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Biomedical subjects

D L Clement

Publications and source records attributed to D L Clement.

At least 181 records · Page 10Linked to original sources
PubMed1980

Reactive hyperemia in patients with intermittent claudication, and correlation with other diagnostic methods.

The value of blood flow measurements was evaluated in 16 patients with intermittent claudication and in 17 healthy sex and age-matched volunteers. Limb volume was recorded with an ECG-triggered venous occlusion plethysmograph (Periflow, Janssen), and the flow values were automatically plotted on a second channel. Resting blood flow was similar in both groups, but all the parameters from the reactive hyperemia curve in the claudication group were significantly different from those in the control group. The present data are preliminary in this respect. In most patients visual inspection of the curve allows differentiation of normal and abnormal. Variability of the flow parameters is found to be small; the time-to-peak flow varies the most, but gives at the same time the largest different results in both groups. Finally, there is a positive correlation between resting blood flow, peak blood flow, and walking distance. The present results suggest that flow measurements provide valuable and objective information about the degree of functional distress caused by obliterative vascular diseases in the limbs.

Aged↗
PubMed1980

Diagnostic performance of segmental plethysmography and Doppler ultrasound in obliterating vascular diseases in the lower limbs.

The diagnostic value of three noninvasive techniques was evaluated in a group of 100 "normal" and 100 "abnormal" limbs. The choice of segmental plethysmography, systolic pressure determination, and Doppler velocity curve was based on the fact that these methods are noninvasive, inexpensive, and atraumatic; they can easily be performed by paramedical personnel. There was a statistically significant difference between the ankle-to-arm systolic blood pressure ratio of normals and abnormals as measured by Doppler ultrasound with 0.96 as the dividing line, no false positives and only 11% false negatives were found. However, there was a large overlap for many parameters calculated from the velocity curve. The general morphological aspect of the velocity curve shows a better diagnostic performance than the calculated parameters of this curve: a monophasis curve had an 85% chance of being normal. The ankle segmental plethysmogram yielded only 5% false negatives, but 20% false positives; moreover, a biphasic curve has a 90% chance of being normal. Thus large-scale screening in clinical practice or in epidemiologic studies can best be done by Doppler pressure measurements; the velocity curve performs less satisfactorily. Segmental plethysmography is more sensitive, but it yields more false positive results.

Blood Pressure↗
PubMed1979

Is blood pressure variability related to activity of the sympathetic system?

1. In 70 patients with untreated essential hypertension, blood pressure variability was correlated to plasma catecholamines and to the response of blood pressure and peripheral flow to cold pressure and handgrip tests. 2. Supine blood pressure was recorded every 5 min, during 3 h. Variability was defined as the standard deviation of the mean of the readings in that period. 3. Blood pressure variability is positively and significantly correlated to the level of pressure and to age. 4. No significant correlation could be found with plasma catecholamines and sympathetic function tests. 5. It is concluded that blood pressure variability is related to the level of pressure but not to activity of the sympathetic nerves.

Blood Pressure↗
PubMed1979

Diagnostic work-up of patients with intermittent claudication.

In this paper a number of techniques are described that provide information concerning the functional disturbances caused by anatomic lesions within the vascular system in patients with intermittent claudication. These techniques are part of a currently growing entity that is called the "Vascular Laboratory". Main characteristics of these techniques are that they are painless, atraumatic and without any danger to the patient. Therefore, they can both be used for diagnosis as well as for follow-up of the patients. Moreover, many of them are useful for detecting stenotic lesions at an early stage of evolution. In any patient with intermittent claudication, the walking distance, oscillography at rest and after exercise and systolic blood pressure determination should be performed. Segmental plethysmography is extremely sensitive mainly when performed together with systolic blood pressure determination. Venous occlusion plethysmography has been significantly improved in recent years and is capable of providing direct information concerning the circulation through the diseased limb. There seems to be tremendous improvement in the techniques using ultrasound allowing presently construction of an anatomic picture of the vessels (Ultrasonic arteriography).

Blood Pressure↗
PubMed1978

Effect of indoramin on finger blood flow in vasospastic patients.

