Security of capsular fixation: small-versus large-hole plate-hepatic lenses

PURPOSE

To assess the effect of relatively large positioning holes on the security of capsular bag fixation of plate-haptic silicone intraocular lenses (IOLs).

SETTING

Center for Research on Ocular Therapeutics and Biodevices, Department of Ophthalmology, Storm Eye Institute, Medical University of South Carolina, Charleston, South Carolina, USA.

METHODS

This study tested the hypothesis that larger holes allow ingrowth of lens material, fibrous tissue, or both through them, which helps fixate the lens more firmly in the capsular bag. Five rabbits had bilateral continuous curvilinear capsulorhexis, phacoemulsification, and implantation of a plate-haptic silicone IOL. An IOL with a small, round positioning hole (Staar AA-4203V) was implanted in the right eye in each rabbit, and a large-hole IOL (Staar AA-4203VF) was implanted in the left eye. After 2 months, all rabbits were killed. The force required to extract one haptic from the capsular bag was measured with a digital force meter. All eyes had histopathological analysis.

RESULTS

It was slightly more difficult to extract a large-hole IOL from the capsular bag, although this trend was not statistically significant. However, histopathological analysis consistently showed 360 degree synechia formation through the holes, showing that the IOL could be securely fixed in position.

CONCLUSIONS

Proliferation of lens epithelial cells through a large positioning hole in a plate-haptic silicone IOL may improve the long-term security of capsular bag fixation. This will help reduce the incidence of IOL decentration and dislocation.

[Studies on expansion ex vivo of murine bone marrow cells and its hematopoietic reconstitution capacity]

OBJECTIVE

To investigate the effects of stem cell factor (SCF) in combination with interleukin-1 (IL-1) or/and interleukin-3 (IL-3) on ex vivo expansion of 5FU treated bone marrow cells and hematopoietic recovery in lethally irradiated mice transplanted with the expanded cells.

METHODS

5FU treated bone marrow cells (d3-5FU-BMC) were cultured in a cytokines-containing medium, and the net increments of CFU-GM and high proliferative potential colony forming cell (HPP-CFC) were evaluated.

RESULTS

CFU-GM increased by 33.7 +/- 18.1- or 18.1 +/- 6.3- fold, and HPP-CFC by 17.8 +/- 10.5- or 12.7 +/- 9.1- fold, respectively, in cultures containing SCF with IL- or IL-3, as compared with that in control; while SCF alone had little effect. Compared with fresh d3-5FU-BMC, transplantation of the expanded bone marrow cells accelerated the recovery of recipients' peripheral blood cell counts by 1 approximately 3 days and increased the survival rate of the transplanted animals (d3-5FU-BMC group 50% vs expansion group 8U approximately 100%).

CONCLUSION

SCF in combination with IL-1 or IL-3 synergetically ex vivo expands hematopoietic cells. Transplantation of the expanded bone marrow cells accelerates the recipient's hematopoietic reconstitution.

5-Aminolevulinic acid-based photodynamic therapy. Clinical research and future challenges

BACKGROUND

Photodynamic therapy (PDT) for cancer patients has developed into an important new clinical treatment modality in the past 25-years. PDT involves administration of a tumor-localizing photosensitizer or photosensitizer prodrug (5-aminolevulinic acid [ALA], a precursor in the heme biosynthetic pathway) and the subsequent activation of the photosensitizer by light. Although several photosensitizers other than ALA-derived protoprophyrin IX (PpIX) have been used in clinical PDT, ALA-based PDT has been the most active area of clinical PDT research during the past 5 years. Studies have shown that a higher accumulation of ALA-derived PpIX in rapidly proliferating cells may provide a biologic rationale for clinical use of ALA-based PDT and diagnosis. However, no review updating the clinical data has appeared so far.

METHODS

A review of recently published data on clinical ALA-based PDT and diagnosis was conducted.

