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A Tall

Publications and source records attributed to A Tall.

At least 73 records · Page 4Linked to original sources
PubMed1997

[Tracheotomy in the child with a foreign body in the lower respiratory passages].

In 15 years period, 137 children with foreign bodies of inferior respiratory tracts were admitted in the otorhinolaryngology and head and neck department of the University of Dakar. For 48 of them, generally late admitted, a tracheostomy was performed. Male children were most affected. About 81% of the removed foreign bodies were organic, dominated by peanuts. 76% of the foreign bodies were found in the larynx. Tracheostomy had been realized before extraction of foreign body for 90% of the cases and after extraction for the others 10%. One case of death was to be deplored. This critical place of tracheostomy increases the morbidity and the mortality in relation with the inhalation of foreign body. This unusual practice of tracheostomy illustrates the arduousness of our working conditions.

Adolescent↗
PubMed1996

Interleukin 8 is induced by cholesterol loading of macrophages and expressed by macrophage foam cells in human atheroma.

In order to identify novel genes expressed in macrophage-derived foam cells, we used a multigene assay to examine the expression of genes in control versus cholesterol-loaded macrophages. We compared THP-1 macrophages incubated with or without acetylated LDL (acLDL) +/- acyl-CoA:cholesterol O-acyltransferase (ACAT) inhibitor (compound 58035) for 20 h and assessed changes in mRNA of chemokines, growth factors, interleukins, and adhesion molecules. Among 49 genes examined, an increase in mRNA was observed only for interleukin 8 (IL-8) in THP-1 macrophages. Northern analysis confirmed a 3- to 4-fold increase of IL-8 mRNA and an enzyme-linked immunosorbent assay (ELISA) revealed a corresponding increase in IL-8 in conditioned medium. Oxidized LDL (oxLDL) also induced IL-8 mRNA, but native LDL had no effect. 58035 had a moderate effect on IL-8 induction by acLDL. AcLDL-induced IL-8 expression was concentration- and time-dependent. The time course of IL-8 induction paralleled that of cholesterol loading. MCP-1, a chemokine implicated in recruiting monocytes in atherogenesis, was also induced by acLDL. The induction of MCP-1, however, peaked at 1 h after addition of acLDL and returned to basal level by 20 h while IL-8 induction peaked at 8 h and was still 2-fold higher than basal level at 20 h. IL-8 induction was also observed in fresh human monocyte-derived macrophage cells treated with acLDL. Finally, immunohistochemistry and in situ hybridization studies using specimens of human coronary atheromas showed expression of IL-8 mRNA in a macrophage-rich area. We conclude that IL-8 is induced in macrophage foam cells as a response to cholesterol loading. The chemoattractant and/or mitogenic effects of IL-8 on neutrophils, T cells, smooth muscle, or vascular endothelial cells may contribute to the progression and complications of atherosclerosis.

Arteriosclerosis↗
PubMed1996

Structure-function relationships of human cholesteryl ester transfer protein: analysis using monoclonal antibodies.

Cholesteryl ester transfer protein (CETP), a 476 amino acid glycoprotein, mediates cholesteryl ester (CE), triglyceride, and phospholipid transfer among plasma lipoproteins. A monoclonal antibody (mAb), TP2, specific for an epitope within the last 26 amino acids of CETP has been shown to block all CETP-mediated lipid transfer, apparently by limiting access to lipid-binding sites in the carboxy terminal of CETP. A new panel of 16 anti-human CETP mAbs has now been used to further probe the structure-function relationships of CETP. Of the new mAbs, 9 partially inhibit CETP-mediated CE transfer (24-43%) from HDL to LDL. The corresponding epitopes were mapped within the CETP primary structure by the reactivity of the mAbs with CETP variants having deletions or amino acid substitutions. Of the 9 new, neutralizing mAbs, 6 are specific for epitopes situated between residues 410-450 and two others for epitopes between residues 184-260 and 332-366, respectively. The epitope of one neutralizing mAbs could not be mapped. Therefore, binding of mAbs to epitopes situated in four non-overlapping regions within CETP primary structure that are separated by as many as 280 residues can neutralize CETP-mediated CE transfer. Epitopes of mAbs that do not influence CE transfer activity map to the regions 184-260, 261-331, and 367-409, respectively. When pairs of mAbs were tested for their abilities to mutually compete for binding to immobilized CETP, competition was observed for mAbs specific for epitopes that are distant in CETP primary structure. The cross-competition patterns demonstrate that the carboxy terminal 60% of CETP adopts a compact structure. Together with previous mutagenesis studies, the data suggests that a carboxy terminal neutral lipid binding domain may be in close proximity to a lipoprotein binding region within native CETP.

