Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 66
Filtrar
1.
Animal ; 15(9): 100334, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34392194

RESUMO

In a context of evolving concern over housing conditions of farmed rabbits, we developed a housing system that allows access to an outdoor area. The aim was to study the health status, growth and behaviour of rabbits raised at two stocking densities with access to a paddock, or not. We distributed 299 weaned rabbits in four groups (YH: 100, NH: 99, YL: 50 and NL: 50) using a 2 × 2 factorial design including access (Y: yes) or not (N: not) to a 23 m2 paddock and the indoor stocking density (H, high: 17 or L, low: 9 rabbits/m2). We measured the growth and health status of each animal weekly for 42 days (from 31 to 73 days of age) and performed reactivity tests to a new environment, a human and new object. We also assessed the rabbits' behaviour at days 26 and 40 by doing a visual scan of each animal at regular time intervals. Our results showed that stocking density had no effect on mortality, but mortality tended to increase with outdoor access from 3.0% to 7.0% (P < 0.10). Although the stocking density had no effect on average daily gain, it was higher in rabbits in the N group than in the Y group (+3.6 g/day; P < 0.05). Rabbits entered the paddocks for the first time in less time at the beginning of the trial (50 s at day 3 vs 10 min at day 31; P < 0.001). The proportion of rabbits outside after 20 min of the new environment test was higher among rabbits in the L group than in the H group (+24% points at day 3 and +11% points at day 20; P < 0.001). Regardless of the stocking density, more rabbits in the N group touched the experimenter's hand (16% vs 27%; P < 0.05) and the new object (34% vs 20%; P < 0.05) than rabbits in the Y group. Inactivity was more frequent in rabbits inside the pens than in the paddocks (70.0% vs 34.2% at days 26 and 40; P < 0.05). Locomotion was more frequent in the paddocks than in the indoor pens (20.0% vs 7.2% at days 26 and 40; P < 0.05). The stocking density did not affect the behavioural traits measured. In conclusion, providing rabbits access to a paddock could allow them to fulfil some natural behaviours but slightly reduced their growth.


Assuntos
Comportamento Animal , Abrigo para Animais , Animais , Locomoção , Fenótipo , Coelhos , Desmame
2.
Animal ; : 1-9, 2020 Feb 13.
Artigo em Inglês | MEDLINE | ID: mdl-32051049

RESUMO

In young rabbit, digestive disorders are frequently observed around weaning. Stimulating the onset of feed intake in the suckling rabbit might be a way to promote gut health. The aim of this study was to determine the rabbit's acceptability for different feed presentations and its preferences for flavours at an early stage of life. Two trials were conducted to evaluate the effects of physical form and flavouring on creep feed attractiveness. All the diets tested were provided in the nest from 3 to 17 days, and the daily intake per litter was recorded as of 8 days of age. In the first trial, five feed presentations were tested separately (n = 60 litters). Three dry presentations were chosen: commercial pellet (P), crumb from commercial pellet (cP) and crumb from beet pulp pellet (cBP). Hydrated feeds were also provided with either raw fodder beetroot (B) or a semi-solid feed in agar gel form produced with fodder beetroot juice and pulp (gB). In the second trial, double-choice tests were performed on four feed gels (n = 72 litters), leading to six comparison treatments. These agar gels were made of pellet mash without or with a sensory additive: one non-odorised control gel and three gels with 0.20% banana flavour, 0.06% red berry flavour and 0.10% vanilla flavour, respectively. In the first trial, kits ate more gB in fresh matter than other feed presentations (P < 0.001), with a total intake of 7.0 ± 1.8 g/rabbit from 8 to 17 days. In DM, the total consumption of pellets P (1.6 ± 0.4 g of DM/rabbit) was the highest together with the gB form (1.4 ± 0.4 g of DM/rabbit), whereas cBP was barely consumed (0.3 ± 0.1 g of DM/rabbit). Gel feed supplemented with vanilla was slightly more consumed than other flavoured and non-odorised gels (relative consumption of 57% when compared to control gel; P = 0.001). The gel feed intake was independent of the milk intake but was correlated with the litter weight at 3 days (r = 0.40, P < 0.001). In both trials, rabbit growth before and after weaning was not affected by the type of creep feed provided. Our results confirmed that providing creep feed promotes the solid intake of rabbits at early stages. Gel feed form motivated rabbits to eat and vanilla flavour supplementation increased the feed palatability. Those creep feed characteristics should be explored further for seeking effective stimulation of the onset of the feed intake in suckling rabbit.

