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Biomedical subjects

H Miyamoto

Publications and source records attributed to H Miyamoto.

At least 91 records · Page 5Linked to original sources
PubMed2000

[A case of primary lung cancer complicated with post-operative intractable pulmonary fistula].

The case was a 76-year-old male. After thoracoscopic left upper lobectomy against primary lung cancer with poor risks such as complication of systemic lupus erythematosus (SLE) and pulmonary emphysema, oral steroid treatment, heavy smoker, decreased renal function, the patient was complicated with intractable pulmonary fistula and MRSA pyothorax. Intracavitary administration of albumin preparation and fibrin glue (Beriplast P) was effective against pulmonary fistula though it was not helpful in the pleurodesis which was conducted 7 times. Teicoplanin (Targosid) was effective against MRSA pyothorax and maintained the renal function.

Aged↗
PubMed2000

[A novel in vivo 31P-nuclear magnetic resonance technique for assessment of teratogenicity induced by environmental endocrine disrupters in mice].

Novel in vivo 31P-nuclear magnetic resonance spectoroscopy(NMR) and NMR-imaging techniques for accurate and noninvasive assessment of teratogenicity induced by environmental endocrine disrupters(EDs) were developed. Mice with pregnancy were administered ED at extremely low dose, and then in vivo 31P-NMR spectra of embryos were acquired noninvasively and quantitatively to evaluate the energy metabolism. A significant decrease in embryo ATP level was seen, but no significant changes were detected by conventional histological and biochemical methods. In conclusion, in vivo NMR techniques are highly sensitive(at least 100-fold more sensitive than conventional methods) and are useful for toxicological assessment of environmental pollutants.

Abnormalities, Drug-Induced↗
PubMed2000

The role of cyclooxygenase-2 and inflammatory cytokines in pain induction of herniated lumbar intervertebral disc.

Lumbar disc herniation (LDH) is the disease which is the major cause of radiculopathy. In terms of the pathogenesis of disease, it is reported that prostaglandinE2 (PGE2) plays an important role to induce radiculopathy. Arachidonate cascade, which is the process of PGE2 synthesis, is mainly regulated by two kinds of enzymes, phospholipaseA2 (PLA2) and cyclooxy genase (COX). Previously, PLA2 was recognized as the rate-limiting enzyme of this cascade, and some authors reported the clinical significance of PLA2 at the site of LDH concerning the radicular pain. Recently, COX was elucidated to consist of 2 types of isoform, a constitutive form of COX-1 and an inducible form of COX-2. COX-2 has been focused as a key enzyme to regulate PGE2 synthesis and plays an important role in inflammation, because COX-2 was induced in many types of cells by the stimulation of inflammatory cytokines such as interleukin-1 beta (IL-1 beta) and tumor necrosis factor alpha (TNF alpha). However, it is not fully discussed whether or not, COX-2 is induced in lumbar disc tissue and if it plays a significant role in the pathogenesis of LDH. To clarify the role of COX-2 in the pathomechanism of radiculopathy of LDH, we have investigated the expression of COX-2, IL-1 beta and TNF alpha in herniated lumbar disc tissue. Immunohistologically, they were detected in the cytosol of chondrocytes constituting the disc tissue. RT-PCR showed that herniated lumbar disc-derived cells expressed mRNA of COX-2, IL-1 beta and TNF alpha in the presence of inflammatory cytokines in vitro. The disc-derived cells also produced much PGE2 by stimulating of inflammatory cytokines at the same time and this PGE2 production was distinctly suppressed by a selective inhibitor of COX-2, 6-methoxy-2-naphtyl acetic acids (6MNA). These results suggest that COX-2 and inflammatory cytokines might play a causative role in the radiculopathy of LDH through upregulating PGE2 synthesis.

Adolescent↗
PubMed2000

Malignancy of the parotid gland with primary symptoms of a temporomandibular disorder.

The purpose of this case report is to highlight the possibility that malignant neoplasms of the deep lobe of the parotid gland may present as a temporomandibular disorder (TMD). Two patients who were eventually diagnosed with deep-lobe parotid tumors were retrospectively analyzed clinically, radiographically, and pathologically. For the first patient, there was a prolonged delay in establishing the correct diagnosis; for the second patient the delay was shorter. This was done primarily by computed tomographic examination. Despite aggressive surgical, radiotherapeutic, and chemotherapeutic treatment, both patients died from their malignant disease. All clinicians who treat TMD must be aware of the rare possibility of deep-lobe parotid tumors presenting as a TMD.

