Retention of stress susceptibility in the mdx mouse model of Duchenne muscular dystrophy after PGC-1α overexpression or ablation of IDO1 or CD38

Duchenne muscular dystrophy (DMD) is a lethal degenerative muscle wasting disease caused by the loss of the structural protein dystrophin with secondary pathological manifestations including metabolic dysfunction, mood and behavioral disorders. In the mildly affected mdx mouse model of DMD, brief scruff stress causes inactivity, while more severe subordination stress results in lethality. Here, we investigated the kynurenine pathway of tryptophan degradation and the nicotinamide adenine dinucleotide (NAD+) metabolic pathway in mdx mice and their involvement as possible mediators of mdx stress-related pathology. We identified downregulation of the kynurenic acid shunt, a neuroprotective branch of the kynurenine pathway, in mdx skeletal muscle associated with attenuated peroxisome proliferator-activated receptor-gamma coactivator 1 alpha (PGC-1α) transcriptional regulatory activity. Restoring the kynurenic acid shunt by skeletal muscle-specific PGC-1α overexpression in mdx mice did not prevent scruff -induced inactivity, nor did abrogating extrahepatic kynurenine pathway activity by genetic deletion of the pathway rate-limiting enzyme, indoleamine oxygenase 1. We further show that reduced NAD+ production in mdx skeletal muscle after subordination stress exposure corresponded with elevated levels of NAD+ catabolites produced by ectoenzyme cluster of differentiation 38 (CD38) that have been implicated in lethal mdx response to pharmacological β-adrenergic receptor agonism. However, genetic CD38 ablation did not prevent mdx scruff-induced inactivity. Our data do not support a direct contribution by the kynurenine pathway or CD38 metabolic dysfunction to the exaggerated stress response of mdx mice.

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.

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.

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.

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.

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.

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.

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.

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.

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.

Total knee replacement including a modular distal femoral component in elderly patients with acute fracture or nonunion

Distal femoral fracture or nonunion in elderly patients with osteopenic bone and coexisting gonarthrosis poses a difficult treatment challenge. Open reduction and internal fixation with or without the use of bone cement may not provide sufficient stabilization, requires a prolonged period of weightbearing restrictions, and does not address preexisting knee arthrosis. We report five patients, three with distal femoral nonunion, two with acute distal femoral fracture, and all with concomitant gonarthrosis treated with total knee replacement including a modular distal femoral component [distal femoral replacement (DFR)]. In this group of patients, modular DFR provided immediate pain relief and allowed early weightbearing and aggressive rehabilitation. We recommend this treatment modality in selected osteopenic elderly patients with difficult distal femoral reconstructive problems and coexisting gonarthrosis.

Radiographic analysis of tibial fracture malalignment following intramedullary nailing

Intramedullary nailing of the tibia was performed on 145 tibiae (137 patients) for fracture or nonunion from 1985 to 1992. There were 133 cases available for radiographic analysis of postoperative tibial alignment. Of the 133 nailings, 16 (12%) were malaligned (12 acute fractures and 4 nonunion-malunions). Malalignment was defined as 5 degrees angulatory deformity in any plane. Malalignment was seen in 58% of proximal third fractures, 7% of middle third fractures, and 8% of distal third fractures. Of the malaligned fractures, 83% were either segmental or comminuted. Thirteen percent of the reamed tibiae were malaligned as compared with 9% of the unreamed tibiae. There was no relationship between nail insertion site and degree of angulation. The medial entrance angle averaged 9.5 degrees and contributed to a valgus deformity in 4 proximal third tibial fractures. The average anterior bow deformity of 5 proximal third fractures was 7 degrees (range, 5 degrees-12 degrees). Careful attention to operative technique and entrance angle, particularly with proximal third or comminuted fractures, is recommended to prevent angular deformity and malunion after tibial nailing. Proximal third tibial fractures may require a neutral or slightly lateral entrance angle to ensure a more anatomic reduction and centromedullary nail orientation to offset the tendency for valgus angulation.

