Identifying keystone connectivity spots under climate change: Implications to conservation and management of riparian systems

Climate change has intensified the effects of habitat fragmentation in many ecosystems, particularly exacerbated in riparian habitats. Therefore, there is an urgent need to identify keystone connectivity spots to ensure long-term conservation and sustainable management of riparian systems as they play a crucial role for landscape connectivity. This paper aims to identify critical areas for connectivity under two contrasting climate change scenarios (RCP 4.5 and RCP 8.5 models) for the years 2030, 2050 and 2100 and to group these critical areas by similar connectivity in keystone spots for sustainable management. A set of analyses comprising climate analysis, drainage network analysis, configuration of potential riparian habitats, riparian habitat connectivity, data clustering, and statistical analysis within a Spanish river basin (NW Spain) were applied. The node and link connectivity would be reduced under the two climate change scenarios (≈2.5 % and 4.4 % reduction, respectively), intensifying riparian habitat fragmentation. Furthermore, 51 different clusters (critical areas) were obtained and classified in five classes (keystone spots) with similar connectivity across the different scenarios of climate change. Each keystone spot obtained by hierarchical classification was associated with one or more climate scenarios. One of these keystone spots was especially susceptible to the worst climate change scenario. Key riparian connectivity spots will be crucial for the management and restoration of highly threatened riparian systems and to ensure long-term biodiversity conservation.

Let Us Give Voice to Local Farmers: Preferences for Farm-Based Strategies to Enhance Human–Elephant Coexistence in Africa

Simple Summary

Local communities living on the edge of protected areas often experience negative impacts on their livelihoods due to wildlife. These situations threaten support for long-term conservation of wildlife and wild habitats so a key for conservation sustainability should be based on implementing socially accepted and economically sustainable mitigation practices. For successful design and implementation of mitigation strategies, it is vital to engage local communities and understand their preferences and previous experiences. In this study, we present a choice experiment as a tool to analyze local farmer preferences for the most common farm-based solutions to reduce African elephant crop damage. Results show that there are significant differences among responses triggered by farmers’ previous experience with elephants and socioeconomic situation, with a marked spatial distribution among respondents. This methodology, based on a choice modeling approach considering the differential availability of resources and previous experience with elephants or other wildlife, is highly applicable, with small changes in other areas where wildlife competes with local communities for resources. This approach also represents a suitable instrument for identifying stakeholders’ preferences in each specific context.

Abstract

Local communities surrounding wildlife corridors and natural reserves often face challenges related to human–wildlife coexistence. To mitigate the challenges and ensure the long-term conservation of wildlife, it is important to engage local communities in the design of conservation strategies. By conducting 480 face-to-face interviews in 30 villages along and adjacent to the Selous-Niassa Wildlife Corridor (Tanzania), we quantified farmers’ preferences for farm-based measures to mitigate African elephant damage using choice experiments. Results show that farmers considered no action the least preferred option, revealing that they are open to trying different measures. The most preferred management strategy matched with the preferences of wildlife rangers in the area, suggesting low concern about the potential conflicts between stakeholders. However, a latent class model suggests that there are significant differences among responses triggered by farmers’ previous experience with elephants, the intensity of the elephant damage, and the socioeconomic situation of the farmer. Results show a marked spatial distribution among respondents, highlighting the benefits of zone management as conflicts were found to be highly context dependent. Understanding the human dimension of conservation is essential for the successful planification and implementation of conservation strategies. Therefore, the development and broad utilization of methodologies to gather specific context information should be encouraged.

Impact of successive spring frosts on leaf phenology and radial growth in three deciduous tree species with contrasting climate requirements in central Spain