Adult↗
PubMed1999

Suppression of Delta(5)-androstenediol-induced androgen receptor transactivation by selective steroids in human prostate cancer cells.

Our earlier report suggested that androst-5-ene-3beta,7beta-diol (Delta(5)-androstenediol or Adiol) is a natural hormone with androgenic activity and that two potent antiandrogens, hydroxyflutamide (Eulexin) and bicalutamide (Casodex), fail to block completely the Adiol-induced androgen receptor (AR) transactivation in prostate cancer cells. Here, we report the development of a reporter assay to screen several selective steroids with anti-Adiol activity. Among 22 derivatives/metabolites of dehydroepiandrosterone, we found 4 steroids [no. 4, 1,3,5(10)-estratriene-17alpha-ethynyl-3, 17beta-diol; no. 6, 17alpha-ethynyl-androstene-diol; no. 8, 3beta, 17beta-dihydroxy-androst-5-ene-16-one; and no. 10, 3beta-methylcarbonate-androst-5-ene-7,17-dione] that have no androgenic activity and could also block the Adiol-induced AR transactivation in prostate cancer PC-3 cells. Interestingly, these compounds, in combination with hydroxyflutamide, further suppressed the Adiol-induced AR transactivation. Reporter assays further showed that these four anti-Adiol steroids have relatively lower glucocorticoid, progesterone, and estrogenic activity. Together, these data suggest some selective steroids might have anti-Adiol activity, which may have potential clinical application in the battle against the androgen-dependent prostate cancer growth.

Androstenediol↗
PubMed1999

Sequence analysis of Stx2-converting phage VT2-Sa shows a great divergence in early regulation and replication regions.

In enterohemorrhagic Escherichia coli, Shiga toxin is produced by lysogenic prophages. We have isolated the prophage VT2-Sa that is responsible for production of Shiga toxin type 2 protein, and determined the complete nucleotide sequence of this phage DNA. The entire DNA sequence consisted of 60,942 bp, exhibiting marked similarity to the 933W phage genome. However, several differences were observed in the immunity and replication regions, where cI, cII, cIII, N, cro, O, and P genes were present: Predicted amino acid sequences of N, cI, cro, O and P in the VT2-Sa genome did not show significant similarity to the counterparts of the 933W genome; however its cI showed higher similarity to lambda. Furthermore, O and P closely resembled those of phage HK022. These observations suggest that the various degrees of homology observed in the immunity and replication regions of VT2-Sa could have resulted from frequent recombination events among the lambdoid phages, and that these regions play a key role as a functional unit for phage propagation in competition with other lambdoid phages.

Amino Acid Sequence↗
PubMed1999

Cellular localization of adenosine A1 receptors in rat forebrain: immunohistochemical analysis using adenosine A1 receptor-specific monoclonal antibody.

Monoclonal antibodies were generated against the adenosine A1 receptor (A1R) purified from rat brain. In immunoblot analyses of purified or partially purified A1R preparations from rat brain, these antibodies recognized a solitary band, the size of which corresponded to that expected for A1R. These antibodies recognized not only the native form of A1R but also the deglycosylated form of A1R. Immunocytochemical analysis of Chinese hamster ovarian cells that were transfected stably with rat A1R cDNA showed that their cell bodies were stained intensely by these antibodies, whereas nontransfected Chinese hamster ovarian cells were not. These antibodies detected the A1R naturally present in the DDT(1)( )MF-2 smooth muscle cells. One of these antibodies (the 511CA antibody) was then used to examine the immunohistochemical distribution of A1Rs in rat forebrain. On light microscopy, A1R immunoreactivity was observed in the cerebral cortex, septum, basal ganglia, hippocampal formation, and thalamus. However, in some regions of the forebrain, regional differences in staining intensity were found as follows: In the cerebral cortex, the strongest immunoreactivity was found in the large pyramidal neurons of layer V. This immunoreactivity was detected in the pyramidal cell bodies, dendrites, and axon initial segments. In the hippocampus, A1R immunoreactivity was detected mainly in the stratum pyramidale. The pyramidal cells in fields CA2-CA3 of the hippocampus were stained more intensely or more clearly than those in field CA1 or the dentate gyrus. More intense A1R immunoreactivity of the apical dendrites was detected in field CA2 compared with other hippocampal fields and the dentate gyrus. Many interneurons of the hippocampus were stained by the 511CA antibody. The subcellular distribution of A1Rs in the forebrain was examined by using a digital deconvolution system and electron microscopy. In the cerebral cortex, the view obtained by removing the background haze by deconvolution revealed that the immunofluoresence-labeled A1Rs were distributed on the surfaces of the cell bodies and dendrites and in the cytoplasm of layer V neurons as small spots. In field CA1, immunoreactivity was detected in the areas surrounding pyramidal cells. Electron microscopy revealed the presence of A1R-immunoreactive products in both the presynaptic terminals and the postsynaptic structures. The specific cellular distribution of A1Rs is consistent with the physiological premise that endogeneously released adenosine exerts control over the excitability of forebrain neurons at both presynaptic and postsynaptic sites through A1Rs.

