Phosphate NIMA-Related Kinase 2-Dependent Epigenetic Pathways in Dorsal Root Ganglion Neurons Mediates Paclitaxel-Induced Neuropathic Pain.

BACKGROUND: The microtubule-stabilizing drug paclitaxel (PTX) is an important chemotherapeutic agent for cancer treatment and causes peripheral neuropathy as a common side effect that substantially impacts the functional status and quality of life of patients. The mechanistic role for NIMA-related kinase 2 (NEK2) in the progression of PTX-induced neuropathic pain has not been established. METHODS: Adult male Sprague-Dawley rats intraperitoneally received PTX to induce neuropathic pain. The protein expression levels in the dorsal root ganglion (DRG) of animals were measured by biochemical analyses. Nociceptive behaviors were evaluated by von Frey tests and hot plate tests. RESULTS: PTX increased phosphorylation of the important microtubule dynamics regulator NEK2 in DRG neurons and induced profound neuropathic allodynia. PTX-activated phosphorylated NEK2 (pNEK2) increased jumonji domain-containing 3 (JMJD3) protein, a histone demethylase protein, to specifically catalyze the demethylation of the repressive histone mark H3 lysine 27 trimethylation (H3K27me3) at the Trpv1 gene, thereby enhancing transient receptor potential vanilloid subtype-1 (TRPV1) expression in DRG neurons. Moreover, the pNEK2-dependent PTX response program is regulated by enhancing p90 ribosomal S6 kinase 2 (RSK2) phosphorylation. Conversely, intrathecal injections of kaempferol (a selective RSK2 activation antagonist), NCL 00017509 (a selective NEK2 inhibitor), NEK2-targeted siRNA, GSK-J4 (a selective JMJD3 inhibitor), or capsazepine (an antagonist of TRPV1 receptor) into PTX-treated rats reversed neuropathic allodynia and restored silencing of the Trpv1 gene, suggesting the hierarchy and interaction among phosphorylated RSK2 (pRSK2), pNEK2, JMJD3, H3K27me3, and TRPV1 in the DRG neurons in PTX-induced neuropathic pain. CONCLUSIONS: pRSK2/JMJD3/H3K27me3/TRPV1 signaling in the DRG neurons plays as a key regulator for PTX therapeutic approaches.

Identification of human cytomegalovirus in tumour tissues of colorectal cancer and its association with the outcome of non-elderly patients.

Increasing evidence suggests that human cytomegalovirus (HCMV) plays an oncomodulatory role in human cancers. In colorectal cancer (CRC), presence of HCMV in tumours has been associated with a poor outcome in elderly patients. This study aimed to investigate the association between HCMV and the outcome of non-elderly patients with CRC. In tumour samples, HCMV DNA was detected by PCR. Viral transcript and protein were detected by in situ hybridization (ISH) and immunohistochemical staining (IHC), respectively. Clinical, pathological and survival data were compared between patients with HCMV-positive and -negative tumours. Quantitative reverse transcription PCR (qRT-PCR) was used to analyse the expression levels of cellular signals related to CRC progression and metastasis. Among 89 CRC non-elderly patients aged <65 years, HCMV was detected in 31 (34.8 %) tumour samples by PCR. By ISH and IHC, viral transcript and protein specifically localized to the cytoplasm of neoplastic mucosal epithelium. Outcome analysis revealed a more favourable disease-free survival (DFS) rate in patients with HCMV-positive tumours (P<0.01), specifically in patients with stage III disease. In a multivariate Cox proportional-hazard model, tumoural presence of HCMV independently predicted a higher DFS rate (hazard ratio 0.22; 95 % confidence interval 0.075-0.66, P<0.01). By qRT-PCR, the tumoural levels of interleukin-1 were relatively lower in samples positive for HCMV. The results suggest that HCMV may influence the outcome of CRC in an age-dependent manner and possibly has a dual oncomodulatory effect. How the virus interacts with the tumour microenvironment should be further studied.

Human cytomegalovirus preferentially infects the neoplastic epithelium of colorectal cancer: a quantitative and histological analysis.