Rear-edge tree populations forming the equatorward limit of distribution of temperate species are assumed to be more adapted to climate variability than central (core) populations. However, climate is expected to become more variable and the frequency of climate extremes is forecasted to increase. Climatic extreme events such as heat waves, dry spells and spring frosts could become more frequent, and negatively impact and jeopardize rear-edge stands. To evaluate these ideas, we analyzed the growth response of trees to successive spring frosts in a mixed forest, where two temperate deciduous species, Fagus sylvatica L. (European beech) and Quercus petraea (Matt.) Liebl. (sessile oak), both at their southernmost edge, coexist with the Mediterranean Quercus pyrenaica Willd. (Pyrenean oak). Growth reductions in spring-frost years ranked across species as F. sylvatica > Q. petraea > Q. pyrenaica. Leaf flushing occurred earlier in F. sylvatica and later in Q. pyrenaica, suggesting that leaf phenology was a strong determinant of spring frost damage and stem growth reduction. The frost impact depended on prior climate conditions, since warmer days prior to frost occurrence predisposed to frost damage. Autumn Normalized Difference Vegetation Index data showed delayed leaf senescence in spring-frost years and subsequent years as compared with pre-frost years. In the studied forest, the negative impact of spring frosts on Q. petraea and especially on F. sylvatica growth, was considerably higher than the impacts due to drought. The succession of four spring frosts in the last two decades determined a trend of decreasing resistance of radial growth to frosts in F. sylvatica. The increased frequency of spring frosts might prevent the expansion and persistence of F. sylvatica in this rear-edge Mediterranean population.

Early life investment in antlers and body growth reflects adult performance in roe deer population under supplementary feeding conditions

Recent research has challenged the idea that cervid antlers are such costly traits, supporting the assertion early-life antler investment is an honest signal of adult phenotypic quality. However, inferences were made based on antler measurements while growing (velvet) and thus, studies on fully-formed clean antlers are needed to avoid possible bias caused by the inter-individual variation in antler growth phenology. We studied a semi-captive population of European roe deer inhabiting a sub-Mediterranean area (Valsemana research station) and living under optimal conditions (ad libitum food supply and veterinary care). Based on repeated measurements taken from 146 individuals, we assessed whether allocation to secondary sexual traits during early life affected body mass or antler development during adulthood. Furthermore, we evaluated which body measurements better predicted future male quality. Additionally, using 488 individuals, we described age-class-specific variation in male body measurements and assessed the decline in antler size between adult and senescent stages (i.e. magnitude of senescence). Results agree with the assertion that there is no negative effect of a high investment in antler during early life on adult antler size or body mass, but we suggest the use of clean antlers as a more robust and reliable measure. The variables that better predicted body mass during adulthood were yearling body mass and body size at 6 months. Antler score between 10 and 18 months resulted in the best indicator of adult antler size. Finally, we support the idea that the magnitude of senescence in antler size is smaller in environments with higher resource availability during winter.

P1010Association between left atrial fibrosis detected by cardiac magnetic resonance and endocardial electroanatomic mapping in the evaluation of the electrophysiological substrate in atrial fibrillation

Background

Atrial fibrillation (AF) is related to left atrial fibrosis, but its identification by late magnetic resonance imaging (LGE) with gadolinium (LGE) persists in controversy due to heterogeneous results in its correlation with the electroatomic map (EAM) and the difficulty of perform histological studies in humans.

Purpose

We try to examine the point-by-point association between high density EAM and LGE-MRI using an automatic and reproducible method.

Methods

A LGE-MRI was performed in 16 patients prior to ablation. Three different areas were established depending on the intensity of normalized enhancement for each patient according to their blood group with the image intensity ratio (IIR) (healthy <1.20, border area (BZ) ≥1.20 <1.32 and scar ≥1.32). The high density electroanatomic maps of the left atrium (LA) were projected onto the MRI, obtaining an automatic correlation point by point.

Results

The study obtained significant differences (p < 0.001) between voltage (mV) and CV (mm/ms) among healthy, BZ and scar areas, as well a significant inverse correlation (p < 0.001) between voltage and IIR (R=-0.39). It obtained too a significant correlation between CV and IIR (R=-0.24), but this showed a greater correlation in those patients who have the least dilated LA (p = 0.02).

Conclusions

LGE-MRI and EAM showed good correlation in delineating potential pathologic substrate in AF, but left atrium dilation could reduce the performance of the CMR in this task. Conduction velocity could be more sensitive than voltage and LGE-MRI to detect incipient substrate in AF.

Voltage and conduction velocity values Area /IIR Velocity (mm/ms) Voltage (mV) I / <.20 1.036(0.913-1.158) 1.593(1.489-1.696) 2 / ≥1.20 and <1.32 0.722(0.590-0.850) 0.792 (0.649-0,935) 3 / ≥1.32 0.623(0.473-0,733) 0.444(0.245-0.642) Voltage and conduction velocity values in the three areas of the LGE-RMN.

