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D Garnier

Publications and source records attributed to D Garnier.

At least 19 recordsLinked to original sources
PubMed2004

Nutritional status, growth and sleep habits among Senegalese adolescent girls.

OBJECTIVE: To study the relation between sleep habits, nutritional status, growth and maturation in a group of African adolescent girls. The main hypothesis to be tested was that sleep length could be an effective way to spare energy, and thus malnourished girls sleep longer than normal girls. DESIGN: Three repeated yearly surveys (1997-1999) on a subsample of girls drawn from a larger study cohort on growth at adolescence. SETTING: The Niakhar district in the central part of Senegal. SUBJECT: In total, 40 girls were initially drawn. Missing girls were replaced at each round by girls having the same characteristics and belonging to the same cohort. INTERVENTION: At each round, data on pubertal development (breast stages and occurrence of menarche), growth and nutritional status were collected. Adolescents wore an accelerometer for three or four consecutive nights and days at each round. RESULTS: At the beginning of the survey, girls were 13.3+/-0.5 y old. They were under international reference values in weight and height. Their mean sleep duration was 8.5+/-0.9 h. Their puberty status did not influence their sleep habits; however, they slept more in March than in June, which was related to the seasonal change in daylight. There was a significant relation between body mass index and sleep habits: thinner girls slept a longer time and more quietly than the more corpulent girls. CONCLUSION: The nutritional status of these girls influenced their sleep habits: this may have been either a direct causal relation or a consequence of a protective attitude on the part of the mothers towards the frailer girls.

Adolescent↗
PubMed2003

[Arterial complications of thoracic outlet syndrome and pseudarthrosis of the clavicle: three patients].

During a 3-year period, three patients developed arterial complications related to congenital or post-traumatic old pseudarthrosis of the clavicle. Arterial complications of pseudarthrosis of the clavicle presenting as a thoracic outlet syndrome are very rare. Symptoms are variable and occur late. Without treatment, the prognosis is poor with spontaneous development of gangrene. Arterial morphology investigations should be undertaken in patients with pseudarthrosis of the clavicle or isolated arterial symptoms involving the upper limb whose radial pulse disappears during postural tests. Duplex Doppler of the subclavian artery is an excellent screening exam but selective arteriography is the gold standard. It shows proximal arterial lesions (embolytic stenosis of the subclavian artery with post-stenotic dilatation), as well as distal embolic complications. Both static and postural tests must be performed to unmask subclavian restriction by the clavicle, proving its causal effect in the arterial complications. There are four clinical varieties: chronic thrombosis of the subclavian artery, distal arterial micro emboli, acute thrombosis of proximal arteries of the upper limb, and subclavian aneurysm. These lesions are thought to be due to chronic constriction and repeated arterial microtrauma. Congenital or post-traumatic pseudarthrosis, hypertrophic callus, arterial restriction by a screw in a clavicular plate, usually explain the arterial lesions. Bone tumors and Paget's disease are potential but exceptional clavicular etiologies. Surgical treatment is always necessary. Clavicular resection is usually needed in case of pseudarthrosis; there is no functional handicap. Plate fixation and autologous grafting, or open reduction and internal fixation are other valid surgical treatments; The embolytic lesions must be treated to prevent recurrence of distal embolization: graft resection and thromboendarteriectomy have been described. Neurological and venous decompression may be associated at the same time. Complementary treatment can be associated: distal bypass, cervicothoracic sympathectomy, in situ thrombolysis or thrombectomy. Endovascular treatment is not indicated. Optimal treatment of clavicular fractures is required to prevent the development of thoracic outlet syndrome.

Aged↗
PubMed2003

[Influence of urban migration on physical activity, nutritional status and growth of Senegalese adolescents of rural origin].

