Proximity to a high traffic road: glucocorticoid and life history consequences for nestling white-crowned sparrows.

Roads have been associated with decreased reproductive success and biodiversity in avian communities and increased physiological stress in adult birds. Alternatively, roads may also increase food availability and reduce predator pressure. Previous studies have focused on adult birds, but nestlings may also be susceptible to the detrimental impacts of roads. We examined the effects of proximity to a road on nestling glucocorticoid activity and growth in the mountain white-crowned sparrow (Zonotrichia leucophrys oriantha). Additionally, we examined several possible indirect factors that may influence nestling corticosterone (CORT) activity secretion in relation to roads. These indirect effects include parental CORT activity, nest-site characteristics, and parental provisioning. And finally, we assessed possible fitness consequences of roads through measures of fledging success. Nestlings near roads had increased CORT activity, elevated at both baseline and stress-induced levels. Surprisingly, these nestlings were also bigger. Generally, greater corticosterone activity is associated with reduced growth. However, the hypothalamic-pituitary-adrenal axis matures through the nestling period (as nestlings get larger, HPA-activation is greater). Although much of the variance in CORT responses was explained by body size, nestling CORT responses were higher close to roads after controlling for developmental differences. Indirect effects of roads may be mediated through paternal care. Nestling CORT responses were correlated with paternal CORT responses and paternal provisioning increased near roads. Hence, nestlings near roads may be larger due to increased paternal attentiveness. And finally, nest predation was higher for nests close to the road. Roads have apparent costs for white-crowned sparrow nestlings--increased predation, and apparent benefits--increased size. The elevation in CORT activity seems to reflect both increased size (benefit) and elevation due to road proximity (cost). Whether or not roads are good or bad for nestlings remains equivocal. However, it is clear that roads affect nestlings; how or if these effects influence adult survival or reproduction remains to be elucidated.

Towards a receptor for nocistatin?

Nocistatin is a peptide derived from the pronociceptin precursor, the source of nociceptin, the endogenous ligand for the nociceptin (NOP or ORL1). Despite nocistatin showing activity in a wide range of assays for nociception and other CNS activities, there is a dearth of information regarding the cellular actions of this peptide in the brain, and no receptor for nocistatin has been identified. In a study published in this issue of the British Journal of Pharmacology, Fantin and colleagues demonstrate that nocistatin inhibits 5-HT release from cortical synaptosomes in a concentration-dependent and Pertussis toxin-sensitive manner. The actions of nocistatin are independent of activity at NOP receptors. This study represents the first unambiguous demonstration of nocistatin agonist actions in brain and, taken together with previous work in the spinal cord, provides strong evidence that there is an as yet unidentified G protein-coupled receptor for nocistatin.

Differentiating osteomyelitis from bone infarction in sickle cell disease.

This brief review discusses one possible approach to evaluating the sickle cell patient with bone pain. The major differential diagnoses include osteomyelitis and bone infarction. Based on previous studies, we provide an approach to assessing and treating patients with the possible diagnosis of osteomyelitis. An algorithm has been provided, which emphasizes the importance of the initial history and physical examination. Specific radiographic studies are recommended to aid in making the initial assessment and to determine whether the patient has an infarct or osteomyelitis. Differentiating osteomyelitis from infarction in sickle cell patients remains a challenge for the pediatrician. This algorithm can be used as a guide for physicians who evaluate such patients in the acute care setting.

Using an artificial neural network to detect activations during ventricular fibrillation.

Ventricular fibrillation is a cardiac arrhythmia that can result in sudden death. Understanding and treatment of this disorder would be improved if patterns of electrical activation could be accurately identified and studied during fibrillation. A feedforward artificial neural network using backpropagation was trained with the Rule-Based Method and the Current Source Density Method to identify cardiac tissue activation during fibrillation. Another feedforward artificial neural network that used backpropagation was trained with data preprocessed by those methods and the Transmembrane Current Method. Staged training, a new method that uses different sets of training examples in different stages, was used to improve the ability of the artificial neural networks to detect activation. Both artificial neural networks were able to correctly classify more than 92% of new test examples. The performance of both artificial neural networks improved when staged training was used. Thus, artificial neural networks may beuseful for identifying activation during ventricular fibrillation.

Human bone morphogenetic protein allografting for reconstruction of femoral nonunion.

