Inhibition of angiogenesis by antibody blocking the action of proangiogenic high-molecular-weight kininogen

Previously we demonstrated that domain 5 (D5) of high-molecular-weight kininogen (HK) inhibits neovascularization in the chicken chorioallantoic membrane (CAM) assay and further found that kallikrein cleaved HK (HKa) inhibited FGF2-and VEGF-induced neovascularization, and thus was antiangiogenic. In this study, we sought to demonstrate whether uncleaved HK stimulates neovascularization and thus is proangiogenic. The chick chorioallantoic membrane was used as an in ovo assay of angiogenesis. Low-molecular-weight kininogen stimulates angiogenesis, indicating that D5 is not involved. Bradykinin stimulates neovascularization equally to HK and LK and is likely to be responsible for the effect of HK. A murine monoclonal antibody to HK (C11C1) also recognizes a similar component in chicken plasma as detected by surface plasmon resonance. Angiogenesis induced by FGF2 and VEGF is inhibited by this monoclonal antibody and is a more potent inhibitor of neovascularization induced by VEGF than an integrin alphavbeta3 antibody (LM 609). Our postulate that C11C1 inhibits the stimulation of angiogenesis by HK was confirmed when either C11C1 or D5 completely inhibited angiogenesis in the CAM induced by HK. Growth of human fibrosarcoma (HT-1080) on the CAM was inhibited by GST-D5 and C11C1. These results indicate HK is proangiogenic probably by releasing bradykinin and that a monoclonal antibody directed to HK could serve as an antiangiogenic agent with a potential for inhibiting tumor angiogenesis and other angiogenesis-mediated disorders.

Prognostic value of vascular endothelial growth factor in Stage IB carcinoma of the uterine cervix

PURPOSE

To clarify the role of vascular endothelial growth factor (VEGF) expression as an independent prognostic factor in Stage IB cervical cancer.

METHODS AND MATERIALS

A total of 117 patients with Stage IB cervical cancer who had undergone radical hysterectomy and pelvic lymph node dissection with complete histopathologic examination were included. Eighty-eight (75.2%) patients received postoperative radiotherapy and/or chemotherapy. VEGF expression was examined using immunohistochemistry.

RESULTS

Of 117 patients, 35 (29.9%) showed high-intensity VEGF expression and 69 (59%) had a high score for area of VEGF expression. Strong correlations were found between high VEGF intensity and both deep stromal invasion (p = 0.01) and positive pelvic lymph nodes (p = 0.03). The area of VEGF expression was significantly associated with tumor size (p = 0.02). In a multivariate analysis, high VEGF intensity (p = 0.009) and tumor size (p = 0.01) were significant prognostic factors for overall survival and disease-free survival (p = 0.001 and p = 0.003, respectively). However, the area of VEGF expression was not a prognostic factor for overall survival or disease-free survival.

CONCLUSION

Our findings on the correlation between VEGF expression and prognosis were conflicting. Functional and quantitative tools to assess tumor angiogenesis in addition to the expression of VEGF need to be developed and would be helpful to support the finding that tumor angiogenesis correlates significantly with prognosis in early-stage cervical cancer.

Relation of airway reactivity and sensitivity with bronchial pathology in asthma

Airway hyperresponsiveness in asthmatics, which may result from inflammation or remodeling, is expressed as the concentration of methacholine that causes a 20% fall in FEV1 in the concentration-response curve (PC20). A decrease in PC20 may be due to a steeper curve (hyperreactivity) and/or a curve shift to the left (hypersensitivity). Our purpose was to analyze the relation of airway sensitivity and reactivity to airway pathological changes. The PC6, as sensitivity parameter, and the slope between PC20 and PC40 as reactivity parameter, were calculated. Total and differential cell counts in the bronchoalveolar lavage fluid, and percentage of epithelial shedding, basement membrane thickness, and submucosal thickness on bronchial biopsy, were measured. The PC6 showed a correlation with the baseline FEV1%. The slope was significantly correlated with the basement membrane thickness, and also demonstrated a strong association with submucosal thickness. The PC20 showed a correlation with the baseline FEV1% and the degree of epithelial shedding. These results suggest that the airway sensitivity and reactivity measurements reflect the degree of airway caliber and remodeling, respectively.

