Pandrug-resistant Pseudomonas aeruginosa among hospitalised patients: clinical features, risk-factors and outcomes

Between 1 January 2003 and 31 December 2003, 37 patients had positive cultures of pandrug-resistant Pseudomonas aeruginosa (PDRPA) resistant to all commercially available anti-pseudomonal antimicrobial agents in Taiwan, including anti-pseudomonal penicillins, ceftazidime, fourth-generation cephalosporins, aztreonam, carbapenems, aminoglycosides and ciprofloxacin. Nineteen (51.4%) patients had PDRPA infections, including pneumonia (17 patients), catheter-related bacteraemia (one patient) and anal abscess (one patient). Eighteen patients were classified as having PDRPA colonisation, based on absence of clinical signs or symptoms of infection. In total, 92 isolates were recovered from various specimens, with the majority (85.9%) recovered from respiratory tract secretions (sputa, bronchial washings and pleural effusions), followed by urine (4.3%) and catheter tips (3.3%). Twenty-eight (75.7%) patients yielded cultures of non-PDR P. aeruginosa isolates before isolation of PDRPA, with a mean period between the first isolation of non-PDR P. aeruginosa and the isolation of PDRPA of 128.3 days. Most patients had received beta-lactam antibiotics, fluoroquinolones or carbapenems for prolonged periods. Univariate analysis showed that PDRPA infection, male gender and the presence of fever at the time of PDRPA isolation were associated with increased mortality.

Modulation of potassium currents by angiotensin and oxidative stress in cardiac cells from the diabetic rat

Diabetes induces oxidative stress and leads to attenuation of cardiac K+ currents. We investigated the role of superoxide ions and angiotensin II (ANG II) in generating and linking oxidative stress to the modulation of K+ currents under diabetic conditions. K+ currents were measured using patch-clamp methods in ventricular myocytes from streptozotocin (STZ)-induced diabetic rats. Superoxide ion levels, indicating oxidative stress, were measured by fluorescent labelling with dihydroethidium (DHE). ANG II content was measured using enzyme-linked immunosorbent asssay (ELISA). The results showed DHE fluorescence to be significantly higher in cells from diabetic males, compared to controls. Relief of stress by the NADPH oxidase inhibitor apocynin or by superoxide dismutase (SOD) but not by catalase reversed the attenuation of K+ currents and reduced DHE fluorescence. In cells from diabetic females, neither apocynin nor SOD augmented K+ currents, ANG II was not elevated and DHE fluorescence was significantly weaker than in cells from males. Reduced glutathione (GSH) also augmented K+ currents in cells from diabetic males but not females. In ovariectomized diabetic females K+ currents were augmented by GSH and apocynin. Current augmentation and the attenuation of DHE fluorescence by apocynin were significantly blunted by excess ANG II (300 nm). Diabetic male rats pretreated with the angiotensin-converting enzyme (ACE) inhibitor quinapril were hyperglycaemic, but their cellular ANG II levels and DHE fluorescence were significantly decreased. In cells from these rats, K+ currents were insensitive to apocynin. In conclusion, diabetes-related oxidative stress attenuates K+ currents through ANG II-generated increased superoxide ion levels. When ANG II levels are lower, as in diabetic females or following ACE inhibition in males, oxidative stress is reduced, with blunted alterations in K+ currents.

A methoxy derivative of resveratrol analogue selectively induced activation of the mitochondrial apoptotic pathway in transformed fibroblasts

Resveratrol (R-3), a trihydroxy trans-stilbene from grape, inhibits multistage carcinogenesis in animal models. A resveratrol derivative 3,4,5,4′-tetrahydroxystilbene (R-4) exhibits potent growth inhibitory effect against transformed human cells. Here we report that 3,4,5,4′-tetramethoxystilbene (MR-4), converted from R-4, was more potent against cancer cell lines (WI38VA, IMR-90SV, HeLa, LNCaP, HT-29, and HepG2), but had almost no inhibitory effect on the growth of normal cells (WI38, IMR-90, BJ-T) at the concentrations tested. The IC₅₀ value of MR-4 on the growth inhibition of transformed WI38VA human cells was 0.5 μM, as compared to the value of greater than 50 μM for the normal WI38 cells. Resveratrol, however, did not exhibit such clear differential effect and the IC₅₀ value of R-3 for WI38VA cells was about 50 μM. The growth inhibitory effect of MR-4 correlated with the induction of apoptosis in the transformed cells. When normal WI38 cells and transformed WI38VA cells were compared, MR-4 induced increases of the Bax/Bcl-2 mRNA ratio, p53 and Bax protein level, activation of caspases, and DNA fragmentation in transformed, but not in normal cells. Further analysis revealed that MR-4 caused a rapid appearance of perinuclear aggregation of mitochondria in WI38VA but not in WI38 cells, suggesting that the mitochondria could serve as an early target of MR-4. R-3 also induced apoptosis and mitochondrial clustering but only at a much higher concentration, close to 500 μM. Taken together, the specific activation of the mitochondria-mediated apoptotic pathway could be a major reason for the striking differential growth inhibitory effect of MR-4.

Patterns of physical activity in free-living adults in the Southern United States

OBJECTIVE

To examine the relationship between the amount and patterns of physical activity (PA), body fatness, and age in a heterogeneous adult population in the free living.

