PubMed Health⌕ Search

Biomedical subjects

Y Saitoh

Publications and source records attributed to Y Saitoh.

At least 19 recordsLinked to original sources
PubMed1992

Self-reactive repertoire of tight skin (TSK/+) mouse: immunochemical and molecular characterization of anti-cellular autoantibodies.

The tight skin (TSK/+) mouse has been proposed as an experimental model for progressive systemic sclerosis because of the biochemical alterations in collagen synthesis and pathological similarities to the human disease. Here, we report the analysis of tight skin mice sera for the presence of anti-cytoplasmic and anti-nuclear autoantibodies and determination of the frequency of hybridomas producing anti-cellular autoantibodies. The binding specificity of TSK mAbs to nuclear and cytoplasmic antigens such as keratin, actin, vimentin, and mitochondria was determined. Of 71 monoclonal antibodies that we have studied, only 3 appear to bind to foreign as well as self-antigens, indicating that the majority of these antibodies do not belong to the class of natural autoantibodies. Our results also showed that the frequency of hybridomas producing anti-nuclear and anti-cytoplasmic antibodies was higher in TSK mice than in C57BL/6 pa/pa, the control mouse strain, used in these studies. The results of the analysis of V gene usage showed that the majority of anti-cytoplasmic and anti-nuclear antibodies are encoded by genes from a restricted number of VH and VK genes families. In the sera of TSK mice we have detected the presence autoantibodies specific for cytoplasmic antigens in addition to anti-nuclear and anti-topoisomerase I antibodies which are characteristic of scleroderma. Since the presence of anti-cytoplasmic antibodies has not been described in scleroderma, the significance of their production in tight skin mice is not clear. However, the presence of such autoantibodies in the animal model provides a basis for investigation of this type of antibodies in human disease.

Actins↗
PubMed1992

Characterization of the phosphatase activity of a baculovirus-expressed calcineurin A isoform.

Calcineurin A was purified by calmodulin-Sepharose affinity chromatography from Sf9 cells infected with recombinant baculovirus containing the cDNA of a rat calcineurin A isoform. The Sf9-expressed calcineurin A has a low basal phosphatase activity in the presence of EDTA (0.9 nmol/min/mg) which is stimulated 3-5-fold by Mn2+. Calmodulin increased the Mn2+ stimulated activity 3-5-fold. Bovine brain calcineurin B increased the A subunit activity 10-15-fold, and calmodulin further stimulated the activity of reconstituted A and B subunits 10-15-fold (644 nmol/min/mg). The Km of calcineurin A for 32P-RII pep (a peptide substrate (DLDVPIPGRFDRRVSVAAE) for CaN), was 111 microM with or without calmodulin, and calmodulin increased the Vmax about 4-fold. The Km of reconstituted calcineurin A plus B for 32P-RII pep was 20 microM, and calmodulin increased the Vmax 18-fold without affecting the Km. CaN A467-492, a synthetic autoinhibitory peptide (ITSFEEAKGLDRINERMPPRRDAMP) from calcineurin, inhibited the Mn2+/calmodulin-stimulated activities of the reconstituted enzyme and the A subunit with IC50's of 25 microM and 90 microM, respectively. The reconstitution of the phosphatase activity of an expressed isoform of calcineurin A by purified B subunit and calmodulin may facilitate comparative studies of the regulation of calcineurin A activity by the B subunit and calmodulin.

Amino Acid Sequence↗
PubMed1992

Carcinoembryonic antigen levels of peripheral and draining venous blood in patients with colorectal cancer. Correlation with survival.

Correlations between preoperative carcinoembryonic antigen (CEA) levels of peripheral (p-CEA) and draining blood (d-CEA), the CEA gradient between d-CEA and p-CEA (d-p CEA gradient) levels, and survival after resection of cancer lesions were examined in 94 patients with colorectal cancer. Survival rates of patients with normal p-CEA and d-CEA levels and d-p CEA gradient levels (less than 5 ng/ml) were significantly better than those of patients with abnormal levels (greater than or equal to 5 ng/ml), and the 5-year survival rates were, respectively, 62%, 69%, and 72% in the former and 42%, 41%, and 35% in the latter. The differences in the 5-year survival rates between patients with normal and abnormal d-p CEA gradient, d-CEA, and p-CEA levels were 37%, 28%, and 20%, respectively. Furthermore, the positive rates of d-CEA levels (64%) and d-p CEA gradient levels (48%) were higher than that of p-CEA levels (36%). However, some significant differences in background variables also were found between the respective groups of patients with normal and abnormal p-CEA and d-CEA levels and d-p CEA gradient levels. These results suggest that patients with poor prognoses are examined more effectively by determining their d-p CEA gradient and d-CEA levels than their p-CEA levels, and that CEA may be expressed as a quantitative sum total of various pathophysiologic variables of patients with colorectal cancer but not as an independent prognostic variable.

