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Biomedical subjects

H L Magill

Publications and source records attributed to H L Magill.

At least 37 records · Page 2Linked to original sources

Blood pressure increases, birth weight-dependent stability boundary, and intraventricular hemorrhage.

The blood pressure (BP) and transcutaneous PO2 (TcPO2) changes associated with intensive care procedures were evaluated to determine whether responses differ between babies with and without periventricular-intraventricular hemorrhage (PV-IVH). Fifty-three inborn babies less than or equal to 1500 g were studied using a microcomputer-based monitoring system. With almost any procedure including a seemingly benign one such as a diaper change, peak systolic BP increased and TcPO2 decreased. However, responses to interventions did not differ between babies with PV-IVH and those without PV-IVH. Neither did these responses differ between those with birth weight less than or equal to 1000 g and greater than 1000 g. When each baby's record was scanned for the highest peak systolic BP before diagnosis of PV-IVH or within 48 hours in those with no PV-IVH and their BP points plotted against birth weight, a stable region was evident wherein PV-IVH occurred at a lower incidence (13%). When peak systolic BP was beyond this stable region, the incidence of PV-IVH was significantly higher, 70% (P less than .0001). The stability boundary for the maximum systolic BP is birth weight-dependent; the limit for the highest tolerable peak systolic BP is lower for the low-birth-weight infant. In over 70% of instances the highest peak systolic BP was associated with motor activities either induced by nursery procedures or spontaneous. We speculate that decreasing the frequency of intensive care interventions may decrease episodic BP increases to levels beyond the birth weight-dependent stability boundary where PV-IVH is likely to occur.

Birth Weight↗

Michel dysplasia. Common cavity inner ear deformity.

A case is reported in whom there was a unilateral complete arrest of differentiation of the otocyst associated with an ipsilateral mild hemifacial hypoplasia and auricular abnormalities. The patient's tympanic membrane and VII nerve function were normal and a normal ossicular mass was identified on CT Scan. This case illustrates that development of the middle ear cavity (exclusive of structures on the medial wall), external ear canal and VII nerve can be independent of development of the inner ear and that a unilateral absence of otic capsule differentiation can take place without severe associated abnormalities.

Child, Preschool↗

Indomethacin reduces the risks of severe intraventricular hemorrhage.

A prospective, random selection, double-blind clinical trial was carried out to determine the efficacy of indomethacin in preventing periventricular-intraventricular hemorrhage (PV-IVH). Babies who were born in our institution, had birth weights less than or equal to 1500 gm, and had no PV-IVH or grade 1 PV-IVH were given either placebo (n = 70) or indomethacin (n = 71), 0.2 mg/kg intravenously at 6 hours of age and 0.1 mg/kg at 18 and 30 hours. Two major outcomes were determined: the development of grades 2 to 4 PV-IVH and the development of severe PV-IVH (i.e., hemorrhages with blood filling greater than 50% of the ventricles and in some cases with associated parenchymal echodensities). Grades 2 to 4 PV-IVH occurred in 16 (23%) of the indomethacin group and 27 (39%) of the placebo group (p less than 0.03). The incidence of severe PV-IVH was 3% in the indomethacin-treated babies and 14% in the control group (p less than 0.02). The influence of other perinatal factors on the incidence of grades 2 to 4 or severe PV-IVH was determined by stepwise logistic regression. Placebo use, early grade 1 PV-IVH, lower birth weight, and higher fraction of inspired oxygen at 6 hours of life were associated with higher estimated odds of the development of grades 2 to 4 PV-IVH. Placebo use, male gender, lower 5-minute Apgar score, and a large base deficit were predictive of severe PV-IVH. Estimated odds ratios of severe PV-IVH with placebo use and male gender were 11.25:1 and 9:1, respectively. Thus indomethacin prophylaxis reduced the relative risk of grades 2 to 4 PV-IVH and severe PV-IVH, but other perinatal variables contributed significantly to the overall risk of PV-IVH.

Apgar Score↗

The relationship between labor and route of delivery in the preterm infant.

