Alterations of neutrophil L-selection and CD18 expression by tobacco smoke: implications for periodontal diseases

Alterations in neutrophil functions by both chronic low levels of tobacco and by acute short-term higher levels of tobacco smoke, as encountered during the act of smoking, may play a role in the pathogenesis of periodontal diseases in smokers. Among the early migration events of neutrophil function is the alteration in surface expression of L-selectin and the CD11/18 integrins. In the present study we examined the effect of in vitro smoke exposure and nicotine alone on the expression of these 2 adhesion molecules in neutrophils from smokers and non-smokers. We also determined the physiological relevance of this in vitro system by assessing the levels of nicotine exposure in this in vitro system and comparing these levels to acute and chronic levels of nicotine in saliva and gingival crevicular fluid. Peripheral neutrophils were isolated from the blood of smokers (> 1 pack/d) and non-smokers and incubated in vitro with either cigarette smoke (0–5 min), 10^?7 M F-met-leu-phe, or nicotine alone at 1.62mg/ml to 162ng/ml (10^?2 M-10^?6 M). The neutrophils were then incubated with fluoresceine conjugated anti-Leu8 (L-selectin), anti-CD18 (CD18 integrin), or γ-4 (non-specific control), fixed and analyzed by flow cytometry. With cigarette smoke exposure, there was an approximate 75% shedding of L-selectin in both smokers and non-smokers with no marked difference between groups at 1–5 min of smoke exposure. Cigarette smoke exposure resulted in a 15–20% increase in CD 18 expression in both smokers and non-smokers. At all time points, there was slightly greater but statistically insignificant expression of CD18 integrin in non-smokers when compared to smokers. These patterns of CD18 increases and L-selectin shedding were similar in magnitude to incubations with 10^?7 M F-met-leu-phe. Acute smoke exposure resulted in elevation of nicotine in the smoke box to 529 ng/ml at 5 min, in saliva from 109.2 ng/ml before smoking to 1821.4 ng/ml after smoking, and in gingival crevicular fluid to 5961 ng/ml after smoking. No significant alterations in L-selectin or CD 18 expression were noted with in vitro nicotine from 1.62 mg/ml to 162 ng/ml.     

Defining causative factors contributing in the activation of hedgehog signaling in diffuse large B-cell lymphoma

Hedgehog (Hh) signaling pathway is activated in diffuse large B-cell lymphoma (DLBCL). Genetic abnormalities that explain activation of Hh signaling in DLBCL are unknown. We investigate the presence of amplifications of Hh genes that might result in activation of this pathway in DLBCL. Our data showed few extra copies of GLI1 and SMO due to chromosomal aneuploidies in a subset of DLBCL cell lines. We also showed that pharmacologic inhibition of PI3K/AKT and NF-κB pathways resulted in decreased expression of GLI1 and Hh ligands. In conclusion, our data support the hypothesis that aberrant activation of Hh signaling in DLBCL mainly results from integration of deregulated oncogenic signaling inputs converging into Hh signaling.     

Developmental changes in the hormonal identity of gonadotroph cells in the rhesus monkey pituitary gland

To help elucidate the regulatory mechanism responsible for divergent gonadotrophin secretion during sexual maturation, we examined the gonadotroph population and hormonal identity of gonadotroph subtypes in pituitary glands of juvenile (age, 1.7 +/- 0.2 yr) and adult (age, 12.3 +/- 0.8 yr) male rhesus monkeys (Macacca mulatta). Serum LH and testosterone concentrations were, respectively, 3 and 7 times lower in juveniles than in adults, thus confirming the different stages of development. Immunohistochemistry revealed that the proportion of LH gonadotrophs in relation to the total pituitary cell population in the juvenile animals was significantly smaller than in the adults. In a subsequent study, double immunofluorescent labeling identified three distinct gonadotroph subtypes in both age groups: ones expressing either LH or FSH and another one expressing a combination of both gonadotrophins. Whereas the number of monohormonal LH cells per unit area was greater in the adults than in the juveniles, the number of monohormonal FSH gonadotrophs was remarkably lower. However, the proportion of FSH cells (whether mono- or bihormonal) within the gonadotroph population was similar between groups. Interestingly, the proportion and number of bihormonal gonadotrophs as well as the LH/FSH gonadotroph ratio were significantly greater in the adults than in the juveniles. Taken together, these data reveal that during the juvenile-adult transition period, not only does the pituitary gonadotroph population increase, but a large number of monohormonal FSH gonadotrophs are likely to become bihormonal. Because this morphological switch occurs when marked changes in plasma gonadotrophins are known to occur, it may represent an intrapituitary mechanism that differentially regulates gonadotrophin secretion during sexual development.     

