Periodontitis exacerbation during pregnancy in mice: Role of macrophage migration inhibitory factor as a key inductor.

OBJECTIVE: The present study was designed to investigate the role of macrophage migration inhibitory factor (MIF) in the exacerbation of pregestational periodontal disease (PGPD). BACKGROUND: Periodontitis (PT) is a severe stage of periodontal disease characterized by inflammation of the supporting tissues of the teeth, which usually worsens during pregnancy. MIF is a proinflammatory cytokine that is significantly elevated in periodontitis, both at the beginning and at the end of pregnancy. Although periodontitis usually presents with greater severity during pregnancy, the participation of MIF in the evolution of periodontitis has not been established. METHODS: To analyze the relevance of MIF in the exacerbation of PGPD, we employed a model of PGPD in WT and Mif-/- mice, both with a BALB/c genetic background. PT was induced with nylon suture ligatures placed supramarginally around the second upper right molar. For PGPD, PT was induced 2 weeks before mating. We evaluated histological changes and performed histometric analysis of the clinical attachment loss, relative expression of MMP-2 and MMP-13 by immunofluorescence, and relative expression of the cytokines mif, tnf-α, ifn-γ, and il-17 by quantitative real-time polymerase chain reaction (qRT-PCR). RESULTS: Our data revealed that periodontal tissue from PGPD WT mice produced a twofold increase in MIF compared with PT WT mice. Moreover, the evolution of periodontitis in Mif-/- mice was less severe than in PGDP WT mice. Periodontal tissue from Mif-/- mice with PGPD produced 80% less TNF-α and no IFN-γ, as well as 50% lower expression of matrix metalloproteinase (MMP)-2 and 25% less MMP-13 compared to WT PGDP mice. CONCLUSIONS: Our study suggests that MIF plays an important role in the exacerbation of periodontitis during pregnancy and that MIF is partially responsible for the inflammation associated with the severity of periodontitis during pregnancy.

Extensive Expression of the Virulome Related to Antibiotic Genotyping in Nosocomial Strains of Klebsiella pneumoniae.

The emergence of hyper-virulent and multidrug-resistant (MDR) strains of Klebsiella pneumoniae isolated from patients with hospital- and community-acquired infections is a serious health problem that increases mortality. The molecular analysis of virulome expression related to antimicrobial-resistant genotype and infection type in K. pneumoniae strains isolated from patients with hospital- and community-acquired infections has been poorly studied. In this study, we analyzed the overall expression of the virulence genotype associated with the antimicrobial resistance genotype and pulse field gel electrophoresis (PFGE) type (PFtype) in K. pneumoniae. We studied 25 strains of K. pneumoniae isolated from patients who developed bacteremia and pneumonia during their hospital stay and 125 strains from outpatients who acquired community-acquired infections. Susceptibility to 12 antimicrobials was determined by Kirby-Bauer. The identification of K. pneumoniae and antibiotic-resistance genes was performed using polymerase chain reaction (PCR). To promote the expression of the virulence genes of K. pneumoniae, an in vitro infection model was used in human epithelial cell lines A549 and A431. Bacterial RNA was extracted with the QIAcube robotic workstation, and reverse transcription to cDNA was performed with the Reverse Transcription QuantiTect kit (Qiagen). The determination of the expression of the virulence genes was performed by real-time PCR. In addition, 57.3% (n = 86) of the strains isolated from patients with hospital- and community-acquired infections were multidrug-resistant (MDR), mainly to beta-lactam antibiotics (CB, AM, CFX, and CF), aminoglycosides (GE), quinolones (CPF and NOF), nitrofurantoin (NF), and sulfamethoxazole/trimethoprim (SXT). The most frequently expressed genes among strains isolated from hospital- and community-acquired infections were adhesion-type, ycfm (80%), mrkD (51.3%), and fimH (30.7%); iron uptake, irp2 (84%), fyuA (68.7%), entB (64.7%), and irp1 (56.7%); and protectins, rpmA (26%), which were related to antibiotic-resistance genes, blaTEM (96%), blaSHV (64%), blaCITM (52.6%), blaCTXM-1 (44.7%), tetA (74%), sul1 (57.3%), aac(3)-IV (40.7%), and aadA1 (36%). The results showed the existence of different patterns of expression of virulome related to the genotype of resistance to antimicrobials and to the PFtypes in the strains of K. pneumoniae that cause hospital- and community-acquired infections. These findings are important and may contribute to improving medical treatment strategies against infections caused by K. pneumoniae.

