Biomedical subjects
Publications and source records attributed to A Legrand.
The complete coding sequence of the rabbit galectin-3-encoding cDNA (LGALS3) has been cloned in a single step by using RT-PCR and specific human LGALS3 cDNA primers. The putative protein contains three domains with different degrees of homology to other known LGALS3. The homology is high in the C-terminal moiety corresponding to the carbohydrate-binding domain and is relatively low in the N-terminal moiety.
In the present study, following previous experience with electrolytic lesion of the rat brain, and subsequent reduction of reactive gliosis with 7 beta-hydroxycholesterol derivatives (Bochelen et al.: Neuroscience 51:827-834, 1992), we have performed a hemisection of the spinal cord in adult rats and investigated the influence of 7 beta-hydroxycholesteryl-3-oleate (oxysterol) on the intensity of the astrocytic reaction and the axonal regeneration. We have shown here that local administration of liposomes containing this oxysterol reduced the intensity of the astroglial reaction on the sectioned side, as seen with immunocytochemical detection of glial fibrillary acidic protein (GFAP) and by in situ hybridization with a specific RNA probe. Moreover, radioautographic evaluation of astrocyte proliferation with tritiated thymidine evidenced a reduction of the astrocyte labelling index. In addition, double immunocytochemical detection of GFAP and polysialylated neural cell adhesion molecule (E-NCAM) revealed a decrease of the expression of this molecule in reactive astrocytes of the treated animals. Finally, immunocytochemical detection of serotonin (5HT) was determined in the raphespinal projections, which constitute a major descending system. In treated animals, serotonergic axons originating from the intact side reinnervated the dorsal horn of the sectioned side, below the hemisection. These results demonstrate that 7 beta-hydroxycholesteryl-3-oleate can reduce the astrocytic reaction following spinal cord injury, promoting the serotonergic reinnervation of a denervated territory.
Galectin-3 is a galactose-specific lectin which has been shown to be involved in several biological functions such as cell growth regulation, cell aggregation and cell differentiation. The partial cloning of the human genomic sequences reveals the presence of a 651 bp intron, 18 bp downstream of the translation initiation site. This intron contains several regulatory elements found in many eukaryotic genes. This sequence, when inserted upstream of a promoter-free luciferase gene, induces the expression of luciferase, demonstrating the promoter activity of the intron upon transfection in human or murine cells. This promoter activity is down-modulated by wild-type p53 but not by a mutated form of p53.
A mannose-specific membrane lectin (MR60) isolated from human myelomonocytic HL60 cells by affinity chromatography is expressed in intracellular organelles of immature monocytes (Pimpaneau, V., Midoux, P., Monsigny, M., and Roche, A. C. (1991) Carbohydr. Res. 213, 95-108). It is not present at the cell surface and is immunochemically and structurally distinct from the M(r) 175,000 mannose receptor of mature macrophages. MR60 cDNA was isolated and characterized; on the basis of its sequence, MR60 is not related to any known mammalian lectins. Surprisingly, MR60 was found to be identical to ERGIC-53 (Schindler, R., Itin, C., Zerial, M., Lottspeich, F., and Hauri, H.P. (1993) Eur. J. Cell Biol. 61, 1-9), a type I integral membrane protein, defined as a marker of the intermediate compartment that recycles between the Golgi apparatus and endoplasmic reticulum; MR60/ERGIC-53 shares with VIP-36 significant homologies with leguminous plant lectins (Fiedler, K., and Simmons, K. (1994) Cell 77, 625-626). We extend these findings in evidencing a structural homology between MR60/ERGIC-53 and mammalian galectins (soluble beta galactose binding proteins). MR60/ERGIC-53 is the first lectin characterized as an endoplasmic reticulum-Golgi protein. Accordingly, this intracellular mannose binding protein could be involved in the traffic of glycoproteins between endoplasmic reticulum and the Golgi apparatus.
