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Biomedical subjects

A Hara

Publications and source records attributed to A Hara.

At least 325 records · Page 18Linked to original sources
PubMed1994

Surface structure of rabbit and human retina after enzymatic separation of inner limiting membrane.

In order to investigate the structure of the retina without the overlying inner limiting membrane (ILM), the ILM was separated from the retina in rabbit and human specimens by enzymatic digestion with matrisolve and trypsin. Human specimens were taken from the area between the optic disc and the fovea, while rabbit specimens were taken from 5 mm below the medullary ray. The rabbit specimens were immersed and digested in 0.05% trypsin, while the human specimens were immersed and digested in crude matrisolve. Digestion was carried out before fixation. The structure of the denuded retina without the overlying ILM was observed by scanning electron microscopy (SEM) following enzymatic digestion. In both the human and rabbit specimens, the ILM appeared to be a structure that was independent from the retina. The surface of the denuded retina appeared to be covered with Müller cell footplates, which appeared in cobblestone arrangement in rabbit specimens and in mosaic arrangement in human specimens. Adhesion between the ILM and the retina seemed to be maintained by a biochemical matrix that was digested by proteinases, in both rabbit and human specimens.

Aged↗
PubMed1994

Physical biochemical properties of IgM from a teleost fish.

Teleost fish are able to produce IgM class antibody, as are other vertebrates. When the teleost fish Oreochromis niloticus was immunized with bovine serum albumin (BSA), it produced antibody to BSA with an average avidity of 7.4 x 10(8)/M. Thus, dissociation of antigen-antibody complexes only occurred at conditions of < pH 2.5, > pH 11, > 4M NaI or > 4M urea, demonstrating high stability of the complex. Western blot analyses further showed the high specificity of the antibody to BSA. In contrast to mammals, when the fish was challenged with multiple protein antigens, it produced antibody only to the major component but not to others. The antibody generated to a specific antigen accounted for up to 1.1% of whole serum protein or 7.0% of whole immunoglobulin. We conclude (1) the systemic antibody response in teleost fish may be an 'all or nothing' response, which is different from that in mammals; (2) the quality (specificity and affinity) of the antibody produced is similar to that of mammals. The findings not only reveal a quite different strategy of immune response in fish, but also raise the possibility of technical application.

Animals↗
PubMed1993

Chemopreventive effects of dietary D,L-alpha-difluoromethylornithine, an ornithine decarboxylase inhibitor, on initiation and postinitiation stages of diethylnitrosamine-induced rat hepatocarcinogenesis.

The modifying effects of dietary administration of D,L-alpha-difluoromethylornithine (DFMO) during initiation or postinitiation phase on the hepatocarcinogenesis initiated by diethylnitrosamine (DEN) were investigated in male F344 rats. A total of 129 animals were divided into seven groups. Groups 1-5 were given the drinking water containing 40 ppm DEN for 5 weeks, starting at 7 weeks of age. Groups 2 and 3 were fed the diets mixed with 500 and 1000 ppm DFMO, respectively, for 7 weeks, starting at 6 weeks of age. Groups 4 and 5 were given the diets containing 500 and 1000 ppm DFMO, respectively, starting 1 week after DEN exposure and maintained on these diets until the end of the study (Week 32). Rats in group 6 were fed the DFMO diet (1000 ppm) alone during the experiment. Group 7 served as an untreated control. At the end of the study, the incidences of liver cell foci (resistant iron accumulation or positive for glutathione S-transferase placental form) and hepatocellular neoplasms along with polyamine levels in the liver were measured. Also, morphometric analysis of silver-stained nucleolar organizer regions proteins as cell proliferation activity in liver cells was performed. The mean incidences and areas of foci in rats given DEN and DFMO in groups 2-5 were significantly lower than those of group 1 (P < 0.01). The frequencies of liver cell tumors in group 3 (50%), 4 (24%), and 5 (45%) were significantly reduced compared to that of group 1 (100%) (P < 0.01). The multiplicities of neoplasms in group 2 (1.15/rat), 3 (0.65/rat), 4 (0.35/rat), and 5 (0.95/rat) were significantly smaller than that of group 1 (3.34/rat) (P < 0.001). Although the polyamine levels of liver tissues among the groups showed no clear differences among the groups, the number and area of silver-stained nucleolar organizer regions proteins/nucleus in rats given DEN and DFMO (groups 2-5) were significantly lower than those of group 1. These results indicate that the feeding of DFMO during the initiation or postinitiation stage clearly inhibited DEN-induced rat hepatocarcinogenesis and that such inhibition may be due to alteration in cell proliferation activity caused by DFMO.