Gamma-interferon and soluble interleukin 2 receptor in tuberculous pleural effusion

To analysis the difference between systemic and local pleural T cell response in pulmonary tuberculosis, we analyzed interferon (IFN)-gamma and soluble interleukin-2 receptor (sIL-2R) in peripheral blood mononuclear cells (PBMC) culture supernatants and in pleural effusion (PE). We also investigated the association of pleural INF-gamma and sIL-2R levels with development of residual pleural thickening (RPT). The subjects in this study included patients with active pulmonary tuberculosis with or without PE (n = 46), those with nontuberculous PE (n = 32), and healthy tuberculin reactors (n = 20). Measurement of IFN-gamma and sIL-2R were made by ELISA. In pulmonary tuberculosis, IFN-gamma and sIL-2R concentrations in PBMC culture supernatants were lower than those of healthy tuberculin reactors (IFN-gamma; 258.4 +/-111.5 pg/mL versus 2792.5 +/-633.2 pg/mL, sIL-2R; 1465.0 +/-144.4 pg/mL versus 4777.1 +/-178.5 pg/mL, p < 0.05), whereas IFN-gamma and sIL-2R concentrations in PE were higher than those from nontuberculous pleural effusion (IFN-gamma; 1154.4 +/-252.4 pg/mL versus 292.0 +/-68.9 pg/mL, sIL-2R; 9805.2 +/-978.9 pg/mL versus 3426.7 +/-695.6 g/mL, p < 0.05). IFN-gamma and sIL-2R in PBMC culture supernatants were significantly lower in tuberculat patients with PE than those without PE, and the patients with a high value of IFN-gamma or sIL-2R in PE showed a low value of IFN-gamma or sIL-2R in PBMC culture supernatant, respectively. Patients with RPT had significantly higher IFN-gamma and sIL-2R values in their PE compared with those without RPT. These findings suggest that diminished systemic Th1 response in tuberculosis results from the accumulation of activated Th1 cell to the disease site, and that levels of IFN-gamma and sIL-2R in PE are useful posttreatment markers of RPT.

Observation of a (6)(LambdaLambda)He double hypernucleus

A double-hyperfragment event has been found in a hybrid-emulsion experiment. It is identified uniquely as the sequential decay of ( 6)(LambdaLambda)He emitted from a Xi(-) hyperon nuclear capture at rest. The mass of ( 6)(LambdaLambda)He and the Lambda-Lambda interaction energy DeltaB(LambdaLambda) have been measured for the first time devoid of the ambiguities due to the possibilities of excited states. The value of DeltaB(LambdaLambda) is 1.01+/-0.20(+0.18)(-0.11) MeV. This demonstrates that the Lambda-Lambda interaction is weakly attractive.

Mucin secretion in the rat tracheal epithelial cells by epidermal growth factor and Pseudomonas aeruginosa extracts

BACKGROUND

Hypersecretion of mucin due to goblet cell hyperplasia is frequently encountered in many chronic airway diseases, such as chronic bronchitis, bronchiectasis, bronchial asthma and cystic fibrosis. Even in normal individuals, viral infection or bacterial pneumonia frequently provoke huge amounts of bronchial secretions which may cause airway obstruction. The production of mucin was regulated by epidermal growth factor (EGF) in vitro. To know whether this EGF system regulates mucin secretion in vivo and Pseudomonas also stimulates the mucin secretion by the same pathway, we studied these relationships in the cultured rat tracheal epithelial cells.

METHODS

Rat tracheal epithelial cells were obtained by pronase dissociation from the male Fisher 344 rats. When cells became confluent, they were divided into 6 groups and stimulated with either EGF for 24 hours or Pseudomonas extracts for 12 hours with or without selective EGF-R tyrosine kinase inhibitor tyrphostin AG1478.

RESULTS

We found that both EGF and Pseudomonas extracts phosphorylated the tyrosine residue in the EGF receptor from the rat tracheal epithelial cells and this tyrosine phosphorylation was nearly completely blocked by selective EGF-R tyrosine kinase inhibitor tyrphostin AG1478. The mucin secretion was also stimulated by either EGF or Pseudomonas extracts but more strong secretion of mucin and MUC5AC gene expression in the rat tracheal epithelial cell was done by Pseudomonas extracts.

