Lessons Learned From the First-In-Human Compassionate Use of Connect-EA™ in Ten Patients With Esophageal Atresia

INTRODUCTION

Delayed primary repair of esophageal atresia in patients with high-risk physiologic and anatomic comorbidities remains a daunting challenge with an increased risk for peri-operative morbidity and mortality via conventional repair. The Connect-EA device facilitates the endoscopic creation of a secure esophageal anastomosis. This follow-up study reports our long-term outcomes with the novel esophageal magnetic compression anastomosis (EMCA) Connect-EA device for EA repair, as well as lessons learned from the ten first-in-human cases. We propose an algorithm to maximize the advantages of the device for EA repair.

METHODS

Under compassionate use approval, from June 2019 to December 2022, ten patients with prohibitive surgical or medical risk factors underwent attempted EMCA with this device. All patients underwent prior gastrostomy, tracheoesophageal fistula ligation (if necessary), and demonstrated pouch apposition prior to EMCA.

RESULTS

Successful device deployment and EMCA formation were achieved in nine patients (90%). Mean time to anastomosis formation was 8 days (range 5-14) and the device was retrieved endoscopically in five (56%) cases. At median follow-up of 22 months (range 4-45), seven patients (78%) are tolerating oral nutrition. Balloon dilations (median 4, range 1-11) were performed either prophylactically for radiographic asymptomatic anastomotic narrowing (n = 7, 78%) or to treat clinically-significant anastomotic narrowing (n = 2, 22%) with no ongoing dilations at 3-month follow up post-repair.

CONCLUSION

EMCA with the Connect-EA device is a safe and feasible minimally-invasive alterative for EA repair in high-risk surgical patients. Promising post-operative outcomes warrant further Phase I investigation.

LEVEL OF EVIDENCE

IV, Case series of novel operative technique without comparison group.

Benchmarking Pediatric Trauma Care in Mixed Trauma Centers: Adult Risk-Adjusted Mortality Is Not a Reliable Indicator of Pediatric Outcomes

BACKGROUND

Trauma center benchmarking has become standard practice for assessing quality. The American College of Surgeons adult trauma center verification standards do not specifically require participation in a pediatric-specific benchmarking program. Centers that treat adults and children may therefore rely solely on adult benchmarking metrics as a surrogate for pediatric quality. This study assessed discordance between adult and pediatric mortality within mixed trauma centers to determine the need to independently report pediatric-specific quality metrics.

STUDY DESIGN

A cohort of trauma centers (n = 493, including 347 adult-only, 44 pediatric-only, and 102 mixed) that participated in the American College of Surgeons TQIP in 2017 to 2018 was analyzed. Center-specific observed-to-expected mortality estimates were calculated using TQIP adult inclusion criteria for 449 centers treating adults (16 to 65 years) and using TQIP pediatric inclusion criteria for 146 centers treating children (0 to 15 years). We then correlated risk-adjusted mortality estimates for pediatric and adult patients within mixed centers and evaluated concordance of their outlier status between adults and children.

RESULTS

The cohort included 394,075 adults and 97,698 children. Unadjusted mortality was 6.1% in adults and 1.2% in children. Mortality estimates had only moderate correlation ( r = 0.41) between adult and pediatric cohorts within individual mixed centers. Mortality outlier status for adult and pediatric cohorts was discordant in 31% (32 of 102) of mixed centers (weighted Kappa statistic 0.06 [-0.11 to 0.22]), with 78% (23 of 32) of discordant centers having higher odds of mortality for children than for adults (6 centers with average adult mortality and high pediatric mortality and 17 centers with low adult mortality and average pediatric mortality, p < 0.01).

CONCLUSIONS

Adult mortality is not a reliable surrogate for pediatric mortality in mixed trauma centers. Incorporation of pediatric-specific benchmarks should be required for centers that admit children.

Evaluation of a Magnetic Compression Anastomosis for Jejunoileal Partial Diversion in Rhesus Macaques

PURPOSE

Metabolic surgery remains underutilized for treating type 2 diabetes, as less invasive alternative interventions with improved risk profiles are needed. We conducted a pilot study to evaluate the feasibility of a novel magnetic compression device to create a patent limited caliber side-to-side jejunoileal partial diversion in a nonhuman primate model.

