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Biomedical subjects

R W Powell

Publications and source records attributed to R W Powell.

At least 37 records · Page 2Linked to original sources
PubMed1991

A tungsten-supplemented diet delivered by transplacental and breast-feeding routes lowers intestinal xanthine oxidase activity and affords cytoprotection in ischemia-reperfusion injury to the small intestine.

Ischemia-reperfusion injury has been implicated as playing a major role in the development of necrotizing enterocolitis, a major cause of morbidity and mortality in the newborn. A tungsten-supplemented molybdenum-free diet can reduce xanthine oxidase (XO) enzyme activity in the intestine, which in turn reduces the generation of oxygen radicals after an ischemia-reperfusion insult. This study evaluated the ability of this diet to be effective by indirect means, ie, transplacental and breast-feeding routes. XO activity of the intestine was measured in three groups of CD-1 white rats: I, weanlings fed the tungsten diet or standard chow for 1 week; II, 1-day-old rat pups whose mothers were maintained on the tungsten or standard chow for 7 to 10 days prior to term; and III, rat pups at 1 and 3 weeks after birth whose lactating mothers were maintained on the tungsten or standard chow. Some animals from group III also underwent either a 30- or 60-minute episode of occlusion of the superior mesenteric artery (SMA) to evaluate the protective effects of the diet. XO activity was significantly reduced in all groups receiving the tungsten diet (P less than .0001). Blinded histopathologic studies of the entire small bowel showed significantly less villar necrosis (P less than .05) and fibrosis (P less than .0001) in the tungsten-treated group than in the controls. In the 60-minute occlusion study all tungsten-group animals survived, whereas 7 of 12 in the control group died of intestinal infarction within 24 hours (P less than .001).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Intraoperative evaluation of intestinal ischemia: a comparison of methods.

Methods for evaluating intestinal ischemia include standard clinical criteria, Doppler ultrasonography, and intravenous fluorescein injection. Each has disadvantages, and a combination of methods is often used. The purpose of this study was to determine whether surface oximetry could be used to assess perfusion in an animal whose intestinal diameter approximates that of infants. Reversible arterial, venous, and arteriovenous occlusion was studied in rabbit intestines. After 6 to 8 hours of occlusion, intestinal vascularity was evaluated by the four methods listed. Doppler ultrasonography and surface oximetry were found to be unreliable tools for assessing perfusion in this animal model. We conclude that standard clinical criteria and fluorescein remain the standards for intraoperative evaluation of intestinal perfusion.

Animals↗
PubMed1990

Necrotizing enterocolitis in multiple-birth infants.

Over a 5-year period, 20 infants of multiple-gestation births (16 twin, 2 triplet) developed necrotizing enterocolitis (NEC) (15 infants) or suspected NEC (5 infants). During the same period, 532 infants of multiple gestations were admitted to our neonatal intensive care unit, yielding a NEC incidence in this population of 3.8%. In two twin sets, both infants developed NEC or suspected NEC, and in three sets only the affected twin was transferred to our nursery. Five infants required surgical intervention (25%) and three infants died (overall mortality, 15%). Fifteen siblings who did not develop NEC served as a control group. Analysis showed that the 1-minute Apgar score was the most significant factor in predicting NEC (P less than .028) and need for surgical intervention (P less than .020). In this series, 82% of the infants with 1-minute Apgar less than 6 developed NEC, whereas 31% with 1-minute Apgar greater than 6 developed NEC.

Apgar Score↗
PubMed1989

Diagnostic pneumoperitoneum in the pediatric patient with a unilateral inguinal hernia.

Controversy continues among surgeons over the management of pediatric patients with unilateral groin hernias. Currently, advocated treatment modalities include repair of only the clinically apparent side, exploration of the contralateral side when the ipsilateral hernia is repaired, or performance of contrast herniography before surgery. Another technique for consideration--diagnostic intraoperative pneumoperitoneum--is a simple, quick, safe, and highly accurate means of detecting a clinically inapparent contralateral inguinal hernia during the initial surgery. This technique, the results of its use, and a review of the literature are included.

Adolescent↗
PubMed1989

Breast masses in young women.

To better define the risk of breast cancer in young patients, a retrospective review of all breast biopsies in women under age 40 years at Grady Memorial Hospital, Atlanta, from Dec 1, 1981, to Aug 15, 1987, was performed. During this time, 751 biopsies were performed on patients aged 9 to 40 years. None of the 128 patients aged 20 years or less had carcinoma. Of 150 patients aged 21 to 25 years, two had carcinoma. At age 26, there began a steady rise in the incidence of carcinoma, such that in the 36- to 40-year age group, carcinoma was present in 24.4% of the specimens. This retrospective review confirms previous reports that suggest that carcinoma of the breast is distinctly unusual in patients under age 20 and that breast masses in these young patients should be managed conservatively. As the incidence of carcinoma increases with the age of the patient, one's threshold for excisional biopsy should decrease.

Adenofibroma↗
PubMed1989

Costs vs. quality.

Explore the source record for details and available documents.

