Evaluating consumptive and nonconsumptive predator effects on prey density using field time-series data.

Determining the degree to which predation affects prey abundance in natural communities constitutes a key goal of ecological research. Predators can affect prey through both consumptive effects (CEs) and nonconsumptive effects (NCEs), although the contributions of each mechanism to the density of prey populations remain largely hypothetical in most systems. Common statistical methods applied to time-series data cannot elucidate the mechanisms responsible for hypothesized predator effects on prey density (e.g., differentiate CEs from NCEs), nor can they provide parameters for predictive models. State-space models (SSMs) applied to time-series data offer a way to meet these goals. Here, we employ SSMs to assess effects of an invasive predatory zooplankter, Bythotrephes longimanus, on an important prey species, Daphnia mendotae, in Lake Michigan. We fit mechanistic models in an SSM framework to seasonal time series (1994-2012) using a recently developed, maximum-likelihood-based optimization method, iterated filtering, which can overcome challenges in ecological data (e.g., nonlinearities, measurement error, and irregular sampling intervals). Our results indicate that B. longimanus strongly influences D. mendotae dynamics, with mean annual peak densities of B. longimanus observed in Lake Michigan estimated to cause a 61% reduction in D. mendotae population growth rate and a 59% reduction in peak biomass density. Further, the observed B. longimanus effect is most consistent with an NCE via reduced birth rates. The SSM approach also provided estimates for key biological parameters (e.g., demographic rates) and the contribution of dynamic stochasticity and measurement error. Our study therefore provides evidence derived directly from survey data that the invasive zooplankter B. longimanus is affecting zooplankton demographics and offer parameter estimates needed to inform predictive models that explore the effect of B. longimanus under different scenarios, such as climate change.

Elevación sinusal con injerto de ramamandibular y colocación de implantes en una sola fase: a propósito de un caso / Sinus elevation with mandibular ramus graft and placement of implants in a single phase: regarding one case

Introducción: La pérdida de volumen óseo en sectores posteriores maxilares puede condicionar el tratamiento con implantes. Para ello se disponen de técnicas quirúrgicas regladas que permiten aumentar el hueso residual alveolar y permitir esta colocación de implantes. Existen numerosas zonas óseas donantes, como la rama mandibular. Cuando se dispone de altura ósea residual suficiente para garantizar la estabilidad de los implantes, estos se pueden colocar en la misma cirugía. Paciente y Método: Varón de 53 años remitido para la colocación de implantes en sector posterior maxilar derecho. Se le sometió a cirugía de elevación de seno maxilar con injerto de ramamandibular y material liofilizado, con colocación de implantes en una misma fase, y un seguimiento clínico a cuatro años en carga protésica Conclusiones: La técnica de elevación de seno maxilar con injerto de rama mandibular y colocación de implantes en una sola fase se trata de un procedimiento seguro con resultados predecibles cuando existe hueso residual suficiente para asegurar la estabilidad primaria de los implantes (AU)

Introduction: The loss of bone volume in posterior maxillary sectors can condition implant treatments. Therefore, regulated surgical techniques that permit increasing the residual alveolar bone and allow the placement of implants is available. There are numerous donor bone areas, such as the mandibular ramus. When sufficient residual bone height is available to guarantee the stability of the implants, they can be placed in the same surgery. Patient and Method: Male of 53 years of age referred for the placement of implants in right posterior maxillary sector. He was subjected to surgery to elevate the maxillary sinus with graft from mandibular ramus and lyophilised material, with placement of implants in the same phase, and clinical monitoring for four years in prosthetic load. Conclusions: The technique of maxillary sinus elevation with mandibular ramus graft and placement of implants in a single phase deals with a safe procedure with predictable results when there exists sufficient residual bone to ensure the primary stability of the implants (AU)

Efeito do laser terapeutico de baixa potencia sobre o processo de reparacao ossea em Tibia de Rato / Effect of low power therapeutic laser on process of bone healing in Rat Tibia