Animals↗
PubMed1993

Cloning and sequence analysis of a cDNA encoding tetrameric carbonyl reductase of pig lung.

A cDNA for tetrameric carbonyl reductase was cloned from a pig lung cDNA library. The cDNA had an open reading frame encoding a protein of 244 amino acid residues with a predicted monomer molecular weight of 25,985. The authenticity of the cDNA was confirmed by a perfect match of 80 amino acids determined from sequencing of amino-terminus, carboxy-terminus and internal fragments of the purified enzyme. The deduced sequence of the carbonyl reductase shows a similarity to those of the short-chain alcohol dehydrogenase superfamily proteins; notably it had an extensive homology (85% identical residues) with a putative gene product of murine adipocyte.

Alcohol Oxidoreductases↗
PubMed1993

Abnormal excretion of urinary phospholipids and sulfatide in patients with mitochondrial encephalomyopathies.

We found that patients with mitochondrial encephalomyopathies excreted urinary phosphatidylethanolamine, cardiolipin, and phosphatidylserine most likely derived from mitochondria and sulfatide which is specific to myelin or the kidney. It is of interest that four patients with myoclonus epilepsy with ragged-red fibers and one patient with chronic progressive external ophthalmoplegia all showed qualitatively similar abnormal excretion of such urinary lipids. It is conceivable that the urinary acidic phospholipids reflect abnormalities in the mitochondrial phospholipids, which are very important for mitochondrial enzymatic activities.

Adolescent↗
PubMed1993

Chemoprevention of oral carcinogenesis by DL-alpha-difluoromethylornithine, an ornithine decarboxylase inhibitor: dose-dependent reduction in 4-nitroquinoline 1-oxide-induced tongue neoplasms in rats.

The modifying effect of three doses of DL-alpha-difluoromethylornithine (DFMO) given p.o. during the post-initiation phase of tongue carcinogenesis initiated by 4-nitroquinoline 1-oxide (4-NQO) was studied in male ACI/N rats. Animals were given 4-NQO at 20 ppm for 8 weeks in the drinking water to induce tongue neoplasms. One week after the stop of 4-NQO treatment, rats were transferred to the drinking water containing DFMO at concentrations of 100, 1000, and 2000 ppm for 25 weeks. The other groups consisted of rats given 2000 ppm DFMO alone or untreated rats. Thirty-four weeks after the start of the experiment, all animals were necropsied, and the incidences of neoplasms and preneoplastic lesions in the tongue, polyamine levels in the bloods and tongue tissues, and cell proliferation estimated by the number and area of silver-stained nucleolar organizer regions in the tongue epithelium were compared among the groups. Feeding of DFMO at all doses significantly inhibited the incidence of tongue neoplasms compared to the group given 4-NQO alone. DFMO at levels of 1000 and 2000 ppm significantly reduced the incidence of preneoplastic lesions of the tongue. Results analyzed by the linear regression method suggested a dose-dependent inhibition in the incidences of neoplastic and preneoplastic lesions of the tongue with increasing levels of DFMO. Increased levels in polyamines in the blood and tongue tissue were significantly suppressed by the treatment of DFMO. Also, silver-stained nucleolar organizer region indices were significantly reduced by the DFMO exposure. These results indicate that increasing levels of DFMO in the drinking water inhibited 4-NQO-induced tongue carcinogenesis in a dose-dependent manner and such inhibition was related to reduction in the polyamine levels of blood and tissue and decrease in the cell proliferation.

