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Biomedical subjects

M Kubota

Publications and source records attributed to M Kubota.

At least 361 records · Page 20Linked to original sources

Effects of ML-9 on insulin stimulation of glucose transport in 3T3-L1 adipocytes.

Treatment of 3T3-L1 adipocytes with insulin resulted in activation of 2-deoxyglucose transport activity and translocation of glucose transporters (GLUT4 and GLUT1) from the cytoplasmic space to the plasma membrane. ML-9 (a myosin light chain kinase inhibitor) inhibited insulin stimulation of 2-deoxyglucose transport activity by 80% at 100 microM (IC50 = 27 microM) without affecting 2-deoxyglucose transport activity in the basal state. The inhibition was independent of extracellular Ca2+ concentration and almost fully reversible at 40 microM ML-9. ML-9 did not inhibit insulin-stimulated tyrosine phosphorylation of 95-kDa protein in the wheat germ agglutinin-purified preparation and of 95- and 160-kDa proteins in intact cells. However, ML-9 inhibited insulin-induced translocation of both GLUT4 and GLUT1 in a dose-dependent manner. The dose-response curves were similar to those observed for the inhibition of insulin stimulation of 2-deoxyglucose transport activity. Neither insulin nor ML-9 affected the phosphorylation state of both heavy and light chains of myosin. Therefore, it seems likely that ML-9 inhibits the insulin-induced translocation of glucose transporters at a step beyond the insulin receptor kinase activity by a mechanism different from that affecting phosphorylation of the myosin light chain. Phosphorylating activity of microtubule-associated protein 2 and myelin basic protein was stimulated by insulin, and this stimulation was not affected by ML-9. ML-9, however, inhibited the phosphorylating activity in vitro and insulin stimulation of the phosphorylating activity of ribosomal protein S6 in intact cells in a dose-dependent manner similar to that observed for the inhibition of insulin stimulation of glucose transport. These results suggest that mitogen-activated protein kinase may be one of the constituents in intracellular insulin signaling to the glucose transport system.

3T3 Cells↗

Specific activity of phosphatidylinositol 3-kinase is increased by insulin stimulation.

We investigated whether phosphatidylinositol 3-kinase (PI3K) is phosphorylated and whether its specific activity is increased by insulin stimulation in vivo using Fao cells and antibodies raised against the 85 kDa subunit of PI3K, insulin-receptor substrate-1 (IRS-1), and phosphotyrosine (pTyr). PI3K activity was detected in the immunoprecipitate produced with anti-PI3K at a basal state. The activity was increased 2-3-fold by insulin stimulation, although the protein concentration of kinase in the anti-PI3K immunoprecipitates was the same before and after insulin stimulation. Both anti-pTyr and anti-IRS-1 antibodies immunoprecipitated the kinase activity only after insulin stimulation. After the first immunoprecipitation with anti-pTyr, the supernatant was immunoprecipitated once more with anti-PI3K. PI3K activity in the second immunoprecipitate revealed little difference between the basal and insulin-stimulated states, suggesting that most of the insulin-activated portion of PI3K was precipitated by anti-pTyr. Both IRS-1 and the insulin-receptor beta-subunit (95 kDa) were phosphorylated on tyrosine residues by insulin stimulation and immunoprecipitated with anti-pTyr. However, phosphorylation of neither subunit of PI3K (85 kDa or 110 kDa) was detectable in the immunoprecipitate produced with anti-pTyr. The 185 kDa pTyr-containing protein was immunoprecipitated with anti-PI3K after insulin stimulation, although there was little phosphorylation of the 85 kDa protein. pTyr in the 110 kDa protein immunoprecipitated with anti-PI3K was below detectable levels. These results indicate that the specific activity of PI3K is increased by insulin stimulation without detectable tyrosine phosphorylation of PI3K itself in Fao cells. The majority of the insulin-activated portion of PI3K is associated with pTyr-containing proteins including IRS-1, which suggests that this is important for activation of PI3K by insulin.

Animals↗

The unusual development of empyema with multiple alveolobronchiolar fistulae 8 years after non-curative resection and radiation for lung cancer: report of a case.

We present herein the case of a man who developed empyema with multiple lung fistulae 8 years after receiving postoperative radiation for a residual tumor on the bronchial stump. The patient was successfully managed with two-stage surgery, involving an open window thoracotomy, followed by omental flap transfer. This case documents how postoperative radiotherapy that was effective following non-curative resection was also responsible for the development of empyema. Furthermore, although the empyema was successfully treated using the omentum, a small free space remained in the thorax, which resolved within 2 months.

