Search PubMed⌕ Search

Biomedical subjects

P Julien

Publications and source records attributed to P Julien.

At least 55 records · Page 3Linked to original sources
PubMed1993

An exceptional representation of Saints Cosmas and Damian.

Exceptional for several reasons: its structure (two Limoges plaques meant to decorate both sides of a purse); the scene showing Saint Cosmas placing small change in the hat extended to him by a beggar; the representation of Saint Damian before the shelves of a pharmacy.

France↗
PubMed1993

Genealogy and regional distribution of lipoprotein lipase deficiency in French-Canadians of Quebec.

Lipoprotein lipase (LPL) deficiency, an autosomal recessive disorder causing chylomicronemia, has a high prevalence in the French-Canadian population of Quebec. The molecular basis of LPL deficiency has been defined, and two major mutations have been shown to have an uneven geographic distribution. Two mutations, one at residue 188 (M-188) and the other at residue 207 (M-207), are described here; they account for 95% of the mutant alleles. The carrier rate of M-188 was highest in western Quebec (1/326) but that of M-207 was much higher in the eastern part of the province (1/85). Genealogical reconstruction has revealed that both mutations were introduced to the French-Canadian population by migrants from France in the seventeenth century. M-188 is likely to have a Scottish ancestor, whereas M-207 appears to be of French origin.

France↗
PubMed1992

Alterations in erythrocyte membrane lipid composition and fluidity in primary lipoprotein lipase deficiency.

Lipid composition of plasma lipoproteins and erythrocyte ghost membranes has been studied in 16 healthy normolipidaemic subjects and in 16 patients affected by primary lipoprotein lipase deficiency, resulting in severe chylomicronaemia and in cholesterol-depleted low-density lipoproteins and high-density lipoproteins. A significant decrease in membrane cholesterol/phospholipid ratio was observed in lipoprotein lipase deficient patients compared to controls (3.27 +/- 0.33 vs. 3.95 +/- 0.50, mean +/- S.D.; P less than 0.0001). There was also an increase in the erythrocyte membrane phosphatidylcholine/sphingomyelin ratio in lipoprotein lipase deficient patients compared to controls (1.53 +/- 0.10 vs. 1.05 +/- 0.13; P less than 0.0001) due to a concurrent increase in phosphatidylcholine and decrease in sphingomyelin relative concentrations in these patients. Erythrocyte ghost membrane fluidity was determined by fluorescence anisotropy and found to be higher in membranes from lipoprotein lipase deficient patients. This increase in membrane fluidity can be attributed in part to changes in membrane cholesterol and phospholipid concentrations in response to abnormal plasma lipoprotein composition.

Adolescent↗
PubMed1992

Geographic distribution and genealogy of mutation 207 of the lipoprotein lipase gene in the French Canadian population of Québec.

Mutations in the lipoprotein lipase (LPL) gene, leading to partial or total inactivation of the enzyme, result in a hereditary clinical syndrome called familial LPL deficiency. The French Canadian population, which is primarily and historically located in the province of Québec, has the highest worldwide frequency of LPL-deficient patients. We have analyzed the prevalence, spatial distribution, and genealogy in the Québec population of a LPL gene mutation, M-207 (P207L in conventional notation), which changes the amino acid proline to leucine in position 207 of the LPL protein and inactivates the enzyme. Our results show that M-207 is the most prevalent LPL gene mutation among French Canadians and accounts for the largest proportion of LPL-deficient patients in this population. Genealogical reconstruction of French Canadian LPL-deficient patients point to 16 founders of M-207, all of whom migrated to Québec in the early seventeenth century from the north-western part of France, especially from the region of Perche. Most of the carriers of M-207 are, at present, found in Charlevoix, Saguenay-Lac-St-Jean regions of eastern Québec. On the basis of the number of homozygote M-207 LPL-deficient patients so far identified, we estimate that there are at least 31,000 carriers of this mutation in the province of Québec. This constitutes a large pool of individuals at risk for atherosclerosis and other lipid-related diseases, since LPL deficiency is considered to be a significant contributing factor in the etiology and development of these diseases.

