ACCESSORY CELL ABILITY OF LANGERHANS CELLS FOR SUPERANTIGEN IS RESISTANT TO ULTRAVIOLET-B LIGHT

Abstract We examined the effects of ultraviolet-B (UVB) irradiation on the accessory cell ability of Langerhans cells (LC) to induce a T-cell response to a superantigen, staphylococcal enterotoxin B (SEB). The ability of LC-enriched epidermal cells (LC-EC) to evoke a T-cell response to SEB was retained at the doses of UVB (up to 40 mJ/ cm²) that profoundly affected the antigen-presenting function of LC-EC for a hapten, trinitrophenyl (TNP), and a protein antigen, conalbumin. Thus, the LC accessory function for superantigens is more resistant to UVB irradiation than that for ordinary antigens. This UVB resistance is presumably due to no requirement of antigen processing for superantigens as chemically fixed or chloroquine-treated LC-EC still retained their ability to induce T-cell responses to SEB. Higher doses of UVB (more than 60 mJ/cm²) reduced the accessory cell ability of LC-EC for SEB up to 50% of control. The addition of monoclonal antibodies against adhesion molecules between LC and T cells to the culture resulted in substantial suppression of the T-cell response to SEB induced by nonirradiated LC-EC, while the U VB-irradiated LC-EC-induced T-cell response was not significantly blocked with these monoclonal antibodies. This suggested that the reduction of LC ability for superantigen by high doses of UVB is at least partly due to impairment of adhesion molecules on LC by UVB irradiation.     

EPIDERMAL CELL-CONTRA-INTERLEUKIN 1 INHIBITS HUMAN ACCESSORY CELL FUNCTION BY SPECIFICALLY BLOCKING INTERLEUKIN 1 ACTIVITY

Ultraviolet B (UVB) radiation (280-320 nm) is capable of suppressing selected cell mediated immune responses by inhibiting the function of antigen presenting/accessory cells. Human keratinocytes and carcinoma cell lines (A431) upon UVB radiation or treatment with PMA secrete a suppressor factor, which blocks IL 1 activity (hEC-contra-IL 1). Therefore, the capacity of this UVB-inducible cytokine to modulate human accessory cell function was tested. Human peripheral blood mononuclear cells were stimulated with the mitogenic anti-CD3 monoclonal antibody OKT3 and thymidine incorporation into proliferating T-cells was measured as an index for monocyte accessory cell activity. Addition of hEC-contra-IL 1 which was purified by HPLC chromatography partially decreased OKT3 induced T-cell proliferation in a dose dependent manner. Human EC-contra-IL 1, however, failed to inhibit blastogenesis when T-cells depleted of accessory cells were stimulated in an accessory cell independent fashion via OKT3 attached to the bottom of microtiter plates. Recombinant human (rh) IL 1, but not rhIL 6 was able to reconstitute hEC-contra-IL 1 suppressed blastogenesis in a dose dependent manner. Furthermore, the combined addition of h-EC-contra-IL 1 and an antibody against rhIL 6 to cultures resulted in an additive inhibitory effect which could not be observed when hEC-contra-IL 1 was added together with a monoclonal antibody against rhIL 1 alpha/beta. These studies indicate that hEC-contra-IL 1 is capable of suppressing human accessory cell function by specifically blocking IL 1 activity. This property of hEC-contra-IL 1 points to a novel mechanism by which UVB radiation may modulate human accessory cell function in an indirect manner.     

ULTRAVIOLET RADIATION INHIBITS BOTH ACCESSORY CELL AND RESPONDER T CELL FUNCTION IN THE PROLIFERATIVE RESPONSE TO HAPTENATED-SELF

