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Biomedical subjects

M Sano

Publications and source records attributed to M Sano.

At least 379 records · Page 21Linked to original sources
PubMed1992

Enhancing effects of harman and norharman on induction of preneoplastic and neoplastic kidney lesions in rats initiated with N-ethyl-N-hydroxyethylnitrosamine.

The modifying potential of two nephrotoxic agents, harman and norharman, on N-ethyl-N-hydroxyethylnitrosamine (EHEN)-induced renal and hepatic carcinogenesis was investigated in male F344/DuCrj rats. Animals were given 0.1% EHEN in their drinking water for the first 2 weeks as an initiator. Subsequently, starting 3 weeks from the commencement, they were fed diet containing these compounds at concentrations of 1000, 500 or 0 ppm until week 26, and then killed for light microscopic examination. The mean numbers of renal tubular cell hyperplasias/cm2 and those of tumors/cm2 in rats given harman and norharman at 1000 ppm after initiation, but not at 500 ppm, were significantly increased as compared to the control values. However, neither compound modified liver carcinogenesis. It is concluded that harman and norharman show enhancing effects on rat kidney carcinogenesis, when ingested at dose levels which cause renal tubular damage.

Animals↗
PubMed1992

Synergism of environmental carcinogens and promoters on bladder cancer development initiated by N-butyl-N-(4-hydroxybutyl)nitrosamine in F344 rats.

Synergistic or additive effects of combined treatments with carcinogens or promoters on N-butyl-N-(4-hydroxybutyl)nitrosamine (BBN)-initiated rat bladder carcinogenesis were examined. Male F344 rats were given BBN as an initiator followed by low doses of 3 sodium salts (sodium bicarbonate, sodium L-ascorbate and sodium citrate) and/or 3 antioxidants (butylated hydroxyanisole, butylated hydroxytoluene and tertiary butylhydroxyquinone). Combined treatments with 3 sodium salts or 3 antioxidants, and especially all 6 chemicals together promoted bladder carcinogenesis. In addition, these combined treatments were associated with increased DNA synthesis of the bladder epithelium. Combined administration of the carcinogens, o-anisidine, p-cresidine, and 4-chloro-o-phenylenediamine at low doses also enhanced BBN-initiated bladder carcinogenesis. These results indicate that environmental carcinogens or promoters can exert synergistic or additive actions on bladder cancer induction.

Animals↗
PubMed1992

Immunohistochemical localization of calmodulin in the human testis [corrected].

The localization of calmodulin in the normal human testis was studied by the indirect immunoperoxidase method. Three different types of fixative were used: phosphate-buffered formalin, Bouin's solution or Carnoy's solution. Immunoreactivity specific for calmodulin was not detectable in the testis fixed in Carnoy's solution. The specimens fixed in phosphate-buffered formalin and in Bouin's solution were stained. The immunostaining for calmodulin was observed in pachytene spermatocytes, secondary spermatocytes and round spermatids but not in spermatogonia, or in pre-leptotene, leptotene and zygotene spermatocytes, elongated spermatids, spermatozoa or Leydig cells. Sertoli cells were not stained or were stained slightly. Among pachytene spermatocytes, the cells at the early stage were barely stained but those at the middle and late stages were slightly and intensely stained, respectively. The present report provides the first confirmation of the localization of calmodulin in the human testis.

Adult↗
PubMed1992

Chromatographic resolution and characterization of a nerve growth factor-dependent kinase that phosphorylates microtubule-associated proteins 1 and 2 in PC12 cells.

