Biomedical subjects

N Nagata

Publications and source records attributed to N Nagata.

At least 181 records · Page 10Linked to original sources

PubMed1996

Bisphosphonates act on osteoblastic cells and inhibit osteoclast formation in mouse marrow cultures.

We examined the mode of action of bisphosphonates on osteoclastic cell recruitment using mouse marrow cultures with or without osteoblastic cells. Tartrate-resistant acid phosphatase-positive multinucleated cells [TRAP(+)MNC] formed in cultures were determined to be osteoclastic cells. In marrow cultures, TRAP(+) MNC formation in the presence of 10(-8) mol/L 1,25(OH)2D3 was not affected by the addition of 10(-6) mol/L dihydrogen (cycloheptylamino)-methylenebisphosphonate monohydrate (YM175). However, it was inhibited in cocultures of marrow cells with osteoblastic cells. The inhibitory effect was evident throughout the entire culture period. YM175 dose dependently inhibited TRAP(+) MNC formation, and other bisphosphonates--pamidronate and alendronate--also inhibited TRAP(+) MNC formation in the coculture. Similar observations were also made in the coculture of spleen cells with osteoblastic cells. The conditioned media of osteoblastic cells treated with 10(-6) mol/L YM175 inhibited TRAP(+) MNC formation in marrow cultures. The presence of YM175 in methylcellulose cultures affected neither the colony formation of monocyte-macrophage lineage, nor TRAP(+) MNC formation in the succeeding cocultures of recovered cells with osteoblastic cells. These results indicate that YM175 and probably other bisphosphonates as well preferentially inhibit the later stage of osteoclastogenesis through its action on osteoblastic cells. Our findings suggest that part of the inhibitory action by osteoblastic cells in the presence of bisphosphonates is mediated through soluble factor(s).

Acid Phosphatase↗

PubMed1996

Cardiac oxygenation by extracorporeal membrane oxygenation in exteriorized fetal lambs.

OBJECTIVE: The purpose of this study was to determine the degree of cardiac oxygenation produced by different routes of extracorporeal membrane oxygenation in fetal lambs submerged in warm saline solution. STUDY DESIGN: Seven fetal lambs ranging in age from 113 to 133 days of gestation were delivered by cesarean section and oxygenated with extracorporeal membrane oxygenation. To maintain the patency of the ductus arteriosus, prostaglandin E1 was continuously infused intravenously to the fetus. Initially the extracorporeal membrane oxygenation route was from the right atrium to the carotid artery. Then the extracorporeal membrane oxygenation route was changed to flow from the right atrium to the umbilical vein. The fetus was kept in a warm saline solution bath, and the fetal circulation was maintained. Extracorporeal membrane oxygenation flow ranged between 100 and 200 ml/min throughout the experiment. Simultaneous blood samples were taken during both types of extracorporeal membrane oxygenation from the following points in the fetal circulation: premembrane (least oxygenated blood leaving the fetus from the right atrium), postmembrane (oxygenated blood returning to the fetus), the carotid artery, and the left ventricle. The respiratory gases and pH of each sample were measured. Six fetuses received nonradioactive colored microspheres injected into the oxygenated blood returning to the fetus flow before returning to the fetuses during both types of extracorporeal membrane oxygenation. After the animals were killed, microspheres were counted in the myocardium separately taken from the right and left atria and the right and left ventricles to determine cardiac blood flow. RESULTS: During right atrium to carotid artery extracorporeal membrane oxygenation, left ventricle PO2 remained low as postmembrane PO2 increased; these values were not significantly correlated (r = 0.234, p = 0.61). During right atrium to umbilical vein extracorporeal membrane oxygenation, left ventricle and postmembrane PO2 exhibited a significant positive correlation (r = 0.855, p = 0.014). When the extracorporeal membrane oxygenation route was switched from the right atrium to carotid artery to the right atrium to umbilical vein, there was a significant increase in left ventricle PO2 and a decrease in left ventricle PCO2, whereas the respiratory gases and pH remained unchanged at other sites in the circulation. Microsphere counts were consistently higher during right atrium to umbilical vein extracorporeal membrane oxygenation than during right atrium to carotid artery extracorporeal membrane oxygenation in all four samples from different parts of myocardium (p < 0.001 by paired t test). CONCLUSION: More effective cardiac oxygenation is provided by right atrium to umbilical vein extracorporeal membrane oxygenation than by right atrium to carotid artery extracorporeal membrane oxygenation.

