Clinical features and molecular epidemiology of multidrug-resistant Acinetobacter calcoaceticus-A baumannii complex in a regional teaching hospital in Taiwan

We conducted a case-controlled study in a regional teaching hospital in Taiwan to investigate the clinical features and molecular epidemiology of multidrug-resistant Acinetobacter calcoaceticus-A baumannii (MDR Acb) complex. Case patients had higher mortality than controls did. MDR Acb complex acquisition risk factors include longer hospital stays, higher ratio of nasogastric tube and Foley catheter use, and more carbapenem use. All available isolates were divided into 36 subtypes by pulsed-field gel electrophoresis. The proportion of the same subtypes with their appearance within 1 and 2 months was 62.5% and 87.5%, respectively. We concluded that many different MDR Acb complex clones could be found in a hospital and that the same clones often spread on a small scale within a short period of time if no outbreaks noted.

Characterization of antimicrobial resistance patterns and integrons in human fecal Escherichia coli in Taiwan

Two hundred and twenty-five fecal strains of Escherichia coli isolated from 109 non-hospitalized adults in 2006 were investigated for susceptibility to antibiotics and for the presence of integrons. High resistance rates in fecal strains of E. coli were observed for streptomycin (52.0%), ampicillin (50.2%), piperacillin (50.2%), trimethoprim/sulfamethoxazole (47.6%) and chloramphenicol (33.8%). Integrons were found in 31.5% (71/225) of the strains using an integrase gene PCR assay. Among 71 integrase-positive strains, 65 strains belonged to class 1 integrons, while the remainder belonged to class 2. Gene cassette patterns of class 1 integrons were further characterized by PCR and direct sequencing. Among those class 1 integrase-containing isolates, the integron cassette region was amplified by PCR in 40.0% (26 of 65) of isolates. Five different antimicrobial resistance gene cassette arrays were found in those isolates. These gene cassettes included those encoding resistance to trimethoprim (dfrV, dfrA7, dfrA12, dfrA17) and streptomycin (aadA1, aadA2, aadA5). Among those gene cassette arrays, dfrA12-orfF-aadA2 was found in 53.8% (14/26) of the isolates. These findings indicate that multidrug resistance of fecal flora is common in Taiwan and that integrons play an important role in resistance to trimethoprim and streptomycin in humans.

Comparison of antimicrobial resistance patterns between clinical and sewage isolates in a regional hospital in Taiwan

AIMS

To compare bacterial populations and antimicrobial resistance patterns between clinical and sewage isolates from a regional hospital in northern Taiwan. The dissemination of antibiotic-resistant bacteria from hospital compartments to the hospital sewage treatment plant was examined.

METHODS AND RESULTS

A total of 1020 clinical isolates and 435 sewage isolates were collected between July and September 2005. The percentages of Gram-negative bacteria from the clinical and sewage isolates were 87.2% and 91.0%, respectively (P = 0.033). Escherichia coli were the leading bacterial isolates in both groups. Antimicrobial susceptibility testing showed a significant difference (P < 0.001) in resistance to ampicillin (85.6% vs 94.1%), ampicillin/sulbactam (31.7% vs 55.4%), cefazolin (29.2% vs 71.5%) and cefuroxime (20.7% vs 61.9%) between clinical and sewage coliform isolates, respectively.

CONCLUSIONS

The sewage isolates had higher antimicrobial resistance rates than the clinical isolates from the same hospital.

SIGNIFICANCE AND IMPACT OF THE STUDY

The low efficacy of the hospital sewage treatment may contribute to the dissemination of multidrug resistant bacteria from this hospital compartments to the environment. Practices which limit the disposal of antimicrobial agents into the wastewater system may be the possible measure to prevent the selection of multidrug-resistant bacteria from sewage treatment plants.

