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Biomedical subjects

J Amar

Publications and source records attributed to J Amar.

At least 55 records · Page 3Linked to original sources
PubMed1992

[For which hypertensive patient should angiotensin-converting enzyme inhibitor be prescribed or forbidden?].

Angiotensin-converting enzyme (ACE) inhibitors act by lowering the level of angiotensin II. The therapeutic benefits of these drugs and their potential side-effects therefore result from suppression of the physiological effects of angiotensin II. It is rational to prescribe an ACE inhibitor when the renin-angiotensin system is activated, as in renin-dependent essential hypertension, malignant hypertension and hypertension associated with heart failure. The beneficial effects of ACE inhibitor must be weighed against the special risks of renovascular hypertension: risk of renal artery thrombosis in case of unilateral stenosis and risk of renal failure if the stenosis is bilateral or affects a solitary kidney. In some situations the renin-angiotensin system is not directly involved in hypertension but may play a local haemodynamic role, as in some cases of primary or diabetic nephropathy. In such case the ACE inhibitors are thought to exert a protective effect. ACE inhibitors were reputed to be less effective in the elderly than in younger patients, but we now know that they can be prescribed with equal success in both instances to reduce peripheral resistance and improve regional blood flow as well as arterial compliance. Finally, ACE inhibitors can be prescribed, albeit with limited effectiveness, when the renin-angiotensin system is not activated, as in low renin hypertension and idiopathic hyperaldosteronism due to adrenal hyperplasia. They are ineffective in case of Conn's adenoma and contra-indicated in pregnant women.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1992

Serum Lp(a) as a discriminant marker of early atherosclerotic plaque at three extracoronary sites in hypercholesterolemic men. The PCVMETRA Group.

To investigate the role of lipoprotein (a) (Lp[a]) as an atherogenic condition related to hypercholesterolemia, we studied the serum concentration of Lp(a) as measured by immunonephelometry in relation to the presence of asymptomatic echographic plaques in the peripheral arteries of 103 untreated hypercholesterolemic, normotensive, middle-aged men. Plaque was found at carotid, aortic, and femoral sites in 36%, 51%, and 53% of subjects, respectively. The Lp(a) level was higher in the group with carotid plaques than in the group without (0.29 +/- 0.20 versus 0.17 +/- 0.14 g/l, p < 0.01), not significantly higher in the group with aortics plaque than in the group without (0.24 +/- 0.19 versus 0.19 +/- 0.16 g/l), and not different between groups with and without femoral plaques (0.21 +/- 0.18 versus 0.22 +/- 0.17 g/l). A logistic regression analysis confirmed that Lp(a) was associated with carotid plaques (p = 0.004), independent of other risk factors. However, in patients with low density lipoprotein cholesterol values above the group median value (4.7 mmol/l), Lp(a) was associated not only with carotid plaques (p < 0.01) but also with aortic plaques (p < 0.05), as well as with the number of diseased sites (p = 0.02). In contrast, in patients with low density lipoprotein cholesterol levels below or equal to 4.7 mmol/l, Lp(a) only remained associated with carotid plaques (p < 0.05). Thus, in symptom-free, hypercholesterolemic men, early atherosclerosis was influenced by serum Lp(a), particularly in the carotid arteries, as well as by the presence of a higher level of low density lipoprotein cholesterol.

Adult↗
PubMed1991

Herpes simplex hepatitis in a patient with psoriatic arthritis taking prednisone and methotrexate. Report and review of the literature.

Herpes simplex hepatitis is a rare disease in adults and with high mortality (81%). Most cases are seen in immunocompromised hosts or in the third trimester of pregnancy. A 43-year-old woman with psoriatic arthritis, treated with prednisone and methotrexate (MTX), presented with an acute abdomen and elevated liver enzymes. The diagnosis was made by liver biopsy. MTX was stopped and acyclovir was started. The patient survived. The diagnosis of Herpes simplex should be suspected in immunocompromised hosts and established by liver biopsy and viral cultures. Treatment includes parenteral acyclovir and discontinuation or reduction of immunosuppressive therapy.

Adolescent↗
PubMed1990

Antithrombotic potencies of heparins in relation to their antifactor Xa and antithrombin activities: an experimental study in two models of thrombosis in the rabbit.

