Impact of patch age and size on forest soil characteristics in European agricultural landscapes

Many landscapes worldwide are characterized by the presence of a mosaic of forest patches with contrasting age and size embedded in a matrix of agricultural land. However, our understanding of the effects of these key forest patch features on the soil nutrient status (in terms of nitrogen, carbon, and phosphorus) and soil pH is still limited due to a lack of large-scale data. To address this research gap, we analyzed 830 soil samples from nearly 200 forest patches varying in age (recent versus ancient forests) and size (small versus larger patches) along a 2500-km latitudinal gradient across Europe. We also considered environmental covariates at multiple scales to increase the generality of our research, including variation in macroclimate, nitrogen deposition rates, forest cover in a buffer zone, basal area and soil type. Multiple linear mixed-effects models were performed to test the combined effects of patch features and environmental covariates on soil nutrients and pH. Recent patches had higher total soil phosphorus concentrations and stocks in the mineral soil layer, along with a lower nitrogen to phosphorus ratio within that layer. Small patches generally had a higher mineral soil pH. Mineral soil nitrogen stocks were lower in forest patches with older age and larger size, as a result of a significant interactive effect. Additionally, environmental covariates had significant effects on soil nutrients, including carbon, nitrogen, phosphorus, and their stoichiometry, depending on the specific covariates. In some cases, the effect of patch age on mineral soil phosphorus stocks was greater than that of environmental covariates. Our findings underpin the important roles of forest patch age and size for the forest soil nutrient status. Long-term studies assessing edge effects and soil development in post-agricultural forests are needed, especially in a context of changing land use and climate.

Maladaptive plastic responses of flowering time to geothermal heating

Phenotypic plasticity might increase fitness if the conditions under which it evolved remain unaltered, but becomes maladaptive if the environment no longer provides reliable cues for subsequent conditions. In seasonal environments, timing of reproduction can respond plastically to spring temperature, maximizing the benefits of a long season while minimizing the exposure to unfavorable cold temperatures. However, if the relationship between early spring temperatures and later conditions changes, the optimal response might change. In geothermally heated ecosystems, the plastic response of flowering time to springtime soil temperature that has evolved in unheated areas is likely to be non-optimal, because soil temperatures are higher and decoupled from air temperatures in heated areas. We therefore expect natural selection to favor a lower plasticity and a delayed flowering in these areas. Using observational data along a natural geothermal warming gradient, we tested the hypothesis that selection on flowering time depends on soil temperature and favors later flowering on warmer soils in the perennial Cerastium fontanum. In both study years, plants growing in warmer soils began flowering earlier than plants growing in colder soils, suggesting that first flowering date (FFD) responds plastically to soil temperature. In one of the two study years, selection favored earlier flowering in colder soils but later flowering in warmer soils, suggesting that the current level of plastic advance of FFD on warmer soils may be maladaptive in some years. Our results illustrate the advantages of using natural experiments, such as geothermal ecosystems, to examine selection in environments that recently have undergone major changes. Such knowledge is essential to understand and predict both ecological and evolutionary responses to climate warming.

Spring temperature drives phenotypic selection on plasticity of flowering time

In seasonal environments, a high responsiveness of development to increasing temperatures in spring can infer benefits in terms of a longer growing season, but also costs in terms of an increased risk of facing unfavourable weather conditions. Still, we know little about how climatic conditions influence the optimal plastic response. Using 22 years of field observations for the perennial forest herb Lathyrus vernus, we assessed phenotypic selection on among-individual variation in reaction norms of flowering time to spring temperature, and examined if among-year variation in selection on plasticity was associated with spring temperature conditions. We found significant among-individual variation in mean flowering time and flowering time plasticity, and that plants that flowered earlier also had a more plastic flowering time. Selection favoured individuals with an earlier mean flowering time and a lower thermal plasticity of flowering time. Less plastic individuals were more strongly favoured in colder springs, indicating that spring temperature influenced optimal flowering time plasticity. Our results show how selection on plasticity can be linked to climatic conditions, and illustrate how we can understand and predict evolutionary responses of organisms to changing environmental conditions.

