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Biomedical subjects

M Sasaki

Publications and source records attributed to M Sasaki.

At least 343 records · Page 19Linked to original sources
PubMed1999

Idiopathic cortical myoclonus restricted to the lower limbs: correlation between MEPs and 99mTc-ECD single photon emission computed tomography activation study.

We report a 63-year-old woman with cortical reflex myoclonus restricted to the bilateral lower limbs. Somatosensory evoked cortical potentials to posterior tibial nerve stimulation were enlarged with C-responses. Jerk-locked back averaging of the EEG identified a cortical spike related to myoclonic jerks. Motor evoked potentials recorded from the abductor hallucis muscle showed an exaggerated late response. These findings suggest hyperexcitability of the sensorimotor cortex. 99mTc-ECD single photon emission computed tomography (SPECT) after stimulation of the posterior tibial nerve showed increased perfusion in the contralateral peri-Rolandic area which corresponded to the hyperexcitable region. A SPECT activation study as well as MEPs therefore can be employed to determine the hyperexcitable region in cortical myoclonus.

Brain↗
PubMed1999

Opsonic complement component C3 in the solitary ascidian, Halocynthia roretzi.

The recent identification of two mannose-binding lectin-associated serine protease clones from Halocynthia roretzi, an ascidian, suggested the presence of a complement system in urochordates. To elucidate the structure and function of this possibly primitive complement system, we have isolated cDNA clones for ascidian C3 (AsC3) and purified AsC3 protein from body fluid. The deduced primary structure of AsC3 shows overall similarity to mammalian C3, including a typical thioester site with the His residue required for nucleophilic activation of the thioester. AsC3 has a two-subunit chain structure, and the alpha-chain is cleaved at a specific site near to the N terminus upon activation. Ascidian body fluid contains an opsonic activity which enhances phagocytosis of yeast by ascidian blood cells, and Ab against AsC3 inhibits this opsonic activity. These results indicate that the complement system played a pivotal role in innate immunity by enhancing phagocytosis before the emergence of the vertebrates and well ahead of the establishment of adaptive immunity, which is believed to have occurred at about the time of the appearance of cartilaginous fish.

Amino Acid Sequence↗
PubMed1999

Expression of MUC1 and MUC2 mucin core proteins and their messenger RNA in gall bladder carcinoma: an immunohistochemical and in situ hybridization study.

Expression of mucin core protein MUC1 and MUC2 was examined at the protein and mRNA level in 55 cases of carcinoma and 20 of dysplasia, and in 15 non-dysplastic epithelia of the gall bladder. In non-dysplastic epithelium, MUC1 protein was not expressed, while in dysplasia, MUC1 was focally expressed in ten cases, particularly in those associated with carcinoma. In carcinoma, MUC1 was expressed heterogeneously, and the frequency and extent of MUC1 expression increased with histological dedifferentiation. MUC1 was found on the apical cell surface and also in the cytoplasm in well- and moderately-differentiated carcinoma, and on the cell border in poorly-differentiated cases. In infiltrative regions, MUC1 expression was more predominant and MUC1 frequently leaked outside the foci of carcinoma. By contrast, MUC2 was focally expressed in non-dysplastic as well as in dysplastic epithelia and more frequently in well-differentiated adenocarcinoma. MUC2-positive cells resembled goblet cells, whether in non-dysplastic epithelium, dysplasia or carcinoma. Cell proliferative activity was higher in MUC1-positive than in MUC1-negative carcinoma cells. Distributions of MUC1 and MUC2 mRNA signals and of MUC1 and MUC2 proteins were similar in carcinoma and dysplasia. These results suggest that MUC1 expression by gall bladder carcinoma may reflect histological dedifferentiation, increased proliferative activity, and invasiveness, while MUC2 expression is related to lower proliferative activity and reflects some differentiation towards goblet cells; and that MUC1 expression in gall bladder dysplasia reflects malignant transformation.

Adenocarcinoma↗
PubMed1999

Aberrant expression of stem cell factor on biliary epithelial cells and peribiliary infiltration of c-kit-expressing mast cells in hepatolithiasis and primary sclerosing cholangitis: a possible contribution to bile duct fibrosis.

