[ETHICAL ASPECTS OF INFORMED CONSENT IN REFRACTIVE SURGERY]. / ASPECTS ÉTHIQUES DU CONSENTEMENT ECLAIRÉ EN CHIRURGIE RÉFRACTIVE.

With the introduction of the use of Laser assisted surgery, refractive eye surgery knows a very large success. Surgery of well being, it requires that an extensive information is delivered to the patient concerning the benefit and possible side-effects of the available treatments. This information process may reduce the frequency of negligence claims relating to Laser eye surgery.

[End of life care in the elderly]. / Gérer la fin de vie chez le sujet âgé.

The increase in life expectancy is associated with a good quality of life until a very old age. However, the unavoidable aging process eventually affects the autonomy of the patient and may force the individual to live in a nursing home. The alteration of sensorial functions and the increased number of degenerative diseases may finally induce a physical and psychological burden that might lead to resort to palliative care, end of life sedation, and in some cases, euthanasia.

[The medical decision for the non-competent patient]. / La décision médicale chez le patient incompétent: aspects légaux et ethiques.

The evolution of the therapeutic relation from a paternalistic to a collaborative one has increased the legal and ethical problems related to the medical care in non competent patients. The recent Belgian law on the rights of the patient (August 22, 2002 ) and the advice of the Belgian Council of the Medical Association on this matter provide the practitioner with clear directives. However, the responsibility of the final decision always remains in the hands of the medical doctor as the protector of the patient.

Isradipine in essential hypertension: the Belgian General Practitioners' Study.

Over 200 hypertensive patients were recruited by 37 general practitioners into a single-blind 12-week study to assess the efficacy, tolerability, and safety of isradipine as an antihypertensive, alone and in combination with guanfacine. A total of 212 patients were given isradipine at doses of 1.25 and 2.5 mg twice daily. Twelve hours after the last dose, diastolic blood pressure was reduced to no more than 90 mm Hg in 52.6 percent of patients treated with isradipine alone. After eight weeks of treatment, 30 percent of patients were also given guanfacine 1 mg daily. By Week 12, 67.6 percent of the patients had attained normotension. Compared with placebo, side-effect frequency was higher for flushing and edema with isradipine, and dry mouth was more frequent with added guanfacine. Electrocardiographic examinations and routine laboratory determinations showed no clinically relevant changes. These data indicate that isradipine as monotherapy and in combination with guanfacine is an effective antihypertensive agent. Most patients will continue to participate in a two-year follow-up involving bimonthly clinical visits and half-yearly electrocardiographic examinations and laboratory determinations.

Interrelationship of hypertension, plasma lipids and atherosclerosis.

The relationship between hypertension and atherosclerosis has been illustrated by epidemiological, clinical and experimental observations. Typical atherosclerotic lesions develop in arterial wall when hypercholesterolaemia is present. Hypertension aggravates these lesions by causing vascular structural changes. In clinical studies, however, the correction of high blood pressure does not decrease the incidence of coronary heart disease. Several hypotheses have been formulated to account for this observation: one is that reversibility of the structural vascular changes induced by hypertension is not complete when the blood pressure is lowered; another is that antihypertensive drugs have a deleterious effect on the vascular wall.

Low sodium diet in essential hypertension. Effect on blood cell ions and hemodynamic parameters.

The influence of salt restriction for 3 months on blood pressure, peripheral vascular resistance (observed by occlusive plethysmography), erythrocyte sodium, platelet calcium, and pH, was studied in eight untreated essential hypertensive patients. A low salt diet decreases blood pressure, vascular resistances, erythrocyte sodium, and platelet calcium, but not platelet pH. A strong positive correlation was noted between baseline platelet calcium and vascular resistances (r = 0.95, P less than .01). But during the salt restriction period, a negative correlation has been observed between the changes in these parameters, which casts doubt on the use of the platelet as a model of the smooth muscle cell.

Red blood cell Na-Li countertransport, hypertensive heredity, and cardiovascular risk in young adults.

