Numerical simulation of the general circulation of the atmosphere of Titan

The atmospheric circulation of Titan is investigated with a general circulation model. The representation of the large-scale dynamics is based on a grid point model developed and used at Laboratoire de Météorologie Dynamique for climate studies. The code also includes an accurate representation of radiative heating and cooling by molecular gases and haze as well as a parametrization of the vertical turbulent mixing of momentum and potential temperature. Long-term simulations of the atmospheric circulation are presented. Starting from a state of rest, the model spontaneously produces a strong superrotation with prograde equatorial winds (i.e., in the same sense as the assumed rotation of the solid body) increasing from the surface to reach 100 m sec-1 near the 1-mbar pressure level. Those equatorial winds are in very good agreement with some indirect observations, especially those of the 1989 occultation of Star 28-Sgr by Titan. On the other hand, the model simulates latitudinal temperature contrasts in the stratosphere that are significantly weaker than those observed by Voyager 1 which, we suggest, may be partly due to the nonrepresentation of the spatial and temporal variations of the abundances of molecular species and haze. We present diagnostics of the simulated atmospheric circulation underlying the importance of the seasonal cycle and a tentative explanation for the creation and maintenance of the atmospheric superrotation based on a careful angular momentum budget.

Titan's atmosphere composition: certainties and speculations

Firm results concerning the thermal structure, the composition, the seasonal effects of the atmosphere of Titan, as well as the superotation of its stratosphere are reviewed. The nature of the surface of the satellite, the possible presence of argon in the atmosphere and the structure and composition of clouds and aerosols are, among other topics, still speculative. The implications of the observed deuterium enrichment on the origin of ices in the outer part of the nebula are controversial.

Chemical and thermal response of Jupiter's atmosphere following the impact of comet Shoemaker-Levy 9

In July 1994, the collisions of the fragments of comet Shoemaker-Levy 9 with Jupiter resulted in dramatic changes in the planet's atmosphere. Observations of the events suggest that the composition and thermal properties of the atmosphere were considerably modified at the impact sites, with the changes persisting for times lasting from minutes to weeks (see, for example, refs 1-4). Here we report observations of the impact sites at millimetre wave-lengths, which reveal strong emission lines associated with carbon monoxide, carbonyl sulphide and carbon monosulphide. The abundance of carbon monoxide in the jovian atmosphere is normally very low; carbonyl sulphide and carbon monosulphide, on the other hand, have not hitherto been detected. We find that the largest fragments (G and K) each produced approximately 10(14) g of carbon monoxide, 3 x 10(12) g of carbonyl sulphide and 3 x 10(11) g of carbon monosulphide, most probably by shock-induced chemical reactions. Our observations also place firm constraints on the thermal response of Jupiter's stratosphere to the impacts.

Photochemical modeling of Titan's atmosphere

We have developed a new photochemical model of Titan's atmosphere which includes all the important compounds and reactions in spherical geometry from the surface to 1240 km. Compared to the previous model of Yung et al. (1984, Astrophys. J. Suppl. 55, 465-506), the most significant recent change in the reactions used is the updated methane photodissociation scheme (Mordaunt et al. 1993, J. Chem. Phys. 98(3), 2054-2065). Moreover, the transfer of the solar radiation in the atmosphere and the photolysis rates have been calculated by using a Monte Carlo code. Finally, the eddy diffusion coefficient profile is adjusted in order to fit the mean vertical distribution of HCN retrieved from millimeter groundbased observations of Tanguy et al. (1990, Icarus, 85, 43-57) using new values for the boundary flux of atomic nitrogen (Strobel et al. 1992, Icarus 100, 512-526). We have run the model in both steady-state and diurnal modes, with 62 speices involved in 249 reactions. There is little difference between diurnal and steady-state results. Overall our results are in a closer agreement with the abundances inferred from the Voyager infrared measurements at the equator than the Yung et al. results. We find that the catalytic scheme for H recombination invoked by Yung et al. only slightly improves the model results and we conclude that this scheme is not essential to fit observations.

[Cardiac autonomic neuropathy. Current realities and future outlook]

Cardiac autonomic neuropathy frequently affects Type 1 and Type 2 diabetic patients. This disease is distinguished by visible clinical consequences which can be tragic. It can also worsen a number of degenerative complications. Therefore, cardiac autonomic neuropathy seems to play a deciding role in silent ischaemia and in dysregulations of blood pressure. Clinical explorations continue to be based on the tests validated by Ewing, but the development of simple and reliable techniques seems to be an objective the interest of which cannot escape any clinician.

