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Biomedical subjects

E Furuya

Publications and source records attributed to E Furuya.

At least 73 records · Page 4Linked to original sources
PubMed1980

An activation factor of liver phosphofructokinase.

Pure phosphofructokinase (ATP:D-fructose-6-phosphate 1-phosphotransferase, EC 2.7.1.11) from liver is strongly inhibited by ATP, whereas crude phosphofructokinase is only slightly inhibited by ATP. A factor that is removed from the enzyme during purification and can prevent the inhibition of phosphofructokinase by ATP has been isolated. The factor can be resolved into three components that differ in molecular weights, as shown by gel filtration on Sephadex G-25. These factors overcome the ATP inhibition but have no effect on the catalytic activity under the optimum assay conditions. Furthermore, AMP acts syngeristically with the activation factor in reversing ATP inhibition. It is proposed that the activation of phosphofructokinase by the activation factor and AMP is sufficient to account for the glycolytic flux in the liver.

Adenosine Triphosphate↗
PubMed1980

A direct colorimetric method for the determination of phospholipids with dithiocyanatoiron reagent.

A simple and sensitive colorimetric method for the quantitative determination of phospholipids in various kinds of biological materials is described. The method, modification of a previous method using tetrathiocyanatocobaltate, is based on the formation of hydrophobic complexes between dithiocyanatoiron reagent and phospholipids. Under the standard conditions all species of neutral phospholipids, including lysophosphatidylcholine and sphingomyelin, form stable hydrophobic complexes with the iron compound. Although species of acidic phospholipids also have slight affinity for the iron compound, they do not disturb the assay appreciably, because their contents in biological materials are low. Under special conditions, the iron compound reacts only with phosphatidylcholine, and therefore it may also be used for specific determination of this phospholipid.

Colorimetry↗
PubMed1980

Therapeutic effects of tracheostomy in two cases of hypersomnia with respiratory disturbance during sleep.

Recently the association of hypersomnia and respiratory insufficiency without lesion in the respiratory organ has attracted attention of many investigators. Obese patients with such a condition have been called the Pickwickian syndrome. In this report, two non-obese patients with a similar condition were presented, one with micrognathia and frequent apneic episodes during sleep, and the other with laryngeal stenosis due to paralysis of the bilateral laryngeal nerves and chronic laryngitis. Tracheostomy had a prompt and long-lasting therapeutic effect to make their sleep stable and also to relieve their excessive daytime sleepiness. These findings suggest that the obstruction or stenosis of the upper airway during sleep disturbed their nocturnal sleep, and that their excessive daytime sleepiness was a phenomenon compensating for their disturbed nocturnal sleep.

Adult↗
PubMed1979

A simple method for measuring phosphatidylcholine as its hydrophobic complex with tetrathiocyanatocobaltate.

A sensitive colorimetric method for quantitative determination of phosphatidylcholine is described. The procedure is very simple, not involving lipid extraction or acid digestion, and can be used for direct estimation of phosphatidylcholine in blood plasma. The method depends on the formation of a stable hydrophobic complex of phosphatidylcholine with tetrathiocyanatocobaltate. Similar complexes are formed by other species of diacylglycerophosphoryl esters, but the absorbance coefficients of these complexes are only 10 to 20% of that of the phosphatidylcholine complex. Phospholipids without unsaturated fatty acids, such as dipalmitoyl phosphatidylcholine, do not form hydrophobic complexes. Lysophosphatidylcholine and sphingolipids also do not form similar complexes.

Animals↗
PubMed1979

Interaction of mitochondrial aspartate aminotransferase with negatively charged lecithin liposomes.

Several kinds of hydrophilic proteins were examined to determine their interaction with artificial liposomes. Mitochondrial aspartate aminotransferase (m-GOT) [EC 2.6.1.1], as well as cytochrome c, was found to interact strongly with negatively charged liposomes. In each case, an appreciable amount of the protein bound to liposomes remained unreleased after raising the salt concentration in the medium. The m-GOT tightly bound to the liposomes was also found to become latent in its enzymatic activity, and could be reversibly activated by solubilization of the liposomes with detergent. This is also the case for cytochrome c, which ceases to be reducible by external reductant, such as dithionite. Furthermore, the tightly bound m-GOT was not susceptible to the proteolytic action of trypsin, or that of Nagarse. From these observations it can be inferred that these basic proteins interact with acidic liposomes not only electrostatically but also hydrophobically. This kind of hydrophobic interaction was not observed in the combination of positively charged liposomes and acidic proteins, including s-GOT. Mitochondrial GOT was shown to be bound to isolated intact mitochondrial, but the bound enzyme was fully active, in contrast to the case of acidic liposomes. The hydrophobic interaction of water-soluble protein with liposomes is discussed in connection with the penetration of matrix enzyme through mitochondrial membranes.

Aspartate Aminotransferases↗
PubMed1979

Removal of contaminating substances before gas-liquid-chromatographic determination of aldosterone in urine.

