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Biomedical subjects

A Tanaka

Publications and source records attributed to A Tanaka.

At least 55 records · Page 3Linked to original sources
PubMed2004

Chronic inhalation toxicity and carcinogenicity study on potassium octatitanate fibers (TISMO) in rats.

A chronic inhalation toxicity/carcinogenicity study of potassium octatitanate fibers (TISMO) was conducted in male Fischer 344 rats. Groups of 135 rats were exposed via whole-body inhalation to 0, 20, 60, or 200 WHO fibers/cc of TISMO, 6 h/day, 5 days/w for 24 mo. Six of 30 subgroup rats were killed after 3, 6, 12, 18, and 24 mo of exposure for lung burden evaluations. Another 30 subgroup rats were removed from the exposure chambers after 6 mo of exposure, placed in clean air, and from this group 6 rats were killed at 3, 6, 9, 12, and 18 mo later to study lung clearance. The remaining 75 rats in each group were subjected to 24 mo of exposure for chronic toxicity and carcinogenicity study. Rats exposed to HEPA-filtered air (chamber control) were used as a negative control in each study. The lung burden results indicated that a time point of equilibrium between lung burden and lung clearance at 20 WHO fibers/cc exposure was attained after approximately 18 mo of exposure. There was no difference in the number of WHO fiber from the lungs between 18 and 24 mo at 20 WHO fibers/cc exposure. But disproportional rapid increase in lung burden at 200 WHO fibers/cc exposure appeared to be saturation of lung clearance mechanism resulting from lung overloading. At 200 WHO fibers/cc exposure, approximately 22.9 and 70.5 million WHO fibers were retained in the lung after 3 and 6 mo of exposure, respectively, but lungs revealed normal in appearance. However, alveolar walls enclosing aggregated TISMO-laden alveolar macrophages (AMs) showed fibrotic thickening and approximately 197.3 million WHO fibers were retained in the lungs after 18 mo of exposure. Inhaled fibers were rapidly cleared during 3- and 6-mo recovery periods, and thereafter gradually progressive fiber reduction was observed throughout 18 mo of recovery. The number of WHO fibers decreased by approximately 72%, 74%, and 79% in the 200, 60, and 20 WHO fibers/cc groups, respectively, at the end of the 18-mo recovery period following 6 mo of exposure. Although inhaled TISMO fibers in the 20 WHO fibers/cc exposure group were phagocytized by alveolar macrophages (AMs) the lung morphology appeared normal throughout 24 mo of exposure. At 60 WHO fibers/cc exposure, a slight dose- and time-dependent increase in TISMO-laden AMs was observed throughout 3, 6, and 12 mo of exposure and some alveoli containing aggregated TISMO-laden AMs showed alveolar wall thickening at 18 mo of exposure and minimal alveolar fibrosis at 24 mo of exposure. The exposure concentration is interpreted as a borderline effect level. At 200 WHO fibers/cc exposure, lungs preserved normal architecture at 3 and 6 mo of exposure. Some alveolar walls enclosing aggregates of TISMO-laden AMs were slightly thickened after 12 mo of exposure and revealed slight alveolar fibrosis after 18 and 24 mo of exposure. Neither exposure related-pulmonary neoplasm nor mesothelioma was observed in 24 mo of exposure. The 20 WHO fibers/cc exposure concentration is considered to be a no-observable-adverse-effect level (NOAEL). TISMO exposure limits of 1 WHO fiber/cc would not impose a significant health hazard to humans in the workplace based on the animal experiments and medical surveys on workers.

Administration, Inhalation↗
PubMed2004

Clinical comparison of the scanning CO2 laser and conventional surgery in the treatment of ingrown nail deformities.

