151 research outputs found
Haplotype diversity and linkage disequilibrium at human G 6 PD recent origin of alleles that confer malarial resistance
No full textThe frequencies of Low-activity alleles of glucose-6-phosphate dehydrogenase in humans are highly correlated with the prevalence of malaria. These "deficiency" alleles are thought to provide reduced risk from infection by the Plasmodium parasite and are maintained at high frequency despite the hemopathologies that they cause. Haplotype analysis of "A-" and "Med" mutations at this Locus indicates that they have evolved independently and have increased in frequency at a rate that is too rapid to be explained by random genetic drift. Statistical modeling indicates that the A- allele arose within the past 3840 to 11,760 years and the Med allele arose within the past 1600 to 6640 years. These results support the hypothesis that malaria has had a major impact on humans only since the introduction of agriculture within the past 10,000 years and provide a striking example of the signature of selection on the human genome
Diabetes mellitus and optic atrophy: A study of Wolfram syndrome in the Lebanese population
No full textWolfram syndrome (WFS) is a rare hereditary neurodegenerative disorder also known as DIDMOAD (diabetes insipidus, diabetes mellitus, optic atrophy, and deafness). WFS seems to be a heterogeneous disease that has not yet been fully characterized in terms of clinical features and pathophysiological mechanisms because the number of patients in most series was small. In this study we describe 31 Lebanese WFS patients belonging to 17 families; this, to our knowledge, is the largest number of patients reported in one series so far. Criteria for diagnosis of WFS were the presence of insulin-dependent diabetes mellitus and optic atrophy unexplained by any other disease. Central diabetes insipidus was found in 87percent of the patients, and sensorineural deafness confirmed by audiograms was present in 64.5percent. Other less frequent features included neurological and psychiatric abnormalities, urodynamic abnormalities, limited joint motility, cardiovascular and gastrointestinal autonomic neuropathy, hypergonadotropic hypogonadism in males, and diabetic microvascular disease. New features, not reported in previous descriptions, such as heart malformations and anterior pituitary dysfunction, were recognized in some of the patients and participated in the morbidity and mortality of the disease. Genetic analysis revealed WFS1 gene mutations in three families (23.5percent), whereas no abnormalities were detected in mitochondrial DNA. In conclusion, WFS is a devastating disease for the patients and their families. More information about WFS will lead to a better understanding of this disease and hopefully to improvement in means of its prevention and treatment.ALDENHOVEL HBG, 1991, NEUROPEDIATRICS, V22, P103; Al-Sheyyab M, 2001, EUR J PEDIATR, V160, P243, DOI 10.1007-s004310000704; BARRETT TG, 1995, LANCET, V346, P1458, DOI 10.1016-S0140-6736(95)92473-6; Barrett TG, 2000, J MED GENET, V37, P463, DOI 10.1136-jmg.37.6.463; Barrientos A, 1996, AM J HUM GENET, V58, P963; Barrientos A, 1996, J CLIN INVEST, V97, P1570, DOI 10.1172-JCI118581; Baz P, 1999, DIABETES CARE, V22, P1376; Bekir NA, 2000, ACTA OPHTHALMOL SCAN, V78, P480, DOI 10.1034-j.1600-0420.2000.078004480.x; BUNDEY S, 1992, J