RESULTS

Several individual studies in which patients with primary nonmelanoma cutaneous tumors received topical ALA-based PDT have reported promising results, including outstanding cosmetic results. However, the modality with present protocols does not in general, appear to be superior to conventional therapies with respect to initial complete response rates and long term recurrence rates, particularly in the treatment of nodular skin tumors. Topical ALA-PDT does have the following advantages over conventional treatments: it is noninvasive; it produces excellent cosmetic results; it is well tolerated by patients; it can be used to treat multiple superficial lesions in short treatment sessions; it can be applied to patients who refuse surgery or have pacemakers and bleeding tendency; it can be used to treat lesions in specific locations, such as the oral mucosa or the genital area; it can be used as a palliative treatment; and it can be applied repeatedly without cumulative toxicity. Topical ALA-PDT also has potential as a treatment for nonneoplastic skin diseases. Systemic administration of ALA does not seem to be severely toxic, but the advantage of using this approach for PDT of superficial lesions of internal hollow organs is still uncertain. The ALA-derived porphyrin fluorescence technique would be useful in the diagnosis of superficial lesions of internal hollow organs.

CONCLUSIONS

Promising results of ALA-based clinical PDT and diagnosis have been obtained. The modality has advantages over conventional treatments. However, some improvements need to be made, such as optimization of parameters of ALA-based PDT and diagnosis; increased tumor selectivity of ALA-derived PpIX; better understanding of light distribution in tissue: improvement of light dosimetry procedure; and development of simpler, cheaper, and more efficient light delivery systems.

5-Aminolevulinic acid-based photodynamic therapy. Clinical research and future challenges

BACKGROUND

Photodynamic therapy (PDT) for cancer patients has developed into an important new clinical treatment modality in the past 25-years. PDT involves administration of a tumor-localizing photosensitizer or photosensitizer prodrug (5-aminolevulinic acid [ALA], a precursor in the heme biosynthetic pathway) and the subsequent activation of the photosensitizer by light. Although several photosensitizers other than ALA-derived protoprophyrin IX (PpIX) have been used in clinical PDT, ALA-based PDT has been the most active area of clinical PDT research during the past 5 years. Studies have shown that a higher accumulation of ALA-derived PpIX in rapidly proliferating cells may provide a biologic rationale for clinical use of ALA-based PDT and diagnosis. However, no review updating the clinical data has appeared so far.

METHODS

A review of recently published data on clinical ALA-based PDT and diagnosis was conducted.

RESULTS

Several individual studies in which patients with primary nonmelanoma cutaneous tumors received topical ALA-based PDT have reported promising results, including outstanding cosmetic results. However, the modality with present protocols does not in general, appear to be superior to conventional therapies with respect to initial complete response rates and long term recurrence rates, particularly in the treatment of nodular skin tumors. Topical ALA-PDT does have the following advantages over conventional treatments: it is noninvasive; it produces excellent cosmetic results; it is well tolerated by patients; it can be used to treat multiple superficial lesions in short treatment sessions; it can be applied to patients who refuse surgery or have pacemakers and bleeding tendency; it can be used to treat lesions in specific locations, such as the oral mucosa or the genital area; it can be used as a palliative treatment; and it can be applied repeatedly without cumulative toxicity. Topical ALA-PDT also has potential as a treatment for nonneoplastic skin diseases. Systemic administration of ALA does not seem to be severely toxic, but the advantage of using this approach for PDT of superficial lesions of internal hollow organs is still uncertain. The ALA-derived porphyrin fluorescence technique would be useful in the diagnosis of superficial lesions of internal hollow organs.

CONCLUSIONS

Promising results of ALA-based clinical PDT and diagnosis have been obtained. The modality has advantages over conventional treatments. However, some improvements need to be made, such as optimization of parameters of ALA-based PDT and diagnosis; increased tumor selectivity of ALA-derived PpIX; better understanding of light distribution in tissue: improvement of light dosimetry procedure; and development of simpler, cheaper, and more efficient light delivery systems.