Alterations of neutrophil l-selectin and CD18 expression by tobacco smoke: implications for periodontal diseases

Alterations in neutrophil functions by both chronic low levels of tobacco and by acute short-term higher levels of tobacco smoke, as encountered during the act of smoking, may play a role in the pathogenesis of periodontal diseases in smokers. Among the early migration events of neutrophil function is the alteration in surface expression of L-selectin and the CD11/18 integrins. In the present study we examined the effect of in vitro smoke exposure and nicotine alone on the expression of these 2 adhesion molecules in neutrophils from smokers and non-smokers. We also determined the physiological relevance of this in vitro system by assessing the levels of nicotine exposure in this in vitro system and comparing these levels to acute and chronic levels of nicotine in saliva and gingival crevicular fluid. Peripheral neutrophils were isolated from the blood of smokers (< 1 pack/d) and non-smokers and incubated in vitro with either cigarette smoke (0-5 min), 10^?7 M F-met-leu-phe, or nicotine alone at 1.62 mg/ml to 162 ng/ml (10^?2 M-10^?6 M). The neutrophils were then incubated with fluoresceine conjugated anti-Leu8 (L-selectin), anti-CD 18 (CD 18 integrin), or γ-4 (non-specific control), fixed and analyzed by flow cytometry. With cigarette smoke exposure, there was an approximate 75% shedding of L-selectin in both smokers and non-smokers with no marked difference between groups at 1-5 min of smoke exposure. Cigarette smoke exposure resulted in a 15-20% increase in CD18 expression in both smokers and non-smokers. At all time points, there was slightly greater but statistically insignificant expression of CD 18 integrin in non-smokers when compared to smokers. These patterns of CD 18 increases and L-selectin shedding were similar in magnitude to incubations with 10^?7 M F-met-leu-phe. Acute smoke exposure resulted in elevation of nicotine in the smoke box to 529 ng/ml at 5 min, in saliva from 109.2 ng/ml before smoking to 1821.4 ng/ml after smoking, and in gingival crevicular fluid to 5961 ng/ml after smoking. No significant alterations in L-selectin or CD 18 expression were noted with in vitro nicotine from 1.62 mg/ml to 162 ng/ml.     

Scale and tooth phenotypes in medaka with a mutated ectodysplasin-A receptor: implications for the evolutionary origin of oral and pharyngeal teeth

Ectodermal contribution to the induction of pharyngeal teeth that form in the endodermal territory of the oropharyngeal cavity in some teleost fishes has been a matter of considerable debate. To determine the role of ectodermal cell signaling in scale and tooth formation and thereby to gain insights in evolutionary origin of teeth, we analyzed scales and teeth in rs-3 medaka mutants characterized by reduced scale numbers due to aberrant splicing of the ectodysplasin-A receptor (edar). Current data show that, in addition to a loss of scales (83% reduction), a drastic loss of teeth occurred in both oral (43.5% reduction) and pharyngeal (73.5% reduction) dentitions in rs-3. The remaining scales of rs-3 were irregular in shape and nearly 3 times larger in size relative to those of the wild-type. In contrast, there was no abnormality in size and shape in the remaining teeth of rs-3. In wild-type medaka embryos, there was a direct contact between the surface ectoderm and rostral endoderm in pharyngeal regions before the onset of pharyngeal tooth formation. However, there was no sign of ectodermal cell migration in the pharyngeal endoderm and hence no direct evidence of any ectodermal contribution to pharyngeal odontogenesis. These data suggest differential roles for Eda-Edar signaling in the induction and growth of scales and teeth and support the intrinsic odontogenic competence of the rostral endoderm in medaka.     

