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Biomedical subjects

M Brahimi

Publications and source records attributed to M Brahimi.

17 recordsLinked to original sources
PubMed2003

[Amyloidosis and pleural calcification].

INTRODUCTION: Pulmonary diseases during the course of generalised amyloidosis are principally represented by tracheobronchial involvement and diffuse parenchymal localizations. CASE REPORT: The authors report the case of a 66-year-old woman presenting with pleural amyloidosis in the context of generalised amyloidosis. Thoracoscopy performed in the investigation of recurrent transudative pleural effusions found evidence of an inflamed parietal pleura with areas of calcification. Pleural biopsies confirmed amyloid infiltration pleural ossification. Talc pleurodesis was performed. CONCLUSIONS: The authors' conclusion is that, meeting an unexplained pleural effusion even transudative during the course of a generalised amyloidosis, the thoracoscopy is the diagnosis key test as it allows moreover a pleural pleurodesis to be performed.

Aged↗
PubMed2001

[Relationship between vasosympathetic activity and insulin resistance in normotensive and mildly hypertensive obese patients].

Several studies have well demonstrated that obesity is associated with changes in cardiovascular vagosympathetic activity. The aim of the present work was to evaluate this activity in normotensive and in mildly hypertensive obese patients, and to correlate this activity with clinical and biological indexes of insulin resistance. Heart rate (HR) and systolic blood pressure (sBP) were examined by spectral analysis in 70 normotensive obese patients (group 1), 32 mildly hypertensive obese patients (group 2), and 21 controls. The high frequency peak of HR variations at a controlled breathing rate (vagal activity) was significantly reduced in both groups (p < 0.001). The mid frequency peak of sBP in the standing position (sympathetic activity) was similar in both groups and in the control group. In groups 1 and 2, the high frequency peak correlated negatively with age (p = 0.005 and 0.034 respectively). In group 1, the mid frequency peak correlated positively with fat mass, fasting plasma insulin and triglyceride levels, and insulin resistance index (p < or = 0.03). In group 2, the mid frequency peak correlated positively with fasting insulin and insulin resistance index (p = 0.006 and 0.007 respectively). This study shows that, in obese patients: 1. cardiac vagal activity is reduced in normotensive and mildly hypertensive subjects; 2. vascular sympathetic activity is unchanged in means but may be increased as a consequence of adiposity, hyperinsulinemia and insulin resistance, and this increase is likely to be involved in the increase of blood pressure.

Adult↗
PubMed2001

[Arterial rigidity and cardiovascular vagosympathetic activity in normotensive and hypertensive obese patients and type 2 diabetics].

An increase in arterial rigidity is associated with a poor cardiovascular prognosis. Several studies have suggested that an increase in sympathetic activity may be involved in essential hypertension. We have recently shown that vagal control of heart rate (HR) variations during standardised tests is altered in normotensive obese and diabetic patients. The aim of the present study was to compare cardiovascular vagosympathetic activity in obese and type 2 diabetic patients, either normotensive or hypertensive, and to investigate the relationship between pulse pressure (an index of arterial rigidity) and sympathetic activity in this population. Seventy normotensive obese and 32 mildly hypertensive obese patients, 18 normotensive type 2 diabetic patients and 14 mildly hypertensive type 2 diabetic patients were compared with 21 control subjects. Finapres studied HR and blood pressure variations. In the four groups, during a 6-min period at a controlled breathing rate, the high frequency peak of HR variations was significantly reduced (p < 0.001). The mid-frequency peak of systolic BP variations in the standing position, which depends on sympathetic activity, did not differ significantly between the four groups and control subjects. In obese and diabetic hypertensive patients, this peak correlated significantly with pulse pressure measured in the lying position (r = 0.379; p = 0.043 and r = 0.81; p < 0.0001, respectively). This study 1, confirms that vagal control of HR variations is reduced to a similar extent in obese and diabetic patients; and 2, suggests that cardiovascular sympathetic activity is relatively increased in these patients without significant difference between normotensive and hypertensive patients, but interestingly that the increase in arterial rigidity is associated with a higher sympathetic activity.

Adult↗
PubMed2000

Impact of pulse pressure on degree of cardiac hypertrophy in patients with chronic uraemia.