Animals↗
PubMed1996

[In vitro sensitivity of 85 Plasmodium falciparum isolates in the Fatick region, Senegal].

Increasing resistance of Plasmodium falciparum to chloroquine and other antimalarials has been reported in Africa. Only fragmentary data are available for Senegal. Although combined chloroquine-proguanil is soon scheduled for released on the market, few studies have been published concerning the susceptibility of isolates to either drug. The in vitro susceptibility of 85 Plasmodium falciparum isolates obtained between October 24 and December 2, 1995 from malaria-infected patients living in the Fatick Region of Senegal to five classical antimalarial drugs (chloroquine, cycloguanil, quinine, mefloquine, and halofantrine) was evaluated using an isotopic, semi-microtest. Twenty-nine percent of isolates were resistant to chloroquine (IC50 > 100 nM), 22% to cycloguanil (IC50 > 500 nM), 1% to quinine (IC50 > 500 nM), 22% to mefloquine (IC50 > 20 nM), and 8% to halofantrine (IC50 > 5 nM). Five percent of isolates were resistant to both chloroquine and cycloguanil. Positive correlation was observed between quinine and halofantrine activity and between mefloquine and halofantrine activity. These findings suggest cross resistance or reduced susceptibility between these antimalarial agents which all exhibit a methanolic function.

Animals↗
PubMed1995

Defective binding of neutral lipids by a carboxyl-terminal deletion mutant of cholesteryl ester transfer protein. Evidence for a carboxyl-terminal cholesteryl ester binding site essential for neutral lipid transfer activity.

The plasma cholesteryl ester transfer protein (CETP, 476 amino acids) transfers cholesteryl ester (CE) from high density lipoprotein (HDL) to triglyceride-rich lipoproteins and plays a major role in HDL catabolism. Using deletional and site-directed mutagenesis, we previously showed that the carboxyl terminus of human CETP comprises the epitope of a neutralizing monoclonal antibody and is necessary for neutral lipid transfer activity. To assess the nature of the involvement of the COOH terminus in cholesteryl ester transfer activity, we characterized a deletion mutant of CETP lacking amino acid residues 470-475 in terms of CE transfer kinetics, association with HDL, and capacity to bind CE, triglyceride (TG), and phosphatidylcholine (PC). Kinetic analysis indicated a major catalytic defect of the deletion mutant, as shown by markedly decreased maximum cholesteryl ester transfer activities (apparent Vmax) for donor (HDL) and acceptor (low density lipoprotein (LDL)) lipoproteins but there were no significant changes of concentrations of the donor and acceptor at 50% Vmax (apparent Km). The binding of CETP to HDL, as determined by native gel electrophoresis, was similar for wild-type and mutant protein. When egg PC/CE vesicles were incubated with wild type CETP and then separated by gel filtration chromatography, there was maximum binding of about 1 mol of CE/mol of CETP. Under similar conditions the mutant CETP bound 0.09-0.37 mol of CE/mol of protein. Similarly, when egg PC/TG vesicles were incubated with the CETP proteins, there was a maximum binding of 0.5 mol of triglyceride/mol of wild-type CETP, whereas there was only 0.00-0.07 mol of TG/mol of deletion mutant. The binding of phosphatidylcholine was similar for wild-type and the deletion mutant. The studies suggest that amino acids 470-475 (forming part of a COOH-terminal amphipathic helix) are involved in CE and TG binding by CETP but are not required either for the binding of PC by CETP or the association of CETP with HDL. The COOH terminus of CETP may comprise a neutral lipid binding site directly involved in the lipid transfer mechanism.

