Bioactive Hydrogel-Filament Scaffolds for Nerve Repair and Regeneration

The design of novel biomaterials is crucial for the advancement of tissue engineering in nerve regeneration. In this study we developed and evaluated novel biosynthetic scaffolds comprising collagen crosslinked with a terpolymer of poly(N-isopropylacrylamide) (PNiPAAm) as conduits for nerve growth. These collagen-terpolymer (collagen-TERP) scaffolds grafted with the laminin pentapeptide YIGSR were previously used as corneal substitutes in pigs and demonstrated enhanced nerve regeneration compared to allografts. The purpose of this project was to enhance neuronal growth on the collagen-TERP scaffolds through the incorporation of supporting fibers. Neuronal growth on these matrices was assessed in vitro using isolated dorsal root ganglia as a nerve source. Statistical significance was assessed using a one-way ANOVA. The incorporation of fibers into the collagen-TERP scaffolds produced a significant increase in neurite extension (p<0.05). The growth habit of the nerves varied with the type of fiber and included directional growth of the neurites along the surface of certain fiber types. Furthermore, the presence of fibers in the collagen-TERP scaffolds appeared to influence neurite morphology and function; neurites grown on fibers-incorporated collagen-TERP scaffolds expressed higher levels of Na channels compared to the scaffolds without fiber. Overall, our results suggest that incorporation of supporting fibers enhanced neurite outgrowth and that surface properties of the scaffold play an important role in promoting and guiding nerve regeneration. More importantly, this study demonstrates the potential value of tissue engineered collagen-TERP hybrid scaffolds as conduits in peripheral nerve repair.

Sleep patterns and daytime sleepiness in adolescents and young adults with Williams syndrome

BACKGROUND

Sleep disorders are common in individuals with neurodevelopmental disorders and may adversely affect daytime functioning. Children with Williams syndrome have been reported to have disturbed sleep; however, no studies have been performed to determine if these problems continue into adolescence and adulthood.

METHODS

This study examined overnight sleep patterns and daytime sleepiness in 23 adolescents and adults with Williams syndrome age 25.5 (8.0) years [mean (SD)]. Interviewer-administered sleep questionnaires were used to evaluate nighttime sleep behaviours and daytime sleepiness. Wrist actigraphy was used to evaluate sleep patterns.

RESULTS

Although individuals in our sample averaged 9 h in bed at night, daytime sleepiness and measures of sleep disruption were common and comparable to those of other populations with neurodevelopmental disorders. These measures included reduced sleep efficiency [74.4 (7.0)%] with prolonged sleep latency [37.7 (37.3) min], increased wake time after sleep onset [56.1 (17.6) min], and an elevated movement and fragmentation index [14.3 (4.6)].

CONCLUSION

Adolescents and young adults with Williams syndrome were found to be sleepy despite averaging 9 h in bed at night. Implications are discussed for associated causes of sleep disruption and future polysomnographic evaluation.

Lessons learned from a failed multi-institutional randomized controlled study

BACKGROUND/PURPOSE

In 1996, the Surgical Sections of the Children's Cancer Group (CCG) and the Pediatric Oncology Group (POG) received National Cancer Institute funding to conduct a prospective, randomized, controlled, surgeon-directed study to evaluate the role of minimally invasive surgery (MIS) in children with cancer. Because of lack of patient accrual, the study was closed in 1998. The purpose of this study is to evaluate and describe those factors that impacted on study failure to ensure future successful clinical trials.

METHODS

One hundred forty surgeons representing the surgical membership of CCG and POG as well as 111 institutions within CCG and POG were asked to complete a questionnaire about the failed clinical trial. The questionnaire focused on study objectives, organization, and institutional review board (IRB) submission. It also examined the surgeon's ability to perform the minimal access operation, the influence of the pediatric oncologist, and the existence of preconceived biases by surgeons, oncologists, and families. Statistical analysis was performed as appropriate.

RESULTS

Eighty-six of 140 (62%) surgeons responded to the questionnaire. Only 23% of the potential protocols were submitted for IRB approval. Of responding surgeons, 39% were not actively performing MIS when the study opened. A surgeon's support of the study was directly related to when the surgeon received the protocols (P <.001) and whether the participating surgeon was actively participating in MIS (P <.016). The oncologist's knowledge and support of the study affected IRB submission and approval (P <.02) and was influenced by whether MIS was practiced at the institution (P <.05). The majority of responding surgeons believed the experimental question was relevant (P <.05). However, responding surgeons believed that a preconceived bias existed within both their local surgical and oncology communities favoring a particular surgical approach (P <.001), but this bias did not extend to the families (P >.05).

CONCLUSION

The study failed because of lack of accrual for a variety of reasons: failure to submit to the institution's IRB, lack of surgical expertise with MIS procedures, and preconceived surgeon bias toward either an endoscopic or traditional open approach.

MRI imaging of fetal neck masses with airway compromise: utility in delivery planning

We present two cases of fetal neck masses that were initially diagnosed by ultrasound and further evaluated with prenatal MRI. MRI findings aided in further delineating the neck masses, increasing confidence in the final diagnosis (cervical teratoma and cystic hygroma). With the fetal airway typically filled with fluid that is of high signal on T2-weighted sequences, MRI images in three planes could identify whether the fetal larynx and trachea were partially or completely compressed by the neck tumor. This information was particularly useful in determining if a controlled delivery such as ex utero intrapartum treatment (EXIT) was necessary and aided the surgeons in planning their approach to establishing airway control in the delivery room.

The use of a bioactive skin substitute decreases length of stay for pediatric burn patients

BACKGROUND

To optimize burn care for children, the authors introduced a protocol incorporating the use of a bioactive skin substitute, TransCyte (Advanced Tissue Sciences, La Jolla, CA). This study was designed to determine whether this management plan was safe, efficacious, and decreased hospital inpatient length of stay (LOS) compared with conventional burn management in children.

METHODS

All pediatric burns greater than 7% total body surface area (TBSA) that occurred after October 1999 underwent wound closure with TransCyte (n = 20). These cases were compared with the previous 20 consecutive burn cases greater than 7% TBSA that received standard therapy. Standard therapy consisted of application of antimicrobial ointments and hydrodebridement. The following information was obtained: burn mechanism, age, size of burn, requirement of autograft, and LOS. Data were analyzed using the student's t test.

RESULTS

Data for age, percent TBSA burn and LOS are reported as means +/- SEM. The children who received standard therapy were 2.99 +/- 0.7 years compared with those receiving TransCyte were 3.1 +/- 0.8 years. There was no difference between the treatment groups with regard to percent TBSA burn: standard therapy, 14.3 +/- 1.4% TBSA versus TransCyte, 12.7 +/- 1.3% TBSA. There was no difference in the type of burns in each group, the majority were liquid scald type, 70% in the standard therapy group versus 90% in the TransCyte group. Only 1 child in the TransCyte group required autografting (5%) compared with 7 children in the standard therapy group (35%). Children treated with TransCyte had a statistically 6 significant decreaed LOS compared with those receiving standard therapy, 5.9 +/- 0.9 days versus 13.8 +/- 2.2 days, respectively (P =.002).

