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Biomedical subjects

M Adachi

Publications and source records attributed to M Adachi.

At least 577 records · Page 32Linked to original sources

Synchronized discharge of taste neurons recorded simultaneously in rat parabrachial nucleus.

1. Cross-correlation analysis was made in the taste-sensitive neuron pairs recorded simultaneously from the parabrachial nucleus (PBN) of rats. Three indexes were adopted to evaluate the activities of the taste neurons; namely, 1) spike response density (RD value), which is the net spike density to stimulation with the four basic tastes; 2) the frequency of correlated discharges (FC value in spikes per second), which was determined by measuring the area of the peak appearing in the cross-correlogram (CC) during application of the test fluids; and 3) the weight of correlated discharge (WC = FC/RD), which shows the relative importance of correlated discharges in the taste signals delivered by a component neuron of a given pair. 2. In 11 of 23 pairs, the CCs exhibited peaks during stimulation with tastants. These 11 pairs, which were recorded in the pontine taste area, were composed of 18 NaCl-best (most sensitive to NaCl) and 4 HCl-best neurons. In eight pairs, the best-stimulus of both of the component neurons was NaCl, and it was HCl in one pair (homo-type pairs). The remaining two pairs were composed of an NaCl-best and an HCl-best neuron (hetero-type pairs). 3. In eight homo-type pairs (7 NaCl-best pairs and 1 HCl-best pair), each pair exhibited the maximal FC value during stimulation with the best-stimulus of the component neurons (2.3 less than or equal to maximal FC less than or equal to 26.6 Hz). In the remaining three pairs, the maximal FC values were low (0.8-1.9 Hz).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

Mechanism of clearance of circulating CA19-9 in rats.

Molecules bearing the carbohydrate antigen 19-9 (CA19-9) epitope were prepared from serum and ascites of a patient with colon cancer or from the SW 1116 cell culture supernatant. Their plasma clearance mechanism was investigated in rats. The clearance curves of the molecules from three different sources showed a biphasic decrease. The coexistence of epitopes of CA19-9 and desialylated CA19-9 (Lea) in the same molecule was demonstrated by double-determinant enzyme immunoassays. CA19-9-bearing molecules with a low expression of Lea epitope, which were derived from the serum of a patient with colon cancer, showed mainly a slow disappearance, while the molecules with a high expression of Lea epitope from SW 1116 cells showed mainly a rapid disappearance. Thus, the clearance rate of the CA19-9-bearing molecules might be determined by their degrees of sialylation. This observation will be helpful for understanding the in vivo metabolism of CA19-9-bearing molecules.

Animals↗

Oxide adherence and porcelain bonding to titanium and Ti-6Al-4V alloy.

The bonding of an experimental low-fusing porcelain to titanium and Ti-6Al-4V was evaluated by an x-ray spectrometric technique that measures the area that remains covered with porcelain following a controlled deformation of the metallic substrate. Oxide adherence strength values for titanium and Ti-6Al-4V oxidized at 750 degrees and 1000 degrees C were measured in tension with use of high-strength adhesives. The effect of further oxidation that would occur during porcelain firing was evaluated via simulated porcelain firings without actual porcelain application. Interface cross-sections of the titanium-porcelain and Ti-6Al-4V-porcelain bonds were examined in a scanning electron microscope (SEM). The porcelain was found to delaminate completely from the metal substrate, leaving less than 1% of the surface covered with porcelain. The oxide adherence of the specimens oxidized at 750 degrees C was good, but those oxidized at 1000 degrees C exhibited significantly lower oxide adherence (p = 0.001). The simulated porcelain-firing oxidation treatments also produced a significant decrease in oxide adherence (p = 0.004). The 750 degrees C oxidation treatments produced oxide films too thin to be visualized in the SEM, whereas the 1000 degrees C oxidation treatments produced oxide films approximately 1 micron thick. The lower oxide adherence of the 1-micron-thick oxide films is consistent with reports in the titanium literature of oxide delamination when the oxide film reaches 1 micron in thickness.

