Srikumar B. Pillai

Characterization of Cell-Associated and Soluble Forms of Connective Tissue Growth Factor (CTGF) Produced by Fibroblast Cells In Vitro

Connective tissue growth factor (CTGF) is a mitogenic and chemotactic factor for cultured fibroblasts that has been implicated in wound healing, fibrotic disorders and uterine function. Although the primary translational products of the mouse, human and pig CTGF (mCTGF, hCTGF, pCTGF) genes are predicted to be secreted and of approximate M(r) 38,000, 10 kDa biologically active forms of pCTGF have recently been described. In this report, we show that human foreskin fibroblasts (HFFs) and mouse connective tissue fibroblasts contained 2.4 kb CTGF transcripts, stained positively with an anti-CTGF[81-94] peptide antiserum, and produced a 38 kDa protein that was immunoprecipitated by an anti-CTGF[247-260] peptide antiserum. While 38 kDa CTGF was readily detected in cell lysates, it was non- or barely detectable in conditioned medium. 38 kDa CTGF remained cell-associated for at least 5 days after synthesis and was not releasable by treatment of the cells with trypsin, heparin, 1 M NaCl or low pH. Purification of CTGF from human or mouse fibroblast conditioned medium resulted in the isolation of 10-12 kDa CTGF proteins that were heparin-binding, bioactive, and reactive with anti-CTGF[247-260] on Western blots. Whereas 10 kDa CTGF stimulated DNA synthesis in 3T3 cells to the same extent as platelet-derived growth factor (PDGF)-AA, -AB, or -BB, it did not compete with 125I-PDGF-BB for binding to alpha alpha, alpha beta or beta beta PDGF receptors (PDGF-R), did not stimulate tyrosine phosphorylation of PDGF-alpha-R or -beta-R, and was not antagonized by a neutralizing PDGF-R-alpha antiserum. These data show that, in cultured fibroblasts, 38 kDa CTGF is principally cell-associated whereas low mass forms of CTGF are soluble and biologically active. They further demonstrate that, contrary to the previously proposed properties of 38 kDa CTGF, 10 kDa CTGF does not bind to PDGF-R and stimulates Balb/c 3T3 cell mitosis via a PDGF-R-independent mechanism.

Heparin-binding EGF-like growth factor is cytoprotective for intestinal epithelial cells exposed to hypoxia

BACKGROUND During recovery from intestinal ischemic injury, there is rapid growth of intestinal epithelia with regeneration of damaged villi. This study examines the effects of heparin-binding EGF-like growth factor (HB-EGF) on the recovery of intestinal epithelial cells exposed to hypoxia. METHODS The cytoprotective effects of HB-EGF were analyzed by placing IEC-18 cells in an anaerobic chamber with various timed HB-EGF treatments (prehypoxia, posthypoxia, pre- and posthypoxia, and no treatment). After 10 hours of hypoxia, lactate dehydrogenase (LDH) release, actin-filament (structural) integrity, adenosine triphosphate (ATP) levels, and posthypoxia proliferative activity were evaluated. RESULTS LDH analysis showed that HB-EGF exerted a cytoprotective effect during hypoxia. Pretreated cells had a significantly lower death rate during recovery (7.48%) compared with cells with no HB-EGF treatment (22.19%, P < .009). Confocal microscopic structural analysis of posthypoxia cells showed that F-actin structure was maintained in treated cells, whereas nontreated cells showed increased structural deterioration. ATP levels were significantly higher in the HB-EGF-treated cells compared with nontreated cells at 48 hours (P < .05). Finally, HB-EGF-treated cells had a significantly improved proliferative ability compared with nontreated cells during recovery from hypoxia (P < .05). CONCLUSIONS HB-EGF is a mitogenic growth factor for intestinal epithelial cells. Moreover, HB-EGF appears to protect intestinal epithelial cells from hypoxia, in part via maintenance of cytoskeletal structure and ATP stores. Finally, HB-EGF-treated cells also appear to have better proliferative abilities during recovery from hypoxia.

Pediatric testicular problems.

Testicular problems in children may be both congenital and acquired. These problems are often difficult to diagnose and carry significant sequelae if untreated. Early surgical consultation is often needed for correction of the problem. This article reviews the pathophysiology of the most common pediatric testicular abnormalities with emphasis on the diagnostic modalities employed and current treatment alternatives.

Rectal pH measurement in tracking cardiac performance in a hemorrhagic shock model.

OBJECTIVE AND DESIGN We evaluated the utility of rectal mucosal pH measurement for tracking cardiac performance in hemorrhagic shock as compared with gastric tonometry. MATERIALS AND METHODS Hemorrhagic shock was induced in five adult swine to a mean arterial pressure of 45-65 mm Hg. Hypotension was maintained for 30 minutes, resuscitation was accomplished with the shed blood and lactated Ringers solution (3x blood volume). Gastric tonometry, rectal pH, and oxygen transport data were obtained at baseline, 0, and 30 minutes after onset of hypotension and after resuscitation. RESULTS Intramucosal pH readings from gastric tonometry and rectal mucosal pH both showed a significant change from baseline to 0 and 30 minutes after onset of hypotension. Data after resuscitation were found to be statistically the same as baseline values. CONCLUSIONS Rectal mucosal pH tracks cardiac performance as well as does gastric tonometry in hemorrhagic shock without as many limitations.

