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Biomedical subjects

A Kamoun

Publications and source records attributed to A Kamoun.

At least 19 recordsLinked to original sources
PubMed2006

Protective effect of resveratrol on ethanol-induced lipid peroxidation in rats.

AIM: Chronic ethanol treatment induces an increase in oxidative stress. As polyphenolic compounds are potent antioxidants, we aimed to examine whether dietary supplementation of resveratrol may attenuate lipid peroxidation, the major end-point of oxidative damage resulting from chronic ethanol administration. METHOD: Three groups of male Wistar rats were used. The first group served as control and received a daily intraperitoneal injection of 0.9% saline. The second group of rats was daily injected with 35% ethanol at 3 g/kg body weight. The third group was given the same dose of ethanol and supplemented with resveratrol (5 g/kg) in the standard diet. Malondialdehyde (MDA), an indicator of oxidative stress, was measured in the liver, heart, brain, and testis. RESULTS: At the end of a 6 weeks treatment period, MDA levels were significantly increased by 51.5, 53.7, 72.7, and 40.5% in the liver, heart, brain, and testis, respectively. However, when ethanol treated rats were given resveratrol the increase in MDA levels was significantly reduced in all organs to nearly those of control rats. CONCLUSION: Resveratrol is able to inhibit the ethanol-induced lipid peroxidation and have protective effect against oxidative injury.

Animals↗
PubMed2006

Vasopressin and nitric oxide synthesis after three days of water or food deprivation.

Nitric oxide has been suggested to be involved in the regulation of fluid and nutrient homeostasis. In the present investigation, vasopressin and nitric oxide metabolite (nitrite and nitrate) levels were determined in plasma of male Wistar rats submitted to water or food deprivation for three days. Hematocrit and plasma sodium showed marked increase in dehydrated and starved rats. Potassium levels and plasma volume decreased in both treated groups. Plasma osmolality and vasopressin levels were significantly elevated in water deprived (362.8 +/- 7.1 mOsm/kg H2O, 17.3 +/- 2.7 pg/ml, respectively, p < 0.001) rats, but not in food deprived (339.9 +/- 5.0, 1.34 +/- 0.28) rats, compared to the controls (326.1 +/- 4.1, 1.47 +/- 0.32). The alterations observed in plasma vasopressin levels were related to plasma osmolality rather than plasma volume. Plasma levels of nitrite and nitrate were markedly increased in both water and food deprived rats (respectively, 2.19 +/- 0.29 mg/l and 2.22 +/- 0.17 mg/l versus 1.33 +/- 0.19 mg/l, both p < 0.01). There was a significant negative correlation between plasma nitrite and nitrate concentration and plasma volume. These results suggest that both dehydration and starvation increase plasma nitric oxide, probably by activation of nitric oxide synthases. The release of nitric oxide may participate in the regulation of the alteration in blood flow, fluid and nutrient metabolism caused by water deprivation or starvation.

Animals↗
PubMed2004

Evolution of acquired resistance to third-generation cephalosporins in Enterobacteriaceae in a Tunisian hospital 1993-2001.

Between January 1993 and December 2001, the overall frequency of resistance to third-generation cephalosporins in isolates of Enterobacteriaceae from Charles Nicolle Hospital, Tunis, rose from 2.4% to 7.4%. Klebsiella pneumoniae was the most prevalent species (56%), followed by Escherichia coli (15%) and Proteus mirabilis (9%). A rate of 49% was observed among isolates from paediatric patients in 1999, caused mostly by outbreaks in the neonatal intensive care unit of K. pneumoniae and P. mirabilis isolates that produced extended-spectrum beta-lactamases.

Anti-Bacterial Agents↗
PubMed2001

Two-year surveillance of antibiotic resistance in Streptococcus pneumoniae in four African cities.

