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Biomedical subjects

D E Wesson

Publications and source records attributed to D E Wesson.

At least 91 records · Page 5Linked to original sources

Hypocalcemia-associated modulation of renal response to acute volume expansion in rats.

The present study used free-flow micropuncture and whole-kidney clearance studies to determine the renal response to normocalcemic vs. hypocalcemic acute volume expansion (AVE) in anesthetized Munich-Wistar rats. Animals received AVE with Ringer bicarbonate to 10% body weight; half of these animals were supplemented with calcium to maintain normocalcemia (VE + Ca2+) and half were allowed to become hypocalcemic (VE). Filtered load of chloride and total CO2 (TCO2) to the superficial proximal tubule and delivered load to the superficial loop segment were not different between groups. Superficial proximal tubule absolute Cl reabsorption was not different, but superficial loop segment absolute Cl reabsorption was less in the VE + Ca2+ animals (2,221 +/- 106 vs. 2,651 +/- 125 pmol/min, P less than 0.05) and whole-kidney fractional chloride excretion was greater (10.5 +/- 1.6 vs. 4.3 +/- 0.5%, P less than 0.05). When indomethacin (I) was administered to hypocalcemic (VE + I) and normocalcemic (VE + Ca2+ + I) AVE animals, both groups of animals had tubular and whole-kidney chloride reabsorption similar to VE animals. TCO2 reabsorption was not influenced by Ca2+ or I. The data indicate that normocalcemic vs. hypocalcemic AVE results in reduced superficial loop segment chloride reabsorption and greater whole-kidney fractional chloride excretion in the absence but not in the presence of prostaglandin inhibition. The data are compatible with an effect of hypocalcemia during AVE to limit superficial loop segment and whole-kidney chloride excretion by inhibiting renal prostaglandin synthesis.

Animals↗

Injury scoring systems in children.

Injury scoring systems are used to describe groups or individuals for purposes of epidemiologic studies, quality assurance or triage. The two most widely used methods are the injury severity score (ISS) and the trauma score (TS). In this paper, the authors describe their experience with these two methods in a group of 175 severely injured children. They found both to be reliable and valid but found the ISS the more useful of the two for various practical reasons.

Child↗

The pediatric passenger: trends in seatbelt use and injury patterns.

Injury patterns and use of passenger restraints were studied in 91 children injured while riding in motor vehicles and admitted to The Hospital for Sick Children, Toronto, from June 1984 through December 1985. Of theses, 44 had used restraints and 38 had not. Nine were excluded from the study because restraint use could not be determined. Age and sex distributions were closely matched in both study groups. The no-restraint group had more massive head injuries, thoracic injuries, and liver and spleen injuries than the restraint group. Classic "seatbelt syndrome" injuries were seen in the seatbelt group. The overall Injury Severity Scores were not significantly different between the groups. Despite mandatory legislation, many children do not use restraints, and many who do still suffer severe or fatal injuries. We conclude that better compliance with existing passenger restraint laws and more effective restraint systems are needed.

Accidents, Traffic↗

Growth and development in patients operated on for islet cell dysplasia.

Neonatal hypoglycemia caused by islet cell dysplasia (ICD), sometimes called nesidioblastosis, may lead to psychomotor retardation and neurologic dysfunction in up to 50% of patients who are not given early aggressive treatment. In 1979, we adopted a more aggressive protocol for treating this condition that consists of the following steps: immediate insertion of a silastic central venous line for reliable venous access; continuous intravenous infusion of glucose and glucagon to maintain euglycemia; oral diazoxide; and near total pancreatectomy if the first steps fail to overcome the hypoglycemia or the patient cannot be weaned off intravenous therapy. Twelve consecutive patients who underwent pancreatectomy for control of hypoglycemia between 1979 and 1984 were recalled and evaluated for growth delay, neurologic dysfunction, and psychomotor retardation using the Revised Yale Developmental Schedules, the Peabody Picture Vocabulary, and the Draw a Man Test. Follow-up ages ranged from 1.2 to 6.0 years with a median of 3.6 years. No significant growth abnormalities were identified. No patient exhibited focal neurologic dysfunction, although some demonstrated soft neurologic signs, which did not appear to be related to their earlier hypoglycemia. Psychomotor function for the group as a whole was normal, with a mean developmental quotient (DQ) of 99.2. The DQ was average for five patients and above average for four; no patient had a DQ in the frankly subnormal range. Psychomotor development correlated better with the family's socioeconomic and educational status than with the neonatal hypoglycemia. These children are developmentally and neurologically normal despite severe neonatal hypoglycemia. Continued follow-up will be necessary to detect any late sequelae.(ABSTRACT TRUNCATED AT 250 WORDS)

Body Height↗

Traumatic duodenal hematoma in the pediatric patient.

