Indigenous Microbiota Protects against Inflammation-Induced Osteonecrosis.

Medication-related osteonecrosis of the jaw (MRONJ) is a rare intraoral lesion that occurs in patients undergoing long-term and/or high-dose therapy with nitrogen-containing bisphosphonates, a RANKL inhibitor, antiangiogenic agents, or mTOR inhibitors. The presence of pathogenic bacteria is highly associated with advanced stages of MRONJ lesions; however, the exact role of indigenous microbes in MRONJ development is unknown. Here, we report that the normal oral flora in mice protects against inflammation-induced osteonecrosis. In mice that developed osteonecrosis following tooth extraction, there was increased bacterial infiltration when compared with healed controls. Antibiotic-mediated oral dysbiosis led to a local inhibition of bone resorption in the presence of ligature-induced periodontitis (LIP). There was no significant difference in empty lacunae, necrotic bone formation, osteoclast number, and surface area in antibiotic-treated as compared with conventionally colonized mice following extraction of healthy teeth after zoledronic acid infusions. However, extraction of LIP teeth led to increased empty lacunae, necrotic bone, and osteoclast surface area in antibiotic- and zoledronic acid-treated mice as compared with conventionally colonized mice. Our findings suggest that the presence of the indigenous microbiota protects against LIP-induced osteonecrosis.

Prognostic significance of genetic biomarkers in isocitrate dehydrogenase-wild-type lower-grade glioma: the need to further stratify this tumor entity - a meta-analysis.

The clinical outcomes of isocitrate dehydrogenase-wild-type (IDH-wt) lower-grade glioma (LGG) have been the subject of debate for some time. In this meta-analysis, we aimed to assess the prognostic values of several known genetic markers (e.g. TERT promoter mutation, H3F3A mutation, CDKN2A loss) in this tumor group. Four electronic databases, including PubMed, Scopus, Web of Science and Virtual Health Library, were searched for relevant articles. Pooled hazard ratio (HR) and corresponding 95% confidence interval (CI) for overall survival were calculated using a random-effect model weighted by an inverse variance method. A total of 11 studies were finally selected from 2274 articles for meta-analyses. Several genetic alterations were demonstrated to have a negative impact on prognosis of IDH-wt LGGs, specifically TERT promoter mutation (HR, 1.96; 95% CI, 1.42-2.70), H3F3A mutation (HR, 3.21; 95% CI, 1.86-5.55) and EGFR amplification (HR, 1.67; 95% CI, 1.02-2.74). However, CDKN loss, ATRX mutation and coexisting gain of chromosome 7/loss of chromosome 10 showed no clinical significance in this glioma entity. Our study results demonstrated that IDH-wt LGGs are heterogeneous in clinical outcome and not all tumors have a poor prognosis. The presence of TERT promoter mutation, H3F3A mutation and EGFR amplification showed negative prognostic impacts in this tumor entity. These genetic events can be used to better stratify patient outcomes.

Heterogeneous transgene expression in the retinas of the TH-RFP, TH-Cre, TH-BAC-Cre and DAT-Cre mouse lines.

Transgenic mouse lines are essential tools for understanding the connectivity, physiology and function of neuronal circuits, including those in the retina. This report compares transgene expression in the retina of a tyrosine hydroxylase (TH)-red fluorescent protein (RFP) mouse line with three catecholamine-related Cre recombinase mouse lines [TH-bacterial artificial chromosome (BAC)-, TH-, and dopamine transporter (DAT)-Cre] that were crossed with a ROSA26-tdTomato reporter line. Retinas were evaluated and immunostained with commonly used antibodies including those directed to TH, GABA and glycine to characterize the RFP or tdTomato fluorescent-labeled amacrine cells, and an antibody directed to RNA-binding protein with multiple splicing to identify ganglion cells. In TH-RFP retinas, types 1 and 2 dopamine (DA) amacrine cells were identified by their characteristic cellular morphology and type 1 DA cells by their expression of TH immunoreactivity. In the TH-BAC-, TH-, and DAT-tdTomato retinas, less than 1%, ∼ 6%, and 0%, respectively, of the fluorescent cells were the expected type 1 DA amacrine cells. Instead, in the TH-BAC-tdTomato retinas, fluorescently labeled AII amacrine cells were predominant, with some medium diameter ganglion cells. In TH-tdTomato retinas, fluorescence was in multiple neurochemical amacrine cell types, including four types of polyaxonal amacrine cells. In DAT-tdTomato retinas, fluorescence was in GABA immunoreactive amacrine cells, including two types of bistratified and two types of monostratified amacrine cells. Although each of the Cre lines was generated with the intent to specifically label DA cells, our findings show a cellular diversity in Cre expression in the adult retina and indicate the importance of careful characterization of transgene labeling patterns. These mouse lines with their distinctive cellular labeling patterns will be useful tools for future studies of retinal function and visual processing.

