Designing a survey to monitor multi-scale impacts of agri-environment schemes on mobile taxa.

Agri-environment schemes (AES) are key mechanisms to deliver conservation policy, and include management to provide resources for target taxa. Mobile species may move to areas where resources are increased, without this necessarily having an effect across the wider countryside or on populations over time. Most assessments of AES efficacy have been at small spatial scales, over short timescales, and shown varying results. We developed a survey design based on orthogonal gradients of AES management at local and landscape scales, which will enable the response of several taxa to be monitored. An evidence review of management effects on butterflies, birds and pollinating insects provided data to score AES options. Predicted gradients were calculated using AES uptake, weighted by the evidence scores. Predicted AES gradients for each taxon correlated strongly, and with the average gradient across taxa, supporting the co-location of surveys across different taxa. Nine 1 × 1 km survey squares were selected in each of four regional blocks with broadly homogenous background habitat characteristics. Squares in each block covered orthogonal contrasts across the range of AES gradients at local and landscape scales. This allows the effects of AES on species at each scale, and the interaction between scales, to be tested. AES options and broad habitats were mapped in field surveys, to verify predicted gradients which were based on AES option uptake data. The verified AES gradient had a strong positive relationship with the predicted gradient. AES gradients were broadly independent of background habitat within each block, likely allowing AES effects to be distinguished from potential effects of other habitat variables. Surveys of several mobile taxa are ongoing. This design will allow mobile taxa responses to AES to be tested in the surrounding countryside, as well as on land under AES management, and potentially in terms of population change over time. The design developed here provides a novel, pseudo-experimental approach for assessing the response of mobile species to gradients of management at two spatial scales. A similar design process could be applied in other regions that require a standardized approach to monitoring the impacts of management interventions on target taxa at landscape scales, if equivalent spatial data are available.

RISK-SENSITIVE ANTIPREDATOR BEHAVIOR IN THE TRINIDADIAN GUPPY, POECILIA RETICULATA.

The comparative approach has become a powerful tool for understanding how predation has shaped prey behavior. In this study we recorded the occurrence of common aquatic predator species and their densities in seven natural populations of Trinidadian guppies, Poecilia reticulata. We then exposed shoals of guppies from each of these populations to a series of predator treatments. Predator treatments differed in the species of predator used (pike cichlids, Crenicichla frenata; rivulus, Rivulus hartii; and freshwater prawns, Macrobrachium carcinus) and thus in the level of risk posed. We recorded the antipredator responses of guppies in each of these predator treatments. The strength of antipredator behavior shown by guppies was affected by both the type of predator they were exposed to and the level of predation risk they experienced naturally in the wild. Importantly, we found that guppies from high-risk populations showed a heightened response, compared to those from lower risk populations, only when exposed to the predator species that posed the greatest risk. Our results show the importance of individual predator species in shaping the behavioral traits of prey species at the population level. This has implications for prey movement between habitats that are geographically close but differ greatly in predator fauna.

Brain cytokine synthesis induced by an intraparenchymal injection of LPS is reduced in MCP-1-deficient mice prior to leucocyte recruitment.

We have previously shown that ischaemic lesions are smaller in monocyte chemoattractant protein-1-deficient (MCP-1(-/-)) mice than in wild-type (wt) controls. In addition to its role as a monocyte chemoattractant, monocyte chemoattractant protein-1 (MCP-1) has been proposed to contribute to lesion progression after focal ischaemia by driving local cytokine synthesis by resident glia. To investigate this hypothesis we injected lipopolysaccharide (LPS) into the brain parenchyma of MCP-1(-/-) mice and compared the resulting inflammatory response and production of proinflammatory cytokines to those in wt mice. Microglial and astrocyte morphological activation was the same in the two strains, but MCP-1(-/-) mice showed significantly lower levels of proinflammatory cytokine synthesis; interleukin-1beta (IL-1beta) and tumour necrosis factor-alpha (TNF-alpha) levels were up to 50% lower than in wt controls after 6 h. This reduced synthesis of proinflammatory cytokines occurred well before leucocyte recruitment to the central nervous system (CNS) is observed in this model of acute inflammation and thus cannot be attributed to lower numbers of recruited monocytes at the site of injury. We propose that MCP-1 contributes to acute CNS inflammation by pleiotropic mechanisms. In addition to being a potent chemoattractant for monocytes, we provide evidence here that MCP-1 can modify the responsiveness of CNS glia to acute inflammatory stimuli prior to leucocyte recruitment, thereby acting as a priming stimulus for cytokine synthesis in cells such as microglia.