Effects of Cysteamine on Growth Performance, Digestive Enzyme Activities, and Metabolic Hormones in Broilers

A total of 600 avian male broilers at the age of 1 d were used to investigate the effects of cysteamine (CSH) on growth performance, digestive enzyme activities, and concentrations of serum hormones. The broilers received the same basal diets, with CSH added at 0 (control), 60, 90, 120, or 150 mg/kg. The feeding program consisted of a starter diet until 21 d and a grower diet until 42 d. The broilers with addition of CSH at 60 or 90 mg/kg had significantly higher growth rates during d 1 to 21 or d 21 to 42 compared with the control, respectively. However, adding 150 mg of CSH/kg significantly suppressed the growth of broilers. Adding 60 mg of CSH/kg significantly increased the activities of protease, amylase, and lipase in the pancreas and small intestinal contents during d 1 to 21, and the activities of protease and amylase in the small intestinal contents during d 21 to 42. Adding 90 mg of CSH/kg significantly increased the activities of lipase during d 1 to 21 and protease, amylase, and lipase during d 21 to 42 in small intestines. The activities of digestive enzymes during the whole period were suppressed by adding 150 mg of CSH/kg. The concentration of serum thyroxine was higher in the CSH-added birds during the whole period, whereas serum triiodothyronine was higher only during d 1 to 21 compared with the control. These findings indicate that low doses of dietary CSH may improve the growth performance and the activities of the digestive enzyme, but high doses of CSH appear to be detrimental to growth and digestion.

Intravitreal triamcinolone staining observation of residual undetached cortical vitreous after posterior vitreous detachment

AIMS

To study the pattern of residual undetached cortical vitreous (RCV) after posterior vitreous detachment (PVD) in eyes with rhegmatogenous retinal detachment (RRD) and to examine the relationship between RCV and the development of epiretinal membrane (ERM).

METHODS

A prospective study was conducted in 33 consecutive patients with clinically evident PVD who underwent pars plana vitrectomy for RRD. During vitrectomy, triamcinolone acetonide (0.2 cm(3), 10 mg/cm(3)) was applied to stain the RCV. The pattern of the staining were recorded. The formation of postoperative ERM was correlated with the staining pattern of RCV. Each case was followed for at least 6 months.

RESULTS

In all, 23 of the 33 patients had RCV of variable size, with a single stain patch observed in 13 patients and multiple patches in seven patients. Large circumferential areas of staining at the mid-periphery were noted in three patients. A total of 10 cases had staining over the fovea and five patients had staining over the disc. ERM developed in seven patients during follow-up. None corresponded to RCV.

CONCLUSION

RCV is common in eyes with PVD and RRD. The macula and disc area are the most frequent locations for these vitreous islands. The relationship between RCV and ERM remains to be investigated.

Biodegradation of phthalate esters by two bacteria strains

In this study two aerobic phthalic acid ester (PAE) degrading bacteria strains, DK4 and O18, were isolated from river sediment and petrochemical sludge, respectively. The two strains were found to rapidly degrade PAE with shorter alkyl-chains such diethyl phthalate (DEP), dipropyl phthalate (DPrP), di-n-butyl phthalate (DBP), benzylbutyl phthalate (BBP) and diphenyl phthalate (DPP) are very easily biodegraded, while PAE with longer alkyl-chains such as dicyclohexyl phthalate (DCP) and dihexyl phthalate (DHP) and di-(2-ethylhexyl) phthalate (DEHP) are poorly degraded. The degradation rates of the eight PAEs were higher for strain DK4 than for strain O18. In the simultaneous presence of strains DK4 and O18, the degradation rates of the eight PAEs examined were enhanced. When the eight PAEs were present simultaneously, degradation rates were also enhanced. We also found that PAE degradation was delayed by the addition of nonylphenol or selected polycyclic aromatic hydrocarbons (PAHs) at a concentration of 1 microg/g in the sediment. The bacteria strains isolated, DK4 and O18, were identified as Sphigomonas sp. and Corynebacterium sp., respectively.

Measurements of the cross section for e(+)e(-) --> hadrons at center-of-mass energies from 2 to 5 GeV

We report values of R = sigma(e(+)e(-)-->hadrons)/sigma(e(+)e(-)-->mu(+)mu(-)) for 85 center-of-mass energies between 2 and 5 GeV measured with the upgraded Beijing Spectrometer at the Beijing Electron-Positron Collider.