Alloys↗

[Effect of OKY-046 on airway hyperresponsiveness induced by ozone in dogs].

To elucidate the possible involvement of thromboxane A2 (TxA2) in airway hyperresponsiveness, we examined the effect of OKY-046, a potent and selective inhibitor of TxA2 synthetase, on airway hyperresponsiveness induced by ozone exposure in dogs. Ozone exposure (3 ppm, 2 hr) markedly increased airway responsiveness to inhaled methacholine without affecting basal respiratory resistance. Although ozone also caused a slight but significant increase in neutrophil number in the bronchoalveolar lavage fluid, there was no correlation between the level of airway hyperresponsiveness and increased neutrophil number. Although OKY-046 significantly inhibited the increases in airway hyperresponsiveness in a dose-dependent manner at doses ranging from 100 to 300 mg/kg, p.o., the compound did not affect the basal airway responsiveness and respiratory resistance at 300 mg/kg, p.o. Inhalation of the subthreshold concentration (i.e., the highest dose which did not cause bronchoconstriction) of STA2 (a stable TxA2 mimetic agent) elicited a significant increase in airway responsiveness to methacholine. These results suggest that TxA2 may play a role in mediating ozone-induced airway hyperresponsiveness. However, the accumulation of neutrophils in the airway lumen may not be essential for the development of airway hyperresponsiveness.

Acrylates↗

[Histologic characterization of late asthmatic response in guinea pigs].

We examined lung tissues in a guinea pig model actively sensitized by inhalation of aerosolized ovalbumin (OA) and found reproducible late bronchial responses (LBR) 7 h and 24 h after OA challenge. Light microscopic examination revealed bronchoconstriction, damage to the epithelium, eosinophil infiltration in both the epithelium and subepithelium, retention of mucous in the pulmonary bronchial lumens and a decrease in the mucous content of Periodic Acid-Schiff (PAS) stain positive cells in the bronchial epithelium in LBR. An increase in the number of PAS-stain positive cells of in the bronchial epithelium was also observed in LBR. Electron microscopic examination revealed eosinophil migration around mast cell at 7 hs after OA challenge. Two different mechanisms of degranulation of eosinophil specific granules were observed in LBR. In one mechanism, the granule core changes after its matrix has changed. In the other mechanism, the granules were exocytosed as a whole, accompanied by the cell membrane and densely clumped chromatin, suggesting burst of eosinophil.

Animals↗

Internal sclerostomy with argon contact laser--animal experiment using 5-fluorouracil.

A full-thickness sclerostomy was carried out with an ab interno approach, using an argon endolaser, in 9 eyes of 7 rhesus monkeys. After the injection of sodium hyaluronate into the subconjunctival space and the anterior chamber, a 300 micron fiber optic probe coupled with a water-cooled argon laser was inserted into the anterior chamber through the corneal incision made by a 23-gauge needle and positioned on the trabecular meshwork opposite to the corneal incision. A patent sclerostomy was obtained in all 9 eyes by 1 to 3 laser pulses with an energy of 4 W and a pulse duration of 0.5 seconds. After the surgery, 0.1 ml of 5-fluorouracil was injected subconjunctivally every day for one week. Intraocular pressure (IOP) was determined by pneumatic tonometer for one month at appropriate intervals. Mean preoperative IOP was 22 mmHg in both operated and nonoperated eyes. After one month IOP was 4.6 +/- 0.4 mmHg lower in the operated eyes than in the nonoperated eyes. Histologic study revealed that the sclerostomies from the anterior chamber opening to the subconjunctival space with the diameter of 200-300 microns still remained patent one month after surgery. Ab interno sclerostomy with an argon endolaser would be useful as a new filtering procedure which can easily be performed with minimum conjunctival damage.

Animals↗

[An advanced gastric carcinoma which responded to combined administration of mitomycin C, FT-207, and lentinan immunochemotherapy].

