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Biomedical subjects

F Kemp

Publications and source records attributed to F Kemp.

12 recordsLinked to original sources
PubMed1994

Increased blood pressure variability during 24h blood pressure monitoring as an early sign of autonomic dysfunction in non-insulin-dependent diabetics.

To evaluate the presence of early autonomic dysfunction in non-insulin-dependent diabetics we examined 24h control of blood pressure (1/4 hourly readings day and 1/2 hourly at night, using TM 2420) in 20 non-insulin-dependent diabetics, controlled only on diet or oral hypoglycaemics and 20 age/sex/BP matched non-diabetics selected from a random population survey. The two groups were aged 52 +/- 9 years and 53 +/- 8 years, respectively. Both groups included normotensives and mild hypertensives in equal numbers but none was on antihypertensive treatment. The groups were well matched for daytime systolic blood pressure (SBP; 132.2 +/- 11.4 vs. 131.2 +/- 10.3) and diastolic blood pressure (DBP; 82.1 +/- 8.3 vs. 81.1 +/- 7.0). The diabetics had a significantly greater heart rate (HR) both during the day (79.6 +/- 9.5 vs. 72.3 +/- 8.8: P = 0.015) and during sleep (67.7 +/- 6.8 vs. 62.5 +/- 8.9). There was increased BP variability in the diabetics during the day (standard deviation of SBP; 16.9 +/- 6.2 vs. 13.3 +/- 4.7: P < 0.05) but the difference for DBP variability was not significant. The day-night difference for SBP, DBP, HR and HR variability was the same in both groups. We conclude that in these patients there was evidence for an alteration in BP variability (which may reflect baroreflex insensitivity) at a stage where there was no alteration in day-night rhythms of BP or HR. The increased HR both at day and night may also reflect baroreflex dysfunction and/or sympathovagal imbalance.(ABSTRACT TRUNCATED AT 250 WORDS)

Autonomic Nervous System↗
PubMed1994

How effective is training for blood pressure measurement?

Monitoring blood pressure is a procedure most medical and nursing staff frequently perform, and forms the basis for many decisions about treatment. This study, however, highlights a disturbing lack of clarity among practitioners about how the procedure should be performed.

Blood Pressure Determination↗
PubMed1993

Effects of TENS and topical skin anesthesia on soleus H-reflex and the concomitant influence of skin/muscle temperature.

The purpose of this study was to determine, in ten healthy subjects, the extent of soleus motoneuronal excitability during conditions of increased (transcutaneous electrical nerve stimulation [TENS]), decreased (Xylocaine [lidocaine]a anaesthesia) and normal (placebo anaesthesia) cutaneous inputs. Increased cutaneous activity was evoked using a TENS unit, with the two pairs of electrodes placed respectively over the Achilles (S2 dermatome) and tibialis anterior (L5 dermatome) tendons. Experimental and placebo topical anaesthesia were obtained after rubbing Xylocaine (5%) and Vaselineb ointment, respectively, on the skin surface overlying the Achilles tendon. Sets of ten H-responses (Hmax/2) were evoked at a frequency of 1 shock/30s and averaged at regular time intervals before, during and after the testing conditions. The results showed a gradual increase (up to 40% after 20 minutes) of H-reflex amplitude during TENS regardless of whether it was applied on the L5 or S2 dermatome. Furthermore, placebo anesthesia (Vaseline) caused the same gradual facilitatory response (up to 100% after 50 minutes) as that obtained during Xylocaine anaesthesia. Power spectral analysis of the H-responses obtained over time showed that the increase in the peak-to-peak H-response value was accompanied by a shift of the spectral content toward low frequencies. This shift occurred concomitantly with a cooling of the skin overlying the soleus muscle.

Administration, Topical↗
PubMed1992

Effects of essential hypertension and antihypertensive medications on sweat formation.