5-Aminolevulinic acid-based photodynamic therapy. Clinical research and future challenges

BACKGROUND

Photodynamic therapy (PDT) for cancer patients has developed into an important new clinical treatment modality in the past 25-years. PDT involves administration of a tumor-localizing photosensitizer or photosensitizer prodrug (5-aminolevulinic acid [ALA], a precursor in the heme biosynthetic pathway) and the subsequent activation of the photosensitizer by light. Although several photosensitizers other than ALA-derived protoprophyrin IX (PpIX) have been used in clinical PDT, ALA-based PDT has been the most active area of clinical PDT research during the past 5 years. Studies have shown that a higher accumulation of ALA-derived PpIX in rapidly proliferating cells may provide a biologic rationale for clinical use of ALA-based PDT and diagnosis. However, no review updating the clinical data has appeared so far.

METHODS

A review of recently published data on clinical ALA-based PDT and diagnosis was conducted.

RESULTS

Several individual studies in which patients with primary nonmelanoma cutaneous tumors received topical ALA-based PDT have reported promising results, including outstanding cosmetic results. However, the modality with present protocols does not in general, appear to be superior to conventional therapies with respect to initial complete response rates and long term recurrence rates, particularly in the treatment of nodular skin tumors. Topical ALA-PDT does have the following advantages over conventional treatments: it is noninvasive; it produces excellent cosmetic results; it is well tolerated by patients; it can be used to treat multiple superficial lesions in short treatment sessions; it can be applied to patients who refuse surgery or have pacemakers and bleeding tendency; it can be used to treat lesions in specific locations, such as the oral mucosa or the genital area; it can be used as a palliative treatment; and it can be applied repeatedly without cumulative toxicity. Topical ALA-PDT also has potential as a treatment for nonneoplastic skin diseases. Systemic administration of ALA does not seem to be severely toxic, but the advantage of using this approach for PDT of superficial lesions of internal hollow organs is still uncertain. The ALA-derived porphyrin fluorescence technique would be useful in the diagnosis of superficial lesions of internal hollow organs.

CONCLUSIONS

Promising results of ALA-based clinical PDT and diagnosis have been obtained. The modality has advantages over conventional treatments. However, some improvements need to be made, such as optimization of parameters of ALA-based PDT and diagnosis; increased tumor selectivity of ALA-derived PpIX; better understanding of light distribution in tissue: improvement of light dosimetry procedure; and development of simpler, cheaper, and more efficient light delivery systems.

Silicone oil adhesion to intraocular lenses: an experimental study comparing various biomaterials

PURPOSE

To perform an in vitro experimental study comparing the degree of adherence of silicone oil to various rigid and foldable intraocular lens (IOL) designs and to the human lens capsule.

SETTING

Center for Research on Ocular Therapeutics and Biodevices, Department of Ophthalmology, Storm Eye Institute, Medical University of South Carolina, Charleston, South Carolina, USA.

METHODS

Seven IOL styles comprising various biomaterials were studied: fluorine-treated (Fluorlens), heparin-surface-modified (HSM), hydrogel, Memory-Lens, Poly(methyl methacrylate) (PMMA), soft acrylic, and silicone lenses; the human crystalline lens was also studied. Each lens was immersed in silicone oil for 12 hours, than photographed, studied by scanning electron microscopy (except the crystalline lens), and subjected to computer-generated image analysis to determine the silicone oil coverage.

RESULTS

Silicone oil coverage of dry silicone lenses was 100% and of lenses immersed in normal saline, 82.5%. The least coverage was on the heparin-surface-modified lens (mean score 9.4%). Coverage of the other four lenses ranged from approximately 15.1% to 33.7%. Mean coverage of the human lens capsule was 10.9%.

CONCLUSION

Although a silicone IOL shows maximal adherence to silicone oil, other lens biomaterials are not immune to this complication. Silicone oil coverage was related to the dispersive energy component of the surface charge of the IOL biomaterial. Low dispersive energy materials had less silicone oil coverage, while those with higher dispersive energy had more oil coverage.