Marked virulence and azole resistance in Candida albicans isolated from patients with periodontal disease.

Candida albicans is an opportunistic fungus frequently associated with periodontal diseases. The objective of this study was to determine the expression patterns of virulence genes associated with those of azole resistance among the strains of C. albicans isolated from patients with periodontal disease. We isolated 80 strains of C. albicans from patients with periodontal disease enrolled from two dental clinics and their antifungal susceptibilities were evaluated using the disc diffusion method. C. albicans and its virulence genes were identified using PCR. The expressions of the virulence genes of C. albicans were analyzed using real-time PCR post in vitro infection of the cell line A549. The phenotype for resistance against azoles such as ketoconazole and fluconazole was observed in all analyzed strains (n = 80), which coincided with the high frequency of occurrence of the genes CDR1 and MDR1 associated with resistance. The frequencies of detection and expression of the genes HWP1 (47/15), ALS1 (80/66), ALS3 (70/30), LIP1 (78/44), LIP4 (77/65), LIP5 (79/58), LIP6 (79/58), PLB1 (79/65), and PLB2 (80/66) were found to be higher in the strains of C. albicans isolated from patients with moderate periodontitis and different expression patterns associated with those for azole resistance were identified. It could be elucidated that the high expression of virulence markers associated with azole resistance in C. albicans might be contributing to the chronicity of periodontal infections.

O-serogroups of multi-drug resistant cervicovaginal Escherichia coli harboring a battery of virulence genes.

Multi-drug resistant cervicovaginal Escherichia coli (CVEC) infections are a serious health problem. The aim of this study is to determine the patterns of virulence genes, antibiotic resistance and O-serogroups of CVEC isolated in Mexico. Two hundred strains of CVEC were isolated from women attending two Clinics at the Instituto Mexicano del Seguro Social. E. coli O-serogroups and virulence markers were identified by PCR. Antibiotic susceptibility was determined using the Kirby-Bauer disc-diffusion method. Serogroups O25 (50%), O75 (9%) and O15 (7.5%) were the most frequent among the CVEC strains isolated. The frequencies for antibiotic resistance were ampicillin 97%, (n = 194); carbenicillin 93.5%, (n = 187); cefalotin 77%, (n = 154); and nitrofurantoin 71%, (n = 142). The frequency of multiresistant isolates (3-12 drugs) was 197 (98.5%). The most frequent virulence genes found were feoB (91.5%), fimH (89.5%), kpsMT11 (75%), iutA (66%), and iroN (59%). One hundred and four distinct patterns of virulence markers with antibiotic-resistance genes associated with O-serogroups were identified amongst CVEC isolates. In conclusion: most CVEC strains isolated were multiresistant to antibiotics, belonged to three O-serogroups, and possessed a battery of virulence factors. This knowledge may lead to improved guidelines and standards for treating cervicovaginal infections.

Snapshot of sequential SNARE assembling states between membranes shows that N-terminal transient assembly initializes fusion.

Many prominent biological processes are driven by protein assembling between membranes. Understanding the mechanisms then entails determining the assembling pathway of the involved proteins. Because the intermediates are by nature transient and located in the intermembrane space, this determination is generally a very difficult, not to say intractable, problem. Here, by designing a setup with sphere/plane geometry, we have been able to freeze one transient state in which the N-terminal domains of SNARE proteins are assembled. A single camera frame is sufficient to obtain the complete probability of this state with the transmembrane distance. We show that it forms when membranes are 20 nm apart and stabilizes by further assembling of the SNAREs at 8 nm. This setup that fixes the intermembrane distance, and thereby the transient states, while optically probing the level of molecular assembly by Förster resonance energy transfer (FRET) can be used to characterize any other transient transmembrane complexes.

