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Biomedical subjects

W L Smith

Publications and source records attributed to W L Smith.

At least 253 records · Page 14Linked to original sources
PubMed1988

Balloon dilatation of esophageal stenosis in children.

Balloon dilatation of benign esophageal strictures is an accepted mode of therapy in adults. This report describes balloon dilatation in 20 consecutive infants and children. The lesions treated include 11 strictures at surgical anastomotic sites, seven restrictive Nissen fundoplications, and three nonanastomotic esophageal strictures. One patient had two lesions. Most dilatations were performed on an outpatient basis without anesthesia. All strictures responded immediately to dilatation. In most cases, long-term resolution occurred after three or fewer procedures. A subgroup of patients was identified in which a prolonged course of treatment was needed. These included patients with long strictures due to esophageal atresia, patients with chronic severe esophagitis, and patients with strictures at the site of esophageal perforation. No significant complications were encountered. Balloon dilatation of esophageal stenosis in children is effective and safe and should be considered before other methods of treatment are used.

Catheterization↗
PubMed1987

Immunochemical and kinetic evidence for two different prostaglandin H-prostaglandin E isomerases in sheep vesicular gland microsomes.

Splenic lymphocytes from mice immunized with a partially purified prostaglandin (PG) H-PGE isomerase from sheep vesicular glands were fused with SP2/0-Ag14 myeloma cells. Two spleen cell-myeloma hybrids (hei-7 and hei-26) were selected and cloned. The mouse antibodies secreted by the two hybrids, IgG1 (hei-7) and IgG1 (hei-26), caused immunoprecipitation of a maximum of 45 and 22%, respectively, of the solubilized PGH-PGE isomerase activity of sheep vesicular gland; immunoprecipitation of activity by the two antibodies was additive. The antigens reactive with IgG1 (hei-7) and IgG1 (hei-26) were identified as proteins with Mr = 17,500 and 180,000, respectively, by Western transfer blotting or sodium dodecyl sulfate-polyacrylamide gel electrophoresis of immunoprecipitated 125I-labeled microsomes. The PGH-PGE isomerase activities precipitated by IgG1 (hei-7) and IgG1 (hei-26) exhibited different kinetic properties with respect to time course, Km for PGH2, and concentration dependence for GSH. No significant GSH-S-transferase activity was present in these immunoprecipitates. These data indicate that there are at least two different proteins in sheep vesicular gland microsomes capable of catalyzing GSH-dependent PGH-PGE isomerase reactions. IgG1 (hei-7), but not IgG1 (hei-26), caused coprecipitation of PGH synthase and PGH-PGE isomerase activities when incubated with intact right-side-out vesicular gland microsomes. Thus, the epitope for IgG1 (hei-7) is located on the cytoplasmic surface of those microsomal spheres which contain PGH synthase. This latter finding suggests that the isomerase reactive with IgG1 (hei-7) is involved in PGE synthesis in sheep vesicular glands.

Animals↗
PubMed1987

Dominantly inherited dilated cardiomyopathy.

We describe a family in which there is segregating an autosomal dominant gene determining a cardiomyopathy. The pathodynamics is that of pump failure associated with dilatation of the heart, generally having an overt clinical onset from the fourth through seventh decades. Dysrhythmia is a frequent concomitant feature. There may be an associated skeletal myopathy, either producing a very mild proximal weakness or proving detectable only upon biopsy. This family is similar to other reported cases of familial dominant "idiopathic" dilated cardiomyopathy, but the nature of the heterogeneity within this category remains to be elucidated. The roles of echocardiography, cardiac biopsy, and skeletal muscle biopsy in the presymptomatic detection of the heterozygote are noted.

Adolescent↗
PubMed1987

Magnetic resonance imaging of children with Duchenne muscular dystrophy.

Eight children representing a spectrum of clinical states of biopsy-proven Duchenne muscular dystrophy (DMD) underwent magnetic resonance (MR) scans to assess the degree of muscular involvement and disease progression. Five muscle groups (neck, shoulder girdle, pelvic girdle, thigh and calf) were evaluated. In each case, involved muscles were clearly demarcated. Image estimates of disease severity by degree of muscle involvement correlated well with clinical staging. In our experience MR is useful for assessment of disease stage, selection of appropriate muscles for biopsy and planning for courses of physical and rehabilitation therapy.

Adipose Tissue↗
PubMed1987

Curriculum topics in radiology education.

There is a need for a standardized curriculum for medical school instruction in diagnostic radiology. A survey of clinicians, recent medical school graduates, and educators in radiology resulted in remarkable agreement as to the clinical curriculum topics considered important in a medical school course in diagnostic radiology. This report outlines these topics and discusses both their commonality and their differences.

Education, Medical, Graduate↗
PubMed1987

Critical analysis of radiologist-patient interaction.

