Localized diacylglycerol-dependent stimulation of Ras and Rap1 during phagocytosis.

We describe a role for diacylglycerol in the activation of Ras and Rap1 at the phagosomal membrane. During phagocytosis, Ras density was similar on the surface and invaginating areas of the membrane, but activation was detectable only in the latter and in sealed phagosomes. Ras activation was associated with the recruitment of RasGRP3, a diacylglycerol-dependent Ras/Rap1 exchange factor. Recruitment to phagosomes of RasGRP3, which contains a C1 domain, parallels and appears to be due to the formation of diacylglycerol. Accordingly, Ras and Rap1 activation was precluded by antagonists of phospholipase C and of diacylglycerol binding. Ras is dispensable for phagocytosis but controls activation of extracellular signal-regulated kinase, which is partially impeded by diacylglycerol inhibitors. By contrast, cross-activation of complement receptors by stimulation of Fcgamma receptors requires Rap1 and involves diacylglycerol. We suggest a role for diacylglycerol-dependent exchange factors in the activation of Ras and Rap1, which govern distinct processes induced by Fcgamma receptor-mediated phagocytosis to enhance the innate immune response.

Enterococcus faecalis PcfC, a spatially localized substrate receptor for type IV secretion of the pCF10 transfer intermediate.

Upon sensing of peptide pheromone, Enterococcus faecalis efficiently transfers plasmid pCF10 through a type IV secretion (T4S) system to recipient cells. The PcfF accessory factor and PcfG relaxase initiate transfer by catalyzing strand-specific nicking at the pCF10 origin of transfer sequence (oriT). Here, we present evidence that PcfF and PcfG spatially coordinate docking of the pCF10 transfer intermediate with PcfC, a membrane-bound putative ATPase related to the coupling proteins of gram-negative T4S machines. PcfC and PcfG fractionated with the membrane and PcfF with the cytoplasm, yet all three proteins formed several punctate foci at the peripheries of pheromone-induced cells as monitored by immunofluorescence microscopy. A PcfC Walker A nucleoside triphosphate (NTP) binding site mutant (K156T) fractionated with the E. faecalis membrane and also formed foci, whereas PcfC deleted of its N-terminal putative transmembrane domain (PcfCDelta N103) distributed uniformly throughout the cytoplasm. Native PcfC and mutant proteins PcfCK156T and PcfCDelta N103 bound pCF10 but not pcfG or Delta oriT mutant plasmids as shown by transfer DNA immunoprecipitation, indicating that PcfC binds only the processed form of pCF10 in vivo. Finally, purified PcfCDelta N103 bound DNA substrates and interacted with purified PcfF and PcfG in vitro. Our findings support a model in which (i) PcfF recruits PcfG to oriT to catalyze T-strand nicking, (ii) PcfF and PcfG spatially position the relaxosome at the cell membrane to stimulate substrate docking with PcfC, and (iii) PcfC initiates substrate transfer through the pCF10 T4S channel by an NTP-dependent mechanism.

Changes in 911 call volume and type during Hurricane Ike and the implementation and usefulness of the TeleHealth Nurse system for the Houston Fire Department

This study examined both changing call volume and type with resulting effect of TeleHealth Nurse, the Houston Fire Department's (HFD) telephone nurse line, on call burden during Hurricane Ike. On September 13, 2008, Hurricane Ike made landfall in the Galveston area and continued north through Houston resulting in catastrophic damages in infrastructure and posing a public health threat. The overall goal of this study looked at data from Houston Fire Department to obtain a better understanding of the needs of citizens before, during, and after a hurricane. This study looked at four aspects of emergency response from HFD. The first section looked at call volumes surrounding the time of Hurricane Ike in 2008 compared to the same time period in 2007. The data showed a 12% increase in calls surrounding Hurricane Ike compared to previous years with a p value <.001. Next, the study evaluated the types of calls prevalent during Hurricane Ike compared to the same time period in 2007. The data showed a statistically significant increase in chronic health problems such as diabetes and cardiac events, Obstetric calls and an increase in breathing problems, falls, and lacerations during the days following Hurricane Ike. There was also a statistically significant increase in auto med alerts and check patients surrounding Hurricane Ike's landfall. The third section analyzed the change in call volume sent to HFD's Telephone Nurse Line during Hurricane Ike and compares this to earlier time periods while the fourth and final section looks at the types of calls sent to the nurse line during Hurricane Ike. The data showed limited use of the TeleHealth Nurse line before Hurricane Ike, but when the winds were at their strongest and ambulances were unable to leave the station, the nurse line was the only functioning medical help some people were able to receive. These studies bring a better understanding to the number and types of calls that a city might experience during a natural disaster, such as a hurricane. This study also shows the usefulness of an EMS Telephone Nurse Line during a natural disaster.^

