The contribution of neighbours to an individual's risk of typhoid outcome.

An individual's risk of infection from an infectious agent can depend on both the individual's own risk and protective factors and those of individuals in the same community. We hypothesize that an individual's exposure to an infectious agent is associated with the risks of infection of those living nearby, whether their risks are modified by pharmaceutical interventions or by other factors, because of the potential for transmission from them. For example, unvaccinated individuals living in a highly vaccinated community can benefit from indirect protection, or living near more children in a typhoid-endemic region (where children are at highest risk) might result in more exposure to typhoid. We tested this hypothesis using data from a cluster-randomized typhoid vaccine trial. We first estimated each individual's relative risk of confirmed typhoid outcome using their vaccination status and age. We defined a new covariate, potential exposure, to be the sum of the relative risks of all who live within 100 m of each person. We found that potential exposure was significantly associated with an individual's typhoid outcome, and adjusting for potential exposure affected estimates of vaccine efficacy. We suggest that it is useful and feasible to adjust for spatially heterogeneous distributions of individual-level risk factors, but further work is required to develop and test such approaches.

Risk factors for Japanese encephalitis: a case-control study.

Japanese encephalitis (JE) has been found to be endemic in Bali, Indonesia. A case-control study was conducted to identify factors associated with JE infection. All 94 serologically confirmed JE cases (cases) and 163 cases of encephalitis or aseptic meningitis without JE (controls) identified in Bali during 2001-2004 were included in the study. Potential risk factors were surveyed at hospital admission. Univariate analyses revealed the following factors to be associated with JE: older age, referral from sub-district health centre or private hospital, playing outdoors after dinner, use of mosquito repellent or spraying, proximity of the residence to rice fields, and pig ownership by the family or next-door neighbours. Multivariate analysis identified proximity to rice fields (OR 2.93, 95% CI 1.57-5.45), pig ownership (OR 2.24, 95% CI 1.17-4.26), and older age (OR 1.21, 95% CI 1.09-1.33) as being independently associated with the risk of JE. Because rice cultivation and pig rearing are essential to the economy of Bali, JE immunization is the best intervention for prevention of JE in Bali.

Antimicrobial resistance and subtyping of Salmonella enterica subspecies enterica serovar Enteritidis isolated from human outbreaks and poultry in southern Brazil.

To investigate antimicrobial resistance, 96 Salmonella enterica subspecies enterica serovar Enteritidis strains isolated from salmonellosis outbreaks and poultry-related products obtained in southern Brazil were analyzed. Macrorestriction patterns, obtained by pulsed-field gel electrophoresis and phage types, were assessed. Although 43.75% of samples were sensitive to all drugs tested, resistance to sulfonamide (34.37%), trimethoprim-sulfamethoxazole (25.00%), nalidixic acid (14.58%), streptomycin (2.08%), gentamicin, and tetracycline (1.04%) was identified. Furthermore, 89.60% of strains belonged to phage type 4, and a predominant pulsed-field gel electrophoresis genotype represented by 82.29% of the strains was identified, suggesting that a clonal group was distributed in poultry, food, and human isolates. Although it was not possible to associate strains from different sources, the occurrence of antimicrobial-resistant Salmonella Enteritidis strains supports the need to establish monitoring programs to identify the emergence of potential resistance patterns and to direct policies for use of these drugs in food-producing animals.

Author Correction: On the processes influencing rapid intensity changes of tropical cyclones over the Bay of Bengal.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Partial inversion of the initiation-promotion sequence of multistage tumorigenesis in the skin of NMRI mice.

Alterations in NMRI mouse skin induced by the phorbol ester 12-O-tetradecanoylphorbol-13-acetate in "stage I of tumor promotion" are slowly reversible, and this reversibility has a half-time of 10 to 12 weeks. The tumor response observed in the course of an initiation-promotion experiment in vivo is independent of whether stage I of promotion occurs before or after initiation. Since the time interval between treatment with the promoter, and subsequent initiation can be extended up to at least 6 weeks, an enhancement of initiation because of promoter-induced cellular DNA synthesis seems to be unlikely. This result may be inconsistent with the two-stage model of tumor promotion because it indicates that in skin the existence of initiated cells is not required for the induction of cellular alterations that are essential for the stage of skin tumorigenesis called stage I of promotion.