When the supernatant fractions from extracts of control and nerve growth factor (NGF)- or dibutyryl cyclic AMP-treated PC12D cells were applied to DEAE-Sepharose columns and proteins were eluted with a gradient of NaCl, three separate peaks of kinase activity that phosphorylated microtubule-associated proteins (MAPs) were recovered. Enhancement of the kinase activity in peak 1 was noted in the case of dibutyryl cyclic AMP-treated cells. In contrast, the kinase activity in the third peak was markedly elevated, in terms of the ability to phosphorylate MAP1 and MAP2, in the case of the extract from NGF-treated cells. This activity was designated previously as NGF-dependent MAP kinase. The apparent molecular mass of the active kinase was 45-50 kDa. The apparent Km value was 35 microM for ATP with either MAP1 or MAP2 as substrate. When the kinase activity in the fractions from the DEAE-Sepharose column was assayed in the presence of Mn2+ instead of Mg2+, another NGF-stimulated kinase activity was detected in the fractions eluted by a lower concentration of NaCl than that which eluted the Mg(2+)-activated kinase. Other growth factors, namely, epidermal growth factor and basic fibroblast growth factor, also stimulated the activity of NGF-dependent MAP kinase. Possible involvement of the kinase in the outgrowth of neurites has been suggested. The NGF-induced activation of NGF-dependent MAP kinase was blocked by the presence of K-252a. In contrast, the activation of NGF-dependent MAP kinase by basic fibroblast growth factor and by epidermal growth factor was not blocked, but actually stimulated by K-252a, a result that correlates well with the analogous actions of the drug on the outgrowth of neurites that is induced by these growth factors. The latter observation strengthens the possibility of a close relationship between the outgrowth of neurites and the activation of NGF-dependent MAP kinase.

Animals↗
PubMed1992

Activation of microtubule-associated protein kinase in PC12D cells in response to both fibroblast growth factor and epidermal growth factor and concomitant stimulation of the outgrowth of neurites.

When PC12D cells, a subline of PC12 cells, were cultured with nerve growth factor (NGF), outgrowth of neurites was promoted even when RNA synthesis was blocked. This property of PC12D cells may enable us to resolve the mechanism of the outgrowth of neurites that is induced in a transcription-independent manner. The outgrowth of neurites from PC12D cells was also stimulated in response to fibroblast growth factor (FGF) and was slightly stimulated in response to epidermal growth factor (EGF). The brief exposure of intact PC12D cells not only to NGF but also to FGF or to EGF stimulated a protein kinase activity in extracts of such cells that catalyzed phosphorylation of microtubule-associated protein 1 (MAP-1) and MAP-2 in vitro. Similar dose-response relationships for the effects of NGF and of FGF on the activation of the kinase and on the outgrowth of neurites were observed. The effects of combinations of NGF and GFG or EGF were not additive in terms of either the outgrowth of neurites or the increase in the kinase activity. Treatment of cells with phorbol 12-myristate 13-acetate (PMA) also stimulated the kinase activity that phosphorylated MAPs in vitro. However, the level of the enzymatic activity that resulted from the combined treatment of cells with PMA and NGF was additive, as is the case with dibutyryl cyclic AMP and NGF. These findings suggest that NGF, FGF, and EGF may stimulate the activity of the same MAP kinase.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Dose-dependent renal tubular toxicity of harman and norharman in male F344 rats.

The renal toxicity of harman and norharman, administered for 2 or 4 weeks at dietary levels of 1,000, 500, or 0 parts per million (ppm), was investigated in 6-week-old male F344/DuCrj rats. Although rats fed 1,000 ppm harman or norharman, but not the 500 ppm level, demonstrated marked body weight retardation from 1 week to termination, no mortalities occurred. Marked elevation of water consumption was evident in rats given harman or norharman at 1,000 ppm, but not at 500 ppm, together with large increases in urine of low specific gravity. Urinary lysosomal enzymes (N-acetyl-beta-D-glucosaminidase, NAG, and lactate dehydrogenase, LDH) and sugar levels were increased, and the brush border enzymes (gamma-glutamyl transpeptidase, GGT, and alkaline phosphatase, ALP) decreased. Furthermore, serum biochemistry revealed clear elevation of parameters indicating renal toxicity in these rats. Histopathologically, rats fed 1,000 ppm harman or norharman, but not 500 ppm, demonstrated focal toxic renal degenerative/necrotic and regenerative lesions in proximal, distal, and collecting tubules. These changes were associated with a clearly increased labeling index (LI) of the nuclei of renal tubular epithelial cells on immunohistochemical staining for 5-bromo-2'-deoxyuridine (BrdU). Chemical specific crystal formation within tubular lumina was evident in rats fed 1,000 ppm, but not 500 ppm, this being considered the cause of the renal tubular lesions. It was concluded that harman and norharman exert renal toxicity at the dietary level of 1,000 ppm, but not 500 ppm, in male F344 rats.

