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Biomedical subjects

Y Kozuka

Publications and source records attributed to Y Kozuka.

At least 19 recordsLinked to original sources
PubMed2006

B cells play an important role in lipopolysaccharide-induced bone resorption.

The host immune system, especially activated T cells, plays a crucial role in inflammatory bone resorption and osteoclastogenesis. Previously, we showed that T cells are involved in inflammatory bone resorption in vivo. However, little is known about whether B cells are involved in inflammatory bone resorption and how B cells take part in osteoclastogenesis. Therefore, the aim of this study was to examine whether B c ells truly influence inflammatory bone resorption in vivo. Alveolar bone resorption in normal mice, in SCID mice that lack both B and T cells, and in B cell-reconstituted SCID mice was compared histopathologically after repeated injections of lipopolysaccharide (LPS) into the gingiva. Furthermore, we examined whether the B cells that are stimulated by LPS are involved in osteoclastogenesis in vitro. As a result, the B cell-reconstituted SCID mice showed stronger inflammatory bone resorption than the SCID mice. Also, in vitro, LPS-stimulated B cells enhanced osteoclastogenesis and anti-tumor necrosis factor (TNF)-alpha antibody completely blocked osteoclastogenesis induced by LPS-stimulated B cells. These results suggest that B cells promote inflammatory bone resorption through TNF-alpha.

Animals↗
PubMed2001

Recovery of infectious human parainfluenza type 2 virus from cDNA clones and properties of the defective virus without V-specific cysteine-rich domain.

A full-length cDNA clone was constructed from the genome of the human parainfluenza type 2 virus (hPIV2). First, Vero cells were infected with recombinant vaccinia virus expressing T7 RNA polymerase, and then the plasmid encoding the antigenome sequence was transfected into Vero cells together with polymerase unit plasmids, NP, P, and L, which were under control of the T7 polymerase promoter. Subsequently, the transfected cells were cocultured with fresh Vero cells. Rescue of recombinant hPIV2 (rPIV2) from cDNA clone was demonstrated by finding the introduced genetic tag. As an application of reverse genetics, we introduced one nucleotide change (UCU to ACU) to immediate downstream of the RNA-editing site of the V gene in the full-length hPIV2 cDNA and were able to obtain infectious viruses [rPIV2V(-)] from the cDNA. The rPIV2V(-) possessed a defective V protein that did not have the unique cysteine-rich domain in its carboxyl terminus (the V-protein-specific domain). The rPIV2V(-) showed no growth in CV-1 and FL cells. Replication of the rPIV2V(-) in these cells, however, was partially recovered by adding anti-interferon (IFN)-beta antibody into the culture medium, showing that the rPIV2V(-) is highly sensitive against IFN and that no growth of rPIV2V(-) in CV-1 and FL cells is mainly due to its hypersensitivity to endogenously produced IFN. These findings indicate that the V-protein-specific domain of hPIV2 is related to IFN resistance. On the other hand, the rPIV2V(-) efficiently replicated in Vero cells, which are known as a IFN-non-producers. However, the virus yields of rPIV2V(-) in Vero cells were 10- to100-fold lower than those of control rPIV2, although syntheses of the viral-specific proteins and their mRNAs in rPIV2V(-)-infected Vero cells were augmented up to 48 p.i. in comparison with those of rPIV2. Furthermore, the rPIV2V(-) virions showed anomalous in size as compared with rPIV2 virions. These results suggest that the V protein plays an important role in the hPIV2 assembly, maturation, and morphogenesis.

Animals↗
PubMed2001

[A case of pulmonary edema after electroconvulsive therapy under propofol anesthesia].

Electroconvulsive therapy (ECT) was scheduled for a 61-yr-old woman with major depression who had been taking a beta-blocker for hypertension. She underwent the first ECT under thiamylal anesthesia uneventfully. The second ECT was performed under propofol anesthesia on the next day. Immediately after ECT, the heart rate dropped from 56 to 19 beats.min-1, which was remedied by intravenous atropine. Then, the blood pressure increased to 204/108 mmHg but it was controlled by nicardipine. However, the SpO2 decreased to 84-88% under oxygen administration by mask at a rate of 3 l.min-1. The patient complained of chest discomfort and had a bloody secretion from the trachea. A chest X-ray showed a butterfly shadow. The patient was diagnosed as having neurogenic pulmonary edema and was treated in the ICU by artificial ventilation and administration of diuretics and catecholamines. These treatments proved to be successful, and the patient was discharged from the ICU 4 days later uneventfully. This case indicates that hemodynamics should be carefully monitored following ECT and that care should be taken to prevent the occurrence of complications after ECT.

Anesthesia, Intravenous↗
PubMed2000

Incomplete replication of human parainfluenza virus type 4 in LLC-MK2 cells and in L929 cells.