MATERIALS AND METHODS

Using an established nonhuman primate model of diet-induced insulin resistance, a magnetic compression device was used to create a side-to-side jejunoileal anastomosis. Primary outcomes evaluated feasibility (e.g., device mating and anastomosis patency) and safety (e.g., device-related complications). Secondary outcomes evaluated the device's ability to produce metabolic changes associated with jejunoileal partial diversion (e.g., homeostatic model assessment of insulin resistance [HOMA-IR] and body weight).

RESULTS

Device mating, spontaneous detachment, and excretion occurred in all animals (n = 5). There were no device-related adverse events. Upon completion of the study, ex vivo anastomoses were widely patent with healthy mucosa and no evidence of stricture. At 6 weeks post-device placement, HOMA-IR improved to below baseline values (p < 0.05). Total weight also decreased in a linear fashion (R2 = 0.97) with total weight loss at 6 weeks post-device placement of 14.4% (p < 0.05).

CONCLUSION

The use of this novel magnetic compression device to create a limited caliber side-to-side jejunoileal anastomosis is safe and likely feasible in a nonhuman primate model. The observed glucoregulatory and metabolic effects of a partial jejunoileal bypass with this device warrant further investigation to validate the long-term glucometabolic impact of this approach.

Beyond the gut: spectrum of magnetic surgery devices

Since the 1970s, magnetic force has been used to augment modern surgical techniques with the aims of minimizing surgical trauma and optimizing minimally-invasive systems. The majority of current clinical applications for magnetic surgery are largely centered around gastrointestinal uses-such as gastrointestinal or bilioenteric anastomosis creation, stricturoplasty, sphincter augmentation, and the guidance of nasoenteric feeding tubes. However, as the field of magnetic surgery continues to advance, the development and clinical implementation of magnetic devices has expanded to treat a variety of non-gastrointestinal disorders including musculoskeletal (pectus excavatum, scoliosis), respiratory (obstructive sleep apnea), cardiovascular (coronary artery stenosis, end-stage renal disease), and genitourinary (stricture, nephrolithiasis) conditions. The purpose of this review is to discuss the current state of innovative magnetic surgical devices under clinical investigation or commercially available for the treatment of non-gastrointestinal disorders.

The Evolving Use of Magnets in Surgery: Biomedical Considerations and a Review of Their Current Applications

The novel use of magnetic force to optimize modern surgical techniques originated in the 1970s. Since then, magnets have been utilized as an adjunct or alternative to a wide array of existing surgical procedures, ranging from gastrointestinal to vascular surgery. As the use of magnets in surgery continues to grow, the body of knowledge on magnetic surgical devices from preclinical development to clinical implementation has expanded significantly; however, the current magnetic surgical devices can be organized based on their core function: serving as a guidance system, creating a new connection, recreating a physiologic function, or utilization of an internal–external paired magnet system. The purpose of this article is to discuss the biomedical considerations during magnetic device development and review the current surgical applications of magnetic devices.

Standardized perioperative care reduces colorectal surgical site infection in children: A Western Pediatric Surgery Research Consortium multicenter analysis

PURPOSE

Surgical site infection (SSI) remains a significant source of patient morbidity and resource utilization in children undergoing colorectal surgery. We examined the utility of a protocolized perioperative care bundle in reducing SSI in pediatric patients undergoing colorectal surgery.

METHODS

We conducted a prospective cohort study of patients ≤18 years of age undergoing colorectal surgery at ten United States children's hospitals. Using a perioperative care protocol comprising eight elements, or "colon bundle", we divided patients into low (1-4 elements) or high (5-8 elements) compliance cohorts. Procedures involving colorectal repair or anastomosis with abdominal closure were included. Demographics and clinical outcomes were compared between low and high compliance cohorts. Compliance was compared with a retrospective cohort. The primary outcome was superficial SSI incidence at 30 days.

