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Biomedical subjects

N Okazaki

Publications and source records attributed to N Okazaki.

At least 37 records · Page 2Linked to original sources

HRA model for hypercholesterolemia based on a longitudinal health database.

To evaluate the risk factors for hypercholesterolemia, we examined 4,371 subjects (3,207 males and 1,164 females) who received medical checkups more than twice at an AMHTS in Tokyo during the period from 1976 through 1991; and whose serum total cholesterol was under 250 mg/dl. The mean follow-up duration was 6.6 years. A self-registering questionnaire was administered at the time of the health checkup. The endpoint of this study was the onset of hypercholesterolemia when the level of serum total cholesterol was 250 mg/dl and over. We compared two prognosis groups (normal and hypercholesterol) in terms of age, examination findings and lifestyle. After assessing each variable, we employed Cox's proportional hazards model analysis to determine the factors related to the occurrence of hypercholesterolemia. According to proportional hazards model analysis, total cholesterol, triglyceride and smoking at the beginning, and hypertension during the observation period were selected in males; and total cholesterol at the beginning and age were selected in females to determine the factors related to the occurrence of hypercholesterolemia.

Adult↗

Sequence of a melibiose transporter gene of Enterobacter cloacae.

We cloned a fragment of the chromosomal DNA of Enterobacter cloacae, which enabled a melibiose-negative Escherichia coli mutant lacking melB to grow on melibiose as the sole source of carbon. Transformed cells harboring the hybrid plasmid carrying the cloned DNA showed melibiose transport activity. The nucleotide sequence of the DNA region was determined. One complete open reading frame (ORF) and a part of another ORF were found in the region, and the amino acid sequences were deduced. The complete ORF was found to encode a melibiose transporter which consisted of 425 amino acid residues. Hydropathy analysis revealed that there are about 12 hydrophobic domains in this transporter. The incomplete ORF which exists in the upstream region of the transporter gene seemed to encode an alpha-galactosidase.

Amino Acid Sequence↗

Characteristics of the melibiose transporter and its primary structure in Enterobacter aerogenes.

Cells of Enterobacter aerogenes can grow on melibiose as a sole source of carbon. This suggests the presence of melibiose operon in this organism. We found that E. aerogenes cells possess both alpha-galactosidase activity and melibiose transport activity, which were induced by melibiose. Neither Na+ nor Li+ stimulated the melibiose transport. However, transport of methyl-beta-thiogalactoside (TMG) was stimulated by Li+ but not by Na+. These findings suggest that the major coupling cation for the melibiose transporter in E. aerogenes is H+. In fact, we observed H+ entry into cells caused by an influx of melibiose and some of its analogs. We cloned the melB gene which encodes the melibiose transporter, and sequenced it. Deduced amino acid sequence of the transporter revealed that the melibiose transporter consists of 471 amino acid residues and the molecular weight was calculated to be 52214 Da. The sequence showed high homology with the sequences of the melibiose transporters of Escherichia coli, Salmonella typhimurium and Klebsiella pneumoniae. Higher homology was found with the melibiose transporter of K. pneumoniae than with that of E. coli and S. typhimurium.

Amino Acid Sequence↗

Isoflurane inhibits endothelium-mediated nitric oxide relaxing pathways in the isolated perfused rabbit lung.

PURPOSE: The role of volatile anaesthetics on nitric oxide (NO)-dependent relaxation is unclear in the pulmonary circulation. We examined the effects of isoflurane on NO-dependent relaxation in isolated perfused rabbit lungs. METHODS: Eighteen rabbit lungs were perfused in a constant-flow recirculation manner. In study 1 (n = 12), acetylcholine (ACh, 4 x 10(-10)-10(-8) M) or nitroglycerine (NTG, 6 x 10(-10)-10(-8) M) was cumulatively injected into the pulmonary artery in the absence or presence of isoflurane (1, 2 MAC). In study 2 (n = 6), ACh was injected as in study 1 in the presence or absence of N omega-nitro-L-arginine methyl ester (L-NAME, 100 microM), an NO synthesis blocker. In all experiments, indomethacin was administered to prevent formation of vasoactive prostanoid metabolites, and the pulmonary vessels were preconstricted with prostaglandin F2 alpha (PGF2 alpha) infused before ACh or NTG injection. The ACh- or NTG-induced relaxation was expressed as % decrease in PGF2 alpha preconstriction. RESULTS: Isoflurane at 2 MAC attenuated the dose-dependent relaxation to ACh at doses of 4 x 10(-9) M and 4 x 10(-8) M from 27.8 +/- 4.3% and 38.8 +/- 5.3% to 17.0 +/- 3.5% and 25.5 +/- 4.9%, respectively (P < 0.05). Isoflurane did not change the dose-dependent relaxation to NTG and L-NAME abolished the ACh-induced relaxation. CONCLUSION: Isoflurane inhibited NO-dependent relaxation in the pulmonary circulation at a site distal to the endothelial cell receptor-mediated responses but proximal to guanylate cyclase activation of vascular smooth muscle. Acetylcholine-induced relaxation in isolated perfused rabbit lungs was regulated primarily by NO.

