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Biomedical subjects

D Silvestre

Publications and source records attributed to D Silvestre.

At least 19 recordsLinked to original sources
PubMed2006

Available lysine content in human milk: stability during manipulation prior to ingestion.

UNLABELLED: Available lysine content is an indicator of protein quality and nutritional value of milk. Many studies have examined the effects of extraction, treatment and storage of human milk upon its components, though no references are found regarding the possible changes in milk quality as defined by its content in essential amino acids such as lysine. The present study investigates the available lysine content in human milk and the variations in lysine resulting from milk manipulation as follows: (a) Cold storage (refrigeration at 4 degrees C for 48 hours, and frozen for 15 days at -20 degrees C); (b) Thermal treatment under conditions of low (Holder)(63 degrees C/30 minutes) and high pasteurization (75 degrees C/15 seconds). The results obtained show a decrease in milk lysine concentration after storage in both refrigerated and frozen samples. Pasteurization causes a highly significant loss of available lysine. The lysine losses were greater on applying low pasteurization versus the more gentle conditions of high pasteurization. CONCLUSIONS: While manipulation through cold storage or thermal treatment does not affect the protein content of human milk, its protein quality is modified. When human milk must be subjected to hygienization, it is preferable to apply high temperature treatment (75 degrees C, 15 seconds) than habitual pasteurization (63 degrees C, 30 minutes).

Biological Availability↗
PubMed2006

Bactericidal activity of human milk: stability during storage.

Human milk provides infants with defensive factors against many illnesses. This study aims to analyse global bactericidal activity in fresh human milk and evaluate its stability in relation to milk manipulation and its possible alteration following refrigeration. Nineteen milk samples (mature milk) from 19 healthy women are analysed. Viability testing involving a strain of Escherichia coli NCTC 9111, serovar O111:K58(B4):H- was used to determine the bactericidal effect of human milk. Degree of bacteriolysis is calculated as the difference between E. coli counts in controls and in milk samples, expressed as a percentage of the control sample counts. An evaluation of the effect of refrigeration at 4-6 degrees C after 24, 48 and 72 hours, and at -20 degrees C for seven days on bactericidal capacity is made. Bactericidal activity was detected in all milk samples analysed (77.33 +/- 15.14%). This activity persisted after refrigeration for 48 hours and after freezing for 10 days, but showed a significant decrease after refrigeration for 72 hours. In conclusion, maternal milk has bactericidal capacity, providing defence and protection against infection for newborn infants. This property can be altered during the storage of milk. Consequently, if storage in excess of 48 hours is required, freezing is preferable to refrigeration.

Anti-Bacterial Agents↗
PubMed2001

Copper, iron, and zinc contents in human milk during the first three months of lactation: a longitudinal study.

The aim of the study has been to analyze the evolution of copper, iron, and zinc contents in human milk, from colostrum to the third postpartum month, following a longitudinal design, under specific conditions of sample collection and to apply an analytical procedure previously optimized to reduce any variation outside physiological lactation. The copper, iron, and zinc concentrations in 144 milk samples from 39 healthy puerpera women, were analyzed in five stages by flame atomic absorption spectrometry, following a standardized protocol. Copper presented a gradual decrease from 0.38 mg/L to 0.19 mg/L by the 90th day; the particular analysis from colostrum to transitional milk manifested the following two tendencies. Whereas an increase from 0.19 to 0.42 mg/L was observed in some women, a decrease from 0.53 to 0.45 mg/L was detected in others; therefore, copper presented two significant behaviors in the evolution from colostrum to transitional milk. In both cases, the evaluated changes were significant. The iron content varied from 0.56 to 0.40 mg/L by the 30th day, remaining constant until the first trimester concluded. The average zinc concentration decreased sharply from 7.99 to 3.3 mg/L on d 15; the rate of decrease slowed down gradually until 1.05 mg/L.

Colostrum↗
PubMed1988

A gas chromatographic/mass spectrometric screening, confirmation, and quantification method for estrogenic compounds.

A method is described for the screening, quantification and confirmation of a variety of estronenic substances in animal tissues. A solid-phase extraction technique combined with a liquid/liquid extraction allows for rapid sample preparation and high throughput for the following compounds in bovine liver, muscle and kidney: diethylstilbestrol, dienestrol, hexestrol, zeranol, taleranol, zearalanone, zearalenone, zearalenol, estradiol and estriol. Gas chromatography/mass spectrometry and selected ion monitoring is used for the determination with detection limits ranging from 50 to 150 ppt.

Animals↗
PubMed1981

Asking for a prenatal diagnosis after the birth of a child with Down's syndrome.