The erythrocyte Na-Li countertransport (CT) has been considered as a marker of genetic propension to essential hypertension, but also to be linked to atherosclerosis risk factors. We have evaluated these relationships by measuring the Na-Li CT, blood pressure levels, the family predisposition to hypertension, body mass index, subscapular skin-fold thickness, waist/hip ratio, and plasma lipids in 43 young adults (22 to 23 years; 13 with a positive family history of hypertension), followed since adolescence (+/- 10 years) to analyze the natural history of blood pressure in this period of life. The Na-Li CT was negatively correlated with the HDL cholesterol (r = -0.37) and the HDL cholesterol/total cholesterol ratio (r = -0.44). This transport system was positively correlated to family history of hypertension (r = 0.38), waist/hip ratio, and the diastolic blood pressure. When the family history of hypertension was present, Na-Li CT and diastolic blood pressure were higher (P < .05), but the HDL cholesterol was lower (P < .01). After separating people according to the blood pressure level during adolescence in two groups, one lower than the 75th percentile (P75), and one higher, we notice that the latter remains characterized by a higher systolic blood pressure. But neither the Na-Li CT nor family history of hypertension and plasma lipids could explain the difference in the blood pressure behavior during this period. Thus, an increase of RBC Na-Li CT activity in young adults would suggest a higher cardiovascular risk rather than to be a simple marker of a hypertensive risk.

A double blind comparison of perindopril and atenolol in essential hypertension.

A multicentre randomised double-blind trial was performed in order to compare the therapeutic efficacy and acceptability of the angiotensin converting enzyme (ACE) inhibitor perindopril with those of atenolol in mild to moderate hypertension. After one month of placebo, 173 patients with supine diastolic blood pressure (DBP) between 95 and 125 mmHg were randomised to receive perindopril 4 mg once daily or atenolol 50 mg once daily. Monthly assessments were made for three months. Treatment was adjusted at these visits if supine DBP was greater than 90 mmHg; the dose was first doubled (8 mg perindopril or 100 mg atenolol once daily) and then hydrochlorothiazide was added. The pretreatment blood pressure levels were similar in both groups. Supine DBP was 105.5 +/- 0.9 mmHg (n = 85) in the perindopril group and 106.9 +/- 0.9 mmHg (n = 88) in the atenolol group. At the end of the third month, the study target blood pressure (supine DBP less than or equal to 90 mmHg) was achieved in a significantly (P = 0.006) larger percentage of patients in the perindopril group (78%) than in the atenolol group (58%). This appeared to be due to a greater potentiation of the antihypertensive effect by the addition of diuretic to perindopril than to atenolol. The fall in systolic blood pressure was significantly greater in the perindopril group than in the atenolol group (supine: 26.5 +/- 2.0 mmHg vs. 20.6 +/- 2.0 mmHg; P = 0.042) although the fall in DBP was comparable (supine: perindopril 17.4 +/- 0.9 mmHg, atenolol 15.6 +/- 1.1 mmHg; P = 0.195).(ABSTRACT TRUNCATED AT 250 WORDS)

Fracture and bone mineral density in hemodialysis patients.

AIM: The aim of this cross-sectional study was to determine in hemodialysis patients the pattern of low trauma fracture, the ability of dual X-ray absorptiometry (DXA) to discriminate between patients with and without fracture, and the magnitude, distribution and mechanism of bone loss. PATIENTS AND METHODS: Eighty-eight patients were studied. Bone mineral density (BMD) was measured by DXA at lumbar spine (LS), femoral neck (FN) and 3 radius sites (UD, MID and 1/3R). In 11 patients (12.5%), 16 fractures occurred and were predominant at the distal forearm and ribs. RESULTS: Patients with fracture had a significatively lower BMD Z-score at LS (-1.34 +/- 1.66 vs -0.42 +/- 1.23), at FN (-1.58 +/- 1.25 vs -0.60 +/- 1.01), at MID radius (-2.59 +/- 1.34 vs -0.93 +/- 1.76) and 1/3 radius (-1.62 +/- 1.60 vs -0.39 +/- 1.32). They also had a longer history of dialysis (113 +/- 64 vs 53 +/- 65 months). Prevalence of osteoporosis varied from 23% at LS to 50% at MID radius. CONCLUSION: Multiple regression analysis showed that there was no influence of gender, age, parathormone status and primary renal disease on BMD. However, at FN, UD, MID and 1/3 radius, a significantly negative correlation was found between length of dialysis and BMD Z-score. By contrast at LS, there was a positive correlation between age at onset of dialysis and BMD Z-score. Despite occurrence of fracture at the fistula forearm, BMD levels were similar in both arms.