Selection against early flowering in geothermally heated soils is associated with pollen but not prey availability in a carnivorous plant

PREMISE

In high-latitude environments, plastic responses of phenology to increasing spring temperatures allow plants to extend growing seasons while avoiding late frosts. However, evolved plasticity might become maladaptive if climatic conditions change and spring temperatures no longer provide reliable cues for conditions important for fitness. Maladaptative phenological responses might be related to both abiotic factors and mismatches with interacting species. When mismatches arise, we expect selection to favor changes in phenology.

METHODS

We combined observations along a soil temperature gradient in a geothermally heated area with pollen and prey supplementation experiments and examined how phenotypic selection on flowering time in the carnivorous plant Pinguicula vulgaris depends on soil temperature, and pollen and prey availability.

RESULTS

Flowering advanced and fitness decreased with increasing soil temperature. However, in pollen-supplemented plants, fitness instead increased with soil temperature. In heated soils, there was selection favoring later flowering, while earlier flowering was favored in unheated soils. This pattern remained also after artificially increasing pollen and prey availability.

CONCLUSIONS

Plant-pollinator mismatches can be an important reason why evolved plastic responses of flowering time to increasing spring temperatures become maladaptive under novel environmental conditions, and why there is selection to delay flowering. In our study, selection for later flowering remained after artificially increasing pollen availability, suggesting that abiotic factors also contribute to the observed selection. Identifying the factors that make evolved phenological responses maladaptive under novel conditions is fundamental for understanding and predicting evolutionary responses to climate warming.

Multimodal analgesia for treatment of allodynia and hyperalgesia after major trauma in a cat

Case summary

A 2-year-old polytraumatized male cat was admitted to a teaching hospital for correction of a defective inguinal herniorrhaphy. Upon arrival, the cat showed signs of neuropathic pain, including allodynia and hyperalgesia. Analgesic therapy was initiated with methadone and metamizole; however, 24 h later, the signs of pain continued. Reparative surgery was performed, and a multimodal analgesic regimen was administered (methadone, ketamine, wound catheter and epidural anesthesia). Postoperatively, the cat showed signs of severe pain, assessed using the UNESP-Botucatu multidimensional composite pain scale. Rescue analgesia was initiated, which included methadone, bupivacaine (subcutaneous wound-diffusion catheter) and transversus abdominis plane block. Because the response was incomplete, co-adjuvant therapy (pregabalin and electroacupuncture) was then implemented. Fourteen days after admission, the patient was discharged with oral tramadol and pregabalin for at-home treatment.

Relevance and novel information

Neuropathic pain is caused by a primary lesion or dysfunction in the nervous system and is a well-described complication following trauma, surgical procedures such as hernia repair, and inadequate analgesia. The aims of this report are to: (1) describe a presentation of neuropathic pain to highlight the recognition of clinical signs such as allodynia and hyperalgesia in cats; and (2) describe treatment of multi-origin, severe, long-standing, ‘mixed’ pain (acute inflammatory with a neuropathic component). The patient was managed using multiple analgesic strategies (multimodal analgesia), including opioids, non-steroidal anti-inflammatory drugs, locoregional anesthesia, co-adjuvant drugs and non-pharmacological therapy (electroacupuncture).

A natural heating experiment: Phenotypic and genotypic responses of plant phenology to geothermal soil warming

