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Biomedical subjects

A Benammar

Publications and source records attributed to A Benammar.

13 recordsLinked to original sources
PubMed1995

Does pathologic node status affect local control in patients with carcinoma of the head and neck treated with radical surgery and postoperative radiotherapy?

PURPOSE: To evaluate the effect of pathologic lymph node status and nodal stage on local control at the primary site in patients with advanced squamous cell carcinomas of the head and neck, treated with radical surgery and postoperative irradiation. METHODS AND MATERIALS: Fifty-seven patients with advanced squamous cell carcinomas of the oral cavity, oropharynx, hypopharynx, larynx, and supraglottic larynx were analyzed. All patients underwent resection of the primary lesion, neck dissection, and postoperative radiotherapy. Minimum follow-up was 2 years. The median dose to the primary tumor bed was 60.4 Gray (range 39.7-72.0). Besides pathologic nodal status (pN0 vs. pN+) and nodal stage, the following factors were analyzed for their impact on local control: age, gender, T stage, tumor grade, resection margins, interval from surgery to irradiation, dose to the primary site, and overall treatment time. RESULTS: The 3-year actuarial local control rate was 78%. When all patients were analyzed, nodal status (pN0 vs. pN+) did not affect control at the primary site (71% vs. 82%, p = 0.42). Nodal stage (pN0-N2a va. pN2b-N2c) was also not a significant factor for local control (74% vs. 82%, p = 0.57). When only patients with negative margins were analyzed, nodal status again did not impact on local control (79% vs. 90% for pN0 vs. pN+, p = 0.39). On univariate analysis, only tumor grade, margin status, and elapsed days were significant factors for local control. Local control was 85% for patients with negative margins vs. 60% for those with positive margins (p = 0.016). For patients with moderately and poorly differentiated tumors, local control was 86% as compared to 50% for patients with well-differentiated tumors (p = 0.007). When radiotherapy was completed within 50 days, local control was 93% as opposed to 63% for > 50 days (p = 0.016). On multivariate analysis, only margin status (p = 0.002) and tumor grade (p = 0.007) remained significant. CONCLUSION: We conclude that neither the presence of pathologically positive nodes nor nodal stage is a prognostically significant factor for local control in patients who have undergone radical surgery and postoperative radiotherapy for advanced squamous cell carcinomas of the head and neck. We do not recommend a change in treatment philosophy, such as an increase in dose to the primary site, based on the pathologic status of the neck.

Carcinoma, Squamous Cell↗
PubMed1994

The role of radiotherapy in the treatment of breast cancer: results of perioperative implantation.

Between 1982 and 1993, 620 of 938 patients with pathologically staged I-II breast cancer were treated at the time of reexcision (perioperatively), with an iridium-192 (Ir-192) implant to the tumor bed to give 2000 cGy to the 30 to 40 cGy/ph isodose line. This was followed by 4500 cGy to the entire breast at 180 cGy/d for 25 fractions. The local control for the 620 patients at 5 and 10 years was 93 and 89%, respectively. The actuarial survival at 5 and 10 years was 92 and 81%. The cosmetic results were good to excellent for 87% of the patients. Chemotherapy had no impact on local control in this study. Ir-192 implant is especially useful for deep tumors, making possible more flexibility in the techniques used to boost the tumor volume. Perioperative implantation has increased the accuracy of placing the boost dose, shortened the overall treatment time, and, for some patients, eliminated the need for rehospitalization and anesthesia.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1983

Structural studies of a wild rabbit immunoglobulin light chain constant region.

The amino acid sequence of a wild rabbit light chain constant region of allotype b95 was nearly completely determined by manual and automated Edman degradation procedures. The comparison of the b95 primary structure with the other b allotypes reveals about 20% substitutions between b95 and b4, b5 and b6, and 36% between b95 and b9. The substitutions are clustered in parts of the chain in agreement with our sequence data for b5 and b6. The presence in b95 of the characteristic cysteine residue at position 170 and the tryptophane residue at position 147 is in agreement with the serological similarity of these various rabbit kappa light chains. The examination of the rate of amino acid substitutions between the b95 chains and the other b allotypes shows that b95 is closer to b4, b5 and b6 than to b9.