The purpose of this prospective study was to evaluate the effects of the active phase of labor and route of delivery on the frequency of germinal layer/intraventricular hemorrhage in 89 infants with ultrasound-estimated fetal weights less than or equal to 1750 gm. Twenty-eight infants (31.5%) had germinal layer/intraventricular hemorrhage within 1 hour after birth and an additional 15 infants (17%) had germinal layer/intraventricular hemorrhage beyond 1 hour after birth. Infants with germinal layer/intraventricular hemorrhage had a significantly lower gestational age (p less than 0.003) and birth weight (p less than 0.007). Germinal layer/intraventricular hemorrhage within 1 hour after delivery was increased in the infants of women who experienced the active phase of labor regardless of the route of delivery. However, the incidence of germinal layer/intraventricular hemorrhage beyond 1 hour after delivery and the overall incidence were similar in the vaginal delivery and cesarean delivery groups. In addition, there was an increased incidence of progression to grades III and IV hemorrhage regardless of route of delivery in the infants whose mothers experienced the active phase of labor.

Apgar Score↗

Extralobar pulmonary sequestration and mediastinal bronchogenic cyst.

A child with coexisting mediastinal bronchogenic cyst and extralobar pulmonary sequestration is presented. Two distinct lesions were suggested by barium esophagram and confirmed by a chest computed tomography scan. The diagnostic and embryologic relationship of the two lesions is discussed.

Bronchogenic Cyst↗

Significance of pulmonary computed tomography at diagnosis in Wilms' tumor.

Pulmonary lesions were found by computed tomography (CT) despite normal chest roentgenograms (CXR) at diagnosis in 11 of 124 patients with Wilms' tumor. All patients were entered on a treatment protocol at St Jude Children's Research Hospital from 1978 to 1986. The 11 patients all had favorable histology Wilms' tumor. Staging and therapy were based on interpretation of the CXR and abdominal findings. Excluding CT findings, one patient had stage I disease, two stage II, seven stage III, and one stage IV on the basis of multiple liver metastases. Four patients have relapsed: one with stage II and three with stage III. All relapses have been pulmonary. Overall, 4/11 (36%) relapsed. This relapse rate is considerably greater than the 20% overall relapse rate of patients treated according to this protocol though not statistically significant. These relapses suggest that such patients may be at increased risk for pulmonary recurrence. The results also indicate that small lesions initially noted only on CT scans of the chest in children with Wilms' tumor frequently represent metastatic tumor. Further studies of larger numbers of patients will be necessary to confirm these findings.

Antineoplastic Agents↗

Progression of mild ureteropelvic junction obstruction in infancy.

Mild and clinically silent ureteropelvic junction obstruction was observed to progress in severity in 2 infants. Diuretic renography was useful in serial evaluation and documentation of progression. The possible mechanism for such progression of obstruction is proposed. Although mild obstruction in the older child and adult can be followed successfully without surgery, it appears that close follow-up of mild obstruction during the first year of life is necessary to detect and assure treatment of progressive obstruction at an optimum age.

Diuresis↗

Thickening of infant feedings for therapy of gastroesophageal reflux.

To assess the effect of thickening of feedings on gastroesophageal reflux and gastric emptying, 20 infants were examined with technetium scintigraphy and detailed behavioral observation after each of a pair of feedings, one with radiolabeled infant formula alone and the other with radiolabeled formula thickened with dry rice cereal. The thickened and unthickened meals were followed by similar amounts of scintigraphically demonstrated gastroesophageal reflux. However, the number of episodes of emesis (1.2 +/- 0.7 vs 3.9 +/- 0.9 per 90 minutes postprandial), the percent of gastric emptying at 30 minutes (17.8% +/- 2.7% vs 22.4% +/- 2.4%), the time spent crying (11.7 +/- 3.1 minutes vs 17.6 +/- 3.8 minutes per 90 minutes), and the total time spent awake (45.2 +/- 5.9 minutes vs 53.1 +/- 4.9 minutes per 90 minutes) were significantly less after the thickened feedings. Because thickening of infant feedings increases the caloric density, decreases emesis, decreases crying time, and increases sleep time in the postprandial period, it is likely to be beneficial in the treatment of infants with gastroesophageal reflux associated with failure to thrive.