Hepatolithiasis and primary sclerosing cholangitis (PSC) are intractable chronic biliary diseases. In hepatolithiasis, bilirubin-calcium stones are packed in multiple irregularly dilated intrahepatic bile ducts. In PSC, small bilirubin-calcium stones develop terminally. The progressive periductal fibrosis with dilated and stenotic bile ducts in these two diseases may play a role in their incurability. This immunohistochemical study has investigated the expression of some factors that might be involved in fibrogenesis in hepatolithiasis and PSC. Many mast cells positive for c-kit were found in the periductal and ductal fibrosis around the intrahepatic large bile ducts and also around the proliferative peribiliary glands. These mast cells also expressed basic fibroblast growth factor and/or tumour necrosis factor-alpha, which are known as fibrogenetic factors. It was of interest that the aberrant expression of stem cell factor (SCF), a ligand of c-kit, was demonstrated on biliary epithelia of the dilated and stenotic bile ducts showing periductal fibrosis and inflammation and also of the proliferated peribiliary glands in hepatolithiasis and PSC, while no such expression was seen in non-affected bile ducts in hepatolithiasis or in the bile ducts in normal livers. Some of the infiltrating mononuclear cells around the SCF-expressing bile ducts were also positive for SCF. It seems likely that aberrantly expressed SCF on biliary epithelial cells accumulates and stimulates mast cells via the c-kit receptor and that these up-regulated mast cells induce progressive periductal and portal fibrosis by displaying fibrogenetic factors in hepatolithiasis and PSC.

Bile Ducts, Intrahepatic↗
PubMed1999

Cytopathological observations in a 27-year-old female patient with endometrioid adenocarcinoma arising in the lower uterine segment of the uterus.

The determination of the malignancy of an endometrioid adenocarcinoma arising in the lower uterine segment (LUS) is difficult because of the high degree of differentiation of adenocarcinoma. The cytopathological and immunohistochemical features of endometrioid adenocarcinoma arising in the LUS of a young adult female are presented. The preoperative cytopathological examination of a 27-yr-old female could not enable an accurate diagnosis of malignancy. Hysterectomy specimens revealed the presence of an endometrioid-type adenocarcinoma with minimal atypia and myometrial invasion, which was located in the LUS. This tumor was consistent with a histological diagnosis of endometrioid minimal-deviation adenocarcinoma (MDA). Immunohistochemically, the tumor's glands were p53-, proliferating cell nuclear antigen-, and carcinoembryonic antigen-positive, and estrogen receptor-, progesterone receptor-,and vimentin-negative. The cytological and surgical specimens showed a remarkable association of squamous metaplasia. Although cytopathological difficulties in determining malignancy of MDA endometrioid adenocarcinoma arising in the LUS are well-known, the following features worth noting include: 1) squamous metaplasia on cytological and histological slides; 2) epithelial cells incorporating polymorphic nuclear neutrophils on cytological slides; and 3) positive immunohistochemistry of p53 protein. Diagn. Cytopathol. 1999;21:117-121.

Adult↗
PubMed1999

Immunohistochemical study of sialyl Le(a) and sialyl Le(x) antigen in oral squamous cell carcinoma: the association of sialyl Le(a) expression with the metastatic potential.

BACKGROUND: Carbohydrate antigens in cancer cells are considered to be involved in the binding of cancer cells to the endothelium during metastasis. METHODS: Seventy cases of primary oral squamous cell carcinoma (SCC) were obtained from biopsy specimens and were analyzed immunohistochemically using an antibody against sialyl Lewis (Le)a or sialyl Le(x). Flow cytometry was performed to detect the sialyl Le(a) or sialyl Le(x) expressed on oral SCC cell lines. RESULTS: The expressions of sialyl Le(a), but not sialyl Le(x), of primary tumors significantly correlated to nodal metastasis; 71% of the metastatic cases express sialyl Le(a) and the cases with positive sialyl Le(a) and no sialyl Le(x) demonstrated a high incidence of metastasis (80%). A flow cytometric study demonstrated the oral SCC cell line, which can metastasize in nude mice, to express a high level of sialyl Le(a). CONCLUSION: The high expression of sialyl Le(a) in primary tumors may thus be involved in nodal metastasis and therefore predict a poor prognosis in oral SCC.