Characterization of the deoxycytidine kinase promoter in human lymphoblast cell lines

Deoxycytidine kinase (dCK) phosphorylates 2'-deoxycytidine, as well as the purine deoxyribonucleosides and a number of nucleoside analogues that are important in the chemotherapy of leukemias. The enzyme is highly expressed in the thymus relative to other tissues and may play an important role in the T cell depletion associated with adenosine deaminase and purine nucleoside phosphorylase deficiencies. To characterize the dCK promoter region and to determine whether it mediates higher levels of gene expression in T lymphoblasts, we have analyzed a 700-bp genomic fragment encompassing 548 bp of 5' flanking region for functional activity and for transcription factor binding using T and B lymphoblast cell lines and nuclear extracts. The regions of the promoter that were defined as important to its function include a 5' GC box, and E box, a 3' GC box, and an E2F site. The transcription factor Sp1 binds to both GC boxes, activating at the 5' site but repressing at the 3' site. MLTF/USF activates transcription through the E box, whereas E2F activates through the E2F site, but binds weakly to this site in vitro and does not appear to mediate cell cycle-specific expression of dCK in vivo. No significant differences in promoter activity or transcription factor binding were observed between Jurkat T and Raji B lymphoblasts. The promoter of the dCK gene is thus regulated by a number of ubiquitously expressed transcription factors. DCK expression in cultured lymphoblast cell lines is not solely a function of the T or B lineage derivation.

Improving mental fitness reports of candidates for police officer and fire fighter

On the basis of 18 years of experience on the Medical Review Panel of the New Jersey Department of Personnel, the author points out some shortcomings commonly observed in psychological/psychiatric evaluative reports on mental fitness of police officer and fire fighter candidates. Each shortcoming is noted under one of two headings, i.e., routine information or inferences.

True three dimensional stereographic display of 3D reconstructed CT scans of the pelvis and acetabulum

Fractures of the acetabulum can cause the pelvis to shatter into a wide array of complex configurations which can be difficult to fully delineate preoperatively. In addition to plain radiography and standard computed tomography, technology now allows the reconstruction of magnetic resonance imaging (MRI) and computed tomography (CT) data into virtual objects; three dimensional (3D) representations of anatomy which exist only within the computer memory. Printouts and photographs of 3D reconstructions provide another level of anatomic information to the orthopaedic surgeon. However, current standard displays such as computer and video screens and photographic and radiographic film are all two dimensional (2D) modalities. Displaying 3D reconstructions in this standard 2D fashion, inescapably robs the images of up to one third of the information contained within them--all the true depth information which is the essence of 3D. Shading techniques and perspective have both been utilized to simulate depth, but true depth is still lacking. Recently, the authors have begun using a technique of computerized 3D reconstruction and recording which provides a true 3D display of the reconstructed images. The resultant gain in image realism is profound, somewhat similar to hearing full stereo audiophonic recording compared to monophonic, or to seeing in color rather than black and white. The image generation and display process is a computerized mathematical adaptation of the photographic technique of stereophotography. Once in place, the technique is relatively simple to use and can be achieved in several ways with a minimum of additional hardware. Potential benefits lie in the method's ability to convey, in one 3D display, the true 3D, spatial anatomic configuration of the imaged pelvis. The methods described are common to those forming the fundamental basis for virtual reality imaging. Current users of some 3D reconstruction systems can now easily generate images which can be viewed with all of the depth information restored, into a true 3D display.

Heterotopic ossification prophylaxis following operative treatment of acetabular fracture

Eighty seven patients with 88 fractures were retrospectively reviewed to assess the effect of postoperative prophylaxis on the formation of heterotopic ossification (HO). Sixty eight patients with 69 acetabular fractures were followed for an average of 21 months (range, 3-98 months). The grade of HO was assessed using the Brooker classification system. Thirty four fractures had no prophylactic treatment, 30 were treated prophylactically with indomethacin, two with radiation therapy, and three with both indomethacin and radiation. Twenty (59%) of 34 untreated fractures developed HO, of which nine (26%) were Grade III or IV. Thirteen (43%) of 30 fractures treated with indomethacin developed HO, of which 5 (16%) were Grade III and none were Grade IV. Twenty one of 24 fractures were stabilized through the extended iliofemoral approach; 13 of these had no prophylaxis. Eleven of the 13 developed HO; eight were Grade III or IV (62%). Seven of eight fractures treated with indomethacin following the extended iliofemoral approach developed HO; one was Grade III (13%) and non Grade IV. There was no significant difference between 13 patients who were not treated prophylactically and 18 indomethacin treated patients stabilized through the Kocher-Langenbeck approach. Only one of 11 patients had HO (Grade I) following an ilioinguinal approach. Postoperative radiation therapy, with or without indomethacin, resulted in three patients with Grade 0 HO (all radiated 1-4 days post surgery), one with Grade II (radiated postoperative Day 8), and one with Grade III HO (significant delay in surgery with preoperative Grade III HO of the hip).(ABSTRACT TRUNCATED AT 250 WORDS)

