Intraoperative map-guided operation for chronic atrial fibrillation

Intraoperative map-guided cryoablation for chronic atrial fibrillation and coronary artery bypass grafting were simultaneously performed in a 55-year-old man. Computerized atrial mapping revealed that regular and repetitive electrical discharges originated in the left atrial appendage. Without opening the left atrium, we successfully ablated atrial fibrillation with cryoablation on the epicardium of the left atrial appendage. Thus, intraoperative mapping should facilitate operations for atrial fibrillation.

Serum interleukin-6, interleukin-8, hepatocyte growth factor, and nitric oxide changes during thoracic surgery

Thoracic surgery creates a different environment from abdominal surgery in respect to the surgical procedure with pulmonary collapse under unilateral ventilation. Definitive evidence whether surgical trauma during thoracotomy is involved in postoperative pulmonary infections has not been clearly demonstrated. The objectives of this study were to evaluate the influence of surgical trauma during thoracotomy on postoperative infections and to investigate the clinical significance of postoperative humoral mediators in pulmonary infections after surgery. We measured serum interleukin-6 (IL-6), IL-8, hepatocyte growth factor (HGF), and nitric oxide (NO) levels in 27 patients undergoing thoracic surgery; the measurements were before and during thoracotomy, 60 minutes after reinflation, and after surgery. The patients were divided into three groups: lobectomy patients (group A), and esophagectomy patients without (group B) or with (group C) postoperative infections. The serum IL-6 and IL-8 levels in group C were markedly elevated 60 minutes after reinflation and were significantly higher than those in group A. The serum IL-8 levels during that period in group C were significantly higher than those in group B. The postoperative serum IL-6, IL-8, HGF, and NO levels were significantly higher in group c than in group B. Taken together, intraoperative hypercytokinemia, especially IL-8, following the thoracic procedure and subsequent reinflation preceded the clinical onset of postoperative infections. Hence postoperative serum IL-6, IL-8, and HGF levels may be useful predictors of infection after esophagectomy.

[The switching time of propofol syringes for the propofol specific pump is dependent on the familiarity of pumps]

The switching time of syringes during propofol anesthesia was investigated among various anesthesiologists. One hundred and thirty times of exchanges were observed in the early 82 propofol anesthesia cases using a propofol specific syringe pump STC-525 X (Terumo, Japan) since the introduction of propofol in our hospital. The anesthesiologists were divided into three groups: group A; the board certified anesthesiologists with more than one month experience of propofol anesthesia, group B; the board certificed anesthesiologists with less than one month experience, group C: the trainee. There were no cases of intraoperative recall case. The median times of switching syringes were 14 seconds, 26 seconds, 56 seconds in the group A, group B, group C, respectively. Group A is significantly quicker than the other groups. This indicates that switching time is dependent on the experience with propofol and syringe pumps. We conclude that not only trainees but also expert anesthesiologists should be accustomed to switching syringes in order to avoid intraoperative awareness.

Bifurcated dendritic cell differentiation in vitro from murine lineage phenotype-negative c-kit+ bone marrow hematopoietic progenitor cells