3.
Food Chem ; 190: 164-172, 2016 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-26212956

RESUMO

The influence of protein and/or fibre enrichment on the nutritional properties of biscuits was studied in terms of proteolysis and amylolysis. Biscuits were digested using a multi-compartmental and dynamic system that simulates the main physiological digestive functions of the upper tract of healthy adult humans: the TIM-1. A control biscuit and three biscuits enriched in proteins and/or fibres were digested under the same conditions. Samples were collected in each compartment of the TIM-1 (stomach, duodenum, jejunum and ileum) at different times of digestion and analysed in terms of proteolysis and amylolysis. Results indicate that both formulation and processing impacted the digestive fate of the biscuits. Incorporating proteins or fibres in biscuits lowered or delayed proteolysis. Moreover a protein-plus-fibre additional or synergic effect was observed. Biscuits enriched in proteins and/or fibres displayed a higher amylolysis degree than the control biscuit, probably due to lower starch amounts and higher gelatinization degrees.


Assuntos
Fibras na Dieta/análise , Amido/química , Digestão , Técnicas In Vitro , Amido/metabolismo
5.
Food Chem ; 182: 55-63, 2015 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-25842308

RESUMO

The effects of biscuit composition on the viscosity generated during digestion were investigated. A control biscuit, one with proteins, one with fibres, and one with both proteins and fibres were digested under the same conditions, using the TNO intestinal model (TIM-1). The TIM-1 is a multi-compartmental and dynamic in vitro system, simulating digestion in the upper tract (stomach and small intestine) of healthy adult humans. Digesta were collected at different times, in the different compartments of the TIM-1 (stomach, duodenum, jejunum and ileum) and viscosity was measured with a dynamic rheometer. Results showed a marked effect of biscuit composition on chyme viscosity. Highest viscosity was obtained with biscuits containing viscous soluble fibres, followed by those enriched in both proteins and fibres, then by protein-enriched and control biscuits. The viscosity was maintained throughout the gut up to the ileal compartment. A prediction of the evolution of the chyme viscosity in each compartment of the TIM-1 was built, based on model curves describing the evolution of the viscosity as a function of biscuit concentration, and on dilution factors measured by spectrophotometry on a blank digestion.


Assuntos
Pão/análise , Fibras na Dieta/análise , Digestão/fisiologia , Humanos , Técnicas In Vitro , Viscosidade
6.
J Fr Ophtalmol ; 36(10): 820-9, 2013 Dec.
Artigo em Francês | MEDLINE | ID: mdl-24119454

RESUMO

Cavernous hemangioma is the most frequent benign orbital tumor in adults. The purpose of this study was to examine its clinical features, to define surgical indications, and to determine the roles of the various surgical approaches praticed in ophthalmology: transconjunctival (increasingly utilized), anterior transcutaneous, and lateral orbitotomy. The records of all patients treated for orbital cavernous hemangioma (OCH) since 2004 at the Fondation Rothschild (Paris, France) were retrospectively reviewed. Forty-three patients were treated for orbital cavernous hemangioma. Fifty-eight percent were women, mean age 50.2; 79 % of the tumors were intraconal. Among those patients, 36 underwent surgical removal, 5 were followed periodically, and 2 were lost to follow-up. The main surgical indications were: optic nerve compression (26 patients), proptosis (24 patients) and diplopia (3 patients). Transconjunctival, anterior transcutaneous and Kronlein approaches were used in 16, 12 and 4 patients respectively. Four patients had intrapalpebral hemangiomas easily reached transcutaneously. Two patients demonstrated transient partial 3rd nerve palsy (one with the lateral orbitotomy approach and one with the transconjunctival approach), one patient with the lateral orbitotomy approach developed a palsy of the superior branch of the 3rd nerve, and one patient with the transcutaneous anterior approach developed mydriasis. Surgical excision of OCH's is required in the presence of clinical complications. The transconjunctival approach is a safe technique which can lead to complete resection of the tumor in most cases.


