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Biomedical subjects

W L Smith

Publications and source records attributed to W L Smith.

At least 325 records · Page 18Linked to original sources
PubMed1982

Selection of optimal screen-film combination for use in the neonatal intensive care unit.

This report describes evaluation of screen-film combinations for use in the newborn intensive care unit. Since most infant population studies are performed using portable techniques, screen-film combination speeds consistent with those techniques were used. The first phase, a phantom study, was evaluated by nine radiologists from three institutions. A surprising degree of uniformity was noted in their selections of the best system, and their overall selection correlated closely with their assessment of resolution. The screen-film combinations that were rated first and second best were then compared in clinical trials. Both supported the preference expressed in the phantom studies, the first choice system consistently selected as best.

Clinical Trials as Topic↗
PubMed1981

Dominant inheritance of velopharyngeal incompetence.

A family is described in which a girl, two boys and their father showed speech hypernasality. A half-sib, a grandfather, a great-aunt, and a cousin of these sibs also showed a similar speech defect. Analysis of recorded speech of the father and three sibs revealed articulation deficiencies in addition to hypernasality. Intra-oral examination and neurologic evaluation of the cranial nerves failed to reveal any abnormality in palate morphology or cranial nerve function. Psychometric and audiometric studies of the affected did not contribute to an explanation of the defect. Speech cinefluoroscopy and cephalometric radiographs confirmed that the speech defect involved velopharyngeal incompetence resulting from an anatomic disproportion of the velopharyngeal structures. The family pedigree supports the concept that this type of nasal speech, resulting from disproportion of velopharyngeal structures, is transmitted as an autosomal dominant trait.

Adolescent↗
PubMed1981

Efficacy of whole lung tomography in diagnosing metastases from solid tumors in children.

Whole lung, frontal tomography is compared with frontal chest radiography in the diagnosis of pulmonary metastasis in children with cancer. Of 79 patients studied, 65 had a total of 195 routine tomograms. In only 2.7% of studies did tomography yield new information, and in only 1% was an additional lesion visualized. In 27 patients, tomography was performed after an abnormality was seen on the chest radiograph. New information was obtained in 15 (32%) of those 47 studies; additional nodules were identified on six occasions (four metastatic, two inflammatory), but only once was treatment altered. In one study, tomography localized a nodule seen only on a lateral chest radiograph, and in eight studies it excluded metastasis following an abnormal frontal chest radiograph.

Adolescent↗
PubMed1981

Kinin-induced prostaglandin synthesis by renal papillary collecting tubule cells in culture.

Cells having morphological and histochemical properties of collecting tubules were isolated from rabbit renal papillae. Confluent monolayer cultures of these renal papillary collecting tubule (RPCT) cells formed hemicysts and adhered with morphological asymmetry to Millipore filters. Cultures of 1-day-old RPCT cells synthesized cAMP in response to arginine vasopressin (AVP) (half-maximal response to 10(-10) M), oxytocin, and parathyroid hormone (half-maximal responses at 5 X 10(-9) M) but not to adrenergic agents. After 10 days of growth (fourfold increase in cell number) RPCT cells retained the same pattern of histochemical and hormonal responses as 1-day-old cells. Hormones were tested for their influence on the release of immunoreactive prostaglandins (iPG) by RPCT cells; the major product under both basal and stimulated conditions was iPGE2. At very low concentrations (greater than or equal to 10(-10) M), bradykinin, lysyl-bradykinin, and methionyl-lysyl-bradykinin caused four- to sixfold increases in the rate of iPGE2 formation within 3 min; smaller (less than twofold) increases were observed with relatively high concentrations of epinephrine (10(-5) M), norepinephrine (10(-5) M), and angiotensin II (10(-7) M), but only after longer incubations. Significantly, neither AVP (10(-7) M) nor [deamino]AVP (10(-7) M) caused prostaglandin release by RPCT cells. Our results indicate that kinins can act directly on the collecting tubule to elicit PGE2 formation; furthermore, this effect of kinins may be natriuretic, since PGE2 has been shown to inhibit Na+ resorption by the medullary collecting tubule and thick ascending limb.

Animals↗
PubMed1980

Subcellular localization of prostaglandin-forming cyclooxygenase in Swiss mouse 3T3 fibroblasts by electron microscopic immunocytochemistry.

