BACKGROUND

Although whole lung irradiation (WLI) is used to treat pulmonary metastases of pediatric solid malignancies, few studies have addressed its long-term pulmonary consequences.

METHODS

We conducted a retrospective study of longitudinal changes in 171 pulmonary function tests (PFTs) and their relationship with clinical features in 48 survivors of pediatric malignant solid tumors treated with WLI.

RESULTS

Although active respiratory symptoms were seen in only 9 (18.8%) patients, abnormalities in forced vital capacity (FVC; 58.3%), forced expiratory volume in 1 second (FEV1; 64.6%), total lung capacity (TLC; 72.9%), and diffusion capacity of carbon monoxide corrected for hemoglobin (DLCOcorr; 70.8%) were common. At a median follow-up of 9.7 years after WLI, FVC, FEV1, and TLC significantly declined longitudinally (P = .04, .03, and .02, respectively). Focal pulmonary boost irradiation was significantly associated with abnormal FEV1/FVC (P = .03), forced expiratory flow between 25% and 75% forced vital capacity (FEF25%–75%; P = .005), residual volume (RV; P = .005), and RV/TLC (P = .002). Ten patients had baseline PFTs, and FVC, FEV1, TLC and DLCOcorr worsened immediately after radiation, followed by transient improvement but subsequent decline. Thirteen of 32 (40.6%) patients over the age of 18 were smokers.

CONCLUSIONS

Pulmonary dysfunction, especially in lung volumes, was prevalent after WLI and worsened over time although most patients were asymptomatic. Boost irradiation impaired pulmonary function, and a significant proportion of patients were smokers. Further studies are planned to assess the predictors and clinical consequences of progressive PFT abnormalities and to evaluate educational interventions.

An isolated strain Streptomyces sp. HJC-D1 was applied to inhibit the growth of cyanobacterium Microcystis aeruginosa FACHB-905. The effect of Streptomyces sp. HJC-D1 culture broth on the cell integrity and physiological characteristics of M. aeruginosa FACHB-905 was investigated using the flow cytometry (FCM), enzyme activity and transmission electron microscopy (TEM) methods. Results showed that the growth of M. aeruginosa FACHB-905 was significantly inhibited, and the percentage of live cells depended on the culture broth concentration and exposure time. The activities of antioxidant enzymes including superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) increased with exposure concentration and exposure time, and the significant increase of reactive oxygen species (ROS) led to the disruption of the subcellular structure of M. aeruginosa FACHB-905, and caused the increase of malondialdehyde (MDA). Furthermore, TEM observation suggested the presence of three stages (cell breakage, organelle release and cell death) for the cyanobactericidal process of Streptomyces sp. HJC-D1. Therefore, Streptomyces sp. HJC-D1 not only affected antioxidant enzyme activities and ROS level, but also destroyed the subcellular structure of M. aeruginosa FACHB-905, demonstrating excellent cyanobactericidal properties.

Adenomatous polyposis coli (APC) regulates cell-cell adhesion and cell migration through activating the APC-stimulated guanine nucleotide-exchange factor (GEF; Asef), which is usually autoinhibited through the binding between its Src homology 3 (SH3) and Dbl homology (DH) domains. The APC-activated Asef stimulates the small GTPase Cdc42, which leads to decreased cell-cell adherence and enhanced cell migration. In colorectal cancers, truncated APC constitutively activates Asef and promotes cancer cell migration and angiogenesis. Here, we report crystal structures of the human APC/Asef complex. We find that the armadillo repeat domain of APC uses a highly conserved surface groove to recognize the APC-binding region (ABR) of Asef, conformation of which changes dramatically upon binding to APC. Key residues on APC and Asef for the complex formation were mutated and their importance was demonstrated by binding and activity assays. Structural superimposition of the APC/Asef complex with autoinhibited Asef suggests that the binding between APC and Asef might create a steric clash between Asef-DH domain and APC, which possibly leads to a conformational change in Asef that stimulates its GEF activity. Our structures thus elucidate the molecular mechanism of Asef recognition by APC, as well as provide a potential target for pharmaceutical intervention against cancers.

Purpose

Many Childhood Cancer Survivor Study (CCSS) participants are at increased risk for obesity. The etiology of their obesity is likely multifactorial but not well understood.