Surgical revision of malreduced acetabular fractures

Early failure of open reduction and internal fixation of fractures of the acetabulum presents a treatment challenge even more difficult than that of the primary injury. This study evaluates the success of reoperation for 64 patients with surgical malreduction or secondary loss of reduction. In 36 patients (56%) the reconstruction achieved was within 2 mm of being anatomic as judged by plain radiography. Overall, 27 patients (42%) had excellent or good outcomes at an average 4.2 year followup. Delay to reoperation appeared to have an adverse affect on the result of surgery. At followup 57% of patients reoperated on within 3 weeks of injury were rated good or excellent. This figure dropped to 29% when the delay exceeded 12 weeks. These data do not compare favorably with results obtained in large series of singly operated fractures; however, they do indicate that it is possible to salvage a significant number of failed open reductions by reoperation.

Delayed reconstruction of acetabular fractures 21-120 days following injury

A retrospective review was performed of 207 patients treated by delayed reconstruction of acetabular fracture between 21 and 120 days following injury. Nineteen patients were lost to followup. One hundred eighty seven patients had 188 fractures classified as follows; 35 posterior wall, 9 posterior column, 5 anterior wall, 4 anterior column, 13 transverse, 49 transverse/posterior wall, 21 T shape, 8 posterior column/posterior wall, 8 anterior column posterior hemitransverse, and 34 both column fractures. The average preoperative delay was 43 days. Followup averaged 6.5 years (range, 9 months-30 years). Overall good to excellent results were achieved in 65% of patients, fair in 9%, and poor in 26%. Good to excellent results by fracture type were; posterior wall (51%), posterior column (89%), anterior wall (60%), anterior column (100%), transverse (69%), transverse/posterior wall (59%), T shape (62%), posterior column/posterior wall (88%), anterior column/posterior hemitransverse (75%), and both column (72%). Heterotopic ossification developed in 49 of 168 patients without prophylactic treatment, in 6 of 12 treated prophylactically with diphosphonate, and in 2 of 27 receiving prophylactic indomethacin therapy. There were 20 postoperative sciatic nerve palsies, 3 immediate and 5 delayed infections, 5 cases of pulmonary embolism, and 26 cases of avascular necrosis. Delayed management of acetabular fractures increases the difficulty of operative treatment and may result in a significant reduction in good to excellent results. Simple anterior or posterior wall fractures, associated transverse + posterior wall fractures, and T shape fractures have an increased risk of failure when treated within this time period.

The use of the unreamed nail in tibial fractures with concomitant preoperative or intraoperative elevated compartment pressure or compartment syndrome

Twelve patients with tibial shaft fractures and evidence of compartment syndrome or with documented elevated compartment pressures were treated with an unreamed locked intramedullary nail and a single-incision lateral four-compartment fasciotomy. There were six closed fractures and three grade I and three grade II open fractures. Ten fractures have achieved a solid union without shortening or significant angulation at an average follow-up of 8.1 months (range 4-26). Two patients were lost to follow-up. There were two delayed unions and one nonunion, all of which healed after additional treatment. Average time to tibial union was 5.8 months (range 2-24), with six fractures healing in < or = 4 months. One patient whose treatment was delayed > 12 h after his injury has a persistent neurologic deficit with a claw toe deformity. There were no superficial or deep infections. All patients obtained an excellent range of motion of the knee and ankle. Unreamed nailing of diaphyseal tibial fractures with an associated compartment syndrome provides optimal internal fixation while allowing excellent access for soft tissue care. We believe that the unreamed tibial nail, when combined with a single-incision, lateral, four-compartment fasciotomy, offers substantial advantage in the treatment of this injury, permitting optimal treatment of a difficult fracture and soft tissue injury.