4-Nitroquinoline-1-oxide↗
PubMed1993

Monkey 3-deoxyglucosone reductase: tissue distribution and purification of three multiple forms of the kidney enzyme that are identical with dihydrodiol dehydrogenase, aldehyde reductase, and aldose reductase.

3-Deoxyglucosone (3DG) is a reactive intermediate in the glucose-mediated cross-linking of proteins. An enzyme catalyzing the reduction of 3DG is thought to prevent the damage to protein by the formation of 3DG. The NADPH-dependent enzyme activity was detected in the extracts of various monkey tissues, among which kidney exhibited the highest specific activity. One dimeric enzyme with subunit M(r) of 39,000 and two monomeric enzymes with M(r) of 38,000 and 34,000 were purified from monkey kidney. The dimeric enzyme exhibited high dihydrodiol dehydrogenase activity and was immunochemically identical to dimeric dihydrodiol dehydrogenase of monkey kidney. The two monomeric enzymes exhibited aldehyde reductase activity, but were clearly distinct from each other in substrate specificity, inhibitor sensitivity, and effect of sulfate ions. One enzyme was immunologically cross-reacted with human liver aldehyde reductase, whereas sequence data of digested peptides from the other enzyme revealed > 97% identity with human placental aldose reductase. Comparison of kinetic constants among the monkey kidney enzymes and aldoketo reductases from several mammalian tissues indicated that dimeric dihydrodiol dehydrogenase and aldose reductase exhibited higher catalytic efficiency for 3DG than did aldehyde reductase, carbonyl reductase, and monomeric dihydrodiol dehydrogenase.

Alcohol Oxidoreductases↗
PubMed1993

A monoclonal antibody (H227) recognizing a new epitope of 4F2 molecular complex associated with T cell activation.

We developed and characterized a monoclonal antibody (mAb), H227, recognizing a new epitope of human 4F2 molecular complex whose roles remain to be identified. Both staining patterns and molecular sizes recognized by H227 mAb were the same to those of 4F2 mAb. Thus, both H227 and 4F2 mAbs were reactive to monocytes, thymocytes, and activated lymphocytes and immunoprecipitated the 125-kDa molecular weight membrane protein under nonreducing conditions and 85-kDa heavy-chain and 40-kDa light-chain proteins under reducing conditions. These two mAbs immunoprecipitated only the 85-kDa heavy-chain protein when the cell lysate was initially treated with dithiothreitol. Sequential immunoprecipitation proved their cross-reactivity. Both the mAbs inhibited phytohemagglutinin- or concanavalin A-induced proliferation of peripheral blood mononuclear cells (PBMC). In contrast to these similarities, the pretreatment of cells with one mAb failed to block the reactivity to the other, suggesting that their epitopes were different from each other. Furthermore, only H227 mAb augmented phorbol myristate acetate (PMA)-induced PBMC proliferation in association with increase in interleukin 2 receptor expression. In summary, H227 mAb recognizes a new epitope of 4F2 heavy chain that might be involved in the PMA-induced T cell activation pathway and therefore shall be a useful tool for understanding the roles of the 4F2 molecular complex.

Antibodies, Monoclonal↗
PubMed1993

A novel antigen (H47 Ag) on human lymphocytes involved in T cell activation.