A sulphonylthiourea (BM 20) related to torasemide: a new loop diuretic with relative potassium-sparing properties.

A series of sulphonylthioureas related to torasemide, a high ceiling loop diuretic, were synthesized and found to inhibit the Na+ 2Cl- K+ co-transporter of the thick ascending limb of the loop of Henlé. Their diuretic properties were studied (30 mg kg-1) after oral administration to rats. Lipophilic derivatives, very active in-vitro, were found inactive orally and intraperitoneally in rats. The four most active compounds were examined for their dose-dependent diuresis. Three of them showed a potency, water and electrolyte excretion similar to torasemide. The fourth molecule, a sulphonylthiourea (BM 20), exhibited relative potassium-sparing properties and a minimal diuretic dose of 0.001 mg kg-1, 200 times lower than torasemide.

Plasma Na-K ATPase inhibitor activity and intracellular ions during hemodialysis.

We have investigated the relationship between plasma Na-K ATPase inhibitor activity (EDLS) and intracellular ions in 37 uremic hemodialysed hypertensive patients, and in 20 normotensive non uremic controls (NC). As compared with the NC population, significantly enhanced values for erythrocyte (RBC) Na, Ca, platelet cytosolic Ca and EDLS were observed in all the uremic patients tested just before a dialysis session, as well as a decrease in RBC Ca ATPase and in the platelet pH. In uremia, significant correlations have been noted between RBC Na and platelet Ca (r = 0.6) or systolic BP (r = 0.45); between platelet Ca and systolic blood pressure (r = 0.8) or diastolic BP (r = 0.5) and between EDLS and RBC Na, Ca or platelet Ca (r = 0.5). Anti-hypertensive treatment has no influence on these parameters. During dialysis, a significant decrease has been noted in RBC Na, Ca, platelet Ca, SBP (only in untreated patients) and EDLS and an increase in RBC Ca ATPase and platelet pH. These modifications are significantly correlated with the weight change.

[Hypertension and pregnancy]. / Hypertension et grossesse.

Hypertension during pregnancy and its complications are the most important cause of maternal and foetal death and morbidity. The chronic primary hypertension can be differentiated from the dysgravidia by anamnestic, biological, clinical and technical investigations. However the diagnosis remains difficult and the renal needle biopsy can help to ascertain it. The pathogenesis of dysgravidia is still obscure: the placental ischemia leads to a slow disseminated intravascular coagulation state with renal injury, while a vascular hyperreactivity leads to an increase of the resistance, a relative hypovolemia and lowering of cardiac output. The treatment and remote prognosis of the hypertensive disease associated with the pregnancy are summarized. The antihypertensive drugs improve the maternal prognosis while jeopardize the foetal outcome.

Hypertension and left ventricular hypertrophy.

In response to high blood pressure, left ventricular hypertrophy develops. But in hypertension, the myocardial hypertrophied structure is abnormal. The prevalence of this hypertrophy is influenced by age, gender, weight, race, genetics and the severity of high blood pressure. By echocardiography, it has been possible to detect non invasively and more precisely this hypertrophy and its anatomical pattern which is not uniform. This cardiac response is influenced by hemodynamic but also by non hemodynamic factors, but the exact mechanisms are not yet well understood. The humoral and tropic factors particularly affect the cardiac remodeling. Left ventricular hypertrophy has been noted by itself to be an independent risk factor for sudden death, ventricular arrhythmias, myocardial ischemia, and heart failure. Very early hypertension, diastolic dysfunction is noted. The progression to systolic failure in moderate hypertension usually occurs over several decades. According to the worse prognosis of left ventricular hypertrophy, it has been suggested that the reversibility of this anatomical modification by antihypertensive treatment is beneficial. Preliminary data support this idea.