Acute lengthening of shortened lower extremities after malunion or non-union of a fracture

Forty-nine skeletally mature patients who had either a non-union or a malunion of a fracture of the tibia or the femur had correction of the deformity and acute axial lengthening of the fractured bone. Distraction was provided by the short AO/ASIF fracture distractor applied directly to the site of the osteotomy or non-union. At an average of sixty-three months (range, twenty-six to 105 months), the average increase in the tibial and femoral length was 1.7 and 3.2 centimeters, respectively. There were no compartment syndromes or ischemia secondary to any of the procedures. One patient had a transient sensory-nerve loss. Fatigue fractures were seen in two tibial plates, two femoral plates, and one femoral intramedullary nail used for osteosynthesis. A non-union developed after four other femoral intramedullary nailing procedures. One infection developed after lengthening of a tibia. Restoration of normal length by acute lengthening and internal fixation was achieved in twenty-seven patients. One patient had overlengthening of one centimeter. Fifteen patients had residual shortening of approximately one centimeter, three had shortening of more than one to 2.5 centimeters, and three patients had more than 2.5 centimeters of shortening. The patients in this series had acute restoration of limb length after traumatic shortening with a low prevalence of complications of neurovascular compromise. Three of the thirty tibial lengthenings and seven of the nineteen femoral lengthenings had to be followed by at least one additional procedure to obtain union.

Efficient electrode spacing for examining spatial organization during ventricular fibrillation

Spatial organization has been observed during episodes of ventricular fibrillation (VF) by recording epicardial unipolar electrograms on a grid of electrodes. In such studies, the choice of spacing between electrodes is an important decision, affecting the resolution and the size of the domain to be studied. A basic tenet of sampling theory, the Nyquist criterion, states that an electrode spacing smaller than half the smallest significant wavelength is required to capture the important details of a spatially sampled process. In this paper, we suggest a method to choose a practical interelectrode spacing by examining wavenumber power spectra of high-resolution VF data recorded from a square 11 x 11 array of electrodes spaced 0.28 mm apart. The plaque was sutured on the epicardium near the left ventricular apex in seven anesthetized pigs. VF was induced with ac simulation. Unipolar extracellular electrograms were simultaneously recorded from each channel for 2 s after the induction of VF. Each signal was sampled in time at 1000 Hz. Wavenumber power spectra were calculated for 100 ms segments using the zero-delay wavenumber spectrum method, for a total of 140 power spectra. All spectra had dominant peaks at the origin and fell off rapidly with increasing wavenumber (decreasing wavelength). In all the spectra, every wavelength shorter than 1.4 mm contributed insignificant power. Furthermore, in 134 of 140 spectra (96%), insignificant power levels were associated with every wavelength shorter than 2.8 mm. These results suggest that, for unipolar extracellular electrodes, an intersensor spacing on the order of 1 mm is appropriate to study organization during early VF.

A quantitative measurement of spatial order in ventricular fibrillation

INTRODUCTION

The degree of organization in ventricular fibrillation (VF) is not known. As an objective measurement of spatial order, spatial correlation functions and their characteristic lengths were estimated from epicardial electrograms of pigs in VF.

METHODS AND RESULTS

VF was induced by premature stimulation in five pigs. Electrograms were simultaneously recorded with a 22 x 23 array of unipolar electrodes spaced 1.12 mm apart. Data were obtained by sampling the signals at 2000 Hz for 20 minutes immediately after the initiation of FV. Correlations between all pairs of signals were computed at various times. Correlation lengths were estimated from the decay of average correlation as a function of electrode separation. The correlation length of the VF in pigs was found to be approximately 4 to 10 mm, varying as fibrillation progressed. The degree of correlation decreased in the first 4 seconds after fibrillation then increased over the next minute.

CONCLUSION

The correlation length is much smaller than the scale of the heart, suggesting that many independent regions of activity exist on the epicardium at any one time. On the other hand, the correlation length is 4 to 10 times the interelectrode spacing, indicating that some coherence is present. These results imply that the heart behaves during VF as a high dimensional, but not random, system involving many spatial degrees of freedom, which may explain the lack of convergence of fractal dimension estimates reported in the literature. Changes in the correlation length also suggest that VF reorganizes slightly in the first minute after an initial breakdown in structure.

Synovial metallosis resulting from intraarticular intramedullary nailing of a distal femoral nonunion

An 80-year-old man sustained a T-shaped supracondylar fracture of the femur associated with distal one-third shaft comminution. Initial failure of a 95 degrees angle blade plate was followed by insertion of an intraarticular intramedullary nail stabilized with static locking-screw fixation. A second failure of the implant was treated by extraarticular tension band condylar buttress plate osteosynthesis. Severe knee synovial metallosis was found at the time of removal of the intraarticular nail device.