Animals↗

PubMed1996

Cyclic change of cytokines in a patient with cyclic thrombocytopenia.

The serial change of various cytokines in the serum from a patient with cyclic thrombocytopenia is described. Interleukin 7, stem cell factor, and transforming growth factor beta 1 synchronized with the platelet count, and there was a significant positive correlation between the three cytokines and the platelet count. Levels of macrophage colony-stimulating factor, thrombopoietin, platelet-associated IgG and erythropoietin changed reciprocally with the platelet count, and there was a significant negative correlation between the platelet count and these cytokines except erythropoietin. No cyclic change was observed in IL-3, IL-6, IL-11, granulocyte-macrophage colony-stimulating factor, or leukaemia inhibitory factor. These observations suggest that this disease involves two cyclic changes: megakaryocytopoiesis and platelet destruction, in both of which the cytokines play an important role.

Adult↗

PubMed1996

An aggressive nasal lymphoma accompanied by high levels of soluble Fas ligand.

Fas ligand (FasL), either in the membrane bound form or soluble form, has cytotoxic activity against Fas-expressing cells. We report a case of nasal lymphoma accompanied by liver damage and pancytopenia. The serum level of soluble FasL (sFasL) was very high on admission, but rapidly decreased to normal levels after chemotherapy for lymphoma. Liver damage and pancytopenia also improved with the decrease in serum sFasL. Since Fas is expressed on both hepatocytes and haemopoietic cells, these facts suggest that FasL was expressed on lymphoma cells and directly associated with pathogenesis of liver damage and pancytopenia through its cytotoxic activity.

Enzyme-Linked Immunosorbent Assay↗

PubMed1996

Glutathione S-transferase M1 (GSTM1) and T1 (GSTT1) genetic polymorphism and susceptibility to gastric and colorectal adenocarcinoma.

Genes coding for the glutathione S-transferase M1 (GSTM1) and Theta 1 (GSTT1) proteins are polymorphic in humans and these genes are absent, or homozygous null, in 10-60% of different ethnic populations. These enzymes catalyze the conjugation of glutathione to numerous carcinogenic chemicals and previous epidemiologic studies have associated the null genotypes of these GST genes with higher risk of cancer. In this study the frequency of GSTM1 and GSTT1 null genotypes was determined in Japanese patients with gastric adenocarcinoma and colorectal adenocarcinoma and compared to frequencies determined in a community-based control group. The frequency of the null GSTM1 genotype in patients with gastric adenocarcinoma (56.8%) showed a statistically significant increase compared to the control group frequency (43.6%) (odds ratio (OR) = 1.70; 95% CI, 1.05-2.76). The frequency of GSTM1 null individuals was also higher among all colorectal adenocarcinoma cases, but this increase did not reach statistical significance. After grouping by tumor site, the GSTM1 null genotype was a risk factor among the subgroup with distal colorectal tumors (61.1%) (OR = 2.03; 95% CI, 1.06-3.90). No consistent difference was observed between smoking patients and corresponding controls for the frequency of the GSTM1 null genotype for either cancer, although a large risk (OR = 5.76; 95% CI 1.18-28.3) was associated with the GSTM1 null genotype in the low smoking group of gastric adenocarcinoma patients. On the other hand, no statistically significant differences were observed in the frequency of null GSTT1 genotypes in gastric (47.5%) or colorectal (48.5%) adenocarcinoma patients when compared with the control population (44.4%). These results suggest that the GSTM1 null genotype may be associated with susceptibility to gastric adenocarcinoma and distal colorectal adenocarcinoma in Japanese; however, the associations observed were relatively weak and additional studies will be needed to confirm these findings.

Adenocarcinoma↗

PubMed1996

Amelioration of hyperglycemia in streptozotocin-induced diabetic rats receiving a marginal mass of islet grafts by troglitazone, an oral antidiabetic agent.

