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Biomedical subjects

B E Wilson

Publications and source records attributed to B E Wilson.

At least 37 records · Page 2Linked to original sources

Stability of monoclonal antibody-defined epitopes.

Epitope instability can limit the applications of monoclonal antibody (mAb) technology in laboratory and clinical research. We exposed a group of representative antigens on human hepatocellular carcinoma (HCC) cells to physiochemical insults to study epitope stability as measured by mAb immunoreactivity. Each epitope was found to have a unique pattern of instability which serves to biophysically characterize the antigen and defines the conditions to which the antigen can be exposed during laboratory and clinical investigations. Individual antigens were found to be unstable within a surprisingly well defined window of solvent polarities while being stable on either side of that window. Several antigens were observed to be unstable when exposed to transient changes in pH. When a critical temperature between 42 degrees C and 65 degrees C was achieved, epitopes which were thermosensitive underwent a sudden loss in immunoreactivity. This critical temperature was found to be pH dependent. The effects of polarity, pH, and temperature on epitope stability are consistent with changes in protein structural conformation. In addition, we found that certain fixatives cause a time and concentration dependent loss of epitope immunoreactivity. This study provides a rapid and easy determination of monoclonal antibody-defined epitope stability; the results of which serve to guide further studies on the antigen and to characterize the antigen on the basis of its unique physiochemical stability.

Animals↗

Hormonal influence on language development in physically advanced children.

Sex differences in language performance have long been noted, with females more verbal and males superior in visual-spatial tasks. Two theories seek to explain the differences in language function. Waber (1976, Science, 193, 572-574) suggests that these sex differences are secondary to differences in bilateral language function related to the faster maturation rate in girls. Geschwind and Galaburda (1985, Archives of Neurology, 42,(I), 428-459; (II), 521-552; (III), 634-654) on the other hand posit an intimate interrelationship of sex hormones, the immune system, and laterality as influencing the ultimate asymmetry of the nervous system, which in turn could account for such differences. In the present study, language function was examined in patients with accelerated maturation caused by conditions with sex hormone elevation (idiopathic precocious puberty and congenital adrenal hyperplasia). The degree of maturational advancement was similar between the two groups. However, significant language performance differences were noted between androgen- vs. estrogen-exposed patients, regardless of genetic sex or diagnosis of the patient, indicating a hormonal effect on language development over time. These data support Geschwind and Galaburda's multifactorial theory for the origin of sex differences in language performance, and argue against Waber's maturational hypothesis.

Adrenal Hyperplasia, Congenital↗

Black English in a Mississippi prison population.

Nine linguistic features unique to Black English were examined in the speech of 87 Black and 77 White inmates of a Mississippi prison population. The purpose of the study was to determine whether Black inmates could be distinguished from White inmates by their use of the present progressive, final stops, distributive be, remote aspect been, noun plurals, third person singular present tense, possessives, consonant clusters, and the copula. Results showed that use of eight of the nine features accurately predicted the ethnicity of the subjects. Only remote aspect been failed to identify ethnic differences. Identification of dialect variation among minority populations and more specifically among prison populations is an important step toward providing effective remediation programs.

Adult↗

Identification of candidate genes for a factor regulating body weight in primates.

A weight gain of 20-30% above baseline, induced by gastrostomy overfeeding of subhuman primates or gavage overfeeding of rats, was found to completely suppress voluntary food consumption. When overfeeding was discontinued, body weight and oral intake returned in a coordinated fashion to baseline or "set point" values. This regulatory response could have been due to a circulating peptide that was secreted by adipocytes in proportion to the total body energy store and that mediated satiety at the level of the central nervous system. To search for this factor, a subtractive cDNA cloning strategy was developed, permitting the isolation of primate adipocyte genes with augmented expression in the overfed state. A 1.8-kb cDNA clone prepared by subtraction was found to hybridize to a 5-kb message expressed preferentially in the adipose tissue of overfed macaques and rats. This message, which was restricted in distribution among nonadipose tissues, was also detected in human subcutaneous fat. Candidate genes for satiety factors identified by this approach could be used in further studies of body weight regulation and obesity.