INHERIT METAB DIS, V15, P315, DOI 10.1007-BF02435965; Collier DA, 1996, AM J HUM GENET, V59, P855; COX RW, 1993, DIABETES CARE, V16, P662; CURADO FJA, 2000, ACTAS UROL ESP, V24, P504; El-Shanti H, 2000, AM J HUM GENET, V66, P1229, DOI 10.1086-302858; Evans KL, 2000, AM J MED GENET, V96, P158, DOI 10.1002-(SICI)1096-8628(20000403)96:2158::AID-AJMG63.0.CO;2-8; Genis D, 1997, ACTA NEUROPATHOL, V93, P426; Gomez-Zaera M, 2001, MOL GENET METAB, V72, P72, DOI 10.1006-mgme.2000.3107; GUNN T, 1976, J PEDIATR, V89, P565, DOI 10.1016-S0022-3476(76)80387-3; Gupta K L, 1994, J Assoc Physicians India, V42, P831; Hardy C, 1999, AM J HUM GENET, V65, P1279, DOI 10.1086-302609; HOFFMANN S, 1997, GENOMICS, V39, P8; HOMAN MR, 1987, DIABETES CARE, V10, P664; Inoue H, 1998, NAT GENET, V20, P143, DOI 10.1038-2441; Kato T, 2001, NEUROSCI RES, V40, P105, DOI 10.1016-S0168-0102(01)00221-8; KINSLEY BT, 1995, DIABETES CARE, V18, P1566, DOI 10.2337-diacare.18.12.1566; Krittiyawong Sirinate, 2000, Journal of the Medical Association of Thailand, V83, P1283; Krolewski AS, 1996, ENDOCRIN METAB CLIN, V25, P217, DOI 10.1016-S0889-8529(05)70322-4; LEIVASANTANA C, 1993, REV NEUROL, V149, P26; LIM M C L, 1990, Annals Academy of Medicine Singapore, V19, P548; Middle F, 2000, AM J MED GENET, V96, P154, DOI 10.1002-(SICI)1096-8628(20000403)96:2154::AID-AJMG53.0.CO;2-F; Ohata T, 1998, HUM GENET, V103, P470, DOI 10.1007-s004390050852; POLYMEROPOULOS MH, 1994, NAT GENET, V8, P95, DOI 10.1038-ng0994-95; ROCCHINI AP, 1995, MOSS ADAMS HEART DIS, P43; Sam W, 2001, CLIN GENET, V59, P136, DOI 10.1034-j.1399-0004.2001.590214.x; Seshiah V, 1987, J Assoc Physicians India, V35, P528; SOLIMAN AT, 1995, ARCH DIS CHILD, V73, P251; Swift M, 2000, BIOL PSYCHIAT, V47, P787, DOI 10.1016-S0006-3223(00)00244-4; SWIFT RG, 1990, LANCET, V336, P667, DOI 10.1016-0140-6736(90)92157-D; Swift RG, 1998, MOL PSYCHIATR, V3, P86, DOI 10.1038-sj.mp.4000344; Takeda K, 2001, HUM MOL GENET, V10, P477, DOI 10.1093-hmg-10.5.477; Tanizawa Y, 2000, Rinsho Byori, V48, P941; Tekgul S, 1999, J UROLOGY, V161, P616, DOI 10.1016-S0022-5347(01)61982-7; Tessa A, 2001, Hum Mutat, V17, P348, DOI 10.1002-humu.32; Torres R, 2001, MOL PSYCHIATR, V6, P39, DOI 10.1038-sj.mp.4000787; Wolfram D. J., 1938, MAYO CLIN P, V13, P71557565
Immune response to and pathogenic mechanisms of contagious bovine pleuropneumonia infection: investigation of the importance of the capsular polysaccharide and assessment of its vaccine potential
No full textMycoplasma mycoides subsp. mycoides small colony type {MmmSC) is the
causative agent of contagious bovine pleuropneumonia (CBPP), a major disease of
cattle in Africa for which current vaccines exhibit a poor efficacy. MmmSC possesses
a capsular polysaccharide (CPS) believed to be an important virulence factor.
Antibodies directed against CPS are bactericidal in an in vitro growth inhibition test
(GIT). Therefore, CPS is a good vaccine candidate.The aim of this thesis was to investigate the vaccine potential of MmmSC
CPS.Before using CPS as a vaccine, the immunogenic structure of CPS needed to
be studied. MmmSC strains were tested with rabbit antisera (raised against different
MmmSC strains) in a GIT. The results showed that CPS was conserved between the
strains. Purified CPS from different MmmSC strains were then investigated with
monoclonal antibodies (mAbs) in an enzyme linked immunosorbent assay (ELISA).