Worldwide spread of antibiotic resistance in Streptococcus pneumoniae is a major problem. However, data from West and North African countries are scarce. To study the level of resistance and compare the situations in different cities, a prospective study was conducted in Abidjan (Ivory Coast), Casablanca (Morocco), Dakar (Senegal), and Tunis (Tunisia), from 1996 to 1997. The resistances to eight antibiotics of 375 isolates were studied by E test, and the results were interpreted using the breakpoints recommended by the National Committee for Clinical Laboratory Standards. Overall, 30.4% of the isolates were nonsusceptible to penicillin G (25.6% were intermediate and 4.8% were resistant). Amoxicillin (96.3% were susceptible) and parenteral third-generation cephalosporins (92.7%) were highly active. Resistance to chloramphenicol was detected in 8.6% of the isolates. High levels of resistance were noted for erythromycin (28%), tetracycline (38.3%), and cotrimoxazole (36.4%). Resistance to rifampin was rare (2.1%). There were significant differences in resistance rates between individual countries. Multiple resistance was more frequent in penicillin-nonsusceptible isolates than in penicillin-susceptible isolates. Recommendations for treatment could be generated from these results in each participating country.

Africa↗
PubMed2000

Vasopressin and A1 noradrenaline turnover during food or water deprivation in the rat.

In the present study, we have examined in Wistar rats the effects of food or water deprivation of 3 days on the hypophyso-adrenal axis, vasopressinergic system and activity of A1 noradrenergic brain stem cell group, which is involved in the control of the hypothalamic neuro-endocrine activity. Levels of adrenocorticotropic hormone (ACTH) and vasopressin (AVP) were determined by radio-immunoassay, and corticosterone level was determined by fluorimetric method. Plasma levels of ACTH and corticosterone were greatly increased in both groups of rats. In water-deprived rats, plasma AVP (13.83 +/- 1.63 vs. 3.03 +/- 0.23 pg/ml) and osmolality levels were significantly elevated with a marked decrease of AVP hypophysis content (272 +/- 65 vs. 1098 +/- 75 ng/mg protein), but not in food-deprived rats in which osmolality did not change and AVP remained stocked (2082 +/- 216 ng/mg protein) in the hypophysis without release in the plasma (1.11 +/- 0.23 pg/ml). These observations indicated that both food-deprivation and water-deprivation stimulated the pituitary adrenal axis thereby suggesting a stress state. AVP production is stimulated both by fluid and food restriction but is secreted with differential effects: during food restriction AVP secretion is limited to supporting the hypothalamic pituitary-adrenal system.

Animals↗
PubMed2000

[The effect of age and dehydration on the activity of the vasopressinergic system in rats].

The aim of our work was to study the different blood parameters as well as the activity of the vasopressinergic axis in young and mature male rats under normal conditions and following a 3-day dehydration cycle by water deprivation. Under normal conditions, our study demonstrates higher levels of vasopressin in mature rats as compared to young rats. This could be due in part to the higher blood osmolality in the mature rats. After dehydration, hypovolemia, plasmatic hyperosmolality, hypernatremia and hyperproteinemia cause a stimulation in vasopressin synthesis and release, as seen in results obtained from the hypothalamus, hypophysis and plasma in both young and mature rats. However, the response of the vasopressinergic axis to dehydration is greater in young rats, suggesting a more pronounced sensitivity to osmotic factors.

Aging↗
PubMed2000

[Infectious endocarditis caused by a glycopeptide-resistant enterococus].

Enterococci are an important cause of infective endocarditis. Their resistance to most of the antibiotics involve real therapeutic problems. We report the first clinical isolate of glycopeptide resistant enterococcus from blood culture of patient with a prosthetic valve endocarditis. The strain is an E. faecium with a high level of resistance to vancomycin and teicoplanin (MIC > 256 mg/l), a low level of resistance to gentamycin (MIC = 6 mg/l) and susceptible to ampicillin (MIC = 1.5 mg/l). Therapeutic failure was observed leading to a surgical treatment. Therapy of such infection caused by multiresistant Enterococcus must be based on the study of bactericidal activity of antibiotic associations. In order to control the spread of this emerging resistance, the implementation of control measures is necessary.

Adult↗
PubMed1999

Urolithiasis in Tunisian children: a study of 120 cases based on stone composition.