Three years ago we undertook, in collaboration with André and Joëlle Boue (Inserm U 73), a research project investigating the psychological aspects of prenatal diagnosis following the earlier birth (and sometimes death) of a child with Down's syndrome. For this study we selected 20 couples who had requested such an examination. These couples present some particularities which justified, in our opinion, a specific study. In a few cases, one of the parents happened to be a carrier of a balanced chromosome translocation, but usually the trisomy was free. Moreover, the mother's age did not increase the risk factor. Our investigation was carried out on the basis of a series of one or several interviews, the man and the woman being seen separately. These unstructured interviews, with the fewest possible questions and interventions on our part, were tape-recorded with the permission of our subjects. We then analyzed the precise content of the typed texts of the these interviews. Two main topics emerged from this analysis: 1) The extreme impact of the birth of a child with Down's syndrome and the place and role of such a child in the family's life, and 2) The relationship between the parents and physician before and after the birth, including the request for a prenatal diagnosis.

Amniocentesis↗
PubMed1980

[Psychological repercussion of hereditary diseases and of their detection (author's transl)].

In an investigation concerning the psychological aspects of prenatal diagnosis, the repercussions of hereditary disease as well as their detection were studied. Analysis of the contents of interviews with the 30 involved couples pointed out the prevalence of imaginary elaborations regarding heredity and its affections and allowed us to examine the function of the secret, which was always present, regardless of the hereditary disease and its means of transmission.

Adult↗
PubMed1978

[Prenatal diagnosis. A psychological study. II. Pregnancy after the age of 40 (author's transl)].

This article, which is the second installment of a study of the psychological aspects of antenatal diagnosis, presents the analysis of interviews with women (and with some of their partners) who were examined because of their age. The characteristics of these "late" pregnancies seem to be the following: 1. The question of a abnormality shifts the emphasis from the child to the pregnancy itself, which is often lived through as something abnormal; 2. knowing the sex of the child before its birth emphasizes the abnormality of the pregnancy and therefore draws attention to the problem of the age of the mother; 3. this last chance of pregnancy emphasizes the question, which is near in time for these women, of the menopause, of getting old and of death; 4. it also emphasizes in a most emphatic way the question of mourning, of loss, of the place of the future child in the history of the woman and in a more general way the question of the desire to have a baby.

Adult↗
PubMed1976

[Preliminary psychological evaluation of a group of children before and after renal transplantation].

Eighteen children who have received kidney transplants within the last three years at the Hopital des Enfants Malades in Paris provide material for this survey. We try to find out how these transplants effect the way the children live, and the main psychological problems that they create. This new way of life is characterized by an explosion of vitality, a certain liberation from prior restraint and the possibility of activities which up to then had been difficult or forbidden. However, the necessity for the child to be watched regularly, to attend the hospital for examination, to follow a special diet, to take immunodepressive drugs remind him that he is not cured. Consequences of corticotherapy and the growth retardation remain essential problems for some of them. The child will have to cope with this complex situation which also creates difficulties to acquire independence.

Adolescent↗
PubMed1976

Renal transplantation in children: a psychological survey.

Psychological tests were carried out on 24 children with renal disease during the time they were hemodialyzed and after a minimum of one year after their transplant. These investigations included regular interviews with children and families, drawings and their commentaries, and projective techniques: Rohrschach tests. The results of these investigations indicated that the psychological status of the transplanted child could not be singled out and isolated from the effects of being ill, the different therapeutic procedures, and the personal history. Beyond the appearance adolescents give of a satisfactory social adjustment and beyond the explosion of vitality frequent amongst younger children, an impoverishment of their personality and major difficulties manifest themselves in coping with personal problems and identity crises especialy as far as agressiveness and sexuality are concerned. This neurotic mechanism appears mainly due to the traumatic experiences these children have experienced and their lack of support in mastering them through the verbalization process.

Activities of Daily Living↗
PubMed1973

Independence of H-2K and H-2D antigenic determinants on the surface of mouse lymphocytes.

At 37 degrees C, fluorescein-conjugated anti-H-2 alloantibodies specifically induce, at the surface of living mouse lymphocytes, the redistribution of the corresponding H-2 antigens, which cluster as patches and sometimes single caps at one pole of the cell. This aggregation is inhibited at 0 degrees C and the H-2 antigens, stained by fluorescent antibodies in the cold, appear evenly spread over the cell surface. This phenomenon was used to define the relationships between the membrane structures bearing the antigens coded by the H-2K and the H-2D genes of the H-2 region. Monospecific anti-H-2 antibodies coupled to either tetramethyl rhodamine isothiocyanate or fluorescein isothiocyanate were used to induce the redistribution of H-2D and H-2K antigens of the H-2(b) and H-2(k) haplotype at the surface of lymph node cells from homozygous and F(1) hybrid mice. It was observed that the diffuse distribution of H-2K antigens labeled at 0 degrees C was not affected by the prior antibody-induced aggregation of H-2D antigens and vice versa. The results were the same for H-2 antigens governed by genes located either in cis or in trans position. These data indicate that the H-2K and H-2D antigens migrate independently at the cell surface, and suggest that the gene products from the D and the K end of the H-2 region are expressed on independent molecules or structures at the cell membrane.

Animals↗