Fear extinction rescuing effects of dopamine and L-DOPA in the ventromedial prefrontal cortex.

The ventromedial prefrontal cortex (vmPFC; rodent infralimbic cortex (IL)), is posited to be an important locus of fear extinction-facilitating effects of the dopamine (DA) bio-precursor, L-DOPA, but this hypothesis remains to be formally tested. Here, in a model of impaired fear extinction (the 129S1/SvImJ inbred mouse strain; S1), we monitored extracellular DA dynamics via in vivo microdialysis in IL during fear extinction and following L-DOPA administration. Systemic L-DOPA caused sustained elevation of extracellular DA levels in IL and increased neuronal activation in a subpopulation of IL neurons. Systemic L-DOPA enabled extinction learning and promoted extinction retention at one but not ten days after training. Conversely, direct microinfusion of DA into IL produced long-term fear extinction (an effect that was insensitive to ɑ-/ß-adrenoreceptor antagonism). However, intra-IL delivery of a D1-like or D2 receptor agonist did not facilitate extinction. Using ex vivo multi-electrode array IL neuronal recordings, along with ex vivo quantification of immediate early genes and DA receptor signalling markers in mPFC, we found evidence of reduced DA-evoked mPFC network responses in S1 as compared with extinction-competent C57BL/6J mice that were partially driven by D1 receptor activation. Together, our data demonstrate that locally increasing DA in IL is sufficient to produce lasting rescue of impaired extinction. The finding that systemic L-DOPA increased IL DA levels, but had only transient effects on extinction, suggests L-DOPA failed to reach a threshold level of IL DA or produced opposing behavioural effects in other brain regions. Collectively, our findings provide further insight into the neural basis of the extinction-promoting effects of DA and L-DOPA in a clinically relevant animal model, with possible implications for therapeutically targeting the DA system in anxiety and trauma-related disorders.

Arbovirus vectors of epidemiological concern in the Americas: A scoping review of entomological studies on Zika, dengue and chikungunya virus vectors.

BACKGROUND: Three arthropod-borne viruses (arboviruses) causing human disease have been the focus of a large number of studies in the Americas since 2013 due to their global spread and epidemiological impacts: Zika, dengue, and chikungunya viruses. A large proportion of infections by these viruses are asymptomatic. However, all three viruses are associated with moderate to severe health consequences in a small proportion of cases. Two mosquito species, Aedes aegypti and Aedes albopictus, are among the world's most prominent arboviral vectors, and are known vectors for all three viruses in the Americas. OBJECTIVES: This review summarizes the state of the entomological literature surrounding the mosquito vectors of Zika, dengue and chikungunya viruses and factors affecting virus transmission. The rationale of the review was to identify and characterize entomological studies that have been conducted in the Americas since the introduction of chikungunya virus in 2013, encompassing a period of arbovirus co-circulation, and guide future research based on identified knowledge gaps. METHODS: The preliminary search for this review was conducted on PubMed (National Library of Health, Bethesda, MD, United States). The search included the terms 'zika' OR 'dengue' OR 'chikungunya' AND 'vector' OR 'Aedes aegypti' OR 'Aedes albopictus'. The search was conducted on March 1st of 2018, and included all studies since January 1st of 2013. RESULTS: A total of 96 studies were included in the scoping review after initial screening and subsequent exclusion of out-of-scope studies, secondary data publications, and studies unavailable in English language. KEY FINDINGS: We observed a steady increase in number of publications, from 2013 to 2018, with half of all studies published from January 2017 to March 2018. Interestingly, information on Zika virus vector species composition was abundant, but sparse on Zika virus transmission dynamics. Few studies examined natural infection rates of Zika virus, vertical transmission, or co-infection with other viruses. This is in contrast to the wealth of research available on natural infection and co-infection for dengue and chikungunya viruses, although vertical transmission research was sparse for all three viruses.

Comparison of wet brewers' grains or dried distillers' grains as supplements to conserved bermudagrass forage as winter feeding options for beef cows.