Under global warming, the survival of many populations of sedentary organisms in seasonal environments will largely depend on their ability to cope with warming in situ by means of phenotypic plasticity or adaptive evolution. This is particularly true in high-latitude environments, where current growing seasons are short, and expected temperature increases large. In such short-growing season environments, the timing of growth and reproduction is critical to survival. Here, we use the unique setting provided by a natural geothermal soil warming gradient (Hengill geothermal area, Iceland) to study the response of Cerastium fontanum flowering phenology to temperature. We hypothesized that trait expression and phenotypic selection on flowering phenology are related to soil temperature, and tested the hypothesis that temperature-driven differences in selection on phenology have resulted in genetic differentiation using a common garden experiment. In the field, phenology was related to soil temperature, with plants in warmer microsites flowering earlier than plants at colder microsites. In the common garden, plants responded to spring warming in a counter-gradient fashion; plants originating from warmer microsites flowered relatively later than those originating from colder microsites. A likely explanation for this pattern is that plants from colder microsites have been selected to compensate for the shorter growing season by starting development at lower temperatures. However, in our study we did not find evidence of variation in phenotypic selection on phenology in relation to temperature, but selection consistently favoured early flowering. Our results show that soil temperature influences trait expression and suggest the existence of genetically based variation in flowering phenology leading to counter-gradient local adaptation along a gradient of soil temperatures. An important implication of our results is that observed phenotypic responses of phenology to global warming might often be a combination of short-term plastic responses and long-term evolutionary responses, acting in different directions.

Resource overlap and dilution effects shape host plant use in a myrmecophilous butterfly

The effects of consumers on fitness of resource organisms are a complex function of the spatio-temporal distribution of the resources, consumer functional responses and trait preferences, and availability of other resources. The ubiquitous variation in the intensity of species interactions has important consequences for the ecological and evolutionary dynamics of natural populations. Nevertheless, little is known about the processes causing this variation and their operational scales. Here, we examine how variation in the intensity of a consumer-resource interaction is related to resource timing, resource density and abundance of other resources. Using the butterfly consumer Phengaris alcon and its two sequential resources, the host plant Gentiana pneumonanthe and the host ants Myrmica spp., we investigated how butterfly egg-laying depended on focal host plant phenology, density and phenology of neighbouring host plants and host ant abundance. Butterflies preferred plants that simultaneously maximized the availability of both larval resources in time and space, that is, they chose early-flowering plants that were of higher nutritional quality for larvae where host ants were abundant. Both the probability of oviposition and the number of eggs were lower in plant individuals with a high neighbour density than in more isolated plants, and this dilution effect was stronger when neighbours flowered early. Our results show that plant-herbivore interactions simultaneously depend on the spatio-temporal distribution of a focal resource and on the small-scale spatial variation in the abundance of other herbivore resources. Given that consumers have negative effects on fitness and prefer certain timing of the resource organisms, this implies that processes acting at the levels of individuals, populations and communities simultaneously contribute to variation in consumer-mediated natural selection.

Caterpillar seed predators mediate shifts in selection on flowering phenology in their host plant

Variation in selection among populations and years has important implications for evolutionary trajectories of populations. Yet, the agents of selection causing this variation have rarely been identified. Selection on the time of reproduction within a season in plants might differ both among populations and among years, and selection can be mediated by both mutualists and antagonists. We investigated if differences in the direction of phenotypic selection on flowering phenology among 20 populations of Gentiana pneumonanthe during 2 yr were related to the presence of the butterfly seed predator Phengaris alcon, and if butterfly incidence was associated with the abundance of the butterfly's second host, Myrmica ants. In plant populations without the butterfly, phenotypic selection favored earlier flowering. In populations where the butterfly was present, caterpillars preferentially attacked early-flowering individuals, shifting the direction of selection to favoring later flowering. Butterfly incidence in plant populations increased with ant abundance. Our results demonstrate that antagonistic interactions can shift the direction of selection on flowering phenology, and suggest that such shifts might be associated with differences in the community context.