Amino Acid Sequence↗
PubMed1983

Mouse monoclonal antibodies against rabbit b6 allotype and their use for characterization of light-chain subpopulations.

Mouse anti-allotypic hybridomas directed against different antigenic determinants of the b6 rabbit allotype have been raised. The fine specificity of these monoclonal antibodies (mAbs) was determined by radioimmunoassay and it was possible to classify them into three groups, each directed against distinct epitopes of the b6 allotype. Hare "b6" IgG were tested with anti-b6 mAb and no reaction was found indicating that the number of allotopes present on b6 molecules is greater than the three detected by the mAb. Comparative analysis by precipitation in gel of IgG from homozygous b6/b6 rabbits using mouse mAb and rabbit anti-b6 antibodies suggested that at least two categories of molecules can be discriminated. The observation of b6 subpopulations was confirmed by isolation of a minor subpopulation of IgG on a mouse monoclonal immunoadsorbent.

Animals↗
PubMed1982

A second rabbit kappa isotype.

Immunoglobulin G (IgG) from the rabbit strain Basilea was previously shown to contain two distinct populations of molecules one with light chain belonging to the known lambda isotype and the others to a new kappa-like L chain type. Alloantisera prepared against the Basilea IgG are directed against the kappa-like light chain (anti-bas antisera). All Basilea rabbits express kappa-like chains recognized by anti-bas sera, but IgG from other domestic rabbits did not react with these antisera. Genetic studies of wild rabbits belonging to different populations show that the bas+ phenotype could be found in heterozygous rabbits as well as those homozygous at the b locus. The gene encoding the bas+ light chain is closely linked to the b locus. Moreover, antigenic determinants recognized by anti-bas antibodies and antigenic determinants recognized by antibodies directed against allotypic determinants of the b series are located on distinct IgG molecules. These results show that there are two rabbit kappa isotypes: the kappa 1 isotype, bearing allotypic determinants of the b series, and the kappa 2 isotype, for which bas+ chain is one of the allotypic forms. The kappa 1 and kappa 2 isotypes are controlled by closely linked genes.

Animals↗
PubMed1982

BASILEA rabbits express two types of immunoglobulin light chains: lambda and kappa-like.

In the variant rabbit strain BASILEA, immunoglobulin G were shown to contain two distinct populations of IgG molecules whose light (L) chains belonged to the known lambda isotype and to a new kappa-like type. These two L chains differed from each other by electrophoretic, chemical, and antigenic properties. The kappa-like L chain fraction showed (i) an acid-labile Asp-Pro bond at the end of the joining region and (ii) a tryptic peptide, whose amino acid sequence of the NH2-terminal 15 residues was identical to the homologous constant (C) region sequence of b9 kappa chain with the exception of the residue in position 70, which is asparagine in the kappa-like chain instead of the characteristic half-cystine residue in all L chains of kappa B type expressing b4, b5, b6, or b9 allotypes. The data suggest that the kappa-like L chain component does not contain the C region half-cystine residue involved in the formation of the extra variable (V) region-C region disulfide bridge in L chains of the kappa B [Rejnek, J., Appella, E., Mage, R. G. & Reisfeld, R. A. (1969) Biochemistry 8, 2712-2718]. The partial NH2-terminal amino acid sequence of the C region of the kappa-like L chain was shown to be markedly different from b4, b6, or b9 region sequences and from rabbit lambda C region sequence. Taken together, the chemical data suggest that the kappa bas component represents a new subtype of kappa chain. A rabbit alloantiserum made against bas IgG and adsorbed with IgG fractions showing b4, b5, b6, b95, and b96 L chain allotypes appeared to be directed against the kappa-like L chain component of BASILEA IgG exclusively. All BASILEA animals expressed IgG molecules containing kappa-like chains; in contrast, IgG molecules derived from the standard domestic rabbit did not react with this antiserum.

