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Biomedical subjects

T Imamura

Publications and source records attributed to T Imamura.

At least 19 recordsLinked to original sources
PubMed1992

Flow cytometric analysis of nuclear DNA content of duct cell carcinoma of the pancreas.

BACKGROUND: This study was designed to evaluate the efficacy of nuclear DNA content analysis in determining the prognosis of carcinoma of the pancreas. METHODS: Resected and paraffin-embedded specimens from 72 patients with duct cell carcinoma of the pancreas were examined, and flow cytometry was used to explore the relationship between DNA ploidy and TNM classification or histologic grade. RESULTS: DNA aneuploidy was found histologically in 42.9%, 56.8%, and 71.4% of Grade 1, 2, and 3 tumors, respectively. DNA ploidy showed a statistically significant correlation with T category and retroperitoneal invasion. The cumulative survival rate of patients with retroperitoneal invasion was shorter than that of those without retroperitoneal invasion. Among the patients with retroperitoneal invasion, those with DNA aneuploidy had a significantly shorter survival time than did those with DNA diploidy. CONCLUSIONS: The DNA ploidy pattern, in combination with the presence or absence of retroperitoneal invasion, appears to be useful in predicting the prognosis for duct cell adenocarcinoma of the pancreas.

Adult↗
PubMed1992

A new biological activity of the complement factor H: identification of the precursor of the major macrophage-chemotactic factor in delayed hypersensitivity reaction sites of guinea pigs.

The guinea pig complement factor H(FH) and the plasma precursor(PMCFS-1) of the major monocyte-chemotactic factor(MCFS-1) found in the skin site of delayed hypersensitivity reaction(DHR) induced in the guinea pigs were compared in the antigenicity and the function. Both anti-FH-IgG and anti-MCFS-1-IgG formed a single precipitation line against FH, PMCFS-1, MCFS-1 and guinea pig plasma, and these lines fused one another without any spur formation. The inhibition activity of FH for C3bBb was absorbed by anti-MCFS-1-F(ab')2 in a dose-dependent manner. PMCFS-1 inhibited C3bBb activity dose-dependently as FH. These results show that FH is identical to PMCFS-1 and imply that FH, converted to MCFS-1 plays as a monocyte-chemotactic factor in the site of DHR.

Animals↗
PubMed1992

Chromosomal deletions and K-ras gene mutations in human endometrial carcinomas.

Forty-two endometrial carcinomas of various stages of progression were analyzed to search for loss of chromosomal regions and for point mutations of ras genes and amplification of Int-2 gene. This approach is particularly favorable for observation of genetic events and their significance in the process of neoplastic conversion by considering the clinico-pathological characteristics of each tumor. At least 3 genetic events, including 18q, 17p deletions, and point mutations at codon 12 of the K-ras gene, are implicated in the development of endometrial carcinomas. Likely targets for allelic losses on chromosomes 18q and 17p are the DCC gene and the p53 gene sequences, respectively. Overall numbers of allelic losses in individual tumors appeared to increase in case of advanced stage tumors, thereby indicating the association of allelic loss accumulation with tumor progression. The genetic features seen in 2 juvenile-type adenocarcinomas and 2 clear-cell carcinomas suggested the possibility that etiological factors providing selective pressure for particular mutation sub-sets during carcinogenesis are probably heterogeneous.

Adult↗
PubMed1992

Identification of a heparin-binding growth factor-1 nuclear translocation sequence by deletion mutation analysis.

We have shown previously that a deletion mutant of human heparin-binding growth factor (HBGF)-1, HBGF-1U, lacking the sequence Asn-Tyr-Lys-Lys-Pro-Lys-Leu is capable of initiating c-fos mRNA expression and polypeptide phosphorylation on tyrosine residues at concentrations that do not induce either DNA synthesis or cell proliferation (1). The fact that addition of the nuclear translocation signal from the yeast histone 2B protein to the HBGF-1U mutant caused reconstitution of the biological activity of HBGF-1 indicated that nuclear translocation may be an important component of the mitogenic signal induced by HBGF-1. In order to examine the nuclear translocation potential of HBGF-1 alpha, the deletion mutant HBGF-1U, and the yeast histone 2B-HBGF-1 chimera, HBGF-1U2, we expressed these forms of HBGF-1 in murine endothelial cells. Western blot and two-dimensional Western blot analysis of cytosol and nuclei demonstrate that although the three forms of HBGF-1 are readily detectable in the cytosol of the individual transfectants, HBGF-1 alpha and HBGF-1U2 but not HBGF-1U was detected in the nucleus. Furthermore, murine endothelial cells expressing HBGF-1 alpha and HBGF-1U2 exhibited an atypical cellular phenotype in vitro that was absent in the HBGF-1U transfectants. These data suggest that HBGF-1 contains a functional nuclear translocation sequence that may be responsible for the initiation of DNA synthesis, and these data further correlate the presence of the nuclear translocation sequence with an abnormal endothelial cell phenotype in vitro.

