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Biomedical subjects

N Yamada

Publications and source records attributed to N Yamada.

At least 649 records · Page 36Linked to original sources
PubMed1990

Digital subtraction of radiograph in evaluating alveolar bone changes after initial periodontal therapy.

The purpose of this study was to determine the effect of initial periodontal therapy on crestal bone remineralization with the use of a digital subtraction method for quantitative analysis. Fifteen crestal sites randomly selected from five patients were examined at the initial visit, after completion of oral hygiene instruction, and 1, 3, and 6 months after scaling and root planing with standardized radiographs. The radiographs were digitized by means of a drum-scanning microdensitometer with a sampling aperture of 50 microns producing 256 gray levels and corrected for difference of contrast between image pairs. Results were as follows: (1) statistically significant changes were observed even 1 month after the therapy and (2) the extent of changes was quantitatively expressed and monotonically increased with time. These results indicate that subtraction radiography may be a reproducible and quantitative method for the evaluation of periodontal therapy.

Alveolar Process↗
PubMed1990

Circadian rhythms in depression. Part I: Monitoring of the circadian body temperature rhythm.

In order to develop a sampling strategy and a method for analyzing the circadian body temperature pattern, we monitored estimates of the temperature in four ways using rectal, oral, axillary and deep body temperature from the skin surface every hour for 72 consecutive hours in 10 normal control subjects. Data obtained were analyzed with the least-squares method to estimate the circadian rhythm. Deep body temperature from the skin surface correlated better with rectal temperature than with either oral or axillary temperature in all subjects. The correlation coefficient between rectal and deep body temperature from the skin surface ranged between 0.66 and 0.89. The acrophases calculated from the deep body temperature from the skin surface every 2 h for 48 h were consistent with those based on the rectal temperature every 10 min for 72 h. We believe that monitoring of the deep body temperature from the skin surface, in this manner, at intervals of 2 h for a period of 2 days, is a promising method for investigating circadian body temperature rhythm, because it causes less discomfort than other measures and has greater statistical validity for data computation.

Adult↗
PubMed1990

Circadian rhythms in depression. Part II: Circadian rhythms in inpatients with various mental disorders.

We investigated longitudinally the circadian body temperature rhythms in 65 inpatients with various mental disorders, 38 of whom had major depressive episodes, by estimating the deep body temperature from the skin surface every 2 h for a consecutive 48-h period. To estimate the circadian rhythm, the data obtained were analyzed by the least-squares method and maximum entropy spectral analysis (MEM). Circadian rhythm disturbances in patients with depression were likely to be manifested in phase variability rather than in phase advance. The amplitude of body temperature of the depressed group was significantly less than that of the control group. A positive correlation between the mesor and the severity of the depressive symptoms was found. Moreover, the body temperature of the patients with affective disorders, both in the depressive and in the manic state, tended to fluctuate so much as not only to fit poorly to sinusoid curves, but also to reduce the periodicity of the circadian rhythm. On the basis of these findings, we conclude that the essential feature of the rhythm disturbances in affective disorders is not the phase shift but the instability of the circadian temperature rhythm.

Adult↗
PubMed1990

Activities of free oxygen radical scavenger enzymes in human liver.

Activities of superoxide dismutase, catalase and glutathione peroxidase were measured in liver biopsy specimens from patients with various liver diseases, including six with chronic persistent hepatitis, nine with chronic active hepatitis, nine with non-alcoholic cirrhosis, eight with alcoholic cirrhosis and eight with acute hepatitis. Measurements from ten patients without liver disease were used as controls. Levels of total superoxide dismutase activity in the chronic active hepatitis and non-alcoholic cirrhosis groups were significantly lower than those in the controls (p less than 0.01 and p less than 0.01, respectively). The level of total superoxide dismutase activity in the acute hepatitis group was significantly higher than that in the control group (p less than 0.01). The levels of Cu,Zn-superoxide dismutase activity in all the experimental groups, except for the chronic persistent hepatitis group, were significantly lower than those in the controls (p less than 0.01 in all groups). The levels of Mn-superoxide dismutase activity in the alcoholic cirrhosis and acute hepatitis groups were significantly higher than those in the controls (p less than 0.01 and p less than 0.01, respectively), although no difference in the level of this enzyme was seen among the controls, chronic persistent hepatitis, chronic active hepatitis and non-alcoholic cirrhosis groups. The levels of catalase activity in the groups with chronic active hepatitis, non-alcoholic and alcoholic cirrhosis and acute hepatitis were significantly lower than those in the controls (p less than 0.01 in all groups). Glutathione peroxidase activity showed no difference among the groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Relationship between free-running period and motor activity in blinded rats.

The free-running rhythms of motor activity in blinded rats were measured by two different devices, an Automex or a running wheel. The period of free-running rhythm measured by a running wheel was likely to be shorter than that measured by an Automex, indicating that subtle environmental difference, such as whether a cage is equipped with a wheel or not, can affect the free-running period. In addition, we found a negative correlation not only between the free-running period measured by a running wheel and that measured by an Automex, but between the free-running period and the number of wheel revolutions per day. This is the first evidence that motor activity, other than the external factors such as light intensity and temperature, may be related to change in the free-running period.

