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Biomedical subjects

T Miki

Publications and source records attributed to T Miki.

At least 721 records · Page 40Linked to original sources
PubMed1991

Parathyroid hormone secretion in diabetes mellitus.

To investigate the parathyroid function in diabetes mellitus, we performed an oral phosphate load in 6 diabetic patients and 6 nondiabetic subjects without renal failure (serum creatinine less than 1.5 mg/dl). Each subject received a total of 2.0 g of phosphate daily per os on 5 consecutive days. Blood and urine samples were obtained daily before and 2 h after the administration of phosphate in the morning. All subjects responded with a similar increase in the serum phosphorus concentration and fall in the ionized calcium concentration. Intact parathyroid hormone levels rose by 2.6-fold in the control subjects but by less than 1.5-fold in the diabetic subjects. It was concluded that hyporesponsiveness of the parathyroid hormone to phosphate administration was found in the diabetic patients without renal failure.

Aged↗
PubMed1991

Decreased bone mineral density in diabetic patients on hemodialysis.

Renal osteodystrophy in hemodialyzed patients with DM-HD shows different features from that in non-DM,HD. Two studies were done. One was a comparison of BMD in 30 non-DM,HD patients and 30 DM-HD patients. The second was a comparison of possible factors affecting calcium metabolism in the higher and lower BMD groups (n = 20/21) in the DM-HD patients. BMD was measured by dual-energy X-ray absorptiometry (DEXA; Hologic QDR 1,000/W) in the third lumbar vertebra (L3), head, pelvis, and whole body. The BMDs of the DM-HD group were lower in these areas and whole body than that in the non-DM,HD group. A significant difference was found in the head BMD (p less than 0.05). In the second study, factors which may contribute to the differences in BMD were compared in the DM-HD patients divided into higher and lower BMD of the head. The group with higher head BMD had a value 110% of the mean value or more. Clinical and biochemical test results (age, the time since the first dialysis, body weight, the degree of obesity, height, serum calcium, serum phosphate, serum aluminum, serum c-PTH level and the dose of 1 alpha-OH-D3) were compared. The degree of obesity of the patients with higher BMD was significantly larger than that with lower BMD (p less than 0.005).

Aged↗
PubMed1991

3-O-alkylascorbic acids as free radical quenchers. II. Inhibitory effects on some lipid peroxidation models.

We previously found that 3-O-dodecylcarbomethylascorbic acid (3-RASA,3,HX-0112) exhibited a potent inhibitory effect on biochemical lipid peroxidation and that 3-RASA (3) alleviated myocardial lesions induced by ischemia-reperfusion treatment in rats. In this study we examined the mode of action of 3-RASA (3) on the inhibition of lipid peroxidation. There was no reducing activity by 3-RASA (3) (i.e., no oxide was produced) against ferric ions and superoxide anion radicals. The low reducing activity of 3-RASA (3) against a radical as compared to that of alpha-tocopherol was obtained by using a stable radical. However, 3-RASA (3) had a potent inhibitory effect, almost equal to that of alpha-tocopherol, in the model of lipid peroxidation dependent on enzymatic superoxide generation. 3-RASA (3) very strongly inhibited the chain-reaction of the peroxidation induced by Fe(2+)-linoleic acid hydroxyperoxide. On the basis of these findings, it appears that the anti-lipid-peroxidative effects of 3-RASA (3) are due to the inhibition of the radical chain-reaction, as a chain-breaking antioxidant.

Ascorbic Acid↗
PubMed1991

Effect of intermittent oral 1,25(OH)2D3 therapy on bone Gla protein in dialysis patients.