Troglitazone, a novel oral antidiabetic agent, was evaluated to determine whether it could have hypoglycemic effects in streptozotocin (STZ)-induced diabetic rats when a marginal mass of islets was transplanted and hyperglycemia persisted after transplantation. Lewis rats (RT1(1)) were used as both donors and recipients. Five hundred fresh islets were transplanted beneath the kidney capsule of STZ-induced diabetic recipients. Troglitazone was administered orally (0.34 mmol/kg/day) for 7 days before and for 60 days after islet transplantation. Neither troglitazone treatment without islet transplantation (n = 8) nor islet transplantation alone (n = 7) could produce normoglycemia (< 11 mmol/L) in diabetic recipients by 60 days after transplantation. In marked contrast, seven of 10 rats receiving islet grafts and treated with troglitazone became normoglycemia at 26.9 +/- 16.4 days (mean +/- SD; n = 7) after transplantation. Removal of the kidney bearing the grafts promptly resulted in the normoglycemic recipients (n = 4) becoming diabetic again. Light and electron microscopically, the intact islets with well-granulated beta cells could be observed in the transplant site of the normoglycemic recipients. These findings clearly demonstrate that the hyperglycemia in STZ-induced diabetic rats receiving an insufficient number of islet grafts to reverse diabetes was ameliorated by troglitazone treatment.

Animals↗

PubMed1996

Role of milk whey in the transmission of human cytomegalovirus infection by breast milk.

Breast-fed infants are susceptible to human cytomegalovirus (HCMV) infection via breast milk. In our previous study, HCMV was isolated more frequently from breast milk at later than one month after delivery than from colostrum or early breast milk. To clarify the role of milk cells and whey in vertical infection by breast feeding, we separated breast milk into milk cells and whey and examined each fraction for the presence of HCMV. We collected breast milk from mothers who breast-fed their infants (aged from 3 days to 2 months). The breast milk was centrifuged and separated into the middle layer (layer of milk whey) and the pellet (containing milk cells). We attempted to isolate HCMV from whey and to detect HCMV immediate early (IE) DNA in both milk whey and cells. HCMV was isolated from 7 out of 35 (20.0%) whey samples and HCMV IE DNA was detected from 15 out of 35 (42.9%) whey and/or milk cells. Detection rates of HCMV IE DNA in the whey layer and milk cells were 39.1% (25 out of 64) and 17.2% (11 out of 64), respectively. HCMV IE DNA was not detected in colostrum, but was detected in breast milk samples one month after delivery. Therefore, cell-free HCMV shed into milk whey may have a more important role in vertical infection by breast milk than cell-associated HCMV in the milk.

Base Sequence↗

PubMed1996

Congenital chylothorax in a patient with 21 trisomy syndrome.

A female infant with 21 trisomy syndrome associated with congenital chylothorax was reported. She was born at a gestational age of 34 weeks by Cesarean section because of fetal hydrothorax and hydrops fetus, confirmed by ultrasonography at 32 weeks. Emergent resuscitation and immediate thoracentesis were performed soon after birth. After beginning breast feeding, the serous pleural fluid became opalescent and a diagnosis of congenital chylothorax was made. Feeding was changed to medium-chain triglyceride (MCT) feeding and the production of pleural effusion disappeared after thoracentesis was performed several times. Accumulating evidence suggested that MCT feeding and intermittent thoracentesis under echo guide were effective. Some reports on patients, including this one, suggest that there may be more patients with 21 trisomy associated with congenital hydrothorax. Therefore, congenital hydrothorax might be listed as a complication of 21 trisomy.

Chylothorax↗

PubMed1996

Increased plasma adenosine deaminase activity in the early phase of Legionella pneumophila infection in guinea pigs.

We measured adenosine deaminase (ADA) activity in a guinea pig model of Legionella pneumophila infection. Female Hartley guinea pigs were inoculated intraperitoneally with one-quarter of the LD50 dose of L. pneumophila Philadelphia-1 strain. Control groups were inoculated with clinical isolates of Staphylococcus aureus, Streptococcus pneumoniae, Haemophilus influenzae or Klebsiella pneumoniae. Each group consisted of 5 animals. ADA activity in plasma was assayed calorimetrically before and at various intervals after infection by measuring the amount of ammonia produced after adenosine was added to plasma samples. ADA activity before inoculation was 25.6 +/- 6.0 IU/1, it reached 174.4 +/- 60.0 IU/1 on day 3 after inoculation of L. pneumophila. ADA activity returned to normal levels on day 14. ADA activity did not increase significantly in guinea pigs infected with the other types of bacteria. These findings suggest that measurement of plasma ADA activity may be useful for the diagnosis of Legionella infection.

