bluuebunny/crossref_metadata_2025_split huggingface dataset:
Preinspiratory calcium rise in putative pre‐Bötzinger complex astrocytes
Authors: Okada Yasumasa , Sasaki Takuya , Oku Yoshitaka , Takahashi Naoya , Seki Megumi , Ujita Sakiko , Tanaka Kenji F. , Matsuki Norio , Ikegaya Yuji 
Published: July 2012

Key points
Autonomic respiratory rhythm is essential to maintain lives and is generated in the lower brainstem. The ventrolateral medullary region, called the pre‐Bötzinger complex (preBötC), is the kernel for respiratory rhythm generation. Despite previous extensive studies focusing on neurons, the mechanism of how respiratory rhythm is generated has not been fully understood.
Here we show that non‐neuronal glial cells (a subset of putative astrocytes) in the preBötC are periodically activated preceding inspiratory neuronal activity, periodic activity of putative astrocytes persists during blockade of neuronal activity, and stimulation of astrocytes in the preBötC induces inspiratory neuronal firings.
These findings together with the previous report that blockade of astrocytic metabolism abolishes inspiratory neural output suggest that astrocytes are functionally involved in respiratory rhythm generation.
These results will help us better understand how respiratory rhythm is generated and how respiratory output is disturbed in various pathological conditions.
Abstract  The neural inspiratory activity originates from a ventrolateral medullary region called the pre‐Bötzinger complex (preBötC), yet the mechanism underlying respiratory rhythmogenesis is not completely understood. Recently, the role of not only neurons but astrocytes in the central respiratory control has attracted considerable attention. Here we report our discovery that an intracellular calcium rise in a subset of putative astrocytes precedes inspiratory neuronal firing in rhythmically active slices. Functional calcium imaging from hundreds of preBötC cells revealed that a subset of putative astrocytes exhibited rhythmic calcium elevations preceding inspiratory neuronal activity with a time lag of approximately 2 s. These preinspiratory putative astrocytes maintained their rhythmic activities even during the blockade of neuronal activity with tetrodotoxin, whereas the rhythm frequency was lowered and the intercellular phases of these rhythms were decoupled. In addition, optogenetic stimulation of preBötC putative astrocytes induced firing of inspiratory neurons. These findings raise the possibility that astrocytes in the preBötC are actively involved in respiratory rhythm generation in rhythmically active slices.
Regulation of hippocampus‐dependent memory by the zinc finger protein Zbtb20 in mature CA1 neurons
Authors: Ren Anjing , Zhang Huan , Xie Zhifang , Ma Xianhua , Ji Wenli , He David Z.Z. , Yuan Wenjun , Ding Yu‐Qiang , Zhang Xiao‐Hui , Zhang Weiping J. 
Published: July 2012

Key points
Zinc finger and BTB domain‐containing protein 20 (Zbtb20) plays a critical role in hippocampal development.
In the present study, we generated mutant mice in which Zbtb20 knockout was restricted to mature CA1 pyramidal cells of the hippocampus.
Conditionally deleting Zbtb20 specifically in mature CA1 pyramidal neurons impaired LTP and memory.
We found that Zbtb20 controls memory formation and synaptic plasticity by regulating NMDAR activity, and activation of ERK and CREB.
Abstract  The mammalian hippocampus harbours neural circuitry that is crucial for associative learning and memory. The mechanisms that underlie the development and regulation of this complex circuitry are not fully understood. Our previous study established an essential role for the zinc finger protein Zbtb20 in the specification of CA1 field identity in the developing hippocampus. Here, we show that conditionally deleting Zbtb20 specifically in mature CA1 pyramidal neurons impaired hippocampus‐dependent memory formation, without affecting hippocampal architecture or the survival, identity and basal excitatory synaptic activity of CA1 pyramidal neurons. We demonstrate that mature CA1‐specific Zbtb20 knockout mice exhibited reductions in long‐term potentiation (LTP) and NMDA receptor (NMDAR)‐mediated excitatory post‐synaptic currents. Furthermore, we show that activity‐induced phosphorylation of ERK and CREB is impaired in the hippocampal CA1 of Zbtb20 mutant mice. Collectively, these results indicate that Zbtb20 in mature CA1 plays an important role in LTP and memory by regulating NMDAR activity, and activation of ERK and CREB.
Characterization of a Conjugate between Rose Bengal and Chitosan for Targeted Antibiofilm and Tissue Stabilization Effects as a Potential Treatment of Infected Dentin
Authors: Shrestha Annie , Hamblin Michael R. , Kishen Anil 
Published: July 2012