Abstract— Photoprotection i. e. the increased resistance of the cells preilluminated with near ultraviolet light (300–380 nm) to the lethal action of 254 nm radiations is observed in wild-type Escherichia coli B cells (which exhibits the Fil phenotype) but requires either an integrated prophage or a rec A mutation to be detected in E. coli K12 strains. Here we have demonstrated that significant photoprotection occurs in an E. coli K12 rec A⁺ cell containing the Ion allele which is responsible for filamentous growth (Fil phenotype) after 254 nm irradiation. The Fil phenotype can be suppressed by the sfi A of sfi B suppressor genes. Since the E. coli K12 rec A⁺ Ion sfi B strain exhibits no more photoprotection, these data support the conclusion that in Ion strains photoprotection is due to the abolition of the 254 nm induced filamentation by the near ultraviolet treatment. In addition, we show here that near ultraviolet illumination of the cells leads to a severe restriction of the bulk protein synthesis, as well as of the inducibility of β-galactosidase and tryptophanase. These effects are observed only in nuv ⁺ cells that contains 4-thiouridine the chromophore responsible for photoprotection. We propose that in Ion (lysogenic) strains, photoprotection is due to prevention of the SOS response. During the growth lag, the low residual level of protein synthesis does not allow the induction of the SOS response and accordingly prevents filamentation (the lytic cycle). Concomitantly the SOS triggering signals are eliminated via DNA repair.     

BILIRUBIN PHOTOTOXICITY TO HUMAN CELLS BY GREEN LIGHT PHOTOTHERAPY in vitro

Phototherapy of newborn infants with blue or green light is the most common treatment of neonatal hyperbilirubinemia. Using bilirubin bound to human lymphoid and basal skin cells we obtained the green light dose dependency of the bilirubin phototoxicity to these cell types. Cells (3–5× 10⁶/mL) were incubated with bilirubin complexed to human serum albumin (final concentrations 340 μM bilirubin, 150 μM albumin). Under these conditions all cells showed maximum binding of bilirubin. Irradiation with broadband green light (Λ_max= 512 nm) over 24 h led to a light dose-dependent population of cells, which contained no bilirubin on the cell membrane as determined by Nomarski interference microscopy. The light-induced mechanism of the disappearance of bilirubin caused lethal membrane damage to the cells (trypan blue exclusion test). The cell kill rate increased with the irradiation dose and with the fraction of cells with no bilirubin. When 90% of lymphoid cells were bilirubin free, 46% of them were dead (using 480 J cm^?1 green light). Similar results were obtained with basal skin cells. In addition, bilirubin-induced damage of cell membrane and nuclear membrane was also shown by transmission electron microscopy. Bilirubin (340 μM) in the dark led to 5% of the cells being killed. Basal skin cells bind 2.5 times more bilirubin molecules than lymphoid cells and showed a different bilirubin disappearance. Irradiation of bilirubin in carbon tetrachloride with 514.5 nm laser light showed generation of singlet oxygen via its luminescence at 1270 nm. These results demonstrate that green light phototherapy of hyperbilirubinemia may cause both skin and immune system damage.     

L-丙交酯-β-苹果酸共聚物的体外降解及细胞亲和性研究

研究了具有功能侧基的新型生物降解高分子——— [聚 (L 丙交酯 co β 苹果酸 ) ](PLMA)在pH 7 4的磷酸缓冲溶液中的降解和鼠的 3T3成纤维细胞在共聚物膜表面的贴附及生长 .研究了不同组成的共聚物在降解过程中的失重、表面形貌、组成及分子量变化 ,发现PLMA为本体降解 ,共聚物中苹果酸含量的提高可以加速降解 ,降解过程中聚苹果酸 (PMA)链段附近的酯键先水解断裂 .鼠的 3T3成纤维细胞在聚L 丙交酯 (PLLA)均聚物和苹果酸含量为 4mol% ,8mol%和 13mol%的共聚物膜上培养 5h ,细胞贴附率分别为 4 3%、71%、80 %和 4 3% .3T3成纤维细胞在苹果酸含量为 4mol%和 8mol%的共聚物膜上的生长情况好于在PLLA均聚物和苹果酸含量为 13mol%含量的共聚物膜上的生长 .     