Belgian peer review experience on the Achille's Heel in haemodialysis care: vascular access.

AIMS: In order to improve the supervision and to evaluate the quality of care in dialysis units, a national project was promoted as a Peer Review. It consisted of systematic, continuous and critical evaluation of the care and the application of international guidelines and compared the reality of care with standards. METHOD: The first chart consisted of the evaluation of infectious episodes of vascular access. This point is particularly relevant since infection represents the second cause of mortality in haemodialysis. A questionnaire concerning each patient was designed. Questions concerned the description of vascular access and the related infectious events. Each questionnaire included 21 items. The project involved 29 dialysis centres, 1,644 patients and 1,775 vascular accesses. The database included 90,525 data. RESULTS: Among the 29 centres, the native arteriovenous fistula (AVF) is the first choice (67.5%) in vascular access, but the proportion of AVF decreases with age contrary to the catheter, which is more frequently chosen, in older patients. Independent of age, 20% of hospitalisations are among patients with catheters and only 7% among patients with AVF. The RR (relative risk) of being hospitalised (any complication of vascular access) is 1.68 for patients with catheters compared to patients with AVF. The rate of infections does not increase with age but is higher for patients with catheters (RR = 2.26). The number of infections appears to be dependent on the staphylococcus aureus carriage in the year. CONCLUSIONS: This first step allows each centre to compare itself to others in an anonymous way. This approach should lead to specific recommendations to improve the quality of care in dialysis units.

[Effect of long-term administration of vasodilators and "antitrophic" agents on the structure and function of the heart in hypertensive rats]. / Effets de l'administration chronique d'un vasodilatateur et d'un agent "antitrophique" sur la structure et la fonction du coeur de rat hypertendu.

In this study, we determined whether the persistency of cardiac hypertrophy after chronic vasodilation therapy with minoxidil (minox) was associated with functional or metabolic alterations in hypertensive rat hearts before, during and after an ischemic insult. In addition, we investigated the effects of the simultaneous administration of difluoromethylornithine (dfmo), a substance that could block hypertrophy by a direct inhibition of protein synthesis. Four groups of male Wistar rats were prepared: 1) normotensive controls (n = 8), 2) untreated renovascular hypertensive rats (HT, n = 15), 3) hypertensives treated with minox (8 mg/kg, n = 19), 4) hypertensives treated with minox and dfmo (1.7 g/kg, n = 20). After 21 days of treatment, the animals were sacrificed. In a small number of hearts, ornithine decarboxylase (ODC) activity was assayed in order to verify that dfmo, which is a suicide inhibitor of ODC, had effectively interrupted the polyamines pathway. The other hearts were prepared for retrograde perfusion at 35 degrees C and at constant flow (10 ml/min x g). Cardiac function was monitored via the balloon inserted in the left ventricle (LV) and the following protocol was applied: a) baseline period (24 min), b) ischemia (24 min), c) recovery (36 min). Finally, the hearts were weighed and LV wall thickness and inner radius were measured. Blood pressure was maintained near normotension in the two treated groups. Mean systolic pressure (in mmHg) was 145 +/- 4 with minox and 144 +/- 3 with minox + dfmo versus 181 +/- 4 in the HT group (p less than 0.0001).(ABSTRACT TRUNCATED AT 250 WORDS)

[Concentration of free intracellular magnesium in the myocardium of spontaneously hypertensive rats treated chronically with calcium antagonist or angiotensin converting enzyme inhibitor]. / Concentrations de magnésium intracellulaire libre dans le myocarde de rats spontanément hypertendus traités chroniquement par antagoniste calcique ou inhibiteur de l'enzyme de conversion.

