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Biomedical subjects

W J Dodds

Publications and source records attributed to W J Dodds.

At least 91 records · Page 5Linked to original sources
PubMed1990

Radiologic imaging of splenic anomalies.

Knowledge of the anatomy, embryology, and congenital anomalies of the spleen is needed in order to avoid pitfalls in the interpretation of abdominal imaging studies such as CT and sonography. For this reason, this pictorial essay illustrates the anatomy, embryology, and radiologic images of congenital anomalies of the spleen.

Adult↗
PubMed1990

Gastrointestinal lipomas: a radiologic and pathologic review.

Lipomas of the gastrointestinal tract are an infrequent finding on radiologic examination; however, they occur often enough to warrant consideration in the differential diagnosis of mass lesions of the gut. In many instances, their morphologic characteristics allow the specific diagnosis of a lipoma. In this report, we review gastrointestinal lipomas with an emphasis on their radiologic and pathologic correlation.

Gastrointestinal Neoplasms↗
PubMed1990

Effect of bolus volume and consistency on swallow-induced submental and infrahyoid electromyographic activity.

1. The effect of the volume of swallowed bolus and the form of barium delivered (liquid vs paste) on the timing of bolus transit, submental and infrahyoid electromyographic activity and hyoid movement during the oral and pharyngeal phase of swallowing was studied in 9 healthy volunteers. Using videofluoroscopy, we recorded concurrent submental electromyographic (EMG) activity from over the mylohyoid, geniohyoid and anterior digastric muscle complex (SM EMG) and from over the infrahyoid muscles, which consisted mainly of the thyrohyoids (IH EMG). 2. Bolus volume (2 to 20 ml) did not change the timing or the duration of SM EMG and IH EMG activity, transit of the bolus tail through the mouth and pharynx, or the onset and duration of hyoid movement, for either liquid or paste. 3. Although not volume dependent, the magnitude of SM EMG (2 ml, 79 +/- 9% vs 44 +/- 6%, mean +/- SEM) and IH EMG (2 ml, 73 +/- 15% vs 42 +/- 8%) was greater for barium paste than for liquid barium. 4. Large bolus volumes increased the duration of barium flow through the upper esophageal sphincter (UES), for both liquid (0.30 s, 0.40 s, 0.46 s, 0.50 s for 2, 5, 10, 20 ml) and paste (0.32 s, 0.43 s, 0.53 s, 0.61 s for 2, 5, 10, 20 ml).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

The efficacy of endoscopic sphincterotomy after cholecystectomy in patients with sphincter-of-Oddi dysfunction.

Forty-seven patients thought to have dysfunction of the sphincter of Oddi were randomly assigned to undergo endoscopic sphincterotomy or sham sphincterotomy in a prospective double-blind study. All the patients had pain resembling biliary pain, had previously undergone a cholecystectomy, and had clinical characteristics suggesting biliary obstruction. The patients were randomly assigned to the treatment (n = 23) or nontreatment (n = 24) group before manometric examination of the sphincter of Oddi was performed. Sphincterotomy resulted in improvement in pain scores at one-year follow-up in 10 of 11 patients with elevated sphincter pressure. In contrast, there was improvement in only 3 of 12 patients with elevated basal sphincter pressures who underwent the sham procedure. In patients with normal sphincter pressure, pain scores were similar regardless of treatment. After one year, sphincterotomy was performed in 12 symptomatic patients who had undergone the sham procedure--7 with elevated sphincter pressures and 5 with normal sphincter pressures. Forty patients were followed for four years. Of the 23 patients with increased sphincter pressure, 10 of the original 11 who underwent sphincterotomy remained virtually free of pain; 7 others who subsequently underwent sphincterotomy also benefited from it. Thus, 17 of 18 patients with sphincter-of-Oddi dysfunction verified by manometry benefited from sphincterotomy. In patients with normal sphincter pressure, sphincterotomy was no more beneficial than sham therapy. Our observations suggest that endoscopic sphincterotomy offers long-term relief of pain in a group of patients with verified sphincter-of-Oddi dysfunction.

Ampulla of Vater↗
PubMed1989

Timing of videofluoroscopic, manometric events, and bolus transit during the oral and pharyngeal phases of swallowing.