In vitro PHOTOSENSITIZING PROPERTIES OF RHODAMINE 123 ON DIFFERENT HUMAN TUMOR CELL LINES

Abstract— In this study, human tumor cell lines of different origin (colon carcinoma HT29, breast carcinoma MCF7 and malignant melanoma M14) were incubated for 24 h at 37*deg;C with Rhodamine 123 (Rh123) at concentrations ranging up to 4 μg/ml;. Immediately after drug removal, light irradiation was delivered at 500 W/m² for 5 min using an argon laser. After irradiation, viable cells were counted and assayed for colony formation. When only Rh123 was administered, a 50% survival was obtained at about 2.77 μg/ml and 1.48 μg/ml; for HT29 and MCF7, respectively. After light irradiation, 50% survival doses decreased to 0.47 μg/ml and 0.18 μg/ml for the two carcinoma cell lines, respectively. In the case of malignant melanoma, the decrease in survival was relatively lower than those obtained with carcinoma cells: 50% survival dose was 3.54 μg/ml with Rh123 alone and 1.32 μ/ml after irradiation. The lower sensitivity of M14 melanoma cells seems to be related to different uptake and release of drug by these cells with respect to carcinoma lines.     

A STRATEGY FOR ISOLATING DIFFERENTIATIONINDUCING COMPLEMENTARY DNAs FROM HUMAN ESOPHAGEAL CANCER CELL LINE TREATED WITH RETINOIC ACID

Treatment of the human esophageal cancer cell line EC8712 with retinoic acid (RA) stopped the cell growth significantly and gave rise to terminal differentiation of the cells characterized by increased expression of involucrin gene. Two cDNA libraries were constructed from the parental and RA-treated cells respectively. Repeated subtractive hybridization of single-stranded plasmid DNA prepared from pooled colonies of cDNA library of the parental cells with cDNA probe generated from the RA-treated cells exhausted sequences common to both libraries of the cell. The unhybridized cDNA probe represented, therefore, the genes activated after RA-treatment. By using these enriched cDNAs as probe to screen the cDNA library constructed from the RA-treated cells thirty-nine positive colonies were obtained, of which two were specifically due to RA-induction. One of these two cDNA clones, designated as pRA538, has undergone further analysis and shown differentiation-inducing effect on parental cancer cells. A novel     

ASCORBIC ACID GLYCATION OF LENS PROTEINS PRODUCES UVA SENSITIZERS SIMILAR TO THOSE IN HUMAN LENS

-Soluble calf lens proteins were extensively glycated during a 4 week incubation with ascorbic acid in the presence of oxygen. Amino acid analysis of the dialyzed proteins removed at weekly intervals showed an increasing loss of lysine, arginine and histidine, consistent with the extensive protein cross-linking observed. Irradiation of the dialyzed samples with UVA light (1.0 kJ/cm² total illumination through a 338 nm cutoff filter) caused an increasing loss of tryptophan, an additional loss of histidine and the production of micromolar concentrations of hydrogen peroxide. No alteration in amino acid content and no photolytic effects were seen in proteins incubated without ascorbic acid or in proteins incubated with glucose for 4 weeks. The rate of hydrogen peroxide formation was linear with each glycated sample with a maximum production of 25 nmol/mg protein illuminated. The possibility that the sensitizer activity was due to an ascorbate-induced oxidation of tryptophan was eliminated by the presence of a heavy metal ion chelator during the incubation and by showing equivalent effects with ascorbate-incubated ribonuclease A, which is devoid of tryptophan. The ascorbate-incubated samples displayed increasing absorbance at wavelengths above 300 nm and increasing fluorescence (340/430) as glycation proceeded. The spectra of the 4 week glycated proteins were identical to those obtained with a solubilized water-insoluble fraction from human lens, which is known to have UVA sensitizer activity. The incubation of lens proteins with dehydroascorbic acid or l -threose, but not fructose, produced equivalent glycation, protein crosslinking and sensitizer activity. The relative sensitizer activity of the 4 week glycated sample was quantitatively very similar to that of a water-insoluble fraction from aged human lenses. These data are consistent with the hypothesis that the protein-bound brunescence in the lens may be advanced glycation endproducts, which are formed in large part by the oxidation products of ascorbic acid, and that these compounds may contribute significantly to the UVA sensitizer activity present in aged human lenses.     