Animals↗
PubMed1999

Bacteriological investigation of an outbreak of Clostridium perfringens food poisoning caused by Japanese food without animal protein.

An outbreak of Clostridium perfringens food poisoning occurred in a senior citizen's home in Japan. Japanese food, spinach boiled with fried bean curd, was considered to be the causative food as a result of the detection of the C. perfringens enterotoxin gene by nested PCR. The number of enterotoxin-positive C. perfringens was enumerated as 4.3 x 10(5)/g in the causative food by the MPN method combined with nested PCR. By cultivation, enterotoxin-positive C. perfringens was isolated from all the fecal specimens of patients tested and the causative food. The isolates from patients were serotypable, heat-resistant and the majority produced enterotoxin, however most isolates from the causative food were nonserotypable, enterotoxin-negative and heat-sensitive.

Aged↗
PubMed1999

Separation of human cerebrospinal fluid proteins by capillary isoelectric focusing in the absence of denaturing agents.

Conditions of capillary isoelectric focusing (CIEF) to separate human cerebrospinal fluid (CSF) proteins were examined referring to those which we have established for the separation of human plasma/serum proteins. Since the average protein concentration in CSF is about 1/200 of plasma and the salt concentration is at almost the same level as plasma, desalting of CSF samples with minimum dilution was a prerequisite for CIEF analysis of CSF proteins. We constructed an apparatus to dialyze CSF at the level of 20-30 microL, this volume being sufficient for 3-4 repeated analyses of the CSF sample. To trace the process of dialysis, a simple device to measure the conductivity of the dialyzate was also constructed. Most of the CIEF conditions for plasma protein analysis could be applied for CSF protein analysis. However, the addition of N,N,N',N'-tetramethylethylenediamine (TEMED) at a suitable concentration was necessary to improve the resolution of basic proteins (IgG region), since some CSF patterns showed peaks of basic proteins which are not obvious in the serum of the same patient. About 70 peaks and shoulders of CSF proteins could be detected by the established CIEF technique. The results of CIEF analysis of CSF samples suggested that the technique will be useful as a survey method to detect specific proteins in CSF, which might relate to disorders in the central nervous system.

Blood Proteins↗
PubMed1999

Non-traumatic acute paraplegia associated with cervical disc herniation: a case report.

BACKGROUND: Acute paraplegia attributable to disc herniation is known to occur most frequently at the thoracic level. We report a rare case of non-traumatic acute paraplegia caused by disc herniation at the cervical level. Preoperative magnetic resonance imaging (MRI) of the present case demonstrated a spinal cord lesion as a cause of paraplegia. Although this symptom is believed to disappear rapidly after surgical treatment, there have been a few reported cases with poor neurologic recovery and permanent deficits. CASE DESCRIPTION: A 61-year-old female with a history of minor neck pain suffered from non-traumatic acute paraplegia attributable to cervical disc herniation. She underwent emergency surgery consisting of vertebrectomy, removal of herniated discs, and anterior fusion. Postoperative neurologic improvement was slow due to the cervical spinal cord lesion at the central portion of the cord, which was detected by the preoperative and postoperative MRIs. CONCLUSION: We emphasize that the MRI study is crucial for the management of patients with acute neck pain associated with cervical canal stenosis. Surgical treatment should not be delayed to avoid permanent neurologic deficits. Anterior decompression with vertebrectomy is recommended to decompress the injured spinal cord in the narrow cervical spinal canal; however, a cord lesion detected by MRI may indicate an incomplete surgical outcome.