Assuntos
Hemangioma Cavernoso/cirurgia , Procedimentos Cirúrgicos Oftalmológicos/métodos , Neoplasias Orbitárias/cirurgia , Adulto , Idoso , Estudos de Coortes , Túnica Conjuntiva/cirurgia , Feminino , Hemangioma Cavernoso/epidemiologia , Humanos , Masculino , Pessoa de Meia-Idade , Órbita/cirurgia , Neoplasias Orbitárias/epidemiologia , Estudos Retrospectivos
7.
Biopolymers ; 59(3): 131-44, 2001 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-11391563

RESUMO

Using a multitechnique approach, two temperature domains have been identified in agarose gelation. Below 35 degrees C, fast gelation results in strong, homogeneous and weakly turbid networks. The correlation length, evaluated from the wavelength dependence of the turbidity, is close to values of pore size reported in the literature. Above 35 degrees C, gelation is much slower and is associated with the formation of large-scale heterogeneities that can be monitored by a marked change in the wavelength dependence of turbidity and visualised by transmission electron microscopy. Curing agarose gels at temperatures above 35 degrees C, and then cooling them to 20 degrees C, produces much weaker gels than those formed directly at 20 degrees C. Dramatic reductions in the elastic modulus and failure strain and stress are found in this case as a result of demixing during cure. An interpretation, based on the kinetic competition between osmotic forces (in favor of phase separation) and elastic forces (that prevent it) is proposed.


Assuntos
Sefarose/química , Elasticidade , Géis , Cinética , Nefelometria e Turbidimetria , Termodinâmica
8.
Biomacromolecules ; 1(4): 730-8, 2000.
Artigo em Inglês | MEDLINE | ID: mdl-11710204

RESUMO

The current study focuses on the effects of the molecular weight on the mechanical behavior of agarose gels. The small strain rheology and large strain deformation/failure behavior of three different molecular weight agarose gels have been examined, with the results expressed in term of molar concentration. For small deformation strains, the gelation temperature at low concentrations and the critical concentration for gel formation are strongly affected by the molecular weight. In addition, the elasticity of the network is also very sensitive to this parameter. It has been demonstrated that the experimental gelation cure curves can be superimposed on a universal gelation master curve, independent of the cure time. This would indicate self-similarity of the network at different scales, irrespective of concentration. A relationship between the elastic modulus and the molecular weight has been extracted from these results, where the molecular weight dependence exhibits a power law exponent of 2.42. For large deformation strains, the Poisson ratio has been estimated to be 0.5 for each of the agarose types examined, which indicates that these gels are incompressible. The strain at failure is largely dependent on the molecular weight, and is essentially independent of the biopolymer concentration. This result highlights the fact that the strain at failure is sensitive to the connectivity distances in the gel network. However, the failure stress and Young's modulus of agarose gels show a dependence on both concentration and molecular weight. The observations regarding Young's modulus are in good agreement with those found for small deformation strain rheology for the shear modulus. One of the primary advantages of using the lowest molecular weight agarose is that higher molar concentrations can be reached (more molecules per unit volume). However, the mechanical response of agarose gels is very sensitive to the molecular weight at fixed molar concentration, and if the present results are extrapolated to very low molecular weight, it can be suggested that below a limiting molecular weight a percolating network will not be formed, as suggested by the Cascade model (Carbohydr. Polym. 1994, 23, 247-251). This speculation is based on the influence of the "connectivity" at long distances, which influences the strain at failure (when the strain at failure is zero, the system is not connective).