We have recently established the culture system to generate dendritic cells (DCs) from murine Lin-c-kit+ bone marrow hematopoietic progenitor cells (HPCs) in the presence of granulocyte-macrophage colony-stimulating factor (GM-CSF) + stem cell factor (SCF) + tumor necrosis factor-alpha (TNF-alpha). We present here the identification of two DC precursor subsets originated from HPCs with the phenotype of CD11b-/dullCD11c+ and CD11b+hiCD11c+ that develop independently at early time points (days 4 to 6) in the same culture conditions. Both of CD11b-/dullCD11c+ and CD11b+hiCD11c+ precursors could differentiate at day 10 to 14 into CD11b-/dullCD11c+ mature DCs with typical morphology, phenotype, and the ability to stimulate allogenic mixed leukocyte reaction (MLR). However, the endocytic capacity of fluorescein isothiocyanate-dextran was markedly reduced during the differentiation. CD11b-/dullCD11c+ precursors expressed high levels of Ia, CD86, CD40, and E-cadherin molecules, but not c-fms transcript, and mature DCs derived from this precursor subset continue to express abundant E-cadherin antigen, a discernible marker for Langerhans cells. In contrast, CD11b+hiCD11c+ precursors expressed c-fms mRNA, but low levels of Ia, CD86, and E-cadherin, whereas CD40 was undetectable. CD11b-/dullCD11c+ mature DCs differentiated from these precursors displayed abundant c-fms mRNA and nonspecific esterase activity. Interestingly, CD11b+hiCD11c+ precursors, but not CD11b-/dullCD11c+ precursors, may be bipotent cells that can be induced by M-CSF to differentiate into macrophages. All of these results suggest that CD11b-/dullCD11c+ and CD11b+hiCD11c+ cells are distinct DC precursors derived from Lin-c-kit+ HPCs, which differentiate into mature DCs through bifurcated and independent DC differentiation pathways.

Targeted disruption of mouse conventional kinesin heavy chain, kif5B, results in abnormal perinuclear clustering of mitochondria

Mouse kif5B gene was disrupted by homologous recombination. kif5B-/- mice were embryonic lethal with a severe growth retardation at 9.5-11.5 days postcoitum. To analyze the significance of this conventional kinesin heavy chain in organelle transport, we studied the distribution of major organelles in the extraembryonic cells. The null mutant cells impaired lysosomal dispersion, while brefeldin A could normally induce the breakdown of their Golgi apparatus. More prominently, their mitochondria abnormally clustered in the perinuclear region. This mitochondrial phenotype was reversed by an exogenous expression of KIF5B, and a subcellular fractionation revealed that KIF5B is associated with mitochondria. These data collectively indicate that kinesin is essential for mitochondrial and lysosomal dispersion rather than for the Golgi-to-ER traffic in these cells.

Physiologic regulation of postovulatory neutrophil migration into vagina in mice by a C-X-C chemokine(s)

Leukocytes, particularly neutrophils, infiltrate into female genital organs after ovulation in both humans and mice. In mice, a female sexual cycle consists of 5 phases: proestrus, estrus, metestrus-1, metestrus-2, and diestrus. Ovulation occurs at estrus; at metestrus-2, a large number of neutrophils infiltrate into the vaginal epithelium accompanied by an increased neutrophil number in vaginal lavage fluid. Concomitantly, concentrations of a functional IL-8 homologue, murine macrophage inflammatory protein (MIP)-2, were increased significantly in vaginal lavage fluid at metestrus-2 as compared with other phases. On the contrary, MIP-2 was not detected in plasma during the whole course of a sexual cycle. Moreover, immunohistochemical analyses demonstrated that MIP-2 protein expression was prominent at the upper layer of the vaginal epithelium at metestrus-2, in contrast to a marginal staining in the vaginal epithelium at proestrus and estrus. These results suggest that a C-X-C chemokine, MIP-2, was produced physiologically in the vaginal epithelium in a sexual cycle-dependent manner. Furthermore, the administration of neutralizing anti-IL-8R homologue Abs at proestrus abrogated leukocyte infiltration into the vagina at metestrus. However, anti-MIP-2 Abs reduced leukocyte influx at metestrus by approximately 50%. Thus, a murine IL-8 homologue, MIP-2, and its related molecules physiologically regulate neutrophil migration into the vagina in a sexual cycle-dependent manner.

QTc interval, and autonomic and somatic nerve function in diabetic neuropathy

QTc intervals were measured using an electrocardiogram and other autonomic function tests, in 66 neuropathy patients with non-insulin-dependent diabetes mellitus (59.0 +/- 12.5 years; mean +/- SD). The change in R-R interval did not influence the QTc interval, as calculated by the equation: QTc = QT + (1000 - R-R)/7 (ms), compared with the conventional Bazett's equation which appeared to overcompensate in the case of a small R-R interval. The QTc interval in the diabetic patients was significantly longer than that in age-matched controls. The QTc interval showed an inverse correlation with the coefficient of variation of the R-R interval and skin blood flow at rest. However, no correlation was found between QTc interval and blood pressure change, change in heart rate on standing, or results of the sympathetic skin response. The QTc interval did not correlate significantly with motor or sensory nerve conduction parameters. We conclude that the QTc interval can be a simple and useful autonomic indicator for diabetic neuropathy relatively independent of other abnormalities of autonomic and somatic nervous system function.