Binding of sperm protein Izumo1 and its egg receptor Juno drives Cd9 accumulation in the intercellular contact area prior to fusion during mammalian fertilization.

Little is known about the molecular mechanisms that induce gamete fusion during mammalian fertilization. After initial contact, adhesion between gametes only leads to fusion in the presence of three membrane proteins that are necessary, but insufficient, for fusion: Izumo1 on sperm, its receptor Juno on egg and Cd9 on egg. What happens during this adhesion phase is a crucial issue. Here, we demonstrate that the intercellular adhesion that Izumo1 creates with Juno is conserved in mouse and human eggs. We show that, along with Izumo1, egg Cd9 concomitantly accumulates in the adhesion area. Without egg Cd9, the recruitment kinetics of Izumo1 are accelerated. Our results suggest that this process is conserved across species, as the adhesion partners, Izumo1 and its receptor, are interchangeable between mouse and human. Our findings suggest that Cd9 is a partner of Juno, and these discoveries allow us to propose a new model of the molecular mechanisms leading to gamete fusion, in which the adhesion-induced membrane organization assembles all key players of the fusion machinery.

Comprehensive expression analysis of pathogenicity genes in uropathogenic Escherichia coli strains.

In this study, we investigated distinct expression patterns of genes encoding iron-acquisition systems, adhesins, protectins, and toxins in human uroepithelial cells infected with 194 uropathogenic Escherichia coli (UPEC) strains in vitro. We assessed the association of these genes with antibiotic resistance genes in this group of UPEC strains, previously characterised by polymerase chain reaction (PCR). Strains were isolated from patients with urinary tract infections (UTIs) from Unidad Médica Familiar de Salud Pública, located in Estado de México, México. Antibiotic resistance genes were identified by PCR, and the expression of virulence genes was detected by reverse-transcriptase-PCR after in vitro infection of cultured A431 human keratinocytes derived from a vulvar epidermoid carcinoma. The most frequently expressed virulence genotypes among the investigated UPEC strains included usp (68%), iha (64.9%), kpsMT (61.3%), fim (58.2%), irp2 (48.4), papC (33.5%), set (31.4%) and astA (30.9%), whereas the most frequently detected antibiotic resistance genes were tet(A) (34%), sul1 (31.4%) and TEM (26.3%). Furthermore, the most abundant pattern of gene expression (irp2/fim/iha/kpsMT/usp), associated with 8 different combinations of antibiotic resistance genotypes, was exhibited by 28 strains (14.4%). Taken together, these results indicate collective participation of distinct virulence UPEC genotypes during in vitro infection of cultured human epithelial cells, suggesting their potential involvement in UTI pathogenesis.

High Virulence and Antifungal Resistance in Clinical Strains of Candida albicans.

Antifungal resistance and virulence properties of Candida albicans are a growing health problem worldwide. To study the expression of virulence and azole resistance genes in 39 clinical strains of C. albicans, we used a model of infection of human vaginal epithelial cells with C. albicans strains isolated from Mexican women with vulvovaginal candidiasis (VVC). The strains were identified by PCR amplification of the ITS1 and ITS2 regions of rRNA. The detection and expression of virulence genes and azole resistance genes MDR1 and CDR1 were performed using PCR and RT-PCR, respectively. All strains were sensitive to nystatin and 38 (97.4%) and 37 (94.9%) were resistant to ketoconazole and fluconazole, respectively. ALS1, SAP4-SAP6, LIP1, LIP2, LIP4, LIP6, LIP7, LIP9, LIP10, and PLB1-PLB2 were present in all strains; SAP1 was identified in 37 (94.8%) isolates, HWP1 in 35 (89.7%), ALS3 in 14 (35.8%), and CDR1 in 26 (66.6%). In nearly all of the strains, ALS1, HWP1, SAP4-SAP6, LIP1-LIP10, PLB1, and PLB2 were expressed, whereas CDR1 was expressed in 20 (51.3%) and ALS3 in 14 (35.8%). In our in vitro model of infection with C. albicans, the clinical strains showed different expression profiles of virulence genes in association with the azole resistance gene CDR1. The results indicate that the strains that infect Mexican patients suffering from VVC are highly virulent and virtually all are insensitive to azoles.