Assuntos
Sefarose/química , Algoritmos , Elasticidade , Géis , Cinética , Peso Molecular , Reologia , Temperatura , Resistência à Tração
9.
Hum Mutat ; 14(6): 502-9, 1999.
Artigo em Inglês | MEDLINE | ID: mdl-10571948

RESUMO

Several human respiratory disorders have been linked to an abnormality of pulmonary surfactant synthesis or turnover. Among those conditions, hereditary deficiency in the hydrophobic surfactant protein B (SP-B) has been recognized as a rare cause of respiratory failure in term newborn infants. Homozygosity for a common mutation (1549C-->GAA, or 121ins2) of the SP-B-encoding gene (SFTPB) results in rapidly fatal respiratory failure, with complete absence of the mRNA and protein observed in lung fluid or biopsy specimens. Hereditary SP-B deficiency is also associated with aberrant processing of proSP-C and deficiency of the active SP-C peptide. In the present study, we characterized the SFTPB gene in an infant with severe unexplained respiratory distress and identified a paternally derived 1549C-->GAA lesion, as well as a hitherto unreported mutation (457delC) inherited from the mother. Analysis of bronchoalveolar lavage fluid demonstrated the complete absence of SP-B. However, unlike previous infants with hereditary SP-B deficiency, proSP-C was processed to the active SP-C peptide, suggesting that the defect in SP-B, rather than SP-C, caused the respiratory distress in this infant. The present findings demonstrate the importance of SFTPB in pulmonary function and support the need for further genotype-phenotype correlations in patients with SP-B deficiency.


Assuntos
Mutação , Proteolipídeos/genética , Surfactantes Pulmonares/genética , Síndrome do Desconforto Respiratório do Recém-Nascido/genética , Sequência de Bases , Líquido da Lavagem Broncoalveolar/química , Primers do DNA/genética , Éxons , Feminino , Mutação da Fase de Leitura , Genótipo , Heterozigoto , Humanos , Recém-Nascido , Masculino , Linhagem , Fenótipo , Proteolipídeos/metabolismo , Surfactantes Pulmonares/metabolismo , Síndrome do Desconforto Respiratório do Recém-Nascido/metabolismo , Deleção de Sequência
10.
Clin Nutr ; 18(3): 159-65, 1999 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-10451473

RESUMO

AIMS: To investigate teicoplanin added to pediatric parenteral nutrition solutions in terms of its stability, its compatibility with parenteral nutrition solution components, and its diffusion through an antibacterial filter material. METHODS: Three binary solutions with and without teicoplanin were studied. Different solution compositions and teicoplanin concentrations were used: A (98.3 +/- 8.2 mg/l), B (116.3 +/- 12.4 mg/l), and C (162.7 +/- 16.2 mg/l). Concentrations of teicoplanin and of solution components, osmolality, and pH of each solution were measured at H0, after 24 h at room temperature, after 24 h at +4 degrees C followed by 24 h at room temperature, and after 144 h at +4 degrees C followed by 24 h at room temperature (H168). Teicoplanin concentrations were also measured before and after passage of each solution through a 0.22 micro filter. RESULTS: Teicoplanin concentrations remained unchanged from H0 to H168 in solutions A (99.6 +/- 8.3 mg/l), B (116.9 +/- 12. 3 mg/l), and C (162.4+12.9 mg/l). During the H0-H168 interval, iron and methionine were the only components that showed significant decreases, which were similar in solutions without teicoplanin [iron, -6.1% (A), -6.8% (B), and -4.5% (C); methionine, -7.3% (A) and -8. 7% (B)] and in those with teicoplanin [iron, -6.2% (A), -7.1% (B), and -4.0% (C, nonsignificant); methionine, -10.5% (A) and -10.7% (B)], indicating that they were not dependent on the presence of teicoplanin. Teicoplanin levels after filtration were identical to prefiltration values in solutions A (86.4 +/- 5.0 vs 89.8 +/- 3.4 mg/l) and B (112.6 +/- 4.3 vs 115.3 +/- 9.0 mg/l) but were 10.0% lower in solution C (161.6 +/- 3.9 vs 145.4 +/- 4.0; P << 0.001). CONCLUSIONS: Teicoplanin can be added to pediatric parenteral nutrition solutions to treat central venous catheter-related infections due to teicoplanin-susceptible organisms since its concentrations and those of solution components remain stable over time.