TARGETING OF PHOTOTOXIC DRUGS TO ANTIGEN-SPECIFIC T LYMPHOCYTES in vitro USING ANTIGEN-PRESENTING CELL MEMBRANES

We have used the complex of antigen with class II major histocompatibility proteins (la) in membrane-bound form to target a phototoxic compound to antigen-specific T cell hybridomas in vitro. The iodoacetamidyl ester of phototoxic pyrene was bound covalently to antigen-presenting cells (APC), and protein antigens were added to the cells for processing, presentation and targeting of the drug to three different T hybridomas specific for myelin basic protein (MBP), ovalbumin (OVA) and keyhole limpet hemocyanin (KLH). The B hybridoma LS102.9 was used as APC to present MBP, KLH and either a tryptic digest of OVA or the synthetic peptide OVA323–339to these T cells. A transformed B lymphoma, which expresses trinitrophenol (TNP)-specific surface IgM, A20-HL, was used to present TNP conjugates of KLH and OVA to T cells. Either the antigen-bearing intact APC or Ia⁺ membranes shed spontaneously from them were used as drug carriers to target pyrene to the T cells. In the dark, or in the absence of pyrene, both the intact APC or the shed membranes stimulated interleukin-2 (IL-2) production by the T cells in an antigen-specific way. After UVA (320–400nm) irradiation, both forms of these drug carriers had an antigen-specific toxic effect on the T hybridoma cells with receptors for the antigen that they carried. Both spontaneous T cell proliferation and antigen-induced IL-2 production were inhibited. The shed membranes had a more antigen-specific toxic effect than the intact APC, which tend to settle out with the T cells in the microtiter plates, possibly causing nonspecific contact. These results indicate that the antigen-la complex in membrane-bound form can be used to antigen-target cytotoxic drugs to antigen-specific T cells. The Ia⁺ membranes shed from APC may be useful to target drugs to antigen-specific clones of T cells in vivo.     

PHOTOSENSITIZATION BY PORPHYRINS DELIVERED TO L CELL FIBROBLASTS BY HUMAN SERUM LOW DENSITY LIPOPROTEINS. A MICROSPECTROFLUOROMETRIC STUDY

Human serum LDL were used as vehicles to deliver protoporphyrin and hematoporphyrin dimer to L cell mouse fibroblasts. Topographic analysis by microspectrofluorometry on single living cells shows that after digestion of LDL, protoporphyrin is localized in cytoplasmic areas. Protoporphyrin and hematoporphyrin dimer are readily bleached by 420 ± 60 nm radiations at the high fluence rate used. Complex bleaching kinetics are observed. Spectral studies using the same technique demonstrate that an intense fluorescent emission (λ_max= 450 nm) is produced immediately after the onset of irradiation with 365 ± 2 nm or 420 ± 60 nm radiations using LDL loaded with protoporphyrin or Photofrin II. These fluorescent products have been previously identified as lipofuscin-like pigments formed by reaction of lipid photoperoxides with amino groups. The permeation of lysosomal membranes is also induced after delivery of the porphyrins by LDL. This permeation can be strongly inhibited not only by the lysosomal inhibitors chloroquine and monensin but also by a-tocopherol. On the other hand, neither α-tocopherol nor chloroquine or monensin inhibit the lipofuscin-like pigment formation.     

Cis-UROCANIC ACID DOWN-REGULATES THE INDUCTION OF ADENOSINE 3'', 5''-CYCLIC MONOPHOSPHATE BY EITHER trans-UROCANIC ACID OR HISTAMINE IN HUMAN DERMAL FIBROBLASTS in vitro

