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Biomedical subjects

K Maeno

Publications and source records attributed to K Maeno.

At least 19 recordsLinked to original sources
PubMed2006

Altered regulation of c-jun and its involvement in anchorage-independent growth of human lung cancers.

The c-jun oncogene is frequently overexpressed in non-small-cell lung cancers (NSCLC), but its functional involvement in lung cancer development has not been clearly elucidated. In this study, we found that among the immediate-early serum responsible genes, exemplified by c-jun, c-fos and c-myc, induction of c-jun in a human bronchial epithelial cell line, BEAS-2B, was dependent on anchorage, in contrast to clear induction of c-fos and c-myc under both anchorage-dependent and -independent conditions. In fact, forced expression of c-jun in BEAS-2B cells significantly increased cell viability and colony formation in soft agar. Furthermore, we also found that such anchorage-dependent regulation of c-jun was lost in a significant fraction of human lung cancer cell lines. Interestingly, suppressed anchorage-independent but not anchorage-dependent growth was noted by constitutive expression of a dominant-negative c-jun mutant in a lung cancer cell line showing dysregulated and sustained c-jun expression in the absence of anchorage. These findings suggest that dysregulated c-jun expression may be involved in the acquisition of anchorage independence in the process of human lung carcinogenesis.

Bronchi↗
PubMed2004

Phase-related morphological changes induced by [His7]-corazonin in two species of locusts, Schistocerca gregaria and Locusta migratoria (Orthoptera: Acrididae).

The effects of a neurohormone, [His(7)]-corazonin, on phase-related morphological traits (F/C and E/F ratios; F = length of the hind femur, C = maximum width of the head; E = length of fore wing) were re-examined in the desert locust, Schistocerca gregaria Forskål. The F/C ratio was significantly different between adults with five and six nymphal instars, respectively, indicating that they need to be analysed separately. Injections of the synthesized peptide (1 nmol) into individually-reared (solitary) nymphs at the second and third instars caused a shift in classical morphometric ratio towards the value typical for crowded (gregarious) individuals in both sexes. The E/F ratio, which is smaller in solitary locusts than in gregarious ones, was also influenced significantly by injections of [His(7)]-corazonin into individually-reared locusts. The effect of [His(7)]-corazonin on E/F ratios was shown more clearly when the nymphs were injected at a higher dose (2 nmol) at the beginning of the third instar. Single injections of the peptide into individually-reared nymphs at different instars revealed that the earlier the injection the larger the 'gregarizing' effects of the peptide on F/C and E/F ratios. The same tendency was also detected in Locusta migratoria Linnaeus. These results supported the hypothesis that [His(7)]-corazonin plays an important role in the control of phase polymorphism in locusts.

Animals↗
PubMed2002

Classification of abomasal displacement in cows according to histopathology of the liver and clinical chemistry.

Histopathological features of livers and blood chemical values in cows with abomasal displacement were investigated. Liver biopsy samples were collected during redressment operations in 92 cows with abomasal displacement, and the samples were stained with haematoxylin and eosin or periodic acid Schiff (PAS). Blood was collected for chemical tests. Livers were histopathologically divided into the following four types: normal histology cases (21%), fatty degeneration cases (36%), cloudy swelling cases (19%) and fatty degeneration cases with cloudy swelling (24%). The number of PAS-positive samples was significantly higher in the normal histology group and significantly lower in the severe fatty degeneration group and severe cloudy swelling group. Cows with fatty degeneration had significantly higher levels of serum 3-hydroxybutyric acid, non-esterified fatty acid and aspartate aminotransferase than did those with cloudy swelling or normal histology. The results indicate that the morbid conditions of cows with abomasal displacement can be classified into four types.

3-Hydroxybutyric Acid↗
PubMed2001

Association between the dopamine D2 receptor A2/A2 genotype and smoking behavior in the Japanese.

For the study presented here, we investigated possible links between the dopamine D2 receptor (DRD2) TaqIA genotype (DRD2*A) and smoking behavior in a total of 332 Japanese individuals. For the first time, functional insertion/deletion polymorphism (-141C Ins/Del) in the DRD2 promoter was also examined in relation to smoking behavior. The distribution of the DRD2*A genotype was significantly different among current, former, and never-smokers (P = 0.001; chi(2) test), and smoking appeared to be associated with the DRD2 A2/A2 genotype, showing marked contrast to previous reports for non-Hispanic whites in the United STATES: Multivariate logistic regression analysis incorporating age, sex, genotype, and smoking status as variables revealed that DRD2 A2/A2 genotype was significantly associated with an increased risk of predisposition to smoking behavior in the Japanese (odds ratio, 3.680; 95% confidence interval, 1.499-9.052). In contrast, such an increased risk was not observed in terms of association with the -141C Ins/Del polymorphism. These findings suggest an association of the DRD2*A genotype with an increased risk of being predisposed to smoking behavior in the Japanese and suggest the possible existence of ethnic group-specific differences, which warrant additional studies on the underlying molecular mechanism.