Serum Bone Gla Protein (BGP) levels were measured by both immunoradiometric assay (IRMA) and radioimmunoassay (RIA) to investigate the effect of intermittent 1,25(OH)2D3 administration to dialysis patients who could not tolerate an increase in an active vitamin D3 dose and/or calcium to control secondary hyperparathyroidism due to hypercalcemia. The administration of active vitamin D3 gradually increased the serum BGP to more than 3 times the original level by the 8th week. At the 12th week after starting the active vitamin D3 therapy, mean BGP was about twice the original level, which was about half the maximum level at the 8th week. The BGP (IRMA)/BGP (RIA) ratio was increased significantly at 4th and 8th weeks compared to the original level. During this period, serum calcium, phosphorous, or intact molecule PTH (I-PTH) levels showed insignificant changes, with a slight reduction in the mid molecule PTH (m-PTH) level, and a significant reduction in ALP. Serum BUN and creatinine levels were not changed significantly. These data suggest that BGP was increased through direct stimulation of osteoblasts by the active vitamin D3, and the increase was not due to deterioration of secondary hyperparathyroidism. The reduction of the increase in the BGP level at the 12th week with insignificant biochemical changes suggest that activation of osteoblasts by vitamin D3 may be transient. In conclusion, intermittent active vitamin D3 increases serum BGP, without deterioration of major biochemical changes even in patients with moderate to severe secondary hyperparathyroidism, although the increase may be transient. These facts suggest that the serum BGP of hemodialysis patients is controlled at least in part by active vitamin D3.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗
PubMed1991

Substrain comparison of genetically hypertensive rats using DNA fingerprinting, and genetic analysis of blood pressure in the inbred rats.

Using DNA fingerprinting, genetic heterogeneity or homogeneity was studied between substrains of spontaneously hypertensive rats (SHR) and Wistar-Kyoto (WKY) rats maintained in Japan. Using human myoglobin minisatellite 33.15 as a probe, we did not detect any inter- or intra-substrain genetic heterogeneities in HinfI digests of SHR or WKY rat DNA. However, analysis of Sau3AI digests of rat DNA using mouse C-6 gene as a probe revealed intra-substrain heterogeneity of 1-2 DNA bands in one of the WKY rat substrains. In the other substrains of SHR and WKY rats, there existed no intra-substrain heterogeneities, but several inter-substrain heterogeneities were observed in both SHR and WKY rats. In another experiment using the inbred substrains of SHR and WKY rats which have been confirmed as genetically homogeneous, we produced F1 and F2 rats, and biometrically analyzed their systolic blood pressure. The results suggested that there may be 1-4 dominant antihypertensinogenic genes with high heritability of 0.6-0.7.

Animals↗
PubMed1991

Effects of vitamin E-enriched egg yolk on lipid peroxidation, hemolysis and serum lipid concentration in young and old rats.

Effects of a diet containing different amount of vitamin E-enriched egg yolk powder on lipid peroxidation, hemolysis, and serum lipid concentration were examined in young and old rats. Young and old rats were fed experimental diets containing 5.6% or 22.5% of normal egg yolk powder, and 5.6% or 22.5% of vitamin E-enriched egg yolk powder. When young rats were fed these diets, their tocopherol concentrations in testes, heart, kidneys, and retroperitoneum fat pads increased according to the diet tocopherol contents. Lipid peroxide levels in these tissues were inversely proportional to the tocopherol concentrations. The liver and serum, however, did not show the above relationship. In the rats fed vitamin E-enriched egg yolk diets hemolysis did not increase, in contrast to those fed normal egg yolk diets. The rats fed a 5.6% vitamin E-enriched egg yolk diet had a lower serum cholesterol level than those fed a normal egg yolk diet. In old rats, one control group was used to determine initial tocopherol concentration and two other groups were fed 5.6% normal and vitamin E-enriched egg yolk diets. The vitamin E-enriched egg yolk rats showed lower weights of the body, liver, and retroperitoneum fat pads at the end of the experiment. The normal egg yolk group had atrophied testes. The tissue and serum tocopherol concentrations were increased in the vitamin E-enriched egg yolk group, whereas they were decreased in the normal egg yolk group. In the vitamin E-enriched egg yolk group, lipid peroxide, hemolysis and serum cholesterol, especially HDL-cholesterol, did not increase. These results indicate that egg yolk tocopherol was absorbed and prevented lipid peroxidation and hemolysis in young and old rats, and testes atrophy in old rats.

Age Factors↗
PubMed1991

Effects of dietary phosphorus restriction on secondary hyperparathyroidism in hemodialysis patients during intermittent oral high-dose 1,25(OH)2D3 treatment.