Patients and Methods

We evaluated the potential contribution of demographic, lifestyle, treatment, and intrapersonal factors and self-reported pharmaceutical use to obesity (body mass index ≥ 30 kg/m2) among 9,284 adult (> 18 years of age) CCSS participants. Independent predictors were identified using multivariable regression models. Interrelationships were determined using structural equation modeling (SEM).

Results

Independent risk factors for obesity included cancer diagnosed at 5 to 9 years of age (relative risk [RR], 1.12; 95% CI, 1.01 to 1.24; P = .03), abnormal Short Form–36 physical function (RR, 1.19; 95% CI, 1.06 to 1.33; P < .001), hypothalamic/pituitary radiation doses of 20 to 30 Gy (RR, 1.17; 95% CI, 1.05 to 1.30; P = .01), and paroxetine use (RR, 1.29; 95% CI, 1.08 to 1.54; P = .01). Meeting US Centers for Disease Control and Prevention guidelines for vigorous physical activity (RR, 0.90; 95% CI, 0.82 to 0.97; P = .01) and a medium amount of anxiety (RR, 0.86; 95% CI, 0.75 to 0.99; P = .04) reduced the risk of obesity. Results of SEM (N = 8,244; comparative fit index = 0.999; Tucker Lewis index = 0.999; root mean square error of approximation = 0.014; weighted root mean square residual = 0.749) described the hierarchical impact of the direct predictors, moderators, and mediators of obesity.

Conclusion

Treatment, lifestyle, and intrapersonal factors, as well as the use of specific antidepressants, may contribute to obesity among survivors. A multifaceted intervention, including alternative drug and other therapies for depression and anxiety, may be required to reduce risk.

Background

Adult survivors of childhood cancer and their siblings are compared on one of the most salient developmental milestones of adulthood, the ability to live independently.

Procedure

Adult survivors of childhood cancers (n=6,047) and siblings (n=2,326), all 25 years of age and older, completed a long-term follow-up questionnaire that assessed adaptive, neurocognitive, and psychological functioning, as well as demographic and health status. Multivariable logistic regression analyses and structural equation modeling (SEM) were used to identify predictors of independent living.

Results

Compared to siblings (n=206, 8.7%), survivors (n=1063; 17.7%) were more than twice as likely to live dependently (OR 2.07; 95% confidence interval [CI] 1.77–2.42). Survivors diagnosed with CNS tumors (OR 0.13, 95% CI 0.10–0.18) or leukemia (OR 0.29, 95% CI 0.23–0.27) were significantly less likely to live independently compared to those diagnosed with Hodgkin Lymphoma. Other risk factors for reduced independent living included cranial radiation (≤24Gy OR 0.76, 95% CI 0.62–0.93; >24Gy OR 0.31, 95% CI 0.24–0.41), use of neuroleptic, anticonvulsant, or psychostimulant medication (OR 0.32, 95% CI 0.24–0.43), attention and processing speed problems (OR 0.58, 95% CI 0.47–0.71), poor physical functioning (OR 0.49, 95% CI 0.38–0.63), depression (OR 0.68, 95% CI 0.53–0.88), and racial/ethnic minority status (OR 0.39, 95% CI 0.30–0.51). SEM demonstrated that neurocognitive functioning had both direct effects on independent living status, and indirect effects through use of neurologically-directed medication, depression, and poor mental health.

Conclusion

Adult survivors of childhood cancer who experience neurocognitive, psychological or physical late effects are less likely to live independently as adults.

Background

Survivors of childhood acute lymphoblastic leukemia (ALL) sometimes have clinical features that suggest Attention-Deficit/Hyperactivity Disorder (ADHD), though few studies have examined specific symptoms in survivors.

Procedure

Long-term survivors of childhood ALL (n=161) received a neurological examination, while parents completed rating scales to establish formal criteria for ADHD. Symptom profiles were generated and compared across demographic and treatment characteristics, as well as medical tests associated with brain pathology.

Results

Prevalence rates of ADHD were similar in survivors (10.5%) compared to those reported in the general population (7–10%). However, 25.5% of survivors reported symptoms that impair functioning in multiple settings, with attention problems being most common. These symptoms were associated with cranial radiation therapy (CRT) (mean inattentive symptoms [SD] = 3.6 [3.19] for group treated with CRT vs. 1.6 [2.40] for non-CRT group, p=0.0006), and survivors who demonstrated impaired anti-saccades during the neurologic exam (mean inattentive symptoms [SD] = 3.4 [3.29] for those with impaired anti-saccades vs. 1.4 [2.41] for those with normal anti-saccades; p = 0.0004).