The objective of this study was to examine the use of 2 byproduct supplements and conserved warm-season forage as winter feeding options for primiparous beef cows. Gestating Angus ( = 48) and Brangus ( = 24) 2-yr-old cows were stratified by BW and breed to 1 of 12 pens. Pens were randomly assigned 1 of 2 supplements, wet brewers' grains (WBG) or dried distillers' grains (DDG). Coastal bermudagrass hay or round bale silage (RBS) was fed free choice (6 pens each) and cows received WBG or DDG supplements at a daily rate of 0.05% BW (DM basis) prorated for feeding 3 d/wk. Total BW and BCS changes did not differ ( = 0.65 and = 0.93, respectively) between DDG- and WBG-supplemented cows. Total amount of forage DM offered and mean calculated daily forage DM offered did not differ ( = 0.59 and = 0.20, respectively) between supplement treatments. Estimated daily mean and total supplement DM offered was greater ( < 0.001) for WBG than for DDG treatments. The same 2 supplements and forage sources were used in an unbalanced 6 × 4 design to measure intake, digestibility, and rumen parameters in ruminally fistulated steers. Supplement did not affect forage DMI of hay ( = 0.31) or RBS ( = 0.63). Total DMI was not different ( = 0.37 and = 0.73) for hay-based and RBS-based diets, respectively. Total tract digestibility tended to be greater ( = 0.06) for DDG than for WBG in hay diets but was not different ( = 0.76) for RBS diets. Daily mean ruminal pH was greater ( = 0.03) for WBG than for DDG when supplemented to hay-based diets. In RBS diets, a supplement × hour interaction ( = 0.05) existed for ruminal pH. Daily mean ruminal ammonia N concentration was greater ( < 0.001) for WBG-supplemented diets compared with DDG-supplemented diets. A supplement × hour interaction existed for ruminal ammonia in hay- ( < 0.001) and RBS- ( = 0.09) based diets. Ruminal pH and ammonia N concentrations stayed in ranges adequate to support ruminal metabolism and cattle performance. Marginal differences in ruminal measures between high-moisture and dry byproduct supplements resulted in no differences in cow performance when offered with hay or high-moisture forage. High-moisture forage sources can be coupled with high-moisture byproduct supplements.

Smoking-related cotinine levels and host responses in chronic periodontitis.

BACKGROUND AND OBJECTIVE: Smoking has been reported to increase the risk of periodontal disease by disrupting the balance of immune responses and tissue repair processes; however, this risk varies among smokers. Cotinine levels in saliva are routinely used to measure the level of smoking, and reflect the quantity of nicotine, and other smoking-related xenobiotics that challenge host systems. This study delineated characteristics of inflammatory mediators in saliva and serum antibody responses to both periodontal pathogens and commensal bacteria in smokers as they related to cotinine levels. MATERIALS AND METHODS: This case-control study (n = 279) examined salivary inflammatory mediator responses [interleukin (IL)-1ß, IL-10, prostaglandin E2, myeloperoxidase and plasminogen activator inhibitor-1], and serum IgG antibody responses to three periodontal pathogens (Aggregatibacter actinomyce-temcomitans, Porphyromonas gingivalis, Treponema denticola) and five commensal oral microorganisms (Veillonella parvula, Streptococcus sanguis, Prevotella loescheii, Actinomyces naeslundii, Capnocytophaga ochracea). RESULTS: The patients were stratified into health (n = 30), gingivitis (n = 55) and periodontitis (n = 184); cotinine levels correlated with reported smoking habits in health, less so with gingivitis, and were not correlated in periodontitis. Of the inflammatory mediators/acute phase proteins, only IL-1ß levels were positively associated (p < 0.001) with the pack years and cotinine levels. As might be predicted, patients with periodontitis smoked more (p < 0.001) and had higher levels of cotinine. IL-1ß and antibody to A. actinomycetemcomitans, P. gingivalis and T. denticola were significantly higher in the patients with periodontitis than either patients with gingivitis or who were healthy. CONCLUSIONS: Generally, antibody to the pathogens and commensals was lower with decreased cotinine levels. Smoking exacerbated differences in both inflammatory mediators and three antibody in periodontal disease compared to healthy subjects.