Expression of enterotoxin-coding genes in methicillin-resistant Staphylococcus aureus strains isolated from Mexican haemodialysis patients.

BACKGROUND: Methicillin-resistant Staphylococcus aureus (MRSA) causes severe catheter-related infections in haemodialysis patients ranging from local-site infections and septic thrombophlebitis to bacteraemia but the associated virulence factors and exotoxins remain unclear. FINDINGS: We employed an in vitro infection model using reconstituted human epithelium (RHE) to analyse the expression profiles of 4 virulence genes and 12 exotoxin-coding virulence genes in 21 MRSA strains isolated from catheter-related infections in 21 Mexican patients undergoing haemodialysis. All 21 strains (100%) expressed the seg, seh, sei, eta, etb, or hla genes coding staphylococcal toxins. Eleven MRSA strains (52.3%) expressed the sea gene coding staphylococcal enterotoxin A, and two strains (9.5%) expressed the v8 gene coding serine protease. The tst, chp, and arcA genes coding toxic shock syndrome toxin 1, chemotaxis inhibitory protein, and arginine deiminase, respectively, were expressed in separate single strains (4.7%). The most frequent expression profile (42.8% of the strains) comprised seg, seh, sei, eta, etb, and hla. CONCLUSION: It is likely that the SEG, SEH, SEI, ETA, ETB, and Hla toxins may play a role in MRSA catheter-related infections. Consideration of these toxins in the development of a vaccine or as targets for monoclonal antibody therapy could provide an improved therapeutic strategy for the treatment of catheter-related infections in haemodialysis patients.

Implementation of a novel in vitro model of infection of reconstituted human epithelium for expression of virulence genes in methicillin-resistant Staphylococcus aureus strains isolated from catheter-related infections in Mexico.

BACKGROUND: Methicillin-resistant Staphylococcus aureus (MRSA) are clinically relevant pathogens that cause severe catheter-related nosocomial infections driven by several virulence factors. METHODS: We implemented a novel model of infection in vitro of reconstituted human epithelium (RHE) to analyze the expression patterns of virulence genes in 21 MRSA strains isolated from catheter-related infections in Mexican patients undergoing haemodialysis. We also determined the phenotypic and genotypic co-occurrence of antibiotic- and disinfectant-resistance traits in the S. aureus strains, which were also analysed by pulsed-field-gel electrophoresis (PFGE). RESULTS: In this study, MRSA strains isolated from haemodialysis catheter-related infections expressed virulence markers that mediate adhesion to, and invasion of, RHE. The most frequent pattern of expression (present in 47.6% of the strains) was as follows: fnbA, fnbB, spa, clfA, clfB, cna, bbp, ebps, eap, sdrC, sdrD, sdrE, efb, icaA, and agr. Seventy-one percent of the strains harboured the antibiotic- and disinfectant-resistance genes ermA, ermB, tet(M), tet(K), blaZ, qacA, qacB, and qacC. PFGE of the isolated MRSA revealed three identical strains and two pairs of identical strains. The strains with identical PFGE patterns showed the same phenotypes and genotypes, including the same spa type (t895), suggesting hospital personnel manipulating the haemodialysis equipment could be the source of catheter contamination. CONCLUSION: These findings help define the prevalence of MRSA virulence factors in catheter-related infections. Some of the products of the expressed genes that we detected in this work may serve as potential antigens for inclusion in a vaccine for the prevention of MRSA-catheter-related infections.

CD9 tetraspanin generates fusion competent sites on the egg membrane for mammalian fertilization.