Carcinoembryonic Antigen↗
PubMed1992

Targeting of gonadotropin-releasing hormone axons from preoptic area grafts to the median eminence.

Implantation of normal GnRH neurons can reverse many of the reproductive deficiencies that characterize hypogonadal (hpg) mice. Since the GnRH axons follow a stereotyped trajectory to their target we investigated the possibility that host brain regions adjacent to the graft might provide signals that induced this directional growth. The role of the adenohypophysis in GnRH axonal outgrowth was studied in mice with co-grafts of fetal preoptic area (POA) and pituitary and in hypophysectomized hosts. When fetal pituitaries were grafted together with the POA, immunoreactive GnRH fibers did enter the glandular tissue but they also grew into the host median eminence. Surgical removal of the pituitary of hpg hosts prior to POA graft placement was also compatible with GnRH innervation of the host median eminence although in some individuals that innervation pattern was confined to the more caudal aspects. The results of these two experiments suggest that the anterior pituitary gland may be an attractive target for GnRH axons but that this tissue is not essential for directed GnRH axonal outgrowth to its target. To determine if the median eminence itself could direct the growth of GnRH axons, co-grafts of POA and a fetal medial basal hypothalamic (MBH) block, which was predominantly median eminence, were made. Immunocytochemistry showed that an intragraft mini-median eminence was formed with a highly organized and robust GnRH innervation. Ultrastructural analysis indicated that these axons terminated near fenestrated capillaries. However, even under these conditions some GnRH axons exited into the host median eminence. It now seems likely that a cellular component of the median eminence can provide a signal to attract GnRH axons. Whether this signal is produced by the specialized ependymal cells, by the endothelia, or by meningeal (pial) components must now be tested.

Animals↗
PubMed1992

Factors influencing survival after endoscopic Nd:YAG laser surgery for unresectable advanced malignancies of the trachea.

The effects of endoscopic Nd:YAG laser surgery were studied in 36 patients with unresectable advanced primary and metastatic malignancies in the trachea with special reference to the factors influencing long-term survival. Overall effectiveness of YAG laser treatment was demonstrated in 34 of the 36 patients (94 per cent), while the overall 1, 3 and 5 year survival rates after the first laser treatment were 25 per cent, 13 per cent and 13 per cent, respectively. Neither histologic type nor the severity of clinical symptoms before laser treatment showed any significant influence on the survival curves, however, endoscopic findings of stenosis, the effect of laser treatment and irradiated longitudinal length were all significantly correlated with the survival curves. In other words, endoscopically protruding type tumors with a longitudinal length of irradiation of 3.0 cm or less, and good responses not only to laser treatment but also to other combined modalities are favorable factors for achieving long-term survival in patients with tracheobronchial malignancies undergoing endoscopic Nd:YAG laser treatment. Endoscopic Nd:YAG laser surgery is considered to be a promising part of the multi-modality treatment for unresectable advanced primary and metastatic malignancies of the trachea.

Aged↗
PubMed1992

Distribution of XhoI and EcoRI family repetitive DNA sequences into separate domains in the chicken W chromosome.

Fluorescence in situ hybridization using as probes three biotinylated or digoxigenin-labeled chicken W chromosome-specific repeating DNA units (0.7 and 1.1 kb XhoI family and 1.2 kb EcoRI family units) suggested that a large fraction of one arm of the W chromosome was occupied by the EcoRI family sequences and that pericentromeric regions were widely occupied by the XhoI family sequences. A minor fraction of the EcoRI family was also present in a narrow region in the proximal half of the other arm. There was a region in the distal half of the latter arm where sequences from neither family hybridized. Evolutionary aspects of the presence of different domains occupied by different repetitive families and the significance of the unhybridized distal region are discussed.

Animals↗
PubMed1992

The effect of dopamine on rat gastric motility.

The inhibitory mechanism of dopamine (DA) on rat gastric motility was investigated in association with DA receptors. Gastric movement was assessed according to the method of Jacoby et al and was expressed with the system of Ludwick et al. (1968). DA inhibited gastric movement in both the corpus and antrum in a dose-dependent manner. Domperidone, a specific antagonist of DA2 receptor, suppressed DA-induced inhibition of gastric movement in a dose-dependent manner. SCH23390, a specific antagonist of DA1 receptor did not affect DA-induced inhibition of gastric movement. LY171555, a specific agonist of DA2 receptor, inhibited gastric movement in both the corpus and antrum in a dose-dependent manner. SKF38393, a specific agonist of DA1 receptor, did not affect gastric movement. These results indicate that DA plays an important role in the inhibitory regulation of gastric motility, through DA2 receptor but not DA1 receptor.

2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-ben↗
PubMed1992

Overexpression of c-Ki-ras and c-fos in human pancreatic carcinomas.

