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Biomedical subjects

K Otsuka

Publications and source records attributed to K Otsuka.

At least 217 records · Page 12Linked to original sources
PubMed1993

Impaired insulin sensitivity in young, lean normotensive offspring of essential hypertensives: possible role of disturbed calcium metabolism.

OBJECTIVES: To determine whether insulin sensitivity is impaired in normotensive offspring of essential hypertensives and to investigate how it relates to disturbed calcium metabolism. DESIGN: In 10 young lean, normotensive subjects with family histories of essential hypertension and in 10 age-matched controls we investigated insulin sensitivity by the euglycaemic hyperinsulinaemic clamp technique, and 75-g oral glucose tolerance test (GTT). We simultaneously measured calcium-related factors, including the intracellular calcium concentration in platelets. RESULTS: Insulin-induced glucose uptake was significantly impaired in subjects with positive compared with in subjects with negative family history of essential hypertension. Intracellular calcium concentration was significantly higher in subjects with positive than in those with negative family history. Insulin sensitivity was inversely correlated with intracellular calcium concentration (r = -0.56; P < 0.05). Those who showed a higher intracellular calcium concentration had impaired insulin sensitivity. Oral GTT results were normal in both groups. CONCLUSION: Impaired insulin sensitivity and disturbed calcium metabolism exist before the onset of hypertension. Insulin sensitivity correlates inversely with intracellular calcium concentration. These findings suggest that the association of the impaired insulin sensitivity and disturbed calcium metabolism may contribute to the development of hypertension.

Adult↗
PubMed1993

Effects of alpha,beta-blocker, arotinolol chloride, on 24-h blood pressure--difference between elderly and younger hypertensive patients.

To assess the effect of age on the circadian blood pressure (BP) after an alpha,beta-adrenergic blocker, the ambulatory BP was measured before and after arotinolol chloride administration in nine younger (mean age 49.1 years) and 14 older (72.1 years) patients with essential hypertension. After a 4-week control period, arotinolol chloride was administered twice daily (08:00 and 20:00 hours) for 8 weeks and the ambulatory BP was measured non-invasively at the end of the control and treatment period. Arotinolol significantly reduced the daytime systolic BP from 152.3 to 140.9 mmHg (P < 0.05) and night-time systolic BP from 137.3 to 122.3 mmHg (P < 0.01) in the younger hypertensive patients. In contrast, in the older group, the night-time systolic BP did not show a significant change, although the daytime systolic BP was significantly reduced from 155.0 to 142.2 mmHg (P < 0.02). Diastolic BP in both groups was significantly reduced by arotinolol during the day and night. Night-time reduction of BP was significantly less in the older group (-8.6 vs -15.1 mmHg for the systolic pressure P < 0.01; -5.8 vs -9.8 mmHg for the diastolic pressure P < 0.01).

Adrenergic beta-Antagonists↗
PubMed1993

Effect of humidity on solid-state isomerization of various kinds of lactose during grinding.

The effect of humidity on isomerization during grinding of alpha-monohydrate, alpha-anhydrate and beta-anhydrate of lactose was investigated. Samples were ground in an agate centrifugal ball mill at 270 rev min-1 at room temperature (21 degrees C) and at 5 and 60% relative humidity. Crystallinity of the ground lactose was measured by Hermans' method from the powder X-ray diffraction profiles. The alpha- and beta-lactose content of the ground lactose was measured by using angular rotation spectrophotometry. The crystalline lactose samples were transformed into noncrystalline solids by mechanical stress during grinding. After grinding, the adsorbed water content of all ground lactose samples increased, and the isomerized amount increased with increase of the water content during grinding at 5 and 60% relative humidity. The results suggest that the isomerization rate of alpha-monohydrate during grinding may depend on the crystallinity, but those of alpha- and beta-anhydrate depend on the content of adsorbed water.

Crystallization↗
PubMed1993

Genetics and obstructive sleep apnea syndrome: a study of human leukocyte antigen (HLA) typing.

To investigate the possible influence of genetics in subjects with obstructive sleep apnea syndrome (OSAS), HLA-A, B, C, and DR antigens were studied in 32 Japanese subjects with OSAS. The frequency of HLA-A2 antigen was markedly increased in the patients with OSAS compared with normal controls (81.3% vs 40.6%) and compared with the Japanese population (40.7%), Pc < 0.035 and Pc < 0.007, respectively. HLA-B39 was found more frequently in OSAS patients than in the Japanese population (Pc < 0.018), but not in the controls. No significant deviation was observed in the frequencies of HLA-C and DR antigens between the OSAS patients and the controls. We conclude that genetics is important in the development of OSAS.