Tumor promotion by phorbol esters in skin: evidence for a memory effect.

By means of a two-stage promotion protocol in mouse epidermis with 12-O-tetradecanoylphorbol-13-acetate as first-stage promoter and 12-O-retinoylphorbol-13-acetate as second-stage promoter, the effects of the former that are critical and obligatory for tumor promotion were shown to be irreversible in nature for at least 8 weeks. The reversibility of tumor promotion was related to the second stage of promotion, reflecting the reversibility of epidermal hyperplasia induced by 12-O-tetradecanoylphorbol-13-acetate.

Pharmacological action of tick saliva upon haemostasis and the neutralization ability of sera from repeatedly infested hosts.

Ticks are blood-feeding arthropods widely distributed in the world and vectors of several diseases. As haematophagy demands evasion strategies and repeatedly infested hosts develop protective immune responses, we investigated the mechanisms of the Rhipicephalus (Boophilus) microplus saliva anti-haemostatic activity and the possible relationship between the acquired natural anti-tick host resistance and anti-haemostatic action. For this purpose, we studied the effects of R. microplus saliva on different pathways of haemostasis and tested whether repeated infested bovine sera (RIBS) are able to abolish salivary anti-haemostatic activities. R. microplus saliva (i) displays inhibitory activity upon collagen-induced platelet aggregation; (ii) inhibits the induction of endothelial pro-coagulant state; and (iii) reduces thrombogenesis in vivo. RIBS were shown to be able to partially block the delay of coagulation and the anti-thrombotic effect of saliva, and to totally abolish the modulation of endothelium activation. Conversely, RIBS has no effect on the inhibition of platelet aggregation. These results show, for the first time, the neutralization ability of sera from acquired resistance hosts against tick anti-haemostatics. Moreover, this is the first report of a haematophagous parasite able to modulate endothelial cell pro-coagulant state, and addresses the presence of anti-platelet and anti-thrombotic activity in R. microplus saliva.

Systemic alterations of bovine hemostasis due to Rhipicephalus (Boophilus) microplus infestation.

The tick Rhipicephalus (Boophilus) microplus is a hematophagous ectoparasite that causes considerable economic losses to cattle breeding. Although R. microplus saliva contains several molecules that interfere with the blood coagulation process, so far the systemic alterations in the host hemostatic system have not been described. This study aims to determine if R. microplus infestation induces any disturbance to the host's hemostatic system. To address these questions, six calves were experimentally infested with 20,000 R. microplus larvae and their blood was collected before and 7, 14 and 21 days post-infestation. Collagen and ADP-induced platelet aggregation as well as coagulation (activated partial thromboplastin time and prothrombin time) decreased in infested bovines. Platelet blood count and fibrinogen increased during the course of infestation, probably as a compensatory response. These alterations may play a role in host health status, and show that the host cannot fully counteract the tick anti-hemostatic mechanisms.

Protein kinase C activation by phorbol esters: do cysteine-rich regions and pseudosubstrate motifs play a role?

A model for the binding of two activators of protein kinase C (PKC), the phorbol ester 12-O-tetradecanoylphorbol-13-acetate (TPA) and diacylglycerol, to the enzyme is proposed. It is suggested that each activator is hydrogen-bonded to sulfhydryl groups of cysteine residues and to the carbonyl of an asparagine within the cysteine-rich regions of PKC. This might induce a conformational change that would disrupt the association of the inhibitory pseudosubstrate sequence with the active center of PKC.

On the processes influencing rapid intensity changes of tropical cyclones over the Bay of Bengal.

