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Biomedical subjects

A Chtourou

Publications and source records attributed to A Chtourou.

5 recordsLinked to original sources

[Endobronchial pulmonary rhabdomyosarcoma. A case report].

We report a case of pleiomorphous pulmonary rhabdomyosarcoma observed in a 64-year-old patient with no history of soft tissue tumor. The tumor was found extending into the right lower and middle lobes. The intra-parenchymatous extension protruded into the middle lobular bronchus and was prolonged by a 4 cm polyp. The polyp extended up to the carina and reached the contralateral common bronchus. Outcome was fatal after surgery performed in an emergency setting due to asphyxia. Explorations could not be continued to determine the primary or secondary nature of the tumor. An intraparenchymatous endobronchial localization is uncommon. Primary rhabdomyosarcoma is generally a purely intra-parenchymatous tumor. The endobronchial localization has been described before but is very exceptional. This localization would also be exceptional for secondary rhabdomyosarcoma mimicking a primary malignant tumor. The histology study revealed an undifferentiated pleiomorphous tumor. Immunohistochemistry provided the final diagnosis.

Bronchial Neoplasms↗

Preparation and amino acid sequence of human kappa-casein.

Human kappa-casein was prepared from whole casein by successive hydroxyapatite and thiol-Sepharose chromatographies. The primary structure of its 99-residue N-terminal fragment has been determined by sequencing peptides obtained by tryptic and chymotryptic digestions of the whole protein. This fragment overlaps the known sequence of the 65-residue C-terminal fragment. The 158-residue sequence of human kappa-casein was compared to those of goat, ewe, cow and rat kappa-caseins. Only 22% of the residues are identical in homologous positions. The rate of divergence of the 93-residue N-terminal segment (para-kappa-casein) appears to be higher than that of the rest of the molecule.

Amino Acid Sequence↗

Quantification of beta-casein in human milk.

A method is described for preparing immunologically homogeneous human milk beta-casein, against which monospecific rabbit antiserum was prepared. The antiserum was used to quantify beta-casein, the major human casein, by rocket immunoelectrophoresis in individual milk samples. However, it was found that in most samples beta-casein occurred together with degradation products originating from its proteolysis by plasmin. Immunological quantification of human beta-casein, treated with plasmin for various time periods, showed that rocket height was not affected by proteolysis up to degradation states clearly more advanced than those observed in all samples of fresh human milk tested. Assays of 150 individual milk samples from 80 women, covering a lactation period of up to 730 d, gave an average concentration of beta-casein (native + degraded) of 4.67 +/- 0.89 standard deviation (g/l); extremes at 2.1 and 7.3 g/l did not vary significantly during the period under study. Comparison of this average value with an accepted casein content of 4.4 g/l (Macy & Kelly, 1961) showed that the casein content of human milk is underestimated when obtained by N determinations on milk and on its supernatants at pH 4.6 (whey). Caseins other than beta-casein occurred only in minute amounts, if at all.

Amino Acids↗

Does beta-lactoglobulin occur in human milk?

Although beta-lactoglobulin (beta-lg) has been considered to be absent from human milk, recent results of other workers, based on immunological reactions between human milk and rabbit antiserum to bovine beta-lg, suggest that this protein may be present. Although our results show similar immunological reactions, we consider that lactoferrin is responsible for these, as it was the only reactive protein species which could be prepared to homogeneity. Indeed two types of antibodies were found by ELISA test in the antisera to bovine beta-lg. One of them would be able to bind loosely to human lactoferrin, but its binding sites would not be antigenic in the rabbit.

Animals↗