BACKGROUND: It has long been suggested that human cytomegalovirus (HCMV) might be involved in human oncogenesis. However, whether HCMV was associated with colorectal cancer (CRC) was still controversial. OBJECTIVE: To clarify whether HCMV specifically infects the tumorous tissue of CRC. STUDY DESIGN: Paired tumor and adjacent non-neoplastic CRC specimens were collected from 163 patients. HCMV DNA was detected and quantified through PCR and quantitative real-time PCR. Virus location was determined by in situ hybridization (ISH) of formalin-fixed paraffin-embedded tissue sections with an HCMV-specific probe. RESULTS: By PCR, HCMV DNA was detected in 42.3% (69/163) of the tumor specimens, while only 5.6%(14/163) samples of adjacent non-neoplastic tissue were positive for HCMV (p<0.0001). Quantitative real-time PCR in 54 sample pairs revealed significantly higher viral copies in the tumor specimens than the adjacent non-neoplastic tissue specimens (p<0.001). By ISH, the nucleic acids of HCMV were detected in the cytoplasm of neoplastic epithelium. No hybridization was detected in the inflammatory infiltrates, submucosa, or other stromal tissues. CONCLUSIONS: HCMV preferentially infects the tumor epithelium of CRC. How the virus subsists in and interacts with the microenvironment of tumor epithelium of CRC should be studied.

Hyaluronic acid receptor CD44 deficiency is associated with decreased Cryptococcus neoformans brain infection.

Cryptococcus neoformans is a pathogenic yeast that can invade the brain and cause meningoencephalitis. Our previous in vitro studies suggested that the interaction between C. neoformans hyaluronic acid and human brain endothelial CD44 could be the initial step of brain invasion. In this report, we used a CD44 knock-out (KO or CD44(-/-)) mouse model to explore the importance of CD44 in C. neoformans brain invasion. Our results showed that C. neoformans-infected CD44 KO mice survived longer than the infected wild-type mice. Consistent with our in vitro results, the brain and cerebrospinal fluid fungal burden was reduced in CD44-deficient mice. Histopathological studies showed smaller and fewer cystic lesions in the brains of CD44 KO mice. Interestingly, the cystic lesions contained C. neoformans cells embedded within their polysaccharide capsule and were surrounded by host glial cells. We also found that a secondary hyaluronic acid receptor, RHAMM (receptor of hyaluronan-mediated motility), was present in the CD44 KO mice. Importantly, our studies demonstrated an in vivo blocking effect of simvastatin. These results suggest that the CD44 and RHAMM receptors function on membrane lipid rafts during invasion and that simvastatin may have a potential therapeutic role in C. neoformans infections of the brain.

Nosocomial nasal myiasis in an intubated patient.

We report a case of nasal myiasis caused by Sarcophaga spp., noted during hospitalization. A 74-year-old man was admitted with non-ST-elevation myocardial infarction. The patient underwent coronary arterial bypass surgery and was then mechanically ventilated by means of a nasotracheal tube for the next 8 days. After extubation, a total of seven maggots were retrieved from both nostrils. The larvae were removed and reared to mature flies, which were identified as Sarcophaga peregrina. From the clinical course and the fly's life cycle, it was concluded that the infestation was hospital-acquired.

Clinical characteristics of patients with Acinetobacter junii infection.

BACKGROUND AND PURPOSE: Acinetobacter junii is a human pathogen but A. junii infection is rarely reported. This study aimed to delineate the characteristics of A. junii infection. METHODS: The medical records of 34 patients who were treated at Taipei Veterans General Hospital, Taipei, Taiwan, from May 1999 to May 2007 and had A. junii isolated from sterile sites were reviewed. Isolates of A. junii were identified by using API ID 32 GN and were confirmed by analysis of the 16S-23S rRNA intergenic spacer region. RESULTS: Thirty five infections with A. junii were identified. The most common underlying conditions included prior antibiotic use (56%), central venous catheterization (50%), and malignancy (38%). Systemic inflammatory response syndrome and shock developing within 1 week were observed in 27 (77%) and 8 (23%) episodes, respectively. Eighty percent of the infectious episodes were hospital acquired. The infections were primary bacteremia (n = 32), empyema (n = 1), peritonitis (n = 1), and keratitis (n = 1). Polymicrobial infection was present in 9 episodes (26%). A. junii isolates remained susceptible to most of the tested antimicrobial agents, but the hospital-acquired isolates had higher resistance rates than the community-acquired isolates. Four patients (11.4%) died of A. junii infection despite appropriate antimicrobial therapy for 3 patients. Shock that developed within 1 week of bacteremia was associated with a poor outcome (p = 0.01). CONCLUSIONS: A. junii is an opportunistic pathogen that mainly affects patients who have had prior antimicrobial therapy, invasive procedures, or malignancy. Newly emerging infections caused by A. junii and the increasing antimicrobial resistance among hospital-acquired A. junii isolates should be monitored.