Recent computations of the mechanical advantage of the canine intercostal muscles have suggested that the inspiratory advantage of the parasternal intercostals is not uniform. In the present studies, we have initially tested this hypothesis. Using a caliper and markers implanted in the costal cartilages, we have thus measured, in four supine paralyzed dogs, the length of the medial, middle, and lateral parasternal fibers at functional residual capacity and after a 1-liter mechanical inflation. With inflation, the medial fibers always shortened more than did the middle fibers (-9.8 +/- 0.8 vs. -6.0 +/- 0.8%; P < 0.001), whereas the lateral fibers remained virtually constant in length (-0.2 +/- 0.8%). This gradient of mechanical advantage agreed well with the gradient of orientation of the muscle fibers. Therefore, we have also recorded the electromyograms of the medial, middle, and lateral parasternal bundles during spontaneous breathing in nine anesthetized animals (20 interspaces); each activity was expressed as a percentage of the activity recorded during tetanic, supramaximal stimulation of the internal intercostal nerve (maximal activity). The medial bundle was invariably more active than was the middle bundle during resting breathing (57.3 +/- 3.3 vs. 25.5 +/- 3.4% of maximum; P < 0.001), and in 10 interspaces, medial activity consistently preceded middle activity at the onset of inspiration. These differences persisted during hypercapnia, during inspiratory resistive loading, as well as after phrenicotomy. Activity was never recorded from the lateral bundle.(ABSTRACT TRUNCATED AT 250 WORDS)
A method based on the release of tritiated water from [9,10(n)-3H] palmitic and myristic acids previously described for fibroblasts, was adapted for lymphocytes for the rapid diagnosis of fatty acid oxidation disorders. Optimal concentrations for both substrates and linearity of the assay were established. Normal values were established in control subjects of different age groups (58 children and 117 adults) and 16 patients with known fatty acid oxidation disorders were tested. Tritiated water production from patients' lymphocytes was expressed as a ratio between residual oxidations of palmitate and myristate and the results show that this method allows good differentiation between long chain and medium chain fatty acid oxidation defects.
Interleukin-1 (IL-1) and IL-6 are produced by Sertoli cells. As IL-1 stimulates IL-6 production in some tissues, the cascade of events that results in IL-6 secretion by Sertoli cells was studied. The addition of IL-1 alpha to Sertoli cells resulted in a time-dependent increase in IL-6 secretion. Incubation of Sertoli cells with two known stimulators of IL-1 production, lipopolysaccharide (LPS) and residual bodies, resulted in a significant increase in IL-1 release into the medium several hours before IL-6 release. That IL-1 is essential for IL-6 production from Sertoli cells was established by blocking the actions of LPS and residual bodies with an anti-IL-1 alpha antibody. An increase in the release of IL-1 before IL-6 was also observed in medium obtained from staged segments of intact seminiferous tubules; IL-1 reached a maximum level at stage VIII, when mature spermatozoa are released and residual bodies are formed and phagocytosed. The secretion of IL-6 was low during this stage and then increased progressively from stage IX onward, consistent with IL-1 stimulation of IL-6. The pathway of IL-1 alpha-induced release of IL-6 was studied in the presence of agents that influence arachidonic acid release and metabolism. IL-1 alpha was found to stimulate arachidonic acid release by Sertoli cells. Furthermore, a phospholipase A2 inhibitor, aristolochic acid, significantly decreased IL-1-, LPS-, and pyrularia pubera thionin-induced IL-6 secretion from Sertoli cells. Indomethacin, a specific inhibitor of the cyclooxygenase pathway, had no significant effect on basal, but enhanced IL-1- and LPS-stimulated IL-6 production. The involvement of arachidonic acid metabolites produced in the lipoxygenase pathway on the release of IL-6 was investigated indirectly, using nordihydroguaiaretic acid. This inhibitor reduced basal and IL-1 alpha- and LPS-stimulated IL-6 production. Ethacrynic acid, an inhibitor of peptido-leukotriene synthesis, also reduced basal IL-6 levels and blocked IL-1 alpha- as well as LPS-induced IL-6 secretion. It is concluded that IL-1 produced by Sertoli cells in response to LPS or residual bodies induces IL-6 through the lipoxygenase pathway.
