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Biomedical subjects

M Mizutani

Publications and source records attributed to M Mizutani.

At least 145 records · Page 8Linked to original sources
PubMed1993

beta,beta'-Iminodipropionitrile toxicity in normal and congenitally neurofilament-deficient Japanese quails.

Morphological effects of a neurotoxin, beta,beta'-iminodipropionitrile (IDPN) were analyzed in normal and congenitally neurofilament (NF)-deficient Japanese quails. These quails (6 weeks old) were injected intraperitoneally with IDPN (0.2 g/kg body weight) three times every 3 days. They were necropsied at 10 to 12 days after the first injection. In normal quails, axonal swellings were observed histologically in the ventral motoneurons, ventral root, commissura grisea and spinal ganglion in the cervical and synsacral spinal cord. Electron microscopically, the changes consisted of increased NFs, with scattered mitochondria, smooth endoplasmic reticulum and microtubules. The myelin sheaths of the involved nerves were thinner than those of the normal axons. These lesions were similar to those induced by IDPN intoxication in mammalian experimental animals. In NF-deficient quails injected with IDPN, no axonal changes were detected. These findings suggested that IDPN selectively attacked the NFs.

Animals↗
PubMed1993

Smaller number of large myelinated fibers and focal myelin thickening in mutant quails deficient in neurofilaments.

The peripheral nervous system of a mutant of a Japanese quail deficient in neurofilaments (mutant) and of a normal Japanese quail (control) was morphometrically evaluated to characterize the morphological findings, especially those of the myelinated fibers of the mutant. In the proximal peroneal nerves, the frequency of the teased myelinated fibers showing the focal myelin thickening was higher in mutant than in control (P < 0.001) without obvious ongoing axonal degeneration and segmental demyelination. The total numbers of the myelinated fibers in the proximal and distal peroneal nerve, and in the tibial nerve branch to gastrocnemius muscle (pars medialis) were similar between control and mutant, although the number of the large myelinated fibers was less (P < 0.01) and the number of the small myelinated fibers was greater (P < 0.01) in mutant compared with control. The median diameters of neuronal cell bodies of the sacral dorsal root ganglia were similar in control and mutant. The percentages of light, dark and unclassified cells evaluated based on the histologic cytoplasmic features were also similar in control and mutant. Therefore, morphometric alterations were more pronounced in the peripheral myelinated nerve fibers compared with those in the cell bodies of the spinal dorsal root ganglia. We concluded that a smaller number of large myelinated fibers with a greater number of small myelinated fibers and the presence of focal myelin thickening are the main morphologic findings in this mutant, probably due to the arrest of radial growth or maturation of the axons of the myelinated fibers in the absence of ongoing myelinated fiber degeneration.

Animals↗
PubMed1993

Progression of a weakly tumorigenic mouse fibrosarcoma at the site of early phase of inflammation caused by plastic plates.

To elucidate tumor progression-enhancing factor(s), we examined the effects of host inflammation and host immunological status on in vivo tumor progression. One x 10(4) cells of QR clones (QR-32, -20 and -18), regressor tumor clones of 3-methylcholanthrene-induced fibrosarcoma, were unable to grow when injected s.c. into C57BL/6 mice in cell suspension form. However, QR clones grew and were lethal when s.c. implanted, attached to plastic plates. Furthermore, the tumor lines (QRpP) obtained from the tumors which had arisen from the plate-attached QR-32 clone cells no longer required plastic plates for their growth in normal mice, and had acquired stable malignant phenotypes. Although QR-32 cells became lethal when injected at the site of plastic plate implantation 1, 5 and 10 days before tumor injection, few tumors developed when plastic plates had been implanted 20 or 30 days before tumor injection. We established culture clones from the tumors arising in normal mice and mice immunosuppressed by irradiation. Clones derived from the tumors which had arisen in normal mice after implantation with plastic plates were lethal when re-implanted in normal mice (71%). On the other hand, clones derived from the tumors that arose in irradiated mice with or without plastic plates were lethal in only a few normal mice, when re-implanted (20 and 8%, respectively). These results indicate that QR clone cell progression is enhanced by the early phase of inflammation at the site of plastic plate implantation and that the progression-enhancing activity of co-implantation with a plastic plate is inhibited by previous whole-body irradiation of hosts.

Animals↗
PubMed1993

Role of 5-HT3 receptors in peristaltic reflex elicited by stroking the mucosa in the canine jejunum.

