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Biomedical subjects

W J Dodds

Publications and source records attributed to W J Dodds.

At least 109 records · Page 6Linked to original sources
PubMed1989

Tipper and dipper types of oral swallows.

We characterized the normal patterns relating to the onset of the oral-swallowing phase in patients with normal oral motor function. The main pattern of swallowing was of the tipper type, in which swallowing is initiated with the tip of the tongue against the incisors and the bolus is in a supralingual position. However, a second pattern of a dipper-type swallow occurred, in which part of the bolus initially is positioned beneath the anterior part of the tongue. This circumstance requires that the tongue dip beneath the bolus in order to elevate the bolus above the tongue. Dipper swallows occurred in all age groups, but were more prevalent in subjects 60 years or older. Recognition of this component in normal swallowing patterns is essential for optimal evaluation of normal subjects and patients with an abnormal oral phase of swallowing.

Barium Sulfate↗
PubMed1989

Absence of an upper esophageal sphincter response to acid reflux.

Manometric studies of the upper esophageal sphincter (UES) were done on 17 volunteer subjects and 16 patients with endoscopically evident esophagitis. Subjects entered one or both of two protocols designed to assess the effect of esophageal acid exposure on UES pressure. In protocol 1, continuous 3-h postprandial recordings were obtained; a modified sleeve sensor was used to measure UES pressure, and an intraluminal pH electrode was used to detect occurrences of spontaneous gastroesophageal acid reflux. In protocol 2, UES pressure was continuously monitored during a 10-min control period, followed by a 25-min period of esophageal perfusion with 0.1 N HCl. Our findings were that: 1) basal UES pressure measured during the 3-h recording was similar in the normal volunteers and in the group of patients with esophagitis, 2) episodes of spontaneous gastroesophageal acid reflux were not associated with a change in UES pressure in either the normal volunteers or in the patients with esophagitis, and 3) esophageal perfusion with HCl did not affect the UES pressure in either group, although severe heartburn occurred in most of the esophagitis patients. We conclude that the upper esophageal sphincter exhibits normal basal pressure in patients with esophagitis and that esophageal acid exposure, either spontaneous or experimental, does not affect UES pressure in normal volunteers or in patients with esophagitis.

Adult↗
PubMed1988

Hemophilia A in a female dog.

Hemophilia A was diagnosed in a mixed-breed female dog with an acute bleeding disorder. Coagulation factor analysis was used to determine low factor VII-coagulant activity in the dog. Hemophilia A is an X chromosome-linked recessive trait that has not been reported as a cause of disease in female dogs.

Animals↗
PubMed1988

Effects of reagent and instrument on prothrombin times, activated partial thromboplastin times and patient/control ratios.

Activated partial thromboplastin times accumulated from two proficiency testing surveys were analyzed to determine simultaneously the effects of the method and reagent used. Prothrombin time results were reevaluated concomitantly for comparison. A robust two-way analysis of variance was applied to determine the effect of method and reagent on APTT results. The effect of the reagent and method on the ratio of abnormal to normal plasma clotting times was determined. We found a substantial difference in ratios for the PT using different reagents on the same instrument. There was an even larger effect of reagents on APTT ratios. Our finding of substantial reagent effects for the PT and APTT clearly support the need for standardization. We found standardization to be feasible only for the PT, and only if applied in a form consistent with the inherent error structure of the data. For the APTT, the present methodology and plasma samples did not achieve consistent standardization.

Blood Coagulation Tests↗
PubMed1988

Factors that influence induction of gastroesophageal reflux in normal human subjects.