In Africa, rural populations especially adolescent girls resort to urban migrations for labour in order to diversify and improve their livelihood. Their work and their living conditions may influence their health and development patterns. The aim of this study was to evaluate the influence of these migrations on physical activity, nutritional and growth status of rural Senegalese adolescent girls. In 1998, within the framework of a longitudinal study of growth during puberty (n = 406), a sub-sample (n = 80, 14.4 +/- 0.5 years) was drawn in order to estimate physical activity, during three days, quantitatively by accelerometry and qualitatively by questionnaire. One part of this sample temporarily migrated to Dakar in order to work as maids (migrants, n = 40). The other part remained in the rural community of Niakhar in order to help their families in daily domestic and agricultural tasks and/or to attend school (non-migrants, n = 40). In 1999, sexual maturation of 331 adolescent girls (15.5 +/- 0.5 years) belonging to this group was based on stages of breast development and occurrence of menarche. Their growth and nutritional status were assessed with anthropometry (height, weight, mid arm circumference, six skinfolds). Adolescents were asked about their urban migratory histories and were divided into four categories according to the duration of urban migration: no migration (NM), short (S), medium (M) and long duration (L). These adolescent girls had a very high physical activity which is far higher than that of American girls. Migrants were more active than non-migrants (p < 0.0001). In 1999, as a whole, these 331 adolescent girls were smaller, thinner and less mature than adolescent girls from industrialized countries. Midarm circumference, body mass index (BMI) and fat mass index (FMI) were significantly higher with the duration of migration (p < 0.01), after adjusting for differences in sexual maturation. Growth retardation seemed more important for the adolescent girls who never migrated and for those who have the longest duration of migration (p = 0.05). At the beginning of puberty, there were no differences in height for age indice and BMI. Urban migrations resulted in an advanced puberty and an improvement of nutritional status (higher BMI, FMI and midarm circumference) but without catch-up in growth. These findings could be explained by precarious living conditions in rural area and by higher workload in urban area.

Adolescent↗
PubMed2001

Assessment of physical activity among rural Senegalese adolescent girls: influence of age, sexual maturation, and body composition.

PURPOSE: To analyze the level of habitual physical activity and its relationship with age, maturational stage, and growth status in a group of adolescent Senegalese girls. METHODS: Physical activity was assessed for 3 consecutive years in a sample of 40 girls of rural origin. They were 13.3 +/- 0.5 years old at the beginning of the study and belonged to a Sereer community located in the center of Senegal. Minute-by-minute movement counts using accelerometers enabled quantification of levels of physical activity. The assessment was performed during a 4-day period in the first round (1997) and during a 3-day period in 1998 and 1999. Half of the girls were not yet pubescent during the first round, and the whole sample displayed growth retardation in weight and stature, compared with the World Health Organization/National Center for Health Statistics reference. RESULTS: Estimated levels of activity were high, ranging from 1.80 to 1.85 multiples of basal metabolic rate. There was a clear decline in the activity level during the course of study. Schoolgirls were less active than the others. Mature adolescents showed more activity during the night. A weak, but significant and positive correlation existed between body mass index and activity during the day; during the night, there was a positive correlation with fat and lean body mass. CONCLUSION: Factors determining the activity level were intricate but greater maturity and better nutritional status appeared to be positively related to the activity level.

Adolescent↗
PubMed2001

Relationship between stunting in infancy and growth and fat distribution during adolescence in Senegalese girls.

OBJECTIVE: To study the long-term impact of stunting during infancy on maturation, growth and fat distribution in adolescence. DESIGN: A cohort of 406 Senegalese adolescent girls of rural origin underwent clinical and growth assessments every year from 1995 to 1999. SUBJECTS: Mean coverage rate was 82% at each round. Adolescent girls were 11.4+/-0.5 y of age in 1995 and 15.5+/-0.5 y of age in 1999. Their growth status during infancy was known. About 20% of the girls had a height-age (H-age) below -2 Z-scores (chronic malnutrition or stunting) when they were 6-18 months of age. As adolescents, the girls were divided into two groups on the basis of H-age: those stunted and those non-stunted during infancy. MEASUREMENTS: Sexual maturation was assessed by stage of breast development and menarche. Height, body mass, sitting height, bi-iliac and bi-acromial diameters, and six skinfolds were measured. RESULTS: Differences in sexual maturation between previously stunted and non-stunted girls were not significant. Girls stunted at infancy caught up in body weight and subcutaneous fat mass during puberty, but they did not catch up on stature, sitting height or skeletal breadths (bi-acromial and bi-iliac diameters) until the final observation in 1999. Stunted girls did not have less subcutaneous fat (sum of six skinfolds) or a lower BMI. Regional variation in subcutaneous fat distribution (Z-score profile) indicated greater accretion at the biceps and subscapular sites in stunted compared to the non-stunted girls. Regional fat distribution was also assessed by principal component analysis (PCA) performed on the residuals of the six skinfolds measured during the final round (1999). PCA identified three components. Stunted and non-stunted girls were similar for the first (trunk-extremity contrast) and second (anterior-posterior contrast) components. However, there was a difference for the third component: stunted girls tended to accumulate more subcutaneous fat on the upper part of the body (trunk or arms) than non-stunted girls. CONCLUSION: Stunted Senegalese girls have a potential for catching up in growth during puberty. The greater accumulation of subcutaneous fat on the upper body in stunted girls may be a consequence of complex hormonal adjustments at the onset of puberty.