Human parainfluenza virus type 4A (hPIV-4A) and type 4B (hPIV-4B) were tested for their ability to replicate in the monkey kidney LLC-MK2 cell line (MK2 cells) and the murine L929 cell line (L929 cells). These cells are normally non-permissive for replication of hPIV-4; however, treatment with acetylated trypsin led to virus replication in MK2 cells, but was less effective for L929 cells. Endogenously produced interferon (IFN) played no role in virus replication in L929 cells. Synthesis of virus-specific polypeptides was suppressed in L929 cells. Whereas NP-mRNA and HN-mRNA were detected in MK2 cells, no HN-mRNA was detected in L929 cells. These results indicate that hPIV-4 can infect both MK2 cells and L929 cells. In MK2 cells, when protease exists in the extracellular medium, hPIV-4 exhibits multistep growth. In L929 cells, however, the cause of incomplete replication might be lack of other unknown factors.

Animals↗
PubMed2000

Osmium-metal coating device using hollow-cathode plasma CVD method.

A novel osmium-metal coating device for SEM observation has been developed to prevent negative charge build-up on specimens by applying the hollow-cathode low voltage discharge plasma chemical vapour deposition (CVD) method. The CVD method using the hollow-cathode offers the following advantages. (i) The method can deposit osmium-metal at very low discharge voltage that is as low as half of that of the planar parallel electrode method. Therefore, the method avoids damage due to ion bombardment during the coating process. (ii) The method can minimize the quantity of the OsO4 gas by introducing directly into the hollow-cathode. This feature is important to prevent the air pollution caused by the purged gas. (iii) A large coating area is guaranteed because the Os ion is filled in the hollow-cathode where the specimen is holed. (iv) The lower discharge voltage can be used by mixing Ar, N2 or air with the OsO4 gas as the environmental gas in the chamber. (v) The hybrid coating is also available by lining the appropriate metal material such as platinum (Pt) on the surface of the inside of the hollow-cathode. The method uses the plasma CVD of Os metal as well as the ion-sputter deposition of the lined metal.

Animals↗
PubMed1999

Isolation and characterization of monoclonal antibodies directed against murine FRP-1/CD98/4F2 heavy chain: murine FRP-1 is an alloantigen and amino acid change at 129 (P<-->R) is related to the alloantigenicity.

Nineteen mAb directed against murine fusion regulatory protein-1 (mFRP-1)/4F2/CD98 were isolated and their biological properties were analysed. Intriguingly, mFRP-1 was found to be an alloantigen, namely, FRP-1.1 (DBA/2 and CBA mice type) and FRP-1.2 (BALB/c, C57BL/6 and C3H/He mice type). The nucleotide sequences of FRP-1.1 and FRP-1.2 were determined, demonstrating that amino acid change at 129 (P<-->R) is related to the alloantigenicity. mFRP-1 is expressed on thymocytes, on spleen cells, on peripheral lymphocytes and on blood monocytes, suggesting that the physiological role in vivo of murine FRP-1 is different from that of human FRP-1. The biological activities of antimFRP-1 mAbs showed by the present study are: (i) enhancement of Newcastle disease virus-induced cell fusion; (ii) suppression of HIVgp160-mediated cell fusion; and (iii) induction of aggregation and multinucleated giant cells of monocytes/macrophages.

Amino Acid Sequence↗
PubMed1997

[Successful surgical treatment for type B aortic dissection with Marfan's syndrome after aortic root and mitral valve replacement: report of a case].

A 30-year-old female with Marfan's syndrome underwent aortic root replacement for annuloaortic ectasia and mitral valve replacement for mitral regurgitation. She remained well until 16 months postoperatively when she had sudden onset of pain. Preoperative angiogram showed Stanford B aortic dissection. Thoracoabdominal aortic replacement was performed successfully under deep hypothermic bypass.

Adult↗
PubMed1997

[Reoperation for mitral regurgitation 13 years after aortic valve replacement and manouguian's anulus enlargement: report of a case].

The patient was 22-year-old female. She had undergone aortic valve replacement and Manouguian's anulus enlargement with low porosity woven Dacron patch for congenital aortic stenosis 13 years ago, and developed mitral regurgitation 9 years after that operation. Two regurgitant flow were observed. One was originated from the orifice due to mitral prolapse. The other was from a tear in the anterior leaflet. It was around the tip of the prosthetic patch, approximately 7 mm in size, and was repaired easily. But the mitral valve itself was found to be malformed and prolapsed, requiring mitral valve replacement. Her postoperative course was uneventful.

Adult↗
PubMed1995

Effect of ibudilast on ciliary activity of human paranasal sinus mucosa in vitro.

The effect of ibudilast (CAS 50847-11-5, 3-isobutyryl-2-isopropylpyrazolo[1,5-a]pyridine, KC-404), an anti-asthmatic drug, on ciliary beat frequency (CBF) of human paranasal sinus mucosa was examined in vitro. Ciliary activation was observed after a 10-min exposure to 4.6 x 10(-6) mol/l ibudilast. Ibudilast dose-dependently increase CBF at the concentrations ranging from 4.6 x 10(-7) mol/l to 4.6 x 10(-5) mol/l. Propranolol inhibited ciliary activity induced by ibudilast; however, neither indometacin nor verapamil affected the activation of ibudilast on CBF. Platelet activating factor (PAF) and Leukotriene D4 (LTD4) are chemical mediators inducing mucosal dysfunction and damage. Ibudilast prevented ciliary inhibition induced by PAF and LTD4. These findings indicated that ibudilast activates CBF and inhibits the effect of PAF and LTD4 on ciliated cells, and consequently improves the pathogenesis of allergic disorders such as the inhibited mucociliary transport system and airway hyperresponsiveness.