Findings from recent studies indicate that transient relaxation of the lower esophageal sphincter (LES) is an important contributory mechanism to spontaneous episodes of gastroesophageal reflux (GER) in normal subjects as well as in patients with reflux esophagitis. Our study aim was to evaluate the interrelationship between reduction of LES pressure and elevation of intraabdominal pressure in the induction of GER in healthy subjects. Seven volunteers were studied supine after gastric loading with 0.1 N HCl. A pH probe recorded acid GER. Leg raising (LR) or abdominal compression (AC) were used as stress maneuvers to increase intraabdominal pressure, either alone or in combination with stimuli that concurrently lowered LES pressure, namely multiple rapid swallows (RS) or intraesophageal balloon distention (BD). Each individual stimulus and stimulus combination was tested three times, giving a total of 24 test maneuvers per subject. The test maneuvers elicited 2-12 GERs in each subject. The GER incidence for single maneuvers was: AC, 0%; LR, 0%; RS, 19%; and BD, 24%. LR in combination with RS or BD did not increase the incidence of GER above that induced by RS or BD alone. In contrast, AC concurrent with RS and BD increased the incidence of GER to 52% and 81%, respectively. For all test conditions, a prerequisite for the occurrence of GER was a fall in LES pressure to a minimal value of 3 mm Hg or less. GER never occurred when LES pressure was greater than or equal to 4 mm Hg, even during intervals of increased intraabdominal pressure.(ABSTRACT TRUNCATED AT 250 WORDS)

Abdomen↗
PubMed1988

Effect of vagotomy on biliary-tract motor activity in the opossum.

In this study, we evaluated the effect of truncal vagotomy in the opossum on changes in gallbladder and sphincter-of-Oddi (SO) contractile activity that occur normally during fasting and after a meal. In six animals, bipolar electrodes were implanted on the SO, gastric antrum, duodenum, and jejunum. A catheter secured in the gallbladder fundus was used to monitor gallbladder volume. After control studies, truncal vagotomy and pyloroplasty were done in each animal. Before vagotomy, the SO exhibited cyclic changes in spike-burst rate, from 2 to 5/min, that were synchronized with corresponding phases of the duodenal MMC cycle. The gallbladder exhibited partial emptying during the second half of the duodenal MMC cycle with refilling during the first half of the next cycle. By two weeks after vagotomy, the MMC-related changes in SO and gallbladder contractile activity were normal. In contrast, vagotomy retarded the increase in SO spike-burst rate and delayed as well as diminished the pronounced gallbladder emptying that normally occurs after a meal. The same effects were observed for changes in SO and gallbladder activity induced by intraduodenal infusion of Isocal. After vagotomy, the SO and gallbladder exhibited exaggerated responses to intravenous infusion of CCK-OP or motilin. We conclude that truncal vagotomy in the opossum does not affect the fasting pattern of SO and gallbladder contractile activity, but it significantly alters the normal postprandial pattern of enhanced SO spike-burst rate and pronounced gallbladder emptying. The precise mechanism(s) whereby vagotomy produces these changes remains to be determined.

Action Potentials↗
PubMed1988

Complement C5a (desArg) generation in serum exposed to damaged aortic endothelium.

Complement activation by injured endothelial cells was investigated using ex vivo rabbit thoracic aortas as a source of endothelium and a neutrophil aggregation (NA) bioassay to detect the complement cleavage product C5a (desArg). Endothelium, oxygen-starved by incubating aortas 30 min with Tyrode's buffer, activated complement as demonstrated by a 57% increase in the NA response induced by serum from buffer-treated aortas as compared to serum from untreated control aortas. Incubation of MgEGTA serum in injured aortas resulted in a 27% (P less than 0.025) weaker NA response than normal serum, indicating participation by both classical and alternative pathways of complement activation. Serum from aortas incubated 30 min with 100 micrograms/ml cholestane-3 beta, 5 alpha, 6 beta-triol, a cytotoxic cholesterol oxidation derivative, induced a NA response comparable to that from serum from aortas treated 30 min with Tyrode's buffer. Heat inactivation of serum prior to aortic incubation abolished NA activity and serum incubated in deendothelialized aortas lacked NA activity. Fractionation of serum samples from these experiments on Sephadex G-100 revealed a single peak of NA activity corresponding to the molecular weight of C5a (desArg). Endothelial cell injury was demonstrated by the inability to exclude Trypan blue dye and by scanning electron microscopy. These data demonstrate that damaged arterial endothelium can effectively activate the complement system, resulting in the production of an anaphylatoxic inflammatory mediator.

Animals↗
PubMed1988

Gastroduodenal regulation of common duct bile flow in the dog.

