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Biomedical subjects

S Yamaguchi

Publications and source records attributed to S Yamaguchi.

At least 811 records · Page 45Linked to original sources

Age-dependent induction of preneoplastic liver cell foci by 2-acetylaminofluorene, phenobarbital and acetaminophen in F344 rats initially treated with diethylnitrosamine.

Effects of age on the induction of glutathione S-transferase placental form (GST-P)-positive hepatic foci in rats were examined using a medium-term liver bioassay system (for carcinogens). F344 male rats aged 6, 26 and 46 weeks were initially given a single intraperitoneal injection of diethylnitrosamine (DEN, 200 mg/kg) and, beginning 2 weeks later, received 0.02% 2-acetylaminofluorene (2-AAF), 0.05% phenobarbital (PB) or 1.3% acetaminophen (AAP) in the diet for 6 weeks. All animals were subjected to two-thirds hepatectomy 3 weeks after the DEN injection and were killed at week 8. Quantitative analysis of GST-P-positive foci revealed significantly (P less than 0.001) increased induction over control levels in terms of both numbers and areas for 2-AAF at all ages (6, 26 and 46 weeks), but especially in the 6-week-old case. In the PB- and AAP-treated groups, the respective enhancing and inhibitory influences were most pronounced in the animals aged 6 weeks, and were less marked in older rats. Thus, the response of F344 rats to the modifying effects of chemicals was age-dependent, the conclusion being drawn that young rats are more susceptible and therefore more appropriate for assessment of carcinogenic, promoting and inhibitory effects of chemicals.

2-Acetylaminofluorene↗

Modifying effects of various chemicals on preneoplastic and neoplastic lesion development in a wide-spectrum organ carcinogenesis model using F344 rats.

Modifying potentials of various chemicals on tumor development were investigated in a wide-spectrum organ carcinogenesis model using male F344/DuCrj rats. The animals were treated with N-nitrosodiethylamine (100 mg/kg body weight, ip, single injection at the commencement of the study), N-methyl-N-nitrosourea (20 mg/kg body weight, ip, 4 times during weeks 1 and 2) and N-bis(2-hydroxypropyl)nitrosamine (0.1% in drinking water, during weeks 3 and 4) for multi-organ initiation and then were given one of 14 test chemicals including 6 hepatocarcinogens, 7 non-hepatocarcinogens and 1 non-carcinogen, or basal diet for 16 weeks. All rats were killed at the end of week 20, and the major organs were carefully examined for preneoplastic and neoplastic lesions. Immunohistochemical demonstration of glutathione S-transferase-positive foci was also used for quantitative assessment of liver preneoplastic lesion development. Modifying effects were shown for 11 out of 14 test agents in the liver, forestomach, glandular stomach, lung, urinary bladder or thyroid, 7 of them targeting more than two organs. This was the first demonstration to our knowledge that clofibrate possesses enhancing potential for urinary bladder carcinogenesis and an inhibiting effect on thyroid carcinogenesis. Caprolactam showed no effect in any organ, in agreement with its established inactivity. The results indicated that the system could be reliably applied as a medium-term multiple organ bioassay for assessment of the modification potential of test agents in unknown target sites.

Administration, Oral↗

Sex differences in o-phenylphenol and sodium o-phenylphenate rat urinary bladder carcinogenesis: urinary metabolites and electrolytes under conditions of aciduria and alkalinuria.

F344 male and female rats were administered 1.25% o-phenylphenol (OPP) or 2% sodium o-phenylphenate (Na-OPP) in combination with 3% NaHCO3 or 1% NH4Cl for 8 weeks and changes in the urinary bladder histopathology and the urinary components were examined. Administration of OPP with NaHCO3 resulted in marked urothelial hyperplasia in the urinary bladder of male rats, the response being less pronounced in females. OPP alone exerted no proliferative effect and NaHCO3 induced only slight hyperplasia in males. Na-OPP alone induced mild hyperplastic lesions only in males, this being completely prevented by concomitant administration of NH4Cl. The findings thus demonstrated a clear correlation between hyperplastic response and reported carcinogenic potential of these treatments. Of the urinary factors examined, increases in levels of pH and sodium ion concentration were positively associated with proliferative lesions especially in males, although the findings failed to explain the sex difference. Urinary concentrations of non-conjugated forms of OPP metabolites were also not directly correlated with the development of hyperplasias. Thus, changes in individual urinary factors presumably affect urothelial proliferation in combination rather than separately. The presence of OPP metabolites, including 2-phenyl-1,4-benzoquinone, in the urine may be unimportant in the OPP urinary carcinogenesis even under conditions of alkalinuria and high sodium ion concentration.