This paper deals with removal of contaminants before gas-chromatographic determination of aldosterone in urine. Urine is incubated with beta-glucuronidase, which hydrolyzes all beta-glucuronides except aldosterone-18-glucuronide. The contaminants (the aglycones released and other methylene chloride-soluble substances) are extracted with methylene chloride. Solvolysis of the aqueous phase liberates aldosterone from aldosterone-18-glucuronide, which then is extracted with methylene chloride and oxidized by use of periodic acid. The resulting lactone can be easily separated by one-dimensional thin-layer chromatography and determined by gas-liquid chromatography.

Aldosterone↗
PubMed1977

Hydrolysis of steroid glucuronides with beta-glucuronidase preparations from bovine liver, Helix pomatia, and E. coli.

We determined the enzymic activity of beta-glucuronidase preparations from bovine liver, Helix pomatia, and Escherischia coli with steroid glucuronides and nonsteroid glucuronides as substrates. We also studied the effect of Na2SO4 on the enzymic hydrolysis of several substrates with the three preparations of beta-glucuronidase. Na2SO4 increases the rate of hydrolysis of all substrates with beta-glucuronidase from bovine liver. Hydrolysis of a steroid glucoronide with beta-glucuronidase from Helix pomatia and E. coli is inhibited by Na2SO4. None of the three enzyme preparations gives complete hydrolysis of urinary steroid conjugates, because urine contains inhibitors, which can be removed by absorption chromatography of the urine on a column of neutral polystyrene resin Amberlite XAD-2. But when Amberlite XAD-2 is not used, hydrolysis of urinary glucuronides of androsterone, etiocholanolone, pregnanediol, estriol, and 17-hydroxycorticosteroids proves that, given an incubation time of 24 h, the beta-glucuronidase preparation from bovine liver, in the presence of Na2SO4, is suited for determining all of the above steroids except esriol; the preparation from Helix pomatia is good for determining estriol and 17-hydroxycorticosteroids; the preparation from E. coli is good for determining androsterone, 17-hydroxycorticosteroids, and especially estriol, the glucuronide, of which is maximally hydrolyzed in 2 h.

17-Hydroxycorticosteroids↗
PubMed1977

Effect of sodium sulfate on the hydrolysis of 17-hydroxycorticosteroid- and p-nitrophenyl-glucuronides with beta-glucuronidase preparations from bovine liver.

Previous papers dealt with the discovery that hydrolysis of 17-hydroxycorticosteroid glucuronides in urine with beta-glucuronidase preparations from bovine liver is increased by adding sodium sulfate to the incubation medium. Here, we conclude that sodium sulfate not only increases the activity of bovine liver beta-glucuronidase on 17-hydroxycorticosteroid glucuronides and p-nitrophenyl glucuronides, but also removes the inhibitory activity of substances of high molecular weight in urine and, moreover, inhibits urine putrefaction during the hydrolysis. The net effect is an increased yield of urinary 17-hydroxycorticosteroids. In the incubation with sodium sulfate (Na2SO4, final concentration 80 g/liter, 500 Fishman units of beta-glucuronidase per milliliter of urine, pH 5.0, 48 degrees C, 18 h) the analytical recovery of 17-hydroxycorticosteroid glucuronides added to 12 urine samples proved to be 98 +/- 1.8% (95-100).

17-Hydroxycorticosteroids↗
PubMed1977

Removal of interference by erythromycin, phenazopyridine, and methenamine mandelate in the Porter-Silber reaction.

Erythromycin, phenazopyridine, methenamine mandelate, acetazolamide, and ascorbic acid reportedly interfere with the Porter-Silber reaction in the determination of urinary 17-hydroxycorticosteroids. Sodium bisulfite, added to the urine after hydrolysis with glucuronidase, removed almost all nonsteroidal interferences in urine from healthy adults medicated with the first three drugs, but such studies proved that acetazolamide and ascorbic acid do not interfere with the Porter--Silber reaction, whether or not sodium bisulfite is added.

17-Hydroxycorticosteroids↗
PubMed1976

Sleep satiation in narcoleptic patients.

UNLABELLED: Polygraphic sleep recording was performed in 20 narcoleptics with one or more of the auxiliary symptoms, 4 narcoleptics with only sleep attacks and 10 normals during one night and into the following day. Total sleep time in the narcoleptics did not differ significantly from that in the normals. Sleep of the narcoleptics with auxiliary symptoms was unstable with frequent awakening. The temporal organization of the REM--NREM sleep cycle was irregular in the narcoleptics with auxiliary symptoms, compared with those in the other two groups. Percentage of Stage 1 was significantly larger in the narcoleptics with auxiliary symptoms than in the other two groups and percentage of Stage 2 was smaller. Percentage of Stage 4 was smaller in the narcoleptics with auxiliary symptoms than in those with only sleep attacks. Percentages of Stages 3 and REM did not differentiate the three groups. Spindle density during Stage 2 did not differentiate the three groups. Sleep onset Stage REM was frequently observed exclusively in the narcoleptics with auxiliary symptoms. Excluding the instances showing sleep onset Stage REM, mean latency of initial episodes of REM sleep in the three groups was shorter after daytime sleep onset than after nighttime sleep onset. In the narcoleptics with auxiliary symptoms, no significant correlation was found between the percentage of Stage REM and clinical findings. CONCLUSIONS: the sleep attacks in narcoleptics are due to an ill-timed, strong tendency to fall asleep (including both REM and NREM sleep), and it is therefore suggested that they are manifestations of their disturbed circadian rhythm of sleep--wakefulness cycle.