Hosts as ecological traps for the vector of Lyme disease.

Vectors of infectious diseases are generally thought to be regulated by abiotic conditions such as climate or the availability of specific hosts or habitats. In this study we tested whether blacklegged ticks, the vectors of Lyme disease, granulocytic anaplasmosis and babesiosis can be regulated by the species of vertebrate hosts on which they obligately feed. By subjecting field-caught hosts to parasitism by larval blacklegged ticks, we found that some host species (e.g. opossums, squirrels) that are abundantly parasitized in nature kill 83-96% of the ticks that attempt to attach and feed, while other species are more permissive of tick feeding. Given natural tick burdens we document on these hosts, we show that some hosts can kill thousands of ticks per hectare. These results indicate that the abundance of tick vectors can be regulated by the identity of the hosts upon which these vectors feed. By simulating the removal of hosts from intact communities using empirical models, we show that the loss of biodiversity may exacerbate disease risk by increasing both vector numbers and vector infection rates with a zoonotic pathogen.

CT of small-bowel obstruction in children: sensitivity and specificity.

UNLABELLED: OBJECTIVE.:The aim of this study was to determine the sensitivity, specificity, and accuracy of CT in the diagnosis of small-bowel obstruction in children. MATERIALS AND METHODS: The CT scans of 30 children with surgically proven small-bowel obstruction, 22 children with ileus, and 29 children who served as controls were retrospectively reviewed by two of four interpreters who were unaware of the children's final diagnoses. Causes of obstruction in the patients included 19 adhesions, six cases of volvulus, five intussusceptions, four strictures, and two cases each of internal hernia and abscess. Eight obstructions had multiple causes. The CT scans were evaluated for the presence of small-bowel obstruction using a scale with five degrees of confidence. In cases of discrepancy of more than one level of certainty, a third interpreter was consulted. Criteria for small-bowel obstruction included a discrepancy in caliber between the proximal dilated and the more distal small bowels or generalized small-bowel dilatation (>2.5 cm) in the presence of a collapsed colon. An interpreter's rating that an obstruction was either present or probable was considered a positive finding; a rating indicating that the interpreter was not sure whether an obstruction was present or believed that an obstruction was not probable or saw normal anatomic structures was considered a negative finding for small-bowel obstruction. The cause and level of obstruction also were recorded. RESULTS: There were 26 true-positive (87%) and four false-negative (13%) interpretations for small-bowel obstruction. Among the interpretations of scans of patients with ileus, 68% were true-negative and 32% were false-positive interpretations for small-bowel obstruction. Among the control group, there were no false-positive readings. Sensitivity of CT was 87%, specificity was 86%, and accuracy was 86%. In the scans of children 2 years and younger, CT had a sensitivity of 100% and specificity of 0%. Of the patients with surgically confirmed levels of obstruction, the correct level of obstruction was described by both interpreters in 12 (86%) of 14 scans. The causes of obstruction were correctly identified in 14 (47%) of 30 scans. CONCLUSION: CT is both sensitive and specific for use in diagnosing small-bowel obstruction in children, especially in children older than 2 years.

Mechanism of repression of squamous differentiation marker, SPRR1B, in malignant bronchial epithelial cells: role of critical TRE-sites and its transacting factors.