CONCLUSIONS

This is the first study using TransCyte in children. The authors found that this protocol of burn care was safe, effective, and significantly reduced the LOS. This new approach to pediatric burn care is effective and improves the quality of care for children with burns.

When appendicitis is suspected in children

Acute appendicitis is the most common condition requiring emergent abdominal surgery in childhood. The clinical diagnosis of acute appendicitis is often not straightforward because approximately one-third of children with the condition have atypical clinical findings. The delayed diagnosis of this condition has serious consequences, including appendiceal perforation, abscess formation, peritonitis, sepsis, bowel obstruction, and death. Cross-sectional imaging with ultrasonography (US) and computed tomography (CT) have proved useful for the evaluation of suspected acute appendicitis. There has been a great deal of variability in the utilization of these modalities for such diagnosis in the pediatric population. The principal advantages of US are its lower cost, lack of ionizing radiation, and ability to assess vascularity through color Doppler techniques and to provide dynamic information through graded compression. The principal advantages of CT include less operator dependency than US, as reflected by a higher diagnostic accuracy, and enhanced delineation of disease extent in a perforated appendix.

When appendicitis is suspected in children

Acute appendicitis is the most common condition requiring emergent abdominal surgery in childhood. The clinical diagnosis of acute appendicitis is often not straightforward because approximately one-third of children with the condition have atypical clinical findings. The delayed diagnosis of this condition has serious consequences, including appendiceal perforation, abscess formation, peritonitis, sepsis, bowel obstruction, and death. Cross-sectional imaging with ultrasonography (US) and computed tomography (CT) have proved useful for the evaluation of suspected acute appendicitis. There has been a great deal of variability in the utilization of these modalities for such diagnosis in the pediatric population. The principal advantages of US are its lower cost, lack of ionizing radiation, and ability to assess vascularity through color Doppler techniques and to provide dynamic information through graded compression. The principal advantages of CT include less operator dependency than US, as reflected by a higher diagnostic accuracy, and enhanced delineation of disease extent in a perforated appendix.

Cytoplasmic delivery of a macromolecular fluorescent probe by poly(d, l-lactic-co-glycolic acid) microspheres

A macromolecular fluorescent probe encapsulated in poly(d, l-lactic-co-glycolic acid) (PLGA) microspheres was used as a model for studying cytoplasmic delivery of antigens. We hypothesized that Texas red dextran loaded in PLGA microspheres would be delivered to the cytoplasm and that cytoplasmic delivery would be affected by polymer molecular weight. Cellular localization of the Texas red dextran was investigated at two different molecular weights of PLGA: 6000 and 60,000 g/mol. Intracellular degradation and processing of Texas red dextran-loaded PLGA microspheres by mouse peritoneal macrophages was monitored both in vitro and in vivo for a 7-day period using confocal laser scanning microscopy (CLSM). The results revealed cytoplasmic delivery of the fluorescent probe at both molecular weights of PLGA. Furthermore, the CLSM images showed that both in vitro and in vivo, the kinetics of microsphere degradation and cytoplasmic delivery were more rapid for the 6000 g/mol PLGA microspheres than the 60,000 g/mol PLGA microspheres. Hence, this study provides physical evidence that PLGA microspheres are capable of cytoplasmic delivery and that delivery to the cytosol can be controlled by modifying formulation parameters such as polymer molecular weight.

Differentiated thyroid cancer: clinical characteristics, treatment, and outcome in patients under 21 years of age who present with distant metastases. A report from the Surgical Discipline Committee of the Children's Cancer Group

BACKGROUND/PURPOSE

Young patients with differentiated thyroid cancer typically present with regional lymph node involvement (60% to 80%), and 10% to 20% have distant metastases. This study characterizes the clinical presentation, treatment, and outcome in patients with differentiated thyroid cancer who were less than 21 years of age at diagnosis and who presented with distant parenchymal metastases.

METHODS

A retrospective, multi-institutional data base that included 327 patients in this age group with differentiated thyroid carcinoma was searched for patients who presented with distant metastases, and 83 cases (25%) were found. The median time to first disease progression was 2.4 years (range, 0.1 to 12.4 years) and the overall median follow-up was 10.9 years (range, 1.0 to 42.1 years).

RESULTS

The median age at diagnosis was 14.6 years (range, 6.6 to 20.8 years); 69% were girls and 92% were white. In 12%, there was a history of prior head and neck irradiation, and 10% of these patients had a family history of carcinoma. Preoperative needle biopsies were performed in 25%. Regional lymph nodes were positive in 90%, and extrathyroidal extension occurred in 48%. The site of distant metastases included the lungs in all patients. Total thyroidectomy, subtotal thyroidectomy, lobectomy, and nodule excision was done in 66%, 24%, 3%, and 8% of patients, respectively. There was no residual cervical disease after surgery in 75%, whereas 14% had microscopic and 11% had gross residual. Histopathologic subtypes included papillary-follicular (48%), papillary (42%), and follicular (10%). The median tumor size was 3.0 cm (range, 0.4 to 11.0 cm). In this group, 100% of patients received adjuvant iodine 131I therapy, and the overall survival rate at 10 years was 100%. The progression-free survival rate was 76% at 5 years and 66% at 10 years from diagnosis.

CONCLUSIONS

A significant number of young patients with thyroid cancer present with distant metastases and will require radioiodine therapy. This should be considered when planning the surgical approach because total or subtotal thyroidectomy facilitates 131I imaging and treatment. Although about one third of these patients will experience relapse or disease progression, the overall mortality rate is low.

Delivery of MUC1 mucin peptide by Poly(d,l-lactic-co-glycolic acid) microspheres induces type 1 T helper immune responses

Synthetic peptides corresponding to the variable tandem repeat domain of the cancer-associated antigen MUC1 mucin are candidates for cancer vaccines. In our investigation mice were immunized via subcutaneous injection with poly(d,l-lactic-co-glycolic acid) (PLGA) microspheres containing a MUC1 mucin peptide. It was hypothesized that microencapsulation of the MUC1 mucin peptide would prime for antigen-specific Th1 responses while avoiding the need for traditional adjuvants and carrier proteins. Furthermore, an immunomodulator, monophosphoryl lipid A (MPLA), was incorporated into the peptide-loaded PLGA microspheres based on its ability to enhance Th1 responses. The results revealed T cell specific immune responses. The cytokine secretion profiles of the T cells consisted of high levels of interferon-gamma with undetectable levels of interleukin-4 and interleukin-10. Moreover, incorporation of MPLA in the MUC1 peptide-loaded PLGA microspheres resulted in an increase in interferon-gamma production. The antibody response was negative for IgM and IgG in the absence of MPLA; however, in the presence of MPLA antibody production was negative for IgM with a minimal IgG response consisting of IgG2a, IgG2b, and IgG3. Based on the antibody and cytokine profiles, it was concluded that MUC1 mucin peptide-loaded PLGA microspheres are capable of eliciting specific Th1 responses, which may be enhanced through the use of MPLA.