1. The role played by the 5-HT3 receptor, a serotonin subtype receptor, in peristaltic reflexes was studied in dogs first given ketamine, then anaesthetized with urethane (1.0 g kg-1, I.V.) and alpha-chloralose (100 mg kg-1, I.V.). The jejunal loop was partitioned into two segments with respect to blood supply. Drugs were infused intra-arterially into each segment. 2. Stroking of the mucosa of the aboral and oral segments elicited an ascending contraction and a descending relaxation, respectively. 3. The ascending contraction was concentration-dependently inhibited by treatment of the aboral segment with the 5-HT3 receptor antagonists ICS 205-930 and ondansetron (1.4 pmol min-1 to 14 nmol min-1 for both). The maximal inhibition was 49.5 and 69.3%, respectively. The response was not affected by treatment of the oral segment with these drugs. The descending relaxation was inhibited by 51.4 and 60.8%, respectively, by treatment of the oral segment with ICS 205-930 and ondansetron (1.4 nmol min-1 for both). 4. The ascending contraction was markedly inhibited by treatment of either segment with hexamethonium (140 nmol min-1). The response was abolished by treating both segments with hexamethonium and by treating the oral segment with atropine (14 nmol min-1). 5. These results suggest firstly that, in the canine jejunum, enteric neurons with 5-HT3 receptors play a role as sensory neurons or interneurons in the ascending excitatory and the descending inhibitory pathways of the peristaltic reflex elicited by stroking the mucosa, and secondly, that the ascending limb is composed of cholinergic interneurons and motoneurons.

Animals↗
PubMed1993

[Application of DNA fingerprinting to investigation of genetic relationships between laboratory rabbit strains].

It is well known that laboratory rabbits are not controlled genetically like laboratory mice and rats. In order to test the usefulness of DNA fingerprinting in investigation of genetic uniformity of the laboratory rabbits strains and their relationships, we applied DNA fingerprinting using bacteriophage M13 probe to five strains (2 inbreds (JWY-NIBS and DuY-NIBS) and 3 outbreds (JW-NIBS, Icl:JW and WHHL)). DNA fingerprints of 2 inbred strains showed the same banding patterns within each strain but the strain-specific patterns. Although there were no rabbits showing the same banding patterns in 3 outbred strains, average percent differences (APD) were 13.7 to 18.6. A dendrogram based on APD of DNA fingerprints was constructed by 2 large clusters, JW group and DuY. The dendrogram was essentially similar to that based on rabbit mandible measurements. These results suggest that DNA fingerprinting is available not only for the genetic monitoring of the laboratory rabbit strains but also for the investigation of their genetic relationships.

Animals↗
PubMed1993

Hemodynamic effects of lipo-PGE1 on peripheral artery in patients with diabetic neuropathy: evaluated by two-dimensional color Doppler echography.

Twenty non-insulin-dependent diabetic patients were studied to evaluate the hemodynamic effects of lipo-PGE1 (prostaglandin E1 incorporated in lipid microspheres). Improvement of diabetic neuropathy was assessed on the basis of subjective symptoms such as pain, coldness, numbness and dysethesia (subjective) after intravenous administration of lipo-PGE1. After lipo-PGE1 treatment, the subjective symptoms were markedly improved. Hemodynamic effects of this drug on the dorsalis pedis artery were examined using new real-time two-dimensional color Doppler echography. After administration of lipo-PGE1, the cross-sectional area of the dorsalis pedis artery significantly increased from 2.6 +/- 0.2 mm2 to 3.5 +/- 0.2 mm2 (P < 0.01). Moreover, the blood flow index significantly increased from 40 +/- 7 to 61 +/- 11 (P < 0.05). The results of this study suggest that lipo-PGE1 may serve as a useful drug in improving diabetic neuropathy.

Adult↗
PubMed1993

[Hard palate shape in the Japanese and Indian children on moiré topography with lateral movement of a grating].

In the present study, the hard palate of Japanese and Indian children was investigated. These children lived in different geographical areas and have different cranial characteristics, pronunciation and eating habits. Fifty-one Japanese children (26 boys and 25 girls, 3 years of age) and 66 Indian school children (31 boys and 35 girls, 5-7 years of age). The maxillary negative cast models were observed and three-dimensional measurements were taken of the hard palate with moiré Topography. The following results were obtained. 1. The palatal width and length in Japanese children was larger than the Indian children, but not in palatal height. The palatal height was significantly larger in the Indian children than in the Japanese children. 2. Observation of the moiré fringes on the deepest palate by moiré Topography shows that the Japanese children and Indian girls have a higher incidence of Crosswise type than Lengthwise type. The Indian boys have a slightly higher incidence of Lengthwise type than Crosswise type. The girls have a higher incidence of the Butterfly and Separate types than the boys. 3. The anteroposterior location on the deepest palate by moiré Topography: the Japanese children have significantly higher incidences of anterior location than the Indian children. Changes of anteroposterior location between the ages of 5 and 7 in the Indian children: the prevalence of posterior location appears to increase with age. 4. The hard palate shapes of the Japanese children appear to be broad and shallow, but those of the Indian children appear to be narrow and deep. This difference appears to be more remarkable in the boys. The shape and size of the hard palate appears to be due to genetic differences, in addition to the weather conditions, pronunciation and eating habits.