Acetylcholine↗

A melibiose transporter and an operon containing its gene in Enterobacter cloacae.

We detected inducible melibiose transport activity in cells of Enterobacter cloacae IID977. H+, but not Na+, was found to be the coupling cation for this transporter. We cloned and sequenced the gene encoding the melibiose transporter. A homology search of a protein sequence database revealed that this melibiose transporter has high sequence similarity with the lactose transporter (LacY) and the raffinose transporter (RafB) and has some similarity with the melibiose transporter (MelB) of Escherichia coli.

Amino Acid Sequence↗

[Studies on enrichment broth for verotoxin-producing Escherichia coli (VTEC) O157].

Growth of verotoxin-producing Escherichia coli (VTEC) O157 in conventionally recommended pre-enrichment broth media at different temperatures was evaluated. In addition, sensitivity of VTEC O157 isolates to several antibacterial drugs, which were added to the selective enrichment broth, was tested. All five isolates of VTEC O157 tested grew well in trypticase soy broth (TSB) at 36 degrees C and 42 degrees C, while the growth of one isolate was markedly suppressed in TSB supplemented with cefixime (CFIX), potassium tellurite (PT), and vancomycin (TSB-CTV) even at 36 degrees C. A significant growth suppression was also observed in three of the isolates cultured in novobiocin (NB)-supplemented modified EC broth (mEC-NB) at 42 degrees C. In mEC-NB after 24-hr incubation at 36 degrees C, the five VTEC O157 isolates grew well, although one isolate was slightly suppressed during the first 8 hours. Minimum growth inhibitory concentrations of CFIX, NB and PT for a total of 90 clinical and environmental isolates of VTEC O157 were all above the concentrations usually prescribed for mEC-NB and TSB-CTV. These findings suggest that mEC-NB and TSB-CTV should be used at 36 degrees C for growth of VTEC O157 and that use of a nonselective pre-enrichment broth medium (i.e. TSB) together with a selective one (i.e. TSB-CTV or mEC-NB) is necessary for successful isolation of VTEC O157 from various specimens.

Aeromonas↗

Cloning and characterization of the Pichia pastoris PRC1 gene encoding carboxypeptidase Y.

We purified a 58 kDa serine protease from culture-supernatant of Pichia pastoris and found that the NH2-terminal amino acid sequence of this protease is closely homologous to that of mature protein of Saccharomyces cerevisiae carboxypeptidase Y (CPY), which is encoded by the PRC1 gene. Using the S. cerevisiae PRC1 gene as a hybridization probe, a cross-hybridizing fragment of P. pastoris genomic DNA was identified and the gene, PRC1, encoding CPY, was cloned. The open reading frame of the P. pastoris PRC1 gene consists of 1569 bp encoding a protein of 523 amino acids. The molecular mass of the protein is calculated to be 59.44 kDa without sugar chains. The protein comprises 20 amino acids of pre (signal)-peptide, 87 amino acids of pro-peptide and 416 amino acids of mature peptide, and has four N-glycosylation sites. The NH2-terminal amino acid sequence of mature peptide is completely identical with that of the protease purified from the culture-supernatant. There is 61% identity between the amino acid sequences of P. pastoris Prc1p and S. cerevisiae Prc1p. Chromosomal disruption of the PRC1 gene resulted in the loss of CPY activity. Over-expression of the PRC1 gene under regulation of the P. pastoris AOX1 promoter resulted in accumulation of a large amount of active CPY in the intracellular fraction, and secretion of a slightly larger molecule that is thought to be pro-CPY. The nucleotide sequence data reported in this paper will appear in the EMBL Nucleotide Sequence Databases under the Accession Number X87987.