Animals↗
PubMed1995

Plasma lipid transfer proteins.

The plasma lipid transfer proteins mediate the transfer and exchange of phospholipids and neutral lipids between the plasma lipoproteins. The cholesteryl ester transfer protein (CETP) and the phospholipid transfer protein (PLTP) are members of the lipid transfer/lipopolysaccharide binding gene family. The CETP contains binding sites for cholesteryl ester and triglycerides and probably acts by a carrier-mediated mechanism. The CETP mediates catabolism of HDL cholesteryl esters, with secondary decreases in HDL size and protein content. The CETP plays a central role in reverse cholesterol transport i.e. the centripetal movement of cholesterol from the periphery back to the liver. CETP gene expression is upregulated in response to increased dietary cholesterol or endogenous hypercholesterolemia. Although CETP reduces HDL levels, its role in reverse cholesterol transport suggests a dominant anti-atherogenic action in vivo.

Acute-Phase Proteins↗
PubMed1995

Decreased cholesteryl ester transfer protein (CETP) mRNA and protein and increased high density lipoprotein following lipopolysaccharide administration in human CETP transgenic mice.

The plasma cholesteryl ester transfer protein (CETP) mediates the exchange of HDL cholesteryl esters (CE) and VLDL triglycerides leading to catabolism of HDL. There is some evidence that HDL ameliorates the toxicity of LPS, and LPS is known to influence several enzymes affecting HDL metabolism. Therefore, the effects of LPS on CETP and plasma lipoproteins were examined in human CETP transgenic mice. Administration of LPS to mice expressing a CETP transgene linked to its natural flanking sequences (NFR-CETP Tg) resulted in a rapid marked decrease in hepatic CETP mRNA and plasma CETP concentration. Corticosteroid injection produced a similar decrease in hepatic CETP mRNA and adrenalectomy abolished this response to LPS. LPS caused disproportionate reductions in plasma CETP activity compared to mass, and was found to be a potent inhibitor of CETP activity when added directly to plasma. LPS was injected into mice expressing (A) a human apoA-I transgene, (B) apoA-I and NFR-CETP transgenes, or (C) apoA-I and LPS-inducible metallothionein promoter-driven CETP transgenes, producing (A) minimal changes in HDL cholesterol, (B) decreased plasma CETP and increased HDL cholesterol, and (C) increased plasma CETP and decreased HDL cholesterol. Thus, LPS administration produces a profound decrease in hepatic CETP mRNA, primarily as a result of adrenal corticosteroid release. The decrease in plasma CETP activity after LPS administration may reflect both this effect as well as a direct interaction between CETP and LPS. The decrease of CETP in response to LPS has major effects on HDL levels, and may represent an adaptive response to preserve or increase HDL and thereby modify the response to LPS.

Animals↗
PubMed1995

Cholesterol efflux potential of sera from mice expressing human cholesteryl ester transfer protein and/or human apolipoprotein AI.

The ability of whole serum to promote cell cholesterol efflux and the relationships between apoprotein and lipoprotein components of human serum efflux have been investigated previously (de la Llera Moya, M., V. Atger, J.L. Paul, N. Fournier, N. Moatti, P. Giral, K.E. Friday, and G.H. Rothblat. 1994. Arterioscler. Thromb. 14:1056-1065). We have now used this experimental system to study the selective effects of two human lipoprotein-related proteins, apoprotein AI (apo AI) and cholesteryl ester transfer protein (CETP) on cell cholesterol efflux, when these proteins are expressed in transgenic mice. The percent efflux values for cholesterol released in 4 h from Fu5AH donor cells to 5% sera from the different groups of mice were in the order: background = human apo AI transgenic (HuAITg) > human CETP transgenic (HuCETPTg) > human apo AI and CETP transgenic (HuAICETPTg) >> apo AI knockout mice. In each group of mice a strong, positive correlation (r2 ranging from 0.64 to 0.76) was found between efflux and HDL cholesterol concentrations. The slopes of these regression lines differed between groups of mice, indicating that the cholesterol acceptor efficiencies of the sera differed among groups. These differences in relative efficiencies can explain why cholesterol efflux was not proportional to the different HDL levels in the various groups of mice. We can conclude that: (a) HDL particles from HuAITg mice are less efficient as cholesterol acceptors than HDL from the background mice; (b) despite a lower average efflux due to lower HDL cholesterol concentrations, HDL particles are more efficient in the HuCETPTg mice than in the background mice; and (c) the coexpression of both human apo AI and CETP improves the efficiency of HDL particles in the HuAICETPTg mice when compared with the HuAITg mice. We also demonstrated that the esterification of the free cholesterol released from the cells by lecithin cholesterol acyltransferase in the serum was reduced in the HuAITg and AI knockout mice, whereas it was not different from background values in the two groups of mice expressing human CETP.

