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Biomedical subjects

D T Wilcox

Publications and source records attributed to D T Wilcox.

At least 55 records · Page 3Linked to original sources

The urological manifestations of hollow visceral myopathy in children.

PURPOSE: Hollow visceral myopathy is a rare clinical entity characterized by impaired intestinal function in the absence of mechanical occlusion. It can affect the smooth muscle of the whole or segments of the gastrointestinal tract and occasionally the urinary tract. We examined the urological manifestations of hollow visceral myopathy and management in the pediatric population. MATERIALS AND METHODS: We reviewed the records of 14 male patients 1 day to 2 years old (mean age 4.6 months) and 10 female patients 1 day to 5 years old (mean age 9.4 months) at presentation to our institution with hollow visceral myopathy. In all patients genitourinary tract ultrasound, voiding cystourethrography and serum creatinine measurement were done at presentation. RESULTS: All patients had gastrointestinal obstructive symptoms at presentation and 11 (46%) had urological symptoms, including urinary retention in 2, urinary tract infection in 3, and a prenatal diagnosis of megacystis and hydroureteronephrosis in 6. Overall 22 patients (92%) had urological abnormalities, all had poor bladder emptying and recurrent urinary tract infections, and 13 had megacystis associated with bilateral hydroureteronephrosis in 9 and unilateral hydroureteronephrosis in 2. There were 9 deaths from extensive gastrointestinal involvement and sepsis. Of the surviving 15 patients 13 have urological abnormalities, including 8 who perform and tolerate clean intermittent catheterization via the urethra and are well. Of the 4 male infants who did not tolerate clean intermittent catheterization appendicovesicostomy was done in 1, a Casale tube was placed in 1 and vesicostomy was performed in 2. The remaining female patient has day and night wetting. CONCLUSIONS: Urological abnormalities are common in hollow visceral myopathy and they can contribute to presenting symptoms. Clean intermittent catheterization via the urethra to aid in bladder emptying and decrease the frequency of urinary tract infections is the mainstay of treatment but surgery to construct an alternative catheterizable channel or vesicostomy may be required in intolerant patients.

Child, Preschool↗

Contributions by individual lungs to the surfactant status in congenital diaphragmatic hernia.

Laboratory evidence has recently confirmed clinical reports suggesting that the surfactant system is abnormal in congenital diaphragmatic hernia (CDH). Autopsy series show that, although both lungs are affected by the maldevelopment, the ipsilateral lung is more severely affected. The aim of this study was to examine the surfactant status in each lung in a lamb model of CDH. The lamb CDH model was created on the left side at 80 d of gestation and delivered near term. Subsequently, the lungs were removed and separated from each other. Bronchoalveolar lavage and type II pneumocyte isolations were performed on each side separately. Lavage analyses showed decreased phospholipid (0.12 versus 0.42 mg/g), per cent phosphatidylcholine (51% versus 79%) surfactant-associated protein A (0.20 versus 2.68 mg/g), and surfactant-associated protein-B (0.35 versus 2.21 mg/g) in CDH lungs compared with control lungs. However, no differences were seen between the ipsilateral and contralateral lungs of either CDH or control groups. This was in contrast to the phosphatidylcholine biosynthetic abilities of type II cells isolated from CDH lungs, which were not only lower than those from control lungs (0.15 versus 0.40 nmol/10(6) cells/h), but were also significantly worse in the ipsilateral CDH lung compared with the contralateral CDH lung (0.10 versus 0.20 nmol/10(6) cells/h). Further studies utilizing radiolabeled exogenous surfactant injected in the lower contralateral lung indicate that discrepancies between the presence of type II cell function differences between lungs, and the lack of biochemical differences between the two lungs in CDH, may be due to in utero mixing of lung fluid.

Animals↗

Redefining the genital abnormality in the Robinow syndrome. -004.

