Biomedical subjects

N Zeghal

Publications and source records attributed to N Zeghal.

8 recordsLinked to original sources

PubMed2005

Dimethoate effects on thyroid function in suckling rats.

The aim of our work is to study dimethoate effects on thyroid function given in drinking water (40 mg/kg body weight, equivalent to 0.2 g/L) to mothers from day zero until the 10th day after delivery. Pups and their mothers were sacrificed on day ten after parturition. Compared to a control group, dimethoate-treated pups showed a 48% decrease in body weight which could be attributed to a defect in thyroid hormones. Indeed, after treatment by dimethoate, plasma rates of free T4 and T3 decreased by 56% and 40% in the young and by 27% and 15% in dams respectively. We can attribute the reduction in plasma thyroxine and triiodothyronine rates to a decrease in thyroid iodine levels (-75%) in the young and (-24%) in their mothers. The decrease in production of thyroid hormones after dimethoate treatment affect thyroid stimulating hormone (TSH) levels. In fact, plasma TSH levels were multiplied in dimethoate-treated group by factors of 2.31 in dams and 1.96 in their offspring. These biochemical modifications confirmed the histological thyroid aspects of pups and dams. In fact, in dimethoate-treated rats, some thyroid follicles of pups presented vesicular cavities without colloid; others contained colloid. However in dams, thyroid follicles presented cubical epithelial cells which surrounded empty vesicular cavities.

Animals↗

PubMed2004

[Induction and reversibility of thyroid proliferative changes in suckling rats given thiocyanate].

Potassium thiocyanate given in the drinking water of pregnant rats led to decreased body weight in their 14-day-old offspring (27%) without altering thyroid weight. Reduction of the suckling rat's body weight could be explained be defective thyroxinemia (38). Plasma FT3 and TSH were unchanged after thiocyanate treatment. The biochemical changes were in agreement with the histological aspects of the hypothyroid animals. The typical pattern was hyperplastic goiter. Colloid volume was reduced compared with controls. Presence of resorbed peripheral vacuoles, a sign of thyroid hyperactivity, was disclosed by a three-fold increase in radioiodide (131I) uptake compared with controls. When the antithyroid drug was removed from the mother's milk, the pups'weight increased but did not reach control values. Plasma thyroid hormone levels returned to normal and even exceeded control values in spite of partial recovery of thyroid iodine content when thiocyanate treatment was stopped for ten days.

Animals↗

PubMed2003

[Thiocyanate and central nervous system maturation of young mice].

Potassium thiocyanate, given to the drink of pregnant mothers provoked a body weight decrease of 14 day-old mice (-18%), without perturbations of cerebrum and cerebellum weights. The reduction of pups' body weight could be explained by a decrease of plasmatic thyroid hormone levels: FT3 and FT4, (-54; -57%) in youngs and (-66; -49%) in their mothers. A defect of thyroid hormone levels, observed in young mice, provoked a decrease of cerebrum and cerebellum protein concentrations (-15 and -13%) respectively. Modifications of biochemical parameters confirmed the histological aspects of hypothyroid mice cerebellum with purkinje cells incompletely differentiated. When thiocyanate ion was removed from mothers' drink, we have noted in pups a partial return of some biochemical parameters (iodine thyroid contents, protein concentrations of cerebrum and cerebellum) and of cerebellum histological aspects. While thyroxinemia (FT4) and plasmatic FT3 levels were completely restored and even exceeded control values, which were necessary for central nervous system maturity of young.

Animals↗

PubMed2001

[Non-pharmacologic treatment of atrial fibrillation].

Curative non pharmacological treatment of AF includes MAZA anti arrhythmic surgery and ist different variants which are reserved to AF associated with mitral valve disease. Radiofrequency (RF) ablation of AF creating lesions mimicking the MAZE procedure is another curative treatment but its numerous complications lead to put it in stand-by. Focal AF radiofrequency ablation is the only curative method that has encouraging results. The development of the internal cardioversion led to the development of the implantable atrial defibrillator. In spite of the low energy used, the internal shocks are often painful and not well tolerated conducting to stop the use of these devices. Prophylactic atrial pacing among patients with interatrial conduction delay is well established by dual site pacing pioneers. After several attempts to restore sinus rhythm and the fail of drug therapy to reduce heart rate, the latest solution to prevent tachycardiomyopathy is the atrio-ventricular (AV) node modulation or ablation using RF energy.

Atrial Fibrillation↗

PubMed2001

[Propythiouracil and perchlorate effects on thyroid function in young and lactating mice].

We have studied the effects of propythiouracil (PTU) or perchlorate (CIO(4)(-)), given to the mothers' drink from the 15(th) day of pregnancy until the day of sacrifice, on thyroid function of suckling mice. Antihyroid drugs (PTU or CIO(4)(-)) provoked growth perturbations of young mice during studied ages from 6 to 18 days. A decrease of body weight was respectively as follows: 14 and 22% in 6 day-old mice; 16 and 23% in 10 day-old mice; 18 and 18% in 14 day-old mice; 19 and 11% in 18 day-old mice. We have noticed an hypertrophy of thyroid glands of pups and their mothers caused by an increase of pituitary TSH. Thyroid follicles presented the aspect of hypothyroid animals with an increase of follicular number and vascularisation. Structural modifications confirmed biochemical results. In fact thyroid iodine contents decreased strongly in young as follow: 40 and 43% in 6 day-old mice; 51 and 50% in 10 day-old mice; 66 and 84% in 14 day-old mice; 54 and 89% at 18 day-old mice and in their mothers (50, 37%; 59, 54%; 75, 65% and 85, 72%) respectively after PTU or CIO(4)(-) treatment. A decrease of iodine thyroid gland was accompanied by an important fall of free thyroid hormones levels (FT3 and FT4) in young and adult mice. A decrease of thyroid hormonemia could explain the pups' growth perturbations.