OBJECTIVE: To evaluate the degree of cardiac hypertrophy in patients with end-stage renal disease (ESRD) in comparison with that in patients with uncomplicated hypertension and in patients with peripheral vascular disease (PVD), at the same values of mean blood pressure. DESIGN: Thirty-six ambulatory hypertensive patients were investigated, 11 with ESRD, 14 with PVD and 11 with uncomplicated hypertension, matched for age, sex, mean arterial pressure and antihypertensive drug treatment. METHODS: Cardiac mass was determined using M-mode echocardiography together with measurement of systemic blood pressure and the ratio between ankle and arm systolic blood pressures. RESULTS: At the same mean arterial pressure, patients with ESRD developed a greater degree of cardiac hypertrophy in comparison with those with uncomplicated hypertension (P < 0.01) and patients with PVD (P < 0.05). The pulse pressure was significantly greater in patients with ESRD than in those with uncomplicated hypertension (P< 0.01) and those with PVD (P< 0.05). Multiple regression analysis showed that only pulse pressure was positively correlated to cardiac mass (r= 0.62, P< 0.001), suggesting a predominant impact of pulse pressure on left ventricular mass in patients with ESRD. CONCLUSIONS: In patients with chronic uraemia, left ventricular hypertrophy seems to be strongly and independently associated with pulse pressure.

Blood Pressure↗
PubMed1999

Plasma insulin, plasminogen activator inhibitor, and ankle-brachial systolic blood pressure ratio in overweight hypertensive subjects.

BACKGROUND: In hypertensive subjects, the ratio between ankle and brachial systolic blood pressure (ABI) has been shown to be an independent risk factor for cardiovascular diseases, particularly in the elderly. Plasma insulin may be an important interconnecting factor explaining this observation. PURPOSE: In a population of middle-aged subjects with essential hypertension and moderate overweight, we identified whether the decrease in the ABI ratio was associated with the clinical and biochemical factors involved in resistance to insulin. Patients with diabetes and/or arteriosclerosis obliterans of the lower limbs were excluded from the population. Subjects were or were not on antihypertensive therapy. RESULT: On the basis of univariate correlations, the ABI ratio was found to be significantly and negatively associated not only with the degree of abdominal fat distribution, but also with the usual biological features of resistance to insulin: plasma triglycerides and cholesterol; plasma glucose and insulin; and plasminogen activator inhibitor (PAI) antigen. In a multivariate analysis in subjects with untreated hypertension, the ABI ratio was significantly and negatively associated with only three variables: age, plasma insulin and PAI antigen. In treated hypertensive subjects, only the role of age and insulin remained significant. CONCLUSION: Since the alterations of the ABI ratio may be considered as a marker of the changes in the structure and function of arteries of the lower limbs, the study provides evidence that plasma insulin and PAI antigen, independently of the presence of significant atherosclerotic occlusive lesions, are susceptible to alter the pressure wave transmission in conduit arteries of the lower limbs.

Adult↗
PubMed1999

Dynamics of rabies virus quasispecies during serial passages in heterologous hosts.

To understand the mutations and genetic rearrangements that allow rabies virus infections of new hosts and adaptation in nature, the quasispecies structure of the nucleoprotein and glycoprotein genes as well as two noncoding sequences of a rabies virus genome were determined. Gene sequences were obtained from the brain and from the salivary glands of the original host, a naturally infected European fox, and after serial passages in mice, dogs, cats and cell culture. A relative genetic stasis of the consensus sequences confirmed previous results about the stability of rabies virus. At the quasispecies level, the mutation frequency varies, in the following order: glycoprotein region (21.9 x 10(-4) mutations per bp), noncoding sequence nucleoprotein-phosphoprotein region (7.2-7.9 x 10(-4) mutations per bp) and nucleoprotein gene region (2.9-3.7 x 10(-4) mutations per bp). These frequencies varied according to the number, type of heterologous passages and the genomic region considered. The shape of the quasispecies structure was dramatically modified by passages in mice, in which the mutation frequencies increased by 12-31 x 10(-4) mutations per bp, depending on the region considered. Non-synonymous mutations were preponderant particularly in the glycoprotein gene, stressing the importance of positive selection in the maintenance and fixation of substitutions. Two mechanisms of genomic evolution of the rabies virus quasispecies, while adapting to environmental changes, have been identified: a limited accumulation of mutations with no replacement of the original master sequence and a less frequent but rapid selective overgrowth of favoured variants.