The composition of urinary stones in children depends on socioeconomic conditions and hygiene, geographical area, and dietary habits. We analyzed urinary stones from 120 consecutive Tunisian children (81 males, 39 females) aged 5 months to 15 years. The stone was located in the upper urinary tract in 91 cases (76%). Stone analysis included both a morphological examination and an infrared analysis of the nucleus and the inner and peripheral layers. The main components of bladder calculi were whewellite (69%) and struvite (22%), whereas the main component of upper urinary tract calculi was whewellite (67%). The nucleus of bladder stones was composed of ammonium urate (45%), struvite (28%), cystine (10%), and carbapatite (7%). The nucleus of kidney and ureteral calculi was mainly composed of ammonium urate (38%), whewellite (24%), carbapatite (13%), or struvite (11%). Based on stone composition, urinary tract infection was involved in the nucleation or growth of a third of calculi. Endemic urolithiasis involving simultaneous nutritional, metabolic, and infectious factors, and defined by its nucleus composed of ammonium urate without struvite, represented 40% of cases. Exclusive metabolic factors - including genetic diseases such as primary hyperoxaluria, cystinuria, and hypercalciuria - were responsible for less than 25% of cases.

Adolescent↗
PubMed1999

Tissue norepinephrine turnover and cardiovascular responses during intermittent dehydration in the rat.

We investigated the central and peripheral sympathetic responses to intermittent dehydration in rats. The norepinephrine (NE) turnover, a biochemical index correlated with noradrenergic neuronal activity, was measured. The modification of blood pressure was also determined by telemetry during the different cycles of dehydration. Dehydration caused a decrease of NE turnover in A2, A5 and A6 nuclei and in peripheral organs. The vasopressinergic level of dehydrated rats decreased in hypophysis and hypothalamus, and increased in plasma. A repeated gradual increase of arterial blood pressure during the first three days of dehydration, followed by a sudden drop when the rats were rehydrated on the fourth day was observed. In conclusion, our study revealed an increase in blood pressure and in central sympathetic activity during dehydration.

Animals↗
PubMed1999

Effects of acute and chronic starvation on central and peripheral noradrenaline turnover, blood pressure and heart rate in the rat.

When faced with stress, an organism calls upon several mechanisms to maintain biological homeostasis. The cardiovascular system is the first to respond usually with an increase in arterial pressure and tachycardia. Therefore we investigated the central and peripheral sympathetic responses to acute and chronic starvation in Wistar rats. The noradrenaline (NA) turnover rate was determined in different catecholaminergic nuclei (A1, A2, A5, A6) as well as the arterial blood pressure and heart rate modifications. During acute starvation (3 days of starvation), the NA turnover was increased in the A1 and rostral A2 nuclei as well as in ventricles and kidneys and decreased in the A6 nucleus. During chronic starvation (4 consecutive cycles of 3 days of starvation plus 1 day of feeding), the NA turnover was increased in the A5 and caudal A2 nuclei as well as in ventricles and atria and decreased in the A1 nucleus and kidneys. The arterial blood pressure revealed a gradual decrease during the first 3 days of fasting but the heart rate was not modified. We conclude that starvation should be considered as an unusual state of stress because of the absence of locus coeruleus response (A6 nucleus) despite its well-defined role in stress reactions. One of the manifestations of these central and peripheral noradrenergic changes is the change in blood pressure during the starvation-feeding cycles.

Animals↗
PubMed1999

[Colonic tuberculosis: an exceptional cause of a massive surgical hemorrhage apropos of a case and review of the literature].

Colonic tuberculosis rarely causes massive bleeding, as a matter of fact less than twenty cases have been reported in medical literature. Resorting to surgery in this context is even more exceptional. We have not found any case operated on in the literature we have consulted. Endoscopy together with histological study of biopsies is the best exam for the diagnosis of this disease. We report the case of a 37 year old male, coronarian, carrying a caecal lesion evocative of tuberculosis at the endoscopic exam, who had an emergency right hemicolectomy for massive bleeding caused by caecal tuberculosis. The surgical indication was dictated by the abundance and the persistence of the bleeding. The post-operative course was uneventful.

Adult↗
PubMed1999

[Effect of fasting on glycemia and proteinemia in young and adult rats].

The aim of Our work has consisted of studying the effects of a severe three-day fast on the evolution of the body weight, on glycemia and on proteinemia among the young and mature male rats. The decrease in body weight which is more marked among young rats after starvation shows that the loss of body mass due to fasting decreases with the age of the rats. The physiological perturbations of nutritive constants that have been recorded during this period of fast show that the mature rat first attacks its non-protein stocks or glucides, which leads to a decrease in its glycemia and in its lipids; whereas the young rat uses its proteins after only three days of starvation because of its small stock of lipids.

