Existence of two adsorbed states for K on the Si(100)(2 x 1) surface: A thermal desorption study.
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Journal Article↗
Biomedical subjects
N Takagi
Publications and source records attributed to N Takagi.
Leachability of denture-base acrylic resins in artificial saliva.
We studied the influence of salivary acidity on leachability of denture-base acrylic resins with etiological interest in denture stomatitis because denture surfaces are frequently exposed to acidic conditions in the oral cavities. Auto-, heat-, and microwave-polymerized resins were immersed in artificial saliva with pH ranging from 4.0 to 6.8 at 37 degrees C, and leachables were pursued quantitatively with time. Methyl methacrylate, methacrylic acid, and benzoic acid leached from all resins. Their concentrations in the saliva were markedly high for auto-polymerized resins, while leachability of heat- and microwave-polymerized resins was so low that quantitative analysis of leachables was impossible. Lower pH showed higher concentrations of methyl methacrylate, although no apparent association was confirmed between salivary acidity and its own leachability. The concentrations of methacrylic acid increased remarkably with an increase in pH, which was probably due to hydrolysis of methyl methacrylate. These results suggest that chemotoxic actions of auto-polymerized resins are potentially ascribable to methyl methacrylate under more acidic conditions and to methacrylic acid under less acidic conditions.
Acrylic Resins↗
High-performance liquid chromatographic analysis of alpha-keto acids produced from amino acid metabolism in oral Bacteroides.
Profiles of metabolic alpha-keto acids were determined by a high-performance liquid chromatographic method and applied to characterization of oral black-pigmented Bacteroides. Each bacterial strain was incubated with amino acids in a chemically defined medium. After production alpha-keto acids were purified by hydrazide gel column treatment and converted to u.v.-absorbing derivatives. They were analysed by reversed-phase ion-pair chromatography. Black-pigmented Bacteroides species were differentiated into two groups according to production of aromatic alpha-keto acids. Bacteroides gingivalis, B. endodontalis and B. loescheii produced both p-hydroxyphenylpyruvic and phenylpyruvic acids. However, no such alpha-keto acids were produced by B. levii, B. intermedius and B. denticola. In addition, production profiles of several aliphatic alpha-keto acids (alpha-ketoglutaric, pyruvic, alpha-ketobutyric, alpha-ketoisovaleric, alpha-ketoisocaproic, and alpha-keto-beta-methylvaleric acids) separated each individual species in such groups. The present study offers useful chemotaxonomic information on amino acid metabolic activity of oral black-pigmented Bacteroides species.
Amino Acids↗
A novel mammalian protein kinase gene (mak) is highly expressed in testicular germ cells at and after meiosis.
We isolated a novel gene designated mak (male germ cell-associated kinase) by using weak cross-hybridization with a tyrosine kinase gene (v-ros). Sequence analysis of the cDNA corresponding to the 2.6-kilobase transcript revealed that the predicted product of rat mak consisted of 622 amino acids and contained protein kinase consensus motifs in its amino-terminal region. Comparison of the deduced amino acid sequence of mak in the kinase domain with those of other protein kinase genes demonstrated that mak was approximately 40% identical to the cdc2-CDC28 gene family in Schizosaccharomyces pombe, Saccharomyces cerevisiae, and humans but less identical to most other protein kinase gene products. Expression of mak was highly tissue specific, and its transcripts were detected almost exclusively in testicular cells entering and after meiosis but hardly detectable in ovarian cells including oocytes, after the dictyotene stage. These results suggest that the mak gene plays an important role in spermatogenesis.
Amino Acid Sequence↗
Detrimental effects of two active X chromosomes on early mouse development.
Matings between female mice carrying Searle's translocation, T(X;16)16H, and normal males give rise to chromosomally unbalanced zygotes with two complete sets of autosomes, one normal X chromosome and one X16 translocation chromosome (XnX16 embryos). Since X chromosome inactivation does not occur in these embryos, probably due to the lack of the inactivation center on X16, XnX16 embryos are functionally disomic for the proximal 63% of the X chromosome and trisomic for the distal segment of chromosome 16. Developmental abnormalities found in XnX16 embryos include: (1) growth retardation detected as early as stage 9, (2) continual loss of embryonic ectoderm cells either by death or by expulsion into the proamniotic cavity, (3) underdevelopment of the ectoplacental cone throughout the course of development, (4) very limited, if any, mesoderm formation, (5) failure in early organogenesis including the embryo, amnion, chorion and yolk sac. Death occurred at 10 days p.c. Since the combination of XO and trisomy 16 does not severely affect early mouse development, it is likely that regulatory mechanisms essential for early embryogenesis do not function correctly in XnX16 embryos due to activity of the extra X chromosome segment of X16.