Assessment of unmet needs to address noncompliant households during polio supplemental immunization activities in Kaduna state, 2014–2016

Background

Despite concerted global efforts being made to eradicate poliomyelitis, the wild poliovirus still circulates in three countries, including Nigeria. In addition, Nigeria experiences occasional outbreaks of the circulating vaccine-derived poliovirus type 2 (cVDPV2). Vaccine rejection by caregivers persists in some parts of northern Nigeria, which compromises the quality of supplemental immunization activities (SIAs). In 2013, the Expert Review Committee (ERC) on polio recommended innovative interventions in all high-risk northern states to improve the quality of SIA rounds through innovative interventions. The study assessed the impact of using unmet needs data to develop effective strategies to address noncompliant households in 13 high-risk Local government areas (LGAs) in Kaduna state, Nigeria.

Methods

A retrospective study was conducted in noncompliant communities using unmet needs data collated from 2014 to 2016. Household-based noncompliance data collated from tally sheets between 2013 and 2016 was also analyzed to assess the impact of unmet needs data in addressing noncompliance households in high-risk communities in Kaduna state. A structured interview was used to interview caregivers by the application of an unmet needs questionnaire, a quantitative study that assesses caregiver perception on immunization and other unmet needs which, if the gaps were addressed, would allow them to accept immunization services. Interventions include siting of temporary health camps in noncompliant communities to provide free medical consultations, treatment of minor ailments, provision of free antimalaria drugs and other essential drugs, and also referral of serious cases; intervention of religious and traditional leaders, youth against polio intervention, and the use of attractive bonuses (sweets, balloons, milk) during SIAs were all innovations applied to reduce noncompliance in households in affected communities as the need for eradication of polio was declared as a state of emergency. Outcomes from the analyses of unmet needs data were used to direct specific interventions to certain areas where they will be more effective in reducing the number of noncompliant households recorded on the tally sheet in each SIA round. Hence, seven immunization parameters were assessed from the unmet needs data.

Results

Overall, 54% of the noncompliant caregivers interviewed were ready to support immunization services in their communities. The majority of caregivers were also willing to vaccinate their children publicly following unmet needs interventions that were conducted in noncompliant communities. The trend of noncompliant households decreased by 79% from 16,331 in September 2013 to 3394 in May 2016.

Conclusions

Unmet needs interventions were effective in reducing the number of noncompliant households recorded during SIA rounds in Kaduna State. Hence, unmet needs intervention could be adapted at all levels to address challenges faced in other primary healthcare programs in Nigeria.

     

Tree diversity does not always improve resistance of forest ecosystems to drought