Ovalbumin peptide encapsulated in poly(d,l lactic-co-glycolic acid) microspheres is capable of inducing a T helper type 1 immune response

An ovalbumin (OVA) peptide, consisting of residues 323-339, was incorporated into poly(d,l lactic-co-glycolic acid) (PLGA) microspheres and administered to mice. It was hypothesized that microencapsulation of the peptide in PLGA microspheres would avoid the need for traditional adjuvants and bias the immune response towards a type 1 T helper (Th1) response. An immunomodulator, monophosphoryl lipid A (MPLA), was incorporated into the microspheres to determine its efficacy in enhancing a Th1 response. The specificity of the immune response was determined using a T cell proliferation assay. The type of T helper response was determined by analysis of the cytokine secretion profiles of the proliferating T cells. Following s.c. immunization, the results revealed a T cell-specific immune response for the encapsulated OVA peptide both with and without MPLA. The cytokine profiles revealed high levels of IFN-gamma with very low levels of IL-4 and IL-10, suggesting a Th1 response. Furthermore, incorporation of MPLA in the peptide loaded PLGA microspheres resulted in an increase in the production of IFN-gamma. Hence, peptide-loaded PLGA microspheres are capable of eliciting a specific Th1 immune response, which may be further enhanced in the presence MPLA.

Differentiated thyroid cancer: determinants of disease progression in patients <21 years of age at diagnosis: a report from the Surgical Discipline Committee of the Children's Cancer Group

OBJECTIVE

This study was done to define the extent of disease and evaluate the effect of staging and treatment variables on progression-free survival in patients with differentiated thyroid carcinoma who were less than 21 years of age at diagnosis.

SUMMARY BACKGROUND DATA

Differentiated thyroid cancer in young patients is associated with early regional lymph node involvement and distant parenchymal metastases. Despite this, the overall long-term survival rate is greater than 90%, which suggests that biologic rather than treatment factors have a greater effect on outcome.

METHODS

Variables analyzed for their impact on progression-free survival in a multi-institutional cohort of 329 patients included age, antecedent thyroid irradiation, extrathyroidal tumor extension, size, nodal involvement, distant metastases, technique of thyroid surgery and lymphatic dissection, initial treatment with 131Iodine, residual cervical disease, and histopathologic subtype. Surgical complications were correlated with the specific procedures completed on the thyroid gland or cervical lymphatics.

RESULTS

The overall progression-free survival rate was 67% (95%, CI: 61%-73%) at 10 years with 2 disease-related deaths. Regional lymph node and distant metastases were present in 74% and 25% of patients, respectively. Progression-free survival was less in younger patients (p = 0.009) and those with residual cervical disease after thyroid surgery (p = 0.001). Permanent hypocalcemia was more frequent after total or subtotal thyroidectomy (p = 0.001) while wound complications increased after radical neck dissections (p < 0.00001).

CONCLUSIONS

The progression-free survival rate was better after a complete resection and in older patients. Progression-free survival rate was the same after lobectomy or more extensive thyroid procedures, but comparison was confounded by the increased use of total or subtotal thyroidectomy in patients with advanced disease. The risk of permanent hypocalcemia increased when total or subtotal thyroidectomy was done. Thyroid lobectomy alone may be appropriate for patients with small localized lesions while total or subtotal thyroidectomy should be considered for more extensive tumors.

The management of choledocholithiasis in children in the era of laparoscopic cholecystectomy

Although laparoscopic cholecystectomy has become the procedure of choice for gallbladder removal in children, the treatment of children who have choledocholithiasis remains unclear. For adults who have suspected choledocholithiasis, preoperative endoscopic retrograde cholangiopancreatography (ERCP) is a well-described and effective approach, however, its use for common bile duct stones in children has not been defined. The authors reviewed the records of 131 consecutive children undergoing laparoscopic cholecystectomy on two surgical services to define the efficacy of ERCP followed by laparoscopic cholecystectomy in managing choledocholithiasis in children. Fourteen children were suspected of having common duct stones noted on preoperative ultrasound scan and laboratory data. At ERCP, six children had no stones visualized; eight had stones and underwent stone extraction and sphincter dilation or sphincterotomy. All 14 underwent laparoscopic cholecystectomy a mean of 3.8 days after ERCP. None of the 14 had evidence of retained stones. Only one of 117 children undergoing primary laparoscopic cholecystectomy had unsuspected common bile duct stones and was treated with laparoscopic common bile duct exploration and stone removal. A management plan incorporating ERCP followed by early laparoscopic cholecystectomy is a safe and effective strategy for children who have choledocholithiasis.

Hepatic tumors in children

Although there is broad consensus that complete resection is the cornerstone of successful management of hepatic malignancies in children, the optimal timing and integration of surgery and chemotherapy remain controversial. Excellent cure rates have been achieved with complete resection followed by multiagent chemotherapy for hepatoblastoma. Future studies are directed toward the identification of "poor risk" patients with protocols designed to improve survival for children with advanced disease and with hepatocellular carcinoma. A multidisciplinary team approach to the care of children with hepatic malignancies using the latest guidelines from clinical trials offers the best opportunity for successful outcomes.

Video-assisted thoracic surgery (VATS) for children with pulmonary metastases from osteosarcoma

BACKGROUND

Video-assisted thoracic surgery (VATS) may complement open thoracotomy in children with osteosarcoma requiring pulmonary metastasectomy.

METHODS

The records of children with metastatic pulmonary osteosarcoma considered for initial VATS intervention (n = 9) were reviewed.

RESULTS

Two children did not have VATS exploration: one child with multiple bilateral nodules and another child with a deep parenchymal nodule. VATS provided diagnostic biopsy material in all cases when used (n = 7). Two children had benign inflammatory lesions; four children had VATS-directed wedge resections of solitary malignant lesions; and one child had VATS biopsy of diffuse parenchymal and pleural pulmonary disease not amenable to resection. The mean operative time and hospital length of stay were 1.78 +/- 0.54 h and 3.5 +/- 1.8 days, respectively. There were two complications of VATS: bleeding in a child, requiring a transfusion, and a latent pneumothorax in a patient after removal of the chest tube.

CONCLUSION

VATS is safe, serves as an excellent diagnostic modality, complements the open thoracotomy, and may enable the surgeon to avoid more extensive procedures in selected cases.

Seeding of vascular grafts with genetically modified endothelial cells. Secretion of recombinant TPA results in decreased seeded cell retention in vitro and in vivo

BACKGROUND

Seeding of small-diameter vascular grafts with endothelial cells (ECs) genetically engineered to secrete fibrinolytic or antithrombotic proteins offers the potential to improve graft patency rates.

METHODS AND RESULTS

Sheep venous ECs were transduced with a retroviral vector encoding human tissue plasminogen activator (TPA). The ECs were seeded onto 4-mm-ID synthetic (Dacron) grafts. Retention of the seeded ECs was measured 2 hours after placement of the seeded grafts both in vitro in a nonpulsatile flow system and in vivo (in sheep) as femoral and carotid interposition grafts. On exposure to flow in vitro, ECs transduced with TPA were retained at a significantly lower rate (median, 67%) than either untransduced ECs (81%) or ECs transduced with a control retroviral vector producing beta-galactosidase (beta-Gal) (80%) (P < .05 for TPA versus either control). On implantation in vivo, ECs transduced with TPA were retained at a very low rate (median, 0%), significantly less than the retention of ECs transduced with the beta-Gal vector (32%; P < .00001). Decreased in vivo retention of ECs transduced with TPA correlated modestly with increased in vitro cellular passage level (r2 = .48; P < .0001) but not with in vivo blood flow rate (P = .45). Addition of the protease inhibitor aprotinin to the cell culture and graft perfusion media resulted in a significant (P < .05) increase in in vitro retention of ECs transduced with TPA.