Promoting biodiversity values of small forest patches in agricultural landscapes: Ecological drivers and social demand

Small forest patches embedded in agricultural (and peri-urban) landscapes in Western Europe play a key role for biodiversity conservation with a recognized capacity of delivering a wide suite of ecosystem services. Measures aimed to preserve these patches should be both socially desirable and ecologically effective. This study presents a joint ecologic and economic assessment conducted on small forest patches in Flanders (Belgium) and Picardie (N France). In each study region, two contrasted types of agricultural landscapes were selected. Open field (OF) and Bocage (B) landscapes are distinguished by the intensity of their usage and higher connectivity in the B landscapes. The social demand for enhancing biodiversity and forest structure diversity as well as for increasing the forest area at the expenses of agricultural land is estimated through an economic valuation survey. These results are compared with the outcomes of an ecological survey where the influence of structural features of the forest patches on the associated herbaceous diversity is assessed. The ecological and economic surveys show contrasting results; increasing tree species richness is ecologically more important for herbaceous diversity in the patch, but both tree species richness and herbaceous diversity obtain insignificant willingness to pay estimates. Furthermore, although respondents prefer the proposed changes to take place in the region where they live, we find out that social preferences and ecological effectiveness do differ between landscapes that represent different intensities of land use. Dwellers where the landscape is perceived as more "degraded" attach more value to diversity enhancement, suggesting a prioritization of initiatives in these area. In contrast, the ecological analyses show that prioritizing the protection and enhancement of the relatively better-off areas is more ecologically effective. Our study calls for a balance between ecological effectiveness and welfare benefits, suggesting that cost effectiveness studies should consider these approaches jointly.

Habitat properties are key drivers of Borrelia burgdorferi (s.l.) prevalence in Ixodes ricinus populations of deciduous forest fragments

BACKGROUND

The tick Ixodes ricinus has considerable impact on the health of humans and other terrestrial animals because it transmits several tick-borne pathogens (TBPs) such as B. burgdorferi (sensu lato), which causes Lyme borreliosis (LB). Small forest patches of agricultural landscapes provide many ecosystem services and also the disservice of LB risk. Biotic interactions and environmental filtering shape tick host communities distinctively between specific regions of Europe, which makes evaluating the dilution effect hypothesis and its influence across various scales challenging. Latitude, macroclimate, landscape and habitat properties drive both hosts and ticks and are comparable metrics across Europe. Therefore, we instead assess these environmental drivers as indicators and determine their respective roles for the prevalence of B. burgdorferi in I. ricinus.

METHODS

We sampled I. ricinus and measured environmental properties of macroclimate, landscape and habitat quality of forest patches in agricultural landscapes along a European macroclimatic gradient. We used linear mixed models to determine significant drivers and their relative importance for nymphal and adult B. burgdorferi prevalence. We suggest a new prevalence index, which is pool-size independent.

RESULTS

During summer months, our prevalence index varied between 0 and 0.4 per forest patch, indicating a low to moderate disservice. Habitat properties exerted a fourfold larger influence on B. burgdorferi prevalence than macroclimate and landscape properties combined. Increasingly available ecotone habitat of focal forest patches diluted and edge density at landscape scale amplified B. burgdorferi prevalence. Indicators of habitat attractiveness for tick hosts (food resources and shelter) were the most important predictors within habitat patches. More diverse and abundant macro- and microhabitat had a diluting effect, as it presumably diversifies the niches for tick-hosts and decreases the probability of contact between ticks and their hosts and hence the transmission likelihood.

CONCLUSIONS

Diluting effects of more diverse habitat patches would pose another reason to maintain or restore high biodiversity in forest patches of rural landscapes. We suggest classifying habitat patches by their regulating services as dilution and amplification habitat, which predominantly either decrease or increase B. burgdorferi prevalence at local and landscape scale and hence LB risk. Particular emphasis on promoting LB-diluting properties should be put on the management of those habitats that are frequently used by humans. In the light of these findings, climate change may be of little concern for LB risk at local scales, but this should be evaluated further.

Environmental drivers of Ixodes ricinus abundance in forest fragments of rural European landscapes

BACKGROUND

The castor bean tick (Ixodes ricinus) transmits infectious diseases such as Lyme borreliosis, which constitutes an important ecosystem disservice. Despite many local studies, a comprehensive understanding of the key drivers of tick abundance at the continental scale is still lacking. We analyze a large set of environmental factors as potential drivers of I. ricinus abundance. Our multi-scale study was carried out in deciduous forest fragments dispersed within two contrasting rural landscapes of eight regions, along a macroclimatic gradient stretching from southern France to central Sweden and Estonia. We surveyed the abundance of I. ricinus, plant community composition, forest structure and soil properties and compiled data on landscape structure, macroclimate and habitat properties. We used linear mixed models to analyze patterns and derived the relative importance of the significant drivers.

