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Biomedical subjects

W J Dodds

Publications and source records attributed to W J Dodds.

At least 271 records · Page 15Linked to original sources
PubMed1978

Responses of feline esophagus to cervical vagal stimulation.

We used an in vivo feline model to study striated and smooth-muscle esophageal responses to cervical vagal stimulation (VS). Circular esophageal contractions were measured by intraluminal pressure sensors and longitudinal contractions by a force transducer. Responses to VS were recorded before and after giving succinylcholine, atropine, or both. Circular contractions characteristic of striated and smooth muscle were recorded from the mid- and distal esophagus, respectively. With increases in VS frequency, the striated muscle showed rapid, repetitive twitches progressing to tetany. These fast contractions had a square-wave configuration at VS greater than or equal to 10 Hz and were abolished by succinylcholine. In contrast, the slow-twitch circular responses of smooth muscle showed no repetitive twitches and had a bell-shaped configuration. Two types of circular smooth-muscle contractions were observed: 1) A wave "on contractions" occurred 0.5-1.0 s after VS onset, regardless of stimulus length, and 2) infrequent B wave "off contractions" occurred only after stimulus cessation. The longitudinal esophageal contractions had a compound wave form with both striated and smooth-muscle components. Atropine abolished the slow component of the longitudinal contraction, the circular A wave, and peristalsis in the distal esophagus. We conclude that cholinergic motor neurons are an important pathway for eliciting peristalsis in feline esophageal smooth muscle.

Animals↗
PubMed1978

Efficient manometric technic for accurate regional measurement of esophageal body motor activity.

We have developed a single station, manometric recording technic that allows quick and accurate measurement of motor activity occurring in all regions of the esophageal body. The manometric instrumentation features a catheter recording assembly with eight recording orifices spaced at uniform 3 cm. intervals. Each recording lumen is infused with water by a minimally compliant hydraulic-capillary system which achieves accurate recording of peristaltic and nonperistaltic motor activity in the esophageal body at an infusion rate of 0.5 ml./min. Because the recording sites of the manometric assembly span a distance of 21 cm., a distance which approximates the length of the esophageal body in humans, a detailed map of motor activity over the entire length of the esophageal body is achieved by securing the manometric assembly at one suitable portion. Because frequent repositioning of the manometric assembly is eliminated, the method described takes only a few minutes for comprehensive assessment of esophageal body motor activity.

Esophagus↗
PubMed1977

A comparison of colonoscopy and roentgenography for detecting polypoid lesions of the colon.

This study compares the effectiveness of the roentgen and colonoscopic examination of the colon for detecting polypoid lesions. We evaluated the findings in 64 patients with suspected or known polypoid lesions who received the same colon cleansing regimen for both examinations, and were studied by examiners of similar expertise. As in other studies, the endoscopist had the advantage of knowing the roentgen findings, and the colonoscopic findings were often taken to indicate whether or not a lesion was present. In about half the patients, however, a second roentgen examination, repeat colonoscopy, or surgical specimen provided additional information for scoring. For example, a filling defect of the same size and location on two roentgen examinations, but not demonstrated at colonoscopy was scored as a false negative colonoscopic finding. The study results indicate that 54% of small polyps less than or equal to 0.9 cm in size were missed on roentgen examination, whereas no proven misses for lesions of this size were shown for colonoscopy. This absence of colonoscopic false-negative findings for small polyps, however, may be partially explained by a relative insensitivity of the roentgen method. For larger lesions greater than or equal to 1.0 cm in size the miss-rate for the two examinations was similar: 15% for roentgen examination and 12% for colonoscopy. We conclude: (1) Colonoscopy is a more sensitive method than roentgen examination for detecting small polyps of the colon, and (2) Performance of the two examinations may be comparable for demonstrating lesions 1.0 cm or larger in size.

Colonic Neoplasms↗
PubMed1977

Spontaneous atrial thrombosis in aged Syrian hamsters. II. Hemostasis.

Coagulation and fibrinolysis were studied in a colony of aged Syrian hamsters with spontaneous atrial thrombosis, and the results are consistent with concomitant consumption coagulopathy. In comparison to age- and sex-matched hamsters from the same colony, those with atrial thrombi had significantly prolonged prothrombin and partial thromboplastin times, reduced levels of factors II, VII, VIII and X activities and plasminogen; and concentrations of fibrinogen-fibrin split products in excess of 80 microgram/ml. Hematocrits of the thrombosed animals were significantly decreased, total plasma proteins were increased, leukocyte counts were within normal limits, and platelet counts were about half those of the controls. Thrombosed hamsters had significantly reduced plasma albumin content, increased alpha1-, beta-, and gamma-globulins, and reduced A/G ratios. Aged sick hamsters demonstrable thrombi also had reduced coagulation and fibrinolytic activities and platelet counts, but their fibrinogen levels were markedly elevated, and fibrinogen-fibrin split products were either absent or present in trace amounts. This suggests an earlier and/or less acute form of the thrombotic process.

Aging↗
PubMed1977

Evaluation of two microhematocrit methods for quantitating plasma fibrinogen.