Adipose Tissue↗

Characterization of a malignant phenotype-associated cell surface glycoprotein common to various human tumor cells and preferentially expressed on adenocarcinoma of the lung.

Since both the liver and lung are derived from the endoderm, common antigens may appear on both tissues during malignant transformation. In an attempt to delineate cell surface alterations associated with the neoplastic transformation of these tissues, we have produced a library of monoclonal antibodies against a human hepatoma cell line termed FOCUS. One of these monoclonal antibodies, designated AF-10, recognized an antigen preferentially expressed on human lung adenocarcinoma cells, both in vitro and in vivo. This antigen has been characterized using Western immunoblot analysis and immunoprecipitation from surface-iodinated or metabolically labeled cells. The mature antigen is a cell surface glycoprotein with a core polypeptide with a molecular weight of 75,000 bearing N-glycosylation units. This protein migrates in sodium dodecyl sulfate-polyacrylamide gel electrophoresis with an apparent molecular weight of 100,000-115,000 in reducing conditions and Mr 115,000-130,000 in nonreducing conditions. The epitope recognized by monoclonal antibody AF-10 is borne by the core protein. This antigen is shed from the cell surface and was identified in the culture supernatant from lung adenocarcinoma cell lines. Studies of the biodistribution of the AF-10 antigen showed that it was also expressed at low levels in normal human small intestine and kidney. The AF-10 monoclonal antibody may be useful for the study of the antigen expression between normal lung and the transformed phenotype.

Adenocarcinoma↗

Aortic root dilatation associated with partial trisomy 7(q31.2----qter).

Aortic root dilatation and mitral valve prolapse are cardiac findings sometimes seen in disorders of connective tissue, most often in the Marfan syndrome. This report describes an infant with these cardiac anomalies and a specific chromosomal abnormality, partial trisomy of chromosome 7 associated with partial monosomy of chromosome 22. This association may have significance with respect to the etiology of cardiac disease in connective tissue disorders such as Marfan syndrome.

Aorta, Thoracic↗

Improved and large-scale synthesis of certain glycosyl cyanides. Synthesis of 2,5-anhydro-5-thio-D-allononitrile.

The first synthesis of 2,5-anhydro-5-thio-D-allononitrile starting with L-lyxose, via a trifluoromethanesulfonic ester intermediate, has been accomplished. Methods have been developed to achieve a large-scale synthesis of 3,4,5,7-tetra-O-acetyl-2,6-anhydro-D-glycero-D-talo-heptononitrile (5). An improved procedure has been developed to synthesize 2,5-anhydro-3,4,6-tri-O-benzoyl-D-gulononitrile (9). The structures of 5 and the thioamide derivative from 9, 2,5-anhydro-3,4,6-tri-O-benzoyl-D-gulonothioamide, were confirmed by X-ray crystallographic analysis.

Carbohydrate Conformation↗

Synthesis of glycopyranosylphosphonate analogues of certain natural nucleoside diphosphate sugars as potential inhibitors of glycosyltransferases.