Animals↗
PubMed1992

Effect of 3-hour pancreatic duct obstruction on pancreatic lysosomal and digestive enzymes in rabbits.

We studied the effect of short-term (3 hours) pancreatic duct obstruction (PDO) on the exocrine pancreas and on the secretion of lysosomal enzymes into the pancreatic juice of rabbits during stimulation by pancreatic secretagogues. The following evaluations were made: serum amylase levels, pancreatic water content, pancreatic amylase, trypsinogen and cathepsin B content, and output of pancreatic enzymes and lysosomal hydrolases when stimulated by secretin and caerulein as well as the distribution of cathepsin B in subcellular fraction. PDO for 3 hours plus secretin infusion caused a significant rise in serum amylase levels, pancreatic water content, and pancreatic amylase and trypsinogen content due to congestion of digestive enzymes during PDO. There was also a redistribution of cathepsin B from the lysosomal fraction to the zymogen fraction. In normal rabbits and in those with only secretin infusion, caerulein stimulated the secretion of cathepsin B, into pancreatic juice. Just after PDO, the secretion of cathepsin B, amylase and trypsinogen significantly decreased. By 24 hours after PDO, the output of cathepsin B stimulated by caerulein and secretin had increased significantly. Amylase and trypsinogen output were also significantly increased at this stage, in both the secretin and caerulein fractions. These results indicate that the secretion of lysosomal enzymes into pancreatic juice is stimulated by gut hormones, such as caerulein, in the normal physiological state and in pathological states, such as PDO. These results also show augmented secretion of both lysosomal enzymes and pancreatic digestive enzymes in the recovery stage after PDO and their important roles at this stage.(ABSTRACT TRUNCATED AT 250 WORDS)

Amylases↗
PubMed1992

Capsaicin-sensitive nonadrenergic and noncholinergic depressor response to spinal cord stimulation in the pithed rat.

The effects of capsaicin on nonadrenergic, noncholinergic depressor responses to spinal cord stimulation were studied in pithed rats. Mean blood pressure (MBP was maintained at a level of 100 mmHg by continuous infusion of methoxamine and hexamethonium to block autonomic outflow. Electrical stimulation of the lower thoracic region (T9-12) via a pithing rod produced a frequency (1-8 Hz)-dependent fall in elevated MBP. The depressor response was abolished by tetrodotoxin, whereas atropine, propranolol, and cimetidine plus pyrilamine did not affect the response. Capsaicin treatment abolished the depressor response. These results suggest that spinal cord stimulation causes neurogenic vasodilation which is mediated by capsaicin-sensitive nonadrenergic and noncholinergic vasodilator nerves.

Animals↗
PubMed1992

The major plasma kallikrein inhibitor of guinea pig plasma.

A plasma kallikrein inhibitor in guinea pig plasma (KIP) was purified to homogeneity. KIP is a single chain protein and the apparent molecular weight is estimated to be 59,000 by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. In amino acid composition, KIP is similar to human and mouse alpha 1-proteinase inhibitors and mouse contrapsin. KIP forms an equimolar complex with plasma kallikrein in a dose- and time-dependent fashion. The association rate constants for the inhibition of guinea pig plasma kallikrein by KIP, alpha 2-macroglobulin, C1-inactivator and antithrombin III were 2.5 +/- 0.3.10(4), 2.4 +/- 0.4.10(4), 6.6 +/- 0.5.10(4) and 9.1 +/- 0.6.10(2), respectively. Comparison of the association rate constants and the normal plasma concentrations of the four inhibitors demonstrates that KIP is ten-times as effective as alpha 2-MG and other two inhibitors are marginally effective in the inhibition of kallikrein. KIP inhibits trypsin and elastase rapidly, and thrombin and plasmin slowly, but is inactive for chymotrypsin and gland kallikrein. These results suggest that KIP is the major kallikrein inhibitor in guinea pig plasma and the proteinase inhibitory spectrum is unique to KIP in spite of the molecular similarity to alpha 1-proteinase inhibitor.

Amino Acids↗
PubMed1992

A clinicopathological and immunohistochemical study of osteofibrous dysplasia, differentiated adamantinoma, and adamantinoma of long bones.