PURPOSE: We defined the anatomical structure of the male genital abnormality in the Robinow syndrome. Features of this syndrome include mesomelic brachymelia of the arms, bifid terminal phalanges of the hands and feet, characteristic facies, skeletal anomalies and hypoplastic external genitalia. MATERIALS AND METHODS: Penile anatomy of 3 patients with the Robinow syndrome was assessed using computerized tomography and magnetic resonance imaging. Results were compared to those of 4 controls who underwent imaging for pelvic malignancies. RESULTS: Cross-sectional imaging showed that normal penile crura were inserted onto the anteromedial aspect of the pubic bone. In contrast, in the Robinow syndrome they were inserted inferiorly and posteriorly onto the medial aspect of the ischial tuberosity. In addition, the crura in the Robinow syndrome extended posterior to a line intersecting both femoral shafts. Compared to controls, there was a significant gap between the symphysis pubis and dorsal aspect of the penis. CONCLUSIONS: The penile anomaly in the Robinow syndrome is due to abnormal insertion of the penile crura, resulting in a penis that appears shorter and more inferiorly placed between the legs.

Abnormalities, Multiple↗

Cholelithiasis in early infancy.

This report describes three children, age range 7 weeks to 5 months, who presented with obstructive jaundice secondary to gallstones. Previous Escherichia coli septicaemia and frusemide therapy were predisposing risk factors in two of the patients. All three were successfully treated with cholecystectomy and exploration of the common bile duct.

Ampulla of Vater↗

Haemorrhage from a duodenal ulcer in a neonate.

A 7-week-old boy born at 32 weeks' gestation developed massive upper gastrointestinal bleeding from a duodenal ulcer. The base of the ulcer had eroded into the hepatic artery. Haemorrhage was only controlled following operation.

Duodenal Ulcer↗

Prenatal diagnosis of congenital diaphragmatic hernia with predictors of mortality.

Since the late 1970s, congenital diaphragmatic hernia (CDH) has been diagnosed antenatally by ultrasound. With improvements in ultrasound resolution, CDH is being diagnosed more frequently and at an earlier stage in gestation. This provides an opportunity to administer in utero therapy to the fetus. As 50% of babies born with CDH survive, it is imperative that accurate prognostic indicators are available to guide antenatal therapy. Antenatal diagnosis and prognostic indicators are discussed.

Hernia, Diaphragmatic↗

Pulmonary parenchymal abnormalities in congenital diaphragmatic hernia.

Congenital diaphragmatic hernia results in abnormal lung development. There is a global hypoplasia with both lungs affected, the ipsilateral lung more severely. This results in a reduction in the number of bronchial divisions and a decrease in the quantity and maturity of the alveoli. The pneumocytes are dysfunctional, resulting in a total quantitative and qualitative reduction in surfactant and a decrease in antioxidant enzyme activity.

Hernias, Diaphragmatic, Congenital↗

Animal models in congenital diaphragmatic hernia.

The first animal model of congenital diaphragmatic hernia (CDH) was described in 1967. This was a late-gestational, surgically-created lamb model. Since then, animal modeling has become more sophisticated. Using a variety of techniques and laboratory species, animal models have been produced to investigate the pathophysiology of CDH, from whole animal physiology studies to lung molecular changes. To provide the animal tissue required, three different approaches have been used: (1) a surgically-created model which has been reported in lambs and rabbits, (2) a teratogen-induced model which to date has been described in rats and mice, and (3) a congenital model which is present in a specific pig herd. All animal models are discussed in this article.

Animals↗

Pathophysiology of congenital diaphragmatic hernia. XVI: Elevated pulmonary collagen in the lamb model of congenital diaphragmatic hernia.

The pathophysiologic features of congenital diaphragmatic hernia (CDH) include pulmonary hypoplasia, pulmonary hypertension, surfactant deficiency, and decreased pulmonary compliance. When the surfactant deficiency is corrected using exogenous surfactant therapy, the pulmonary compliance improves, but does not reach normal values. Quasistatic saline pressure-volume measurements, which eliminate the air-liquid interface, confirm that CDH lungs are intrinsically less compliant than control lungs. The authors hypothesized that this abnormal lung compliance results from elevated concentrations of collagen and/or elastin in the lung. Therefore, they measured the collagen and elastin concentrations in CDH and control lung tissue. Also measured was the collagen concentration in the kidney, intestine, and dissected third-generation arterioles, venules, and bronchioles, to characterize further the pathology of CDH. The CDH model was created on the left side of fetuses in pregnant ewes at 80 days' gestation. The fetuses were delivered and killed at 140 days (full term, 145). The concentrations of collagen (as hydroxyproline), elastin, DNA, and total protein were measured using standard techniques. Although there was significantly more collagen per gram of lung tissue in the CDH lungs (1.334 mg/g v 0.885 mg/g in the controls) the elastin concentrations were not different. The elevated collagen concentration was not associated specifically with the conducting airways or vasculature. The collagen concentrations in CDH kidneys and intestines were the same as those of controls. The DNA/total protein ratios in the CDH and control lungs were identical. The results suggest that the elevated collagen concentration was present only in the lungs of CDH lambs, and that it was not attributable to atrophy or hypertrophy of the lungs. Thus, increased collagen in the lung parenchyma may be responsible for the intrinsic stiffness and decreased compliance of the CDH lungs.