DESIGN

Cross-sectional study of the amount of PA over a 1-week period. The amount of body movements during PA (PA counts*10(3)) and time spent on various PA intensity categories were calculated from a triaxial accelerometer and compared with subject characteristics, including body fat from hydrodensitometry.

PARTICIPANTS

Adult healthy men (n=48) and women (n=72) were recruited from the Nashville, Tennessee area and their PA was monitored in their free-living environment.

RESULTS

The average weekday PA counts (176.5+/-60.3, P=0.002, r(2)=0.294), PA counts day-to-day variability (47.3+/-32.7, P=0.002, r(2)=0.286), daily maximum PA counts (241.9+/-89.2, P=0.001, r(2)=0.327), minute-to-minute variability on weekdays (0.281+/-0.091, P=0.001, r(2)=0.362), and the difference between maximum and minimum daily PA counts (130.6+/-78.3, P=0.008, r(2)=0.243) were significantly and negatively correlated with body fatness. During awake time, both men and women spent 10-12 h on low intensity (1.0-2.9 metabolic equivalents (METs)) PA, approximately 1 h on moderate (3.0-5.9 MET), and less than 10 min on vigorous (>6.0 MET) PA each day. On weekends, men and women spent more time at rest (1 MET), less time on low-intensity PA, and men spent more time on moderate PA than on weekdays.

CONCLUSIONS

In adults living in the Southern US the amount of free-living PA was negatively correlated with body fatness. Both men and women spent the majority of active time on low and moderate PA. PA patterns on weekends were different than on weekdays and were related to sex and age, but not to body fatness.

SPONSORSHIP

National Institutes of Health, US.

A feasibility study on the predictive emission monitoring system applied to the Hsinta power plant of Taiwan Power Company

The continuous emission monitoring system (CEMS) can monitor flue gas emissions continuously and instantaneously. However, it has the disadvantages of enormous cost, easily producing errors in sampling periods of bad weather, lagging response in variable ambient environments, and missing data in daily zero and span tests and maintenance. The concept of a predictive emission monitoring system (PEMS) is to use the operating parameters of combustion equipment through thermodynamic or statistical methods to construct a mathematic model that can predict emissions by a computer program. The goal of this study is to set up a PEMS in a gas-fired combined cycle power generation unit at the Hsinta station of Taiwan Power Co. The emissions to be monitored include nitrogen oxides (NOx) and oxygen (O2) in flue gas. The major variables of the predictive model were determined based on the combustion theory. The data of these variables then were analyzed to establish a regression model. From the regression results, the influences of these variables are discussed and the predicted values are compared with the CEMS data for accuracy. In addition, according to the cost information, the capital and operation and maintenance costs for a PEMS can be much lower than those for a CEMS.

Meta-analysis: ribavirin-induced haemolytic anaemia in patients with chronic hepatitis C

AIM

To use meta-analysis to study the risk of anaemiarelated to ribavirin therapy for chronic hepatitisC.

METHODS

The MEDLINE database up to January 2001 was searched for randomized controlled trials of ribavirin (monotherapy or combined with interferon) for chronic hepatitis C. The outcomes evaluated were withdrawal from the study due to anaemia, ribavirin dosage reduction due to a decrease in haemoglobin and haemoglobin levels below 10 g/dL.

RESULTS

Based on 17 studies, the overall risk difference (ribavirin vs. no ribavirin) for anaemia was 0.09 [95% confidence interval (CI), 0.04-0.13]. Two Asian studies reported risk differences of 0.29 and 0.22, greater than the pooled risk difference of 0.07 (95% CI, 0.03-0.12) for 15 non-Asian studies. The risk associated with 1 g or more of ribavirin per day was higher (risk difference, 0.09; 95% CI, 0.04-0.14) than that for 0.8 g of ribavirin per day (risk difference, 0.01; 95% CI, - 0.04-0.06).

CONCLUSIONS

Chronic hepatitis C patients treated with 1 g or more of ribavirin per day were at a higher risk of developing anaemia. Reported risks were higher among Asian studies, which may be due to differences in study entrance criteria, dosage titration strategy or ethnic vulnerability.

Possible role of subunit A of nuclear factor Y (NF-YA) in normal human diploid fibroblasts during senescence

NF-Y, a heterotrimeric CCAAT binding protein, may have a role in regulating some G1/S genes whose expressions are attenuated during replicative senescence [Matuoka and Chen (1999) Exp Cell Res 253: 365-371]. The hallmark of replicative senescence is the loss of dividing potential. Hence, attenuation of G1/S gene expressions may be causally related to aging. To understand how NF-Y is involved in regulating G1/S genes during replicative senescence, we have examined the expressions of three NF-Y subunit genes in human IMR-90 cells over the entire course of their life-span. The mRNA levels of NF-YA, B, and C did not show any age-dependent change. In contrast, the protein level of NF-YA exhibited a significant and progressive decrease during cell senescence. Cross-linking experiments indicated that NF-Y may interact with proteins such as GCN5 and P/CAF. Co-transfection of cells with plasmid encoding NF-YA protein enhanced the expression of reporter gene fused with G1/S gene promoter that contains NF-Y sites. In contrast, co-transfection with plasmid encoding the dominant negative NF-YA mutant suppressed the expression of the reporter genes. Transient transfection of human cells with dominant negative NF-YA mutant could lead to an increase in neutral beta-galactosidase activity, a marker of cell senescence. These results support the view that NF-Y may have a role in cell senescence.