A 59-year-old man with a gastric cancer underwent a laparotomy and was found to have an unresectable tumor that formed a large mass with metastatic lymph nodes around the aorta. He therefore was treated by a combined administration of Mitomycin C, FT-207, and Lentinan for 3 months. Remarkable tumor reduction was observed endoscopically, and a subtotal gastrectomy was performed. The immunochemotherapy then was resumed, and the patient has survived for 16 months despite the remnant lymph node metastases. A histological examination of the resected stomach revealed a marked degeneration of the tumor.

Adenocarcinoma↗

Cytosolic calcium mobilization and thromboxane synthesis in a human megakaryocytic leukemia cell.

The functional and biochemical characteristics of human megakaryocytic leukemia cells remain unclear. In this study, we examined cytosolic Ca2+ ([Ca2+]i) mobilization and thromboxane (TX) formation in a megakaryocytic leukemia cell line, designated CMK. Stimulation of CMK cells with thrombin resulted in an increase of [Ca2+]i as measured with the fluorescent marker Fura 2-AM. The rise in [Ca2+]i was mostly dependent on extracellular Ca2+. Prostaglandin E1 (PGE1) further increased [Ca2+]i after thrombin addition, thus indicating that PGE1 had a different action on [Ca2+]i in cells of the platelet-megakaryocyte lineage. The addition of thrombin and the calcium ionophore A23178 to CMK cells caused similar rapid formations of TXB2 as measured by RIA. Thrombin plus A23178 had a synergistic effect on TXB2 synthesis in CMK cells. Thrombin had no effect of TX metabolism in the cells with myeloid, erythroid, B-lymphoid, and T-lymphoid lineages. These results indicate that thrombin-induced TX synthesis may serve as a marker of immature megakaryocytes.

Alprostadil↗

[Weibull statistical analysis of bending strength data measured either in air or in distilled water for sintered hydroxyapatite ceramics coated on the metal substrate].

To assess the effects of H2O on the fracture stress of sintered hydroxyapatite (HAP) ceramics prepared by procedures similar to those used for HAP coated on the metal substrate, four-point bending tests were carried out at 0.5 mm/min either in air (20 C, R.H. 73%) or in distilled water (37 degrees C). Then, strength data obtained were analyzed using two-parameter weibull statistics. In each condition, the bending strength data gave a good fit to single-mode weibull distribution. Weibull analysis of the data gave weibull parameter m = 7.8, sigma 0 = 26.2 MPa in air and m = 8.1, sigma 0 = 18.5 MPa in distilled water, which were calculated assuming a surface flaw model. The mean value of bending strength was 27.3 MPa in air and 18.2 MPa in distilled water. These results indicated that a corrosive environment such as H2O affects fracture stress when measured at a constant stress rate. This effect is considered to be caused by slow crack growth of cracks, occurring at a loading level lower than those at which specimens will fail. Using the weibull distribution function estimated in this study, the effects of both dimension of specimen and stress distribution in the specimen on the mean fracture stress have been predicted.

Air↗

[Estimation of fatigue parameter and life-time prediction using SPT diagram for hydroxyapatite coating layer in 37 degrees C distilled water].

Lifetime and survival probability of brittle materials under given conditions of stress distribution, environment and component size can be predicted using an SPT (Strenght-Probability-Time) diagram. The SPT diagram for sintered hydroxyapatite (HAP) coated on the metal substrate via the fused glass was drawn and the safe working stress in 37 degrees C distilled water was estimated. The dynamic fatigue test carried out in 37 degrees C distilled water gave the fatigue parameter n = 19 for sintered HAP. This parameter is constant except that it depends on material and environment, and the greater the value of n, the greater the resistance to fatigue failure. For sintered HAP, therefore, the resistance to fatigue failure under this wet condition is low. To draw the SPT diagram, anchor points were taken from the fracture stress and time-to-failure data measured at 1 mm/min. The SPT diagram obtained suggested that a lifetime of 20 years with survival probability of 99.9% required the safe working stress of less than 3.2 MPa. The effects of accuracy of fatigue parameter on the uncertainty in SPT diagram were estimated.