Ambulatory blood pressure in diabetic subjects

Ambulatory blood pressure (ABP) was measured every 15 min for 24 h in 82 diabetic subjects aged 35 to 79 years and in 66 healthy controls having the same age and office blood pressure. The autonomic control in diabetic subjects was evaluated by the total score of five cardiovascular function tests (a high score means an autonomic neuropathy). The diurnal cycle of BP was assessed by the difference of BP between daytime and nighttime (delta BP = BP in the day - BP in the night). The variability of BP was evaluated by the standard deviations of the readings. Compared with control subjects, diabetic subjects had the same 24-h mean level of BP, a smaller delta BP, and an increased variability during the daytime; however, the differences were in the limit of statistical significance. Clearcut results were obtained in diabetic subjects with autonomic neuropathy. In the latter, the score of autonomic neuropathy was (1) negatively correlated to delta SBP (systolic) and delta DBP (diastolic) (r = 0.44, P = .0004 and r = 0.46, P = .0004, respectively) and (2) positively correlated to the variability of SBP and DBP during the daytime (r = 0.46, P .0004 and r = 0.29, P = .03, respectively). In diabetic subjects, mean level and variability of ABP were positively correlated to urinary microalbumin. The relationships were the most significant when one relates microalbuminuria to the level of SBP in the night (r = 0.42, P < .0003) and to the variability of SBP in the day (r = 0.32, P = .008).(ABSTRACT TRUNCATED AT 250 WORDS)

[Action of trandolapril on the blood glucose balance and microalbuminuria in hypertensive diabetics]

The aim of this study was to evaluate the action of trandolapril on blood glucose control and microalbuminuria in mild to moderate hypertensive in patients with non-insulin-dependent diabetes. Sixty-seven patients, aged between 33 and 79, were enrolled. After a two week placebo run-in period, treatment with trandolapril as monotherapy was given for 3 months. The dose of trandolapril was adjusted between 1 and 4 mg/day according to antihypertensive response. Patients were assessed clinically and by laboratory investigations each month. Two patients were excluded from efficacy analysis because of major protocol deviations. Mean DBP fell, under the influence of treatment, from 101 +/- 5 mmHg to 82 +/- 7 mmHg (p < 0.0001) and mean SBP from 171 +/- 9 mmHg tp 147 +/- 11 mmHG (p < 0.0001). At three months, 54 patients (84%) had a DBP < or = 90 mmHg. Microalbuminuria decreased significantly (p = 0.03) during treatment. Microalbuminuria returned to normal in 11 of the 13 patients in whom the baseline value was above 21 micrograms/min and increased to above normal in 2 of the 26 patients who had a normal baseline value. Blood glycosylated hemoglobin, fructosamine, glucose and creatinine, and creatinine clearance remained stable. Plasma potassium rose slightly in 7 patients. Six adverse events were reported (4 coughs, 1 peripheral edema, 1 plantar mal perforans). One patient died from pulmonary embolism. In conclusion, trandolapril is an effective antihypertensive agent in hypertensive diabetics. Trandolapril causes a significant decrease in microalbuminuria and does not interfere with blood glucose control in these patients.

Use of runs test to assess cardiovascular autonomic function in diabetic subjects

OBJECTIVE

We suggest a simple, noninvasive method to assess the autonomic function in diabetic subjects. The method requires only a monitoring of heart rate (HR) with subjects in the sitting position.

RESEARCH DESIGN AND METHODS

Sixty diabetic subjects, 44 men and 16 women, between 20-80 years of age, were recruited, chronologically, for this study. Subjects treated for high blood pressure were not included. Their autonomic function was assessed by the total score of five classical cardiovascular function tests. In the same subjects and in 44 healthy subjects, blood pressure and HR were determined from beat to beat by the Finapres system with subjects in the sitting position. We examined the randomness of the HR changes by calculating the zeta statistic of the runs test on 1,000 successive HR readings (the zeta value is low if the HR changes are random). When the HR changes are random, we consider that the autonomic control of HR is impaired.

RESULTS

The zeta values of HR changes were significantly lower in diabetic subjects compared with normal subjects (2.98 +/- 0.97 vs. 3.54 +/- 0.97, P < 0.004). In diabetic subjects, the zeta value was closely correlated to the total score of disautonomy (r = -0.66, P < 0.0001, after correction for age effect) and to the office systolic blood pressure (r = -0.43, P < 0.001).