A composite inductive allograft consisting of an allogeneic, autolysed, antigen-free cortical bone carrier lyophilized with partially purified human bone morphogenetic protein was implanted in 30 consecutive femoral reconstructions that resulted from failure of fracture healing. There were 24 atrophic shortened femoral nonunions, four equal length femoral nonunions, and two femoral malunions. There were 10 men and 20 women with an average age of 47 years (range, 28-75 years). Allogeneic, autolysed antigen-free cortical bone was used as a structural alloimplant and as a delivery system for partially purified human bone morphogenetic protein. The composite implant of human bone morphogenetic protein/allogeneic, autolysed antigen-free cortical bone was used in conjunction with one-stage lengthening of the extremity, restoration of mechanical axis and rotational alignment. In 26 of 30 femurs, the human bone morphogenetic protein/allogeneic autolysed antigen-free cortical bone consisted of an allogeneic cortical bone implant incorporated into a one-stage lengthening of atrophic femoral nonunion. In four patients with equal length femoral nonunions, the human bone morphogenetic protein/allogeneic, autolysed antigen-free implant was placed as an medical femoral shaft onlay graft. Internal remodeling of the implant occurred within 8 to 12 weeks after implantation. Lengthening defects greater than 2 cm were supplemented with intercalary autogeneic bone graft. Twenty-four femurs healed at an average of 6 months at an average followup of 55 months. Four of six plate fatigue failures were salvaged with repeat plating. Two patients were lost to followup. The human bone morphogenetic protein/allogeneic, autolysed antigen-free bone allograft is an excellent structural and delivery system that induces host bone formation and implant remodeling allowing salvage of difficult femoral nonunions.

The effect of inducing ventricular fibrillation with 50-Hz pacing versus T wave stimulation on the ability to defibrillate.

When testing an ICD, there are at least two techniques for inducing ventricular fibrillation: (1) high frequency (approximately equal to 50 Hz) pacing; and (2) a single T wave stimulus. It is generally assumed that these two methods yield similar results. This study directly tested this assumption. In six dogs, one defibrillation electrode was placed in the right ventricular (RV) apex and the second was placed cutaneously on the left thorax. All defibrillation and T wave stimuli were biphasic between these two electrodes. Pacing was monophasic from the tip of the RV catheter to the cutaneous patch. The voltage which defibrillates 50% of the time (DF50) was measured using a 10-step Bayesian up-down method. Observations for two DF50 measurements were randomly interleaved. For one DF50 measurement, fibrillation was induced with 99 pacing stimuli at a 20-ms pacing interval (50-Hz pacing). For the second DF50 measurement, fibrillation was induced with a single defibrillation shock of approximately 1/2 J delivered at a time corresponding to the peak of the T wave in the lead II electrogram (T wave stimuli). The average DF50 when measured after fibrillation induced with 50-Hz pacing was 379 +/- 54.6 V, as compared to 382 +/- 50.3 V when fibrillation was induced with T wave stimuli. The difference of 3 V was not statistically significant. If these results are confirmed in humans, it is reasonable to assume that the efficacy of a defibrillation shock is the same whether T wave stimuli or 50-Hz pacing are used to induce fibrillation.

One-stage lengthening of femoral nonunion augmented with human bone morphogenetic protein.

Fifteen patients with posttraumatic shortened atrophic femoral nonunions were treated with one-stage lengthening. The alloimplant was composed of allogeneic antigen extracted autolyzed human bone perfused with partially purified human cortical bone morphogenetic protein associated with noncollagenous protein and used as graft. The composite was lyophilized and sterilized with ethylene oxide. All 15 nonunions were atrophic diaphyseal and were lengthened through intercalary segmental defects bridged with the human bone morphogenetic protein composite alloimplants stabilized to the medial femoral cortex through plate osteosynthesis and lag screw fixation. One lengthened proximal femur had fatigue failure of the plate and was treated successfully by exchange plating. The average increase in length was 2.8 cm (range, 1.5-5 cm) and an average percentage increase in length of 8% (range, 4%-132%) of the residual shortened femur. The human bone morphogenetic protein composite produced an immediate reactive bone formation in the host bone and progressive remodeling of the donor recipient interfaces. There were no infections, allergic reactions, clinical rejection of the human bone morphogenetic protein composite alloimplants, or evidence of malignant disease. One-stage femoral lengthening augmented with human bone morphogenetic protein composite graft bridged the intercalary defect, remodeled the atrophic host bone and restored bone continuity within 1 to 2 years. Human bone morphogenetic protein composite alloimplants are a substitute of autogeneic bone graft and offer an alternative to iliac crest bone without the associated morbidity.