Blood samples from several animal species, including man, were used to compare 2 heat-precipitation assays (Millar et al and Schalm et al) with a reference assay (Ratnoff-Menzie) for quantitating plasma fibrinogen. Compared with the Ratnoff-Menzie assay, the heat-precipitation methods significantly underestimated plasma fibrinogen content. The reproducibility of the Millar et al assay was significantly better than that of the Schalm et al assay and approached that of the Ratnoff-Menzie method. The Millar et al assay, a practical test not requiring specialized equipment, is recommended for clinical use in animals.

Animals↗
PubMed1977

Endoscopic electrosurgical papillotomy and manometry in biliary tract disease.

Endoscopic papillotomy was performed in 13 patients after cholecystectomy for retained or recurrent common bile duct calculi (11 patients) and a clinical picture suggesting papillary stenosis (two patients). Following endoscopic papillotomy, ten of the 11 patients spontaneously passed common bile duct (CBD) stones verified on repeated endoscopic retrograde cholangiopancreatography (ERCP) study. One patient failed to pass a large CBD calculus; one patient experienced cholangitis three months after in inadequate papillotomy and required operative intervention. Endoscopic papillotomy substantially decreased the pressure gradient existing between the CBD and the duodenum in all five patients studied with ERCP manometry. Endoscopic papillotomy is a relatively safe and effective procedure for postcholecystectomy patients with retained or recurrent CBD stones. The majority of CBD stones will pass spontaneously if the papillotomy is adequate.

Ampulla of Vater↗
PubMed1977

Effect of bethanechol on gastroesophageal reflux.

In this study we determined the acute effect of bethanechol (5 mg SC) on gastroesophageal reflux (GER) and lower esophageal sphincter pressure (LESP) in 27 patients with symptomatic esophagitis. The effect of bethanechol on esophageal acid clearance was also determined in 7 of the patients. Intraluminal pH monitoring prior to bethanechol administration demonstrated free or stress-induced reflux episodes in 18 of the 27 patients. Following bethanechol (1) LESP increased significantly, (2) GER diminished or ceased in many of the patients, and (3) acid clearance times decreased significantly. Some individuals, however, continued to reflux despite LESP elevation to 30 mm Hg or more. This latter finding suggests that LESP alone is not the sole factor governing LES competency. Other factors such as improved esophageal emptying may also contribute to the beneficial therapeutic effect of bethanechol in patients with heartburn.

Bethanechol Compounds↗
PubMed1977

The caudad angle view: a helpful adjunct in excretory urography.

The caudad angle view is a useful ancillary projection for evaluating renal morphology during excretory urography. This view, easily obtained during routine urography, often adds important information about renal anatomy and patholgoy which is not apparent on conventional radiographs.

Humans↗
PubMed1977

Colonic polyp detection: role of roentgenography and colonoscopy.

In order to determine the relative yields of colonoscopic and radiologic examinations of the colon, the following guidelines are suggested: (a) prospective data collection; (b) a standard, effective colon cleansing regimen; (c) colonoscopic and radiologic examiners of comparable expertise; (d) examiners should be unaware of each other's findings; (e) a suitable method for demonstrating false-negative findings and for resolving conflicting findings between the two examinations; and (f) indexing of the study findings as to lesion size, lesion location, quality of colon cleansing, and examiner's level of confidence. The two examinations should be used as complementary diagnostic procedures.

Colon↗
PubMed1977

Esophageal manometry in the opossum.

The opossum esophagus is commonly used as an animal model of the human esophagus. We used esophageal manometry in normal animals to provide basal data about normal esophageal motor functions in vivo in this species. At rest, separate and distinct high pressure zones can be recorded at the level of the lower esophageal sphincter, diaphragmatic hiatus, aortic arch, and upper esophageal sphincter. Each zone demonstrates a characteristic pattern of pressures in the radii of the coronal section and a characteristic response to swallowing. The hiatal and aortic zones can be mistaken for the esophageal sphincters. Pressures in the sphincters fall with swallowing. Peristalsis is not bolus-dependent and occurs with 98% of swallows. Pressures generated by peristalsis are greater in the middle of the esophagus than at the ends. Values for resting lower esophageal sphincter pressure and the characteristics of peristalsis were reproducible between different studies in the same animals.

Animals↗
PubMed1977

An evaluation of colon cleansing regimens.

To study the efficacy of colon cleansing regimens, 500 hospital outpatients were randomly assigned to one of four regimens. Two featured castor oil followed by phosphate enema and two used magnesium citrate and bisacodyl. For the 349 patients who completed all components of the regimens, quality of the subsequent barium enema examination was scored by three radiologists in a blind manner. Regimens featuring magnesium citrate and bisacodyl were found to be significantly superior to those featuring castor oil. Calcium bisdiocytl sulfosuccinate did not improve the quality of colon cleansing but appeared to decrease the incidence of abdominal cramping in patients receiving magnesium citrate and bisacodyl. It is hoped that the investigative approach used in this study may serve as a model for future testing of colon cleansing regimens.

Adolescent↗