CONCLUSIONS

The zeta value of HR changes might be a marker of the autonomic function in diabetic subjects.

[Cardiovascular autonomic neuropathy and blood pressure variability in insulin-dependent diabetes]

The aim of this study was to analyse the role of cardiac autonomic neuropathy (CAN) in the changes of Blood-Pressure (BP) variability among insulin-dependent diabetics and to determine the relationship between BP variability and diabetic complications. Ambulatory BP monitoring was performed during 24 hours on 93 insulin-dependent diabetics and 77 normal subjects of similar age (Group 1). CAN was assessed by the cardiovascular autonomic function tests described by Ewing and the diabetics were divided in two groups: Group 2 including patients without CAN (n = 46) and Group 3 including patients with CAN (n = 47). The 24 h standard deviation (variability) and the day/night difference for systolic and diastolic BP were calculated for each subjects. Systolic and diastolic BP variability is more elevated in Group 3 than in the other groups during the diurnal period. Furthermore, the day/night difference of systolic and diastolic BP is lower in Group 3 compared to groups 2 and 3. Diabetic complications are also more frequently observed among diabetic patients with CAN (p < 0.001). So CAN seems to have two types of consequences on BP curve among diabetic patients: a decrease of day/night BP difference which can be responsible of relative hypertension during the night and an increase of BP variability. As frequency of diabetic retinopathy and nephropathy is more elevated among diabetic patients with CAN, it is possible that CAN plays a role in the occurrence of these complications. Therefore, a simple juxtaposition of these facts is also possible.

[Comparative evaluation of diabetic cardiac autonomic neuropathy by spectrum analysis and Ewing's tests]

METHODS

62 diabetic patients of both sex (age: 46 +/- 16 yr, BMI: 26.1 +/- 4 kg/m2, casual blood pressure: 134 +/- 17/81 +/- 11 mmHg, mean age of diabetes: 11 +/- 9 yr) without cardiovascular medications were recruited. Autonomic involvement was based on the results from a battery of five cardiovascular tests as suggested by Ewing. The result of each test and a scoring system was considered. All patients underwent power spectral analysis (PSA) of digital blood pressure (BP) and RR intervals recorded in the recumbent position and after tilting with a Finapres monitor. The percentage of total power (0.025-0.4 Hz) computed in the low-frequency band (0.070-0.139 Hz) computed in the low-frequency band (0.070-0.139 Hz) was chosen as a sympathetic index (sigma Ind). Results of tests were correlated with sigma Ind.

RESULTS

24 patients (39%) have an autonomic involvement. The most affected tests are: the Valsalva maneuver (VAL): 16% RR response from lying to standing (LS): 25%, sustained handgrip (SHG): 30%, postural hypotension (PH); 57%, deep breathing (DB): 87%. Correlations coefficients of cardiovascular tests and sigma Ind are: VAL/sigma Ind (SBP tilt): r = 0.277, p = 0.029; Val/sigma Ind (DBP tilt): r = 0.318, p = 0.012; VAL/sigma Ind (RR tilt): ns. PH/Ind sigma (SBP tilt): r = 0.391, p = 0.0017; PH/sigma Ind (DBP tilt): r = -0.296, p = 0.019; PH/sigma Ind (RR tilt): r = -0.308, p = 0.015, DB/sigma Ind (SBP tilt): r = 0.417, p = 0.0007; DB/sigma Ind (DBP tilt): r = 0.361, p = 0.0039; DB/sigma Ind (RR tilt): ns. Results of LS and SHG show no correlation with Ind sigma. Correlations between global autonomic score (GAS) and sigma Ind during tilting have the following values: GAS/sigma Ind (SBP tilt): r = -0486, p = 0.0001; GAS/sigma Ind (DBP tilt): r = -0.385, p = 0.002; GAS/sigma Ind (RR tilt): r = -0.411, p = 0.0009.

CONCLUSIONS

The so-called sympathetic index computed from PSA are well correlated with autonomic tests. They allow an early detection of sympathetic involvement in diabetics patients. These results are to consider while managing these subjects.