Rapid reversion of aging phenotypes by nicotinamide through possible modulation of histone acetylation

Aging appears to be an irreversible process. Here we report that nicotinamide (NAA) can induce rapid and reversible reversion of aging phenotypes in human diploid fibroblasts in terms of cell morphology and senescence-associated beta-galactosidase activity. Although NAA seems to enhance the replicative potential of the cells, it has little effect on their growth rate and life span, suggesting that NAA action is rather separated from the cellular replicative system. The effects are unique to NAA: none ofthe NAA-related compounds examined (an NAD precursor/niacin, NAD analogs, and poly(ADP-ribose) polymerase inhibitors) exerted similar effects. Thus, NAD-related metabolism and poly(ADP-ribosyl)ation are unlikely related to the NAA action. On the other hand, histone acetyltransferase (HAT) activity was elevated in NAA-exposed cells, while in aged cells, HAT activity and histone H4 acetylation were lowered. Taken together, the results suggest that NAA may cause rejuvenation by restoring, at least in part, altered gene expression in aged cells through its activation of HAT.

Acupuncture for general veterinary practice

Since the International Society of Veterinary Acupuncture (IVAS) was founded in 1974, acupuncture (AP) has received greater acceptance by veterinary professionals throughout the world. This article introduces some important animal diseases that respond well to AP therapy. These include resuscitation of small animals, treatment of anoestrous gilts and sows, bovine reproductive disease, canine vertebral problems and equine backpain, etc. Conventional medicine considers these to be difficult cases to treat. Veterinarians have become more aware of the benefits of AP especially for those diseases, thanks to the efforts of experienced practitioners and scientists, and the many published reports on veterinary AP that have introduced some good indications for AP therapy in veterinary practice. Possible mechanisms behind the effectiveness of AP are discussed. This article aims to introduce veterinarians to good indications for AP to initiate their interest in the practice of AP. Although this is a rapidly expanding field, a long march must begin with one step. We wish this article to be the shoes for such a march. For more information on veterinary AP, contact IVAS <ivasoffice@aol.com>, P.O. Box 1478, Longmont, CO.. 80502, USA (http://www.ivas.org), or your national veterinary acupuncture society (http://www.komvet.at/ ivadkom/vapsocs.htm).

Ligands of macrophage scavenger receptor induce cytokine expression via differential modulation of protein kinase signaling pathways

Our previous works demonstrated that ligands of macrophage scavenger receptor (MSR) induce protein kinases (PKs) including protein-tyrosine kinase (PTK) and up-regulate urokinase-type plasminogen activator expression (Hsu, H. Y., Hajjar, D. P., Khan, K. M., and Falcone, D. J. (1998) J. Biol. Chem. 273, 1240--1246). To continue to investigate MSR ligand-mediated signal transductions, we focus on ligands, oxidized low density lipoprotein (OxLDL), and fucoidan induction of the cytokines tumor necrosis factor-alpha (TNF) and interleukin 1 beta (IL-1). In brief, in murine macrophages J774A.1, OxLDL and fucoidan up-regulate TNF production; additionally, fucoidan but not OxLDL induces IL-1 secretion, prointerleukin 1 (proIL-1, precursor of IL-1) protein, and proIL-1 message. Simultaneously, fucoidan stimulates activity of interleukin 1-converting enzyme. We further investigate the molecular mechanism by which ligand binding-induced PK-mediated mitogen-activated protein kinase (MAPK) in regulation of expression of proIL-1 and IL-1. Specifically, fucoidan stimulates activity of p21-activated kinase (PAK) and of the MAPKs extracellular signal-regulated kinase (ERK), c-Jun NH(2)-terminal kinase (JNK), and p38. Combined with PK inhibitors and genetic mutants of Rac1 and JNK in PK activity assays, Western blotting analyses, and IL-1 enzyme-linked immunosorbent assay, the role of individual PKs in the regulation of proIL-1/IL-1 was extensively dissected. Moreover, tyrosine phosphorylation of pp60Src as well as association between pp60Src and Hsp90 play important roles in fucoidan-induced proIL-1 expression. We are the first to establish two fucoidan-mediated signaling pathways: PTK(Src)/Rac1/PAK/JNK and PTK(Src)/Rac1/PAK/p38, but not PTK/phospholipase C-gamma 1/PKC/MEK1/ERK, playing critical roles in proIL-1/IL-1 regulation. Our current results indicate and suggest a model for MSR ligands differentially modulating specific PK signal transduction pathways, which regulate atherogenesis-related inflammatory cytokines TNF and IL-1.