In animals and man, serotonin (5-HT) exerts a direct stimulatory action on adrenocortical cells through activation of 5-HT4 receptors. In rats, 5-HT also potentiates the stimulatory effect of angiotensin-II (Ang II) on aldosterone secretion. The aim of the present study was to investigate the effect of concomitant administration of the 5-HT4 receptor agonist, cisapride, and Ang II on aldosterone secretion in normal human subjects. Eight healthy male volunteers pretreated with dexamethasone received, at 1-week intervals in random order and simple blind fashion, the following treatments: 1) a single oral dose of 10 mg cisapride, 2) a single oral dose of placebo, 3) a perfusion of graded doses of Ang II (from 1-4 ng/kg.min), 4) a perfusion of placebo, and 5) a single oral dose of 10 mg cisapride associated with a perfusion of Ang II. The oral doses of cisapride and placebo were also administered after a 3-day period of a low sodium diet (10 mmol/day). Plasma aldosterone levels increased significantly within 90 min after the administration of cisapride without any change in renin levels. The comparison between the net increase in aldosterone production induced by cisapride, Ang II, and cisapride plus Ang II showed that the stimulatory effects of cisapride and Ang II on aldosterone secretion were only additive. Similarly, the increase in plasma aldosterone levels induced by a sodium-restricted diet was just additive with the cisapride-evoked stimulation of aldosterone secretion. These results provide further evidence that the action of 5-HT on glomerulosa cells is mediated through activation of 5-HT4 receptors. The data also indicate that in humans, 5-HT does not potentiate the stimulatory effect of Ang II on aldosterone secretion.
Although low density lipoprotein receptors have been described on oligodendrocytes, apolipoprotein B was thought to be absent or present in only very small amounts in cerebrospinal fluid (CSF). Several immunoassays have been used for the measurement of apolipoprotein B in serum. However, the majority of methods cannot be used to measure small amounts of apolipoprotein B in CSF. In this study, we describe a highly sensitive time resolved immunofluorometric assay (TR-IFMA) using europium as label (detection limit: 0.3 microgram/l). The reliability of the TR-IFMA for the measurement of apolipoprotein B was first studied in serum. Serum and CSF apolipoprotein B concentrations were then determined in subjects free of neurological disorders and in patients with multiple sclerosis. Local intrathecal apolipoprotein B synthesis was calculated. Although the high sensitivity of the TR-IFMA allowed low amounts of apolipoprotein B in CSF to be detected (0.11 +/- 0.06; 0.12 +/- 0.06 mg/l in controls and multiple sclerosis patients, respectively), no apolipoprotein B could be detected in CSF by electroimmunodiffusion. As suggested by the blood/CSF apolipoprotein B ratio (about 6000), no apolipoprotein B synthesis was observed by both using apolipoprotein B index and formula. This indicates its probable serum origin. Moreover, there was no difference between controls and multiple sclerosis patients in CSF, serum, blood/CSF, index, and local intrathecal apoliprotein B synthesis. Finally, these results suggest that the role of apolipoprotein B in lipid transport in the central nervous system may be questionable.