Swiss mouse 3T3 fibroblasts were grown in tissue culture, fixed with lysine-paraformaldehyde-periodate solutions containing 0 to 0.1% Tween 20, and then stained for cyclooxygenase antigenicity using rabbit anti-cyclooxygenase IgG in the peroxidase anti-peroxidase procedure. When examined by light microscopy, those cells fixed in the presence of 0.03 to 0.1% Tween 20 exhibited staining throughout the cytoplasm and around the nucleus but not on the cell surface. No staining occurred when either preimmune IgG or anti-cyclooxygenase IgG adsorbed with purified enzyme was substituted for the immune IgG. Electron microscopic examination of cells treated with fixative containing 0.05% Tween 20 and then stained for cyclooxygenase antigenicity revealed electron-dense deposits on the endoplasmic reticulum and nuclear membrane but not the mitochondrial or plasma membranes. No staining was seen in cells treated with control sera. Agents such as angiotensin II, bradykinin, antidiuretic hormone, and thrombin interact, apparently with the 3T3 cell surface to cause a release of arachidonic acid and prostaglandin E2 formation (Pong, S.S., Hong, S. L., and Levine, L. (1977) J. Biol. Chem. 252, 1408-1413). Our results establish that conversion of arachidonic acid to the prostaglandin endoperoxide precursor of PGE2 actually takes place on the endoplasmic reticulum and the nuclear envelope.

Animals↗
PubMed1980

Paralysis of the small bowel resembling mechanical intestinal obstruction.

In some instances, particularly in the neonate, paralytic ileus affects predominantly the small bowel, thus resembling intestinal obstruction. Localized paralysis of the small bowel occurs secondary to regional events in a segment of gut and resembles mechanical obstruction even more closely. In localized paralysis the bowel lumen is usually dilated without abrupt distal transition to collapsed intestines. If there is radiographic and clinical recognition of localized, transitory bowel paralysis, surgery is usually unnecessary.

Adolescent↗
PubMed1980

Immunocytochemical localization of the prostaglandin-forming cyclooxygenase in the cerebellar cortex.

An indirect immunocytofluorescence technique was used to examine the distribution of the prostaglandin-forming cyclooxygenase in the cerebellar cortex of the pig, guinea, rat, mouse, cow, rabbit and sheep. Cyclooxygenase antigenicity was detected (a) in the cell bodies of Bergman glial cells in the Purkinje cell layer of the porcine, ovine and bovine cerebellar cortex; (b) in small arterioles throughout the cerebellar cortex in the sheep and cow; and (c) in the endothelial cells of large arteries in all the species examined. No cyclooxygenase-positive staining was apparent in neuronal cell bodies of granule, basket, stellate or Purkinje cells. Our results establish that prostaglandin endoperoxides can be synthesized by the arterial vasculature and at least certain glial cells in the central nervous system.

Animals↗
PubMed1980

The use of metrizamide (amipaque) to visualise the gastrointestinal tract in children: a preliminary report.

Metrizamide (amipaque) has not been used previously as a diagnostic contrast agent in the gastrointestinal tract. Metrizamide is a water-soluble isotonic contrast material having many advantages over barium and existing hypertonic water-soluble agents. There are many clinical situations in children in which metrizamide should be the contrast agent of choice for investigating the gastrointestinal tract. Four neonates are presented in whom barium or gastrografin were absolutely contraindicated. In each case metrizamide gave excellent visualization of the gastrointestinal tract. It could be followed through be bowel giving excellent visualisation even up to 120 h after ingestion. No harmful effects were noted in the four cases studied.

Barium Sulfate↗
PubMed1980

Speech changes in cerebral-palsied patients after cerebellar stimulation.

A quantitative study was made of the effects of focal cerebellar stimulation on oral-motor control, duration of phonation, articulation and vocal characteristics in 10 patients with cerebral palsy. The patients were evaluated prior to surgery and again after approximately two and six months of cerebellar stimulation. One patient had normal speech, which was not affected by the stimulation; another case with moderate dysarthria due to severe hearing loss was not helped by the stimulation. Seven patients increased their duration of vowel phonation by about two seconds, a significant amount. Four of the patients with moderate dysarthria improved their articulation, particularly for the consonants S, Sh and Th, after two months of stimulation. Two patients had changes in oral-motor control, which included better tongue and lip movements, and two other cases had small alterations in hypernasality or breathiness. Most of the changes in sound production and speech intelligibility appear to be related to improved intra-oral breath control.

Adolescent↗