Twenty children with duodenal hematomas secondary to blunt trauma were treated between 1953 and 1983. The duodenal injury was isolated in ten cases and associated with intra-abdominal injuries in the others. In ten, the duodenal injury was suspected on admission and the diagnosis was confirmed within 24 hours by radiographic contrast studies. All ten were managed successfully with nasogastric suction and intravenous fluids. Ten patients underwent laparotomy for increasing abdominal tenderness and guarding. An isolated duodenal hematoma was found in four and treated by evacuation and/or gastroenterostomy. In five of the remaining six surgical patients, all of whom had multiple intra-abdominal injuries, the duodenum was left untouched. Three of these patients had postoperative contrast studies that showed early resolution of the duodenal hematoma. No duodenal stricture or leak developed in any patient. The children with isolated duodenal hematomas who were treated conservatively had a mean hospital stay of six days, whereas those treated surgically had a mean stay of 17 days. The ten patients with multiple intra-abdominal injuries had a mean hospital stay of 32 days. In this group, eight required total parenteral nutrition or nasojejunal feeds for nutritional support. In these patients, an isolated duodenal hematoma resulted in minimal morbidity and nonoperative management was usually successful. The presence of associated intra-abdominal injuries was responsible for the prolonged hospitalization and delayed return of normal intestinal function in some patients.

Abdominal Injuries↗

Repair of gastroschisis with preservation of the umbilicus.

A simplified technique for the repair of gastroschisis without the need to excise the umbilicus or make a fascial incision has been developed. First, the abdominal wall is stretched and the viscera are reduced. Next, the skin and subcutaneous tissue are elevated from the fascia for 1.5 cm around the defect and the fascia is closed transversely with interrupted sutures. The skin is also closed transversely. The umbilical stump is left intact. Eight of nine consecutive patients with gastroschisis were able to undergo repair by this technique. The average hospital stay was 35.6 days. There were no cases of omphalitis or cellulitis of the abdominal wall, but one child has a small umbilical hernia. All have a near normal-appearing umbilicus. This simpler technique for the repair of gastroschisis is quicker and less traumatic, and gives a better cosmetic result than the conventional method.

Abdominal Muscles↗

Preoperative home elemental enteral nutrition in complicated Crohn's disease.

Home elemental nutrition (HEN) was used in 11 children and adolescents with complicated Crohn's disease to relieve their immediate symptoms and make them more fit for definitive surgery. HEN resulted in symptomatic relief, weight gain from a mean of 47 to 53 kg (P less than .001) and reduction in prednisone requirements from a mean daily dose of 30 to 6 mg (P less than .001). The seven patients who subsequently underwent definitive bowel resection suffered no surgical complications. HEN was well tolerated by all patients. HEN offers a simple, safe, and cost effective means of preparing patients with complicated Crohn's disease for operation.

Adolescent↗

Incisionless gastrostomy for nutritional support.

A technique of percutaneous endoscopic gastrostomy was evaluated in 51 children and young adults aged 4 months to 26 years (mean, 9.7 years). Indications for gastrostomy included malnutrition secondary to cystic fibrosis, severe CNS disease, and others. The procedure was performed in 26 patients using local and topical anesthesia. General anesthesia was employed in children under 8 years of age. Duration of operative procedure ranged from 20 to 60 min. The average time for maintenance of feeding gastrostomy was 5.6 months. No procedure-related deaths were observed. Significant complications occurred less frequently than with traditional gastrostomy. We conclude that this procedure is technically simpler than, and at least as safe as, other methods of gastrostomy. It is especially useful in children for whom general anesthesia is best avoided.

Adolescent↗

Juxtamedullary nephrons during acute metabolic alkalosis in the rat.

The renal handling of bicarbonate during acute metabolic alkalosis was examined in Munich-Wistar rats using micropuncture techniques. Group I received an acute bicarbonate load, and fractional delivery of total CO2 (tCO2) (FDtCO2) to the superficial late distal tubule (LD) was significantly lower than to the base of the papillary collecting duct (B) (18.4 +/- 1.7 vs. 22.9 +/- 1.5%; P less than 0.01), indicating net addition of bicarbonate between LD and B. When acutely bicarbonate-loaded rats had their deep nephrons destroyed with bromoethylamine hydrobromide (BEA) (group II), net addition of tCO2 between LD and B was abolished and net reabsorption uncovered (FDtCO2 LD: 28.0 +/- 3.6 vs. B: 17.5 +/- 2.5%; P less than 0.01). The infusion of amiloride (2.5 mg/kg body wt) to alkalotic rats treated with BEA (group III) completely inhibited distal bicarbonate reabsorption but did not reestablish addition (FDtCO2 LD: 27.6 +/- 1.6 vs. B: 26.1 +/- 3.7%; P = NS). The values obtained for sham-operated animals (group IV) were the same for group I. The patterns that were observed between LD and B were reproduced for the four groups of animals when FDtCO2 LD was compared with the fractional excretion of bicarbonate in the urine of the intact contralateral kidney. These studies suggest that juxtamedullary nephrons contribute a higher load of bicarbonate than superficial nephrons to the final urine during acute metabolic alkalosis in the rat.

