Search PubMed⌕ Search

Biomedical subjects

K Alexander

Publications and source records attributed to K Alexander.

At least 145 records · Page 8Linked to original sources
PubMed1987

Temperature-dependent laser Doppler fluxmetry in healthy and patients with peripheral arterial occlusive disease.

Laser Doppler flux (LDF) was determined at the forefoot in 17 healthy volunteers and 16 patients with mild peripheral arterial occlusive disease. LDF was assessed simultaneously by two probes, one was unheated and the other was run with a probe holder temperature of 37 degrees C. During occlusion of the venous circulation a decrease between 43 and 61% was recorded in both groups and at both temperatures. When the leg was elevated there was an increase of about 60% in unheated skin; at 37 degrees C LDF was impaired significantly in patients. During leg dependency LDF decreased in 15 of the volunteers by 44 and 50% which is the result of the physiological vasoconstrictor response. In patients there was a decrease in unheated skin in 12 cases, in heated skin only in 8 cases. When pure oxygen was inhaled, LDF was unchanged in probands, but increased in patients when measured at 37 degrees C. Reactive hyperaemia flow was about three times higher in unheated skin than in heated skin. Reproducibility was best during leg elevation and was more reliable for measurements at 37 degrees C. Rhythmical variations had a frequency of about 4 cycles/min in healthy subjects and 2.6 cycles/min in patients. As a rule, in both groups frequencies at 37 degrees C were higher as compared with unheated skin. Patients had lower frequencies than probands at both temperatures. During intraarterial application of two differently acting drugs quite different reactions of LDF could be recorded. Measurements of LDF at 37 degrees C made differences between patients with PAOD and healthy volunteers more obvious. Moreover, vasomotional changes in skin blood flow could better be studied at this temperature.

Adult↗
PubMed1987

Transcutaneous oxygen pressure measured at two different electrode core temperatures in healthy volunteers and patients with arterial occlusive disease.

The influence of two different electrode core temperatures on transcutaneous oxygen pressure (tcPO2) was studied in ten probands and 28 patients with peripheral arterial occlusive disease. Hyperaemisation of skin by an electrode core temperature of 44 degrees C reflects local hyperaemia flow and can be reproduced constantly. At 37 degrees C low tcPO2 values are recorded which are in good accordance with mathematically calculated capillary dome PO2. According to great physiological alterations in skin perfusion tcPO2 (37 degrees C) varies in wide ranges. This mode of measurement is well suited to study physiological autoregulation mechanisms or the influence of drugs on skin perfusion. The herein reported results are: forefoot tcPO2 (37 degrees C, 44 degrees C) in volunteers is significantly higher than in patients; forefoot tcPO2 (37 degrees C, 44 degrees C) of patients with diabetes mellitus is significantly higher than in nondiabetics; prestenotic tcPO2 (37 degrees C, 44 degrees C) is about two times higher than poststenotic tcPO2 (37 degrees C, 44 degrees C); tcPO2 (37 degrees C) in probands decreased significantly during occlusion of the venous circulation; tcPO2 (44 degrees C) increased in probands and patients when standing up; however, tcPO2 (37 degrees C) decreased in healthy persons and increased in patients when standing up; after a 5-min suprasystolic cuff occlusion of the arterial circulation there was a four- to six-fold increase of tcPO2 (37 degrees C) which indicates reactive skin capillary flow. In conclusion tcPO2 (37 degrees C) permits measurement of relative changes of skin capillary flow under physiological conditions so that autoregulating mechanisms can be studied.

Adult↗
PubMed1986

Effects of intra-arterial prostaglandin E1 in patients with peripheral arterial occlusive disease.

The effects of intraarterially administered prostaglandin E1 (PGE1) on macrocirculatory, microcirculatory and metabolic parameters in patients with peripheral arterial occlusive disease were studied. Nutritive calf muscle blood flow, as determined with the xenon-clearance technique, and muscle tissue oxygen pressure increased markedly in patients with obliterations of the femoral artery. Transcutaneous PO2 as indicator for cutaneous blood flow increased in prestenotic regions dose-dependently whereas there was a clear poststenotic decrease during the infusion period. High lactate/pyruvate ratios in the femoral vein were significantly decreased by PGE1 treatment. PO2 in the femoral vein increased significantly. Thus, PGE1 has some beneficial effects on muscle circulation in these patients.

Adult↗
PubMed1986

[Radiologic diagnosis of thoracic outlet syndrome and its vascular complications].

The term "Thoracic Outlet Syndrome" (TOS) applies to all neurological and vascular symptoms caused by compression of the nerves and vessels situated in the outlet (inlet) of the thorax and the costoclavicular area. The clinical and radiological results of 20 patients with acquired and congenital TOS are presented and the relevant literature is reviewed. The different radiological findings of plain chest X-ray, phlebography, intravenous DSA and arteriography are demonstrated with special emphasis on the vascular complications of TOS.

Adolescent↗
PubMed1985

[Ergotism].

Explore the source record for details and available documents.

Ergot Alkaloids↗
PubMed1985

Near-UV radiation from the operating microscope and pseudophakic cystoid macular edema.

We performed a prospective randomized study of 297 patients to determine the effect of a UV-blocking filter on the operating microscope on the angiographic incidence of cystoid macular edema in patients undergoing extracapsular surgery with implantation of a posterior chamber lens. Patients were randomly allocated preoperatively to two groups undergoing surgery with or without a UV filter in place. Of the 297 patients, 205 had angiograms readable for the presence or absence of cystoid macular edema. The incidence of aphakic cystoid macular edema in patients without the filter was 21% v 17.3% in the group with a filter. This difference was not significant. The presence of a UV-blocking filter on the operating microscope makes no difference in the angiographic incidence of cystoid macular edema or the visual outcome in these cases.

Cataract Extraction↗
PubMed1985

Muscle tissue oxygen pressure in patients with arterial occlusive disease.

Oxygen pressure histograms were determined with the multiwire surface electrode from the gastrocnemius muscle in patients with arterial occlusive disease and compared with those of healthy volunteers. Seven out of 22 patients had normally distributed histograms like volunteers, but the mean PO2 values were lower than the total mean value of the volunteers. Fifteen patients showed scattered histograms with dominating low PO2 values. Ten out of 11 patients suffering from diabetes mellitus had scattered histograms. When perfusion pressure was impaired by elevating the leg or the musculature was stressed in 7 patients the histograms' form of all these patients changed significantly. Median PO2 fell in all cases with clinically decompensated occlusive disease. Percutaneous transluminal angioplasty of an occlusion of the superficial femoral artery led to a significant shift of the histogram to higher PO2 values. The scattered histograms of patients suffering from arterial occlusive disease are thought to be caused by an inhomogeneous blood flow probably induced by the closure of arterioles.

Angioplasty, Balloon↗