cytoplasm, whereas T4 was detected in larger granules located in the apical and supranuclear regions. By electron microscopy, cathepsins B, H, and L were localized in large less-dense granules (so-called colloid droplets) and in dense bodies of various sizes, whereas T4 was localized more intensely in large less-dense granules than in smaller dense bodies. By double immunostaining using an immunogold method, cathepsins H and B or L were co-localized in the same cytoplasmic granules. Moreover, immunoblotting demonstrated that proteins similar to cathepsins B, H, and L in the liver are present in the thyroid gland. These results suggest that cathepsins B, H, and L participate not only in degradation of thyroglobulin but in maturation of thyroid hormones, although it remains unknown whether all of them participate in the maturation process.

Animals↗
PubMed1989

The medial periareolar approach to submuscular augmentation mammaplasty under local anesthesia.

The medial approach to submuscular augmentation mammaplasty under local anesthesia begins with a medial periareolar incision around one-half or more of the areola. A subcutaneous tunnel is made toward the medial breast border, avoiding mammary ducts and sensory nerves to the nipple. The breast is reflected laterally, exposing a patch of pectoralis major muscle. A submuscular pocket is then created beneath portions of the pectoralis major, rectus abdominis, external oblique abdominis, and serratus anterior muscles, after which the implant is inserted and the muscle, dermis, and skin are closed sequentially. The periareolar incision allows for favorable scars without compromising the access or exposure necessary for accurate implant placement. Complete muscle coverage of the implant should contribute to a lower rate of capsular contracture. With a medial submuscular approach, nipple sensation is rarely altered, and revisions, if necessary, can be done through the same incision, still under local anesthesia, for increased safety, economy, and convenience. The medial approach to breast augmentation is a highly versatile, safe, and consistent method of achieving excellent results in breast augmentation in terms of scar, symmetry, and softness.

Adult↗
PubMed1988

Correlation of 24-hour fluctuations in renin granules of juxtaglomerular cells and in renin and angiotensinogen in blood plasma of the rat.

Subcellular structures of juxtaglomerular (JG) cells in the rat kidney were morphometrically examined at six evenly spaced times over 24 h. Plasma renin activities and angiotensinogen concentrations were also measured at these times. The cell volumes were larger at 20.00 h and 04.00 h than at 00.00 h, whereas the nuclear volumes peaked at 20.00 h and 08.00 h, decreasing at 00.00 h and 16.00 h. The volume and surface densities of renin granules and their individual volumes and surface areas peaked at 16.00 h and 00.00 h, decreasing at 20.00 h and 08.00 h, whereas their numerical densities peaked at 20.00 h, decreasing at 12.00 h. The surface densities of the rough endoplasmic reticulum (rER) peaked at 20.00 h, decreasing at other times, except at 08.00 h, when rER volume and surface density were relatively high. The plasma renin activity was maximal at 20.00 h, whereas it was minimal at 08.00 h. The variation in plasma angiotensinogen concentrations was inversely correlated with that in plasma renin activities. These results suggest that JG cells actively synthesize and release renin during the dark period, especially at 20.00 h, whereas during the light period they gradually synthesize renin and produce the granules, most of which may be stored in the cells during this period.

Angiotensinogen↗
PubMed1988

Immunocytochemical localization of cathepsins B, H, and their endogenous inhibitor, cystatin beta, in islet endocrine cells of rat pancreas.

To determine the characteristics of lysosomes in rat islet endocrine cells, we examined the precise localization of cathepsins B, H, and L and their specific inhibitors, cystatins alpha and beta, using immunocytochemical techniques. By use of serial semi-thin sections, we detected immunoreactivity for cathepsin B in insulin-, glucagon-, somatostatin-, and pancreatic polypeptide-positive (PP) cells. Strong immunoreactivity for cathepsin H was seen in A-cells and weak immunoreactivity in PP cells, but none in others. Immunodeposits for cystatin beta were demonstrated in B-cells. Brief dipping of thin sections in 1% sodium methoxide before the following immunocytochemical reaction enhanced specific deposits of immunogold particles on the target organelles. Use of a double-immunostaining technique showed co-localization of insulin with cystatin beta in many secretory granules. This suggests that cystatin beta may regulate converting enzymes participating in the maturation process of insulin. By use of an immunogold technique, heterogeneous localization of cathepsins B and H in lysosomes was also found among islet cells at the light microscopic level. This may be due to the difference in peptides degraded in lysosomes among the cells.

Animals↗