CONCLUSIONS

Increased TPA expression significantly decreases seeded EC adherence in vitro and in vivo. Gene therapy strategies for decreasing graft thrombosis may require expression of antithrombotic molecules that lack proteolytic activity.

Ultrasonography as an adjunct in the diagnosis of acute appendicitis: a 4-year experience

This study was designed to evaluate the sensitivity and specificity of abdominal ultrasonography as a diagnostic modality in a large series of children who presented with possible appendicitis. From August 1990 to July 1994, 452 children (203 boys, 249 girls) with an average age of 11 years (range, 1 to 20 years) underwent graded compression ultrasonography of the right lower quadrant of the abdomen for the evaluation of possible appendicitis. In the first 18 months of the study all patients with the possible diagnosis of appendicitis (group I; 180 patients) had abdominal ultrasonography after members of the surgical team evaluated and documented their findings in the medical record. In the second study period (30 months), abdominal ultrasonography was recommended only when the clinical diagnosis of acute appendicitis was equivocal (group II; 272 patients). Abdominal ultrasonography was performed using the graded compression technique with a 5.0-MHz linear array transducer. A positive ultrasound study for appendicitis was defined as the presence of an enlarged noncompressible appendix with an outer wall to outer wall diameter of greater than 6 mm, the presence of a complex mass, or the presence of an appendicolith. The sonographic data were correlated with surgical and pathological findings. Appendicitis was confirmed in 112 of the 452 cases. In 17 of these, the appendix was perforated. In the overall group of 452 children, abdominal ultrasonography had a sensitivity of 90%, specificity of 96%, and accuracy of 95%. There was no significant morbidity in the 11 patients with a false-negative study result. All 11 patients had an uncomplicated appendectomy. There were 11 false-positive results; 10 of these patients had a negative laparotomy result (negative laparatomy rate, 8.9%). For the two groups, the sensitivity and specificity of ultrasonography in the diagnosis of appendicitis were equivalent (group 1: 88% sensitivity, 96% specificity; group 2: 92% sensitivity, 97% specificity). On the basis of the high sensitivity and specificity rates, ultrasonography of the appendix can be a useful adjunct to standard examination in the diagnosis of acute appendicitis.

Adenovirus-mediated gene transfer into normal rabbit arteries results in prolonged vascular cell activation, inflammation, and neointimal hyperplasia

Adenovirus vectors are capable of high efficiency in vivo arterial gene transfer, and are currently in use as therapeutic agents in animal models of vascular disease. However, despite substantial data on the ability of viruses to cause vascular inflammation and proliferation, and the presence in current adenovirus vectors of viral open reading frames that are translated in vivo, no study has examined the effect of adenovirus vectors alone on the arterial phenotype. In a rabbit model of gene transfer into a normal artery, we examined potential vascular cell activation, inflammation, and neointimal proliferation resulting from exposure to replication-defective adenovirus. Exposure of normal arteries to adenovirus vectors resulted in: (a) pronounced infiltration of T cells throughout the artery wall; (b) upregulation of intercellular adhesion molecule-1 and vascular cell adhesion molecule-1 in arterial smooth muscle cells; (c) neointimal hyperplasia. These findings were present both 10 and 30 d after gene transfer, with no evidence of a decline in severity over time. Adenovirus vectors have pleiotropic effects on the arterial wall and cause significant pathology. Interpretation of experimental protocols that use adenovirus vectors to address either biological or therapeutic issues should take these observations into account. These observations should also prompt the design of more inert gene transfer vectors.

Endothelium-specific in vivo gene transfer

Targeted expression of genetic material within the vascular endothelium is potentially a powerful tool for the investigation of endothelial cell (EC) biology. We developed, optimized, and characterized an efficient somatic transgenic model of EC-specific gene transfer. Rat carotid arteries were infused with adenovirus expressing a beta-galactosidase (beta-gal) gene. The level and cell-type specificity of recombinant gene expression were measured by assaying beta-gal activity in vessel extracts and by counting transduced cells in histological sections. Toxicity was evaluated by counting total ECs (3 days) and by measuring neointimal formation (14 days). Effects of transduction on the proliferation of vascular cells were measured with bromodeoxyuridine and [3H]thymidine. Maximum recombinant gene expression resulted from infusion of 1 x 10(10) to 1 x 10(11) plaque-forming units (pfu) per milliliter; approximately 35% of luminal ECs were transduced. A high degree of EC specificity (90% to 98% of total transduced cells) was maintained over this range of virus concentrations. More highly concentrated virus resulted in loss of beta-gal expression and a large decrease in luminal EC number (97% decrease, P < .001). Gene transfer at 4 x 10(10) pfu/mL was efficient, preserved EC integrity, and caused minimal neointimal formation. After gene transfer, there were early (3-day) increases in both EC and smooth muscle cell proliferation. At 14 days, only EC proliferation remained elevated (18% versus 1.4% in vehicle-infused arteries, P = .005). This animal model permits efficient highly EC-specific gene transfer. Vascular toxicity is minimal, although the EC proliferative index is elevated. This model will be useful in experiments that elucidate the biological role of EC gene products and define pathways of EC gene regulation and signal transduction in vivo.

Minimally invasive surgery in children with cancer

BACKGROUND

The safety and efficacy of minimally invasive oncologic procedures in children have not been well defined and only limited anecdotal experience has been published.

METHODS

A retrospective review of all patients undergoing either a laparoscopic or thoracoscopic procedure at Childrens Cancer Group institutions between December 1, 1991, and October 1, 1993, was performed.

RESULTS

Eighty-five children underwent 88 minimally invasive surgical procedures as part of the evaluation or treatment for cancer at 15 participating centers. In 25 patients, laparoscopy was performed and 60 patients underwent 63 thoracoscopic operations. Tissue biopsies were taken in 67 cases and diagnostic material was obtained in 99% of the biopsies. Seven complications occurred, all within the thoracoscopic group. These included conversion of six operations to an open procedure. One patient developed atelectasis postoperatively.

CONCLUSIONS

In pediatric patients with suspected cancer, laparoscopy was highly accurate with minimal morbidity; thoracoscopy was nearly as efficient with slightly higher morbidity. Both modalities are useful for assessment of resectability, for staging purposes, and for evaluation of recurrent or metastatic disease.

In vivo gene transfer into injured carotid arteries. Optimization and evaluation of acute toxicity

BACKGROUND

Adenoviral vectors are very attractive agents for use in in vivo arterial gene transfer. In a previous study, we demonstrated high-efficiency adenovirus-mediated gene transfer into medial smooth muscle cells of balloon-injured rat carotid arteries. We now further characterize this system by investigating the reproducibility of recombinant gene expression, the presence of acute adenovirus-associated toxicity in the vessel wall, and the optimal virus concentration for transduction.