RESULTS

Three hundred and thirty-six patients were included in our analysis: 138 from the low compliance cohort and 198 from the high compliance cohort. Age and gender were similar between groups. Preoperative diagnosis was similar except for more patients in the high compliance cohort having inflammatory bowel disease (18.2% versus 5.8%, p<0.01). The most common procedure performed was small bowel to colorectal anastomosis. Wound classification and procedure acuity were similar between groups. Superficial SSI at 30 days occurred less frequently among the high compliance compared to the low compliance cohort (4% versus 9.7%, p = 0.036). Median postoperative length of stay and 30-day rates of readmission, reoperation, intra-abdominal abscess and anastomotic leak requiring operation were not significantly different between groups. None of the individual colon bundle elements were independently protective against superficial SSI.

CONCLUSION

Standardization of perioperative care is associated with a reduction in superficial SSI in pediatric colorectal surgery. Expansion of standardized protocols for children undergoing colorectal surgery may improve outcomes and decrease perioperative morbidity.

TYPE OF STUDY

Clinical Research Paper LEVEL OF EVIDENCE: Level II.

The novel application of an emerging device for salvage of primary repair in high-risk complex esophageal atresia

INTRODUCTION

Preservation of native esophagus is a tenet of esophageal atresia (EA) repair. However, techniques for delayed primary anastomosis are severely limited for surgically and medically complex patients at high-risk for operative repair. We report our initial experience with the novel application of the Connect-EA, an esophageal magnetic compression anastomosis device, for salvage of primary repair in 2 high-risk complex EA patients. Compassionate use was approved by the FDA and treating institutions.

OPERATIVE TECHNIQUE

Two approaches using the Connect-EA are described - a totally endoscopic approach and a novel hybrid operative approach. To our knowledge, this is the first successful use of a hybrid operative approach with an esophageal magnetic compression device.

OUTCOMES

Salvage of delayed primary anastomosis was successful in both patients. The totally endoscopic approach significantly reduced operative time and avoided repeat high-risk operation. The hybrid operative approach salvaged delayed primary anastomosis and avoided cervical esophagostomy.

CONCLUSION

The Connect-EA is a novel intervention to achieve delayed primary esophageal repair in complex EA patients with high-risk tissue characteristics and multi-system comorbidities that limit operative repair. We propose a clinical algorithm for use of the totally endoscopic approach and hybrid operative approach for use of the Connect-EA in high-risk complex EA patients.

All body region injuries are not equal: Differences in pediatric discharge functional status based on Abbreviated Injury Scale (AIS) body regions and severity scores

PURPOSE

Functional outcomes have been proposed for assessing quality of pediatric trauma care. Outcomes assessments often rely on Abbreviated Injury Scale (AIS) severity scores to adjust for injury characteristics, but the relationship between AIS severity and functional impairment is unknown. This study's primary aim was to quantify functional impairment associated with increasing AIS severity scores within body regions. The secondary aim was to assess differences in impairment between body regions based on AIS severity.

METHODS

Children with serious (AIS≥ 3) isolated body region injuries enrolled in a multicenter prospective study were analyzed. The primary outcome was functional status at discharge measured using the Functional Status Scale (FSS). Discharge FSS was compared (1) within each body region across increasing AIS severity scores, and (2) between body regions for injuries with matching AIS scores.

RESULTS

The study included 266 children, with 16% having abnormal FSS at discharge. Worse FSS was associated with increasing AIS severity only for spine injuries. Abnormal FSS was observed in a greater proportion of head injury patients with a severely impaired initial Glasgow Coma Scale (GCS) (GCS< 9) compared to those with a higher GCS score (43% versus 9%; p < 0.01). Patients with AIS 3 extremity and severe head injuries had a higher proportion of abnormal FSS at discharge than AIS 3 abdomen or non-severe head injuries.

CONCLUSIONS

AIS severity does not account for variability in discharge functional impairment within or between body regions. Benchmarking based on functional status assessment requires clinical factors in addition to AIS severity for appropriate risk adjustment.

LEVEL OF EVIDENCE

1 (Prognostic and Epidemiological).

Functional status impairment at six-month follow-up is independently associated with child physical abuse mechanism

BACKGROUND

Children with abusive injuries have worse mortality, length-of-stay, complications, and healthcare costs compared to those sustaining an accidental injury. Long-term functional impairment is common in children with abusive head trauma but has not been examined in a cohort with heterogeneous body region injuries.