It has been demonstrated that UVB radiation (290-320 nm) suppresses mammalian cell-mediated immunity by effecting the trans to cis isomerization of urocanic acid (UCA) in the stratum corneum, the uppermost layer of the skin. Trans-urocanic acid has been shown to be the photoreceptor for UVB-induced immune suppression and the cis-isomer has been demonstrated to be immunosuppressive. Little is known, however, about how the isomerization of UCA may affect the proximal or distal cells of the skin or the immune system. We report here that trans-UCA is biologically active in vitro in human dermal fibroblasts, inducing adenyl cyclase as measured by cAMP (adenosine 3',5'-cyclic monophosphate) formation in a dose-dependent manner similar to the action of histamine. Trans-UCA and histamine stimulate 50% of maximum activity at concentrations of 3.3 microM and 13.8 microM respectively. Cis-UCA does not increase cAMP in these human fibroblasts but actively down regulates the increase of cAMP induced by either histamine or trans-UCA. Cis-UCA down regulated the histamine response by 75% and the trans-UCA response by 60% at a concentration range of 1 mM to 1 nM. The trans-UCA induction of cAMP can also be downregulated with an H2 histamine receptor antagonist cimetidine. These results support the hypothesis that a cellular target for cis-UCA is the dermal fibroblast and the effects reported here may represent the initial biochemical and cellular event for UVB-induced immune suppression i.e. the immediate step following the isomerization of trans to cis-UCA is the down regulation of cAMP by cis-UCA. Regulation of such an important second messenger such as cAMP could then allow cascading signals to occur, leading to immune suppression.     

ACTION SPECTRA FOR THE trans TO cis PHOTOISOMERISATION OF UROCANIC ACID in vitro and IN MOUSE SKIN

Urocanic acid (UCA) is a major UV chromophore in the upper layers of the skin where it is found predominantly as the trans isomer. UV irradiation induces photoisomerisation of trans-UCA to cis-UCA which has been shown to mimic some of the immunosuppressive properties of UV exposure. We examined the wavelength dependence for trans-UCA to cis-UCA photoisomerisation in vitro and in mouse skin in vivo over the spectral range270–340 nm. The resulting action spectra were very similar with maximal effectiveness at300–315 nm and equal activity at 270 nm and325–330 nm, demonstrating that UVA-II radiation (320–340nm) is efficient at UCA photoisomerisation. These action spectra differed markedly from the trans-UCA absorption spectrum in vitro and also the reported action spectrum for UV suppression of contact hypersensitivity in mice. These findings suggest that the relationship between cis-UCA formation in skin and UV-induced immunosuppression may be complex.     

SUNSCREENS WITH BROAD-SPECTRUM ABSORPTION DECREASE THE trans TO cis PHOTOISOMERIZATION OF UROCANIC ACID IN THE HUMAN stratum corneum AFTER MULTIPLE UV LIGHT EXPOSURES

Abstract The trans to cis photoisomerization of urocanic acid (UCA) in skin is considered to play an important role in the mechanism of immunosuppression. We have investigated the effects of skin type and various sunscreens with low sun protection factor (SPF) on the UV-induced cis -UCA formation in human skin after exposure to artificial IJV light. The rate of cis -UCA formation depends little on the skin type and is reduced by topical application of sunscreens. The rate of cis -UCA formation decreases with increasing SPF and only broad-spectrum, highly protective sunscreens offer protection against the UV-induced formation of cis -UCA, which accumulates in the stratum corneum after multiple UV exposures. A theoretical approach to estimate the distribution of cis -UCA after irradiation indicates that this compound may diffuse into the deeper layers of the epidermis with D ∼ 10⁻¹⁷ m²/s, and that its elimination from the stratum corneum is mainly due to desquamation.     

Cis-UROCANIC ACID SYNERGIZES WITH HISTAMINE FOR INCREASED PGE2 PRODUCTION BY HUMAN KERATINOCYTES: LINK TO INDOMETHACIN-INHIBITABLE UVB-INDUCED IMMUNOSUPPRESSION

Abstract— There is considerable evidence that suppression of the immune system by UVB (280–320 nm UV) irradiation is initiated by UVB-dependent isomerization of a specific skin photoreceptor, urocanic acid (UCA), from the trans to the cis form. Previous studies have confirmed that cis -UCA administration to mice 3–5 days prior to hapten sensitization at a distant site, suppresses the contact hypersensitivity (CHS) response upon challenge. This study demonstrates in mice that cis -UCA, like UVB, suppresses CHS to trinitrochlorobenzene by a mechanism partly dependent on prostanoid production. In vitro experimentation showed that human keratinocytes, isolated from neonatal foreskin, increased prostaglandin E₂ (PGE₂) production in response to histamine but not UCA alone. However, cis -UCA synergized with histamine for increased PGE₂ production by keratinocytes. cis -urocanic acid also increased the sensitivity of keratinocytes for PGE₂ production in response to histamine. Prostaglandin E₂ from keratinocytes exposed to cis -UCA and histamine may contribute directly, or indirectly, to the regulation of CHS responses by UVB irradiation.     