METHODS AND RESULTS

Balloon-injured rat carotid arteries were incubated with (1) an adenovirus expressing a beta-galactosidase gene (Av1LacZ4), (2) a related adenovirus without the recombinant gene (Addl312), or (3) control solutions. Recombinant gene expression was determined 3 days after gene transfer by measurement of beta-galactosidase activity in vessel extracts and by counting of smooth muscle cells in microscopic sections that were histochemically stained to detect recombinant beta-galactosidase activity. Adenovirus-associated toxicity was assessed in microscopic cross sections by counting of total smooth muscle cell nuclei in the media (to identify cell loss) and characterization of medial cellular infiltrates with histochemical stains for specific inflammatory cells (neutrophils, lymphocytes, macrophages, and monocytes). Maximum recombinant gene expression after incubation with Av1LacZ4 was produced by virus concentrations ranging from 2 x 10(10) to 5 x 10(10) plaque-forming units (pfu)/mL. Surprisingly, use of a higher concentration of Av1LacZ4 virus (1 x 10(11) pfu/mL) resulted in loss of recombinant gene expression. In addition, infusion of either Av1LacZ4 or Addl312 at 1 x 10(11) pfu/mL resulted in statistically significant decreases in medial smooth muscle cell number (53% decrease, P < 0.01 for Av1LacZ4; 39% decrease, P < .05 for Addl312) compared with vessels infused with control solution. This decrease in smooth muscle cell number was not present after the infusion of virus at lower concentrations. The number of neutrophils in vessel cross sections was significantly increased (fivefold; P < .05) after infusion of Av1LacZ4 at 1 x 10(11) pfu/mL compared with vessels infused with control solution. Lymphocytes, macrophages, and monocytes were present only in low numbers in all vessel cross sections and were not increased consequent to adenovirus infusion.

CONCLUSIONS

This model of focal in vivo adenovirus-mediated gene transfer into the media of injured arteries is highly reproducible and allows high-level recombinant gene expression over a fairly narrow range of virus concentrations. Acute adenovirus-associated tissue toxicity, as demonstrated by medial smooth muscle cell loss and neutrophilic infiltrates, places an upper limit on virus concentration and associated recombinant gene expression and suggests the presence of a "window" of virus concentration in which either therapeutic or biological effects of recombinant genes can be studied in the absence of associated acute toxicity.

In vivo adenovirus-mediated gene transfer via the pulmonary artery of rats

Gene transfer into the pulmonary vasculature has the potential to be a powerful technique for both investigation of pulmonary pathophysiology and development of genetic therapies for pulmonary vascular disease. To evaluate the potential for in vivo pulmonary arterial gene transfer, we infused adenoviral vectors into the left pulmonary artery of Sprague-Dawley and cotton rats. Access to the left pulmonary artery was obtained by a percutaneous transcatheter approach or through thoracotomy and pulmonary arteriotomy. With the thoracotomy approach, both pulmonary arterial inflow and pulmonary venous outflow were occluded during vector influsion and throughout a subsequent 20-minute dwell period. The success of gene transfer was assessed by staining for evidence of recombinant gene expression in lungs excised at time points ranging from 48 to 72 hours after virus infusion. With the thoracotomy technique, pulmonary gene transfer was successful in 15% of surviving Sprague-Dawley rats and 30% of surviving cotton rats. Percutaneous catheter-based pulmonary gene transfer was not successful. In rats with pulmonary gene transfer, 1% to 8% of total left lung cells expressed the recombinant gene. Recombinant gene expression was found in endothelial cells (0.2% to 18% of total transduced cells), smooth muscle cells (0% to 3%), macrophages (1% to 7%), airway epithelial cells (2% to 50%), and alveolar epithelial cells (38% to 94%). Investigation of the low rate of successful gene transfer in individual animals suggested that insufficient physical contact between the virions and pulmonary cells was the most likely cause. In vivo gene transfer into the rat pulmonary vasculature can be accomplished with adenovirus vectors.(ABSTRACT TRUNCATED AT 250 WORDS)

A proposed classification of vaginal anomalies and their surgical correction

A classification of vaginal anomalies has been derived, which permits logical operative decisions. This tool allows the assignment of increasingly involved reconstructive operations to progressively more complex vaginal anatomies. The outcome of this approach in 49 vaginal reconstructions performed in 36 patients over a 25-year period has been analyzed. The cause was found to be congenital adrenal hyperplasia in 21 patients, gonadal dysgenesis in four, and cloaca in two; nine children had other causes. Based on the following anatomic classification and the authors' clinical experience, the following approaches to reconstruction can be recommended. Eight infants with labial fusion (type I) underwent simple introitoplasty. Fourteen patients with distal urogenital sinus (type II) underwent flap vaginoplasty using labioscrotal tissue and/or a posteriorly based flap. Pull-through vaginoplasty was used in 10 children with distal vaginal atresia and proximal urethrovaginal fistula (type III). Four patients with absence of the vagina (type IV) required segmental colon vaginoplasty. Thirteen revisions have been required in nine patients thus far. The follow-up period is 1 to 17 years, and despite the need for reoperation, all but two patients have excellent or satisfactory results based on anatomic and functional considerations. The choice for and timing of vaginal reconstruction rests on precise anatomic evaluation. The complexity of vaginal reconstruction in the growing child and the essentiality of psychosocial adjustment to appropriate sexual identity and function mandate long-term comprehensive follow-up. Optimal care for each patient requires experience and continuity to take the child through diagnosis, surgical reconstruction, stressful adolescence, and into adulthood with full attention to anatomic, physiological, and psychological support.

Experience with abdominal wall closure for patients with congenital diaphragmatic hernia repaired on ECMO

Congenital diaphragmatic hernia (CDH) and its attendant lack of abdominal domain can create major technical challenges with respect to diaphragmatic and abdominal wall reconstruction, especially in seriously ill infants who require extracorporeal membrane oxygenation (ECMO). The authors reviewed the medical records of all infants with CDH repaired on ECMO at their institution (group 1, 15 patients), and compared them with infants having CDH repair before ECMO (group 2, 20 patients) and with those who had CDH repair but did not require ECMO (group 3, 15 patients). Thirty-seven of 50 patients survived (74%): 10 in group 1, 12 in group 2, and all 15 in group 3. There was a statistically significant difference (P < .001) with respect to the requirement of a polytetrafluoroethylene (PTFE) diaphragmatic patch for patients in group 1 versus those in both groups 2 and 3. There was also a significant difference in the number of patients in whom the abdomen could not be closed (P < .001 for group 1 v groups 2 and 3). Infants who require ECMO before CDH repair are more likely to have large diaphragmatic defects that require prosthetic reconstruction, and abdominal wall closure problems resulting from loss of abdominal domain, which further complicate the management of the physiological derangements from pulmonary hypoplasia and persistent pulmonary hypertension.