Assuntos
Antibacterianos/química , Alimentos Formulados/análise , Nutrição Parenteral , Pediatria , Teicoplanina/química , Antibacterianos/administração & dosagem , Criança , Incompatibilidade de Medicamentos , Estabilidade de Medicamentos , Filtração , Alimentos Formulados/normas , Humanos , Infusões Intravenosas , Pediatria/métodos , Teicoplanina/administração & dosagem , Temperatura
11.
Ann Genet ; 42(2): 69-74, 1999.
Artigo em Inglês | MEDLINE | ID: mdl-10434119

RESUMO

van der Woude syndrome (vWS, MIM 119300) is a rare autosomal dominant clefting condition with cardinal features of mucous cysts (lower-lip pits) and clefts to the lip and/or palate. The vWS gene has been assigned to a locus in 1q32-q41 by linkage analysis and physical mapping. We have investigated 5 novel vWS families through probands attended for cleft lip and/or palate repair at the Department of Maxillofacial Surgery of Hôpital Trousseau, Paris, in order to tentatively refine the genetic map of the vWS region in 1q32-q41 and possibly identify unlinked pedigrees. Linkage analysis was carried out to 6 microsatellite markers (D1S249, D1S425, D1S491, D1S205, D1S414, D1S425), yielding a maximum cumulative LOD score of Z = 3.27 at theta = 0.00 for D1S245. The innermost four markers were found to be tightly linked to one another, with no evidence for recombination. Our results support linkage of vWS within a region of tightly linked markers and do not favour locus heterogeneity of the disease trait.


Assuntos
Ligação Genética , Doenças Labiais/genética , Repetições de Microssatélites , Característica Quantitativa Herdável , Mapeamento Cromossômico , Cromossomos Humanos Par 1 , Fenda Labial/genética , Fissura Palatina/genética , Feminino , Genes Dominantes , Humanos , Escore Lod , Masculino , Linhagem , Síndrome
12.
Clin Chem Lab Med ; 37(4): 397-402, 1999 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-10369109

RESUMO

Fragile X syndrome is the most frequent heritable genetic disease involving mental retardation and is usually caused by an expanded CGG repeat in the first exon of the FMR1 gene. Therefore, searching for CGG expansion at the FRAXA locus among the mentally retarded has become a routine investigation in neuro-paediatric practice. Consequently, we have developed a fluorescent PCR-based assay for sizing repeats as an alternative to laborious and time-consuming Southern blot. The procedure utilises a reverse fluorescent labelled primer, and the Expand Long Template PCR system (Roche) with addition of dimethylsulfoxide and 7-deaza-dGTP It allows precise determination of the CGG repeat number in males and females for alleles from normal to premutation size range and detection of full mutations in males. We believe that this PCR protocol, allowing a high sample throughput, is useful for first-line screening among mentally retarded males, possibly complemented by Southern blot analysis to assess the methylation status of large mutated alleles.