Animals↗
PubMed1994

Human ApoA-II inhibits the hydrolysis of HDL triglyceride and the decrease of HDL size induced by hypertriglyceridemia and cholesteryl ester transfer protein in transgenic mice.

The plasma cholesteryl ester transfer protein (CETP) mediates the exchange of HDL cholesteryl esters with triglycerides of other lipoproteins. Subsequent lipolysis of the triglyceride-enriched HDL by hepatic lipase leads to reductions of HDL size and apoA-I content. To investigate a possible modulation of the effects of CETP by apoA-II, human CETP transgenic mice were cross-bred with transgenic mice expressing human apoA-II and, in some cases, human apoA-I and apoC-III (with human-like HDL and hypertriglyceridemia). CETP expression resulted in reductions of HDL and increases in VLDL cholesteryl ester in mice expressing human apoA-II, alone or in combination with apoA-I and apoC-III, indicating that apoA-II does not inhibit the cholesteryl ester transfer activity of CETP. However, CETP expression resulted in more prominent increases in HDL triglyceride in mice expressing both apoA-II and CETP, especially in CETP/apoA-II/apoAI-CIII transgenic mice. CETP expression caused dramatic reductions in HDL size and apoA-I content in apoAI-CIII transgenic mice, but not in apoA-II/AI-CIII transgenic mice. HDL prepared from mice of various genotypes showed inhibition of emulsion-based hepatic lipase activity in proportion to the apoA-II/apoA-I ratio of HDL. The presence of human apoA-II also inhibited mouse plasma hepatic lipase activity on HDL triglyceride. Thus, apoA-II does not inhibit the lipid transfer activity of CETP in vivo. However, coexpression of apoA-II with CETP results in HDL particles that are more triglyceride enriched and resistant to reductions in size and apoA-I content, reflecting inhibition of hepatic lipase by apoA-II. The inhibition of HDL remodeling by apoA-II could explain the relatively constant levels of HDL containing both apoA-I and apoA-II in human populations.

Animals↗
PubMed1994

[Frontal sinus mucoceles apropos of 35 cases].

35 cases of frontal sinus mucoceles treated from 1977 to 1991 are reported. The average of age was 41 years with 74% of men. The clinical presentation was a frontal or fronto-orbital pyocele in 40% of the cases, with palpebral fistula in 11 cases; one patient had visual loss. Unilateral exophtalmos was the initial complaint among five patients (14%). Surgical treatment, surrounded by massive antibiotherapy, required always curettage and aeration of the sinus by desobstruction of the nasofrontal duct and insertion of a tube in the duct to the nasal cavity. Exenteration was mandatory in one patient. Failure was due to recurrence in 3 cases. The gravity of paranasal sinuses mucoceles prescribe a correct evaluation of their usual predisposing factors.

Adult↗
PubMed1993

Down-regulation of mRNA for the low density lipoprotein receptor in transgenic mice containing the gene for human cholesteryl ester transfer protein. Mechanism to explain accumulation of lipoprotein B particles.