Adult↗
PubMed2000

Trisomy 14 with thrombocytosis and monocytosis.

It has been reported that trisomy 14 is associated with myeloid malignancies, but a case with increased platelet count has also been reported. However, the clinical significance of trisomy 14 is still uncertain. We report a patient with trisomy 14 with thrombocytosis and a gradual increase in monocytosis. He was treated with hydroxyurea, cytarabine and aclarubicin in low doses and his quality of life was maintained for a period of about 1 year from blastic crisis. Hydroxyurea, cytarabine or aclarubicin in low doses may be the treatment of choice for trisomy 14 patients with respect to the patients' quality of life.

Aclarubicin↗
PubMed1999

[Nontuberculous mycobacterial disease in a general hospital].

Annual incidence of nontuberculous mycobacterial (NTM) disease has been gradually increasing in the last 10 years in Japan. It is likely to encounter this disease not only in hospitals specialized in mycobacterial diseases but also in general hospitals. NTM were isolated from 97 cases between January 1990 and June 1996 at our hospital. Out of them, 41 patients were diagnosed as NTM disease. Mycobacterium avium complex (MAC) was the most frequent pathogens (68.3%) and M. kansasii (22%) was the next. Other pathogens were M. chelonae (4.9%), M. fortuitum (2.4%) and M. szulgai (2.4%). Results obtained in our hospital were very similar to the rates which have been reported previously. Patients with MAC infection showed relatively poor prognosis (eight patients were died out of 28 patients with MAC) in this study compared with the cases reported in previous papers, and this result could be explained by the severity of illness when they were admitted to our hospital, the insufficiency of the initial treatment which should be started with the combined use of three to four antibacterial drugs including clarithromycin, and to a low dosage of clarithromycin compared with conventionally adopted dosage. Unlike tuberculosis, human to human transmission is considered to be negligible in the case of NTM disease, and general hospitals are able to provide medical care to the patients with NTM disease. Rather, if general hospitals which are located in the region near to the patients residence can play more active role in the treatment of NTM disease, it would be more beneficial to patients requiring long-term follow-up observation. Based on the result that similar therapeutic results were obtained for infections with other NTM as reported in previous papers, it is indicated that general hospitals are able to provide medical care to patients with NTM disease if therapeutic regimens recommended by specialist are sufficiently understood and applied.

Female↗
PubMed1998

[A case of dural arteriovenous fistula in the transverse and sigmoid sinus which developed over five years].

We report a case of dural arteriovenous fistula (dAVF) of the transverse and sigmoid sinus which developed over five years. The patient was a 64-year-old man, who had a history of congestive heart failure and transient ischemic attack (TIA). No abnormal lesions were detected in the cerebral angiograms five years prior to the time the etiology of his TIA was investigated. He suddenly suffered from left hemiparesis and the CT scan showed right parietal subcortical hemorrhage. Right carotid angiogram demonstrated dAVF of the transverse and sigmoid sinus supplied by the right occipital and ascending pharyngeal arteries. We thought the reason for the subcortical hemorrhage in this patient was due to the disturbance of venous return in the right cerebral hemisphere. We underwent direct embolization of the right transverse sinus by interlocking detachable coils. Postoperative cerebral angiograms demonstrated the disappearance of dAVF and he was discharged. Whether dAVF is a congenital anomaly or not, has been controversial. Since the dAVF in this case had newly developed over five years, it is suggested that dAVF is an acquired lesion.

Arteriovenous Fistula↗
PubMed1997

Mixed connective tissue disease associated with acute polyradiculoneuropathy.

A rare case of mixed connective tissue disease (MCTD) with acute polyradiculoneuropathy is reported. A 23-year-old woman presented with high body temperature, arthralgia and a headache, and developed gait disturbance two weeks later. She had many clinical features common to patients with MCTD. Her neurological manifestations were diagnosed as acute polyradiculoneuropathy based on the clinical picture, combined with supportive ancillary data, including cerebrospinal fluid (CSF) analysis, electrophysiological evaluation, sural nerve biopsy, peroneus brevis muscle biopsy, and magnetic resonance imaging (MRI). Her neurologic deficits, as well as associated laboratory findings, were improved by corticosteroid therapy.