Use of 5-aminolevulinic acid esters to improve photodynamic therapy on cells in culture

Human tumor cells of the lines WiDr (adenocarcinoma of the rectosigmoid colon), NHIK 3025 (carcinoma of the cervix), and V79 Chinese hamster fibroblasts were treated with 5-aminolevulinic acid (ALA) and ALA esterified to C1-C3 and C6-C8 chained aliphatic alcohols (ALA-esters). In the human cell lines, esterification of ALA with the long-chain (C6-C8) alcohols was found to reduce 30-150-fold the amount of ALA needed to reach the same level of protoporphyrin IX (PpIX) accumulation as with non-esterified ALA. The long-chained ALA-esters were less efficient in stimulating PpIX formation in V79 cells, i.e., the same amount of PpIX was formed by a 1-2.6-fold lower concentration of long-chained ALA-esters than with ALA. Short-chained ALA-esters (C1-C3) induced 5 to 10 times lower PpIX accumulation than ALA in all of the cell lines. High-performance liquid chromatography and fluorescence microscopic studies indicated that esterification of ALA has neither impact on the fluorescing porphyrin species formed nor impact on their intracellular localization. The PpIX formed from ALA-esters and ALA was found to be equally efficient in sensitizing cells to photoinactivation. The present results indicate that esterified ALAs are new and promising drugs for use in photochemotherapy of cancer.

Effect of surface photorefractive keratectomy and laser in situ keratomileusis on the corneal endothelium

PURPOSE

To investigate endothelial cell loss in pairs of fresh human autopsy globes following high-diopter myopic photorefractive keratectomy (PRK) or laser in situ keratomileusis (LASIK).

SETTING

Center for Research on Ocular Therapeutics and Biodevices and Magill Laser Center for Vision Correction, Storm Eye Institute, Charleston, South Carolina, USA.

METHODS

In the first part of the study, 12 globes had either -10 diopters (D) multizone surface PRK or -10 D single-zone LASIK. In the second part, three groups of 5 globes each had -15 D, -20 D, or -25 D multizone-blend LASIK procedures. Fellow globes in both groups were used as untreated controls. Corneoscleral buttons were excised from all globes. Following 7 days in corneal organ culture, the endothelial surface was stained with two vital dyes: calcein-AM and ethidium homodimer. Fluorescence microscopy was used to obtain endothelial cell counts.

RESULTS

The mean dead cells per square millimeter (cells/mm2) were 0.94 in the -10 D PRK treated corneas compared with 0.91 in the fellow untreated eyes (P = 0.06(. The mean dead cells/mm2 in the -10 D single-zone LASIK-treated corneas and in the fellow untreated eyes were 0.61 (P = 0.88). The mean dead cells/mm2 in the -15 D, -20 D, and -25 D multizone-blend LASIK-treated corneas were 3.08, 2.33, and 5.55, respectively, compared with 3.49, 1.92, and 5.01 in the fellow untreated eyes (P = 0.276, P = 0.339, and P = 0.427, respectively). Dead cell counts for treated and control paired corneas were highly correlated in all treatment groups.

CONCLUSIONS

No significant endothelial cell loss occurred after -10 D PRK or LASIK corrections up to -25 D. Although this study has limitations that prevent direct extrapolation to the clinical situation, it does afford a comparable clinical correlate for endothelial cell toxicity following a typical excimer laser ablations.

[Molfig, a software for displaying the structure and vibration of molecule]

A Molfig software has been developed for displaying the structure and vibrational mode of molecule in our lab. Various functions and a friendly interface are equipped in the software. The testing results showed that the software may enhance our understanding of the relationship between the vibrational behavior and the structure of molecules.

[Curvefit, an overlapping bands resolving software for IR spectra]

A Curvefit software has been developed for resolving the overlapping band of the vibartional spectra in our lab . Various functions and a friendly interface are equipped in the software. The testing results showed that both the speed of the calculation and the reliability of the final results are satisfactory.