The effects of different predator species on antipredator behavior in the Trinidadian guppy, Poecilia reticulata.

Different types of predators often elicit different antipredator responses in a common type of prey. Alternatively, some prey species may adopt a general response, which provides limited protection from many different types of predator. The Trinidadian guppy, Poecilia reticulata, is faced with a wide range of different predators throughout its range and is known to display varying levels of antipredator behavior depending on the predator assemblage. Pike cichlids, Crenicichla frenata, are regarded as the primary aquatic guppy predator in streams in the northern mountain range in Trinidad. As such, they are seen to be responsible for many of the differences in morphology, life history traits, and behavior between guppy populations from areas with few predators and those from areas with many pike cichlids. In this study we investigated how guppies responded when faced with different predator species using three common aquatic predators. We exposed shoals of ten guppies to one out of four treatments: no predator (control), pike cichlid, acara cichlid (Aequidens pulcher), and wolf fish (Hoplias malabaricus); and we made behavioral observations on both focal individuals and the shoal as a whole. Guppies showed significantly greater levels of predator inspection and shoaling behavior, foraged less, spent more time in the surface water, and stayed in significantly larger shoals when faced with pike cichlids than in other treatments. We discuss these results in the context of multiple predator effects.

Rapid method for the sensitive detection of protein contamination on surgical instruments.

Hospital sterile service departments (SSDs) currently rely on simple visual confirmation of cleanliness as an assessment of the efficacy of cleaning surgical instruments. The inherent inability to monitor low levels of infectious or proteinaceous contamination on surgical instruments creates the possibility that highly dangerous and robust biological agents may remain infectious and undetected even after standard cleaning and sterilization procedures have been employed. This paper describes the development of a novel microscopy technique, episcopic differential interference contrast microscope, combined with the fluorescent reagent, SYPRO Ruby, to rapidly detect brain tissue protein to below 400 pg/mm(2) on an instrument surface. This technique has displayed a minimum level of detection observed by 50% of volunteers of 85 pg/mm(2) (95% confidence intervals 67-112 pg/mm(2)). Quantitative assessment of instruments supplied from various SSDs enabled the establishment of a 'contamination index' of both proteinaceous and non-proteinaceous deposits on the surface. This new methodology for the assessment of surface contamination is generally applicable and should facilitate future quantitative surveys of instrument contamination in hospitals and other healthcare environments.

Assortative interactions and social networks in fish.

The mechanisms underpinning the structure of social networks in multiple fish populations were investigated. To our knowledge this is the first study to provide replication of social networks and therefore probably the first that allows general conclusions to be drawn. The social networks were all found to have a non-random structure and exhibited 'social cliquishness'. A number of factors were observed to contribute to this structuring. Firstly, social network structure was influenced by body length and shoaling tendency, with individuals interacting more frequently with conspecifics of similar body length and shoaling tendency. Secondly, individuals with many social contacts were found to interact with each other more often than with other conspecifics, a phenomenon known as a 'positive degree correlation'. Finally, repeated interactions between pairs of individuals occurred within the networks more often than expected by random interactions. The observed network structures will have ecological and evolutionary implications. For example, the occurrence of positive degree correlations suggests the possibility that pathogens and information (that are socially transmitted) could spread very fast within the populations. Furthermore, the occurrence of repeated interactions between pairs of individuals fulfils an important pre-requisite for the evolution of reciprocal altruism.

Focal lesions in the rat central nervous system induced by endothelin-1.