We investigated the relationship between the entry of individual drops of bile into the duodenum and gastroduodenal motor activity in the fasted state in 10 conscious dogs. The common bile duct was transected and a catheter was inserted through each end. The exteriorized catheters were connected to a photometric drop-flow meter. During phase III activity, bile entered the duodenum in single drops, only in between two consecutive contractions, or as a series of drops during transient inhibition of duodenal contractions by antral phase III contractions. During phase II activity bile also entered the duodenum, usually in between contractions or when the duodenum was intermittently quiescent. Bile entered the duodenum during a duodenal contraction only when the contraction amplitude was less than 15% +/- 1% (mean +/- SE) of the maximal amplitude during phase III contractions. Bile flow into the duodenum showed a cyclic pattern with a peak during late duodenal phase II activity and a trough during duodenal phase I activity only when phase III activity originated in the duodenum and migrated caudad. There was no cyclic pattern of bile flow when phase III activity originated in the proximal jejunum and migrated caudad. The total volume of bile flow in a migrating motor complex cycle and bile flow rate were greater when phase III activity started in the proximal jejunum than when it started in the duodenum. We conclude that gastroduodenal contractions play an important role in the regulation of bile flow into the duodenum. The cyclic pattern of bile flow is altered when phase III activity starts ectopically in the jejunum.

Animals↗
PubMed1988

Efficacy of quantitative hepatobiliary scintigraphy and fatty-meal sonography for evaluating patients with suspected partial common duct obstruction.

In this study we evaluated by blinded design the diagnostic efficacy of two noninvasive techniques, quantitative hepatobiliary scintigraphy (QHS) and fatty-meal sonography (FMS), for evaluating patients with suspected partial common duct obstruction. Quantitative hepatobiliary scintigraphy was performed on 56 cholecystectomized individuals (22 asymptomatic controls, 28 patients with suspected partial common duct obstruction, and 6 nonjaundiced cirrhotics) and FMS was done in 51 cases. For QHS, time-activity curves were generated for regions of interest over the liver, hepatic hilum, and common duct. For FMS, we measured common duct diameter before and 45 min after a fatty meal (Lipomul, 1.5 ml/kg). Each of the 28 patients with suspected partial common duct obstruction and 6 cirrhotic patients underwent endoscopic retrograde cholangiography, often accompanied by sphincter of Oddi manometry. Findings from these examinations were taken as the gold standard to determine the presence or absence of conditions that could account for intermittent symptomatic partial common duct obstruction. The most sensitive indicators for a positive test were a 45-min isotope clearance of less than 63% for QHS and a common duct increase of greater than or equal to 2 mm after the fatty meal for FMS. Of 28 patients with suspected partial common duct obstruction, 15 were judged to be true-positive and 13 true-negative. The 6 cirrhotic patients were without common duct obstruction. The study findings showed that each test had a 67% sensitivity that improved to 80% when the findings from both test results were combined. The specificity of QHS was 85% and that of FMS was 100%. All 6 cirrhotic patients had negative findings on FMS and 4 were false-positive on QHS. The true-positives included 8 patients with a small common duct stone and 6 with obstructive sphincter of Oddi dysfunction (4 stenosis, 2 dyskinesia). We conclude that noninvasive QHS and FMS afford good sensitivity and specificity for evaluating cholecystectomized patients with suspected partial common duct obstruction.

Adult↗
PubMed1988

Upper esophageal sphincter function during deglutition.

Upper esophageal sphincter function was investigated during swallows of graded volumes in 8 normal volunteers. Concurrent recordings of video-fluoroscopic and manometric studies were obtained and correlated with each other by means of a videotimer. Maximal upper esophageal sphincter (UES) pressure was typically located 1.5 cm distal to the air-tissue interface between the hypopharynx and the proximal margin of the sphincter. The region in which UES pressure was greater than or equal to 50% maximal averaged 1.0 cm in length. Thus, the physiologic high-pressure zone of the UES corresponds in size and location to that of the cricopharyngeus muscle. Fluoroscopic analysis of sphincter movement indicated that the sphincter high-pressure zone moved 2.0-2.5 cm orally during swallowing and that the magnitude of the orad movement was directly related to the volume of barium swallowed. The maximal anterior-posterior diameter of sphincter opening during a swallow ranged from 0.9 to 1.5 cm and was also directly related to the volume swallowed. The intervals of UES opening and relaxation increased significantly with increasing bolus volume; the duration of UES relaxation ranged from a mean of 0.37 s for dry swallows to 0.65 s for 20-ml swallows. Thus, the dynamics of UES function during deglutition are dependent upon the volume of the swallowed bolus. Larger bolus volumes are accommodated by both an increased diameter of sphincter opening and by prolongation of the interval of sphincter relaxation. Analysis of the timing of other reference points within the pharyngeal swallow sequence indicated that as the manometric interval of UES relaxation increased, the period of laryngeal elevation was prolonged, the UES relaxed earlier and contracted later, and the interval between the onset of laryngeal elevation and hypopharyngeal contraction increased.