Acute Disease↗
PubMed1996

YM-50001: a novel, potent and selective dopamine D4 receptor antagonist.

We investigated some in vitro pharmacological properties of a novel human dopamine D2-like receptor antagonist, YM-50001 [(R)-5-chloro-4-cyclopropylacarbonylamino-2-methoxy-N-[1-(3-methox ybenzyl)- 3-pyrrolidinyl]benzamide monooxalate]. Receptor binding studies revealed that YM-50001 had a potent affinity for human D4 receptors (Ki = 5.62 nM). YM-50001 displayed weak or negligible affinity for other neurotransmitter receptors including human D2 and D3 receptors. YM-50001 shifted the dopamine response curve on each human D2-like receptor subtype-mediated low-Km GTPase activity to the right. YM-50001 also exhibited good D4 selectivity with respect to D2-like receptor antagonism in the functional assay. These results indicate that YM-50001 is a novel, potent and selective D4 receptor antagonist.

Benzamides↗
PubMed1996

Dopamine D3 and D4 receptor antagonists: synthesis and structure--activity relationships of (S)-(+)-N-(1-Benzyl-3-pyrrolidinyl)-5-chloro-4- [(cyclopropylcarbonyl) amino]-2-methoxybenzamide (YM-43611) and related compounds.

In this study, we synthesized a series of (S)-N-(3-pyrrolidinyl)benzamide derivatives, 1, 2a-d, 5a-1, and 7, and their enantiomers, (R)-1 and (R)-5c-e, and evaluated their binding affinity for cloned dopamine D2, D3, and D4 receptors and their inhibitory activity against apomorphine-induced climbing behavior in mice. The results indicate that D2, D3, and D4 receptors have different bulk tolerance (D4 > D3 > D2) for the substituent of the 4-amino group (R1) on the benzamide nuclei and that cyclopropyl-, cyclobutyl-, and cyclopentylcarbonyl groups likely possess adequate bulkiness with respect to D3 and D4 affinity and selectivity over D2 receptors in this series. The results also suggested that the N-substituent (R2) on the pyrrolidin-3-yl group performs an important role in expressing affinity for D2, D3, and D4 receptors and selectivity among the respective subtypes. One of the compounds, (S)-(+)-N-(1-benzyl-3-pyrrolidinyl)-5-chloro-4-[(cyclopropylcarbonyl+ ++) amino]-2-methoxybenzamide (5c) (YM-43611), showed high affinity for D3 and D4 receptors (Ki values of 21 and 2.1 nM, respectively) with 110-fold D4 selectivity and 10-fold D3 preference over D2 receptors and weak or negligible affinity for representative neurotransmitter receptors. Compound 5c displayed potent antipsychotic activity in inhibiting apomorphine-induced climbing behavior in mice (ED50 value, 0.32 mg/kg sc).

Animals↗
PubMed1996

[Bilateral carotid endarterectomy for patients with bilateral carotid artery stenosis].

In a couple of recent randomized trials, the benefits of unilateral carotid endarterectomy (CEA) have been reevaluated in symptomatic patients with severe stenosis. In contrast, the operative indication, procedure, and perioperative management of bilateral CEAs for patients with bilateral carotid artery stenosis are still controversial. In this report, we reviewed 7 patients who underwent bilateral CEAs at out institute during the last 10 years, with regard to the clinical feature, angiographical findings, operative procedure, surgical results and long-term prognosis. The patients ranged from 52 to 73 years in age, and included six males and one female. Clinical symptoms were asymptomatic in 1 patient, transient ischemic attack in 2, reversible ischemic neurological deficits in 2, minor completed stroke in 1, and major completed stroke in 1. The angiographical carotid artery stenosis in the dominant side of symptomatic cases was 50% in 3, 70% in 1, 90% in 2, and ulceration in 4 cases. The stenosis in the non-dominant side of symptomatic cases was 60% in 1, 70% in 3, 90% in 2, and 4 cases with ulceration. One case among the asymptomatic cases had bilateral 80-90% stenosis. We staged bilateral CEAs, in the dominant side first except in one case among the symptomatic cases and on the more severely stenotic side first in the asymptomatic cases. During CEA, an external shunt was placed in 1 case, but no internal shunt was used in any of the cases. Perioperative complications were found in 2 patients, transient bilateral hypoglossal nerve palsy and local hemorrhage in the other case. Totally, all of 7 cases (14 consecutive CEAs) have been performed with satisfactory results. No mortality and no permanent morbidity has resulted. In the follow-up period (mean: 38.3 month), 1 patient was found to have developed cerebral infarction in the ipsilateral carotid artery territory. From our own small experience and from that in the literature, CEAs for bilateral carotid artery stenosis should be performed in the dominant side first. Then, after a certain period, from 2 to 6 weeks, the CEA should be performed in the non-dominant side.