To evaluate the effects of cholesteryl ester transfer protein (CETP) on apoB-containing lipoproteins, we analyzed plasma lipoproteins from three different lines of human CETP transgenic mice, with plasma CETP concentration ranging from low (1.5 microgram/ml) to high levels (8.5 micrograms/ml). With increasing CETP concentration, very low density lipoprotein and low density lipoprotein (LDL) cholesteryl ester (CE) and apoB were progressively increased, and high density lipoprotein CE was decreased. To investigate the mechanism of accumulation of lipoproteins containing apoB (lipoprotein B), the abundance of hepatic LDL receptor mRNA was determined. LDL receptor mRNA was reduced as a result of CETP expression, with maximum repression to about 48% of the level of non-transgenic mice. Among the different lines of CETP transgenic mice there was an inverse relationship between plasma CETP concentration and hepatic LDL receptor mRNA abundance (r = -0.94, p < 0.01). CETP expression also led to increased cholesterol and cholesteryl ester content in liver and to decreased abundance of mRNAs encoding 3-hydroxy-3-methylglutaryl-coenzyme A reductase and 7-alpha-hydroxylase. Thus, CETP expression results in increased cholesteryl ester concentration in very low density lipoprotein and LDL, probably reflecting both CE transfer from high density lipoprotein and accumulation of lipoprotein B particles. The accumulation of lipoprotein B particles results from CETP-mediated down-regulation of liver LDL receptors, possibly due to enhanced return of cholesterol to the liver.

Animals↗
PubMed1993

Inhibition of the cellular secretion of cholesteryl ester transfer protein by a variant protein formed by alternative splicing of mRNA.

Alternative splicing of mRNA is often used as a regulatory switch, determining whether a functional protein is made or not. The plasma cholesteryl ester transfer protein (CETP) mediates the transfer of cholesteryl esters from high density lipoproteins to other lipoproteins. In addition to the mRNA encoding plasma CETP, human tissues contain an alternatively spliced variant in which exon 9-derived sequences are omitted. To determine a possible regulatory role of alternative splicing, COS cells were co-transfected with full-length and exon 9-deleted cDNAs. The exon 9-deleted protein was poorly secreted and inhibited the secretion of full-length CETP, due to formation of an intracellular heteromeric complex between full-length and exon 9-deleted proteins. The findings suggest a novel use of alternative splicing to generate a poorly secreted protein variant, which complexes with the active form and prevents its secretion by cells.

Animals↗
PubMed1993

Exercise training decreases plasma cholesteryl ester transfer protein.

To assess the effect of exercise on the plasma concentration of cholesterol ester transfer protein (CETP) and its possible influence in mediating the exercise-associated redistribution of cholesterol among plasma lipoproteins, we measured plasma CETP in 57 healthy normolipidemic men and women before and after 9 to 12 months of exercise training. The training protocol resulted in significant changes in VO2max (mean +/- SD, +5.3 +/- 3.5 mL.kg-1 x min-1), body weight (-2.5 +/- 3.5 kg), plasma triglycerides (-25.7 +/- 36.3 mg/dL), high-density lipoprotein cholesterol (HDL-C) (+2.6 +/- 6.2 mg/dL), and ratios of total cholesterol to HDL-C (-0.30 +/- 0.52) and low-density lipoprotein cholesterol (LDL-C) to HDL-C (-0.18 +/- 0.45) (all P < or = .05) but no change in lipoprotein(a). CETP concentration (in milligrams per liter) fell significantly in response to training in both men (n = 28, 2.47 +/- 0.66 to 2.12 +/- 0.43; % delta = 14.2%; P < .005) and women (n = 29, 2.72 +/- 1.01 to 2.36 +/- 0.76; % delta = 13.2%; P < .047). The CETP change was observed both in subjects who lost weight (n = 28, delta mean weight = -5.0 kg; delta CETP = -0.42 +/- 0.79; % delta = 15.4%; P < .009) and in those who were weight stable (n = 29, delta mean weight = -0.12 kg; delta CETP = -0.29 +/- 0.78; % delta = 10.4%; P < .055).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1992

Dietary cholesterol increases transcription of the human cholesteryl ester transfer protein gene in transgenic mice. Dependence on natural flanking sequences.

