Biomedical subjects

S Hirano

Publications and source records attributed to S Hirano.

At least 55 records · Page 3Linked to original sources

PubMed2001

Chemotactic responses of osteoblastic MC3T3-E1 cells toward zinc chloride.

Although zinc (Zn) is known to participate in bone formation, its exact role in the remodeling of this tissue has not been fully clarified. The present study was designed to investigate whether Zn has a role at the resorptive sites in vitro. We investigated the migration of osteoblastic MC3T3-E1 cells in response to Zn using a Boyden chamber assay. Exposure of MC3T3-E1 cells to Zn stimulated the migration of MC3T3-E1 cells. Checkerboard analysis revealed that the migration of MC3T3-E1 cells toward Zn was a directional (chemotaxis) rather than a random (chemokinesis) motion. Pretreatment of MC3T3-E1 cells with pertussis toxin completely blocked the chemotactic response of cells to Zn, indicating that it is mediated by G-protein-coupled receptors. Because the bone is one of the major Zn storage sites, we suggest that Zn released from bone-resorptive sites plays an important role in the recruitment of osteoblasts and bone renewal.

3T3 Cells↗

PubMed2001

Solitary true cyst of the pancreas in an adult: report of a case.

BACKGROUND: Solitary true cyst of the pancreas is rare in adults, and the differential diagnosis of cystic lesions of the pancreas is challenging. AIM OF THE STUDY: To describe a solitary true cyst of the pancreas in an adult and discuss the differential diagnosis. METHODS: A 50 yr old woman presented with a mass lesion in the right upper quadrant of the abdomen. Abdominal computed tomography showed a cystic lesion, with a maximum diameter of 12 cm, between the inferior surface of the liver and the ascending colon. The cyst was homogenous and had smooth edges. On magnetic resonance imaging, a unilocular cyst was seen that was low intensity on T1-weighted images and very high intensity on T2-weighted images. No connection between the cyst and the pancreatic ductal system was demonstrated on endoscopic retrograde cholangiopancreatography. Laparotomy was performed with a presumptive diagnosis of cystic tumor of the pancreas. RESULTS: On pathologic examination, the cyst was serous and was lined with a single layer of normal cuboidal epithelium that was periodic acid Schiff stain negative. Meticulous examination failed to identify honeycomb-like microcysts characteristic of serous cystadenoma. The final diagnosis was a solitary true cyst of the pancreas. CONCLUSION: The differential diagnosis of solitary true cyst from other cystic lesion of the pancreas usually is based on histology. Particular care must be taken to distinguish this lesion from macrocystic serous cystadenoma.

Diagnosis, Differential↗

PubMed2001

Functional defect of B lymphocytes in a patient with selective IgM deficiency associated with systemic lupus erythematosus.

Selective IgM deficiency (SIgMD) is a rare primary immunodeficiency disease, which is found in some patients with autoimmune diseases. The pathogenesis of SIgMD and the relationship of these diseases have remained unclear. The absence of secreted IgM was recently reported to accelerate the development of autoimmune diseases in lupus-prone lymphoproliferative (Ipr) mice. The reduction of secreted IgM production may relate with the progression of autoimmune diseases in human. We present a case of SIgMD associated with systemic lupus erythematosus (SLE), and examined the function and the IgM heavy chain gene of patient's lymphocytes. The number and the surface IgM expression of the patient's B cells were normal. In vitro stimulation of peripheral mononuclear cells by recombinant IL-2 and a B cell activator, Staphylococcus aureus Cowan strain I, could not overcome the reduction of IgM production, although the secreted form of IgM mRNA was detected. Sequence analysis of the IgM heavy chain gene and the IgM mRNA revealed no mutation or deletion. These findings suggested that SIgMD in this case was involved in the abnormality during B cell maturation. Further analysis is required to reveal the pathogenesis of SIgMD associated with SLE.

Antibody Formation↗

PubMed2001

[Proportion of aflatoxin B1 contaminated kernels and its concentration in imported peanut samples].

Moldy and split peanut kernels were separated from peanuts exported from Brazil, Sudan, India and Taiwan by visual inspection. The remaining peanuts from Brazil, Sudan and India were roasted lightly and the skins were removed. Stained peanuts were separated from the others. Aflatoxin was detected in moldy and stained peanuts. There was a positive correlation between % of aflatoxin-contaminated peanut kernels and aflatoxin B1 concentration in whole samples. Aflatoxin concentration of moldy peanuts was higher than that of stained peanut kernels.