RESULTS

Many drivers had, on their own, either a moderate or small explanatory value for the abundance of I. ricinus, but combined they explained a substantial part of variation. This emphasizes the complex ecology of I. ricinus and the relevance of environmental factors for tick abundance. Macroclimate only explained a small fraction of variation, while properties of macro- and microhabitat, which buffer macroclimate, had a considerable impact on tick abundance. The amount of forest and the composition of the surrounding rural landscape were additionally important drivers of tick abundance. Functional (dispersules) and structural (density of tree and shrub layers) properties of the habitat patch played an important role. Various diversity metrics had only a small relative importance. Ontogenetic tick stages showed pronounced differences in their response. The abundance of nymphs and adults is explained by the preceding stage with a positive relationship, indicating a cumulative effect of drivers.

CONCLUSIONS

Our findings suggest that the ecosystem disservices of tick-borne diseases, via the abundance of ticks, strongly depends on habitat properties and thus on how humans manage ecosystems from the scale of the microhabitat to the landscape. This study stresses the need to further evaluate the interaction between climate change and ecosystem management on I. ricinus abundance.

The effect of exposure to nanoparticles and nanomaterials on the mammalian epigenome

Human exposure to nanomaterials and nanoparticles is increasing rapidly, but their effects on human health are still largely unknown. Epigenetic modifications are attracting ever more interest as possible underlying molecular mechanisms of gene–environment interactions, highlighting them as potential molecular targets following exposure to nanomaterials and nanoparticles. Interestingly, recent research has identified changes in DNA methylation, histone post-translational modifications, and noncoding RNAs in mammalian cells exposed to nanomaterials and nanoparticles. However, the challenge for the future will be to determine the molecular pathways driving these epigenetic alterations, the possible functional consequences, and the potential effects on health.

Pressurized liquid extraction of Neochloris oleoabundans for the recovery of bioactive carotenoids with anti-proliferative activity against human colon cancer cells

In recent years, the green microalgae Neochloris oleoabundans have demonstrated to be an interesting natural source of carotenoids that could be used as potential food additive. In this work, different N. oleoabundans extracts obtained by pressurized liquid extraction (PLE) have been analyzed in depth to evaluate the influence of different culture conditions (effect of nitrogen, light intensity or carbon supplied) not only on the total carotenoid content but also on the carotenoid composition produced by these microalgae. Regardless of the cultivation conditions, lutein and carotenoid monoesters were the most abundant carotenoids representing more than 60% of the total content in all extracts. Afterwards, the effect of the different N. oleoabundans extracts and the dose-effect of the most potent algae extracts (namely, N9, PS and CO₂ (-)) on the proliferation of human colon cancer cells lines (HT-29 and SW480) and a cell line established from a primary colon cancer cell culture (HGUE-C-1) were evaluated by an MTT assay whereas a stepwise multiple regression analysis was performed to get additional evidences on the relationship between carotenoid content and the antiproliferative activity. Results revealed that, as a general trend, those extracts with high total carotenoid content showed comparably antiproliferative activity being possible to establish a high correlation between the cell proliferation values and the carotenoid constituents. Monoesters showed the highest contribution to cell proliferation inhibition whereas lutein and violaxanthin showed negative correlation and diesters and zeaxanthin showed a positive significant contribution to cell proliferation.

Use of herbs, spices and their bioactive compounds in active food packaging

Natural additives obtained from herbs and spices are being increasingly used in the food packaging industry.

[Presence of Bartonella henselae in cats: natural reservoir quantification and human exposition risk of this zoonoses in Chile]

BACKGROUND

The availability of a serologic test for cat scratch disease in humans has allowed the diagnosis of an increasing number of cases of this disease in Chile.

