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Biomedical subjects

K Aoki

Publications and source records attributed to K Aoki.

At least 577 records · Page 32Linked to original sources
PubMed1990

[Liver metastases of mucinous colorectal carcinoma: clinico-radiological study of six cases].

Clinico-radiological study was attempted in 6 cases of liver metastases from mucinous colo-rectal carcinoma. On plain Computed Tomography (CT) scans (n = 6), tumors were demonstrated as a low density area in 83% and its margin was unclear and irregular in all cases. On enhanced CT scans (n = 6), marginal enhancement of the lesion was recognized in 50%, while neither internal enhancement nor peripheral low density area as commonly seen in metastatic adenocarcinoma was revealed. Ultrasonography (US) (n = 5) showed homogeneous echogenic mass in all lesions and angiography (n = 4) did hypovascular mass with displacement above. For differential diagnosis of mucinous carcinoma from adenocarcinoma metastasized from colo-rectal cancer, integrated diagnosis using CT and US is necessary.

Adenocarcinoma, Mucinous↗
PubMed1990

Serum concentrations of carotenoids, retinol, and alpha-tocopherol in healthy persons determined by high-performance liquid chromatography.

Serum concentrations of alpha-carotene (AC), beta-carotene (BC), lycopene (LY), beta-cryptoxanthin (CR), zeaxanthin (including lutein. ZX), canthaxanthin (CX), retinol (RE), and alpha-tocopherol (TO) in healthy persons (618 males and 1,196 females) aged 7-86 years were determined by HPLC. Serum concentrations of BC among persons aged 20-49 years were higher with increasing age in females, but not in males. Serum CR concentrations decreased with age ranging from 7 to 39 years, while ZX concentrations rose in the age group of 20 to 59 years for both sexes. In contrast, serum RE concentrations and ratios of RE/BC and RE/CR, especially in males aged 20-49, were higher with age. Serum TO values in both sexes rose with age and were similar.

Adolescent↗
PubMed1990

Effects of bepridil compared to those of its quaternary analogue on femoral arteries from spontaneously hypertensive rats.

The effects of bepridil and its quaternary analogue, methylated bepridil, were studied on femoral arterial strips from spontaneously hypertensive rats (SHR). Methylated bepridil relaxed precontracted strips more rapidly than did bepridil, but bepridil was a more potent vasorelaxant. Both drugs non-competitively inhibited arterial contraction evoked by voltage-dependent or alpha-adrenoceptor-operated Ca2+ influx with bepridil being more potent than methylated bepridil. In the absence of extracellular Ca2+, the contractile responses of Wistar-Kyoto rats (WKY) and SHR arteries to norepinephrine and caffeine were reduced similarly by methylated bepridil and bepridil. It is suggested that the effects of bepridil involve both extracellular and intracellular actions. The altered sensitivity of the contraction mechanism with norepinephrine-releasable Ca2+ to the Ca2+ antagonist may be due to an abnormality in the intracellular vasocontraction process distal to Ca2+ release from storage sites of the SHR blood vessels.

Animals↗
PubMed1990

Systemic chemotherapy in tumor-bearing rats using high-dose cis-diamminedichloroplatinum(II) with low nephrotoxicity in combination with angiotensin II and sodium thiosulfate.

Systemic chemotherapy using high-dose DDP and its antidote, STS, was combined with the AT-II-induced hypertension method and evaluated for efficacy against s.c. tumors in rats. After i.v. infusion of DDP plus AT-II for 5 min, STS was administered i.v. over a further 5 min. The rats treated with this combination chemotherapy showed normal levels of BUN and serum creatinine 4 days after the treatment, although most rats given i.v. STS after DDP without AT-II showed severe nephrotoxicity. The absence of obvious nephrotoxicity in AT-II-combined chemotherapy using i.v. DDP plus post-administered STS can be explained by a transient inhibition of DDP-delivery to the kidney during the AT-II-induced hypertension. The anti-tumor effect of this modified therapy, evaluated by inhibition of tumor growth, was superior to other treatments, as follows: concomitant i.v. administrations of DDP and STS; i.v. DDP, with or without AT-II. The improvement in anti-tumor effect of this combination therapy is explained by the delayed neutralization of active DDP by STS at the tumor site and the selective enhancement of DDP delivery to the tumor tissue, as produced by AT-II. Thus, systemic chemotherapy using high-dose DDP induced no obvious nephrotoxicity and improved the anti-cancer effect in the case of concomitant administration of DDP plus AT-II and the time-delayed injection of STS.