The aims of this study were to evaluate and quantify the timing of events associated with the oral and pharyngeal phases of liquid swallows. For this purpose, we recorded 0-20 ml barium swallows in three groups of volunteers using videoradiographic, electromyographic, and manometric methods. The study findings indicated that a leading complex of tongue tip and tongue base movement as well as onset of superior hyoid movement and mylohyoid myoelectric activity occurred in a tight temporal relationship at the inception of swallowing. Two distinct general types of normal swallows were observed. The common "incisor-type" swallow began with the bolus positioned on the tongue with the tongue tip pressed against the upper incisors and maxillary alveolar ridge. At the onset of the "dipper-type" swallow the bolus was located beneath the anterior tongue and the tongue tip scooped the bolus to a supralingual location. Beginning with tongue-tip peristaltic movement at the upper incisors, the two swallow types were identical. Swallow events that occurred after lingual peristaltic movement at the maxillary incisors showed a volume-dependent forward migration in time that led to earlier movement of the hyoid and larynx as well as earlier opening of the upper esophageal sphincter in order to receive the large boluses that arrived sooner in the pharynx during the swallow sequence than did smaller boluses. The study findings indicated that timing of swallow events should be considered in reference to both swallow type and bolus volume. The findings also indicated an important distinction between peristaltic transit and bolus clearance.

Adolescent↗
PubMed1989

Effect of Desmopresssin in Normal Dogs and Dogs with von Willebrand's Disease.

Desmopressin acetate (DDAVP(R)), a synthetic analogue of vasopressin was slowly administered intravenously to 12 healthy dogs of various breeds and 10 Doberman Pinschers with mild-to-moderate type I von Willebrand's disease at a dose of 0.3, 1.0 and 3.0 micro g/kg body weight. Plasma von Willebrand factor:antigen was measured by an electroimmunoassay prior to and 30, 60, 90, 120 and 180 minutes after desmopressin infusion. Desmopressin induced only very modest and statistically insignificant increases in von Willebrand factor in both groups. We conclude that the response to desmopressin as measured by circulating von Willebrand factor is much less pronounced in healthy dogs and in Doberman Pinschers with von Willebrand's disease than in humans.

Journal Article↗
PubMed1989

Cholinergic control of smooth muscle peristalsis in the cat esophagus.

The aim of this study was to examine in detail the effects of selective cholinergic and other pharmacological antagonists on primary and secondary peristalsis in the smooth muscle of the cat esophagus in order to fully characterize the cholinergic contribution to peristalsis in this species. Primary and secondary peristalsis in the smooth muscle part of the feline esophagus was completely abolished by atropine, 4-dephenylacetoxy-N-methylpiperidine methiodide (4-DAMP) (a selective M2 muscarinic antagonist), hexamethonium, and high doses of nicotine. Pirenzepine (a selective M1 muscarinic antagonist), propranolol, and phentolamine were without effect, as were naloxone, methysergide, and pyrilamine. From these findings we conclude that primary and secondary peristalsis in feline esophageal smooth muscle involves nicotinic ganglionic neurotransmission as well as postganglionic release of acetylcholine that acts directly on muscarinic receptors located on the smooth muscle. Peristalsis in esophageal striated muscle does not involve either synaptic transmission or muscarinic receptors.

Animals↗
PubMed1989

Opening mechanisms of the human upper esophageal sphincter.

Our goals in this study were to evaluate the mechanisms operative in swallow-associated opening of the upper esophageal sphincter (UES) and to determine the dynamics of fluid flow across the sphincter. For this purpose, we obtained concurrent videofluorographic and manometric studies of 2- to 30-ml barium swallows in 15 normal subjects. We found that the resting UES high-pressure zone corresponded closely with the location of the cricopharyngeus. The findings indicated that manometric UES relaxation and anterior hyoid traction on the larynx invariably preceded UES opening. With graded increases in bolus volume, progressive increases occurred in UES diameter, cross-sectional area, flow duration, and transsphincteric flow rate. Intrabolus pressure upstream to the UES and within the UES at its opening during transsphincteric flow of barium remained within a narrow physiological range of less than 10 mmHg up to a bolus volume of 10 ml. With increases in bolus volume, anterior hyoid movement, UES relaxation, and UES opening occurred sooner in the swallow sequence to accommodate the early entry of large boluses into the pharynx. We conclude that during swallowing 1) normal UES opening involves sphincter relaxation, anterior laryngeal traction, and intrabolus pressure, 2) volume-dependent adaptive changes in UES dimension accommodate large bolus volumes and flow rates with minimal requirement for increases in upstream, or intrasphincteric, intrabolus pressure or UES opening duration, and 3) volume-dependent changes in UES dimensions as well as timing of UES relaxation and opening indicate a sensory feedback mechanism that modulates some components of the swallow response generated by the brain stem swallow centers.