The mRNA expression of protooncogenes c-Ki-ras, c-myc, and c-fos was studied in five pancreatic carcinomas and five normal pancreatic tissues using RNase protection assay and Northern blot analysis. The expression of those protooncogenes was detected in total mRNA from all specimens. However, the amounts in carcinomas and in normal tissues differed. C-Ki-ras mRNA in all the tumors was expressed up to sixfold more than in normal tissues. C-fos mRNA was also overexpressed up to tenfold in four of five tumors. In contrast, c-myc mRNA levels were varied and did not differ significantly between tumors and normal tissues. The results suggest that the overexpression of c-Ki-ras and c-fos mRNA are implicated in the development of pancreatic adenocarcinoma.

Adenocarcinoma↗
PubMed1992

Multicentric development of pancreatic intraductal carcinoma through atypical papillary hyperplasia.

We report a case of multiple intraductal carcinomas of the pancreas associated with diffuse atypical papillary hyperplasia. A 67-year-old Japanese man with a complaint of epigastric pain was examined by endoscopic retrograde pancreatography, which demonstrated multiple dilated branches of the pancreatic duct in the body and tail of the pancreas. Histologic examination on the resected pancreas showed diffuse atypical papillary hyperplasia in multiple dilated ducts associated with multiple intraductal carcinomas. Histologic features are described and multicentric carcinogenesis through atypical papillary hyperplasia is discussed.

Aged↗
PubMed1992

De novo expression of aromatase in gastric carcinoma. Light and electron microscopic immunohistochemical and immunoblot study.

We have performed immunohistochemical and immunochemical studies of steroidogenic enzymes involved in estrogen biosynthesis in 30 cases of gastric carcinoma in order to investigate possible in situ production of estradiol (E 2) in carcinoma cells. Positive incidence of immunoreactivity for E 2, testosterone (T), cholesterol side-chain cleavage enzyme (P-450 scc) and aromatase (P-450 arom) were 17/30 (56.7%), 11/30 (36.7%), 3/30 (10.0%) and 23/30 (76.7%), respectively on light microscopy. Estrogen receptor (ER) immunoreactivity was not observed in any of the 30 cases examined. Normal gastric mucosa was negative for P-450 arom and P-450 scc. Examination of serial sections revealed that immunoreactivity of E 2 and P-450 arom were located in the same cells of carcinomatous glands. Immunoelectron microscopy demonstrated that E 2 and P-450 arom were located along the membrane and cisternae of smooth endoplasmic reticulum (sER). Western blot analysis showed one major band of 55 kDa of P-450 arom in the gastric carcinoma tissues examined. Retrospective analysis of immunohistochemistry of E 2 in 108 cases of gastric carcinoma revealed that E 2 positive carcinoma cases were likely to demonstrate better survival rate than negative cases. These results above strongly suggest that E 2 is produced by de novo expressed aromatase in gastric carcinoma cells and is possibly involved in the biology of gastric carcinoma cells.

Aromatase↗
PubMed1992

Papillary adenoma of the pancreas with excessive mucin secretion.

A 68-year-old woman with papillary adenoma of the pancreas with excessive mucin secretion is reported. The patient was initially diagnosed as having chronic pancreatitis because of a history of repeated attacks of pancreatitis and localized dilatation of the main pancreatic duct. Four years later, endoscopic retrograde pancreatography showed markedly diffuse dilatation of the entire main pancreatic duct with amorphous filling defects of mucin. Excretion of mucin was observed through the enlarged orifice of Vater's ampulla. The patient was treated with distal pancreatectomy, and papillary adenoma with abundant mucin in the cytoplasm was histologically demonstrated. We describe unique clinical features of "mucin-producing pancreatic tumor" and discuss an important role of endoscopic retrograde pancreatography in the diagnosis.

Ampulla of Vater↗
PubMed1992

The mechanism of action of the two-layer (Euro-Collins' solution/perfluorochemical) cold-storage method in canine pancreas preservation--the effect of 2,4 dinitrophenol on graft viability and adenosine triphosphate tissue concentration.