Costs and Cost Analysis↗
PubMed1989

Hirschsprung's disease in adolescents. Misadventures in diagnosis and management.

Three male adolescents, ages 13, 15, and 17 years, presented with complications of their Hirschsprung's disease, including acute enterocolitis with sepsis, chronic enterocolitis with anemia and leukocytosis, and severe fecal impaction. All had experienced delay in diagnosis resulting from either physician error in diagnosis or physician misinformation concerning the surgical treatment of the disease. These three patients illustrate some of the pitfalls in the diagnosis and surgical management of patients with Hirschsprung's disease. Misinformation concerning the surgical correction of this disease still exists, and these patients emphasize the necessity of continued, updated information in the diagnosis, management, and outcome of patients with Hirschsprung's disease.

Adolescent↗
PubMed1988

The protective effect of pneumococcal vaccination following partial splenectomy.

Weanling CD-1 male rats were subjected to 100, 75, and 50% splenectomy. One week following splenectomy, animals received either a sham immunization with 0.1 ml NS or pneumococcal immunization with 0.1 ml of a polyvalent (23) vaccine. Eight weeks following surgery, all animals received an intraperitoneal inoculation with 10(6) Streptococcus pneumoniae Type 3 organisms and were observed for mortality. Significant differences in mortality were seen between sham and immunized animals undergoing 100 or 75% splenectomy, while in the 50% group a difference was noted which did not reach statistical significance (Mantel-Cox log rank test). Patients undergoing greater than 50% splenectomy may be afforded greater protection against overwhelming pneumococcal infections by immunization with pneumococcal vaccine.

Animals↗
PubMed1988

Cervical esophageal obstruction by ectopic gastric mucosa.

A 5-year-old boy presented with dysphagia, and barium swallow revealed a narrowing in the upper esophagus. Biopsies of the circumferential lesion showed gastric mucosa. The heterotopic gastric mucosa was resected via a cervical approach. After resolution of a minor anastomotic leak, he remains asymptomatic 10 years following resection with no evidence of recurrence by esophagrams and endoscopy.

Child, Preschool↗
PubMed1988

The predictive validity of the Pediatric Trauma Score.

The Pediatric Trauma Score was evaluated in 450 injured children by a paramedic in the field and a physician in an E.D. There was agreement between the scores of these two individuals 93.6% of the time, correlation coefficient 0.991, r2 = 0.982. Further testing at the 0.01 level of significance indicated that a positive association existed between these two variables in the population from which our sample was drawn. Mortality for the group was 2.9%. No deaths occurred in patients whose PTS was greater than 8, which was defined as the Critical Triage Point. The sensitivity of the PTS when used for triage at the critical triage point was 95.8%. The specificity of the PTS was 98.6%. The Pediatric Trauma Score appears to be highly accurate, reliable, predictable, and easy to use for assessing the severity of injury and hence is a straightforward modality for triage of injured children.

Adolescent↗
PubMed1988

The efficacy of postsplenectomy sepsis prophylactic measures: the role of penicillin.

The well documented increased susceptibility of the asplenic host to overwhelming sepsis by encapsulated organisms has led to three popular prophylactic measures in patients: 1) pneumococcal vaccination; 2) vaccination with oral penicillin prophylaxis; or 3) vaccination with penicillin use at the first sign of infection. An animal model (weanling CD-1 rats) was utilized to evaluate these prophylactic measures. One hundred sixty rats underwent splenectomy and were divided into four treatment groups: I) sham vaccination; II) pneumococcal vaccination; III) vaccination and IM penicillin 24 hours after intraperitoneal inoculation of 10(6) Streptococcus pneumoniae type III; IV) vaccination and IM penicillin starting 3 days before IP inoculation. Six days following the bacterial challenge survival rates by group were: I) 5%; II) 25%; III) 100%; IV) 100% (p less than 0.001 by phi 2 likelihood ratio). Mantel- Cox log rank analysis of survival curves yielded significant differences between all groups except III and IV (p less than 0.001). This study in weanling rats supports the use of penicillin in the asplenic host. Daily prophyactic penicillin or penicillin started at the first sign of infection appears to be equally effective. Randomized studies in humans would determine the best regimen.

Animals↗
PubMed1988

Resuscitative thoracotomy in children and adolescents.

Accidental injury continues as the leading cause of mortality in children and adolescents. With the recent push for improvement in emergency medical services and specialized trauma centers for this age group, more moribund patients can be expected to reach these centers. Multiple reports document the efficacy of resuscitative thoracotomy in the moribund adult trauma victim, but published reports of this technique in children and adolescents are lacking. From January 1981 to July 1986, 19 patients ranging in age from 4 to 18 years (mean 14) underwent resuscitative thoracotomy. Eleven patients sustained penetrating trauma while eight sustained injuries from blunt trauma. Five patients survived and were discharged from the hospital (26%). There were no survivors in the 0-15 year age group in five penetrating injuries and four blunt trauma victims. This review confirms the efficacy of resuscitative thoracotomy in the patient with penetrating trauma. Salvage in the blunt trauma victim is possible, but less than in penetrating injuries (12.5% versus 36%). Further studies in this age group will be necessary to establish appropriate guidelines for the use of RT in children and adolescents.