Climate models predict an increase in the intensity and frequency of drought episodes in the Northern Hemisphere. Among terrestrial ecosystems, forests will be profoundly impacted by drier climatic conditions, with drastic consequences for the functions and services they supply. Simultaneously, biodiversity is known to support a wide range of forest ecosystem functions and services. However, whether biodiversity also improves the resistance of these ecosystems to drought remains unclear. We compared soil drought exposure levels in a total of 160 forest stands within five major forest types across Europe along a gradient of tree species diversity. We assessed soil drought exposure in each forest stand by calculating the stand-level increase in carbon isotope composition of late wood from a wet to a dry year (Δδ¹³C_S). Δδ¹³C_S exhibited a negative linear relationship with tree species diversity in two forest types, suggesting that species interactions in these forests diminished the drought exposure of the ecosystem. However, the other three forest types were unaffected by tree species diversity. We conclude that higher diversity enhances resistance to drought events only in drought-prone environments. Managing forest ecosystems for high tree species diversity does not necessarily assure improved adaptability to the more severe and frequent drought events predicted for the future.Biodiversity plays an important role in ecosystem functioning by promoting a wide range of functions and services (1–3). This beneficial effect of biodiversity is determined by mechanistic processes directly under the influence of species interactions: complementarity among species for resource use through ecological niche partitioning and/or facilitation processes increase ecosystem performance because resources are better shared among neighboring species and are thus potentially more available (4). Previous studies have demonstrated that, apart from enhancing performance, diverse terrestrial ecosystems may also be more resilient and more resistant to biotic stresses such as insect pests or diseases (5, 6). However, it remains unclear whether higher biodiversity also leads to improved resistance of terrestrial ecosystems to the more frequent droughts expected in temperate regions (7). The rare case studies published thus far have shown contrasting results. Two reported that species in more diverse ecosystems could be more resistant to drought stress (8, 9), whereas another suggested that enhanced biodiversity could trigger higher exposure to drought (10). Improving our understanding of how species diversity influences the resistance of terrestrial ecosystems to a fluctuating climate is crucial.More frequent and intense droughts will greatly affect the carbon and water cycles of the terrestrial biosphere (11), in particular in forested ecosystems (12). Many societies around the world rely on forests for essential services such as wood production, hunting, or watershed protection. We therefore urgently need to improve our knowledge of the physiological response of these ecosystems to drier climatic conditions to propose new climate-smart management options. Forests, although influenced by local environmental conditions, play a major role in the global carbon and water balance as they release into and assimilate from the atmosphere huge amounts of CO₂ while losing water vapor through transpiration. Tree species are known to vary widely in the ecological strategies they use to deal with drought stress. It could therefore be expected that in highly diverse forests composed of tree species with contrasting functional traits, limited water resources could be better partitioned among the neighboring species as a result of complementarity and facilitation processes (4). Such forests should be more resistant to deal with drought stress because the trees should be able to maintain better access to diminishing water resources as the drought progresses. In contrast, if the interacting species in a diverse forest have similar functional traits (i.e., functional redundancy), ecological niche overlap (13) may lead to more stressful conditions during drought than in pure stands due to lower water availability for each species.Carbon isotope composition in C₃ plant tissues (δ¹³C) provides an integrated record of the ratio of intercellular to atmospheric CO₂ concentrations during the period when the carbon was fixed and thus reflects the balance between net CO₂ assimilation and stomatal conductance (14). Plants typically react toward drought stress by closing their stomata and reducing carbon assimilation rates. However, leaf stomatal conductance is affected to a greater extent than assimilation, causing a concomitant increase in δ¹³C (14, 15). Therefore, under soil drought conditions, δ¹³C from organic material has been widely accepted as an indicator of the intensity of drought exposure in plants (16, 17) (SI Text). If complementarity for water use is occurring among species, δ¹³C values should increase less between wet and dry soil conditions with increasing tree species diversity (i.e., a negative relationship). Inversely, if tree species occupy redundant ecological niches, δ¹³C values should either have a similar or higher increase between wet and dry conditions with increasing tree species diversity (i.e., a null or positive relationship).In a previous study, we analyzed the influence of drought on the relationship between tree species diversity and the increase in stand-level carbon isotope composition between a wet and dry year (Δδ¹³C_S) in boreal forests (10). Species diverse forests were shown to be more affected by drought stress than less diverse ones (i.e., a positive relationship between Δδ¹³C_S and tree species diversity). In the present study, we extend our research to five major forest types across Europe, which extends from northern hemiboreal forests to southern Mediterranean forests (Table S1). Our objective was to test whether the relationship between Δδ¹³C_S and tree species diversity would be consistent across a large range of climatic and edaphic conditions. At each of the five study sites, we selected a set of representative canopy trees (Table S2) in 21–42 forest stands varying in tree species diversity. For each site, we used a water balance modeling approach to select 1 y within the last 14 y with high drought stress and 1 reference y when no drought occurred (Figs. S1 and S2). We measured the δ¹³C in the tree rings of the selected canopy trees and calculated Δδ¹³C_S for each stand.