Animals↗
PubMed1998

Plasma insulin and ankle on brachial systolic blood pressure ratio in overweight men with hypertension.

BACKGROUND: Hypertension is often associated with multiple metabolic abnormalities included in the insulin resistance syndrome. In hypertensive individuals, the ratio between ankle and brachial systolic blood pressure (ABI) is considered to be an independent cardiovascular risk factor. Insulin resistance has not been studied in relation to ABI ratio in men with essential hypertension and who are moderately overweight. OBJECTIVE: To identify whether a decrease in the ABI ratio is associated with the degree of abdominal obesity and, hence, with the biochemical characteristics of resistance to insulin. METHODS: In 166 overweight men with mild-to-moderate essential hypertension, insulinaemia was measured using radioimmunoassay. The ABI ratio was measured by using a pressure cuff of appropriate diameter, a standard mercury sphygmomanometer and a Doppler probe. Patients with diabetes or arteriosclerosis obliterans of the lower limbs, or both, were excluded from the study. RESULTS: The ABI ratio was significantly associated with the degree of abdominal obesity, but also with plasma triglycerides and cholesterol, low high-density lipoprotein cholesterol, plasma glucose and insulin. In a multiple regression analysis, the ABI ratio was significantly and negatively associated with only two variables: age and plasma insulin. This result was independent of age and drug treatment of hypertension. CONCLUSION: Because alterations in the ABI ratio may be considered markers of the changes in the structure and function of the arteries of lower limbs, the study provides evidence that plasma insulin, independently of atherosclerotic occlusive lesions, can significantly influence the status of conduit arteries of the lower limbs.

Adult↗
PubMed1998

Factors determining cardiac hypertrophy in hypertensive patients with or without peripheral vascular disease.

1. Coronary ischaemic disease and congestive heart failure are the principal causes of mortality in patients with peripheral vascular disease. Whether cardiac hypertrophy is present and even more pronounced in peripheral vascular disease than in other populations has never been explored.2.Twenty-five hypertensive patients were investigated, 11 without and 14 with peripheral vascular disease, matched for age, sex, mean arterial pressure and antihypertensive drug treatment. Cardiac mass was determined using echocardiography together with measurement of systemic blood pressure, ratio between ankle systolic pressure (ASP) and brachial systolic pressure (BSP), and standard biochemical parameters including natriuresis per 24 h.3. At the same mean arterial pressure, patients with peripheral vascular disease had a significantly higher cardiac mass (157+/-12 versus 116+/-6 g/m2; P<0.01), pulse pressure (81+/-5 versus 55+/-4 mmHg; P<0.01) and natriuresis (180+/-17 versus 144+/-6 mmol/24h; P<0. 01) than controls. Using univariate correlations, cardiac mass was positively associated with pulse pressure, mean arterial pressure and natriuresis, and negatively with the ASP/BSP ratio. On the basis of multivariate regression analysis, only natriuresis was positively correlated to cardiac mass.4. Patients with peripheral vascular disease develop a higher degree of cardiac hypertrophy in comparison with hypertensive subjects with the same level of mean arterial pressure. Sodium intake rather than mechanical factors seems to be the major modulating factor which influences the degree of cardiac hypertrophy.

Aged↗
PubMed1993

Improving out-patient appointment systems.

The Patient's Charter has recently set the standard for hospital out-patient clinics that patients will "be given a specific appointment time and will be seen within 30 minutes of that time". Describes the successful application of an operational research/operations management approach to out-patient appointment systems at the Royal Lancaster Infirmary. Draws the conclusion from a comparison of this and other studies that many hospitals face very similar problems with similar solutions; but that localized studies may often be required to achieve these solutions.

Appointments and Schedules↗
PubMed1992

Rapid sequence evolution of street rabies glycoprotein is related to the highly heterogeneous nature of the viral population.