AIM: To compare statistically the clinical effects and postoperative course of the scanning CO(2) laser and conventional surgical method to evaluate the clinical effectiveness of the former for the treatment of ingrown nail deformities. METHODS: We performed vaporization of the nail matrix using the scanning CO(2) laser in 25 cases with ingrown nail deformities. RESULTS: In 21 cases, the recurrence of ingrown nail deformity was not observed during follow-up. All cases were free of postoperative infection. Use of the scanning CO(2) laser reduced postoperative pain, and all patients were able to return to their daily activities by day 3 post-surgery without any problems. CONCLUSIONS: Statistically, the operating time and the duration of postoperative pain were reduced significantly by the scanning CO(2) laser. Furthermore, patients treated with CO(2) laser were able to return to daily life significantly sooner.

Adult↗
PubMed2004

Mechanisms underlying the gastroprotective action of glucocorticoids released in response to ulcerogenic stress factors.

Our previous results demonstrate the gastroprotective but not ulcerogenic action of glucocorticoids released in response to ulcerogenic stress factors. The present study was undertaken to investigate the possible mechanisms underlying the gastroprotective action of glucocorticoids in rat stomachs. The effects of deficiency of glucocorticoid production, with or without corticosterone supplementation, on blood flow velocity in gastric microvessels, microvascular permeability, mucus production, motility as well as gastric lesions were studied 3 to 4 h after the onset of ulcerogenic stimuli: water-restraint stress or indomethacin administration. The contribution of glucocorticoids in the healing process of gastric injury was also evaluated. The deficiency in glucocorticoid production significantly potentiated the functional disorders induced by ulcerogenic stimuli, such as a decrease in blood flow velocity and mucus production and an increase in gastric motility and in microvascular permeability, which resulted in aggravation of the formation of gastric lesions as well as impairment of their healing. The changes observed were prevented by supplementation of corticosterone at a dose mimicking a stress-induced corticosterone rise. We conclude that a gastroprotective action of glucocorticoids may be provided by multiple actions, including maintenance of the gastric mucosal blood flow and mucus production, attenuation of the enhanced gastric motility and microvascular permeability as well as beneficial influences on healing processes.

Animals↗
PubMed2004

Pulmonary angiomyolipoma recurring 26 years after nephrectomy for angiomyolipoma: benign clinical course.

Angiomyolipoma (AML), a benign renal tumor, has various clinical forms, and the nature of AML is not sufficiently understood because of few reports of long-term observation. We report a 57-year-old female without tuberous sclerosis who developed multiple pulmonary AML 26 years after a right nephrectomy for renal AML. A computed tomogram demonstrated multifocal round lesions with lipid-like density throughout both lung fields. An open lung biopsy revealed a histological diagnosis of pulmonary AML. An abdominal computed tomogram was also compatible with splenic AML. She has been in good health for 12 years since the lung biopsy over the 38 years since the nephrectomy. This case suggests that multicentric AML can recur at distant organs even after long-term silence in a patient who has a past history of renal AML.

Angiomyolipoma↗
PubMed2004

Arsenic removal from groundwater by a newly developed adsorbent.

A novel adsorbent, which had been developed for phosphate adsorption, was adopted for arsenic removal from groundwater. Adsorption isotherm, pH dependence of the isotherm and adsorption rate were studied by batch method. Furthermore, by using a granular adsorbent of 1.8 mm diameter which is commercially available, lab-scale experiments of continuous adsorption treatment of actual groundwater containing arsenic at 50 mg m(-3) were conducted to examine the performance of the adsorbent. A large amount of arsenic, i.e., 10 g As kg(-1), was adsorbed at pH 7.0 and 10 mg As m(-3) in equilibrium concentration. It was only a 5% higher amount compared to conventional activated alumina. However, twice the bed volume, i.e., total volume of effluent divided by empty column volume, was achieved till breakthrough by using this novel adsorbent. This may be because the pH decrease, which enlarges apparent adsorption capacity of the adsorbent, is caused by a self-pH decrease function of the adsorbent. The self-pH decrease function must be delivered by dissociation of Al (III) aquoion. The proton release was clearly observed in batch experiments.

Adsorption↗
PubMed2003

Crossing the gap from p- to n-type doping: nature of the states near the chemical potential in La(2)-(x)Sr(x)CuO(4) and Nd(2-x)Ce(x)CuO(4-delta).