Adipose Tissue↗
PubMed2000

Source, catabolism and role of the tetrapeptide N-acetyl-ser-asp-lys-Pro within the testis.

The tetrapeptide N-Acetyl-Seryl-Aspartyl-Lysyl-Proline (AcSDKP) is a natural regulator of hematopoietic stem cell proliferation. The present study was aimed at investigating the presence and the role of AcSDKP in rat testis. Specific immunoreactivity was always observed in the interstitial tissue at all stages of testicular development and in elongated spermatids at 45 days of age and in adults. In accordance with the interstitial labeling, high AcSDKP levels were detected in Leydig cell and testicular macrophage culture media and cell extracts, as well as in the testicular interstitial fluid (TIF). Much lower concentrations were found in peritubular cells and Sertoli cells cultures, whereas very low concentrations were present in cultured spermatocytes and spermatids. In contrast to the slight degradation rate of AcSDKP observed in the spermatocyte and spermatid culture media, no catabolism of the peptide was seen in testicular somatic cell culture medium. Furthermore, the degradation rate of AcSDKP was much lower in TIF than in peripheral blood plasma. Despite the very strong evidence indicating that Leydig cells and testicular macrophages produce AcSDKP, the selective destruction of these cells did not result in any change in AcSDKP levels in TIF or in plasma. This suggests a compensatory mechanism ensuring constant levels of the peptide in TIF when interstitial cells are absent. Finally, in vitro, in the presence of AcSDKP, significantly more [(3)H]thymidine incorporation was found in A spermatogonia. In conclusion, this study establishes the presence of very high concentrations of AcSDKP in rat testis and demonstrates its Leydig cell and testicular macrophage origin. The presence of AcSDKP in the TIF and its stimulatory effect on thymidine incorporation in spermatogonia very strongly suggest its implication in the paracrine control of spermatogenesis.

Animals↗
PubMed1999

Length modulation of active force in rat cardiac myocytes: is titin the sensor?

The intrinsic cellular mechanisms by which length regulates myocardial contraction, the basis of the Frank-Starling relation, are uncertain. The aim of this work was to test the hypothesis that passive force, possibly via titin, participates in the modulation of Ca2+ sensitivity of cardiac contractile proteins induced by stretch. Titin degradation by a mild trypsin digestion modulated passive force induced by increasing from 1.9 to 2.3 microm sarcomere length in skinned rat cardiac cells. Force-pCa curves were established at these two sarcomere lengths after various durations of trypsin application that induced different passive force levels. They allowed us to evaluate myofilament Ca2+ sensitivity by the pCa of half-maximal activation (pCa50). In control conditions, stretching cells from 1.9 to 2.3 microm induced a leftward shift of pCa50 (DeltapCa50) of 0.39+/-0.03 pCa units (mean+/-SEM, n=8 cells), reflecting an increase in Ca2+ sensitivity of the contractile machinery. Passive force measured every 2 min decreased exponentially after the beginning of the trypsin application (t1/2 approximately 12 min). The first 30% decrease of passive force did not affect the stretch-induced variation in Ca2+ sensitivity. Then, with further decrease in passive force, DeltapCa50 decreased. At the lowest passive force investigated 20% of initial passive force, DeltapCa50 decreased by approximately 55%. These effects were not accompanied by a significant modification of either maximal activated force at pCa 4.5 solution or pCa50 at 1.9 microm sarcomere length. This indicates that there was no major functional alteration of the contractile machinery during the protocol as also suggested by contractile and regulatory protein electrophoresis on 2.5-12% gradient and 15% SDS-PAGE gels. Thus, besides modulation induced by the reduced lattice spacing during enhanced heart refilling, Ca2+ sensitivity of the cardiac contractile machinery may be controlled at least partially by internal passive load, which is known to be largely attributable to titin.