The sequence of the glycoprotein gene of a street rabies virus was determined directly using fragments of a rabid dog brain after PCR amplification. Compared with that of the prototype strain CVS, this sequence displayed 10% divergence in overall amino acid composition. However only 6% divergence was noted in the ectodomain suggesting that structural constraints are exerted on this portion of the glycoprotein. A human strain isolated on cell culture from the saliva of a patient with clinical rabies had only five amino acid differences with the canine isolate, an indication of their close relatedness. These differences could have originated during transmission from dog to dog, or from dog to man, or during isolation on cell culture; they are nonetheless indicative of a genetic evolution of street rabies virus. This evolution was further evidenced by the selection of cell-adapted variants which displayed new amino acid substitutions in the glycoprotein. One of them concerned antigenic site III where arginine at position 333 was replaced by glutamine. As expected this substitution conferred resistance to a site IIIa monoclonal antibody (MAb), but surprisingly did not abolish neurovirulence for adult mice. However, a decrease in the neurovirulence of the cell-adapted variant in the presence of a site IIIa specific MAb was noted, suggesting that neurovirulence was due to a subpopulation neutralizable by the MAb. Simultaneous presence of both the parental and variant sequences was indeed evidenced in the brain of a mouse inoculated with the cell-adapted variant; during multiplication in the mouse brain, the frequency of the parental sequence rose from less than 10% to nearly 50%, indicating the selective advantage conferred by arginine 333 in nervous tissue. Altogether these results were suggestive of an intrinsic heterogeneity of street rabies virus. This heterogeneity was further demonstrated by the sequencing of molecular clones of the glycoprotein gene, which revealed that only one-third of the viral genomes present in the brain of a rabid dog had the consensus sequence. Two-thirds of the clones analyzed displayed from one to three amino acid substitutions. Such heterogeneous populations have been referred to as quasispecies, a concept which implies heterogeneous populations kept together in a dynamic equilibrium. This equilibrium could be rapidly displaced, giving the virus the capacity to adapt easily to new environmental conditions.

Amino Acid Sequence↗
PubMed1992

Ambulatory blood pressure measurement, smoking and abnormalities of glucose and lipid metabolism in essential hypertension.

OBJECTIVE: Casual (mercury sphygmomanometer) and ambulatory blood pressure measurements were determined in 61 subjects with sustained essential hypertension. DESIGN: Patients were classified into three subgroups: smokers or non-smokers; patients with or without hyperglycemia; and patients with or without plasma lipoprotein abnormality. Mean casual blood pressure were shown to be identical in these three subgroups. RESULTS: When ambulatory blood pressure was analyzed, smokers exhibited a significant increase in pulse pressure exclusively during the activity period, whereas diastolic blood pressure and mean arterial pressure (MAP) were not modified in comparison with controls. Patients with abnormal plasma glucose showed a significant increase in systolic and pulse pressure during both activity and non-activity periods, with a slight increase in MAP during the activity period. Patients with and without plasma lipid abnormality displayed similar ambulatory blood pressure. CONCLUSION: The study provides evidence that, in spite of similar casual blood pressure levels among smokers and non-smokers, as well as among those with elevated fasting glucose levels, smokers and patients with hyperglycemia have a higher systolic and pulse pressure during 24-h monitoring, pointing to the possible role of cyclic stress in the deterioration in the structure of the hypertensive arterial wall.

Blood Glucose↗
PubMed1992

Arterial and antihypertensive effects of nitrendipine: a double-blind comparison versus placebo.

Arterial effects evaluated by carotid-femoral, brachial-radial, and femoral-tibial pulse wave velocity and antihypertensive effect evaluated by 24-h ambulatory blood pressure (BP) monitoring were measured in 17 hypertensive patients before and 24 h after once-daily nitrendipine (20 mg) administration. After a 15-day placebo period, a double-blind study of nitrendipine versus placebo was performed for 1 month. After nitrendipine dosing, BP measured by sphygmomanometer 24 h after the last drug intake showed a significant decrease as compared with the pretreatment period. Ambulatory BP mean values were also significantly decreased for systolic and diastolic BP (SBP, DBP). This decrease predominated during the day but was observed nocturnally only after 6 a.m. Twenty-four hours after the last tablet intake of nitrendipine, carotid-femoral and brachial-radial pulse wave velocities were significantly reduced, whereas femoral-tibial wave velocity was unchanged, indicating that markers of arterial rigidity might be substantially modified and that the modifications were partly unrelated to BP changes. The results provide evidence that in hypertensive subjects nitrendipine 20 mg given once daily for 1 month produces an arterial effect for 24 h, in association with BP reduction.

Adult↗
PubMed1992

[Production of monoclonal antibodies against a wild strain of rabies virus].

Production of monoclonal antibodies against a wild strain of rabies virus. Cell fusion of SP 2/O, a murine myeloma against a wild strain of rabies virus has originated five monoclonal antibodies (M.A.) specific for virus nucleocapsid , one M.A. specific for virus glycoprotein and one M.A. specific for a viral membrane protein.