Aflatoxin B1↗

PubMed2001

[Old adrenal hematoma: a case report].

A 75-year-old man was admitted to our hospital for closer examination of a left mass. Warfarin and calcium-antagonist for arrhythmia and hypertension had been administered for about 2 months before admission to our ward. Abdominal ultrasonography revealed a left adrenal mass 5 cm in diameter. Only serum noradrenalin was slightly elevated in endocrinological studies. In 131I-MIBG scintigraphy, uptake of radio-isotope at the adrenal gland was not revealed. Computed-tomographic (CT) scan showed left adrenal mass with a low density in the central area and iso-density in the peripheral area. The enhanced CT scan revealed enhancement in only the peripheral area of the left adrenal gland. Magnetic resonance imaging (MRI) showed a different intensity in the central area or peripheral area. Only the peripheral area of the mass was enhanced on dynamic MRI. Left adrenalectomy was performed. Histopathological examination revealed an old hematoma in the adrenal medulla without neoplasmic cells or vascular lesions.

Adrenal Gland Diseases↗

PubMed2001

[A girl with chief compliance of "easy to forget"--cognitive neuropsychological evaluations and cerebral blood flow].

Cognitive-neuropsychological evaluations were performed on a 12-year-old girl with memory disorder to study the higher brain function of this patient. The cerebral blood flow (r-CBF) was also studied. The results showed that the auditory-verbal memory of this patient were impaired. The regional cerebral blood flow was reduced in the left hippocampus which reportedly cause memory disorder. The disturbance of visual cognition and disability of construction in this patient seem to be related to reduced cerebral blood flow in the left parietal region.

Cerebrovascular Circulation↗

PubMed2001

A clustering method based on rough sets and its application to knowledge discovery in the medical database.

This paper proposes a clustering method for nominal and numerical data based on Rough Sets and its application to knowledge discovery in the medical database. Classification is performed according to the indiscernibility relations defined on the basis of relative similarity between objects. The similarity is defined as a combination of two types of similarity measures: the Hamming distance for nominal attributes and the Mahalanobis distance for numerical attributes. Excessive generation of small category is suppressed by modifying similar equivalence relations into the same equivalence relation. An analysis of the meningoencephalitis diagnosis database was performed to validate this method. The result showed that this method could deal well with both types of attributes and discover the primary factors for diagnosis.

Artificial Intelligence↗

PubMed2001

Radical distal pancreatectomy with en bloc resection of the celiac artery, plexus, and ganglions for advanced cancer of the pancreatic body: a preliminary report on perfect pain relief.

OBJECTIVE: The purpose of this study was to report the effect of radical distal pancreatectomy with en bloc resection of the celiac artery, plexus, and ganglions for locally advanced cancer of the pancreatic body on intractable abdominal and/or back pain and to explore the histopathologic mechanism of this pain. PATIENTS: Five patients with pancreatic body cancer involving the celiac and/or common hepatic artery underwent this radical surgery intended to cure the cancer. DESIGN: A retrospective analysis was performed. MAIN OUTCOME MEASURES: Surgical magnitude, postoperative pain control, postoperative outcome, and histopathologic findings were studied. RESULTS: Arterial reconstruction, gastrointestinal reconstruction, and blood transfusions were unnecessary. The organ deficit was limited to the distal pancreas, spleen and left adrenal gland. There was no postoperative mortality. Postoperative complications occurred in four patients, who were successfully managed with medical treatment. This led to prolonged hospital stays. The intractable preoperative abdominal and/or back pain was completely relieved immediately after surgery in all patients. Perfect pain control has been maintained from surgery to the last follow-up. Histopathologic examination of the surgical specimens revealed cancer invasion of the celiac plexus in all patients. CONCLUSIONS: This operation offers not only disease radicality but also perfect pain relief. The survival benefit has not yet been fully defined.

Abdominal Pain↗

PubMed2001

Changes in gait stability induced by alteration of mandibular position.

