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Biomedical subjects

H Imai

Publications and source records attributed to H Imai.

At least 415 records · Page 23Linked to original sources
PubMed1989

Coordinate accumulation of troponin subunits in chicken breast muscle.

The accumulation of troponin subunits in developing chicken breast muscle was determined by two-dimensional gel electrophoresis and an image analyzing system. Many troponin T isoforms, including those hidden behind creatine kinase, were detected on the two-dimensional pattern by the addition of 6 M urea in the second dimension. These troponin T isoforms were classified into four types by developmental order, isoelectric point, and molecular weight: leg-muscle type (L), neonatal breast-muscle type (BN), young chicken breast-muscle type (BC), and adult breast-muscle type (BA). The L-, BN-, and BC-type troponin Ts were transiently expressed at specific developmental stages. Quantitative analysis of two-dimensional patterns of troponin subunits including troponin I and troponin C showed moderate coordination in accumulation among the three subunits throughout postnatal development, when the total amount of all isoforms of troponin T was taken into account.

Animals↗
PubMed1989

Mesangiolytic glomerulonephritis associated with Takatsuki's syndrome: an analysis of five renal biopsy specimens.

Renal biopsy specimens from five patients with Takatsuki's syndrome were studied. Proteinuria and hematuria were modestly positive in four cases and three cases, respectively. One case demonstrated early azotemia, while four cases revealed normal serum creatinine levels. All cases displayed glomerular enlargement and lobulation, mesangial cell proliferation, and double contour structure, simulating membranoproliferative glomerulonephritis. It is noteworthy that mesangial loosening was also detected in the renal biopsy specimens of this study. This change was present diffuse-globally in the well-developed cases and focal-globally or segmentally in the developing cases. In addition, various morphologic expressions were observed, ie, microaneurysms congested with RBCs, tentatively termed mesangial hyaline thrombi, nodule-like lesions, and tiny to small-sized mesangiolytic lesions. Since all these features could be explained by low-grade mesangiolysis, the renal alteration associated with this syndrome was termed mesangiolytic glomerulonephritis. Humoral factor(s) also toxic to the mesangium were implicated.

Adult↗
PubMed1989

Anti-histone autoantibodies in ddY mice, an animal model for spontaneous IgA nephritis.

The ddY mice are known to develop spontaneous glomerulonephritis resembling human IgA nephritis after 40 weeks of age. A sharp rise of circulating polyclonal IgG and IgA is also observed at this stage. Since these overproduced immunoglobulins seem to be related to the development of murine glomerulopathy, antigen-antibody interactions between renal tissue proteins and serum immunoglobulins were analyzed by Western blotting in ddY mice before and after 40 weeks of age. Serum IgG at 50 weeks reacted with an 18-kDa renal tissue protein which was identified as histone H3, as well as with histone H1. Renal histones were extracted along with IgG from the murine kidney at 50 weeks in a high salt soluble fraction. Serial studies of anti-histone antibodies by enzyme-linked immunosorbent assay showed that IgG class antibodies markedly increased after 40 weeks of age. IgA class antibodies mildly increased after 56 weeks of age. Anti-DNA antibodies were not detected. These results demonstrate that ddY mice also develop mainly IgG class and partly IgA class anti-histone autoantibody after 40 weeks of age, and that histone-anti-histone complexes may contribute to the development of murine glomerulopathy. Although anti-histone antibodies have been reported in lupus mice, ddY mice differ from these mice in that no anti-DNA antibodies develop.

Animals↗
PubMed1989

Comparison of anamnestic history, alcohol intake and smoking, nutritional status, and liver dysfunction between thorotrast patients who developed primary liver cancer and those who did not.

In order to clarify the differences in past history, nutritional condition and, consumption of alcohol and tobacco, and liver dysfunction between the thorotrast patients who developed primary liver cancer and those who did not, 103 persons who had no primary liver cancer in January 1980 were studied. All subjects were military men who had undergone angiography with thorotrast between 1943 and 1946. Twenty persons developed hepatocellular carcinoma and 16 developed intrahepatic bile duct carcinoma by April 1987, whereas 67 are still alive without any cancer. There was no difference in age or period after thorotrast infusion between those two groups of patients in January 1980. A difference in history of hepatitis and/or jaundice and presence of hepatic dysfunction was found between the subjects who developed primary liver cancers and those who did not. These findings suggest that an anamnestic history of hepatitis and liver dysfunction are risks for development of thorotrast-induced liver cancer. On the basis of the above findings, early detection of liver dysfunction offers a possibility of early diagnosis of primary liver cancer.