Animals↗
An extra maternally derived X chromosome is deleterious to early mouse development.
An extra copy of the X chromosome, unlike autosomes, exerts only minor effects on development in mammals including man and mice, because all X chromosomes except one are genetically inactivated. Contrary to this contention, we found that an additional maternally derived X (XM) chromosome, but probably not a paternally derived one (XP), consistently contributes to early death of 41,XXY and 41,XXX embryos in mice. Because of imprinted resistance to inactivation, two doses of XM remain active in the trophectoderm, and seem to be responsible for the failure in the development of the ectoplacental cone and extraembryonic ectoderm, and hence, from early embryonic death. Discordant observations in man indicating viability of XMXMXP and XMXMY individuals suggest that imprinting on the human X chromosome is either weak, unstable or erased before the initiation of X-inactivation in progenitors of extraembryonic membranes.
Animals↗
[Possible mechanisms of the anti-inflammatory action of polyamines].
Carrageenin paw edema of rats was inhibited in a dose-dependent manner by subcutaneous administration of polyamines. The latter had to be administered at least 2 hr before carrageenin challenge to achieve such inhibition. Moreover, inhibition was blocked by the simultaneous injection of actinomycin D. Polyamines also inhibited local bluing reactions to histamine in rats and similarly had to be administered 3 hr previously to achieve inhibition. Polyamines were shown to be glucocorticoid-type anti-inflammatory drugs, and may be glucocorticoids mediators of the synthesis of the postulated vascular permeability inhibitory protein that do not inhibit phospholipase A2 activity. Neutrophil chemotaxis was inhibited by polyamines in a concentration-dependent manner. In contrast to the experience with carrageenin paw edema, simultaneous addition to actinomycin D did not block the inhibitory action of polyamines on neutrophil chemotaxis. These results suggest that polyamines possess at least 2 different anti-inflammatory mechanisms. The first is mediated by the synthesis of an anti-inflammatory protein, and the second consist of direct action on leukocytes.
Animals↗
[A case of mixed connective tissue disease complicated with malignant hypertension].
This case was a 51-year-old woman, who had been diagnosed as having rheumatoid arthritis at some clinic and had been treated with both non-steroidal anti-inflammatory drugs and steroid 3 years before visiting our clinic. When she noticed a decrease in visual acuity and general fatigue in June 1985, she was referred to an ophthalmologist of our hospital, and found to have blood pressure of 240/150 mmHg and KW grade IV retinal findings. She was admitted in our department to examine and treat malignant hypertension. On admission, remarkable hypergammaglobulinemia (29.3%), arthralgia, arthral deformity and pericardial effusion were present thus, she was suspected to be suffering from malignant rheumatoid arthritis. Anti-nuclear antibody (64X), anti-nuclear ribonucleoprotein antibody (64X) and anti-RNase sensitive antibody of anti-extractable nuclear antigens (ENA) antibody (81920X) were positive, while anti-RNase resistant antibody of anti-ENA antibody was negative. Immunologically, her condition was consistent with mixed connective tissue disease (MCTD). Since urinary protein was positive and creatinine clearance was 46.0 ml/min, renal function was thought to be diminished. Her chest roentgenogram revealed cardiomegaly (CTR 67.5%) and an increase in pulmonary vascular shadow. An echocardiogram demonstrated the presence of pericardial effusion. Plasma renin activity was 3.3 ng/ml/h and it was suspected that an intrarenal ischemic change resulted in increased renin release from the juxta-glomerular apparatus, leading to the marked hypertension. Treatment was started with prednisolone 60 mg/day during 4 weeks.(ABSTRACT TRUNCATED AT 250 WORDS)
Captopril↗
High performance liquid chromatographic analysis of time-dependent changes in urinary excretion of indoleamines following tryptophan administration.
Analytical conditions of prepurification extraction and HPLC separation were optimized for determination of urinary serotonin and tryptamine. Under optimal conditions, serotonin, tryptamine and an internal standard were extracted with 15% v/v n-propanol in diethyl ether from urine samples alkalized with a phosphate buffer (0.75 mol/L, pH 10.0), and then they were re-extracted into an HCl solution (0.1 mol/L). Purified indoleamines were simultaneously separated by reversed-phase ion-pair HPLC with native fluorescence detection. Urinary serotonin and tryptamine were selectively determined within about 45 min per sample for the whole procedure. Analytical recovery, reproducibility and detection sensitivity were satisfactory for pursuing time-dependent changes in indoleamine levels. Urinary excretion profiles of serotonin and tryptamine in subjects dosed with L-tryptophan were successfully analyzed by our method.