Adolescent↗
PubMed1975

The effect of sodium bisulfite on the removal of drugs and their metabolites interfering with the Porter-Silber reaction in the determination of urinary 17-hydroxycorticosteroids.

In the determination of urinary 17-hydroxycorticosteroids, the urine is saturated with NaHSO3 after hydrolysis with beta-glucuronidase and then extracted with methylene chloride. Sodium bisfulfite removes almost all non-steroidal impurities in the urines from patients medicated with acetylspiramycin, leucomycin, erythromycin, triacetylolenadomycin, rifampicin and tranquilizers such as chlorpromazine, which interfere with the absorption at 410 nm. in the subsquent Porter-Silber reaction. In order to increase the specificity of a routine method, a procedure conducted by Allen has been often employed: The sum of 370- and 450-nm. absorbances is subtracted from twice absorbance at 410 nm. However, the procedure could not be used in the medicated urines mentioned above, because the spectral absorption curve of these drugs and their metabolites in the Porter-Silber reaction was not a straight but a strongly convex or concave line in the 370-450-nm. range. Using the present method, interference with the Porter-Silber reaction was not found in the urines from patients medicated with chloramphenicol, minocycline, chlordiazepoxide, meprobamate, methyprylon, nitrazepam, synthetic penicillins such as hetacillin, oxacillin and cloxacillin, or cephalosporins such as cephalexin and cephalothin. However, to obtain correct values in urines from patients medicated with spironolactone, it was necessary to subject the urines to treatment with methylene chloride before enzyme hydrolysis.

17-Hydroxycorticosteroids↗
PubMed1975

Development of mitochondrial membranes in anaerobically grown yeast cells.

Biochemical analyses of mitochondrial marker substances, especially cardiolipin and oligomycin-sensitive ATPase [EC 3.6.1.3], as well as electron microscopic observations were carried out to eludicate the process of mitochondrial development in annaerobic yeast cells. Cardiolipin was found to be localized in the mitochondria in anaerobic cells. Its cellular content was a little higher in the stationary phase than in the exponential phase in glucose-grown cells and increased further in galactose-grown cells. The lipid content of the mitochondrial preparation obtained from glucose-grown stationary cells was nearly as high as that from galactose-grown cells. It was also comparable to that of aerobic cells in the stationary phase, where mitochondria are fully developed. Both cellular and mitochondrial levels of oligomycin-sensitive ATPase activity were also found to rise markedly in galactose-grown anaerobic cells, although not in stationary phase cells grown anaerobically on glucose. These high levels of the mitochondrial markers indicate a developmental change in mitochondrial structure even in anaerobically grown cells, which lack mitochondrial cytochromes. In the process of aerobic adaptation, respiratory system formation was observed to occur much faster in galactose-grown cells than in glucose-grown cells, and not to be inhibited by chloramphenicol and high concentrations of glucose structure in anaerobic cells. The developmental change was also corroborated by electron microscopic observations, which revealed the occurrence of two types of mitochondria in anaerobic cells. One was found in glucose-repressed cells and was characterized by the presence of numerous electron-dense granules in the matrix. In contrast, the other type, found in glucose-derepressed cells, had an electron-lucent matrix. No crista membrane was seen in either type of mitochondria in anaerobic cells, although the infoldings of the inner membrane, which partition the matrix into two parts and therefore are called "septum membranes," appeared frequently in the stationary phase cells. On the basis of these results, the process of mitochondrial development in yeast cells is discussed.

Adenosine Triphosphatases↗
PubMed1975

[Decomposition of steroids during incubation with beta-glucuronidase and during storage of urine].

Androsterone, etiocholanolone, pregnanetriol, dehydroepiandrosterone, pregnanediol, tetrahydrocortisol, 5-pregnenolone and 11-beta-OH-androsterone were incubated with beta-glucuronidase preparations (Helix pomatia, bovine liver and E. coli) for 96 hrs at 37 degrees C. After extraction and silylation they were gas-chromatographed. The first 3 steroids were left practically intact. The least decomposition of the last 5 steroids occurred with the liver enzyme. Testosterone and 11-ketoandrosterone without the enzymes showed 74 and 35% recoveries. Cortisol and tetrahydrocortisol, incubated with the first two enzymes for 18 hrs at 37 degrees and 48 degrees C, showed nearly 100% recoveries. The recoveries of 17-OHCS in urines (pH 7.8-8.8), stored for 7 days, was 80% at 20 degrees-25 degrees C and 55% at 25 degrees-30 degrees C. The same samples, brought to pH 1.8-2.8 WITH NaHSO4 before the storage, showed a 100% recovery.

17-Hydroxycorticosteroids↗