Estimation of leaf nitrogen content from spectral characteristics of rice canopy

Ground-based remotely sensed reflectance spectra of hyperspectral resolution were monitored during the growing period of rice under various nitrogen application rates. It was found that reflectance spectrum of rice canopy changed in both wavelength and reflectance as the plants developed. Fifteen characteristic wavebands were identified from the apparent peaks and valleys of spectral reflectance curves, in accordance with the results of the first-order differentiation, measured over the growing season of rice. The bandwidths and center wavelengths of these characteristic wavebands were different among nitrogen treatments. The simplified features by connecting these 15 characteristic wavelengths may be considered as spectral signatures of rice canopy, but spectral signatures varied with developmental age and nitrogen application rates. Among these characteristic wavebands, the changes of the wavelength in band 11 showed a positive linear relationship with application rates of nitrogen fertilizer, while it was a negative linear relationship in band 5. Mean reflectance of wavelengths in bands 1, 2, 3, 5, 11, and 15 was significantly correlated with application rates. Reflectance of these six wavelengths changed nonlinearly after transplanting and could be used in combination to distinguish rice plants subjected to different nitrogen application rates. From the correlation analyses, there are a variety of correlation coefficients for spectral reflectance to leaf nitrogen content in the range of 350-2400 nm. Reflectance of most wavelengths exhibited an inverse correlation with leaf nitrogen content, with the largest negative value (r = -0.581) located at about 1376 nm. Changes in reflectance at 1376 nm to leaf nitrogen content during the growing period were closely related and were best fitted to a nonlinear function. This relationship may be used to estimate and to monitor nitrogen content of rice leaves during rice growth. Reflectance of red light minimum and near-infrared peak and leaf nitrogen content were correlated nonlinearly.

Seasonal changes of chlorophyll content in field-grown rice crops and their relationships with growth

Field experiments were conducted on the experimental farm of the Taiwan Agricultural Research Institute (TARI) to examine seasonal changes in the amounts of chlorophylls in leaves and whole plants of rice (Oryza sativa L. cv. Tainung 67) grown in the first and the second crop seasons in 1998. Chlorophyll (Chl) differences between two crops and their relationships with growth were also investigated. The differences in climate conditions between the two crop seasons were quite phenomenal and led to different rates of plant growth and amounts of chlorophyll produced during the growth periods. Seasonal changes in Chla, Chlb, and total Chl were curvilinear in style, with Chla making up the major portion of total chlorophyll. Young plants of rice began with lower levels of chlorophyll, which increased as the plants developed, and decreased as the plants aged. A significant increase in chlorophyll occurred in the early stage of the second crop compared to that of the first crop, and the difference was maintained throughout the growing season. When the unit time transformation technique was used to exclude the difference in growth rate, the curves of the chlorophylls (Chla, Chlb, and total ChI) were similar in the two crops, but plants grown in the second crop season had higher levels of chlorophylls at the same time unit scale. Generally, the ratio of Chla to Chlb (Chla/Chlb) decreased after transplanting, indicating a significant reduction (p < 0.01) in the green-to-yellow pigment relationship. Plants grown in the first crop had higher Chla/Chlb ratios than those grown in the second crop, especially in leaf blades. Good agreement was found between growth traits and the respective total Chl cotent from regression analyses, and these growth traits were highly correlated with total Chl (R2 > 0.8). However, rice plants grown in the first crop showed a higher levels of plant growth and leaf area at the same chlorophyll level than those grown in the second crop. These results suggest that rice plants grown in the first crop may exhibit better growth and production than those grown in the second crop under normal growing conditions.

Seroprevalence and demographic characteristics of HTLV-I among blood donors in Taiwan: 1996-1999

Screening for the human T-cell lymphotropic virus type I (HTLV-I) and-II in blood donors was implemented in Taiwan beginning in February 1996. The purpose of the present study was to investigate the changes in HTLV-I seroprevalence in all unpaid blood donors in Taiwan during the period from February 1996 to December 1999 and to determine the influence of age and sex on the HTLV-I seropositivity of donors. HTLV-I and HTLV-II screening was performed using combined HTLV-I/II immunoassay. Repeated reactive samples were confirmed by Western blot analysis. Of a total of 3,701,087 donors in all 6 blood centers in Taiwan, 2,311 (0.058%) were seropositive for HTLV-I. The HTLV-I seropositivity was 0.130%, 0.063%, 0.044%, and 0.032% in the years 1996, 1997,1998, and 1999, respectively. There was a linear increase of HTLV-I seropositivity with advancing age. The HTLV-I carrier rate for female donors was twice that for the male donors. Ninty-seven percent of HTLV-I seropositive results came from first-time donors. Our findings suggest that Taiwan is a low-prevalence nonendemic area for HTLV-I infection. The large-scale HTLV-I screening program has decreased HTLV-I seropositivity among blood donors and is useful for preventing HTLV-I transmission via blood transfusion.

