Biomedical subjects
Publications and source records attributed to W L Smith.
It is very important to have a thorough knowledge of the anatomy of cutaneous sinuses and fistulae prior to surgical intervention. This paper describes a modification of the Seldinger technique for the demonstration of these sinuses and fistulae, especially those extending into bone.
Sacrococcygeal teratomas often present at birth as skin-covered caudal masses. Because of the variable intrapelvic and presacral extension of these tumors, high mortality from hemorrhage, variable blood supply, and occasional confusion with other caudal masses, preoperative arteriography is useful. The arteriographic findings in 4 neonates with sacrococcygeal teratoma are presented.
A plastisol coupler has been designed that improves acoustical coupling for linear array ultrasound transducers. This device improves both ease in scanning and image quality in real-time scanning of the infant brain.
Small surface electrodes were placed bilaterally over the intermediate or lateral cerebellar cortex of cynomolgus monkeys to determine how electrical stimulation of different areas of the cerebellar cortex affected average evoked responses and a sequential forelimb movement. Biphase electrical stimulation was applied between various electrode combinations, and various intensities and frequencies were established for each combination. Transcortical stimulation between the right and left intermediate cerebellar cortex required the lowest intensity (1.5 microC/sq cm/ph) to elicit an average evoked response in the sensorimotor cortex; stimulation between the electrodes over the contralateral intermediate or lateral cortex required slightly higher levels (2.0 microC/sq cm/ph). No response could be elicited from stimulating the ipsilateral cortex. Likewise, 1 minute of transcortical stimulation was more effective than comparable stimulation of the contralateral intermediate or lateral cortex in altering the waveforms of a somatosensory evoked response. Transcortical stimulation also modified the forelimb movement, whereas contralateral stimulation of the intermediate or lateral cortex had little or no effect. Transcortical stimulation at 2.0 microC/sq cm/ph, with frequencies of 150 Hz or higher, increased the time required to execute the forelimb movement but did not affect the accuracy of the movement. High-speed motion pictures indicated that transcortical stimulation decreased the velocity of forelimb movement and in some cases also affected the limb trajectory. These results indicate that consideration should be given to the area of the cerebellum stimulated and to the mode of stimulation, in the hope of achieving optimum clinical benefit.
The concentration of cyclooxygenase protein in uterine caruncles is increased on days 13 to 15 of the ovine estrous cycle prior to decreases in plasma progesterone concentrations and at the same time when increases in uterine luteolysin (PGF2 alpha) secretion are reported to occur. This finding suggests that luteolysin synthesis is controlled, in part, by the activity of the cyclooxygenase. All caruncular cell types stain positively for cyclooxygenase antigenicity and thus can form prostaglandin endoperoxides. The cyclooxygenase in a model cell type, mouse 3T3 cells, has been localized on the endoplasmic reticulum and nuclear membrane using an immunocytochemical method.
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The hydronephrotic rabbit kidney exhibits elevated basal prostaglandin synthesis and supersensitivity to peptide stimulation of vascular prostaglandin and thromboxane formation. In this study the distribution of the prostaglandin-forming cyclooxygenase in hydronephrotic and contralateral rabbit kidneys following one and four day ureteral obstructions was compared using immunohistofluorescence. No alterasions were detected in the distribution or intensity of cyclooxygenase-positive fluorescence in the renal vasculature in response to ureteral obstructions. However, two significant differences were noted between hydronephrotic and contralateral kidneys in the staining of renal tubules: (a) the intensity of fluorescent staining in cortical and medullary collecting tubules of the hydronephrotic kidney was increased and (b) cyclooxygenase antigenicity appeared in the thin limbs of Henle's loop in the hydronephrotic organ. Although alterations in prostaglandin formation by the renal vasculature have been documented previously, our results indicate that ureteral obstruction also causes increased prostaglandin synthesis by renal tubules.
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Bone scan findings are presented from five consecutive cases of metastatic osteogenic sarcoma. Every patient had pulmonary metastases which concentrated the bone imaging radiopharmaceutical to some degree. In one patient, the diagnosis of pulmonary metastasis was made prior to our seeing any radiographic abnormalities. The mechanism by which skeletal imaging agents localize in pulmonary lesions is not clear. Unsuspected skeletal metastases were also discovered on scans in two patients, both of whom had normal radiographs. Diagnosis of hypertrophic pulmonary osteoarthropathy was made in one patient with normal radiographs. These findings indicate that bone scans as well as radiographs should be performed routinely in preoperative staging and followup of patients with osteogenic sarcoma.
