Specificity and functional impact of post-exercise depression of cortically evoked motor potentials in man.

Magnetic stimulation of the motor cortex with electromyographic recordings from exercising muscles has shown corticospinal excitability to be depressed following exercise. We now investigate whether this depression spreads to non-exercising muscles and its influence on performance. Healthy volunteers made unilateral biceps curls to exhaustion and, in another later session, for 25% of the time to exhaustion. Bilateral motor-evoked potentials (MEPs) in biceps brachii and first dorsal interosseus muscles were measured at 2-min intervals before and after exercise. In another experiment, subjects performed exhaustive curls and, in addition to MEP areas, force production in biceps, hand-grip force, simple reaction times and movement times were measured bilaterally. MEPs were depressed after exhaustive exercise in the exercising biceps for over 60 min; depression was also observed 10-15 min after exercise in the non-exercising biceps but not in the first dorsal interosseus of either hand. The shorter exercise period produced depression of MEPs only in the exercising muscle. After exhaustive exercise maximum voluntary contraction fell in the exercising biceps and this correlated with MEP areas. No reduction in force was seen in the non-exercising biceps but hand-grip force fell slightly in both arms. There was no change in reaction times or movement times. Depression of MEPs can occur in non-exercising homonymous muscles but not in heteronymous muscles and only when exercise levels are high. There was no measurable functional deficit in the non-exercising limb, so we conclude that the reduced corticospinal excitability observed in this limb has little or no consequence on the performance parameters measured.

Perforation of the intussuscepted colon.

Hospital records were reviewed of almost 1,000 infants and children with intussusception during a 25 year period. Among the approximately 850 who had barium enemas, six had colonic perforations during the attempted hydrostatic barium enema reduction of the intussusception. All occurred in patients 6 months old or less. Most had preceding viral illness, four had pain, all vomited, five had rectal bleeding, and only one had a palpable mass. All were pale, dehydrated, lethargic, and had intermittent mottling of the skin and complete bowel obstruction. All had been ill for over 36 hr. The perforations occurred through areas of necrotic ischemic colon. All infants required a right hemicolectomy. These babies seem to fit a pattern in which they are younger and sicker longer than the average patient with intussusception and have complete bowel obstruction. These facts are a warning that such infants are at increased risk for a barium enema bowel perforation.

Colon perforation during attempted barium enema reduction of intussusception.

In reviewing the records of almost 1000 infants and children with intussusception in two children's hospitals over the last 25 yr, there have been seven bowel perforations during attempted hydrostatic barium enema reduction of an intussusception. Except for one instance, these have all occurred during the last 6 yr. The infants were all 6 mo old or less and most had a preceeding viral illness. Only 4 of the 7 had pain, all vomited, in only 2 was a mass felt and all but 1 had rectal bleeding. The duration of these signs and symptoms was longer than 36 hr with most ill for 3 or 4 days. All seven infants had abdominal x-rays that showed complete small bowel obstruction. Once the intussusception was suspected, barium enema reduction was attempted without excessive hydrostatic pressure and not for a prolonged time; all the ileocolic intussusceptions were met in the transverse colon with only a minimal reduction produced. It was at this time that a perforation was suddenly noted. All infants required immediate right hemicolectomy for the area (s) of colonic necrosis. Postoperatively, there were two wound infections, a volvulus which left the child with a short gut and another infant suffered severe brain damage. These babies seem to fit a pattern in which they are younger and sicker longer than the average infant with an intussusception, and have a complete small bowel obstruction. These facts may be a warning that such infants are at increased risk for a barium enema bowel perforation.

Unsuspected esophageal foreign bodies.

Retrospective study of ten infants and young children in whom an unsuspected foreign body was found in the esophagus revealed that all had had wheezing of difficulty swallowing solid food. In four, stridor or wheezing had been ascribed to respiratory infection. All foreign bodies were in the upper esophagus. Their presence can cause prolonged, severe morbidity. They can be identified by radiography of the neck and chest, occasionally supplemented by barium studies.

Bone scintigraphy in chondroblastoma.

Scintigraphy in 3 patients with chondroblastoma showed that the tumors were hyperemic and avidly accumulated the radionuclide. These changes were also present in adjacent normal bone, but to a lesser degree. This suggest that radionuclide uptake in chondroblastoma is a function of the blood supply to the tumor rather than primary matrix extraction.

Obstructive circular-muscle defect in the small bowel in a one-year-old child.

Investigation to determine the cause of vomiting in a 14-mo-old child revealed partial obstruction at a narrowed segment of mid small bowel, with local deficiency of circular muscle and ballooning proximally. The pathogenesis of this apparently unique lesion is uncertain.

Peritoneal calcification in a neonate with imperforate hymen.

Contrast medium for vaginography in a premature neonate passed into the peritoneal cavity; calcification in that area apparently represented genital-tract secretions which had accumulated above the imperforate hymen. Ultrasonography of the mother's abdomen had indicated fetal ascites, a finding that may be of value in diagnosing genital-tract obstruction prenatally.

Abnormalities of the urinary tract in association with congenital cardiovascular disease.

The incidence of urinary tract abnormalities in a group of infants and children with congenital cardiovascular disease was determined by assessing roentgenograms of the abdomen taken following angiocardiographic studies. The urinary tracts of 400 of these patients were so outlined, but in 50 others the tracts could not be outlined. In 21 of the latter the urinary tracts were assessed at autopsy.Of these 421 children, nine (approximately 2%) had serious urinary tract disease, and 15 (approximately 3.5%) had anomalies which were of no clinical significance.The incidence of four renal anomalies-bifid collecting system, rotated kidney, horsehoe kidney and ectopic kidney-was compared with that in another group of patients without cardiovascular disease. No significant difference was found in the incidence of these four anomalies in the two groups.