The Lie/Bet Questionnaire for screening pathological gamblers: a follow-up study.

This study follows up one in which was derived a two-item screening questionnaire for pathological gambling. In the previous study, the two-item screening questionnaire had sensitivity of .99 and specificity of .91. In this study, testing 295 men (116 pathological gamblers and 179 controls) and 128 women (30 pathological gamblers and 98 controls), sensitivity was 1.00 and specificity .85. In the previous study, the predictive value of a positive result was .92 and of a negative result .99. In this sample, the predictive value of a positive result was .78 and of a negative result 1.00. These results indicate the two questions represent a useful screening device for a DSM-IV diagnosis of pathological gambling.

Spatial organization, predictability, and determinism in ventricular fibrillation.

The degree of spatial organization of ventricular fibrillation (VF) is a fundamental dynamical property of the arrhythmia and may determine the success of proposed therapeutic approaches. Spatial organization is closely related to the dimension of VF, and hence to its predictability and controllability. We have explored several techniques to quantify spatial organization during VF, to predict patterns of activity, and to see how spatial organization and predictability change as the arrhythmia progresses. Epicardial electrograms recorded from pig hearts using rectangular arrays of unipolar extracellular electrodes (1 mm spacing) were analyzed. The correlation length of VF, the number of Karhunen-Loeve modes required to approximate data during VF, the number, size and recurrence of wavefronts, and the mean square error of epicardial potential fields predicted 0.256 seconds into the future were all estimated. The ability of regularly-timed pacing stimuli to capture areas of fibrillating myocardium during VF was confirmed by a significant increase in local spatial organization. Results indicate that VF is neither "low-dimensional chaos" (dimension <5) nor "random" behavior (dimension= infinity ), but is a high-dimensional response with a degree of spatial coherence that changes as the arrhythmia progresses. (c) 1998 American Institute of Physics.

Influence of health status and the timing of surgery on mortality in hip fracture patients.

The purpose of the study was to determine the relationship of preoperative health status and time to surgery to mortality and late functional outcome in hip fracture patients. The records of 168 consecutive patients who had operations for 171 intertrochanteric or femoral neck fractures were reviewed retrospectively. Preoperative health status was assessed by the American Society of Anesthetists (ASA) classification. Postoperative outcome was determined by mortality and ambulatory status. The follow-up period for survivors averaged 33 months. The overall mortality was 14% at 1 year, which rose to 26% at 2 years, and 33% at 3 years. The 3-year mortality was significantly less for ASA I and II patients (23%) than for ASA III, IV, and V patients (39%). There was also a significant difference in mortality between patients having surgery within 24 hours of admission (20%) and those having surgery beyond 24 hours of admission (50%). Even when only the healthy subgroup of ASA I and II patients were considered, the relative risk of death was 4.5 times greater if surgery occurred after 24 hours from admission. These data support the concept that hip fracture patients are not a homogeneous group with respect to mortality and that the ASA classification is a good predictor of mortality. Patients who had surgery within 24 hours of admission had a significantly lower mortality rate than did patients having surgery beyond 24 hours of admission, regardless of their preoperative ASA classification.

The aqueous pore through the translocon has a diameter of 40-60 A during cotranslational protein translocation at the ER membrane.

Eukaryotic secretory proteins are cotranslationally translocated through the endoplasmic reticulum (ER) membrane via aqueous pores that span the lipid bilayer. Fluorescent probes were incorporated into nascent secretory proteins using modified Lys-tRNAs, and the resulting nascent chains were sealed off from the cytosol in fully assembled translocation intermediates. Fluorescence quenching agents of different sizes were then introduced into the ER lumen in order to determine which were small enough to enter the pore and to quench the fluorescence of probes inside the ribosome and/or the pore. These accessibility studies showed that the aqueous pore in a functioning translocon is 40-60 A in diameter, making it the largest hole observed to date in a membrane that must maintain a permeability barrier.

Internal atrial defibrillation in humans. Improved efficacy of biphasic waveforms and the importance of phase duration.