ABSTRACT

Bacterial biofilms and dentin structural changes are some of the major challenges in the management of infected dentin tissue. This study characterized a photosensitizer-conjugated chitosan with enhanced photodynamic efficacy against dental biofilms, as well as the ability to reinforce the postinfected dentin matrix in order to improve its mechanical and chemical stability. Rose Bengal-conjugated chitosan (CSRB) was synthesized using a chemical cross-linking method and characterized for photophysical, photobiological, and cytotoxicity properties. Its potential as an antibacterial and matrix-reinforcing agent on dentin collagen was also evaluated.
Enterococcus faecalis
as planktonic and
in vitro
biofilms was treated with CSRB and photodynamically activated with 5 to 60 J/cm
2
green light. Dentin collagen was used for the CSRB cross-linking experiments and evaluated for chemical changes, resistance to enzymatic degradation, and mechanical properties. CSRB was a photosensitizer with efficient singlet oxygen yield.
In vitro
photoactivation gave higher fibroblast cell survival than did RB alone. CSRB showed significant antibiofilm photoinactivation (
P
< 0.01). The CSRB-cross-linked dentin collagen showed higher resistance to collagenase degradation and superior mechanical properties (
P
< 0.05). In summary, the photoactivated CSRB particles synthesized in this study may be a synergistic multifunctional treatment approach with lower cytotoxicity and effective antibiofilm activity as well as the ability to reinforce the dentin collagen to enhance resistance to degradation and improve mechanical properties. This may be a targeted treatment strategy to deal with infected dentin hard tissues in a clinical scenario, where both disinfection and structural integrity need to be addressed concomitantly.
FimA, FimF, and FimH Are Necessary for Assembly of Type 1 Fimbriae on Salmonella enterica Serovar Typhimurium
Authors: Zeiner Sarah A. , Dwyer Brett E. , Clegg Steven 
Published: July 2012

ABSTRACT

Salmonella enterica
serovar Typhimurium is a Gram-negative member of the family
Enterobacteriaceae
and is a common cause of bacterial food poisoning in humans. The fimbrial appendages are found on the surface of many enteric bacteria and enable the bacteria to bind to eukaryotic cells.
S
. Typhimurium type 1 fimbriae are characterized by mannose-sensitive hemagglutination and are assembled via the chaperone/usher pathway.
S
. Typhimurium type 1 fimbrial proteins are encoded by the
fim
gene cluster (
fimAICDHFZYW
), with
fimAICDHF
expressed as a single transcriptional unit. The structural components of the fimbriae are FimA (major subunit), FimI, FimH (adhesin), and FimF (adaptor). In order to determine which components are required for fimbrial formation in
S
. Typhimurium, mutations in
fimA
,
fimI
,
fimH
, and
fimF
were constructed and examined for their ability to produce surface-assembled fimbriae.
S
. Typhimurium SL1344Δ
fimA
, -Δ
fimH
, and -Δ
fimF
mutants were unable to assemble fimbriae, indicating that these genes are necessary for fimbrial production in
S
. Typhimurium. However, SL1344Δ
fimI
was able to assemble fimbriae. In
Escherichia coli
type 1 and Pap fimbriae, at least two adaptors are expressed in addition to the adhesins. However,
E. coli
type 1 and Pap fimbriae have been reported to be able to assemble fimbriae in the absence of these proteins. These results suggest differences between the
S
. Typhimurium type 1 fimbrial system and the
E. coli
type 1 and Pap fimbrial systems.
Diarrhea and Colitis in Mice Require the Salmonella Pathogenicity Island 2-Encoded Secretion Function but Not SifA or Spv Effectors
Authors: Fierer Joshua , Okamoto Sharon , Banerjee Ananya , Guiney Donald G. 
Published: July 2012

ABSTRACT

We investigated the roles of
Salmonella
pathogenicity island 2 (SPI-2) and two SPI-2 effectors in
Salmonella
colitis and diarrhea in genetically resistant BALB/c.D2