Conclusions

The presence of a neurologically-based phenotype of attention problems in survivors of leukemia that is not fully captured by the syndrome of ADHD suggests that treatments specific to childhood ALL should be explored.

AIM: To compare fluoroscopic, endoscopic and guide wire assistance with ultraslim gastroscopy for placement of nasojejunal feeding tubes.

METHODS: The information regarding nasojejunal tube placement procedures was retrieved using the gastrointestinal tract database at Tongji Hospital affiliated to Tongji Medical College. Records from 81 patients who underwent nasojejunal tubes placement by different techniques between 2004 and 2011 were reviewed for procedure success and tube-related outcomes.

RESULTS: Nasojejunal feeding tubes were successfully placed in 78 (96.3%) of 81 patients. The success rate by fluoroscopy was 92% (23 of 25), by endoscopic technique 96.3% (26 of 27), and by guide wire assistance (whether via transnasal or transoral insertion) 100% (23/23, 6/6). The average time for successful placement was 14.9 ± 2.9 min for fluoroscopic placement, 14.8 ± 4.9 min for endoscopic placement, 11.1 ± 2.2 min for guide wire assistance with transnasal gastroscopic placement, and 14.7 ± 1.2 min for transoral gastroscopic placement. Statistically, the duration for the third method was significantly different (P < 0.05) compared with the other three methods. Transnasal placement over a guidewire was significantly faster (P < 0.05) than any of the other approaches.

CONCLUSION: Guide wire assistance with transnasal insertion of nasojejunal feeding tubes represents a safe, quick and effective method for providing enteral nutrition.

Summary

The coordination of signalling pathways within the cell is vital for normal human development and post-natal tissue homeostasis. Gene expression and function is therefore tightly controlled at a number of levels. We investigated the role that post-translational modifications play during human hepatocyte differentiation. In particular, we examined the role of the small ubiquitin-like modifier (SUMO) proteins in this process. We used a human embryonic stem cell (hESC)-based model of hepatocyte differentiation to follow changes in protein SUMOylation. Moreover, to confirm the results derived from our cell-based system, we performed in vitro conjugation assays to characterise SUMO modification of a key liver-enriched transcription factor, HNF4α. Our analyses indicate that SUMOylation plays an important role during hepatocellular differentiation and this is mediated, in part, through regulation of the stability of HNF4α in a ubiquitin-dependent manner. Our study provides a better understanding of SUMOylation during human hepatocyte differentiation and maturation. Moreover, we believe the results will stimulate interest in the differentiation and phenotypic regulation of other somatic cell types.

SUMMARY

Tight regulation of NF-κB signaling is essential for innate and adaptive immune responses, yet the molecular mechanisms responsible for its negative regulation are not completely understood. Here we report that NLRX1, a NOD-like receptor family member, negatively regulates Toll-like receptor-mediated NF-κB activation. NLRX1 interacts with TRAF6 or IκB kinase (IKK) in an activation signal-dependent fashion. Upon LPS stimulation, NLRX1 is rapidly ubiquitinated, disassociates from TRAF6 and then binds to the IKK complex, resulting in inhibition of IKKα/β phosphorylation and NF-κB activation. Knockdown of NLRX1 in various cell types markedly enhances IKK phosphorylation and the production of NF-κB-responsive cytokines after LPS stimulation. We further provide in vivo evidence that NLRX1 knockdown in mice markedly enhances susceptibility to LPS-induced septic shock and plasma IL-6 level. Our study identifies a previously unrecognized role for NLRX1 in the negative regulation of TLR-induced NF-κB activation by dynamically interacting with TRAF6 and the IKK complex.

Introduction

Since the late 1970's, time-space clusters of sudden unexplained death (SUD) in northwest Yunnan, China have alarmed the public and health authorities. From 2006–2009, we initiated enhanced surveillance for SUD to identify a cause, and we warned villagers to avoid eating unfamiliar mushrooms.