Assuntos
Síndrome do Cromossomo X Frágil/diagnóstico , Síndrome do Cromossomo X Frágil/genética , Reação em Cadeia da Polimerase/métodos , Repetições de Trinucleotídeos , Eletroforese em Gel de Poliacrilamida , Testes Genéticos/métodos , Humanos , Deficiência Intelectual/genética
16.
Brain Res ; 769(2): 329-32, 1997 Sep 26.
Artigo em Inglês | MEDLINE | ID: mdl-9374202

RESUMO

Magnesium is important in cerebral function. If there is a deficiency and neurological symptoms accrue, we hypothesised that Mg2+ deficiency causes neurological symptoms by decreasing the level of Mg2+ in cerebral tissue. The content of magnesium was determined in 12 brain structures in magnesium-deficient rats. Experiments were carried out for 40 days in two groups of Wistar male rats made magnesium-deficient (MD) by a well-controlled diet (50 mg of Mg2+/kg of food), and a control group (CG) rats fed normal diet (1 g of Mg2+/kg of food). At the end of the 40 days, the clinical signs of hypomagnesemia were sought in the MD rats and Mg2+ concentration levels were measured in the blood and brain. The results showed variable distribution of Mg2+ in the different brain structures, both in CG and MD rats; in the MD rats there is an important stability of global Mg2+ content of the brain. Although the global values for Mg2+ in the brain did not decline in MD rats, there was a significant decrease in Mg2+ in the brainstem. We conclude that the brain is able to maintain a stable concentration of Mg2+ during chronic hypomagnesemia, but its topographic variations could account for some of neurological signs accompanying this condition.


Assuntos
Encéfalo/metabolismo , Deficiência de Magnésio/metabolismo , Magnésio/metabolismo , Animais , Deficiência de Magnésio/sangue , Masculino , Concentração Osmolar , Ratos , Ratos Wistar , Distribuição Tecidual
17.
Pflugers Arch ; 434(3): 300-5, 1997 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-9178630

RESUMO

Intestinal calcium absorption has been shown to include two processes, a saturable transcellular movement and a non-saturable paracellular pathway. The potential utility of cell monolayers for studying transepithelial intestinal calcium transport has already been demonstrated; however, simultaneous evaluation of the contribution of the saturable transcellular and of the non-saturable paracellular processes to the total transepithelial transport has not yet been attempted. The aim of this study was to investigate the contribution both of transcellular and paracellular transport processes to the total transepithelial calcium transport in two cell culture monolayers. Caco-2 cells and a clone derived from HT-29 cells (HT29-Cl.19A), two cell lines derived from colon adenocarcinomas which are known to be able to exhibit typical enterocytic differentiation, were used. Cell monolayers were grown on a permeable support and used after 15 days of culture when these cells express enterocytic differentiation and high transepithelial resistance. Isotopic transport rate measurements were performed in the absence of a chemical gradient. The paracellular route was evaluated using [3H]mannitol. Calcium and [3H]mannitol transport rates across cell monolayers were not significantly different. Augmentation of calcium uptake by 200 mM sorbitol did not significantly increase calcium or mannitol transepithelial transport; however, calcium accumulation in the cells was increased by about 200%. Modulation of the monolayer permeability by addition of 10 nM vasoactive intestinal polypeptide (VIP) or 0.5 mM carbachol treatment, which respectively increased and decreased the transepithelial resistance, consequently modified calcium and mannitol transport in a parallel manner. Our results show that Caco-2 and HT29-Cl.19A cell monolayers are good models for studying the calcium paracellular transport pathway.