Adolescent↗
PubMed1988

Effect of peristaltic dysfunction on esophageal volume clearance.

Prolonged esophageal acid clearance, found in some patients with esophagitis, can be attributed in part to the peristaltic dysfunction observed in this population. In this study, we undertook to define the effect of commonly observed peristaltic dysfunction on volume clearance by obtaining concurrent videofluoroscopic and manometric recordings in patients with nonobstructive dysphagia or heartburn. Excellent correlation existed between the findings from the two studies. A single normal peristaltic wave resulted in 100% clearance of a barium bolus from the esophagus. At each recording site, luminal closure, as demonstrated by videofluoroscopy, coincided with the upstroke of the peristaltic pressure complex. Absent or incomplete peristaltic contractions invariably resulted in little or no volume clearance from the involved segment. Regional hypotensive peristalsis was associated with incomplete volume clearance by the mechanism of retrograde escape of barium through the region of hypotensive contraction. The regional peristaltic amplitude required to prevent retrograde escape of barium was greater in the distal compared with the proximal esophagus. The mean peristaltic amplitude associated with instances of retrograde escape was 25 mmHg in the distal esophagus compared with 12 mmHg in the proximal esophageal segments. Thus, the peristaltic dysfunction commonly seen in patients with esophagitis (failed and hypotensive peristalsis) likely leads to impaired volume clearance.

Adult↗
PubMed1988

Computed tomography examination of periampullary neoplasms.

The hospital records of 24 patients with periampullary neoplasms were reviewed. The clinical triad of jaundice, pain, and weight loss and the radiographic imaging triad of dilated biliary ducts, dilated pancreatic duct, and periampullary mass should suggest the diagnosis of periampullary neoplasm.

Adenocarcinoma↗
PubMed1988

Computed tomography characteristics of intermesenteric hematomas.

Abdominal bleeding may accumulate in the peritoneal cavity, retroperitoneal compartments, intraabdominal organs such as liver or bowel wall, or, rarely, in the intestinal mesentery. During the past 3 years we have encountered four cases of isolated mesenteric hematomas that were demonstrated on abdominal computed tomography examination. In this report, we present the clinical and computed tomography findings of intermesenteric hematomas with review of the pertinent mesenteric anatomy, and add four more cases to the two cases reported in two earlier reports.

Abdominal Injuries↗
PubMed1988

Hereditary and acquired thrombopathias.

Normal platelet function is essential for hemostasis. The pathophysiologic processes that result in acquired quantitative platelet abnormalities are detailed. Platelet pathophysiology associated with acquired qualitative disorders, either drug-induced or secondary to disease, is discussed. Numerous hereditary platelet defects also exist. Their functional and biochemical features are presented.

Animals↗
PubMed1988

Clinical experience in 82 patients with pancreas divisum: preliminary results of manometry and endoscopic therapy.

Although it is clear that the majority of patients with pancreas divisum have no clinical disease, there is a subset of patients who have either unexplained abdominal pain or recurrent pancreatitis. Endoscopic therapy of the minor papilla may alter the clinical course of those patients with pancreas divisum and recurrent pancreatitis. Manometric study of the minor papilla is feasible and reveals a sphincter mechanism similar to the major papilla. Clinical response to endoscopic therapy may aid in selecting patients who might benefit from surgical sphincteroplasty. Refinement of manometric study of the minor papilla offers a potential method of detecting functional obstruction of dorsal duct drainage.

Adolescent↗