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Biomedical subjects

S Aoki

Publications and source records attributed to S Aoki.

At least 289 records · Page 16Linked to original sources
PubMed1994

Sequence of the cellular T-DNA in the untransformed genome of Nicotiana glauca that is homologous to ORFs 13 and 14 of the Ri plasmid and analysis of its expression in genetic tumours of N. glauca x N. langsdorffii.

A region homologous to the TL-DNA of Agrobacterium rhizogenes was previously detected in the genome of untransformed Nicotiana glauca and designated cellular T-DNA (cT-DNA). Subsequently, part of this region was sequenced and two genes, which corresponded to rolB and rolC and were named NgrolB and NgrolC, were found. We have now sequenced a region of the cT-DNA other than the region that includes NgrolB and C and we have found two other open reading frames (ORFs), NgORF13 and NgORF14. These ORFs correspond to ORFs 13 and 14 of the TL-DNA of A. rhizogenes and exhibit a high degree of homology to these ORFs, without having a nonsense codon. We have not found any sequence homologous to rolD (ORF15). The two genes, NgORF13 and 14, as well as the NgrolB and C genes, are expressed in genetic tumors of hybrids between N. glauca and N. langsdorffii but not in leaf tissues of the hybrid.

Amino Acid Sequence↗
PubMed1994

Extracellular proteolytic activity of Cryptococcus neoformans.

Eight strains of Cryptococcus neoformans var. neoformans isolated from AIDS patients in the Infectious Disease Institute, University of Turin, Italy, were examined for growth and extracellular proteolytic activity in culture with solid and liquid media. All of the strains grew well on Yeast Carbon Base (YCB) agar medium supplemented with both 0.1% (w/v) bovine serum albumin (BSA) and 0.01% (w/v) polypeptone (Pp), and produced a clear proteolytic zone around their colonies, whereas they exhibited less growth and proteolytic activity on YCB medium supplemented with BSA alone. Strain #8 with a strong proteolytic activity was cultured in three different liquid media. Its growth was limited in YCB medium supplemented with 0.1% BSA, but was moderate in that with 0.01% Pp. Enhanced growth was supported by the addition of both BSA and Pp to the YCB medium. The relative value of the final cellular yields obtained with the above YCB-0.1% BSA, YCB-0.01% Pp and YCB-0.1% BSA-0.01% Pp media was approximately 1:10:20. In the culture with YCB medium containing both BSA and Pp, a rapid decrease in the amount of BSA was demonstrated by a spectrophotometric assay and gel electrophoresis of the culture supernatant after the log-to-stationary phase. The proteolytic activity in the culture supernatant became detectable after the log phase when tested with skim milk agarose plates. These results allowed us to conclude that Cr. neoformans var. neoformans is able to secrete protease and to utilize protein as a source of nitrogen.

Cryptococcus neoformans↗
PubMed1994

Molecular analysis of a patient with Beckwith-Wiedemann syndrome, rhabdomyosarcoma and renal cell carcinoma.

We described a patient with Beckwith-Wiedemann syndrome associated with rhabdomyosarcoma (RMS), and renal cell carcinoma (RCC). Karyotypes of peripheral lymphocytes and RMS cells were normal. DNA analyses showed maternal loss of heterozygosity (LOH) at 11p15 region in RMS but not in RCC. The insulin-like growth factor II gene (IGF2) was found to be expressed at a moderate level in RMS but not in RCC by in situ hybridization. Each of parental allele-derived IGF2 transcript was detected in RCC, while maternal allele-derived transcript was weak in RMS because of maternal LOH. These results suggest that (1) loss of imprinting (LOI) of IGF2 might be responsible for BWS, (2) on the other hand, LOI itself might not induce tumor occurrence in tissues where the control of tissue-specific expression of IGF2 is maintained, (3) increased expression of IGF2 due to maternal loss of a putative controller gene for IGF2 at 11p15 might predispose to sustaining tumorigenic mutations and tumor progression, (4) loss of a putative onco-suppressor gene at 11p15 might induce RMS occurrence. The cause of RCC was thought to be different from that of RMS.

Abdominal Neoplasms↗
PubMed1994

Cerebrospinal fluid levels of superoxide dismutases in neurological diseases detected by sensitive enzyme immunoassays.