Aged↗
PubMed1994

Isolation and classification of temperature-sensitive mutants of influenza B virus.

We isolated 25 temperature-sensitive mutants of B/Kanagawa/73 strain generated by mutagenesis with 5-fluorouracil and classified them into seven recombination groups by pair-wise crosses. All mutants showed a ratio of plaquing efficiency at the nonpermissive temperature (37.5 C) to the permissive temperature (32 C) of 10(-4) or less. At 37.5 C most of group I, II, and III mutants did not produce appreciable amounts of protein, but all other group mutants were protein synthesis-positive. A group VII mutant produced active hemagglutinin (HA) and neuraminidase (NA) at the nonpermissive temperature, but Group V mutants produced only active NA and were defective in the HA molecule. The other group mutants, including group IV mutants with mutation only in the NA gene (8, 10), lacked both activities at the nonpermissive temperature. One of nine influenza B virus isolates in 1989 had EOP 37.5/32 of 1/3 x 10(-2) and belonged to recombination group VII.

Animals↗
PubMed1994

Approach to the involvement of influenza B neuraminidase in the cleavage of HA by host cell protease using low pH-induced cell fusion reaction.

ts7, a temperature-sensitive mutant defective in neuraminidase (NA) of influenza B/Kanagawa/73, lacks NA enzymatic activity at the nonpermissive temperature (37.5 C). When MDCK cells were infected with the mutant at the permissive temperature (32 C) and exposed to pH 5.2 medium, extensive cell fusion occurred. In contrast, at the nonpermissive temperature cells did not show cell fusion at all unless they were pretreated with trypsin, suggesting that at 37.5 C the hemagglutinin (HA) of ts7 is expressed at the cell surface in an uncleaved form. It was also found that the replacement of RNA segment 6 of ts7 with that of wild-type B/Lee resulted in the emergence of low pH-induced fusion activity as well as NA enzymatic activity at the incubation temperature of 37.5 C and that the addition of bacterial NA to the cultures infected with ts7 at 37.5 C early in infection brought about low pH-induced cell fusion. We suggest that the removal of neuraminic acid from the carbohydrate moiety of HA by NA is essential for the cleavage of HA by cellular protease.

Animals↗
PubMed1994

Role of neuraminidase in the morphogenesis of influenza B virus.

When ts7, a temperature-sensitive (ts) mutant of influenza B/Kanagawa/73 virus, infected MDCK cells at the nonpermissive temperature (37.5 degrees C), infectious virus was produced at very low levels compared with the yield at the permissive temperature (32 degrees C) and hemagglutinating activity and enzymatic activity of neuraminidase (NA) were negligible. However, viral protein synthesis and transport of hemadsorption-active hemagglutinin to the cell surface were not affected. When the cell lysate was treated with bacterial NA, hemagglutinating activity was recovered but infectivity was not, even after further treatment with trypsin. It was found that ts7 was defective in transport of NA to the cell surface and formation of virus particles. Analysis of the genomes of non-ts recombinants obtained by crossing ts7 and UV-inactivated B/Lee showed that ts7 had the ts mutation only in RNA segment 6 coding for NA and the glycoprotein NB. Nucleotide sequence analysis of the RNA segment revealed that ts7 had four amino acid changes in the NA molecule but not in NB. We suggest that assembly or budding of influenza B virus requires the presence of NA at the plasma membrane, unlike influenza A virus.

Amino Acid Sequence↗
PubMed1993

Purification and biochemical characterization of the protein kinase encoded by the US3 gene of herpes simplex virus type 2.