Teaching safety at a summer camp: Evaluation of a children's fire safety curriculum in an urban community setting

Objectives: The purpose of this study was to evaluate the effectiveness of the Danger Rangers Fire Safety Curriculum in increasing the fire safety knowledge of low-income, minority children in pre-kindergarten to third grade in Austin, TX during a summer day camp in 2007.^ Methods: Data was collected from child participants via teacher and researcher administered tests at pretest, posttest (immediately after the completion of the fire safety module), and at a 3 week follow-up to asses retention. In addition, a self-administered questionnaire was collected from parents pre- and post-intervention to assess home-related fire/burn risk factors. Paired t-tests were conducted using STATA 12.0 to evaluate pretest, posttest, and retention test mean scores as well as mean fire safety rules listed by grade group. McNemar's test was used to determine if there was a difference in fire-related risk factors as reported by the parents of the participants before and after the intervention. Only those who had paired data for the tests/surveys being compared were included in the analysis.^ Results: The first/second grade group and the third grade group scored significantly higher on fire safety knowledge on the posttest compared to the pretest (p<0.0001 for both groups). However, there was no significant change in knowledge scores for the pre-kindergarten to kindergarten group (p=0.14). Among the first/second grade group, knowledge levels did not significantly decline between the posttest and retention test (p=0.25). However, the third grade group had significantly lower fire safety knowledge scores on the retention test compared to the posttest (p<0.001). A similar increase was seen in the amount of fire safety rules listed after the intervention (p<0.0001 between pre and posttest for both the first/second grade and third grade groups), with no decline from the posttest to the retention test (p=0.50) for the first/second grade group, but a significant decline in the third grade group (p=0.001). McNemar's chi-square test showed a significant increase in the percentage of participants' parents reporting smoke detector testing on a regular basis and having a fire escape plan for their family after the intervention (p=0.01 and p<0.0001, respectively). However, there was no significant change in the frequency of reports of the child playing in the kitchen while the parent cooks or the house/apartment having a working smoke detector.^ Conclusion: We found that general fire safety knowledge improved and the number of specific fire safety rules increased among the first to third grade children who participated in the Danger Rangers fire safety program. However, it did not significantly increase general fire safety knowledge among the pre-k/k group. This study also showed that a program targeted towards children has the potential to influence familial risk factors by proxy. The Danger Rangers Fire Safety Curriculum should be further evaluated by conducting a randomized controlled trial, using valid measures that assess fire safety attitudes, beliefs, behaviors, as well as fire/burn related outcomes.^

Use of universal precautions in the workplace: A comparison of two fire /EMS services