Grape seed extract reduces the severity of selected disease markers in the proximal colon of dextran sulphate sodium-induced colitis in rats.

BACKGROUND: Grape seed extract (GSE) constitutes a rich source of procyanidins. GSE has been demonstrated to exert encouraging anti-inflammatory and anti-ulcer properties in experimental settings, although its effects on inflammation of the colon remain undefined. AIM: To determine the effects of GSE in a rat model of dextran sulphate sodium (DSS) for ulcerative colitis. METHODS: Male Sprague-Dawley rats were gavaged daily (days 0-10) with GSE (400 mg/kg). Ulcerative colitis was induced by substituting DSS (2 % w/v) for drinking water from days 5-10. A sucrose breath test was performed on day 11 to determine small bowel function and intestinal tissues were collected for histological analyses. Statistical analysis was by one-way or repeated-measures ANOVA and p < 0.05 was considered significant. RESULTS: Compared to DSS-treated controls, GSE significantly decreased ileal villus height (14 %; p < 0.01) and mucosal thickness (13 %; p < 0.01) towards the values of normal controls. GSE reduced qualitative histological severity score (p < 0.05) in the proximal colon, although no significant effect was evident in the distal colon. However, GSE failed to prevent DSS-induced damage to the crypts of both colonic regions. Administration of GSE did not negatively impact metabolic parameters, nor did it induce any deleterious gastrointestinal side effects in healthy animals. CONCLUSIONS: GSE decreased the severity of selected markers of DSS-induced colitis in the distal ileum and proximal colon, suggesting the potential as an adjuvant therapy for the treatment of ulcerative colitis. Future studies of GSE should investigate alternative delivery methods and treatment regimens, further seeking to identify the individual bioactive factors.

Bone remodeling-associated salivary biomarker MIP-1α distinguishes periodontal disease from health.

BACKGROUND AND OBJECTIVE: The field of salivary diagnostics lacks an accepted and validated biomarker of alveolar bone remodeling. To address this, we examined levels of salivary biomolecules specifically associated with biological aspects of bone remodeling in subjects with chronic periodontitis in a case-control study. MATERIAL AND METHODS: Levels of macrophage inflammatory protein-1α (MIP-1α), osteoprotegerin, C-telopeptide pyridinoline cross-links of type I collagen and ß-C-terminal type I collagen telopeptide in unstimulated whole saliva of 80 subjects (40 subjects with moderate to severe chronic periodontitis and 40 sex- and age-matched healthy control subjects) were measured using enzyme immunosorbent assays. Saliva was collected before clinical examination, which included probing depth, clinical attachment loss and bleeding on probing. RESULTS: The mean level of MIP-1α in subjects with periodontitis was 18-fold higher than in healthy subjects (p < 0.0001). Clinical periodontal indices correlated significantly with MIP-1α levels (p < 0.0001). Of the biomolecules examined, MIP-1α demonstrated the greatest ability to discriminate between periodontal disease and health as determined by the area under the curve (0.94) and classification and regression tree analysis (sensitivity 94% and specificity 92.7%). Osteoprotegerin levels were elevated 1.6-fold (p = 0.055), whereas C-telopeptide pyridinoline cross-links of type I collagen and ß-C-terminal type I collagen telopeptide levels were below the level of detection in the majority of subjects. CONCLUSION: These findings suggest that the chemokine MIP-1α may aid in identifying periodontitis. Future longitudinal studies are warranted to determine whether this biomarker can help in ascertaining the progression of bone loss in subjects with periodontal disease.

Smoking and periodontal disease: discrimination of antibody responses to pathogenic and commensal oral bacteria.