Inhibition of ryanodine binding to sarcoplasmic reticulum vesicles of cardiac muscle by Zn(2+) ions

Using the assay of [(3)H]ryanodine binding to the sarcoplasmic reticulum, the effect of Zn(2+) on ryanodine receptors (RyRs) of cardiac muscle was investigated. There was no obvious change in the binding at [Zn(2+)](f) of less than 0.2 microM. However, a decrease of the binding became significant with raising [Zn(2+)](f) to 0.5 microM. The inhibitory effect of Zn(2+) was [Zn(2+)](f)-dependent, with IC(50/ZnI) of 2.1+/-0.4 microM (mean+/-S.D.). Scatchard analysis indicates that both an increase of K(d) and a decrease of B(max) were responsible for Zn(2+)-induced decrease of the binding. The Hill coefficient for this inhibitory effect of Zn(2+) was between 0.8 and 1.2. The interactions of the effects of Zn(2+) and various modulators of RyR indicate that the inhibitory effect of Zn(2+) was mostly mediated through inhibiting Ca(2+) activation sites (CaA) on RyR. Since the [Zn(2+)](f) dependence was not clearly changed by [Ca(2+)](f), the inhibitory effect of Zn(2+) may not be due to competition of Zn(2+) with Ca(2+) for CaA and probably is indirect. The inhibitory effect of Zn(2+) could not be antagonized by 2 mM dithiothreitol, a thiol-reducing agent, suggesting that the binding of Zn(2+) ions to RyRs of cardiac muscle is not accompanied by obvious change of redox state of the RyRs. In comparison with that seen in skeletal muscle [3], the effects of Zn(2+) on ryanodine binding to the sarcoplasmic reticulum of cardiac muscle show several distinct differences. It is indicated that the effect of Zn(2+) on RyRs may be isoform-dependent. The physiological significance of the effects of Zn(2+) is discussed.

Pulmonary fungal infection: emphasis on microbiological spectra, patient outcome, and prognostic factors

STUDY OBJECTIVES

To investigate the microbiological spectra, patient outcome, and prognostic factors of pulmonary fungal infection.

DESIGN

The medical and microbiological records of patients with pulmonary fungal infection were retrospectively analyzed.

SETTING

A university-affiliated tertiary medical center.

PATIENTS AND METHODS

From January 1988 to December 1997, all cases of pulmonary fungal infection were reviewed. The criteria for inclusion were obvious lung lesion shown on chest radiographs and one of the following: (1) the presence of fungi in or isolation of fungi from the biopsy specimen of open thoracotomy, thoracoscopy, transbronchial lung biopsy, or ultrasound-guided percutaneous needle aspiration/biopsy; or (2) isolation of fungi from pleural effusion or blood, with no evidence of extrapulmonary infection.

RESULTS

A total of 140 patients were included. Ninety-four cases of pulmonary fungal infection (67%) were community acquired. The most frequently encountered fungi were Aspergillus species (57%), followed by Cryptococcus species (21%) and Candida species (14%). There were 72 patients with acute invasive fungal infection, with a mortality rate of 67%. Multivariate logistic regression analysis showed that nosocomial infection (p = 0.014) and respiratory failure (p = 0.001) were significantly and independently associated with death of acute invasive fungal infection.

CONCLUSIONS

Pulmonary fungal infection of community-acquired origins is becoming a serious problem. It should be taken into consideration for differential diagnosis of community-acquired pneumonia. Furthermore, acute invasive fungal infection is associated with a much higher mortality rate for patients with nosocomial infection or complicating respiratory failure. Early diagnosis with prompt antifungal therapy, or even with surgical intervention, might be warranted to save patients' lives.

Detection of Epstein-Barr virus DNA in the peripheral-blood cells of patients with nasopharyngeal carcinoma: relationship to distant metastasis and survival

PURPOSE

Nasopharyngeal carcinoma (NPC) has been proved to be an Epstein-Barr virus (EBV)-associated cancer. By use of nested polymerase chain reactions (PCRs), we examined whether the presence of EBV DNA in the peripheral-blood cells (PBC) can serve as a prognostic indicator for NPC.

PATIENTS AND METHODS

Peripheral blood from 124 patients with NPC who had no evidence of distant metastasis and 114 healthy volunteers with serologically positive findings for EBV infection was collected prospectively. Plasma and erythrocytes were separated. DNA was extracted from PBCs and analyzed by a nested PCR using primers specific to Epstein-Barr virus nuclear antigen 1 (EBNA-1). All patients were treated by radiotherapy with or without chemotherapy. Clinical parameters and status of EBNA-1 in PBCs were used for survival analysis using the Kaplan-Meier method and the Cox proportional hazards model.

RESULTS

Positive rates of EBNA-1 DNA in PBCs of NPC patients and healthy volunteers are 71% and 14%, respectively (P =.001). No significant difference was observed with regard to the clinical characteristics of patients who were EBNA-1-positive (n = 88) and those who were EBNA-1-negative (n = 36). After a median follow-up period of 38 months (range, 24 to 56 months), 29 of 88 EBNA-1-positive patients and only one of 36 EBNA-1-negative patients developed distant metastases (P =.00015). Kaplan-Meier estimates of overall survival (P =.0010), metastasis-free survival (P =.0004), and progression-free survival (P =.0004) were significantly lower for the patients in the EBNA-1-positive group than for those in the EBNA-1-negative group. Multivariate Cox analysis confirmed the same results.

CONCLUSION

The presence of EBNA-1 DNA in PBCs is a novel, important risk factor for patients with NPC that indicates a significantly higher risk of developing distant metastasis as well as a lower survival rate.