Angiotensin II↗
PubMed1990

Horseshoe lung without respiratory distress.

A case of horseshoe lung associated with scimitar syndrome is reported. The patient, a six year old boy, had no respiratory distress. Plain chest film showed hypoplasia of the right lung and scimitar vein. Angiography demonstrated that right inferior pulmonary arteries crossed the midline and reached to the left lung base.

Child↗
PubMed1990

New plastic-coated coaxial catheter system for superselective hepatic catheterization: technical note.

With the use of a new improved coaxial catheter system, superselective hepatic catheterization has become easier. The improvements consist of a decrease in the outer and an increase in the inner diameters of the coaxial catheters from 0.98 to 0.96 mm and from 0.55 to 0.65 mm, respectively, and thickening of core guidewire material from 0.014 inch (0.35 mm) to 0.018 inch (0.40 mm). With this new catheter system, it is possible to inject contrast medium (iopamidol 300) at a higher rate (3 ml/sec) and gelatin sponge particles instead of gelatin powder for arterial embolization. The success rates for superselective catheterization using conventional (n = 10 procedures) and the improved coaxial catheter systems (n = 7) were 30% and 86%, respectively.

Catheterization↗
PubMed1990

Increased therapeutic effect on metastatic liver tumors in rats of two-route chemotherapy using cis-diamminedichloroplatinum (II) and its antidote, sodium thiosulfate, with temporary clamping of the abdominal aorta.

To improve the therapeutic effects of conventional "two-route chemotherapy" (TRC) comprising cis-diamminedichloroplatinum(II) (CDDP) given via the hepatic artery plus simultaneous i.v. sodium thiosulfate (STS) on metastatic liver tumors in rats, we combined TRC with aortic clamping at the supraceliac level. Treatments were evaluated in Wistar-King-Aptekman (WKA) rats bearing metastatic liver tumors 7 days after the inoculation of 10(6) syngenic RBT-1 (transitional-cell carcinoma) cells via the mesenteric vein. When 15 mg/kg CDDP was injected i.a. over 5 min, immediately followed by STS 1,580 mg/kg (200-fold the molar equivalent of 15 mg/kg CDDP) given i.v. over a further 5 min, the antitumor activity, evaluated by the number of tumor nodules present 12 days after treatment, was superior to that of conventional TRC (15 mg/kg i.a. CDDP plus simultaneous administration of 1,580 mg/kg i.v. STS), but the blood urea nitrogen (BUN) level was highly elevated (63.6 mg/dl). With aortic clamping for 7.5 min during CDDP administration and the first half of STS treatment, the TRC consisting of CDDP plus delayed STS (modified TRC) exhibited a further improvement in antitumor activity, with no nephrotoxicity (BUN, 17.1 mg/dl). Although the antitumor activity of 3 or 5 mg/kg i.a. CDDP was also increased by aortic clamping, in animals with normal BUN levels the survival of those treated with modified TRC was greater than that of rodents given 3 mg/kg i.a. CDDP with aortic clamping; however, the former was the same as that of animals given 5 mg/kg i.a. CDDP with aortic clamping whose BUN levels were elevated (31.2 mg/dl). Loss of body weight, the decrease in WBC counts, and changes in the serum transaminase levels in rats given modified TRC were tolerable. The improved therapeutic effect of modified TRC can be explained as follows: during aortic clamping, (a) CDDP delivery to the kidney decreased by 96% and made feasible the delay in STS administration after CDDP without nephrotoxicity, and (b) CDDP retention in the liver was increased by 366%, as aortic clamping decreased the portal blood flow, thereby inhibiting the washout of CDDP from the liver.

