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SODIUM EXCRETION AND SYMPATHETIC ACTIVITY IN RELATION TO SEVERITY OF HYPERTENSIVE DISEASE
471 SODIUM EXCRETION AND SYMPATHETIC ACTIVITY IN RELATION TO SEVERITY OF HYPERTENSIVE DISEASE
SIR,-Berglund et al.’ report that when diagnosing essential hypotension their limits-175/115 mm Hg on two separate occasions two weeks apart, the measurements being done between 4.30 P.M. and 7.30 P.M.—corresponded to limits of 162/101 mm Hg when the measurements are taken on the same men at 8.00 A.M. The variation in blood-pressure with time of day reported in this paper is substantially greater than the 3-5 mm Hg reported in the National Health Survey publication.,
The mean change in systolic and diastolic blood pressure by time of home screen and time of the re-examination, shows that on re-examination blood-pressure fell in all four cells in table u for both systolic and diastolic pressures. The time-ofday effect is probably small relative to the regression effect. This would imply that the differences observed by Berglund et al. are largely due to regression toward the mean rather than variation in blood-pressure with time of day. H.D.F.P. Cooperative Study School of Public Health,
University of Texas, Houston, Texas 77025, U.S.A.
These findings are important both for patient care and for community-based studies of hypertension. To investigate this point further the average diastolic and systolic blood-pressures for subjects participating in the Hypertension Detection and Follow-up Program (H.D.F.P.) were computed for subjects
screened between 9.30-10.30
A.M.
and 4.30-5.30
P.M.
T.4BLE I-MEAN BLOOD-PRESSURE
IN
SUBJECTS
SCREENED
IN
THE
MORNING OR AFTERNOON
ROBERT J. HARDY GARY R. CUTTER C. MORTON HAWKINS
PITYRIASIS VERSICOLOR ALBA (SPECKLED TORSO SYNDROME) AND MEDITERRANEAN HOLIDAYS
Table
gives the mean blood-pressure, with the sample size in each category in parentheses. We have selected the morning and afternoon times which correspond as closely as possible to those reported by Berglund et al. I
Group,
SIR,-The attraction of Mediterranean beaches for North West European holidaymakers is largely responsible for the increased frequency with which pityriasis (tinea) versicolor alba is now being met with in the U.K. This is the name given to the clinical variant of pityriasis versicolor characterised by white macules at sites of infection instead of those with the more usual khaki or fawn colour. The lesions are usually symdistributed as they are nearly always more profuse the upper trunk and arms, the "speckled torso syndrome" would seem to be an appropriate name for the condition. Lesions however, may be restricted to quite small areas, such as one shoulder. No age is immune, the youngest patient seen so far is a 27-month-old girl whose speckling followed her first summer holiday in Portugal last year, but it is adolescents and young adults of both sexes who are more likely to be affected (e.g., the three members of a London football club who were worried about the speckling that followed their tour of Madagascar). This is not surprising because Pityrosporon orbiculare, the yeast-like microbe responsible for the infection, is virtually ubiquitous, and Roberts’ found that it was carried by over 90% of adolescents and adults studied in Cambridge. Sweating is the principal factor in precipitating infection as well as determining the extent to which the skin is involved. Ultraviolet light, especially that of sunshine, is lethal to the organism, and this is well demonstrated in those patients who display clinical and mycological evidence of infection on areas shielded from the sun by the brassière or bathing trunks while the exposed de-pigmented lesions are clinically, mycologically, and histologically free from infection. Ultrastructural studies from Paris, and those reported by A. L. Boiron from Bordeaux at the recent meeting of 1’Association des Dermatologistes et Syphiligraphes de Langue Française at Ajaccio, throw light on this apparent paradox. These show that there is a profound disturbance