The effect of indoramin on blood pressure, heart rate and finger blood flow was investigated in eleven patients with essential acrocyanosis. Indoramin 50 mg t.i.d. and placebo were administered for 6 weeks, in random order in a double blind, cross-over trial. In 8 of the 11 patients, finger blood flow, measured by venous occlusion plethysmography was higher and resistance was lower with indoramin. There was no significant change in blood pressure or heart rate. Thus, indoramin may be useful when a decrease in alpha-adrenoreceptor tone in the fingers is desirable.

Blood Pressure↗
PubMed1978

Effect of selective and non-selective beta-adrenoreceptor blockade on calf blood flow in hypertensive patients.

1. Dose-response curves of isoprenaline were constructed in nine hypertensive patients before and after either propranolol or metoprolol. 2. The decrease of diastolic blood pressure and increase of heart rate with isoprenaline were significantly more inhibited by propranolol than by metoprolol. 3. The increase in calf blood flow with isoprenaline was significantly more depressed after propranolol than after metoprolol. 4. The results suggest that the response of the vessels in the limbs to sympathetic stimulation is much less affected after metoprolol than after propranolol.

Blood Pressure↗
PubMed1977

Effect of beta-adrenergic blockade on blood pressure variation in patients with moderate hypertension.

The effect of beta-adrenergic blockade on blood pressure variation was studied in ten patients with moderate hypertension. Supine systolic and diastolic blood pressures were measured every 5 min during six hours sessions, using an ultrasonic method. Systolic and diastolic variation in each six hour session was defined as the standard deviation of the mean of systolic and diastolic readings made in that period. After 3 weeks of single-blind placebo, a 12 week double-blind randomized crossover study was initiated with placebo (6 weeks) and atenolol (100 mg b.i.d. for 3 weeks and 200 mg b.i.d. for 3 weeks). Systolic and diastolic blood pressure and heart rate decreased significantly (p less than 0.01) during atenolol treatment. Diastolic variation did not change significantly, whereas systolic variation decreased slightly but significantly (p less than 0.05) when expressed in absolute values, but not when expressed as a percentage of systolic blood pressure. It is concluded that beta-adrenergic blockade decreases blood pressure and heart rate without causing significant changes in spontaneous systolic or diastolic variation.

Atenolol↗
PubMed1977

Diagnosis of myocardial infarction by the orthogonal vectorcardiogram.

From the literature concerning the electrocardiological diagnosis of myocardial infarction, data are reviewed illustrating the role of the scalar orthogonal approach by the Frank system. Special attention is drawn to the Q/R ratio as a parameter. Criteria for the most frequent differential diagnoses are summarized in a practical way. The importance of the concepts sensitivity and specificity is stressed, while statistical methods for establishing the value of parameters are discussed. Results of multivariate analysis are indicated.

Analysis of Variance↗
PubMed1976

Neurogenic influences on blood pressure and vascular tone from peripheral receptors during muscular contraction.

In anesthetized dogs, contraction of the muscles of the thigh was elicited either by applying electrodes in the muscles or by stimulation of the spinal ventral roots. The carotid sinuses were isolated; the vagi and the depressor nerves cut. Rhythmic muscular contraction caused hypotension and vasodilatation; tetanic contraction caused hypertension and vasoconstriction. These responses are of reflexogenic origin: the afferent pathway is in the somatic nerves, the efferent pathway in the sympathetic nerves.

Animals↗
PubMed1975

Control of high and low blood pressure in the dog by aortic and sinus nerves.

1. Changes in afferent activity in the aortic and sinus nerves with alterations of blood pressure were studied in anesthetized dogs. Mean aortic blood pressure was changed from 220 to 50 mmHg by using a pressurized reservoir connected to the abdominal aorta. 2. The stimulus--response curve (defined by measuring the mean impulse frequency at various pressures) from both nerves was S-shaped; the curve for the aortic nerve was shifted to the right of the sinus nerve curve. 3. In the dog, the aortic arch baroreceptors act predominantly as an anti-hypertensive mechanism; at lower pressures, the major control occurs through the sinus baroreflex.

Afferent Pathways↗