Animals↗
PubMed1990

Influence of postural change on transmitral flow velocity profile assessed by pulsed Doppler echocardiography in normal individuals and in patients with myocardial infarction.

The influence of postural change from lying to sitting on transmitral flow velocity profile was investigated by pulsed Doppler echocardiography in eight normal individuals and in eight patients with myocardial infarction. The postural change decreased early and atrial filling velocities in the normal individuals (61 +/- 10 to 49 +/- 7 cm/sec and 66 +/- 8 to 55 +/- 7 cm/sec, p less than 0.01, respectively), and also decreased early filling but increased atrial filling velocity in the eight patients (62 +/- 13 to 43 +/- 12 cm/sec and 56 +/- 11 to 65 +/- 14 cm/sec, p less than 0.01 and p less than 0.05, respectively). These changes were associated with a reduction in pulmonary artery wedge pressure in the normal subjects and in the patients (5 +/- 2 to 2 +/- 2 mm Hg and 12 +/- 4 to 8 +/- 3 mm Hg, p less than 0.01, respectively). These observations indicate that a preload reduction alters the left ventricular diastolic filling profile. The differences in Doppler alterations between the groups may be attributed to the fundamental differences in intrinsic left ventricular diastolic properties of normal subjects and patients with myocardial infarction.

Aged↗
PubMed1990

Differential scanning calorimetric studies on bovine serum albumin: I. Effects of pH and ionic strength.

Using defatted and SH-blocked bovine serum albumin (BSA), the measurement of differential scanning calorimetry (d.s.c.) was performed in the range pH 3-11 and ionic strength 0.001-1 M. The shape of the d.s.c. curve was classified into four regimes: (i) the curve with no peak, (ii) that with a peak, (iii) that with a peak having a shoulder, and (iv) that with two peaks. The presence of two peaks was interpreted by the concept of 'heat-induced transition'. The BSA molecule is composed of two domains, thermodynamically independent owing to the formation of a crevice in BSA in a particular range of pH and ionic strength; this gives two peaks in the d.s.c. curve. The enthalpy (delta H) from the d.s.c. curve was plotted against pH and against the NaCl concentration. The value of delta H increased with the increase in the ionic strength in the pH range 5.6-9.0. The temperature of thermal denaturation (the temperature of the peak maximum, Td) was raised with the increase in the ionic strength in the pH range 4.5-9.0, but was lowered in the pH range 3.5-4.0. BSA was stabilized in the neutral-alkaline pH range by the presence of NaCl, but was destabilized in the acidic pH range.

Calorimetry, Differential Scanning↗
PubMed1990

Immunoassay for methamphetamine with a new antibody.

p- and o-Aminomethamphetamine were synthesized as haptens to be coupled with carrier protein at the benzene ring of methamphetamine. Immunogens were prepared by the glutaraldehyde method or the MBS (N-(m-maleimidobenzoyloxy)succinimide) type cross-linking reagent method. In particular, immunization with p-aminomethamphetamine-bovine serum albumin (BSA) conjugate prepared by the glutaraldehyde method gave an anti-methamphetamine antiserum having a low cross-reactivity with methylephedrine. With the antiserum, three kinds of immunoassays for methamphetamine were established. An enzyme immunoassay (EIA) and an enzyme-linked immunosorbent assay (ELISA) were developed with alkaline phosphatase (ALP) as a label enzyme. The amount of antibody bound ALP conjugate was determined by its activity in dephosphorylating p-nitrophenyl phosphate in EIA and nicotinamide adenine dinucleotide phosphate (NADP+) in ELISA. The range of methamphetamine measurable by ELISA was 0.025-0.5 ng/well and its sensitivity was superior to that of EIA (0.3-300 ng/tube). A latex agglutination inhibition reaction test (LAIRT) was also developed for the mass screening method of urine samples. The sensitivity of this method for methamphetamine was 0.1 micrograms/ml urine.

