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Biomedical subjects

R Spence

Publications and source records attributed to R Spence.

14 recordsLinked to original sources
PubMed2001

Ammonia vapour in the mouth as a diagnostic marker for Helicobacter pylori infection: preliminary 'proof of principle' pharmacological investigations.

Most current non-invasive tests for Helicobacter pylori depend on the conversion of labelled (13C or 14C) urea to labelled carbon dioxide (13CO2 or 14CO2) and ammonium (NH4+) by the enzyme urease, with the labelled CO2 detected in exhaled air. Despite suggestions going back over a number of years, the alternative possibility of using NH4+ (in the form of gaseous ammonia [NH3]) as the test parameter has received little or no attention. However, this approach is now being explored using a chemiresistive sensor detecting sub-parts per million concentrations of NH3. An in vitro 'glass stomach' (containing various volumes of hydrochloric acid [HCl] and ammonium chloride [NH4Cl]) was used to evaluate the means of increasing 'gastric' pH to that of the NH4+-->NH3 transition that occurs significantly at pH 9.24. This 'stomach' also was used to study mechanisms by which NH3 may be expelled in a pulse (as a surrogate belch), either by the in situ production of CO2 or through an exogenous source. On the basis of the protocols developed, H. pylori-negative subjects were tested before and after ingestion of 10 mg NH4Cl (as a surrogate for bacteria-produced NH4,), and H. pylori-positive subjects were tested without taking urea or NH4Cl. 'Intragastric' pH in the in vitro 'glass stomach' could be increased above pH 9.24 by adding a mixture of 15-30 mL magnesium hydroxide mixture (or the proprietary equivalent) and 50 mL water, and the resulting NH3 expelled by adding 100 mL CO2-saturated cold water (sparkling water). In vivo, NH3 levels in the oral cavity of H. pylori-negative subjects were increased after ingestion of 10 mg NH4Cl; however, levels in the oral cavity of a small number of H. pylori-positive subjects were two- to threefold higher after magnesium hydroxide and sparkling water. On the basis of in vitro studies, an in vivo protocol was developed to increase gastric pH above that required for the NH4+-->NH3 transition, and a mechanism established to release the NH3 into the oral cavity. Preliminary in vivo data confirm the chemiresistive sensor is sufficiently sensitive to NH3 to distinguish H. pylori-negative subjects who have taken 10 mg NH4Cl from those who have not, and clearly distinguish H. pylori-negative subjects from H. pylori-positive subjects. Ingestion of urea or other labelled tracers is not required, nor is belching; and the sensor takes less than two minutes to reach a maximum response. The data provide good evidence that the chemiresistive detection of NH3 has considerable potential as a rapid, point-of-care diagnostic test for H. pylori infection.

Ammonia↗
PubMed1994

Elbow defect coverage with a one-staged, tunneled latissimus dorsi transposition flap.

Upper extremity reconstruction is very challenging due to the unavailability of expendable local muscles. A review of the literature reveals that the latissimus dorsi muscle has been used for functional restoration of elbow extension and flexion as well as soft-tissue coverage of upper arm and shoulder defects. In addition, the latissimus dorsi muscle has been used for forearm reconstruction. Although we have been unable to find any reports of the use of the latissimus dorsi muscle for pure coverage of complex elbow wounds, we have successfully used the latissimus dorsi transposition flap to cover complex elbow defects in a one-staged procedure for patients. In 3 of 4 patients, the latissimus dorsi transposition flap was the first choice. In the other patient, the latissimus dorsi flap was successfully used as an alternative choice for coverage of an open, comminuted elbow fracture after a failed rectus abdominis free tissue transfer. A technique is described for coverage of complex elbow defects by transferring a latissimus dorsi muscle on its vascular pedicle with or without an overlying skin island. This procedure is safe, one-staged, and results in minimal donor morbidity. The latissimus dorsi transposition flap provides reliable coverage of complex elbow defects and should be considered the flap of choice for coverage of the elbow.