A critical incident interview technique was used to identify features of radiologist-patient interactions considered effective and ineffective by patients. During structured interviews with 35 radiology patients and five patients' parents, three general categories of physician behavior were described: attention to patient comfort, explanation of procedure and results, and interpersonal sensitivity. The findings indicated that patients are sensitive to physicians' interpersonal styles and that they want physicians to explain procedures and results in an understandable manner and to monitor their well-being during procedures. The sample size of the study is small; thus further confirmation is needed. However, the implications for training residents and practicing radiologists in these behaviors are important in the current competitive medical milieu.

Consumer Behavior↗
PubMed1987

Cine CT of the mediastinum in pediatric patients.

Cine computed tomographic (CT) examinations of the mediastinum were performed in 83 pediatric patients. Lesions imaged include neoplastic, inflammatory, and vascular abnormalities. The 50-msec scan time of cine CT provides for superb depiction of the heart and airway, minimizes motion artifact, allows examinations to be done with little or no sedation, and permits optimal opacification of all vascular structures with as little as 0.5 mL of intravenously administered contrast medium per kg of body weight. Scanning time for an examination in which images in 20 sections are obtained is approximately 10 seconds. Radiation dose is significantly lower than that in comparable CT or plain radiographic studies. Preliminary experience shows cine CT to be an excellent imaging modality for the examination of the mediastinum in children.

Adolescent↗
PubMed1987

A1 and A2 adenosine receptors in rabbit cortical collecting tubule cells. Modulation of hormone-stimulated cAMP.

Adenosine analogs were used to investigate the cellular mechanisms by which adenosine may alter renal tubular function. Cultured rabbit cortical collecting tubule (RCCT) cells, isolated by immunodissection, were treated with 5'-N-ethylcarboxamideadenosine (NECA), N6-cyclohexyladenosine (CHA), and R-N6-phenylisopropyladenosine (PIA). All three analogs produced both dose-dependent inhibition and stimulation of RCCT cell cyclic AMP (cAMP) production. Stimulation of cAMP accumulation occurred at analog concentrations of 0.1 microM to 100 microM with the rank order of potency NECA greater than PIA greater than CHA. Inhibition occurred at concentrations of 1 nM to 1 microM with the rank order of potency CHA greater than PIA greater than NECA. These effects on cAMP production were inhibited by 1,3-diethyl-8-phenylxanthine and isobutylmethylxanthine. CHA (50 nM) blunted AVP- and isoproterenol-stimulated cAMP accumulation. This modulation of hormone-induced cAMP production was abolished by pretreatment of RCCT cells with pertussis toxin. Prostaglandin E2 production was unaffected by 0.1 mM CHA. These findings indicate the presence of both inhibitory (A1) and stimulatory (A2) receptors for adenosine in RCCT cells. Moreover, occupancy of the A1 receptor causes inhibition of both basal and hormone-stimulated cAMP formation through an action on the inhibitory guanine nucleotide-binding regulatory component, Ni, of the adenylate cyclase system.

1-Methyl-3-isobutylxanthine↗
PubMed1987

Prostaglandin endoperoxide synthase in rat ovarian follicles: content, cellular distribution, and evidence for hormonal induction preceding ovulation.

These studies were undertaken to determine if the content of prostaglandin endoperoxide (PGH) synthase (PGS) was regulated in rat ovarian follicles in a time-, tissue-, and dose-dependent manner. For quantitation and localization of the enzyme by immunoblot and immunofluorescent analyses, respectively, a polyclonal antibody to highly purified (95%) ovine seminal vesicle PGS [mol wt, (Mr), 72,000] was generated in a rabbit, and an immunoglobulin G fraction of the antiserum was purified by elution from a PGS affinity resin. Soluble cell extracts were prepared from: 1) small antral (SA) and preovulatory (PO) rat follicles before and at selected time intervals after exposure to increasing doses (0.25-10.0 IU) of hCG, 2) granulosa and thecal cells of these same follicles, and 3) granulosa cells of hypophysectomized (H) rats before and after treatment with estradiol (HE), estradiol and FSH (HEF), and 10 IU hCG. Immunoblot analyses demonstrated that the content of PGS (Mr, 72,000) was low (negligible) in granulosa and thecal cells of SA and PO follicles, was induced preferentially (approximately 15-fold) in granulosa cells between 1 and 7 h after hCG treatment (0.5, 2.0, or 10 IU), and declined between 12-24 h after administration of 10 IU hCG, reaching undetectable amounts in corpora lutea isolated 48 h after hCG treatment. PGS (Mr, 72,000) was also induced by 10 IU hCG in granulosa cells of HEF rats, but was low in granulosa cells of H, HE, and HEF rats. In contrast, prostacyclin synthase was present in granulosa cells of preantral (H and HE rats), SA, and PO follicles, was not induced by hCG, and was highest in thecal cells. Immunofluorescent analyses confirmed both the tissue-specific localization and induction of PGS in granulosa cells of rat PO follicles treated with 10 IU hCG and the subcellular fractionation analyses showing that the PGS that was induced by hCG was localized primarily to a membrane (plasma membrane?) fraction of granulosa cells. Immunofluorescent data also demonstrated immunoreactive PGS in the vascular tissue of the rat corpus luteum but not in the luteal cells. Results of these studies document unequivocally that the synthesis of prostaglandins that is increased by LH/hCG in rats preceding ovulation is associated with an increased PGS content, that induction of the induced enzyme is transient, and that the enzyme is primarily localized to granulosa cell membrane fractions.