Smoking is an independent risk factor for the initiation, extent and severity of periodontal disease. This study examined the ability of the host immune system to discriminate commensal oral bacteria from pathogens at mucosal surfaces, i.e. oral cavity. Serum immunoglobulin (Ig)G antibody reactive with three pathogenic and five commensal oral bacteria in 301 current smokers (age range 21-66 years) were examined by enzyme-linked immunosorbent assay. Clinical features of periodontal health were used as measures of periodontitis. Antibody to the pathogens and salivary cotinine levels were related positively to disease severity; however, the antibody levels were best described by the clinical disease unrelated to the amount of smoking. The data showed a greater immune response to pathogens than commensals that was related specifically to disease extent, and most noted in black males. Significant correlations in individual patient responses to the pathogens and commensals were lost with an increasing extent of periodontitis and serum antibody to the pathogens. Antibody to Porphyromonas gingivalis was particularly distinct with respect to the discriminatory nature of the immune responses in recognizing the pathogens. Antibody responses to selected pathogenic and commensal oral microorganisms differed among racial groups and genders. The antibody response to the pathogens was related to disease severity. The level of antibody to the pathogens, and in particular P. gingivalis, was correlated with disease severity in black and male subsets of patients. The amount of smoking did not appear to impact directly serum antibody levels to these oral bacteria.

Infection, inflammation, and bone regeneration: a paradoxical relationship.

Various strategies have been developed to promote bone regeneration in the craniofacial region. Most of these interventions utilize implantable materials or devices. Infections resulting from colonization of these implants may result in local tissue destruction in a manner analogous to periodontitis. This destruction is mediated via the expression of various inflammatory mediators and tissue-destructive enzymes. Given the well-documented association among microbial biofilms, inflammatory mediators, and tissue destruction, it seems reasonable to assume that inflammation may interfere with bone healing and regeneration. Paradoxically, recent evidence also suggests that the presence of certain pro-inflammatory mediators is actually required for bone healing. Bone injury (e.g., subsequent to a fracture or surgical intervention) is followed by a choreographed cascade of events, some of which are dependent upon the presence of pro-inflammatory mediators. If inflammation resolves promptly, then proper bone healing may occur. However, if inflammation persists (which might occur in the presence of an infected implant or graft material), then the continued inflammatory response may result in suboptimal bone formation. Thus, the effect of a given mediator is dependent upon the temporal context in which it is expressed. Better understanding of this temporal sequence may be used to optimize regenerative outcomes.

Mechanical and degradation behavior of polymer-calcium sulfate composites.

Calcium sulfate (CS) is one of the oldest bone graft materials still in use. Its main limitations are poor handling characteristics, poor mechanical properties, and a resorption rate that is too fast for some applications. The present study investigated the effect of viscous polymers, such as carboxymethylcellulose (CMC) and hyaluronan (HY), on the handling characteristics, mechanical properties, and degradation behavior of CS. CMC and HY were added to CS at concentrations from 1-10 wt%. Addition of CMC to CS at more than 4 wt% produced a putty-like material and decreased the density of the composite, while also increasing flexural and compressive strength at higher loadings. Incorporation of CMC produced a concentration-dependent increase in water absorption and degradation rate. At an equivalent loading, HY-containing CS composites showed better compressive strength than CS with CMC. Overall, addition of CMC or HY to CS resulted in composite materials with better handling characteristics and improved mechanical properties after set, however the degradation rate of the augmented materials was increased. These properties suggest that the enhanced CS materials may be useful in certain clinical situations, such as filling non-uniform bone defects and situations that require mechanical integrity of the bone graft substitute during implantation.

Leprosy affected beggars as a hidden source for transmission of leprosy.

BACKGROUND & OBJECTIVES: Despite the large scale implementation of multidrug therapy (MDT), the incidence rates of leprosy have not declined in several hyperendemic countries. Before searching for non-human reservoirs of leprosy it would be necessary to look for hidden human sources. This would include destitute leprosy affected persons who resort to begging and operate in congested areas. Hence this study was undertaken. METHODS: One major town and three semi-urban areas in Vellore district of Tamil Nadu and Chittoor town in Andhra Pradesh were purposefully selected for the study. All beggars in these towns were systematically identified and examined by allopathic doctors. Skin smears were examined for bacteriological index. RESULTS: Among the 193 beggars screened, 58 had leprosy. Of these 10 were smear positive. Several beggars, although living separately, were in touch with their relatives. Most beggars were pavement dwellers and regularly begged at places of worship, bus stands and shopping centres. INTERPRETATION & CONCLUSION: The fact that nearly 20 per cent of the leprosy affected beggars were skin smear positive highlights the need for regular screening and treatment of such beggars. Those positive should be actively treated and their close contacts frequently screened. This hidden reservoir should be completely eliminated.

