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Biomedical subjects

K Nakane

Publications and source records attributed to K Nakane.

At least 37 records · Page 2Linked to original sources
PubMed1991

Quantitative measurement of regional cerebral blood flow with I-123 IMP SPECT: a correction of the microsphere model by global extraction between artery and internal jugular vein.

Quantitative measurements of regional cerebral blood flow with N-isopropyl-(Iodine 123)p-iodoamphetamine (I-123 IMP) as a microsphere model were performed in forty cases. The regional cerebral blood flow values obtained with I-123 IMP were slightly underestimated compared with those of Xe-133 inhalation methods (y = 0.90x-2.1, r = 0.85, p less than 0.01). After correction by global extraction (87%) between the artery and internal jugular vein, which was measured in four patients by means of a catheter technique, the underestimation of the values obtained with I-123 IMP was improved (y = 1.0x-2.4, r = 0.85, p less than 0.01). Several problems in the accurate quantitative measurement of regional cerebral blood flow with I-123 IMP are discussed.

Adult↗
PubMed1990

Occurrence and character of a putative causative virus of enterically-transmitted non-A, non-B hepatitis in bile.

The present investigation confirms the possibility that the etiological agent of enterically-transmitted non-A, non-B (ET-NANB) hepatitis (type E hepatitis), multiplied in hepatocytes, is excreted into the feces via bile. The fecal extract was inoculated into 7 cynomolgus monkeys. Bile juice was collected directly from the gallbladder by needle puncture after abdominal operation 3 to 6 times during the experimental course. All 7 monkeys developed elevated serum aminotransferases, which began gradually approximately 2 weeks postinoculation and reached a peak at 3 to 5 weeks. In parallel with this elevation, both in time and magnitude, necroinflammation was observed in the livers. The virus-like particles (VLPs) were found in the bile juice of all 7 monkeys and the serial occurrence of VLPs was typified as follows: the VLPs were negative on day 7, appeared on day 10 after inoculation, and were present until the 3rd week when the subjects were sacrificed. While the particles were individually dispersed on day 10, they started to exhibit spontaneous aggregation on and after week 2. Also, empty particles were very rare at first, but increased in ratio compared to full ones over time. Thus, the putative causative virus of ET-NANB hepatitis was demonstrated to be excreted through bile. The spontaneous aggregation of VLPs might be due to the specific antibody secreted into the bile juice and was closely correlated with hepatitis activity. The increase in empty particles might indicate an increase in disorganized assembly of the nucleic acid and protein during virus proliferation.

Animals↗
PubMed1990

Morphological features of blood access stenosis and results of noninvasive angioplasty.

We investigated a connection between the results of noninvasive angioplasty for the blood access stenosis and its morphological features in 37 dialysis cases. In 3 cases presenting stenosis in the original artery, the area could not be dilated by noninvasive techniques. In 4 cases with stenosis in the arterialized vein downstream of the needle insertion points for extracorporeal circulation, 3 showed long-term dilatation by the procedures. In 30 cases having stenosis upstream of the points, 16 showed long-term dilatation. In the unsuccessful cases, the angle formed between the axes of the stenosed portion and the normal vessel was over 39 degrees, and the distance between the anastomosis and the stenosed portion was less than 11 mm.

Angioplasty, Balloon↗
PubMed1987

Enzymatic determination of bilirubin fractions in serum.

Novel enzymatic methods using bilirubin oxidase from Myrothecium verrucaria are described for the determination of bilirubin fractions in serum. These fractions include an unconjugated form (Bu), a conjugated form (Bc), and a delta fraction of bilirubin that reacts with direct diazo reagent and is irreversibly bound to serum albumin (B delta). The determination is based on the different reactivities of the enzyme to bilirubin fractions at different pH in the presence or absence of anionic detergent such as sodium dodecyl sulfate (SDS) or sodium cholate. Thus, in the absence of detergents, Bc and B delta are oxidized at acidic pH, while Bc is oxidized at alkaline pH; Bu is not oxidized at either acidic or alkaline pH. The first approach is based on measuring the decreased absorbance of bilirubin colour at 450 nm caused by the enzymatic oxidation. Total bilirubin is measured at pH 8.0 in the presence of SDS. Direct bilirubin is measured at pH 3.7 and Bc is measured at pH 10.0 in the absence of SDS, respectively. The second approach is made by coupling the diazo reaction with the enzyme reaction. Total and direct bilirubin are determined by a conventional diazo method without prior treatment by the enzyme. B delta is determined with a direct diazo method after the serum sample is treated at pH 10.0 by the enzyme to oxidize the Bc fraction. The precision and the accuracy of these methods were compared with a diazo method, an HPLC method and a slide method, and good results were obtained.

Bilirubin↗
PubMed1986

Effect of maternal urethane administration on the manifestation of cleft lip and palate in CL/Fr mice.