We report on an x-ray absorption and resonant photoemission study on single crystals of the high-T(c) cuprates La2-xSrxCuO4 and Nd(2-x)Ce(x)CuO(4-delta). Using an intrinsic energy reference, we find that the chemical potential of La2-xSrxCuO4 lies near the top of the La2CuO4 valence band whereas in Nd(2-x)Ce(x)CuO(4-delta) it is situated near the bottom of the Nd2CuO4 conduction band. The data clearly establish that the introduction of Ce in Nd2CuO4 results in electrons being doped into the CuO2 planes. We infer that the states closest to the chemical potential have a Cu 3d(10) singlet origin in Nd(2-x)Ce(x)CuO(4-delta) and a 3d(9)L singlet origin in La2-xSrxCuO4.

Journal Article↗
PubMed2003

Arsenic and heavy metal contamination of vegetables grown in Samta village, Bangladesh.

Drinking of arsenic (As) contaminated well water has become a serious threat to the health of many millions in Bangladesh. However, the implications of contamination of agricultural soils from long-term irrigation with As-contaminated groundwater for phyto-accumulation in food crops, and thence dietary exposure to As, and other metals, has not been assessed previously in Bangladesh. Various vegetables were sampled in Samta village in the Jessore district of Bangladesh, and screened for As, Cd, Pb, Cu and Zn by inductively coupled plasma emission spectrometry (ICP-AES) and inductively coupled plasma mass spectrometry (ICP-MS). These local food products are the basis of human nutrition in this region and of great relevance to human health. The results revealed that the individual vegetables containing the highest mean As concentrations microg x g(-1)) are snake gourd (0.489), ghotkol (0.446), taro (0.440), green papaya (0.389), elephant foot (0.338) and Bottle ground leaf (0.306), respectively. The As concentration in fleshy vegetable material is low. In general, the data show the potential for some vegetables to accumulate heavy metals with concentrations of Pb greater than Cd. Some vegetables such as bottle ground leaf, ghotkol, taro, eddoe and elephant foot had much higher concentrations of Pb. Other leafy and root vegetables, contained higher concentrations of Zn and Cu. Bioconcentration factors (BCF) values, based on dry weight, were below 1 for all metals. In most cases, BCF values decreased with increasing metal concentrations in the soil. From the heavily As-contaminated village in Samta, BCF values for As in ladies finger, potato, ash gourd, brinjal, green papaya, ghotkol and snake gourd were 0.001, 0.006, 0.006, 0.014, 0.030, 0.034 and 0.038, respectively. Considering the average daily intake of fresh vegetables per person per day is only 130 g, all the vegetables grown at Samta had Pb concentrations that would be a health hazard for human consumption. Although the total As in the vegetables was less than the recommended maximum intake of As, it still provides a significant additional source of As in the diet.

Arsenic↗
PubMed2003

Sexual modification of female spinach seeds (Spinacia oleracea L.) by irradiation with ion particles.

The female seeds of a spinach plant (Spinacia orelacea L.) were exposed to He (12.5 MeV/n) and C (18.3 MeV/n) ions in order to investigate the effects of ion particles on sex expression. He ions did not affect germination rates or flowering at doses up to 50 Gy. C ions did not affect germination rates or flowering at doses up to 15 Gy, but a dose of 25 Gy resulted in many plants with morphological aberrations. When unexposed female plants were grown without cross-fertilization for 10 weeks after sowing, 5.6-14.3% of the plants produced anthers from female flowers. These sex-modified plants could self-pollinate and form seeds, which expressed only female organs. Conversely, gynomonoecious plants were induced from these female seeds by exposure to He ions (5-50 Gy) and C ions (5-25 Gy) without any difference in the rates of flowered progeny. Moreover, andromonoecious plants were induced from female seeds by exposure to He ions at 50 Gy. These results suggest that the sex of a spinach plant is expressed as a flexible phenotype, converging from female to gyno- and andromonoecy after exposure to ion particles.