Pharmacokinetic studies on 5-aminolevulinic acid-induced protoporphyrin IX accumulation in tumours and normal tissues

Laser-induced fluorescence (LIF) for in vivo point monitoring and fluorescence microscopy incorporating a CCD camera were used to study the fluorescence distribution of 5-aminolevulinic acid (ALA)-induced protoporphyrin IX (PpIX) in tumours. Fluorescence in a chemically-induced adenocarcinoma in the liver of rats and in an aggressive basal cell carcinoma in a patient were studied after intravenous injection of ALA at a dose of 30 mg/kg body weight. The LIF technique demonstrated slightly more ALA-induced PpIX fluorescence in the tumour than in the surrounding normal liver and abdominal muscle of rats. The visible parts of the human basal cell carcinoma exhibited strong ALA-induced fluorescence, while this fluorescence was much weaker in the necrotic areas of the tumour and in the surrounding normal skin.

Characterization of the protein product encoded by a splicing variant of the Marek's disease virus Eco-Q gene (Meq)

In the present study, we report the characterization of a 212-amino-acid polypeptide encoded by a splicing variant of the Marek's disease virus Eco-Q gene (Meq). This protein, referred to as Meq-sp, contains the N-terminal 100 amino acids of Meq, which include part of Meq's DNA binding/dimerization domain, but lacks the transactivation domain of Meq. Thus, Meq-sp was examined for its ability to bind to DNA and act as a transactivator. Results indicated that while Meq and Meq-sp could both bind to the AP-1 binding site, the 110 C-terminal amino acid residues of Meq-sp lacked the ability to function as a transactivator when fused to the GAL4 (1-147) DNA binding motif. To investigate whether Meq-sp can interact with Meq or with c-jun, protein-protein and protein-DNA interactions in vitro were examined. Results showed that Meq-sp can associate with both Meq and c-jun and bind to the AP-1 site with a higher affinity as a heterodimer with c-jun. These results suggest that Meq-sp could compete with Meq for heterodimer formation with c-jun and dimer binding to DNA and possibly act as a transdominant negative regulator of Meq activity in vivo.

Isolation and characterization of Marek's disease virus (MDV) cDNAs from a MDV-transformed lymphoblastoid cell line: identification of an open reading frame antisense to the MDV Eco-Q protein (Meq)

Two Marek's disease virus (MDV) cDNAs of 852 and 1168 bp, which map to the right end of the BamHI-I2 fragment of the MDV genome, were isolated from a cDNA library derived from the MDV transformed lymphoblastoid cell line MKT-1. These cDNAs hybridized to relatively abundant leftward mRNA transcripts in MKT-1 cells and cells lytically infected with MDV. The transcriptional initiation site for these transcripts was located in the adjacent BamHI-Q2 fragment, as determined by RNase protection and primer extension assays. A computer search for the presence of leftward open reading frames (ORFs) revealed two ORFs encoding 135- and 195-amino-acid polypeptides. A polyclonal antibody raised against a protein sequence in the N-terminus of the latter ORF detected a 23-kDa protein in the nuclear fraction of MDV-transformed lymphoblastoid cells. Furthermore, this ORF was antisense to part of the MDV Eco-Q protein (Meq) sequence.

Autoimmune lpr/lpr mice deficient in CD40 ligand: spontaneous Ig class switching with dichotomy of autoantibody responses

Fas-deficient MRL/Mp-lpr/lpr mice develop a syndrome that resembles human systemic lupus erythematosus, including production of IgG autoantibodies against small nuclear ribonucleoproteins (snRNPs), dsDNA, and self IgG (rheumatoid factor). To investigate the necessity for T-B cell contact in MRL autoimmunity, mice deficient in CD40 ligand (CD40L) were backcrossed onto this background, and Ab synthesis was assessed. In comparison to their CD40L-intact lpr/lpr counterparts, CD40L-deficient lpr/lpr mice had elevated levels of serum IgM and lower levels of IgG; however, a subset of animals had IgG2a, and to a lesser extent, IgG2b levels similar to those found in wild-type lpr/lpr mice. Levels of both isotypes in CD40L-deficient lpr/lpr mice were significantly greater than those found in nonautoimmune CD40L-deficient animals. IgG autoantibodies, including those directed against small nuclear ribonucleoproteins, also arose in CD40L-deficient lpr/lpr mice; however, they did not develop IgG rheumatoid factors or anti-dsDNA, and lacked histologic evidence of overt glomerulonephritis at age 3 mo, in contrast to CD40L-intact lpr/lpr animals. These results indicate that isotype switching occurs in lpr/lpr mice deficient in CD40L, and that production of IgG autoantibodies to ribonucleoproteins is at least partially preserved. They also suggest that different mechanisms may be responsible for eliciting autoantibody responses in lpr/lpr mice.