Mucocutaneous lymph-node syndrome (MCLS) is an acute exanthem with specific clinical features, sometimes complicated by involvement of internal organs. Two patients with MCLS had clinical and radiographic evidence of mechanical small-bowel obstruction, probably on the basis of focal vascular insufficiency, as anatomic obstruction was not documented in either instance. The cases indicate that intestinal involvement in patients with MCLS can simulate intestinal obstruction, and conservative management of such patients is appropriate.
Diagnostic radiation exposure in 133 consecutive newborns was studied using a TLD monitoring system. Eighty-eight per cent of dosimeters received less than 1 mSv (100 mrem) total exposure. The mean exposure per chest radiograph was 0.044 +/- 0.023 mSv (4.4 +/- 2.3 mrem). Abdominal surface exposure was 0.053 +/- 0.03 mSv (5.3 +/- 3.0 mrem) for boys and 0.044 +/- 0.021 mSv (4.4 +/- 2.1 mrem) for girls. The gonadal exposure, which was calculated from the abdominal exposure data, was 0.053 +/- 0.030 mSv (5.3 +/- 3.0 mrem) for boys and 0.026 +/- 0.012 mSv (2.6 +/- 1.2 mrem) for girls. The correction factor for beam attenuation over gonads in girls was 0.58. In general, the radiation received by these infants did not exceed the currently published protection limits.
This study was designed to assess the diagnostic efficacy of the routine lateral chest film in symptomatic newborn infants. The initial anteroposterior chest film was supplemented by alateral view in 53 consecutive patients on admission to the newborn intensive care unit. Subsequently three radiologists and two neonatologists performed independent analysis of the anterposterior films with and without the lateral view. A total of 530 observations were tabulated. Assessment of degree of lung inflation and discovery of abnormalities of the heart, mediastinum, and trachea were unaffected by the use of the lateral radiograph. A correct primary diagnosis was made in 74% of all cases by the anteroposterior chest film alone and in 71% by the anteroposterior/lateral series. Degree of confidence in the primary diagnosis did not change when the lateral chest radiograph was added. There was no appreciable difference in detection of complicatins of the primary disease in either series. We conclude that the risks (e.g., radiation and environmental disturbance) of the routine admission lateral chest radiograph are substantially greater than any benefits to be gained.
This is the first report of an hepatic mesenchymal hamartoma causing congestive heart failure in an infant. These benign tumors usually present as a bulky abdominal mass but rarely can present with congestive failure when the angiomatous component is prominent.
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The VATER association is a group of congenital anomalies with a nonrandom tendency for concurrence. Defects include vertebral, vascular, anorectal malformation, tracheoesophageal fistula with esophageal atresia, radial-limb, and renal abnormalities. The critical period of organogenesis is at or before the sixth or seventh week of gestation. The VATER assoication is important in the evaluation of newborns with major congenital anomalies.
An immunohistofluorescence procedure for detecting prostaglandin-forming cyclooxygenase has been used to localize the enzyme in the renal cortex of the cow, guinea pig, rabbit, rat, and sheep. Cyclooxygenase antigenicity was found in endothelial cells lining all arteries and arterioles and in cortical collecting tubules in each species examined. The enzyme was also detected in epithelial cells of Bowman's capsule in the rabbit and in mesangial cells in both ovine and bovine glomerular tufts. That prostaglandins can be formed in renal resistance vessels suggests that it is the synthesis occurring in these vessels which is responsible for the effects of prostaglandins on renal blood flow. Of further note is the correlation that exists between the location of the cyclooxygenase and that of the antidiuretic hormone-responsive adenyl cyclase in the distal nephron.
Increased activity of prostaglandin synthetase in spontaneously hypertensive rats (SHR) during development has previously been reported. The investigations reported herein utilized an immunofluorescent technique to qualitatively assess the activity of the first enzyme in the PGE2 biosynthetic pathway, the prostaglandin-forming cyclooxygenase (PG-C), in SHR kidneys during development. PG-C antigenicity increased from 4 to 15 weeks in both SHRs and Wistar Kyoto normotensive rats. However, in agreement with our previous in vitro data no difference in PG-C was observed between strains at any age.