Ammonium Chloride↗

Newly identified forms of electron transfer flavoprotein deficiency in two patients with glutaric aciduria type II.

Newly identified forms of electron transfer flavoprotein (ETF) deficiency in two patients with glutaric aciduria type II (GA II) were described. GA II has been attributed to a defect of either ETF or ETF dehydrogenase, resulting in multiple acyl-CoA dehydrogenation deficiency. ETF is a mitochondrial flavoprotein consisting of an alpha-subunit, alpha-ETF, and a beta-subunit, beta-ETF. We used pulse-chase experiments to examine the biosynthesis of ETF in fibroblasts from two patients with GA II. Patient 1 was a boy with the neonatal onset form, but without congenital anomalies, who is living at age 2 y. A defect of beta-ETF biosynthesis was noted in this patient. Patient 2 was a boy with the neonatal onset form with congenital anomalies who died on the 3rd postnatal day. He presented with a peculiar face and polycystic kidneys. In patient 2, both alpha- and beta-ETF were synthesized, but both the subunits were rapidly degraded. The lability of ETF was considered to be the cause of GA II in this patient. These two cases appear to be new forms of ETF deficiency in GA II.

Child, Preschool↗

Prenatal diagnosis and neonatal monitoring of a fetus with glutaric aciduria type II due to electron transfer flavoprotein (beta-subunit) deficiency.

The prenatal diagnosis of a male fetus with glutaric aciduria type II and the time course of metabolite urinary excretion, starting immediately after birth, are described. Prenatal diagnosis was undertaken at the 17th wk of gestation by immunoblot analysis and pulse labeling experiments of amniocytes and, retrospectively, by stable isotope dilution analysis of six metabolites in amniotic fluid. The results were as follows: 1) The immunochemical analysis on cultured amniocytes showed that the fetus, as the previous index case in this family, was affected with a deficiency of the beta-subunit of electron transfer flavoprotein. 2) Glutarate concentration was significantly increased in the cell-free supernatant of the amniotic fluid. In the postnatal period, most of the organic acids and acylglycines characteristic of the disorder appeared in urine within a week, although an increased excretion of hexanoylglycine was the only biochemical abnormality detectable in the first urine sample collected at 9 h after birth. Growth and development of this infant were normal during the following 6 mo of life, when he was receiving oral supplementation with L-carnitine and riboflavin. It should be underscored that transient abnormalities in routine blood tests (glutamic oxaloacetic transaminase, lactate dehydrogenase, and creatine phosphokinase) were present soon after birth, despite his asymptomatic clinical course. Early detection and aggressive treatment could be effective in such a form of glutaric aciduria type II.

Amniotic Fluid↗

The response of left ventricular regional function to afterload stress in patients with old myocardial infarction and ventricular aneurysm.

The functional response of the left ventricle with scar to increased afterload, was examined in 15 patients with old myocardial infarction and left ventricular aneurysm (OMI). Interventional cine left ventriculography during elevating left ventricular pressure with methoxamine. Wall motion was assessed by the radial and the centerline method. Augmented afterload didn't change ejection fraction in patients with OMI, but normalized wall motion (Z) increased in the aneurysmal region and decreased in the remote region in both methods. In the remote region in patients with OMI, afterload stress shortened left ventricular pressure-radial length (P-L) loops along length axis, and reduced percent systolic radial shortening (SS). In the aneurysmal region, P-L loops showed systolic elongation of length at rest and the slope of end-diastolic point to end-systolic point became steeper with increased afterload, resulting in a decrease of aneurysmal expansion. In summary, with increasing afterload, wall motion decreased in non-infarcted regions and increased in aneurysmal regions, in left ventricles with aneurysm. This mechanism may be interpreted as afterload-induced shifts of P-L loops in each region.