in the physiology of the melanocytes in the depigmented lesions, with striking reduction in, or total cessation of melanin production, associated with structural changes in the melanosine. These are small and round with a granular or lamellar matrix. The melanocytes lose contact with neighbouring cells (keratinocytes) ; indeed the only cells in contact with them are macrophages which have migrated from the dermis to occupy an electrolucent dilated space above the basilar membrane. Each macrophage is in close contact with an inactive melanocyte. This suggests not only that toxins from this microbe activate macrophages directly or indirectly, as in other infections, but also that some of these may have the property of inhibiting or disturbing melanin production when in contact with melanocytes. These changes may persist indefinitely in some individuals, although prompt repigmentation is the rule when the
metrically on
The variation in daily blood-pressures in the H.D.F.P. data does not reflect the same degree of variation with time of day that was reported by Berglund et al. but accords more closely with the National Health Survey publication. In part, the results reported by Berglund et al. on 19 persons with essential hypertension may be due to "regression toward the mean" since these subjects were selected by their screening procedure. The difference between the afternoon blood-pressures during screening and the morning blood-pressures during their re-examination is due to variation of blood-pressure with time of day and a regression effect due to the selection procedure used to screen the subjects in the afternoon. If the regression effect is large one would expect subjects screened in a similar way in the morning to show this same regression effect if re-examined in the afternoon. In the H.D.F.P. subjects were selected for a clinic visit if their diastolic blood-pressure in their home was greater than 95 mm Hg; hence, one would expect the regression effect to be larger in the diastolic than the systolic pressure. We have selected subjects who were screened in their home between 9.00 and 11.00 A.M. or between 3.00 and 5.00 P.M. The subjects subsequently had a visit to one of the H.D.F.P. clinics between 9.00 and 11.00 A.M. or between 3.00 and 5.00 P.M. table n). aiBLE II—CHANGES IN BLOOD-PRESSURE FROM HOME SCREEN TO CLINIC
RE-EXAMINATION
und, G., Wtkstrand, J., Wallentin, I., Wilhelmsen,
L.
Lancet, 1976, i,
324
nal Health Survey. Public Health Service Publications .:, no 13 Washington, D.C., 1964.
no.
1000, series
1. Roberts, S. O. B. Br. J. Derm. 1969, 81, 315. 2. Grupper, C., Cesarini, J. P., Pruinéras, M. Bull. Soc.
82, 114.
fr.
Derm.
Syph. 1975,
SIR,-Berglund et al.’ report that when diagnosing essential hypotension their limits-175/115 mm Hg on two separate occasions two weeks apart, the measurements being done between 4.30 P.M. and 7.30 P.M.—corresponded to limits of 162/101 mm Hg when the measurements are taken on the same men at 8.00 A.M. The variation in blood-pressure with time of day reported in this paper is substantially greater than the 3-5 mm Hg reported in the National Health Survey publication.,
The mean change in systolic and diastolic blood pressure by time of home screen and time of the re-examination, shows that on re-examination blood-pressure fell in all four cells in table u for both systolic and diastolic pressures. The time-ofday effect is probably small relative to the regression effect. This would imply that the differences observed by Berglund et al. are largely due to regression toward the mean rather than variation in blood-pressure with time of day. H.D.F.P. Cooperative Study School of Public Health,
University of Texas, Houston, Texas 77025, U.S.A.
These findings are important both for patient care and for community-based studies of hypertension. To investigate this point further the average diastolic and systolic blood-pressures for subjects participating in the Hypertension Detection and Follow-up Program (H.D.F.P.) were computed for subjects
screened between 9.30-10.30
A.M.
and 4.30-5.30
P.M.