Slc11a1

congenic mice with the wild-type Nramp1 locus. Wild-type
Salmonella enterica
serovar Typhimurium 14028s caused a pan-colitis, and the infected mice developed frank diarrhea with a doubling of the fecal water content. An
ssaV
mutant caused only a 26% increase in fecal water content, without producing the pathological changes of colitis, and it did not cause weight loss over a 1-week period of observation. However, two SPI-2 effector mutants, the
spvB
and
sifA
mutants, and a double
spvB sifA
mutant caused diarrhea and colitis, even though the
sifA
mutant was sensitive to killing by bone marrow-derived macrophages from BALB/c.D2 mice and was severely impaired in extraintestinal growth but not in growth in the cecum. These results demonstrate that systemic
S. enterica
infection and diarrhea/colitis are distinct pathogenic processes and that only the former requires
spvB
and
sifA
.
The Toxoplasma gondii Peptide AS15 Elicits CD4 T Cells That Can Control Parasite Burden
Authors: Grover Harshita Satija , Blanchard Nicolas , Gonzalez Federico , Chan Shiao , Robey Ellen A. , Shastri Nilabh 
Published: July 2012

ABSTRACTThe apicomplexan parasiteToxoplasma gondiican cause severe disease in immunocompromised individuals. Previous studies in mice have focused largely on CD8+T cells, and the role of CD4 T cells is relatively unexplored. Here, we show that immunization of the C57BL/6 strain of mice, in which the immunodominant CD8 T cell response to the parasite dense-granule protein GRA6 cannot be generated, leads to a prominent CD4 T cell response. To identify the CD4 T cell-stimulating antigens, we generated aT. gondii-specific,lacZ-inducible, CD4 T cell hybridoma and used it as a probe to screen aT. gondiicDNA library. We isolated a cDNA encoding a protein of unknown function that we call CD4Ag28m and identified the minimal peptide, AS15, which was presented by major histocompatibility complex (MHC) class II molecules to the CD4 T cells. Immunization of mice with the AS15 peptide provided significant protection against subsequent parasite challenge, resulting in a lower parasite burden in the brain. Our findings identify the first CD4 T cell-stimulating peptide that can confer protection against toxoplasmosis and provide an important tool for the study of CD4 T cell responses and the design of effective vaccines against the parasite.
HcpR of Porphyromonas gingivalis Is Required for Growth under Nitrosative Stress and Survival within Host Cells
Authors: Lewis Janina P. , Yanamandra Sai S. , Anaya-Bergman Cecilia 
Published: July 2012

ABSTRACT

Although the Gram-negative, anaerobic periodontopathogen
Porphyromonas gingivalis
must withstand nitrosative stress, which is particularly high in the oral cavity, the mechanisms allowing for protection against such stress are not known in this organism. In this study, microarray analysis of
P. gingivalis
transcriptional response to nitrite and nitric oxide showed drastic upregulation of the PG0893 gene coding for hybrid cluster protein (Hcp), which is a putative hydroxylamine reductase. Although regulation of
hcp
has been shown to be OxyR dependent in
Escherichia coli
, here we show that in
P. gingivalis
its expression is dependent on the Fnr-like regulator designated HcpR. Growth of the isogenic mutant V2807, containing an
ermF-ermAM
insertion within the
hcpR
(PG1053) gene, was significantly reduced in the presence of nitrite (
P
< 0.002) and nitric oxide-generating nitrosoglutathione (GSNO) (
P
< 0.001), compared to that of the wild-type W83 strain. Furthermore, the upregulation of PG0893 (
hcp
) was abrogated in V2807 exposed to nitrosative stress. In addition, recombinant HcpR bound DNA containing the
hcp
promoter sequence, and the binding was hemin dependent. Finally, V2807 was not able to survive with host cells, demonstrating that HcpR plays an important role in
P. gingivalis
virulence. This work gives insight into the molecular mechanisms of protection against nitrosative stress in
P. gingivalis
and shows that the regulatory mechanisms differ from those in
E. coli
.
Infection with Mycobacterium avium subsp. paratuberculosis Results in Rapid Interleukin-1β Release and Macrophage Transepithelial Migration
Authors: Lamont Elise A. , O'Grady Scott M. , Davis William C. , Eckstein Torsten , Sreevatsan Srinand 
Published: July 2012