Right atrial isolation for atrial fibrillation associated with atrial septal defect

Two patients with atrial fibrillation associated with an atrial septal defect underwent simultaneous surgical correction of the atrial septal defect and right atrial isolation. The right atrium was surgically isolated while the continuity with the sinoatrial node was preserved in the remainder of the heart. After the operation, the patients maintained normal sinus rhythm for 99 and 65 months. Thus, right atrial isolation offers an alternative to the current surgical treatment for atrial fibrillation associated with an atrial septal defect.

Tiludronate inhibits interleukin-6 synthesis in osteoblasts: inhibition of phospholipase D activation in MC3T3-E1 cells

In previous studies, we have reported that PGF2alpha stimulates phosphoinositide hydrolysis by phospholipase C and phosphatidylcholine hydrolysis by phospholipase D through heterotrimeric GTP-binding protein in osteoblast-like MC3T3-E1 cells, and that PGF2alpha and PGE1 induce interleukin-6 (IL-6) synthesis via activation of protein kinase C and protein kinase A, respectively. In the present study, we investigated the effect of tiludronate, a bisphosphonate known to inhibit bone resorption, on the PGF2alpha- and PGE1-induced IL-6 synthesis in these cells. Tiludronate significantly suppressed the PGF2alpha-induced IL-6 secretion in a dose-dependent manner in the range between 0.1 and 30 microM. However, the IL-6 secretion induced by PGE1 or (Bu)2cAMP was hardly affected by tiludronate. The choline formation induced by PGF2alpha was reduced by tiludronate dose-dependently in the range between 0.1 and 30 microM. On the contrary, tiludronate had no effect on PGF2alpha-induced formation of inositol phosphates. Tiludronate suppressed the choline formation induced by NaF, known as an activator of heterotrimeric GTP-binding protein. However, tiludronate had little effect on the formation of choline induced by TPA, a protein kinase C activator. Tiludronate significantly inhibited the NaF-induced IL-6 secretion in human osteoblastic osteosarcoma Saos-2 cells. These results strongly suggest that tiludronate inhibits PGF2alpha-induced IL-6 synthesis via suppression of phosphatidylcholine-hydrolyzing phospholipase D activation in osteoblasts, and that the inhibitory effect is exerted at the point between heterotrimeric GTP-binding protein and phospholipase D.

Defect in synaptic vesicle precursor transport and neuronal cell death in KIF1A motor protein-deficient mice

The nerve axon is a good model system for studying the molecular mechanism of organelle transport in cells. Recently, the new kinesin superfamily proteins (KIFs) have been identified as candidate motor proteins involved in organelle transport. Among them KIF1A, a murine homologue of unc-104 gene of Caenorhabditis elegans, is a unique monomeric neuron- specific microtubule plus end-directed motor and has been proposed as a transporter of synaptic vesicle precursors (Okada, Y., H. Yamazaki, Y. Sekine-Aizawa, and N. Hirokawa. 1995. Cell. 81:769-780). To elucidate the function of KIF1A in vivo, we disrupted the KIF1A gene in mice. KIF1A mutants died mostly within a day after birth showing motor and sensory disturbances. In the nervous systems of these mutants, the transport of synaptic vesicle precursors showed a specific and significant decrease. Consequently, synaptic vesicle density decreased dramatically, and clusters of clear small vesicles accumulated in the cell bodies. Furthermore, marked neuronal degeneration and death occurred both in KIF1A mutant mice and in cultures of mutant neurons. The neuronal death in cultures was blocked by coculture with wild-type neurons or exposure to a low concentration of glutamate. These results in cultures suggested that the mutant neurons might not sufficiently receive afferent stimulation, such as neuronal contacts or neurotransmission, resulting in cell death. Thus, our results demonstrate that KIF1A transports a synaptic vesicle precursor and that KIF1A-mediated axonal transport plays a critical role in viability, maintenance, and function of neurons, particularly mature neurons.