The purpose of this study was to investigate the effect of different mandibular positions on the body equilibrium by measuring the gait rhythm. Twelve young healthy subjects volunteered to participate in this study. Subjects were instructed to walk for a 18m distance with the mandible guided at six different positions by occlusal splints. The gait was recorded at fast, ordinary and slow walking speeds under occluded condition. Gait cycle, coefficient of variation for gait cycle and gait velocity were calculated during the 10m-walk. One-way ANOVA with repeated measures demonstrated significant differences among the six mandibular positions for the gait cycle at all gait speeds, for the coefficient of variation at fast speed and ordinary speed and for the gait velocity at fast speed (P<0.05). Regarding these variables, multiple comparison tests were also performed between the mandibular position without instruction for occlusion and other five mandibular positions. Gait cycle, coefficient of variation and gait velocity changed significantly in 5mm opening position from the intercuspal position, and in 5 mm left and 5mm right position from the 3mm opening position at fast speed (P<0.05). The result of this study suggests that the change of mandibular position could affect the gait stability.

Adult↗

PubMed2000

Lateral clustering of cadherin-4 without homophilic interaction: possible involvement in the concentration process at cell-cell adhesion sites as well as in the cell adhesion activity.

It is thought that the concentration of classic cadherins at cell-cell adhesion sites is essential for generating strong cell-cell adhesion activity, but the mechanism is not well understood. To clarify the structural basis of the concentration process and the cell adhesion activity, we constructed various mutants of cadherin-4 and examined the adhesion properties of the transfectants. A deletion mutant lacking the entire cytoplasmic domain had weak, but significant Ca(2+)-dependent cell adhesion activity. Interestingly, the deletion mutant showed intrinsic cluster formation in the absence of cell-cell adhesion, possible lateral cluster formation. The cytoplasmic domain-deleted cadherin-4 containing the mutation of Trp-2 to Ala, which is known to inhibit the strand dimer formation required for the cell-cell adhesion, retained the possible activity of lateral cluster formation, supporting this notion. These results suggest that the extracellular domain has intrinsic activity of lateral cluster formation. Indeed, deletion of a cadherin repeat in the extracellular domain significantly reduced or abolished the lateral cluster formation as well as the concentration of cadherin-4 at cell-cell contact sites and cell adhesion activity. When transfectants of the cytoplasmic domain-deleted cadherin-4 made cell-cell contact and formed intimate cell-cell adhesion, the lateral clusters of cadherin-4 initially gathered at cell-cell contact sites, and a smooth linear concentration was gradually formed along the cell-cell adhesion interface. The results suggest that the lateral cluster formation is involved in the concentration process of cadherin-4 at cell-cell adhesion sites, hence in the strong cell adhesion activity of cadherin-4 as well.

Amino Acid Substitution↗

PubMed2000

Pax1/Pax9-Related genes in an agnathan vertebrate, Lampetra japonica: expression pattern of LjPax9 implies sequential evolutionary events toward the gnathostome body plan.

Among the transcription factor gene families, Pax genes play important and unique roles in morphological patterning of animal body plans. Of these, Group I Pax genes (Pax1 and Pax9) are expressed in the endodermal pharyngeal pouches in many groups of deuterostomes, and vertebrates seem to have acquired more extensive expression domains in embryos. To understand the evolution of Pax1/Pax9-related genes in basal groups of vertebrates, their cognates were isolated from the Japanese marine lamprey, Lampetra japonica. RT-PCR of larval lamprey cDNA yielded two different fragments containing vertebrate Pax1- and Pax9-like paired domains. The Pax9 orthologue was isolated and named LjPax9. Whole-mount in situ hybridization revealed that this gene was expressed in endodermal pharyngeal pouches, mesenchyme of the velum (the oral pumping apparatus) and the hyoid arch, and the nasohypophysial plate, but not in the somitic mesoderm of the lamprey embryo. These expression patterns could be regarded as a link between the basal chordates and the gnathostomes and are consistent with the phylogenetic position of the lamprey. Especially, the appearance of neural crest seemed to be the basis of velar expression. Homology of the velum and the jaw is also discussed based on the LjPax9 expression in the first pharyngeal pouch and in the velar mesenchyme. We conclude that Pax9 genes have sequentially expanded into new expression domains through evolution as more complicated body plans emerged.

Amino Acid Sequence↗

PubMed2000

Mutation analysis of cadherin-4 reveals amino acid residues of EC1 important for the structure and function.

