PubMed Health⌕ Search

Biomedical subjects

J Jamieson

Publications and source records attributed to J Jamieson.

8 recordsLinked to original sources
PubMed1992

Effect of Nissen fundoplication on esophageal motor function.

The effect of Nissen fundoplication on the compromised esophageal body function in patients with gastroesophageal reflux disease is poorly understood. Stationary manometry of the distal esophageal body was performed in 50 normal volunteers and compared with that in 40 patients with increased esophageal acid exposure. The studies were performed before and 11 to 68 months (median, 30 months) after successful reflux control and healing of acute mucosal injury with Nissen fundoplication. Before the operation, patients had a lower mean amplitude of contractions, higher prevalence of low amplitude, and interrupted and simultaneous contractions in the distal esophagus compared with normal volunteers. Nissen fundoplication restored the lower esophageal sphincter to normal, increased contraction amplitude, and reduced the prevalence of low-amplitude contractions but did not improve contraction amplitude in patients with a mean amplitude below 35 mm Hg. Fundoplication improves esophageal contraction amplitude but should be performed before the mean contraction amplitude falls below 35 mm Hg.

Circadian Rhythm↗
PubMed1992

The law of initial values: a four factor theory.

The effects of four factors, measurement error, skewness, floor/ceiling effects, and reactivity, on the correlation between change and initial level were studied using computer simulations. A total of 24 conditions were simulated: the four factors being examined together with variations in the direction of change, level of measurement error and/or strength of effect. In each condition ten random samples of 50 cases were generated by SPSSX, and compute functions were used to model the effects of interest. Three factors were capable of producing a negative correlation (the Law of Initial Values, LIV): measurement error, skewness, and floor/ceiling effects. Two factors yielded a positive correlation (anti-LIV effect): reactivity and skewness. The issue of how to determine which factor is operating in a given situation is discussed.

Biology↗
PubMed1991

Three-dimensional imaging of the lower esophageal sphincter in gastroesophageal reflux disease.

The resistance of the lower esophageal sphincter to reflux of gastric juice is determined by the integrated effects of radial pressures exerted over the entire length of the sphincter. This can be quantitated by three-dimensional computerized imaging of sphincter pressures obtained by a pullback of radially oriented pressure transducers and by calculating the volume of this image, in other words, the sphincter pressure vector volume. Validation studies showed that sphincter imaging based on a stepwise pullback of a catheter with four or eight radial side holes is superior to a rapid motorized pullback. Compared with 50 healthy volunteers, the total and abdominal sphincter pressure vector volume was lower in 150 patients with increased esophageal acid exposure (p less than 0.001) and decreased with increasing esophageal mucosal damage (p less than 0.01). Calculation of the sphincter pressure vector volume was superior to standard techniques in identifying a mechanically defective sphincter as the cause of increased esophageal acid exposure, particularly in patients without mucosal damage. The Nissen and Belsey fundoplication increased the total and intra-abdominal sphincter pressure vector volume (p less than 0.001) and normalized the three-dimensional sphincter image. Failure to do so was associated with recurrent or persistent reflux. These data indicate that three-dimensional imaging of the lower esophageal sphincter improves the identification of patients who would benefit from an antireflux procedure. Analysis of the three-dimensional sphincter pressure profile should become the standard for evaluation of the lower esophageal sphincter.

Adult↗
PubMed1990

Perceptions of athletic injuries by athletes, coaches, and medical professionals.

35 athletes, their coaches, and medical professionals independently assessed the disruption, seriousness, and short-term effects of the athletes' athletic injuries. Athletes underestimated the disruption and short-term effects of the injury when compared to medical professionals. 25 lower level athletes and those with no previous serious athletic injury overestimated the short-term effects of their injuries. Coaches overestimated the disrupting effects of the injury for 10 higher level athletes and 25 athletes with no previous injury.

Activities of Daily Living↗
PubMed1989

Analysis of thirty-two patients with Schatzki's ring.

Schatzki's ring is a distinct anatomical entity associated with hiatal hernia; however, its significance is unclear. Thirty-two patients with a radiologically demonstrated Schatzki's ring were compared with 32 patients with hiatal hernia and no Schatzki's ring. Schatzki's ring was confirmed on endoscopy in 59 percent of patients. Seventy-five percent of patients with Schatzki's ring presented with dysphagia compared with 41 percent of control patients (p less than 0.01). Heartburn and regurgitation were less frequent than in control subjects (38 percent versus 91 percent, p less than 0.0001). Schatzki's ring patients were found to have a lower incidence of proven gastroesophageal reflux on 24-hour pH monitoring. Those with proven reflux were found to have a more efficient lower esophageal sphincter than control patients. Sixty-two percent of Schatzki's ring patients without proven reflux had a history of chronic ingestion of drugs known to be damaging to the esophageal mucosa, whereas only 26 percent of patients with reflux had this history. This was found in 16 percent of controls. Sixty-two percent of Schatzki's ring patients without reflux responded to a single dilatation compared with 37 percent of those with reflux. These findings suggest an etiologic relationship between pill lodgement and Schatzki's ring in patients without reflux and indicate that different therapy should be employed in these patients.

Adult↗
PubMed1979

The prediction of swimming performance from behavioral information: a further note.

A recommendation has been made that performance predictions may have to be restricted to matched groups of athletes competing in similar competitive environments. This study assessed that statement for the sport of swimming. A 13 item discriminant function derived from the 1976 Canadian Team was applied to the 1978 Canadian Teams to predict those who would and would not improve over their entry times in the Commonwealth Games competitions. The predictions were no better than chance. The possibility of predicitng swimming performances from data obtained on a similar team does not appear to be feasible.

Behavior↗
PubMed1975

Extent of leg vein thrombosis determined by impedance and 125-I fibrinogen.

Modification of impedance plethysmography to include a thigh cuff improves sensitivity. Twenty-seven of thirty-two subjects (85 per cent) were correctly classified by comparison with phlebograms. Combined surveillance of patients at risk with cuff impedance plethysmography and 125I fibrinogen, carried out fifty subjects after total hip replacement demonstrated that silent venous thrombosis can be detected. Moreover, an estimate of thrombus size can be made, at least to the extent that clinically significant thrombi can be distinguished from minute thrombi.

Evaluation Studies as Topic↗