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Biomedical subjects

J Leman

Publications and source records attributed to J Leman.

15 recordsLinked to original sources
PubMed2004

Screening of SLC26A4 (PDS) gene in Pendred's syndrome: a large spectrum of mutations in France and phenotypic heterogeneity.

Sensorineural hearing defect and goiter are common features of Pendred's syndrome. The clinical diagnosis of Pendred's syndrome remains difficult because of the lack of sensitivity and specificity of the thyroid signs. The identification of PDS as the causative gene allowed molecular screening and enabled a re-evaluation of the syndrome to identify potential diagnostic characteristics. This report presents the clinical and genotypic findings of 30 French families, for whom a diagnosis of Pendred's syndrome had been made. Twenty-seven families had at least one mutated allele. Twenty-eight different mutations were identified, 11 of which had never been previously reported. The main clinical characteristics were: early hearing loss, fluctuation in terms of during deafness evolution, and the presence of an enlarged vestibular aqueduct.

Adolescent↗
PubMed2003

A Crohn's disease-associated insertion polymorphism (3020insC) in the NOD2 gene is not associated with psoriasis vulgaris, palmo-plantar pustular psoriasis or guttate psoriasis.

A C-insertion polymorphism in the NOD2 gene (3020insC) on chromosome 16 is a rare mutation associated with Crohn's disease. Crohn's disease and psoriasis are more commonly observed together than expected by chance. Furthermore a susceptibility locus for psoriasis has been identified on chromosome 16q which overlaps the recently identified susceptibility locus for Crohn's disease. Thus, NOD2 may potentially be important as a candidate susceptibility gene for psoriasis. We tested this hypothesis by genotyping psoriasis patients for the C-insertion polymorphism using the Taqman ABI 7700 sequencing system. No statistically significant differences were observed between psoriasis vulgaris (n = 216), palmo-plantar pustular psoriasis (PPP) (n = 100), guttate psoriasis (n = 118) and the control group (n = 283). In both patient and control groups, no mutant homozygotes were observed and approximately 4% were heterozygotes. This particular insertion mutation in the NOD2 gene does not appear to contribute to the genetic susceptibility of psoriasis vulgaris, PPP or guttate psoriasis. However, other mutations exist in the NOD2 gene, which may potentially have a role in psoriasis susceptibility.

Adolescent↗
PubMed2001

Psoriasis in children: a guide to its diagnosis and management.

Psoriasis often presents in childhood. The diagnosis may be challenging if the disease is mild or the presentation is atypical. All of the forms recognised in adults are encountered in childhood (plaque, guttate, erythrodermic and pustular). Guttate and flexural forms are particularly common in children. Successful management requires education of the child and parents regarding the course of the disease and treatment options. Environmental triggers should be sought out and eliminated where possible. Most patients respond to topical treatment with emollients, coal tar, anthralin (dithranol) or calcipotriol. Treatment is tailored according to patient age, extent and distibution of psoriasis. For those who fail to respond, daycare or inpatient care is appropriate. Phototherapy with UVB may be combined with topical agents. Systemic therapy is required in a minority, usually those with resistant or erythrodermic disease, pustular psoriasis and arthropathic psoriasis. Retinoids are probably the systemic agent of choice. There are few data regarding the use of methotrexate or cyclosporin in childhood psoriais.

Adrenal Cortex Hormones↗
PubMed2001

Effect of environmental factors on the droplet size of o/w emulsion stabilised by beta-lactoglobulin.

The effect of environmental factors (protein concentration, pH, ionic strength) on emulsification properties of beta-lactoglobulin (beta-Lg) was analysed. The protein was obtained from phospholipoprotein-free whey 25-fold concentrated by ultrafiltration (10 kDa cut off) after precipitation of alpha-lactalbumin (alpha-La) with 6% trichloroacetic acid. The Sauter diameter D(vs) of oil droplets in the emulsion stabilised by beta-Lg was found to increase with increases in the protein concentration in the range of 0.5 to 2.0% and medium acidity in the pH range of 5.0 to 7.0. An increase in ionic strength in the range of 0 to 100 mM caused that the emulsification properties of the protein worsened as compared with control emulsion.

Cheese↗
PubMed2001

Coalescence stability of alpha-lactalbumin-stabilised emulsion.