We present a numerical investigation of the processes that influenced the contrasting rapid intensity changes in Tropical Cyclones (TC) Phailin and Lehar (2013) over the Bay of Bengal. Our emphasis is on the significant differences in the environments experienced by the TCs within a few weeks and the consequent differences in their organization of vortex-scale convection that resulted in their different rapid intensity changes. The storm-relative proximity, intensity, and depth of the subtropical ridge resulted in the establishment of a low-sheared environment for Phailin and a high-sheared environment for Lehar. Our primary finding here is that in Lehar's sheared vortex, the juxtaposition in the azimuthal phasing of the asymmetrically distributed downward eddy flux of moist-entropy through the top of the boundary layer, and the radial eddy flux of moist-entropy within the boundary layer in the upshear left-quadrant of Lehar (40-80 km radius) establishes a pathway for the low moist-entropy air to intrude into the vortex from the environment. Conversely, when the azimuthal variations in boundary layer moist-entropy, inflow, and convection are weak in Phailin's low-sheared environment, the inflow magnitude and radial location of boundary layer convergence relative to the radius of maximum wind dictated the rapid intensification.

Healthcare utilisation patterns for respiratory and gastrointestinal syndromes and meningitis in Msunduzi municipality, Pietermaritzburg, KwaZulu-Natal Province, South Africa, 2013.

BACKGROUND: Public health facilities are used by the majority of South Africans, and healthcare utilisation surveys have been a useful tool to estimate the burden of disease in a given area. OBJECTIVES: To describe care-seeking behaviour in a periurban site with a high prevalence of HIV infection, as well as barriers to seeking appropriate healthcare. METHODS: We conducted a cross-sectional household survey in 22 wards of the Msunduzi municipality in KwaZulu-Natal Province, South Africa, from October to December 2013 using a simple random sample of households selected from a 2011 census enumeration. A primary caregiver/adult decision-maker was interviewed regarding demographic data as well as health status and recent self-reported episodes of selected illnesses and healthcare utilisation. RESULTS: Of the 2 238 eligible premises visited, 1 936 households (87%) with a total of 9 733 members were enrolled in the study. Of these, 635 (7%) reported one or more episodes of infectious illness during the study period. Public health clinics were most frequently consulted for all illnesses (361/635, 57%). Private healthcare (general practitioner, private clinic, private hospital) was sought by 90/635 of individuals (14%), only 13/635 (2%) reported seeking care from traditional healers, religious leaders or volunteers, and 71/635 (11%) did not seek any medical care for acute illnesses. Individuals in the lowest income group were more likely to seek care at public health facilities than those in the highest income group (70% v. 32%). CONCLUSIONS: Public health facility-based surveillance may be representative of disease patterns in this community, although surveillance at household level shows that high-income individuals may be excluded because they were more likely to use private healthcare, and the proportion of individuals who died at home would have been missed by facility-based surveillance. Data obtained in such surveys may be useful for public health planning.

An overview of the TROPICS NASA Earth Venture Mission.

The Time-Resolved Observations of Precipitation structure and storm Intensity with a Constellation of Smallsats (TROPICS) mission was selected by NASA as part of the Earth Venture-Instrument (EVI-3) program. The overarching goal for TROPICS is to provide nearly all-weather observations of 3D temperature and humidity, as well as cloud ice and precipitation horizontal structure, at high temporal resolution to conduct high-value science investigations of tropical cyclones. TROPICS will provide rapid-refresh microwave measurements (median refresh rate better than 60 min for the baseline mission) which can be used to observe the thermodynamics of the troposphere and precipitation structure for storm systems at the mesoscale and synoptic scale over the entire storm life cycle. TROPICS comprises six CubeSats in three low-Earth orbital planes. Each CubeSat will host a high-performance radiometer to provide temperature profiles using seven channels near the 118.75 GHz oxygen absorption line, water vapour profiles using three channels near the 183 GHz water vapour absorption line, imagery in a single channel near 90 GHz for precipitation measurements (when combined with higher-resolution water vapour channels), and a single channel near 205 GHz which is more sensitive to precipitation-sized ice particles. This observing system offers an unprecedented combination of horizontal and temporal resolution to measure environmental and inner-core conditions for tropical cyclones on a nearly global scale and is a major leap forward in the temporal resolution of several key parameters needed for assimilation into advanced data assimilation systems capable of utilizing rapid-update radiance or retrieval data. Launch readiness is currently projected for late 2019.