Tumour necrosis factor-alpha enhances bradykinin-induced signal transduction via activation of Ras/Raf/MEK/MAPK in canine tracheal smooth muscle cells

Inhalation of tumour necrosis factor-alpha (TNF-alpha) induced a bronchial hyperreactivity to contractile agonists. However, the mechanisms of TNF-alpha involved in the pathogenesis of bronchial hyperreactivity were not completely understood. Therefore, we investigated the effect of TNF-alpha on bradykinin (BK)-induced inositol phosphate (IP) accumulation and Ca(2+) mobilization, and up-regulation of BK receptor density in canine cultured tracheal smooth muscle cells (TSMCs). Pretreatment of TSMCs with TNF-alpha potentiated BK-induced IP accumulation and Ca(2+) mobilization. However, there was no effect on the IP response induced by endothelin-1 (ET-1), 5-hydroxytryptamine (5-HT), and carbachol. Pretreatment with PDGF B-chain homodimer (PDGF-BB) also enhanced BK-induced IP response. These enhancements induced by TNF-alpha and PDGF-BB might be due to an increase in BK B(2) receptor density (B(max)), since [3H]BK binding to TSMCs was inhibited by the B(2) selective agonist and antagonist, BK and Hoe 140, but not by the B(1) selective reagents. The enhancing effects of TNF-alpha and PDGF-BB were attenuated by PD98059 (an inhibitor of activation of MAPK kinase, MEK) and cycloheximide (an inhibitor of protein synthesis), suggesting that TNF-alpha may share a common signalling pathway with PDGF-BB via protein(s) synthesis in TSMCs. Furthermore, overexpression of dominant negative mutants, H-Ras-15A and Raf-N4, significantly suppressed p42/p44 mitogen-activated protein kinase (MAPK) activation induced by TNF-alpha and PDGF-BB and attenuated the effect of TNF-alpha on BK-induced IP response, indicating that Ras and Raf may be required for activation of these kinases. These results suggest that the augmentation of BK-induced responses produced by TNF-alpha might be, at least in part, mediated through activation of Ras/Raf/MEK/MAPK pathway in TSMCs.

Uncoupling of ATP-induced inositol phosphate formation and Ca(2+) mobilization by phorbol ester in canine cultured tracheal epithelial cells

The regulation of the increase in inositol phosphates (IPs) production and intracellular Ca(2+) concentration ([Ca(2+)](i)) by protein kinase C (PKC) was investigated in canine cultured tracheal epithelial cells (TECs). Pretreatment of TECs with phorbol 12-myristate 13-acetate (PMA, 1 microM) for 30 min attenuated the ATP- and UTP-induced IPs formation and Ca(2+) mobilization. The concentrations of PMA that gave half-maximal (EC(50)) inhibition of ATP- and UTP-induced IPs accumulation and an increase in [Ca(2+)](i) were 5-10 and 4-12 nM, respectively. Prior treatment of TECs with staurosporine (1 microM), a PKC inhibitor, partially inhibited the ability of PMA to attenuate ATP- and UTP-induced responses, suggesting that the inhibitory effect of PMA is mediated through the activation of PKC. Furthermore, analysis of cell extracts by Western blotting with antibodies against different PKC isozymes revealed that TECs expressed PKC-alpha, -betaI, -betaII, -gamma, -delta, -epsilon, -theta, and -zeta. With PMA treatment of the cells for various times, translocation of PKC-alpha, -betaI, -betaII, -gamma, -delta, -epsilon, and -theta from the cytosol to the membrane was seen after 5- and 30-min and 2- and 4-h treatment. However, 6-h treatment caused a partial down-regulation of these PKC isozymes. PKC-zeta was not significantly translocated and down-regulated at any of the times tested. In conclusion, these results suggest that activation of PKC may inhibit the phosphoinositide (PI) hydrolysis and consequently attenuate the [Ca(2+)](i) increase or inhibit independently both responses to ATP and UTP. The translocation of PKC-alpha, -betaI, -betaII, -delta, -epsilon, -gamma, and -theta induced by PMA caused an attenuation of ATP- and UTP-induced IPs accumulation and Ca(2+) mobilization in TECs.