Acute Disease↗
PubMed1999

A sheep model for temporomandibular joint ankylosis.

PURPOSE: The purpose of this study was to develop an animal model for temporomandibular joint (TMJ) ankylosis. MATERIALS AND METHODS: Five sheep had removal of the temporal and condylar articular surface plus discectomy in the right TMJ; the left side was used as a control. One sheep was killed just after operation and four at 3 months. The joints were examined histologically, and a scoring system was developed to evaluate the extent of the ankylosis. The range of jaw movement was compared between preoperatively and 3 months. RESULTS: Two sheep lost 4% of their body weight by 3 months. The range of jaw movement, particularly to the left, decreased at 3 months (P < .001). The joint spaces were filled with fibrous tissue and cartilage-like tissue. Development of new bone from the damaged temporal and condylar surfaces was seen, but full bony fusion did not occur. The average histologic score of a zone was 4.9 on the degree-of-ankylosis scale and 1.7 on the degree-of-calcification scale. There were statistically significant differences between the operated and control TMJs for both changes (P < .0001). CONCLUSION: Fibrous ankylosis occurs rapidly after removal of the TMJ articular surfaces and the disc. This model can be further developed to isolate relative factors in the development of ankylosis and in evaluation of different treatment methods.

Animals↗
PubMed1999

High level of adenosine A1 receptor-like immunoreactivity in the CA2/CA3a region of the adult rat hippocampus.

We describe the immunocytochemical distribution of adenosine A1 receptors in the rat hippocampus. Adenosine A1 receptor-like immunoreactivity was seen on the cell soma and dendrites of pyramidal cells and the cell soma and proximal part of dendrites of granule cells, but not on glial cells. Developmentally, adenosine A1 receptor-like immunoreactivity was diffuse on postnatal day 7 and increased in intensity in individual cells by day 21. In the CA2/CA3a region, the adult pattern of A1 receptor distribution was established by day 28. In the adult rat hippocampus, rostrocaudal inspection revealed that immunoreactivity in CA2/CA3a was greatest. Confocal microscopy revealed differences in the staining patterns for the adenosine A receptor and synaptophysin, a marker of presynaptic terminals. This result suggests that the adenosine A1 receptor might have postsynaptic physiological functions. Double-labeling of adenosine A1 receptors and anterogradely-labeled fibers from the supramammillary nucleus showed that the fibers from the supramammillary nucleus terminate directly on the cell soma of the A1 receptor-immunopositive neurons in CA2/CA3a and the dentate gyrus. These results indicate that the adenosine A 1 receptor in CA2/CA3a and the dentate gyrus are in a position to regulate hippocampal theta activity and that resultant strong synaptic depression in CA2/CA3a could play a role in regulating the intrinsic signal flow between CA3 and CA1.

Adenosine↗
PubMed1999

7-Chloro-5-hydroxy-1-[2-methyl-4-(2-methylbenzoyl-amino)benzoyl ]-2,3,4,5-tetrahydro-1H-1-benzazepine (OPC-41061): a potent, orally active nonpeptide arginine vasopressin V2 receptor antagonist.

We previously reported a series of benzazepine derivatives as orally active nonpeptide arginine vasopressin (AVP) V2 receptor antagonists. After the lead structure OPC-31260 was structurally evaluated and optimized, the introduction of the 7-Cl moiety on the benzazepine and 2-CH3 on the aminobenzoyl moiety enhanced its oral activity. The new AVP-V2 selective antagonist OPC-41061 was determined to be a potent and orally active agent.

Animals↗
PubMed1999

The role of the disk in sheep temporomandibular joint ankylosis.

OBJECTIVE: The purpose of this study was to determine the role of the disk in intraarticular ankylosis of the temporomandibular joint. STUDY DESIGN: Twelve adult sheep were divided into 2 groups. In group 1, removal of the temporal and condylar articular surfaces was performed on the right temporomandibular joint and the disk was maintained; in group 2, removal of the articular surfaces and diskectomy were performed on the right temporomandibular joint. One sheep from each group was killed just after surgery and 5 sheep from each group were killed at 3 months. The joints were examined radiologically, macroscopically, and histologically. The range of jaw movements was recorded preoperatively and at sacrifice. RESULTS: Each of 2 sheep in group 2 had lost 4% of their body weight by 3 months; all of the other sheep maintained or increased their weight. The range of jaw motion to the right was significantly lower in group 2 than in group 1 (P<.01). In group 1, fibrous repair of the articular surface and regeneration of the condylar head was seen. In group 2, each of the joints showed a total fibrous ankylosis with some calcification. There was a statistically significant difference in radiologic score between the groups (P<.0001). Histologic scores for group 1 demonstrated significantly lower scores on the degree of ankylosis scale and degree of calcification scale (P<.0001). CONCLUSIONS: This study showed that the presence of the disk prevented the development of fibrous intraarticular ankylosis of the temporomandibular joint.

