The North American experience with photopheresis

Photopheresis or extracorporeal photochemotherapy (ECP) is a novel immunomodulatory therapy based upon pheresis of light-sensitive cells. Whole blood is removed from patients who have previously ingested the photosensitizing agent 8-methoxypsoralen (8-MOP) followed by leukapheresis and exposure of the 8-MOP containing white blood cells (WBCs) extracorporeally to an ultraviolet A (UVA) light source prior to their return to the patient. In 1988, the Food and Drug Administration (FDA) approved photopheresis for the treatment of cutaneous T-cell lymphoma (CTCL). Treatment of CTCL with photopheresis has been reported in over 300 patients worldwide. Photopheresis has also demonstrated encouraging results in the treatment of solid organ transplant rejection, graft versus host disease, scleroderma, and other autoimmune diseases although fewer patients have been studied. This review will focus on the North American experience with photopheresis.

Biotinylation modifies red cell antigens

BACKGROUND

Chemical biotinylation of red cell membranes may be useful for several clinical applications, including red cell survival studies.

STUDY DESIGN AND METHODS

To examine the possible effects of biotinylation on red cell antigens, standard hemagglutination assays were performed on matched sets of control and biotinylated red cells. The red cells were biotinylated at a final concentration of 2.0 pg of sulfo-N-hydroxysuccinimide-biotin per cell, and antigen-negative cells were directly compared to antigen-positive cells when possible. The hemagglutination assays were graded in a blinded fashion. Forty-one red cell antigens from 21 of the 23 established blood group systems were tested.

RESULTS

Hemagglutination based upon antibody binding to A, A1, M, N, S, s, P1, D, C, E, c, e, C(w), Lu(b), K, k, Kp(b), Le(a), Le(b), Fy(a), Fy(b), Jk(a), Jk(b), Di(a), Wr(a), Wr(b), Yt(a), Xg(a), Sc1, Do(b), Co(a), Ch, H, Ge2, Cr(a), Kn(a), I, and P was not affected by biotinylation. Unexpectedly, the hemagglutination of Di(b+) and LW(a+) red cells was blocked after biotinylation. Conversely, MH04 monoclonal anti-A agglutinated red cells expressing B only after biotinylation. BIRMA-1 monoclonal anti-A and polyclonal anti-A from sera did not agglutinate the biotinylated B red cells.

CONCLUSION

Biotinylation of human red cells specifically modified their antigenicity, as measured by standard hemagglutination assays.

Cationic photoimmunoconjugates between monoclonal antibodies and hematoporphyrin: selective photodestruction of ovarian cancer cells

The photosensitizer hematoporphyrin (HP) was site specifically attached to a murine monoclonal antibody (MAb) fragment OC125F(ab?)(2) directed against ovarian cancer cells and to nonspecific rabbit immunoglobulin G. The photoimmunoconjugates were positively charged and were purified by column chromatography. The OC125F(ab?)(2) conjugate retained immunoreactivity with human ovarian cancer cells, and the binding was competed with unmodified MAb. Phototoxicity paralleled the cellular uptake with the OC125F(ab?)(2) conjugate and the light showing selective killing of target cells compared with nontarget cells. Nontargeted conjugates and free HP produced lower levels of phototoxicity and showed no selectivity.

Variegated transfer of recombinant glycosylphosphatidylinositol-anchored CD4 among cultured cells: correlation of flow cytometric and microscopic observations

Glycosylphosphatidylinositol-anchored proteins (GPI-proteins) expressed on the outer leaflet of cell membranes are involved in diverse physiologic as well as pathologic processes in humans. Previously, we demonstrated the intercellular transfer of overexpressed CD4-GPI in vitro from transduced HeLa cells to their parental cell line. In this report we present further information on the transfer process and the nature of the transferred GPI-proteins. In mixed-cell populations, the transfer of CD4-GPI was detectable within minutes at levels proportional to the ratio of donor and recipient cells. The amount of CD4-GPI detected with flow cytometry on the surface of the recipient cells varied according to cell type. Microscopy of mixed cell populations revealed discrete CD4-GPI containing aggregates on the target cells, whereas colocalized transfer of cytoplasm was not detected. Separation of cocultivated cells by semipermeable membranes largely prevented CD4-GPI transfer, but aggregates containing CD4-GPI were demonstrated by electron microscopy in supernatants passed through filters of 0.4-mm pore size.

Demographic and health status indicators to guide health promotion for Hispanic and Anglo rural elderly

Naturally occurring differences rather than simple breakdowns by ethnic category are being used to tailor strategies in a three year senior community health worker-delivered health promotion intervention. A survey conducted of persons 60 and over in a rural southwestern U.S. community identified New Anglos (recent settlers, n = 264), Old Anglos (long-time residents, n = 298) and Hispanics (n = 236) for a total of 798 persons. Significant demographic differences included less education, poorer health status and more chronic conditions among Hispanics. Low rates of screening were the norm but especially severe among Old Anglos. Patterned differences in health practices, as well as group variations in use of resources and sources of information, revealed New Anglos used a larger variety of services and media. Generally, adjustments being made are related to Hispanic culture, cosmopolitan orientation of the New Anglos, and long-term isolation from information and services for Old Anglos.