In this study, we determined a) whether chronic antihypertensive treatment could alter myocardial free intracellular magnesium concentrations, b) whether changes in magnesium concentration would correlate with resistance to anoxia of hypertensive rat hearts. Six-month old male spontaneously hypertensive (HT) rats (n = 11) were compared to rats from the same strain treated with a calcium channel antagonist, nitrendipine (60 mg/kg/j; n = 11) or with a converting-enzyme inhibitor, perindopril (2 mg/kg/j; n = 9) during three months. The hearts were perfused in retrograde isovolumic mode and submitted to a standardized anoxia-recovery protocol. Aortic perfusion pressure and left ventricular pressure were constantly monitored. P-31 NMR spectra were simultaneously recorded and allowed to quantify the changes in myocardial inorganic phosphate, phosphocreatine and ATP. The pH was derived from the chemical shifts of inorganic phosphate and phosphocreatine, and the free intracellular magnesium concentration from the alpha-beta chemical shifts of ATP. Both treatments lowered systolic blood pressure and reversed left ventricular hypertrophy, perindopril being slightly more efficient at the dose administered. Intracellular magnesium concentration, calculated from the P-31 NMR spectra, was 277 +/- 17 microM in the untreated hypertensive group, 311 +/- 15 microM in the nitrendipine group and 401 +/- 17 microM in the perindopril group (p < 0.001 versus untreated and nitrendipine). There was a significant correlation between intracellular magnesium concentration and left ventricular developed pressure at the early stage of post-anoxic recovery (r = 0.61; p < 0.01). P-31 NMR spectroscopy demonstrates an increase in myocardial free intracellular magnesium concentration following chronic administration of an angiotensin-converting enzyme inhibitor, perindopril, spontaneously hypertensive rats.(ABSTRACT TRUNCATED AT 250 WORDS)

[Polyamines and cardiovascular hypertrophy in experimental hypertension]. / Polyamines et hypertrophie cardiovasculaire dans l'hypertension expérimentale.

UNLABELLED: Biochemical mechanisms which control cardiac and vascular response to hypertension are still unclear. Modifications of polyamines (putrescine, spermine, spermidine) may play a role in this phenomenon, since these molecules have been shown of importance in the control of tissue growth. Ornithine Decarboxylase (ODC) catalyses the first and probably the rate limiting step in the biosynthesis of the polyamines. We thus attempted to detect modification of ODC activity in renovascular hypertension in the rat (G1K-1C) and tried to correlate hypertrophic response and ODC activity in the aorta (Ao), the left (LV) and the right (RV) ventricles. In this experimental model, the aortic ODC activity increased at day 1 and 2, after clipping the renal artery, whereas in the LV the ODC activity increased after day 3 but stay high at least until day 7. The peak of ODC activity comes before the increase in DNA synthesis which occurs at day 4 in Ao, and the increase in protein turnover observed at day 7 in LV. No significant variation of ODC activity neither changes in DNA or protein biosynthesis rate are observed in the RV. In parallel with changes in ODC activity, an increase in spermidine and spermine content and mainly in the spermidine/spermine ratio is observed in the Ao and the LV confirming stimulation in polyamine biosynthesis in hypertensive tissues. IN CONCLUSION: increase in ODC activity is observed only in these tissues that will develop hypertrophy or hyperplasia and this modification is observed before any increase in nucleic acids or protein tissues content or turnover rate.

[Does ambulatory blood pressure measurement allow a better definition of arterial hypertension?]. / La mesure ambulatoire de la pression artérielle permet d'améliorer la définition de l'hypertension artérielle.