Phosphorus (P) retention plays an important role in the pathogenesis of secondary hyperparathyroidism (2nd HPT) in chronic renal failure. In recent years, periodic intravenous or intermittent oral administration of high doses of 1,25(OH)2D3 has been reported to improve severe 2nd HPT in hemodialysis patients. The present study was performed to determine the effects of dietary P restriction on 2nd HPT in hemodialysis patients treated with intermittent oral high-dose 1,25(OH)2D3. A high dose of 1,25(OH)2D3 was administered orally twice a week at the end of hemodialysis in 20 hemodialysis patients with 2nd HPT. Dietary P content was estimated from records of the patients' food intake, made twice during the treatment period. Based on this information, dietitians developed appropriate meal plans and instructed the patients. After 8 weeks of the treatment, serum c-parathyroid hormone (c-PTH) and alkaline phosphatase (ALP) levels decreased significantly, from 18.8 +/- 1.9 ng/ml and 347.1 +/- 30.7 U/liter to 9.4 +/- 1.2 ng/ml and 268.3 +/- 19.6 U/liter, respectively. Serum P levels increased gradually during the first 4 weeks of the treatment. Dietary P intake was reduced significantly, from 908 +/- 49 mg/day to 734 +/- 39 mg/day, after the nutritional instructions. As a result of the dietary P restrictions, serum P levels were significantly decreased in the 8th week as compared with those in the 4th week. Serum Ca levels remained unchanged throughout the observation period. There was a significant relationship between the mean values for serum P levels during the study and the percent suppression of serum c-PTH.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗
PubMed1991

Total and regional bone mineral content in patients with non-insulin dependent diabetes mellitus.

Total body bone mineral content and bone mineral content in various body sites were measured by dual-photon absorptiometry in 103 patients with non-insulin-dependent diabetes mellitus (NIDDM) and the findings were compared with those for 214 non-diabetic control subjects matched for age and body weight. Neither total body bone mineral content (TBBM) nor the bone mineral density of the third lumbar vertebra (L3 BMD) in the diabetic subjects differed from the values in control subjects of either sex, but the values were significantly decreased in patients diseased for at least five years when compared with control subjects. Regional bone mineral measurement showed prominent bone loss in the truncal site, but no reduction in bone mass was found in the head, pelvis, arms, or legs in either male or female patients. These results suggest that reduced TBBM and L3 BMD are associated with duration of the disease and that a site-specific bone defect is present in NIDDM.

Adult↗
PubMed1991

Calcium metabolism in diabetes mellitus.

Calcium metabolism was studied in patients with diabetes mellitus. Information on the dietary intake of major nutrients was gathered from 23 non-insulin-dependent diabetic patients, 42 insulin-dependent diabetic patients and 245 nondiabetic patients under hemodialysis through a questionnaire. A calcium absorption test was performed, using an isotopic technique, in 11 non-insulin-dependent diabetic patients and 4 age-matched healthy subjects. Parathyroid function was examined, using oral phosphate loading, in 6 diabetic patients and 6 age-matched control subjects. The daily dietary intake of calcium in the non-insulin-dependent diabetic patients (602 +/- 52 mg) was up to the average daily nutritional requirement (600 mg). The calcium absorption rate in these patients (54.4 +/- 13.9%) was similar to that in the healthy subjects (50.1 +/- 5.4%). The response of parathyroid hormone to phosphate loading was significantly reduced in the diabetic patients compared to the control subjects. The results suggest that calcium homeostasis in diabetic patients with normal renal function is almost conserved, despite the decreased response of parathyroid hormone to phosphate loading.

Administration, Oral↗
PubMed1991

Obesity as a determinant of regional bone mineral density.

Total body and regional bone mineral density (BMD) and bone mineral content (BMC) in obese patients and healthy controls were assessed by dual-photon absorptiometry (DPA) in this study. In both men and women, BMD values in total body, pelvis, upper and lower extremities were significantly (p less than 0.05) higher in the obese group (body mass index greater than 28) than in the non-obese group (body mass index less than 23). These BMD values correlated significantly with body weights and with percentages of body fat. In the obese group, 8 massively obese women were treated with an 8-week very low calorie diet (VLCD), resulting in a 13.4 kg of mean body weight reduction. Although BMC in total body and in pelvis were maintained, significant decreases of BMC in the upper (from 275 +/- 30 to 255 +/- 26 g) and lower (from 871 +/- 47 to 805 +/- 31 g) extremities were observed following the 8-week VLCD treatment. These results suggest that body fat mass affects BMD and BMC preferentially in weight bearing bone, the changes of which are not always associated with changes in total body BMD or BMC.