AIM

To perform a serological survey for Bartonella henselae among cats in Chile.

MATERIAL AND METHODS

Blood samples from 187 cats living in three Chilean cities were obtained. IgG antibodies against Bartonella henselae were measured using indirect immunofluorescence. Blood cultures were done in 60 samples. The presence of Bartonella henselae in positive cultures was confirmed by restriction fragment length polymorphism polymerase chain reaction (RFLP-PCR).

RESULTS

The general prevalence of IgG antibodies against Bartonella henselae was 85.6%. No differences in this prevalence were found among cats younger or older than 1 year, or those infested or not infested with fleas. However domestic cats had a lower prevalence when compared with stray cats (73 and 90% respectively, p <0.01). Bartonella henselae was isolated in 41% of blood cultures. All the isolated were confirmed as Bartonella henselae by RFLP-PCR.

CONCLUSIONS

This study found an important reservoir of Bartonella henselae in Chilean cats and therefore a high risk of exposure in humans who have contact with them.

Amygdala kindling differentially regulates the expression of the elements involved in TRH transmission

Subthreshold electrical stimulation of the amygdala (kindling) activates neuronal pathways increasing the expression of several neuropeptides including thyrotropin releasing-hormone (TRH). Partial kindling enhances TRH expression and the activity or its inactivating ectoenzyme; once kindling is established (stage V), TRH and its mRNA levels are further increased but TRH-binding and pyroglutamyl aminopeptidase II (PPII) activity decreased in epileptogenic areas. To determine whether variations in TRH receptor binding or PPII activity are due to regulation of their synthesis, mRNA levels of TRH receptors (R1, R2) and PPII were semi-quantified by RT-PCR in amygdala, frontal cortex and hippocampus of kindled rats sacrificed at stage II or V. Increased mRNA levels of PPII were found at stage II in amygdala and frontal cortex, and of pro-TRH and TRH-R2, in amygdala and hippocampus. At stage V, pro-TRH mRNA levels increased and those of PPII, decreased in the three regions; TRH-R2 mRNA levels diminished in amygdala and frontal cortex and of TRH-R1 only in amygdala. In situ hybridization analyses revealed, at stage II, enhanced TRH-R1 mRNA levels in dentate gyrus and amygdala while decreased in piriform cortex; those of TRH-R2 increased in amygdala, CA2, dentate gyrus, piriform cortex, thalamus and subiculum and of PPII, in CAs and piriform cortex. In contrast, at stage V decreased expression of TRH-R1 occurred in amygdala, CA2/3, dentate gyrus and piriform cortex; of TRH-R2 in CA2, thalamus and piriform cortex, and of PPII in CA2, and amygdala. The magnitude of changes differed between ipsi and contralateral side. These results support a trans-synaptic modulation of all elements involved in TRH transmission in conditions that stimulate the activity of TRHergic neurons. They show that reported changes in PPII activity or TRH-binding caused by kindling relate to regulation of the expression of TRH receptors and degrading enzyme.

Coadministration of tacrolimus and ketoconazole in renal transplant recipients: cost analysis and review of metabolic effects

BACKGROUND

The high cost of tacrolimus is a major problem in Mexico. Ketoconazole increases tacrolimus bioavailability by inhibiting cytochrome P450 3A4 and glycoprotein-p.

OBJECTIVE

To demonstrate that the coadministration of tacrolimus and ketoconazole allows a significant dose and cost reduction.

PATIENTS AND METHODS

This prospective study administered tacrolimus and ketoconazole to renal transplant recipients with dose adjustment according to tacrolimus blood levels. At 0-1, 1-6, 6-12, and 12-24 months posttransplant demographic, transplant type, immunosuppression, and clinical data were reviewed. The cost of tacrolimus treatment was calculated based on the dose used as compared to the recommended dose (0.15-0.20 mg/kg/d).