CONCLUSION

These data suggest that Pseudomonas secretes the mucin by way of the EGF receptor and MUC5AC gene expression and the inhibitors of EGF receptor tyrosine phosphorylation would be useful to prevent the huge production of mucin due to Pseudomonas aeruginosa lung infection.

The usefulness of serum transferrin receptor and ferritin for assessing anemia in rheumatoid arthritis: comparison with bone marrow iron study

OBJECTIVES

This study was aimed at investigating the usefulness of serum transferrin receptor (sTfR) and ferritin in anemic patients with rheumatoid arthritis (RA) compared with bone marrow storage iron and other tests for anemia.

METHODS

Fifty-five anemic RA patients underwent anemia study. Bone marrow iron stain was performed in 18 patients. sTfR and serum ferritin levels were compared with bone marrow iron stores.

RESULTS

(1) Mean sTfR concentration was 2.63+/-1.91 mg/L, (2) sTfR correlated with most indicators of anemia, (3) sTfR showed no correlation with CRP and ESR, whereas ferritin did, and (4) sTfR was higher in the "iron depleted" subgroup than in the "iron nondepleted" subgroup in bone marrow study.

CONCLUSION

The measurement of sTfR and ferritin is useful in finding the cause of anemia in RA and is a possible substitute for invasive bone marrow iron study.

Occupational asthma due to formaldehyde

Formaldehyde is a low molecular weight chemical and can elicit acute and chronic health related problems. Most of the inhaled formaldehyde is retained in the upper respiratory tract due to its extraordinary solubility. Therefore, cases of formaldehyde-induced occupational asthma are sporadic despite its widespread use in industrial processes. We herein report upon a case of occupational asthma due to formaldehyde, which was confirmed by workplace challenge including working environmental assessments, and by formaldehyde inhalation challenge using a specially designed closed-circuit apparatus. To investigate the possible involvement of an IgE-mediated mechanism, both in vitro and in vivo tests were done. IgE antibody specific for formaldehyde-human serum albumin conjugate (F-HSA) was not detected by ELISA, and no specific cutaneous reactivity to F-HSA was noted by either skin prick or intradermal test. The patient was diagnosed with formaldehyde-induced occupational asthma not associated with an IgE mediated mechanism.

Distribution and cytokine production of CD4 and CD8 T-lymphocyte subsets in patients with acute asthma attacks

BACKGROUND

The activation of T cells and the elevation of Th2-type cytokines have been observed in asthmatic patients, but the relative role of CD4 and CD8 T cell is still unclear.

OBJECTIVE

To investigate the role of T cell subset in patients with acute asthma attacks, we analyzed the distribution, activation status, and cytokine production of CD4 and CD8 cells.

METHODS

The percentages of the CD4 and CD8 cell in peripheral blood (PB) and bronchoalveolar lavage (BAL) fluid were analyzed by flow cytometry. The cytokines (IL-4, IL-5, and IFN-gamma) and soluble IL-2 receptor (sIL-2R) were measured by ELISA in culture supernatants of CD4 and CD8 cells purified from PB.

RESULTS

The CD4/CD8 ratio in PB of asthmatic patients was significantly higher than that of controls, which was significantly reduced after treatment. In contrast, there was a tendency to high percentage of CD8 cells in asthmatic patients as compared with controls in BAL, which resulted in a decreased CD4/CD8 ratio. Comparing the T cell subsets in BAL with paired PB in asthma, the CD4 cells were higher in PB, but CD8 cells were higher in BAL. The IL-4, IL-5, and sIL-2R produced by CD4 cells were significantly higher than those produced by CD8 cells in asthmatic patients.

CONCLUSIONS

Our results provide evidence that activated CD4 T cells increase and produce type 2 cytokines in PB, but CD8 T cell are more sequestrated than CD4 T cells in the airway during an acute asthma attack.