Adult↗
PubMed1991

YS-822A, a new polyene macrolide antibiotic. II. Planar structure of YS-822A.

The planar structure of a new polyene macrolide antibiotic, YS-822A, which was isolated from the culture filtrate of a mutant strain H-8 of Streptoverticillium eurocidicum var. asterocidicus S-822, was established as I on the basis of spectroscopic evidences and by comparison spectroscopic data with nystatin A1 (II) and amphotericin A (III), representative polyene macrolide antibiotics. Molecular formula of YS-822A was established as C37H59NO14 (MW 741) by elemental analysis, NMR, and FAB mass spectra. The UV spectrum of YS-822A was very similar to that of nystatin A1, suggesting that YS-822A also has a conjugated all-trans-tetraene moiety. 1H and 13C NMR spectra of YS-822A showed a number of broad and overlapped signals, but the 1H-1H and 13C-1H COSY spectra implied the existence of a mycosamine moiety and several other partial structures. The connectivity of these partial structures was established by extensive 2D NMR experiments, including homonuclear Hartmann-Hahn and heteronuclear multiple-bond connectivity measurements, which led to the determination of the gross planar structure of YS-822A as I.

Amphotericin B↗
PubMed1991

Tight linkage of the ret proto-oncogene with the multiple endocrine neoplasia type 2A locus.

The ret proto-oncogene has been mapped to 10q11.2 near the MEN2A locus by in situ hybridization. We carried out a linkage study of Japanese multiple endocrine neoplasia type 2A (MEN2A) families using a cosmid clone containing the ret proto-oncogene as probe. Two polymorphic alleles (A1 and A2) could be detected by digesting DNA with EcoRI: allele A1 was detected as a 10 kb fragment and A2 as 5.4 and 4.6 kb fragments. Of 11 Japanese MEN2A families analysed, four were informative, and the maximum lod score was 4.23 at a recombination fraction of 0.00. This result suggests the ret proto-oncogene to be close to the MEN2A gene and therefore possibly to be a useful DNA marker for cloning the latter.

Chromosome Mapping↗
PubMed1991

[Combination chemotherapy with ifosfamide (or cyclophosphamide), adriamycin, cis-platinum and peplomycin (IAPP) for hormonally resistant metastatic prostatic cancer].

From January, 1986 to April, 1990, combination chemotherapy with ifosfamide (or cyclophosphamide), adriamycin, cis-platinum and peplomycin was performed in 15 patients with hormonally resistant metastatic adenocarcinoma. Three patients had partial response (PR) and 9 remained objectively stable (ST). The median response duration of PR + ST (12) was 5.7 months (range 2.8 to 18.0+). Three patients progressed while on this therapy. Of 8 patients with prior treatment of chemotherapy or chemo-hormonal therapy, 6 achieved an objective response (2 PR, 4 ST). Severe toxicities occurred in 2 patients. One died of lung fibrosis induced by peplomycin and the other received urinary diversion for persistent hemorrhagic cystitis. These results compare favorably with previous reports of chemotherapy treatment of metastatic prostatic cancer patients who failed on hormonal manipulation. However, careful treatment is needed for lung fibrosis and hemorrhagic cystitis.

Aged↗
PubMed1991

Metal- and photo-induced cleavage of DNA by podophyllotoxin, etoposide, and their related compounds.

Podophyllotoxin (PD) and its derivative etoposide (VP-16), a clinically useful anticancer drug, exhibit different mechanisms of action. PD binds specifically to tubulin to prevent its polymerization, whereas VP-16 lacks this action. The DNA strand breakage caused by VP-16 is thought to be due to its interaction with topoisomerase II or to free radical formation by oxidation of its 4'-phenolic hydroxyl group to a semiquinone free radical. We have demonstrated that PD, VP-16, 4'-demethylepipodophyllotoxin (DEPD), and syringic acid (SA) exhibit no DNA-cleaving activity but, in the presence of metal ions such as Cu2+ and Fe3+, DEPD and SA form metal complexes, which in turn show high activity for DNA strand scission at pH 7.8 under air. Furthermore, it was found that DNA cleavage was greatly promoted by irradiation with UV light. The PD-Fe3+ system at pH 7.8 showed very low DNA-cleaving activity, but irradiation with UV light in the system induced almost complete DNA breakage. DNA cleavages were significantly inhibited in the presence of hydroxyl radical scavengers, such as sodium benzoate and dimethylurea, in the Cu(2+)-SA and Fe(3+)-PD systems, with or without UV irradiation. These reactions were investigated by optical and ESR spectra, coupled with ESR spin-trapping techniques, by which the formation of hydroxy radicals was clearly detected in all systems. These findings have led us to a new proposal of the metal- and photo-induced mechanism for understanding the antitumor action of PD, VP-16, and their related compounds.