Our purpose was to determine the relative contribution of the antifactor Xa and antithrombin activities of heparin to its antithrombotic potency. The antithrombotic activities of unfractionated heparin (UH), two low molecular weight heparins (LMWH, CY 216 and CY 222) with increasing anti-factor Xa/antithrombin ratio and a synthetic pentasaccharide (PS) with high affinity to antithrombin III and no antithrombin activity were evaluated. In the Wessler-thromboplastin model, the most potent antithrombotic agent, on a weight basis, was UH followed by CY 216, CY 222 and the PS which was 40 times less potent than UH. On an antithrombin unit basis, the antithrombotic potencies of UH, CY 216 and of CY 222 were equivalent. Thus, in this model, the antithrombotic effect results from the catalytic action of UH or LMWH on thrombin inhibition. In the Wessler-serum model, on a weight basis, the antithrombotic effectiveness of UH was unchanged, those of CY 216 and CY 222 were doubled, and that of the PS was increased 10 times. On an anti-factor Xa unit basis, CY 216 was as effective as UH, and PS as effective as CY 222. On an antithrombin unit basis, CY 216 and CY 222 were equivalent and more potent than UH. Thus, in this model, the antifactor Xa activity of heparin becomes important for its antithrombotic property. After a single subcutaneous injection of 1000 antifactor Xa U/kg, the antithrombotic effects of UH were maintained for more than 14 h in the two models. After injection of the same dose of CY 216 significant antithrombotic effects were observed only for 9 h, in the Wessler-thromboplastin model but for 18 h in the Wessler-serum model. At that time, no detectable antithrombin activity was measurable in the plasma while 0.11 units of antifactor Xa activity/ml was detected. Thus, the relative contribution of the anti-factor Xa and antithrombin activities to the antithrombotic effect of a LMWH differs according to the nature of the thrombogenic stimulus.

Animals↗
PubMed1990

Prevention of stress-induced hypertension in hypertensive patients.

The aim of the study was to assess the course of the alerting reaction during an effective antihypertensive treatment, and to discuss its interference with the conduct of therapy. In 28 patients suffering from mild to moderate hypertension, the basal blood pressure was measured in an outpatient clinic according to a standardized procedure, first by a nurse, then by a 12-min recorded monitoring, and then by a physician using a mercury sphygmomanometer with the patient in the upright and then the supine position. In comparison with the monitoring (mean values recorded at 6, 9, and 12 min), there was a significant increase in diastolic and systolic blood pressure taken by the nurse and by the physician, which diminished at the end of the visit with the physician. Patients then received 10 mg of bisoprolol each morning and presented again on day 30 and day 60, following the same procedure and under identical conditions. Despite the desired antihypertensive effect, the alerting reaction persisted at each visit up to the end of the study, being unchanged in the case of the systolic blood pressure and accentuated in the case of the diastolic blood pressure. Our results confirm those of previous investigations showing that even an effective antihypertensive therapy is unequivocally associated with a persisting alerting reaction irrespective of the antihypertensive drug applied. Thus, patients may be exposed to the potential risk involved with false failures and unnecessary overtreatment. The physician must compare his or her own measurements with readings made outside the consulting office and must program ambulatory blood pressure monitoring in the case of discrepancy. This is a suitable means of confirming and validating blood pressure measurements, as this method does not record the alerting reaction.

Adrenergic beta-Antagonists↗
PubMed1990

[Ambulatory blood pressure in hypertension with dysautonomia].

The purpose of the study was to evaluate the interest of ambulatory blood pressure (BP) recording (ABPR) in the management of arterial hypertension (AH) with dysautonomia. The study concerned 8 hypertensive patients (pts), 5 men, 3 females 52 +/- 10 years old, with orthostatic hypotension (OH): BP was 162 +/- 19/87 +/- 16 mmHg and 129 +/- 15/76 +/- 8 mmHg in lying and standing position respectively. In two cases AH was associated with a central degenerative disorder whereas the six other pts had a diabetic dysautonomia: bad metabolic control (HBA1c 14.4 +/- 2.7%), and incipient or over nephropathy (4 pts). ABPR was performed in all pts during 24 hours (space-labs system). In these hypertensive pts with OH, the mean 24 hour-BP was surprisingly normal at 128 +/- 11/76 +/- 6 mmHg. ABPR demonstrated the loss of nocturnal decline in BP: diurnal and nocturnal BP were respectively 125 +/- 13/74 +/- 6 mmHg and 133 +/- 16/78 +/- 10 mmHg (NS). 6 of 8 pts had an increase in BP at night resulting for the population (n = 8) in a nocturnal increase (%) of + 5.6%, this pattern widely differs from controls--13%. The decrease in heart rate during sleep was blunted but significant from 89 +/- 9 b/min to 81 +/- 9 b/min (p 0.01). Diurnal and nocturnal BP variability (V), assessed by variation coefficient were not significantly different: SBP-V was 10.3 +/- 6.4% day and 12.3 +/- 4.2% night, DBP-V 7.5 +/- 6.3% day and 12.5 +/- 3.1% night.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