Adult↗

Significant stenosis of coronary arteries in patients with single and multiple vessel diseases without previous myocardial infarction.

To determine what degree of stenosis should be counted as a significant lesion in each of 3 major coronary arteries in classification of the number of vessels involved, coronary arteriographic percent diameter narrowing (by quantitative angiography) was compared with thallium-201 scinitgraphic redistribution on treadmill exercise in 47 patients with evidence of exercise myocardial ischemia and greater than or equal to 50% diameter narrowing (visual assessment) in at least 1 major coronary artery. Severity of exercise-induced myocardial ischemia for the entire left ventricle (assessed by averaged redistribution index) was separated most sufficiently with definition of 63-64% or greater between patient groups with no- and single-, single- and double-, and double- and triple-vessel diseases. Collaterals and intraventricular contractile interaction are possibly the factors making definition more severe in extensive coronary artery disease. Since the visual method gives an overestimation of stenosis, it was concluded that vessel diameter narrowing of 70% or more should be regarded as significant in patients with single and multiple vessel diseases if the visual method is used.

Adult↗

Cerebral blood flow patterns at major vessel bifurcations and aneurysms in rats.

Cerebral arterial bifurcations in rats were treated to induce cerebral aneurysms experimentally, and flow patterns of latex particles introduced under a constant flow rate were analyzed with a 16-mm cine-camera and videocassette recorder. Cerebral aneurysms were produced by ligating one common carotid artery, inducing experimental hypertension, and feeding the animals beta-aminopropionitrile. After perfusion and fixation, samples of cerebral arterial bifurcations with shallow invaginations and with small aneurysms were obtained and used for analysis. Bifurcations in rats without experimental treatment were used as control specimens. Flow studies in the control bifurcations showed that the apical intimal pad, not the apex itself, acted as the flow divider. Small particles tended to accumulate at the region just distal to the apical intimal pad, where the initial aneurysmal changes are known to occur. This indicates stagnation of flow at that site. In the bifurcations with shallow invaginations and small aneurysms, a marked pressure gradient was present at the proximal end of the aneurysm orifice. A tendency for stagnation of small particles near the aneurysm wall was also observed. The wall shear stress was highest at the distal end of the aneurysmal orifice, which may be responsible for the development of these lesions.

Animals↗

[Ultrasonographic study on kidneys in patients with acute renal failure].

Ultrasonotomograms of 22 kidneys were obtained in 11 patients with renal-acute renal failure (renal-ARF). The underlying diseases of renal-ARF were acute tubular necrosis in 8 patients and acute on-set chronic glomerulonephritis in 3 patients. They were treated by hemodialysis in 10 patients and intermittent peritoneal dialysis in 1 patient. Ultrasonic measurement of the size of kidneys revealed that the thickness (anterior-posterior diameter) and the ratio of thickness to length (T/L) were greater in patients with ARF than in those with chronic renal failure and normal renal function. The patients with a low value of T/L (under 0.60) had a significantly greater urine volume than those with high a value of T/L (0.60 or more). The sonographic features of renal-ARF kidneys were marked increase in parenchymal echogenicity and appearance of hypoechoic swollen renal pyramids with sharpness of the corticomedullary border. In the course of ARF, these sonographic changes gradually disappeared when the patients had recovered from ARF. However, the prognosis was poor in patients with severer sonographic findings. We believe that repeated ultrasonic examination of the kidneys in patients with renal-ARF is useful for not only differential diagnosis of post-renal urinary obstruction but evaluating the course of ARF.

Acute Kidney Injury↗

Purification and characterization of a novel lyase from Cellulomonas sp. that degrades Fusarium and Gibberella acidic polysaccharides.

A Cellulomonas sp. isolated from soil produced a novel lyase that degraded the acidic polysaccharide of Fusarium sp. M7-1 with the formation of mannose and O-beta-D-mannopyranosyl-(1----2)-D-mannose. DEAE-Toyopearl 650M column chromatography showed three lyase activity peaks (fractions I, II, and III). The major fraction was purified to homogeneity by polyacrylamide gel electrophoresis analysis, and its molecular weight was 74,000. The optimum pH was 6.5 to 8.0 and the stable pH range was 6.0 to 8.0. The purified enzyme did not degrade glucuronic or galacturonic acid-containing polysaccharides such as chondroitin, hyaluronic acid, pectin, or pectic acid. However, the purified enzyme specifically degraded various Fusarium and Gibberella acidic polysaccharides, and unsaturated sugars were produced with the release of mannose and O-beta-D-mannopyranosyl-(1----2)-D-mannose. These results suggest that the acidic polysaccharides derived from Fusarium and Gibberella have similar structures.