Surface molecules involved in human T cell activation were investigated using a newly developed monoclonal antibody (H47 mAb). H47 antigen (Ag) recognized by H47 mAb was expressed on approximately 10% of resting T cells (mostly CD4-CD8+), 30% of phorbol 12-myristate 13-acetate (PMA)-activated T cells (both CD4+CD8- and CD4-CD8+), and most NK, B cells, and monocytes in the peripheral blood mononuclear cells (PBMC). H47 mAb respectively immunoprecipitated a 100 or 120-kD molecular weight (MW) membrane protein of T cells and monocytes under nonreducing or reducing conditions, suggesting that H47 Ag consists of a single polypeptide that has intramolecular disulfide bonds. H47 mAb significantly enhanced PMA-induced proliferation of PBMC in a monocyte-independent fashion. H47 mAb, however, failed to enhance T cell proliferation induced by anti-CD3 mAb, anti-CD2 mAb, or phytohemagglutinin (PHA). H47 mAb also enhanced PMA-induced interleukin-2 receptor (IL-2R) expression and IL-2 synthesis, but did not induce a change in intracellular free calcium ([Ca2+]i) of T cells. These results suggest that H47 Ag is a new membrane molecule involved in PMA-induced T cell activation.

Animals↗
PubMed1993

Expression of the placental form of glutathione S-transferase in pediatric gliomas.

Expression of the human placental form of glutathione S-transferase (GST-pi) in pediatric gliomas, consisting of three pilocytic astrocytomas (grade 1), two fibrillary astrocytomas (grade 2), three anaplastic astrocytomas (grade 3), and one glioblastoma multiforme (grade 4), were investigated by immunohistochemical methods. Western blot analysis for GST-pi using proteins extracted from formalin-fixed and paraffin-embedded glioma specimens was performed and compared with the results of immunohistochemistry. Both the immunohistochemical examination and the Western blot analysis of pediatric gliomas revealed that malignant gliomas such as anaplastic astrocytoma and glioblastoma had strong expression of GST-pi while benign gliomas showed weak GST-pi expression.

Adolescent↗
PubMed1993

Histochemistry with Helix pomatia agglutinin in human germ cell tumors: detection of nongerminomatous components and correlation between HPA reactivity and radiosensitivity in germinomas.

Binding sites of Helix pomatia agglutinin (HPA) were examined in 32 patients with intracranial human germ cell tumors. HPA reactivity was found in vascular endothelial cells and erythrocytes of patients with blood type A or AB. HPA-positive neoplastic cells were seen in one yolk sac carcinoma in a patient with blood group A, and in embryonal carcinomas and teratomas irrespective of blood group type. Although in 10 out of 18 germinomas neoplastic cells were totally negative for HPA, another 8 germinomas showed HPA-positive neoplastic cells which were distributed sporadically or in an area and independent of blood group types. HPA-negative germinoma patients showed a very good response to radiotherapy, whereas 4 out of 8 HPA-positive tumors showed poor radiosensitivity, with a residual lesion seen on computed tomography even after the total radiation dose of 40-50 Gy. These findings suggest that HPA-positive neoplastic cells in germinomas indicate components of differentiation of non-germinomatous germ cells. HPA-positive germinomas might be less radiosensitive than HPA-negative germinomas.

ABO Blood-Group System↗
PubMed1993

Identification of placental form of glutathione S-transferase in ACNU-resistant murine glioma cell lines.

Expression of the placental form of glutathione S-transferase (GST-P) in 1-(4-amino-2-methyl-5-pyrimidinyl) methyl-3-(2-chloro-ethyl)-3-nitrosourea hydrochloride (ACNU)-sensitive 9L and C6 glioma cells, and ACNU-resistant 9L (9LR) and C6 (C6R) glioma cells was investigated by Northern blot analysis for GST-P mRNA and Western blot analysis for GST-P protein. The sensitivity of 9L, 9LR, C6 and C6R cell lines to ACNU was evaluated by microculture tetrazolium assay. Localization of GSTP-P protein in these cell lines was investigated by immunocytochemical method. Expression level of GST-P mRNA in 9LR cells was 3 times that of 9L cells and the level of GST-P protein in 9LR cells was 1.7 times that of 9L cells. On the contrary, the amount of GST-P mRNA of C6R cells was 1.3-fold larger than C6 cells and that of GST-P protein of C6R cells was 1.3-fold larger than C6 cells. Immunocytochemical investigation revealed that 9LR cells had stronger expression of GST-P in their cytoplasm than 9L cells. Expression of GST-P in both C6R and C6 cells was less than 9L and 9LR cells, and the amount was similar to each other. The present study suggests that GST-P may play an important role in detoxification of anti-cancer drugs in some glioma cells.