Optimization of recombinant t-PA secretion from seeded vascular grafts

Seeding of vascular grafts with genetically engineered endothelial cells (EC) secreting anticoagulant or fibrinolytic agents offers a potential means of improving patency rates. Prior to the initiation of in vivo studies, we examined cell retention and tissue plasminogen activator (t-PA) secretion from small-diameter synthetic graft segments seeded with sheep venous EC genetically engineered to secrete human t-PA. Following retroviral-mediated gene transfer, EC were seeded at varying densities onto 4-mm-diameter synthetic graft segments of different composition, achieving confluent coverage of all materials. t-PA production from seeded grafts was evaluated under both static conditions and after flow exposure, for up to 3 days after seeding. t-PA secretion varied directly with increasing seeding density for all graft types, reaching a maximum of 20 ng/cm2/24 hr. t-PA secretion correlated highly with the number of seeded cells as determined by measurement of DNA from lysates of seeded grafts (r2 = 0.90, P < 0.0001). For all graft types tested, approximately 50% of seeded cells were retained after exposure to flow in vitro. Retained EC remained viable as determined by t-PA secretion. The rate of t-PA secretion from collagen-impregnated Dacron grafts was higher than that obtained with other materials both under static conditions and after flow exposure. This higher rate was most likely due to the higher surface area presented by the Dacron grafts. These data demonstrate that small-diameter prosthetic graft materials can be coated with a layer of EC that (i) remains metabolically active and capable of secreting a fibrinolytic agent, and (ii) remains adherent to the graft surface after exposure to flow. These experiments provide a foundation for in vivo studies in which grafts are seeded with EC genetically engineered to increase local fibrinolysis.

Adenoviral vector-mediated gene transfer into sheep arteries using a double-balloon catheter

The potential for catheter-based in vivo delivery of genetic material to the arterial wall is incompletely explored. We evaluated the level of recombinant protein production as well as the anatomic distribution and duration of gene expression following adenoviral vector-mediated gene transfer into sheep arteries via a double balloon catheter. Catheters were positioned in the carotid or femoral arteries of 20 sheep via a combined percutaneous and surgical approach, and virions infused over a 30-min period. Three days later, recombinant gene expression was identified in approximately 30% (range 0-80%) of the luminal endothelial cells within the targeted area of the artery. Persistent recombinant protein expression was identified histochemically for up to 4 weeks, although the number of positive cells decreased steadily. High levels of both beta-galactosidase (beta-Gal) activity and protein (mean 20 mU and 44 ng per vessel) were measured in vessel extracts 3 days after gene transfer, again decreasing significantly over a 4-week period. Transgene expression was limited almost entirely to the intima and adventitia; adventitial gene transfer occurred virtually exclusively along the vasa vasorum. In comparison to previous studies of catheter-based gene transfer, adenoviral vectors delivered by double balloon catheter resulted in a particularly high efficiency of endothelial cell gene transfer. The efficiency and amount of recombinant gene expression achieved in this study suggest that catheter-based gene delivery may eventually be applicable to the treatment of focal human arterial disease.

Diamond flap anoplasty in infants and children with an intractable anal stricture

After posterior sagittal anorectoplasty for imperforate anus a prolonged course of anal dilatations is necessary until the scar softens. Although rare, severe stricture after this procedure is difficult to resolve. Y-V plasty is not entirely satisfactory because the pedicle advanced into the anus has some tension, which tends to retract producing recurrent stricture. The authors performed a diamond-shaped island anoplasty in eight children with postoperative and strictures (one after an unsuccessful Y-V plasty), with prompt resolution of the stricture in five. The island flap anoplasty consists of a diamond-shaped flap of skin formed laterally, with complete separation of skin and subcutaneous attachments around the periphery of the flap. The skin island is supplied with blood from the deep tissue. An incision is made through the scarred anal ring and into the mucosa, a distance of half the length of the diamond, which is then advanced into the mucosal defect. The defect lateral to the advanced flap is sutured closed. The island of skin descends naturally into the anus, under no tension. The procedure can be performed simultaneously in the 3 o'clock and 9 o'clock positions, and can later be repeated anteriorly and posteriorly, although this has not been necessary. Two of the eight children have required no dilatation postoperatively, a distinct advantage in the 4-year-old patient. One segment in one child sloughed, resulting in repeat stricture that is responding to dilatation. The other seven children are doing well with their colostomies closed.

Rhabdomyosarcoma of the clitoris

Genitourinary rhabdomyosarcoma in females usually originates in the vagina or uterus, but rarely the vulva. The authors present a case of rhabdomyosarcoma originating in the clitoris. A 4-year-old with an alveolar rhabdomyosarcoma of the clitoris was treated with radical clitorectomy, radiation, and chemotherapy. Follow-up at 3 years showed no active disease.

Insulin measurement and preparation among diabetic patients at a county hospital

The investigator conducted a pilot study of 52 insulin-using adult diabetic patients at an urban county hospital in the Southeast. The purpose was to assess the ability of adult diabetic patients to measure and prepare insulin in a syringe. Results indicated that patients exhibited important deficits in their ability to prepare and measure insulin in a syringe. In addition, many subjects had difficulty with basic arithmetic involving addition and were unable to calculate their total amount of regular and long-acting (NPH) insulin. Other interesting findings were: 1) 48% did not roll the NPH vial to mix it properly, 2) 71% of the sample population did not eliminate air bubbles from the syringe, and 3) 23% of the sample population contaminated the regular insulin with the NPH insulin. Factors found to be associated with patients' insulin preparation tasks were age, arthritis of the hands, visual acuity, and education.

Anatomic barriers influence the distribution of in vivo gene transfer into the arterial wall. Modeling with microscopic tracer particles and verification with a recombinant adenoviral vector

We evaluated the extent to which anatomic barriers to vector penetration might influence the distribution of successful in vivo gene transfer into the normal arterial wall. A double-balloon catheter technique with infusion pressures of 100 to 400 mm Hg was used to infuse microscopic tracer particles of the size range of liposomes and viral vectors into normal elastic arteries of sheep. Localization of the tracer particles in tissue sections by light, fluorescence, and electron microscopy suggested that vector-sized particles were delivered to the intima by direct infusion and to the adventitia via the arterial vasa vasorum. Particles were virtually absent from the arterial media. To test the predictions made from the particle studies, we repeated the infusion protocol with high-titer adenoviral vectors. Gene transfer occurred at high levels in the intima and along the adventitial vasa vasorum but again was virtually absent within the media. The ability of medial smooth muscle cells to be transduced was established in separate experiments with a high-pressure (5 atm) porous balloon infusion catheter. We conclude that (1) the anatomy of the normal elastic arterial wall imposes significant limitations on the penetration of particles in the size range of most gene-transfer vectors and (2) the distribution of in vivo gene transfer with adenoviral vectors is correctly predicted by the distribution of inert tracer particles. These findings have important implications for the design of arterial gene-transfer and gene-therapy protocols.

Protocols for college health nurses: alive and well in the 1990s

This article seeks to assist college health nurses in developing appropriate protocols for patient care. In addition, the authors outline factors influencing protocol content, design, and development and describe steps in creating individualized protocols by practice setting. To provide college health nurses with a basic understanding of protocols, the authors offer definitions and examples of appropriate and inappropriate use, and show how protocols can influence the delivery of patient care. Although protocols may provide college health nurses with directives for managing specific health problems, they require a sophisticated level of judgment and skill in their implementation.