Methods

We established surveillance for SUD, defined as follows: sudden onset of serious, unexplained physical impairment followed by death in <24 hours. A mild case was onset of any illness in a member of the family or close socially related group of a SUD victim within 1 week of a SUD. We interviewed witnesses of SUD and mild case-persons to identify exposures to potentially toxic substances. We tested blood from mild cases, villagers, and for standard biochemical, enzyme, and electrolyte markers of disease.

Results

We identified 33 SUD, a 73% decline from 2002–2005, distributed among 21 villages of 11 counties. We found a previously undescribed mushroom, Trogia venenata, was eaten by 5 of 7 families with SUD clusters compared to 0 of 31 other control-families from the same villages. In T. venenata–exposed persons SUD was characterized by sudden loss of consciousness during normal activities. This mushroom grew nearby 75% of 61 villages that had time-space SUD clusters from 1975 to 2009 compared to 17% of 18 villages with only single SUD (p<0.001, Fisher's exact test).

Discussion

Epidemiologic data has implicated T. venenata as a probable cause of clusters of SUD in northwestern Yunnan Province. Warnings to villagers about eating this mushroom should continue.

Human stem cells are scalable cell populations capable of cellular differentiation. This makes them a very attractive in vitro cellular resource and in theory provides unlimited amounts of primary cells. Such an approach has the potential to improve our understanding of human biology and treating disease. In the future it may be possible to deploy novel stem cell-based approaches to treat human liver diseases. In recent years, efficient hepatic differentiation from human stem cells has been achieved by several research groups including our own. In this review we provide an overview of the field and discuss the future potential and limitations of stem cell technology.

Most Sphingomonas species synthesize the yellow carotenoid nostoxanthin. However, the carotenoid biosynthetic pathway of these species remains unclear. In this study, we cloned and characterized a carotenoid biosynthesis gene cluster containing four carotenogenic genes (crtG, crtY, crtI and crtB) and a β-carotene hydroxylase gene (crtZ) located outside the cluster, from the gellan-gum producing bacterium Sphingomonas elodea ATCC 31461. Each of these genes was inactivated, and the biochemical function of each gene was confirmed based on chromatographic and spectroscopic analysis of the intermediates accumulated in the knockout mutants. Moreover, the crtG gene encoding the 2,2′-β-hydroxylase and the crtZ gene encoding the β-carotene hydroxylase, both responsible for hydroxylation of β-carotene, were confirmed by complementation studies using Escherichia coli producing different carotenoids. Expression of crtG in zeaxanthin and β-carotene accumulating E. coli cells resulted in the formation of nostoxanthin and 2,2′-dihydroxy-β-carotene, respectively. Based on these results, a biochemical pathway for synthesis of nostoxanthin in S. elodea ATCC 31461 is proposed.

Background

Response gene to complement-32 (RGC-32) is comprehensively expressed in many kinds of tissues and has been reported to be expressed abnormally in different kinds of human tumors. However, the role of RGC-32 in cancer remains controversial and no reports have described the effect of RGC-32 in pancreatic cancer. The present study investigated the expression of RGC-32 in pancreatic cancer tissues and explored the role of RGC-32 in transforming growth factor-beta (TGF-β)-induced epithelial-mesenchymal transition (EMT) in human pancreatic cancer cell line BxPC-3.

Methods

Immunohistochemical staining of RGC-32 and E-cadherin was performed on specimens from 42 patients with pancreatic cancer, 12 with chronic pancreatitis and 8 with normal pancreas. To evaluate the role of RGC-32 in TGF-β-induced EMT in pancreatic cancer cells, BxPC-3 cells were treated with TGF-β1, and RGC-32 siRNA silencing and gene overexpression were performed as well. The mRNA expression and protein expression of RGC-32 and EMT markers such E-cadherin and vimentin were determined by quantitative reverse transcription-PCR (qRT-PCR) and western blot respectively. Finally, migration ability of BxPC-3 cells treated with TGF-β and RGC-32 siRNA transfection was examined by transwell cell migration assay.