Adolescent↗
PubMed1987

Intraoperative diagnostic pneumoperitoneum (Goldstein test) in the infant and child with unilateral inguinal hernia.

Over a 3 year period, 191 infants and children underwent operative repair of inguinal or communicating hydroceles or both. Of these patients, 131 underwent the Goldstein test to determine the presence or absence of a contralateral hernia sac. The Goldstein test was performed by introducing a soft rubber catheter through the hernia sac into the abdominal cavity and distending the peritoneal cavity with air. The contralateral groin and, in males, the scrotum were then palpated for crepitance. The presence of crepitance constituted a positive test result. Of the 131 tests performed, the results were positive in 38 (29 percent) and negative in 93 (71 percent). There was one false-positive test result (2 percent) and no false-negative results. The test was not performed in 60 patients because of technical problems in passing the catheter (22 percent), presence of a ventriculoperitoneal shunt (2 percent), previous contralateral herniorrhaphy (1.6 percent), presentation with bilateral hernias (26 percent), and patient age of 12 years (1 percent). Continued differences in approaches to the management of pediatric patients who present with unilateral groin hernias prompted this study. We believe that the Goldstein test represents a safe, economical, rapid, accurate, and humane approach to this common problem.

Adolescent↗
PubMed1987

Surgical problems in the fetus: a multidisciplinary approach.

Over a 2 year period, 90 cases of potential fetal pathologic conditions were presented to a multidisciplinary fetal board. Members, including persons from perinatology, neonatology, genetics, radiology, pathology, pediatric surgery, neurosurgery, and urology, met monthly to discuss new referrals, follow-up ongoing cases, and present findings and treatment in delivered cases. Of 90 referred cases, 76 surgical diagnoses occurred in 71 fetuses (79 percent), with central nervous system and genitourinary anomalies predominating. A formal presentation during a single meeting with the variety of specialists necessary to manage surgical problems in the fetus facilitated perinatal management and allowed for the appropriate specialist to counsel the parents as early as possible.

Congenital Abnormalities↗
PubMed1987

Peritoneal lavage in pediatric patients sustaining blunt abdominal trauma: a reappraisal.

One hundred twenty-eight patients from 0 to 18 years of age underwent diagnostic peritoneal lavage following blunt abdominal trauma. Seventy-eight had negative lavages and 50 were positive. Forty-one patients underwent exploratory celiotomy after positive lavage results. A review of the operative findings and need for surgical intervention led to the conclusion that 12 of these operations were not necessary. Due to the oversensitivity of peritoneal lavage a strongly positive result mandates further diagnostic evaluation unless the patient's clinical status requires exploratory celiotomy.

Abdominal Injuries↗
PubMed1987

Pediatric maxillofacial trauma: unique features in diagnosis and treatment.

The purpose of this study was to review mechanisms, etiologies, associated injuries, and treatment of maxillofacial trauma in children and to compare them to similar adult injuries. Thirty blunt injuries (1984-1986) comprised the children's group, and 176 injuries, the adult group. Multiple associated injuries were more common in children, the most frequent being CNS and orthopedic injuries. Detailed anatomy of mandibular fractures required pleuridirectional tomography in 63% of the pediatric cases compared to 12% in adults. In the children's group, the mandibular fractures were favorable in 56% of cases compared to 15% in adults. Children required shorter periods of intermaxillary fixation with no child requiring reapplication of fixation. Based on these comparisons, a protocol for the management of pediatric maxillofacial injuries has been developed.

Accidents, Traffic↗
PubMed1986

Postsplenectomy sepsis in pediatric patients following splenectomy for trauma: a proposal for a multi-institutional study.

Eighteen patients less than 15 years of age (range, 1.5 to 15 years) were followed prospectively after undergoing splenectomy for blunt trauma. Follow-up time ranged from 1 to 12 years with a mean of 5.8 years. During the follow-up period significant septic episodes developed in two of the 18 (11.0%) patients. During the same period 16 patients less than 15 years of age (range 2 to 15 years) who underwent splenorrhaphy were followed. In none of the patients in the splenorrhaphy group has sepsis developed to date (P = .11). Follow-up studies in both groups included a CBC, peripheral smear, platelets counts, history of infections, and radionuclide scans in the patients undergoing splenorrhaphy. The two patients with significant sepsis were an 18-month-old male with pneumococcal septicemia and a 13-year-old with meningococcal meningitis. Both patients survived these episodes. Although the numbers are small, this prospective study reemphasizes the increased risk of sepsis in the asplenic pediatric patient and the need for close surveillance, parental education, appropriate immunizations, and vigorous treatment of infections. The methods used in this prospective study of patients from one institution could be expanded to a multi-institutional study to obtain prospective data concerning the natural history of pediatric patients undergoing splenectomy because of trauma.

Adolescent↗