Amino Acid Sequence↗
PubMed1981

B 96, a seventh allele at the rabbit kappa chain b locus.

A previously undetected allotypic specificity, A96, was observed in the wild rabbit population of Zembra (Tunisia). The A96 allotype is inherited as a b allotype, and its antigenic determinants are located on the kappa light chains of immunoglobulins. Although cross-reacting with b6, the A96 allotype carries its own allotypic determinants, and is therefore distinct form the known allotypes of the b series (b4, b5, b6, b9, b4var and b95). The data indicate that A96 is encoded by an allele at the b locus, tentatively designated b 96.

Alleles↗
PubMed1981

An 8th rabbit b allotype (b92) detected by a genetic study.

Genetic study of the progeny of a Spanish wild rabbit has revealed 2 unknown allotypic specificities that behave as encoded by alleles at the b locus. One of these A92 is described in this paper. This specificity is located on immunoglobulin light chains and cross-reacts with anti-b4 and presumably with anti-b9 sera. These data indicate that A92 is a "new" allotype of the b series and is thus designated b92.

Animals↗
PubMedDate not supplied

Rabbit immunoglobulin allotypes: cross-reactivities of the b95 and b96 allotypic specificities with the allotypes of the b series present in domestic rabbits.

In a population of wild rabbits originating from the Island of Zembra (Tunisia), several unknown allotypic specificities of the b series have been detected and two of them, b95 and b96, have already been described. In order to learn about their relationship with other allotypes of the same series and present in the domestic rabbit, a study of b95 and b96 cross-reactions with heterologous antisera was undertaken. From the data presented in this paper, it can be concluded that the b96 allotype is very closely related to the b6 allotype, which suggests that they are encoded by real structural genes at the b locus as presumed for b4 and b4var allotypes; the b95 allotype, which behaves as an intermediate form, can be considered as an ancestral allotype.

Animals↗
PubMedDate not supplied

Characterization of the b99 allotype of rabbit immunoglobulin kappa 1 light chain.

A previously undetected allotypic specificity, A99, was found in a wild rabbit (Oryctolagus cuniculus) population in Portugal. The A99 allotype cross-reacted with anti-b6 and anti-b96 sera, but carried its own antigenic determinants and was therefore distinct from the known allotypes of the b series. The A99 determinants were located on the kappa 1 light chain of IgG molecules and were inherited as allotypic determinants of the b series. Taken together, these data provide evidence that A99 is encoded by an allele at the b locus, tentatively designated b99. The great similarity between the b6, b96 and b99 allotypes suggests that they derived from a common ancestor.

Animals↗
PubMedDate not supplied

A and b allotypy in Oryctolagus and Lepus species.

It had been previously shown by the description in wild rabbits Oryctolagus cuniculus of unknown allotypic specificities belonging to the a series and the b series, that the genetic polymorphism found in domestic rabbits was only a part of the genetic polymorphism of the species O. cuniculus. To the known a1, a2 and a3 allotypic specificities have been added in the last years a100 and a101 which are under the control of allelic genes at the a locus. Studies of cross-reactivities in the a system is a way to detect variants of a given allotypic specificity. The phylogenetic studies in the hare Lepus capensis demonstrate that a2 and a3 determinants are allotypic, apparently without polymorphism in this species; indeed, all the tested hares have either a2 or a3 determinants or both. Four presumably "new" allotypic specificities of the b series, A93, A94, A95 and A96 have been found in a population of wild rabbits O. cuniculus from an Island in Tunisia. A95 allotypic specificities against which specific antisera have been prepared, shows cross-reactivities with b4, b5 and b6 allotypes of domestic rabbit. Genetic data demonstrate that A95 is indeed under the control of an allele at the b locus. If schematic mechanisms involving duplication and mutations of genes are suitable to understand the presence of variants and their cross-reactivities, one has to understand how so many genes are involved in allotypy and how it remains stable during evolution.

Animals↗