Axon injury following cerebral ischemia has received little scientific attention compared to the abundance of information dealing with the pathophysiology of grey matter ischemia. There are differences in the initial response of grey and white matter to ischemia in vitro. In this study we investigate whether the vasoactive peptide, endothelin-1, can generate a focal ischemic lesion in the white matter and compare the findings with endothelin-1-induced lesions in the grey matter. Using a minimally invasive technique to microinject endothelin-1 into selected brain regions, we observed an acute reduction in local MRI perfusion in the injected hemisphere after 1 hour. Twenty-four hours after microinjection of 10 pmoles of endothelin-1, we observed a loss of neurons in the grey matter. At 72 hours, neutrophils were absent and a macrophage/microglia response and astrocyte gliosis were detected. No breakdown in the blood-brain barrier was detected. After injection of 10 pmoles endothelin-1 into the cortical white matter, we observed prolific amyloid precursor protein-positive immunostaining (indicative of axonal disruption) and an increase in tau-1 immunostaining in oligodendrocytes at 6 hours. Similar to the grey matter lesions, no neutrophils were present, a macrophage/microglia response did not occur until 72 hours and there was no disruption in the blood-brain barrier. Focal injections of endothelin-1 into specific areas of the rat CNS represent a model to investigate therapeutic approaches to white matter ischemia.

Nramp1 modulates iron homoeostasis in vivo and in vitro: evidence for a role in cellular iron release involving de-acidification of intracellular vesicles.

Nramp1 controls responses to infection and encodes a biallelic (G169D) macrophage-restricted divalent-cation transporter. Nramp1(D169) is phenotypically null. We demonstrate Nramp1 is implicated in iron regulation in vivo. In spleen, expression is exclusive to Nramp1(G169) strains within the red pulp. By morphometric analysis, the distribution of splenic iron, following systemic overload, correlates with Nramp1 genotype. More iron is located within the red pulp in Nramp1(D169) strains, whereas in Nramp1(G169) strains iron deposits are localized within the marginal-zone metallophilic cells. Nramp1 immunoreactive protein is not present in control brain, but inducible within a hemorrhagic lesion model in Nramp1(G169) strains. Nramp1 protein expression demonstrates an inverse correlation to the presence of iron. Nramp1(G169) strains show no Perl's stain-reactive iron within the lesion. In contrast, Nramp1(D169) strains display iron-staining cells. The process of cellular iron regulation was investigated in vitro in Nramp1(G169) transfectant Raw264.7 macrophages. Greater (30-50%) iron efflux from Nramp1(G169) compared with Nramp1(D169) cells was determined. The extent of Nramp1-dependent iron-release was influenced by bafilomycin A1, and endogenous nitric oxide synthesis, both inhibitors of vacuolar-ATPase. This study demonstrates that Nramp1 regulates macrophage iron handling, and probably facilitates iron release from macrophages undergoing erythrophagocytosis in vivo.

Primary cardiac lymphoma.

A case of primary cardiac non-Hodgkin's B cell lymphoma is described in a patient presenting with obstructive right heart failure. Unlike the majority of cases, in this case the tumor was diagnosed ante mortem. THe patient's history combined with the aggressive use of noninvasive echocardiography are helpful in diagnosing this rare lesion.

The use of pericardium for the management of recurrent tracheoesophageal fistula.

Correction of congenital esophageal atresia and tracheoesophageal fistula (TEF) with either a primary or staged repair may result in recurrence of the TEF, most often at the site of esophageal anastomosis. Definitive operative repair of a recurrent TEF involves isolation and resection of the fistula with closure of the tracheal and esophageal defects. A technique is described, whereby mobilization of a vascularized pedicle of pericardium allows further enhancement of the standard repair of a recurrent TEF. The vascularized pedicle of pericardium serves to isolate the tracheal and esophageal suture lines from each other, as well as aid in sealing leaks at either or both suture lines. This may dramatically reduce the incidence of second recurrences and lower the overall operative mortality, reportedly as high as 59%.