Alleles↗
PubMed1992

A missense mutation (Asp250----Asn) in exon 6 of the human lipoprotein lipase gene causes chylomicronemia in patients of different ancestries.

We have previously reported two common lipoprotein lipase (LPL) gene mutations underlying LPL deficiency in the majority of 37 French Canadians (Monsalve et al., 1990. J. Clin. Invest. 86: 728-734; Ma et al., 1991. N. Engl. J. Med. 324: 1761-1766). By examining the 10 coding exons of the LPL gene in another French Canadian patient, we have identified a third missense mutation that is found in two of the three remaining patients for whom mutations are undefined. This is a G to A transition in exon 6 that results in a substitution of asparagine for aspartic acid at residue 250. Using in vitro site-directed mutagenesis, we have confirmed that this mutation causes a catalytically defective LPL protein. In addition, the Asp250----Asn mutation was also found on the same haplotype in an LPL-deficient patient of Dutch ancestry, suggesting a common origin. This mutation alters a TaqI restriction site in exon 6 and will allow for rapid screening in patients with LPL deficiency.

Amino Acid Sequence↗
PubMed1992

Prevalence, geographical distribution and genealogical investigations of mutation 188 of lipoprotein lipase gene in the French Canadian population of Québec.

Familial lipoprotein lipase deficiency (FLD) is of particular interest to the French Canadian population of Québec since the largest concentration of homozygotes and carriers of this genetic disease in the world resides in this area. We have previously described a missense mutation (M-188) in the lipoprotein lipase (LPL) gene which was present in FLD patients belonging to different ancestries, including a number of French Canadians (Monsalve MV et al. J Clin Invest 1990: 86: 728-734). In the present report, we show that this mutation, although found in largest absolute numbers among French Canadians as compared to other groups in the world, accounts for only a small proportion (24%) of all the LPL mutant alleles in this population. The M-188 occurs either in the homozygote state or as a compound heterozygote with another LPL mutation. Analysis of geographic distribution indicates that the M-188 is more prevalent in western Québec, with the highest carrier rate in the Mauricie region. Genealogical reconstruction leads to the recognition of four founders for M-188, all emigrants from France to Québec in the 17th century.

Base Sequence↗
PubMed1992

Occlusion and narrowing of the pharyngeal airway in obstructive sleep apnea: evaluation by ultrafast spoiled GRASS MR imaging.

Morphologic abnormalities of the pharyngeal airway are frequently found in patients with obstructive sleep apnea. These structural alterations in the pharyngeal airway can be detected in awake patients by using rapid imaging techniques. Ten patients with clinically proved obstructive sleep apnea had ultrafast spoiled gradient-recalled acquisition in the steady state (GRASS) MR imaging of the pharyngeal airway to determine the presence of occlusions and/or narrowings. Twelve sequential images were obtained at one midsagittal plane and at eight transverse planes through the pharyngeal airway. The scans were obtained at the rate of one image per 1.04 sec while the patient was breathing quietly. Occlusions or narrowings of the pharyngeal airways were detected on MR images in all patients. The site(s) of the occlusions and the site(s) and extent of the narrowings varied. Six patients had occlusions and four had narrowings of one or more sites. This study shows that ultrafast spoiled GRASS MR imaging can be used to evaluate patients with obstructive sleep apnea during tidal breathing and is useful for determining the presence of occlusions and narrowings of the pharyngeal airway.

Adult↗
PubMed1992

Adipose cell size and distribution in familial lipoprotein lipase deficiency.