The childhood air gun: Serious injuries and surgical interventions

Objective Increasingly powerful nonpowder firearms or air guns are frequently given to children as toys. We undertook the present study to evaluate the injuries caused by these firearms, based on the concern that they are capable of inflicting serious trauma. Design Descriptive, retrospective chart review. Setting Urban level I pediatric trauma center. Participants The study included all children with injuries secondary to air guns who were admitted between July 1988 and March 1995. Main outcome measures Type of weapon, circumstances of injury, anatomic location of injury, injury severity, surgeries performed, morbidity. Interventions None. Results There were 42 admissions with a mean hospital stay of seven days (range 1 to 136 days). The average age was 10 years (range 1 to 23 years) with a median age of 11 years. There were 35 boys and 7 girls. Twenty-nine of the 42 injuries were caused by a family member or friend and five were self-inflicted. The mean injury severity score was 83. While there were no fatalities, 21 children (50%) underwent operative procedures for their injuries. Ten of the injuries were potentially lethal, of which seven were due to the “pump” action air gun. Sixteen patients had serious long-term disability as a result of their injuries. Conclusion Air guns can cause a variety of serious injuries, often requiring operative intervention. The long-term morbidity from some of these injuries is significant Both parents and physicians should be aware that nonpowder guns are not toys, but weapons capable of inflicting serious trauma. The evaluation and treatment of air gun injuries should be similar to that currently used for powder weapon injuries. Recommendations for evaluation and treatment are made.

Pediatric airbag injuries: The Ohio experience

BACKGROUND/PURPOSE We sought to determine if properly restrained children, less than 13 years of age, placed in the front passenger seat are at greater risk for trauma from airbag deployment than unrestrained children. METHODS The charts of children treated at any of 3 regional pediatric trauma centers in Ohio were reviewed for airbag injuries sustained in motor vehicle crashes between January 1995 and September 1998. Injury Severity Scores (ISS) were compared with Mann-Whitney Rank Sum Test and outcome data with Fishers Exact Tests. Statistical significance was set at P< or =.05. RESULTS Twenty-seven children aged 1 month to 12 years sustained airbag-related injuries. Sixty-one percent were girls. ISS ranged from 1 to 75 with a mean score (+/- SD) of 10 (14.5). All crashes were at reported speeds of less than 45 mph, and 64% were head-on collisions. No significant differences in the mean ISS (P = .074) occurred between groups. Both groups had similar closed head, ocular and facial injuries, extremity fractures, and number of deaths (P = 1.0). Abdominal organ injury was exclusive to the restrained group. Decapitation only occurred among unrestrained children. CONCLUSION Our data showed that airbags, with or without proper safety restraints, can lead to mortality or serious morbidity in children.

Fall injuries in the pediatric population: safer and most cost-effective management.

BACKGROUND At our childrens hospital, 30% of all trauma admissions are from falls. The aim of this study was to outline inefficiencies and unnecessary costs incurred in the care of these patients. METHODS The charts of 127 children admitted for falls (height > or = 9 feet) from 1993 to 1996 were reviewed. Patient demographics, injuries, and treatment costs were recorded and analyzed. RESULTS Fifty-seven children (45%) were evaluated at an outside facility before transfer. Of these, 73% had injuries requiring treatment at the pediatric center. Local hospital work-up resulted in an average treatment delay of 4.5 hours. Additionally, significant cost was incurred by duplication of radiographic studies, the majority of which were normal. CONCLUSION Improved and more cost-effective care in pediatric falls can be ensured by immediate transfer of patients with significant injuries, omission of radiographs before transfer, and avoidance of multiple routine x-ray films, the majority of which are normal.

Segmental Intestinal Ischemia: An Improved Method of Producing Small Bowel Injury

Previous animal models of intestinal ischemia-reperfusion have been successful in causing considerable mucosal damage, cellular destruction and sepsis. However, this often results in the death of the animal, making it impossible to examine the effects of modulators of the ischemic event. The sequence of morphologic and physiologic changes in the bowel from such injuries continues to be an area of intense examination. We have studied these changes by producing segmental intestinal ischemia in vivo in a rat model. By occluding a first-order branch of the superior mesenteric artery (SMA) and by selectively ligating terminal collateral branches, reproducible segmental intestinal ischemia was achieved. Bowel damage ranged from alterations in the villus structure to frank hemorrhagic necrosis of the intestinal wall. This model allows the study of hypoperfusion injury to the small intestine without total SMA occlusion, thus reducing the overall mortality.