Alan Frederick Williams 25 May 1945 - 9 April 1992.

Alan WIlliams is noted for his seminal contributions to the field of leucocyte membrane glycoproteins (that is, differentiation antigens). He played a leading role in the development of approaches to the purification and structural analysis of cell surface antigens. His comprehensive characterization of the structure of the rat Thy-1 antigen, as well as the application of monoclonal antibodies to the designation and subsequent isolation of multiple new leucocyte antigens, were exemplary. His discovery that Thy-1 is structurally related to immunoglobulin led directly to the concept of the immunoglobulin (Ig) superfamily, which embraced a spectrum of cell surface molecules involved in a variety of cell recognition systems. He was a very strong advocate in support of the rat as a model animal in the study of immunological phenomena. He was energetic and courageous, as well as radiating enthusiasm for immunological research, inspiring others, critically analysing accepted dogmas and setting high standards. In short, he was a brilliant research scientist.

Estudio de la clinica, patologia, estadios, evolucion del melenoma y marcadores pronosticos (PCNA y EGFR) / Study of the clinic, pathology, stadiamevolution from melanoma and prognosis makers

Se estudiaron 29 melanomas,en forma prospectiva en relacion a la exprecion del antigeno de proliferacion nuclear(PCNA)indicador de proliferacion celular y del receptor del factor de crecimiento epidermico(EGFR) responsable de estimular la hiperplasia.La PCNA mostro valores elevados y se correlaciono con los parametros habituales.El EGFR con bajo nivel de expresion,presento en el seguimiento un llamativo incremento en los niveles de invasion mas agresivos(nivel V)y en los casos del grupo de"fallecidos".

Estudio de la clinica, patologia, estadios, evolucion del melenoma y marcadores pronosticos (PCNA y EGFR) / Study of the clinic, pathology, stadiamevolution from melanoma and prognosis makers

Se estudiaron 29 melanomas,en forma prospectiva en relacion a la exprecion del antigeno de proliferacion nuclear(PCNA)indicador de proliferacion celular y del receptor del factor de crecimiento epidermico(EGFR) responsable de estimular la hiperplasia.La PCNA mostro valores elevados y se correlaciono con los parametros habituales.El EGFR con bajo nivel de expresion,presento en el seguimiento un llamativo incremento en los niveles de invasion mas agresivos(nivel V)y en los casos del grupo de"fallecidos".AU

Granulocyte-macrophage colony-stimulating factor induces the expression of the CD11b surface adhesion molecule on human granulocytes in vivo.

The CD11b (Mol) molecule is a member of a family of surface glycoproteins that are essential for adhesion-dependent granulocyte functions. Brief exposure of granulocytes to human granulocyte-macrophage colony-stimulating factor (GM-CSF) in vitro increases the surface expression of CD11b and increases granulocyte adhesiveness. To assess the possible in vivo significance of these observations we studied the effect of GM-CSF on CD11b, CD11a (LFA-1), and CD11c (gp 150, 95) expression on granulocytes from nine adult patients with sarcoma who were receiving GM-CSF as part of a phase I trial. GM-CSF was administered as a continuous infusion at a dose of 32 or 64 micrograms/kg/d. Granulocyte CD11b, CD11a, and CD11c expression was determined by indirect immunofluorescence staining of whole blood, thereby minimizing in vitro manipulation. A transient leukopenia developed within 15 minutes of initiation of GM-CSF treatment that was associated with a marked increase in the surface antigen density of CD11b. A mean 1.7-fold increase (P = .001) in the percentage of CD11b-positive granulocytes and a mean 2.1-fold increase (P = .002) in CD11b surface antigen density was noted after 12 hours of treatment. No change in CD11a or CD11c expression was observed over the first 12 hours. The level of CD11b expression was followed in six patients for up to 5 days of treatment with GM-CSF. Compared with the 12-hour value, three of six patients showed a subsequent decrease in CD11b expression, two remained constant, and one showed a continued increase in CD11b surface density. Fluorescence-activated cell sorting of granulocytes into high- and low-density CD11b-positive groups revealed a preponderance of immature myeloid forms in the low-density CD11b fraction, which suggests that the late decrease in CD11b expression in some patients may be related to a greater proportion of circulating immature myeloid forms in the peripheral blood. This study suggests that GM-CSF administered as a continuous infusion rapidly upregulates the expression of granulocyte CD11b in vivo. The influence of this phenomenon on in vivo granulocyte aggregation may be clinically relevant with regard to the toxicity of GM-CSF and deserves further investigation.