Lead treatment in vitro at early developmental stage of bone marrow-derived macrophages enhances NO production through IL-1beta and IL-6 but not TNF-alpha

Lead (Pb(2+)) is known to decrease or block nitric oxide (NO) production by mature macrophages (mphi). Bone marrow cells were treated with various doses of lead in vitro and the morphological and functional changes were observed. Bone marrow cells were treated with various doses of lead (1, 10, 20 and 50 microM) at the start of culture with mphi growth factor (CSF-1), and after 6-7 days of culture, the resultant mphi (bone marrow-derived mphi, BMDM) showed decreased NO production. Unexpectedly, BMDM from the lowest does of lead treatment (1.0 microM) showed increased NO production. The increased NO production was due to increased expression of the iNOS gene and concurrent enhanced transcript levels of proinflammatory cytokines such as IL-1beta and IL-6, but not TNF-alpha. Lead treatment on mature BMDM showed decreased NO production in a dose-dependent manner. These results suggest that a low dose of lead affects developmental characteristics of BMDM through different proinflammatory cytokines, and the lead effects on precursor cells of mphi and mature mphi are different.

Possibility of reciprocal infection of methicillin-resistant Staphylococcus aureus between medical personnel and patients undergoing middle ear surgery

The incidence of methicillin-resistant Staphylococcus aureus (MRSA) infection after middle ear surgery has recently increased in our hospital. In this study we tried to determine whether the strains of MRSA isolated from infected patients are identical to those obtained from medical personnel, to prove a reciprocal transmission between medical personnel and patients. Surveillance bacterial cultures of medical personnel were performed from the anterior nares and from the fingertip. Molecular epidemiological studies, ribotyping and pulsed-field gel electrophoresis (PFGE) were used to compare the 12 MRSA strains obtained from carriers among medical personnel with the 60 strains identified from patient's otorrhea. Six different MRSA strains were identified from ribotyping, and three subtypes from PFGE. There was a particular subtype which was the most frequently identified strain found in both medical carriers and patients. Postoperative MRSA infection rates after the treatment of medical carriers and application of preventive procedures decreased from 11.9 to 5.7%. These findings suggest that the MRSA transmissions have occurred between medical personnel and patients.

Clinical effects of pranlukast, an oral leukotriene receptor antagonist, in mild-to-moderate asthma: a 4 week randomized multicentre controlled trial

OBJECTIVE

Leukotriene antagonists are increasingly used in asthma management. Pranlukast is a new, orally active, selective inhibitor of CysLt1 leukotriene receptor. The present clinical trial was performed to study the effect and safety of pranlukast in mild-to-moderate asthma.

METHODOLOGY

A randomized, double-blind, placebo-controlled, parallel group study was performed in eight medical centres in Korea. Mild-to-moderate asthma patients who had been treated with beta2-agonists and/or inhaled corticosteroids were studied. The patients' symptoms were evaluated by asthma diary and twice-daily peak flow monitoring.

RESULTS

Of the 206 patients enrolled, 197 were eligible for analysis. The pranlukast group (n = 98) showed statistically significant improvement in asthma symptoms, including asthma attack rate, daily living score, and morning and evening asthma scores. Pranlukast significantly reduced the consumption of beta2-agonist. Compared with the placebo group, forced vital capacity (FVC) and forced expiratory volume in 1 s (FEV1) were not significantly higher in the pranlukast group. Morning and evening peak expiratory flow (PEF) were significantly increased after pranlukast treatment at weeks 2 and 4 (380.8 +/- 10.1 L/min at baseline, 394.5 +/- 10.1 at week 2, 396.3 +/- 10.4 at week 4). There were no serious adverse reactions.

CONCLUSION

Pranlukast, an oral leukotriene antagonist, was well tolerated and was effective for the management of mild-to-moderate asthma.

A case of hypothermia combined with systemic lupus erythematosus

Systemic lupus erythematosus(SLE) is a prototypic autoimmune disease affecting various organ systems. Hypothermia is a rare manifestation of SLE. We experienced a case of SLE combined with hypothermia. A 36-year-old woman, who had been diagnosed as SLE 3 days before admission, admitted complaining of mental confusion. After admission, her body temperature, initially 36.1 degrees C, became 32.6 degrees C. Her core body temperature was less than 35.0 degrees C. Despite of warming with heating lamp and blankets, her core temperature did not reach 35.0 degrees C during 18 hours. Ten days later, her temperature exceeded 36.0 degrees C.