Adult↗
Interdigitating cell sarcoma (ICS). Evidence of interdigitating cell origin, immunocytochemical studies with monoclonal anti-ICS antibodies.
Three independent mouse monoclonal antibodies (mAbs) ID1 (IgG3), ID2 and ID3 (IgM) were raised against whole cells of a surgically resected human interdigitating cell sarcoma (ICS). In immunoperoxidase staining, these mAbs strongly stained the cytoplasm of ICS neoplastic cells as well as interdigitating cells in normal lymphoid tissues. These mAbs also detected monocyte/macrophages and dendritic cells, although their staining was highly variable depending on tissue distribution of the cells. Additional immuno-histological and enzyme histochemical study revealed that the neoplastic cells of ICS had cytoplasmic acid phosphatase and membranous alkaline phosphatase activity, and also possessed S100 beta protein, Ki-1 antigen. DAKO-macrophage antigen, and weak vimentin activity. Neither rearrangement of immunoglobulin heavy chain gene nor of T-cell receptor genes was detected in the DNA of ICS by Southern hybridization. These observations provide further confirmation of our previous finding (Nakamura et al. 1988, 1989) that the origin of ICS is interdigitating rather than lymphoid cell, and indicate that our mAbs could be useful as a cellular differentiation marker of interdigitating cells and for diagnosis of ICS.
Animals↗
Effects of Tween 80 and sodium fluoride on extracellular glucosyltransferase production and membrane lipids of Streptococcus mutans.
1. Both Tween 80 and sodium fluoride significantly enhanced total extracellular glucosyltransferase activities of Streptococcus mutans. 2. Water-insoluble and water-soluble glucan formation were uniformly increased by Tween 80, whereas fluoride stimulated only water-soluble glucan formation. 3. Elevated glucan formation was due to an increase in enzymes secreted from bacterial cells. 4. Fatty acid composition and phospholipid content in bacterial membrane were changed by Tween 80, although sodium fluoride scarcely showed these changes. 5. Comparative results suggest that modulation of membrane lipids participates in mutansucrase production but not in dextransucrase production of S. mutans.
Glucosyltransferases↗
High-performance liquid chromatographic estimation of eluates from denture base polymers.
A quantitative analytical method using high-performance liquid chromatography is developed to estimate elution profiles of dental acrylic polymers used for denture bases. The method is applied to elution studies in distilled water of resins polymerized by different representative methods. Elution properties or 'leachabilities' vary depending on polymerization conditions. Methyl methacrylate, methacrylic acid and benzoic acid are eluted from autopolymerized resins at the highest eluate concentrations and are followed by heat- and microwave-polymerized resins. These results appear to be comparable to residual amounts of the eluates in resins and their cytotoxic potencies reported.
Acrylic Resins↗
The platysma myocutaneous flap for oral reconstruction. Experience with MacFee's cervical incision.
The present study was performed to demonstrate and evaluate the effectiveness of the Platysma Myocutaneous Flap in conjunction with MacFee's cervical incision (MacFee, 1960) for reconstruction after oral cancer excision. Ten squamous cell carcinoma cases were provided for postoperative evaluation of tongue movement and aesthetic problems of the cervical skin. It was found that the thickness of the skin island was adequate for covering the oral defects and was not a hindrance to proper postoperative function. MacFee's incision improved the condition of the scar caused by flap elevation. The procedure for preparing the muscle pedicle beneath the cervical skin tunnel was carried out without much difficulty by carefully preparing the surgical field.
Adult↗
Human atrial natriuretic peptide in aortic and coronary sinus blood during atrial pacing in patients with ischemic heart disease.
This study investigated the plasma concentrations of human atrial natriuretic peptide (hANP) of blood samples obtained from the aorta and coronary sinus (CS) in 19 male patients (mean age of 52.8 +/- 2.1 years) with ischemic heart disease before and during atrial pacing. The plasma concentrations of hANP were measured by radioimmunoassay, and the secretion rate of hANP was calculated on the basis of the CS-aorta difference in plasma hANP concentration and the CS flow rate recorded at blood sampling. Before atrial pacing, aortic plasma hANP concentration showed a significant positive correlation with mean pulmonary capillary wedge pressure (r = 0.67, p less than 0.002) or mean pulmonary artery pressure (r = 0.71, p less than 0.001), and a significant negative correlation with left ventricular ejection fraction (r = -0.50, p less than 0.05). During atrial pacing, aortic plasma hANP concentration increased from 67 +/- 13 (SEM) to 151 +/- 33 pg/ml (p less than 0.01), CS plasma hANP concentration from 727 +/- 121 to 1205 +/- 228 pg/ml (p less than 0.01), and the hANP secretion rate from 45.4 +/- 14.8 to 86.8 +/- 28.2 ng/min (p less than 0.05, n = 12). The aortic plasma hANP concentration was significantly correlated with the CS plasma hANP concentration (r = 0.81, p less than 0.001) or the hANP secretion rate (r = 0.70, p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)
Atrial Natriuretic Factor↗
bcl-2 gene rearrangement analysis in Japanese B cell lymphoma; novel bcl-2 recombination with immunoglobulin kappa chain gene.
