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Biomedical subjects

E Imai

Publications and source records attributed to E Imai.

At least 145 records · Page 8Linked to original sources
PubMed1989

Facile synthesis of 8-benzoylthio-2,6-methano-3-benzazocines and 3-benzoylthiomorphinans having small-ring substituents.

Synthesis of 3-cyclopropylmethyl-, 3-cyclobutylmethyl-, and 3-methyl-8-benzoylthio-2,6-methano-3-benzazocines (1j-l) was performed by regio-selective chlorosulfonation of non-narcotic 8-deoxy derivatives (1a-c) followed by reduction and benzoylation. 3-Benzoylthiomorphinans (2h-j) were also obtained by the same method. Compounds having small-ring substituents (1k, 1l, 2i, 2j) were found to be weak but pure mu- and delta-opioid antagonists. The analgetic activity of 1k was almost equal to that of pentazocine.

Analgesics↗
PubMed1988

Albumin gene transcription is enhanced in liver of nephrotic rats.

The level of albumin mRNA and the transcription rate of the albumin gene were studied in the liver of control rats and rats with nephrosis induced by injection of the aminonucleoside of puromycin. Total RNA was extracted from liver by the guanidium thiocyanate method. The albumin mRNA level was measured by cDNA-RNA dot-blot hybridization, and the transcription rate of the albumin gene was measured by the "run-on" transcription assay using isolated nuclei. Urinary protein excretion in nephrotic rats was significantly higher than in control rats (258 +/- 132 vs. 12 +/- 2 mg/day), and the serum albumin concentration in nephrotic rats was significantly lower. There was no difference in body weight, liver weight, serum creatinine, or urea nitrogen between the two groups. Both the level of albumin mRNA and the transcription rate of the albumin gene in the nephrotic liver were about twice as high as those in the control liver. There was no difference in the level of beta-actin mRNA between the two groups. Northern blot analysis showed that both putative precursor RNA and the mature form of albumin mRNA were increased in nephrotic rats. We conclude that albumin synthesis is increased in the liver of nephrotic rats and a transcriptional process is responsible for this increase.

Actins↗
PubMed1987

Effects of chronic renal failure on the regulation of pyruvate kinase.

The effects of chronic renal failure on the enzyme activity of pyruvate kinase and the mRNA level of this enzyme were studied in 7 out of 8 nephrectomized rats. The mRNA level was measured by RNA-DNA dot blot hybridization, using cloned pyruvate kinase cDNA as hybridized probe. Neither the activity of M1-type pyruvate kinase nor the level of this enzyme in rat gastrocnemius muscle was affected by chronic renal failure, whereas L-type pyruvate kinase enzyme activity in uremic rat liver was lower than that in control at both fasted and refed states. The levels of L-type pyruvate kinase mRNA were not different between two groups at the fasted state. Induction of L-type pyruvate kinase mRNA after high carbohydrate diet refeeding was suppressed proportionally to the severity of chronic renal failure, which was expressed by the serum creatinine concentrations (r = -.876, P less than .005). These results indicate that the suppression of L-type pyruvate kinase activity in uremia was partly reflected by the decreased accumulation of this enzyme mRNA. There was a significantly negative correlation between L-type pyruvate kinase mRNA levels and plasma glucagon/insulin ratios (r = -.719, P less than .05). Hyperglucagonemia in uremia might play a major role in this suppression.

Animals↗
PubMed1986

Plasma concentration and peritoneal clearance of oxalate in patients on continuous ambulatory peritoneal dialysis (CAPD).

Accumulation of oxalate, resulting in high plasma levels, is a common finding in end-stage renal disease. We investigated plasma concentration and peritoneal clearance of oxalate in 14 patients on continuous ambulatory peritoneal dialysis. The plasma oxalate levels in these patients (30.2 +/- 11.2 mumol/l) were as high as those in hemodialysis patients before dialysis (31.9 +/- 11.1 mumol/l). There was a significant correlation between plasma oxalate and urea nitrogen appearance (UNA). Dietary protein seems to be an important oxalate source in these patients, because the UNA reflects protein intake in stable patients. The mean peritoneal oxalate clearance was 6.64 +/- 1.56 l/day, close to the creatinine clearance. These results suggest that the plasma oxalate levels in CAPD patients may be sufficiently high to induce calcium oxalate deposition, and that methods of increasing oxalate removal and reducing oxalate burden are necessary for CAPD patients.

Adolescent↗
PubMed1985

Novel nonnarcotic analgesics with an improved therapeutic ratio. Structure-activity relationships of 8-(methylthio)- and 8-(acylthio)-1,2,3,4,5,6-hexahydro-2,6-methano-3-benzazocines.

Conversion of the 8-phenolic 1,2,3,4,5,6-hexahydro-2,6-methano-3-benzazocines to the corresponding 8-thiophenolic analogues was achieved by three different routes. Diazotization of 8-amino-2,6-methano-3-benzazocine (2) followed by the reaction with CH3SNa afforded 8-(methylthio)-1,2,3,4,5,6-hexahydro-2,6-methano-3-benzazocine (3). Another route using Grewe cyclization was also examined for the synthesis of 3. As the most effective route, Newman-Kwart rearrangement of benzazocines was selected and closely investigated. 8-(N,N-Dimethylthiocarbamoyl)oxy derivatives (6a-e) rearranged to 8-(N,N-dimethylcarbamoyl)thio derivatives (7a-e) in good yields. Reductive cleavage of 7a-e and subsequent methylation or acylations gave the title compounds (3, 8-24). Although analgesic activities of sulfur-containing benzazocines decreased compared to the corresponding hydroxy compounds, the N-methyl derivative (S-metazocine, 8) showed potent analgesic activity.