Abstract Figure. Correlation among voltage, VC and LA

Remote mapping of foodscapes using sUAS and a low cost BG-NIR sensor

The assessment of landscape condition for large herbivores, also known as foodscapes, is fast gaining interest in conservation and landscape management programs worldwide. Although traditional approaches are now being replaced by satellite imagery, several technical issues still need to be addressed before full standardization of remote sensing methods for these purposes. We present a low-cost method, based on the use of a modified blue/green/near-infrared (BG-NIR) camera housed on a small-Unmanned Aircraft System (sUAS), to create foodscapes for a generalist Mediterranean ungulate: the Iberian Ibex (Capra pyrenaica) in Northeast Spain. Faecal cuticle micro-histological analyses were used to assess the dietary preferences of ibexes and then individuals of the most common plant species (n = 19) were georeferenced to use as test samples. Because of the seasonal pattern in vegetation activity, based on the NDVI (Smooth term _Month = 21.5, p-value < .01, R² = 43%, from a GAM), images were recorded in winter and spring to represent contrasting vegetation phenology using two flight heights above ground level (30 and 60 m). Additionally, the range of image pixel sizes was 3.5-30 cm with the smallest pixel size representing the highest resolution. Boosted Trees were used to classify plant taxa based on spectral reflectance and create a foodscape of the study area. The number of target species, the sampling season, the height of flight and the image resolution were analysed to determine the accuracy of mapping the foodscape. The highest classification error (70.66%) was present when classifying all plant species using a 30 cm pixel size from acquisitions at 30 m height. The lowest error (18.7%), however, was present when predicting plants preferred by ibexes, at 3.5 cm pixel size acquired at 60 m height. This methodology can help to successfully monitor food availability and seasonality and to identify individual species.

Challenges on the conservation of traditional orchards: Tree damage as an indicator of sustainable grazing

Traditional orchard meadows are among the most valuable cultural and agricultural systems for nature conservation in Europe. They comprise scattered fruit trees over a highly diverse herbaceous layer and provide a wide range of ecosystem services. However, they are strongly endangered due to farmland intensification and abandonment. Livestock grazing is known to promote grassland diversity but it may also cause tree damage through debarking. In this study, we evaluated the effect of different grazers (cattle, horse and sheep) on fruit trees in 42 traditional orchards of the Rhenish uplands (Germany). Overall, we found that 70% of the study trees showed debarking damage, although most of them (40%) were slightly damaged (1-10% of the trunk debarked). Most debarked trees showed accumulated damage over time, and only 8% of the study trees were damaged during the last year. The probability of strong debarking (>50% of the trunk damaged) was higher in orchards grazed by cattle and horses than on those grazed by sheep (5.3 and 3.7-fold difference, respectively). Importantly, unsustainable levels of cumulative debarking caused a decay of crown development, which may strongly affect fruit production. Additionally, lower tree densities favored higher levels of debarking intensity but did not affect the probability of occurrence. Individual tree-protection was an effective practice in decreasing trunk debarking (95% reduction in tree damage occurrence). The impact of grazing animals on trees might represent a useful indicator to assess the sustainability of each grazing system and should be taken into account in future agriculture and conservation policies.

Unprecedented herbivory threatens rear-edge populations of Betula in southwestern Eurasia