Post-ribosomal cytoplasmic fractions from Vero cells mock-infected or infected with wild-type herpes simplex virus type 2 (HSV-2) or a US3 gene-disrupted mutant of HSV-2 were fractionated with DEAE-cellulose chromatography, and the peak fraction of the protein kinase which was detectable only in the extract of wild-type virus-infected cells was subjected to successive chromatography. The enzyme was purified more than 1000-fold from the post-ribosomal supernatant, and the final preparation contained one major protein of apparent molecular weight 66 kilodalton (K), which was phosphorylated in the autophosphorylation reaction. Western blotting analysis showed that antibodies to an synthetic peptide corresponding to the 15 amino acids of the predicted HSV-2 US3 protein sequence strongly reacted with a 66 K protein in the enzyme fractions. On Superose 12 HR chromatography, the protein kinase activity was eluted as a single major peak at a position corresponding to an apparent molecular mass of approximately 60 K. These results suggest that the 66 K protein is the protein kinase encoded by the US3 gene of HSV-2 and that it acts as a monomer. The HSV-2 protein kinase was relatively resistant to high concentrations of salt, but KCl above 400 mM exerted a significant inhibitory effect. When the substrate specificity was investigated using synthetic oligopeptides, the peptides containing arginyl residues on the amino-terminal side of the target seryl residue were found to be the best substrates for the protein kinase. However, the replacement of the seryl residue to threonine markedly reduced the rate of phosphorylation by this enzyme, suggesting that threonine is a poor phosphate acceptor of the protein kinase. The enzyme was resistant to heparin, a potent inhibitor of casein kinase II, but was moderately sensitive to H-9 (N-(2-aminoethyl)-5-isoquinolinesulfonamide dihydrochloride), a potent inhibitor of cyclic nucleotide-dependent protein kinases and protein kinase C. Quercetin, a bioflavonoid, also inhibited the protein kinase and the inhibitory effect was competitive towards ATP (Ki = 10 microM). The results indicate that the biochemical properties of the HSV-2 US3 protein kinase are very similar to those of the HSV-1 counterpart and pseudorabies virus-encoded 38-kDa protein kinase, but are different from those in several respects.

Adenosine Triphosphate↗
PubMed1993

The pathogenicity of a US3 protein kinase-deficient mutant of herpes simplex virus type 2 in mice.

We have investigated the pathogenicity of a US3 protein kinase-deficient mutant (L1 BR1) of herpes simplex virus type 2 (HSV-2) for 4-week-old ICR mice to define the role of the viral protein kinase in virus-host interaction. When mice were intraperitoneally infected with 10(5)PFU of L1 BR1, the virus disappeared from the peritoneal cavity by 2 days postinfection and failed to induce any significant histopathological changes in the liver and spleen although viral antigens were occasionally detected in the epithelial cells of small bile ducts and small vascular wall. The parental virus (HSV-2 186) and a revertant of the mutant (L1 B-11) both caused severe hepatitis, and viral antigens were clearly detected in the hepatocytes and Kupffer cells in the focal necrotic areas. Both of the virulent viruses, unlike L1 BR1, could produce infectious progeny and cytopathic effects in freshly harvested peritoneal macrophages. The growth of L1 BR1 in peritoneal macrophages was restricted at a stage of or prior to viral DNA synthesis but after the induction of viral DNA polymerase. In addition, the production and/or the spread of mutant in mouse embryo fibroblasts (MEF) was found to be much more effectively suppressed by cocultivation of peritoneal macrophages than that of 186. An almost complete inhibition of L1 BR1-plaque formation was observed at a macrophage-to-MEF ratio of 4:1. These results suggest that the attenuation of L1 BR1 following intraperitoneal infection is primarily due to its high sensitivity to intrinsic and extrinsic inhibition of peritoneal macrophages and that the US3 protein kinase may play a role in viral DNA replication in peritoneal macrophages.

Animals↗
PubMed1993

Characterization of a temperature-sensitive influenza B virus mutant defective in neuraminidase.

ts5, a temperature-sensitive mutant of influenza B virus, belongs to one of seven recombination groups. When the mutant infected MDCK cells at the nonpermissive temperature (37.5 degrees C), infectious virus was produced at very low levels compared with the yield at the permissive temperature (32 degrees C) and hemagglutinating and enzymatic activities were undetectable. However, viral protein synthesis and transport of hemagglutinin (HA) and neuraminidase (NA) to the cell surface were not affected. The NA was found as a monomer within cells even at 32 degrees C, in contrast to wild-type virus NA, existing mostly as an oligomer, but the mutant had oligomeric NA, like the wild-type virus. Its enzymatic activity was more thermolabile than that of wild-type virus. Despite the low yield, large aggregates of progeny virus particles were found to accumulate on the cell surface at the nonpermissive temperature, and these aggregates were broken by treatment with bacterial neuraminidase, with the concomitant appearance of hemagglutinating activity, suggesting that NA prevents the aggregation of progeny virus by removal of neuraminic acid from HA and cell receptor, allowing its release from the cells. Further treatment with trypsin resulted in the recovery of infectivity. When bacterial NA was added to the culture early in infection, many hemagglutinable infectious virus was produced. We also suggest that the removal of neuraminic acid from HA by NA is essential for the subsequent cleavage of HA by cellular protease. Nucleotide sequence analysis of RNA segment 6 revealed that ts5 encoded five amino acid changes in the NA molecule but not in NB.

Amino Acid Sequence↗