Correlation between bone mineral density and intervertebral disc degeneration

STUDY DESIGN

Intervertebral disc area, disc bulge ratio, and bone mineral density were measured in 86 postmenopausal women and the data analyzed.

OBJECTIVE

To examine quantitatively the correlation between intervertebral disc degeneration and bone mass.

SUMMARY OF BACKGROUND DATA

In results of previous studies, an inverse correlation between osteoporosis and spondylosis has been reported. In these studies, only radiographic findings were used to evaluate spondylosis; changes in the intervertebral disc itself were not investigated.

METHODS

To determine bone mass, total-body bone mineral density, lumbar bone mineral density, and age-matched control values of bone mineral density were measured by dual-energy X-ray absorptiometry in all cases. To evaluate intervertebral disc degeneration, disc area and disc bulge ratio (calculated by measuring the areas protruding from lines connecting the middle points of the anterior and posterior borders of the vertebral bodies) were obtained from four discs, using magnetic resonance images of the lumbar spine. The correlation between bone mass data and disc area data was analyzed.

RESULTS

Bone mineral density showed a significant decrease with increasing age. Disc area and disc bulge ratio had no relation to age. There was a negative correlation between total-body bone mineral density, lumbar bone mineral density, and age-matched control values versus disc area, and a positive correlation between all bone mineral density data and the disc bulge ratio.

CONCLUSIONS

According to the results of the analysis by disc morphology and bone mass, especially total body bone mineral density, bone mass has an inverse correlation to intervertebral disc degeneration--i.e., reduction and disc bulge--which is important when considering degenerative spinal diseases and osteoporosis.

Golgi vesiculation and lysosome dispersion in cells lacking cytoplasmic dynein

Cytoplasmic dynein, a minus end-directed, microtubule-based motor protein, is thought to drive the movement of membranous organelles and chromosomes. It is a massive complex that consists of multiple polypeptides. Among these polypeptides, the cytoplasmic dynein heavy chain (cDHC) constitutes the major part of this complex. To elucidate the function of cytoplasmic dynein, we have produced mice lacking cDHC by gene targeting. cDHC-/- embryos were indistinguishable from cDHC+/-or cDHC+/+ littermates at the blastocyst stage. However, no cDHC-/- embryos were found at 8.5 d postcoitum. When cDHC-/- blastocysts were cultured in vitro, they showed interesting phenotypes. First, the Golgi complex became highly vesiculated and distributed throughout the cytoplasm. Second, endosomes and lysosomes were not concentrated near the nucleus but were distributed evenly throughout the cytoplasm. Interestingly, the Golgi "fragments" and lysosomes were still found to be attached to microtubules. These results show that cDHC is essential for the formation and positioning of the Golgi complex. Moreover, cDHC is required for cell proliferation and proper distribution of endosomes and lysosomes. However, molecules other than cDHC might mediate attachment of the Golgi complex and endosomes/lysosomes to microtubules.

Triiodothyronine modulates interleukin-6 synthesis in osteoblasts: inhibitions in protein kinase A and C pathways