RESULTS

Eleven patients with an age of 40 years (range, 13-71) were studied from May 2000 to August 2002. Follow-up was 15 +/- 10 months. Graft source was living donor in six patients and cadaveric in five. All patients received tacrolimus + mycophenolate mofetil + prednisone. The mean ketoconazole dose was 87 mg/d. Since the dose of tacrolimus was 0.04 mg/kg/d versus the recommended dose of 0.15-0.20 mg/kg/d, there was a 78% cost reduction (P =.000). Tacrolimus blood levels remained in the therapeutic range. There were no drug-related side effects.

CONCLUSIONS

The co-administration of tacrolimus and ketoconazole results in a substantial dose and cost reduction while maintaining therapeutic levels. No adverse metabolic consequences were seen with this combination.

[Study of hepatitis B virus replication and infection by other hepatitis viruses in patients with chronic hepatitis B virus infection]

AIM

To study hepatitis B virus (HBV) replication in a series of patients with HBV infection and to analyze the frequency of associated hepatitis C virus (HCV) and hepatitis D (HDV) infection.

PATIENTS AND METHOD

Serological markers of HBV, HCV and HDV, transaminase values and HBV DNA were studied in serum samples from 463 patients with chronic HBV infection.

RESULTS

Three hundred ninety-six (85.5%) were classified as hepatitis B, 33 (7.1%) as hepatitis B and C, 17 (3.6%) as hepatitis B and D and 17 (3.6%) as hepatitis B, C and D. Sixty-seven percent of patients with hepatitis B and 33% of those with chronic hepatitis B were asymptomatic HBsAg carriers. HVB DNA was identified in 27.7% of patients with hepatitis B, in 24% of those with hepatitis B and C, in 11.7% of those with hepatitis B and D and in 29.4% of those with hepatitis B, C and D. HBV DNA and elevated transaminase levels were found in 63% of HBeAg-positive patients and in only 16% of those who were anti-HBe-positive. These latter were considered candidates for antiviral treatment.

CONCLUSIONS

In our environment, most patients with HBV infection are asymptomatic HBsAg carriers. Viral replication and elevated alanine aminotransferase levels were found in 22% of the patients. Consequently, these patients are candidates for antiviral treatment. Between 3.6% and 7.1% of patients with hepatitis B presented coinfection with HCV or HDV, or both. No significant differences were found in HBV replication among the different groups.

Survival evaluation of treatment modality in squamous cell carcinoma of the oral cavity and oropharynx

The treatment of squamous cell carcinoma of the mouth and oropharynx continues to change. In this primary report, we compared the results obtained by combined surgery and radiation therapy, or either modality alone. Other methods such as brachytherapy, or hyperfractionated radiotherapy, were not included in our protocols. A statistical analysis of the 3- and 5-year survival rates in relation to location and size of the primary tumour, stage at initial presentation, treatment modality and recurrence, was carried out in 88 patients with squamous cell carcinoma of the oral cavity or oropharynx. The overall survival rate was 73.8% at 3 years and 66.3% at 5 years. Size of tumour and stage at presentation were significant when P value was adjusted by site. Survival was significantly associated with type of treatment (combined approach obtained superior results), location of primary tumour, and recurrence. The type of neck dissection did not show any effect. Therapeutic modality used, stage, and location of primary tumour significantly influenced survival. A more selective combined initial treatment according to site and stage (distribution) is recommended.

Effects of a toxin from the mucus of the Caribbean sea anemone (Bunodosoma granulifera) on the ionic currents of single ventricular mammalian cardiomyocytes

The effects were studied of a toxin (Bainh) isolated from the secretion of the Caribbean sea anemone Bunodosoma granulifera on electrical and mechanical activities of rat ventricular muscle. The effects on the ionic currents of single rat and dog ventricular cardiomyocytes were studied using the whole-cell recording patch-clamp technique. In the concentration range from 1 to 10 mg/ml, Bainh increased the force of contraction and induced an increase in action potential duration of ventricular multicellular preparations. In single cardiomyocytes, at concentrations up to 10 mg/ml Bainh showed no significant effects on the sodium current. However, at 0.5-1 mg/ml it increased the L-type Ca current (ICaL) by 25-50%. This increase in ICaL was not voltage dependent and was reversible after washout. The transient outward current was not significantly affected by Bainh (1-10 mg/ml). In this concentration range, Bainh markedly (approximately 75%) increased the inward-going rectifier current, IKI. This effect that was not voltage dependent and was fully reversible upon returning to control solution. It is suggested that these effects on ionic currents could explain the positive inotropic action of Bainh on cardiac multicellular preparations.