BACKGROUND: The optimal waveform for internal atrial defibrillation (IAD) in humans is unknown. This study tested the effect of waveform duration and phase duration on the efficacy of biphasic waveforms for IAD. METHODS AND RESULTS: Electrodes were positioned in the right atrial appendage and coronary sinus in 13 patients. In part 1, the atrial defibrillation thresholds (ADFTs) for 5 monophasic waveforms (2, 4, 6, 10, and 20 ms) and 5 symmetrical biphasic waveforms (1/1, 2/2, 3/3, 5/5, and 10/10 ms) were compared in 6 patients. In part 2, the ADFTs for two asymmetrical biphasic waveforms (7.5/2.5 and 2.5/7.5 ms) were compared with those for a symmetrical biphasic waveform (5/5 ms) and a monophasic waveform (10 ms) in 7 patients. In part 1, biphasics with total durations of 4 to 20 ms had significantly lower ADFTs than monophasic waveforms of the same total duration. For a total duration of 2 ms, there was no significant difference in ADFTs between the biphasic and the monophasic waveforms. There was no difference between symmetrical biphasic waveforms of 4 to 20 ms. In part 2, the 7.5/2.5 ms asymmetrical biphasic had significantly lower ADFTs than the three other waveforms tested. Both the 7.5/2.5 ms asymmetrical and the 5/5 ms symmetrical biphasic waveform had significantly lower ADFTs than the 2.5/7.5 ms asymmetrical biphasic and the 10 ms monophasic waveforms. CONCLUSIONS: For IAD in humans, biphasic waveforms were more efficacious than monophasic waveforms. This improved efficacy is related to the total duration of the biphasic waveform and each individual phase duration of the biphasic waveform.

The Lie/Bet Questionnaire for screening pathological gamblers.

A 2-item questionnaire was derived from 10 DSM-IV criteria for pathological gambling. Subjects were 362 men, 191 classified as pathological gamblers and 171 as nonproblem-gambling controls. The two items were significant in sensitivity and negative predictive value and significant in specificity and positive predictive value.

Internal cardioversion in two patients with atrial fibrillation refractory to external cardioversion.

A 26-year-old man underwent an electrophysiological study for evaluation of a history of congenital heart disease, presyncope, and wide complex tachycardia. During the study the patient developed sustained atrial fibrillation with a rapid ventricular response. A 17-year-old man with a history of sick sinus syndrome developed sustained atrial fibrillation. Both patients failed four attempts at external cardioversion with a maximum delivered energy of 360 J. Low energy cardioversion was successful in both patients using biphasic waveforms and internal transvenous defibrillation electrodes. Internal cardioversion using a transvenous electrode system can be successful in patients with atrial fibrillation refractory to external cardioversion.

Pectoralis major tendon avulsion in association with a proximal humerus fracture.

We report a very rare case of an avulsion of the pectoralis major tendon in association with a two-part proximal humerus fracture. Pectoralis major tendon avulsion was confirmed intraoperatively during open reduction and internal fixation of the humerus fracture. In retrospect, the preoperative radiographic finding of posterolateral and proximal displacement of the humeral shaft suggested an injury to the pectoralis major. Because others have reported that the best treatment of a pectoralis major tendon avulsion is surgical repair, we feel that it is important to suspect such an injury in a proximal humerus fracture when this anatomic displacement is present.

Predicting patterns of epicardial potentials during ventricular fibrillation.

Ventricular fibrillation (VF) is a fatal cardiac arrhythmia, characterized by uncoordinated propagation of activation wavefronts in the ventricular myocardium. Short-term predictions of epicardial potential fields during VF in pigs were attempted using linear techniques, and prediction accuracy was measured at various stages during sustained episodes. VF was induced in five pigs via premature electrical stimulation. Unipolar electrograms were recorded from an epicardial array of 506 electrodes in a 22 x 23 array with 1-mm spacing. Optimal spatial basis functions (modes) and time-varying weighting coefficients were found using the Karhunen-Loeve decomposition. Linear autoregressive (AR) models incorporating the dynamics of only a few spatial modes led to predicted patterns that were qualitatively similar to observed patterns. Predictions were made 0.256 s into the future, based on 0.768 s of past data, over an area of approximately 5 cm2 on the ventricular epicardium. The mean squared error of predictions varied from as much as 1.23 to as little as 0.14, normalized to the variance of the actual data. Inconsistency in long-term forcasts is partly due to the limitations of linear AR models. Changes in predictability, however, were consistent. Predictability varied inversely with spatial complexity, as measured by the mean squared error of a five-mode approximation. Predictability also increased significantly during the first minute of VF.