OBJECTIVE

To assess for an independent association between child physical abuse and functional impairment at discharge and six-month follow-up.

PARTICIPANTS AND SETTING

Seriously injured children (<15 years) treated at seven pediatric trauma centers.

METHODS

Functional status was compared between child physical abuse and accidental injury groups at discharge and six-month follow-up. Functional impairment was defined at discharge ("new domain morbidity") as a change from pre-injury ≥2 points in any of the six domains of the Functional Status Scale (FSS), and impairment at six-month follow-up as an abnormal total FSS score.

RESULTS

Children with abusive injuries accounted for 10.5% (n = 45) of the cohort. New domain morbidity was present in 17.8% (n = 8) of child physical abuse patients at discharge, with 10% (n = 3) of children having an abnormal FSS at six-months. There were no differences in new domain morbidity at hospital discharge between children injured by abuse and or accidental injury. However, children injured by physical abuse were 4.09 (2.15, 7.78) times more likely to have functional impairment at six months.

CONCLUSIONS

Child physical abuse is an independent risk factor for functional impairment at six-month follow-up. Functional status measurement for this high-risk group of children should be routinely measured and incorporated into trauma center quality assessments.

Torso vascular trauma

Vascular injury within the chest or abdomen represents a unique challenge to the pediatric general surgeon, as these life- or limb-threatening injuries are rare and may require emergent treatment. Vascular injury may present as life-threatening hemorrhage, or with critical ischemia from intimal injury, dissection, or thrombosis. Maintaining the skillset and requisite knowledge to address these injuries is of utmost importance for pediatric surgeons that care for injured children, particularly for surgeons practicing in freestanding children's hospitals that frequently do not have adult vascular surgery coverage. The purpose of this review is to provide an overview of torso vascular trauma, with a specific emphasis in rapid recognition of torso vascular injury as well as both open and endovascular management options. Specific injuries addressed include blunt and penetrating mediastinal vascular injury, subclavian injury, abdominal aortic and visceral segment injury, inferior vena cava injury, and pelvic vascular injury. Operative exposure, vascular repair techniques, and damage control options including preperitoneal packing for pelvic hemorrhage are discussed. The role and limitations of endovascular treatment of each of these injuries is discussed, including endovascular stent graft placement, angioembolization for pelvic hemorrhage, and resuscitative endovascular balloon occlusion of the aorta (REBOA) in children.

Novel Device for Endoluminal Esophageal Atresia Repair: First-in-Human Experience

Thoracoscopic esophageal atresia (EA) repair affords many benefits to the patient; however, intracorporeal suturing of the anastomosis is technically challenging. Esophageal magnetic compression anastomosis (EMCA) is a compelling option for endoluminal EA repair, but available EMCA devices have prohibitive rates of recalcitrant stricture. Connect-EA is a new endoluminal EMCA device system that employs 2 magnetic anchors with a unique mating geometry designed to reliably create a robust anastomosis and decrease rates of leak and stricture. We describe our first-in-human experience with this novel endoluminal device for staged EA repair in 3 patients (Gross type A, B, and C) at high risk for conventional surgical repair. First, the esophageal pouches were approximated thoracoscopically. After acute tension subsided, the device anchors were endoscopically placed in the esophageal pouches and mated. Anchors were spontaneously excreted in 2 cases. Endoscopic repositioning and retrieval of the anchors were required in 1 patient because of narrowed esophageal anatomy. There were no perioperative complications. Patients were managed for 14 to 18 months. The strictures that developed in the patients were membranous and responded well to dilation alone, resolving after 4 to 5 outpatient dilations. Gastrostomies were closed between 6 and 11 months and all patients are tolerating full oral nutrition. Early experience with this new endoluminal EMCA device system is highly favorable. The device offers considerable benefit over conventional handsewn esophageal anastomosis and anastomotic outcomes are superior to available EMCA devices.

Hospital-based intervention is rarely needed for children with low-grade blunt abdominal solid organ injury: An analysis of the Trauma Quality Improvement Program registry

BACKGROUND

Children with low-grade blunt solid organ injury (SOI) have historically been admitted to an inpatient setting for monitoring, but the evidence supporting the necessity of this practice is lacking. The purpose of this study was to quantify the frequency and timing of intervention for hemorrhage and to describe hospital-based resource utilization for low-grade SOI in the absence of other major injuries (OMIs).