Alkaline Phosphatase↗
PubMed1990

Age at menarche and selected menstrual characteristics in young Japanese athletes.

Ages at menarche and selected menstrual characteristics in 204 nonathletes, 253 high school athletes, 386 college athletes, and 40 young top athletes of Japan were investigated by questionnaire. Data from the questionnaire have confirmed (a) the ascending trend of ages of menarche with advancement of training and competitive level, and (b) the diversity of mean age at menarche by sport in a given level. The menarcheal orders by sport in the literature have been found to be strikingly similar to those found in the present data. We offer the hypothesis that ages at menarche and selected menarcheal characteristics (a) are brought about by selection in the socialization process into sports participation, and (b) reflect the diversity of suitable physiques by sport. Also, the higher the training and competitive level, the more likely the occurrence of menstrual irregularity (cycle length and period duration) and/or dysmenorrhea (backache).

Adolescent↗
PubMed1990

A silicon diode in a thimble-type mount for measurement of diagnostic x-ray spectra.

A silicon detector which can be used like a thimble chamber has been constructed. The silicon diode chip used here is very small (1.7 x 1.7 x 0.1 mm3), and the construction materials of the detector mount are thin and have low atomic numbers. Thus, the characteristic x-rays from the mount give no distortion on the obtained spectra, and the photons incident on the back surface of the silicon chip can be measured. Furthermore, the perturbation of the x-ray field is small. The energy resolution of the detector is 2.0 keV (full width at half maximum) for 59.5 keV photons at room temperature. Bremsstrahlung spectra (60-100 kV, 1-2 mA) have been measured without using a pinhole collimator; the obtained spectra are in good agreement with those obtained with a Ge detector. The spectrum of the radiation in a water phantom irradiated with 90 kV x-rays has also been measured by inserting the detector in the phantom; the obtained scattered spectrum has been corrected for the angular dependence of detector efficiency. The increase in total photon number due to this correction has been found to be below 2%.

Biophysical Phenomena↗
PubMed1990

Characterization and genotoxicity of DNA adducts caused by 2-naphthyl isocyanate.

Calf thymus DNA and M13mp9 RF DNA were modified with [ring-3H]2-naphthyl isocyanate (NIC) and analyzed by reverse-phase HPLC following enzymatic hydrolysis. In each case, essentially, a single radioactive component, which co-chromatographed with authentic N4-2-naphthyl-carbamoyl-2'-deoxycytidine (NCdC), was detected. In order to explore the biological potential of this adduct, mp9 RF DNA modified with NIC was introduced into Escherichia coli strains using a calcium chloride technique. The plaque-forming efficiencies of DNA decreased with increasing adduct level, and the decreases were more pronounced in Uvr endonuclease-deficient strains (i.e. AB1886, uvrA; AB1885, uvrB; AB1884, uvrC) as compared to JM103 (Uvr endonuclease proficient) and JM101 RH03 (recA). These results suggest that these lesions, NCdC adducts, can be removed by the Uvr endonuclease repair system. Mutations were detected as the loss of ability of the bacteriophage to complement the defective beta-galactosidase of the host cells. Induction of SOS functions in the host cells enhanced the mutation frequency to 0.089%, i.e. greater than or equal to 4-fold greater than in non-SOS-induced cells, in transfections with RF DNA that contained 100 adducts/molecule. The mutagenic potency of this cytidine lesion is lower than that of the guanine-C8 adducts of 2-aminofluorene and 2-acetylaminofluorene as reported previously for this mutagenesis system.