Autoimmune lpr/lpr mice deficient in CD40 ligand: spontaneous Ig class switching with dichotomy of autoantibody responses

Fas-deficient MRL/Mp-lpr/lpr mice develop a syndrome that resembles human systemic lupus erythematosus, including production of IgG autoantibodies against small nuclear ribonucleoproteins (snRNPs), dsDNA, and self IgG (rheumatoid factor). To investigate the necessity for T-B cell contact in MRL autoimmunity, mice deficient in CD40 ligand (CD40L) were backcrossed onto this background, and Ab synthesis was assessed. In comparison to their CD40L-intact lpr/lpr counterparts, CD40L-deficient lpr/lpr mice had elevated levels of serum IgM and lower levels of IgG; however, a subset of animals had IgG2a, and to a lesser extent, IgG2b levels similar to those found in wild-type lpr/lpr mice. Levels of both isotypes in CD40L-deficient lpr/lpr mice were significantly greater than those found in nonautoimmune CD40L-deficient animals. IgG autoantibodies, including those directed against small nuclear ribonucleoproteins, also arose in CD40L-deficient lpr/lpr mice; however, they did not develop IgG rheumatoid factors or anti-dsDNA, and lacked histologic evidence of overt glomerulonephritis at age 3 mo, in contrast to CD40L-intact lpr/lpr animals. These results indicate that isotype switching occurs in lpr/lpr mice deficient in CD40L, and that production of IgG autoantibodies to ribonucleoproteins is at least partially preserved. They also suggest that different mechanisms may be responsible for eliciting autoantibody responses in lpr/lpr mice.

Apoptosis and necrosis induced with light and 5-aminolaevulinic acid-derived protoporphyrin IX

The mode of cell death induced by photodynamic treatment (PDT) was studied in two cell lines cultured in monolayer, V79 Chinese hamster fibroblasts and WiDr human colon adenocarcinoma cells. The cells were incubated with 5-aminolaevulinic acid (5-ALA) as a precursor for the endogenously synthesised protoporphyrin IX, which was activated by light. Free DNA ends, owing to internucleosomal DNA cleavage in apoptotic cells, were stained specifically with a fluorescent dye in the terminal deoxynucleotidyl transferase (TdT) assay. The free DNA ends were measured by flow cytometry and the fractions of apoptotic cells determined. Total cell death was measured in a cell survival assay to determine the necrotic fraction after subtraction of the apoptotic fraction. V79 cells did undergo apoptosis while WiDr cells were killed only through necrosis. With time, the apoptotic fraction of V79 cells increased until a maximum was reached about 3-4 h after ALA-PDT treatment. For increasing ALA-PDT doses, a maximal apoptotic fraction 75-85% of the cells was measured at about 85% of total cell death. The flow cytometric assay of apoptosis was confirmed by the typical ladder of oligonucleosomal DNA fragments obtained from agarose gel electrophoresis, by fluorescence micrographs visualising the induced free DNA ends and by electron micrographs showing the typical morphology of apoptotic cells.

Influenza A virus RNA-dependent RNA polymerase cleaves influenza mRNA in vitro

We have investigated the endonuclease activity of the influenza A virus RNA polymerase in an in vitro assay with an artificial influenza-like mRNA containing a cap structure at its 5' terminus, followed by a 10 nt beta-globin mRNA sequence, and the 5' and 3' conserved termini of a truncated nucleoprotein (NP) cRNA influenza sequence. Results showed that partially purified virion ribonucleoprotein complexes (RNPs) and micrococcal nuclease treated RNPs cleaved the artificial influenza-like mRNA substrate specifically at positions near the 5' terminus to generate capped 14 and 15 nucleotide long RNA fragments which subsequently served as primers to initiate transcription. The endonuclease activity was completely blocked by addition of cap analog and competitively inhibited by added globin mRNA. Furthermore, an in vitro reconstituted influenza RNA transcription reaction containing a truncated NP vRNA as template, micrococcal nuclease treated RNPs and globin mRNA as primer, synthesized capped and uncapped full length (+) sense products. Enzyme kinetics showed that capped RNA was made earlier in the reaction; it reached a peak at 120 min and then declined. However, uncapped cRNA synthesis appeared later and remained as the dominant product later in the reaction. The nature of these products was confirmed by ribonuclease protection assays and by primer extension.