[Potter syndrome caused by bilateral renal agenesis and duodenal atresia]

A case of Potter syndrome secondary to renal agenesia and duodenal atresia with anular pancreas is presented. The karyotype was 47 XY-21. We discuss the antenatal diagnosis and the perinatal management.

[Gastric emptying of fluids and gallbladder contraction in non-ulcer dyspepsia]

Non-ulcer dyspepsia is a frequent clinical entity characterized by chronic upper gastrointestinal symptoms without organic lesions by radiology, sonography or endoscopy. We studied simultaneously the rate of gastric emptying and gallbladder contraction in 10 patients with non-ulcer dyspepsia and in 10 healthy controls after ingestion of 500 cc of isotonic saline, and 500 cc of a liquid mixed meal, hypercaloric and hyperosmotic. The measurements were done by direct real-time ultrasonic imaging in fasting and were repeated at regular intervals (15-30 minutes) after the liquid meal, until complete gastric emptying was established. We found with the liquid mixed meal, the patients with non-ulcer dyspepsia had a significant delay in gastric emptying and gallbladder hypokinesis with faulty contraction and slow refilling. Dynamic ultrasonographic studies are useful in patients with non-ulcer dyspepsia.

[Antibodies against hepatitis C virus. Experience with a second generation test]

A second generation recombinant immunoblot assay to detect antibodies against Hepatitis C virus (RIBA II, Ortho Diagnostic Systems) was applied to 30 serum samples repeatedly reactive to ELISA anti-HCV c100-3, 11 from hemodialysis patients, 11 from patients with chronic hepatitis and 8 from patients with cirrhosis. The assay detects individual antibodies directed to 4 antigenic components of the C virus, 2 antigens, c100 and 5-1-1 contained in the original ELISA assay and 2 new antigens, c33c and c22-3 the latter structural in nature. From the total of 30 samples, 23 (77%) were reactive, 4 (13%) indeterminate and 3 (10%) non reactive to the RIBA II assay. Much variation was observed regarding the response to each individual antigen. c22-3 was the most frequently reactive with the highest intensity. RIBA II assay confirmed a high percentage of the reactive results with the ELISA c-100-3, serum samples that were non reactive to RIBA showed a low optical density with ELISA. c22-3 was the most sensitive antigenic component.

[Antibodies against hepatitis C virus in patients with liver diseases and in risk subjects. Preliminary report]

The recent discovery of an antigenic component of the causative agent of Non-A, Non-B hepatitis, has led to the characterization of this virus--Hepatitis C Virus (HCV)--and to the identification of an antibody present in infected subjects (anti-HCV) detected by means of the C-100 antigen derived from a nonstructural region of the viral genome. Using a commercial Kit (Ortho Diagnostic Inc.), the incidence of anti-HCV antibody was studied in the Military Hospital "Dr. Carlos Arvelo" of Caracas, Venezuela with the following results: Health personnel (doctors, nurses, laboratory staff): 102 persons studied, 2 positives (1.96%); 16 patients in chronic hemodialysis: 6 positives (33%); 20 subjects with antibodies against HIV virus, confirmed by Western Blot: 7 positives (35.4%). Of 10 patients with Surface Antigen negative Chronic Hepatitis, 7 (70%) positive for anti-HCV, of 25 patients with cirrhosis: 12 positive (48%), 2 patients with hepatocarcinoma 1 positive (50%). There was also a high incidence of total anti-core antibodies in the patients studied. The results suggest that the hepatitis C virus could be playing an important role as a causative factor of liver diseases in our Country.