Carbon↗
PubMed2003

Structure-function study of the amino-terminal stretch of the catalase subunit molecule in oligomerization, heme binding, and activity expression.

Analysis of the protein structure of bovine liver catalase suggested that the N-terminal region containing two alpha-helices may function as a linker binding to another subunit. The number of amino-acid residues in catalase from the n-alkane-assimilating yeast Candida tropicalis (CTC) is the lowest of any eukaryotic catalase molecule hitherto investigated, and only one helix, corresponding to the helix alpha2 in bovine liver catalase, is estimated to be present in the same region. In the present study, N-terminal-deleted mutants of CTC were characterized to evaluate the role of the alpha-helix structure in the N-terminal region. CTCDelta1-4 and CTCDelta1-24, whose N-terminal regions were shortened by four and 24 amino-acid residues, respectively, showed an 80% decrease in specific activity compared to wild-type CTC in spite of containing the same amount of heme as in the wild-type. Polyacrylamide gel electrophoresis under nondenaturing conditions revealed that the mutants contained large amounts of oligomeric forms with molecular masses less than 220 kDa (tetramer assembly). Although the smaller oligomers were found to be bound with heme, only the tetramer exhibited catalase activity in activity staining on nondenaturing gel. CTCDelta1-49, a mutant with deletion of the N-terminal 49 amino-acid residues which contain the conserved helix alpha2, showed no catalase activity and no heme binding. However, the CD spectrum profiles of CTCDelta1-49, CTCDelta1-4, and CTCDelta1-24 indicated that these mutant subunits could attain secondary conformations similar to that of wild-type CTC, regardless of their binding with heme. From these results, it was concluded that the N-terminal stretch of catalase is significant for complete assembly into active tetramer and that the conserved helix alpha2, although it has little effect on the formation of the subunit secondary structure, is indispensable not only in assembling tetramer but also in binding heme.

Amino Acid Sequence↗
PubMed2003

The novel differentiation of human blood mononuclear cells into CD1a-negative dendritic cells is stimulated in the absence of exogenous cytokines by an extract prepared from pinecones.

The production of dendritic cells, both in-vivo and in-vitro, has become the intense focus of research activities. Common to many of these production protocols is the use of cytokines, typically granulocyte-monocyte colony stimulating factor and either interleukin 4 or tumor necrosis factor alpha or a combination of all three. Herein, we report our findings that a proprietary pinecone extract is capable of in a dose-dependent manner, and in the absence of exogenous cytokines, the rapid differentiation from peripheral blood mononuclear cells of mature CD1a-negative dendritic cells.

Animals↗
PubMed2003

Intravenous gene therapy for familial hypercholesterolemia using ligand-facilitated transfer of a liposome:LDL receptor gene complex.

Familial hypercholesterolemia (FH) is an autosomal dominant disorder because of a mutation in the low-density lipoprotein receptor (LDLR) gene. Although lowering plasma cholesterol decreases the risk of coronary artery disease, FH patients respond poorly to pharmacologic treatment. Transferrin-facilitated intravenous transfer of a cationic liposome rabbit LDLR cDNA complex alleviated hypercholesterolemia in Watanabe Heritable Hyperlipidemic Rabbits (WHHL), an animal model of FH. Intravenous treatment dose dependently decreased plasma total and LDL cholesterol levels, correlating with an increased level of LDLR mRNA transcripts in leukocytes. Transferrin-facilitated intravenous delivery of cationic liposome LDLR gene complexes could serve as an important adjunct therapy for the treatment of FH.

Animals↗
PubMed2003

Attenuation of ganglioside GM1 accumulation in the brain of GM1 gangliosidosis mice by neonatal intravenous gene transfer.