Animals↗
PubMed1987

Chronic airway obstruction in children: evaluation with cine-CT.

The radiographic diagnosis of airway lesions, especially laryngomalacia and tracheomalacia, often is imprecise. Endoscopy, which allows detailed examination of the upper airway, is an invasive procedure requiring sedation or anesthesia. A prospective study was undertaken to show the value of cine-CT (Imatron) scanning in diagnosing airway lesions in children. Eleven patients, aged 10 days to 4 years old, with a history of stridor were evaluated by both cine-CT and flexible fiberoptic endoscopy. Cine-CT studies of 12 children imaged for other reasons and without clinical evidence of airway disease served as controls to assess normal airway motion. Endoscopy identified 13 abnormalities, 11 of which were identified by cine-CT. Cine-CT has the capacity to image common causes of chronic stridor in children. It is rapid, noninvasive, and requires no sedation in most children. Although additional work is needed to clarify the role of cine-CT, this study suggests that cine-CT is a sensitive and specific imaging technique for evaluation of chronic stridor in infants and children.

Child, Preschool↗
PubMed1987

Growth and metabolism of growing beef calves fed tall fescue haylage supplemented with protein and(or) energy.

Endophyte (Acremonium coenophialum)-infected Kentucky 31 tall fescue was fertilized in mid-August, stockpiled, harvested November 4 to 6 and stored in a concrete stave silo. Ninety-six growing calves (189 kg) were assigned to the following treatments (24 calves/treatment): 1) corn silage (CS) plus .4 kg/d of soybean meal (SBM; 2) fescue haylage plus .4 kg/d of SBM; 3) fescue haylage plus 1.6 kg/d of corn and 4) fescue haylage plus 1.6 kg/d of corn and .4 kg/d of SBM. Daily gains and dry matter (DM) intakes during the 91-d trial were .52, 4.58; .51, 5.22; .59, 6.06; and .63, 6.18 kg for treatments 1 through 4, respectively. Daily gains of calves fed corn silage plus SBM and fescue haylage plus SBM were not different (P greater than .05). However, a difference (P less than .05) existed between treatments 1 and 2 vs 3 and 4. Feed conversion was improved (P less than .05) in calves fed corn silage. Calves in a metabolism trial were fed either 1) 6.2 kg November-ensiled fescue haylage or 2) 6.2 kg November-ensiled fescue haylage plus 1.6 kg/d of corn. Digestibility of DM, N-free extract (NFE) and TDN did not differ (P greater than .05) between treatments. Ether extract digestibility was greater (P less than .05) for the added corn diet, while that of CP was greater (P less than .05) for the fescue haylage diet. Nitrogen retained was higher (P less than .05) for calves fed added corn. A follow-up trial with 96 growing calves (190 kg) compared September- and November-harvested fescue haylages supplemented with either 1.3 or 2.6 kg corn/d.(ABSTRACT TRUNCATED AT 250 WORDS)

Animal Feed↗
PubMed1987

Intestinal motility disorders of infants and children: classification, clinical manifestations and roentgenology.

Diseases affecting intestinal motility in the pediatric age group are reviewed as to pathophysiology, clinical manifestations, and imaging investigation. Acute disease includes classical paralytic ileus (which has unique causes and manifestations in the infant) and acute regional bowel paralysis. Perinatal motility disorders consist of a group of related clinical syndromes which have in common functional intestinal obstruction. Chronic motility disorders are divided into those diseases in which the principal abnormality is in the bowel or those entities where the gut is affected as part of a generalized disease. Regional muscle disease includes Hirschsprung's disease and allied disorders. Some recognized causes of chronic functional obstruction of bowel include megacystis-microcolon-intestinal hypoperistalsis syndrome, rare enzymatic disorders, several discrete forms of chronic intestinal pseudoobstruction, as well as some less well-defined entities. Clinical and pathologic nature and methods of imaging investigation of these entities are considered.

Abdominal Muscles↗
PubMed1987

Application of cine computed tomography to the assessment of velopharyngeal form and function.

The mechanism of velopharyngeal closure is clearly three-dimensional in nature. Numerous attempts have been made to obtain a comprehensive picture of velopharyngeal movement, with varying degrees of success. A computed tomography scan system has recently been developed that may be used for real-time motion study of various body systems. This preliminary study was designed to assess the applicability of multi-level cine computed tomography scanning as a tool in the three-dimensional analysis of the velopharynx. One normal speaker and one speaker with an unrepaired palatal cleft were asked to phonate while serial sections were taken at 650-millisecond intervals through a number of transverse sections in the velopharyngeal region. This paper includes an explanation of cine CT technology, examples of scans on two speakers with clearly different velopharyngeal mechanisms, and discussion of the potential use of cine computed tomography as a tool in the analysis of both normal and disordered velopharyngeal function.

Cineradiography↗