Animals↗
PubMed1999

Developmental toxicity of indium in cultured rat embryos.

Developmental toxicity of indium was examined using rat embryo culture with reference to toxicokinetics. Rat embryos at day 9.5 of pregnancy were cultured for 48 h under various exposure conditions to indium trichloride. Indium was embryotoxic to cultured rat embryos at concentrations ranging from 25 to 50 microM for 24 h exposure according to the embryonic age, and the exposure concentration was more critical than the exposure time. The embryotoxic concentrations were comparable to the serum concentration at a developmentally toxic dose by intravenous administration in an in vivo experiment. It was considered from these results that the developmental toxicity of indium is a direct effect on the embryo or yolk sac and that weak developmental toxicity of indium by oral administration was due to low exposure concentrations in the embryo.

Animals↗
PubMed1999

Intravascular ultrasound imaging before and after balloon angioplasty for pulmonary artery stenosis.

Previous reports regarding intravascular ultrasound (IVUS) imaging of the pulmonary arteries in children and its application to balloon pulmonary angioplasty are limited. This study was designed to compare findings of IVUS imaging and those of angiography of the pulmonary artery before and after the balloon angioplasty procedure. Thirty patients had significant pulmonary artery stenosis and underwent balloon angioplasty. In all, of 34 branch pulmonary arteries were dilated. All patients underwent both angiography and IVUS imaging at the time of balloon angioplasty. The mean age at balloon angioplasty was 5.7 +/- 4.0 yr. One echo-dense layer on IVUS was detected in 9% of the 34 stenotic vessels, and a two- or three-layered vascular wall pattern in 91%. The thickness of intima-medial layer (inner and middle layers) was greater than normal in 91% of stenotic vessels. After balloon angioplasty, intimal flaps and aneurysm were observed at 29 and 28 locations, respectively. Of these locations, the intimal flaps were detected by angiography in 44% and by IVUS in 100%; the aneurysm was detected by angiography in 61% and by IVUS in 93%. Media rupture was observed at 26 locations, and the change was detected only by IVUS. The present study suggests that intimal and medial changes in the pulmonary artery can be detected more precisely by IVUS than by angiography.

Angioplasty, Balloon↗
PubMed1999

Hepatocyte growth factor supports androgen stimulation of growth of mouse ventral prostate epithelial cells in collagen gel matrix culture.

To assess the role of hepatocyte growth factor (HGF) and androgen in growth of prostate epithelial cells, we isolated mouse ventral prostate epithelial cells and cultured them in a three-dimensional type I collagen gel matrix under serum-free conditions. Although the prostate epithelial cells tended to die in the insulin-supplemented basal medium, 5alpha-dihydrotestosterone (DHT) prevented the cell death, and HGF slightly stimulated the growth. By contrast, coexistence of DHT and HGF greatly augmented the growth and branching morphogenesis of the epithelial cells. Some of the outgrowths formed under these conditions showed enlarged structures resembling the prostate ducts or alveoli. Examination of the stromal cell-conditioned medium revealed that a growth-stimulating activity is present in the conditioned medium. A major portion of this activity was abolished by anti-HGF IgG. These observations suggest that HGF is produced by the stromal cells of the prostate gland and supports the androgen stimulation of growth of the epithelial cells.

Animals↗
PubMed1999

Tumor angiogenesis, apoptosis, and p53 oncogene in stage I lung adenocarcinoma.