To investigate the regulation of expression of the human cholesteryl ester transfer protein (CETP) gene, transgenic mice were prepared using a CETP minigene linked to the natural flanking sequences of the human CETP gene. By using a transgene containing 3.2 kb of upstream and 2.0 kb of downstream flanking sequence, five different lines of transgenic mice were generated. The abundance of CETP mRNA in various tissues was determined on standard laboratory diet or high fat, high cholesterol diets. In three lines of transgenic mice the tissues expressing the human CETP mRNA were similar to those in humans (liver, spleen, small intestine, kidney, and adipose tissue); in two lines expression was more restricted. There was a marked (4-10-fold) induction of liver CETP mRNA in response to a high fat, high cholesterol diet. The increase in hepatic CETP mRNA was accompanied by a fivefold increase in transcription rate of the CETP transgene, and a 2.5-fold increase in plasma CETP mass and activity. In contrast, CETP transgenic mice, in which the CETP minigene was linked to a metallothionein promoter rather than to its own flanking sequences, showed no change in liver CETP mRNA in response to a high cholesterol diet. Thus (a) the CETP minigene or natural flanking sequences contain elements directing authentic tissue-specific expression; (b) a high cholesterol diet induces CETP transgene transcription, causing increased hepatic CETP mRNA and plasma CETP; (c) this cholesterol response requires DNA sequences contained in the natural flanking regions of the human CETP gene.

Animals↗
PubMed1992

[Lethal midline granuloma in Senegal. (Apropos of 15 cases)].

African authors, other than senegalese, have not paid enough attention to lethal granuloma, a terrible disease. This series is about a series collected between 1975 and 1990. It is particularly high compared to other series in the world. If diagnosis is easy for the clinician, much care must surround the pathological answer. Those diagnosis problems and difficulties of treatment (represented by 11 deaths) are studied.

Adolescent↗
PubMed1991

Plasma lipid transfer protein as a determinant of the atherogenicity of monkey plasma lipoproteins.

This study was undertaken to determine potential tissue sources of plasma cholesteryl ester transfer protein (CETP), and to assess the influence of CETP on lipoprotein concentrations and atherosclerosis. In a group of 28 cynomolgus monkeys fed high fat, high cholesterol diets, plasma CETP concentration was strongly correlated with the abundance of CETP mRNA in liver and in adipose tissue, and with the output of CETP in liver perfusates. Plasma CETP concentration showed a strong inverse correlation with HDL cholesterol concentrations (r = -0.62, P less than 0.001) and a positive correlation with LDL cholesterol concentration (r = 0.54, P less than 0.005) and molecular weight (r = 0.57, P less than 0.001). The extent of coronary artery atherosclerosis was positively correlated with LDL cholesterol concentration and molecular weight, and with plasma CETP concentration. Thus, in monkeys fed an atherogenic diet, individual variation in CETP mRNA abundance in liver and adipose tissue probably plays a major role in the determination of plasma CETP levels. In plasma, CETP influences the distribution of cholesteryl esters between LDL and HDL, and CETP concentration appears to be a key determinant of the relative atherogenicity of the plasma lipoproteins.

Animals↗
PubMed1991

[Limits to the practice of craniofacial oncology in Black Africa: the example of cancer of the larynx].

Cervico-facial carcinology is currently one of the major concerns of oto-rhino-laryngologists. The authors have chosen laryngeal cancers to determine the limits of the practice of such cervico-facial carcinology in the topics. Over a 10-year period, 61 patients with a suspected malignant laryngeal disease were examined at the E.N.T. Clinic of the University Hospital in Dakar. Histological confirmation was found in only 38 patients, and a curative treatment was undertaken with 27 patients. No significant differentiation could be found from the results as far as sex, age and histology were concerned. On the other hand, the TNM breakdown of our 36 carcinomas revealed that in 78% of the cases large tumours (T3, T4) were involved. In the vast majority of these cases (18/27), treatment was purely surgical, with a total laryngectomy in 90% of the cases. Pharyngostomas accounted for the majority of the early postoperative complications (6/14). Over 10 years of practice, 70% of our patients have died or have been lost from sight. These poor results are due to numerous factors, including late consultation, the lack of specialists and the insufficiency of technical facilities. To improve results, the authors recommended the setting-up of proper cancer institutes.

Adult↗