ABSTRACTPathogen processing by the intestinal epithelium involves a dynamic innate immune response initiated by pathogen-epithelial cell cross talk. Interactions between epithelium andMycobacterium aviumsubsp.paratuberculosishave not been intensively studied, and it is currently unknown how the bacterium-epithelial cell cross talk contributes to the course of infection. We hypothesized thatM. aviumsubsp.paratuberculosisharnesses host responses to recruit macrophages to the site of infection to ensure its survival and dissemination. We investigated macrophage recruitment in response toM. aviumsubsp.paratuberculosisusing a MAC-T bovine macrophage coculture system. We show thatM. aviumsubsp.paratuberculosisinfection led to phagosome acidification within bovine epithelial (MAC-T) cells as early as 10 min, which resulted in upregulation of interleukin-1β (IL-1β) at transcript and protein levels. Within 10 min of infection, macrophages were recruited to the apical side of MAC-T cells. Inhibition of phagosome acidification or IL-1β abrogated this response, while MCP-1/CCL-2 blocking had no effect. IL-1β processing was dependent upon Ca2+uptake from the extracellular medium and intracellular Ca2+oscillations, as determined by EGTA and BAPTA-AM [1,2-bis(2-aminophenoxy) ethane-N,N,N′,N′-tetraacetic acid tetrakis (acetoxymethyl ester)] treatments. Thus,M. aviumsubsp.paratuberculosisis an opportunist that takes advantage of extracellular Ca2+-dependent phagosome acidification and IL-1β processing in order to efficiently transverse the epithelium and enter its niche—the macrophage.
Physical activity/fitness peaks during perimenopause and BMI change patterns are not associated with baseline activity/fitness in women: a longitudinal study with a median 7-year follow-up
Authors: Sui Xuemei , Zhang Jiajia , Lee Duck-chul , Church Timothy S , Lu Wenbin , Liu Junxiu , Blair Steven N 
Published: July 2012

ObjectiveTo assess the age-associated longitudinal trends in cardiorespiratory fitness (CRF), leisure-time physical activity (PA), and body mass index (BMI) across the lifespan in a cohort of adult women.MethodsThe sample included 1467 women from the Aerobics Center Longitudinal Study who were 30–79 years old at baseline and had 3–22 health examinations between 1971 and 2006. CRF was quantified by maximal Balke treadmill exercise tests. The total metabolic equivalent-minutes/week of self-reported PA and measured BMI (kg/m2) were calculated.ResultsThe overall pattern of CRF decreased over time. After age 60 years, fitness level tended to decline rapidly. Women at age 50 had the highest PA level, which decreased after age 50 and plateaued at age 60. The overall pattern of BMI increased with age. However, after age 60 years the rate of increase in BMI became much slower. Adjusting for smoking, health status, and the individual exposures of CRF, PA and BMI did not influence the observed associations. Women who did not meet current PA recommendation or those who were low fit at baseline had a higher BMI throughout adulthood than their more active or fit peers, but the trajectory of BMI was unassociated with baseline activity or fitness levels.ConclusionWe concluded that the age-related longitudinal patterns in physical activity and fitness are not linear. Baseline activity and fitness levels are associated with BMI status during adulthood, but do not affect BMI change trajectory.
Heat illness surveillance in schoolboys participating in physical education class in tropical climate: an analytical prospective descriptive study
Authors: Somboonwong Juraiporn , Sanguanrungsirikul Sompol , Pitayanon Chatchatchai 
Published: July 2012

ObjectivesThis study aimed to determine thermoregulatory and cardiovascular responses as well as the occurrence of heat illness in children exercising outdoors in physical education class under hot and humid climate. Little information regarding this issue under real-life situation is available, especially in the Southeast Asia.DesignAnalytical, prospective descriptive study.SettingA primary school in Bangkok, Thailand.ParticipantsA total of 457 schoolboys (aged 5.5–12 years) were observed while exercising outdoors during their physical education classes throughout the academic year of 2009, including semester 1 (between July and September 2009) and semester 2 (between November 2009 and February 2010).Primary and secondary outcome measuresPrimary outcome measure was tympanic temperature. Secondary outcome measures included blood pressure, heart rate, hydration status and the occurrence of heat-related illness.ResultsOutdoor physical activity consisted of skill practice (duration 24.11±11.04 min, intensity <3 metabolic equivalent of tasks) and playing sports (duration 11.48±5.53 min, intensity 2.6–8.8 metabolic equivalent of tasks). After exercise, tympanic temperature increased by 0.66±0.41°C. There were 20 (4.4%) students whose ear temperature exceeded 38°C, 18 of whom did not consume water. The RR of increasing body temperature up to 38°C in overweight students was 2.1-fold higher than normal-weight students. The per cent change in mean arterial pressure and heart rate increased by 20.16±15.34% and 23.94±19.78%, respectively. Sweat and dehydration rates were 391.16±186.75 ml/h and 0.63±0.26%, respectively. No evidence of heat illness was found. Wet bulb globe temperatures of semesters 1 and 2 were 29.95±1.87°C and 28.32±2.39°C, respectively.ConclusionsThere is an increased risk for heat illness during outdoor activities in physical education class in primary school children, especially those who are overweight and have poor hydration status.
A case–control study on risk factors associated with death in pregnant women with severe pandemic H1N1 infection
Authors: Li Furong , Chen Guoping , Wang Jianjun , Liu Hong , Wu Jiabing 
Published: July 2012