Bacterial Proteins↗

Mucopolysaccharidosis type VII: characterization of mutations and molecular heterogeneity.

We identified two different exonic point mutations causing beta-glucuronidase (beta G1) deficiency in two Japanese patients with mucopolysaccharidosis type VII (MPSVII). Enzyme assay of lysates of the lymphocytes and cultured fibroblasts showed little residual activity. The beta G1-specific mRNA levels were normal, as determined by northern blot analysis. Mutated cDNA clones, including the entire coding sequence, were isolated using the polymerase chain reaction (PCR) products derived from beta G1-deficient fibroblasts. Sequence analysis of the full-length mutated cDNAs showed C----T transitions, which resulted in a single Ala619----Val change (case 1, a 24-year-old male) and a Arg382----Cys change (case 2, a 7-year-old female). The former change was revealed by a loss of the cleavage site for the Fnu4HI in the mutated cDNA. On the basis of the loss of Fnu4HI restriction site, the patient (case 1) was a homozygote with this mutation. The mutational change in patient 2 was confirmed by direct sequencing and by demonstrating heterozygosity for the mutation in her parents. The Ala619----Val and Arg382----Cys mutations each disrupt a different domain which is highly conserved among human, rat, and Escherichia coli beta G1s. Each of these two amino acid changes reduced the beta G1 activity of the corresponding mutant beta G1 expressed following transfection of COS cells with expression vectors harboring the mutated cDNAs.

Adult↗

[Effect of natural panting frequency and cheek support on the plethysmographic determination of thoracic gas volume in patients with chronic obstructive pulmonary disease].

The authors studied the effects of natural panting frequency (NF) and the cheek support on the plethysmographic measurement of thoracic gas volume (TGV) in 8 normal subjects (non-smokers) and 46 patients with chronic obstructive pulmonary disease (COPD). The patients were divided into 2 groups according to the degree of airway obstruction (group I; specific airway conductance (SGaw) greater than 0.1 (n = 18), group II; SGaw less than 0.1 (n = 28)). TGV was measured with a pressure-type body plethysmograph (BP). NF was 2.00 +/- 0.43 Hz (mean +/- SD) in control subjects, 1.92 +/- 0.78 Hz in group I, and 1.39 +/- 0.59 Hz in group II, respectively, indicating lower NF in the patients with severe airway obstruction. In control subjects and group I, the differences between TGV at NF and at 0.5-1.0 Hz (TGVNF-TGV1.0) were -0.01 +/- 0.07L, and -0.06 +/- 0.16L, respectively, and cheek support did not alter the difference. On the other hand, in group II, the difference was slightly larger than other groups in spite of the lower NF, and this overestimation was abolished by cheek support (0.13 +/- 0.25L-----0.06 +/- 0.27L, p less than 0.05). These results suggest that, in patients with severe airway obstruction, TGVNF may be overestimated even if NF is relatively low. This overestimation may be mainly due to the extrathoracic airway compliance including the cheek.

Adult↗

[The effect of kanpou medicine on the growth and aggregation of calcium oxalate crystals in vitro].

The effects of the compositional drugs of kanpou medicine on the growth and aggregation of calcium oxalate crystals were investigated in vitro. In the seeded crystal system, the inhibitory activities were calculated from the change of the number (Ia), total volume (Ig) and fractional volume (I) of crystals determined by a Coulter Multisizer. Among the tested drugs (Takusha, Akyou, Chorei, Bukuryou, Kasseki, Kinsensou, Kagosou), only Takusha and Kagosou had strong inhibitory activities on the growth and aggregation at the concentration of 5 micrograms/ml and 10 micrograms/ml (Ia greater than 80%, Ig, I greater than 90%). No significant correlation was observed between inhibitory activities and alcian blue precipitable polyanions (ABPP) of each drug. Thus some naturally existing substances composing the kanpou medicine may help prevent the stone formation in clinical use.