Este estudo teve por objetivo avaliar os efeitos do laser terapeutico de baixa potencia sobre o processo de reparacao ossea em tibia de rato. O modelom experimental consistiu na realizacao de uma osteotomia mecanica por escareacao na face medial da tibia de 48 ratos machos, utilizando uma broca odontologica de aco cilindrica. Os animais foram divididos em 3 grupos, sendo que os grupos 1 e 2 foram irradiados com laser na dose de 5 J/cm2 e 50 J/cm2, respectivamente, enquanto o grupo 3 (controle) recebeu tratamento, respectivamente. Os parametros referentes ao tecido de reparo avaliados foram: 1. comportamento biomecanico ao final de 14 dias PO e 2. morfologia ao final de 7 e 14 dias do PO, referentes ao tecido de reparo. Os chados das analises histomorfologicas dos 7 dias do PO demonstraram melhor evolucao do processo de reparacao no grupo irradiado com a dose de 50 J/cm2, comparado aos demais grupos. Esses resultados sugerem que, sob as condicoes xperiemntais da investigacao, terapia laser de baixa potencia (LLLT) favorece o processo de reparacao ossea durante seus estagios iniciais

A reliable bridge to cardiac transplantation: the TCI left ventricular assist device.

The Thermo Cardiosystems (TCI) HeartMate, a pneumatically driven, implantable left ventricular assist device, was designed for long-term support of the failing heart. Between February 1990 and August 1992, the HeartMate was implanted in 11 heart transplant candidates because of profound deterioration of left ventricular function. Patients had a mean cardiac index of 1.6 L.min-1 x m-2 and a mean pulmonary capillary wedge pressure of 33 mm Hg despite maximal pharmacologic support with at least three inotropic medications. In addition, 5 patients were being supported with an intraaortic balloon pump. Nine patients were bridged successfully to cardiac transplantation. The mean cardiac index after implantation of the left ventricular assist device was 3.2 L.min-1 x m-2. Support ranged from 2 to 143 days (mean duration, 60 days). One patient died early of low output secondary to right heart failure, and a second died of air embolism, which occurred intraoperatively. All surviving patients became fully ambulatory. There were no thromboembolic complications during a total of 658 patient-days of support on a regimen of only 80 mg of aspirin daily. The 9 bridged patients are currently alive 4 to 34 months after transplantation. The TCI HeartMate provides safe and effective hemodynamic support with low risk of complications and virtual freedom from thromboembolism on a regimen of minimal anticoagulation.

Neutrophil lipoxygenase metabolism and adhesive function following acute thermal injury.

Leukotrienes, especially leukotriene B4, are important modulators of various neutrophil functions including adherence and chemotaxis. In previous work, we demonstrated that neutrophil adherence to extracellular matrixes was diminished in the acute stages of burn injury. In this study, we demonstrated that neutrophil adhesion to human and bovine endothelium in the baseline state and after stimulation with leukotriene B4 is depressed markedly after burn injury. The defect in stimulated adherence to endothelium was not specific to leukotriene B4 because impaired adhesion was observed with n-formyl-methionyl-leucyl-phenylalanine and ionophore A23187 as well. Moreover, the adherence defect correlated with 95% and 81% decreases in the release of leukotriene B4 and 5-hydroxy-(6E,87,117,147)-eicosatetraenoic acid, respectively, from burn PMN treated with A23187. Burn neutrophils also released proportionately more byproducts of leukotriene B4 omega oxidation, particularly 20-COOH-leukotriene B4, than did control neutrophils. When examined 3 1/2 weeks after injury, abnormalities in neutrophil leukotriene B4 generation and the adherence of burn neutrophils had recovered to near normal values. To determine whether the decreased release of leukotriene B4 from burn neutrophils was due to increased degradation or diminished synthesis of leukotriene B4, we examined the degradation of exogenous tritiated leukotriene B4 as well as the production of leukotriene B4 from tritiated arachidonic acid in neutrophils. Burn neutrophils converted significantly greater quantities of tritiated leukotriene B4 to tritiated 20-COOH-leukotriene B4 and synthesized markedly less tritiated leukotriene B4 from tritiated arachidonic acid than did control neutrophils, suggesting that decreased leukotriene B4 release by burn neutrophils was the result of both enhanced degradation and decreased synthesis.(ABSTRACT TRUNCATED AT 250 WORDS)

Fibronectin binding and neutrophil aggregation in burn injury.