Amino Acid Sequence↗

Epidemiological study of Mycoplasma pneumoniae infections in japan based on PCR-restriction fragment length polymorphism of the P1 cytadhesin gene.

Two hundred fifty strains of Mycoplasma pneumoniae isolated during the past 20 years in Japan were classified into two groups (I and II) based upon different PCR-restriction fragment length polymorphism patterns of their P1 cytadhesin genes. Clear shifts between the M. pneumoniae groups were observed but did not appear to be correlated with M. pneumoniae epidemic cycles. Patients' sera showed relatively higher levels of antiadhesin antibodies to M. pneumoniae strains homologous with the infecting strain.

Adhesins, Bacterial↗

[A research on the importance of the clinical certificate to the medical practitioners outside the field of psychiatry. Committee on graduate education sub-committee on Feasibility of Implementing Specialty Board Certification in the Japanese Society of Psychiatry and Neurology].

OBJECTIVES AND METHODS: The main objectives of the research was to identify the merits and demerits of the specialty board certification system, that had been implemented in the other medical societies than the society of psychiatry in Japan. As a measure of the research, we conducted a survey by distributing questionnaires to medical institutions. The subjects of this survey included medical practitioners, other than the psychiatrists, who belong to general hospital, university hospital and the Japan Medical Association. FINDINGS: We received 228 responses out of the subjects. The findings were that 86% of the subjects have acquired the specialty board certificate, and that half of them have more than two kinds of qualifications on the average. Thus, the report suggests that the specialty board certification system have been long pervaded throughout the medical fields outside psychiatry. In addition, the subjects pointed out as the merits of the specialty board certification system that it helps to achieve the higher level of technique, and to organize and sophisticate as well as widen the knowledge of their specialty. They also reported that it contributes to instigate the life-long education and to earn identification and recognition of their specialty from other fields of medicine than their own. Fifty-three percent of the subjects acknowledged the necessity of the specialty board certification system while 13% regarded it unnecessary. This result proves that, despite higher percentage of the doctors with qualifications, the system itself is not approved of with full acknowledgement in the medical world. This rather negative attitudes toward the system is originated in the fact that acquiring and maintaining the certificate, i.e., renewal fees, are considerably high. In fact, as many as 62% of the subjects felt these points as disadvantages of the system. The medical practitioners outside the fields of psychiatry did not show any particular concern about the lack of the specialty board certification system in our field that is distinct as a field of medicine. Only 18% of the subjects expressed that urgent actualization of the system is desirable in our fields. In addition, securing the cites required for learning the technique and giving the exam to the applicants is the most important matter to be concerned. On the contrary, in other fields of medicine, the matter does not need to be discussed. Therefore, this is a problem unique to the fields of psychiatry. CONCLUSION: Although there are disadvantage of the specialty board certification system pointed out as shown above, we believe that it is necessary to introduce the system in the field of psychiatry. These disadvantage are mainly the matter of individual income. We need to consider the introduction of the system from the perspective of sophisticating the quality of psychiatry as a field of medicine in our country. We, the Subcommittee on feasibility of implementing specialty board certification in the Japanese Society of Psychiatry and Neurology have been contemplating over the system up to this moment. The progress has been made to the point of presenting, Discussion of the Specialty Board Certification System in Psychiatry, Yamauchi, May, 1994.

Certification↗

[Detection of Mycoplasma pneumoniae from throat swab by polymerase chain reaction].

Polymerase chain reaction (PCR) with primers directed against the 16S-rRNA gene of Mycoplasma pneumoniae was used to diagnose M. pneumoniae infections, and the results were compared with those of culture and serology methods. Eighty (22%) of 363 throat swab samples from patients with acute respiratory complaints gave positive results by using the PCR method. Sixty-seven (18.5%) of the samples were positive in culture method. Of 35 samples which were unreliable culture results due to contamination with other bacteria, 13 gave positive results in the PCR method. Of the 97 cases obtained throat swabs and paired sera, 28 (28.9%) showed positive results by the PCR assay, and 29 (29.9%) by serology method (particle agglutination test). The positive rate was increased to 36% by using both the PCR and the serology methods. From these results it was concluded that the PCR method is useful for laboratory diagnosis of M. pneumoniae infections.

Base Sequence↗

[Alcohol beverage advertisements--survey of weekly magazines].