In osteoblast-like MC3T3-E1 cells, we recently reported that PGE1 and PGF2alpha induce interleukin (IL)-6 synthesis via activation of protein kinase A and protein kinase C, respectively. Moreover, in the case of IL-1-induced IL-6 synthesis in these cells, we showed that protein kinase C activation by IL-1 limits the IL-6 synthesis. In the present study, we investigated the effect of T3 on IL-6 synthesis induced by these agonists in MC3T3-E1 cells. T3, which by itself had little effect on IL-6 synthesis, significantly reduced the IL-6 synthesis induced by PGE1 in a dose-dependent manner in the range between 10 pM and 10 nM. T3 also reduced PGE1-induced activation of protein kinase A. T3 inhibited the IL-6 synthesis induced by cholera toxin, an activator of Gs, or forskolin, which directly activates adenylate cyclase. However, T3 did not affect (Bu)2cAMP-induced IL-6 synthesis. In addition, T3 reduced PGF2alpha-induced IL-6 synthesis dose dependently in the range between 10 pM and 10 nM. T3 also inhibited IL-6 synthesis induced by 12-O-tetradecanoylphorbol-13-acetate, an activator of protein kinase C. On the other hand, T3 markedly enhanced IL-1-induced IL-6 synthesis. This enhancement by T3 was potentiated in protein kinase C down-regulated cells. T3 hardly affected the protein kinase C activation induced by PGF2alpha or IL-1. These results strongly suggest that T3 modulates IL-6 synthesis at two points in osteoblasts as follows; one is exerted at the point between adenylate cyclase and protein kinase A, and the other is at a point downstream from protein kinase C activation.

Interleukin-8 (IL-8) and monocyte chemotactic and activating factor (MCAF/MCP-1), chemokines essentially involved in inflammatory and immune reactions

Leukocyte infiltration is a hallmark of inflammation. Knowledge on molecular mechanisms of leukocyte infiltration has advanced rapidly due to the recent elucidation of structures and functions of adhesion molecules and chemokines. Since the discovery of interleukin-8 (IL-8), a prototype of CXC chemokines, in 1987 and monocyte chemotactic and activating factor/monocyte chemoattractant protein-1 (MCAF/MCP-1), a prototype of chemotactic cytokines (CC) chemokines, in 1989, more than 30 members of chemokines have been identified so far. Evidence is accumulating that these chemokines exert overlapping but distinct actions on specific types of leukocytes in vitro through interacting with their specific G-protein-coupled receptors with seven transmembrane domains. However, redundancy at receptor levels has frequently hindered the clarification on the precise physiological or pathophysiological roles of chemokines. Here, we describe the pathophysiological roles of IL-8 and MCAF/MCP-1 in several animal models of neutrophil- and macrophage-mediated inflammation, respectively, by focusing on our recent work using neutralizing antibodies to these chemokines. We discuss further potential roles of these chemokines in T-lymphocyte-mediated immune responses.

Immunohistochemical and molecular biological studies of serous cystadenoma of the pancreas

Seven cases of pancreatic serous cystadenoma were examined immunohistochemically and molecular biologically. Six were benign tumors and one was clinically malignant. Immunohistochemical studies were performed with the avidin-biotin peroxidase complex technique on paraffin-embedded tumor tissue and were stained with antibody to carcinoembryonic antigen (CEA), CA19-9, and p53 protein. Two-stage polymerase chain reaction-restriction fragment length polymorphism analysis was used to detect K-ras oncogene mutation at codon 12. No tumor cells were stained with anti-CEA and anti-p53 protein, but two cases were stained focally with anti-CA19-9. One case was benign and one was clinically malignant. In the anti-CA19-9 staining, tumor cells of the benign case were positive only on the apical membrane and supranuclear cytoplasm of the cells, whereas those of the clinically malignant case were positive over the entire surface and cytoplasm of the cells. All seven cases were without K-ras gene mutation. So the features of serous cystadenoma of the pancreas suggest a tumor genesis different from that of ductal adenocarcinoma. They also suggest a relationship between immunohistochemical localizations of CA19-9 in the tumor cells and the biological behavior of the tumor itself.