Spectral characteristics of rice plants infested by brown planthoppers

Spectral characteristics of rice plants at various levels of infestation by the brown planthopper, Nilaparvata lugens (Stål), (Homoptera:Delphacidae), in the early grain-filling stage were measured and analyzed using a spectroradiometer. Plant damage was classified into six scales, i.e., 0 (CK), 1, 3, 5, 7 and 9, based on the scale of infestation displayed on the surfaces of plant parts. Results showed that mean curves of reflectance spectra (350 - 1800 nm) from different scales of insect infestation were clearly differentiated, especially in the region of 737 - 925 nm, where reflectance was in the order of severity. There were significant differences in reflectance among infestations at wavelengths of 755 and 890 nm particularly. Spectral parameters such as the normalized difference vegetation index (NDVI) and cumulative reflectance may also be used to discriminate levels of infestation. Twelve wavelengths from apparent peaks and valleys of individual spectra were selected as characteristic wavelengths making up the spectral signature of each infestation.

Acute lupus pneumonitis mimicking pulmonary tuberculosis: a case report

We report a case of systemic lupus erythematosus in a 15-year-old girl with initial presentation as acute lupus pneumonitis. A fulminant course with pancytopenia and respiratory distress were developed 3 weeks after symptom onset. Chest radiographs revealed an interstitial pattern with miliary nodules over bilateral lower lung fields that mimics miliary tuberculosis. The patient was treated with intravenous immunoglobulin and antituberculosis drugs because the infection-associated hemophagocytic syndrome and pulmonary tuberculosis could not be excluded from the clinical course. The response to antituberculosis treatment, however, was poor and her respiratory condition deteriorated rapidly to impending respiratory failure 1 week after admission. Systemic lupus erythematosus with acute lupus pneumonitis was then diagnosed based on the fulminant clinical course and accordant laboratory results. Corticosteroid (methylprednisolone) and cytotoxic agent (cyclophosphamide) pulse therapies were applied twice and once, respectively. She recovered gradually after receiving the immunotherapy.

A single dose of melatonin prevents the phase delay associated with a delayed weekend sleep pattern

STUDY OBJECTIVES

This study was designed to test the hypotheses that a delayed weekend sleep pattern may lead to a phase delay of the endogenous circadian rhythm, and that melatonin administration can counteract the phase delay and prevent the sleep and functional impairments associated with this sleep pattern.

DESIGN

A within-subject, counterbalanced design was used in which each subject participated in both placebo and melatonin conditions. Subjects' sleep-wake schedules were delayed by two hours on Friday and Saturday to simulate the delayed weekend sleep pattern. Six mg of melatonin or a placebo pill was administered double blind on Sunday late afternoon.

SETTING

N/A.

PARTICIPANTS

Ten healthy volunteers (mean age = 22.1 years old).

MEASUREMENTS AND RESULTS

Salivary dim-light melatonin onset (DLMO) was measured on Friday and Monday nights. Subject's sleep was recorded with polysomnography on Sunday night and their levels of sleepiness, cognitive functioning and mood were assessed on Sunday night and Monday morning. Results show that the delayed weekend sleep pattern caused a 31.6 min delay of the endogenous melatonin rhythm. Melatonin administration counteracted the phase delay of endogenous melatonin onset. On Sunday, melatonin administration increased the sleepiness throughout the evening and reduced sleep onset latency at bedtime. On Monday morning, subjective sleepiness was decreased in the melatonin condition.

CONCLUSION

A delayed weekend sleep pattern did show a mild phase-delay effect on the endogenous circadian rhythm. A single dose of melatonin can acutely reverse the weekend drift.

