Search PubMed⌕ Search

Biomedical subjects

K Aoki

Publications and source records attributed to K Aoki.

At least 505 records · Page 28Linked to original sources
PubMed1993

[Postoperative hypophosphatemia in patients with cancer of the thoracic esophagus].

Postoperative phosphate dynamics were studied in 30 patients who underwent radical surgery for thoracic esophageal cancer and who were postoperatively nourished by total parenteral nutrition. There was a significant fall in the serum phosphate level on the 2nd and 3rd postoperative days in all patients. Postoperative hypophosphatemia was due to an increase in urinary phosphate excretion which was indicated by the fall in TRP% and TmPO4/GFR. A highly significant positive correlation was observed between the increase in urinary phosphate loss and the enhanced secretion of parathyroid hormone which was possibly triggered by surgical stress, a decrease in the serum level of calcium, the action of phosphate buffer or diuretics. All the patients except for those with postoperative pulmonary complications responded to the drop in serum phosphate by renal conservation of phosphate. A slight decrease in the serum level of phosphate was also found on the 6th postoperative day in most patients who were receiving parenteral hyperalimentation. The second fall in phosphate was due to transcellular shifts of phosphate. It is concluded that patients with postoperative pulmonary complications develop severe hypophosphatemia which should be prevented by replacement therapy with phosphate in the immediate postoperative period.

Calcium↗
PubMed1993

[Characteristics of plasma levels of myosin light chain I in patients under aorta-coronary bypass grafts].

After cardiac operation plasma level of ventricular myosin light chain I (LCI), determined with monoclonal antibodies to myosin fragment, were studied in 30 patients under bypass surgery to assess its possible role as a marker for perioperative myocardial injury. LCI rapidly increased and reached peak levels (15.8 +/- 9.0 gn/ml; T-peak) at 88 +/- 28 minutes after aortic declamp (T-Time). Then LCI rapidly decreased with fast half-time disappearance (1.1 +/- 0.7 hours). In 7 out of 30 patients LCI improved to normal range and MB reached maximum levels (28.8 +/- 11.9 U/L) at 6.3 +/- 2.3 hours after declamp. No abnormal change was noted in ECG and no new defects were noted in T1-201 myocardial images. In the remaining 23 patients LCI decreased to minimum levels (4.1 +/- 2.1 ng/ml; min-LCI) at 9.2 +/- 5 hours (min-Time) and then gradually increased to peak levels (8.4 +/- 5.8 ng/ml; M-peak, M-value) on day 3.3 +/- 1.0 (M-Time). MB reached maximum level (77.6 +/- 82.4 U/L, p < 0.1) at 3.4 +/- 1.4 hours (p < 0.001). Good correlation was noted among min-LCI, min-Time, M-value and summation of daily value of LCI (omega(LCI)) x min-LCI = 5.7-0.17 min-Time (r = -0.42) and M-value = 2.1 min-LCT(r=0.74) and omega(LCI) = -9.6 + 6.1 M-value (r = -0.96). From the rapid appearance of LCI peak levels after aortic declamp it was concluded that LCI, accumulated during aortic clamp, was washed out by aortic declamp.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1993

Demonstration of focal brain ischemia induced by hyperventilation using Tc-99m HMPAO SPECT.

A case with vasospasm of the right anterior cerebral artery induced by hyperventilation is presented. Consecutive Tc-99m HMPAO brain SPECT studies at rest and during hyperventilation greatly contributed to the quantitative evaluation of focal perfusion decrease in conjunction with contrast angiography. This technique seems to be useful for the detection of alterations in regional brain perfusion during short duration intervention.

Adult↗
PubMed1992

Relationship between tissue content of TC-81 and relaxation of rat aorta.

This study dealt with the relationship between the relaxant action of TC-81, a new Ca2+ antagonist, and its distribution in rat aorta depolarized by high K+ (65.4 mM). The inhibitory effect by TC-81 on K(+)-induced contraction and 45Ca2+ uptake was strongly time-dependent. TC-81 and nicardipine, each 10(-9) M, produced gradual relaxation of high-K(+)-induced contraction. The tissue contents of TC-81 and nicardipine increased with time courses that reflected decreasing tension. Both the maximum tissue content of TC-81 and the maximum relaxation were significantly greater than those for nicardipine. Also, the relaxations produced by TC-81 and nicardipine were correlated with the logarithm of the content of each drug in muscle tissues. However, the dissociation of TC-81 from the tissues was slower than that of nicardipine. The data suggest that the action of TC-81 is closely related to a gradual distribution of drug into muscle tissue, resulting in a slow onset of action. Also, the saturation time of TC-81 was longer than that of nicardipine, thereby accounting for the greater relaxation with TC-81.

Animals↗
PubMed1992

Possible role of plasminogen activator inhibitor 2 in the prevention of the metastasis of gastric cancer tissues.