Fractal dimension of heart rate and blood pressure in healthy subjects and in diabetic subjects

Beat-to-beat heart rate (HR) and blood pressure (BP) were measured by the Finapres system in 28 healthy subjects and 64 diabetic subjects. Autonomic controls in diabetic subjects were assessed by scoring 5 cardiovascular function tests (high score = abnormal control). The fractal dimension (FD) of HR (or SBP) was estimated as follows: Measuring the curve of 500 successive HRs with a rule of length L, one obtains N times L. The FD is the slope of the regression line of Log(N) versus Log(1/L) for different L. We found a lower FD of HR in diabetic subjects than in healthy subjects (1.35 +/- 0.10/1.44 +/- 0.09, p = 0.0002) and a similar FD of SBP in the 2 groups. In diabetic subjects, the FD of HR was negatively correlated with age (r = -0.27, p = 0.03), duration of diabetes (r = -0.33, p = 0.0078) and score of disautonomy (r = -0.43, p = 0.0007). So, heartbeat is more fractal in healthy status: a low fractal fluctuation is a sign of pathology.

Relationship between autonomic dysfunction and BP variability in subjects with diabetes mellitus

Autonomic vagal heart rate (HR) control, office BP and ambulatory BP were examined in 54 diabetic subjects, aged 63 +/- 6 years. Sixteen subjects were insulin-dependent. The HR response to deep breathing (the bradypnoea test) was used to evaluate the vagal HR control, and ambulatory BP was determined by the Spacelabs 5200 system (one determination every 15 minutes, for 24 hours). Twenty-seven subjects had normal office BP (SBP < or = 140 mmHg and DBP < or = 90 mmHg), seven had established hypertension (SBP > or = 160 mmHg and DBP > or = 95 mmHg) and 30 were borderline hypertensives. Over the total group, office systolic/diastolic BP (mean +/- SD) was 142 +/- 20/85 +/- 10 mmg. Systolic/diastolic ambulatory BP was 123 +/- 13/77 +/- 10 mmHg and ambulatory HR was 70 +/- 8 beats/min. Because of the small age range of our subjects, the HR score was not correlated with age (r = 0.19, NS). The HR score was not correlated with the levels of office and ambulatory pressures. In contrast, it was significantly correlated with the variability of ambulatory SBP, whether the variability was defined by the pressure standard deviation, or by the ratio SD/mean value (r = 0.40, P = 0.005 and r = 0.33, P < 0.017, respectively). We suggest that an impairment of the autonomic control in diabetics might induce an increase in variability of SBP. BP variability might play a role in the cardiovascular complications observed in diabetics.

[Early spinal bone loss in Klinefelter syndrome. X-ray computed tomographic evaluation in 16 cases]

The lumbar spine bone density (BMD) was assessed by single energy quantitative tomography in 16 young patients with non traited Klinefelter's syndrome (19 +/- 2.2 yr) and in 16 age weight- and height-matched control males. The BMD were significantly lower in the patients than in the control group (175 +/- 26 mg/cm3 K2HPO4 vs 204 +/- 26; p < 0.02). The authors found a significant correlation between BMD and plasmatic levels of testosterone and estradiol suggesting the hormonal origin of the osteopenia whereas no correlation was found with serum calcium, phosphorus or prolactin levels or hydroxy-proteinuria. Such osteopenia in young patients with Klinefelter's syndrome supports early androgenic treatment of these patients.

Active ambulatory blood pressures and urinary electrolytes in young male subjects with normal blood pressure or borderline hypertension

OBJECTIVES

To examine the relationship between ambulatory blood pressure (ABP) and 24-h urinary electrolytes in young subjects with normal blood pressure or borderline hypertension.

DESIGN

ABP shows a circadian profile. We question whether high- and low-level pressure spans might have a relationship with urinary salt output.

METHODS

ABP was monitored by the SpaceLabs 5200 system in 182 young male subjects (aged 17-25 years) with normal or borderline office blood pressure. In all subjects, 24-h urinary sodium, potassium and chloride were measured. The mean values and SD of ABP during 24 h, or during the daytime (0900-2100 h) and night-time (2115-0845 h), were estimated. In addition, using a 'cumulative sum' method, 'active' (high-level) and 'passive' (low-level) spans of APB were identified in each subject.

RESULTS

No relationship was found between 24-h urinary sodium, potassium or chloride and office systolic blood pressure. Also, no relationship was found between the electrolytes and mean value or SD of ABP during 24 h, daytime or night-time. In contrast, significant positive correlations were found between 24-h urinary sodium and active systolic and diastolic blood pressure. The present study suggests that the active blood pressure span is associated with salt intake in normal and borderline blood pressure groups.