Anthropometry↗
PubMed1993

[On the fluctuation of plasma biopterin levels for 24 h in normal controls].

Tetrahydrobiopterin (BPH4) is the cofactor for the pteridine-dependent monooxygenases, which play important roles in the biosynthesis of cateholamines and indolamines. These biogenic amines have been thought to be related to affective disorders, and the increase of total biopterin (BP) and the lower ratio of BPH4 to total BP were observed in plasma of patients with affective disorders. For the purpose of giving an explanation of these changes of plasma biopterin mentioned above in patients with affective disorders, the fluctuation of plasma biopterin levels for 24 h was measured by high-performance liquid chromatography with fluorescence detection by the method of Fukushima and Nixon in ten normal volunteers. The total BP and BPH4 levels in plasma at 9 am were the highest, and those levels at 1 am were the lowest. The range of the fluctuation of total BP with the passage of time was narrow compared with the range of the increase of total BP observed in the patients with affective disorders. Other factors in addition to the fluctuation of plasma BP for 24 h were thought to be related to the changes of plarma BP levels in the patients with affective disorders.

Adult↗
PubMed1993

Glomerular localization of thrombomodulin in human glomerulonephritis.

BACKGROUND: Thrombomodulin (TM), a glycoprotein expressed on the surface of endothelial cells, transforms protein C into a potent anticoagulant by binding thrombin. TM may be an important regulator of intraglomerular coagulation because functional TM activity was demonstrated in glomeruli isolated from normal human and rat kidneys. The role of TM in glomerulonephritis is unknown. EXPERIMENTAL DESIGN: Sections from 4 normal human kidneys and from kidneys of 100 patients with various forms of glomerulonephritis were studied by light and transmission electron microscopy, and by light and electron immunohistochemical techniques using polyclonal antibodies to recombinant human TM, and monoclonal antibodies to the membrane attack complex of the complement system. The expression of TM was graded from 0 to 4 according to the intensity and extent of the distribution, and the results were compared with the clinicopathologic findings. RESULTS: In normal glomeruli and in glomeruli with minimal abnormalities, a small amount of TM was localized at the vascular pole only (grade 0-1). In membranoproliferative glomerulonephritis and lupus glomerulonephritis, the amount of TM found on the plasma membrane of endothelial cells was significantly increased (grades 2 to 4). The expression of TM was directly correlated with proteinuria (p < 0.001), glomerular hypercellularity (p < 0.01), and number of subendothelial immune deposits (p < 0.01). In contrast, in other forms of glomerular diseases, TM was not increased and no correlation was found with the clinicopathologic parameters. CONCLUSIONS: In membranoproliferative glomerulonephritis and lupus glomerulonephritis, the amount of TM expressed by the plasma membranes of glomerular endothelial cells is increased, and this finding is a marker of disease activity. The significance of an increased expression of an endothelial anticoagulant glycoprotein in diseases characterized by pathologic intraglomerular coagulation is unknown, and requires further studies.

Fluorescent Antibody Technique↗
PubMed1992

Histochemical study of the lumbar colonic nerve supply to the internal anal sphincter and its physiological role in dogs.

The sympathetic innervation of the internal and sphincter (IAS) and its physiological role in maintaining sphincter tone were histochemically and mechanically studied in dogs anesthetized with pentobarbital sodium. Numerous catecholamine-fluorescent nerve fibers with varicosities were identified in the IAS of normal dogs. Such fibers were markedly reduced at one week and one month after resection of the hypogastric nerves (HGNs) or the lumbar colonic nerve (LCN), and disappeared after combined HGN and LCN resection. IAS tone decreased to 37.2% of baseline at 1 h after LCN resection and to 69.9% after HGN resection. It returned to the preoperative level at one week and one month after resection. The restored IAS tone was decreased again by acute transection of the previously intact HGNs or LCN. Combined LCN and HGN resection also caused a marked reduction of IAS tone (36.9%) at 1 h after the procedure, and was then restored to the preoperative level with time. The restored tone was not decreased by phentolamine administration. These findings confirmed that both the LCN and the HGN innervate the IAS and play a physiological role in the development of resting tone. The restoration of IAS tone after denervation may be due to intrinsic myogenic properties of the sphincter.