Open ankle fractures. The indications for immediate open reduction and internal fixation

Twenty-two patients with open ankle fractures or fracture-dislocations were treated with irrigation and debridement, reduction, and immediate stable internal fixation at an average of six hours from initial evaluation. There were 13 women (59%) and nine men (41%), having an average follow-up period of 32 months (range, five to 111 months). There were six Grade I (27%), 15 Grade II (68%), and one Grade III (5%) injuries. Fractures also were classified according to the Danis-Weber scheme (Type A [three cases]; Type B [eight]; Type C [11]). Excellent results were achieved in 14 patients (64%); good results in five (23%), and poor results in three (13%). There were four minor complications: two superficial would ulcerations, one loss of reduction requiring revision stabilization, and one distal tibiofibular synostosis. There were no deep infections or nonunions. Immediate debridement, irrigation, reduction, and internal fixation of open ankle fractures is clearly indicated in Grade I and clean Grade II open injuries.

Surgical management of calcaneal fractures using bilateral incisions and minimal internal fixation

Nine patients with displaced calcaneal fractures were approached through bilateral incisions and stabilized with minimal internal fixation. All patients were men, with an average age of 35 years (range, 19-65). All fracture patterns had three-part split depression fractures of the posterior facet, a single intact sustentacular tali fragment, middle facet, and anterior body fractures. The reduction of tubercle impaction and varus angulation was accomplished by stabilization of the sustentacular tali-posterior tubercle fracture line through a modified medial vertical incision. Minimal fixation using either a three-prong staple or 4-mm lag screws was sufficient to stabilize this fracture pattern. Posterolateral facet articular elevation, and final reconstruction of Böhler's and Gissane's angles were performed through an extended lateral incision. Five of nine calcanei were stabilized with lag screws only and four required minimal lateral plate osteosynthesis. Preoperative Böhler's and Gissane's angles averaged 6 degrees and 138 degrees; postoperative angles averaged 34 degrees and 123 degrees, respectively. The average difference between postoperative Böhler's and Gissane's angles compared with the normal contralateral side was 1 degree each. There was no loss of reduction, and healing was uneventful. There was anatomic reconstruction of both medial and lateral cortexes in all cases. In this specific fracture pattern, medial stabilization of the sustentacular talitubercle fracture line can reduce both the amount and extent of lateral fixation, facilitate anatomic reduction of the posterior facet, and reduce postoperative implant sequelae after internal fixation.

Ipecac myopathy and cardiomyopathy

Two cases of ipecac myopathy, one with associated cardiomyopathy are reported. Both patients were young women with eating disorders who came to medical attention because of diffuse muscle weakness. Clinical and electromyographic data suggested ipecac myopathy and muscle biopsies confirmed this diagnosis. One patient had associated clinical and echocardiographic evidence of significant cardiomyopathy. The myopathy resolved and the echocardiogram returned to normal after discontinuing the use of ipecac.

Estimating the 95% effective defibrillation dose

Minimum squared error (MinSE) testing protocols and a MinSE estimator are presented which accurately estimate the voltage that defibrillates 95% of the time (the ED95). The MinSE experimental procedures, presented in the form of lookup tables, detail the response to successful and unsuccessful trials. The lookup tables also show the ED95 estimates calculated from the observed results using the MinSE estimator. Two assumptions are required to develop the look-up tables: 1) the dose-response curve, chosen using a statistical analysis of a retrospective sample, and 2) the distribution of the ED95's in the population. The MinSE estimator and experimental procedure are examined in a prospective study of five dogs (19-25 kg, heart weights 139.3-236.9 gm) using nonthoracotomy implantable defibrillator electrodes and a biphasic defibrillation waveform (3.5 ms first phase, 2.0 ms second phase). Employing an ED95 population distribution assumption applicable to most implantable defibrillator electrodes and waveforms, e.g., the ED95 is between 0.0 and 800.0 V, the measured rms error was 15% of the mean measured ED95 for the MinSE, four test shock, ED95 estimates. If the protocols are designed with an ED95 population distribution assumption for animals of the same species and size, and defibrillation is constrained to one electrode configuration and waveform, the estimates improve by 3.8%. Using techniques from the Bayesian statistics literature, the MinSE approach can be extended to a variety of defibrillation parameter estimation problems.