Adult↗
PubMed1993

Collagenase and collagenase inhibitors secreted by cultured human periodontal ligament cells.

We have developed a new assay method for collagenase activity, in the presence of two different types of collagenase inhibitors, in culture medium of periodontal ligament (PDL) cells. Human PDL cells were cultured with serum-free alpha-MEM for 5 days after reaching confluency, and the culture medium was then harvested. Collagenase and collagenase inhibitors in the medium were concentrated by ammonium sulfate precipitation. The precipitate was dissolved, and the suspension was applied to an Ultrogel AcA 54 column for partial purification. Collagenase inhibitor activity was detected as two peaks; a small inhibitor molecule of about 32 kDa sensitive only to dithiothreitol (DTT), and a large one of about 70 kDa considerably more sensitive to 4-aminophenylmercuric acetate (APMA) than to DTT. Therefore, pretreatment of the sample preparation with both DTT and APMA was necessary in order to inactivate the inhibitors prior to assay of latent collagenase. This observation indicates that PDL cells secrete collagenase and two collagenase inhibitors without any stimulation in vitro.

Cells, Cultured↗
PubMed1993

Characteristics of a 28-kDa collagenous protein extracted with guanidine from EDTA-demineralized rabbit alveolar bone.

Bone proteins in alveolar bone of mandibles from young adult rabbits (3-month-old) were extracted with 4.0 M guanidine hydrochloride (GuHCl), followed by 0.5 M ethylenediaminetetraacetate, and again with 4.0 M GuHCl (G2-ext). The proteins in the G2-ext were fractionated on a gel-filtration column, followed by an anion-exchange column in the presence of 7.0 M urea. A 28-kDa protein was isolated from the G2-ext. The purified 28-kDa protein showed intense staining with silver on SDS-PAGE slab-gel under reducing conditions. This protein was digested with bacterial collagenase, and a 19-kDa fragment appeared on the gel. However, the protein was not susceptible to reduction with cyanogen bromide. The protein did not bind to hydroxyapatite crystals in the presence of 7.0 M urea, and also did not bind to some lectins. On SDS-PAGE under non-reducing conditions, the protein migrated as two bands; a new band appeared at approximately the 85-kDa region in addition to the original 28-kDa band. The amino acid compositions of the protein were similar to those of the alpha 1-pN-propeptide of type I procollagen obtained from other tissues.

Alveolar Process↗
PubMed1993

Gingival epithelial cells secrete a substance which increases the collagenolytic enzyme activity of periodontal ligament cells.

To examine whether the gingival epithelium provokes a loss of connective tissue attachment during periodontitis, periodontal ligament (PDL) cells and gingival fibroblasts (GF) were cultured with conditioned medium of gingival epithelial cells, and the collagenolytic activity of PDL cells and GF were examined, respectively. The epithelial cells were cultured in the presence or absence of lipopolysaccharide (LPS), and the respective conditioned media were added to the cultures of PDL cells and GF. The collagenolytic response of PDL cells to both of the conditioned media was 3- to 10-fold higher than that of each control, whereas the response of GF was only 1.4-fold higher. The LPS-stimulated epithelial conditioned medium showed a stimulation rate for collagenolytic activity similar to that of the LPS-free conditioned medium. These results suggest that human gingival epithelial cells, without LPS stimulation, secrete a substance which accelerates the collagenolytic enzyme activity of PDL cells for degradation of PDL fibers, in the absence of GF enzyme activity.

Cell Division↗
PubMed1993

[Age and gender difference in circadian rhythm in blood pressure].

In order to evaluate the effect of gender and aging on the diurnal rhythm of blood pressure (BP), we performed ambulatory BP monitoring in 267 normotensive volunteers (mean age +/- SD 52.1 +/- 24.6 years, range 16-93 years, 114 men, 153 women). Ambulatory 24-hour BP was recorded every 30 minutes with an oscillometric method by ABPM630 (Nippon-Kolin, Japan). Circadian rhythm was determined by fitting the 24-hour cosine function curve. Subjects were divided into three age groups, consisting of the Y group (age < 30), M group (age > or = 30 but < 60), and E group (age > or = 60). Highest normal values of the 24-hour mean BP (90 percentile of the values) were 126/75 mmHg in the Y group, 126/76 mmHg in the M group, and 154/85 mmHg in the E group in men. They were 117/67 mmHg, 125/77 mmHg 151/79 mmHg respectively in women. The MESOR of SBP increased with age in women, though it was significantly higher only in the E group among men. The amplitude of SBP decreased with age significantly only in men. The acrophase of SBP shifted to an earlier time of day with aging in both men and women. The trends in the circadian rhythm of DBP with age were similar to those of SBP. In conclusion, the circadian rhythm of blood pressure varies with gender and aging. The 24-hour blood pressure values should be considered with evaluating sex-age matched reference values.