A single intravenous injection with 4 x 10(7) PFU of recombinant adenovirus encoding mouse beta-galactosidase cDNA to newborn mice provided widespread increases of beta-galactosidase activity, and attenuated the development of the disease including the brain at least for 60 days. The beta-galactosidase activity showed 2-4 times as high a normal activity in the liver and lung, and 50 times in the heart. In the brain, while the activity was only 10-20% of normal, the efficacy of the treatment was distinct. At the 30th day after the injection, significant attenuation of ganglioside GM1 accumulation in the cerebrum was shown in three out of seven mice. At the 60th day after the injection, the amount of ganglioside GM1 was above the normal range in all treated mice, which was speculated to be the result of reaccumulation. However, the values were still definitely lower in most of the treated mice than those in untreated mice. In the histopathological study, X-gal-positive cells, which showed the expression of exogenous beta-galactosidase gene, were observed in the brain. It is noteworthy that neonatal administration via blood vessels provided access to the central nervous system because of the incompletely formed blood-brain barrier.

Adenoviridae↗
PubMed2003

LET dependence of lethality of carbon ion irradiation to single tobacco cells.

PURPOSE: To determine the radiation sensitivity and relationship between linear energy transfer (LET) and relative biological effectiveness (RBE) in single plant cells irradiated with heavy ions. MATERIALS AND METHODS: Single cells were isolated from the tobacco BY-2 cell line and irradiated with carbon ions (78.6-309 keV microm(-1)) and gamma-rays (0.2 keV microm(-1)). Two weeks after irradiation, colonies with 16 cells or more derived from the irradiated cells were counted as survivors. The surviving fraction was fitted using the single-hit, multitarget theory. RESULTS: The doses needed to reduce the surviving fraction of the cells to 0.1 (D10) of gamma-rays and carbon ions were 47.2 and 10.5-12.6 Gy, respectively. The RBE based on the D10 peaked at an LET of 247 keV microm(-1). The inactivation cross-section of carbon ions reached a plateau of 11.3 microm2 at an LET of 247 keV microm(-1). CONCLUSIONS: The radiation sensitivity of single tobacco cells was much lower than that of mammalian cells, although the mean number of base pairs per chromosome in the two cell types was similar. The RBE peak based on the D10 of carbon ions in single tobacco cells occurred at a higher LET than it does in other organisms.

Carbon↗
PubMed2003

Increased endothelin: nitric oxide ratio is associated with erythropoietin-induced hypertension in hemodialysis patients.

Regular administration of recombinant human erythropoietin (rHuEPO) is frequently associated with a rise in arterial blood pressure in hemodialysis (HD) patients. The aim of this study was to examine the effects of rHuEPO on plasma endothelin (ET)-1 and nitric oxide products (NOx) concentration in HD patients. Fifteen patients on maintenance HD with hematocrit of less than 25% were included in the present study. All patients received 3,000 units of rHuEPO intravenously three times a week at the end of each HD session. Plasma levels of ET-1, NOx, thromboxane B2 (TXB2), prostacyclin (6-keto-PGF1alpha), and cyclic guanosine 3',5'-monophosphate (cGMP) were measured before, 2, and 4 weeks after rHuEPO treatment. Plasma concentrations of ET-1, TXB2, and 6-keto-PGF1alpha were measured by radioimmunoassay. Plasma NOx was measured by high-performance liquid chromatography. An rHuEPO-induced increase in mean arterial blood pressure of over 6 mmHg occurred in 7 patients (hypertensive group), whereas the elevation of mean arterial blood pressure was less than 5 mmHg in 8 patients (nonhypertensive group). Plasma ET-1 levels were elevated in all HD patients. Elevated plasma ET-1 levels remained unchanged after rHuEPO treatment in the hypertensive group, whereas the increase in plasma ET-1 levels was attenuated in the nonhypertensive group. Plasma NOx concentrations were also increased in all HD patients. This increase in plasma NOx levels was lessened in the hypertensive group after rHuEPO administration; however, plasma NOx levels remained increased in the nonhypertensive group. Changes in mean arterial blood pressure were significantly correlated with changes in plasma ET-1/NOx ratio. Plasma levels of TXB2, 6-keto-PGF1alpha, and cGMP were unchanged after rHuEPO administration in the hypertensive and nonhypertensive groups. These results suggest that an increase in ET-1/NOx ratio in blood, probably occurring in vascular endothelial cells, may be associated with rHuEPO-induced hypertension in HD patients.