Observation of an A-DNA to B-DNA transition in a nonhelical nucleic acid hairpin molecule using molecular dynamics

One of the truly challenging problems for molecular dynamics (MD) simulations is demonstrating that the trajectories can sample not only in the vicinity of an experimentally determined structure, but also that the trajectories can find the correct experimental structure starting from some other structure. Frequently these transitions to the correct structure require that the simulations overcome energetic barriers to conformational change. Here we present unrestrained molecular dynamics simulations of the DNA analogs of the RNA 5'-GGACUUCGGUCC-3' hairpin tetraloop. In one simulation we have used deoxyuracil residues, and in the other we have used the native DNA deoxythymine residues. We demonstrate that, on a nanosecond time scale, MD is able to simulate the transitions of both of the A-DNA stems to B-DNA stems within the constraints imposed by the four-base loop that caps the helix. These results suggest that we are now in a position to use MD to address the nature of sequence-dependent structural effects in nonduplex DNA structures.

Testosterone concentrations and oligomenorrhea in women with acne

BACKGROUND

Androgen excess is frequently associated with oligomenorrhea as well as acne. Oligomenorrhea in hirsute women has been demonstrated to be associated with higher active testosterone levels than found in eumenorrheic hirsute women. This study was designed to evaluate whether similar findings are present in women with acne. Forty-four consecutive women with acne were evaluated by measuring their levels of total testosterone, biologically active testosterone, and free testosterone. The women with oligomenorrhea and acne had significantly higher levels of biologically active testosterone than those with eumenorrhea and acne. This implies that biological active testosterone should be measured in oligomenorrheic women with acne and, if elevated, consideration should be given to antiandrogen therapy.

METHODS

Data were collected from 44 consecutive Caucasian women aged 14 to 38 years. The patients were separated into two groups based on menstrual history. Group 1 had regular menses, and group 2 had oligomenorrhea, defined as menstrual intervals of greater than 36 days. All patients had blood samples drawn on their initial office visit, regardless of the phase of the menstrual cycle, and the levels of total testosterone (TT), biologically active testosterone (BT), and free testosterone (FT) were obtained.

RESULTS

The serum TT level was 87 +/- 41.3 ng/dL (range, 31-150 ng/dL) in oligomenorrheic women and 56 +/- 27.5 ng/dL (range 8-107 ng/dL) in eumenorrheic women. There was no statistically significant difference. The serum BT level in oligomenorrheic women was 33 +/- 16.9 ng/dL (range, 11-51 ng/dL) and in eumenorrheic women 19 +/- 13.6 ng/dL (range, 11-51 ng/dL). This difference was statistically significant (p < 0.05). The serum FT level in oligomenorrheic women was 18 +/- 9.4 pg/mL (range, 1-29 pg/mL) and in eumenorrheic women 10 +/- 7.1 pg/mL (range, 1-32 pg/mL). This difference was not statistically significant (Table 1).

CONCLUSIONS

Women with acne and oligomenorrhea, similar to women with hirsutism and oligomenorrhea, have higher levels of biologically active testosterone than those with normal menses.

Monoclonal antibodies against synthetic peptides corresponding to the extracellular domain of the human Ca2+ receptor: characterization and use in studying concanavalin A inhibition

We generated monoclonal antibodies against two synthetic peptides corresponding to residues 214-235 (ADD) and 374-391 (LRG) of the human Ca2+ receptor (hCaR) extracellular domain (ECD). Although both antibodies reacted well with their respective immunizing peptides on peptide-based enzyme linked immunosorbent assay, ADD was much more strongly reactive with the hCaR than LRG in assays such as immunoblots done under denaturing conditions. The opposite pattern was seen in flow cytometry analysis of the native receptor stably expressed in transfected 293 cells. We speculate that the ADD epitope is unexposed in the native receptor while the reverse is true for the LRG epitope. The ability to measure cell surface expression of the hCaR under native conditions using flow cytometry with the LRG monoclonal allowed us to study the basis for Concanavalin A (Con A) inhibition of CaR activation by Ca2+. Our studies show that Con A inhibition is partially accounted for by receptor internalization but, additionally, Con A may prevent Ca2+ stimulation directly by binding to carbohydrate residues in the receptor ECD.

Long-term, stable expression of green fluorescent protein in mammalian cells

Despite the proven utility of green fluorescent protein (GFP) as a reporter molecule for transient gene expression, the adequacy of this marker for models requiring durable, high-level gene expression has not been fully tested. To address this issue, we performed the transfection of Chinese Hamster Ovary (CHO) cells with plasmid DNA encoding both GFP and neomycin phosphotransferase (neo) cassettes. The expression of GFP was measured after the cells were cultured in the presence or absence of G418-mediated selective pressure. After removal of G418 from the growth medium, the percentage of pooled G418 resistant transfectants which co-expressed the GFP transgene increased or remained unchanged. Flow cytometric and visual isolation of GFP-expressing cells was possible without continued selection in G418. One cloned cell line, C463, maintained high-level green fluorescence for 18 weeks in G418 and an additional 12 weeks in nonselective medium. Our data suggest expression of GFP does not confer a growth disadvantage in mammalian cells.