Aged↗
PubMed1989

Enhanced ATPase activity in liver cell nuclei induced by administration of mitomycin C to rats.

Intraperitoneal administration of mitomycin C (40 micrograms/100 g body weight) to male Wistar rats increased the ATPase activity in hypotonic extracts of liver cell nuclei for 4 days after injection. Partially purified ATPase, obtained by the DEAE-cellulose column chromatography of these extracts, showed a 14 times higher specific activity than that found in normal rat liver nuclei. The enzymatic activity was strongly enhanced by the addition of polynucleotides, especially poly A and poly I, to the assay mixture, but was inhibited by GTP, a chelating agent, heparin and thiol-group inhibitors. Quercetin and oligomycin were less effective, and ouabain showed no inhibitory effect. Mg2+ ions were essential, but neither Ca2+, Na+ nor K+ ions were required for the manifestation of the activity. These characteristic properties of the enzyme are similar to those of a nucleoside triphosphatase found in the nuclear matrix and envelope, suggesting that some energy-providing mechanisms involved in the repair processes of DNA damage or cellular injury are induced by mitomycin C administration.

Adenosine Diphosphate↗
PubMed1989

Multicentric astrocytomas of the optic chiasm, brain stem and spinal cord.

Autopsy was performed on a 52-year-old man with a 20-year history of neurological symptoms. At autopsy, both a brain stem tumor and a spinal cord tumor were found. These showed the features of pilocytic astrocytoma histologically. A pilocytic astrocytoma was also found in the optic chiasm upon microscopical examination. These three tumors were thought to be multicentric astrocytomas, because there was no continuity among them and no evidence of dissemination or metastasis by any pathway. From a review of the literature, the present case is considered to be an exceedingly rare one because of the multicentric sites of occurrence.

Adult↗
PubMed1989

The relationship between connective tissue and its microvasculature in the healthy dog gingiva.

The morphological consistency of subepithelial connective tissue and its vascular architecture was studied in the healthy gingiva of adult mongrel dogs. Corrosion-cast specimens of the vasculature and specimens of well-separated connective tissue from the lamina propria were observed by SEM. Specimens injected with india ink also were examined employing light microscopy. Summarizing the results: 1) Beneath the buccal gingival epithelium, short conical papillae were seen in the subepithelial connective tissue. The capillary structure throughout this region was basically of the loop type, the overall appearance of which replicated the papillae. The papilla disappeared at the muco-gingival junction, so that after the transition to the alveolar mucosa, no papillary formation was observed. The vasculature had transformed from loop to network structure. 2) Beneath the sulcular gingival epithelium, the subepithelial connective tissue displayed a smooth concavity with no papillae. In this region, the capillaries formed a flat, dense network in accordance with the morphology of the connective tissue. The capillary network suddenly disappeared at the terminal edge of the inner epithelium. The vessels of the lamina propria located immediately beneath the network reduced their lumina at the margin and formed the plexus of the periodontium, displaying a rather open network.

Acrylic Resins↗
PubMed1989

Carbamazepine-induced granulomatous necrotizing angiitis with acute renal failure.

A 42-year-old male treated with carbamazepine developed a skin eruption in the trunk, followed by acute renal failure. Laboratory data revealed leukocytosis (15,700/mm3) with eosinophilia (37%). A renal biopsy disclosed granulomatous necrotizing angiitis that differed from classic periateritis nodosa and hypersensitivity angiitis. All drugs were discontinued immediately, and there was a gradual improvement of the renal function. A carefully performed provocation test using carbamazepine was positive. We made a diagnosis of carbamazepine-induced granulomatous necrotizing angiitis. Only 6 cases of drug-induced granulomatous angiitis have been reported prior to the present case. Drug-induced granulomatous angiitis is often fatal. The present report suggests the importance of making a diagnosis quickly, and providing adequate treatment in order to prevent a fatal course.

Acute Kidney Injury↗
PubMed1989

Nuclear transplantation of male primordial germ cells in the mouse.