A clinicopathological and immunohistochemical study of 12 cases of osteofibrous dysplasia (OFD), two cases of differentiated adamantinoma, and five cases of adamantinoma of long bones is presented. Although OFD and differentiated adamantinoma showed similar radiologic findings, differentiated adamantinoma was more likely to be a recurrent lesion than osteofibrous dysplasia and seemed to require a more extensive surgical procedure. Immunohistochemically, cytokeratin- and vimentin-positive cells were seen in both OFD and differentiated adamantinoma. The positive cells were scattered in the former, and were both scattered and nest-like in the latter. Both these lesions, however, were negative for epithelial membrane antigen. Excluding two cases of Ewing-like adamantinoma, the other three cases of adamantinoma were also positive for cytokeratin and vimentin. These results suggest that these three lesions share the same histogenetic origin. The two cases of Ewing-like adamantinoma differ from tibial adamantinoma in their radiological, histological and immunohistochemical aspects, and seem to constitute a distinct variant of adamantinoma with a different histogenesis.

Adolescent↗
PubMed1992

Beta-thalassemia major resulting from a compound heterozygosity for the beta-globin gene mutation: further evidence for multiple origin and migration of the thalassemia gene.

We describe in a Japanese family beta zero-thalassemia resulting from a compound heterozygosity for a beta-globin gene mutation. One mutation is a C-to-T transition at IVS-2 nucleotide position 654 on the background of Mediterranean haplotype IX. Another mutation is a G-to-A transition at IVS-2 nucleotide position 1, associated with a novel haplotype XI. The occurrence of these mutations on various chromosomal backgrounds provides strong evidence for an interplay of gene migration, interallelic gene conversion, and multiple origins of the same mutation.

Adult↗
PubMed1992

Role of thrombin and plasmin in development of delayed hypersensitivity reaction in guinea pig skin.

Induration is a prominent feature of delayed hypersensitivity reaction (DHR), and fibrin deposition is the central mechanism. We studied the effects of two inhibitors of DHR on the activities of thrombin and plasmin in the extract of the skin site of DHR and compared the two activities in the site of DHR with those in the site of the Arthus reaction (AR) that lacks induration. Warfarin, an anticoagulant, inhibited thrombin activity and induration, but not plasmin activity. Ferritin, a blocker of a macrophage-dependent reaction, inhibited the two activities and induration. The lesion of DHR had three to four times the thrombin activity of the lesion of AR, and the activity paralleled the development of induration. In contrast, plasmin activity of the site of DHR was lower than that of the site of AR and was associated with the reduction of induration. The two protease activities in the site of AR did not correlate with the development of the AR lesion. These results suggest that thrombin and plasmin mediate the development of induration and that induration is produced by a synergistic effect of high thrombin activity and low plasmin activity in the site of DHR.

Amino Acid Sequence↗
PubMed1992

Microenvironment of tryptophan residues in beta-lactoglobulin derivative polypeptide-sodium dodecyl sulfate complexes.

The changes of microenvironment of tryptophan residues in beta-lactoglobulin A and its cyanogen bromide (CNBr) fragments with the binding of sodium dodecyl sulfate (SDS) were studied with measurements of the rates of N-bromosuccinimide (NBS) modification reactions by stopped-flow photometry. Two tryptophan residues of carboxyamidomethylated (RCM) beta-lactoglobulin A in the states of their complexes with SDS were clearly distinguishable by their differences in NBS modification rates. We confirmed by experiments with CNBr fragments containing trytophan residue. The modification rates of Trp 19 in RCM beta-lactoglobulin A-SDS complexes were about 10-fold smaller than those expected for tryptophan residues exposed entirely to the aqueous solvent. The Trp 61 was hardly changed. The change of rate constants for Trp 19 was virtually consistent with those observed when N-acetyl-L-trytophan ethylester was dissolved in SDS micelles. For various species of polypeptide-SDS complexes, all tryptophan residues were reactive to NBS and also, for some of them, the differences in NBS modification rates were observed between tryptophan residues on a common polypeptide chain. These results suggest micellar and heterogeneous bindings of SDS to polypeptides.

Cyanogen Bromide↗
PubMed1992

Coronary artery-cardiac chamber shunt: cineangiographic analysis.

