Quantitative studies on liver fibrosis and alpha-smooth muscle actin expression in heroin abusers

Lobular hepatic fibrosis and the presence of myofibroblasts were studied in heroin abusers, by quantitative automatic image analysis. Nineteen addicts (DA) and thirteen patients having stopped consumption (exDA) were compared to a non-addict group (CONTROL). Addicts, all anti-HIV and HBsAg negative, showed increased transaminase levels. Hepatitis C markers were ot available, at the time of biopsy. The surface of the centrolobular fibrosis, measured on picrosirius stained slides, was respectively 1.9 and 3.5 times larger in DA and exDA than in CONTROL (p < 0.0001). Immunolabelling with an alpha-smooth muscle actin antibody (alpha-SMA) revealed stellate cells in a perisinusoidal location, mainly in areas of matrix thickening in the space of Disse. Morphometric analysis of alpha-SMA expression showed significant differences between the three groups of patients, p < 0.0001 (CONTROL: 198.06 +/- 5.59 microns2; DA: 2227.91 +/- 88.02 microns2; exDA: 3469.10 +/- 154.98 microns2). The surface density of collagen and of alpha-SMA reactivity was also significantly different between these groups (p < 0.0001). These data strongly suggest that heroin is responsible for an early and progressive centrolobular liver fibrosis, occurring simultaneously with a myofibroblastic response. It might represent a reparative phenomenon arising from a direct vascular injury, leading to an impairment of blood-hepatocyte exchange.

Pathogenic role of gastric Helicobacter sp in domestic carnivores

As a result of phylogenic studies using new molecular biology techniques and fundamental experimental studies, we now know more about helicobacteria in domestic carnivores, their morphologic characteristics, their taxonomia and more important we know more about their ecological niche. Few clinical studies have been carried out, but the ones that have been undertaken are interesting in that they confirm the extensive prevalence of Helicobacter infections in domestic carnivores and underline their role in the genesis of the inflammatory gastropathies observed in these species. Finally, recent observations have demonstrated the ubiquitous character of these helicobacteria by showing their presence in the stomach of man, dog and cat. This ubiquitous character has led some scientists to consider the potential zoonotic risk of the human infection by Helicobacter heilmannii, felis or pylori.

The isolated perfused porcine liver: assessment of viability during and after six hours of perfusion

Isolated liver perfusion was developed for the study of liver physiology and preservation. The recent development of new perfusion devices and appropriate liver preservation solutions prompted us to reconsider liver perfusion for the specific purpose of evaluating viability in terms of biochemical changes, paying special attention to modifications in the histological ultrastructure. Twenty-two isolated pig livers were perfused with autologous blood. Arterio-portal perfusions were carried out using an extracorporeal perfusion circuit with a hollow fibre membrane oxygenator. Four groups of pig livers were studied using three different liver flushing solutions [Ringer's lactate, ELOHES, and University of Wisconsin (UW)] and two different oxygenation modalities. Liver function tests and histological studies were done. Our results revealed that a high partial oxygen pressure (PO2) level was deleterious to the ultrastructural elements of hepatocytes, in particular to the mitochondria. It was also associated with deficient metabolic performance, i.e., poor bile production and lack of aerobic metabolism. Normal blood gas values could be obtained with the use of air for liver oxygenation. Flushing of the liver with Ringer's lactate or a macromolecular solution such as ELOHES was associated with severe liver cell injuries, as reflected by a marked rise in liver enzymes and histological lesions. Satisfactory results were obtained when UW solution was used for liver harvesting. We conclude that an appropriate liver preservation solution, normal blood gas values, and normal physiological arterio-portal pressure and blood flow are essential for appropriate liver function with preservation of liver architecture and of hepatocyte ultrastructures. Total bilirubin in bile and Factor V are sensitive indicators of good liver function.

[Diagnostic value of renal scintigraphy with MAG 3 and DTPA in the diagnosis of renal artery stenosis]

Angiography still remains the first line investigation to demonstrate a renal artery stenosis. We have evaluated the sensitivity and the specificity of renal scintigraphy in the diagnosis of renal artery stenosis using two technetium markers, MAG 3 and DTPA.

PATIENTS

45 hypertensive (HT) patients (WHO criteria) referred for investigation of renovascular hypertension according to the criteria of the AHA Scientific Council and were found to have a unilateral renal artery stenosis of varying severity. Age was 61 > +/- 13 years; sex-ratio F/M 21/24; creatinine < 150 mumol/l. There were non insulin dependent diabetics, and none had been treated with ACE inhibitors or diuretics for 15 days. Bilateral arterial stenosis was excluded a posteriori.