Acetylglucosamine↗
PubMed1992

Muscle acetylcholine receptors complexed with autologous IgG reflect seropositivity but not necessarily in vivo binding.

The diagnosis of acquired myasthenia gravis (MG) in apparently seronegative individuals is aided by finding immunoglobulin complexed to acetylcholine receptors (AChR) and a reduction in the number of binding sites for alpha-bungarotoxin (alpha-BTx) in nerve-muscle biopsies. In this study, we found that anti-AChR antibodies in extracellular fluids can complex with cytoplasmic epitopes of AChR in the process of muscle extraction. When normal muscle was briefly exposed to antibodies (greater than or equal to 0.3 nmol/l) in the initial step of tissue homogenization (before detergent extraction), membranous AChR became complexed with IgG. This was so even with a nonmyasthenogenic monoclonal antibody specific for the alpha-subunit's presumptive cytoplasmic segment 366-389. We also found that antibodies reactive with AChR's alpha-BTx binding region can significantly lower apparent yields of alpha-BTx binding sites extracted from muscle. Thus, the finding of IgG complexed to AChR extracted from biopsied muscle does not necessarily reflect in vivo binding but, nevertheless, is a sensitive indicator of AChR seropositivity in patients suspected to have MG.

Animals↗
PubMed1992

Dementia after stroke: baseline frequency, risks, and clinical features in a hospitalized cohort.

We determined the frequency of dementia in a cohort of 251 patients aged greater than or equal to 60 years hospitalized with acute ischemic stroke, based on examinations performed 3 months after stroke onset. Using modified DSM-III-R criteria, we found dementia in 66 patients (26.3%). Diagnostic agreement among raters was excellent (kappa = 0.96). In a control sample of 249 stroke-free subjects recruited from the community and matched by age, we found dementia in eight subjects (3.2%). Using a logistic regression model to estimate the risk of dementia associated with stroke in the combined samples, the odds ratio (OR) for stroke patients compared with control subjects was 9.4 (p less than 0.001). Advancing age and fewer years of education were significant, independent correlates of dementia, with a trend evident for race (non-white versus white). Confining the analysis to subjects residing in the Washington Heights-Inwood community of northern Manhattan, the OR was 10.3 (p less than 0.001) with significant age and race effects. We conclude that ischemic stroke significantly increases the risk of dementia, with independent contributions by age, education, and race.

Aged↗
PubMed1992

Requirement for specific protein kinase activities during the rapid redistribution of F-actin that precedes the outgrowth of neurites in PC12D cells.

Rapid changes in morphology of PC12D cells, a subline of PC12 cells, in response to various agents were studied in relation to the subsequent outgrowth of neurites. A few minutes after addition of NGF or of dbcAMP, staining of F-actin with rhodamine phalloidin revealed the formation of ruffles around the periphery of cells. Simultaneous relocalization of F-actin to the area of ruffles occurred in response to NGF. A moderate relocalization of F-actin occurred in dbcAMP-treated cells. Other neurite-promoting agents on PC12D cells, such as bFGF, EGF and PMA, also caused ruffling and an identical redistribution of F-actin. The actin bundles then condensed into several dot-like aggregates that subsequently became the growth cones of neurites. When an inhibitor of protein kinase, K-252a, was added, only the NGF-induced morphological change was selectively decreased. By contrast, an inhibitor of protein kinase A, H-89, selectively blocked the dbcAMP-induced change. These are analogous to the effects of those inhibitors on the outgrowth of neurites. These observations indicate that the formation of ruffles with the redistribution of F-actin might be one of the earliest steps in the neurite outgrowth and that the morphological changes might be triggered by the activation of specific protein kinases. Neither cytochalasin B nor colchicine prevented the series of morphological changes. However, processes formed in the presence of cytochalasin B had no filopodium and protrusions formed in the presence of colchicine were shaped like large filopodia. It appears that microtubules and microfilaments may not be absolutely required for the initiation of the rapid morphological changes, but that complete neurites might be formed with contribution by microtubules and by microfilaments.