The purpose of this study was to clarify which factors are important as predictors not only of patient survival but also of hematogenic metastasis in 15 patients with stage I lung adenocarcinoma who underwent curative operation. The relationship between tumor angiogenesis, apoptosis, and p53 oncogene was also studied. A total of 15 patients were divided into two groups: surviving group (n = 7) and nonsurviving (metastasis) group (n = 8). We studied the medical charts, operative records, pathologic reports, and tumor specimens taken at surgical resection. We measured the apoptotic index using the ApopTag kit and the intratumoral microvessel count using an anti-CD34 monoclonal antibody. In addition, immunohistochemical staining for the expression of p53 was conducted simultaneously. The clinicopathological characteristics, including age, sex, tumor size (pT), and histological differentiation, were not significantly different between the surviving and the nonsurviving group. The microvessel count was significantly higher in nonsurviving group than in the surviving group. The apoptotic index and the expression of p53 was not significantly different between the two groups. An inverse correlation between the apoptotic index and microvessel count, and a positive correlation between the expression of p53 and microvessel count, were observed. Angiogenesis may be an important prognostic factor in patients with stage I lung adenocarcinoma.

Adenocarcinoma↗
PubMed1999

Protective effects of calpain inhibitor for prolonged hypothermic cardiac preservation.

PURPOSE: For successful organ transplantation, it is important to properly preserve the donor organ. This study was carried out to investigate tissue damage generated by the activation of calpain during prolonged hypothermic cardiac preservation using specific antibodies for mu- and m-calpain proenzymes, and to ensure the protective effect of calpain inhibitor 1 (N-acetyl-leucyl-leucyl-norleucinal). METHODS: Excised rat hearts were divided into two groups: in Group I, the heart was arrested and immersed in University of Wisconsin solution with 20 microM of calpain inhibitor 1 (n = 28) and in Group N, the heart was arrested and immersed in University of Wisconsin solution without calpain inhibitor (n = 27). After a 12-hour preservation period at 4 degrees C, the hearts were reperfused on an isolated perfusion apparatus. Separation of the myocardial calpain isozymes was carried out by DEAE cellulose chromatography and both calpain proenzymes were detected by immunoblotting. RESULTS: The cardiac function was more satisfactorily maintained in Group I in comparison with Group N. Remarkable leakage of creatine kinase, glutamic-oxaloacetic transaminase and lactate dehydrogenase was detected in Group N, while it was efficiently suppressed in Group I. During ischemia, mu-calpain proenzyme decreased in Group N (p < 0.01), but there was no significant change in m-calpain. However, during reperfusion, both mu- and m-calpains decreased more in Group N (p < 0.01). CONCLUSION: Activation of calpain proenzymes and a decrease in cardiac function during preservation and reperfusion were demonstrated. The use of calpain inhibitor to protect against tissue damage was suggested as being useful for the prolonged preservation of the heart.

Adenosine↗
PubMed1999

Giant trichoblastoma mimicking malignancy.

We report a case of giant trichoblastoma, a rare benign hair germ tumor. A 73-year-old man presented with a soft-tissue mass on his upper arm. Magnetic resonance imaging analysis revealed an unique mosaic pattern on T2-weighted images. Needle biopsy disclosed a keratinizing tumor suggesting squamous cell carcinoma. The size of the tumor was 9.5 x 7 x 9.5 cm, one of the largest trichoblastomas ever reported. The rarity and gigantic size of the tumor, together with its misleading clinical features, prompted us to report our case.

Aged↗
PubMed1999

The polymorphisms of DYS388 and DYS392 on the Y chromosome in Japanese and German populations.

The analysis of a genotype survey in Japanese and German populations at the loci DYS388 and DYS392 located on the Y chromosome is reported. The gene diversities of DYS388 were 0.34 and 0.30 in the Japanese and German males, respectively, and six alleles were found in both groups. The gene diversities of DYS392 were 0.65 and 0.64 and the number of alleles was 8 and 9, respectively in the two populations. The distribution of DYS388 alleles in the Japanese population was different from the German population. The allele distribution of DYS392 showed significant differences among Asian populations.

Asian People↗
PubMed1999

Definition and pathology of primary sclerosing cholangitis.