Adenosine Deaminase↗

PubMed1996

Human trehalase: characterization, localization, and its increase in urine by renal proximal tubular damage.

By using polymerase chain reaction, cDNA encoding human renal trehalase has been isolated. The partial amino acid sequence deduced by the cDNA showed homologies in rabbit, Tenebrio molitor and silkworm trehalase. Northern blots showed renal trehalase mRNA to be about 2.0 kb. To examine the properties of renal and urinary human trehalase, the trehalase cDNA was inserted in the pMAL-cRI vector downstream from the malE gene, which encodes maltose-binding protein. Transfection of the recombinant pMAL-cRI in Escherichia coli provided high levels of expression of the maltose binding protein-trehalase fusion protein. A rabbit was immunized with purified fusion protein, and antihuman trehalase antibodies were obtained. Immunoblot analysis disclosed that renal and urinary trehalase exhibited a molecular mass of about 75 kDa. Analysis by indirect fluorescent microscopy demonstrated that the enzyme located in only proximal tubular cells. Urinary trehalase activity was low in the healthy infants and elevated in patients with asphyxia. Markedly high activity was observed in a patient with Lowe syndrome. The immunoreactive urinary trehalase with 75 kDa was increased dependent on the elevation of the activity. On the basis of these findings, we conclude that the increase of urinary trehalase reflects the extent of renal tubular damage, and we propose that urinary trehalase can be a specific marker of renal tubular damage.

Amino Acid Sequence↗

PubMed1996

Comparison of alveolar septal inflammation to bronchoalveolar lavage in interstitial lung diseases.

We analyzed transbronchial lung biopsy (TBLB) specimens by morphometry using a computer-aided graphic analyzer to quantify the severity of alveolar septal inflammation and investigated the correlation between the severity of inflammation and bronchoalveolar lavage fluid (BALF) lymphocyte content in various types of interstitial lung disease (ILD). Bronchoalveolar lavage was performed in the right S4 or S5 with 3 x 50 ml of sterile saline in 55 hospitalized patients with ILD between 1989 and 1993. Fluoroscopy-guided TBLB was then performed in the right S1, S2, S8, and S9. The severity of alveolar septal inflammation in TBLB specimens was quantified and expressed as the linear density of mononuclear cells infiltrating the alveolar septum. The severity of alveolar septal inflammation was not correlated with BALF lymphocyte content in the overall study populations (n = 55, p = 0.55), but was significantly correlated with BALF lymphocyte content in patients with hypersensitivity pneumonitis (n = 7, p = 0.021). No positive correlation was observed in patients with other types of ILD such as sarcoidosis (n = 17, p = 0.71), interstitial pneumonitis/fibrosis (n = 22, p = 0.98) or pneumoconiosis (n = 9, p = 0.48).

Alveolitis, Extrinsic Allergic↗

PubMed1996

Physiological levels of calcitonin regulate the mouse osteoclast calcitonin receptor by a protein kinase Alpha-mediated mechanism.

We have reported that calcitonin (CT) treatment induced downregulation of the CT receptor (CTR) in mouse osteoclast-like cells (OCLs). Here, we studied the features of homologous down-regulation of the CTR in mature mouse OCLs. Treatment with salmon CT (sCT) and human CT (hCT) reduced [125I]sCT specific binding. The decreased binding after 24 h of CT treatment was associated with a decrease in the cell surface receptor concentration. The extent of CT-induced down-regulation in 24 h was dose-dependent, and the ED50 value was 3.6 +/- 4.1 (mean +/- SD; n = 3) x 10(-13 M for sCT and 4.9 +/- 3.3 x 10(-11) M for hCT. These values were very similar to those for the CT inhibition of the bone-resorbing activity of OCLs. The data suggest that these two distinct actions of CT may be mediated by a common intracellular pathway. Treatment of OCLs with activators of protein kinase A (PKA) mimicked the effect of CT on CTR downregulation, whereas neither activation of protein kinase C nor elevation of intracellular Ca2+ did so. Attenuation of CT-induced CTR down-regulation by the competitive cAMP antagonist, RpcAMP, and high concentrations of H-7, but not by protein kinase C-specific inhibitors (sphingosine, staurosporine, and a lower concentration of H-7), suggested that the PKA pathway is primarily involved in homologous regulation of the CTR. The changes in CTR messenger RNA confirm the findings in binding studies and demonstrate that CT treatment of OCLs results in decreased CTR synthesis through the PKA pathway. The low concentrations of hCT that result in CTR regulation are very close to the physiological range, providing new insights into a dynamic relationship between circulating levels of CT and CTR expression in osteoclasts.

