Biomedical subjects
Publications and source records attributed to T Toyomasu.
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The drimane sesquiterpenes, (+)-albicanol (2) and (+)-albicanyl acetate (3), were synthesized from an optically active bicyclic diol [(+)-1] that had been obtained via the recently developed optical resolution of a general synthetic intermediate for drimane sesquiterpenes. The crucial step in the previous syntheses was markedly improved by the modified Wittig methylenation of a silyloxy ketone (7). The high overall yield (77% in 4 or 5 steps from (+)-1) by this total synthesis makes it possible to synthesize the other biologically active drimane sesquiterpenes.
We report here the nucleotide sequence of a full-length cDNA encoding ent-kaurene synthase that was isolated by a reverse-transcription polymerase chain reaction from Gibberella fujikuroi (Gcps/ks). This cDNA encodes 952 amino acid residues with a relative molecular mass of 107 kDa. The sequence similarity between Gcps/ks and ent-kaurene synthase of the gibberellin A1-producing fungus, Phaeosphaeria sp. L487, is very high, suggesting that Gcps/ks is also a bifunctional diterpene cyclase. Its recombinant protein expressed in Escherichia coli converted geranylgeranyl diphosphate to copalyl diphosphate and ent-kaurene.
The thermodynamic equations of the formation of and adsorption at interfaces were derived for a three-phase system having a floating lens with curved interfaces. The surface excess quantities were defined both in the H convention based on the two dividing surfaces and in the P convention based on the four dividing surfaces. Their physical significance and utilities were discussed. The equations were simplified to be applicable to the three-component systems with the plane A/W interface and a relatively large size of lens, such as the air/water/long-chain alcohol systems. The formulation and geometrical consideration of the two conventions with respect to this simple cases revealed that the H convention introduces the distance between the two dividing surfaces and the P convention introduces three kinds of distances between the four dividing surfaces including a kind of thickness of the reference oil lens phase in the A/W interfacial region. Furthermore, the general equations were simplified to be applicable to four-component systems such as the air/oil solution of a surface-active substance/water or the air/oil/aqueous solution of a surfactant with a floating oil lens. Copyright 1999 Academic Press.
Several reports indicate that the mechanism of resistance to cisplatin is multifactorial. However, DNA damage tolerance appears to be the more significant mechanism. It is clear that resistance in general is a major clinical concern, and a number of approaches have been taken to circumvent this clinical impediment. One approach is through analog development, and we have identified 1,2-diaminocyclohexane-diacetatodichloro-platinum(IV) as an analog with activity in cisplatin resistance. The activity is greatest against ovarian tumor cell lines where the latent, non-inducible wild-type p53 function can be reactivated by the analog. This functional activation of p53 also corresponds to a reduced threshold for tolerance to DNA damage induced by the analog. Interestingly, cell lines with mutant or null p53 are cross-resistant to the analog. The data indicate that cisplatin resistance due to an increase in DNA damage tolerance can arise through a loss of p53 function, and that functional activation of latent wild-type p53 by the analog facilitates cell death and circumvents this resistance mechanism.
Extract of Coprinus disseminatus (pers. Fr.) (C. disseminatus) culture broth (EDCB) inhibits proliferation and induces apoptosis in the human cervical carcinoma cells at 5 microg/ml. To determine whether the cell death induced by the EDCB recruits caspases or not, one of the exclusive pathways in cell death, we examined caspase-3 activity in this cell death process. The activity of caspase-3 was remarkably increased when the cell was treated with EDCB, and this activity was nullified by Z-VAD-FMK, a well known caspase-3 inhibitor. From these results, we would expect the EDCB to contain substances with the ability to induce apoptosis in the human cervical carcinoma cells. The extent of the EDCB induced apoptosis is cell line-dependent.
Germination of lettuce (Lactuca sativa L.) seed is regulated by phytochrome. The requirement for red light is circumvented by the application of gibberellin (GA). We have previously shown that the endogenous content of GA1, the main bioactive GA in lettuce seeds, increases after red-light treatment. To clarify which step of GA1 synthesis is regulated by phytochrome, cDNAs encoding GA 20-oxidases (Ls20ox1 and Ls20ox2, for L. sativa GA 20-oxidase) and 3beta-hydroxylases (Ls3h1 and Ls3h2 for L. sativa GA 3beta-hydroxylase) were isolated from lettuce seeds by reverse-transcription polymerase chain reaction. Functional analysis of recombinant proteins expressed in Escherichia coli confirmed that the Ls20ox and Ls3h encode GA 20-oxidases and 3beta-hydroxylases, respectively. Northern-blot analysis showed that Ls3h1 expression was dramatically induced by red-light treatment within 2 h, and that this effect was canceled by a subsequent far-red-light treatment. Ls3h2 mRNA was not detected in seeds that had been allowed to imbibe under any light conditions. Expression of the two Ls20ox genes was induced by initial imbibition alone in the dark. The level of Ls20ox2 mRNA decreased after the red-light treatment, whereas that of Ls20ox1 was unaffected by light. These results suggest that red light promotes GA1 synthesis in lettuce seeds by inducing Ls3h1 expression via phytochrome action.