Although primary sclerosing cholangitis (PSC) is not a common disease, it is important in the differential diagnosis of hepatobiliary tract diseases in clinical practice. A diagnosis of PSC should be made only after the exclusion of similar diseases with well known etiologies or pathogeneses. In this review, the pathology of classical PSC and its variants or related diseases is highlighted. PSC is histologically characterized by progressive periductal fibrosis with luminal stenosis or obliteration, along with the formation of a fibrous core, as well as dilatation (cholangiectasis). Its etiology is unknown. Bacterial ascending cholangitis is superimposed on its long clinical course. Such a heterogeneous distribution of biliary lesions with biliary obliteration and cholangiectasis is responsible for the radiological demonstration of biliary abnormalities, particularly the beaded appearance. Sampling variability is common in needle or wedge biopsied specimens. As a result of biliary damage, the liver shows progressive cholestatic change followed by biliary fibrosis and cirrhosis, and this hepatic progression is divisible into four stages. There are several variants of PSC or related diseases, such as localized biliary sclerosis and stenosis, sclerosing cholangitis associated with inflammatory pseudotumor, and PSC-autoimmune hepatitis overlapping syndrome. Cholelithiasis, including secondary hepatolithiasis and, to a lesser degree, biliary carcinoma and dysplasia, are also known to develop at the perihilar bile ducts as a late complication of PSC.

Biliary Tract↗
PubMed1999

Functional imaging in periventricular nodular heterotopia with the use of FDG-PET and HMPAO-SPECT.

We analyzed the interictal [18F]fluoro-2-deoxy-D-glucose positron emission tomography (FGD-PET) and single photon emission computed tomography with technetium-99m-hexamethyl-propyleneamine oxime (HMPAO-SPECT) in two epileptic patients with periventricular nodular heterotopia (PNH). In both cases, we found both the glucose metabolism and the perfusion of PNH to be almost identical to those of the normal cerebral cortex. The metabolic activity and perfusion in the heterotopic gray matter in a subependymal white matter area probably represent the glucose metabolism and perfusion of the abnormally located gray matter rather than a subclinical ictal phenomenon. FDG-PET and HMPAO-SPECT were thus found to be a useful complement to magnetic resonance imaging in the evaluation of PNH.

Adult↗
PubMed1999

Functional imaging in schizencephaly using [18F]fluoro-2-deoxy-D-glucose positron emission tomography (FDG-PET) and single photon emission computed tomography with technetium-99m-hexamethyl-propyleneamine oxime (HMPAO-SPECT).

We analyzed interictal [18F]fluoro-2-deoxy-D-glucose positron emission tomography (FGD-PET) and single photon emission computed tomography with technetium-99m-hexamethyl-propyleneamine oxime (HMPAO-SPECT) in a 23-year-old female with schizencephaly. She had epilepsy and mild left hemiparesis, but was otherwise developmentally normal. We found the glucose metabolism and perfusion of the wall of the schizencephalic cleft to be identical to those of normal cerebral cortex. The wall of the transcerebral clefts, which were observed to be lined by abnormally organized gray matter as a result of a migration disorder, demonstrated gray matter metabolic activity and perfusion. FDG-PET and HMPAO-SPECT were thus found to be a useful complement to magnetic resonance imaging for evaluating schizencephaly.

Adult↗
PubMed1999

A case of infantile rhabdomyofibrosarcoma with immunohistochemical, electronmicroscopical, and genetic analyses.

A case of infantile rhabdomyofibrosarcoma arising on the buttocks of a 15-month-old boy is reported with histological, immunohistochemical, electronmicroscopical, and cytogenetic findings. Histological examination showed a proliferation of spindle-shaped cells in a fasciculated pattern, with occasional rounded rhabdomyoblastic cells with abundant eosinophilic cytoplasm. Immunohistochemically, the tumor cells expressed desmin and MyoD1 but were only weakly positive for myoglobin. No clear rhabdomyoblastic features were observed by electronmicroscopic examination. Chromosome analysis showed a clone of 46, XY, der(2)t(2;11)(q37;q13), different from any karyotypic abnormality in the original report of this neoplasm. Loss of heterozygosity at 11p15.5, the most frequent genetic alteration in embryonal rhabdomyosarcoma, was not detected. The low degree of striated muscle differentiation and tumor localization supported the diagnosis of infantile rhabdomyofibrosarcoma rather than spindle-cell rhabdomyosarcoma in this case. The present case has been uneventful as of 25 months after surgery. The rather long recurrence-free period, which has not been reported in previous cases, may be attributable to chemotherapy-induced rhabdoid differentiation of the tumor cells.

Cell Division↗