Calcium Oxalate↗

[Primary hyperparathyroidism: problems on surgical indication and procedure].

Between 1959 and Oct. 1990, 307 cases of primary hyperparathyroidism (PHPT) were operated on in our hospital. Among them, 23 cases (7.5%) were asymptomatic chemical type of PHPT, and the incidence of this type has been increasing these days. Various symptoms or signs including urolithiasis, bone disease, cardiovascular disease, gastrointestinal disease, diabetes mellitus and others were associated with PHPT. Especially, as a lethal factor, malignant tumors developed in 14 cases (4.6%); 9 cases of non-medullary thyroid cancer and tumors of other organs. In consideration of these associated disorders, the chemical type of PHPT should be operated prophylactically. In order to reduce operative complications, unilateral exploration is available for the cases of single normally localized adenoma; 85.7% of our 307 cases. Moreover, the positive rate of preoperative localized test by CT and ultrasonography for such adenomas is 78% in the recent 5 years. The predictive values of successful operation by unilateral exploration are 89% in the cases of normally localized single adenoma and 76% in all PHPT.

Humans↗

Transglycosylation activity of endo-beta-N-acetylglucosaminidase from Arthrobacter protophormiae.

Endo-beta-N-acetylglucosaminidase from Arthrobacter protophormiae has transglycosylation activity. Treatment of (Man)6(GlcNAc)2Asn with the enzyme in the presence of free N-acetylglucosamine gave a mixture of (Man)6GlcNAc and (Man)6GlcNAc beta 1----4GlcNAc mixture. N-Acetylglucosamine at the reducing end of the latter sugar chain was found by HPLC of the carbohydrate composition and of an exoglycosidase digest of the pyridylamino derivative of the reducing-end residue, and by 400 MHz 1H-NMR spectroscopy.

Acetylglucosamine↗

[Effect of aging on P300 in normal subjects].

The P300 component of the event-related brain potential (ERP) is generated when subjects discriminate stimulus events which differ from one another. There are many reports about the effect of age on P300 in clinically normal subjects. However, these subjects may include individuals with silent cerebral infarctions or abnormal periventricular hyperintensity (PVH) on MRI. In this study, we completely excluded such subjects using MRI and examined the effect of aging on P300. One hundred four neurologically normal subjects (mean age 58.6 years, 55 men, 49 women) who had no lesions or severe PVH on MRI were selected. An oddball stimulus paradigm was employed and ERPs were elicited by presenting a series of binaural 1000 (82%) and 2000Hz (18%) tones through headphones. Prolongation of P300 latency was significantly correlated with advancing age (p less than 0.001): P300 latency increased by approximately 1.7 msec per year of age, with a prominent increase after age 60. But there was no significant difference between males and females in P300 latency. The significant correlation between age and P300 amplitude was observed only at Pz (p less than 0.05). These results indicate that there is a gradual mental decline with aging in normal subjects without silent cerebral infarctions or PVH.

Adult↗

[Hemodynamics in the cerebral cortex and basal ganglia--observation on normal volunteers and patients with lacunes using PET].

We examined ten healthy volunteers using positron emission tomography (PET) in order to elucidate regional changes and correlations in the cerebral circulation and oxygen metabolism. We also studied eight lacunar stroke patients so as to disclose the influences of vascular risk factors and aging on the cerebral blood flow and metabolism. We can conclude from our result as follows: 1. Cerebral blood volume (CBV) was minimum in the basal ganglia and cerebral blood flow (CBF)/CBV ratio was higher than that of cerebral cortex in healthy volunteers; 2. CBF of gray matter in healthy volunteers correlated with CBV and cerebral metabolic rate of oxygen where oxygen extraction fraction inversely correlated with CBF, CBV, and CBF/CBV; and 3. the basal ganglia CBF/CBV ratio in lacunar stroke patients was lower than that of healthy volunteers. These findings suggested that the perfusion pressure in the basal ganglia was so high in the normal condition that the angionecrosis or occlusion in the perforating arteries would be induced, especially in the aged and hypertensive patients.

Adult↗