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Biomedical subjects

T Furuya

Publications and source records attributed to T Furuya.

At least 199 records · Page 11Linked to original sources
PubMed1991

A simple experimental model of total hepatectomy, hepatic ischemia and extrahepatic portal obstruction in rats using splenic transposition.

The objective of this study was to develop an easy and simple experimental rat model of total hepatectomy, hepatic ischemia and extrahepatic portal obstruction. The first operation involved transposing the spleen with its scarified capsule in a subcutaneous pouch to produce portasystemic anastomosis. Total hepatectomy was easily performed in a lobe-by-lobe fashion 2 weeks following the first stage operation. Anhepatic rats receiving a glucose infusion survived for about 10 hours and all died of acute hepatic failure. Hepatic support systems can be accurately evaluated in this anhepatic rat model because of its uniformity. Sixty minutes of hepatic ischemia was able to be performed in rats with a transposed spleen for a portasystemic shunt and no complicated or technically involved procedure was required for the ischemic model. No rats died due to technical difficulties, suggesting the reliability and reproducibility of this ischemic model. An animal model resembling extrahepatic portal vein obstruction was also obtained by ligation of the portal vein; a simple maneuver which was able to produce collateral veins to the liver and cavernous transformation, as similarly seen in clinical patients with extrahepatic portal obstruction. Because these 3 animal models were so easily achieved in the rat, and since the changes in hepatic function and formation of the collaterals to the liver after portal vein occlusion are still poorly understood, this model should prove valuable for future study.

Animals↗
PubMed1991

Effect of methyl esterification of isoglutamine residue in 6-O-acylated muramyl dipeptides on expression of immunopharmacological activities.

The effect of methyl esterification of the isoglutamine residue in 6-O-acylated muramyl dipeptide (MDP) on some biological activities was investigated. Methyl esterification influenced more or less the expression of all activities tested. The adjuvant and colony stimulating factor (CSF)-inducing activities of 6-O-acylated MDP analogs carrying a 3-hexadecanoyloxytetradecanoyl [C14-O-(C16)] group were stronger than those of the corresponding analogs carrying a 2-tetradecylhexadecanoyl (B30) group. Macrophage activation, i.e. induction of tumor necrosis factor (TNF) and promotion of phagocytosis, by 6-O-C14-O-(C16)-MDP methyl esters was weaker.

Acetylmuramyl-Alanyl-Isoglutamine↗
PubMed1991

Identification of feline immunodeficiency virus rev gene activity.

We constructed 16 deletion mutants from an infectious molecular clone of feline immunodeficiency virus (FIV) and a reporter plasmid carrying the bacterial chloramphenicol acetyltransferase (CAT) gene to identify the rev transactivator activity of the virus. Cotransfections of various mutants and the rev reporter clone bearing a portion of FIV env in addition to the CAT gene revealed that the sequence important for the augmentation of CAT production was located in three separate parts of the virus genome. This enhancement was FIV specific in that the human retrovirus rev and rex gene products did not activate the reporter. The phenotypic properties of an FIV proviral mutant containing a small deletion in the genome were similar to those of rev mutants derived from primate immunodeficiency viruses. These results indicate that FIV, like the other lentiviruses, contains the rev gene in its genome.

Animals↗
PubMed1991

Ultrastructural studies of collagen fibers of the cornea and sclera by a quick-freezing and deep-etching method.

The ultrastructure of collagen fibers of the cornea and sclera of rabbits was studied by a newly developed quick-freezing and deep-etching method. An isopentane-propane mixture (-193 degrees C) cooled in liquid nitrogen was used for quick-freezing of the tissues. The frozen tissues were fractured in nitrogen, deeply etched and shadowed with platinum and carbon. Corneal collagen fibers were observed to be longitudinally arranged and separated by moderately wide interfibrillar spaces. Interconnecting filaments were three-dimensionally radiating between the collagen fibers, which were 40.6 +/- 5.0 nm in diameter and 42.0 +/- 2.8 nm in periodicity. In contrast, scleral collagen fibers were compactly organized, with few interconnecting filaments. Five kinds of striations were clearly observed on the collagen fibers, which were 217.3 +/- 50 nm in diameter and 67.5 +/- 1.4 nm in major periodicity. These striations could hardly be observed in the fractured scleral collagen fibers. The present study reveals the ultrastructural differences between corneal and scleral collagen fibers through the use of a quick-freezing and deep-etching method.