To determine the effect of lipoprotein lipase deficiency on the size distribution of fat cell populations in human adipose tissues, abdominal and femoral subcutaneous fat tissue biopsies were obtained from seven patients affected by familial hyperchylomicronaemia. These patients were characterized by massive accumulation of chylomicrons in the fasting state due to defective catabolism of plasma triglyceride-rich lipoproteins. They had no post-heparin plasma lipoprotein lipase activity and their fat tissues were deficient in lipoprotein lipase activity. The size distribution of adipocytes examined by scanning electron microscopy were similar to distributions observed in control subjects. Patient fat cell diameters were not statistically different from control fat cells obtained from subjects of similar body mass index. Mature fat cells contributed to 99% of the total fat tissue mass in lipoprotein lipase deficiency. Normal adiposity in lipoprotein lipase deficiency can thus be attributed to mature adipocytes and not to hyperplastic growth of immature fat cells. It is concluded that normal adipose tissue homeostasis is maintained in these patients in spite of the deficiency in lipoprotein lipase activity.

Adipose Tissue↗
PubMed1992

Genetic epidemiology of lipoprotein lipase deficiency in Saguenay-Lac-St-Jean (Québec, Canada).

Familial hyperchylomicronemia due to the lipoprotein lipase (LPL) activity deficiency (Type I hyperlipoproteinemia) is an autosomal recessive disorder with a prevalence estimated at one case per million. Thirty-four type I individuals are known in Saguenay-Lac-St-Jean (SLSJ), a geographically isolated region of Quebec. The prevalence of type I and LPL deficient heterozygote in this region was estimated at 1/6382 and 1/46 inhabitants respectively. The mean inbreeding coefficient was slightly elevated in the type I group compared with three control groups. The mean kinship coefficient was 15.1 times higher in the type I group than in the control groups. The high prevalence of type I in SLSJ appears to be the result of the emigration of carriers of LPL deficiency from Charlevoix, another isolated region of quebec to the SLSJ region. Endogamy also played a crucial role in increasing the prevalence of type I in SLSJ.

Child↗
PubMed1991

A mutation in the human lipoprotein lipase gene as the most common cause of familial chylomicronemia in French Canadians.

BACKGROUND: Lipoprotein lipase hydrolyzes the triglyceride core of chylomicrons and very-low-density lipoproteins and has a crucial role in regulating plasma lipoprotein levels. Deficiencies of lipoprotein lipase activity lead to aberrations in lipoprotein levels. Worldwide, the frequency of lipoprotein lipase deficiency is highest among French Canadians. We sought to determine the molecular basis of the disorder in this population. METHODS: The entire coding sequence of the lipoprotein lipase gene from one French Canadian patient was amplified by the polymerase chain reaction and sequenced. Exon 5 from 36 other French Canadian patients was amplified and analyzed by dot blot hybridization with allele-specific oligonucleotides. RESULTS: Sequence analysis revealed a missense substitution of leucine (CTG) for proline (CCG) at residue 207 in exon 5. This mutation was found on 54 of the 74 mutant alleles (73 percent) in the patients. Studies of site-directed in vitro mutagenesis have confirmed that this mutation generates inactive lipoprotein lipase and is the cause of lipoprotein lipase deficiency. CONCLUSIONS: We have identified a missense mutation at residue 207 of the lipoprotein lipase gene that is the most common cause of lipoprotein lipase deficiency in French Canadians. This mutation can be easily detected by dot blot analysis, providing opportunity for definitive DNA diagnosis of the disorder and identification of heterozygous carriers.

Base Sequence↗
PubMed1991

Founder effect in familial hyperchylomicronemia among French Canadians of Quebec.

Familial hyperchylomicronemia has reached a high prevalence in the French Canadian population of eastern Quebec. The birth places of 58 carriers identified through the birth of one affected child clustered in three regions. The genealogies of these 58 individuals showed that no founder was common to all of them. Three sets of founders were found, one for each region, with little overlapping between two regions. These results strongly suggest that more than one mutation, introduced by the French migrants in the 17th century, are segregating in the French Canadian population. Perche, a region situated between Paris and Normandy, appeared to be the most likely putative center of diffusion of at least one mutation in the lipoprotein lipase gene segregating in the modern-day French Canadian population of Quebec.

France↗