A case of basal cell carcinoma of the skin in a patient with systemic sclerosis

A 46-year-old man complained of pain and stiffness in both hands. Most of his fingertips were shortened, and Raynaud's phenomenon was evident. The skin on his face and hands was hard and taut. An ulcerating mass measuring 3.2 x 2.5 cm was found on his left infraorbital area. Biopsy revealed basal cell carcinoma. Antinuclear antibody and anti-topoisomerase I antibody were strongly positive. A high-resolution computed tomography (CT) scan of the lungs revealed interstitial fibrosis. Esophageal manometry showed low lower esophageal sphincter pressure and gastroesophageal reflux. Under the diagnosis of basal cell carcinoma accompanying systemic sclerosis (SSc), surgical excision of the mass was performed, and immunosuppressant and vasodilator therapies were conducted.

A phase II study of a daily x4 schedule of vinorelbine plus cisplatin for advanced non-small cell lung cancer

BACKGROUND

Because dose intensity may be important as a determinant response to vinorelbine, we explored the possibility of increasing the dose intensity of vinorelbine on a daily x4 schedule.

METHODS

Between February 1998 and March 1999, 31 patients with previously untreated advanced non-small cell lung cancer were enrolled. Vinorelbine 15 mg/m2 and cisplatin 20 mg/ m2 were administered intravenously daily for 4 days and repeated every 21 days.

RESULTS

A total 96 cycles were administered (median 3, range 1-6); 42% of vinorelbine and 39% of cisplatin injections were dose-reduced or delayed owing to toxicity. The actual dose intensity (DI) of vinorelbine was 17.7 mg/m2/week and that of cisplatin was 24 mg/m2/week. These figures represent 88 and 90% of the theoretical DI, respectively. The overall response rate was 40% (12/30, one CR). The main toxicity was myelosuppression: granulocytopenia WHO grade 3 and 4 in 24 patients (77%) and thrombocytopenia grade 3 in two patients (6%). The non-hematological toxicity was mild and tolerable. After a median follow-up of 7.5 months (range 3-21 months), the median progression-free survival and overall survival times were 5 months (95% CI, 3.8-6.2) and 8 months (95% CI, 4.5-11.5), respectively.

CONCLUSIONS

This regimen has a comparable therapeutic activity in patients with advanced lung cancers. However, despite supportive care there were excessive hematological toxicities. In view of increased toxicity and similar efficacy, this regimen is not indicated outside a clinical trial.

Characteristics of lung cancer in Korea, 1997

The high proportion of smokers and the incidence of advanced, unresectable lung cancer in Korea were examined to aid the development of a national anti-smoking program and the early detection of lung cancer. Koreans are a single racial group with a high smoking rate among men and a contrastingly low smoking rate among women. This report documents a retrospective investigation conducted by The Korean Academy of Tuberculosis and Respiratory Disease into the characteristics of all lung cancers diagnosed between 1 January 1997 and 31 December 1997 in Korea. Among the 3794 patients included in this study, 76.8% were smokers and, in particular, 89.8% of the males were smokers. Squamous cell carcinoma was the most frequent type of lung cancer encountered (44.7%), followed by adenocarcinoma (27.9%). The smoking rate in the case of adenocarcinoma was significantly lower than that found in both squamous cell carcinoma and small cell cancer. The most common symptom was a cough. Only 7.2% of patients were asymptomatic. Bronchoscopic biopsy has a primary role in the diagnosis of squamous cell carcinoma and small cell cancer, but percutaneous needle biopsy has a more important role in the case of adenocarcinoma. Two-thirds of the nonsmall cell lung cancer patients were detected in the unresectable advanced stages (IIIB and IV). In contrast to other countries, squamous cell carcinoma is still the most frequent type of lung cancer in Korea. The high proportion of smokers and the incidence of advanced, unresectable lung cancer at diagnosis have urged development of a national anti-smoking program to promote the cessation of smoking and the early detection of lung cancer.