We measured cerebrospinal fluid (CSF) levels of Cu/Zn superoxide dismutase (Cu/Zn SOD) and Mn superoxide dismutase (Mn SOD) using enzyme immunoassays in 196 neurological patients and 44 controls. The mean Cu/Zn SOD level was 55.8 +/- 27.6 (SD) ng/ml and the Mn SOD, 8.0 +/- 2.5 ng/ml in the controls. Cu/Zn SOD or Mn SOD levels showed neither age-nor sex-related differences in the controls. Both SODs were markedly elevated in cerebrovascular diseases, bacterial meningitis and encephalitis. Mn SOD alone was significantly elevated in neurodegenerative diseases. We compared SODs with CSF levels of neuron-specific enolase (NSE) and S-100b protein (S-100b) in cerebral infarction and bacterial meningitis. Both SODs were correlated with NSE and S-100b in patients with cerebral infarction, but not in those with bacterial meningitis. This means that elevations of SODs in CSF may not only be due to leakage from damaged nervous tissues, but also to the induction of SOD in lesions. We conclude that the mean SOD levels were elevated in various neurological diseases, and their varied magnitudes may be associated with the underlying diseases.

Adolescent↗
PubMed1994

Stimulus-onset dominance in the perception of binaural information.

With dichotic signals presented by headphone, stimulus-onset dominance (the 'precedence effect') was investigated for various types of binaural-processing-based percepts. The following three dichotic cues were considered: (1) inter-aural time delay (IATD, underlying the lateralization of the sound image), (2) inter-aural level difference (IALD, also underlying lateralization), and (3) inter-aural cross correlation (IACC, underlying the spaciousness of the sound image in terms of broadness/compactness). For all three cases, the degree of stimulus-onset dominance is estimated by one and the same experimental paradigm, which is essentially the same as used by Aoki and Houtgast [Hear. Res. 59, 25-30 (1992)]: When subdividing a brief stimulus in two parts of equal duration, a leading and a trailing part, in which the dichotic cue has opposite values, the over-all sensation is found to be dominated by the cue in the leading part. This dominance can be compensated by shortening the leading part (while keeping total signal duration constant), providing a quantitative measure for the onset dominance. The signals were octave-band filtered noise (center frequencies 500 or 2000 Hz) or 7-kHz low-pass filtered noise, and total signal duration was 5, 10, 20 or 40 ms. The results obtained for the four signal durations have been converted to a weighting function, representing the perceptual weight of the dichotic information as a function of time-after-signal-onset.(ABSTRACT TRUNCATED AT 250 WORDS)

Acoustic Stimulation↗
PubMed1994

Pharmacokinetics and pharmacodynamics of famotidine in children with gastroduodenal ulcers.

We treated 14 boys, six with gastric ulcers and eight with duodenal ulcers, to determine famotidine pharmacokinetics and its inhibition of gastric acid secretion (pharmacodynamics). Famotidine (1 mg/kg/day) was administered either intravenously or orally at a dose of 0.5 mg/kg twice a day (maximum: 40 mg/day). Blood samples were collected from all subjects and the intragastric pH monitored in eight. Pharmacokinetic parameters were calculated assuming a one-compartment model. Volume of distribution, elimination half-life, and area under the serum concentration-time curve were 1.52 +/- 0.37 l/kg, 2.29 +/- 0.38 h, and 1.14 +/- 0.32 ng.h/ml, respectively. The mean oral bioavailability of famotidine was 50.6%. Both intravenously and orally administered famotidine neutralized gastric acidity during sleep but failed to continuously maintain the intragastric pH > 5.0. All subjects' ulcers healed within 8 weeks. There were no side effects noted during famotidine treatment. Twice daily administration of 0.5 mg/kg famotidine for 8 weeks appears to be a tolerated and effective treatment of children with gastroduodenal ulcers.

Administration, Oral↗
PubMed1994

Evaluation of the correlation between in vivo and in vitro release. Effect of the force of contraction and food on drug release.

The effects of the force of contraction in the gastrointestinal (GI) tract and of food on drug release were investigated. Two dosage forms were administered orally to beagle dogs. Dosage form A was a matrix in which drug release was affected by the force of contraction in the GI tract, and dosage form B was not affected by the contraction force. The in vitro dissolution curves from dosage forms A and b using the paddle-beads method were similar to in vivo drug release, with the respective release of up to at least 50%. The in vitro release by means of the paddle-beads method was characterized by the in vivo drug release. The in vivo drug release profile from dosage form A was affected by food. A 1:1 relationship between in vivo and in vitro release was observed up to 6 h in those dogs under the fed condition, but only up to 2.5 h in those under the fasted condition. In the earlier stage of oral administration there was no difference in drug release profile between dogs of the fed and fasted conditions; however, the drug release rate in the fed condition was faster than that in the fasted condition 2-4 h after administration. It was thus assumed that in the fed condition, drug release from dosage form A was affected by gastro-duodenal transit time or by the different environment in the distal parts of the GI tract rather than by the force of contraction.

Administration, Oral↗
PubMed1994

Marine natural products. XXXIV. Trisindoline, a new antibiotic indole trimer, produced by a bacterium of Vibrio sp. separated from the marine sponge Hyrtios altum.