6-Ketoprostaglandin F1 alpha↗
PubMed2003

Cough receptor sensitivity to capsaicin does not change after allergen bronchoprovocation in allergic asthma.

BACKGROUND: The relationship between cough receptor sensitivity and eosinophilic inflammation of the airway in patients with asthma remains unclear. METHODS: Eighteen patients with asthma sensitised to house dust mite (HDM) were enrolled in a randomised parallel group study. Patients with asthma whose main symptom was cough were not enrolled in the study. Half the patients were randomly assigned to inhale saline and the other half to inhale HDM allergen. Cough receptor sensitivity to capsaicin, airway responsiveness to histamine, and sputum eosinophils analysed with hypertonic saline inhalation were investigated before and 24 hours after saline or HDM allergen bronchoprovocation. RESULTS: Patients inhaling saline showed no significant changes in sputum eosinophils (from 7.87% (95% confidence interval (CI) 5.08 to 12.19) to 8.60% (95% CI 3.03 to 14.18); p=0.97), airway responsiveness to histamine (from 726.68 micro g/ml (95% CI 251.90 to 2096.36) to 773.01 micro g/ml (95% CI 251.36 to 2377.23); p=0.96), or capsaicin sensitivity (from 7.23 micro M (95% CI 2.45 to 21.31) to 7.24 micro M (95% CI 2.46 to 21.31); p=0.96). Early asthmatic response was induced in all patients, and late asthmatic response was observed in six of nine patients inhaling HDM allergen. Although there were significant increases in sputum eosinophils (from 9.83% (95% CI 6.78 to 14.27) to 21.00% (95% CI 13.85 to 28.15); p<0.01) and airway responsiveness to histamine (from 784.16 micro g/ml (95% CI 318.24 to 1932.24) to 377.81 micro g/ml (95% CI 118.43 to 1205.24); p<0.05) 24 hours after HDM allergen inhalation compared with baseline levels, capsaicin sensitivity did not change significantly (from 5.75 micro M (95% CI 1.91 to 17.30) to 6.20 micro M (95% CI 2.21 to 17.38); p=0.77). CONCLUSIONS: These findings suggest that cough receptor sensitivity to capsaicin is not associated with eosinophilic inflammation of the airway in patients with allergic asthma whose main symptoms are wheezing and dyspnoea but not cough.

Adult↗
PubMed2003

[Perioperative management of patient with pulmonary operation associated with interstitial pneumonia].

The prognosis of patients complicated with interstitial pneumonia (IP) who undergo pulmonary operations is very poor if acute exacerbation occurs after the operation. We have experienced 6 cases in which operations were performed on lungs complicated with IP The first patient died due to acute exacerbation, but the subsequent 5 patients had good postoperative courses due to 1) short-term administration of low-dose steroid before and after the operation, 2) avoidance of administration of high concentration of oxygen during and after the operation, and 3) administration of erythromycin before and after the operation, 4) N-acetylcysteine inhalation and administration of dl-alpha-tocopherylnicotinate before and after the operation. It is thought that careful management of such patients is needed to prevent acute exacerbation even after discharge from hospital.

Humans↗
PubMed2003

[Treatment of strategy for traumatic disruption of the thoracic aorta accompanied by multiple trauma].

Disruption of the thoracic aorta due to blunt chest trauma is often fatal and should generally be treated surgically as soon as possible. However, cases of disruption of the thoracic aorta due to blunt chest trauma are often complicated by damage to vital organs, making treatment difficult. Our policy is to treat other organs before treating the thoracic aorta in 1) cases in which fracture of the pelvic bone or bleeding from abdominal cavity organs is causing shock and 2) cases of severe cerebral contusion or intracranial hemorrhage that require emergency surgical treatment. The use of a stent for treatment of acute-stage cases should be considered prudently.

Accidents, Traffic↗