[Chaotic aspect of heart rate and blood pressure in diabetic patients]

We applied a simplified version of the method suggested by Sugihara-May (Nature 1990: 344: 734-41) to study the control of heart rate (HR) in subjects with diabetes mellitus. The method aims to predict the future of an observation, if a series of observations on the same phenomenon is available. The method quantifies the fact that the series is predictable more or less longtime in the future. A random series is only shortly predictable in the future. HR and blood pressure were measured from beat to beat (by the Finapres system) for about 0.5 hours in 11 subjects with diabetes mellitus and normal blood pressure (group D) and in 10 controls subjects (group N). The subjects were sitting in a temperature-controlled quiet room, isolated from all external stimuli. The 2 groups were matched for age, and had the same weight and height. No difference was observed in mean-value and standard deviation (SD) of BP and HR between the 2 groups. Groups N/D: SBP = 112 +/- 11/123 +/- 11 mmHg, NS; DBP = 64 +/- 9/67 +/- 12 mmHg, NS; HR = 70 +/- 10/69 +/- 7 b/min, NS. Standard deviation of PAS = 5.5 +/- 1.6/5.7 +/- 1.9 mmHg, NS and SD of DBP = 3.5 +/- 0.9/3.4 +/- 1.2 mmHg, NS. The SD of HR (3.0 +/- 0.5/2.3 +/- 1.0 b/min in groups N/D) was somewhat lower in diabetics than in control subjects but the difference was not significant.(ABSTRACT TRUNCATED AT 250 WORDS)

Ambulatory blood pressure is still elevated in treated hypertensive diabetic subjects compared with untreated diabetic subjects with the same office blood pressure

Ambulatory blood pressure, ABP, was determined every 15 min for 24 h (Spacelabs 5200 system) in 16 hypertensive diabetic subjects treated for high blood pressure. Office blood pressure (OBP) in these subjects (systolic BP greater than 160 mmHg and diastolic BP greater than 95 mmHg before treatment) had been reduced by treatment to the borderline range (systolic less than or equal to 160 mmHg and/or diastolic less than or equal to 95 mmHg). Sixty-five diabetic subjects with normal or borderline OBP were included as controls. The two groups had the same age (58 +/- 10 yrs in both groups), duration of diabetes (15 +/- 9 yrs), 24 hr microalbumin, and included the same percentage of subjects with moderate neuropathy (36% and 29%, NS). The two groups had the same OBP (138 +/- 16 mmHg and 140 +/- 16 mmHg systolic, NS, 84 +/- 9 mmHg and 84 +/- 13 mmHg diastolic, NS). In contrast, ambulatory BP was significantly higher in the treated group, when compared with the controls (123 +/- 13 mmHg and 133 +/- 23 mmHg systolic, P less than 0.025, 77 +/- 7 mmHg and 84 +/- 16 mmHg diastolic, P less than 0.015). The difference was significant both in daytime and in nighttime, and was more significant in nighttime (11 mmHg systolic, P less than 0.02, 9 mmHg diastolic, P less than 0.004) than in daytime (9 mmHg systolic, P less than 0.05 and 5 mmHg diastolic, P less than 0.05). Ambulatory heart rate was also significantly higher in the treated group, but only in daytime (7 b/min difference, P less than 0.02). The study demonstrated the need to survey and investigate ABP in treated hypertensive diabetic subjects.

[Bone density in differentiated cancer of the thyroid gland treated by hormone-suppressive therapy. Study based on 51 cases]

The effect of L-Thyroxine suppressive therapy (207.3 +/- 46.1 mcg/d) on lumbar spine bone density (BMD) was assessed in 51 patients thyroidectomized for carcinoma since 1 to 19 years (mean = 6 +/- 5.4 years); the bone densities of these patients were compared with those of 51 age sex weight-matched control subjects. Trabecular bone density was evaluated by single energy quantitative tomography. The vertebral BMD was not significantly different between the patients receiving suppressive doses of L-T4 and the control group (162.8 +/- 40.4 vs 162.7 +/- 39.8 mg/cm3). We found no relationship between the duration of L-Thyroxine therapy and BMD. Thus, doses of L-T4 sufficient for suppressing plasma thyroid stimulating hormone but no high enough for causing biochemical thyrotoxicosis have no harmful effect on trabecular bone mineral density.