Giving up: shelter experiences of battered women

Within the last decade intrafamilial violence has been identified as a major health and social problem. Women in particular are at high risk for battering and often seek refuge in shelters. Empirical evidence is required regarding the experiences of battered women who use these shelters. Therefore, we collected qualitative data from interviews with seven battered women and by observation in ten group counseling sessions at a shelter in the Southeast. Using grounded theory methodology, the core concept that emerged was "giving up." Supporting concepts were helplessness and fear of the unknown. The participants found it easier to give up and return to the abusive relationship than to seek alternatives.

The current management of thyroid tumors in childhood

Thyroid cancer is a rare but intriguing malignancy when it occurs in childhood and adolescence. Although it often presents at a more advanced stage than similar adult thyroid tumors, the biologic behavior is more benign, accounting for improved survival. Therefore, pediatricians and surgeons have debated the wisdom of aggressive versus conservative surgical approaches. Although the final answers have not been achieved it has become increasingly clear that radical surgical approaches may be unnecessary. Further investigation of the tumor cell biology, genetics, and molecular biology of thyroid tumors may allow prospective classification of children so that the best operative and adjuvant management can be selected for each individual.

Visualization of enlarged mesenteric lymph nodes at US examination. Clinical significance

PURPOSE

To identify conditions associated with enlarged mesenteric lymph nodes in children with acute abdominal pain and determine the ability of US to detect associated abnormalities.

METHODS

Two hundred and fifty children with acute abdominal pain were evaluated for the presence of enlarged mesenteric lymph nodes (AP diameter > 4 mm). Additionally, a reference group of 50 asymptomatic children was also studied for the presence of enlarged mesenteric lymph nodes.

RESULTS

Enlarged mesenteric lymph nodes were noted in 35 (14%) symptomatic children and two (4%) asymptomatic children. A specific diagnosis was established in 16/35 (46%) symptomatic children with mesenteric lymphadenopathy. Acute appendicitis was the most common diagnosis. The discharge diagnosis in the remaining 19 children was abdominal pain or gastroenteritis of unknown origin. US suggested the correct diagnosis in 12/16 (75%) children in whom a definite diagnosis was established. Histopathologic examination of enlarged mesenteric lymph nodes in three patients demonstrated non-specific inflammatory changes.

CONCLUSION

Enlarged mesenteric lymph nodes in children with acute abdominal pain represents a nonspecific finding. Mesenteric lymphadenopathy is associated with a variety of medical and surgical conditions in symptomatic children and is occasionally seen in asymptomatic children. Sonography is useful in establishing a primary diagnosis in these children.

Appendicitis: usefulness of US in diagnosis in a pediatric population

One hundred eighty pediatric patients with suspected appendicitis were prospectively examined with graded compression ultrasonography (US) to assess the sensitivity, specificity, and accuracy of graded compression US in the diagnosis of appendicitis in children and to compare those results with results of clinical assessment in the diagnosis of this disorder. Patients were assigned to one of three groups prior to US based on the clinical level of confidence that appendicitis was present and on the planned management decision. Of 141 patients in the low- and intermediate-clinical risk categories, 20 (14%) had appendicitis: US had a sensitivity of 100%, specificity of 97%, and accuracy of 97% in these two groups. Of 39 patients in the high-clinical risk category, 32 (82%) had appendicitis: US had a sensitivity of 81%, specificity of 86%, and accuracy of 82%. Of 52 patients with surgically proved appendicitis, the initial management decision was to discharge to home or admit for observation and further testing in 18 (35%). Results at US were positive for appendicitis in all 18 patients in the latter two categories.

Molecular characterization of the soybean alcohol dehydrogenase gene family amplified in vitro by the polymerase chain reaction

Soybean (Glycine max) alcohol dehydrogenase (ADH) cDNAs were amplified in vitro from total RNA by the polymerase chain reaction (PCR). The amplification strategy involved first strand cDNA synthesis from anaerobic cotyledon total RNA using an 18-thymidine primer. The second strand cDNA primer was a conserved sequence near the 5' end of known plant ADH transcripts. The PCR products were ligated into a plasmid vector and unique clones were isolated on the basis of size and restriction pattern. Sequence analysis revealed three distinct classes of soybean ADH cDNAs, all of which showed high homology to Adh genes from maize and peas. RNA blot hybridization analyses showed differential expression patterns for these genes. One gene, expressed constitutively in all seedling organs, was inducible by anaerobiosis, one gene was expressed only in anaerobic organs, and the third gene was expressed predominantly in anaerobic roots.

Malignant liver tumors of children

Malignant liver tumors in children are uncommon but have a high mortality. Survival rates have improved with advances in chemotherapy, imaging, tumor biology, and supportive care. However, complete surgical resection is the cornerstone of successful management. Important determinants of outcome are stage, histology, and resectability. A multidisciplinary team approach to the care of pediatric patients with liver tumors using the latest guidelines from clinical trials provides the best opportunity for care.

Low level in vivo gene transfer into the arterial wall through a perforated balloon catheter

BACKGROUND

Gene transfer into the arterial wall may provide a novel therapeutic strategy for the treatment of coronary artery restenosis. Previously described methods for gene transfer into the arterial wall require total vessel occlusion for 30 minutes. We sought to develop a protocol for gene transfer within a more clinically relevant time frame.

METHODS AND RESULTS

We used a perforated balloon (Wolinsky) catheter to inject retroviral vector-containing virions into rabbit aortas in vivo. The virions were injected within 1 minute. Aortas were removed 5-14 days after injection and analyzed for evidence of gene transfer. In initial studies, nine rabbits were injected with a vector expressing the beta-galactosidase gene, and nine rabbits were injected with either non-beta-galactosidase-containing vectors or with a vehicle control. Histochemical staining of aortic tissues revealed blue (positive) cells in eight of nine experimental rabbits and six of nine controls. Because of the lack of specificity of the beta-galactosidase detection system, we adopted a polymerase chain reaction-based protocol in which oligonucleotide primers were used to amplify specific vector-related sequences from aortic tissue extracts. The polymerase chain reaction protocol, calibrated with standards containing known numbers of transduced cells, revealed low amounts of vector-related sequences in six of 12 vector-injected rabbits and in one of 13 controls (p less than 0.03). Comparison with standards indicated that fewer than 100 transduced cells were present in a 2-cm length of the injected aortic tissue.

CONCLUSIONS

Although in vivo gene transfer through an infusion balloon catheter can be accomplished within 1 minute, the therapeutic use of this protocol is limited by the small number of cells that are transduced.

A community health nursing curriculum and Healthy People 2000

The School of Nursing at the University of Alabama at Birmingham recently revised its graduate level community health nursing curriculum based on the priority areas and health objectives in Healthy People 2000. Health priority areas are presented as class topics and provide direction for the students' fieldwork. This paper provides background on the national strategy used to develop the national health objectives, suggestions on how nursing can be at the forefront of influencing the health of the nation, and specifics involved in implementing a community health nursing curriculum using the year 2000 health objectives.

Laparoscopic cholecystectomy in pediatric patients

Laparoscopic cholecystectomy has gained increasing application as an operative approach for adults with gallbladder disease. We assessed the safety and feasibility of this technique in five pediatric patients with symptomatic cholelithiasis, two of whom had sickle cell disease. With several technical modifications, we found that laparoscopic cholecystectomy was safe and effective in children. This technique permitted early discharge with expedient return to full activity.