Induction of the formation of new hair follicles in mouse tail epidermis by the tumor promoter 12-O-tetradecanoylphorbol-13-acetate.

The formation of new hair follicles was quantitatively demonstrated in the tail skin of adult mice in the course of a two-stage carcinogenesis experiment with 7,12-dimethylbenz(a)anthracene as an initiator and the phorbol ester 12-O-tetradecanoylphorbol-13-acetate as a promoter, as well as in experiments with 12-O-tetradecanoylphorbol-13-acetate alone. Two kinds of follicular neogenesis could be distinguished. The most frequently encountered type was characterized by the organization of new follicles from the upper neck and orifice regions of already existing follicles. During their development, these new follicles remained in close apposition to the original follicles but, after having reached a critical size, split off to form fully independent follicles. In the second, type of follicular neogenesis, which occurred very rarely, the new follicles seemed to arise directly from the epidermis between two sets of hair triads; however, these follicles never reached their final stage and did not produce hairs. The formation of new hair follicles may be explained by a "dedifferentiation" of epidermal cells caused by the tumor promoter. Because of the paucity and advanced stage of the papillomas formed in tail skin after long-term treatment with 12-O-tetradecanoylphorbol-13-acetate, no reliable comment as to whether the papillomas derive from the hair follicles can be made.

Ornithine decarboxylase activity, cell proliferation, and tumor promotion in mouse epidermis in vivo.

The effect of different phorbol esters and of mechanical treatment on the activity of ornithine decarboxylase in mouse epidermis in vivo was investigated. The strong promoter 12-O-tetradecanoylphorbol-13-acetate as well as the weak promoters phorbol dibenzoate and the 12-O-tetradecanoylphorbol-13-acetate analog 12-O-tetradeca-2-cis, 4-trans-6,8-tetraenoylphorobol-13-acetate strongly increased the activity of the enzyme and the intraepidermal level of putrescine, with a maximum at 5 hr after application, when applied in doses which evoke comparable proliferative and irritant responses in skin. The hyperplasiogenic but nonirritant and almost nonpromoting 4-O-methyl ether of 12-O-tetradecanoylphorbol-13-acetate did not show such effects. Mechanical removal of the uppermost horny layer led to a considerable increase of ornithine decarboxylase activity after 4 to 8 hr, while skin massage showed only a minute effect under conditions in which both treatments exhibit about the same mitogenic efficiency. Neither manipulation promotes tumor development. After skin massage, the induction of ornithine decarboxylase was influenced neither by treatments which alter the cyclic adenosine 3',5'-monophosphate level in epidermis (inhibition of phosphodiesterase, beta-adrenergic stimulation, and injection of dibutyryl cyclic adenosine 3',5'-monophosphate) nor by injection of epidermal G1 chalone. The results indicate that no clear-cut correlation exists between epithelial cell proliferation, development of hyperplasia, and tumor promotion on the one hand and an activation of epidermal ornithine decarboxylase on the other.

Prostaglandin E-mediated mitogenic stimulation of mouse epidermis in vivo by divalent cation ionophore A 23187 and by tumor promoter 12-O-tetradecanoylphorbol-13-acetate.