METHODS

A cohort of children (aged <16 years) with blunt American Association for the Surgery of Trauma grade 1 or 2 SOI from the American College of Surgeons Trauma Quality Improvement Program registry (2007-2017) was analyzed. Children were excluded if they had confounding factors associated with intervention for hemorrhage (comorbidities, OMIs, or extra-abdominal surgical procedures). Outcomes included frequency and timing of intervention (laparotomy, angiography, or transfusion) for hemorrhage, as well as hospital-based resource utilization.

RESULTS

A total of 1,019 children were identified with low-grade blunt SOI and no OMIs. Nine hundred eighty-six (96.8%) of these children were admitted to an inpatient unit. Admitted children with low-grade SOI had a median length-of-stay of 2 days and a 23.9% intensive care unit admission rate. Only 1.7% (n = 17) of patients with low-grade SOI underwent an intervention, with the median time to intervention being the first hospital day. No child who underwent angiography was transfused or had an abnormal initial ED shock index.

CONCLUSION

Children with low-grade SOI are routinely admitted to the hospital and often to the intensive care unit but rarely undergo hospital-based intervention. The most common intervention was angiography, with questionable indications in this cohort. These data question the need for inpatient admission for low-grade SOI and suggest that discharge from the emergency room may be safe. Prospective investigation into granular risk factors to identify the rare patient needing hospital-based intervention is needed, as is validation of the safety of ambulatory management.

LEVEL OF EVIDENCE

Prognostic and epidemiological, level III.

Modern fetal surgery-a historical review of the happenings that shaped modern fetal surgery and its practices

The history of fetal surgery is one of constant evolution. Over the last 50 years, fetal surgery has progressed from a mere idea to an internationally respected innovative field of surgery. This article aims to provide a historical review of how the enterprise of maternal-fetal surgery came to be its modern version. This review is less focused on the history of specific therapies for a relatively small number of conditions, and more on how the whole field of maternal-fetal surgery evolved. The various internal and external influences that steered the field's evolution are discussed in chronologic order. Since the start of modern fetal surgery in the 1980s, large paradigm shifts have characterized the growth of the field as a whole. Innovative interventions are now based on physiologic manipulation as opposed to simple anatomic repair, fetoscopy has become the more frequently preferred surgical approach, and rigorous scientific evaluation with randomized controlled trials is now the standard expected by the community. In a very similar fashion to when the field first began in the early 1980s, recently community's leaders have risen to protect the integrity of maternal-fetal surgery by publishing ethical guidelines for innovation and clinical practice. This incredible history of innovation, rigorous science and ethical contemplation is the foundation on which modern maternal-fetal surgery rests.

Low falls: an underappreciated mechanism of injury

OBJECTIVE

This is a retrospective study designed to evaluate the pattern and severity of injuries that result from low falls, defined as falls from less than 20 ft, subsequent mortality, and requirements of hospital resources. Our hypothesis is that many of these injuries, even without cardiopulmonary instability, are worthy of trauma center care.

METHODS

The records of all patients entered into the hospital trauma registry at an urban Level I trauma center during the years 1991 through 1997 who suffered low falls and who either died after admission or were hospitalized for at least 3 days were reviewed. Patients suffering isolated hip fractures were excluded. One hundred seventy-six patients constituted the study population. This group accounts for about 2% of all admissions for falls at our institution. Patterns of injury were examined. Age, mechanism of injury, Injury Severity Score (ISS), and cardiopulmonary or neurologic instability on admission were documented. Mortality, length of intensive care unit and hospital stays, as well as billed hospital charges, were reviewed.