The concentrations of urinary type plasminogen activator (u-PA), plasminogen activator inhibitor 1 (PAI-1), and PAI-2 were measured in gastric cancer tissues and adjacent healthy mucosal tissues. Levels of u-PA, PAI-1 and PAI-2 were higher in cancer than in control tissues. PAI-1 levels were higher together with the progression of cancer however there were no differences in u-PA or PAI-2 levels. Tumors with higher PAI-1 and lower PAI-2 levels tend to metastasize to remote lymph nodes. When the numbers of involved lymph nodes were analyzed, tumors with the large number of metastatic lymph nodes showed higher PAI-1 and lower PAI-2 level. No difference was shown in u-PA levels among these groups. These tendencies were more significant in patients with progressed gastric cancer. These results suggest that tumor with higher PAI-2 levels tend to localize or have less tendency to metastasize to lymph nodes. On the other hand PAI-1 was generally higher in tumor with invasion into nearby tissue or with nodal metastasis.

Enzyme-Linked Immunosorbent Assay↗
PubMed1992

Prognostic factors in patients with hepatocellular carcinoma receiving systemic chemotherapy.

A total of 71 consecutive patients with unresectable hepatocellular carcinoma were analyzed retrospectively to determine the significant prognostic factors. All the patients received systemic chemotherapy in a phase 2 study from 1980 to 1990, with no other anticancer treatment. Median survival time and 1-yr and 2-yr survival rates were 5.6 mo, 23% and 5%, respectively. By the univariate analysis, a performance status of 0-1 and tumor size less than 50% of the liver cross-sectional area were shown to be the factors most significantly favoring a better prognosis. By the multivariate analysis using the Cox proportional hazards model, a performance status of 0-1 (p less than 0.001), absence of tumor thrombus in the main portal trunk (p = 0.003) and age less than 60 yr (p = 0.036) were independent favorable prognostic factors. A prognostic index was calculated from these three factors according to the following equation: 1.8109 x (0 = performance status of 0-1 and 1 = performance status of 2-3) + 0.9322 x (0 = tumor thrombus absent in the main portal trunk and 1 = present) + 0.6996 x (0 = age less than 60 yr and 1 = age greater than or equal to 60 yr). This index was used to classify the patients into three groups with a good, intermediate and poor prognosis. The median survival times for these three groups were 9.8, 3.8 and 1.9 mo, respectively (p less than 0.01). The results of this study may be useful in the design and analysis of future clinical trials of systemic therapy for hepatocellular carcinoma.

Analysis of Variance↗
PubMed1992

Kallikrein-producing cells in the rat pituitary and pineal gland.

By using an immunohistochemical technique, kallikrein-producing cells in the anterior pituitary of rats were identified to be the same as prolactin-producing cells. Kallikrein was localized at the Golgi apparatus, the rough endoplasmic reticulum and secretory granules. Kallikrein was also located in the perivascular cells of the pineal gland.

Animals↗
PubMed1992

Assortative mating and grandparental transmission facilitate the persistence of a sign language.

Conditions for the persistence (i.e., protection from loss) of a sign language are investigated assuming monogenic recessive inheritance of deafness, assortative mating for deafness or hearing, and cultural transmission of the sign language to deaf individuals from their deaf parents and deaf maternal grandparents. A new method is introduced to deal with the problem of grandparental transmission in which the basic variables are the frequencies of triplets comprising a mother, a father, and their daughter of permissible phenogenotypes. Usual stability analysis is then done on the system of linear recursions in the frequencies of these triplets, derived on the assumption that signers (users of the sign language) are rare. It is shown that assortative mating is the most important factor contributing to persistence, but that grandparental transmission can also have a significant effect when assortment is as strong as observed in England and the United States.

Deafness↗
PubMed1992

Selective reactivities of isocyanates towards DNA bases and genotoxicity of methylcarbamoylation of DNA.

The reactivities of methyl isocyanate (MIC) and phenyl isocyanate (PIC) with DNA, and the genotoxicity of MIC were investigated. MIC and PIC reacted with the exocyclic amino group of deoxycytidine, deoxyadenosine and deoxyguanosine to produce carbamoylated products. The reactions of both isocyanates with deoxycytidine were 2 and 4 orders of magnitude higher than with deoxyadenosine and deoxyguanosine, respectively. To explore the genotoxicity of MIC, M13mp9 RF DNA was modified with MIC and then introduced into E. coli. The plaque-forming efficiencies of DNA decreased with increasing dose levels, and the decreases were more pronounced in Uvr endonuclease-deficient strains (uvrA, uvrB and uvrC) than in the Uvr endonuclease-proficient strain, JM103. The differences in survival in JM103 and uvr- strains suggest that the methylcarbonyl adducts can be removed by the uvr excision-repair system. Modification of M13mp9 RF DNA with MIC induced MIC-dose-related, SOS-dependent mutations in the beta-galactosidase locus. These results demonstrate the genotoxic response of MIC-modified DNA in E. coli.

Carbamates↗
PubMed1992

Differential scanning calorimetric studies on bovine serum albumin: III. Effect of sodium dodecyl sulphate.