Acetylcholine↗
PubMed1992

High glucose and hyperosmolarity increase platelet-derived growth factor mRNA levels in cultured human vascular endothelial cells.

We investigated the effects of high glucose and hyperosmolality on platelet-derived growth factor (PDGF) production and PDGF-B chain mRNA levels in cultured human umbilical vein endothelial cells. Under an excess of ambient glucose (13.8 and 27.5mM) and a hyperosmolar condition (22.0mOsm/L with mannitol), PDGF concentrations in the culture medium were both significantly increased (10.3 +/- 6.0%, 36.2 +/- 7.2%, 48.5 +/- 9.0% increase respectively compared with 5.5mM glucose). Parallel to protein secretion levels, PDGF-B chain mRNA levels showed a significant increase (57.7%, 103.7%, 210.8% increase), while no change of beta-actin mRNA levels was observed. Thus, elevated PDGF released from endothelium by high glucose may play an important role in the pathogenesis of diabetic angiopathy.

Blotting, Northern↗
PubMed1992

SPECT demonstration of splenosis.

Splenosis is defined as the heterotopic autotransplantation of splenic tissue. The main cause of splenosis is splenic rupture following abdominal trauma, in which fragments of splenic tissue are seeded throughout the peritoneal cavity. Demonstration of splenosis by scintigraphy or CT imaging has been reported, but there is no previous report of simultaneous demonstration by SPECT and CT imaging. Autotransplantation of splenic tissue in the abdominal cavity forms a solid tumor-like image on CT and is difficult to differentiate from other abdominal masses. In such cases, SPECT demonstration of splenosis is very important for identification of its exact site. A case report of splenosis is presented, in which simultaneous demonstration by SPECT and CT was performed. This was confirmed at laparotomy for gastrectomy.

Abdominal Neoplasms↗
PubMed1992

Malignant progression of a mouse fibrosarcoma by host cells reactive to a foreign body (gelatin sponge).

The QR regressor tumour (QR-32), a fibrosarcoma which is unable to grow progressively in normal syngeneic C57BL/6 mice, was able to grow progressively in 13 out of 22 mice (59%) when it was subcutaneously coimplanted with gelatin sponge. We established four culture tumour lines from the resultant tumours (QRsP tumour lines). These QRsP tumour lines were able to grow progressively in mice even in the absence of gelatin sponge. The ability of QRsP tumour cells to colonise the lungs after intravenous injection and to produce high amounts of prostaglandin E2 (PGE2) during in vitro cell culture was much greater than that of parent QR-32 cells. These biological characteristics of QR-32 cells and QRsP tumour cells were found to be stable for at least 6 months when they were maintained in culture. We also observed that QR-32 cells were able to grow progressively in five out of 12 (42%) mice after coimplantation with plastic non-adherent peritoneal cells obtained from mice which had been intraperitoneally implanted with gelatin sponge. These host cells reactive to gelatin sponge increased the production of high amounts of PGE2 by QR-32 cells during 48 h coculture. Preliminary in vitro studies implicated the involvement of hydrogen peroxide and hydroxyl radical as some of the factors necessary to induce QR-32 cells to produce high amounts of PGE2 and to accelerate tumour progression.

Animals↗
PubMed1992

Ascending contraction mediated by 5-hydroxytryptamine3 receptors in canine small intestine.

We investigated the mechanism of ascending contraction induced by activation of 5-hydroxytryptamine3 (5-HT3) receptors in anesthetized dogs. Pressure-measuring balloons were inserted into a loop of extrinsically denervated jejunum. Drugs were administered via the arterial tree to the oral or the anal segment and the ensuing mechanical responses were monitored. Administration of 2-methyl-5-HT (440 pmol-44 nmol) to the anal segment caused contractions in the oral segment in a dose-dependent manner. This response was inhibited by treating the anal segment with ICS 205-930, cocaine, hexamethonium, or tetrodotoxin and by treating the oral segment with atropine or hexamethonium. The response persisted even after abolition of contraction in the anal segment by nifedipine. These results imply that activation of 5-HT3 receptors can induce an ascending contraction through an enteric excitatory pathway formed by a series of cholinergic interneurons and final cholinergic motor neurons, apart from the anal contraction.

Animals↗