Genomic structure and chromosomal localization of the human deoxycytidine kinase gene

Deoxycytidine kinase (NTP:deoxycytidine 5'-phosphotransferase, EC 2.7.1.74) is an enzyme that catalyzes phosphorylation of deoxyribonucleosides and a number of nucleoside analogs that are important in antiviral and cancer chemotherapy. Deficiency of this enzyme activity is associated with resistance to these agents, whereas increased enzyme activity is associated with increased activation of such compounds to cytotoxic nucleoside triphosphate derivatives. To characterize the regulation of expression of this gene, we have isolated genomic clones encompassing its entire coding and 5' flanking regions and delineated all the exon/intron boundaries. The gene extends over more than 34 kilobases on chromosome 4 and the coding region is composed of 7 exons ranging in size from 90 to 1544 base pairs (bp). The 5' flanking region is highly G+C-rich and contains four regions that are potential Sp1 binding sites. A 697-bp fragment encompassing 386 bp of 5' upstream region, the 250-bp first exon, and 61 bp of the first intron was demonstrated to promote chloramphenicol acetyltransferase activity in a T-lymphoblast cell line and to have > 6-fold greater activity in a Jurkat T-lymphoblast than in a Raji B-lymphoblast cell line. Our data suggest that these 5' sequences may contain elements that are important for the tissue-specific differences in deoxycytidine kinase expression.

Regulation of human deoxycytidine kinase expression

The human deoxycytidine kinase gene is a single copy gene and is comprised of seven exons that are spread over more than 34 kb of the genome. The 5'-flanking region is highly G/C rich and does not contain CAAT or TATA boxes. This region, when cloned into a recorder gene construct containing the chloramphenicol acetyltransferase gene, is capable of mediating CAT activity in human lymphoid cell lines and appears to have greater activity in human T, as compared to B, lymphoblast cell lines. The expression of the gene at the mRNA level does not appear to be cell-cycle regulated in that the levels of mRNA in human peripheral blood T lymphocytes remain constant as the cells progress from a resting to a proliferating state. Since this enzyme catalyzes the conversion of a number of chemotherapeutic agents to their corresponding monophosphate form and is thus essential for their activation, it will be important to define further the genetic elements which regulate the expression of this gene.

Does spousal participation in Gamblers Anonymous benefit compulsive gamblers?

Extent of gambling-free periods was compared for 90 compulsive gamblers, 44 with spouses who participated in Gamblers Anonymous and 46 with spouses who did not. Although the results were in the direction of a beneficial effect of spousal participation, the relationship was statistically nonsignificant.

The treatment of infected nonunions and segmental defects of the tibia by the methods of Ilizarov

Circular external fixation using the Ilizarov apparatus combined with internal bone transport or compression-distraction techniques were used to treat 28 patients with infected nonunions or segmental bone loss of the tibia. There were 22 males and six females with an average age of 34 years (range, 17-58 years). Six of 28 patients had infected tibial nonunions associated with hemicircumferential bone loss. These tibiae were treated by anterior hemicircumferential corticotomy and partial bone fragment internal transport. Fifteen of the remaining 22 patients had an average of 4 cm of segmental bone loss (range, 2-7 cm). Seven patients without shortening or defect had infected nonunions associated with extensive diaphyseal sequestrae. These nonunions were treated by en bloc resection of the diaphyseal shaft and internal bone transport. All patients healed their infected extremities without the addition of cancellous bone graft, microvascular fibular, or soft-tissue grafting. Preoperative shortening was present in 13 of 28 patients. Regenerate new bone formation averaged 6 cm (range, 1.5-22 cm). Postoperative antibiotics were not administered in 21 of 28 patients. In seven patients, antibiotics were given for ten days after en bloc resection of the diaphyseal sequestrae. Equal limb length was maintained in 21 extremities, within 1 cm in five tibiae and less than 3 cm in two tibiae. Functional results were good to excellent in 21, fair in six, and poor in one. The application of Ilizarov techniques to diaphyseal infected nonunions and segmental defects is very encouraging. It may prove to be an excellent technique for future management of resistant diaphyseal infections of bone.

