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Biomedical subjects

P A Barnes

Publications and source records attributed to P A Barnes.

At least 19 recordsLinked to original sources
PubMed2006

Activated carbon from vetiver roots: gas and liquid adsorption studies.

Large quantities of lignocellulosic residues result from the industrial production of essential oil from vetiver grass (Vetiveria zizanioides) roots. These residues could be used for the production of activated carbon. The yield of char obtained after vetiver roots pyrolysis follows an equation recently developed [A. Ouensanga, L. Largitte, M.A. Arsene, The dependence of char yield on the amounts of components in precursors for pyrolysed tropical fruit stones and seeds, Micropor. Mesopor. Mater. 59 (2003) 85-91]. The N(2) adsorption isotherm follows either the Freundlich law K(F)P(alpha) which is the small alpha equation limit of a Weibull shaped isotherm or the classical BET isotherm. The surface area of the activated carbons are determined using the BET method. The K(F) value is proportional to the BET surface area. The alpha value increases slightly when the burn-off increases and also when there is a clear increase in the micropore distribution width.

Adsorption↗
PubMed1994

Esthesioneuroblastoma presenting as an orbital mass in a young child.

A 3-year-old boy presented with uniocular proptosis and ophthalmoplegia. Investigation revealed a mass involving the right orbit with extension into the left orbit and paranasal sinuses, and intracranial extension involving both frontal lobes. Biopsy of an enlarged cervical node and the intranasal mass revealed esthesioneuroblastoma. This tumor has been reported rarely in a child this age, and only 12 case reports document patients under 10 years of age. The presentation as an orbital mass is previously unreported and must now be considered in the differential diagnosis of proptosis in childhood. The usual clinical, radiological, and pathological features of olfactory esthesioneuroblastoma are reviewed.

Child, Preschool↗
PubMed1985

Large volume crystalloid resuscitation does not increase extravascular lung water.

The purpose of this study was to determine whether Ringer's lactate solution increases extravascular lung water (EVLW) during resuscitation after hemorrhagic shock. Ten sheep anesthetized with thiamylal were bled to a mean arterial pressure (MAP) of 50 mm Hg; further bleeding maintained that pressure for 30 min. Resuscitation fluid consisted of Ringer's lactate solution in volumes necessary to restore and maintain for 1 hr MAP, pulmonary capillary wedge pressure (PCWP), and cardiac index at levels equal to those measured before bleeding. After volume replacement, the colloid oncotic pressure (COP) - PCWP gradient (COP - PCWP) decreased from 12 +/- 3 to 2 +/- 5 mm Hg (P less than 0.001). After volume restoration, COP decreased from 19 +/- 8 mm Hg to 12 +/- 2 mm Hg (P less than 0.001). Despite the large volume of fluid administered, EVLW did not increase. Crystalloid resuscitation does not necessarily increase EVLW despite significant decreases in COP and COP - PCWP gradient.

Animals↗
PubMed1984

The accuracy of age-sex registers in general practice.

A ;point-prevalent evaluation' of the accuracy of the age-sex register (ASR) was undertaken in 10 general practices. The average ASR inflation rate was 4 per cent when compared with the Family Practitioner Committee (FPC) register (range 2.2-8.3 per cent) and 7.2 per cent when compared with the patients themselves (range 2.6-19.4 per cent). List deflation was no more than 2 per cent overall. There was a wide interpractice variation in the accuracy of the ASR, and two of the factors that may be associated with this are the situation in an inner city renewal area and a large proportion of patients in the 20-40 years age group. When the patients were asked to verify the information contained on the ASR it was found that the address was incorrect for 10 per cent of patients (range 5.0-20.0 per cent) and the date of birth was incorrect for 5 per cent.Before using it for research purposes, the ASR should be checked against the FPC register, and in view of our findings it should also be checked with a sample of the patients themselves to ensure a sufficiently accurate population denominator.

England↗
PubMed1983

The fatty liver: pitfalls of the CT and angiographic evaluation of metastatic disease.

Five patients with known primary malignancy demonstrated fatty infiltration of the liver on routine computed tomography (CT) examination. Within the diffuse fatty infiltration were focal areas of relatively increased beam attenuation in four cases. These areas of increased beam attenuation are nonspecific as to etiology. Their differential diagnosis is discussed. Since the true extent of the neoplastic process may be underestimated by conventional CT and celiac angiography, superselective angiography, computed angiotomography, or biopsy is required to accurately assess the etiology and the extent of the disease.