CD9 tetraspanin is the only egg membrane protein known to be essential for fertilization. To investigate its role, we have measured, on a unique acrosome reacted sperm brought in contact with an egg, the adhesion probability and strength with a sensitivity of a single molecule attachment. Probing the binding events at different locations of wild-type egg we described different modes of interaction. Here, we show that more gamete adhesion events occur on Cd9 null eggs but that the strongest interaction mode disappears. We propose that sperm-egg fusion is a direct consequence of CD9 controlled sperm-egg adhesion properties. CD9 generates adhesion sites responsible for the strongest of the observed gamete interaction. These strong adhesion sites impose, during the whole interaction lifetime, a tight proximity of the gamete membranes, which is a requirement for fusion to take place. The CD9-induced adhesion sites would be the actual location where fusion occurs.

Energetics and dynamics of SNAREpin folding across lipid bilayers.

Membrane fusion occurs when SNAREpins fold up between lipid bilayers. How much energy is generated during SNAREpin folding and how this energy is coupled to the fusion of apposing membranes is unknown. We have used a surface forces apparatus to determine the energetics and dynamics of SNAREpin formation and characterize the different intermediate structures sampled by cognate SNAREs in the course of their assembly. The interaction energy-versus-distance profiles of assembling SNAREpins reveal that SNARE motifs begin to interact when the membranes are 8 nm apart. Even after very close approach of the bilayers (approximately 2-4 nm), the SNAREpins remain partly unstructured in their membrane-proximal region. The energy stabilizing a single SNAREpin in this configuration (35 k(B)T) corresponds closely with the energy needed to fuse outer but not inner leaflets (hemifusion) of pure lipid bilayers (40-50 k(B)T).

Frequency and expression of ALS and HWP1 genotypes in Candida albicans strains isolated from Mexican patients suffering from vaginal candidosis.

To detect the frequency and expression of eight ALS (agglutinin-like sequence) genes and the HWP1 genotype in a group of Candida albicans strains isolated from Mexican women suffering from vaginal candidosis. A group of 264 women (age 15-57 years) with vaginal infections were evaluated. C. albicans was identified by PCR amplification of the rRNA internal transcribed spacer regions ITS1 and ITS2. The ALS and HWP1 genes were identified by conventional PCR, and their expression levels were determined by real-time PCR after growing C. albicans strains in reconstituted human vaginal epithelium (RHVE). C. albicans was identified in 50 women (18.9%). The genotypic frequencies were ALS1 100%, ALS2 60%, ALS3 36%, ALS4 54%, ALS5 70%, ALS6 56%, ALS7 64%, ALS9 66% and HWP1 92%. The most frequently expressed genes in the strains harbouring all of the genes were ALS4 (100%), ALS1 (87.5%), ALS2 (87.5%), ALS3 (87.5%), ALS5 (87.5%), ALS7 (87.5%) and HWP1 (75.0%). Nineteen per cent of the vaginal infections were caused by C. albicans, and a high proportion of the strains carried genes encoding proteins involved in adhesion to epithelia. The ALS and HWP1 genes were expressed in RHVE, suggesting that the Als and Hwp1 proteins play an important role in the pathogenesis of the infection.

Hypervirulence and Multiresistance to Antibiotics in Klebsiella pneumoniae Strains Isolated from Patients with Hospital- and Community-Acquired Infections in a Mexican Medical Center.

Klebsiella pneumoniae is a pathogenic bacterium associated with different infectious diseases. This study aimed to establish the different association profiles of virulence genes related to the hypermucoviscous phenotype (HM), capsular serotypes, biofilm formation, and multidrug resistance in K. pneumoniae strains from patients with hospital- and community-acquired infections. K. pneumoniae virulence genes and capsular serotypes were identified by PCR, antibiotic susceptibility by the Kirby-Bauer method, HM by the string test, and biofilm formation by measurement in polystyrene microtiter plates. Of a total of 150 strains from patients with hospital- (n = 25) and community-acquired infections (n = 125), 53.3% (80/150) were HM-positive and 46.7% (70/150) were HM-negative. HM-positive (68/80) and HM-negative (67/70) strains were biofilm-forming. Moreover, 58.7% (47/80) HM-positive and 57.1% (40/70) HM-negative strains were multidrug-resistant. Among HM-positive, HM-negative, and serotypes K1 (25/150), K2 (48/150), and non-K1/K2 strains, (77/150) the frequently detected adhesion genes were fimH, mrkD, ycfM, and kpn; entB, irp2, irp1, and ybtS, for iron acquisition; and rmpA for protectins. The gene association pattern fimH/kpn/mrkD/ycfM/entB/irp1/irp2/ybtS/fyuA (18/150) was frequent among the strains. K. pneumoniae strains from patients with hospital- and community-acquired infections demonstrated a wide diversity of virulence gene profiles related to phenotype (hypermucoviscosity, multidrug resistance, and biofilm formation) and serotypes.