1. The aims of the study were to assess the pharmacokinetic parameters and the hormonal effects of the slow-release formulation of the somatostatin analogue (SR-L) in normal male volunteers. 2. Eight healthy males were studied. For the determination of basal values blood was sampled before the injection of vehicle and then every other hour for 8 h in order to measure plasma GH, prolactin (PRL), TSH, free thyroxin (fT4), insulin and glucagon levels. Plasma insulin-like growth factor 1 (IGF-1) levels were measured on a single sample. On day 1 of the study, 30 mg SR-L was administered intramuscularly. Blood was drawn just before injection and then every other hour for a period of 8 h. Thereafter, blood was sampled three times a week for 3 weeks in order to measure lanreotide, IGF-1, TSH, fT4 and PRL concentrations. Plasma GH was determined on days 6 and 11 of the study. 3. Plasma lanreotide concentrations rose to 38.3 +/- 4.1 ng ml-1 2 h following injection. The levels then progressively decreased, remaining above 1.5 ng ml-1 until day 11 and reaching 0.92 +/- 0.28 ng ml-1 2 weeks after injection. The apparent plasma half-life and mean residence time were 4.52 +/- 0.50 and 5.48 +/- 0.51 days respectively. 4. By comparison with the control day, plasma insulin concentrations only decreased 2 h following injection, whereas plasma glucagon did not change at any time. 5. Plasma TSH concentrations were significantly (P < 0.01) reduced from 2 h to day 4 following SR-L injection.2+ '
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Endothelial cells from mouse peripheral lymph nodes were immortalized by cationic liposome-mediated transfection using a plasmid construct containing both the gene coding for the large T antigen of simian virus 40 and a geneticin resistance gene suitable for selection. A cell line (HECa10) was isolated on the basis of its capacity to specifically bind fucoside carrying glycoconjugates; these cells present the main characteristics of endothelial cells: production of angiotensin converting enzyme and of factor VIII-related antigen. Upon stimulation, they express E-selectin which binds oligosaccharides containing the Lewisx determinant (Fuc alpha 3[Gal beta 4 GlcNAc beta 3Gal beta) and the MECA 79 addressin which is characteristic for the peripheral lymph node high endothelium and is a L-selectin ligand. HECa10 cells, as well as peripheral lymph node high endothelial cells in primary culture, express a second fucoside binding protein which differs from E-selectin. Indeed, this new fucoside-binding protein is constitutively expressed on unstimulated cells while E-selectin is not. Furthermore, HECa10 cells mediate selective lymphoid cell adhesion in a selectin/addressin-dependent mechanism, mainly inhibited by MECA 79 antibody and, in a fucose-binding lectin-dependent manner, mainly inhibited by the specific neoglycoprotein.
This work aimed at providing by means of immunocytochemical techniques a detailed study of the ontogeny of thyrotropin-releasing hormone (TRH) in the spinal cord of the rat. We report the first appearance of TRH-immunoreactive fibers in the ventral funiculus of thoracic and lumbar levels at embryonic day 17. At embryonic day 18, fibers penetrated the ventral gray matter towards the central canal. At embryonic day 19, the first immunoreactive fibers were seen in the intermediolateral cell column at upper thoracic levels. This region was invaded at lower thoracic levels on the day of birth. At this time, TRH-immunoreactive axodendritic synapses were observed in the ventral horn and in the intermediolateral cell column. Immunoreactivity increased in these regions until post-natal day 21 when the adult pattern of TRH immunoreactivity was established in the sympathetic nuclei and in the ventral horn. However, a transient TRH-like immunoreactivity was detected in lamina IIi of the dorsal horn between post-natal days 14 and 30: at ultrastructural level, immunoreactive varicosities were seen to establish axodendritic synapses. In conclusion, TRH is one of the earliest peptidergic systems established in the spinal cord and it presents extensive temporal and topographical similarities with the serotonergic system with which it could be colocalized.
Hypertriglyceridemia is the most frequent modification of lipid metabolism observed in acromegaly. The somatostatin analog, octreotide (Sandostatin), widely used in the treatment of acromegaly, is able to produce a decrease in levels of growth hormone (GH), insulin, and Insulin-like Growth Factor 1 (IGF1). We have attempted to evaluate the influence of this treatment on the lipid status of acromegalic patients. Seventeen patients with active acromegaly were treated with octreotide, 100 to 500 micrograms/injection subcutaneously three times daily. The levels of fasting serum triglycerides (TG), total cholesterol, High Density Lipoprotein (HDL) cholesterol and IGF1, as well as mean plasma GH and insulin levels during a diurnal profile, were evaluated before and after three months of octreotide therapy. GH, insulin and IGF1 decreased by 61%, 42% and 36% respectively (p less than 0.05). Mean levels (+/- SEM) of TG and total cholesterol fell from 2.2 +/- 0.4 mmol/l to 1.6 +/- 0.3 mmol/l (p less than 0.05) and 6.4 +/- 0.39 mmol/l to 5.6 +/- 0.27 mmol/l (p greater than 0.05), respectively. There was no correlation between triglyceride decrease and hormonal changes or clinical status (BMI, age, sex). In conclusion, the administration of octreotide over a three month period to acromegalic patients is associated with a decrease in TG levels.