Mediterranean rear-edge populations of Betula, located at the southwestern Eurasian margin of the distribution range, represent unique reservoirs of genetic diversity. However, increasing densities of wild ungulates, enhanced dryness, and wildfires threaten their future persistence. A historical perspective on the past responses of these relict populations to changing herbivory, fire occurrence and climatic conditions may contribute to assessing their future responses under comparable scenarios. We have reconstructed vegetation and disturbance (grazing, fire) history in the Cabañeros National Park (central-southern Spain) using the paleoecological records of two small mires. We particularly focused on the historical range of variation in disturbance regimes, and the dynamics of rear-edge Betula populations and herbivore densities. Changes in water availability, probably related to the North Atlantic Oscillation (NAO) index, and land-use history have played a crucial role in vegetation shifts. Our data suggest that heathlands (mainly Erica arborea and E. scoparia) and Quercus woodlands dominated during dry phases while Sphagnum bogs and Betula stands expanded during wet periods. Betula populations survived past moderately dry periods but were unable to cope with enhanced land use, particularly increasing livestock raising since ~1,100-900 cal. yr BP (850-1,050 CE), and eventually underwent local extinction. High herbivore densities not only contributed to the Betula demise but also caused the retreat of Sphagnum bogs. Ungulate densities further rose at ~200-100 cal. yr BP (1750-1850 CE) associated with the historically documented intensification of land use around the Ecclesiastical Confiscation. However, herbivory reached truly unprecedented values only during the last decades, following rural depopulation and subsequent promotion of big game hunting. For the first time in temperate and Mediterranean Europe, we have used the abundances of fossil dung fungal spores to assess quantitatively that current high herbivore densities exceed the historical range of variation. In contrast, present fire activity lies within the range of variation of the last millennia, with fires (mainly human-set) mostly occurring during dry periods. Our paleodata highlight the need of controlling the densities of wild ungulates to preserve ecosystem composition and functioning. We also urge to restore Betula populations in suitable habitats where they mostly disappeared because of excessive human activities.

Abstract OT2-07-06: Phase Ib study to assess the safety, tolerability, and clinical activity of gedatolisib in combination with palbociclib and either letrozole or fulvestrant in women with metastatic or locally advanced/recurrent breast cancer (B2151009)

Background:Hormone receptor positive (HR+) disease is the most common subset of advanced breast cancer (BC). The majority of women with HR+ metastatic BC (MBC) develop resistance to endocrine therapy (ET), with a median survival of 2-3 years. A new strategy to treat HR+ MBC involves the combination of ET and a cyclin-dependent kinase 4/6 inhibitor (CDKi 4/6), which has demonstrated improved progression-free survival (PFS) in both first-and later-line MBC. Preclinical evidence in PI3K-mutant cell-line xenografts demonstrated that combinations of PI3K and CDK4/6i reduced intrinsic and adaptive resistance to ET, leading to tumor regression (Vara, 2004; Pfizer data). Inhibition of the PI3K/mTOR pathway by gedatolisib (G) may provide a new therapy to overcome ET resistance. These findings support developing the triplet combination of G with the CDKi 4/6 palbociclib (P)+letrozole (L) or fulvestrant (F) for the treatment of patients (pts) with ER+/HER2- BC.

Methods: This ongoing study in women with ER+/HER2- MBC, in first- and later-line settings, includes a dose-escalation (DE) to evaluate dose-limiting toxicities (DLTs, primary endpoint [pEP]) and determine the maximum tolerated dose and recommended phase 2 dose (RP2D) for a triplet regimen of G+P+L or G+P+F. The escalation rules follow the modified toxicity probability interval method (G doses: 180 and 215 mg IV weekly). Treatment assignment to the triplet is based on investigator decision and bone-only disease is permitted. After RP2D determination for each triplet, a 3-arm expansion for early signs of efficacy (ESOE) will investigate objective response rate (ORR) compared to historical controls [pEP] of Arm A) G+P+L in first-line, B) G+P+F in pts with no prior CDKi 4/6 in second-line and C) G+P+F in pts who have received prior CDKi 4/6. Pts receive G+P (125 mg oral daily for 21 days [D] on and 7 D off) + L (2.5 mg oral daily) or F (500 mg IM on D1, 15 of cycle [C] 1; D1 of C2 and then 500 mg IM on D1 of all 28-D cycles). Secondary endpoints include safety, tumor response (DE), PFS (ESOE), pharmacokinetics (PK), and biomarker correlations associated with the PI3K/mTOR pathway.

Results: 27 pts received G (180 mg/week) in combination with P+L (L cohort, n=12) or P+F (F cohort, n=15). Median prior therapies were: L cohort: 1 (range: 0-4); F cohort: 2 (range 1-5). The 3 most common, drug-related adverse events (%) were in L cohort: nausea (75), neutropenia (67), and stomatitis (67); F cohort: stomatitis (67), nausea (60), and neutropenia (53). C1 DLTs were: L cohort: grade (gr) 3 neutropenia (n=1); F cohort: gr 3 stomatitis (n=1). Preliminary rates of stable disease/partial response were: L cohort: 33%/16%; F cohort: 40%/13%. PK parameters and next-generation sequencing of PI3K-related mutations are pending.