Results

We found stronger expression of RGC-32 and higher abnormal expression rate of E-cadherin in pancreatic cancer tissues than those in chronic pancreatitis tissues and normal pancreatic tissues. Immunohistochemical analysis revealed that both RGC-32 positive expression and E-cadherin abnormal expression in pancreatic cancer were correlated with lymph node metastasis and TNM staging. In addition, a significant and positive correlation was found between positive expression of RGC-32 and abnormal expression of E-cadherin. Furthermore, in vitro, we found sustained TGF-β stimuli induced EMT and up-regulated RGC-32 expression in BxPC-3 cells. By means of siRNA silencing and gene overexpression, we further demonstrated that RGC-32 mediated TGF-β-induced EMT and migration in BxPC-3 cells.

Conclusions

The results above indicated that RGC-32 might be a novel metastasis promoting gene in pancreatic cancer and it enhances metastatic phenotype by mediating TGF-β-induced EMT in human pancreatic cancer cell line BxPC-3.

Background

The recent increase in bacterial resistance to antibiotics has promoted the exploration of novel antibacterial materials. As a result, many researchers are undertaking work to identify new lantibiotics because of their potent antimicrobial activities. The objective of this study was to provide details of a lantibiotic-like gene cluster in Paenibacillus elgii B69 and to produce the antibacterial substances coded by this gene cluster based on culture screening.

Results

Analysis of the P. elgii B69 genome sequence revealed the presence of a lantibiotic-like gene cluster composed of five open reading frames (elgT1, elgC, elgT2, elgB, and elgA). Screening of culture extracts for active substances possessing the predicted properties of the encoded product led to the isolation of four novel peptides (elgicins AI, AII, B, and C) with a broad inhibitory spectrum. The molecular weights of these peptides were 4536, 4593, 4706, and 4820 Da, respectively. The N-terminal sequence of elgicin B was Leu-Gly-Asp-Tyr, which corresponded to the partial sequence of the peptide ElgA encoded by elgA. Edman degradation suggested that the product elgicin B is derived from ElgA. By correlating the results of electrospray ionization-mass spectrometry analyses of elgicins AI, AII, and C, these peptides are deduced to have originated from the same precursor, ElgA.

Conclusions

A novel lantibiotic-like gene cluster was shown to be present in P. elgii B69. Four new lantibiotics with a broad inhibitory spectrum were isolated, and these appear to be promising antibacterial agents.

Background

Infections with methicillin-resistant Staphylococcus aureus (MRSA), in community-settings, especially with strains carrying the Panton-Valentine Leukocidin (PVL) genes, have increased markedly in recent years. Colonization with S.aureus is a risk factor for infection. However, there are few studies that examine colonization and infection with PVL-positive strains of MRSA in cancer patients.

Procedure

The epidemiology of colonization and infection with MRSA was studied in children with cancer during two time periods: 2000/2001 and 2006/2007. PVL genes were screened and spa typing performed on the isolates.

Results

The prevalence of colonization with MRSA increased from 0.6% in 2000/2001 to 2.9% in 2006/2007(p=0.0003). MRSA colonization at admission was associated with infection (p<0.0001; RR 38.32; 95% CI: 23.36 - 62.84). The prevalence of infection increased from 0.99% in 2000/2001 to 3.78% in 2006-2007 (p=0.0002). Of the 32 colonized patients, 18 (56%) had infection. None of the 14 colonized but non-infected patients had dual colonization of nares and rectum, while 8 of the 18 infected patients had colonization of both of these sites (p=0.004). Ten patients (31%) were colonized with PVL-positive strains. Patients colonized with PVL-positive strains were more likely to be colonized both in the nares and rectum (p=0.005), and more likely to have infection (p=0.001). Recurrent MRSA infections were seen in 22% of patients.

Conclusion

An increasing prevalence of colonization with MRSA was observed in children with cancer at our institution. Colonization with MRSA especially with PVL-positive strains was associated with infection.

OBJECTIVE

To investigate the association between neck circumference and central obesity, overweight, and metabolic syndrome in Chinese individuals with type 2 diabetes.

RESEARCH DESIGN AND METHODS

A total of 3,182 diabetic subjects (aged 20–80 years) were recruited from 15 community health centers in Beijing using a multistage random sampling approach.

RESULTS

Receiver operating characteristic analysis showed that the area under the curve for neck circumference and central obesity was 0.77 for men and 0.75 for women (P < 0.001). Furthermore, a neck circumference of ≥38 cm for men and ≥35 cm for women was the best cutoff point for determining overweight subjects. A neck circumference of ≥39 cm for men and ≥35 cm for women was the best cutoff point to determine subjects with metabolic syndrome.