Crying↗

Diagnostic imaging in children with urinary tract infection: review of current concepts and suggested guidelines.

Symptomatic urinary tract infection (UTI) in childhood is estimated to occur with a frequency of up to 3% through adolescence. The practitioner caring for children requires both anatomic and physiologic information concerning the urinary tract to assist in diagnosis, treatment, and prognosis. Advances in diagnostic imaging have resulted in numerous methods for evaluation of the urinary system. These procedures differ in the type of information obtained, risk or discomfort to the patient, and cost. Selection of the proper test(s) requires an understanding of these factors. Based on our survey of recent pertinent literature and our clinical experience, we present guidelines for appropriate diagnostic imaging in children with UTI, and we discuss the benefits and limitations of available imaging techniques along with concepts regarding the pathogenesis of UTI and causes of renal damage from UTI.

Child↗

Pediatric digital subtraction angiography: intraarterial and intracardiac applications.

Intraarterial digital subtraction angiography (IA-DSA) was performed in 80 pediatric patients. Forty-four underwent arterial injections with digital filming techniques. Of the 130 injections, DSA imaging was good or excellent in 121, often allowing resolution of vessels 1 mm in size. Thirty-six of the 80 patients underwent cardiac evaluation with intra-cardiac injections. Improved contrast resolution with IA-DSA allowed the use of smaller catheters (3-4F) and smaller amounts of contrast material. Immediate availability of subtracted images (no film processing delay) resulted in shorter total procedure time. Outpatient studies are possible. IA-DSA provides several notable advantages for the pediatric patient.

Adolescent↗

Hyperimmunoglobulinemia E syndrome: pulmonary imaging considerations.

The Hyper IgE syndrome is a rare disease consisting of recurrent sinusitis and pneumonia, pneumatoceles, chronic dermatitis, and elevated serum levels of IgE. The primary radiographic abnormalities are recurrent alveolar lung disease and pneumatoceles. Pneumothorax may occasionally occur as in one of our cases. Other causes of pneumatoceles are usually easily excluded by the history and other clinical data. Pulmonary scintigraphy and computed tomography may add information valuable to the management of these patients.

Adolescent↗

Delayed presentation of traumatic intraperitoneal bladder rupture.

A child with urine ascites as a delayed manifestation of post-traumatic intraperitoneal bladder rupture is presented. The diagnosis was suggested by abdominal CT scan and confirmed with a cystogram. While uncommon, late presentation of intraperitoneal bladder rupture following trauma may occur from masking of a primary laceration or development of secondary rupture at the site of a hematoma in the bladder wall. Since CT may be a primary diagnostic study performed following abdominal trauma, the radiologist should be aware of CT findings suggesting bladder rupture and of the possibility of delayed presentation of this injury.

Child, Preschool↗

Infantile hypophosphatasia: normalization of circulating bone alkaline phosphatase activity followed by skeletal remineralization. Evidence for an intact structural gene for tissue nonspecific alkaline phosphatase.

After a 3-month course of weekly intravenous infusions of pooled normal plasma in an attempt at enzyme replacement therapy, we observed gradual and prolonged normalization of circulating alkaline phosphatase (AP) activity in a boy with infantile hypophosphatasia. During this 4-month period, when hypophosphatasemia had been corrected, electrophoretic and heat denaturation studies suggested that the AP in serum was skeletal in origin. Serial radiographic and histologic studies of bone demonstrated skeletal remineralization and the appearance of AP activity in osteoblasts and chondrocytes after the infusions. Considerable clinical improvement coincided with the skeletal remineralization. Our observations indicate that in one patient with infantile hypophosphatasia the structural gene for the tissue-nonspecific (bone/liver/kidney) AP isoenzyme was intact and could be expressed with marked physiologic effect. Infantile hypophosphatasia may result from absence or inactivation of a circulating factor(s) that regulates the expression of the gene for tissue nonspecific AP.