When applied to mouse skin in vivo, both the strong tumor promoter 12-O-tetradecanoylphorbol-13-acetate (TPA) (2 nmol) and the divalent cation ionophore A 23187 (200 nmol) caused the same responses, i.e., skin inflammation and prostaglandin E2-mediated epidermal hyperplasia. In both cases, these events were accompanied by certain biochemical reactions in the epidermis such as an increase in the biosynthesis of and sensitivity to prostaglandin E2, increase in ornithine decarboxylase and phosphodiesterase activities, and refractoriness of cyclic adenosine 3':5'-monophosphate production to beta-adrenergic stimulation. In contrast to A 23187, TPA did not induce degranulation of mast cells; whereas, in contrast with TPA, A 23187 did not show tumor-promoting activity. These results indicate that the observed biological effects of TPA are no indication of tumor-promoting ability and that, on the other hand, the mitogenic effects of A 23187 are possibly not due to its properties as a calcium ionophore.

Radiomimetic activity of phorbol esters exerted in HeLa cells in comparison with their tumor-promoting capacity.

The biological activities exerted in mouse skin by three closely related phorbol esters were compared with the effects of these compounds on HeLa cells. The tumor promoter 12-O-tetradecanoylphorbol-13-acetate has been shown previously to influence various cell cycle parameters of these cells, thereby mimicking X-irradiation [Kinzel, V., Richards, J., and Stöhr, M. Science (Wash. D. C.), 210: 429-431, 1980]. Qualitatively similar effects were exerted by the mitogenic and irritant but almost nonpromoting "incomplete" phorbol esters 12-O-tetradeca-2-cis-4-trans-6,8-tetraenoylphorbol-13-acetate and 12-O-retinoylphorbol-13-acetate. Cell cycle parameters were analyzed by measuring thymidine incorporation rates, labeling indices, DNA histograms gained through flow cytometry, and mitotic activity. In every case, 12-O-tetradecanoylphorbol-13-acetate was more effective than 12-O-tetradeca-2-cis-4-trans-6,8-tetraenoylphorbol-13-acetate or 12-O-retinoylphorbol-13-acetate. The analysis of the influence of phorbol esters in G2 phase showed that, in order to reach the effectiveness of 10(-8) M 12-O-tetradecanoylphorbol-13-acetate, approximately 10 times the concentration of either 12-O-tetradeca-2-cis-4-trans-6,8-tetraenoylphorbol-13-acetate or 12-O-retinoylphorbol-13-acetate has to be applied. Therefore, the susceptibility of replicating HeLa cells to these phorbol derivatives reflects the promoting rather than the mitogenic and irritant capacity of these compounds.

Effects of phorbol esters on basal epidermal cells derived from ear skin of adult guniea pigs.

In cultures of basal epidermal cells obtained from ear skin of adult guinea pigs, the tumor-promoting phorbol ester 12-O-tetradecanoylphorbol-13-acetate induces cellular proliferation which is prostaglandin dependent and inhibited by indomethacin. Inhibition by indomethacin can be overcome by prostaglandins E2 and F2 alpha, with prostaglandin F2 alpha being more effective. The concomitant induction of ornithine decarboxylase activity is insensitive to indomethacin inhibition. The nonpromoting derivative 4-O-methyl-12-O-tetradecanoylphorbol-13-acetate evokes a prostaglandin-independent, i.e., indomethacin-insensitive, stimulation of cell proliferation without inducing ornithine decarboxylase activity.

Events associated with mouse skin tumor promotion with respect to arachidonic acid metabolism: a comparison between SENCAR and NMRI mice.