The lack of effect of treatment of mild hypertension on the coronary heart disease has motivated researches for a better diagnosis of hypertension. One of the approaches presently under study uses the recording of ambulatory blood pressure using semi-automatic devices. The usefulness of these apparatus is however restricted by the lack of reference values recorded in normotensive control patients. We have recorded ambulatory blood pressure (PAA) in 24 normotensives, 22 untreated hypertensives and 45 treated hypertensive patients, and compared the data obtained to the blood pressure recorded during medical examination (PAC). If a good correlation is usually observed between PAA and PAC, very large and unpredictable discordances are frequently observed. No correlation is found between the difference PAA-PAC and the variability of PAA. This variability does not fully explain the difference observed between PAA and PAC. This variability expressed in mmHg increases with age and the level of BP. Ambulatory BP appears to be a very reproducible value which may allow to improve the definition of hypertension and there-fore the cardiovascular risk.

[Proliferative response of the arterial wall in arterial hypertension: hyperplasia versus polyploidy]. / Réponse proliférative de la paroi artérielle dans l'HTA: hyperplasie versus polyploïdie.

Proliferation changes are along with cell hypertrophy and extracellular deposit the major components of the hypertensive structural changes in large arteries. There is still some doubt about the nature of the proliferative changes: hyperplasia or polyploidization. The aorta and the tail artery of SHR and Goldblatt one-kidney, one clip hypertensive rats (RVHR) were studied at different ages and hypertensive stages. After enzymatic dispersion, cell relative DNA content was assayed by flow cytofluorimetry and by Feulgen microdensitometry. Tissue total DNA content was assayed by fluorimetry. The increase in diploid and tetraploid cells within the hypertensive arteries was further calculated. In the RVHR, hypertension is of very rapid onset and reaches a plateau within 20 days (compared to the normotensive Wistar, systolic BP is 32 mmHg at 15 days, 52 mmHg at 40 days, 45 mmHg at 90 days). An increase in total aortic DNA content (DNA: 32 micrograms at 15 days, 31 micrograms at 40 days, 40 micrograms at 90 days) is found before the development of a significant polyploidy (polyploidy in per cent: 2.3 p. 100 at 15 and 40 days; 12.0 p. 100 at 90 days). Proliferation changes in this model appears to be hyperplasia at the acute phase and polyploidy at the chronic phase. The course of hypertension is slower and less severe in the SHR (compared to the WKY, systolic BP: 0 mmHg in 4 weeks, 17 mmHg in 8 weeks old and 33 mmHg in 35 weeks old rats).(ABSTRACT TRUNCATED AT 250 WORDS)

[Does dopamine play a role in renal anomaly in sodium excretion, a marker for hereditary predisposition to arterial hypertension?]. / Anomalie rénale de l'excrétion sodée, un marqueur de la prédisposition héréditaire à l'hypertension artérielle, rôle de la dopamine?

Since Dahl's observation, a renal defect os sodium excretion is proposed as one of pathogenetic mechanism of hypertension (HTA). Our study has tried to verify this concept in 20 young normotensives with (n = 12) and without (n = 8) familial predisposition to HTA, allowing to test the genetic transmission of such potential renal abnormality of sodium balance. Each people was submitted to 3 different Na diet (20, 170 and 340 mM NaCl) each for 1 week. At each visit, blood pressure, vascular resistances, biological values were determined at rest (plasma renin activity, creatinine clearance, 24 hours before the test, catecholamines, aldosterone and ion urinary excretion). Then 1 liter of isotonic saline was perfused in 30 minutes with measures of blood pressure and 3 hours urinary dopamine and Na excretion. During the low and medium Na diets, but not during the high Na diet, the natriuresis and dopamine excretion were lower in the 3 hour urine collection in patients with a family history of HTA (p less than 0.02 and p less than 0.005, respectively). No other clinical or biological difference was noted between the 2 groups. Thus, genetic hypertensive predisposition seems to be characterized by a lower Na excretion during acute Na loading in normal or depleted Na diet, linked to an impaired urinary dopamine excretion. These findings suggest that the defect responsible for the susceptibility to sodium intake is at the kidney level. Some dopamine agonists would be of great therapeutical value in treating such patients when blood pressure begins to rise.