Increased bone turnover is associated with protein and energy metabolism in adolescents with sickle cell anemia

Contribution of bone turnover to the hypercatabolic state observed in sickle cell anemia is unknown. We examined the association between markers of bone turnover and basal rates of whole body protein turnover and energy expenditure in 28 adolescents with homozygous sickle cell anemia (HbSS) and in 26 matched controls with normal phenotype (HbAA). Whole body protein breakdown and synthesis were measured using a stable isotope of [15N]glycine, resting energy expenditure was measured by whole room indirect calorimetry, and the rate of pyridinoline cross-link (PYD) excretion in urine and fasting serum levels of the type I procollagen carboxy-terminal propeptide (PICP) were measured with commercial kits. Urinary PYD and serum PICP were significantly elevated in HbSS patients. The increase in procollagen synthesis, indicated by high levels of PICP, was significantly correlated with increased whole body protein synthesis. The increase in type I collagen degradation, indicated by high PYD excretion, was significantly correlated with increased protein breakdown. We conclude that increased rates of bone turnover contribute to the increased rates of protein turnover and energy expenditure observed in adolescents with homozygous sickle cell anemia.

Resveratrol analog, 3,4,5,4'-tetrahydroxystilbene, differentially induces pro-apoptotic p53/Bax gene expression and inhibits the growth of transformed cells but not their normal counterparts

Resveratrol, a trihydroxystilbene found in grapes and other plants, has been shown to be active in inhibiting multistage carcinogenesis. Using resveratrol as a prototype, we have synthesized a number of polyhydroxy- and polymethoxy-stilbenes and tested their anti-proliferative effect in normal and transformed human cells. Here we show that one of the resveratrol analogs, 3,4,5,4'-tetrahydroxystilbene (R-4), specifically inhibited the growth of SV40 virally transformed WI38 cells (WI38VA) at 10 microM, but had no effect on normal WI38 cells at even higher concentrations. R-4 also prominently induced apoptosis in WI38VA cells, but not in WI38 cells. RNase protection assay showed that R-4 significantly induced the expression of p53, GADD45 and Bax genes and concomitantly suppressed the expression of bcl-2 gene in WI38VA, but not in WI38 cells. A large increase in p53 DNA binding activity and the presence of p53 in the Bax promoter binding complex suggested that p53 was responsible for the Bax gene expression induced by R-4 in transformed cells. Within 4 h of treatment with R-4, the Bax to bcl-2 protein ratio in WI38 and WI38VA cells was, respectively, 0.1 and 105, a difference of three orders of magnitude. While R-4 prominently induced the p53/Bax pro-apoptotic genes, it also concomitantly suppressed the expression of Cox-2 in WI38VA cells. Taken together, our study suggests that the induction of p53 gene by R-4 in transformed cells may play a key role in the differential growth inhibition and apoptosis of transformed cells.

Hypusine is required for a sequence-specific interaction of eukaryotic initiation factor 5A with postsystematic evolution of ligands by exponential enrichment RNA

Hypusine is formed through a spermidine-dependent posttranslational modification of eukaryotic initiation factor 5A (eIF-5A) at a specific lysine residue. The reaction is catalyzed by deoxyhypusine synthase and deoxyhypusine hydroxylase. eIF-5A is the only protein in eukaryotes and archaebacteria known to contain hypusine. Although both eIF-5A and deoxyhypusine synthase are essential genes for cell survival and proliferation, the precise biological function of eIF-5A is unclear. We have previously proposed that eIF-5A may function as a bimodular protein, capable of interacting with protein and nucleic acid (Liu, Y. P., Nemeroff, M., Yan, Y. P., and Chen, K. Y. (1997) Biol. Signals 6, 166-174). Here we used the method of systematic evolution of ligands by exponential enrichment (SELEX) to identify the sequence specificity of the potential eIF-5A RNA targets. The post-SELEX RNA obtained after 16 rounds of selection exhibited a significant increase in binding affinity for eIF-5A with an apparent dissociation constant of 1 x 10(-7) m. The hypusine residue was found to be critical for this sequence-specific binding. The post-SELEX RNAs shared a high sequence homology characterized by two conserved motifs, UAACCA and AAUGUCACAC. The consensus sequence was determined as AAAUGUCACAC by sequence alignment and binding studies. BLAST analysis indicated that this sequence was present in > 400 human expressed sequence tag sequences. The C terminus of eIF-5A contains a cold shock domain-like structure, similar to that present in cold shock protein A (CspA). However, unlike CspA, the binding of eIF-5A to either the post-SELEX RNA or the 5'-untranslated region of CspA mRNA did not affect the sensitivity of these RNAs to ribonucleases. These data suggest that the physiological significance of eIF-5A-RNA interaction depends on hypusine and the core motif of the target RNA.