Animals↗

Pathophysiology of congenital diaphragmatic hernia. XII: Amniotic fluid lecithin/sphingomyelin ratio and phosphatidylglycerol concentrations do not predict surfactant status in congenital diaphragmatic hernia.

Abnormal development of the lung in congenital diaphragmatic hernia (CDH) results in a dysfunctional surfactant system. In premature newborns at risk for respiratory distress syndrome, amniotic fluid lecithin/sphingomyelin (L/S) ratios and phosphatidylglycerol (PG) status have been successfully used to predict the surfactant status in the fetus. The objective of this study was to assess the accuracy of L/S ratios and PG in predicting the surfactant status in CDH. The surgically created lamb CDH model was used. Animals were delivered at 140 days' gestation (term 145) and immediately killed. Before delivery amniotic fluid was collected and L/S ratios and PG status were measured. Bronchoalveolar lavage (BAL) was performed and analyzed for total phospholipid and percent phosphatidylcholine (PC). Analysis of the BAL showed that the CDH lungs had both significantly less total phospholipid (CDH 0.10 +/- 0.03 mg/g versus control (CON) 0.76 +/- 0.28 mg/g) and PC (CDH 38 +/- 7.3% versus CON 70 +/- 3.4%) when compared with controls. In contrast the L/S ratios (CDH 2.44 +/- 0.26 versus CON 2.01 +/- 0.32) and PG status (CDH 8.75 +/- 1.01 nmol versus CON 10.2 +/- 0.9) were the same in CDH and control animals. The BAL from the CDH lamb model has a significant surfactant deficiency. Amniotic fluid L/S ratios and PG status were, however, not different between the control and CDH lambs. These results indicate that amniotic fluid L/S ratios and PG do not accurately predict the surfactant status of a fetus with CDH.

Amniotic Fluid↗

Pathophysiology of congenital diaphragmatic hernia. XI: Anatomic and biochemical characterization of the heart in the fetal lamb CDH model.

AIM: The purpose of this study was to determine whether the presence of bowel in the chest during development in the fetal lamb model of congenital diaphragmatic hernia (CDH) results in structural and/or biochemical hypoplasia of the left venticle. METHODS: The model was created at 80 days' gestation and delivered at term. The hearts were fixed in 4% formaldehyde solution, components weighed, and right ventricular (RV) and left ventricular (LV) wall thicknesses and both aortic (Ao) and pulmonary artery (PA) root diameters were measured. Fresh specimens were analyzed for protein, DNA, hydroxyproline, and elastin content. All CDH measurements are compared with littermate control tissues. RESULTS: There were no differences in body weight (kg) between CDH and control littermates (4.25 +/- 0.26 versus 3.71 +/- 0.24, P = NS). CDH lambs have significantly decreased total heart (4.88 +/- .25 versus 6.75 +/- .49, P < .05), left ventricular (1.65 +/- .11 versus 2.15 +/- .19, P < .05), septal (1.29 +/- .11 versus 1.99 +/- .21, P < .05), and combined atrial (0.68 +/- .06 versus 1.14 +/- .15, P < .05) weights (g/kg lamb) without differences in RV weights (1.26 +/- .07 versus 1.57 +/- .17, P = NS). LV and RV wall thickness, and Ao root diameters (cm) were found to be identical in both CDH and control lambs. However, PA root diameters (0.47 +/- .01 versus 0.38 +/- .01, P < .005) and ductus arteriosus diameters were increased in CDH (0.35 +/- .01 versus 0.22 +/- .02, P < .005). Total protein, DNA collagen, and elastin content and DNA/total protein ratios were identical in RV and LV in both CDH and control lambs. CONCLUSION: Newborn lambs with left-sided CDH have a significantly lower total heart, LV, septal, and atrial weights without differences of RV weight or ventricular wall thicknesses. Given these findings, the unchanged DNA/protein ratio implies that the left ventricle is hypoplastic in CDH. Ao/PA root ratios suggest that LV hypoplasia in utero may result in increased left atrial pressures, decreased right-to-left shunting through the foramen ovale, and increased PA pressures and flow, resulting in increased PA root and ductus arteriosus diameters. This model simulates the clinical data from human fetuses/neonates with CDH. Further investigations are necessary to determine the functional significance of these findings.