To clarify the structural basis of the cell adhesion activity of cadherins, we examined the effects of point mutations of well-conserved amino acid residues in the extracellular domain 1 of cadherin-4 (Cdh4) on the adhesion properties by alanine scanning mutagenesis. Mutations of two well-conserved aromatic amino acid residues in the extracellular domain 1 resulted in abnormal processing of Cdh4 molecules and no cell adhesion activity, whereas mutations of the corresponding aromatic amino acids in the extracellular domain 2 did not show these effects, suggesting a role for the two residues in the extracellular domain 1 in the folding and/or intracellular transport processes of Cdh4. Mutations of the amino acid residues suspected to be involved in strand dimer formation resulted in loss or significant decrease in cell adhesion activity. The mutant Cdh4s showed weak concentration at cell-cell adhesion sites and chemical cross-linking suggested that the strand dimer formation was actually impaired in the mutants. These results are consistent with the zipper model, in which the extracellular domain 1 of Cdh4 has intrinsic strand dimer formation activity in addition to adhesion dimer formation activity, both of which are involved in cell adhesion activity. The zipper model, however, needs further improvement to fully account for the present results.

Amino Acid Sequence↗

PubMed2000

Synthesis of NF-kappaB activation inhibitors derived from epoxyquinomicin C.

In order to develop new inhibitors of NF-kappaB activation, we designed and synthesized dehydroxymethyl derivatives of epoxyquinomicin C, namely, DHM2EQ and its regioisomer DHM3EQ. These derivatives were synthesized from 2,5-dimethoxyaniline in 5 steps. Since DHM2EQ was more active and less toxic than DHM3EQ, its stereochemical configuration was determined by X-ray crystallographic analysis. Each enantiomer of the protected DHM2EQ was separated by a chiral column and deprotected. DHM2EQ inhibited TNF-alpha-induced activation of NF-kappaB in human T cell leukemia cells, and also inhibited collagen-induced arthritis in a rheumatoid model in mice.

Animals↗

PubMed2000

Ultrastructural organization of transmitters in the cat lateralis medialis-suprageniculate nucleus of the thalamus: an immunohistochemical study.

The lateralis medialis-suprageniculate nuclear (LM-Sg) complex of the cat's posterior thalamus receives a rather wide variety of inputs from diverse cortical and subcortical areas. Previous ultrastructural studies of this nucleus demonstrated the presence of four types of vesicle-containing profiles and characterized some of these as gamma-aminobutyric acid (GABA)-containing terminals (Norita and Katoh [1987] J. Comp. Neurol. 263:54-67; Norita and Katoh [1988] Prog. Brain Res. 75:109-118). The present study has extended these observations by examining the immunoreactivity (ir) of LM-Sg, with antibodies raised against aspartate (Asp), glutamate (Glu), GABA, the acetylcholine (ACh) marker, choline acetyltransferase (ChAT), and substance P (SP), by using light and electron microscopy. Neuronal somata immunopositive for the excitatory amino acids (EAAs) Asp and Glu, were of medium size. EAA-ir terminals also were of medium size and contained round synaptic vesicles; they made asymmetrical synaptic contacts with dendritic profiles. Neuronal somata immunopositive for GABA were small. GABA-positive terminals also were small and contained pleomorphic synaptic vesicles; they formed symmetrical synaptic contacts with dendritic profiles. No neurons immunolabeled for ChAT were found. Terminals immunopositive for ChAT were small and contained round synaptic vesicles; these made symmetrical synaptic contacts, asymmetrical synaptic contacts, or both, of the en passant type with dendritic profiles. SP-immunolabeled neuronal somata were not found. Immunolabeled terminals were small, contained round synaptic vesicles, and made asymmetrical synaptic contacts with dendritic profiles. ChAT-ir and SP-ir axon terminals were not expressed evenly within LM-Sg. This difference in distribution suggests that within the LM-Sg, there may be a difference in specific sensory processing functions which correlate with transmitter type.

Animals↗

PubMed2000

Structure of insect chitin isolated from beetle larva cuticle and silkworm (Bombyx mori) pupa exuvia.

