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Biomedical subjects

A Tani

Publications and source records attributed to A Tani.

At least 73 records · Page 4Linked to original sources
PubMed1997

Reversal of heavy metal resistance in multidrug-resistant human KB carcinoma cells.

Human KB carcinoma C-A120 cells that express multidrug resistance-associated protein (MRP) were cross-resistant to trivalent and pentavalent antimonials and arsenicals. Intracellular glutathione (GSH) content was higher in C-A120 than its parental KB-3-1 cell line. Glutathione-S-transferase (GST) was similar in both cell lines. Depletion of cellular GSH by treatment of the cells with the inhibitor of gamma-glutamylcysteine synthetase (gamma-GCS), buthione sulfoximine (BSO), significantly increased the sensitivity of both KB-3-1 and C-A120 cells to heavy metals. A pyridine analog, PAK-104P, almost completely reversed the resistance to antimonials and arsenicals in C-A120 cells. BSO at 100 microM or PAK-104P at 10 microM enhanced the accumulation of antimony potassium tartrate in C-A120 cells to the level of that in KB-3-1 cells without the agents. PAK-104P inhibited the ATP-dependent efflux of antimony potassium tartrate. These findings suggest that MRP transports antimony conjugated with GSH ATP-dependently outside the cells and PAK-104P inhibits the transporting activity of MRP.

ATP-Binding Cassette Transporters↗
PubMed1997

Function of P-glycoprotein expressed in placenta and mole.

We examined the expression of P-glycoprotein in human placentas and hydatidiform moles. Trophoblasts in all the examined placentas and moles expressed P-glycoprotein, and the size of the P-glycoprotein was smaller than that in multidrug-resistant human epidermoid carcinoma KB cells. The P-glycoprotein in the placenta and mole was photolabeled with [3H]azidopine, and [3H]vincristine was transported in an ATP-dependent manner into membrane vesicles prepared from trophoblasts that expressed P-glycoprotein. These findings indicate that P-glycoprotein expressed in trophoblasts has a drug binding site(s) and the ability to transport vincristine, suggesting that P-glycoprotein in the placenta protects the fetus from xenobiotics and confers drug resistance on moles.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1997

Numerous sites of increased uptake shown on bone scintigraphy in a case of adult T-cell leukemia.

Bone scintigraphy was performed in a 69-year-old male patient with adult T-cell leukemia suffering from right lower limb pain. Numerous sites of increased uptake were seen in the skull, left clavicle, bilateral humeri, bilateral radii and right femur and tibia. Bone radiographs showed multiple osteolytic lesions, most of which corresponded to the abnormal deposits on the bone scans with 740 MBq of 99mTc-hydroxymethylene diphosphonate. This pattern is rarely reported, but bone involvement of adult T-cell leukemia is not uncommon. Bone involvement was remarkable on the appendicular skeleton when compared with common metastatic bone tumors. Bone scintigraphy may be useful in detecting bone involvement in adult T-cell leukemia.

Aged↗
PubMed1997

I-123 iomazenil SPECT in patients with mental disorders.

The purpose of this study is visual evaluation of the distribution of I-123 iomazenil in the brains of patients with various types of mental disorder and to examine whether chronic administration of a clinical dose of benzodiazepine (BZ) affects the binding of I-123 iomazenil to BZ receptors (BZR). The subjects were 10 patients with mental disorders (3 males and 7 females) with a mean age of 26.8 yrs (range 19-39 yrs). Four of 10 patients were administered BZ for over 3 months and the other six were free of BZ for over one month. The SPECT images were obtained at 5-25 min (early) and 170-190 min (delayed), after the bolus i.v. injection of 167 MBq of I-123 iomazenil, with a triple-head gamma camera. The images were visually evaluated and the washout ratios of each region were calculated. In visual analysis, abnormalities were recognized in 5 patients on the delaye SPECT. The abnormalities were recognized more frequently in the superior frontal lobe. The washout ratio was higher in the BZ (+) patient group than in the BZ (-) patient group. I-123 iomazenil is useful, because the SPECT image with I-123 iomazenil reflects the distribution of BZR on the brain and provides the different information from that obtained with perfusion SPECT, X-ray CT or MRI. The rapid washout of I-123 iomazenil from the brains of BZ (+) patients suggests that chronic administration of a clinical dose of BZ affects the binding of I-123 iomazenil to BZR.

Adult↗
PubMed1997

Insulin-like growth factor-I stimulates in vitro migration of preosteoclasts across bone endothelial cells.