RESULTS

The majority of patients (62%) were younger than 50 years. Sixty patients had ISS >15 and 116 patients had ISS >9. Sixty patients had multisystem injuries requiring specialty care. Head injuries were found in 81 patients (35%), and vertebral fractures or spinal cord injuries were found in 49 patients (22%), including 9 quadriplegics and 5 paraplegics. There were seven patients with intra-abdominal injuries (five spleen and two bowel injuries). There was one patient with a rupture of the thoracic aorta. Seventeen patients had deteriorating neurologic or pulmonary function on arrival, but the majority (90%) were stable. Of the 159 "stable" patients, 48 suffered head injuries, 7 were quadriplegic, and 3 were paraplegic. All intra-abdominal injuries were in this group. Overall, 14 of 176 patients (8%) died. Seven deaths were in patients older than 60 years, and seven deaths were in younger patients (p = 0.04). The majority of deaths (9 of 14) were from head trauma. Care in the intensive care unit was required in 92 of 176 patients. Nine patients had billed charges exceeding $100,000.

CONCLUSION

Low falls can cause significant injuries, most commonly to the head and spine. Based on mechanism of injury alone, patients injured in low falls might not be taken to trauma centers. We have found, however, that many of these patients sustain serious multisystem injuries, even though they are stable initially. Although these patients represent only a fraction of those who fall, our study would support adjustment of triage guidelines to recommend transport of such patients, particularly elderly patients, to trauma centers.

Vesicle-associated brain myosin-V can be activated to catalyze actin-based transport

Myosin-V has been linked to actin-based organelle transport by a variety of genetic, biochemical and localization studies. However, it has yet to be determined whether myosin-V functions as an organelle motor. To further investigate this possibility, we conducted a biochemical and functional analysis of organelle-associated brain myosin-V. Using the initial fractionation steps of an established protocol for the purification of brain myosin-V, we isolated a population of brain microsomes that is approx. fivefold enriched for myosin-V, and is similarly enriched for synaptic vesicle proteins. As demonstrated by immunoelectron microscopy, myosin-V associates with 30–40% of the vesicles in this population. Although a majority of myosin-V-associated vesicles also label with the synaptic vesicle marker protein, SV2, less than half of the total SV2-positive vesicles label with myosin-V. The average size of myosin-V/SV2 double-labeled vesicles (90+/−45 nm) is larger than vesicles that label only with SV2 antibodies (60+/−30 nm). To determine if these vesicles are capable of actin-based transport, we used an in vitro actin filament motility assay in which vesicles were adsorbed to motility assay substrates. As isolated, the myosin-V-associated vesicle fraction was nonmotile. However, vesicles pre-treated with ice-cold 0.1% Triton X-100 supported actin filament motility at rates comparable to those on purified myosin-V. This dilute detergent treatment did not disrupt vesicle integrity. Furthermore, while this treatment removed over 80% of the total vesicle proteins, myosin-V remained tightly vesicle-associated. Finally, function-blocking antibodies against the myosin-V motor domain completely inhibited motility on these substrates. These studies provide direct evidence that vesicle-associated myosin-V is capable of actin transport, and suggest that the activity of myosin-V may be regulated by proteins or lipids on the vesicle surface.

Subcellular localization of myosin V in nerve growth cones and outgrowth from dilute-lethal neurons

Myosin V-null mice (dilute-lethal mutants) exhibit apparent neurological defects that worsen from birth until death in the third postnatal week. Although myosin V is enriched in brain, the neuronal function of myosin V is unclear and the underlying cause of the neurological defects in these mice is unknown. To aide in understanding myosin V function, we examined the distribution of myosin V in the rodent superior cervical ganglion (SCG) growth cone, a well characterized neuronal structure in which myosin V is concentrated. Using affinity purified, myosin V-specific antibodies in immunofluorescence and immunoelectron microscopy, we observed that myosin V is concentrated in organelle-rich regions of the growth cone. Myosin V is present on a distinct population of small (50–100 nm) organelles, and on actin filaments and the plasma membrane. Myosin V-associated organelles are present on both microtubules and actin filaments. These results indicate that myosin V may be carried as a passenger on organelles that are transported along microtubules, and that these organelles may also be capable of movement along actin filaments. In addition, we found no abnormalities in outgrowth, morphology, or cytoskeletal organization of SCG growth cones from dilute-lethal mice. These results indicate that myosin V is not necessary for the traction force needed for growth cone locomotion, for organization of the actin cytoskeleton, or for filopodial dynamics.