METHODS

MAG3 and DTPA scintigraphy were performed one hour after a dose of 25 mg of captopril plus hydration with 500 ml of intravenous saline. Blood pressure was measured by dynamap every 15 min from minus one hour to the end of the study. The principle outcome measure was nephorgram phase and the secondary measure was the angiographic phase (two images per second). The two scintigraphy techniques were performed at a mean interval of 2.9 +/- 2.1 days. Digitized angiography via the arterial route was performed using left anterior oblique and right anterior oblique images.

RESULTS

[table: see text]

CONCLUSION

There was only one false positive scintigraphy result with a polar artery. In contrast 45% of unilateral stenoses were not diagnosed by scintigraphy. Both markers gave similar results even if subjectively the MAG3 images were of better quality. Analysis of the angiographic phase and of the size of the kidneys did not improve the diagnostic accuracy and could lead to false positive results.

The carboxy-terminal cross-linked telopeptide of type I collagen (ICTP) is a potential serum marker of ongoing liver fibrosis

We report for the first time the measurement of the serum concentration of the carboxy-terminal cross-linked telopeptide of type I collagen in patients with various liver diseases. This breakdown product of type I collagen, which is the major collagen type found in fibrotic liver, was measured by a radioimmunoassay in the serum of 149 patients with various liver diseases and in 67 controls. Its concentration is significantly elevated (P < 0.05) above reference intervals in sera from patients with liver diseases, except in patients with chronic active hepatitis of unknown origin and in patients with acute hepatitis A. In the 143 patients with liver fibrosis, the serum level of the carboxy-terminal telopeptide of type I collagen is correlated with the extent of fibrosis, as assessed by a histological scoring system (r = 0.3899, P < 0.0001), but not with inflammation and necrosis.

In situ detection of human cytomegalovirus DNA in gastrointestinal biopsies from AIDS patients by means of various PCR-derived methods

The development of new in situ assessment of HCMV disease on endoscopical gastrointestinal biopsies from AIDS patients is described and compared with the viral load measured by semiquantitative solution-phase PCR (SQ-PCR). Ten biopsies were examined by viral isolation, standard histology, in situ hybridization (ISH), in situ PCR-hybridization (PCR-ISH) and SQ-PCR, using the same target sequence. The methods developed for in situ HCMV detection were HCMV primers, the plasmid pCMV 406-S, a vector-free-digoxigenin-labelled HCMV-362 probe and the pSK + MCS nonsense probe. Paraffin-embedded MRC5 cells, either HCMV-infected or uninfected served as controls of specificity for ISH. beta-Actin primers were designed as markers of DNA integrity. Computerized models of the PCR, solution-phase and in situ PCR on formalin-fixed DNA indicated that HCMV and beta-actin primers were efficient and specific. Nine biopsies were negative for HCMV by histology and virus isolation. SQ-PCR revealed 80,000; 80 and < 80 HCMV genomic equivalents in 6, 2 and 2 biopsies, respectively. In 8 biopsies, both ISH and PCR-ISH identified positive nuclei in the intestinal epithelium, with sparing of the lamina propria. This indicates that an improvement in in situ methods can help the timely diagnosis of HCMV infection. Direct in situ PCR with beta-actin primers showed a positive signal in all the nuclei in the tissue sections, whereas omission of Taq polymerase resulted in an absence of signal, implying optimal in situ PCR. The data suggest an early-stage reactivation of HCMV, possibly harboured in the intestinal epithelium.

[Histopathology of viral hepatitis C]

In patients with C virus, liver biopsy is an essential examination for diagnosis of chronic hepatitis. This examination evaluates the two basic lesions of the disease: aggressivity and fibrosis. During antiviral treatment, only liver biopsy is able to give precise details about liver lesions and no reliable serum test is yet available for the follow-up. Molecular biology methods applied to liver sections for viral genome detection will be of great interest for follow up and pathophysiology of the chronic disease. These sensitive techniques will supply absence of any pathognomonic histological feature associated with C virus in liver tissue.