Adult↗
PubMed1994

Nursing management of venous ulceration.

Chronic diseases rob many individuals of their physical, emotional, and economic resources. Nonhealing venous ulcers are no exception. They provide a challenge to the nurse in the outpatient setting, who must integrate the complex concepts of wound healing with the patient's lifestyle and financial concerns. The purpose of this article is to provide an overview of the disease process, treatment, and nursing management of patients with venous ulcers.

Bandages↗
PubMed1993

Morphometric analysis of colorectal cancer.

Thirteen nuclear and cellular morphometric variables were measured in 312 cases of colorectal adenocarcinoma. All variables, except nuclear shape factors, differed significantly (P < 0.001) between normal colorectal and tumor tissue. In adenocarcinomas, epithelial nuclei in well-differentiated mucosa tended to be elliptic, while those in poorly differentiated mucosa were more spheric. Increasing values of maximum nuclear and elliptic diameter were associated with progression from none to simple tubule configuration (P < 0.001), none to easily discerned nuclear polarity (P < 0.001), and expanding growth pattern (P < 0.001). Univariate survival analysis revealed that none of the morphometric variables was significantly related to patient survival. Multivariate regression analysis showed that no morphometric variable could add significantly to a model containing the variables of patient age, Dukes stage, and tumor differentiation. Morphometry may be useful in distinguishing malignant from normal tissue and degrees of differentiation, but it is of little prognostic value in colorectal adenocarcinoma.

Adenocarcinoma↗
PubMed1984

Locus of control in children of divorce.

Scores on the Nowicki-Strickland Locus of Control Scale for Children (N-SLOCSC) were compared for third and fifth grade boys and girls from intact versus maritally disrupted family backgrounds. Significant main effects for each independent variable revealed that fifth graders more than third, boys more than girls, and the marital disruption more than the intact group, exhibited higher internality in their locus of control scores. These findings strongly suggest that experiencing a parental divorce in childhood has a significant influence on generalized perceptions of personal control and effectance, perceptions which may ultimately mediate both short- and long-term outcomes in children's post-divorce adjustment.

Age Factors↗
PubMed1981

The prevalence of disturbance of cardiac rhythm in randomly selected New Zealand adults.

Continuous portable 24 hour tape recorded monitoring of the electrocardiogram in 400 randomly selected adults was used to provide data about arrhythmia during normal daily activity. The sample contained 203 females and 197 males of which 100 were Maori and 300 European. The ages ranged from 20 to 70 years and the mean was 45.1. The only exclusion was inability to wear a Holter monitor. Arrhythmia, mainly asymptomatic, occurred in 318 (80 percent). There was equal prevalence in Maori and European. In 43 (13.5 percent) it was ventricular, in 122 (38.4 percent) it was supraventricular, and in a further 153 (48.1 percent) it was combined. In 45 (14.1 percent) ventricular ectopy was considered potentially serious. Physical abnormality of some description, excluding arrhythmia, was present in 90 percent of Maoris and 62 percent of Europeans. Arrhythmia was slightly less prevalent in totally normal subjects than in those considered to have some abnormality (p = less than 0.05).

Activities of Daily Living↗
PubMed1981

Transluminal angioplasty of the iliac and femoral arteries: follow-up results without anticoagulation.

With the advent of the angiographic balloon catheter, transluminal angioplasty has become a more effective procedure for the alleviation of symptoms of peripheral ischemia. In the past two and a half years we have performed this procedure on over 208 iliac and femoral arteries. One hundred twenty iliac arteries were dilated. Of these, 86% remained patent at one year and 83% at two years. Eighty-eight femoral arteries were dilated. Of these, 75% remained patent at one year and 67% at two years. These vessel survival rates are slightly less than those following surgery. However, the morbidity from transluminal angioplasty is very low and the mortality is essentially zero.

Adult↗