The synthesis of alpha-D-glucopyranosyl-, alpha-D-galactopyranosyl-, and alpha-D-mannopyranosylphosphonate is described. Condensation of tris(trimethylsilyl) phosphite with 2,3,4,6-tetrakis-O-(phenylmethyl)-1-O-acetyl-alpha-D-glucopyranose generated 2,3,4,6-tetrakis-O-(phenylmethyl)-alpha-D-glucopyranosylphosphonic acetic anhydride (13). The benzyl blocking groups were removed by catalytic hydrogenation, and the anhydride bond was cleaved by alkaline hydrolysis to obtain alpha-D-glucopyranosylphosphonate (15). alpha-D-Galactopyranosylphosphonate (17) and alpha-D-mannopyranosylphosphonate (19) were also similarly synthesized. The anomeric configuration of 15 was assigned by single-crystal X-ray analysis, and the structural assignments of 17 and 19 were made on the basis of comparative NMR spectral studies. Compound 15 was then coupled with adenosine 5'-phosphoric di-n-butylphosphinothioic anhydride in dry pyridine to give adenosine 5'-phosphoric alpha-D-glucopyranosylphosphonic anhydride (23). Similarly, uridine 5'-phosphoric alpha-D-galactopyranosylphosphonic anhydride (24) and guanosine 5'-phosphoric alpha-D-mannopyranosylphosphonic anhydride (25) were synthesized from 17 and 19, respectively. With ovalbumin as an acceptor for [3H]galactose, provided by UDP-[3H]galactose, only uridine 5'-phosphoric alpha-D-galactopyranosylphosphonic anhydride (24) was shown to inhibit glycoprotein beta-D-galactosyltransferase (EC 2.4.1.38), with an apparent Ki equal to 165 microM. Even though these ionic compounds hardly penetrate the cell membrane, preliminary in vitro antitumor screening shows that compounds 23 and 25 are slightly active against human B-lymphoblastic leukemia and human T-lymphoblastic leukemia. None of these compounds show any antiviral activity.

Animals↗

Autografting and allografting of bovine ocular squamous cell carcinoma.

The autografting and allografting of bovine ocular squamous cell carcinoma was attempted. Autologous transplantation of primary ocular squamous cell carcinoma to subcutaneous sites initiated tumour growth at some sites in 11 of 17 animals when tumour pieces were used. The transplanted tumours showed progressive growth after a latent period of one to 10 weeks and attained a size of 1 cm between two and 16 weeks after implantation. Autologous tumour pieces also grew in the thoracic cavity of one animal but failed to grow in the peritoneal cavity of this animal and three other cattle. Tumour pieces obtained from subcutaneous autografts of two animals were reduced to single cell suspensions by trypsinisation at 37 degrees C and 4 degrees C. Each of these animals received five subcutaneous injections of 15 X 10(6) viable autologous cells per site for each preparation. No progressive growth was recorded at these sites. Autologous cultured tumour cells also failed to initiate progressive growth in two animals receiving 5 X 10(6) and 15 X 10(6) viable cells respectively. Pieces of subcutaneous autografts were reimplanted on five animals and progressive tumour growth was initiated on all five animals. In one animal the tumour pieces used for reimplantation had been stored in a liquid nitrogen refrigerator for seven days. Allografting was successful in only one of 10 attempts. The allograft grew until 10 weeks after implantation, then regressed spontaneously. No spontaneous regression was seen with autografts after progressive growth was recorded.

Animals↗

Immunotherapy of bovine ocular squamous cell carcinomas.

Squamous cell carcinomas were collected from the eyes of cattle and saline phenol extracts of the tumours were prepared. The aqueous phase of the extract was used in studies on the immunotherapy of ocular squamous cell carcinomas in cattle. After a single intramuscular injection of the extract, regression and sometimes complete disappearance of eye tumours were observed in 39 of 46 carcinomas. Tumours as large as 4 X 5 cm regressed completely. Enhanced growth of tumours was noted in two of three cattle given multiple injections. Regressing tumours were examined histologically and regression appeared to be associated with a cell-mediated immune reaction. Spontaneous regression of a confirmed squamous cell carcinoma was observed in one animal. This spontaneous tumour in one of the larger domestic animals provides a useful experimental model for the study of tumour antigens.

Animals↗

Cytotoxic antibody in the serum of cattle with squamous cell carcinoma.

Sera from two cattle with ocular squamous cell carcinomas were cytotoxic for two different cultures of cells derived from bovine ocular squamous cell carcinomas. Sera from normal cattle, and from one tumour-bearing animal, were not cytotoxic. Cytotoxicity could be demonstrated in vitro only in the presence of guinea-pig complement.

Animals↗