Animals↗
PubMed1991

Synthesis, resolution, and renal vasodilation activity of novel DA1 agonists: 4-(3,4-dihydroxyphenyl)-1,2,3,4-tetrahydroisoquinoline derivatives.

7,8-Dihydroxy-4-(3,4-dihydroxyphenyl)-1,2,3,4-tetrahydroisoquinoline (1) and 4-(3,4-dihydroxyphenyl)-7-hydroxy-8-methyl-1,2,3, 4-tetrahydroisoquinoline (2) are potent renal vasodilators which selectively stimulate DA1 (peripheral dopamine receptor-1) receptors. Especially, (S)-(-)-1 is the most potent. Its DA1 agonist activity is about 10 times stronger than dopamine for increasing renal blood flow in anesthetized dogs. The renal and cardiovascular effects of (S)-(-)-1 may be suitable for the treatment of patients with renal insufficiency, heart failure and hypertension.

Animals↗
PubMed1991

[Effects of tissue cultured ginseng on the function of the stomach and small intestine].

Effects of tissue cultured ginseng on the function of the stomach and small intestine were compared with those of cultivated ginseng. Fifty percent ethanol extracts of the tissue cultured and cultivated ginseng stimulated gastrointestinal propulsion in mice. The tissue cultured ginseng also inhibited ulcer formation induced by water immersion and restraint stress, and ligature of the pylorus. In contrast, the cultivated ginseng showed no such inhibitory action.

Animals↗
PubMed1991

[Effects of tissue cultured ginseng on gastric secretion and pepsin activity].

Effects of the tissue cultured and cultivated ginseng on gastric secretion and pepsin activity were investigated. Fifty percent ethanol extracts of both cultured and cultivated ginsengs reduced gastric secretion and acid output in pylorus-ligated rats. They did not affect pepsin activity. The tissue cultured ginseng inhibited histamine and pentagastrin-induced acid secretion in rats, whereas the cultivated ginseng showed no such effect. They also suppressed acid secretion induced by 2-deoxy-D-glucose and baclofen [beta-(p-chlorophenyl)-gamma-aminobutyric acid], which are known to stimulate gastric acid secretion via the central nervous system. However, they had no effect on acid secretion induced by vagal stimulation. These results suggest that both tissue cultured and cultivated ginsengs may have an inhibitory effect on gastric secretion. The effect seems to be due to the inhibition of acid secretion via the central nervous system.

Animals↗
PubMed1991

[Studies on collagenase inhibitors. IV. Inhibitors of bacterial collagenase in Coptidis rhizoma].

A hot aqueous extract of Coptidis Rhizoma had an inhibitory effect on the bacterial collagenase from Clostridium histolyticum. Active principles were isolated by silica gel column chromatography from the CHCl3 extract. Consequently, two inhibitors obtained were identified with the chloride of berberine and coptisine. The concentrations of the berberine and coptisine in the assay mixture to give 50% inhibition (IC50) were 0.73 mM and 0.16 mM, respectively. The type of inhibition by coptisine chloride was shown to be a mixture type from Lineweaver-Burk plots. Tetrahydroberberine, a reduction product of berberine chloride, had no inhibitory effect. This result suggests that the quaternary nitrogen of the alkaloids plays an important role in inhibitory activity.

Berberine↗
PubMed1991

[Characteristics on staining of leukocytes in experimental animals].

The staining characteristics of the peripheral blood cells from mouse, rat, guinea pig, rabbit, dog, marmoset and monkey were studied. In marmoset, it is easy to distinguish neutrophils from eosinophils by using the phosphate-buffered solution of pH 5 or 6. It was found in the special staining methods that neutrophil granules showed intense peroxidase and Sudan black B reactions in marmoset in comparison with those in the other species of experimental animals. Neutrophil granules rabbit was, however, intensely stained with esterase and acid phosphatase.

Animals↗
PubMed1991

Chronic toxicity of 2,4,6-tri-tert-butylphenol in rats.

In order to study the chronic toxicity of 2, 4, 6-tri-tert-butylphenol (TTBP), groups of 40 Slc: Wistar rats of either sex were fed diet containing 0, 30, 100, 300 or 1000 ppm of TTBP for up to 24 months. Hematological, biochemical and histopathological examinations performed periodically revealed slight microcytic anemia, changes in some biochemical parameters relating to liver function and focal necrosis of liver cells following TTBP administration, and these changes observed in females were severer than those in males. No neoplastic responses following TTBP administration were noted. Noticeable changes were not observed in the 30 ppm group throughout the experimental period. Thus, it was concluded that TTBP causes liver injury characterized by focal necrosis with microcytic anemia and elevations of serum phospholipids and cholesterol levels presumably occurring as secondary effects following the liver injury.