Aged↗

Usefulness of anaerobic threshold for evaluating daily life activity and prescribing exercise to the healthy subjects and patients.

Forty-three subjects were studied as for the relationship between anaerobic threshold (AT) and medical data including individual life style. Age, habit of exercise, and obesity are related to AT, showing a correlation coefficient of 0.533, 0.457 and 0.428, respectively. On the other hand, plasma lipid levels and alcohol are not so strongly related to AT, showing low correlation coefficient of 0.241 and 0.209 respectively. No correlation is found on the other factors such as FBS, Liver and blood pressure etc. Physical active life, commuting time, cumulative exercise hours in a month and work hours in a month are correlated to AT, showing correlation coefficient of 0.799, 0.734, 0.708 and 0.671, respectively, and even "more than once a month" frequency of exercise has affected AT. In conclusion, AT is a useful index for evaluating daily life activity and prescribing exercise regimen.

Activities of Daily Living↗

IgG4 deficiency with Rothmund-Thomson syndrome: a case report.

We describe a patient with Rothmund-Thomson syndrome and IgG4 deficiency. In vitro examination of his peripheral mononuclear cells revealed impaired IgG4 synthesis. Susceptibility to sinus and pulmonary infections was cured by monthly immunoglobulin infusions.

Child, Preschool↗

Postoperative MRI evaluation of anorectal malformations with clinical correlation.

Sixteen postoperative patients with anorectal malformation were evaluated by MRI, and the results compared with the clinical assessment. Patients were classified into three groups--good (group 1, n = 10), fair (group 2, n = 3) and poor (group 3, n = 3)--on the basis of Kelly's clinical score of incontinence. The degree of development of the puborectalis and external sphincter muscles and the levator hammock was evaluated on MRI in comparison with patients without anorectal disease. The proportions of fair or poor development of the muscles were 37% in group 1,22% in group 2 and 67% in group 3. Although fair or poor development of the muscles was seen more frequently in group 3, there was no statistically significant difference between groups. However, poorly developed muscles were seen only in patients with fair or poor clinical scores. The difference in the anorectal angle measured on sagittal MRI images between patients in group 1 and groups 2 or 3 was significant. Our study indicates that MRI evaluation based solely on muscle development can be misleading, and measurement of the anorectal angle should be included in the MRI evaluation.

Abnormalities, Multiple↗

Optimization of Butterworth filter for brain SPECT imaging.

A method has been described to optimize the cutoff frequency of the Butterworth filter for brain SPECT imaging. Since a computer simulation study has demonstrated that separation between an object signal and the random noise in projection images in a spatial-frequency domain is influenced by the total number of counts, the cutoff frequency of the Butterworth filter should be optimized for individual subjects according to total counts in a study. To reveal the relationship between the optimal cutoff frequencies and total counts in brain SPECT study, we used a normal volunteer and 99mTc hexamethyl-propyleneamine oxime (HMPAO) to obtain projection sets with different total counts. High quality images were created from a projection set with an acquisition time of 300-seconds per projection. The filter was optimized by calculating mean square errors from high quality images visually inspecting filtered reconstructed images. Dependence between total counts and optimal cutoff frequencies was clearly demonstrated in a nonogram. Using this nomogram, the optimal cutoff frequency for each study can be estimated from total counts, maximizing visual image quality. The results suggest that the cutoff frequency of Butterworth filter should be determined by referring to total counts in each study.

Brain↗

Analysis of hprt gene mutation following anti-cancer treatment in pediatric patients with acute leukemia.

We evaluated the genotoxic effect of cancer therapy on somatic cell mutation by isolating 6-thioguanine-resistant mutants in peripheral lymphocytes. The study population comprised 45 children with acute lymphoblastic leukemia (ALL), 13 children with acute myelogenous leukemia (AML) and 28 age-matched healthy controls. The geometric mean mutant frequency for ALL patients was 7.8 x 10(-6), which was significantly higher than that for AML patients (1.7 x 10(-6)) or for healthy controls (1.1 x 10(-6)). Fifteen patients with ALL showed a high mutant frequency above 10 x 10(-6), although 10 of them had completed their treatment at least 24 months earlier. Moreover, repeated measurements of mutant frequency at intervals of 12 or more months revealed that the values were very stable. Structural hypoxanthine-guanine phosphoribosyl transferase (hprt) gene alterations, as determined by Southern blot analysis, were seen in 23% (12/52) of mutant clones derived from ALL patients, but not in those from the controls. These results suggest that intensive anti-cancer therapy of children may produce persistent somatic mutations, which could be related to the appearance of second neoplasms.