The overexpression of SPRR1B in bronchial epithelium is a marker for early metaplastic changes and the loss of its expression is associated with an irreversible malignant transformation. In the present study, we have used a model system consisting of normal and malignant bronchial epithelial (BE) cells to elucidate the differential transcriptional control of SPRR1B. SPRR1B expression is either detectable or PMA (phorbol 13-myristate 12-acetate) -inducible in several malignant BE cells including squamous, adeno, small and large cell carcinomas. Loss of SPRR1B expression is correlated well with the lack of strong in vivo protein-DNA interactions at the -152 bp promoter, which contains two functional TRE sites. Even though the basal level AP-1 protein DNA binding pattern is different between normal and malignant cells, PMA significantly enhances Jun and Fos binding to the consensus TRE site in both cell types. Intriguingly, the composition of AP-1 protein binding to the -152 to -86 bp SPRR1B promoter is quite different. In untreated cells, SPRR1B promoter is predominantly occupied by JunD and Fra2. PMA significantly induced binding of JunB and Fra1 in normal cells, while JunB and Fra2 bound to TREs in the malignant cells. Overexpression of fra1 in malignant cells significantly enhanced SPRR1B promoter activity. In contrast, overexpression of fra2, but not fra1, strongly reduced both basal and PMA-inducible promoter activities in normal cells. Together, these results indicate that either temporal expression and/or differential activation of AP-1 proteins, especially Fra1 and Fra2, might contribute to the dysregulation of terminal differentiation marker, SPRR1B, expression in various BE cells.

Phorbol ester-induced expression of airway squamous cell differentiation marker, SPRR1B, is regulated by protein kinase Cdelta /Ras/MEKK1/MKK1-dependent/AP-1 signal transduction pathway.

The transcriptional induction of SPRR1B by phorbol 12-myristate 13-acetate (PMA) is mainly mediated by the first -152-base pair 5'-flanking region containing two functional AP-1 sites. In this study, we have analyzed the signaling pathways that mediate the induction in tracheobronchial epithelial cells. PKC inhibitor ablated PMA-stimulated expression of endogenous SPRR1B and reporter gene expression driven by SPRR1B promoter. PKC activator promoted the transcription. The dominant negative protein kinase Cdelta (dn-PKCdelta) and rottlerin (PKCdelta inhibitor) completely suppressed PMA-stimulated promoter activity. dn-Ras or dn-MEKK1 inhibited PMA-stimulated promoter activity, while their corresponding constitutively active mutants augmented it. dn-c-Raf-1 did not have any effect on reporter gene expression. Since MEKK1 activates multiple parallel pathways, we examined involvement of JNK/SAPK, p38, and MKK1 in promoter regulation. Co-expression of the dominant negative forms of MKK4, MKK7, JNK/SAPK, MKK3, MKK6, or p38alpha did not suppress PMA-stimulated reporter gene expression. However, MKK1 inhibitors UO126 and PD98095 suppressed gene expression. Consistent with this, expression of dn-MKK1 strongly suppressed PMA-stimulated promoter activity, while the constitutively active MKK1 augmented it. However, MKK1-mediated induction of SPRR1B probably does not depend on extracellular signal-regulated kinases 1 and 2, suggesting the requirement of another kinase(s). dn-c-Jun mutants abolished PMA-stimulated expression supporting an important role for AP-1 proteins in SPRR1B expression. Together, these results suggest that a PKCdelta/Ras/MEKK1/MKK1-dependent/AP-1 pathway regulates the PMA-inducible expression of the SPRR1B in tracheobronchial epithelial cells.

Infection of a hip prosthesis by Actinomyces naeslundii.

We present the case of a 77-year-old woman who developed an Actinomyces naeslundii infection of a hip prosthesis. The isolate grew well aerobically with 5% CO(2). Possible diagnostic problems may arise in the microbiological laboratory because aerobic growth is not sufficiently accounted for in some of the traditional identification schemes and commercial test kits. Therefore, besides presenting an unusual pathogen in this setting, this report focuses on possible diagnostic problems in the microbiological laboratory.