NMRI and SENCAR, two stocks of mice commonly used in multistage skin carcinogenesis studies, were compared with respect to the effects of inhibitors of arachidonic acid metabolism for the following 12-O-tetra-decanoylphorbol-13-acetate (TPA)-elicited events: tumor promotion, DNA synthesis in vivo and in vitro, ornithine decarboxylase induction, and prostaglandin (PG) E2 synthesis. Previous work had shown that the cyclooxygenase inhibitor indomethacin enhanced TPA promotion in SENCAR mice. We report here that over the same dose range (50 to 200 micrograms) indomethacin caused a dose-dependent inhibition of promotion in NMRI mice. Significant reversal of this inhibition was achieved with concomitant application of 10 micrograms PGF2 alpha but not PGE2. DNA synthesis studies showed that low doses of indomethacin and flurbiprofen increased TPA-stimulated DNA synthesis in primary cultures from SENCAR mice; indomethacin suppressed this response in NMRI cultures. In vivo DNA synthesis studies showed the same pattern: indomethacin enhanced TPA-stimulated DNA synthesis in SENCAR mice but inhibited in NMRI mice. Other classes of inhibitors of arachidonate metabolism (i.e., the cyclooxygenase-lipoxygenase inhibitors 5,8,11,14-eicosatetraynoic acid and phenidone and the phospholipase A2 inhibitor dibromoacetophenone) had inhibitory activity in vitro and in vivo in both stocks of mice. Indomethacin was found to inhibit TPA-induced ornithine decarboxylase activity to the same extent in both mice. Indomethacin was also very effective in inhibiting TPA-induced PGE2 synthesis in both stocks of mice. 5,8,11,14-Eicosatetraynoic acid and phenidone were likewise suppressive in both stocks of mice. It is concluded that the NMRI and SENCAR mice respond similarly to TPA with respect to promotion, DNA synthesis, ornithine decarboxylase induction, and PG synthesis. The difference appears to be in the degree of involvement of the lipoxygenase pathway.

Histone phosphorylation in phorbol ester stimulated and beta-adrenergically stimulated mouse epidermis in vivo and characterization of an epidermal protein phosphorylation system.

Under certain physiological conditions a change in the phosphorylation of histones in mouse epidermis in vivo was observed. Thus a single local application of the tumor-promoting mitogen 12-O-tetradecanoylphorbol-13-acetate caused a long-lasting increase of histone H1 phosphorylation which paralleled stimulated cell proliferation. Injection of the antimitotic beta-adrenergic agonist isoproterenol led to a temporary decrease in the rate of phosphorylation of H1, H2A and H2B immediately after cyclic AMP accumulation. A complete protein phosphorylation system could be demonstrated in mouse epidermis homogenates. The following enzyme activities were partially purified and characterized: a cyclic AMP-dependent histone kinase; a 'casein kinase' and an 'unspecific' protein kinase; a histone-specific protein phosphatase; and two 'unspecific' phosphoprotein phosphatases. In addition, a stimulatory effect of cyclic GMP on histone phosphorylation was observed. The enzymes were found to be predominantly localized in the 105000 X g supernatant, but a small proportion of protein kinase and phosphatase activity could be regularly demonstrated in cell nuclei.

Relationship between TGF alpha-induced DNA synthesis and prostaglandin synthesis in human HaCaT keratinocytes.

The relationship between transforming growth factor alpha (TGF alpha)-induced cell proliferation and prostaglandin synthesis was investigated using growth-arrested human keratinocytes of the HaCaT line. Depending on the TGF alpha concentration, the stimulation of DNA synthesis (5-fold) was found to be either insensitive (at < 10 ng/ml TGF alpha) or sensitive (at > or = 20 ng/ml TGF alpha) to inhibition by both indomethacin, an inhibitor of prostaglandin synthases (PGHS) 1 and 2 and the PGHS 2-specific inhibitor NS-398. Indomethacin-effected inhibition did not correlate with cytotoxicity and was restricted to a narrow time window after growth factor administration. The indomethacin- and NS-398-sensitive mitogenic effect of TGF alpha correlated with an early increase of arachidonic acid release and prostaglandin (PGE2, PGF2alpha) synthesis, whereas the PGHS inhibitor-insensitive TGF alpha effect did not. TGF alpha-induced prostaglandin synthesis was due to a growth factor-induced PGHS-2 activity as indicated by its suppression by NS-398. However, attempts to overcome the PGHS inhibitor-dependent suppression of TGF alpha-induced DNA synthesis by adding prostaglandins (E1, E2, F2alpha, G2) to the cultures proved to be unsuccessful. Thus, TGF alpha-induced synthesis of prostaglandins seems not to be involved in the mediation of the mitogenic effect of the growth factor on human keratinocytes in culture.