Adolescent↗

Improvement in blunted glucagon response to insulin-induced hypoglycemia by strict glycemic control in diabetics.

To elucidate the mechanism of impaired pancreatic A cell function in hypoglycemia in diabetics, the effect of long-term strict glycemic regulations on hypoglycemia-induced glucagon secretion was studied. Firstly, the effect of plasma insulin concentrations on suppressing A cell was studied in healthy volunteers by injecting insulin at doses of 0.1 U/kg and 0.3 U/kg. With 0.3 U/kg of insulin, the rate of fall in glycemia and the nadir of blood glucose were made similar to those with 0.1 U/kg of insulin by glucose infusion with artificial endocrine pancreas. Plasma glucagon response after 0.3 U/kg of insulin was significantly suppressed as compared to that after 0.1 U/kg of insulin, demonstrating that not only hypoglycemic stimulus but also plasma insulin concentration were important determinants responsible for glucagon secretion in insulin-induced hypoglycemia. Secondly, effect of strict glycemic control was studied. Short-acting insulin at a dose of 0.1 U/kg was injected in an intravenous bolus form into 12 insulin-dependent (IDDM) and 9 non-insulin-dependent (NIDDM) diabetics before and 1-3 months after strict glycemic control with multiple insulin injections therapy. Before strict glycemic regulations in IDDM, no significant rise in plasma glucagon concentrations was observed during the insulin-induced hypoglycemia. In NIDDM, a rise in plasma glucagon concentrations was observed, though the response was delayed. After strict glycemic regulations, in patients with residual endogenous insulin secretion, the glucagon response to hypoglycemia improved considerably in IDDM and normalized in NIDDM. In IDDM and NIDDM, improvement in glucagon response to hypoglycemia related positively to daily urinary secretion rate of C-peptide.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

Clinical usefulness of a non-wiping type glucose meter in diabetic patients.

A non-wiping type glucose meter using electrochemistry was developed. The glucose sensor strip has a sophisticated micro-structure for aspirating blood automatically. The meter compensates for drift of sensor output due to temperature change of the atmosphere. Mounting blood on the sensing site and wiping blood and precise time are no longer required. Range of measurement is 40-500 mg/dl. Reading of the meter for standard solutions of 90 or 360 mg/dl glucose showed negligible drift of measurement from 10.5 degrees C to 38.5 degrees C. The correlation between plasma glucose concentrations as determined by the meter and that by a Glucose Analyzer 2 was 0.995 with a slope of 1.00 and intercept of -0.65 (n = 48). In the case of blood glucose concentration (Y), the values were Y = 1.06X-0.91, r = 0.987, n = 62. This meter is quite easy to use and is highly accurate for glucose monitoring in patients regardless of operation skill. It should thus be readily applicable to diabetic patients.

Blood Glucose↗

Dipyridamole-provoked chest pain implies severe coronary artery disease in children.

The diagnostic significance of dipyridamole-provoked chest pain was studied in 17 children with severe coronary arterial stenotic lesions (CAL) complicated with Kawasaki disease. Although dipyridamole induced chest pain in seven patients (symptomatic group), 10 reported no pain (asymptomatic group). In the asymptomatic group, seven children had one vessel disease (1 VD) of right coronary artery (RCA) and the other three had two vessel disease (2 VD) involving the RCA and left anterior descending artery (LAD). Four multivessel disease patients, one three vessel disease (3VD) and three 2VD of LAD and RCA, and three 1VD of LAD, were symptomatic. In the thallium scans, all patients, except two of the asymptomatic group, showed perfusion abnormalities. In addition, the extent score of the symptomatic group was significantly worse than that of the asymptomatic group (P = 0.01). While only one in six of the asymptomatic group showed abnormal ST depression on treadmill exercise electrocardiography, all patients in the symptomatic group (P = 0.02) showed ischemic ST depression. These findings suggest that the occurrence of chest pain after medication with dipyridamole closely correlates with the severity of CAL in children.

Adolescent↗

Effect of parathyroid-hormone-related protein on sodium-dependent phosphate transport in renal brush border membrane vesicles in rats. Comparison with parathyroid hormone.