ObjectivesTo describe the risk factors associated with death in pregnant women with severe pandemic H1N1 infection.DesignCase–control study.SettingAnhui, China.ParticipantsA total of 46 pregnant women with severe pandemic H1N1 infection were studied during June 2009–April 2011.Primary and secondary outcome measuresAll the cases were confirmed by the clinicians and epidemiologists together based on the positive laboratory result.ResultsOf the seven pregnant women who died of the pandemic H1N1 infection, five (70%) cases were in their third trimester. Twenty-nine (63%) cases from the surviving group were admitted to hospital within 3 days after the onset of symptoms, while only one (2%) case from the death group took the earliest admission 2 days after the onset. There was a significant difference on how soon to be admitted between the death and the surviving groups (OR 0.09, 95% CI 0.01 to 0.68). The median time of administrating corticosteroids was 5 days after the onset in the death group and 3 days in the surviving group showing no significant difference between them (p=0.056).ConclusionsFor the pregnant women with severe p(H1N1) infection, the risk factors associated with death were as follows: the delay of antiviral treatment and being in the third trimester. The corticosteroids therapy appeared to have no effects on preventing the cases from death.
Sedentary behaviour and life expectancy in the USA: a cause-deleted life table analysis
Authors: Katzmarzyk Peter T , Lee I-Min 
Published: July 2012

ObjectivesTo determine the impact of sitting and television viewing on life expectancy in the USA.DesignPrevalence-based cause-deleted life table analysis.SettingSummary RRs of all-cause mortality associated with sitting and television viewing were obtained from a meta-analysis of available prospective cohort studies. Prevalences of sitting and television viewing were obtained from the US National Health and Nutrition Examination Survey.Primary outcome measureLife expectancy at birth.ResultsThe estimated gains in life expectancy in the US population were 2.00 years for reducing excessive sitting to <3 h/day and a gain of 1.38 years from reducing excessive television viewing to <2 h/day. The lower and upper limits from a sensitivity analysis that involved simultaneously varying the estimates of RR (using the upper and lower bounds of the 95% CI) and the prevalence of television viewing (±20%) were 1.39 and 2.69 years for sitting and 0.48 and 2.51 years for television viewing, respectively.ConclusionReducing sedentary behaviours such as sitting and television viewing may have the potential to increase life expectancy in the USA.
Education-to-job mismatch and the risk of work injury
Authors: Premji Stephanie , Smith Peter M 
Published: July 2012

ObjectivesTo examine the association between education-to-job mismatch and work injury.MethodsCross-sectional data from the 2003 and 2005 Canadian Community Health Surveys (n=63 462) were used to examine the relationship between having an educational level that is incongruent with occupational skills requirements and the risk of sustaining a work injury requiring medical attention or a work-related repetitive movement injury (RMI). The effect on injury of the interaction of overeducation with recent immigrant status was also examined. Models were stratified by sex and adjusted for possible confounders. Occupational physical demands were conceptualised as a potential mediating variable.ResultsAfter adjustment for covariates, over-education was associated with work injury and RMI for both sexes. Adjustment for occupational demands attenuated the impact on work injury but did not eliminate the effect on RMI among men. The interaction of over-education and recent immigrant status resulted among men in a fourfold increase in the odds of work injury compared with non-recent immigrants who were not over-educated. After adjustment for occupational demands, over-educated recent immigrant men still had more than a twofold increase in the odds of injury.ConclusionsThe risk of sustaining a work injury is higher among those whose education exceeds that of job requirements. These findings highlight the need to address barriers to suitable employment, particularly among recent immigrants.