The tropospheric abundances of NH3 and PH3 in Jupiter's Great Red Spot, from Voyager IRIS observations

To investigate the chemistry and dynamics of Jupiter's Great Red Spot (GRS), the tropospheric abundances of NH3 and PH3 in the GRS are determined and compared to those of the surrounding region, the South Tropical Zone (STZ). These gases well up from deep in the atmosphere, and, in the upper troposphere, are depleted by condensation (in the case of NH3), chemical reactions, and UV photolysis. At Jupiter's tropopause, the chemical lifetimes of NH3 and PH3 are comparable to the time constant for vertical transport over the atmospheric scale height. The distributions of these gases are therefore diagnostic of the rate of vertical transport in the upper troposphere and lower stratosphere. Three groups of Voyager IRIS spectra are analyzed, two of the STZ and one of the GRS. The two groups of STZ spectra are defined on the basis of their radiances at 602 and 226 cm-1, which reflect, respectively, the temperature near 150 mbar and the cloud opacity in the 300-600 mbar region. One selection of STZ spectra is chosen to have the same radiance as does the GRS at 226 cm-1. The other STZ selection has a significantly greater radiance, indicative of reduced cloudiness. Variations in the abundances of NH3 and PH3 are determined within the STZ, as a background for our studies of the GRS. Within the uncertainty of our measurements (-55% and +75%), the PH3 mixing ratio at 600 mbar is 3 x 10(-7), the same for all three selections. The NH3 mixing ratio profile in the pressure region between 300 and 600 mbar is the same within error (-25% and +50% at 300 mbar) for both STZ selections. In the GRS, however, NH3 is significantly depleted at 300 mbar, with an abundance of 25% that derived for the STZ selections. Since the GRS is believed to be a region of strong vertical transport, our finding of a depletion of NH3 below the tropopause within the GRS is particularly unexpected. One of the STZ selections has a temperature-pressure profile similar to that of the GRS below the 300-mbar level; therefore, condensation at this level does not easily explain the low NH3 abundance in the GRS. All samples are taken at essentially the same latitude; photolysis and/or charged particle precipitation is probably not directly responsible either. The observed NH3 depletion may have a dynamical origin or result from some unidentified chemical processes at work in the GRS.

[Role of nocturnal hypertension in the deterioration of diabetic nephropathy]

Nocturnal hypertension (HTA), even a relative one, consequence of the change of the circadian pattern of blood pressure, may increase the whole day blood pressure in diabetic patients.

MATERIALS AND METHODS

blood pressure has been measured every 15 minutes for 24 hours in 101 diabetic patients (43 insulin-dependent: type 1, 58 non insulin-dependent: type 2) by ambulatory blood pressure monitoring. 39 of them are hypertensive patients. Among these 101 patients, 19 have a nocturnal relative HTA corresponding in a lack or a negative difference between the diurn and the nocturn systolic or diastolic pressure (Group 1). The Group 2 is constituted by the 82 other patients; 24 hour-microalbuminuria was assayed by immunoturbidimetry for two days on end.

RESULTS

patients of Group 1 were significantly older (p less than 0.01) than in the Group 2 (61 +/- 9 years vs 54 +/- 13 years). There was no significant change between the two Groups concerning the kind of diabetes (type 1 or type 2), the glycosylated hemoglobin and the frequency of degenerative complications. Microalbuminuria was significantly higher (p less than 0.01) in Group 1 (72 +/- 104 mg/24 h) than in Group 2 (20 +/- 30 mg/24 h). Both nervous dysautonomic cardiac failure and HTA treated were significantly higher in Group 1 than in Group 2, respectively (14/19 vs 28/82; p less than 0.01) and (15/19 vs 24/82; p less than 0.001). The causal blood pressure measurement was similar in the two Groups, but the whole day ambulatory blood pressure monitoring revealed a significant increase of the average of systolic (Group 1: 133 +/- 14 mmHg vs Group 2: 119 +/- 12 mmHg; p less than 0.001) and diastolic (Group 1: 81 +/- 12 mmHg vs Group 2: 75 +/- 8 mmHg; p less than 0.01) blood pressure during 24 hours.

COMMENTS

the causal blood pressure measurement fails to appreciate the increase of the whole day blood pressure consequent to the suppression of nocturnal hypotension and sometimes to the occurrence of real nocturnal hypertension. This observation is probably in relation with the nervous dysautonomic cardiac failure and is associated with an increase of the microalbuminuria (patients with microalbuminuria greater than 30 mg/24 h--Group 1: 9/19 vs Group 2: 17/82; p less than 0.05). This situation can lead to an aggravation of degenerative complications. Such results should urge practitioners to assess the circadian pattern of blood pressure in diabetic patients more accurately.