Cyanates↗
PubMed1990

Correlation of increased serum calcium with elevated blood pressure and vascular resistance during calcium infusion in normotensive man.

The effects of intravenous calcium infusion on blood pressure (BP) and total peripheral vascular resistance (TPR) were investigated in seven normotensives at rates of 3.75, 7.5 and 15.0 mg/kg per h for 1 h. The infusions increased serum calcium levels, with significant elevations of BP and TPR, but had no effect on cardiac output, indicating that the TPR elevation induced the BP rise. The increase in serum calcium was correlated with elevations of systolic, diastolic and mean BP and TPR (r = 0.74, 0.78, 0.77 and 0.82, respectively; P less than 0.001); greater increases in serum calcium resulted in greater elevations of TPR and BP. The serum calcium increase was also associated with reductions in plasma parathyroid hormone and renin activity, and an increase in plasma aldosterone, which might have contributed to the rise in BP. Our results suggest that an increased serum calcium level led to calcium influx into arterial smooth muscle, which increases cytosolic calcium, induces muscle contraction, and thereby produces arterial vasoconstriction, leading to elevations of TPR and BP.

Blood Pressure↗
PubMed1990

Mechanism of Methane Transport from the Rhizosphere to the Atmosphere through Rice Plants.

To clarify the mechanisms of methane transport from the rhizosphere into the atmosphere through rice plants (Oryza sativa L.), the methane emission rate was measured from a shoot whose roots had been kept in a culture solution with a high methane concentration or exposed to methane gas in the gas phase by using a cylindrical chamber. No clear correlation was observed between change in the transpiration rate and that in the methane emission rate. Methane was mostly released from the culm, which is an aggregation of leaf sheaths, but not from the leaf blade. Micropores which are different from stomata were newly found at the abaxial epidermis of the leaf sheath by scanning electron microscopy. The measured methane emission rate was much higher than the calculated methane emission rate that would result from transpiration and the methane concentration in the culture solution. Rice roots could absorb methane gas in the gas phase without water uptake. These results suggest that methane dissolved in the soil water surrounding the roots diffuses into the cell-wall water of the root cells, gasifies in the root cortex, and then is mostly released through the micropores in the leaf sheaths.

Journal Article↗
PubMed1990

Changes in serum concentrations of beta-carotene and changes in the dietary intake frequency of green-yellow vegetables among healthy male inhabitants of Japan.

Serum levels of beta-carotene among 147 healthy male inhabitants were measured twice with an interval of one year in order to determine the relationship between changes in serum beta-carotene levels and changes in the dietary intake of green-yellow vegetables. A positive association was found to exist between changes in the intake frequency of green-yellow vegetables and changes in serum beta-carotene levels, whereas changes in alcohol intake and smoking were discovered to be negatively associated with changes in serum beta-carotene levels. The positive association between changes in the intake frequency of green-yellow vegetables and changes in serum beta-carotene levels was preserved after adjustment for these negative factors.

Adult↗
PubMed1990

[Study of serological diagnosis in ocular chlamydial infection with IPAZYME].

We employed a indirect immunoperoxidase assay (IPAZYME in the evaluation of IgG and IgA antibody for Chlamydia trachomatis in serum samples from 218 patients such as cicatricial trachoma 55 cases, culture-positive adult inclusion conjunctivitis 48 cases and culture-negative conjunctivitis 47 cases, aged people, 68 cases as controls respectively. Frequency of positive IgG antibody showed a significant difference between adult inclusion conjunctivitis or cicatricial trachoma and controls. IgA antibody was positive in 25/48 (52%) in adult inclusion conjunctivitis and in 7/55 (12%) in cicatricial trachoma cases. Serum IgA antibody against Chlamydia trachomatis is of value to be an index of active ocular chlamydial inflammation. The correlation between severity of conjunctival cicatrix or corneal punnus and titers of IgG antibody was also significant.

Aged↗