Successful use of single-lumen, urokinase immobilized femoral catheters as a temporary access for haemodialysis

METHODS

Placement of a femoral vein catheter as a temporary vascular access for haemodialysis was conducted and the indications, catheter patency rate, and incidence of catheter-related infections were examined. An urokinase immobilized femoral vein catheter (UIFC) is a soft polyurethane single-lumen catheter 2.7 mm in diameter and 22 cm in length which needs no heparin infusion (Japan Shawood Co., Ltd., Tokyo; Unitica Co., Ltd., Hyogo, Japan). A soft silicon rubber was attached to the tip of the catheter in order to avoid excessive bleeding during insertion. Aseptic adhesive wound dressing was employed at the exit-site which was cleansed with popidone-iodine and renewed at each dialysis session.

RESULTS

Eighty-one UIFCs were used for haemodialysis in 64 patients (acute renal failure: 11; vascular access trouble: 53; initiation of chronic dialysis: 17). The average age of the patients was 58 +/- 13 years, ranging from 26 to 80 years. The mean duration of catheter indwelling was 22.4 +/- 13.1 days. An adequate blood flow of 180-200 ml/min was obtained through UIFC and returned to another peripheral vein punctured at each dialysis session. Unexplained fever occurred in four cases while the UIFC was in place (4.9%) but culture of either blood or the catheter tip was negative for bacteria. The catheter was removed immediately and fever subsided in all cases. The overall catheter survival rate was 84% at 34 days calculated using the Kaplan-Meier method. Catheter insertion was easy to perform and no serious complications such as pulmonary embolism or septicaemia occurred.

CONCLUSION

Our modified type of UIFC is very useful as a temporary access for haemodialysis with a very low incidence of catheter-related infections and no need for heparinization. Excellent catheter patency was maintained with the plug system and careful dressing techniques without unnecessary bleeding during catheter care.

Induction of dendritic cell differentiation by granulocyte-macrophage colony-stimulating factor, stem cell factor, and tumor necrosis factor alpha in vitro from lineage phenotypes-negative c-kit+ murine hematopoietic progenitor cells

To elucidate the capacity of murine early hematopoietic progenitor cells (HPCs) to differentiate into dendritic cells (DCs), lineage phenotypes (Lin)-c-kit+ HPCs were highly purified from either wild-type or tumor necrosis factor (TNF) receptor p55 (TNF-Rp55)-deficient mice. Upon culture with granulocyte-macrophage colony-stimulating factor (GM-CSF) and stem cell factor (SCF) for 14 days, wild-type mouse Lin-c-kit+ HPCs did not exhibit characteristic features of DC such as sheet-like projections and veil processes. Moreover, these cells expressed a marginal level of DC markers such as DEC-205, CD86, and barely supported allogenic MLR. However, the addition of mouse TNFalpha generated a large number of cells with typical DC morphology, expression of high levels of Ia, DEC-205, CD86, and function of stimulating allogenic MLR. Moreover, a proportion of these mature DCs and thymic DCs expressed Thy-1 mRNA as well as Thy-1 antigen, whereas freshly isolated splenic DCs did not. These results suggested that DCs generated in our culture system phenotypically resemble thymic ones. In contrast, mouse TNFalpha failed to induce TNF-Rp55-deficient mice-derived Lin-c-kit+ HPCs to generate DCs with characteristic morphology, immunophenotype, and accessory function for T cells under the same culture conditions, suggesting a crucial role of TNF-Rp55 in TNFalpha-mediated DC differentiation from HPCs. Interestingly, human TNFalpha, which can bind to mouse TNF-Rp55 but not TNF-Rp75, was incapable to augment DC generation from wild-type mouse Lin-c-kit+ HPCs. Collectively, these results suggest that TNFalpha has a pivotal role in DC generation from murine early HPCs in collaboration with GM-CSF and SCF through the interaction of TNF-Rp55 and TNF-Rp75.

