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Biomedical subjects

G Beer

Publications and source records attributed to G Beer.

51 records · Page 3Linked to original sources
PubMed1975

Determination of plasma volume by 113min-labeled transferrin.

The binding property of ionic indium (In3+) with plasma transferrin was utilized for determination of plasma volumes (PV) of whole body and individual organs in small animals. Plasma transferrin from a donor rat was labeled with 15-17 muCi 113mIn/ml plasma and injected into the tested rats. PV were determined either by extrapolation to the dilution at time zero (for whole animals) or by calculation of the ratio, organ radiation: radiation of a plasma unit volume (for organs). The reliability of the method for determination of whole-body PV was ascertained by comparing the results obtained with those obtained simultaneously by the Evans blue dilution method. Whole body PV values obtained by the two methods were similar, with a correlation coefficient (r) of 0.997. The short half life of 113mIn enables it to be used with other nuclides which have similar or different energies in the same sample; indium radiation was counted first and after it had disappeared the activity of the other nuclide could be measured.

Animals↗
PubMed1975

Autoregulatory responses of cerebral blood vessels in hypercapnia.

Simultaneous determinations of cerebral blood flow, measured by 85Kr clearance, and of intracranial pressure, measured in the cisterna magna, were made in anesthetized normocapnic and hypercapnic vagotomized cats. All animals were tested at their normal arterial pressure and at elevated arterial pressure induced by angiotensin infusion. Autoregulatory responses of cerebral blood vessels to the elevation of blood pressure were quantitatively characterized by a pressure-flow function. In 10 of 12 animals, hypercapnia interfered with the autoregulatory responses of the cerebral vasculature. Analysis of the simultaneous behavior of intracranial pressure and cerebral vascular resistance did not indicate that changes in intracranial pressure affected the autoregulatory responses. The results of this study support the view that CO2 interferes with the basic reaction of vascular smooth muscle to contract after distension by increased transmural pressure.

Air↗
PubMed1970

[Contact lenses].

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Contact Lenses↗
PubMedDate not supplied

Non-invasive assessment of carotid arteries: a comparison of techniques used in two laboratories.

Fifty-one patients were examined non-invasively in two different laboratories and underwent angiography for carotid artery disease. Results of the two examinations and angiography were compared. In one laboratory continuous wave Doppler ultrasonography of the accessible extracranial arteries was used; in the other laboratory spectral analysis of the Doppler signals and angioscan imaging of the bifurcation was carried out. Accuracy of the two examinations (when compared with angiography) were similar for stenoses of more than 50%; spectral analysis and angioscan were better than continuous wave Doppler in detection of less than 50% stenoses.

Arterial Occlusive Diseases↗
PubMedDate not supplied

Non invasive testing in carotid artery occlusive disease: the value of direct Doppler ultrasonography.

Non invasive examination of carotid artery occlusive disease, as performed in our vascular laboratory, was compared to angiographic and operative findings in 65 patients (74 arteries). The sensitivity of carotid phonoangiography alone in detecting carotid artery stenosis was 73%. Ophthalmic flow direction was reversed in only 32% of stenosed arteries. Resistance index of directional Doppler sonography was high in only 15% of stenosed arteries. The most reliable part of the whole examination proved to be the direct "auscultation" of the carotid vessels in the neck. The overall sensitivity and specificity of this test was 88% and 64%, respectively; sensitivity being 94% for stenoses of over 50% in diameter and 55% for stenoses less than 50% in diameter. The major drawback of the test was its subjectiveness.

Adult↗
PubMedDate not supplied

Percutaneous chemical lumbar sympathectomy with alcohol with computed tomography control.

Percutaneous chemical lumbar sympathectomy with alcohol (PCLSA) using computed tomography (CT) control was performed in 8 patients suffering from advanced peripheral arterial occlusive disease. PCLSA under CT guidance was found to be a simple and safe procedure. The use of CT control added precision in the guidance of needle placement. Positive results were obtained in all patients, without significant morbidity. PCLSA may be an alternative to surgical sympathectomy.

Adult↗
PubMedDate not supplied

On the correlation of acoustical sounds and ultrasound velocimetry in the subclavian steal syndrome.

Patients with suspected subclavian steal syndrome were examined by Doppler ultrasonography and by auscultation, particular attention being paid to the velocity profiles and "augmentation bruits" in the vertebral arteries, and the findings being compared with angiography. This was done with the patients at rest and during and after ischemic exercise of the affected arm. The recorded bruits were analyzed for their frequency content and it was found that the bruits in a particular kind of vessel are well characterized by the first moment of the spectrum. A good correlation between the Doppler ultrasound results and the acoustical sound pattern accompanying hyperemic flow was found. The two methods are supplementary and complementary in the non-invasive diagnosis of subclavian steal syndrome. To demonstrate the multifacetted appearances of the syndrome three cases are discussed.

Aged↗
PubMedDate not supplied

Early experience with balloon catheter angioplasty.

Percutaneous transluminal angioplasty with the Gruntzig balloon catheter was undertaken in 12 patients with chronic lower limb ischemia. As judged by postdilatation angiography, the procedure was successful in 11 patients (91.6%). Nine patients were either free of symptoms or very significantly improved at follow-up, one to five months after angioplasty. Indications for angioplasty and the technique are described and discussed.

Adult↗