Coronary artery-cardiac chamber shunts (CA-CC shunts) were observed in 101 out of 2267 consecutive patients (4.5%) receiving selective coronary angiography. In these patients, contrast medium injected into the coronary artery escaped directly into the cardiac chamber. CA-CC shunts were angiographically classified into the following two types. Type I: The endocardial layer was diffusely opacified, and contrast medium escaped into the cardiac chamber on systole (n = 83). Type II: Contrast medium escaped directly into the cardiac chamber via an undilated branch (n = 11). Type I and type II shunts were observed simultaneously in 7 patients. It is speculated that type I is a shunt via a persistent arterio-sinusoidal vessel, while type II is a shunt via a persistent arterio-luminal vessel. Both types were observed frequently (24.9%) in hypertrophic cardiomyopathy. The degree of CA-CC shunts in hypertrophic cardiomyopathy was not influenced by the presence or absence of myocardial squeezing. CA-CC shunts are considered to be due to an abnormality in the coronary microcirculation of the myocardium. We describe the angiographic features of the two types of CA-CC shunt and discuss their pathophysiological significance.

Adolescent↗
PubMed1992

Substance P as a potent stimulator of sneeze responses in experimental allergic rhinitis of guinea pigs.

Substance P was examined for sneeze-inducing activity and its involvement of sneeze responses in experimental allergic rhinitis. Substance P, dripped into a nostril of guinea pigs, at concentrations of 100 pM and above induced sneezing in a dose-dependent fashion. The activity of substance P was not affected by the previous subcutaneous injections of capsaicin that depleted substance P in nerve fibers. Histamine induced sneezing at concentrations of 30 mM and above and the activity was reduced by capsaicin treatment. The frequency of antigen-induced sneezing was proportional to the substance P content in nasal mucosa of sensitized guinea pigs treated with increasing doses of capsaicin; correlation coefficient 0.91. These results suggest that substance P plays an important role as a stimulator of sneeze responses in experimental allergic rhinitis in guinea pigs.

Animals↗
PubMed1992

Suppressive effect of LD78 on the proliferation of human hemopoietic progenitors.

LD78 is a cDNA newly isolated from human stimulated tonsillar lymphocytes. The expression of LD78 is related to inflammatory responses and its structure has a homology with macrophage inflammatory protein 1-alpha, which is known to have an inhibitory effect on murine CFU-S. Using a colony assay technique, we examined the effects of LD78 on human hemopoietic progenitors. The addition of doses of 100 ng/ml or more of LD78 suppressed the colony formation of KMT-2, a factor-dependent myelomonocytic cell line established from cord blood cells; this suppressive activity was neutralized by the addition of antibody against LD78. The same doses of LD78 suppressed the formation of neutrophil, macrophage, and megakaryocytic colonies which were supported by human interleukin-3 and erythropoietin; however, LD78 did not affect colony formation by either non-phagocytic mononuclear cells or sorted CD34+ cells. The conditioned medium of KMT-2 cells or peripheral blood mononuclear cells cultured with LD78 suppressed colony formation by CD34+ cells. From these findings, it is suggested that LD78 affects phagocytic cells and induces factors that are inhibitory for hemopoiesis. We consider LD78 to be a new cytokine that plays an inhibitory role in hemopoiesis.

Bone Marrow↗
PubMed1992

Hypergraphia associated with a brain tumour of the right cerebral hemisphere.

Two different neurobehavioural abnormalities have been reported under the term hypergraphia. One has been described in temporal lobe epilepsies and the other in the acute stage of strokes of the right cerebral hemisphere. The latter type of hypergraphia in a patient with a metastatic brain tumour confined to the right hemisphere is reported. Such hypergraphia is a general right hemisphere sign that is not peculiar to strokes in the acute stage and the writing behaviour is inattentive.

Adenocarcinoma↗
PubMed1992

Effect of capsaicin as a neuropeptide-releasing substance on sneezing reflex in a type I allergic animal model.

To elucidate the effect of capsaicin-sensitive nerve fibers, which are known to contain substance P (SP) and other sensory neuropeptides, on the sneezing reflex, we have investigated the effect of capsaicin on this reflex provoked in guinea pigs passively sensitized with anaphylactic antibody followed by specific antigen challenge. It has already been established that histamine released from mast cells is a reliable inducer of the sneezing reflex in type I allergy. Our experimental results indicated that the frequency of sneezing provoked by antigen challenge as well as histamine application was significantly reduced by pretreatment with capsaicin in a dose-dependent fashion. SP is considered to be one of the main neurotransmitters in sensory nerves. When the amount of SP in animal nasal mucosa was measured 12 h after capsaicin treatment, a marked reduction was noted. However, the histamine content in the nasal mucosa was not changed by capsaicin treatment. These data suggest that neuropeptides, especially SP, which are released or depleted from sensory nerves by capsaicin treatment, probably play an important role as neurotransmitters of the stimulant histamine in the development of sneezing in type I allergy.

Animals↗