Conclusions: G can be combined with P+L or P+F with manageable toxicity and promising preliminary antitumor activity, even in heavily pretreated pts. Dose escalation, followed by expansion for ESOE, is ongoing.

This study is sponsored by Pfizer. Editorial support was provided by Engage Scientific Solutions and was funded by Pfizer.

Citation Format: Forero A, Han HS, Dees EC, Wesolowski R, Bardia A, Kabos P, Kern KA, Perea R, Pierce KJ, Houk B, Rugo HS. Phase Ib study to assess the safety, tolerability, and clinical activity of gedatolisib in combination with palbociclib and either letrozole or fulvestrant in women with metastatic or locally advanced/recurrent breast cancer (B2151009) [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr OT2-07-06.

Traditional cattle vs. introduced deer management in Chaco Serrano woodlands (Argentina): Analysis of environmental sustainability at increasing densities

Wild ungulate populations have increased and expanded considerably in many regions, including austral woodlands and forests where deer (Cervus elaphus) have been introduced as an alternative management to traditional cattle grazing. In this study, we compared traditional cattle with introduced deer management at increasing deer densities in the "Chaco Serrano" woodlands of Argentina to assess their ecological sustainability. We used three ecological indicators (abundance of tree regeneration, woody plant diversity and browsing damage) as proxies for environmental sustainability in woody systems. Our results indicate that traditional cattle management, at stocking rates of ∼10 ind km^-2, was the most ecologically sustainable management since it allowed greater tree regeneration abundance, higher richness of woody species and lower browsing damage. Importantly, cattle management and deer management at low densities (10 ind km^-2) showed no significant differences in species richness and abundance of seedlings, although deer caused greater browsing damage on saplings and juveniles. However, management regimes involving high deer densities (∼35 deer km²) was highly unsustainable in comparison to low (∼10 deer km^-2) and medium (∼20 deer km^-2) densities, with 40% probability of unsustainable browsing as opposed to less than 5% probability at low and medium densities. In addition, high deer densities caused a strong reduction in tree regeneration, with a 19-30% reduction in the abundance of seedlings and young trees when compared to low deer densities. These results showed that the effect of increasing deer densities on woody plant conservation was not linear, with high deer densities causing a disproportional deleterious effect on tree regeneration and sustainable browsing. Our results suggest that traditional management at low densities or the use of introduced ungulates (deer breeding areas) at low-medium densities (<20 deer km^-2) are compatible with woody vegetation conservation. However, further research is needed on plant palatability, animal habitat use (spatial heterogeneity) and species turnover and extinction (comparison to areas of low-null historical browsing) to better estimate environmental sustainability of Neotropical ungulate-dominated woodlands.

Dielectric relaxation in concentrated nonaqueous colloidal suspensions

In this work we report on the permittivity of suspensions of elongated goethite particles in silicone oils of different viscosities. In spite of the low conductivity of the systems, the electrode polarization is significant. To correct this phenomenon, the procedure chosen is the one called logarithmic derivative of the real part of the permittivity, and it proves to efficiently reduce the effect of electrodes to the extent that the spectra of pure liquids are flat in the accessible frequency range (20 Hz-1 MHz). In our suspensions, we observe the presence of a dielectric relaxation for frequencies in the range 4-40 kHz. In principle, such relaxations might be ascribed to the Maxwell-Wagner (MW) polarization. However, it is found that both the characteristic frequency and the relaxation amplitude of the suspensions increase with volume fraction, something unexpected for an MW relaxation. Such discrepancy can be explained by considering the Frenkel-Trukhan model, which reproduces the Maxwell-Wagner results in conditions of thin electrical double layers (which it is not our case). An excellent agreement is found between our data and the model predictions, using only the particle surface charge as a parameter.