[Baroreflex sensitivity and vascular involvement in hypertension]

Relationships between baroreflex sensitivity (BRS) and arterial distensibility are evaluated by continuous measurement of blood pressure (Finapres) and carotid-femoral pulse wave velocity measurement (PWV); 73 subjects are recruited on WHO criteria (age: 48 +/- 13). An ambulatory measurement of BP is also performed to evaluate the mean BP 24 level. The BRS is evaluated at rest during 20 min of acquisition data in a lying position, using a dedicated software [(automatic detection by of BP sequences were 3 or more systolic BP and RR interval increased of 1 mmHg for SBP and 4 ms for RR (PS+/RR+) or decreased (PS-/RR-)]. The BRS is the slope of the regression line between SBP and RR interval of each sequences (if correlation coefficient > 0.95).

RESULTS

resting BP: SBP/DBP = 170 +/- 12 mmHg. HR 72 +/- 15 batt/min, PWV = 10.8 +/- 3.2 m/s. Mean BRS is 8.2 +/- 3.8 for PS+/RR+ and 8.7 +/- 3.8 ms/mmHg PS-/RR-. The coefficient of correlation (Pearson) between PWV and BRS is -0.59* for PS+/RR+ and -0.41* for PS-/RR- (*: p < 0.01). In multivariate analyses, these relations were statistically independent of age and BP for the sequences PS+/RR+ but not for the sequences PS-/RR- suggesting a predominant vagal alteration in hypertensive subjects associated with the alteration of carotido-femoral pulse wave velocity.

[Reproducibility of echocardiographic parameters by automatic detection of contours in hypertensive patients]

The reproducibility of automatic outline detection is a echocardiographic reproducibility which has been poorly evaluated in patients with cardiomyopathy. Two independent observers identified the systolic surface and mid and end diastolic surfaces of 27 hypertensive patients, who had been referred to the laboratory for the measurement of left ventricular mass. Each observer examined on two occasions all parameters and all parameters were measured at least 2 hours apart. The coefficient of variation (CV) expresses the reproducibility of each measurement. The intra observer was 10 to 15% and the inter observer 15 to 22% for the measurement of surface area. The coefficient of variation is regularly greater than 20% for measures of maximum speed, which characterise surface changes in diastole. The automatic detection of contours is a echocardiographic tool whose potential is great for evaluating left ventricular function but the current versions can only be applied to very selective group of patients depending on the quality of their echographic window for acoustic quantitation. This technique is very operator dependent, in particular as regards setting the gains and this explains its poor reproducibility and its limited interest in daily clinical practice.

[Paradoxic changes in the morphology of blood pressure wave in hypertensive heart diseases]

The objective is to study the relation between left ventricular (LV) effect (index of LV mass (LVMI) and index of inotropic state) and arterial compliance determined but the proximal aortic pressure waveform and by the carotid femoral pulse wave velocity.

MATERIAL

72 untreated hypertensives; systolic blood pressure (SBP) 170 +/- 18 mmHg/diastolic blood pressure (DBP); heart rate: 69 +/- 9 batt/min; age: 48 +/- 13 years; duration of hypertension 4.6 +/- 4.8 years; sex ratio 49 M/23 F.

OBJECTIVE

Proximal aortic pressure waveform (carotid artery) was studied by applanation tonometry. We derived the index of amplification (AI = Pmax-Pinflex)/PP, %), pulse pressure (PP), the maximum rate of rise of pressure (dpdt, mmHg.s-1). Echocardiography was used to define the index of LV mass (VLMI), end systolic volume (ESV), end systolic stress (ESS), myocardial contractile force (ESS/ESV), inotropic state (SBP/ESV). Carotid-femoral pulse wave velocity was determined by mechanogram (PWW m/s).

RESULTS

1. Relationship of physiological changes of AI and SDA to age, height, PP, DBP, PWV, and LVMI were observed in table I (r-Pearson cor. coefficient, * < p 0.05; **: p < 0.001). [table: see text] In stepwise regression analysis, even allowing for BP, age, and height, there was no relationship between LVMI and the index of aortic amplification (AI). 2. In the subjects with LVH (LVMI > 110 g/m2) we found a bimodal distribution of the AI which defines two groups in agreement with the Murgo Classification. [table: see text] In type B, where AI is weaker, the indices of aortic rigidity are reduced, there is an increased ESS and a paradoxal fall in LV performances.

CONCLUSION

Analysis of proximal aortic pressure waveform don't allow to predict index of LV mass. These results suggest that in the sphere of LV aortic compiling the reduction of LV function contributes to modification of the BP waveform with diminution of dpdt and the index of amplification.