Little is known about the factors and the mechanisms involved in preosteoclast emigration from the vasculature. In this study, an in vitro model of bone endothelial lining was mimicked by culturing bone endothelial (BBE) cells at confluence on a 3-microm pore polycarbonate membranes. Preosteoclastic (FLG 29.1) cells were then added on top of the BBE cell monolayer and 10 nM insulin-like growth factor-1 (IGF-I) was added below the supporting membrane. Scanning and transmission electron microscopy were used to evaluate the chemotactic responses of preosteoclastic FLG 29.1 cells towards the IGF-I generated gradient. IGF-I potently stimulated chemotaxis in the FLG 29.1 cells, as shown by the migration of the preosteoclastic cells across the underlying BBE and through the intercellular junctions between adjacent endothelial cells. Subsequently, FLG 29.1 cells penetrated the pores of the supporting membrane and reached the lower face of the membrane. Thus, IGF-I, which is abundantly present in the bone tissue microenvironment, may play a paracrine role in the recruitment of the circulating preosteoclasts from the vascular compartment into the bone tissue. This in vitro model, which mimicks the in vivo phenomenon of preosteoclast extravasation, should prove useful in elucidating the molecular mechanisms that underlie this process.

Adult↗
PubMed1997

Effect of wind velocity on ethylene release from lettuce plants.

Effect of wind velocity on ethylene release rate of intact lettuce plant was investigated. Lettuce plants were grown at wind velocities of 0.1, 0.4, 0.8, and 1.4 m s-1 for 25 to 33 days and then used for ethylene measurement. When ethylene release rate of the plants grown at a wind velocity of 0.1m s-1 was measured at wind velocities of 0.2, 0.6 and 1.0m s-1 the rate was not affected by wind velocity. This result indicates that ethylene diffusion from lettuce leaf to atmosphere is not affected by boundary layer conditions. When ethylene release rate of the plants grown at wind velocities of 0.1, 0.4, 0.8 and 1.4 m s-1 was measured at the same wind velocity as growing conditions, the rate was scarcely increased by high velocity of wind. A strong wind (4.0 m s-1), which induced wounding damage in small areas of the leaves, had no measurable effect on a ethylene release of the whole plant.

Cell Membrane Permeability↗
PubMed1997

Lys-49-phospholipases A2 as active enzyme for beta-arachidonoyl phospholipid bilayer membranes.

Phospholipases A2 containing Lys-49 have been reported to be extremely weak or inactive as enzyme. We have recently shown that basic proteins I and II (BP-I and BP-II), Lys-49-PLA2s isolated from the venom of Trimeresurus flavoviridis (Habu snake), are potent to hydrolyze the arachidonate of 2-arachidonoyl-1-stearoyl-L-3-phosphatidylcholine (ASPC) in bilayer vesicles. In order to ensure such enzymatic activity of Lys-49-PLA2s, two other Lys-49-PLA2s from different snake venoms, myotoxin II (from Bothrops asper) and App-K49 (form Agkistrodon piscivorus piscivorus), were examined. Myotoxin II was found to be very active, even more potent than BP-II, liberating about 80% of arachidonic acid from liposomes. App-K49 was also active (about 50%) for ASPC liposomes. They were very weak or almost inactive for ASPC micelles and monomers. All these Lys-49-PLA2s were inactive for ASPC liposomes in the absence of Ca2+. These results clearly demonstrated that Lys-49-PLA2s are the enzymes to hydrolyze the C2-ester bond of ASPC in bilayer membranes.

Amino Acid Sequence↗
PubMed1997

Enterocytozoon bieneusi in AIDS: symptomatic relief and parasite changes after furazolidone.

AIMS: To investigate changes in morphology of the developmental stages of Enterocytozoon bieneusi and symptomatic relief observed in AIDS patients after treatment with furazolidone. METHODS: Six AIDS patients with symptomatic E bieneusi infection of the small intestine were treated with a course of furazolidone. All patients had a weekly monitoring of parasite shedding in stool by light microscopy during and after treatment. At the end of the treatment, duodenal biopsy specimens obtained from three patients were studied by transmission electron microscopy by two pathologists who were unaware of the patients' treatment. RESULTS: All patients showed both clinical and parasitological response with transient clearance or decrease of spore shedding in stool. After treatment, alterations in faecal spores were observed in all patients by light microscopy, and ultrastructural changes in E bieneusi at all stages of the life cycle were demonstrated in biopsy specimens of the three patients who underwent post-treatment endoscopy. CONCLUSIONS: The clinical benefit seen after treatment with furazolidone in six AIDS patients with E bieneusi intestinal infection may be due to damage to the developmental stages causing a partial inhibition to reproduction of the parasite.

AIDS-Related Opportunistic Infections↗
PubMed1997

Myocardial iodine-123-metaiodobenzylguanidine images and autonomic nerve activity in normal subjects.