Aging↗

PubMed1995

[Analysis of iodine compounds in young rat skin in the period of suckling and in the adult. Effect of perchlorate].

In the suckling and adult rats equilibrated or no by 125I, cutaneous iodine analysed by dialysis and chromatography techniques (Dowex and Sephadex) was the purpose of this study. Dialysis studies had shown that most of steady or labelled skin iodine had an iodide form (90 to 95% of the total iodine). There were at least two intracellular iodide pools: the first one was quickly dialysable, in fact about 60 percent of initial radioactivity represented the intracellular iodide equilibrated with extracellular fluid. The other one wasn't or was little dialysable representing probably the cutaneous iodide storage compartment. Chromatography studies (Dowex or Sephadex) demonstrated that the skin of the young and adult rat contained T4 and T3 hormones in a small percentage. The iodide represented a value more than 90% of initial total radioactivity. Results concerning kinetic skin iodine, eight and twenty four hours after LT4(125)I injected to adults and to control and iodine deficient ten day old rats, confirmed those obtained here by Dowex chromatography and previous ones. Triiodothyronine (T3) might have an origin either in thyroid synthesis or in deiodination of T4. Consequently we may say that the skin of the 10 day and 14 day old rats presented a great accumulation of iodide. The perchlorate inhibited this storage. Indeed, in young deficient iodine rats at birth, cutaneous iodide concentrations were reduced whereas those of T4 and T3 as well as the ratio T3/T4 haven't been modified. Therefore the iodine deficiency seemed to have a few effects on the skin deiodinating activity. Indeed the skin of iodine deficient immature rat became unable to accumulate iodide. The main effect of the skin iodine deficiency was the inhibition of iodide transport from the extracellular fluid to the intracellular one, but not inside cellular structures.

Animals↗

PubMed1992

Iodide and T4 kinetics in plasma, thyroid gland and skin of 10-day-old rats: effects of iodine deficiency.

The effects of iodine deficiency on the peripheral metabolism of thyroid hormone in immature rat were evaluated by measuring the kinetics of iodide and thyroxine (T4) in control and iodine-deficient 10-day-old rats. Iodine-deficient pups were obtained by giving the mother drinking water containing perchlorate; this anion is not transferred but prevents iodine transfer in the mother's milk. Labelled iodocompounds were measured in plasma, thyroid and skin for 48 h following intravenous injection of Na131I plus [125I]T4. Data were interpreted by compartmental analysis. The iodide plasma clearance rate, plasma equivalent distribution volume, plasma concentration, production and iodine thyroid content of iodine-deficient rats were significantly lower (-29%, -31%, -84%, -89% and -87% respectively) than in control 10-day-old rats. The iodide thyroid uptake was reduced (-47%) but remained higher than the release of iodine as T4. Cutaneous iodine was lost much more quickly by iodine-deficient pups than by control pups, explaining the decreased iodide distribution volume. The parameters of T4 metabolism were not changed by iodine deficiency, except for a slight but significant reduction of the thyroxinemia and T4 pools (-13%). Thence, T4 production was not significantly changed (about 8 pmol/h in control and iodine-deficient rats). The labelled T4 curves in iodine-deficient and control skin were superimposed and the patterns of labelled T3 derived from [125I]T4 were identical. Thus, the skin of immature rats converts T4 to T3; this process was not disturbed by iodine deficiency. The thyroid function of immature rats is particularly resistant to iodine deficiency, but the mechanisms remain unknown.

Animals↗

PubMed1975

Adrenal catecholamines content in fetal and newborn rats.

The adrenal epinephrine content of newborn rats delivered by caesarian section on day 21.5 of gestation and maintained at thermal neutrality (37 degrees C) did not decrease over the 6 h following birth in spite of a transient phase of hypoglycemia. Cold exposure (30 or 24 degrees C) of the newborn rats immediately after birth did not decrease their adrenal epinephrine content. A decrease in adrenal epinephrine content is observed in 21.5-day-old rat fetuses after insulin-induced hypoglycemia for 4 h, after 2-deoxy-D-glucose injection or after anoxia. In 20.5-day-old rat fetuses, insulin-induced hypoglycemia for 4 h or 2-deoxy-D-glucose did not decrease the adrenal epinephrine content of the fetus. No variation was observed in norepinephrine content of the adrenal gland in all these situations. It is concluded that spontaneously occurring hypoglycemia or cold exposure are not sufficient stimuli to induce adrenal epinephrine depletion. It is suggested that hypoxia is perhaps the physiological stimulus for epinephrine secretion in newborn rats.

Adrenal Glands↗