Animals↗

Spontaneous pneumothorax: a single-institution, 12-year experience in patients under 16 years of age.

OBJECTIVE: To characterize the natural history and outcome of spontaneous pneumothorax in patients under age 16 years. DESIGN: This is a retrospective review in which all patients admitted to the authors' institution (between December 1980 and July 1993) with a diagnosis of spontaneous pneumothorax were included. Information was obtained from the hospital records. SETTING: This study was performed in a university childrens' hospital. PATIENTS: All patients under 16 years with a diagnosis of spontaneous pneumothorax were included. RESULTS: Seventeen patients were admitted and analyzed. Only three admissions were for recurrence. The main symptoms included chest pain (100%), shortness of breath (41%), and cough (6%). Chest tube drainage was successful in 65% of the cases; the median time was 4 days. Two patients had a persistent air leak. An underlying cause was recognized in 42% of cases. Seven operations were necessary, and the mean follow-up periods is 31 months, with no recurrence reported to date. CONCLUSION: Spontaneous pneumothorax occurs in the pediatric population, although it is less common in adults. An underlying pathology is more frequently observed in pediatric patients, but recurrence is less common. Chest tube drainage alone is sufficient treatment for the majority of patients; however, a significant number require some form of surgical intervention.

Adolescent↗

Pathophysiology of congenital diaphragmatic hernia. VIII: Inhaled nitric oxide requires exogenous surfactant therapy in the lamb model of congenital diaphragmatic hernia.

The pathophysiology of the lamb model of congenital diaphragmatic hernia (CDH) involves pulmonary hypoplasia, pulmonary hypertension, and surfactant deficiency. Inhaled nitric oxide (NO) is a highly selective pulmonary vasodilator. The aim of this study was to determine the effects of inhaled NO on pulmonary gas exchange, acid-base balance, and pulmonary pressures in a lamb model of CDH with or without exogenous surfactant therapy. At the gestational age of 78 days (full term, 145 days) 11 lamb fetuses had a diaphragmatic hernia created via a left thoracotomy and then were allowed to continue development in utero. After cesarean section, performed at term, six lambs received exogenous surfactant therapy (50 mg/kg, Infasurf) and five served as controls. All animals were pressure-ventilated for 30 minutes and then received 80 ppm of inhaled NO at an F1O2 of .9 for a 10-minute interval. Compared with the control lambs, the lambs with exogenous surfactant therapy had higher pH (7.17 +/- .06 v 6.96 +/- .07; P < .05), lower PCO2 (73 +/- 8 v 122 +/- 20, p < .05), and higher PO2 (153 +/- 38 v 50 +/- 23; P < .05). In control CDH lambs (without surfactant), inhaled NO did not improve pH, PCO2, or PO2, or decrease pulmonary artery pressure. In CDH lambs given exogenous surfactant, NO decreased pulmonary artery pressures (42 +/- 4 v 53 +/- 5; P < .005) and further improved PCO2 and PO2. NO also made the difference between pulmonary and systemic artery pressures more negative in the surfactant-treated lambs (-15 +/- 4 v -2.3 +/- 2.4; P < .005).(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Inhalation↗

Pathophysiology of congenital diaphragmatic hernia. X: Localization of nitric oxide synthase in the intima of pulmonary artery trunks of lambs with surgically created congenital diaphragmatic hernia.