Age Factors↗
PubMed1998

[Adrenal cortex activity in the malnourished newborn rat].

Newborn rats (4 day-old) were subjected to chronic malnutrition through their mothers submitted to an intermittent fasting (one day out of two) during 41 days. These offspring were compared with others undergoing a treatment of a 21 days malnutrition followed by 20 days ad libitum realimentation. Rats whose mothers were nourished ad libitum with a standard diet served as controls. The body growth was hindered by the malnutrition but restored when fasting was followed by realimentation. The weight of the encephalon, the heart and the ovary was unchanged. In contrast, testicle atrophy was observed without correction by realimentation. A corticoadrenal activation characterized by an increase in blood and adrenal corticosterone levels and by an adrenal gland hypertrophy was observed in undernourished animals. A lower response of the adrenal cortex to ether stress (added stress) was also observed. All these perturbations were suppressed when fasting was followed by refeeding.

Adrenal Cortex↗
PubMed1997

[Urinary calculi in children: contribution of anamnesis, biological exploration and physical analysis of calculi to the etiological diagnosis].

BACKGROUND: It is always of importance to define the cause of urinary calculi disease in children to prevent recurrence and possible impairing of renal function. Nevertheless, etiology is not always easy to prove and must be deduced from both clinical and biological arguments. PATIENTS AND METHODS: The aim of this prospective study including 39 Tunisian children with urinary stones was to identify etiology and stone risk factors and detail the part of clinical and biological data and results of physical analysis of stones in determining the cause of the stone. RESULTS: In 31 cases among 39, clinical and biological data were not sufficient to identify clearly the stone etiology. When considering the structure and stone composition, the cause of the stone could be determined in 97.4% of the cases. An inherited disease was found responsible for the stone in 11 children, urinary tract infection in 13 cases, idiopathic hypercalciuria in nine cases and a nutritional deficiency disease in seven cases. In one case, polycystic kidney disease with metabolic risk factors could explain the stone process. No precise etiology was found in one case. Among infection stones, struvite stones could be related to urea-splitting bacteria while other calculi, containing whitlockite and protein matrix could be related to other micro-organisms. Earlier severe chronic diarrhoea episodes were noted in six among seven children presenting stones with a nucleus mainly composed of ammonium urate. CONCLUSION: Clinical data, biological data from both urine and blood of the patients and also the structure and composition of the stones are needed to identify the cause of urinary calculi. Such a procedure could provide the stone etiology in most cases.

Adolescent↗
PubMed1997

[Effects of simulated weightlessness on the hypophyseal-cortical-adrenal axis in the pregnant rat].

The eventual part of stress in the hormonal responses to simulated weightlessness was studied during gestation in the rat. We have compared these responses with the effects of two other situations well-known to provoke stress: ultrasounds and denutrition. An increase of blood and adrenal corticosterone levels was found in mothers after denutrition, neither after ultrasounds nor after simulated weightlessness. In foetuses, a decrease of weight was noted after denutrition and simulated weightlessness. Foetal suprarenal corticosterone remained normal when mothers were submitted to simulated weightlessness. In this group, a decrease in foetal weight was found that could be explained by non suprarenal hormonal factors or by circulation disturbances.

Animals↗
PubMed1997

[Sequential and ultrastructural study of lactotroph response to stress in rats as a function of age].

In adult rats, ether inhalation stress stimulated basal serum prolactin (PRL) significantly, within a maximum delay of one minute. The same pattern was seen with immature animals of 15-20 and 30 days of age. In contrast, in 2 or 6 days old neonates, serum PRL concentrations remained unaffected by stress. This lack of responsiveness suggests the existence of a transient impairment of lactotroph hormones to stressful stimuli during postnatal life. This hypothesis has been controlled by ultrastructural exploration of lactotrophs. The distribution of organites and secretion grains in lactotrophs was similar in unstressed neonates and adult rats, but after ether stress, the distribution of secretion grains became different with age. Adult lactotrophs showed a peripheral secretion grains aspects indicating cells discharge. In the very young rats, the grains were distributed in the totality of the cytoplasm. These results confirm the existence, in the lactotrophs, of a refractory period to stress in the neonate rats.

Aging↗