A new antibiotic indole trimer named trisindoline (1) was isolated, together with a known dioxopiperazine brevianamide F (2), from the culture of a bacterium of Vibrio sp., which was separated from the Okinawan marine sponge Hyrtios altum. The structure of trisindoline (1) has been determined on the bases of physicochemical evidence and chemical synthesis.

Animals↗
PubMed1994

K(+)-linked release of oxidized glutathione induced by tert-butyl hydroperoxide in perfused rat liver is independent of lipid peroxidation and cell death.

The tert-butyl hydroperoxide (BHP)-induced release of oxidized glutathione (GSSG) and K+ was studied in relation to lipid peroxidation and cell death using isolated perfused rat livers. Infusion of BHP into the perfused liver resulted in an early and simultaneous release of GSSG and K+ and a sustained release of thiobarbituric-acid-reactive substances (TBARS) into the effluent perfusate, which was followed by further prenecrotic leakage of K+ followed by lactic dehydrogenase (LDH). These actions of BHP were not significantly affected by cutting or ligating the bile duct, and they were potentiated by omitting Ca2+ from the perfusion medium. Co-infusion of desferrioxamine, propyl gallate and diethyldithiocarbamate suppressed TBARS release as well as the later leakage of K+ and LDH. Desferrioxamine was also effective under Ca(2+)-free conditions. N,N'-diphenyl-p-phenylenediamine inhibited TBARS release, but it was not protective against cell death, although there was some delay. The action of dithiothreitol was only moderate. On the other hand, leakage of TBARS, K+ (prenecrotic) and LDH was enhanced by cysteamine and beta-mercaptoethanol and most markedly enhanced by ferrous iron. However, none of these agents markedly affected the early release of GSSG and K+. These observations, which support our previous findings, suggest that the early and coupled sinusoidal efflux of GSSG and K+ caused by BHP is independent of lipid peroxidation and cell death and that they represent a physiological mechanism of GSSG release. The results also suggest that lipid peroxidation is not the sole cause of BHP-induced cell death.

Animals↗
PubMed1994

[Bacteriological and clinical studies on cefozopran in pediatric field].

We carried out clinical studies on cefozopran (CZOP, SCE-2787). The results are summarized as follows. Treatment with CZOP was made in 17 cases of pediatric bacterial infections including 2 cases of purulent tonsillitis, 11 cases of acute pneumonia and 2 cases each of urinary tract infections and enteritis. Results obtained were excellent in 12 cases, good in 2 cases, fair in 2 cases and poor in 1 case. All of 9 isolated bacteria were eradicated by the treatment. As side effects and laboratory test results, rash was observed in one case and transient increase of platelets in one case, slight increase of eosinophil in 2 cases and transient elevation of GPT and GOT.GPT in one case.

Bacteria↗
PubMed1994

[Bacteriological and clinical studies of biapenem (L-627) in pediatric field].

We have carried out bacteriological and clinical studies on L-627. The results are summarized as follows. Treatment with L-627 was made in 14 cases of pediatric bacterial infections including 5 cases of pneumonia and 2 cases each of tonsillitis, urinary tract infection and one case each of colitis, and phlegmon. Results obtained were excellent in 11 cases, good in 2 cases and poor in one case. The bacteriological effect of L-627 was excellent, all causative organisms (Staphylococcus aureus one strain, Streptococcus pyogenes 2 strains, Streptococcus pneumoniae 3 strains, Escherichia coli 3 strains, Haemophilus influenzae one strain, Haemophilus parainfluenzae one strain) were eradicated. No significant side effects due to the drug were observed in any cases, except 2 cases each of elevated eosinophil counts and elevated platelet counts.

Bacteria↗
PubMed1994

[Efficacy of benzimidazole-type drugs on alveolar echinococcosis (AE)].

AE patients can be cured only by complete excision of the lesions. In Europe and the United States, however, benzimidazole-type drugs have been reported to be effective. We treated 37 patients (20 males and 17 females, mean age of 45.9 years) with mebendazole (MBZ) (n = 17) or albendazole (ABZ) (n = 20) according to the WHO chemotherapy protocol, and compared adverse reactions, drug concentrations, serological parameters, and measurable lesions by CT scan and/or X-ray examination. In the MBZ group, serological parameters were unaffected. One patient each had hepatic disorder and alopecia (12%), and 5 lesions in the liver and 3 in the lung gradually increased in size (105% in 1 year, 112% in 2 years), and showed NC (no response) in 6, PD (progressive disease) in 2. One case of released biliary obstruction were judged as PR (partial response) (Response rate: 11.1%). In the ABZ group, no adverse reactions were found and ELISA level decreased significantly in 10 out of 12 patients. One lesion in the liver, 3 in the lung, 1 in the chest wall and 1 in the retropancreatic region reduced in size significantly (Mean: 56%) (PR 3, NC 3; Response rate: 50.0%). ABZ was safer and more effective than MBZ.

Adult↗