Clinical significance of Blastocystis hominis: experience from a medical center in northern Taiwan.

BACKGROUND AND PURPOSE: Blastocystis hominis is an intestinal protozoan. The pathogenic role of this organism in human beings is still controversial and has varied among reports from different geographic areas. The purpose of this study was to determine the clinical significance of B. hominis in northern Taiwan. METHODS: A total of 100 patients who had a positive B. hominis stool examination during the period April to December of 2001 were retrospectively identified from Taipei Veterans General Hospital. The demographic and clinical characteristics of these patients were reviewed from the medical records. RESULTS: All of the patients were adults. Fifty nine patients had more than one underlying diseases, including malignancies. Twenty one patients presented with fever and 10 patients had gastrointestinal symptoms, including diarrhea and/or abdominal pain. However, all of the patients had other conditions that might have contributed to the clinical presentation, and they improved without specific treatment for B. hominis. Furthermore, there were no significant differences in clinical symptoms and white blood cell count between patients with malignancy or diabetes mellitus and those without. Six patients had hypereosinophilia that could not be attributed to other causes. Among 34 patients who had a further stool examination within one year, B. hominis was undetectable in 31 patients (91.2%), despite their having no specific antiprotozoal treatment. CONCLUSIONS: The association of clinical symptoms and B. hominis could not be delineated from our study, even in immunocompromised patients. All of the patients improved without receiving any specific therapy. More studies from different areas are needed in order to delineate the clinical significance B. hominis.

The type-2 variant of human cytomegalovirus glycoprotein N (gN-2) is not the rarest in the Chinese population of Taiwan: influence of primer design.

Studies of the human cytomegalovirus (HCMV) glycoprotein N (gpUL73-gN) showed that genotypic variations exist in different geographic areas, with gN-2 unidentified in Chinese population. The purpose of this study was to determine the HCMV gN variants in the Chinese population of Taiwan. Primers were designed and a polymerase chain reaction (PCR) was carried out on the UL73 gene. The PCR products were subjected to restriction fragment length polymorphism (RFLP) analysis. The same PCR-RFLP assay was repeated using primers published previously to demonstrate the influence of primer design. Of the 48 clinical HCMV isolates, 33 were positive for PCR products by both primer sets. Fifteen were positive only by the "in-house" PCR. The distribution of gN-1, gN-2, gN-3, and gN-4 by RFLP analysis was 14:11:7:17, with one isolate positive for both gN-1 and gN-2. The published primers detected the four genotypes with the number of 14:0:2:17. The under-representation of gN-2 and gN-3 by the method published previously may be due to inappropriate primer design when re-examining the sequences. On the basis of the results of this study, gN-2 is not the rarest gN genotype in the Chinese population of Taiwan. The design of primers used for PCR-RFLP genotyping may have a great influence on the frequency distribution of HCMV genomic variants.

Risk factors for mortality in patients with Acinetobacter baumannii bloodstream infection with genotypic species identification.

BACKGROUND AND PURPOSE: Acinetobacter baumannii is an increasingly common nosocomial infection with a high mortality rate. Identification of predictor factors of mortality from A. baumannii infection is important for the implementation of therapeutic management for patients with higher risk. However, many studies have reported data for Acinetobacter calcoaceticus-A. baumannii complex, which might lead to an uncertainty of results. In this study, we aimed to identify the predictive factors for mortality of patients infected with true A. baumannii that had been precisely identified by genotypic methodology. METHODS: Sixty seven patients with documented A. baumannii bacteremia were identified from a medical center in northern Taiwan during the period between February 1998 and February 2001. The patients' medical records were retrospectively reviewed. RESULTS: The risk factors associated with mortality in patients with A. baumannii bacteremia were underlying disease with malignancy, end-stage renal disease, and inappropriate antibiotic therapy. Laboratory variables, such as creatinine level, were also associated with poor prognosis by multivariate analysis. CONCLUSIONS: Increased serum creatinine level, malignancy and inappropriate therapy within 3 days were related to increased mortality in patients with A. baumannii bloodstream infection. Physicians should be aware of patients with poor prognostic factors and initiate prompt strategies, including appropriate antimicrobial therapy, in order to reduce mortality.