The Health Belief Model (HBM) provided the theoretical framework for examining Universal Precautions (UP) compliance factors by Firefighter, EMTs and Paramedics (prehospital care providers). A convenient sample of prehospital care providers (n = 4000) from two cities (Houston and Washington DC), were surveyed to explore the factors related to their decision to comply with Universal Precautions. Eight hundred and sixty-five useable questionnaires were analyzed. The responders were primarily male (95.7%) eight hundred and twenty-eight and thirty-seven were female, prehospital based (100%), EMTs (60.0%) and paramedics (12.8%) who had a mean 13 years of prehospital care experience. ^ Linear regression was used to evaluate the four hypotheses. The first hypothesis evaluating perceived susceptibility and seriousness with reported UP use was statistically significant (p = < .05). Perceived susceptibility, when considered independently, did not make a significant contribution (t = −4.2852; p = 0.0000) to the stated use of Universal precautions. The hypothesis is not supported as stated. The data indicates the opposite effect. Supported is the premise that as perceived susceptibility and perceived seriousness increase the use of Universal Precautions decreases. Hypothesis two tested perceived benefits with internal and external barriers. Both perceived benefits and internal and external barriers as well as the overall regression were significant (F = 112.6, p = 0.0000). The contribution of internal and external barriers was statistically significant (t = 0.0175; p = 0.0000) and (t = 0.0128; p = 0.0000). Hypothesis three which tested modifying factors, cues to action, select demographic variables, and the main effects of the HBM with self reported UP compliance overall was significant. The variables gender, birth, education, job type, EMS certification, years of service, years of experience providing patient care, Universal Precautions training hours, type of apparatus assigned to and the number of EMS related incidents responded to in a month were found to have a significant contribution to the stated use of Universal Precautions. ^ The additive effects were tested by use of a stepwise regression that assessed the contribution of each of the significant variables. Three variables in the equation were statistically significant. Internal barriers (t = −8.5507; p = 0.0000), external barriers (t = −6.2862; p = 0.000) and job type 2 & 3. Job type two (t = −2.8464; p = 0.0045 is titled Engineer/Operator. Job type three (t = −2.5730; p = 0.0103) is titled captain. The overall regression was significant (F = 24.06; p = 0.000). The Hypothesis is supported in the certain demographic variables do influence the stated use of Universal precautions and that as internal and external barriers are decreased, there is an increase in the stated use of Universal Precautions. ^ In summary, this study demonstrated that internal and external barriers have a significant impact on the stated use of Universal Precautions. Internal barriers are those factors within the individual that require an internal change (i.e., forgetfulness, freedom, perception of the urgency of the patient's needs etc.) and external barriers are things in the environment that can be altered (i.e., equipment design, availability of equipment, ease of use). These two model variables explained 23%–30% of the variance. ^

Identification and characterization of the vegetally localized Hermes mRNA

One way developing embryos regulate the expression of their genes is by localizing mRNAs to specific subcellular regions. In the oocyte of the frog, Xenopus laevis, many RNAs are localized specifically to the animal or the vegetal halves of the oocyte. The localization of these RNAs contributes to the primary polarity of the oocyte, the asymmetry that is the basis for patterning and lineage specification in the embryo. I have screened a cDNA library for clones containing the Xlsirt repeat, an element known to target RNAs to the vegetal cortex of the oocyte. I have identified seventeen cDNA clones that contain this element. One of these cDNAs encodes the RNA binding protein Hermes. The Hermes mRNA is localized to the vegetal cortex of the oocyte. Additionally, Hermes protein is also vegetally localized in the oocyte and is found in subcellular structures known to contain localized mRNAs. This suggests that Hermes might interact with localized RNAs. While Hermes protein is present in oocytes, it disappears at germinal vesicle breakdown during maturation. We therefore believe that the time period during which Hermes functions is during oogenesis or maturation prior to the time of Hermes degradation. To determine Hermes function, an antisense depletion strategy was used that involved injecting morpholino oligos (HE-MO) into oocytes. Injection of these morpholinos causes the level of Hennes protein to drop prematurely during maturation. Embryos produced from these oocytes exhibit cleavage defects that are most prevalent in the vegetal blastomeres. The phenotype can be partially rescued by injection of a heterologous Hermes mRNA and is therefore specific to Hermes. The Hermes expression and depletion results are consistent with a model in which Hermes interacts with one or more vegetally localized mRNAs in the oocyte and during the early stages of maturation. The interaction is required for cleavage of the vegetal blastomeres. Therefore, it is likely that at least one mRNA that interacts with Hermes is a cell cycle regulator. ^