Fibronectin (Fn) plays an important role in the adhesive function of many cells including neutrophils (PMN). We examined the hypothesis that activated PMN develop binding sites for fibronectin which allows for the aggregation of contiguous PMN. Because PMN adhesive function is altered in acute burn injury, we also investigated the role of Fn in the aggregation of PMN from subjects with acute thermal injury. The chemotactic peptide, n-formylmethionyl leucyl phenylalanine, induced rapid binding of radioiodinated plasma Fn to PMN. Significant binding of Fn was detected as early as 30 sec poststimulus and maximal binding occurred at 5 min. Fn binding was only partially reversible and nonsaturable. The chemotactic peptide induced aggregation and binding of Fn to PMN with similar kinetics, concentration dependence, temperature, and cation requirements. In burn patients, PMN demonstrated a significant decrease in chemotactic peptide-induced aggregation which was associated with decreased binding of Fn. Alterations in the binding of Fn to PMN may be responsible, in part, for diminished aggregation responses of PMN in the early stages of thermal injury.

Structural and functional analysis of the human neutrophil 1-15 antigen, an Mr 65,000 to 70,000 activation-associated membrane proteinase.

Previous studies with the anti-neutrophil/antichymotrypsin mAb 1-15 have identified an activation-associated, chymotrypsin-like activity within the membrane fraction of isolated human neutrophils (PMN). In the present study, the molecular and biochemical characteristics of mAb 1-15 Ag/proteinase were determined. On casein/acrylamide sizing gels, PMN membrane preparations were found to contain an Mr 58,000 to 84,000 band of Ca2(+)-dependent proteinase activity. Reducing and nonreducing SDS-PAGE of mAb 1-15-affinity-purified membrane proteins demonstrated specific recovery of an enzymatically active Mr 65,000 to 70,000 chymotrypsin-like Ag. The presence of a distinct membrane serine esterase of isoelectric point 6.3/Mr 65,000 to 70,000 was confirmed in active site-labeling experiments with the serine proteinase inhibitor [3H]diisopropylfluorophosphate (DFP). Substrate-affinity chromatography with phe-Sepharose or FMLP-Sepharose provided partial purification of enzyme activity among Mr 65,000 to 70,000 FMLP- or phe-binding proteins. Enzyme inhibition was obtained by incubation with mAb 1-15, DFP, N-carbobenzoxyl-phe-chlormethyl ketone, or PMSF, but not tosyl-amide-phenylethylchlormethyl ketone, bestatin, aprotinin, or phosphoramidon. In HPLC analysis, [3H]DFP labeled proteinase was found to comigrate with one of three FMLP-affinity-labeled membrane peaks, but unlike the FMLP surface receptor the DFP-labeling membrane proteinase was not modified by endoglycosidase F. We conclude that the mAb 1-15 Ag, which appears to play a role in PMN activation, is a distinct, active, Mr 65,000 to 70,000 serine proteinase with affinity for substrate sites containing aromatic amino acids.

Neutrophil adhesion in the elderly: inhibitory effects of plasma from elderly patients.

