Migration and geographic variations in blood pressure in Britain.

OBJECTIVE--To evaluate the relative contributions of factors acting at different stages in life to regional differences in adult blood pressure. DESIGN--Prospective cohort study (British regional heart study). SETTING--One general practice in each of 24 towns in Britain. SUBJECTS--7735 Men aged 40-59 years when screened in 1978-80 whose geographic zone of birth and zone of examination were classified as south of England, midlands and Wales, north of England, and Scotland. Non-migrants (n = 3144) were born in the town where they were examined; internal migrants (n = 4147) were born in Great Britain but not in the town where they were examined; and international migrants (n = 422) were born outside Great Britain. MAIN OUTCOME MEASURES--Systolic and diastolic blood pressures and height. RESULTS--Regardless of where they were born, men living in the south of England had lower mean blood pressures than men living in Scotland (142.5/80.1 v 148.1/85.2 mm Hg). The effects of the place of birth and place of examination on adult blood pressure were examined in a multiple regression model. For internal migrants the modelled increase in mean systolic blood pressure across adjacent zones of examination was 2.1 mm Hg (95% confidence interval 1.3 to 2.9); for adjacent zones of birth the corresponding increase was 0.1 mm Hg (-0.7 to 0.7). The place of examination seemed to be a far more important determinant of mean adult blood pressure than the place of birth. Height is an accepted marker of genetic and early life influences. Regional differences in height were therefore analysed to test whether the multiple regression model could correctly distinguish between the influence of place of birth and place of examination. As expected, men born in Scotland were shorter on average than men born in the south of England irrespective of where they lived in Britain (172.6 cm v 175.1 cm for internal migrants). CONCLUSION--Regional variations in blood pressure were strongly influenced by where the men had lived for most of their adult lives rather than by where they were born and brought up. Among middle aged men, factors acting in adult life seemed to be more important determinants of regional differences in blood pressure than those acting early in life such as genetic inheritance, intrauterine environment, and childhood experience.     

A dampening effect of pulse interval variability on blood pressure variations with respect to primary variability in blood pressure during exercise

The correlation between baroreflex sensitivity (BRS) and the spectrum component at a frequency of 0.1 Hz of pulse intervals (PI) and systolic blood pressure (SBP) was studied. SBP and PI of 51 subjects were recorded beat-to-beat at rest (3 min), during exercise (0.5 W/kg of body weight, 9 min), and at rest (6 min) after exercise. BRS was determined by a spectral method (a modified alpha index technique). The subjects were divided into groups according to the spectral amplitude of SBP at a frequency of 0.1 Hz. The following limits of amplitude (in mm Hg) were used: very high > 5.4 (VH); high 5.4 > H > 3 (H); medium 3 > M > 2 (M), low < 2 (L). We analyzed the relationships between 0.1 Hz variability in PI and BRS at rest, during the exercise and during recovery in subgroups VH, H, M, L. The 0.1 Hz variability of PI increased significantly with increasing BRS in each of the groups with identical 0.1 Hz variability in SBP. This relationship was shifted to the lower values of PI variability at the same BRS with a decrease in SBP variability. The primary SBP variability increased during exercise. The interrelationship between the variability of SBP, PI and BRS was identical at rest and during exercise. A causal interrelationship between the 0.1 Hz variability of SBP and PI, and BRS was shown. During exercise, the increasing primary variability in SBP due to sympathetic activation was present, but it did not change the relationship between variability in pulse intervals and BRS.     

William James, faith, and the placebo effect

Long considered a fact of medicine and of clinical investigation, the placebo effect has recently been challenged. The thought of the great American psychologist and philosopher William James, particularly his understanding of the practical value of faith, helps to illuminate the nature of the placebo effect and the implications of this puzzling phenomenon for understanding healing and the practice of medicine.     

Biofeedback and the placebo effect

This article reviews the role of positive expectations, including those engendered by placebos, in symptom relief following medical and surgical procedures, and psychotherapy. Viewing biofeedback as instrument-aided psychotherapy, its procedures are considered in the light of their ability to mobilize the same healing forces as all forms of psychotherapy, with some implications for promising directions of biofeedback research.Slightly modified from an invited address to the Biofeedback Society on March 15, 1981 in Louisville, Kentucky.     

Semiotics and the placebo effect

Despite substantial progress in elucidating its neurobiological mechanisms, theoretical understanding of the placebo effect is poorly developed. Application of the semiotic theory developed by the American philosopher Charles Peirce offers a promising account of placebo effects as involving the apprehension and response to signs. The semiotic approach dovetails with the various psychological mechanisms invoked to account for placebo effects, such as conditioning and expectation, and bridges the biological and cultural dimensions of this fascinating phenomenon.     