Recurrence of intussusception in childhood

Intussusception is the most common cause of intestinal obstruction between 3 months and 6 years of age. Recurrence after reduction of intussusception in childhood is not rare. To assess the incidence and determinants of recurrence of intussusception in childhood, we conducted a prospective observation in an emergency service of a large referral center during a four-year period. We encountered 89 cases with intussusception of whom nine cases (10.1%) had episodes of recurrent intussusception. Five patients had a single recurrence, three had double recurrence and one had triple recurrence. Age of first intussusception, sex, or concurrent adenovirus infection was not related to the recurrence. None of the 27 patients who needed operative reduction had recurrence, while 9 of 62 patients who were reduced successfully by barium enema developed recurrence (P = 0.05). Compared with the first episode, significantly less vomiting, rectal bleeding and shorter duration of abdominal pain or irritable crying were noted during recurrent episodes. All the recurrent episodes were reduced successfully by barium enema. We conclude that recurrent intussusception in childhood tends to be diagnosed earlier than previous episodes and treated successfully by hydrostatic reduction without complication. Surgical reduction of recurrent intussusception may be reserved for cases of failure of hydrostatic reduction, positive peritoneal sign or existence of pathological lead point because of favorable response to barium reduction. Recurrent intussusception seldom occurs in patients who underwent surgical reduction.

Mechanisms of thrombin-induced MAPK activation associated with cell proliferation in human cultured tracheal smooth muscle cells

The elevated level of thrombin has been detected in the airway fluids of asthmatic patients. However, the implication of thrombin in the pathogenesis of bronchial hyperreactivity was not completely understood. Therefore, in this study we investigated the effect of thrombin on cell proliferation and p42/p44 mitogen-activated protein kinase (MAPK) activation in human tracheal smooth muscle cells (TSMCs). Thrombin stimulated [3H]thymidine incorporation and p42/p44 MAPK phosphorylation in a time- and concentration-dependent manner in TSMCs. Pretreatment of TSMCs with pertussis toxin (PTX) significantly inhibited [3H]thymidine incorporation and phosphorylation of MAPK induced by thrombin. These responses were attenuated by tyrosine kinase inhibitors genistein and herbimycin A, phosphatidyl inositide (PI)-phospholipase C (PLC) inhibitor U73122, protein kinase C (PKC) inhibitor GF109203X, removal of Ca(2+) by addition of BAPTA/AM plus EGTA, and PI 3-kinase inhibitors wortmannin and LY294002. In addition, thrombin-induced [3H]-thymidine incorporation and p42/p44 MAPK phosphorylation was completely inhibited by PD98059 (an inhibitor of MEK1/2), indicating that activation of MEK1/2 was required for these responses. Furthermore, overexpression of dominant negative mutants, RasN17 and Raf-301, significantly suppressed p42/p44 MAPK activation induced by thrombin and PDGF-BB, indicating that Ras and Raf may be required for activation of these kinases. These results conclude that the mitogenic effect of thrombin was mediated through the activation of Ras/Raf/MEK/MAPK pathway. Thrombin-mediated MAPK activation was modulated by PI-PLC, Ca(2+), PKC, tyrosine kinase, and PI 3-kinase associated with cell proliferation in cultured human TSMCs.

Mitogenic effect of oxidized low-density lipoprotein on vascular smooth muscle cells mediated by activation of Ras/Raf/MEK/MAPK pathway