Actins↗
PubMed1992

Synthesis and pharmacology of 3,4-dihydro-3-oxo-1,4-benzoxazine-8-carboxamide derivatives, a new class of potent serotonin-3 (5-HT3) receptor antagonists.

A series of 3,4-dihydro-3-oxo-1,4-benzoxazine-8-carboxamide derivatives was synthesized and evaluated for serotonin-3 (5-HT3) receptor antagonistic activity assessed by their ability to antagonize the von Bezold-Jarish (BJ) effect in rats. Derivatives bearing 1-azabicyclo[2.2.2]oct-3-yl moiety as a basic function attached to the carboxamide at position 8 showed more potent antagonistic activity than those bearing the other three basic moieties. Structure-activity relationships of this series showed that methyl and chloro groups were more effective as substituents at positions 4 and 6, respectively. The representative compound 15 (Y-25130) in this series showed potent antagonistic activity on the BJ effect (ED50 = 1.3 micrograms/kg i.v.), high affinity for 5-HT3 receptor (Ki = 2.9 nM) and complete protection against cisplatin-induced emesis in dogs at a dose of 0.1 mg/kg i.v.

Animals↗
PubMed1992

Beneficial effect of intravenous taurine infusion on electroretinographic disorder in taurine deficient rats.

We investigated the effect of intravenous taurine infusion on the electroretinogram (ERG) of taurine-deficient rats produced by treatment with guanidinoethyl sulfonate (GES), a taurine transport inhibitor. Mother rats were fed a taurine-free diet and given drinking water containing 1% GES from 2 weeks of gestation to weaning. The same feeding conditions were applied to male offspring after weaning. Both ERG measurement and continuous infusion of taurine at a dose of 10, 30 or 100 mg/animal/day were performed for 3 weeks from 7 to 10 weeks of age. GES-treatment reduced a- and b-wave amplitudes to 50% of the control levels and also increased b-wave latencies. Intravenous infusion of taurine improved these ERG abnormalities in a dose-dependent manner. Taurine concentrations in plasma, eyes and brain were also decreased by treatment with GES, and dose-dependent recovery was observed after infusion with taurine, although the concentrations of other amino acids were not affected by GES-treatment and infusion of taurine. Observations of morphological changes revealed that the retinal damage in GES-treated animals was decreased by taurine infusion. These results indicate that the changes in ERG and retinal structure observed in taurine deficiency are improved by intravenous infusion of taurine.

Amino Acids↗
PubMed1992

Vagal afferent activities and respiratory reflexes during drug-induced bronchoconstriction in the guinea pig.

Vagal afferent activities and respiratory reflexes during drug-induced bronchoconstriction were studied in 31 anesthetized, spontaneously breathing or artificially ventilated guinea pigs. Histamine (5, 10, 20 micrograms/kg), ACh (10, 20, 40 micrograms/kg) and endothelin-1 (2 micrograms/kg) were intravenously injected to the animals in order to induce the bronchoconstriction. In spontaneously breathing and vagi intact animals, a considerable respiratory change characterized by rapid-shallow breathing was elicited by histamine. Such respiratory change was abolished by bilateral vagotomy, indicating that the vagal pathway fairly participated in the respiratory change during bronchoconstriction. Indeed, recordings of electrical activities of single vagal afferent nerve fibers from pulmonary stretch and irritant receptors elucidated that the bronchoconstriction by the three drugs markedly influenced these receptor activities. The response of stretch receptors to bronchoconstriction was grouped into four types: two of those types showed a marked increase in their activities and the other two a decrease or no change. Such uneven response was assumed to be derived from heterogenous contraction and aeration among the intrapulmonary small airway. On the other hand, irritant receptors were invariably stimulated by increased transmural pressure during bronchoconstriction. Administration of isoproterenol (20 micrograms/kg) which inhibited the smooth muscle contraction abolished stimulatory effect of the drugs to irritant receptors, suggesting that the effect was due to indirect action through the muscle contraction rather than their direct action to the nerve endings.