UNLABELLED: We studied the relationship between myocardial [123I]metaiodobenzylguanidine (MIBG) uptake and autonomic nerve activity in normal subjects. METHODS: MIBG scintigraphy and power spectral analysis (PSA) of heart rate variability were performed simultaneously in 15 normal subjects. Anterior planar images and SPECT images were taken at five and two points after the injection of [123I]MIBG, respectively. In 10 of 15 subjects, 201TI myocardial SPECT was performed immediately after MIBG scintigraphy. RESULTS: The heart/upper mediastinum MIBG uptake ratio in the planar image obtained at 240 min (r = 0.64, p < 0.01) and the washout rate of MIBG in the heart between 15 min and 240 min (r = 0.51, p < 0.05) showed significant correlation with the percentage of low frequency component of PSA (percent LF), an index of sympathetic nerve activity. Regional MIBG uptake in the inferior wall normalized by individual maximal uptake among all pixels was significantly correlated with the high frequency component of PSA, an index of parasympathetic nerve activity (r = -0.58, p < 0.05) and with mean R-R interval in a resting ECG (r = -0.82, p < 0.001) but did not correlate with percent LF, percent uptake of 201TI in the inferior wall or the liver/heart uptake ratio. CONCLUSION: These results indicate that myocardial MIBG uptake correlates with sympathetic nerve activity in normal subjects. Our data indicate that heterogeneous MIBG distribution in the left ventricle is a physiologic rather than artifactual phenomenon and may be related to vagal tone rather than sympathetic nerve activity.

3-Iodobenzylguanidine↗
PubMed1997

Reversal of multidrug resistance-associated protein-mediated drug resistance by the pyridine analog PAK-104P.

Three agents, verapamil, cepharanthine, and 2-[4-(diphenylmethyl)-1-piperazinyl]ethyl-5-(trans-4,6-dimethyl-1, 3,2-dioxaphosphorinan-2-yl)-2,6-dimethyl-4-(3-nitrophenyl)-3-py ridinecarboxylate P-oxide (PAK-104P), that reverse drug resistance in P-glycoprotein (P-Gp)-mediated multidrug-resistant cells were examined for their activity to reverse drug resistance in multidrug resistance-associated protein (MRP)-mediated multidrug-resistant C-A120 cells. Agents other than PAK-104P could not reverse the resistance to doxorubicin in C-A120 cells. PAK-104P moderately reversed the doxorubicin resistance. In contrast, PAK-104P almost completely reversed the resistance to vincristine (VCR) in C-A120 cells as well as in KB-8-5 cells, and other agents moderately reversed the VCR resistance in C-A120 cells. PAK-104P at 10 microM enhanced the accumulation of VCR in C-A120 cells to the level of that in KB-3-1 cells without the agent. PAK-104P competitively inhibited the ATP-dependent [3H]leukotriene C4 uptake in membrane vesicles isolated from C-A120 cells. These findings demonstrate that PAK-104P can completely reverse the resistance to VCR in both P-Gp- and MRP-mediated multidrug-resistant cells and that PAK-104P directly interacts with MRP and inhibits the transporting activity of MRP.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1997

Vitamin E prevents neutrophil accumulation and attenuates tissue damage in ischemic-reperfused human skeletal muscle.

Neutrophil accumulation and the consequent production of oxygen-derived free radicals are involved in the pathogenesis of Ischemia-Reperfusion syndrome. In this study we investigated whether a treatment with Vitamin E, which has antioxidant properties, could attenuate the tissue damage by interfering with the influx of neutrophils within the ischemic and reperfused human skeletal muscle. To this purpose, patients undergoing aortic cross-clamping during the surgical repair of aortic abdominal aneurysm were studied as a model of ischemia-reperfusion of the lower limb muscles. Muscle biopsies from the right femoral quadriceps of patients not receiving and receiving Vitamin E pretreatment before surgery were taken: a) after the induction of anaesthesia, as control samples, and b) after a period of ischemia followed by 30 min of reperfusion. The tissue samples were either routinely processed for morphological study and immunohistochemical analysis to detect an altered expression of specific endothelial adhesion proteins, such as E-selectin and ICAM-1. The results obtained showed that Vitamin E administration was able to prevent the accumulation of neutrophils within the ischemic and reperfused muscle. This beneficial effect of Vitamin E was due to its ability to hinder the expression of E-selectin and ICAM-1, molecules known to increase the adhesiveness of endothelium to circulating neutrophils. After treatment with Vitamin E a marked attenuation of the reperfusion injury was also evident. In conclusion, Vitamin E treatment may be considered a valuable tool for protection against the ischemia-reperfusion damage of human skeletal muscle.

Aged↗
PubMed1996

Measurements of trace contaminants in closed-type plant cultivation chambers.