A comparison of three interferon alfa-2b regimens for the long-term treatment of chronic non-A, non-B hepatitis. Multicenter Study Group

BACKGROUND

We studied the effects of long-term treatment with interferon on histologic features of the liver and serum alanine aminotransferase concentrations in patients with chronic non-A, non-B hepatitis.

METHODS

Consecutive patients who met the inclusion criteria were enrolled in the study. The diagnosis of chronic non-A, non-B hepatitis was established on the basis of the liver-biopsy findings and an abnormal serum alanine aminotransferase value (greater than 1.5 times the normal value) for at least one year. All patients were treated for six months with 3 million units of interferon alfa-2b given subcutaneously three times a week and were then randomly assigned to the same treatment for an additional 12 months (group 1), a regimen of 1 million units three times a week for 12 months (group 2), or no further treatment (group 3). Patients in group 3 who had elevated serum alanine aminotransferase concentrations for three consecutive months underwent the initial regimen once again. Follow-up continued for two years after the discontinuation of treatment. Histologic improvement was defined as a decrease of at least one grade in the score for necroinflammatory activity (0, no activity; 1, mild; 2, moderate; or 3, severe) between the first liver biopsy and a biopsy performed at 18 months.

RESULTS

Of the 329 patients initially treated, 303 were randomized: 103 to group 1, 101 to group 2, and 99 to group 3. Of the 286 patients tested, 252 (88.1 percent) had antibodies to hepatitis C virus. In an intention-to-treat analysis, 46 of the patients in group 1 (44.7 percent) had normal serum alanine aminotransferase values at 18 months, as compared with 27 of the patients in group 2 (26.7 percent, P = 0.008) and 30 of those in group 3 (30.3 percent, P = 0.04). Between 19 and 42 months, 23 of the patients in group 1 (22.3 percent) continued to have normal serum alanine aminotransferase values (measured every six months), as compared with 10 of the patients in group 2 (9.9 percent, P = 0.02) and 8 of those in group 3 (8.1 percent, P = 0.005). Among the 176 patients with repeated liver biopsies at 18 months, more patients in group 1 had improved histologic-activity scores (69.6 percent) than in group 2 (47.6 percent, P = 0.02) or group 3 (38.6 percent, P < 0.001).

CONCLUSIONS

Among patients with chronic non-A, non-B hepatitis, a regimen of 3 million units of interferon alfa-2b given three times a week for 18 months produced better histologic findings and serum alanine aminotransferase values than regimens involving a lower dose or a shorter duration of treatment.

Monitoring levels of human cytomegalovirus DNA in blood after liver transplantation

We evaluated a semiquantitative PCR assay prospectively in 40 liver transplant recipients as an aid in making a prompt diagnosis of cytomegalovirus (CMV) infection. For 2 months after transplantation, clinical specimens from patients were tested weekly by PCR, virus isolation from peripheral blood and urine, and CMV serology. The incidence of active CMV infection was 70%. The levels of CMV DNA determined by hybridization of PCR samples and densitometric scanning of blots were assigned a score of 1 to 4 by comparison with four external standards amplified in parallel and corresponding to a range of 80 to 80,000 genomes. The first detection of CMV in blood by PCR occurred at a mean of 15 days, and high-level PCR scores of 3 or 4 were obtained 21 days after transplantation, whereas viremia occurred 33 days after transplantation. Significantly higher levels of CMV DNA were seen in patients with CMV disease (P < 0.05) than in asymptomatic patients. The prevalence of symptomatic CMV infection was 30%. The positive predictive value of PCR was 48%, while the negative predictive value was 100%. After treatment, the clearance of CMV DNA was always observed and the disappearance of symptoms occurred concomitantly with undetectable PCR signals.