Particles move along actin filament bundles in nerve growth cones

Organelle movement along actin filaments has been demonstrated in dissociated squid axoplasm [Kurznetsov, S. A., Langford, G.M. & Weiss, D. G. (1992) Nature (London) 356, 722-725 and Bearer, E.L., DeGiorgis, J.A., Bodner, R.A., Kao, A.W. & Reese, T.S. (1993) Proc. Natl. Acad. Sci. USA 90, 11252-11256] but has not been shown to occur in intact neurons. Here we demonstrate that intracellular transport occurs along actin filament bundles in intact neuronal growth cones. We used video-enhanced differential interference contrast microscopy to observe intracellular transport in superior cervical ganglion neurons cultured under conditions that enhance the visibility of actin bundles within growth cone lamellipodia. Intracellular particles, ranging in size from < 0.5-1.5 microns, moved along linear structures (termed transport bundles) at an average maximum rate of 0.48 micron/sec. After particle movement had been viewed, cultures were preserved by rapid perfusion with chemical fixative. To determine whether particle transport occurred along actin, we then used fluorescence microscopy to correlate this movement with actin and microtubule distributions in the same growth cones. The observed transport bundles colocalized with actin but not with microtubules. The rates of particle movement and the association of moving particles with actin filament bundles suggest that myosins may participate in the transport of organelles (or other materials) in intact neurons.

Solute focusing techniques for bioseparations

The growth of industrial biotechnology has had a major impact on the research and development of both analytical and preparative focusing techniques. Pioneering methods such as isoelectric focusing are being modified to overcome the limitations of batch mode operation, scale up difficulties, high power requirement, and excessive heat generation. present advances in focusing techniques have been made by either overcoming the limitations of standard techniques or by investigating new focusing systems. Here we review the background and history of isoelectric focusing and discuss several new focusing techniques including recycle isoelectric (RIEF), counteracting chromatographic electrophoresis (CACE), and countercurrent gradient chromatography (CGC).

Infectious complications in patients with severe head injury

Mortality and morbidity from head trauma have been substantially reduced by improved prehospital care and aggressive diagnostic and therapeutic management. However, a substantial number of patients will require prolonged periods of hospitalization, intensive care, and ventilator support during their recovery, placing them at risk for infectious complications. Eighty-two such patients were reviewed during a 30-month period at a Level I trauma center. Forty-one patients (50%) developed at least one infectious complication. The most common source was respiratory, occurring in 34 patients relatively early (average, 3.2 days) in their hospital course. The severity of head injury and presence of coexisting thoracic trauma correlated statistically; administration of prophylactic antibiotics and corticosteroids did not in the development of infectious problems. Only three patients died as a result of sepsis, indicating that early recognition and prompt treatment may control the severity of infectious complications.

Early evaluation of cardiac injury by two-dimensional echocardiography in patients suffering blunt chest trauma

The availability of two-dimensional echocardiography as a clinical tool has led to an interest in its applicability, usefulness, and reliability in the evaluation of blunt cardiac trauma. Forty patients who sustained objective evidence of blunt chest trauma were evaluated at our institution using serial ECGs, creatine phosphokinase (CPK) isoenzyme determinations, and two-dimensional echocardiography. Twenty patients (50%) manifested evidence of cardiac injury as demonstrated by abnormal ECGs, elevated CPK isoenzymes, or abnormal echocardiograms. Nine (23%) patients had abnormal echocardiograms with findings of pericardial effusions in four, chamber enlargement in three, and echodense areas of the right ventricle in two. There was no correlation with ECG changes or the presence of CPK isoenzymes. Based on these observations we believe echocardiography can be used as a noninvasive modality to complement other clinical tools in the detection of blunt cardiac injury.

Monoplace hyperbaric oxygen therapy for gas gangrene

Untreated gas gangrene is a fulminating infection that can lead to extensive tissue necrosis and death. Hyperbaric oxygen, when used with antibiotics and surgical debridement, can lead to decreased mortality. Nine patients with gas gangrene proven by positive clostridial cultures have been treated at St Luke's Hospital of Kansas City with a mortality of 11.1%. A case of gas gangrene developing from a perirectal abscess is presented.