Animals↗

PubMed1996

Calcitonin receptor down-regulation relates to calcitonin resistance in mature mouse osteoclasts.

We have reported that short calcitonin (CT) treatment of mature mouse osteoclast-like cells (OCLs) in culture induced prolonged down-regulation of the CT receptor (CTR) and desensitization to CT rechallenge, at the level of adenylate cyclase activity. In this study, we have extended those studies to examine the bone resorbing activity of OCLs pretreated with CT. OCLs, which formed on gelled type I collagen, were pretreated with salmon CT (sCT)(10(-9)M, 1 h) and 24 h later were replated onto plastic dishes or dentine slices after removal from the gel by collagenase digestion. The number and population of either mononuclear or multinuclear OCLs that adhere to either surface was not affected by sCT pretreatment. It was found that OCLs pretreated with sCT regained reduced but significant bone resorbing capacity, which was quantitated as the surface area resorbed by OCLs on dentine slices. However, compared with control, the number of resorption pits produced by sCT- pretreated OCLs was slightly reduced, and the total pit area was decreased by approximately 40-50%. The distribution of individual pit sizes was altered by sCT-pretreatment so that the number of larger pits was predominantly reduced, suggesting that short sCT treatment may produce a long lasting decrease in osteoclast mobility. sCT was able to inhibit bone resorption activity of CT-pretreated OCLs (ED50:10(-13)-10(-12)M). Importantly, the ED50 of sCT inhibition of bone resorption in sCT-pretreated OCLs was approximately 100-fold greater than for control, indicating resistance of the OCLs to CT rechallenge. Consistent with these results, treatment of OCLs with sCT greatly decreased the expression of CTR messenger RNA, whereas no significant effect was observed on the tartrate-resistant acid phosphatase messenger RNA expression, a marker of resorptive capacity of osteoclasts. These results indicate, therefore, that an important component of escape of osteoclastic resorption from CT inhibition is CT resistance of mature osteoclasts, which regain bone resorbing function.

Animals↗

PubMed1996

Inhibitory effect of glycyrrhetinic acid derivatives on capsaicin-induced ear edema in mice.

We examined the effect of glycyrrhetinic acid (Ia) and its derivatives on ear edema induced by topical application of capsaicin in mice. Three dihemiphthalate compounds: di-sodium salt of 18 beta-olean-12-ene-3 beta,30-diol (deoxoglycyrrhetol, IIa) di-O-hemiphthalate (IIb); 18 beta-olean-9(11),12-diene-3 beta, 30-diol di-O-hemiphthalate (IIIa); and olean-11,13(18)-diene-3 beta,30-diol di-O-hemiphthalate (IVa) inhibited capsaicin-induced edema with ED50 values of 52.6, 41.0 and 51.8 mg/kg (p.o.), respectively. However, glycyrrhetinic acid and deoxoglycyrrhetol at a dose of 200 mg/kg (p.o.) had no effect. Compound IIIa (100 mg/kg, p.o.) also inhibited the edema response to capsaicin in mast cell-deficient mice. Furthermore, compounds IIb, IIIa and IVa (25-100 mg/kg, p.o.) prevented ear edema in response to intradermal injection of substance P (SP) and compound 48/80. In addition, these compounds at a high dose of 100 mg/kg (p.o.) produced a significant inhibition of the plasma extravasation in ear skin induced by i.v. administration of SP. The above results suggest that the effect of these compounds on capsaicin-induced ear edema is due at least in part to an inhibition of the increase of vascular permeability induced by vasoactive agents released from mast cells. Moreover, it seems likely that these compounds at a high dose can suppress vasodilatation and plasma extravasation induced by SP involved in capsaicin-induced edema.