Corrosion↗

[Apatite-collagen complex. Preparation of a new apatite-collagen complex].

A new apatite-collagen complex was prepared in calcium beta-glycerophosphate solutions at pH 8.50. For this preparation, reconstituted type I collagen was cross-linked with phosvitin in the presence of alkaline phosphatase by use of a cross-linking agent of dimethyl suberimidate. After two weeks of immersion in daily-renewed solution of calcium beta-glycerophosphate, the complex contained apatite approximately two times the modified collagen in weight. When viewed in a scanning electron microscope, needle-like crystals precipitated densely on the collagen fibrils. However, in some portion of the complex, dot-like precipitate was observed as well. X-ray diffraction and IR analyses of the complex suggested that the apatite precipitated on the collagen fibrils was very similar to bone mineral in two aspects, crystallinity and carbonate content.

Apatites↗

[The effect of leukotriene C4/D4 receptor antagonist (ONO-1078) and thromboxane A2 synthetase inhibitor (OKY-046) on airway hyperresponsiveness induced by ozone exposure in guinea pigs].

To clarify the mechanisms of ozone-induced airway hyperresponsiveness, we studied the effect of leukotriene C4/D4 receptor antagonist (ONO-1078) and thromboxane A2 synthetase inhibitor (OKY-046) on airway hyperresponsiveness induced by ozone exposure in guinea pigs. Airway responsiveness to inhaled methacholine was determined in artificially ventilated guinea pigs using a modification of the Konzett-Rössler technique. After the methacholine challenge, bronchoalveolar lavage (BAL) was performed. After 1 hour following ozone exposure (2.9 ppm, 30 min), airway responsiveness increased significantly. There was no cellular change in the bronchoalveolar lavage fluid (BALF). Pretreatment with ONO-1078 (30 mg/kg, i.p.) or OKY-046 (20 mg/kg, i.p.) caused no effect on airway responsiveness before ozone exposure, and inhibited the increase of airway responsiveness induced by ozone exposure. These results suggest that leukotriene and thromboxane play an important role in the development of airway hyperresponsiveness induced by ozone exposure in guinea pigs.

Acrylates↗

[The effect of leukotriene B4 inhalation on airway responsiveness in dogs].

We studied the effect of leukotriene B4 (LTB4) inhalation on airway responsiveness in 12 dogs. LTB4 (10 micrograms/ml) was delivered as an aerosol, generated from a Devilbiss 646 nebulizer for ten minutes. Airway responsiveness to inhaled methacholine was determined by modified Astograph (7 Hz oscillation method) 1 hr (n = 6) and 6 hr (n = 6) after LTB4 inhalation. After measurement of airway responsiveness, total cell counts, differential cell counts, thromboxane B2 (TxB2) and 6-keto-prostaglandin (PG)F1 alpha levels in bronchoalveolar lavage fluid (BALF) were measured. The total cell counts in BALF increased after LTB4 inhalation (p less than 0.05), and the neutrophil counts in BALF increased significantly 1 hr (p less than 0.05) and 6 hr after (p less than 0.01) LTB4 inhalation. Airway responsiveness to inhaled methacholine decreased significantly 1 hr (p less than 0.05) and 6 hr (p less than 0.01) after LTB4 inhalation. There were no significant changes in the levels of TxB2 or 6-keto-PGF1 alpha in BALF 1 hr and 6 hr after LTB4 inhalation. These results suggest that inhaled LTB4 causes neutrophil recruitment into the airway but does not increase airway responsiveness to inhaled methacholine, and the possibility that LTB4 reduces airway responsiveness to inhaled methacholine exists in dogs.

Administration, Inhalation↗

Potential Z-DNA elements surround the breakpoints of chromosome translocation within the 5' flanking region of bcl-2 gene.