Alkaline Phosphatase↗

Partial plasma exchange transfusion improves cerebral hemodynamics in symptomatic neonatal polycythemia.

Cerebral arterial pulsatile flow changes and the effect of partial plasma exchange transfusion on these pulsatile flow patterns were studied in neonatal polycythemia/hyperviscosity syndrome by transcutaneous Doppler technique. Twenty-two infants with cord blood hematocrit greater than 58% (greater than 2 SD above the mean) were studied from a total of 2,400 infants who were screened for cord hematocrit over a 6-month period. Each of 22 infants had the following initial studies: radial artery hematocrit, viscosity, intracranial pressure measurement, and anterior cerebral arterial Doppler study to determine pulsatility index, mean systolic, mean end diastolic, and mean flow velocities, and area underneath the curve of the velocity tracings/min. Twelve of 22 infants had radial artery hematocrit less than 63%, were normoviscous (less than 13.5 cps, 11.25 sec-1) and were designated as control infants. Ten (study infants) were polycythemic (hematocrit greater than or equal to 63%) and hyperviscous (greater than or equal to 13.5 cps, 11.25 sec-1). All study patients were treated by partial plasma exchange transfusion. Initial studies were repeated after exchange transfusion. Control infants were not treated. Prior to exchange procedure, the polycythemic hyperviscous infants had significantly higher hematocrit, viscosity, and pulsatility index; the other Doppler measurements and heart rate were lower than those of control babies. The exchange procedure resulted in significantly decreased hematocrit, viscosity, and pulsatility index and increase in the other Doppler measurements, heart rate, and intracranial pressure. All postexchange measurements of study infants were not statistically different from the control infants. These data suggest that neonatal polycythemia/hyperviscosity syndrome may be associated with abnormal cerebral hemodynamics that could improve with partial plasma exchange transfusion.

Blood Viscosity↗

Excretory urography with iohexol: evaluation in children.

A multicenter clinical study was conducted using iohexol, a second-generation nonionic contrast medium, for excretory urography performed in 130 children. Doses of iohexol (300 mg iodine/ml) ranged between 150 and 660 mgI/kg (0.5 and 2.2 ml/kg). Iohexol was tolerated well, and no significant adverse reactions occurred. Sixty-five iohexol urograms were evaluated to determine the minimum dose for adequate visualization of the kidneys and collecting systems. A dose greater than 300 mgI/kg (1.0 ml/kg) always resulted in a urogram of diagnostic quality, while visualization was insufficient for diagnosis in 10% of studies done with doses of 150-300 mgI/kg (0.5-1.0 ml/kg). Another 65 iohexol urograms were compared in a blinded manner with a similar number of studies performed using iothalamate meglumine at comparable iodine concentration and dose. Visualization of calyces and pelvoinfundibular structures achieved with iohexol was rated better with statistical significance, but there was no difference in visualization of the renal parenchyma or ureters. Use of iohexol in excretory urography may be advantageous in children who are at greatest risk for an adverse reaction to contrast media or in those most likely to benefit from use of a low osmolality contrast agent.

Adolescent↗

CT peritoneography in evaluation of pediatric dialysis complications.

Intraperitoneal contrast material with CT scanning was used to evaluate three children with multiple recurrences of peritonitis and no obvious source of infection while they were undergoing continuous-cycling peritoneal dialysis. In one child a loculus of uno-pacified dialysate was readily identified, confirming sonographic findings that suggested an inflammatory pseudocyst. In the other two children, contrast material dispersed throughout the peritoneal dialysate, suggesting that recurrent peritonitis occurred from extraperitoneal contamination. CT peritoneography is easily performed with contrast material instilled through the peritoneal dialysis catheter. Combining anatomic imaging with intraperitoneal-fluid dynamics, this technique should provide more complete evaluation of the peritoneal cavity than other imaging methods. While additional evaluation is necessary, our initial experience suggests the usefulness of CT peritoneography in excluding an intraperitoneal source of infection during long-term peritoneal dialysis.

Adolescent↗