Neutrophil (PMN) adherence is a critical component of host defense against infection. We questioned whether abnormalities of PMN adherence may be responsible, in part, for the increased susceptibility to infection in the elderly. We examined the adherence of 51Cr-labeled PMN from 18 elderly (65-95 years) and 18 younger subjects (18-40 years) to gelatin-coated plastic (gel) and bovine aortic endothelial monolayers (BAEC). There was no difference in unstimulated or baseline adherence of elderly or control PMN to either gel or BAEC substrates. N-Formyl-methionyleucylphenylalanine (FMLP), phorbol myristate acetate (PMA), and calcium ionophore A23187 (CI) significantly increased adherence of elderly PMN to gel and BAEC by 204 and 140% for FMLP, 271 and 263% for PMA, and 211 and 150% for CI, respectively. No differences were observed in the increment in stimulated adherence between young and elderly PMN. In contrast, in 5 of 18 subjects, incubation of elderly or young PMN with 10% elderly plasma resulted in greater than 25% inhibition in baseline adherence to BAEC compared to their sex-matched controls. The effect of elderly plasma was specific for BAEC and not seen with the gel substrate and was also demonstrated using human venous endothelium. When the adherence assay was repeated with varying ratios of elderly and young plasma, PMN adherence to BAEC correlated inversely with the proportion of elderly plasma in the assay. With greater than 70% elderly plasma, adherence was depressed below that observed in the absence of plasma. These data suggest the presence of a factor(s) in elderly plasma which may diminish adherence to endothelium. This factor(s) may be important in the increased risk of infection in a segment of the elderly population.

A further exploration of the use of physical restraints in hospitalized patients.

Four hundred twenty-one consecutive patients admitted to an acute general medical ward and two acute rehabilitation medical wards were studied to compare the characteristics and outcomes of physically restrained patients and unrestrained patients. Restraints were used in 35 (13%) of the general medical patients and in 49 (34%) of the rehabilitation patients. The restrained general medical patients had higher mortality and morbidity rates than their unrestrained counterparts. Restrained patients had a higher prevalence of a psychiatric diagnosis, and major tranquilizers were used more than in their unrestrained counterparts in both settings. The general medical patients tended to have more than one type of restraint at a time, whereas the rehabilitation patients were restrained for longer proportions of their hospital stay. Thirty-three percent of the restrained patients whom we were able to interview expressed negative perceptions about the presence of the physical restraints. Moreover, it was found that the presence of cognitive and physical impairments were highly predictive of restraint use in both populations.

Neutrophil adhesive dysfunction in thermal injury: the role of fibronectin.

We examined neutrophil substrate adherence in 19 subjects with burns involving 1%-83% of their body surface area. Within 24 h of injury, neutrophils from burn patients demonstrated a 50% reduction in adhesion to both gelatin and plastic substrates when stimulated with N-formyl-L-methionyl-L-leucyl-L-phenylalanine (FMLP), phorbol myristate acetate, and calcium ionophore A23187. Neutrophil substrate adherence examined as long as two weeks after burn injury remained abnormal. Neutrophils, from burn patients, stimulated with FMLP, phorbol myristate acetate, and calcium ionophore A23187 demonstrated a 51%, 37%, and 45% decrease, respectively, in release of immunoreactive fibronectin compared with control neutrophils. In neutrophils from burn patients there was a 31% reduction in total neutrophil-associated fibronectin compared with controls. The decrement in release and total cellular content of fibronectin in neutrophils from burn patients did not change when reexamined on day 7 after injury. The magnitude and time course of alterations in the cellular content and release of fibronectin correlate with adhesive dysfunction after burn injury.

Fibronectin is stored but not synthesized in mature human peripheral blood granulocytes.