Actin Cytoskeleton↗
PubMed1998

Severe and early alteration of action potential during acute cardiac rejection in rats.

INTRODUCTION: Alteration of cardiac action potential and its adaptation to heart rate could contribute to cardiac dysfunction and arrhythmias during acute cardiac rejection. METHODS AND RESULTS: Heterotopic heart transplantation was performed in allogeneic and syngeneic rats in which the action potentials of right and left ventricles were measured at 1, 2.5, 3.3, and 5.7 Hz successively using standard microelectrode techniques and compared with nontransplanted hearts. For each frequency, we measured action potential amplitude, action potential duration, transmembrane resting potential, and Vmax. In the right ventricle, at 1 Hz in the presence of rejection (n = 40), a significant increase was observed in action potential duration at 20%, 50%, and 70% repolarization (82.5%, 75.6%, and 70.8%, respectively) and in action potential amplitude (+17.9 mV), and the resting potential was decreased (-5.3 mV). A lack of adaptation of action potential duration to the driving frequency was observed in the rejecting heart group in contrast to controls (n = 20) and nonrejecting hearts (n = 13). Similar results were observed in the left ventricle and surprisingly in the native hearts (n = 11) of recipients with allografted rejecting hearts in the abdominal position. CONCLUSION: Action potential and its adaptation to the driving frequency is considerably altered during acute rejection. A humoral factor could contribute to cardiac dysfunction.

Action Potentials↗
PubMed1997

Resting tension participates in the modulation of active tension in isolated guinea pig ventricular myocytes.

We studied active and passive properties of intact isolated guinea-pig ventricular myocytes in auxotonic conditions. Cells were attached using carbon fibres. The passive properties of the myocytes, in the presence of the stretch-activated channel blocker streptomycin sulphate, could be separated into two groups: stiff cells (stiffness slope = 2.88 +/- 0.93 nN/micron3, n = 63 cells) and compliant cells (stiffness slope = 0.91 +/- 0.35 nN/micron3, n = 52 cells). The study and the localization of the different kind of cells indicated that endocardium is mainly constituted of stiff cells (80%) while the epicardium contained more compliant cells (60%). When a longitudinal strain was applied to compliant cells, an increase in resting tension, diastolic sarcomere length and active tension were observed. On the other hand, in stiff cells, it induced an increase in resting tension and active tension with little change of diastolic sarcomere length. In both kinds of cells, strain had no effect on Ca2+ transient amplitude and shape. Plotting active tension v diastolic sarcomere length also clearly showed two separated populations of cells, corresponding to stiff and compliant cells. The results of the two groups of cells when plotting active tension v resting tension could not be distinguished. We conclude that resting tension is an important factor in the modulation of active tension by stretch in addition to interfilament lattice spacing or sarcomere length.

Animals↗
PubMed1996

Orthophosphate salts induce calcium current recovery from blockade by gadolinium in isolated guinea-pig ventricular myocytes.

Using the whole-cell configuration of the patch-clamp technique, we studied the incomplete recovery of the high voltage-activated calcium current (ICa,L) from a complete blockade by 10 microM gadolinium. The study was performed on isolated guinea-pig ventricular myocytes. ICa,L recovery depended on the duration of application of Gd3+: for a mean application time of 1.63 +/- 0.45 min, a recovery to 67 +/- 22% of the initial current amplitude (n = 12 cells) was observed; when the application lasted 5.1 +/- 1.2 min ICa,L recovered to 27 +/- 13% (n = 14 cells). The partial recovery of ICa,L was accompanied by a slowing of the inactivation phase of the current. IF, during the incomplete recovery, cells were exposed to a solution containing 330 microM of an orthophosphate salt, such as NaH2PO4 or KH2PO4, the current amplitude increased to 80 +/- 13% of the initial current (n = 10 cells) in a reversible manner. However, the slowing of the inactivation phase was maintained. Our results show that the partial recovery of ICa,L from blockade by gadolinium is due to an interaction of the blocker with an extracellular part of the channel, possibly one involved in voltage-dependent inactivation.