T.4BLE I-MEAN BLOOD-PRESSURE
IN
SUBJECTS
SCREENED
IN
THE
MORNING OR AFTERNOON
ROBERT J. HARDY GARY R. CUTTER C. MORTON HAWKINS
PITYRIASIS VERSICOLOR ALBA (SPECKLED TORSO SYNDROME) AND MEDITERRANEAN HOLIDAYS
Table
gives the mean blood-pressure, with the sample size in each category in parentheses. We have selected the morning and afternoon times which correspond as closely as possible to those reported by Berglund et al. I
Group,
SIR,-The attraction of Mediterranean beaches for North West European holidaymakers is largely responsible for the increased frequency with which pityriasis (tinea) versicolor alba is now being met with in the U.K. This is the name given to the clinical variant of pityriasis versicolor characterised by white macules at sites of infection instead of those with the more usual khaki or fawn colour. The lesions are usually symdistributed as they are nearly always more profuse the upper trunk and arms, the "speckled torso syndrome" would seem to be an appropriate name for the condition. Lesions however, may be restricted to quite small areas, such as one shoulder. No age is immune, the youngest patient seen so far is a 27-month-old girl whose speckling followed her first summer holiday in Portugal last year, but it is adolescents and young adults of both sexes who are more likely to be affected (e.g., the three members of a London football club who were worried about the speckling that followed their tour of Madagascar). This is not surprising because Pityrosporon orbiculare, the yeast-like microbe responsible for the infection, is virtually ubiquitous, and Roberts’ found that it was carried by over 90% of adolescents and adults studied in Cambridge. Sweating is the principal factor in precipitating infection as well as determining the extent to which the skin is involved. Ultraviolet light, especially that of sunshine, is lethal to the organism, and this is well demonstrated in those patients who display clinical and mycological evidence of infection on areas shielded from the sun by the brassière or bathing trunks while the exposed de-pigmented lesions are clinically, mycologically, and histologically free from infection. Ultrastructural studies from Paris, and those reported by A. L. Boiron from Bordeaux at the recent meeting of 1’Association des Dermatologistes et Syphiligraphes de Langue Française at Ajaccio, throw light on this apparent paradox. These show that there is a profound disturbance in the physiology of the melanocytes in the depigmented lesions, with striking reduction in, or total cessation of melanin production, associated with structural changes in the melanosine. These are small and round with a granular or lamellar matrix. The melanocytes lose contact with neighbouring cells (keratinocytes) ; indeed the only cells in contact with them are macrophages which have migrated from the dermis to occupy an electrolucent dilated space above the basilar membrane. Each macrophage is in close contact with an inactive melanocyte. This suggests not only that toxins from this microbe activate macrophages directly or indirectly, as in other infections, but also that some of these may have the property of inhibiting or disturbing melanin production when in contact with melanocytes. These changes may persist indefinitely in some individuals, although prompt repigmentation is the rule when the
metrically on
The variation in daily blood-pressures in the H.D.F.P. data does not reflect the same degree of variation with time of day that was reported by Berglund et al. but accords more closely with the National Health Survey publication. In part, the results reported by Berglund et al. on 19 persons with essential hypertension may be due to "regression toward the mean" since these subjects were selected by their screening procedure. The difference between the afternoon blood-pressures during screening and the morning blood-pressures during their re-examination is due to variation of blood-pressure with time of day and a regression effect due to the selection procedure used to screen the subjects in the afternoon. If the regression effect is large one would expect subjects screened in a similar way in the morning to show this same regression effect if re-examined in the afternoon. In the H.D.F.P. subjects were selected for a clinic visit if their diastolic blood-pressure in their home was greater than 95 mm Hg; hence, one would expect the regression effect to be larger in the diastolic than the systolic pressure. We have selected subjects who were screened in their home between 9.00 and 11.00 A.M. or between 3.00 and 5.00 P.M. The subjects subsequently had a visit to one of the H.D.F.P. clinics between 9.00 and 11.00 A.M. or between 3.00 and 5.00 P.M. table n). aiBLE II—CHANGES IN BLOOD-PRESSURE FROM HOME SCREEN TO CLINIC
RE-EXAMINATION
und, G., Wtkstrand, J., Wallentin, I., Wilhelmsen,
L.
Lancet, 1976, i,
324
nal Health Survey. Public Health Service Publications .:, no 13 Washington, D.C., 1964.
no.
1000, series
1. Roberts, S. O. B. Br. J. Derm. 1969, 81, 315. 2. Grupper, C., Cesarini, J. P., Pruinéras, M. Bull. Soc.
82, 114.
fr.
Derm.
Syph. 1975,