Anemia↗
PubMed1991

[A case of angiomatous meningioma near the geniculate ganglion].

A 57-year-old male was admitted with pulsatile tinnitus and hearing disturbance of the right ear and right peripheral facial palsy. Otological examination revealed a pulsatile red mass in his right ear and right conductive hearing disturbance. CT and MRI showed the mass lesion at his right middle fossa near the geniculate ganglion. Right external carotid angiogram disclosed a tumor stain fed by the middle meningeal artery. The tumor was removed via a combination of subtemporal and transmastoidal approaches. Histologically, this tumor was diagnosed as angiomatous meningioma partly with meningotheliomatous meningioma. Meningioma in this region is very rare. We discussed its clinical and radiological characteristics in comparison with chemodectoma and facial neurinoma at the geniculate ganglion.

Angiography↗
PubMed1991

Hepatic hemodynamics and functions in extrahepatic portal obstruction in the rat with liver cirrhosis.

Portal vein obstruction due to a thrombus may be encountered in liver cirrhosis. However, the effect of portal vein obstruction on hepatic hemodynamics and functions, and on collateral formation has not been clear in liver cirrhosis. To rectify this, the cirrhotic rat model with portal vein ligation was evaluated. In addition to the early recovery of hepatic blood flow, the reduction in hepatic blood flow after portal vein ligation was less in the cirrhotic rat than in the normal rat. The portogram showed that, in addition to hepato-fugal collaterals, hepato-petal collaterals developed well and early in the cirrhotic rat as compared with the normal rat. Although mitochondrial functions before portal vein ligation deteriorated in the cirrhotic rat, the decrease after portal vein ligation was less, and the recovery of function was earlier in the cirrhotic than the normal rat. The influence of portal vein obstruction on hepatic hemodynamics and functions in the cirrhotic rat was less than in the normal rat, due to earlier and significant formation of hepato-petal collaterals.

Animals↗
PubMed1990

Biotransformation of digitoxigenin by ginseng hairy root cultures.

Five new compounds (three esters and two glycosides) and seven previously reported compounds were isolated as biotransformation products of digitoxigenin by ginseng hairy root cultures. The new esters and glycosides were elucidated as digitoxigenin stearate, digitoxigenin palmitate, digitoxigenin myristate, 3-epidigitoxigenin beta-D-gentiobioside and digitoxigenin beta-D-sophoroside using 1H and 13CNMR and FAB mass spectral data. Biotransformations involving esterification (of stearic acid, palmitic acid, myristic acid and lauric acid) and glycosylation (of gentiobiose and sophorose) of digitoxigenin have been demonstrated for the first time in the plant cell and tissue cultures. The hairy roots showed high glycosylation ability to the digitoxigenin molecule.

Angiotensinogen↗
PubMed1990

Onset of compensatory hypertrophy of interstitial tissue and Leydig cells in rats hemicastrated around the time of puberty.

When rats were unilaterally castrated at 20, 30, and 40 days of age, only those rats hemicastrated at 40 days showed compensatory hypertrophy of the interstitial tissue and Leydig cells when killed 30 days after hemicastration. At the time of death, volume densities of interstitial tissue, Leydig cells, and vascular components were greater in 70-day-old hemicastrated rats than in intact rats of the same age. The total number of Leydig cells per testis in hemicastrated and intact rats was always the same at any age. Estimated Leydig cell volume in 70-day-old rats was twice that in intact rats. By contrast, the testes of 50- and 60-day-old rats at the time of death displayed essentially the same morphological features, regardless of whether animals were hemicastrated. The concentration of plasma testosterone was higher in 50-day-old controls than in hemicastrated rats. Seventy-day-old hemicastrated rats showed higher levels of plasma testosterone than controls. The level of plasma dihydrotestosterone in 60- and 70-day-old hemicastrated rats exceeded that in the controls. A significant increase in follicle-stimulating hormone was noted in 50- and 70-day-old hemicastrated rats compared to normal rats, while levels of luteinizing hormone were basically the same. The increase in Leydig cell volume, interstitial tissue volume, vascular component volume, and plasma testosterone level caused by hemicastration at 40 days of age differed from that at 20 and 30 days of age.

Aging↗