In follicular lymphoma the majority of t(14;18) chromosome translocations occur at the 3' region of the bcl-2 gene and are juxtaposed to the J region of the immunoglobulin heavy chain gene. Direct involvement of the putative V-(D)-J recombinase in the translocation has been proposed, since the hot spot region of the breakpoints on chromosome 18 possesses the 7/9 signal-like sequence. The 5' flanking region of bcl-2 gene is another hot spot of the translocations which are preferentially associated with chronic lymphocytic leukemia. The translocation in chronic lymphocytic leukemia results in the juxtaposition of the bcl-2 gene to various regions on the immunoglobulin light chain loci. No association of a 7/9 signal sequence and the heterogeneity of the breakpoints within the bcl-2 and IgL loci suggest that the translocations occurring at the 5'-flanking region of the bcl-2 gene might be mediated by a different mechanism from that of the t(14;18) translocation. Here we demonstrate that the breakpoints at the 5' flanking region of bcl-2 gene are surrounded by multiple alternating purine-pyrimidine elements (potential Z-DNA). The antibodies specific to Z-DNA showed that the regions containing the alternating purine-pyrimidine elements were confined to the 5' hot spot region. The data suggest that Z-DNA formation may be involved in chromosome translocations at the 5' flanking region of bcl-2 gene.

Base Sequence↗

[The role of thoracoscopy in pleural biopsy in cases with pleural effusion].

Between April 1985 and July 1989, 125 cases with pleural effusion were admitted to our department. The causes of pleural effusion were carcinomatous pleurisy in 47 cases, infection without tuberculosis in 34 cases, tuberculous pleurisy in 17 cases, cardiac insufficiency and hypoproteinemia in 11 cases, trauma and pneumothorax in nine cases, collagen disease in two cases and unknown origin in five cases. Carcinomatous pleurisy and tuberculous pleurisy, the differential diagnosis of which is very important, comprised 37% and 14% of all cases, respectively. These diseases can be definitively diagnosed by pleural biopsy, effusion cytology and/or effusion culture. In July 1987, we introduced thoracoscopy to improve the ratio of definitive diagnoses. The ratio for carcinomatous pleurisy in the previous term, when thoracoscopy was not being used, was 59%, while that in the latter term, when it was used, was 73%. The ratio for all cases with tuberculous pleurisy was 47%. Prior to June 1987, pleural biopsies in our department were performed with a Cope needle. Using that procedure, a low positive ratio of 50% was obtained. For thoracoscopic pleural biopsies, a high positive ratio of 84% was achieved (in carcinomatous pleurisy, 13 out of 15 cases; in tuberculous pleurisy, three out of four cases). This procedure was performed with minimal patient discomfort and no serious complications. Therefore, thoracoscopic pleural biopsy is recommended as a diagnostic procedure for cases with pleural effusion.

Adult↗

[Four cases of simultaneous discovery of familial tuberculous infection].

Index case is a 17-year-old boy who was admitted to our hospital with pleurisy and a minimal pulmonary lesion, and tubercle bacilli were recovered from pleural fluid. A diagnosis of primary tuberculosis was made based on the onset by pleurisy and the existence of hilar and mediastinal lymph node swelling. On the same day, a 76-year-old man, grandfather of the index case was admitted for precise examination of suspected extensive pneumonia. Tubercle bacilli were also isolated from the pus of infected bulla obtained by puncture. Neither of these two cases, however, seemed to be the source of the familial tuberculous infection because of such sudden onset of the disease as pleurisy and pneumonia. Two months later, a 46-year-old man, father of the index case was examined at our hospital. He was considered to be the source of the familial infection because he was diagnosed as tuberculosis with positive smear and a thick wall cavity (3.2 cm in diameter) on the left apex, and abnormal shadow was detected on his chest X-ray already two years ago. The fourth case was a mother of the index case, and wife of the third case, whose chest radiography revealed an infiltrative shadow on the right apex by a family contacts examination. Though tubercle bacilli were not isolated from her sputum, pulmonary lesions considered to be tuberculosis due to their typical location and nature, a positive PPD skin test, and the response to antituberculous drugs.

Adolescent↗