The effects of acidity (pH 5.0 to 7.0) and protein concentration (0.5 to 2.0%) on coalescence stability of o/w emulsion stabilised by alpha-lactalbumin (alpha-La), that was salted out from rennet whey with 7% NaCl at pH 2.0, were studied Irrespective of pH and alpha-La concentration, the Sauter diameter (D(vs)) of an oil droplet was found to increase on storing the emulsion for 4 h at room temperature and the conditions preventing from creaming and accelerating destabilisation of the emulsion. The effect of pH on emulsion coalescence stability was greater than that of protein concentration.

Dose-Response Relationship, Drug↗
PubMed1989

Surface activity, film formation, and emulsifying properties of milk proteins.

This overview indicates that simple, reliable standardized methods for measuring emulsifying activity and for determining ES are not yet available. One of the major shortcomings of most of the current methods is the inability to detect very small fat globules (less than 0.5 micron), which may be very important in stable emulsions. Several of the methods are time consuming and destructive. To minimize the time required to evaluate emulsions, techniques that monitor instability under the influence of accelerated aging (increased temperature and gravitational field) have been used with varying degrees of success. These methods, e.g., centrifugation, are useful, but processes occurring during centrifugation or heating may not be characteristic of those occurring in a stored emulsion. Generally, there is no method that simultaneously determines changes in emulsions due to the aggregation coalescence, flocculation, creaming, of the droplets and/or oiling off. No single criterion of emulsion instability is sufficient to characterize all the changes occurring in the system. A nonintrusive technique that can monitor dynamic changes in emulsions is needed. Ideally, it should be simple, rapid, inexpensive, and applicable to both diluted and concentrated emulsions. Scientists must continue research to develop such a standard universal method for determining ES, because data from different laboratories cannot currently be validly compared. Reliable methods are also required to elucidate relationships between the physical properties of proteins as emulsifiers and their performance in food emulsions. There is a need for opportunities for systematic research to determine the interfacial behavior of food emulsifiers, particularly food proteins. Research to describe the kinetics and thermodynamics of adsorption at an interface, the extent of unfolding, the degree of packing and polypeptide interactions in an interface during film formation, and information concerning the physical and mechanical properties of interfacial films is needed to describe emulsifying behavior of different proteins. The effects of components in the continuous and discontinuous phase, parameters of manufacture, and interactions between different types of surface-active materials that occur in food need to be studied.

Emulsions↗
PubMed1988

Bone mineral content in normally menstruating women with hyperprolactinaemia.

Decreased bone density has been reported in women with hyperprolactinaemia due to pituitary tumours. We identified a number of seemingly healthy women with hyperprolactinaemia, i.e. a serum prolactin concentration exceeding 500 mU/l (25 micrograms/l) on three occasions, during a study in 1980/1981 of a representative population sample of greater than 1,400 women in seven different age strata (range 26-72 years). We compared vertebral bone mineral content and bone mineral areal content in 5 hyperprolactinaemic normally menstruating 50-year-old women with that of 6 controls matched for age and menstrual status but found no difference. Since the degree of prolactin elevation was similar in our study group to that previously reported for hyperprolactinaemic subjects with pituitary tumours and the time of exposure to raised hormone concentration appears to be of the same magnitude, other hormonal changes than hyperprolactinaemia per se seem to be the cause of low bone mineral content in women with hyperprolactinaemia and amenorrhoea.

Alkaline Phosphatase↗
PubMed1987

Metachromasia of 3-amino-9-ethylcarbazole (AEC) and its prevention in immunoperoxidase techniques.

3-Amino-9-ethylcarbazole (AEC) used as chromogen in immunoperoxidase techniques normally has an intense, red colour. However, as an inconstant phenomenon, a pale yellowish-green reaction product severely impairing the evaluation can be observed. In order to circumvent this undesired effect, factors such as tissue fixative, proteolytic digestion, antibody concentrations and incubation time of the primary antibody were analyzed. The most important factor inducing a change in colour is probably the inadequately high local peroxidase concentration arising as the consequence of high amounts of bound primary antibody. This high enzyme concentration might cause metachromasia of AEC by producing the yellowish-green quinone-di-imine form of the substrate. As could be shown by spectrophotometry in test tube experiments, AEC metachromasia was proven to be enzyme dependent. Thus, the best way to trigger the local enzyme concentration on a tissue section to adequate levels appears to be the dilution of the primary antibody.

Carbazoles↗