Tissue concentrations of adenosine triphosphate have been previously associated with successful pancreas preservation using the two-layer cold storage method in a canine autotransplantation model. To clarify the role of ATP vs. oxygenation per se, we used 2,4 dinitrophenol, an uncoupler of mitochondrial oxidative phosphorylation. DNP caused no toxicity in pancreas grafts preserved for 24 hr in Euro-Collins' solution or 48 hr in University of Wisconsin solution. Tissue concentration of ATP and viability of pancreas grafts, defined as maintenance of normoglycemia for 5 days following transplantation, were compared among six groups after a preservation interval of 24 or 48 hr. After 24 hr all grafts were viable, whether preserved using simple cold storage in EC (group 1a), two-layer (EC/perfluorochemical [PFC]) method (group 2a), or two-layer (EC+DNP/PFC) method (group 3a); respective graft survival was 4/4 (100%), 5/5 (100%), and 4/5 (80%); one of five dogs in group 3a died of a cause unrelated to the pancreas. ATP levels were higher in group 2a compared with group 1a (7.47 +/- 0.47 vs. 1.41 +/- 0.53 mumol/g dry weight, P less than 0.01) and lower in group 3a compared with group 2a (1.25 +/- 0.37 vs. 7.47 +/- 0.47, P less than 0.01). After 24 hr, we observed no difference in viability despite ATP concentration differences. However after 48 hr preservation, graft viability varied among the groups: 0/4 (0%), 4/4 (100%), and 0/3 (0%) in groups 1b, 2b, and 3b, respectively. ATP tissue concentration was again higher in group 2b after two-layer (EC/PFC) method preservation (7.91 +/- 1.21 vs. 1.21 +/- 0.31 mumol/g dry weight, P less than 0.01) compared with EC preservation (group 1b). DNP again caused a significant decrease in tissue ATP in group 3b (0.61 +/- 0.07 vs. 7.91 +/- 1.21, P less than 0.01). The two-layer (EC/PFC) method clearly protected pancreas viability, and inhibition of ATP production using DNP caused loss of viability in this model. We conclude that oxygenation of the pancreas during preservation by the two-layer method allows continued ATP production within the graft. Metabolic processes vital to cellular integrity can be maintained, which produces an extended period of preserved pancreatic viability.

2,4-Dinitrophenol↗
PubMed1992

A muscle fatigue index based on the relationship between preceding background activity and myotatic reflex response (MRR).

A new index of muscular fatigue was developed using the myotatic reflex response (MRR). The MRR of masseter muscles is evoked by periodical mechanical chin tapping during clenching. The MRR waveform is composed of somewhat synchronized action potentials of muscle fibers. We estimate the change of the MRR waveform due to fatigue using the instantaneous frequency pattern (IFP) with the Hilbert transform. As a result, the features of IFP were different from the monotonic changes that have been observed by the conventional fatigue indices. That is, a plateau IFP was observed ahead of considerable fatigue, whereas the IFP showed a monopeak pattern during other phase of an exercise. Also, the relationship between the preceding background mean power frequency and the instantaneous frequency around the first part of the MRR waveform was nonlinear during the whole process of fatigue. These features may allow us to estimate the degree of fatigue at each time instant. Although the details have not yet been solved, by using the computer simulations one of them seemed to be the alteration of the dominant frequency components. The dominant frequency components may be related to the active muscle fiber types.

Action Potentials↗
PubMed1992

Investigation on parametric analysis of dynamic EMG signals by a muscle-structured simulation model.

In the analysis of electromyographic (EMG) signals during dynamic movement, we have proposed an estimation algorithm for the time-varying parameters of an autoregressive model. The parameters correspond to less biased time-varying reflection coefficients. We determined the less biased estimation using a locally quasi-stationary model and named these parameters "k parameters." We estimated k parameters up to the fifth order for the surface EMG signals of a masseter muscle during rapid open-close movement of the lower jaw, a ballistic contraction, and fatigue. According to the results, the time courses of the k parameters displayed remarkable properties. In order to study the behavior of k parameters physiologically, we produced a muscle-structured simulation model based on anatomical and physiological data. The simulation results suggested that the behavior of the third parameter is related to the number of active motor units (MU's) at the shallow layer of a muscle. The detailed recruitment mechanism in terms of the MU's types has not yet been solved. Although further study is required, the parametric analysis using k parameters offers a new perspective for evaluation of muscle dynamics during several movements.

Algorithms↗
PubMed1992

Protective effect of a microtubule stabilizer taxol on caerulein-induced acute pancreatitis in rat.

The effect of taxol, which is a microtubule stabilizer, was examined in a model of acute edematous pancreatitis induced in rat by the administration of caerulein. Prophylactic administration of taxol ameliorated inhibition of pancreatic secretion, increased level of serum amylase, pancreatic edema, and histological alterations in this model. Immunofluorescence studies revealed that taxol stabilized the arrangement of microtubules by the action of promoting tubulin polymerization and prevented inhibition of pancreatic digestive enzyme secretion. In isolated rat pancreatic acini, taxol reversed the inhibition of amylase secretion induced by supramaximal concentrations of cholecystokinin octapeptide and did not affect the binding of cholecystokinin octapeptide to its receptor. The results obtained in this study suggest that microtubule disorganization is the initiating event in caerulein-induced pancreatitis and that the inhibition of pancreatic digestive enzyme secretion by interfering with intracellular vesicular transport due to microtubule disorganization causes caerulein-induced pancreatitis.

Acute Disease↗