[Neurogenic arterial hypertension in humans].

The purpose of this study was to investigate baroreflex activity in hypertensive patients with orthostatic hypotension (OH) due to sinoaortic baroreceptor denervation. The study concerned 3 patients (pts), 58-63 years, mean age 60.6 +/- 2 with both arterial hypertension (paroxysms recorded at 250/130 mmHg) and OH. They received radiation therapy to the entire cervical area for neoplasm, 9.6 +/- 2.8 years ago and had a carotid murmur without significant stenosis. Every pt had a severe and symptomatic OH: blood pressure (BP) and heart rate (HR) were respectively 163 +/- 17/105 +/- 7, 82 +/- 5 b/mn in lying position and 82 +/- 16/53 +/- 9 mmHg, 99 +/- 1 b/mm in standing position. The standing-induced increase in HR was lower (delta HR = + 17.3 b/mn) than expected; atropine (0.02 mg/kg) infusion and cold pressor test were ineffective; the massage of sinocarotid receptors induced a slight decrease in HR (delta HR = - 8 b/mn) and BP was not modified by Valsalva's maneuver. Infusion of norepinephrine (0.016 mg/mn) performed in one pt, increased BP without effect on HR. Platelet alpha 2-adrenoreceptors (alpha 2AR) evaluated by (3H) Yohimbine binding showed a significant increase in alpha 2AR number (Bmax), without any significant change in affinity (KD) when compared with normotensive and essential hypertensive pts: (table; see text) This study described an unusual etiology of a paroxysmal hypertension with orthostatic hypotension, demonstrated the impairment of baroreflex activity and suggested the potential interest of platelet alpha 2 adrenoceptors measurement to evaluate sympathetic tone in these patients.

Blood Pressure↗
PubMed1986

Crypt production in normal and diseased human colonic epithelium.

New crypts are added continuously to the adult mouse intestinal epithelium by a process of crypt replication. Branching crypts found in the epithelium represent a stage in the process of crypt replication. In "normal" human colonic epithelium we found a small but definite percentage of branching crypts, 0.44 +/- 0.16, indicating that new crypts are being produced at a low rate in this epithelium. Significantly higher (P less than .001) percentages of branching crypts, 30.4 +/- 5.75, 15.1 +/- 1.08, and 13.2 +/- 1.05, were found in diseased colonic epithelium from patients with ulcerative colitis, Crohn's disease, and multiple polyposis, respectively. These results may be interpreted as suggesting that the rate of crypt production in human colonic epithelium is increased in a number of disease states. We concluded that, as in the mouse intestinal epithelium, the rate of the crypt replication process in human colonic epithelium is plastic and may respond to a variety of conditions.

Aged↗
PubMed1984

Methods for the determination of epithelial cell kinetic parameters of human colonic epithelium isolated from surgical and biopsy specimens.

The purpose of this study is to introduce the application of new approaches to the determination of human colonic epithelial cell kinetic parameters. The isolation of pure and intact colonic epithelium from both surgical and biopsy specimens forms the basis of these approaches. The isolated epithelium is used in the determination of cell kinetic parameters by (a) flow cytometry, (b) Coulter counting, (c) dried cell preparations, and (d) crypt squashes. Using these methods, the following results were derived. The proportion of cells in the various phases of the cell cycle in the sigmoid epithelium was determined to be 81.6% +/- 2.15% (means +/- SE) in G1/G0 phase, 15.2% +/- 1.86% in S phase, and 3.2% +/- 0.62% in G2 + M phases. In the rectal epithelium, there were 79.6% +/- 3.35% in G1/G0 phase, 16.4% +/- 4.86% in S phase, and 4.08% +/- 1.90% in G2 + M phases. The total cell population in sigmoid epithelium was approximately 4.2 X 10(6) +/- 5.46 X 10(5) cells per cm2, and there were approximately 2.5 X 10(3) +/- 1.57 X 10(2) cells in each colonic crypt. Therefore, the number of crypts per square centimeter of human sigmoid mucosa could be estimated to be approximately 1.68 X 10(3). Lastly, in sigmoid epithelium, columnar cells of human sigmoid mucosa could be estimated to be approximately 1.68 X 10(3). Lastly, in sigmoid epithelium, columnar cells accounted for 76.3% +/- 6.18% of the epithelial cells, whereas the remaining epithelial cells, 23.7% +/- 4.08%, consisted of mucous cells.