To investigate whether peripheral blood granulocytes can synthesize the adhesive glycoprotein, fibronectin, we sought to demonstrate the presence of messenger RNA coding for fibronectin within mature circulating granulocytes. Polyadenylated-enriched RNA was isolated from human peripheral blood granulocytes, human skin fibroblasts (synthesize fibronectin) and HeLa cells (lack fibronectin) and probed with a cDNA clone coding for the cell attachment domain of fibronectin. Hybridization of a fibronectin cDNA fragment occurred with fibroblast RNA but did not occur with granulocyte RNA despite a 100 fold excess granulocyte RNA. Incubation of granulocytes with n-formyl methionyl leucyl phenylalanine, a chemotactic peptide known to augment the release of fibronectin from granulocytes, failed to induce detectable levels of mRNA for fibronectin in granulocytes. There was no difference in the quantity of fibronectin released from chemotactic peptide-stimulated granulocytes pre-incubated in the presence or absence of the protein synthesis inhibitor, cycloheximide, suggesting that fibronectin exists in a stored form in granulocytes. These data suggest that fibronectin in mature granulocytes is the product of synthesis during early myeloid maturation.

Monoclonal antibody characterization of a chymotrypsin-like molecule on neutrophil membrane associated with cellular activation.

Monoclonal antibody 1-15 (Ab 1-15), is a murine anti-human neutrophil (PMN) IgG1 that inhibits PMN effector responses to N-formyl-met-leu-phe (FMLP) and phorbol myristate acetate. In this study, the effects of Ab 1-15 on PMN membrane-related functions were characterized: Ab 1-15 inhibited PMN superoxide (O-2) response to FMLP by 60% (P less than 0.005) without effect on the onset or duration of O-2 production. This inhibition of O-2 response was associated with a significant inhibition of PMN chymotrypsin-like, but not trypsin-like, protease activity. Cell fractionation studies indicated the presence of an Ab 1-15 inhibitable, chymotryptic neutral protease activity in PMN membranes. In studies of Ab 1-15 effects on membrane-related second messenger pathways, Ab 1-15 augmented both FMLP- and isoproterenol-induced intracellular cAMP accumulation, whereas alpha-chymotrypsin decreased PMN cAMP response to these stimuli. Our data suggest that the function-inhibiting, anti-PMN monoclonal Ab 1-15 defines a PMN chymotryptic enzyme on the membrane surface that is involved in regulation of two membrane-related functions, O-2 generation and cAMP generation.

Fibronectin mediates chemotactic factor-stimulated neutrophil substrate adhesion.

Plasma fibronectin has been implicated as an important determinant of neutrophil adhesion to plastic surfaces. Using a monoclonal antifibronectin antibody, we examined the role of fibronectin (Fn) in chemotactic factor-mediated neutrophil attachment to various substrates. The chemotactic factor N-formyl-methionyl-leucyl-phenylalanine (FMLP) significantly enhanced neutrophil adherence to multiple substrates including gelatin, gelatin coated with Fc fragments of human IgG or Fn, plastic alone, plastic coated with Fc fragments, or purified plasma Fn. An IgM monoclonal antibody to plasma Fn significantly inhibited FMLP-stimulated neutrophil attachment to gelatin, gelatin-Fc, gelatin-Fn, plastic, plastic-Fc, and plastic-Fn substrates when compared with the parent line myeloma supernatant or an irrelevant IgM monoclonal antibody. No reduction in FMLP-stimulated adherence to the gelatin-plasma or plastic-plasma substrates occurred in the presence of antibody. Anti-Fn antibody reduced FMLP-stimulated adhesion only when present during the entire assay; incubation of cells or substrates alone with antibody, followed by removal of excess antibody before addition of stimulus incubation, failed to alter adherence. These data suggest that neutrophil-derived Fn may play a role in chemotactic factor-induced neutrophil adherence to both collagenous and noncollagenous substrates. Further support for the hypothesis was suggested by the demonstration of release of immunoreactive Fn into incubation media from FMLP-stimulated neutrophils.

Use of a needle valve variable resistor to improve invasive blood pressure monitoring.

Inaccurate measurements using in-line systems are partly due to the resonance frequency. A variable acoustic resistor designed to change the damping coefficient of these monitoring systems was evaluated under clinical conditions. The device improved pressure transmission characteristics in measurements on 12 of 13 patients. Use of the device and of the bedside step-impulse test for calibration should improve the reliability of in-line blood pressure monitoring.