Empty seeds are not always bad: simultaneous effect of seed emptiness and masting on animal seed predation

Seed masting and production of empty seeds have often been considered independently as different strategies to reduce seed predation by animals. Here, we integrate both phenomena within the whole assemblage of seed predators (both pre and post-dispersal) and in two contrasting microsites (open vs. sheltered) to improve our understanding of the factors controlling seed predation in a wind-dispersed tree (Ulmus laevis). In years with larger crop sizes more avian seed predators were attracted with an increase in the proportion of full seeds predated on the ground. However, for abundant crops, the presence of empty seeds decreased the proportion of full seeds predated. Empty seeds remained for a very long period in the tree, making location of full seeds more difficult for pre-dispersal predators and expanding the overall seed drop period at a very low cost (in dry biomass and allocation of C, N and P). Parthenocarpy (non-fertilized seeds) was the main cause of seed emptiness whereas seed abortion was produced in low quantity. These aborted seeds fell prematurely and, thus, could not work as deceptive seeds. A proportion of 50% empty seeds significantly reduced ground seed predation by 26%. However, a high rate of parthenocarpy (beyond 50% empty seeds) did not significantly reduce seed predation in comparison to 50% empty seeds. We also found a high variability and unpredictability in the production of empty seeds, both at tree and population level, making predator deception more effective. Open areas were especially important to facilitate seed survival since rodents (the main post-dispersal predators) consumed seeds mostly under shrub cover. In elm trees parthenocarpy is a common event that might work as an adaptive strategy to reduce seed predation. Masting per se did not apparently reduce the overall proportion of seeds predated in this wind-dispersed tree, but kept great numbers of seeds unconsumed.

Impact of colonoscopy screening on individuals at high risk of hereditary nonpolyposis colorectal cancer (HNPCC)

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Background: Colonoscopy screening reduces the incidence of, and mortality from, colorectal cancer (CRC) in individuals with HNPCC. The aim of this study was to determine the impact of colonoscopic follow-up in individuals at high risk of HNPCC, in terms of detection of precursor lesions (adenomas) or cancer.

Methods: Between 2005-2008, 163 individuals with HNPCC were advised to undergo regular follow-up colonoscopy. Compliance and results of the scans were evaluated annually and were verified with medical documentation.

Results: Of the 125 individuals who underwent at least one colonoscopy during the follow-up period of colonoscopy screening, in 33 subjects (26%) at least one colonic adenoma was detected. The median number of adenomas detected per colonoscopy in individuals with polyps was 2. The number of colonoscopies with polyps did not differ between women and men. However, the number of polyps removed by colonoscopy and the total number of polyps removed during the follow-up period was significantly higher in men (p = 0.005, p = 0.05 bilateral, respectively). 5 individuals (4%) were diagnosed with CRC, one of whom had two synchronous tumors. Of these, four individuals had properly followed the screening recommendations with the recommended frequency. In the case where two synchronous tumors were detected, it was the first colonoscopy screening that had been performed on the individual. None had had cancer previously, they were healthy relatives of an index case. All except one belonged to families that fulfilled the Amsterdam criteria I / II. All the tumors were diagnosed at an early stage, except two, which exhibited positive nodes.

Conclusions: Colonoscopy screening is effective in diagnosing colorectal adenomas and cancer in individuals with HNPCC. Men with HNPCC have a greater number of colorectal adenomas. Screening allows the detection of colorectal cancer at an early stages. Funded by a young researcher's grant from the Spanish Society of Medical Oncology 2006.

No significant financial relationships to disclose.

[Photopheresis: an alternative therapeutic approach in corticoresistant erosive oral lichen planus]

BACKGROUND

The immunomodulatory effect of extracorporeal photochemotherapy (photopheresis) coupled with its efficacy in lymphocytic skin diseases provides a rationale for its use for erosive lichen planus. We report two cases of chronic oral erosive and corticoresistant lichen planus successfully treated with photopheresis.

PATIENTS AND METHODS

Case 1. A 61-years-old man had erosive oral lichen planus for four years. Oral steroids were contra-indicated due to iatrogenic pancreatitis. After nine photopheresis sessions, subjective improvement occurred and the oral lesions were stabilized. Case 2. A 17-years-old woman presented corticodependent oral and genital erosive lichen planus and cutaneous lesions. After seven sessions of photopheresis, the patient was able to eat again and the pain decreased. After 20 sessions, the cutaneous lichen planus disappeared and complete remission of the mucous lesions was obtained without corticotherapy.

DISCUSSION

These two cases, together with 23 other cases reported elsewhere, strongly suggested the value of photopheresis in the treatment of erosive lichen planus. However, relapses after treatment withdrawal appear extremely frequent.