CONCLUSIONS

In the present study, neck circumference is positively related with BMI, waist circumference, and metabolic syndrome in Chinese individuals with type 2 diabetes.

Summary

Stringent control of the NF-κB and type I interferon pathways is critical to effective host immune responses, yet the molecular mechanisms that negatively regulate these pathways are poorly understood. Here we show that NLRC5, a member of the NOD-like protein family, can inhibit the IKK complex and RIG-I/MDA5 function. NLRC5 strongly inhibited NF-κB-dependent responses by interacting with IKKα/IKKβ and blocking their phosphorylation. It also interacted with RIG-I and MDA5, but not with MAVS, to potently inhibit RIG-I-like receptor-mediated type I interferon responses. Consistent with these observations, NLRC5-specific siRNA knockdown not only enhanced the activation of NF-κB and its responsive genes, TNF-α and IL-6, but also promoted type I interferon signaling and antiviral immunity. Our findings identify NLRC5 as a key negative regulator that blocks two central components of the NF-κB and type I interferon pathways, and hence is a pivotal element in the homeostatic control of the innate immune system.

Previous studies have identified several dysregulated microRNAs in esophageal squamous cell carcinoma (ESCC); however, to date there are no ex vivo analyses comparing expression levels of these regulatory molecules in esophageal squamous cell tumors versus patient-matched normal epithelium. We describe here a technical strategy to evaluate microRNAs in normal esophageal basal cells (NB), normal esophageal differentiated cells (ND), and tumor cells (T). Laser capture microdissection was used to procure target populations from five cases and 18 ESCC-associated microRNAs were measured by RT-qPCR. Five microRNAs (miR-25, miR-106b, miR-21, miR-203, and miR-145) demonstrated consistent differential expression in at least one of the three comparisons: T vs. NB, T vs. ND, or NB vs. ND. The potential regulatory role of the microRNAs in ESCC was further evaluated by correlating their expression with a matched mRNA dataset, which included the same five cases and cell populations. In conclusion, the present work demonstrates the feasibility of studying microRNA levels in precisely dissected cell populations from clinical samples, and sheds light on the molecular mechanisms associated with ESCC.

The nuclear receptor pregnane X receptor (PXR) is activated by a range of xenochemicals, including chemotherapeutic drugs, and has been suggested to play a role in the development of tumor cell resistance to anticancer drugs. PXR also has been implicated as a regulator of the growth and apoptosis of colon tumors. Here, we have used a xenograft model of colon cancer to define a molecular mechanism that might underlie PXR-driven colon tumor growth and malignancy. Activation of PXR was found to be sufficient to enhance the neoplastic characteristics, including cell growth, invasion, and metastasis, of both human colon tumor cell lines and primary human colon cancer tissue xenografted into immunodeficient mice. Furthermore, we were able to show that this PXR-mediated phenotype required FGF19 signaling. PXR bound to the FGF19 promoter in both human colon tumor cells and “normal” intestinal crypt cells. However, while both cell types proliferated in response to PXR ligands, the FGF19 promoter was activated by PXR only in cancer cells. Taken together, these data indicate that colon cancer growth in the presence of a specific PXR ligand results from tumor-specific induction of FGF19. These observations may lead to improved therapeutic regimens for colon carcinomas.

A major goal of tumor suppressor research is to neutralize the tumorigenic effects of their loss. Since loss of pRb does not induce tumorigenesis in many types of cells, natural mechanisms may neutralize the tumorigenic effects of pRb loss in these cells. For susceptible cells, neutralizing the tumorigenic effects of pRb loss could logically be achieved by correcting the deregulated activities of pRb targets to render pRb-deficient cells less abnormal. This line of research has unexpectedly revealed that knocking out the pRb target Skp2 did not render Rb1 deficient cells less abnormal but, rather, induced apoptosis in them, thereby completely blocking tumorigenesis in Rb1+/- mice and after targeted deletion of Rb1 in pituitary intermediate lobe (IL). Skp2 is a substrate-recruiting component of the SCFSkp2 E3 biquitin ligase; one of its substrates is Thr187-phosphorylated p27Kip1. A p27T187A knockin (KI) mutation phenocopied Skp2 knockout (KO) in inducing apoptosis following Rb1 loss. Thus, Skp2 KO or p27T187A KI are synthetic lethal with pRb inactivation. Since homozygous p27T187A KI mutations show no adverse effects in mice, inhibiting p27T187 phosphorylation or p27T187p ubiquitination could be a highly therapeutic and minimally toxic intervention strategy for pRb deficiency-induced tumorigenesis.