Trace contaminants generated in closed facilities can cause abnormal plant growth. We present measurement data of trace contaminants released from soils, plants, and construction materials. We mainly used two closed chambers, a Closed-type Plant and Mushroom Cultivation Chamber (PMCC) and Closed-type Plant Cultivation Equipment (CPCE). Although trace gas budgets from soils obtained in this experiment are only one example, the results indicate that the budgets of trace gases, as well as CO2 and O2, change greatly with the degree of soil maturation and are dependent on the kind of substances in the soil. Both in the PMCC and in the CPCE, trace gases such as dioctyl phthalate (DOP), dibutyl phthalate (DBP), toluene and xylene were detected. These gases seemed to be released from various materials used in the construction of these chambers. The degree of increase in these trace gas levels was dependent on the relationship between chamber capacity and plant quantity. Results of trace gas measurement in the PMCC, in which lettuce and shiitake mushroom were cultivated, showed that ethylene was released both from lettuce and from the mushroom culture bed. The release rates were about 90 ng bed-1 h-1 for the shiitake mushroom culture bed (volume is 1700 cm3) and 4.1 approximately 17.3 ng dm-2 h-1 (leaf area basis) for lettuce. Higher ethylene release rates per plant and per unit leaf area were observed in mature plants than in young plants.

Air↗
PubMed1996

Performance of a centrifugal phytotron.

It is possible to cultivate plants under an artificial gravity field generated by a centrifugal device in space. In order to determine an optimal magnitude of gravity, there is a need to investigate the relationship between plant and growth and gravity, including not only reduced gravity but also gravity greater than 1G. A prototype centrifugal phytotron was designed and fabricated in order to investigate the relationship between plant growth and increased gravity. This device enables us to cultivate plants over the long term by controlling environmental conditions in the phytotron such as temperature, relative humidity, CO2 concentration and light intensity. The results of our experiment indicate that plant seeds can germinate and grow even under an artificial gravity which changes sinusoidally from 2G to 4G.

Acceleration↗
PubMed1996

Diurnal heart rate variability in healthy subjects: effects of aging and sex difference.

To study the effects of aging and gender, circadian profiles of heart rate variability were evaluated for 105 healthy volunteers by frequency domain analysis of a Holter electrocardiogram record. The low-frequency (LF) component representing cardiac beta-adrenergic function showed high values for the 0800-1200 period in male subjects and the 1200-2400 period in female subjects. The high-frequency (HF) component representing parasympathetic function showed a peak for the 0000-0600 period in both male and female subjects independent of age. Male subjects showed significantly higher %LF [LF/(LF + HF) x 100] than female subjects. LF showed consistently highly significant correlation with age. These basic findings can help elucidate the diurnal profile of cardiac nerve function and how it is affected by aging and sex difference.

Adult↗
PubMed1996

Rates of ethylene release, photosynthesis and transpiration of rice measured in closed-type chamber.

To obtain the basic data of gas exchange of rice (Oryza sativa L. cv. Nipponbare), rates of ethylene release, photosynthesis and transpiration of the rice plant were measured by using a closed-type chamber. Each rate increased until the heading stage and thereafter decreased. Ethylene release rate (E) gradually increased with day after seeding and rates of photosynthesis (P) and transpiration (T) did exponentially. At the heading stage, E, P and T were maximum and had values of about 2.0 mmol plant-1 h-1, 3.0 mmol plant-1 h-1 and 0.60 mol plant-1 h-1, respectively. E in the light period was 1.5-3 times as much as that in the dark period, whereas T in the light period was 5-6 times as much as that in the dark period. E of rice per plant was lower than those of lettuce and Brassica genera which were reported previously. Especially, the rate of rice was about one-tenth that of lettuce. However, when ethylene release rates were estimated on a growth area basis, the rate of rice was about half that of lettuce, and was more than those of Brassica genera.

Ecological Systems, Closed↗
PubMed1996

Development of centrifugal phytotron to study the gravity effect on vegetable plant growth.

The present Spacetron is used to cultivate plants over a long term by controlling environment condition. The cultivation drum was rotated in perpendicular direction creating fluctuation in gravity. Centrifugal force plus 1 G ground gravity, are distributed unevenly over the cultivation drum. This fluctuation effect on plant growth was not clear. In the modified Spacetron the cultivation drum rotates horizontally whereas the plant stage rotated in the perpendicular direction. To find the basic information for design of centrifugal phytotron the two axes Spacetron Junior (clinostat) was developed to formulate the micro and hypergravity environment. It would be used to study the effect on a plant growth process of different gravity conditions. In order to produce the different values of gravity, the clinostat's axis was rotated with a stepping motor at different angular velocity. The axis rotated at 5.2 revolutions per minute (rpm) to create a centrifugal force equivalent to 0.01 G and the plant stage was rotated at 5.2 rpm. The chlorophyll value is higher in the plants under microgravity condition of 0.01 G whereas the fresh weight and dry weight are higher in the plants under control condition of 1 G earth gravity. The result of this study showed that the plant growth was affected by microgravity along with other known factors such as vibration and unknown factors.

Biomass↗