Acylation↗
PubMed1983

(1,2-Diphenylethyl) piperazines as potent opiate-like analgesics; the unusual relationships between stereoselectivity and affinity to opioid receptor.

A series of novel diphenylethylpiperazines were synthesized, and analgesic activities and opioid receptor interactions were evaluated. Analgesic activity of S(+) enantiomer of 1-cyclohexyl analogues (I-C6) was as potent as morphine. This compound showed narcotic properties. Racemate of I-C6 demonstrated the most potent analgesic activities among the enantiomorphic pairs. The R(-) isomer and (-) spa, NN-dimethyl-1, 2-diphenylethylamine, had mu-agonist like character. The S(+) isomer possessed high affinity for all types of the receptor, especially favorable for delta and kappa, in the different manner from opiate-like analgesics. It is conceivable that opioid receptor has various subsites, and this S(+) enantiomer alter the conformation of the receptor.

Analgesia↗
PubMed1983

[Effects of cianidanol (KB-53) on experimental liver injury in mice--histopathological, histochemical and enzyme-histochemical studies].

Protective effects of KB-53 on acute liver injury induced by carbon tetrachloride (CCl4) and 1-naphtylisothiocyanate (ANIT) in mice was investigated by means of histopathological, histochemical and enzymehistochemical examinations. Diffuse centrilobular necrosis, ballooning degeneration of hepatocytes and hemorrhage were markedly observed in the livers of the mice one to three days after a subcutaneous injection of CCl4. On the other hand, in the livers of KB-53 pretreated mice, forcal necrosis was observed and inflammatory cells had already infiltrated one day after CCl4-intoxication. Three days later, remarkable development of absorbent granulation tissues with syncytium and hepatocytic mitosis was observed. Furthermore, a number of PAS positive materials such as mucopolysaccharides and mucoproteins were detected in the livers of KB-53 pretreated mice. KB-53 inhibited the disappearance of glucose-6-phosphatase (G-6-Pase) in the liver after CCl4-intoxication and the rise of alkaline phosphatase (Al-Pase) in the liver after ANIT-intoxication. In addition, KB-53 inhibited the rise of Al-Pase and total bilirubin in the serum of mice after CCl4 and ANIT-intoxication. All these findings suggest that KB-53 protects liver against the morphological and functional changes, and it potentiates the proliferative and regenerative activity of the liver impaired with CCl4 and ANIT.

1-Naphthylisothiocyanate↗
PubMed1983

[Effect of cianidanol (KB-53) on delayed skin reactions in mice compromised by carbon tetrachloride and 1-naphthylisothiocyanate].

A study was carried out to investigate the influence of 3 kinds of hepatotoxic agents on the peripheral blood leucocyte population, the splenocyte population and the delayed type hypersensitivity (DTH) in mice. These parameters were not affected by the intraperitoneal injection of D-galactosamine (Gal). The intensity of picryl chloride induced DTH (PC-DTH) in mice was significantly lowered with the administration of carbon tetrachloride (CCl4) and 1-naphtylisothiocyanate (ANIT) in a dose-dependent manner after the mice were sensitized to picryl chloride (PC) from one to three days after the subcutaneous injection of CCl4 and ANIT. However the peripheral blood leucocyte population and splenocyte population were not affected by these chemicals. The lowering effect of CCl4 and ANIT on PC-DTH was somewhat weakened when PC sensitization was performed seven days after the injection of CCl4 and ANIT. No lowering effect was observed when PC sensitization was performed fourteen days after the injection of CCl4 and ANIT. The intensity of PPD induced DTH (PPD-DTH) was also lowered by the administration of CCl4 and ANIT when the sensitization to tubercle bacilli was performed three days after the injection of CCl4 and ANIT. Cianidanol (KB-53) prevented the decrease of PC-DTH and PPD-DTH in the mice injected with CCl4 and ANIT in a dose-dependent manner, but did not affect DTH in normal mice. So it seems that KB-53 has an immunostimulating effect on decreased cellular immunity.

1-Naphthylisothiocyanate↗
PubMedDate not supplied

Contribution of temperature gradient to aggregation of thermal heterocopolymers of amino acids in aqueous milieu.

We prepared thermal heterocopolymers of amino acids, aspartic acid and proline, and solubilized them in distilled water at boiling temperature. The resulting suspension was then cooled down while controlling the cooling rate. The maximum growth of phase-separated microspheres was found to occur at a finite, nonzero cooling rate. Temperature-gradient controlled growth of these microspheres indicates that aggregation of thermal heterocopolymers of amino acids in their aqueous milieu is irreversible. In view of the fact that evolutionary process is an indication of lasting physical irreversibility, thermal heterocopolymers of amino acids were shown to have an evolutionary significance in maintaining the capacity of irreversibility lasting over at least several hours.

Aspartic Acid↗