Protein-tyrosine phosphatase D1, a potential regulator and effector for Tec family kinases

Etk, also named Bmx, is a member of the Tec tyrosine kinase family, which is characterized by a multimodular structure including a pleckstrin homology (PH) domain, an SH3 domain, an SH2 domain, and a catalytic domain. The signaling mechanisms regulating Etk kinase activity remain largely unknown. To identify factor(s) regulating Etk activity, we used the PH domain and a linker region of Etk as a bait for a yeast two-hybrid screen. Three independent clones encoding protein-tyrosine phosphatase D1 (PTPD1) fragments were isolated. The binding of PTPD1 to Etk is specific since PTPD1 cannot associate with either the Akt PH domain or lamin. In vitro and in vivo binding studies demonstrated that PTPD1 can interact with Etk and that residues 726-848 of PTPD1 are essential for this interaction. Deletion analysis of Etk indicated that the PH domain is essential for PTPD1 interaction. Furthermore, the Etk-PTPD1 interaction stimulated the kinase activity of Etk, resulting in an increased phosphotyrosine content in both factors. The Etk-PTPD1 interaction also increased Stat3 activation. The effect of PTPD1 on Etk activation is specific since PTPD1 cannot potentiate Jak2 activity upon Stat3 activation. In addition, Tec (but not Btk) kinase can also be activated by PTPD1. Taken together, these findings indicate that PTPD1 can selectively associate with and stimulate Tec family kinases and modulate Stat3 activation.

Sonographic septation: a useful prognostic indicator of acute thoracic empyema

The aim of this study was to identify sonographic predictors of patient outcomes or need for surgical intervention of acute thoracic empyema. All patients with a clinical diagnosis of thoracic empyema underwent transthoracic ultrasonographic examination and thoracentesis at admission. According to the presence or absence of septa in sonographic images, the patients were classified into two groups: septated and nonseptated. Sonographic findings were analyzed with respect to duration of hospital stay, chest tube drainage, and treatment efficacy. A total of 163 consecutive patients were included in the study (83 patients with septated and 80 with nonseptated sonographic images). The mean duration of hospital stay (35.4 versus 27.0 days, P = 0.009) and chest tube drainage (13.1 versus 7.6 days, P < 0.001) for the patients with septa were significantly longer than for those without septa. The patients with septa were more likely to undergo intrapleural fibrinolytic therapy (63.8% versus 38.8%, odds ratio 2.79, P = 0.001) and surgical intervention (24.3% versus 7.5%, odds ratio 3.92, P = 0.004). We concluded that sonographic septation is a useful sign to predict the need for subsequent intrapleural fibrinolytic therapy and surgical intervention in cases of acute thoracic empyema. Early fibrinolytic therapy or even surgical intervention may be indicated in patients with sonographic septations.

Differential effects of theaflavin monogallates on cell growth, apoptosis, and Cox-2 gene expression in cancerous versus normal cells

Theaflavin (TF-1), theaflavin-3-monogallate and theaflavin-3'-monogallate mixture (TF-2), and theaflavin-3,3'-digallate (TF-3) are the major black tea polyphenols. Here we compared the effects of these polyphenols on cell growth, apoptosis, and gene expression in normal and cancerous cells. We showed that TF-2 (10-50 microM) inhibited the growth of SV40 transformed WI38 human cells (WI38VA) and Caco-2 colon cancer cells but had little effect on the growth of their normal counterparts. The IC50s of TF-2 for the growth inhibition of WI38 and WI38VA cells were, respectively, 300 and 3 microM. The other two black tea polyphenols, TF-1 and TF-3, did not exhibit such differential growth-inhibitory effect. TF-2, but not TF-1 or TF-3, induced apoptosis in transformed WI38VA cells but not in normal WI38 cells, suggesting that apoptosis was responsible, at least in part, for the differential growth-inhibitory effect of TF-2. Cox-2 has been implicated in intestinal carcinogenesis. Among the tea polyphenols tested, TF-2 and, to a lesser degree, (-)-epigallocatechin gallate inhibited cyclooxygenase (Cox)-2 gene expression. TF-2 at 50 microM completely blocked the serum-induced Cox-2 gene expression at both mRNA and protein level. Other genes, including c-fos, c-myc, thymidine kinase, proliferating cell nuclear antigen, BRCA1, BRCA2, and Cox-1, were not significantly affected by TF-2. These findings suggest that TF-2 may be responsible, at least in part, for the chemopreventive activity in black tea extracts.

Aminohexanoic hydroxamate is a potent inducer of the differentiation of mouse neuroblastoma cells

Deoxyhypusine synthase is the key enzyme for modifying a lysine residue to hypusine in the cellular protein eukaryotic initiation factor 5A (eIF-5A). Deletion of the deoxyhypusine synthase or the eIF-5A gene in yeast produces lethal phenotype. Inhibition of deoxyhypusine synthase by 1-guanidino-7-aminoheptane (GC7) suppresses tumor cell growth. Hypusine formation represents one of the most specific polyamine-dependent biochemical reactions. In view of the importance of polyamines in growth regulation and cancer biology, deoxyhypusine synthase has been considered to be a good target for chemotherapeutic drug design. Using GC7 as a prototype we have synthesized and tested three classes of diamine analogs, namely, guanidino-, pyrimidino-, and hydroxamate derivatives, as potential inhibitors for deoxyhypusine synthase. Our study shows that (i) among all the compounds tested, GC7 remained to be the most potent inhibitor for deoxyhypusine synthase; (ii) N,N'-bispyrimidino-1, 9-diaminononane, although a poor inhibitor of deoxyhypusine synthase, was a potent growth inhibitor; and (iii) one of the hydroxamate derivatives, 6-aminohexanoic hydroxamate (HC6), prominently induced the differentiation of mouse neuroblastoma cells at sub-millimolar concentrations. Interestingly, other hydroxamates with different chain length were not nearly as effective as HC6 in inducing neuroblastoma cell differentiation. The effect of HC6 was also unique in that it could induce neurite outgrowth and the expression of neuron-specific genes such as synapsin I and MAP-2 in neuroblastoma cells in the absence of other promoting agents such as cAMP. The effect of HC6 on neuroblastoma cell differentiation was comparable with, or better than that of N(6),O(2)'-dibutyryl cAMP (Bt(2)cAMP), a standard reagent commonly used for inducing the differentiation of mouse and human neuroblastoma cells in culture.