Effectiveness of fructose-modified chitosan as a scaffold for hepatocyte attachment

Free amino groups of chitosan, a substance which has previously been shown to be a good scaffold for hepatocyte attachment, were covalently modified with fructose. The modification significantly increased the number of cells that could be attached on the surface of chitosan gel. Rat hepatocytes cultivated on fructose-chitosan behaved similarly to those on unmodified chitosan, i.e., they retained the spherical shape they have in vivo, and released much less lactate dehydrogenase than cells attached on a collagen-coated surface. The modification with fructose did not alter the important characteristics of chitosan for hepatocyte culture: liver-specific functions such as urea synthesis and drug metabolism were stably maintained for 5 d in the hepatocytes cultured on fructose-chitosan. In sharp contrast, hepatocytes attached on a collagen-coated surface underwent a severe morphological change, from spherical to flat, and lost almost all their lidocaine-removal activity within 5d. A very thin fructose-chitosan layer was also applied onto the collagen-coated surfaces of polystyrene plates and a dextran microcarrier by crosslinking free amino groups in the chitosan and collagen with glutaraldehyde to fix the thin layer. Hepatocytes on the fructose-chitosan-coated surface retained their spherical shape, masking the cell-flattening effect of the collagen layer. Perfusion culture was then carried out using a hollow-fiber cartridge in which hepatocytes attached on fructose-chitosan-coated microcarriers were suspended in the extracapillary space: the liver-specific functions were stably maintained during 4d of the culture. A fructose-chitosan-coated surface thus appears to be a very promising scaffold for hepatocyte attachment which can be used in cellular biological studies of liver functions, especially in relation to cytochrome P450, as well as in bioartificial liver support systems.

Structures and magnetic properties of dimeric copper(II) benzoylformates. Erratum

The diagram which appeared as Fig. 3 on p. 660 was incorrect [Harada, Tsuchimoto, Ohba, Iwasawa and Tokii (1997). Acta Cryst. B53, 654–661]. The correct figure is shown below.

Structural characterization of mouse monoclonal antibody 13-1 against a porphyrin derivative: identification of a disulfide bond in CDR-H3 of Mab 13-1

The amino acid sequence of a mouse monoclonal antibody Mab13-1, a catalytic antibody against TCPP (meso-tetrakis(4-carboxyphenyl)porphyrin), was confirmed by mass spectrometric (MS) peptide mapping. The amino-terminal sequence of the heavy chain was established by MS/MS analysis of the isolated N-terminal peptide. The presence of a unique disulfide bond between Cys93H and Cys102H was identified by MS peptide mapping and sequence analysis of an S-S containing peptide. Positions of other disulfide bonds were identified to be conserved. The non-conserved disulfide bridge was found to be resistant as other intra-chain disulfide bonds against reduction under non-denaturing condition, and to be buried inside the molecule. This extra disulfide bond is expected to support antigen-binding by restricting the flexibility of CDR-H3 loop, and it might be favorable for the recognition of a plane antigen, a porphyrin derivative.

Effect of thromboxane A2 antagonists on bronchial hyperresponsiveness induced immediately after interleukin-8 inhalation in guinea-pigs

1. Although repeated intranasal administration of interleukin-8 (IL-8) causes bronchial hyperresponsiveness (BHR) mediated via thromboxane A2 (TXA2) and airway neutrophil accumulation in guinea-pigs, the acute effect of inhaled IL-8 is unclear. We performed this study to clarify the acute effect of IL-8 on bronchial responsiveness and the role of TXA2. 2. The effects of inhaled IL-8 on bronchial responsiveness and of the TXA2 antagonists, S-1452 (0.01 and 0.1 mg kg-1) and ONO-NT-126 (1.0 or 10 micrograms kg-1), on IL-8-induced BHR were examined by use of a modified Konzett-Rössler method in guinea-pigs. 3. Inhaled IL-8 at 100 ng ml-1, which failed to induce significant changes in Pao (pressure at the airway opening), enhanced an increase in Pao induced by subsequent inhalations of ascending doses (50-200 micrograms ml-1) of methacholine and histamine, suggesting the potentiating effect of IL-8 on bronchial responsiveness. No significant leukocyte infiltration was observed histologically sixteen minutes after the IL-8 inhalation. Both S-1452 and ONO-NT-126 reduced the IL-8-induced BHR. 4. In conclusion, IL-8 rapidly causes BHR via TXA2 release in guinea-pigs.