Administration, Topical↗

PubMed1996

The movements of fetuses with congenital myotonic dystrophy in utero.

The movements in two fetuses with congenital myotonic dystrophy were recorded on fetal actocardiograms. The two fetuses showed gross movements associated with FHR accelerations as normal fetus. One of them showed swallowing on amniofetogram, and hiccuping on fetal actocardiogram. Both, however, were extremely hypotonic and neither displayed any gross movement, respiratory movement or swallowing postnatally. Intubation and nasal feeding were required for a long period of time after birth in both cases. The buoyancy of amniotic fluid may help the affected fetus to make gross movement in utero.

Adult↗

PubMed1996

Age associated changes in the distribution of lpr gene-induced B220-positive T cells in lymphoid organs of MRL/Mp-lpr/lpr mice using dual exposure microphotographs of double immunofluorescence staining.

Homozygous MRL/Mp-lpr/lpr [MRL/lpr] mice, which have an autosomal recessive mutant lpr gene and exhibit defects in Fas antigen, spontaneously develop autoimmune disease with progressive expansion and accumulation of characteristic abnormal CD4-CD8-double negative T cells that express B220 surface antigen, a B cell-specific surface marker in normal mice. We analyzed the distribution and age related changes of lpr gene-induced abnormal T cells (B220-positive lpr T cells) in the lymphoid organs of MRL/lpr mice. We studied cryostat sections of the spleen, peripheral lymph nodes, mesenteric lymph nodes, and Peyer's patches at different stages using FITC [fluorescein isothiocyanate)-conjugated monoclonal antibodies directed against B220 (RA3-6B2) and PE (phycoerythrin)-conjugated anti-mouse CD3 (2C11) monoclonal antibody, examining dual-exposure microphotographs of double-immunofluorescence stained preparations. We observed that in aged MRL/lpr mice, B220-positive abnormal lpr T cells were not present in the thymus-dependent area, and the majority of the follicular area cells were displaced by lpr T cells. These findings suggest that the cellular trafficking of B220-positive lpr T cells differs from that of conventional T cells and that these lpr-derived T cells play a role in the follicle.

Aging↗

PubMed1996

Augmentation of antitumor immunity using genetically M-CSF-expressing L1210 cells.

Macrophage colony-stimulating factor (M-CSF) enhances tumoricidal activities of macrophages. We transduced human M-CSF cDNA into the mouse lymphoid cell line, L1210, and examined the antitumor effect of the locally expressed M-CSF. Mice injected with the M-CSF-producing subline showed improved survival in comparison with the mock-transfected cell line or parental cell line plus M-CSF administration (20 microg/kg for 3 days) at inoculated cell numbers of 10(2) or 5 x 10(3). The survival rate at 50 days after injection of 10(6) high M-CSF-expressing cells was 80%, significantly higher than that after injection of the mock-transfected cells, which killed all the mice by day 23. The survival rate appeared to depend on the amount of M-CSF produced. Moreover, all surviving mice after intravenous injection of the M-CSF-expressing sublines were rechallenged with 10(6) parental L1210 cells at day 50, and all survived up to day 100, demonstrating that M-CSF-expressing cells induced immune protection against the parental cells. The same improvement of survival was observed in mouse M-CSF-expressing cell lines. These observations imply that M-CSF cDNA is a candidate gene for use in gene therapy in leukemia.

Animals↗

PubMed1996

[Anomalous origin of the left coronary artery from the pulmonary artery coronary revascularization under normothermic coronary perfusion in an infant].

A 5-months-old baby was hospitalized with congestive heart failure. Anomalous origin of the left coronary artery from the pulmonary artery was diagnosed on echo cardiography and coronary angiogram. Preoperative examination revealed severe left ventricular dysfunction (left ventricular end-diastolic pressure was 32 mmHg, left ventricular ejection fraction was 16%). Coronary revascularization was performed by anastomosis of the neo-left coronary artery to the aorta using an autologous pulmonary arterial roll under normothermic coronary perfusion. Although postoperative CPK-MB was within normal limits, the patient died on the 12th postoperative day due to ventricular arrythmia. Autopsy revealed severe endomyocardial fibroelastosis.

Cardiac Surgical Procedures↗