Animals↗
PubMed1989

[Diagnosis of rabies infection in animals using monoclonal antibodies].

Two monoclonal antibodies (M.A.), specific for viral nucleocapsid, the M.A. D-20 and the M.A. D-43 raised against a fixed strain of rabies virus (C.V.S. 11), have been tested in parallel with a standard antirabies serum (S.A.R.) in diagnosis of animal rabies virus infection. 44 brain imprints from animals which died from rabies were tested by indirect immunofluorescent technique with monoclonal antibodies. Constant correlation has been found between the M.A. D-43 and the S.A.R. in the diagnosis of animal rabies virus infection in all cases studied. For M.A. D-20, concordance of results with S.A.R. was found only in limited number of cases.

Animals↗
PubMedDate not supplied

Dose-related changes in the mechanical properties of the carotid artery in WKY rats and SHR following relaxation of arterial smooth muscle.

Acute converting enzyme inhibition relaxes arterial smooth muscle and increases arterial compliance in several models of animal and human hypertension. However, it is unknown whether the doses needed for the relaxation of large arteries are similar to those inducing arteriolar relaxation and blood pressure (BP) decrease. To answer this question, we used a previously described model of the in situ carotid artery to determine the pressure-volume relationship over a range of transmural pressures from 25 to 200 mm Hg in normotensive rats (WKY) and spontaneously hypertensive rats (SHR). The pressure-volume relation was determined after an acute single oral administration of either a placebo or the converting enzyme inhibitor quinapril given at two different doses (0.3 or 3 mg/kg). At the end of each experiment, the total relaxation of arterial smooth muscle was achieved after a local administration of potassium cyanide (KCN). In the WKY placebo group, from 25 to 100-125 mm Hg transmural pressure, carotid compliance increased and reached a maximum value at 100-125 mm Hg (i.e. close to the operating range of systemic mean BP of the animals), and decreased thereafter. In the SHR placebo group, carotid compliance was significantly lower than in the WKY placebo group for transmural pressure up to 125 mm Hg, and thereafter was equal or even higher; the maximum value of compliance was reached at 125-150 mm Hg transmural pressure, i.e. substantially less than the operating range of the systemic mean BP of the SHR placebo (180 mm Hg).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMedDate not supplied

[Role of vagosympathetic balance in obesity-induced hypertension].

A sympathetic hyperactivity is a common feature in hypertension, type 2 diabetes (T2D), ageing and obesity-induced hypertension. This increase in sympathetic activity may lead to an elevation of arterial rigidity. By contrast, cardiac parasympathetic impairment is observed in these pathologies. Recently we showed in a model of rats with massive obesity (ventromedial hypothalamic lesions) that an enhanced vagal activity may be protective against hypertension. The aim of the present study was to evaluate the influence of an increase in sympathetic activity and a change in vagal activity on arterial rigidity and hypertension in T2D patients. Fourteen hypertensive T2D patients aged 54 +/- 2 years were compared to 22 elderly normotensive subjects (75 +/- 1 years: 11 controls and 11 T2D) and 34 middle aged normotensive subjects (43 +/- 1 years; 17 controls and 17 T2D). Cardiovascular vagosympathetic activity was investigated by spectral analysis of heart rate (HR) and blood pressure (BP) (Finapres) during 6 min at a controlled breathing rate (12 cycles/min). BP and the low frequencies of systolic BP (LF-SBP) were significantly (p<0.01) higher in hypertensive T2D and elderly patients. Pulse pressure (PP) and the high frequencies of HR (HF-HR) were lower in hypertensive T2D patients. PP was positively correlated to LF-SBP (r=0.58; p=0.03) only in hypertensive T2D patients. Diastolic BP was negatively correlated to HF-HR in elderly control subjects (r=-0.63; p=0.03) but not in hypertensive T2D patients. The present results suggest that: sympathetic nervous system activity is enhanced in subjects over 70 years without any aggravating effect of T2D and in middle-aged hypertensive patients with type 2 diabetes; the increase in pulse pressure, an index of arterial rigidity, in elderly subjects may result from sympathetic override; the decrease in the cardiac sympathovagal balance, mainly due to a high vagal activity, may be protective against the occurrence of hypertension in patients with type 2 diabetes.

Age Factors↗