1. It has been demonstrated that oxidized low-density lipoprotein (OX-LDL) is a risk factor in atherosclerosis by stimulating vascular smooth muscle cell (VSMC) proliferation. However, the mechanisms of OX-LDL-induced cell proliferation are not completely understood. Therefore, we investigated the effect of OX-LDL on cell proliferation associated with mitogen-activated protein kinase (MAPK) activation in rat cultured VSMCs. 2. Both native-LDL (N-LDL) and OX-LDL induced a time- and concentration-dependent incorporation of [(3)H]-thymidine in VSMCs. 3. OX-LDL induced time- and concentration-dependent phosphorylation of p42/p44 MAPK. Pretreatment of these cells with pertussis toxin or U73122 attenuated the OX-LDL-induced responses. 4. Pretreatment with PMA for 24 h, preincubation with a PKC inhibitor staurosporine or the tyrosine kinase inhibitors, genistein and herbimycin A for 1 h, substantially reduced [(3)H]-thymidine incorporation and p42/p44 MAPK phosphorylation induced by OX-LDL. 5. Removal of Ca(2+) by BAPTA/AM or depletion of the internal Ca(2+) pool by thapsigargin significantly inhibited OX-LDL-induced [(3)H]-thymidine incorporation and p42/p44 MAPK phosphorylation. 6. OX-LDL-induced [(3)H]-thymidine incorporation and p42/p44 MAPK phosphorylation was inhibited by PD98059 (an inhibitor of MEK1/2) and SB203580 (an inhibitor of p38 MAPK) in a concentration-dependent manner. 7. Overexpression of dominant negative mutants of Ras (H-Ras-15A) and Raf (Raf-N4) significantly suppressed MEK1/2 and p42/p44 MAPK activation induced by OX-LDL and PDGF-BB, indicating that Ras and Raf may be required for activation of these kinases. 8. These results suggest that the mitogenic effect of OX-LDL is mediated through a PTX-sensitive G protein-coupled receptor that involves the activation of the Ras/Raf/MEK/MAPK pathway similar to that of PDGF-BB in rat cultured VSMCs.

Interleukin-1beta enhances bradykinin-induced phosphoinositide hydrolysis and Ca2+ mobilization in canine tracheal smooth-muscle cells: involvement of the Ras/Raf/mitogen-activated protein kinase (MAPK) kinase (MEK)/MAPK pathway

Elevated levels of several cytokines including interleukin-1beta (IL-1beta) have been detected in airway fluid of asthmatic patients. Inhalation of IL-1beta induced a bronchial hyper-reactivity to contractile agonists. However, the implication of IL-1beta in the pathogenesis of bronchial hyper-reactivity is not completely understood. Therefore, we investigated the effect of IL-1beta on bradykinin (BK)-induced inositol phosphate [Ins(X)P] accumulation and Ca2+ mobilization, and up-regulation of BK receptor density in canine cultured tracheal smooth-muscle cells (TSMCs). Treatment of TSMCs with IL-1beta potentiated BK-induced Ins(X)P accumulation and Ca2+ mobilization. However, there was no effect on the Ins(X)P response induced by endothelin-1, 5-hydroxytryptamine or carbachol. Treatment with platelet-derived growth factor B-chain homodimer (PDGF-BB) also enhanced the BK-induced Ins(X)P response. These enhancements by IL-1beta and PDGF-BB might be due to an up-regulation of BK B(2) receptor density (B(max)), since [(3)H]BK binding to TSMCs was inhibited by the B(2)-selective agonist and antagonist, BK and Hoe 140, but not by B(1)-selective reagents. The enhancing effects of IL-1beta and PDGF-BB on Ins(X)P accumulation, Ca2+ mobilization and B(max) were attenuated by PD98059 [an inhibitor of activation of mitogen-activated protein kinase (MAPK) kinase, MEK] and cycloheximide (an inhibitor of protein synthesis), suggesting that IL-1beta may share a common signalling pathway with PDGF-BB via protein synthesis. Furthermore, overexpression of dominant negative mutants, H-Ras-15A and Raf-N4, significantly suppressed the up-regulation of BK receptors induced by IL-1beta, indicating that Ras and Raf may be required for activation of these kinases. These results suggest that the augmentation of BK-induced responses produced by IL-1beta might be, at least in part, mediated through activation of the Ras/Raf/MEK/MAPK pathway in TSMCs.

Intrafamilial transmission and risk assessment of HTLV-I among blood donors in southern Taiwan