Animals↗
PubMed1990

Cholesterol-free diet with a high ratio of polyunsaturated to saturated fatty acids in heterozygous familial hypercholesterolemia: significant lowering effect on plasma cholesterol.

We have studied the effect of diet therapy on plasma lipoprotein metabolism in heterozygous familial hypercholesterolemia. Seven patients with a mean plasma cholesterol concentration of 323 +/- 67 mg/dl were hospitalized and kept on a cholesterol-free diet for as long as 11 days without any medication. The content of dietary cholesterol was approximately 1.4 mg a day, and dietary fat, carbohydrate and protein comprised 18.0, 69.2 and 12.8% of calories, respectively. The ratio of polyunsaturated to saturated fatty acids (P/S) was 3.1. At the end of the study period, plasma cholesterol was lowered by 14.2%, from 323 to 277 mg/dl, and low density lipoprotein (LDL) cholesterol by 17.5% from 229 to 189 mg/dl. Using density gradient ultracentrifugation, the major change in LDL cholesterol was found to be in those fractions with a mean density between 1.034 and 1.042, where cholesterol concentrations decreased from 132 to 87 mg/dl (34%). These results indicate that diet therapy with free-cholesterol and a high ratio of P/S is highly effective in controlling plasma cholesterol levels in heterozygous familial hypercholesterolemia.

Adult↗
PubMed1990

Comparative morphological and biological studies on the itraconazole- and ketoconazole-resistant mutants of Cryptococcus neoformans.

Studies were carried out on the resistance in vitro of Cryptococcus neoformans to the oral antifungal drugs itraconazole and ketoconazole. None of the six sensitive strains tested developed resistance to itraconazole or ketoconazole by serial transfer on Sabouraud's glucose agar plates containing increasing concentrations of either drug. One mutant resistant to itraconazole, and one mutant resistant to ketoconazole, were isolated from the progenies of yeast cells surviving after treatment with a mutagenic substance, N-methyl-N'-nitro-N-nitroso-guanidine. These mutants were capable of growing in the presence of high concentrations of the drugs to which they were resistant. The itraconazole- and ketoconazole-resistant mutants obtained by mutagenesis were compared morphologically and biologically. The itraconazole-resistant mutant was characterized by the formation of very rough colonies which varied in size and shape, production of a large number of cell clusters, complete loss of capsule formation, and major degenerative changes in the cells, while in the ketoconazole-resistant mutant these changes were less pronounced and no cell clusters were formed. The acquisition of resistance was more stable in the itraconazole-resistant mutant than in the ketoconazole-resistant mutant. Both mutants showed partial cross-resistance and complete loss of virulence for mice.

Animals↗
PubMed1990

Nucleotide sequence of rice dwarf virus genome segment 4.

The complete nucleotide sequence of rice dwarf virus (RDV) genome segment 4 was determined. Genome segment 4 was 2468 nucleotides long and had a long open reading frame initiating at nucleotides 64 to 66 and terminating at 2245 to 2247. The deduced polypeptide contained 727 amino acid residues with an Mr of 79.8K. Amino acid sequences similar to a 'zinc-finger' and purine NTP-binding motifs were present in the deduced polypeptide. Considerable amino acid sequence homology was detected between genome segment 4 of RDV and wound tumor virus (WTV). One of the sequences similar to the 'zinc-finger' motif was present in a conserved region of the polypeptide of both viruses. However, the sequence similar to the purine NTP-binding motif was not present in the polypeptide encoded by genome segment 4 of WTV.

Amino Acid Sequence↗
PubMed1990

The temporomandibular joint in rheumatoid arthritis--a comparative clinical and tomographic study pre- and post-prosthesis.

Six partially or fully edentulous rheumatoid patients participated in the study. By comparing the clinical symptoms and tomograms of the temporomandibular joints (TMJS) pre-prosthesis with those post-prosthesis, this report assesses whether dental treatment could provide positive help for TMJS in patients with rheumatoid arthritis (RA). Among the clinical symptoms of TMJ dysfunction, pain from the TMJ region and limitations of movement were improved in all the patients post-prosthesis. Tomographic evidence of desirable remodelling of the condylar heads was observed in two cases.

Adult↗
PubMed1990

Plasma cholesterol-lowering activity of monocyte colony-stimulating factor (M-CSF).

We investigated the action of monocyte colony-stimulating factor (M-CSF) on plasma cholesterol metabolism. Recombinant human monocyte colony-stimulating factor (rhM-CSF) was intravenously injected into Watanabe heritable hyperlipidemic (WHHL) rabbits that were deficient in LDL receptor. The treated rabbits showed decreases in plasma total cholesterol levels from 493 +/- 39 to 416 +/- 45 mg/dl (about 15%) during the treatment. The decrease in total plasma cholesterol level was due to decreased levels of lipoproteins containing apo B 100 such as VLDL, IDL, and LDL. The effect of M-CSF on the LDL-receptor-deficient animal in vivo and evidence from Northern blot analysis of liver suggested that M-CSF lowers plasma cholesterol level through activated uptake of lipoproteins containing apo B 100 via pathways other than the hepatic LDL receptor. We have started a clinical study to evaluate the plasma cholesterol-lowering effect of M-CSF in patients with familial hypercholesterolemia, and have observed a decreased in total plasma cholesterol level in one of three patients treated with M-CSF. M-CSF may provide new insight into plasma cholesterol metabolism and a possible new tool to treat patients with hypercholesterolemia and atherosclerosis.