OBJECTIVE: To examine the distribution of Lp(a) plasma levels in patients with IDDM and NIDDM, and in nondiabetic and IDDM patients with chronic renal failure. RESEARCH DESIGN AND METHODS: Cross-sectional study of Lp(a) plasma levels in a population of diabetic patients with stable metabolic control, with simultaneous determination of plasma lipids, fasting plasma glucose, and HbA1. Thirty-six patients with IDDM, 90 with NIDDM, and 41 with chronic renal failure (20 IDDM, 21 nondiabetic) were compared with 78 control subjects. RESULTS: Lp(a) plasma levels were significantly higher in IDDM and NIDDM patients, as well as in nondiabetic and IDDM patients with chronic renal failure compared with control subjects. No correlation was observed between Lp(a) and lipid plasma levels, fasting plasma glucose, and HbA1. CONCLUSIONS: Lp(a) may contribute to the increased prevalence of atherosclerotic disease in diabetic patients and patients with chronic renal failure, especially in IDDM patients whose lipoprotein pattern was not different from that of the control group.
We assessed the distribution of alpha-tocopherol in serum lipoprotein samples after separating the lipoprotein fractions by either sequential ultracentrifugation or selective precipitation with sodium phosphotungstate-magnesium chloride reagent. alpha-Tocopherol concentrations were determined by reversed-phase high-performance liquid chromatography. After ultracentrifugation, we found that in men, low- and very-low-density serum lipoproteins (LDL-VLDL) contained 53.6% of alpha-tocopherol vs 46.4% in high-density lipoproteins (HDL). In women, serum LDL-VLDL contained 45.6% alpha-tocopherol after ultracentrifugation vs 54.4% in HDL. After selective precipitation, the proportions of alpha-tocopherol in men were 56.1% in LDL-VLDL vs 43.9% in HDL, and in women, 45.4% in LDL-VLDL vs 54.6% in HDL. After selective precipitation, alpha-tocopherol recovery from whole lipoprotein fractions was 97% to 100% vs 80% after ultracentrifugation, thus allowing more accurate alpha-tocopherol quantification than after separation by ultracentrifugation.
The plasmid pSV3-neo that carries the SV40 early genetic region and the neor resistance gene underwent homologous recombination between SV40-duplicated sequences of the small t antigen intron and the polyadenylation site after transfection into rabbit vascular smooth muscle cells. This recombination yielded two free plasmids of 1.7 and 3.0 kb that replicated in transfected rabbit cells, while the vector plasmid did not. Replication of the two recombinant plasmids continued for several months in rabbit cells transformed by pSV3-neo, and their structure remained unchanged. Between 15 and 2,510 copies per cell of the 3.0-kb plasmid and between 370 and 1,565 copies per cell of the 1.7-kb plasmid were found in different pSV3-neo-transformed rabbit clones. Similar recombined plasmids were found 3 days after transfection of pSV3-neo onto SV40-transformed rabbit cells. By comparison, pSV3-neo was replicated in simian cells, but no recombined plasmids were detected by Southern analysis. No replication was detected after transfection of pSV3-neo into mouse cells. These results appear to reflect important differences between rabbit and simian cells in the efficiency of homologous recombination involving specific SV40 sequences and/or in the replication of the resulting recombinants. The role of the host cell in the evolution of SV40 sequences may influence the outcome of the infection with this virus.
We report 3 sisters treated for cerebrotendinous xanthomatosis. We treated one, with a severe neurologic form of the illness, with chenodeoxycholic acid, then lovastatin and simvastatin. These drugs had different efficacy and tolerance, but induced no clinical improvement. Her sisters, without neurologic symptoms, received chenodeoxycholic acid, which normalized the cholestanol level. Optimal treatment of this illness must begin before there is significant clinical symptomatology.