Animals↗
PubMed1996

Detection of acute cardiac allograft rejection with high resolution electrocardiography: experimental study in rats.

BACKGROUND AND METHODS: To diagnose early acute cardiac rejection, we evaluated high-resolution electrocardiography in rats. Heterotopic heart transplantations were performed in allogeneic animals, either treated with cyclosporine or untreated, and in syngeneic animals. High-amplification electrocardiograms were recorded daily, under anesthesia, with two intra-abdominal leads. After amplification (x 5000 to 20,000), the electrocardiographic signal was acquired and analyzed with P-Clamp software. We measured the amplitude (millivolts) and duration (milliseconds) of the auriculogram (P wave) and the ventriculogram (QRS wave), the duration of auriculoventricular conduction (milliseconds; PQ interval) and the heart rate. Twenty-five grafted hearts were fully studied in recipients not treated with cyclosporine (allogeneic n = 16, syngeneic n = 9). RESULTS: In the allogeneic group, acute cardiac rejection was always accompanied by an early and progressive increase in P wave duration and PQ interval, whereas an increase in QRS duration was subsequently recorded. No significant change in P wave, PQ interval, or QRS wave duration was recorded in the syngeneic group, which showed no histologic rejection lesions. A decrease in P wave and QRS wave amplitude was recorded in both groups of animals. In the allogeneic group treated with cyclosporine (n = 21), grafted hearts were removed early (4.5 +/- 0.5 days): 10 cardiac grafts were rejected and 11 were not. An increase in P wave duration > or = 20% was associated with mild rejection in most cases. The sensitivity and specificity of this electrocardiographic sign were excellent (100%). The auricular (right and left atria) and the ventricular (right and left ventricles) tissues were evaluated histologically. In the allogeneic groups (n = 26), the histologic lesions during acute rejection were greater in the auricular myocardium than in the ventricular myocardium. Rejection in the atrial and ventricular myocardium was most often differentiated by one degree according to the Billingham classification. CONCLUSIONS: We concluded that acute cardiac rejection in rats is associated with early conduction disturbances in the atrial myocardium which can be shown by high-resolution electrocardiography.

Abdomen↗
PubMed1995

Prevention of thromboses in human patients with Bothrops lanceolatus envenoming in Martinique: failure of anticoagulants and efficacy of a monospecific antivenom. Research Group on Snake Bites in Martinique.

Envenomation by the Bothrops lanceolatus, a snake found only in Martinique, leads to swelling and pain, and occasionally to systemic signs and/or coagulopathy. Severe thromboses at some distance from the site of the bite may appear within 48 hr. Uncertainties as to the actual development of thrombotic complications in patients appearing to be suffering from moderate poisoning and as to the availability and the toxicity of a monospecific antivenom (AVS) initially led us to reserve antivenom for the most severe cases, and to use anticoagulants to prevent thromboses in all patients. This approach was modified after we observed serious thromboses in patients with moderate poisoning. Of 50 adult snake bite cases hospitalized between June 1991 and August 1994, 11 developed serious thrombotic complications at 36 /+- 27 hr (mean +/- SD) (range 12-96) following envenomation, despite early preventive anticoagulant therapy. Those included pulmonary embolism (two cases), cerebral infarction (six cases), myocardial infarction (one case), and cerebral and myocardial infarctions (two cases). Sixteen patients were not treated with AVS: 10 of these recovered without complications and six developed systemic thrombosis causing permanent disability in three cases. Thirty were treated with an intravenous infusion of 2-6 vials of AVS given 2-48 hr after the bite. Of these, three died of cerebral infarction that developed before the initiation of serotherapy. All others recovered. Among patients treated with AVS, three presented with mild anaphylactic reactions, while one developed serum sickness that responded to steroids. These data indicate that preventive anticoagulant therapy is of limited efficacy in Martinique.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1994

The stretch-activated ion channel blocker gadolinium also blocks L-type calcium channels in isolated ventricular myocytes of the guinea-pig.