Expression of two nuclear genes encoding chloroplast proteins during early development of cucumber seedlings.

Cloned complementary DNA probes have been used to measure steady-state transcript levels for the small subunit of ribulose bisphosphate carboxylase-oxygenase (SSU) and the chlorophyll a/b-binding protein (LHCP) in cotyledons during early development of cucumber seedlings. Initial accumulation of trancripts to SSU occurs 2d after germination and is independent of light and developmentally programmed. Although transcripts accumulate in dark-grown tissues, their levels increase rapidly in light-grown cotyledons from day 4, coinciding with emergence above the soil, so that by day 6 levels are 2.4 times higher in light-grown compared with dark-grown cotyledons. In contrast, accumulation of transcripts to LHCP occurs only in light-grown cotyledons. Southern blot analysis of genomic DNA indicates that in cucumber there are one and two genes encoding SSU and LHCP, respectively, considerably fewer than in those other plant species that have been examined. Both LHCP genes are expressed in light-grown cotyledons.

Light and electron microscopic examinations of methane-producing biofilms from anaerobic fixed-bed reactors.

Ultrastructural examinations were performed on biofilms from eight anaerobic fixed-bed reactors filled with various packing materials and operated on fresh swine waste. By using light, UV, scanning, and transmission electron microscopy, the distribution of a diverse microbial population composed of bacteria and a few yeasts was determined. This is the first time that the ultrastructure of in situ anaerobic digestor biofilms has been reported. A large number of methanogenic bacteria were identified by their fluorescence under 420 nm of radiation. Of these, two morphologically distinct types were most prevalent in the films. Methanothrix spp. was present in high numbers at the film surface, whereas Methanosarcina spp. were commonly embedded in the lower regions of the film. Inhabitants of the film were surrounded by an exopolysaccharide matrix that was very dense toward the base. An extensive network of channels was observed throughout the matrix that may facilitate gas and nutrient exchange to the lower regions of the film.

Voltage-clamp analysis of a calcium-mediated potassium conductance in cockroach (Periplaneta americana) central neurones.

The electrical properties of motoneurone cell bodies in the metathoracic ganglion of the cockroach, Periplaneta americana, have been studied by the voltage-clamp technique. Most experiments were carried out on a single identified cell (cell 28), the cell body of which, as for most other insect motoneurones, is electrically inexcitable. For comparison, some experiments were also carried out on dorsal unpaired median (d.u.m.) cells, the cell bodies of which are excitable. The two cell types differed only in that the d.u.m. cells developed a transient net inward current when depolarized towards zero membrane potential. This current was reduced but not abolished by Ca-free saline. Both cell types had an N-shaped current-voltage relation, as typically seen for molluscan and other neurones, but the location of the falling phase of the relation showed an unusually strong time dependence. The N-shape was abolished by prolonged exposure to Ca-free saline, suggesting it to be due to a K conductance that was activated by the entry of Ca ions through voltage-dependent channels. An outward current was also elicited by ionophoretic injection of Ca ions. The reversal potential of this current varied with the saline K concentration, in the manner expected if the current was carried by K ions. The Ca-mediated K current was blocked by La ions and by the organic Ca antagonist D-600. A series of double-pulse experiments on voltage-clamped cell bodies of cell 28 suggested that very short periods of Ca entry were sufficient to activate the K conductance fully. These experiments also suggested that the K conductance activation was due to intracellular Ca accumulation rather than to its being directly linked to the inward Ca current. The activation of the K conductance by intracellular Ca ions was made more effective by cell membrane depolarization. The Ca-mediated conductance did not inactivate significantly under conditions in which substantial inactivation has been observed in other neurones. The physiological significance of the electrical properties of cell 28 is discussed.