Animals↗
PubMed1993

Immunoblot analysis of the placental form of glutathione S-transferase in protein extracted from paraffin-embedded human glioma tissue.

Protein extracted from conventional formalin-fixed and paraffin-embedded tissue sections of human gliomas was examined for immunoblot analysis using antibody against the placental form of glutathione S-transferase (GST-pi). Four benign astrocytomas, five anaplastic astrocytomas and four glioblastomas were used in this study. The preliminary study demonstrated that immunoreactivity of GST-pi was well preserved in normal brain tissue and normal term placenta fixed in acetone, formalin or buffered formalin (pH 7.4). GST-pi in gliomas fixed in formalin also had a good immunoreactivity and showed clear bands on nitrocellulose membranes processed by the method of Western blotting using anti-GST-pi antibody. The results of immunoblot analysis for GST-pi indicate that the intensity of immunoreactivity of benign astrocytoma, anaplastic astrocytoma and glioblastoma increases with the advance of malignancy of these neoplasms. Western blot analysis for GST-pi can be performed using protein extracted from formalin-fixed and paraffin-embedded tissue sections, and the immunoreactive bands can be analyzed quantitatively by densitometric scanning.

Blotting, Western↗
PubMed1993

Central neurocytoma: proliferative assessment by nucleolar organizer region staining.

Proliferative potential of four cases of central neurocytoma were assessed by a silver colloid staining technique for argyrophilic protein associated with nucleolar organizer regions (AgNORs). All but one tumor had an Ag-NOR score of less than 2 and were regarded as a benign entity. However, one tumor tissue from a patient suffering from a recurrent central neurocytoma after 13 years from the first operation possessed a 2.06 AgNOR score, which is not significantly different from others. It is considered that central neurocytoma is an essentially benign neoplasm, even though the tumor is recurrent. The present study revealed the usefulness of AgNOR staining for a retrospective assessment of the proliferative potential of central neurocytomas.

Adult↗
PubMed1993

Pharmacokinetics of furosemide in endolymph.

To investigate the pharmacokinetics of organic anions in the endolymph of the guinea pig, 100 mg/kg furosemide, an organic anion, was intravenously given to measure the concentration in the cochlear endolymph by high-performance liquid chromatography with fluorescence detection. In the endolymph, the concentration of the furosemide increased slowly for 1 hr to 1.6 micrograms/ml and gradually declined thereafter. Pretreatment with 200 mg/kg probenecid, an anion transport inhibitor, had no effect on the furosemide elimination in the endolymph except on the concentration at 2 hr. This was contrary to the drastic change observed in the perilymph of the scala tympani by the same pretreatment. Analogous to the effect in the endolymph, probenecid showed no change in the concentration of the serum, while a pronounced gradient of furosemide concentration existed between them. The present results suggest that the furosemide passively transfers from blood to the endolymph at a relatively low penetrability.

Animals↗
PubMed1993

Intrusion of an incisor tooth into the contralateral frontal sinus following trauma.

Although intrusions of glass fragments into the frontal sinuses are not uncommon in traffic accidents, a case with a tooth in the frontal sinus has never been reported. We report a patient with traumatic inclusion of an incisor tooth in the contralateral frontal sinus. Radiographic investigations demonstrated the tooth in the frontal sinus though no skin damage was recognized on the upper face. The usefulness of CT scan in localizing the missing tooth after facial trauma and its route of entry into the contralateral frontal sinus is discussed.

Accidents, Traffic↗