OBJECTIVE: Sweat volume and ionic composition depend to a large extent upon the cytosolic free calcium level in secretory sweat cells and sodium and potassium transport in the reabsorptive sweat duct. Since essential hypertension and its treatment with antihypertensive drugs is likely to be associated with altered cellular ionic regulation, the objective of this research was to explore sweat formation and sweat parameters in hypertensive and normotensive subjects. DESIGN: Black and white hypertensive and normotensive subjects of both genders were studied. Essential hypertensives were on or off antihypertensive medication. METHODS: Pilocarpine iontophoresis was used to induce sweat in a 5-cm2 area of the middle forearm. Sweat was analyzed for volume, sodium and potassium concentrations. RESULTS: Females demonstrated lower sweat volumes after pilocarpine stimulation than males. Untreated hypertensive white males exhibited a higher pilocarpine-induced sweat volume and sweat sodium excretion than normotensive white males, whilst hypertensive white males on antihypertensive medication showed a lower sweat volume and sweat sodium excretion than both normotensive white males and untreated essential hypertensive white males. Although untreated hypertensive white females did not show significant alterations in sweat parameters, treated hypertensive white females exhibited lower sweat volume and sweat sodium excretion than both the normotensive and untreated essential hypertensive white females. These hypertension and drug related alterations were not present in hypertensive black males and females. CONCLUSIONS: The results are consistent with the heterogeneous nature of essential hypertension and the diversity of the response to antihypertensive therapy. They suggest that the effect of antihypertensive medication on sweat formation is mediated through cytosolic free calcium.

Adult↗
PubMed1990

Micronutrient status and human immunodeficiency virus (HIV) infection.

This study surveyed serum concentrations of vitamins, electrolytes, and trace elements in subjects seropositive for HIV-1 by ELISA and confirmatory Western blot. Thirty subjects (26 males, 4 females) were recruited at a hospital clinic. Seventeen were classified as having mild or severe ARC (AIDS-related complex), 7 had AIDS, and 6 were asymptomatic. Eight had experienced weight loss of 10 pounds or more in the past 6 months. Most (93%) were anergic to skin test antigens. Percentages of subjects with below normal plasma concentrations include: zinc-30%, calcium-27%, magnesium-30%, carotenes-31%, total choline-50%, and ascorbate-27%. Eighty-seven percent of the subjects had at least one abnormally low value. Percentages with above normal values include: folate-37% and carnitine-37%. Some subjects with above normal values for plasma vitamins reported self-supplementation, usually with large doses. The results suggest that one or more abnormally low concentrations of the plasma micronutrients studied here are likely to be present in the majority of HIV seropositive patients.

AIDS-Related Complex↗
PubMed1984

Increased forearm vascular resistance after dopamine blockade.

The peripheral haemodynamic effects of a 40 mg intravenous injection of domperidone (a dopamine antagonist) have been studied in 10 normal subjects. In four subjects domperidone was infused directly into the brachial artery and the effects on forearm blood flow were measured. When administered systemically, domperidone significantly decreased forearm blood flow by 9% (P less than 0.01) and significantly increased calculated forearm vascular resistance by 11% (P less than 0.01). The drug produced no measurable changes in forearm blood flow at any dose when infused directly into the brachial artery. A further study was carried out into the effects of a systemic injection of domperidone on peripheral sympathetic tone. Reduction of sympathetic tone in the forearm was achieved by passively raising the legs of eight recumbent subjects. Before domperidone administration, passive leg elevation significantly increased forearm blood flow by 39% and decreased forearm vascular resistance by 13%. After drug administration the absolute values of vascular resistance increased and the changes between the supine and elevated position values when compared with those of the corresponding values prior to drug administration were significantly lower. These results suggest that the role of domperidone in increasing peripheral vascular tone is unlikely to be mediated by a direct local effect on peripheral resistance vessels. Any effect the drug may have is suggested to be mediated via a central control mechanism.

Adult↗