Co-infection by hepatitis B virus and hepatitis C virus in renal transplantation: morbidity and mortality in 1098 patients

The aim of the study was to analyse the influence of co-infection by hepatitis B virus (HBV) and hepatitis C virus (HCV) as compared with HCV infection alone in 1098 patients who received a kidney transplant between 1 January and 31 December 1991. At transplantation, the prevalence of anti-HCV antibodies was 21.40% (235/1098) while the prevalence of HBV infection was 9.85% (108/1096); 46 patients were co-infected with HBV and HCV, either 19.70% of HCV-infected patients and 42.60% of HBV-infected patients. Liver tests, galactose clearance and liver biopsy were compared in the 46 co-infected patients (HCV+HBV+) and in the 189 HCV-infected patients (HCV+HBV-). At the time of transplantation, cytolysis was present in 31.45% of HCV+HBV- patients (50/159) and in 40% of HCV+HBV- patients (16/40); cholestasis was present in 34.18% of HCV+HBV- patients (34/158) and 42.11% of HCV+HBV+ patients (16/38). At 6 months the incidence of biological abnormalities increased to 37% in HCV+HBV- patients (55/150) and to 52.5% in HCV+HBV+ patients (21/40), suggesting a more deleterious effect of the immunosuppressive therapy in the co-infected group. Over the course of transplantation, chronic hepatitis was present in 50% of HCV+HBV- patients and in 64.1% of HCV+HBV+ patients. Liver failure occurred in 7% of HCV+HBV- patients (12/156) and 17% of HCV+HBV+ patients (7/41). Galactose clearance was performed as a functional test in 68 patients: it was not significantly different in either group. Liver biopsy was performed in 108 patients at least once.(ABSTRACT TRUNCATED AT 250 WORDS)

Familial autoimmune enteropathy with circulating anti-bullous pemphigoid antibodies and chronic autoimmune hepatitis

In a family of four children (two boys and two girls), the two brothers had severe, protracted watery diarrhea beginning at 2 and 3 weeks of life, respectively. Duodenal mucosa in both patients showed total villous atrophy and severe inflammatory infiltration of the entire bowel. The first patient also had lymphoid cell infiltration of the pancreas and died at 6 weeks of age. The second boy is alive at 2 years of age and is immunocompetent, but still receives total parenteral nutrition. Indirect immunofluorescence studies revealed circulating antibodies to enterocytes, smooth muscle, thyroid, and islet cells. Bullous pemphigoid antibodies (230 and 180 kd), specific for hemidesmosomal proteins and usually associated with a subepidermal blistering skin disease, were detected by direct and indirect immunofluorescence studies and by Western immunoblot. A diagnosis of autoimmune hepatitis was made, based on evidence of chronic active hepatitis and circulating anti-smooth muscle antibody. Immunosuppressive treatments induced partial clinical remission of the diarrhea but no resolution of the small bowel injury. At 16 months of age, remission of the diarrhea occurred, but persistent autoimmune hepatitis led us to maintain treatment with prednisone and azathioprine, and later with cyclosporine. In this child, as in other patients with autoimmune disease, the link between autoantibodies and organ damage remains uncertain but immunosuppressive treatment is indicated.

[Changes in the morphology of the Doppler wave of the pulmonary venous blood flow in hypertensive heart diseases]

Analysis of pulmonary venous flow can contribute to understanding of ventricular diastole; 40 essential hypertensive subjects (HT) who had never been treated and 30 healthy normotensive subjects (NT) were studied by Doppler-echocardiography. All the subjects had normal systolic function on echocardiography. The analysis focussed on the velocity of transmitral flow as measured by pulsed Doppler, measuring E and A waves, and also on flow in the right superior pulmonary vein: S and D waves measured in the apical position. The D wave appeared to correlate with age (r = 0.62, p < 0.001), with systolic blood pressure (SBP) (r = -0.44, p < 0.05) a correlation which remained after adjustment for age, and for measures of diastolic function across the mitral valve: A wave, and to E wave in a less closely related fashion. The D wave was of a lower velocity with mitral Doppler type A than with normal mitral Doppler (46 +/- 9 vs 36 +/- 8 cm/s; p < 0.005). The S wave was weakly related to morphological measurements of LV such as end-diastolic diameter of LV(r = 0.3; p < 0.01). The Doppler of pulmonary venous flow may help in describing impairment in LV filling by giving complementary data on Doppler mitral flow. A type 1 mitral Doppler corresponds to a low amplitude D wave with the presence of elevation of LVEDP which limits LV filling. In difficult situations when E and A velocities are similar (normal or pseudonormal form) a weak velocity of D wave is in favour of type 1.