High Virulence and Multidrug Resistance of Escherichia coli Isolated in Periodontal Disease.

Periodontal disease is caused by different gram-negative anaerobic bacteria; however, Escherichia coli has also been isolated from periodontitis and its role in periodontitis is less known. This study aimed to determine the variability in virulence genotype, antibiotic resistance phenotype, biofilm formation, phylogroups, and serotypes in different emerging periodontal strains of Escherichia coli, isolated from patients with periodontal disease and healthy controls. E. coli, virulence genes, and phylogroups, were identified by PCR, antibiotic susceptibility by the Kirby-Bauer method, biofilm formation was quantified using polystyrene microtiter plates, and serotypes were determined by serotyping. Although E. coli was not detected in the controls (n = 70), it was isolated in 14.7% (100/678) of the patients. Most of the strains (n = 81/100) were multidrug-resistance. The most frequent adhesion genes among the strains were fimH and iha, toxin genes were usp and hlyA, iron-acquisition genes were fyuA and irp2, and protectin genes were ompT, and KpsMT. Phylogroup B2 and serotype O25:H4 were the most predominant among the strains. These findings suggest that E. coli may be involved in periodontal disease due to its high virulence, multidrug-resistance, and a wide distribution of phylogroups and serotypes.

Medical student procedures and attending faculty exposure.

BACKGROUND: The aim of this study was to determine whether medical students working with the same attending on multiple shifts as opposed to a variety of attendings leads to the performance of more procedures during their emergency medicine (EM) elective. METHODS: This was a retrospective observational study conducted in an Emergency Department with a census of 150,000 patients per year and a 3 year EM residency. Fourth-year medical student Attendance/Procedure Logs from July 2004 to March 2007 were reviewed. Students were divided into two groups: those who worked four or more shifts with a single attending (study group) and those who worked less than four shifts with any single attending (control group). The number of procedures performed in each group was compared. RESULTS: Of 144 medical students, 63 (43.8%) were in the study group and 81 (56.2%) were in the control group. During the study dates, medical students recorded a total of 1327 procedures. Mean number of procedures performed in the study group (12.9, 95% CI 11.7 to 14.0) was higher than in the control group (6.3, 95% CI 5.4 to 7.2). This pattern remained true in every recorded category: arterial blood gas, abscess drainage, laceration repair, lumbar puncture and nasogastric tube. CONCLUSION: Medical students that worked four or more shifts with a single EM attending performed twice as many overall procedures (12.9 vs 6.3) and significantly more invasive procedures than medical students who worked with a variety of attendings during their 4th-year EM elective.

Frequency and expression of genes involved in adhesion and biofilm formation in Staphylococcus aureus strains isolated from periodontal lesions.

BACKGROUND/PURPOSE: The aim of this study was to characterize the Staphylococcus aureus strains isolated from periodontal lesions of patients, to determine the expression of genes involved in cell adhesion upon their infection of human epithelial cells using an in vitro model, its biofilm formation, and its resistance to antibiotics. METHODS: S. aureus was analysed by PCR, Kirby-Bauer, and pulsed-field gel electrophoresis (PFGE), measuring gene expression by real-time PCR after infection of human cells in vitro. RESULTS: S. aureus was identified in 18.6% (50/268) of the samples. All strains (n = 50) possessed the virulence genes spa (Staphylococcal protein A), coa (coagulase), and icaAB (intercellular adhesin); 96% (n = 48) possessed clfB (clumping factor B), and 88% (n = 44) possessed ebps (elastin-binding protein) and sdrD (serine aspartate repeat protein D). All strains were resistant to methicillin, ampicillin, dicloxacillin, cefotaxime, and penicillin, and were multidrug resistant to 6-12 antibiotics. PFGE analysis showed 37 different pulsed-field types and most strains (60.4%) had a unique pulsed-field type. Twenty-four distinct combinations of virulence genes and antibiotic-resistant phenotypes were identified. CONCLUSION: Although S. aureus has been considered a transient member of the oral microbiota, our results indicate a high-level expression of virulence genes and multidrug resistance in the strains isolated from periodontal lesions. These strains might complicate the successful treatment of the disease.