Alkalosis↗

Treatment of acute cyanide intoxication with hemodialysis.

A dramatic response was noted in a patient at our hospital who received hemodialysis therapy for severe acidosis secondary to an unknown toxin, subsequently identified as cyanide. We were unable to find any information concerning the hemodialysis clearance and extraction ratio of cyanide; thus, we studied the effect of hemodialysis in dogs receiving a constant infusion of cyanide with and without a simultaneous infusion of thiosulfate. The hemodialysis clearance of cyanide in the presence of thiosulfate was 38.3 +/- 5.4 ml/min with an extraction ratio of 0.43 +/- 0.06 (n = 4). Hemodialysis was found to increase the lethal dose of cyanide without thiosulfate infusion, and a further increase was noted with the thiosulfate infusion. Thiosulfate promotes mitochondrial metabolism of cyanide to thiocyanate. The end product, thiocyanate, is quickly removed by hemodialysis. We believe that the demonstrated effectiveness of hemodialysis in the treatment of acute cyanide intoxication is related not only to the hemodialysis clearance of cyanide, but also to the removal of its metabolic end product, thiocyanate. Based on our observations, we feel that hemodialysis is an effective adjunct in the treatment of acute cyanide intoxication.

Acidosis↗

Massive obesity and nephrotic proteinuria with a normal renal biopsy.

The association between massive obesity and nephrotic syndrome has been rarely reported. We herein describe a patient with massive obesity (209 kg) and nephrotic proteinuria who had a normal renal biopsy. The patient was initially polycythemic and had a supranormal creatinine clearance. After losing 89 kg, his hemoglobin and creatinine clearance returned to normal, and proteinuria decreased to 300 mg/24 h. We postulated that increases in glomerular hydrostatic pressure may result in local alterations of glomerular basement membrane sieving characteristics (biologic membrane thixotropy) with resultant nephrotic proteinuria. Prompt remission of proteinuria with weight loss supports a reversible glomerular hemodynamic alteration as a mechanism for the proteinuria of massive obesity.

Adult↗

Urokinase in the treatment of occluded central venous catheters in children.

Urokinase was used to clear occluded silastic central venous catheters in 14 pediatric patients. The catheters, which had been placed into a neck vein and tunnelled out through the skin of the anterior chest wall, were being used for either long-term parenteral nutrition or chemotherapy. Occluded catheters that could not be cleared by simple flushing with heparinized saline were filled with a solution of urokinase, which was left in place for 2 hours before the catheter was flushed a second time. Twenty-one occluded catheters were managed in this way over a period of 14 months. There were no allergic reactions or bleeding complications. Twelve of the 21 occluded catheters were immediately cleared. Three catheters ruptured during attempted flushing maneuvers but were patent after repair. Two catheters remained partially occluded. Only four catheters were removed because of persistent occlusion. When simpler techniques fail, urokinase instillation appears a safe and effective alternative to the more common practice of removing occluded central venous catheters in children.

Adolescent↗

The effect of intrauterine esophageal ligation on growth of fetal rabbits.

Babies with pure esophageal or duodenal atresia weight less than normal babies at birth. Whether this is due to the obstruction to fetal swallowing or some other cause is not known. To determine how intrauterine interruption of swallowing affects fetal growth, we developed a model of esophageal atresia in the fetal rabbit. Twenty-five time-mated rabbits at 24 days gestation were anesthetized with halothane and ketamine. The uterus was exposed through a midline abdominal incision. The head and neck of the fetus in the distal end of one horn were isolated through a 2-cm hysterotomy. Biparietal diameter (BPD) was measured and the esophagus was isolated and ligated through a midline cervical incision. The fetus in the distal end of the opposite horn underwent sham operation. Four days later, cesarean section was done. The newborn rabbits were weighed, and crown/rump length and BPD were measured. Ligation of the esophagus was confirmed by re-exploration of the neck. Three does died under anesthesia and two aborted. From the remaining 20, 156 fetuses were recovered, of which 135 were alive. One set of operated fetuses was dead, leaving 19 pairs for analysis. There was a statistically significant reduction in weight gain (31.7 +/- 1.3 g to 29.1 +/- 0.9 g, P less than 0.05) following interruption of the esophagus but linear growth was unchanged. Obstruction to normal fetal swallowing may account for the low birth weight with normal head circumference reported in babies with esophageal and duodenal atresia.