SURFACE MULTI-FUNCTIONALIZATION OF POLY(LACTIC ACID) NANOPARTICLES AND C6 GLIOMA CELL TARGETING in vivo

Polysaccharide coated PLA nanoparticles bearing aldehyde groups were prepared by dialysis of DMSO solution of cholesterol hydrophobic-modified dextran polyaldehyde and PLA against water.The average diameter of the nanoparticles was about 160 nm,and the size distribution was nearly homogenous.The nanoparticles were functionalized simultaneously with CD71 and EGFR antibody through the Schiff's base reaction,and then radiolabeled with ~(99m)Tc.After perfused the radiolabeled nanoparticles into tumor-bearing...     

PHOTOSENSITIZATION BY PHOTOFRIN II DELIVERED TO WI26VA4 SV40-TRANSFORMED HUMAN FIBROBLASTS BY LOW DENSITY LIPOPROTEINS: INHIBITION OF LIPID SYNTHESIS AND FATTY ACID UPTAKE

Irradiation with 365 nm light of Wi26VA4 SV40-transformed human fibroblasts cultured for 24 h in the presence of low density lipoproteins loaded with the anticancer porphyrin mixture Photofrin II resulted in a near complete inhibition of [14C]oleic acid incorporation into triacylglycerols, cholesteryl esters and phospholipids. More than 80% reduction of the fatty acid incorporation in all lipid classes was observed following an irradiation dose of 1 J/cm2. The activities of the respective acyltransferases, measured in vitro on cell homogenates, were also markedly diminished, but to a lesser extent than lipid synthesis from oleic acid. Moreover, oleic acid uptake by cells was strongly and rapidly reduced. It is suggested that the rapid inhibition of membrane phospholipid synthesis upon cell photosensitization, due to both a direct inactivation of acyltransferases and to a reduction of fatty acid utilization, could play an important role in the photocytotoxic effect of Photofrin II.     

ULTRAVIOLET RADIATION INDUCES A CHANGE IN CELL MEMBRANE POTENTIAL in vitro: A POSSIBLE SIGNAL FOR ULTRAVIOLET RADIATION INDUCED ALTERATION IN CELL ACTIVITY

The regulation of a transmembrane ionic gradient, reflected by the cellular membrane potential, has been shown in several cell systems to be involved in the regulation of cell function. This investigation presents evidence that biologically relevant doses of ultraviolet radiation (UVR) will alter the membrane potential of keratinocytes in vitro. Estimation of the relative change in the steady-state membrane potential of the murine keratinocyte cell line PAM 212, the murine myelomonocytic cell line P388D1, and normal human keratinocytes in culture, were made through the use of the lipophilic cationic membrane potential sensitive probe; triphenylmethylphosphonium. Our observations indicate that UVR composed primarily of UVB (280-320 nm) radiation at doses as low as 100 J/m2 can induce a depolarization in the murine cell lines and a hyperpolarization in human keratinocytes. Evidence suggests that this difference in the direction of the membrane potential response reflects a difference in Na+/K+ ATPase activity following UVR. These results suggest a possible mechanism for modulation of keratinocyte activity induced by UVR.     