Quantification of vascular graft seeding by use of computer-assisted image analysis and genetically modified endothelial cells

Current methods for the evaluation of retention of endothelial cells seeded on vascular grafts are limited by the inability to specifically identify and quantitate seeded cells on a long-term basis. To address this problem we developed a method of quantification of graft surface coverage using genetic labeling of endothelial cells combined with computer-assisted image analysis. Rabbit aortic endothelial cells were transduced with a marker gene (lac-Z) and seeded on polytetrafluoroethylene grafts. After histochemical staining in which the genetically labeled cells turn blue, computer-assisted image analysis was used to measure the percentage of graft surface covered by the seeded cells. The utility of the method was evaluated by using it to assess the effect on graft coverage of seeded cell density and by precoating with fibronectin. Quantification of surface area coverage was automated and reproducible both between scans and between observers. Use of this method allowed the determination of a linear correlation between cell density in the seeding suspension and graft coverage (r2 = 0.93, p less than 0.0001). The method also permitted confirmation of the positive contribution of fibronectin coating to graft coverage by seeded cells: 73% coverage coated versus 8% coverage uncoated (p less than 0.0001). The ability of this method to specifically identify genetically marked endothelial cells and their progeny makes it attractive for use in studies targeted at optimization of graft coverage in vivo.

Alkaline gastroesophageal reflux in infants and children

The incidence of alkaline gastroesophageal reflux (GER) was examined in 111 consecutive children referred for evaluation of GER during a 1-year period. The results of 24-hour pH monitoring studies and the medical records were retrospectively evaluated. Acid reflux was defined as occurring whenever the pH was less than 4 and alkaline reflux was defined whenever the pH was greater than 7. The percentage of time that reflux occurred, the number of reflux episodes, the number of episodes greater than 5 minutes, and the longest episode were all recorded. Based on these data, four categories of patients were identified as compared with normal values as determined by Pellegrini et al. When using criteria based on the percentage of time that reflux occurred, the largest group of children with GER was found to reflux acid (50%). However, 27 children (24%) had combined acid and alkaline reflux. Eighteen (16%) had predominantly alkaline reflux. Previously, these 18 children would have been considered as having a low likelihood of reflux by pH criteria. Endoscopic examination showed that pathological evidence of esophagitis occurred in four of the children with pure alkaline reflux. This review shows that symptomatic GER in infants and children may be due to acid or alkaline secretions or a mixture of both. A previously unrecognized cohort exists of children who demonstrate primary alkaline reflux. These patients need to be recognized and may benefit from a therapeutic program specifically designed to control alkaline reflux.

Safety-belt injuries in children with lap-belt ecchymosis: CT findings in 61 patients

We have noted a complex of common injuries in children wearing lap-styled safety belts during vehicular accidents. Sixty-one children who were restrained passengers in motor vehicle crashes had linear ecchymosis across the abdomen and had CT for abdominal trauma. Thirteen children (21%) had a lumbar spine injury, and 14 children (23%) injured a hollow viscus (bowel, 12; bladder, two); five children (8%) had both spine and hollow viscus injuries. Abnormal findings on abdominal CT were recognized retrospectively in three of 13 children with lumbar spinal injury. Lateral radiographs of the spine showed lumbar spinal injury in all cases. Free intraperitoneal air was noted in on three (25%) of 12 children with bowel injury. In eight of those children, CT showed large, unexplained collections of peritoneal fluid. The presence of lap-belt ecchymosis should prompt a careful search for spine, bowel, and bladder injury. Recognition of the limitations of CT diagnosis of these injuries is important to reduce errors in interpretation.

Retroviral vector-mediated in vivo expression of low-density-lipoprotein receptors in the Watanabe heritable hyperlipidemic rabbit

We have achieved in vivo expression of recombinant low-density-lipoprotein (LDL) receptors in the Watanabe heritable hyperlipidemic (WHHL) rabbit, an animal model for the human disease familial hypercholesterolemia. A retroviral vector was constructed containing the human LDL receptor cDNA and was used to stably transduce primary skin fibroblasts from WHHL rabbits. The integrity and function of the introduced LDL receptor was established by immunoprecipitation, by a fluorescent LDL binding assay, and by the ability of the transduced cells to suppress 3-hydroxy-3-methyl-glutaryl-coenzyme A reductase activity in response to exogenous cholesterol. Autologous transduced fibroblasts were reimplanted into donor rabbits; in vivo LDL receptor expression and the survival of the transduced cells were analyzed by immunohistochemistry and by LDL binding assays performed on cells recovered from the implants. LDL receptor-bearing cells could be identified on tissue sections and recovered from implants for up to four weeks. Total and LDL cholesterol levels decreased significantly after implantation of the transduced cells; however, control experiments indicated that the decreases were not mediated through the recombinant LDL receptor. While in vivo stable expression of recombinant LDL receptors in Watanabe rabbits is possible, consequent changes in lipid levels must be interpreted with caution. This system of site-specific in vivo expression of recombinant LDL receptors permits further evaluation of the role of LDL receptor-gene replacement in the therapy of hypercholesterolemia.

Effect of extracorporeal membrane oxygenation on survival of infants with congenital diaphragmatic hernia

To determine the effect of extracorporeal membrane oxygenation (ECMO) on the survival of infants with congenital diaphragmatic hernia, we undertook a retrospective review of 31 infants with congenital diaphragmatic hernia treated at Children's National Medical Center. Infants were categorized by means of the Bohn quadrant analysis to determine the impact of ECMO on infants with congenital diaphragmatic hernia and a "poor prognosis." All infants assigned to the Bohn 100% mortality quadrant required ECMO. The survival rate in this group was 86% (6/7) when assessed preoperatively and 67% (6/9) when assessed postoperatively. Comparison of the change occurring in ventilation index and arterial carbon dioxide pressure demonstrated that after repair the clinical condition of 48% of infants deteriorated, 40% improved, and 12% remained unchanged. Of the 12 infants whose condition was worse after surgery, 11 eventually required ECMO. Our review demonstrates that ECMO improved survival significantly in infants with congenital diaphragmatic hernia who had a "poor prognosis" by the criteria of Bohn et al. We recommend consideration of ECMO for all infants with congenital diaphragmatic hernia for whom maximal medical therapy has failed.

The papillary-cystic neoplasm of the pancreas. An increasingly recognized clinicopathologic entity

The clinical course of the papillary-cystic neoplasm of the pancreas is contrasted with that of the pancreatic ductal adenocarcinoma. The former occurs predominantly in young women, has a low malignant potential, and is highly curable with surgical treatment. Three cases are reported that illustrate the typical clinical features and the indolent nature of the tumor. One case was discovered after blunt abdominal trauma resulted in rupture of the tumor and hemoperitoneum. All cases were treated by pancreatic resection with preservation of the spleen, an important consideration in younger patients. All patients were free of disease at long-term follow-up. Increasing awareness of this tumor has resulted in the reclassification of several tumors and should lead to better recognition by surgeons caring for patients with pancreatic diseases.