Circadian variations of catecholamines and blood pressure in patients with pseudohypoparathyroidism and hypertension

The relationship between 24-h recumbent blood pressure levels and secretory patterns of catecholamines was investigated in 4 patients with pseudohypoparathyroidism (PsHP) and hypertension and in 9 patients with essential hypertension. A clear circadian rhythm of blood pressure and catecholamines was documented in both groups with lowest levels of blood pressures and catecholamines occurring during sleep. During the 24-h period of recumbency mean arterial blood pressure (MAP) was correlated (r = 0.63, p less than or equal to 0.01) with plasma norepinephrine (N) in the patients with essential hypertension, but this correlation was weaker in patients with PsHP (r = 0.38, p less than or equal to 0.05). MAP was more closely related to plasma epinephrine (E) (r = 0.62, p less than or equal to 0.01) than to plasma NE in patients with PsHP. Plasma NE and E levels were considerably lower in patients with PsHP than in patients with essential hypertension throughout the 24-h recumbent period. The sleep-related decline in blood pressure and NE was less than in patients with essential hypertension. These results suggest that while the sympathetic nervous system may have a role in hour-to-hour maintenance of blood pressure in patients with PsHP and hypertension, it does not appear to be responsible for the elevated arterial pressure in these patients. Factors other than those investigated, such as obesity, alterations in sodium homeostasis of refractoriness of the vascular smooth muscle to the vasodilatory effect of PTH may be involved in the pathogenesis of hypertension in PsHP.     

The placebo effect: how the subconscious fits in

The placebo effect is very well known, being replicated in many scientific studies. At the same time, its exact mechanisms still remain unknown. Quite a few hypothetical explanations for the placebo effect have been suggested, including faith, belief, hope, classical conditioning, conscious/subconscious expectation, endorphins, and the meaning response. This article argues that all these explanations may boil down to autosuggestion, in the sense of "communication with the subconscious." An important implication of this is that the placebo effect can in principle be used effectively without the placebo itself, through a direct use of autosuggestion. The benefits of such a strategy are clear: fewer side effects from medications, huge cost savings, no deception of patients, relief of burden on the physician's time, and healing in domains where medication or other therapies are problematic.     

Monthly variations in drug-induced gastric ulcers in rats

Clinical evidence suggests that there may be some relationship between the occurrence of peptic ulcers and the season of the year. As little experimental work has been carried out on this subject, three drugs commonly used to induce experimental ulcers in rats (acetylsalicylic acid, 300 mg/kg; phenylbutazone, 200 mg/kg; reserpine, 10 mg/kg) were tested every month for one year under standardised experimental conditions (T_a, RH, LD 12:12). In rats given phenylbutazone the maximum area of ulceration was found in October and December, and in rats given acetylsalicylic acid in February and March. In rats given reserpine, there were no significant monthly variations. An influence of climatic factors on ulcer induction cannot be completely excluded. Endogenous conditions might also account for the monthly differences in ulceration.     

The effects of caffeine on plasma MHPG,subjective anxiety,autonomic symptoms and blood pressure in healthy humans

The effects of oral administration of caffeine (10 mg/kg) on plasma free 3-methoxy-4-hydroxyphenylethyleneglycol (MHPG) levels, behavioral ratings, blood pressure, and autonomic symptoms was determined in eleven healthy subjects. Caffeine produced robust increases in subject rated anxiety and nervousness and small elevations in blood pressure and a decrease in heart rate. Caffeine did not alter plasma MHPG in a consistent fashion and there was no correlation between changes in plasma MHPG and changes in anxiety or other ratings. Caffeine may produce symptoms of anxiety-nervousness without increasing central norepinephrine turnover.     

Randomised,double blind placebo controlled trial of pentoxifylline in the treatment of venous leg ulcers

ObjectiveTo determine whether pentoxifylline 400 mg (Trental 400) taken orally three times daily, in addition to ambulatory compression bandages and dressings, improves the healing rate of pure venous ulcers.DesignRandomised, double blind placebo controlled trial, parallel group study of factorial design, permitting the simultaneous evaluation of alternative pharmaceutical, bandaging, and dressings materials.SettingLeg ulcer clinics of a teaching and a district general hospital in southern Scotland.Participants200 patients with confirmed venous ulcers and in whom other major causal factors were excluded.InterventionsPentoxifylline 400 mg three times daily or placebo.ResultsComplete healing occurred in 65 of the 101 (64%) patients receiving pentoxifylline and 52 of the 99 (53%) patients receiving placebo.ConclusionsThe difference in the healing rates between patients taking pentoxifylline and those taking placebo did not reach statistical significance.

Key messages

• Leg ulcers cost the NHS around £400 million per annum
• 50%-75% of venous leg ulcers can be succesfully treated with dressings and compression bandages but take many months to heal
• A drug that reduced the healing time of venous ulcers would be useful, although no agent has been proved to be effective to date
• Trials with pentoxifylline, a vasoactive drug used in the treatment of peripheral vascular diseases, as an adjunct to the treatment of venous ulcers have been inconclusive
• At the 5% level, pentoxifylline had a non-significant effect on healing rates of pure venous ulcers

     

Tissue expansion in the treatment of pressure ulcers

The authors report their experience using skin expanders in 11 patients with severe bed sores. The expanders, with different volumes, from 250 to 1000 cc, were generally overfilled using the cutaneous tonometer. In fact, with the information revealed by this apparatus on the skin in expansion, the authors were able to reduce the filling intervals without risking ulceration. In their experience, the results obtained were satisfactory: All patients treated achieved surgical recovery. The authors see a wide future for skin-expander use in pressure-ulcer treatment. They have a working hypothesis about using expanders to progressively advance sensitive skin in areas subject to ulceration. This hypothesis is based on the possibility of reexpanding the same flap several times, as has been seen in the treatment of other types of pathology.