The formation of the water + ethanol mixture/air surface was studied by measuring the surface tension as a function of temperature and the mole fraction of ethanol in the mixture. The surface composition, the entropy Deltas , and energy Deltau of surface formation were evaluated by adopting the thermodynamic equations. It was shown that the surface was enriched in ethanol molecules compared with the bulk solution. The values of Deltas and Deltau were examined closely by estimating the contribution from the nonideal mixing in the bulk solution and that at the surface to Deltas and Deltau . It was concluded that the surface formation is driven by entropy at lower x 2 and by energy at higher x 2 , respectively, and that the surface formation becomes more energetically favorable with rising temperature.
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To define the characteristics of colorectal cancer with regard to site distribution, age, and sex, due to the significantly increased incidence of colorectal cancer in Japan, we investigated 1,205 Japanese patients with colorectal cancer between 1975 and 1994. When we compared site distribution for age and sex in the entire 20-year period, tumors in the proximal colon were more frequent in elderly patients than in young ones (p < 0.05); this tendency was true only for females (p < 0.01), but not for males. The increased incidence of proximal colon cancer in elderly patients was also found in the second 10-year period (p < 0.05). Because elderly patients are characterized by an increasingly high incidence of proximal colon cancer in recent years, more concerted efforts for the early detection of proximal colon cancer, particularly in the elderly, are called for.
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Two cDNA clones, cLRG5 and cLRG11, that respond to gibberellin (GA) were isolated from seeds of photoblastic lettuce (Lectuca sativa L. cv. Grand Rapids) by differential screening. Northern blot analysis indicated that the levels of LRG5 and LRG11 mRNAs were raised to slightly higher levels 10 h after the start of GA treatment and the levels were maintained at least for further 8 h, while those in the control seeds gradually decreased. Red light irradiation had effects similar to GA treatment. The cLRG5 insert encodes a putative polypeptide of 380 amino acids that is highly homologous to alcohol dehydrogenases from several higher plants. With regard to the cLRG11 insert, no homologous gene has been reported.
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Neurological, computed tomography (CT) and magnetic resonance imaging (MRI) findings were recorded from 13 patients with Japanese encephalitis (JE) in the Kurume region diagnosed by serological criteria. The patients averaged 63 years of age, and 5 were older than 70 years. The serological data mostly indicated a primary response. Hemiplegia and tetraplegia were common, together with extrapyramidal signs. A few cases had a stroke-like onset and cerebral haemorrhage during the course of JE. CT and MRI in 7 cases revealed abnormalities in the thalamus and basal ganglia including the putamen. The CT and MRI findings from the acute stage to the convalescent stage were considered to be characteristic of JE.
The bacteria in 37 stones obtained from 37 patients with urinary stone diseases, that is, 11 renal stones (containing 2 staghorn calculi), 21 ureteral stones, 4 bladder stones and 1 urethral stone, were studied, according to the Nemoy & Stamey's method. The stones were collected by partial nephrectomy (1 case), nephrolithotomy (1 case), pyelolithotomy (1 case), percutaneous nephrolithotripsy (PNL) (6 cases), 12 ureterolithotomies, transurethral ureterolithotripsy (2 cases), cystolithotripsies (4 cases) and spontaneous deliveries (10 cases). According to a stone analysis by infrared spectrophotometer revealed 30 were noninfection stones (81.1%) and 7 infection stones (18.9%). Of these 37 stones, 5 stones (13.5% of 11 stones) had bacteria within them. These stones consisted of 4 infection stones (57.1% of all infection stones) and 1 noninfection stone (3.3% of all noninfection stones). Out of 4 patients having bacteria within their stones, urine culture of whom were carried out before stones were collected, only one patient (25%) had the same species of bacterium (E. coli) both within the stone and in urine. The E. coli within the stone and that in urine, however, showed quite different reactions to some antibiotics. The fact that all organisms within stones cannot be detected by urine culture before collecting stones of the patients in our present study, suggests that patients undergoing endourological surgery, such as extracorporeal shock wave lithotripsy and PNL, may have a risk of complications, such as severe urinary tract infection and urosepsis, if the possibility of the presence of organisms within stones is not taken into consideration.
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Six hundred and eight red cell hemolysates were screened for glutamate-pyruvate transaminase (GPT) by means of isoelectric focusing. Two new variant phenotypes were detected, neither of which could be distinguished from GPT2-1 and GPT2 by conventional starch gel electrophoresis. The two types were considered to correspond to GPT2B-1 and GPT2A-2C reported previously in samples of European origin.
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