Activation of heat shock factor 1 by hyperosmotic or hypo-osmotic stress is drastically attenuated in normal human fibroblasts during senescence

We have previously reported that osmotic stress prominently induces the DNA binding activity of the heat shock transcription factor 1 (HSF1). In the present study, we examined the effects of medium osmolarity on both the activation of HSF1 and the programmed cell death in normal human fibroblasts during cellular senescence. The activation of HSF1 occurred rapidly in presenescent (early passage) IMR-90 cells when exposed to either hypo-osmotic or hyperosmotic stress. In contrast, the activation of HSF1 was significantly attenuated in senescent cells. Western blot analysis indicated that equal amounts of HSF1 were present as monomers in the cytoplasm of both presenescent and senescent cells in normal growth medium. Under either hypo-osmotic or hyperosmotic stress, trimerization and nuclear localization of HSF1 occurred in presenescent cells but not in senescent cells. More than 80% of HSF1 in senescent cells remained as monomers in the cytoplasm under osmotic stress, suggesting a defect in the signal transduction pathways that lead to HSF1 trimerization or a dysfunction in the HSF1 protein itself. Possible involvement of mitogen-activated protein kinase (MAPK) signal transduction pathways in the activation HSF1 was investigated by monitoring the activation of the three MAPKs, ERK1/2, JNK1/2, and p38, in cells exposed to hypo-osmotic or hyperosmotic stress. All three MAPKs were activated by hyperosmotic stress but not hypo-osmotic stress, suggesting that the MAPK signal transduction pathways may not be directly linked to the osmotic stress-induced activation of HSF1. In contrast to the rapid heat shock transcription factor (HSF) activation, apoptosis occurred only after long-term exposure to hypo-osmotic or hyperosmotic stress. Despite the prominent induction of HSF1 activation, the presenescent cells were more sensitive than the senescent cells to the osmotic stress-induced apoptosis.

A 10-year experience with bacteriology of acute thoracic empyema: emphasis on Klebsiella pneumoniae in patients with diabetes mellitus

STUDY OBJECTIVES

To provide an updated evaluation of the bacteriology of acute thoracic empyema for more efficacious treatment.

DESIGN

: The medical and microbiological records of all patients who received a diagnosis of acute thoracic empyema were reviewed. Based on the bacteria isolated from the pleural fluid, the patients were classified into the following four groups: aerobic or facultative Gram-positive; aerobic Gram-negative; anaerobic; and mixed.

SETTING

A university-affiliated tertiary medical center.

PATIENTS AND METHODS

From January 1989 to December 1998, 171 patients with a diagnosis of acute thoracic empyema were treated. A comparative analysis of the isolates from pleural effusions, the mean length of hospital stay, the mean duration of chest tube drainage, the mean duration between the onset of symptoms and the establishment of diagnosis, treatment efficacy, and the need for subsequent intervention was performed.

RESULTS

A total of 163 microorganisms were isolated from the pleural fluid of 139 patients. These patients were classified according to the following types of isolates: aerobic or facultative Gram-positive (n = 47); aerobic Gram-negative (n = 59); anaerobic (n = 14); and mixed (n = 19). Klebsiella pneumoniae was the most commonly isolated pathogen (24. 4%) and was strongly associated with a diagnosis of diabetes mellitus. The mortality rate of patients with aerobic Gram-negative bacilli isolated was the highest (22.0%), followed by those with mixed pathogens isolated (15.7%), aerobic or facultative Gram-positive (6.4%), and anaerobic (0%).

CONCLUSIONS

The increasing incidence of acute thoracic empyema caused by Gram-negative bacilli, especially by K pneumoniae, has become an increasing problem. The isolation of aerobic Gram-negative bacilli or multiple pathogens from pleural fluid is associated with a poor prognosis and indicates a need for more aggressive antimicrobial chemotherapy.

Fungal empyema thoracis: an emerging clinical entity

STUDY OBJECTIVES

To analyze the clinical spectra, pathogenesis, treatment, outcome, and prognostic factors of fungal empyema thoracis.

DESIGN

The medical records of patients with positive fungal cultures from pleural effusions were retrospectively analyzed.

SETTING

A university-based tertiary care hospital in Taipei, Taiwan.

PATIENTS AND METHODS

From January 1990 through December 1997, patients diagnosed with fungal empyema were included in this study. The criteria for diagnosis of fungal empyema thoracis were as follows: (1) isolation of a fungal species from the pleural effusion; (2) significant signs of infection, such as fever (body temperature > 38.3 degrees C) and leukocytosis (white blood cell > 10,000/microL); and (3) isolation of the same mold species from pleural effusion on more than one occasion, or from pleural effusion and other specimens such as blood, sputum, or surgical wounds that showed evidence of tissue invasion.