A histological semiquantitative scoring system for evaluation of hepatic fibrosis in needle liver biopsy specimens: comparison with morphometric studies

The evaluation of hepatic fibrosis on histological sections is of great interest for the staging and follow-up of chronic liver disease. Because no reliable scoring system is yet available, we have designed a semiquantitative scoring system in which the four main sites of fibrotic deposit--centrilobular vein, portal tract and perisinusoidal space, together with width and number of septa when present--are analyzed. These different items have been previously settled from comparison with morphometric measurements to evaluate surface density of total collagen performed on the same liver needle biopsy specimens stained with picro-sirius. The score has been tested on samples from 200 consecutive patients with various liver diseases and compared with the surface density of total collagen and Knodell scoring system. For observer variation study, the features by three independent pathologists were coded on 20 cases. There was a good interobserver (Kendall's tau-b = 0.75) and intraobserver (tau-B = 0.73) reproducibility. Each component of the fibrosis scoring system and total collagen surface density were significantly linearly related (one-way polynomial analysis, p < 10(-4); the correlation between semiquantitative scoring system and surface density of total collagen was 0.73 (p < 10(-5). Our semiquantitative scoring system, simple and reproducible, describes both liver architecture and fibrotic deposit. It is better related to morphometric measurement of fibrosis than each of its constituents or than the fibrosis item of the Knodell scoring system. It represents a reliable and convenient method for fibrosis evaluation, which is mandatory for clinical use.

Fulminant hepatitis with severe lactate acidosis in HIV-infected patients on didanosine therapy

We report two cases of fulminant hepatic failure in HIV-1-infected patients treated with didanosine (ddI). Clinical manifestations including vomiting, diarrhoea and dyspnoea were identical in both cases. Biological data mainly revealed hepatic failure and lactic acidosis. Histological examination of liver biopsies showed diffuse microvesicular steatosis. The outcome was fatal in both patients. The only comparable case previously reported (Lai et al., 1991) showed close similarities in the clinical, biological and histological manifestations with microvesicular steatosis. This prompted us to suspect that ddI might be responsible for fulminant hepatitis in all three AIDS patients. This toxic effect may be added to the list of potential adverse events occurring during ddI therapy.

Interferon-alpha 2b therapy reduces liver fibrosis in chronic non-A, non-B hepatitis: a quantitative histological evaluation

The aim of this study was to evaluate the effect of interferon-alpha on liver fibrosis with an established quantitative histochemical method for determining collagen as a marker. 59 patients (31 men, 28 women; 47 +/- 14 yr) with chronic non-A, non-B hepatitis (92% with hepatitis C virus antibody) received subcutaneous injections of 3 or 1 MU recombinant interferon-alpha 2b or placebo thrice weekly for 24 wk. Needle-biopsy sections taken before and after interferon treatment were examined for histological evaluation and collagen quantitation. Values were compared with results obtained by means of morphometrical analysis of liver collagen and Knodell scoring histological index. The index of periportal and/or bridging necrosis was the only component of Knodell's histological score significantly decreased (p < 0.05) in patients treated with 3 MU interferon compared with placebo-treated controls. The fibrosis score was not significantly changed. In contrast, liver total collagen variations measured colorimetrically and morphometrically were significantly decreased in patients treated with 3 MU and 1 MU compared with the increase observed in the placebo-treated controls (p < 0.05). From these results, we conclude that a 6-mo course of 3 MU or 1 MU interferon-alpha 2b causes slight but nonetheless significant regression of liver fibrosis as assessed on the basis of quantitative estimation of liver collagen, irrespective of other response criteria, whereas progression of liver fibrosis can be observed in the absence of treatment.

[Variation, variability of blood pressure. Study techniques]

Blood pressure (BP) is not a constant parameter, but exhibits variations, which involve a change in its value with time, and variability, which corresponds to the extent of this variation. A circadian pattern of BP, with higher values during the day than at night, is one expression of this variation in BP. This variation corresponding to the circadian pattern is dependent on both physical constraints and psychosensory factors. Investigation of variability implies consideration of both long-term and shorter term changes in BP. Long-term variability can be assessed by ambulatory determinations of BP, which can be carried out at intervals of 1/4 hour. This variability can be used to define the daytime/nighttime alteration of the circadian cycle, with the possible absence of the nocturnal reduction in BP or even a reversal of this circadian pattern. An abnormality of this type would be of prognostic importance, particularly in terms of impact on the left ventricle. Medium- or above all short-term variability can be assessed only from the change in beat/beat difference in BP and heart rate (HR) which depends on vagal tone and the orthosympathetic system. This variability can be detected by invasive methods and, more recently, using non-invasive methods (Finapres). It would seem that changes in this variability may reveal a defect in baroreceptor control which it is useful to identify for both diagnostic and therapeutic purposes.