It appeared that CPS from all the strains were recognised by the mAbs, except the
strain PG1 that had a low signal with two of the mAbs. GIT was used with mAbs that
recognised MmmSC CPS to test their growth inhibiting (GI) activity; all of the mAbs
used in the GIT were bactericidal.The specificity of these mAbs was then investigated, using an ELISA, against
other mycoplasmas, Mycoplasma mycoides subsp. mycoides large colony and
Mycoplasma mycoides subsp. capri. The results obtained suggested that the mAbs
recognised at least three different epitopes on CPS.A competitive ELISA was performed to clarify the number of epitopes that
these mAbs recognised. No conclusion could be drawn from this experiment since
the results were unclear.Since antibodies to CPS are bactericidal in vitro, this suggested they were
protective against MmmSC. Passive immunisation of mice with a bactericidal mAb
directed against CPS was used to investigate the protective efficacy of anti-CPS
antibodies in vivo. After injection with the antibody, mice were challenged with an
MmmSC strain. The incidence and the duration of mycoplasmaemia were used to
assess the protection given by this antibody. No significant difference could be seen
between mice passively immunised with anti-CPS antibody and the control group,
suggesting that a bactericidal antibody was not protective in vivo in mice against
challenge with MmmSC.The type of immune response to CPS was examined in three groups of cattle:
M/nmSC-intubated animals, CBPP-vaccinated and unvaccinated animals in contact
with MwrzSC-intubated cattle. The results showed that only a quarter of CBPPvaccinated cattle had an immune response against CPS. The immune response
against CPS in the three different groups was of IgM type even after a second
exposure to the pathogen where it could have been expected an IgG type immune
response.The lack of immune response to CPS in cattle might be due to cross-reactions
with bovine lung. Cross-reactions between bovine lung and MmmSC CPS were
confirmed by western-blot with anti-MwwSC or anti-CPS sera from rabbits, mice
and mAbs. It was not possible to know whether antibodies recognising both CPS and
bovine lung were present in anti-AfrwwSC cow sera because of a background signal
due to the secondary antibody specific for cow immunoglobulins.To minimise the cost of CPS vaccine production, polysaccharides from other
sources could be used as a vaccine. A western-blot was then performed to examine
the cross-reactions between MmmSC CPS and carbohydrates from cereals with
A/mmSC-infected cow sera, MmmSC-immunised rabbit sera and mAbs. The results
showed that CPS shared epitopes with the polysaccharides from the cereals used in
this experiment
Development of a Be-7 beam: Techniques for the ionization of radioactive metallic elements (abstract)
No full textDesign study of a 17.3 GHz electron cyclotron resonance (ECR) ion source at Louvain-la-Neuve
No full textTracking and orbit determination performance of the GRAS instrument on MetOp-A
No full textThe global navigation satellite system receiver for atmospheric sounding (GRAS) on MetOp-A is the first European GPS receiver providing dual-frequency navigation and occultation measurements from a spaceborne platform on a routine basis. The receiver is based on ESA’s AGGA-2 correlator chip, which implements a high-quality tracking scheme for semi-codeless P(Y) code tracking on the L1 and L2 frequency. Data collected with the zenith antenna on MetOp-A have been used to perform an in-flight characterization of the GRAS instrument with focus on the tracking and navigation performance. Besides an assessment of the receiver noise and systematic measurement errors, the study addresses the precise orbit determination accuracy achievable with the GRAS receiver. A consistency on the 5 cm level is demonstrated for reduced dynamics orbit solutions computed independently by four different agencies and software packages. With purely kinematic solutions, 10 cm accuracy is obtained. As a part of the analysis, an empirical antenna offset correction and preliminary phase center correction map are derived, which notably reduce the carrier phase residuals and improve the consistency of kinematic orbit determination results.Delft Institute of earth Observation and Space SystemsAerospace Engineerin
Preparation of Highly Enriched 17-O Samples for Neutron Induced Reaction Studies.
No full textAbstract not availableJRC.D - Institute for Reference Materials and Measurements (Geel
- …