Long-term results of laser in situ keratomileusis for high myopia

The objective of this study was to evaluate the results of laser in situ keratomileusis (LASIK) for high myopia after a follow-up of two years. A total of 42 eyes from 33 patients with high myopia (range: -9.00 D to -25.50 D) were studied. LASIK was performed using an automated microkeratome (Steinway, USA) and OmniMed II excimer laser with the standard MKM program (Summit Technology, Inc., Waltham, MA) in all patients. The patients were followed up at one, three, six, 12 and 24 months. During follow-up manifest refraction and best corrected and uncorrected visual acuity were measured. Any complications were also analyzed. The two-year follow-up results were as follows. The mean postoperative manifest spherical equivalents (MSE) were -0.51 D at one month, -1.09 D at three months, -1.78 D at six months, -2.17 D at 12 months and -2.61 D at 24 months. Myopic regression continued during the two-year follow-up (p < 0.05). The accuracy of the intended postoperative correction within +/- 2.00 D was 73.8% at one month, 69.1% at three months, 52.4% at six months, 52.4% at 12 months, and 45.2% at 24 months. The best corrected visual acuity (BCVA) was unchanged or increased in 35 eyes (83.3%). Only three eyes (7.2%) lost two or more lines of BCVA. This was due to irregular astigmatism in one eye, macular degeneration in one eye, and rhegmatogenous retinal detachment in one eye. In this study, LASIK was effective and safe in the correction of high myopia, however continuous myopic regression was seen over the two-year follow-up. Refining the nomogram to adjust for progressive myopic regression will be necessary in order to obtain better results.

Effect of temperature on the breakthrough of a charcoal tube during vinyl chloride monomer sampling

This study evaluated the effects of temperature on breakthrough of two standard collection media at various concentrations during vinyl chloride monomer (VCM) sampling. The National Institute for Occupational Safety and Health (NIOSH) and Occupational Safety and Health Administration (OSHA) methods were evaluated. To determine whether breakthrough of VCM would occur at the extremes of exposure and temperature that might be encountered in some workplaces, air samples containing 4 ppm (10.24 mg/m3), 8 ppm (20.45 mg/m3), 16 ppm (40.98 mg/m3), and 32 ppm (81.80 mg/m3) of VCM were collected at temperatures of 4, 22, and 40 degrees C. Five liters of air was sampled at the rate of 0.05 L/min for 100 min using the activated charcoal tube recommended by NIOSH. A second tube was added to the sampling train to collect any VCM that might not have been absorbed in the first tube. To collect VCM air samples by the OSHA method, two carbon molecular sieve tubes were connected serially and 3 L of air was sampled at the rate of 0.05 L/min for 60 min. A gas chromatograph with a flame ionization detector and ultra 2 capillary column was used to analyze VCM. Significant breakthrough was found when sampling at higher temperatures with the NIOSH method. No breakthrough was found when samples were collected using the OSHA media at different temperatures and concentrations. Therefore, under hot ambient conditions (>22 degrees C), the possibility of breakthrough should be considered when sampling VCM by the NIOSH method.

Pulmonary fibrosis in a steel mill worker

We report a case of pulmonary fibrosis in a 32-year-old man, who had worked at a steel mill and who died of respiratory failure due to interstitial fibrosis despite vigorous treatment. He showed SLE-associated symptoms, such as pleural effusion, malar rashes, discoid rashes, arthritis, leukopenia, and positive antinuclear antibody and anti-histone antibody. However, he did not present anti-DNA antibody. A thoracoscopic lung biopsy showed interstitial fibrosis, chronic inflammation and a small non-caseating granuloma in lung tissues, which could be induced by external agents such as metals. The manganese concentration in the lung tissue was 4.64 microg/g compared to 0.42-0.7 microg/g in the controls. The levels of other metals, such as iron, nickel, cobalt and zinc in patient's lung tissue were higher than those in the controls. The patient was probably exposed to Si and various metal dusts, and the lung fibrosis was related to these exposures. Exposure to Si and metal dusts should be sought in the history of any patient with SLE, especially in a male with pulmonary signs, and if present, exposure should be stopped. In the meantime, steps should be taken to ensure that workers exposure to Si and metal dusts in all environments have adequate protection.