The Rotter I-E scale as a predictor of relapse in a population of compulsive gamblers

Profile surveys, completed Rotter I-E scales, and questionnaires on past relapse behavior were collected from 108 New Jersey compulsive gamblers who attended Gamblers Anonymous, and an attempt was made, based on the findings, to predict incidence of compulsive gamblers' relapse. Relationships between I-E scores and extent of relapse-free periods, and I-E scores and relapse, with the variables of religious background, age, marital status, education, type of work, and childhood physical abuse were investigated. In every instance the relationship found was statistically non-significant.

Effect of pulse separation between two sequential biphasic shocks given over different lead configurations on ventricular defibrillation efficacy

BACKGROUND

Two sequential biphasic shocks delivered over separate lead configurations markedly improve defibrillation efficacy compared with a single shock alone. We investigated the effect of varying the intershock interval between sequential biphasic shocks on defibrillation.

METHODS AND RESULTS

Defibrillation thresholds (DFTs) were obtained in six dogs for shock separations ranging from 0.2 to 125 msec. The first shock was given from a catheter electrode in the right ventricular apex to a patch on the left lateral thorax; the second was from a small patch on the left ventricular apex to a catheter electrode in the right ventricular outflow tract. When the interval between shocks was less than or equal to 10 msec or greater than or equal to 75 and less than or equal to 125 msec, the mean DFTs were less than that previously found for the first shock by itself (4.2 versus 7.4 J, p = 0.002). At a separation of 50 msec, however, there was a marked rise in the DFT to 27 J. The mean DFT for the second shock at a delay of 50 msec was not different from the mean DFT previously found for the second shock by itself (7.2 versus 7.0 J). These results were confirmed in another six dogs using defibrillation probability-of-success curves. In 12 other dogs, probability-of-success curves were generated for delays between shocks as a percentage of the activation interval during ventricular fibrillation. Minimum defibrillation energy requirements were at two separations, 0.2 msec and 90% of the activation interval.

CONCLUSIONS

The optimal intershock interval between two sequential biphasic shocks is either less than or equal to 10 msec or greater than or equal to 75 and less than or equal to 125 msec. The marked rise in the DFT at a shock separation of 50 msec, requiring more energy than that for the first shock alone, suggests that the second shock at this time delay is likely to reinduce fibrillation after it is halted by the first shock until the second shock is strong enough to defibrillate independently of the first shock.

Resistant nonunions and partial or complete segmental defects of long bones. Treatment with implants of a composite of human bone morphogenetic protein (BMP) and autolyzed, antigen-extracted, allogeneic (AAA) bone

Twenty-five patients with resistant nonunions including partial or complete segmental defects were treated with a composite alloimplant of human bone morphogenetic protein (h-BMP) and autolyzed, antigen-free, allogeneic bone (AAA). The series consisted of 16 females and nine males; average age was 45 years. Preoperative symptoms averaged 30 months (range, five to 83 months); 22 of 25 patients had failed multiple attempts at electrical stimulation. Twenty-three of 25 patients had an average of three prior failed surgical attempts at union (range, one to ten). There were ten segmental defects with an average length of 4 cm (range, 2-9 cm). The composite implant was incorporated as an onlay in 15 extremities and as an inlay graft supported by internal fixation in ten extremities. Seven patients received supplementary autogeneic cancellous bone grafting. Average healing time was six months (range, three to 14 months). Average follow-up time was 21 months (range, five to 82 months). Functional results were rated as excellent, 14; good, five; and fair, five. One failed to unite because of a recurrent infection. Union was obtained in 24 of 25 patients. There were five failures of the original operation that required reoperations; union eventually occurred in four of five extremities by repeat composite grafting and replacement of the failed internal fixation. Bony union between host bone and the composite implant began at an average of eight weeks postoperatively. Present results indicate that h-BMP/AAA composite implants represent adjunctive treatment of difficult nonunions. The h-BMP/AAA composite implants may be implanted in either partial or complete segmental defects of long bones.(ABSTRACT TRUNCATED AT 250 WORDS)

Comparison of two locus of control scales in predicting relapse in an alcoholic population

A 3-mo. follow-up was made of 64 male veterans who were discharged from a 21-day Alcohol Detoxification Treatment Program at the Veterans Affairs Medical Center at Lyons, NJ. Scores on the Rotter I-E and Alcohol Responsibility Scales were significantly correlated with tendencies toward a more external direction among the 13% who relapsed, significant on the I-E scale and nonsignificant on the Alcohol Responsibility Scale. When tests were compared as possible predictor variables of alcoholic relapse, the difference in favor of the I-E scale was statistically nonsignificant.