We show that gadolinium (Gd3+) is a potent calcium channel blocker in guinea-pig isolated ventricular myocytes. A dose-dependent inhibition of ICaL was found with an EC50 of 1.4 microM and a complete inhibition at 10 microM Gd3+. When compared with Cd2+, it appeared that the blockade of ICaL is a complex phenomenon probably involving more than one site of interaction (a Hill coefficient of 1.6 was found for Gd3+ vs. 1.0 for Cd2+). It is concluded that Gd3+ ions completely block ICaL at concentrations used to block stretch-activated channels (SAC), rendering its use as a specific SAC inhibitor problematic.

Animals↗
PubMed1994

Streptomycin reverses a large stretch induced increases in [Ca2+]i in isolated guinea pig ventricular myocytes.

OBJECTIVE: The aim was to test the hypothesis that in single guinea pig ventricular myocytes a large stretch induced increase in resting calcium was sensitive to the mechanosensitive channel blocker streptomycin. METHODS: Carbon fibres were used to stretch cells loaded with the fluorescent calcium indicator indo-1. Force, sarcomere length, and internal calcium activity ([Ca2+]i) were measured. RESULTS: In approximately 60% of the cells studied, a stretch which increased sarcomere length by approximately 6% caused a large increase in [Ca2+]i (up to 60% of the size of a [Ca2+]i transient at 0.25 Hz). When a mixture of antibiotics (streptomycin-penicillin) was used in solutions to isolate and store cells, this phenomenon was never observed (n = 19 cells). Direct application of physiological saline solution (PSS) could not reverse the increase in [Ca2+]i within 60 s of application (n = 7 cells). Direct application of penicillin [1000 IU per 50 ml (40 microM)] reversed the increase in [Ca2+]i within 60 s of application in only 3/7 cells. In contrast direct application of the aminoglycoside antibiotic streptomycin (40 microM) rapidly reversed the large increase in [Ca2+]i induced by stretch in each of 13 cells [within 18(SD 10) s of application]. Acute application of 40 microM streptomycin did not modify L-type Ca2+ currents measured under whole cell patch clamp conditions. Measurement of the resting tension--sarcomere length curves in cells stored in solution containing streptomycin and penicillin revealed two populations of cells on the basis of their stiffness. CONCLUSIONS: This stretch induced increase in [Ca2+]i may be associated with stretch activated arrhythmias in the heart. The effects of streptomycin are consistent with its reported inhibitory action on stretch activated channels.

Animals↗
PubMed1994

Hypoxia activates a potassium current in isolated smooth muscle cells from large pulmonary arteries of the rabbit.

Severe hypoxia (< 10 mmHg) induced relaxation of precontracted rings obtained from large diameter (3-4 mm) pulmonary arteries of the rabbit but had no effect upon their basal tone nor upon the length of enzymatically isolated smooth muscle cells. In isolated smooth muscle cells severe hypoxia increased a voltage-gated K+ current. The magnitude of this response depended upon the degree of intracellular Ca2+ buffering, being abolished by 10 mM EGTA. The hypoxic response of K+ currents demonstrates a direct effect of hypoxia on pulmonary artery smooth muscle cells via a modulation of potassium channel activity.

Animals↗
PubMed1993

Measurements of sarcomere dynamics simultaneously with auxotonic force in isolated cardiac cells.

We developed an easy to use and non-invasive method to study sarcomere motion of enzymatically isolated myocytes which can be simultaneously combined with auxotonic force detection, thus being very useful when studying the contractile performance of cardiac cells. This method basically consists in analyzing the periodicity of the cell striation pattern using the Cooley-Tukey fast Fourier transform (FFT) algorithm on a video image of the cell during the course of the experiment. A longitudinal fraction of the cell image is recorded with a CCD TV camera, digitized, then transiently stored on a computer and used to calculate the spectrum corresponding to the distribution of the sarcomere lengths (SL). The method gives a real-time measurement of the most probable value of sarcomere length in one isolated cell with a temporal resolution of 20 ms. When used on a cell attached between two carbon fibers, the auxotonic force developed by the cell upon electrical stimulation can be simultaneously measured together with the SL in various conditions of stretch. Preliminary results have been presented in abstract form (Gannier et al., vol 24, pp. S47, 1992).

Animals↗