Tyrosine phosphorylation of Vav stimulates IL-6 production in mast cells by a Rac/c-Jun N-terminal kinase-dependent pathway

This study investigates whether the guanine nucleotide exchange activity of Vav is linked to cytokine production in mast cells. Overexpression of Vav in the RBL-2H3 mast cell line resulted in the constitutive tyrosine phosphorylation and activation of Vav. We analyzed the functional effect of Vav overexpression on cytokine production. IL-2 and IL-6 mRNA levels were dramatically increased in Vav-overexpressing cells and correlated with increased NF-AT activity. Little or no effect was observed on the mRNA levels of IL-3, IL-4, GM-CSF, TNF-alpha, and TGF-beta. FcepsilonRI engagement did not further enhance IL-2 and IL-6 mRNA levels and only slightly enhanced NF-AT activity, but dramatically increased the mRNA levels of other tested cytokines. To understand the signal transduction required, we focused primarily on IL-6 induction by measuring mitogen-activated protein kinase activity and analyzing the effects of mutant or dominant negative forms of Vav, Rac1, and c-Jun N-terminal kinase-1 (JNK1). Vav overexpression resulted in the constitutive activation of JNK1 with little or no effect on p38 mitogen-activated protein kinase and ERK2. This was dependent on Vav-mediated activation of Rac1 as a Dbl domain-mutated Vav, inactive Rac N17, and inactive JNK1 down-regulated the Vav-induced JNK1 or IL-6 responses. Vav expression, but not expression of domain-mutated Vav, increased IL-6 secretion from nonimmortalized bone marrow-derived mast cells upon FcepsilonRI engagement. We conclude that Vav phosphorylation contributes to IL-6 induction in mast cells.

Expression of ICAM-1 on the Hantaan virus-infected human umbilical vein endothelial cells

OBJECTIVES

In HFRS, there is a varying degree of disseminated intravascular coagulation which was evident in the early phase of the illness. It is believed also that DIC would be the consequence, at least in part, of functional changes of endothelium resulting in kinin activation and clinical syndrome. This study investigated the role of adhesion molecule in the pathogenesis of Hantaan virus-related disease.

METHODS

The expression of ICAM-1 antigen on the cell membrane of human umbilical vein endothelial cells was assessed by immunohistochemistry, and ICAM-1 mRNA in the endothelial cells was assessed by in situ hybridization after Hantaan virus infection (2.6 x 10(4) PFU/mL) with the time course.

RESULTS

In immunohistochemistry, the number of ICAM-1 positive cells increased with time during the 12 or 24 hours after infection. 5 to 10% of HUVECs had been positive after 12-24 hours and the number of positive cells decreased abruptly after 24 hours. Hantaan antigen had been noticed after 12 hours focally on the HUVECs but continued to proliferate into day 7 post-infection when most of HUVECs were infected by Hantaan virus. In situ hybridization showed identical patterns of ICAM-1 mRNA expression after Hantaan virus infection.

CONCLUSION

It implies that the Hantaan virus infection on HUVECs would express more ICAM-1 on their surface and implicated in the pathogenesis of early clinical syndrome of HFRS.

Polyethylene glycol-mediated infection of non-permissive mammalian cells with semliki forest virus: application to signal transduction studies

Semliki Forest Virus (SFV) vectors allow the subcloning of a gene of interest directly in the expression vector, thus avoiding the need to select and purify viral recombinants, making this viral expression system attractive over many others for mammalian protein expression. We now describe a novel and generally applicable method for infection of non-permissive mammalian cells with SFV, that greatly enhances the utility of this expression system. We demonstrate that the hygroscopic polymer poly (ethylene glycol), PEG, promotes the infectivity of cells by SFV under conditions that did not promote cell-cell fusion. We also found that the PEG-induced infection and expression of an exogenous protein (green fluorescent protein, GFP) did not elevate the basal tyrosine kinase activity, induce a stress-activated responses, or result in aberrant cell responses. Expression of GFP tagged-Vav, an activator of stress-activated protein kinase (SAPK/JNK), resulted in the expected induction of JNK activity and in the normal redistribution of Vav in response to engagement of the high affinity receptor for IgE (FcepsilonRI). Thus, our findings that PEG allows the infection of non-permissive cells by SFV makes this system extremely attractive for expression of proteins in mammalian cells, and studies on signal transduction and cellular localization in immune and non-immune cells.