Chitin samples in a alpha-form structure were isolated from beetle larva cuticle and silkworm (Bombyx mori) pupa exuvia by treatment with 1 N HCl and 1 N NaOH. Chitosan was prepared by treating them in 40% NaOH containing NaBH(4). Chitin and chitosan were analyzed by X-ray, [13C]CP/MAS NMR, [13C]FT-NMR, and scanning electron microscopy (SEM) methods. Insect chitin degraded more readily than shrimp chitin when treated with 6 N HCl and the enzyme-chitinase. After treatment with 2 N HCl at 100 degrees C, the insect chitin crystallinity increased. N-deacetylation of insect chitin was easier than that of crustaceous chitin, and about 94% of the N-acetyl groups were removed in one treatment with 40% NaOH for 4 h at 110 degrees C. After treatment with 2 N HCl, 55% of the N-acetyl groups of silkworm chitin were removed under the same conditions. Beetle chitin showed a higher affinity for chitinase than shrimp chitin.

Animals↗

PubMed2000

Fluoride induces apoptosis by caspase-3 activation in human leukemia HL-60 cells.

Even though fluoride toxicity is increasingly being considered to be important, very little information is available on the mechanism of action of fluoride. In the present study, the toxicity of fluoride on human leukemia (HL-60) cells was investigated and the involvement of caspase-3 was also studied. Fluoride induced apoptosis in HL-60 cells in a dose- and time-dependent manner. Annexin staining and DNA ladder formation on agarose gel electrophoresis further revealed that HL-60 cells underwent apoptosis on exposure to 2-5 mM fluoride. Western blotting using polyclonal anti-caspase-3 antibody and mouse anti-human poly(ADP-ribose) polymerase (PARP) monoclonal antibody was performed to investigate caspase-3 and PARP activity. Fluoride led to the activation of caspase-3 which was evident by the loss of the 32 kDa precursor and appearance of the 17 kDa subunit. Furthermore, intact 116 kDa PARP was cleaved by fluoride treatment as shown by the appearance of a cleaved 89 kDa fragment. The results clearly suggest that fluoride causes cell death in HL-60 cells by causing the activation of caspase-3 which in turn cleaves PARP leading to DNA damage and ultimately cell death.

Apoptosis↗

PubMed2000

Nonfunctioning endocrine tumor of the pancreas with extrapancreatic growth and cyst formation: report of a case.

We report a case of nonfunctioning endocrine tumor of the pancreas with extrapancreatic growth and cyst formation. A 48-year-old woman was admitted to our hospital with an upper abdominal mass, which was detected during a routine medical checkup. The preoperative diagnosis was a solid cystic tumor of the pancreas. The tumor, which measured about 7cm in diameter, arose from the head of the pancreas and had a thin stalk, measuring about 1 cm in diameter. The histopathological diagnosis was a malignant nonfunctioning endocrine tumor of the pancreas. Cyst formation occurred in 67% of the reported cases with extrapancreatic growth in Japan. It is speculated that the cyst formation in this disease is related to the large size of the tumor and to the extrapancreatic growth.

Abdominal Pain↗

PubMed2000

Wet spun chitosan-collagen fibers, their chemical N-modifications, and blood compatibility.

Based on an in vitro test for an improvement of the blood compatibility of chitin by blending with tropocollagen, we prepared a novel biocompatible blended fiber and its chemically N-modified fibers. Each (1 g/30 ml) of a clear mixed solution of chitosan with tropocollagen or collagen and a clear solution of chitosan itself in aqueous 2% acetic acid-methanol (2:1, v/v) was spun through a viscose-type spinneret into an aqueous 5% ammonia solution containing 40-43% ammonium sulfate at room temperature to afford a white fiber of chitosan-tropocollagen blends (1.08-1.65 g/denier for the tenacity and 10.9-43.2% for the elongation). The tropocollagen content up to 50% by weight) in the blended fiber affected little their tenacity and elongation values. The blended fiber was chemically N-modified at the fiber state by treatment with a series of carboxylic anhydrides and aldehydes to afford the corresponding N-modified fiber (0.86-1.31 g/denier for the tenacity and 8.0-12.1% for the elongation). A transparent blended hydrogel of N-acetylchitosan (chitin) with tropocollagen was produced from the above mixed solution by treatment with acetic anhydride, and its membrane and sponge sheet were also prepared from the hydrogel.

Animals↗