The pathophysiology of congenital diaphragmatic hernia (CDH) results from a combination of pulmonary hypoplasia, pulmonary hypertension, and surfactant deficiency. Previously we demonstrated that inhaled nitric oxide (NO), a known vasodilator, only improves oxygenation and decreases pulmonary artery pressures when the lamb model of CDH is pretreated with exogenous surfactant. Nitric oxide synthase (NOS) in endothelial cells is responsible for the production of NO, a mediator of smooth muscle cell relaxation. Pulmonary hypertension in CDH may result from a defect in the endogenous production of NO. Our aim was to determine whether the main pulmonary artery trunks in CDH lambs have NOS immunoreactivity. Cryostat sections of paraformaldehyde-fixed specimens of pulmonary artery and aortic rings from 10 CDH lambs and five control lambs were processed for NADPH-diaphorase activity. Immunolocalization of NOS was studied in paraformaldehyde-fixed sections and compared with serially cut specimens from identical rings that were tested for NADPH-diaphorase activity. Intense NADPH-diaphorase staining was present in the intimal layer (endothelial lining) of the pulmonary artery and aortic rings of both the CDH and control lambs. This activity colocalized with NOS immunoreactivity in all specimens. Both NOS immunoreactivity and NADPH-diaphorase staining were lacking in cartilage, which were used as negative controls. NOS is present in the main pulmonary artery trunks of CDH lambs. To our knowledge, this is the first report of NOS immunoreactivity in CDH. We can only speculate whether this activity is preserved in other areas of the vascular tree in CDH, ie, pulmonary capillaries and veins. Perhaps the pulmonary hypertension in CDH is not caused by an NOS deficiency.

Amino Acid Oxidoreductases↗

Perfluorocarbon-associated gas exchange improves pulmonary mechanics, oxygenation, ventilation, and allows nitric oxide delivery in the hypoplastic lung congenital diaphragmatic hernia lamb model.

OBJECTIVES: To determine the efficacy of perfluorocarbon-associated gas exchange and the effects of inhaled nitric oxide during perfluorocarbon-associated gas exchange in the congenital diaphragmatic hernia lamb model. DESIGN: Prospective, nonrandomized, controlled, nonhuman trial. SETTING: Animal research facility. SUBJECTS: Fetal lambs of 16 time-dated pregnant ewes, at 80 days gestation (term 140 to 145 days). MEASUREMENTS AND MAIN RESULTS: The congenital diaphragmatic hernia lamb model was created in 16 animals. Twelve animals survived to be studied. All animals were mechanically ventilated for 4 hrs with a time-cycled, pressure-limited ventilator. Perfluorocarbon-associated gas exchange was started after 15 mins of ventilation (n = 6). Blood gases were analyzed at 30 mins and then hourly. The perfluorocarbon-associated gas exchange animals had dynamic compliance and tidal volumes measured. After 1 hr, inhaled nitric oxide (80 parts per million) was delivered to the perfluorocarbon-associated gas exchange animals for 10 mins. All blood gas parameters, including pH (6.72 +/- 0.06 vs. 7.14 +/- 0.07), PCO2 (186 +/- 12 vs. 70.5 +/- 16.7 torr [24.8 +/- 1.6 vs. 9.5 +/- 2.1 kPa]), and PO2 (48 +/- 17 vs. 156 +/- 48 torr [6.4 +/- 2.3 vs. 20.8 +/- 6.4 kPa]) were significantly improved in the perfluorocarbon-associated gas exchange-treated group at 4 hrs (p < .005). Dynamic compliance (0.13 +/- 0.02 vs. 0.32 +/- 0.06 mL/cm H2O/kg) and tidal volume (3.5 +/- 0.35 vs. 7.22 +/- 0.61 mL/kg) were also significantly (p < .001) increased in the perfluorocarbon-associated gas exchange group. In the perfluorocarbon-associated gas exchange animals, nitric oxide caused a significant (p < .05) increase in oxygenation and a reduction in pulmonary hypertension. This effect was reversed by stopping the inhaled nitric oxide. CONCLUSIONS: Perfluorocarbon-associated gas exchange significantly improved gas exchange, dynamic compliance, and tidal volumes. Furthermore, inhaled nitric oxide can be effectively delivered during perfluorocarbon-associated gas exchange to reduce pulmonary hypertension and enhance oxygenation.

Animals↗