Streptococcal keratitis after myopic laser in situ keratomileusis

A 24-year-old healthy male underwent uncomplicated laser in situ keratomileusis (LASIK) in left eye. One day after the surgery, he complained of ocular pain and multiple corneal stromal infiltrates had developed in left eye. Immediately, the corneal interface and stromal bed were cleared, and maximal antibiotic treatments with fortified tobramycin (1.2%) and cefazolin (5%) were given topically. The causative organism was identified as 'Streptococcus viridans' both on smear and culture. Two days after antibiotic therapy was initiated, the ocular inflammation and corneal infiltrates had regressed and ocular pain was relieved. One month later, the patient's best corrected visual acuity had returned to 20/20 with -0.75 -1.00 x 10 degrees, however minimal stromal scarring still remained. This case demonstrates that microbial keratitis after LASIK, if treated promptly, does not lead to a permanent reduction in visual acuity.

A molecular epidemiologic study of methicillin-resistant Staphylococcus aureus infection in patients undergoing middle ear surgery

The incidence of methicillin-resistant Staphylococcus aureus (MRSA) infections after middle ear surgery has recently increased at our hospital. Most of these infections were thought to be hospital-acquired when medical personnel in contact with an MRSA-infected patient may have inadvertently transmitted the pathogen to other patients. To prevent further transmission it is essential that such sources of MRSA infection and transmission routes be selected out and eradicated. Therefore, it is necessary to determine whether the strains of MRSA isolated from infected patients are identical to those obtained from medical personnel in order to prove a reciprocal transmission of organisms between medical personnel and patients. Surveillance bacterial cultures from the anterior nares and hands of medical personnel working in the Department of Otolaryngology, Korea University Guro Hospital, were performed at two different time points: 6 December 1994 and 17 June 1996. Ribotyping with Southern blot technique was used to compare 12 MRSA strains from medical carriers with 60 strains identified from the otorrhea of MRSA-infected patients undergoing middle ear surgery. As results, six different MRSA strains were identified (types I, II, III, IV, V and VI) from ribotyping with EcoR1. One distinct subtype, type I strain, was the most frequently identified strain in both medical carriers and patients. Results also showed that 6 MRSA isolates from 10 medical carriers and 20 from 30 patients contained type I ribotype at first culture. Two medical carriers' isolates and 13 isolates from 30 patients shared the same type I strain at the second surveillance culture. In all, 41 out of 72 MRSA strains (56.9%) shared an identical ribotype pattern. Postoperative MRSA infection rates after treatment of medical carriers and the application of rigorous preventive procedures decreased from 11.9 to 5.7% after first culture and 9.0 to 7.7% following second cultures. These findings confirm that MRSA transmission can occur between medical personnel and patients and that effective preventive measures can reduce the postoperative infection rate.

Homology modeling of the receptor binding domain of human thrombopoietin

Platelet production in blood is regulated by a lineage specific humoral factor, thrombopoietin (TPO). The amino terminal domain of TPO (TPO-N) is responsible for the signal transduction mediated by the TPO receptor, c-mpl. From the predicted length of helices we found that TPO-N belongs to the long-chain subfamily of the four-helix bundle cytokine family. We built a three dimensional model of TPO-N by a comparative homology modeling procedure. The four helices of TPO-N with an up-up-down-down topology are stabilized by a tightly packed central hydrophobic core and the extended loop AB makes an additional hydrophobic core with helices B and D outside of the four helix bundle scaffold. An interpretation of the previous site directed mutageneses results in light of the model enabled us to identify two isolated receptor binding sites. The surface made of Lys 136, Lys 138 and Lys 140 in helix D, and Pro 42 and Glu 50 in loop AB forms the first receptor binding site, while the surface of Asp 8, Arg 10 and Lys 14 in helix A represents the second binding site for the sequential receptor oligomerization.