Measurements of differential scanning calorimetry (d.s.c.) have been made on the complex bovine serum albumin (BSA)--sodium dodecyl sulphate (SDS) under various conditions. There are two peaks P1 and P2 in the d.s.c. curve for BSA at pH 7 and in the absence of NaCl, indicating the presence of the heat-induced transition of BSA. There are three peaks P1, P2 and P3 in the curve for the system with the molar mixing ratio SDS/BSA = 1. With the increase in the amount of SDS, the peak P3 grows at the expense of P1 and P2. There is only a single peak P3 in the curve for the systems SDS/BSA > 7, and no peak at SDS/BSA = 50 and 100. There is a single peak P12 in the curve for BSA at pH 7 and in the presence of 0.05 M NaCl, indicating that the heat-induced transition is suppressed. There are two peaks P12 and P3 for the systems SDS/BSA = 1-5; the area ratio of the peak P3 to P12 increases with the increase in the amount of SDS. There is only a single peak P3 when SDS/BSA > 7, and no peak at SDS/BSA = 50. It is concluded that the peak P3 is a product of SDS regardless of the presence or absence of NaCl. Values of thermal denaturation temperature (Td) and enthalpy (delta H) of thermal denaturation indicate that the complex AD12 (A = BSA, D = SDS) is in the most thermostabilized state.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Effects of voluntary exercise on bone growth and calcium metabolism in spontaneously hypertensive rats.

The effects of voluntary exercise on bone length and calcium metabolism were investigated in spontaneously hypertensive rats (SHR) and Wistar rats. They were classified into voluntary exercise or sedentary group. Systolic blood pressure (SBP), bone length, urinary calcium excretion, plasma calcium and parathyroid hormone levels (PTH) were measured for analysis. SBP of the trained SHR (T-SHR) was significantly lower than that of the nontrained SHR (NT-SHR) at 10 and 11 weeks of age, but the trained Wistar rats (T-WR) and the nontrained Wistar rats (NT-WR) had similar SBP throughout the experimental period. The T-SHR had significantly longer bones in the extremities and the trunk than the NT-SHR, whereas the T-WR had similar or shorter bones than the NT-WR. The PTH level at 12 weeks of age was significantly lower in the T-SHR than in the NT-SHR. The urinary calcium excretion of the T-SHR was greater than that of the NT-SHR, but the food intake (calcium intake) of the T-SHR was also greater. The urinary calcium excretion and food intake of the T-WR and NT-WR were similar. No noticeable differences were observed in the plasma calcium level between the T-SHR and NT-SHR, the T-WR and NT-WR. From these results it is suggested that the abnormal calcium metabolism in the SHR is improved in some degree by voluntary exercise.

Animals↗
PubMed1992

No inhibitory effect of increased serum magnesium upon pressor response to infused calcium.

OBJECTIVE: The purpose of this study was to determine whether the pressor effect of infused calcium is inhibited by increased serum magnesium. DESIGN: Intravenous infusions of calcium, magnesium, and calcium+magnesium were performed in 10 subjects and the effect upon haemodynamic variables was investigated. METHODS: Intra-arterial blood pressure and heart rate were recorded during i.v. infusions of magnesium, calcium and calcium+magnesium. Cardiac output and serum concentration of electrolytes were measured before and after the infusions. Total peripheral vascular resistance (TPVR) was calculated from: mean blood pressure/cardiac output. RESULTS: Magnesium infusion increased serum magnesium, but did not change blood pressure, cardiac output or TPVR. Calcium infusion increased serum calcium and elevated both blood pressure and TPVR with no change in cardiac output. Calcium+magnesium infusion increased both serum magnesium and calcium, showing elevation of blood pressure and TPVR with no change in cardiac output. Changes in haemodynamic variables caused by the calcium+magnesium infusion were similar to those caused by the calcium infusion alone. CONCLUSIONS: These results suggest that increased serum calcium elevates blood pressure and TPVR through arterial vasoconstriction by arterial smooth muscle contraction, but increased serum magnesium does not induce arterial vasodilation.

Aged↗
PubMed1992

Differences in responses to TC-81 among various arteries in dogs.

The vasodilation induced by TC-81 was investigated in vitro and in vivo. In helical strips of dog arteries precontracted with 65.4 mM KCl, TC-81, nicardipine, nifedipine, diltiazem, and papaverine produced concentration-dependent relaxation. The potencies of TC-81 were in the following order: basilar > coronary > femoral > renal > mesenteric arteries. The other drugs also showed a similar property of greater response in basilar and coronary arteries than in renal and mesenteric arteries. However, the difference in reactivity to TC-81 was greater. On the other hand, TC-81, nicardipine, and papaverine dose-dependently increased the blood flow in vertebral, coronary, and femoral arteries in anesthetized dogs. However, the blood flow in renal and mesenteric arteries was not changed or decreased. The decreases in vessel resistance induced by TC-81 were in the following order: vertebral > coronary > femoral > renal = mesenteric arteries, agreeing with the experimental results in vitro. These results suggest that Ca2+ antagonists have the pharmacological property of vasodilating cerebral and heart blood vessels more selectively than other arteries, and this property of TC-81 might be an advantage compared with other drugs.

Animals↗