Adult↗
PubMed1982

Imaging the pancreatic neoplasm.

The radiologic approach to the pancreatic mass is discussed. The efficacy of the various diagnostic methods is also discussed. Cross-sectional imaging techniques have greatly improved the accuracy of diagnosis of pancreatic lesions and are less invasive than either angiography or ERCP. Computed tomography is more reliable than sonography and should be the initial diagnostic procedure in any patient who is suspected of having a pancreatic neoplasm.

Angiography↗
PubMed1982

Computed tomography and routine chest radiography in oat cell carcinoma of the lung.

Computed tomography (CT) scans of the chest and routine postero-anterior and lateral chest films were compared in 32 patients with pathologically proven oat cell carcinoma of the lung. Nineteen of the 32 patients were examined prior to any form of therapy. Overall, CT gave more information about the extent of disease. The significance of this information may be of little value because the routine chest films also demonstrated mediastinal involvement, although to a lesser degree. Computed tomography of the chest should not be the initial diagnostic staging procedure in oat cell carcinoma, but used selectively. It can be quite useful in patients who have a partially opacified lung, possibly for the evaluation of mediastinum after therapy, and for the evaluation of possible abdominal metastases.

Adult↗
PubMed1982

Post-therapy CT-detected mass in lymphoma patients: is it viable tissue?

The demonstration by computed tomography (CT) of enlarged nodes and/or masses in lymphoma patients has been interpreted as indicating that active disease is present. Four cases are presented in which either biopsy or laparotomy of a CT-detected mass after therapy revealed fibrous tissue with no evidence of viable neoplasm. These four cases demonstrate the possible pitfall of diagnosing viable lymphoma in masses detected by CT after therapy.

Adult↗
PubMed1982

CT detection of hepatic metastases with Ethiodized Oil Emulsion 13.

The use of an experimental liposoluble contrast agent-Ethiodized Oil Emulsion 13 (EOE 13)--is described in hepatic computed tomography (CT) of 23 oncologic patients. Without exception, all the hepatic metastases were better delineated in the EOE 13 enhanced scans. The postcontrast scans also detected an increased number of lesions but not all were malignant. There is no specificity to the increased lesion detection. Various splenic abnormalities were detected. Very few minor side effects and no major side effects were caused by the contrast media. We feel that with time, hepatic specific agents such as EOE 13 will become the contrast media of choice in hepatic CT examinations. Also, CT with hepatic specific agents may become the preoperative examination of choice in candidates for partial hepatectomy.

Adult↗
PubMed1982

EOE-13 in the detection of hepatosplenic lymphoma.

Thirty-nine patients with lymphoma were evaluated prospectively to determine the usefulness of Ethiodol-Oil-Emulsion-13 (EOE-13) in the detection of hepatosplenic lymphoma by computed tomography. The detection rate in the spleen increased from 8% (before EOE-13 infusion) to 92% (after EOE-13 infusion). In ten of 39 patients (25%) in this series, lymphomatous disease was recognized only on the postinfusion computed tomographic scan. The postinfusion EOE-13 study demonstrated additional visceral abnormalities in 38% of the patients. The potential usefulness, limitations, and toxicity of this hepatosplenic-specific imaging agent are discussed.

Ethiodized Oil↗
PubMed1982

Limited CT studies in monitoring treatment of lymphoma.

One hundred and two follow-up CT studies in 50 patients with a diagnosis of lymphoma were reviewed to determine the efficacy of limited CT studies for determining therapy. The overall correlation between the limited CT study and the complete CT study was 98%. No mixed responses occurred in 102 cases. Two patients, both with diffuse histocytic lymphoma treated by chemotherapy, showed progression of disease outside a stable tumor bed not detected by a limited CT study. The economic implications, technique, and limitations of limited CT studies are presented.

Follow-Up Studies↗
PubMed1981

Pitfalls in the diagnosis of hepatic cysts by computed tomography.

Seven patients with computed tomographic (CT) evidence of cystic hepatic lesions are presented. In these cases, CT could not reliably distinguish benign hepatic cysts from other intrahepatic and extrahepatic cystic lesions. The attenuation coefficients of simple cysts and inflammatory or neoplastic lesions were similar, and smooth margins occurred in all three of these conditions. It was not possible to visualize and differentiate lesion walls from the surrounding normal hepatic parenchyma in some cases. It is concluded that the specificity of CT in the differentiation of benign cysts and other lesions is lower in the liver than it is in other areas, such as the kidney, and that in cases of diagnostic uncertainty, biopsy should be performed.

Adult↗