Acetylcholine↗
PubMed1992

Disseminated intravascular coagulation in lupus erythematosus with acute liver damage.

A case of disseminated intravascular coagulation (DIC) in a patient with systemic lupus erythematosus (SLE) with acute liver dysfunction is described. A 37-year-old man with SLE developed acute DIC and marked liver damage after fracture of the right clavicle and pharyngitis. Treatment with high-dose steroids, heparin, antithrombin III, gabexate mesilate, and antibiotics resulted in prompt improvement. The recovery of an SLE patient after acute DIC and marked liver damage is considered very rare. We report here such a case and discuss the previous reports.

Adult↗
PubMed1992

Ovarian and hepatic metastases of gastric carcinoma associated with high serum levels of human chorionic gonadotropin (hCG), alpha-fetoprotein (AFP), and carcinoembryonic antigen (CEA): a case report.

A 45-year-old woman who underwent gastrectomy for gastric carcinoma which had metastasized to the liver and ovaries, showed high serum levels of hCG, AFP and CEA. To locate the source, an immunohistochemical technique was utilized. HCG-producing cells were detected in poorly differentiated adenocarcinoma of a primary tumor and an ovarian metastatic site, and AFP-producing cells in poorly differentiated adenocarcinoma forming a medullary pattern of primary site and metastatic foci. CEA-producing cells were found diffused in primary tumor and metastatic foci. From the viewpoint of oncodevelopmental gene expression (Cancer Res 36:3423, 1976), it is interesting that the serum levels of these three tumor markers (hCG, AFP, CEA) were elevated simultaneously.

Biomarkers, Tumor↗
PubMed1992

Pulmonary intralobar sequestration accompanied by aneurysm of an anomalous arterial supply.

A 47-year-old woman presented with hemoptysis and her chest X-ray films showed an opacity suggesting a mass in the left lower lung field. Based on radiographic investigations, the mass was diagnosed as an aneurysm develop in an anomalous vessel and was considered to be a Pryce type I pulmonary intralobar sequestration. Resection of the left lower lobes was performed and the aneurysm was found to be filled with thrombus. It is rare for an aneurysm to form in an aberrant vessel. This complication may have been the result of regional sclerosis affecting the anomalous artery as well as systemic atherosclerosis.

Aneurysm↗
PubMed1992

[A case of advanced breast cancer responding to low-dose 5'-DFUR].

A 69-year-old female patient with locally advanced breast cancer with multiple bone metastases (T4cN2-M1) was treated with 5'-DFUR after failure of tamoxifen treatment. The 5'-DFUR dose was limited to 600 mg per day, half the usual dose, because of its gastroenterological side effects. The primary tumor and metastatic axillary lymph nodes regressed three months after the start of treatment, and the complete remission of lesions was obtained in 16 months. Reduction of bone metastasis was confirmed by the disappearance of osteolytic lesion in the skull roentgenogram and the decrease of abnormal accumulation on the bone scintigram. Serum levels of CEA and ST-439 markedly reduced during the treatment as the disease regressed.

Aged↗
PubMed1992

Mechanism of immune complex-mediated inner ear diseases.

Tissues of the stria vascularis of normal rabbits were collected as cochlear antigen and injected into the foot pad of guinea pigs. The mechanism of development of endolymphatic hydrops was studied by the tracer method. Damage to the capillary endothelium and an increase in vascular permeability were found in the stria vascularis. Therefore, we studied patients with a raised level of immunoglobulin (Ig) G-class circulating immune complexes (CICs). Hearing loss was found in 3 of 22 patients with significantly elevated IgG CIC levels (13.6%). The relationship between inner ear disease and the presence of CIC was considered to be very significant. The possible mechanism of CIC-mediated inner ear diseases is discussed.

Adult↗