Previous studies have identified several dysregulated microRNAs in esophageal squamous cell carcinoma (ESCC); however, to date there are no ex vivo analyses comparing expression levels of these regulatory molecules in esophageal squamous cell tumors versus patient-matched normal epithelium. We describe here a technical strategy to evaluate microRNAs in normal esophageal basal cells (NB), normal esophageal differentiated cells (ND), and tumor cells (T). Laser capture microdissection was used to procure target populations from five cases and 18 ESCC-associated microRNAs were measured by RT-qPCR. Five microRNAs (miR-25, miR-106b, miR-21, miR-203, and miR-145) demonstrated consistent differential expression in at least one of the three comparisons: T vs. NB, T vs. ND, or NB vs. ND. The potential regulatory role of the microRNAs in ESCC was further evaluated by correlating their expression with a matched mRNA dataset, which included the same five cases and cell populations. In conclusion, the present work demonstrates the feasibility of studying microRNA levels in precisely dissected cell populations from clinical samples, and sheds light on the molecular mechanisms associated with ESCC.

Background

New strains of methicillin-resistant Staphylococcus aureus (MRSA) which frequently carry the Panton–Valentine leukocidin (PVL) genes have been recognized to cause invasive infections in otherwise healthy children and adults. However, the epidemiology of PVL-positive MRSA infections has not been described in children or adults with cancer.

Procedure

The epidemiology of MRSA infections in patients with cancer was retrospectively studied from 2000 to 2007. Molecular typing was performed by polymerase chain reaction (PCR) for the detection of the PVL genes. Staphylococcus cassette chromosome (SCC) mec and spa typing was performed on all PVL-positive isolates.

Results

A total of 88 MRSA isolates from clinically distinct infectious episodes were collected from 88 patients with cancer during the 8-year study period. Infections were predominant in the skin and soft tissues (SSTI; P =0.0003). PVL-positive isolates, bearing the type IV SCCmec element, encoding the gene for methicillin resistance, increased significantly during this period (P =0.043) and comprised 35 of 88 (40%) MRSA isolates. Of these 35 isolates, 32 belonged to spa type 8 and were USA300 genotype. Patients infected with PVL-positive strains did not have more SSTI (P =0.166) or bacteremia (P =0.510) as compared to patients with PVL-negative strains. A greater percentage of PVL-positive isolates were susceptible to ciprofloxacin (P =0.006).

Conclusions

PVL-positive MRSA infections are not associated with a higher morbidity as compared to PVL-negative MRSA infections in children with cancer.

Abstract

The epidemiology of methicillin-resistant Staphylococcus aureus (MRSA) infections, in particular with Panton-Valentine leukocidin (PVL)-positive strains, has not been well characterized in children and young adults with HIV infection. It is not known if PVL-positive strains of MRSA cause an increased morbidity in this population compared to PVL-negative strains. The purpose of this study was to retrospectively analyze the epidemiology of PVL-positive and PVL-negative MRSA infections in children and young adults with HIV from 2000 to 2007. Molecular typing was performed by polymerase chain reaction (PCR) for detection of the PVL genes. Staphylococcus Cassette Chromosome (SCC) mec and spa typing were performed on all PVL-positive isolates. The number of HIV patients with MRSA infection increased significantly between 2000 and 2007 (p = 0.0015). Twenty seven (87%) of the 31 MRSA isolates were from skin and soft tissue infections (SSTI). Clindamycin resistance was observed in 19% of the MRSA isolates. PVL-positive isolates bearing the type IV SCC mec element comprised 16 of 31 (52%) MRSA isolates. All the PVL-positive isolates belonged to the USA300 pulsed-field type. There was no difference in the mean CD4 count and HIV viral load between patients with PVL-positive and PVL-negative MRSA infections. PVL-positive MRSA infections were associated with more SSTI (p = 0.043) but not with increased morbidity or a higher risk of complications compared to PVL-negative MRSA infections in children and young adults with HIV.