Using 6 Degrees of Freedom to Systematically Reduce and Fix Distal Radius Fractures.

Six degrees of freedom (6DOF) refers to the freedom of movement of a rigid body in 3-dimensional space. Specifically, the object can move in 3 translations: up/down, left/right, and in/out, and in 3 rotations: pitch, yaw, and roll. In fracture care, the principle of 6DOF can be applied to each individual fracture fragment to help better understand fracture reduction and alignment. In the instance of a distal radius fracture, the 6DOF concept can be utilized to reduce the articular block in a systematic and controlled fashion. The articular block may be displaced in 3 translations-shortened (proximal/distal axis), dorsally translated (volar/dorsal axis), and radially translated (radial/ulnar axis). The articular block may also be displaced in 3 rotations-dorsally tilted (rotated about the radial/ulnar axis or in the sagittal plane), decreased radial inclination (rotated about the volar/dorsal axis or in the coronal plane), and supinated (rotated about the proximal/distal axis or in the axial plane). We present a surgical technique of open reduction and internal fixation of a distal radius fracture through a volar approach where we address the distal segment's instability in 6DOF in a stepwise format.

Synaptotagmin-1 membrane binding is driven by the C2B domain and assisted cooperatively by the C2A domain.

Synaptotagmin interaction with anionic lipid (phosphatidylserine/phosphatidylinositol) containing membranes, both in the absence and presence of calcium ions (Ca2+), is critical to its central role in orchestrating neurotransmitter release. The molecular surfaces involved, namely the conserved polylysine motif in the C2B domain and Ca2+-binding aliphatic loops on both C2A and C2B domains, are known. Here we use surface force apparatus combined with systematic mutational analysis of the functional surfaces to directly measure Syt1-membrane interaction and fully map the site-binding energetics of Syt1 both in the absence and presence of Ca2+. By correlating energetics data with the molecular rearrangements measured during confinement, we find that both C2 domains cooperate in membrane binding, with the C2B domain functioning as the main energetic driver, and the C2A domain acting as a facilitator.

Temporal and region-specific effects of sleep fragmentation on gut microbiota and intestinal morphology in Sprague Dawley rats.

Sleep is a fundamental biological process, that when repeatedly disrupted, can result in severe health consequences. Recent studies suggest that both sleep fragmentation (SF) and dysbiosis of the gut microbiome can lead to metabolic disorders, though the underlying mechanisms are largely unclear. To better understand the consequences of SF, we investigated the effects of acute (6 days) and chronic (6 weeks) SF on rats by examining taxonomic profiles of microbiota in the distal ileum, cecum and proximal colon, as well as assessing structural and functional integrity of the gastrointestinal barrier. We further assayed the impact of SF on a host function by evaluating inflammation and immune response. Both acute and chronic SF induced microbial dysbiosis, more dramatically in the distal ileum (compared to other two regions studied), as noted by significant perturbations in alpha- and beta-diversity; though, specific microbial populations were significantly altered throughout each of the three regions. Furthermore, chronic SF resulted in increased crypt depth in the distal ileum and an increase in the number of villi lining both the cecum and proximal colon. Additional changes were noted with chronic SF, including: decreased microbial adhesion and penetration in the distal ileum and cecum, elevation in serum levels of the cytokine KC/GRO, and depressed levels of corticotropin. Importantly, our data show that perturbations to microbial ecology and intestinal morphology intensify in response to prolonged SF and these changes are habitat specific. Together, these results reveal consequences to gut microbiota homeostasis and host response following acute and chronic SF in rats.