Adult↗
PubMed1993

Chronobiology in cardiology.

In these years, circadian periodicity in the onset of myocardial ischemia, myocardial infarction, sudden cardiac death and ischemic stroke has been confirmed by several investigators. There has also been reported that there exists a significant circadian rhythm in ventricular arrhythmias in patients with myocardial infarction. These recent advances in chronocardiology depend on a development of a high quality built-in A/D converter in ambulatory ECG monitoring system and a remarkably developed sophisticated software. One of the most current topics in recent years is heart rate (HR) variability. As an index of HR variability, RR50 is frequently estimated by the cosine fitting technique. Next, we analyzed the so-called Lorenz plot for another index of HR variability, that is preceding R-R intervals and coupling intervals were plotted sequentially every 3 hours on the abscissa and ordinate, respectively. Finally, we investigated HR variability by power spectral analysis of R-R intervals both by the maximum entropy method and the fast Fourier transform. Mainly, in this paper, we introduced current topics in HR variability, but recent advances in ambulatory blood pressure (BP) monitoring system are also strikingly remarkable. Our newly developed monitoring system of physical activity donated quite a few informations evaluating episodic changes of HR and BP. This device was also useful for finding out the difference between the individual life styles, such as the eveningness versus morningness. In conclusion, these very recent advances in ambulatory monitoring system should be really available for the clinical practice from this time onward.

Adult↗
PubMed1993

[Improvement of biventricular heart failure in a case of obstructive sleep apnea syndrome by nasal CPAP therapy].

A 42-year-old male patient with obstructive sleep apnea syndrome (OSAS) suffering from biventricular heart failure is reported. He had been treated for OSAS with conventional therapy. However, he complained of severe dyspnea in association with extreme weight gain and general edema. Therefore, he was admitted to our department. He weighed 168 kg on admission, and marked edema was observed. Chest film revealed significant dilatation of the cardiac silhouette and pleural effusion. PaO2 was 37 mmHg and PaCO2 was 66 mmHg. Polysomnography showed an apnea index of 58.3 and severe oxygen desaturation during sleep. Right heart catheterization showed elevation of mean pulmonary artery pressure mPAP: 55 mmHg) and pulmonary capillary wedge pressure (Pcwp: 33 mmHg) suggesting biventricular heart failure. Digitalization and diuretic therapy were immediately initiated. In addition, nasal CPAP was applied to this patient during sleep, and sleep apnea and oxygen desaturation were almost completely reversed. Significant diuresis was observed, and blood gas data and sleep disturbance were improved. Fifty-nine days after admission, his weight had decreased to 96 kg, and mPAP and Pcwp decreased to 32 and 23 mmHg, respectively. This case demonstrates that nasal CPA is an effective tool for the treatment severe OSAS patients.

Adult↗
PubMed1992

Effect of geometric factors on hydration kinetics of theophylline anhydrate tablets.

The effect of tablet thickness on the hydration kinetics of types I and II theophylline anhydrate tablets at 95% relative humidity and 35 degrees C was studied with various kinetic equations. Samples of 1- and 2-cm-diameter tablets (1 g) were compressed at 1000 kg/cm2. Types I and II tablets expanded by 11-17% in volume during hydration to the monohydrate. The thickness expansion of all tablets exceeded the diameter expansion. After the hygroscopicity test, the final expansion ratio of type I tablets was more than that of type II tablets. The hydration kinetics analysis suggested that the hydration of theophylline anhydrate tablets proceeds as follows: Hydration of the 1-cm-diameter type I tablet followed the two-dimensional phase boundary equation, and that of the 1-cm-diameter type II tablet followed the three-dimensional phase boundary equation, but those of the 2-cm-diameter types I and II tablets followed the equation for two-dimensional growth of nuclei. The hydration kinetics of tablets does not depend on the nature of bulk powder but on geometrical factors (tablet thickness and porosity).

Chemical Phenomena↗