Animals↗
PubMed1999

Arthroscopic surgery of the temporomandibular joint: comparison of two successful techniques.

We have compared two techniques of arthroscopic surgery for advanced internal derangement of the temporomandibular joint (TMJ). Patients with stage III or above TMJ internal derangement, who had not responded to three months of non-surgical treatment, were prospectively and randomly assigned to one of two types of treatment. One group had arthroscopic lysis and lavage (ALL) and the other had ALL plus arthroscopic anterolateral capsular release (AALCR). All patients were assessed preoperatively, and at 1, 3, 6, and 12 months postoperatively. Thirty-five patients (41 joints) had ALL and 66 patients (73 joints) had AALCR. The only significant difference was at 1 month, when the ALL group could not open their mouths as far as the AALCR group (P < 0.01). Both groups had significantly less pain in the joint and better jaw opening one year postoperatively. The stage of disease did not affect the outcome. Both ALL and AALCR gave good results in the management of advanced internal derangement of the TMJ. Unless early wide mouth-opening is required, the less invasive procedure of lysis and lavage should be chosen.

Analysis of Variance↗
PubMed1999

Suppression of experimental corneal angiogenesis by focal X-ray irradiation.

PURPOSE: To investigate the effect of focal X-ray irradiation on experimental corneal angiogenesis in the rabbit. METHODS: A gelatin hydrogel sheet impregnated with basic fibroblast growth factor was implanted into the corneal stroma of rabbits; this induced corneal angiogenesis. After the first sign of corneal angiogenesis was noted, the corneal region was irradiated with a dose of 10 Gy or 20 Gy. The control rabbits received no irradiation. The eyes were examined by slitlamp biomicroscopy and photographed, over a period of 28 days. The maximum length and total surface area of corneal angiogenesis were quantified by computerized image analysis. RESULTS: Corneal angiogenesis was noted on day 3 following implantation of the hydrogel sheet. In the rabbits irradiated with 10 Gy, the maximum length and total surface area of corneal angiogenesis were both significantly lower on day 4 and 7 following irradiation, compared to the respective measurement in the controls. In the rabbits irradiated with 20 Gy, the maximum length and total surface area of corneal angiogenesis were significantly lower between days 4 and 21, and between days 4 and 14, respectively, compared to the respective measurement in the controls. CONCLUSIONS: Focal X-ray irradiation to the corneal region suppressed corneal angiogenesis in a dose-dependent manner. Focal X-ray irradiation may be beneficial in treating ocular angiogenesis.

Animals↗
PubMed1999

Studies on cytogenesis in adult rat adrenal cortex: circadian and zonal variations and their modulation by adrenocorticotropic hormone.

Circadian rhythms and zonal variations in the cell proliferation of adult rat adrenal cortex were studied by following the cells in the DNA-synthesizing stage (S-phase) as assessed by 5-bromo-2'-deoxyuridine incorporation into the cell-nuclei and/or by visualizing proliferating cell nuclear antigen. The S-phase cells were observed throughout the day in two regions of the adrenal cortex: (i) a region from the inner half of the zona glomerulosa to near the outer margin of the zona fasciculata, and (ii) the outer one-fourth portion of the zona fasciculata. Very little change in number was observed in the former region between day and night, while a burst of cell proliferation occurred in early morning at 3-4 a.m. in the latter region. A prominent rise in the plasma adrenocorticotropic hormone (ACTH) concentration preceded the burst of cell proliferation by about 4 h. Upon raising the plasma ACTH concentration by administration of ACTH or metyrapone, prominent cell proliferation also occurred in the same portion of the zona fasciculata 4-6 h after the provoked ACTH surge. Thus at least two sites in rat adrenal cortex are responsible for cytogenesis in this endocrine organ, and respond differentially to day/night cycles and circulating ACTH levels.

Adrenal Cortex↗