Modern management of adult thoracic empyema.

Seventy adult patients with thoracic empyema were treated at the University of Michigan Medical Center between 1978 and 1982. Twenty-two (31%) of the empyemas were associated with pneumonia, 23 (33%) occurred as postoperative complications, and seven (10%) were iatrogenic. When used as the initial mode of drainage, repeat thoracentesis was successful in only four of 11 cases (36%). Similarly, closed tube thoracostomy, as initial treatment, was successful in only 14 of 40 cases (35%). Rib resection, however, provided cure or control in 10 of 11 patients (91%) when employed as the first treatment method. Eight of 12 patients (67%) with parapneumonic empyemas were treated successfully with closed tube thoracostomy, in contrast to only two of 17 patients (12%) with postoperative empyemas so treated. Eventual control or cure of empyema was achieved in 57 patients (81%), whereas 13 (19%) died (five from their empyema and eight with empyema as an active problem at the time of death). All of the five empyema-caused deaths occurred in patients who underwent chest tube drainage as the most invasive treatment modality. The mortality rate for immunosuppressed patients was 40% (four of 10 patients). This analysis of a large recent series of adult empyemas suggests that chest tube drainage is often inadequate and more aggressive management is likely to result in fewer treatment failures and fewer total procedures. Early rib resection, especially for postoperative empyemas and those in immunocompromised patients, is recommended.

Prevention of fatal hemorrhagic shock in dog by pretreatment with chronic high-salt diet.

The ability of a chronic high-salt diet to prevent fatal hemorrhagic shock was examined in 36 mongrel dogs. Twenty-one dogs received a dietary supplement of 9 g sodium chloride/day for 6 wk, and 15 dogs received the same basic diet for 6 wk but without the sodium chloride supplement. Hemorrhagic shock was induced in all dogs by bleeding into an overhanging sealed reservoir. After 3 h of shock, salt-pretreated dogs had a lower systemic vascular resistance of 0.70 +/- 0.02 versus 1.44 +/- 0.04 mmHg X ml-1 X min X kg (P less than 0.01) and a higher cardiac output of 53 +/- 3 versus 26 +/- 3 ml X min-1 X kg-1 (P less than 0.01) than was observed in controls. At 2.5 h of shock, the salt-pretreated dogs also experienced an increase in gastrointestinal (P less than 0.01), hepatic arterial, (P less than 0.05), kidney (P less than 0.05), brain (P less than 0.01), and heart blood flows (P less than 0.001) compared with 0.5 h of shock, whereas the control dogs experienced no increased flow during this same period. We also observed that after 3 h of hypotension there was a significantly smaller increase in plasma renin activity in the salt-pretreated dogs. Administration of 0.1 U X kg-1 X min-1 of hog renin eliminated the differences in systemic vascular resistance, cardiac output, and survival in five salt-pretreated dogs.

Dissociation between epicardial and transmural function during acute myocardial ischemia.

The relationship between epicardial and transmural function (measured with sonomicrometers) was examined in 13 anesthetized open-chest dogs. Systolic wall thickening was used as a standard of integrated transmural function to compare with epicardial function measured as segment shortening parallel to surface fibers. Three levels of coronary inflow restriction were produced by using decrements in systolic wall thickening as an index of changes in the transmural distribution of myocardial blood flow (microspheres) in myocardium perfused by the left anterior descending artery (anterior-apical group, n = 7) or circumflex artery (posterior-basal group, n = 6). Levels 1 and 2 were characterized by reductions in systolic wall thickening of 35% and 80%, respectively, and marked decreases in deep myocardial blood flow. In the subepicardium, myocardial blood flow was minimally affected at levels 1 and 2 and there was no change in posterior-basal epicardial segment shortening, but anterior segment shortening decreased significantly (by 21% and 37%, respectively). At level 3 myocardial blood flow was reduced transmurally, producing systolic wall thinning and marked epicardial dysfunction in both groups. Parallel epicardial segment shortening underestimated the extent of transmural dysfunction in both groups at levels 1 and 2 but the degree of underestimation was greatest in the posterior-basal group. Anterior-apical segment shortening was impaired at levels 1 and 2, whereas posterior-basal segment shortening was unaffected, suggesting that significant regional variability exists in the epicardial response to nontransmural ischemia.