To determine whether the administration of urethane also decreases the associated cleft palate in CL/Fr mice, pregnant CL/Fr mice (30% of their offspring have spontaneous cleft lip with associated cleft palate [CL/P]) were treated with various doses of urethane on different days of pregnancy. In the groups treated with 250, 500, and 750 mg/kg urethane on day 9 of pregnancy, the frequency of CL/P decreased with the dose to 18%, 14%, and 11% of term fetuses, respectively. In the group treated with 1,000 mg/kg urethane on day 9, the frequency of CL/P decreased to 6%, but isolated cleft palate (CP) was observed in 23% of term fetuses. Most fetuses in the same group had severe tail anomaly (absence of tail or stub tail), and showed marked loss in body weight. The CP observed in the group treated with 1,000 mg/kg urethane on day 9 might possibly be due to the teratogenicity of the drug.

Animals↗
PubMed1977

Amino acid modulation of glucose-induced insulin and glucagon release in diabetic patients.

In order to determine whether amino acids have a beneficial effect on glucose tolerance in diabetes, the effect of intravenous infusion of mixed amino acids on plasma insulin, glucagon, and blood glucose responses to oral glucose loading was studied in patients with mild to moderate diabetes. Intravenous infusion of mixed amino acids over a period of 30 min which was started 30 min or immediately before oral glucose loading significantly augmented the insulin response but did not improve the blood glucose curve, probably due to excessive glucagon response. However, amino acid infusion over a period of 60 min started immediately before oral glucose loading evoked a sustained rise of plasma insulin associated with a lesser degree of glucagon secretion, thus causing significant improvement of the blood glucose curve.

Adult↗
PubMed1976

Localization of cell groups sensitive to parathyroid hormone and calcitonin in rat skeletal tissue.

The level of cyclic AMP in various fractions of rat skeletal tissue was measured after in vitro or in vivo administration of parathyroid hormone and calcitonin. Incubations of bone fractions prepared from young (5 weeks of age thyroparathyroidectomized rats revealed that both parathyroid hormone and calcitonin increased the cyclic AMP level in fractions of epiphysis, metaphysis and marrow cells. Cyclic AMP accumulation in incubated perisoteum and diaphysis were induced solely by parathyroid hormone. In in vivo experiments the cyclic AMP level in the tibia of the thyroparathyroidectomized rat was increased by infusion of either parathyroid hormone or calcitonin, and the simultaneous administration of each maximally effective dose of the two hormones exhibited an additive effect. Within 2 min, parathyroid hormone infusion caused an elevation of cyclic AMP content in periosteum and metaphysis. Rapid increase of cyclic AMP in the metaphysis was also induced by calcitonin, and the effect of the two hormones on cyclic AMP accumulation in this fraction was additive. Small but significant increase of cyclic AMP in the diaphysis was detected at 5 min after the administration of parathyroid hormone. Calcitonin infusion did not show any consistent effects on periosteum and diaphysis.

Animals↗
PubMed1975

The hypercalcemic effect of parathyroid hormone and skeletal cyclic AMP.

The effects of parathyroid hormone (PTH) on bone mineral mobilization are thought to involve the second messenger cyclic AMP. Intravenous administration of 10 U PTH induced rapid and marked accumulation of cyclic AMP in calvaria and plasma of thyroparathyroidectomized rats. The changes in cyclic AMP concentrations were not sustained, but returned to near-baseline values before the rise in plasma calcium concentration was manifest. Changes in the plasma levels of calcium and cyclic AMP in response to PTH infusion were demonstrated in thyroparathyroidectomized rats who were nephrectomized as well. In a series of experiments to clarify the association of cyclic AMP accumulation and calcium mobilization, it was found that small doses of PTH induced significant elevation of plasma calcium without stimulating an accumulation of cyclic AMP in calvaria, or plasma. Furthermore, in intact rats plasma calcium levels were elevated by endogenous PTH, provoked by EGTA induced hypocalcemia, without any demonstrable change of cyclic AMP metabolism in the skeletal tissue. At a higher dose of PTH, the magnitude of the integrated change of cyclic AMP metabolism in the skeletal tissue was well correlated to the amount of calcium mobilized. These observations indicate a coupling between enhanced production of cyclic AMP and calcium mobilization in the action of PTH on bone. They also suggest that either a minute change in cyclic AMP accumulation, which can not be detected due to a high basal level of this nucleotide in the tissue, or a change in metabolism of cyclic AMP in some particular cell compartment is an early event in PTH-induced calcium mobilization.

Acetates↗
PubMed1975

Effect of porcine calcitonin on the metabolism of calcium and cyclic AMP in rat skeletal tissue in vivo.

Infusion of 50 mU/100 g body wt of calcitonin induced a rapid and marked increase of cyclic AMP in calvaria as well as in plasma of thyroparathyroidectomized rats. These changes preceded the decrease in plasma calcium concentration seen after hormone administration. The possible relationship of this stimulation of cyclic AMP accumulation to the hypocalcemic effect of calcitonin was examined under several experimental settings. It was found that a dose of calcitonin sufficient to cause a significant decrease of plasma calcium failed to produce any detectable accumulation cyclic AMP in calvaria, but when high doses of calcitonin were given, there was an apparent correlation between the integrated change of cyclic AMP metabolism and the duration and magnitude of hypocalcemia. Experiments employing the ophylline and imidazole, which alter cyclic AMP metabolism, led to an apparent dissociation between the hypocalcemic effect of calcitonin and its stimulation of cyclic AMP accumulation in bone.

Animals↗