The human T-lymphotropic virus type I (HTLV-I) is one of the important etiological agents of adult T-cell leukemia/lymphoma and of HTLV-I associated myelopathy or tropical spastic paraparesis. There is still a lack of data concerning HTLV-I transmission by seropositive carriers in Taiwan. We investigated the patterns of HTLV-I intrafamilial transmission in HTLV-I seropositive blood donors and assessed the risk factors of HTLV-I transmission in relatives of HTLV-I carriers in Taiwan. A total of twenty HTLV-I seropositive donors and their 103 relatives were enrolled. Among those 103 relatives, 40 (38.8%) were seropositive for HTLV-I. Their ages ranged from one to 70 years old with a mean age of 31.0 +/- 1.65 year-old. Three of the ten wives of male carriers were HTLV-I seropositive. However, none of the six husbands of female carriers were HTLV-I seropositive. Mother-to-child vertical transmission was found in nine of 48 (18.8%) tested. Significant risk factors of HTLV-I transmission among relatives of HTLV-I carriers were hospital admission, previous transfusion, breast feeding, anti-HCV seropositivity and female relatives of age >/= 30 with odds ratio (OR) of 9.73, 8.64, 4.36, 8.86 and 4.91, respectively (all p < 0.05). Nonsignificant risk factors of HTLV-I transmission were sharing needles, operation history, HBsAg seropositivity and male relatives of age >/= 30. Our findings suggest that mother-to-child and husband-to-wife transmissions are the important forms of intrafamilial transmission of HTLV-I in Taiwan. Screening for HTLV-I in family members of HTLV-I seropositive blood donors may be warranted.

Scleral buckling for stage 4 retinopathy of prematurity

BACKGROUND AND OBJECTIVE

Both vitrectomy and scleral buckling have been used to treat patients with stage 4 retinopathy of prematurity (ROP). The standard procedure of scleral buckling for treatment of stage 4 ROP is encircling scleral buckling. The effectiveness of segmental scleral buckling is still unclear. The purpose of this study was to analyze the surgical results of patients with stage 4 retinopathy of prematurity treated with either encircling or segmental scleral buckling.

PATIENTS AND METHODS

We retrospectively analyzed the anatomic outcomes of 23 eyes (18 infants) with stage 4 A or B ROP treated with scleral buckling. Segmental buckling was used to treat 15 eyes with detachment limited to the temporal side of the retina, while 9 eyes with detachment involving both the nasal and temporal sides were treated with encircling scleral buckling.

RESULTS

Macular reattachment during a mean follow-up period of 34 months (range: 2 weeks to 9 years) was accomplished in 11 (79%) of the 14 eyes treated with segmental scleral buckling and 4 (44%) of the 9 eyes that received encircling scleral buckling. There were no intraoperative complications recorded. None of the eyes that achieved macular reattachment developed recurrent macular detachment during the follow-up period.

CONCLUSIONS

Scleral buckling appears to be effective for treatment of stage 4 ROP. In patients with temporal side retinal detachment only, segmental scleral buckling provides adequate treatment for stage 4 ROP.

P2Y(2) receptor-stimulated phosphoinositide hydrolysis and Ca(2+) mobilization in tracheal epithelial cells

Extracellular nucleotides have been implicated in the regulation of secretory function through the activation of P2 receptors in the epithelial tissues, including tracheal epithelial cells (TECs). In this study, experiments were conducted to characterize the P2 receptor subtype on canine TECs responsible for stimulating inositol phosphate (InsP(x)) accumulation and Ca(2+) mobilization using a range of nucleotides. The nucleotides ATP and UTP caused a concentration-dependent increase in [(3)H]InsP(x) accumulation and Ca(2+) mobilization with comparable kinetics and similar potency. The selective agonists for P1, P2X, and P2Y(1) receptors, N(6)-cyclopentyladenosine and AMP, alpha,beta-methylene-ATP and beta, gamma-methylene-ATP, and 2-methylthio-ATP, respectively, had little effect on these responses. Stimulation of TECs with maximally effective concentrations of ATP and UTP showed no additive effect on [(3)H]InsP(x) accumulation. The response of a maximally effective concentration of either ATP or UTP was additive to the response evoked by bradykinin. Furthermore, ATP and UTP induced a cross-desensitization in [(3)H]InsP(x) accumulation and Ca(2+) mobilization. These results suggest that ATP and UTP directly stimulate phospholipase C-mediated [(3)H]InsP(x) accumulation and Ca(2+) mobilization in canine TECs. P2Y(2) receptors may be predominantly mediating [(3)H]InsP(x) accumulation, and, subsequently, inositol 1,4,5-trisphosphate-induced Ca(2+) mobilization may function as the transducing mechanism for ATP-modulated secretory function of tracheal epithelium.