RESULTS

Sixty-seven patients with fungal empyema thoracis were included. Their mean age was 54 years (range, 2 weeks to 93 years), and 64% (43 patients) were men. Fifty-seven patients (85%) had various underlying diseases, and 18 (27%) had more than one immunocompromising condition. A total of 73 fungal isolates were recovered from pleural effusion; the most commonly encountered were Candida species (47 isolates, 64%), Torulopsis glabrata (13 isolates, 18%), and Aspergillus species (9 isolates, 12%). Candida albicans (28 isolates) was the most common Candida species, followed by Candida tropicalis (13 isolates). Six patients (9%) had two fungal strains isolated, and 16 (24%) had concomitant bacterial empyema thoracis. Eighteen patients (27%) had concurrent fungemia. Most (56 patients, 84%) cases of fungal empyema thoracis were nosocomial, and many case (43 patients, 64%) were acquired in ICUs. Abdominal disease (20 patients, 30%), especially previous abdominal surgery and GI perforation (12% and 10%, respectively), was the most common cause of fungal empyema thoracis, followed by bronchopulmonary infection (15 patients, 22%) and chest surgery (12 patients, 18%). Forty-nine patients (73%) received systemic antifungal therapy, and 38 (57%) underwent closed drainage therapy. Eleven patients (16%) underwent pleural irrigation with normal saline solution, povidone-iodine solution, or antifungal agents. Six patients (9%) finally received decortication. All patients receiving surgery or pleural irrigation with antifungal agents survived. Despite the aforementioned management, the crude mortality was high (73%). Multivariate analysis showed a significantly increased risk of death in immunocompromised patients (relative risk, 1.58; p < 0.005) and those with respiratory failure (relative risk, 2.31; p < 0.001). Systemic antifungal therapy was associated with a significantly lower risk of death (relative risk, 0.69; p < 0.05).

CONCLUSION

These data imply an increasing incidence of fungal empyema thoracis in recent years and the necessity for aggressive treatment of patients with this disease.

Bacteriology of infected cavitating lung tumor

Differentiation between in situ infection and simple tumor necrosis in cavitating lung tumors by means of imaging studies is difficult. In this study, we prospectively investigated the role of ultrasound (US)-guided transthoracic aspiration for bacteriologic examination of infected cavitating lung tumors, and the influence of the culture results on the treatment of patients. Twenty-two patients (18 men and four women) with cavitating lung tumors treated from January 1996 to October 1998 were included. All patients underwent US-guided transthoracic aspiration for bacterial, fungal, and mycobacterial cultures. Microorganisms were isolated from six of seven febrile patients and one of 15 nonfebrile patients. A total of nine pathogens were isolated from seven patients: Klebsiella pneumoniae (n = 3); Haemophilus influenzae (n = 2); Enterococcus faecium (n = 1); Bifidobacterium (n = 1); Shewanella putrefaciens (n = 1); and Mycobacterium tuberculosis (n = 1). Two pathogens were isolated from the aspirate cultures in two patients, while the others had monomicrobial infection. The six febrile patients who had positive lung aspirate cultures were treated with empiric antimicrobial agents before the culture results were available, and the culture results led to adjustment of the antibiotic regimen in five of these. The clinical conditions of the six patients with infected cavitating lung tumors improved after the initiation of individualized antimicrobial treatment. Pneumothorax occurred in one patient, and was the sole procedure-related complication. In conclusion, US-guided transthoracic aspiration is helpful for differentiating infected cavitating lung tumors from simple tumor necrosis. Infection in cavitating lung tumors is common among febrile patients, and the culture results can guide modification of the antimicrobial therapy.

Plasma leptin association with body composition and energy expenditure in sickle cell disease

OBJECTIVE

To examine the association between fasting plasma leptin concentrations and the hypercatabolic state observed in sickle cell disease (SCD).

METHODS

Plasma leptin concentration and resting energy expenditure (REE) were measured in 37 SCD patients (10 men, 12 boys 14 to 18 years-old, seven women, and eight girls 14 to 18 year-old) and in 37 age, gender and fat mass (FM) matched controls. Body composition was measured hydrostatically, REE by whole room-indirect calorimeter, and plasma leptin using an RIA kit.

RESULTS

Plasma leptin concentration and leptin normalized for body fat (ng/dL*kg FM(-1)) were significantly lower in SCD patients than in non-SCD controls (4.00+/-3.23 vs. 9.94+/-14.69, p=0.021 and 0.406+/-0.260 vs. 0.643+/-0.561, p=0.024, respectively). A positive linear association between log plasma leptin and FM was observed in both males and females, adjusting for age and SCD status. The strength of this association was greater in females compared with males (slope=0.699 and 0.382 log ng/mL per 10 kg FM, respectively; p=0.013). SCD patients on average demonstrated a higher REE, adjusting for FFM (p<0.0001). Log plasma leptin and FM were not statistically significant predictors of REE after adjustment for FFM and SCD.

CONCLUSIONS

Once corrected for body composition, mean plasma leptin concentration was significantly lower among female SCD patients than among non-SCD matched controls. Although REE was higher in SCD patients, there is no simple association between leptin and REE in SCD.