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C Hare

Publications and source records attributed to C Hare.

10 recordsLinked to original sources
PubMed2002

A comparison of techniques to optimize measurement of voltage changes in electrical impedance tomography by minimizing phase shift errors.

In electrical impedance tomography, errors due to stray capacitance may be reduced by optimization of the reference phase of the demodulator. Two possible methods, maximization of the demodulator output and minimization of reciprocity error have been assessed, applied to each electrode combination individually, or to all combinations as a whole. Using an EIT system with a single impedance measuring circuit and multiplexer to address the 16 electrodes, the methods were tested on resistor-capacitor networks, saline-filled tanks and humans during variation of the saline concentration of a constant fluid volume in the stomach. Optimization of each channel individually gave less error, particularly on humans, and maximization of the output of the demodulator was more robust. This method is, therefore, recommended to optimize systems and reduce systematic errors with similar EIT systems.

Artifacts↗
PubMed2001

Dose reduction in evacuation proctography.

The goal of this study was to reduce the patient radiation dose from evacuation proctography. Ninety-eight consecutive adult patients referred for proctography to investigate difficult rectal evacuation were studied using a digital imaging system with either a standard digital program for barium examinations, a reduced dose digital program (both with and without additional copper filtration), or Video fluoroscopy. Dose-area products were recorded for each examination and the groups were compared. All four protocols produced technically acceptable examinations. The low-dose program with copper filtration (median dose 382 cGy cm2) and Video fluoroscopy (median dose 705 cGy cm2) were associated with significantly less dose than other groups (p < 0.0001). Patient dose during evacuation proctography can be reduced significantly without compromising the diagnostic quality of the examination. A digital program with added copper filtration conveyed the lowest dose.

Adult↗
PubMed1990

A semi-automated method for 5'-ectonucleotidase measurement in lymphocytes.

We describe a simple, non-radioactive, semi-automated method for measuring lymphocyte ecto-5'-nucleotidase activity in isolated cell homogenates. The method which uses inosine 5'-monophosphate (IMP) as a substrate was optimized and requires a total of 4 x 10(6) lymphocytes. The reference range obtained (38.7-180.0 nmol/h per mg protein; means = 106.6) agrees with other isotopic methods which use 14C-IMP. The simplicity, sensitivity (lower limit 10, upper limit 400 nmol/h per mL) and precision (at 114 nmol/h per mL, interday 4.2% s.d., n = 20; intraday 5.8%, n = 10) makes this method suitable for routine clinical laboratory use.

5'-Nucleotidase↗
PubMed1990

Lymphocyte ectoenzyme activity compared in healthy persons and patients seropositive to or at high risk of HIV infection.

We measured two ectoenzymes, ecto-5'-nucleotidase (NT) and dipeptidyl peptidase IV (DP) in the peripheral blood lymphocytes of various groups of HIV-infected patients because of the previous implied relationship of these enzymes to immune function. NT expressed as mean nmol/h per mg protein (+/- s.d.) was significantly depressed in the HIV-seropositive asymptomatic (42 +/- 32; P less than 0.01) and AIDS groups (14 +/- 7; P less than 0.002) when compared with a healthy HIV-seronegative male population (83 +/- 27). The NT activities in asymptomatic HIV-seropositive and HIV-seronegative high risk groups (53 +/- 30) were not significantly different from one another but both groups had significantly higher enzyme activities than the AIDS group (P = 0.01 and less than 0.002, respectively). The seronegative high risk and normal healthy group had similar NT activities. DP activities expressed as mean nmol/h per mg protein (+/- s.d.) in both seropositive asymptomatic (0.188 +/- 0.038) and high risk seronegative (0.180 +/- 0.05) groups had higher enzyme activities than the healthy seronegative (0.117 +/- 0.015; P = 0.02 and 0.05, respectively) and AIDS group (0.096 +/- 0.036; P = 0.002 and 0.02, respectively). The healthy seronegative group had DP activities not significantly different to the AIDS groups. Similarly the high risk seronegative and healthy seropositive group had similar DP activities. These results taken together indicate that measurement of both DP and NT should be evaluated prospectively as a monitor of the clinical progression of HIV infection.

5'-Nucleotidase↗
PubMed1987

Nonpenetrating traumatic rupture of the tricuspid valve. Formation of ventricular septal aneurysm and subsequent septal necrosis: recognition by two-dimensional Doppler echocardiography.

A 26-year old man was admitted with blunt trauma to the chest following a high-speed deceleration injury. A two-dimensional Doppler echocardiogram demonstrated traumatic rupture of the tricuspid valve and a hematoma in the basilar portion of the interventricular septum. Serial two-dimensional Doppler echocardiographic analyses demonstrated evolutionary formation of a septal aneurysm and subsequent rupture with formation of a ventricular septal defect. The usefulness of the two-dimensional Doppler echocardiogram as a screening tool for cardiac contusion is discussed.

Adult↗
PubMed1980

Characterization of myocardial infarcts in the rat.

In 42 male Sprague-Dawley rats, the distribution of coronary arteries, the geometry of myocardial infarcts (MIs) and the involvement of the left ventricular papillary and trabecular muscles, after left coronary occlusion, were investigated. The septal branch was found to be responsible for the blood supply to the septum and, thus, occlusion of the left coronary artery, which spares the septal branch, results in an infarct that does not include the interventricular wall. Myocardial infarct size was measured by planimetry of histologic sections of serial slices of the left ventricle. There was no difference between the average percent of subepicardial (43% +/- 1%) and subendocardial (44% +/- 3%) infarction when the whole left ventricle was considered. Analysis of individual slices had shown that the infarcts comprised a greater percentage of left ventricular circumference at the apex than at the base in both layers of the myocardium. Toward the apex, more subendocardium was infarcted than subepicardium. The papillary and trabecular muscles are minimally involved in 75% of infarcts.

Animals↗
PubMedDate not supplied

Cisapride or metoclopramide to accelerate small bowel transit during barium follow-through examination?

BACKGROUND: Metoclopramide is commonly used to accelerate small bowel transit during barium follow-through (BaFT) examinations, but its action is unpredictable. Cisapride, commonly used to treat gastroesophageal reflux disease, also accelerates small bowel transit and may be a viable alternative. The two were compared in a prospective, randomized, blind study. METHODS: Patients attending for BaFT were randomized to receive either 10 mg cisapride or 20 mg metoclopramide orally 1 h before the barium suspension. BaFT was performed by using a standard technique, and small bowel transit and study quality were compared. Patients also noted any side effects experienced. RESULTS: Of 45 patients recruited, 27 received cisapride and 18 metoclopramide. Median transit time for the cisapride group was 30 min (range = 10-130 min) versus 67.5 min (range = 30-290 min) for the metoclopramide group (p = 0.019). Study quality was comparable. However, nine patients (33%) receiving cisapride experienced nausea versus only one subject (6%) receiving metoclopramide (p = 0.034). CONCLUSIONS: This study suggests that cisapride is a more effective prokinetic agent than metoclopramide, but this benefit is offset by a higher incidence of side effects.

Abdominal Pain↗