Assuntos
Cálcio/metabolismo , Células CACO-2 , Carbacol/farmacologia , Epitélio/efeitos dos fármacos , Epitélio/metabolismo , Células HT29 , Humanos , Absorção Intestinal , Mucosa Intestinal/metabolismo , Intestinos/efeitos dos fármacos , Transporte de Íons/efeitos dos fármacos , Cinética , Manitol/farmacocinética , Ouabaína/farmacologia , Sódio/farmacologia , Sorbitol/farmacologia , Peptídeo Intestinal Vasoativo/farmacologia
18.
Ann Genet ; 40(3): 185-8, 1997.
Artigo em Inglês | MEDLINE | ID: mdl-9401110

RESUMO

More than 600 mutations have been identified in the Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) gene and are known to cause cystic fibrosis (CF). This large number of mutations makes the search of the molecular defects in CF patients difficult. We have used the techniques of denaturing gradient gel electrophoresis (DGGE) and direct DNA sequencing to detect the mutations in 334 CF chromosomes mostly of French origin. The whole coding sequence of the CFTR gene corresponding to the 27 exons and their exon-intron boundaries was studied. 45 different mutations were identified. This method allowed us to detect the molecular defect in 90.5% of the mutant alleles and to report a novel mutation D979V.


Assuntos
Regulador de Condutância Transmembrana em Fibrose Cística/genética , Fibrose Cística/genética , Adolescente , Criança , Pré-Escolar , Fibrose Cística/diagnóstico , Eletroforese em Gel de Poliacrilamida/métodos , Éxons , Feminino , Humanos , Lactente , Masculino , Pessoa de Meia-Idade , Mutação
19.
Int J Biol Macromol ; 19(3): 213-21, 1996 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-8910062

RESUMO

Bovine beta-lactoglobulin is a globular whey protein that associates partly and reversibly in dimers in the native state. Static and dynamic light scattering techniques have been used to determine the relative amount of monomers and dimers, and to estimate their size and shape in different conditions. The effect of the ionic strength on the dimerisation has been studied at pH 2, where the protein is highly charged. A simple model, taking into account the monomer-dimer equilibrium and virial interactions has been used. The strength of the interactions depends on the amount of added salt, i.e. ionic strength, and influences the dimer dissociation. When the ionic strength decreases, the equilibrium is shifted towards the monomeric form. The dissociation, however, is only complete at very low concentration. The effect of temperature has been studied at pH 7 and low concentration where virial interactions are negligible. The dissociation increases with increasing temperature (5 degrees C - 76 degrees C). At high temperatures, protein-protein aggregation is fast, even at low concentration. The temperature dependence can be described using a simple Van't Hoff model, even at temperatures where aggregation occurs. The ionic strength and temperature dependence both indicate that beta-lactoglobulin solutions have to be considered as a mixture of monomers and dimers.


Assuntos
Lactoglobulinas/química , Concentração de Íons de Hidrogênio , Modelos Químicos , Concentração Osmolar , Conformação Proteica , Espalhamento de Radiação , Temperatura
20.
J Pediatr Gastroenterol Nutr ; 22(3): 284-8, 1996 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-8708882

RESUMO

Twenty-two cases of sucrase-isomaltase deficiency (SID) were observed over a period of 20 years. Since 1977 delay of introduction of sucrose and its decrease in infants' diets have modified the symptomatology. In general, onset of diarrhea has not taken place immediately but 15 days to 2 months after introduction of sucrose. Out of 12 cases with dehydration, five occurred 3 to 7 months after the beginning of sucrose diet. Hypotrophy was not constant (11 of 22 cases), thus diagnosis was delayed in 17 of 22 cases. A yellow complexion due to rising carotene levels in the blood is a striking feature. Because of falsely positive sucrose load tests (four out of 14 nonSID infants) and failure of the hydrogene breath test (one out of five studied cases), disaccharidase determination remains the key to diagnosis. Despite the genetic difference symptoms seem to depend on infant feeding practices.


Assuntos
Erros Inatos do Metabolismo dos Carboidratos/diagnóstico , Complexo Sacarase-Isomaltase/deficiência , Erros Inatos do Metabolismo dos Carboidratos/complicações , Carotenoides/sangue , Pré-Escolar , Consanguinidade , Desidratação/etiologia , Diarreia/etiologia , Dieta , Feminino , Humanos , Lactente , Masculino , Estudos Retrospectivos , Sacarose/administração & dosagem
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...