Adult↗
PubMed1989

Intramural neural control of opossum sphincter of Oddi.

We evaluated the intramural neural control of the opossum sphincter of Oddi (SO) in an in vitro preparation. Force transducers were used to record contractions at four sites along the sphincter segment. To stimulate intramural nerves, 10- to 120-s trains of pulses (4-10 V amplitude, 0.5 ms duration, and 5 Hz frequency) were delivered to one of three electrode pairs implanted along the SO. Electrical stimulation in the proximal, mid, or distal SO elicited phasic contractions that invariably originated in the proximal SO and propagated antegrade along the entire length of the sphincter segment. Stimulus-evoked contractions resembled spontaneous antegrade peristaltic contractions, but occurred at a higher rate (12-20/min). Atropine completely blocked this excitatory response to nerve stimulation. After atropine, nerve stimulation in the proximal, mid, or distal SO abolished spontaneous contractions at and distal to the site of stimulation for the duration of the stimulus. The inhibitory response to nerve stimulation was completely blocked by tetrodotoxin but was unaffected by phenoxybenzamine, tolazoline, or propranolol. We conclude that 1) the opossum SO is innervated by intramural cholinergic excitatory nerves and nonadrenergic noncholinergic inhibitory nerves; 2) cholinergic excitatory nerves are organized in ascending neural pathways, whereas nonadrenergic noncholinergic inhibitory nerves descend along the length of the SO; and 3) these neural pathways may modulate SO peristalsis in vivo and participate in ascending excitatory and descending inhibitory reflexes.

Ampulla of Vater↗
PubMed1989

Alimentary tract lesions in Cowden's disease.

Cowden's disease was first recognized by its striking dermatological manifestations and subsequently by the increased incidence of neoplastic involvement of the thyroid and breast. Two cases of Cowden's disease with gastrointestinal polyps are presented to illustrate the alimentary tract involvement in this syndrome, gastrointestinal tract involvement with polyposis being seen in at least 50% of cases. As opposed to the more serious potential of neoplasia in the thyroid and breast, involvement of the alimentary tract has negligible clinical impact to the patient.

Adult↗
PubMed1989

Choledochal cyst: findings on cholangiopancreatography with emphasis on ectasia of the common channel.

Choledochal cyst is a congenital malformation of the biliary tree that is unusual but by no means rare. During a 13-year period, we encountered eight patients with choledochal cysts who were evaluated with cholangiopancreatography. All of our cases showed an anomalous union of the pancreatic duct and common bile duct, resulting in a long common channel. Review of cholangiopancreatograms also showed ectasia of the common channel in six of the eight patients. Mean length of the common channel, corrected for magnification, was 26 mm (normal, less than 15 mm). The mean corrected diameter of the common channel was 7 mm (normal, 3-5 mm). We conclude that ectasia of the common channel is an important additional radiographic observation in the diagnosis of choledochal cyst. This observation has not been emphasized before.

Adolescent↗
PubMed1989

The effect of high- vs low-density barium preparations on the quantitative features of swallowing.

We compared the effect of high-density and low-density barium preparations on the quantitative features of swallowing. The two barium preparations differed primarily in density but also differed somewhat in viscosity. Concurrent videofluoroscopic and manometric studies were done in nine healthy control subjects. Videofluoroscopy was recorded in the lateral projection at 30 frames/sec while concurrent manometry was done with five intraluminal transducers that straddled the pharynx and upper esophageal sphincter. Swallows of 5 and 10 ml of high- and low-density barium preparations were recorded. Analysis indicated that, compared with the low-density barium (1.4 g/cm3), the high-density barium (2.5 g/cm3) preparation had a slower oral and pharyngeal bolus transit time and caused significant quantitative differences in the function of the upper esophageal sphincter. Compared with low-density barium boluses, the high-density barium boluses were associated with later sphincter opening and closure, longer duration of sphincter opening and flow, lower flow rate, greater maximal anterior hyoid movement, greater sagittal sphincter diameter, and higher intrabolus pressure upstream of and within the sphincter. We conclude that the density as well as the viscosity of the barium preparation used in radiologic examination of the oral-pharyngeal phases of swallowing has an influence on bolus transit time through the mouth and pharynx, and on the quantitative features of upper esophageal sphincter opening. Although these quantitative differences cannot generally be recognized visually at fluoroscopy, they become important for the quantitative assessment of swallowing in patients with suspected disorders of oral-pharyngeal swallowing. Therefore, the basic barium preparations used to examine such patients should be either standardized or at least specified.

Adult↗