Bronchodilator Agents↗
PubMed1994

[Pollen of gramineae and its botanical, taxonomical, and ecological aspects].

This is a review of tropical pollens (Gramineae) which cause allergy, addressed to medical workers and with emphasis in the Costa Rican. The graminean family Poaceae is widely distributed and has great genetic plasticity. An evolutionary tendency to floral reduction has led to anemophily, with pollens ranging from large (e.g. corn, Zea mays) to very small (e.g. tribes Poae and Avenae). This family produces a large number of pollens per panicle. The early morning production of free pollen (before 8 am) enhances allergic problems. In contrast, in rice (Oryza sativa) most pollen is liberated near mid day, which favours long range dispersal because of more appropriate environmental temperature and humidity. This can explain why rice is the first cause of allergic sensitivization in the asthmatic patients of the Costa Rican driest provinces (Guanacaste and Puntarenas). Despite the small size of several temperate and tropical species are present, because of geographic position, climatic diversity, irregular topography, etc. This paper presents a general description of the subfamilies Pooideae, Panicoideae, Chlorideae (Eragrostoideae) and Oryzoideae (including the medically most important tribes). Their pollens are illustrated with light and electron microscopy.

Allergens↗
PubMed1992

Detection of free radicals in UV-irradiated lens by spin trapping ESR.

We have made an ESR study on the UV-photolysis of lens and identified the origins of free radicals involved in the initial photochemical process by spin trapping technique. Two spin adducts were detected on irradiation of canine lens in the presence of a spin trapping reagent (DMPO); a spin adduct of sulfur centered radical derived from glutathione and the protonated adduct of hydrated electron. A free radical mechanism of initial photochemical injury in UV-irradiated lens was discussed, comparing with a photolysis of tryptophan plus cysteine solution.

Animals↗
PubMed1986

[Immunohistochemical studies of fetal and maternal endocrine pancreases during pregnancy and the puerperium in streptozotocin-induced diabetic rats].

In order to clarify the influence of the diabetic state on the structure of maternal and fetal endocrine pancreases, the distribution of alpha, beta and delta cells in the islets of Langerhans (IL) was investigated by PAP methods in normal and streptozotocin (STZ)-induced diabetic rats. The size of the IL significantly increased during pregnancy and on day 14 of puerperium in normal and diabetic maternal rats. The total cell numbers of IL also increased during pregnancy but decreased in puerperium in both groups. Although the number of beta cells was reduced in STZ-treated rats, they could increase during pregnancy as in the normal group. The number of beta cells kept increasing in puerperium in the diabetic group, but not in the normal group. The number of alpha and delta cells in diabetic rats was greater than in normal rats but did not change remarkably during pregnancy and in puerperium. The IL of fetuses from diabetic mothers were slightly greater in size and number than those from normal mothers. The number of fetal beta cells from normal mothers was somewhat greater than that from diabetic mothers. The number of fetal alpha and delta cells from diabetic mothers was slightly greater than that from normal mothers. These findings, therefore, suggest that diabetic IL could adapt themselves to pregnancy-induced metabolic changes.

Animals↗
PubMed1986

[Studies on somatomedin C in diabetic pregnancies].

Somatomedins have been shown to have potent mitogenic activities in cultured cells and also promote individual growth. We studied the concentrations of somatomedin C in diabetic pregnant women and rats. Serum and liver somatomedin C were measured by RIA double antibody method, after extraction with an ODS silica column. Serum somatomedin C concentrations were 20.45 +/- 5.14 nM/l (mean +/- S.D.) in nonpregnant normal women. In nonpregnant diabetic women, these were 16.96 +/- 4.37 nM/l, which were significantly lower than those of normal nonpregnant women. The concentrations of pregnant normal and diabetic women were similar to those of nonpregnant normal women. Maternal concentrations of somatomedin C significantly correlated with infant weight (r = 0.41, p less than 0.05, n = 41). Serum somatomedin C concentrations in the normal infants were 6.45 +/- 1.97 nM/l, which were considerably lower than those of their mothers. In the infants from diabetic mothers, these were 9.17 +/- 3.28 nM/l, which were significantly higher than those of normal infants. Rat serum somatomedin C concentrations which were 15.86 +/- 2.37 nM/l in nonpregnant normal rats, tended to increase during pregnancy. The mother's concentration significantly correlated with fetus weight (r = 0.491). Liver somatomedin C levels decreased in diabetic and pregnant states. Fetal rats had lower hepatic somatomedin C, which was about 10% of the mother's levels. These were higher in the fetuses from diabetic mothers. These finding suggested that the mother's somatomedins might contribute to fetal growth.

Animals↗