Animals↗
PubMed1990

Evaluation of the susceptibility effect on the phase images of a simple gradient echo.

The phase shifts of a simple gradient echo (fast low-angle shot) were correlated with the local change in resonance frequency due to the differences in susceptibility among tissues (susceptibility effect). Susceptibility effects were considered theoretically, and the phase shifts for spherical and cylindrical configurations were calculated. A 1.5-T magnetic resonance unit and phantoms filled with solutions of copper chloride in water were used to obtain the phase images. The phase shifts of the simple gradient echo coincided with the values calculated with use of the sum of the macroscopic magnetic field and the cavity field of Lorentz. The authors conclude that the gap of the phase shifts at interfaces of tissues is useful in the evaluation of differences in magnetic susceptibility among tissues.

Cerebral Hemorrhage↗
PubMed1990

Effect of exogenous apo E on the cellular binding of lipoproteins.

It is well known that apolipoprotein E (apo E) has a significant role in the metabolism of plasma cholesterol through receptor-mediated endocytosis of lipoproteins containing apo B 100. We have reported that intravenous administration of apo E increases the clearance of lipoproteins containing apo B 100, resulting in reduced plasma cholesterol levels in WHHL rabbits. In the present study, we investigated the effects of exogenous apo E on lipoprotein binding to cell surface receptors. Lipoproteins were enriched in apo E by the incubation with purified apo E. Among lipoproteins enriched in apo E, VLDL and intermediate-density lipoprotein demonstrated higher binding affinity to cell surface receptor on fibroblast than respective unmodified lipoproteins. In competitive binding study, VLDL enriched by apo E (VLDL + E) completely suppressed 125I-LDL binding to human skin fibroblasts and showed the greatest binding activity among different lipoprotein classes, whereas both VLDL and LDL incompletely suppressed a binding of 125I-VLDL + E. This result indicated that apo-E-rich VLDL can bind not only to LDL receptor but to binding sites other than LDL receptors.

Animals↗
PubMed1990

Centrally mediated inhibitory effect of 5-[2-(diethylamino)ethyl]amino-5,11-dihydro[1]benzoxepino[3,4- b]pyridine trihydrochloride (KW-5805) on gastric acid secretion in rats.

KW-5805, 5-[2-(diethylamino)ethyl]amino-5,11-dihydro[1]benzoxepino[3,4- b]pyridine trihydrochloride, is a new tricyclic compound with antiulcer activities. Its effect on stimulated gastric acid secretion was investigated in the perfused stomach of anesthetized rats. KW-5805 at 0.3-10 mg/kg, i.v., dose-dependently inhibited gastric acid secretion stimulated by 2-deoxy-D-glucose (2-DG). On the other hand, the compound at 10-20 mg/kg, i.v., exerted a moderate decrease in gastric acid secretion stimulated by bethanechol; and at 10 mg/kg, i.v., it produced no change in gastric acid secretion evoked peripherally by vagal electrical stimulation. When applied intracerebroventricularly at 1-5 micrograms/rat, this compound dose-relatedly reduced gastric acid secretion stimulated by 2-DG. Three main metabolites (KF-10504, KF-9530 and KF-10847) of KW-5805 at 1 mg/kg, i.v., caused no significant decrease in gastric acid secretion stimulated by 2-DG. Doxepin, a tricyclic compound, definitely depressed the 2-DG stimulated gastric acid secretion at 1 mg/kg, i.v. It is suggested that intravenous administration of KW-5805 inhibits gastric acid secretion stimulated by 2-DG, mainly via centrally mediated mechanisms, and that biotransformation of KW-5805 to the metabolites contributes little to the development of the antisecretory effect.

Animals↗
PubMed1990

The release of hepatic triglyceride lipase from rat monolayered hepatocytes in primary culture.

The release of hepatic triglyceride lipase from cultured rat hepatocytes and its hormonal regulation were studied. The activity of lipase released into the medium in the presence of heparin was increasing for 24 hours on the 2nd day of culture. The activity in the absence of heparin was only 10% of that in the presence of heparin. When hepatocytes were cultured with anti-hepatic triglyceride lipase IgG, the lipase activity was suppressed by 92%. The results suggest that the enzyme released into the culture medium is identical to hepatic triglyceride lipase which can be released only in the presence of heparin, the mode of release being similar to that of lipoprotein lipase from adipocytes. The addition of colchicine and monensin to the medium resulted in the inhibition of lipase secretion by 20% and 61%, respectively. Insulin enhanced lipase activity only 20%, whereas dexamethasone suppressed the activity by 44%. These data indicated that hepatic triglyceride lipase is secreted and released from hepatocytes in the presence of heparin and its secretion is regulated by hormones.

Animals↗