We examined the developmental ability of enucleated eggs receiving embryonic nuclei and male primordial germ cells (PGCs) in the mouse. Reconstituted eggs developed into the blastocyst stage only when an earlier 2-cell nucleus was transplanted (36%) but very rarely if the donor nucleus was derived from a later 2-cell, 8-cell, or inner cell mass of a blastocyst (0-3%). 54-100%, 11-67%, 6-43% and 6-20% of enucleated eggs receiving male PGCs developed to 2-cell, 4-cell, 8-cell and blastocyst stage, respectively, in culture. The overall success rate when taking into account the total number of attempts at introducing germ cells was actually 0-6%. Live fetuses were not obtained after transfer of reconstituted eggs to recipients, although implantation sites were observed. The developmental ability of reconstituted eggs in relation to embryonic genome activation and genomic imprinting is discussed.

Animals↗
PubMed1989

Serotonin neurons and their physiological roles.

Anatomical and functional aspects of serotonin (5HT) neurons in the central nervous system are described with special reference to their neurohumoral function. The central 5HT neurons show morphological features characteristics of the modulating nervous system: a small number of cell bodies and extremely broad innervation. These may play some part in EEG arousal through the divergent projection. Being most active during the waking state, the 5HT neurons are responsible for the onset of sleep. 5HT released during waking may initiate the humoral, as well as neuronal mechanisms leading to sleep. Although the 5HT dependent hypogenic structure is highly localized in the anterior hypothalamus, the effect seems to be due to neurohumoral action of 5HT. The neurohumoral function of the 5HT neuron is suggested by the ultrastructure of 5HT terminals almost devoid of a synaptic structure (less than 10%). Intraventricular 5HT fibers also represent a substrate supporting the neurohumoral function. A strong activity of monoamine oxidase (MAO) is found in intercellular spaces in the arcuate nucleus region of the hypothalamus, where a high 5HT immunoreactivity is seen in the young rat before MAO activity appears. It is likely that 5HT liberated in the cerebrospinal fluid is drained through these intercellular channels.

Animals↗
PubMed1989

Periosteal microvasculature in the dog alveolar process.

Most periodontal surgery has been performed on the basis of the regenerating capacity of the periosteum. Recently it has been pointed out that the blood supply is important to the osteogenic and fibrogenic activity of the periosteum. The purpose of the present study was three-dimensional observation of blood vessels distributed within the gingival periosteum and the periosteum beneath the alveolar mucosa of adult mongrel dogs. Corrosion cast specimens of vessels were observed from three directions: mucosal side, bone side, and horizontal cut surface. It was revealed that the plexus distributed in the periosteum of the gingiva formed a coarse network structure, which consisted mainly of arterioles and venules. In contrast, in the periosteum of the alveolar mucosa, a dense network structure consisting of arterioles, capillaries, and venules formed a vascular bed. Thus, the mucogingival junction was easily located even in the plexus of periosteum which was distributed beneath the gingiva and the alveolar mucosa, suggesting that the difference in tissue specificity was reflected in the plexus of the periosteum.

Alveolar Process↗
PubMed1989

[Study of ultrasonography applied to dental diagnosis. Examination of gingival morphology including epulis in relation to root surface].

Examination of gingival morphology was conducted using ultrasonic imaging equipment in a 57-year-old female with epulis. The ultrasonogram showed external gingival morphology including epulis and root surface caries which was difficult to detect because of masking by gingival enlargement. It appears that ultrasonograms are useful not only in examining gingival morphology but also in detecting changes in root surfaces hidden by the gingiva.

Female↗
PubMed1989

Hatomamicin (YL-0358M-A), a new alkaloid antibiotic: fermentation, isolation, structure, and biological properties.

Hatomamicin, a new alkaloid antibiotic, was isolated from the culture filtrate of a strain of Saccharopolyspora. The antibiotic was extracted with EtOAc and purified by silica gel column chromatography. The free alkaloid was obtained as pale yellowish prisms from CH3CN solution. It exhibits antimicrobial activity against Gram-positive organisms. The apparent molecular formula of hatomamicin was determined to be C22H31NO5. The structure has been established by a combination of spectroscopic and X-ray crystallographic studies.

Alkaloids↗