[Detection of Brucella melitensis by BACTEC 9050 system]

OBJECTIVES

To evaluate BACTEC 9050 system capacity for detection of bacteremia due to Brucella spp.

MATERIAL AND METHODS

16 febrile patients were studied during an epidemic infection for Brucella spp. Suspicious of brucellosis was serologically confirmed with Rose Bengal test and agglutination tube test. Only one blood culture was processed per patient. Ten millilitres of blood were inoculated in a Bactec Plus aerobic/F bottle and incubated in BACTEC 9050 automatic system. The bottles were kept in incubation during 21 days, and they were subcultured when the machine detected its growth; if not, a blind subculture was performed after 21 days.

RESULTS

13 of 16 patients showed bacteriemia (81.2%): 11 patients were detected by BACTEC 9050 system and 2 patients by blind subculture after 21 days. A positive result appeared in 149.8 hours (6.2 days) as a mean. Earlier detections were seen in 83 hours (3.4 days) and the latest ones at 245 hours (10.2 days). The aetiology agent of the epidemic infection was Brucella mellitensis biotype 1. We found significative differences comparing the BACTEC 9050 with BACTEC 9120/9240 systems (p<0.03).

CONCLUSIONS

Incubation protocols of 5 days are not useful for BACTEC 9050 system in the case brucellosis suspicious. Protocols of 7 would detect only 69.2% of the cases.

Scaling Behavior of the Rheological Properties of Montmorillonite Suspensions: Correlation between Interparticle Interaction and Degree of Flocculation

In this work we investigate some aspects of the rheological behavior of sodium montmorillonite (NaMt) suspensions in the pH range 3 to 9, of NaCl concentrations between 10(-3) and 10(-1) M, and of solid concentrations between 5 and 11% w/v. Three kinds of experiments were performed: steady-state viscometry, oscillatory test, and creep recovery. The physical quantities of interest were the yield stress sigma(y) of the suspensions, the elastic rigidity modulus G', and the instantaneous elastic compliance. Furthermore, G' was obtained from oscillatory tests in three different experiments: determination of the viscoelastic linear region, oscillograms, and the gelation process. All quantities were found to scale with the concentration of solids, C, according to a power law of the form Y=k(y)C(n). The exponents n were found to change from approximately 3 to approximately 6 when the pH was increased from 3 to 9 (at constant ionic strength 10(-2) M), although values as high as 10 were estimated when the NaCl concentration was reduced to 1 mM. Such values of n correlate well with the characteristics of the edge-to-face (E-F), edge-to-edge (E-E), and face-to-face (F-F) interparticle interactions. The minimum values of n correspond to maximum E-F attractions, whereas the largest n are associated with strong F-F repulsions. Copyright 2001 Academic Press.

[The epidemiology of Q fever in the northern area of Huelva, Spain]

OBJECTIVE

The aim of the present study is to know the prevalence, incidence and clinical presentation of the acute Q fever in the north of the Huelva district.

METHODOLOGY

a) Prevalence: 1,654 serum were randomly collected from the health district and distributed by their origin, age and sex. The methodology used was the indirect immunofluorescence, Coxiella burnetii phase II as antigen. Were regarded as positives those serum whose titles were equal or higher to 80; b) Incidence: prospective study of every case treated in hospital during 1996-1997 plus every referred patient from the different "Health Centers". An acute case of Q fever was established as a feverish syndrome of more than 2 days plus a title equal or higher to 320 against C. burnetti phase II antigen, and c) Clinical data: all the patients were clerked and similar form was filled up including the following items: pneumonia, hepatitis, headache, persistent fever, etc.

RESULTS

a) Prevalence: it was 5.08%, more frequent in men than in women; b) Incidence: 21 new cases over two years, an incidence of 12.70 cases per 100,000 population, and c)

CLINICAL PRESENTATION

feverish syndrome plus hepatitis in 100% of the cases, just two pneumonia were recorded and in 4 cases the clinical picture was associated to immunological symptoms with persistent fever.

CONCLUSION

A discrepancy between incidence and prevalence has been pointed out which makes us think that the majority of the Q fever cases in this area debut as a self restricted feverish syndrome which does not require specialized treatment.