In vitro AND in vivo UPTAKE OF BENZOPORPHYRIN DERIVATIVE INTO HUMAN AND MINISWINE ATHEROSCLEROTIC PLAQUE

Abstract— Befnzoporphyrin derivative(BPD) has been demonstrated to be fnew potent photosentsitze for photodynamic therapy(PDT). Althought most of wrok on BPD has been focused on its potential applications for cancer tratment, BPD amy have potential clilnical uses in the treatment of artheros clerosis. The purposes of this study was to determine in vitro and vivo uptake of BPD into atherosclerotic plaque. Samples of atherosclerotic human femoral and popliteal arteries were incubated with BPD-monoacid, ring A(BPD-MA) for 1 h in the following concentrations: 1, 5, 10, 20, 30 and 40 μg/mL. fluorescence from all samplesd was determined by chemical etraction with a spectrofluorometer. the tissue concentration for human arteries was 0.37 ± 0.03, 2.78 ± 1.5, 3.6 ± 1.91, 7.15 ± 2.36, 8.06 ± 3.09 and 14.6 ± 4.81 μg/g, respectively. In aeddition, three miniswine were rendered atherosclerotic and given BPD 2.0 mg/ Kg intravenously. The concentration of BPD-MA in miniswine aorta was93–190 ng/g and the plaque/normal ration was 1.7–3.5, for miniswine cartoid artery contained 54 ng/g. this study showed that BPD-MA was taken up in atherosclerotic vesselsd both in vitro and in vivo and mey have potential for PDT of atherosclerosis.     

In vitro DEMONSTRATION OF A FUNDAMENTAL DIFFERENCE IN THE PROLIFERATION OF MURINE and HUMAN BONE MARROW and LYMPHOCYTES FOLLOWING ULTRAVIOLET IRRADIATION: RELEVANCE TO BONE MARROW TRANSPLANTATION

Exposure of rodent allogeneic donor marrow and splenocyte grafts to ultraviolet radiation (UVR) has been shown to permit durable engraftment at doses that abolish graft-versus-host disease (GVHD) and graft rejection. We have compared both murine and human alloreactive and mitogen-induced lymphoid responses and bone marrow proliferation in mixed lymphocyte culture (MLC), phy-tohemagglutinin (PHA)-induced proliferation and colony-forming unit-granulocyte/macrophage (CFU-GM) assays using germicidal UVC (200–290nm), broadband and narrowband UVB (290–320nm) and UVA (320^100 nm) sources. Our data show a wavelength and dose-dependent reduction in lymphoid proliferation in the mouse with CFU-GM survival of50–75% of control at doses required to abolish allogeneic lymphocyte responses for all lamps. In contrast, human lymphocyte responses are more resistant to UVC with CFU-GM proliferation reduced to zero when allostimulation is abolished. Mito-gen-induced lymphoid responses show a similar wavelength-dependent sensitivity. Abolition of response in MLC using UV-irradiated stimulator cells was less sensitive than proliferation with UV-irradiated responder cells at all wavelengths in both species. With all sources, murine CFU-GM proliferation is less susceptible to UVR than human marrow at doses required to abolish lymphoid responses.     

PHOTODYNAMIC THERAPY OF HUMAN BLADDER CANCER CELLS in vitro CORRELATED WITH CELLULAR FLUORESCENCE LEVELS OF PHOTOFRIN-II

Abstract In order to determine optimum dose of Photofrin-II (PHI) timing and dose of laser therapy and differential effects of laser on normal and neoplastic human bladder cancer cells in vitro , experiments were carried out using 3 cell lines of human bladder cancer (253-J, 639-V, and 647-V) and a human fibroblast line (CRL-1507). Cellular Pf-II uptake and excretion studied using flow cytometric fluorescence analysis of the cells and fluorescence levels of the culture medium showed a wide variability of uptake of Pf-II among the cell lines. Pf-II excretion occurred most rapidly in the first 4 h after incubation reaching maximum at 24-48 h in all cells studied. Cellular concentration of Pf-II and supernatant levels of Pf-II estimated by fluorescence levels had a reciprocal correlation. Laser treatment of one cancer line and the fibroblast line at 20 J (630 nm) at various times after incubation with 50 μ.g m^−l of Pf-II showed that the photodynamic effect correlated directly with cellular fluorescence. These results suggest that in vitro: (1) initial uptake of Pf-II is generally higher in neoplastic than normal cells but that excretion rates are similar; and (2) photodynamic effect is related primarily to initial cellular levels of photosensitizer rather than differential excretion rates.