Coronary vasodilator reserve in young dogs with moderate right ventricular hypertrophy.

The effects of experimental right ventricular (RV) pressure overload and RV hypertrophy on coronary vasodilator reserve in young animals is not well established. Therefore, we measured coronary vasodilator reserve in the right ventricle of dogs from 7 to 12 months old with moderate RV hypertrophy due to pulmonary artery banding performed 3 to 7 days after birth. In the 5 dogs with pulmonary artery banding, substantial RV hypertension developed (RV pressure at rest, 73 +/- 11 mm Hg) as did RV hypertrophy (ratio of RV free wall/left ventricular free wall weight, 1.86 +/- 0.41 gm/kg). The reactive hyperemic response following brief coronary occlusions was used as an index of coronary vasodilator reserve. The ratios of peak reactive hyperemic response to resting flow, however, were not significantly different in the 5 banded dogs compared with 7 control animals (3.6 +/- 1.0 versus 2.6 +/- 0.6); this implies that the extent of vasodilator reserve was similar with or without moderate RV hypertrophy. In addition, myocardial blood flow, as determined using radioactive microspheres, was not significantly different at rest: 0.57 +/- 0.09 ml/min per gram in the banded dogs versus 0.48 +/- 0.12 ml/min per gram in the controls. Uniform transmural distribution of blood flow was maintained during infusion of isoproterenol, which was used to increase myocardial oxygen requirements in both groups. Minimum coronary vascular resistance was significantly lower in the banded than the control dogs (1.5 +/- 0.6 versus 6.2 +/- 2.3; p less than 0.01). This difference suggests that the cross-sectional area of the right coronary vascular bed increased with the development of RV hypertrophy.

Norepinephrine plus phentolamine improves regional blood flow during experimental low cardiac output syndrome.

A complication of cardiac surgical procedures is postoperative low cardiac output syndrome. Treatment with norepinephrine plus phentolamine (N + P) is beneficial, but the effect of these agents on regional organ blood flow has not been evaluated. Therefore, in 6 dogs with long-term instrumentation, pentobarbital was infused to simulate low cardiac output (32 + 10% of the conscious control level). Infusions of N + P at 0.2, 0.5, and 1.0 microgram/kg/min restored cardiac pump performance to conscious control levels. Regional blood flows, determined with tracer-labeled microspheres, were substantially reduced in the low cardiac output state but increased to values not markedly different from control levels in all organs studied except stomach fundus during infusion of N + P. The pressure-work index, an indirect measure of myocardial oxygen consumption, did not increase to more than the conscious level except at the highest dose. The data demonstrate that simultaneous infusion of N and P is capable of successfully improving cardiac pump performance with restoration of vital organ perfusion and without evidence of excessive myocardial oxygen consumption.

Early experience with endoscopic percutaneous gastrostomy.

We performed endoscopic percutaneous gastrostomy (EPG) on 22 patients. All procedures were performed using local anesthesia with intravenous diazepam sedation. Formal laparotomy was not required. The mean patient age was 58 years (range, 21 to 83 years). Indications for EPG placement included neurologic disorders in 17 patients, head and neck tumors in four patients, and esophageal disease in one patient. The mean operative time for EPG was 27.5 minutes, with a range of 11 to 60 minutes. Two major complications, a gastrocolic fistula and an intraperitoneal gastric leak, occurred early in the series. The technique has been modified with no similar complications. Pneumoperitoneum after EPG was demonstrated in eight patients without sequelae. Ileus following EPG was not observed in any patient, and enteral feedings were uniformly resumed 48 hours after tube placement. Our early experience with EPG suggests that this technique is a safe, cost-effective, and time-saving alternative to traditional gastrostomy tube placement.