This paper presents an analysis of alcohol beverage advertisements appearing in weekly magazines and comics. Few studies have be undertaken on this sector of the mass media in Japan. The results are compared with those of a similar study in the United States. We also review alcohol advertisements on television and the drinking scenes shown in comics. On the average, Japanese magazines tend to contain fewer alcohol advertisements than American magazines. However, 18 (53%) in 34 weekly magazines contained alcohol advertisements showing that such magazines are an important medium for alcoholic beverage advertising in Japan. There were also alcohol advertisements targeting to particular populations, youths and women, which may be connected with the increase in drinking in these groups. Alcohol advertisements in the mass media should be monitored continuously as public health issue.

Advertising↗

[Inhibition of pulmonary vasoconstriction by inhaled nitric oxide].

We examined effects of inhaled NO gas on pulmonary vasoconstriction induced with hypoxic gas or PGF2 alpha utilizing the isolated perfused rabbit lung. While NO 180 ppm did not change the basal pulmonary artery pressure, the pressure response to hypoxia or PGF2 alpha was completely inhibited by pretreatment with NO inhalation. Inhaled NO during maximal pressor response also depressed the elevated pressure to the basal level. These findings suggest that NO inhaled to the alveoli diffuses directly into the pulmonary vascular smooth muscle and then causes nonspecific vasodilation, and its effect is more potent than that of constitutive type of EDRF/NO.

Administration, Inhalation↗

Cloning and sequencing of the gene for the lactose carrier of Citrobacter freundii.

The gene coding for the lactose carrier of Citrobacter freundii was cloned into the plasmid pBR322. The gene was sequenced and the amino acid sequence was found to be 70% identical to the lactose carrier of E. coli. All of the charged residues in the membrane spanning region were conserved. The sugar specificity is somewhat different from that of E. coli. The C. freundii carrier has less activity for lactose and more activity for o-nitrophenyl-galactose (ONPG) than the carrier of E. coli.

Amino Acid Sequence↗

Characterization of the lactose transport system in Citrobacter freundii.

The lactose transport system of Citrobacter freundii was characterized. Both the lactose transport system and beta-galactosidase were induced with either lactose or isopropyl-beta-D-thiogalactopyranoside (IPTG), the latter being the better inducer. The Km values for methyl-beta-D-thiogalactopyranoside (TMG) transport and lactose transport were 0.61 mM and 1.1 mM, respectively, and the Vmax values were 53 nmol/min/mg cell protein and 12 nmol/min/mg cell protein, respectively. Thus, TMG is a better substrate than lactose. Thiogalactopyranoside (TDG) was a very potent competitive inhibitor. Neither Na+ nor Li+ had a significant effect on the TMG transport or the lactose transport. Proton/substrate cotransport (symport) via this system was observed.

Citrobacter freundii↗

Hyperresponsiveness of cardiac muscles to histamine in reserpine-treated guinea pigs.

The hyperresponsiveness of cardiac tissue to histamine following treatment with reserpine was pharmacologically characterized. Guinea pig hearts were isolated 24 hours after intraperitoneal administration of 5 mg/kg reserpine. This treatment resulted in a complete depletion of tissue norepinephrine. Reserpine treatment potentiated the positive inotropic response of isolated perfused hearts to histamine at doses ranging from 0.3 to 3 micrograms (23 to 57% increase for reserpine-treated animals vs. 14 to 32% increase for control animals). Isolated left ventricular papillary muscle of reserpine-treated guinea pig hearts also showed hyperresponsiveness to histamine at concentrations of 0.1 microM or greater. The hyperresponsiveness of the papillary muscle contraction of the reserpine-treated animals to histamine was abolished in the presence of 1 microM cimetidine, but not attenuated in the presence of 1 microM diphenhydramine. This hyperresponsiveness was not modified by 1 microM bunazosin or 1 microM propranolol. The results suggest that H2-receptor mediated action plays a role in the hyperresponsiveness of cardiac muscles to histamine.

Animals↗

Radiotherapy for hepatocellular carcinoma: clinicopathological study of seven autopsy cases.

The clinical value of radiotherapy for hepatocellular carcinoma (total tumor dose: 50-70 Gy) was evaluated in seven autopsied patients with nine tumors. A partial response as defined by the WHO criteria for chemotherapy was observed in three tumors (33%). Progressive and marked shrinkage of the noncancerous liver tissue within the irradiated field was also observed in all cases. Histological examination revealed viable cancer cells in all cases. These results indicate that local radiotherapy applying 50-70 Gy achieved some clinical benefit, but was not capable of curing hepatocellular carcinoma.

Aged↗