Animal Nutritional Physiological Phenomena↗

The relationship between PaCO2 and ventilation parameters in predicting survival in congenital diaphragmatic hernia.

Fifty-eight infants with congenital diaphragmatic hernia presenting within the first 6 hours of life, who underwent surgical repair, were analysed prospectively in order to produce a reliable index of severity of disease that would reliably predict eventual outcome. All were treated with paralysis hyperventilation and intravenous (IV) isoproterenol for the first 48 hours. There were 30 survivors and 28 deaths in this series (mortality 48%). Using arterial PCO2 values measured 2 hours after surgical repair and correlating them with an index of mechanical ventilation (mean airway pressure and respiratory rate), we have been able to clearly define two groups of diaphragmatic hernia based on their response to IPPV. The first group, with CO2 retention and severe preductal shunting, was unresponsive to hyperventilation with high rates and pressures; the mortality was 90%. The second group responded well to hyperventilation and demonstrated reversable ductal shunting only. Survival in this group was 97%. Only four patients out of 58 exhibited the "honeymoon period," with a period of stability followed by severe ductal shunting. Arterial CO2 accurately reflects the degree of lung development in this disease and separates those patients with severe pulmonary hypoplasia, where the outcome is invariably fatal, from those with a well-developed contralateral lung where there is excellent potential for survival.

Carbon Dioxide↗

Neonatal intestinal pseudoobstruction.

In the past 10 years, the diagnosis of pseudoobstruction lasting more than two months was confirmed in 10 infants after sepsis, meconium ileus, and Hirschsprung's disease were excluded, and surgery or autopsy failed to demonstrate a site of mechanical intestinal obstruction. Four infants had undergone prior operation for another anomaly: gastroschisis (2) and ileal atresia (2). Five of the remaining infants also had megacystis. The lack of coordinated intestinal motility was best appreciated by radiocontrast small bowel studies, which showed degrees of aperistalsis or segmentation. Rectal manometric studies were not helpful. Histology of the intestine was normal in seven, while a gross deficiency of nerve fibres was noted in one patient and a myopathy of smooth muscle in another. A variety of drugs used to stimulate peristalsis were ineffective. Seven patients had 25 operations, often to exclude mechanical causes of obstruction. The mainstay of treatment was TPN and intestinal decompression. Six children survived; their ages ranged between 8 months and 9 years (median age, 16 months). There has been improvement in intestinal peristalsis in five children, three of whom now tolerate a regular diet and two of whom are on TPN and are currently increasing oral intake. Four infants died, two from sepsis, two from TPN-related hepatic failure. In contrast to previous reports, we conclude that intestinal pseudoobstruction may be self-limited in some neonates, including those with megacystis. Therapy should consist of long-term nutritional support and treatment of other anomalies that may be present.

Combined Modality Therapy↗

Fat overload syndrome causing respiratory insufficiency.

The fat overload syndrome developed in a 7-year-old girl who was on home TPN which included 20% Intralipid (total lipid dose 3.2 g/kg/d). Acute respiratory insufficiency developed with cough, dyspnea, tachypnea, and cyanosis. The chest x-ray revealed mild cardiomegaly and pulmonary edema. Blood gases showed profound hypoxia (PaO2 29 torr on room air). Spontaneous resolution occurred over the next seven days as the lipemia cleared.

Child↗

Surgical management of persistent neonatal hypoglycemia due to islet cell dysplasia.

We have reviewed ten children who underwent surgical therapy for persistent neonatal hypoglycemia over a 5-year period. All had inappropriately high insulin levels in the face of hypoglycemia, and all failed medical management with intravenous glucose, frequent feeds, diazoxide and glucagon. Two groups of five patients each were analysed retrospectively. Group 1 underwent 95% pancreatectomy, leaving a small amount of pancreatic tissue on the duodenum and common bile duct. The only major complication in this group was in one patient with common duct obstruction requiring choledochoduodenostomy. All these children are developing normally, without diabetes, steatorrhea, or recurrent hypoglycemia. Group 2 underwent 85% pancreatectomy, leaving the uncinate process in situ. Two of these children are well. Two required conversion to 95% resection because of recurrent hypoglycemia; one of these required a subsequent total pancreatectomy, at which time the pancreatic remnant had significantly regenerated. The other Group II patient was normoglycemic but died at age 3 from pneumonia. Pathology in nine cases showed islet cell dysplasia; 5 of these also had microadenomatosis. One case had a histologically normal pancreas. We conclude that 95% pancreatectomy is a safe operation with a lower failure rate than less radical resections, and should be used early in the management of this condition.

Female↗