DNA↗
PubMed1991

[Incontinent urinary diversion].

We analyzed 237 patients who underwent total cystectomy with ileal conduit urinary diversion or cutaneous ureterostomy at the Center for Adult Diseases, Osaka. One-hundred and eighty-eight patients underwent ileal conduit diversion and 49 patients underwent cutaneous ureterostomy. No patient died within 30 days after the operation, but two patients who underwent ileal conduit diversion died of postoperative complications within 2 months. Early complications occurred in 94 patients (50%) in the ileal conduit group and in 18 patients (37%) in the ureterostomy group. Late complications occurred in 85 patients (45%) in the ileal conduit group and in 23 patients (47%) in the ureterostomy group. Frequent early complications in the ileal conduit group were wound infection (29%), and intestinal complications (13%) which included ileus and upper urinary tract complications (12%). The most frequent late complications were stomal complications (26%) which included peristomal dermatitis stomal stenosis, parastomal hernia, and stomal prolapse, and upper urinary tract complications which were noted in 27 patients (14%).

Aged↗
PubMed1991

Effects of indocyanine green dye enhanced diode laser photocoagulation in non-pigmented rabbit eyes.

Dye enhanced photocoagulation using indocyanine green (ICG) and diode laser has recently been introduced for occlusion of the choroidal neovascular tissue of age-related maculopathy. However, the effects of photocoagulation generated only by dye enhancement have not yet been studied. To discover the threshold amount of ICG for the minimum effect of photocoagulation, various photocoagulation parameters were tried in the fundus of albino rabbit. That is to say, ICG dosage laser power and exposure time were varied at the range of 0.5 mg to 14.0 mg/Kg, 80 to 500 mW and 0.2 or 1.0 sec, respectively. Histopathologic evaluation revealed that the effect of the enhanced photocoagulation was more marked in the choroid than in the retina, and was particularly noticeable in the large vessels in the deep layer of the choroid, even in lower threshold lesions. In clinical application, we should take into consideration the excessive reaction in the choroid.

Animals↗
PubMed1991

[Effects of verapamil on the left ventricular diastolic function and diastolic asynchrony in patients with hypertrophic cardiomyopathy].

The effects of verapamil on the diastolic function and regional asynchrony of the left ventricle were echocardiographically investigated in 37 patients with hypertrophic non-obstructive cardiomyopathy (HCM). Before and 20 min after the intravenous administration of verapamil (0.1 mg/kg), blood pressure (BP), heart rate (HR), transmitral pulsed Doppler indices (R, A, A/R), M-mode echo indices (Dd, Ds, %FS) and the echo-phonocardiographic index (isovolumic relaxation time; IRT) were measured. We also measured the rapid extension times of the posterior walls at the chordae and papillary muscle level [Tc(pw), Tp(pw)] as the indices of regional diastolic function, and their difference [Tp-c(pw)] was used as the index of diastolic asynchrony. Before verapamil administration, the HCM patients had significantly larger A, A/R, IRT and Tp-c(pw) and smaller R than did 20 healthy controls, but showed no significant differences in HR, BP, Dd, Ds and %FS. After verapamil injection, R increased and A, A/R, IRT, Tp-c(pw) decreased significantly without any changes in BP and HR. The increment of R (delta R) correlated significantly with the decrement of Tp-c(pw) (r = -0.66, p less than 0.001). According to the value of delta R/R, 37 patients with HCM were categorized in 2 groups (19 responders with delta R/R greater than or equal to 10% and 18 non-responders with delta R/R less than 10%). The responders had smaller R and larger A/R, IRT and Tp-c(pw) before verapamil administration than did the non-responders. Verapamil increased R, Dd, Ds and decreased A, A/R and Tp-c(pw) in the responders, but not in the non-responders. These results suggested that verapamil might improve left ventricular diastolic function in HCM patients through the improvement of left ventricular diastolic asynchrony.

Adult↗