The rearrangement of bcl-2 gene was studied in 56 Japanese B cell lymphoma cases to investigate the contribution of bcl-2 gene to lymphomagenesis in Japan. Ten out of 56 cases showed bcl-2 gene rearrangement; it was detected in only 5 out of 16 follicular lymphoma cases (31%) and in 5 out of 40 diffuse B cell lymphoma cases (13%). The incidence of bcl-2 gene involvement in Japanese follicular lymphomas was lower than those reported in the United States. This might contribute to the lower incidence of follicular lymphoma cases in Japan. Novel recombination between bcl-2 and Ig kappa genes at the 5' region of bcl-2 and J kappa 4 segment was observed in one follicular lymphoma case, suggesting that bcl-2 gene is transcriptionally activated by Ig kappa enhancer. It was also suggested that this case had originated from a more differentiated B cell than most follicular lymphomas with bcl-2-Ig H recombination.
B-Lymphocytes↗
Changes of the serum amikacin (AMK) level in patients with serious acute renal failure treated by continuous arteriovenous hemofiltration (CAVH).
This study clarified changes in the serum amikacin (AMK) levels in the blood of 5 patients (4 men and 1 woman; average age 59.2 +/- 5.9 years) with serious acute renal failure treated by continuous arteriovenous hemofiltration (CAVH). The following principal results were obtained. (A) The average remaining rate of AMK in the blood after 6 h was 60.8 +/- 5.3% and 50.4 +/- 5.3% after 12 h. The average half-life period (t1/2 beta) of AMK in the blood during CAVH was 18.3 +/- 3.4 h. (B) The remaining rate of AMK in the blood after 12 h correlated significantly with the blood urea nitrogen (BUN) level (r = 0.71, p less than 0.05) and with the volume of urine excreted per day (r = -0.71, p less than 0.05). (C) The average lowest AMK concentration after 24 h for a continuous 17-day period was 3.3 micrograms/ml. These results suggest that the administration of 100 mg of AMK once a day is useful and safe for patients with serious acute renal failure treated by CAVH and that it will not accumulate in the body.
Acute Kidney Injury↗
[Comparison of five modes of dialysis in neurosurgical patients with renal failure].
In neurosurgical patients with renal failure, dialysis entails specific problems, chief of which is increased intracranial pressure and progressive brain edema as a result of rapid lowering of the serum osmolality. Another major problem is a tendency to hemorrhage, in response to either systemic heparinization or insufficient dialysis. The authors describe the results obtained with hemodialysis (HD), continuous arteriovenous hemofiltration (CAVH), continuous ambulatory peritoneal dialysis (CAPD), continuous peritoneal dialysis (CPD), and intermittent peritoneal dialysis (IPD). Nine patients were treated with HD, one with CAVH, five with CAPD or CPD, and two with IPD. Three of the six patients treated with continuous dialysis (CAVH, CAPD, and CPD) died, whereas intermittent dialysis (HD and IPD) carried an 82% mortality rate (nine of 11 patients). The causes of death were progressive brain edema in three cases, intracranial hemorrhage in three, gastrointestinal bleeding in three, overhydration due to insufficient dialysis in one, septicemia in one, and rupture of a cerebral aneurysm in one. Continuous dialysis appeared to be superior to intermittent dialysis in these neurosurgical patients in that it produced less brain edema and was less often associated with hemorrhage due to insufficient dialysis. In HD and CAVH, systemic heparinization was also thought to account for the high incidence of hemorrhage. However, CAVH with short half-life anticoagulants may be useful in patients who have abdominal complications and are therefore not suitable candidates for peritoneal dialysis.
Adult↗
[A case of left ventricular pseudoaneurysm with severe cardiac failure and premature ventricular beats].
A surgically successful case of left ventricular pseudoaneurysm 10 years after an acute myocardial infarction was reported. A 63-year-old man had an acute inferior myocardial infarction 10 years ago. Recently congestive heart failure and premature ventricular beats developed. He was diagnosed as a left ventricular pseudoaneurysm by echocardiogram, CT scan, and left ventriculogram. After the operation, the symptoms diminished and improvement of left ventricular function was observed. A brief review of the literature is given.
Cardiac Complexes, Premature↗