Cell Count↗
PubMed1983

[Isolated retroperitoneal hydatid cyst. Apropos of 2 new cases].

Hydatid disease in endemic countries is common but an isolated retroperitoneal localisation is rare. After a review of the aetiopathogenesis and clinical aspects, the authors express the opinion that safe, rapid and reliable technique of echotomography is the key investigation in obtaining a positive diagnosis. In terms of its course, the histopathological appearances are those of a locally malignant tumour which as a preferential and severe effect on renal function. Surgery is the only valid method for eradication of the parasite and freeing the urinary tract.

Adolescent↗
PubMed1981

Respiratory neuromuscular output during breath holding.

The involuntary respiratory muscle contractions that occur during breath holding were found in almost all of 52 subjects and were regular in a majority. In detailed studies, subjects rebreathed a mixture of 8% CO2 in O2 and then held their breath on an occluded mouthpiece, with glottis open, at functional residual capacity. Contractions monitored as waves of negative pressure were reproducible and increased in amplitude and frequency through the breath hold, but the breakpoint did not always correspond to the same pressure or frequency. Frequency and the time derivative of pressure (dP/dt) of contractions were much higher during breath holding than frequency of breathing and dP/dt of occluded breaths at the same gas tensions during rebreathing. Contractions were reduced in amplitude after the subject took three breaths without altering gas tensions. The results are consistent with the hypothesis that contractions contribute to dyspnea in breath breath holding, but there is not a simple correlation between their magnitude and the degree of dyspnea.

Abdominal Muscles↗
PubMed1979

[Duodenal stimulation of insulin secretion. Role of intestinal villi].

Insulin secretion is partially regulated by hormonal and nervous signals arising from the duodenum. To ascertain the role of absorption through the villi on insulin secretion, the blood levels of immunoreactive insulin (IRI) in 13 normal children (T) were compared with those in 13 with flat jejunal mucosae (MJP). The bowel was stimulated by the infusion of Nutramigen direct into the duodenum at 4 ml/mn m2. In the control group (T) IRI increased from the 10th minute of the perfusion to reach a plateau after the first hour (256 +/- 107 pmol/l). In the MJP group the rise of IRI was delayed and the plateau lower (169 +/- 25 pmol/1) but the difference in the two groups was not statistically significant. During the first 10 minutes when there is no significant change in blood glucose levels IRI levels increased in the T group (p less than 0.01) but there was no significant change in the MJP group. These results suggest that when villi are intact stimulation of the duodenum causes insulin secretion; but when there are no villi, there is a delay in the secretion.

Blood Glucose↗
PubMedDate not supplied

[Prevention in cardiovascular pathology].

National and international recommendations on the management of arterial hypertension and hypercholesterolemia suggest a treatment decision based on the evaluation of absolute cardiovascular risk. In order to evaluate the cardiovascular risk level, Anderson's equation (Framingham) has been proposed but does not apply to the French population. In medical practice, cardiovascular risk has to be appreciated according to the estimated cardiovascular risk of the country or area. The limits of a decision based on cardiovascular risk have been emphasized, particularly the balance age/life expectancy in respect of early prevention of atherosclerosis. However, the benefit of treatment of hypertension with beta-blockers, diuretics and recently ACE inhibitors and calcium antagonists or hypercholesterolemia with statins has been clearly stated--the higher the cardiovascular risk the higher the benefit. Secondary prevention in patients with major cardiovascular events is effective and necessary. The discussion concerns only primary prevention and from an economic point of view may concern patients at high cardiovascular risk. The general population have to be informed on cardiovascular risk factors, and patient education must be encouraged and developed via the healthcare network.

Antihypertensive Agents↗