Parathyroid-hormone-related protein (PTHrP) has significant homology with parathyroid hormone (PTH) in the amino-terminal region. We compared the effects of synthetic human PTHrP [hPTHrP(1-34)] on Na(+)-dependent phosphate transport with those of synthetic human PTH [hPTH(1-34)]. Intravenous administration of hPTHrP(1-34) in parathyroidectomized rats caused hypercalcemia, hypophosphatemia and phosphaturia to the same degree as hPTH(1-34). In kinetic studies using renal brush border membrane vesicles, the apparent Km and Vmax of phosphate transport were identical for the two peptides [hPTHrP(1-34): Km 27.6 +/- 0.8 microM, Vmax 3.78 +/- 0.04 nmol/mg protein, hPTH(1-34): Km 29.6 +/- 0.9 microM, Vmax 3.04 +/- 0.90 nmol/mg protein]. Both hPTHrP(1-34) and hPTH(1-34) at a supramaximal dose were equipotent in eliciting a 12-fold increase in cyclic adenosine 3',5'-monophosphate (cAMP) production in the kidney. These results indicate that, in addition to the similar effect of hPTHrP(1-34) and hPTH(1-34) on serum calcium levels and urinary phosphorus and nephrogenous cAMP excretion in vivo, these two peptides have similar effects of Na(+)-dependent phosphate transport in brush border membrane vesicles in vitro.

Animals↗

[Industrial hygienic study on nursing activities. II. Investigation on heart rate and energy expenditure of ward nurses on shift].

By using a Holter electrocardiograph (ECG), we calculated the heart rates of ward nurses on day shift which included different activities. Energy expenditure was calculated from the heart rate data and nurse work load was evaluated. The following results were obtained. 1) Average heart rates during working hours were 86 (beats/min) in children ward nurses, 77 in ophthalmology ward nurses, 85 in surgery ward nurses, 85 in mixed ward nurses, 85 in neurosurgery ward nurses, 81 in circulatory organs ward nurses and 83 in ICU ward nurses. 2) The energy expenditures were calculated to be 1,891 kcal in children ward nurse on day shift, 1,866 kcal in ophthalmology ward nurses, 1,969 kcal in surgery ward nurses, 1,899 kcal in mixed ward nurses, 1,976 kcal in neurosurgery ward nurses, 1,873 kcal in circulatory organs ward nurses and 1,744 kcal in ICU ward nurses. 3) The highest energy expenditures in direct nursing care were 918 kcal (48.3%) in mixed ward nurses; in assisting medical examination and treatment, 770 kcal (39.1%) in surgery ward nurses and in indirect nursing care, 679 kcal (35.9%) in children ward nurses. 4) The longest working hours in direct nursing care were 217 min (42.5%) in neurosurgery ward nurses; in assisting medical examination and treatment, 193 min (37.8%) in surgical ward nurses and in indirect nursing care, 207 min (40.5%) in children word nurses. The results indicated that the energy expenditure calculated from the average heart rate of ward nurses on day shift was very high in all wards. The attributable causes are discussed in this report.

Adult↗

Mechanism of enhancement of neutrophil survival by granulocyte colony-stimulating factor and adenine.

An in vitro study was performed on the effect of recombinant human granulocyte colony-stimulating factor (rhG-CSF) and adenine on the survival of purified human neutrophils. The addition of rhG-CSF (1 to 100 ng/mL) or adenine (100 microM) enhanced the survival of neutrophils. The maintenance of O2- production in response to N-formylmethionyl-leucyl-phenyl-alanine (FMLP) suggested that these neutrophils were functionally alive. Neutrophils in cultures had shown two distinct biochemical changes during cell death: DNA fragmentation and depletion of cellular adenosine triphosphate (ATP) pools. Treatment with rhG-CSF (10 ng/mL) significantly delayed the appearance of DNA fragmentation as measured quantitatively by diphenylamine or by agarose gel electrophoresis. On the other hand, adenine had no effect on the generation of DNA fragmentation. The decrease of ATP during incubation for 12 hours was similar in control and rhG-CSF-treated neutrophils, while rhG-CSF prevented the further decline of ATP seen in control cultures. In contrast, adenine (100 microM) preserved ATP at levels significantly higher than in controls at both 12 hours and 24 hours of incubation. Our results suggest that rhG-CSF and adenine promote the survival of neutrophils in vitro by different mechanisms.

Adenine↗