Germinal center formation, immunoglobulin class switching, and autoantibody production driven by "non alpha/beta" T cells

The production of class-switched antibodies, particularly immunoglobulin (Ig) G1 and IgE, occurs efficiently in T cell receptor (TCR) alpha-/- mice that are congenitally devoid of alpha/beta T cells. This finding runs counter to a wealth of data indicating that IgG1 and IgE synthesis are largely dependent on the collaboration between B and alpha/beta T cells. Furthermore, many of the antibodies synthesized in TCR alpha-/- mice are reactive to a similar spectrum of self-antigens as that targeted by autoantibodies characterizing human systemic lupus erythematosus (SLE). SLE, too, is most commonly regarded as an alpha/beta T cell-mediated condition. To distinguish whether the development of autoantibodies in TCR alpha-/- mice is due to an intrinsic de-regulation of B cells, or to a heretofore poorly characterized collaboration between B and "non-alpha/beta T" cells, the phenotype has been reconstituted by transfer of various populations of B and non-alpha/beta T cells including cloned gamma/delta T cells derived from TCR alpha-/- mice, to severe combined immunodeficient (SCID) mice. The results establish that the reproducible production of IgG1 (including autoantibodies) is a product of non-alpha/beta T cell help that can be provided by gamma/delta T cells. This type of B-T collaboration sustains the production of germinal centers, lymphoid follicles that ordinarily are anatomical signatures of alpha/beta T-B cell collaboration. Thus, non-alpha/beta T cell help may drive Ig synthesis and autoreactivity under various circumstances, especially in cases of alpha/beta T cell immunodeficiency.

Influenza A virus RNA-dependent RNA polymerase: analysis of RNA synthesis in vitro

Influenza A virus RNA-dependent RNA polymerase, purified from virion ribonucleoprotein particles and from which endogenous genomic RNA (vRNA) has been depleted by treatment with micrococcal nuclease, was used to study transcription initiation, elongation, and termination in vitro. Templates that contained either minus- or plus-sense influenza virus nucleoprotein minigenes with conserved 5' and 3' termini and the uridylate tract were constructed. The dinucleotide ApG and alfalfa mosaic virus RNA4 (AlMV4) were used as primers. ApG primed the synthesis of full-length positive-strand or cRNA products and shorter transcripts, depending upon the molar ratio between the nucleoprotein and the vRNA template. Sequence analysis of the ends of these transcripts demonstrated that the 5' termini of both transcripts and the 3' terminus of the full-length product were complementary to the 3' and 5' termini of the vRNA template, respectively, whereas the 3' terminus of the incomplete product corresponded to a sequence located 40 bases downstream from the 5' terminus of the template and was about 20 nucleotides downstream from the uridylate tract, which is the putative signal for polyadenylation. Binding of the cap structure of AlMV4 by the polymerase activated RNA synthesis by ligation-elongation of small genomic RNA fragments which were likely derived from a genome segment protected by the polymerase from micrococcal nuclease digestion. The sequence of these fragments mapped to a region 14 to 28 nucleotides upstream of the 3' terminus of the viral genome. Polymerase subunit involvement in transcription initiation with ApG or AlMV4 was characterized by studying the effect of purified polyclonal antisubunit immunoglobulins of the G class (IgGs) in transcription assays. These results showed that anti-PB2 IgG inhibited transcription initiation in both ApG- and AlMV4-primed reactions, whereas anti-PB1 antibodies also blocked transcription initiated with AlMV4. The differences observed in product size, product sequence, and differential inhibition by antisubunit IgGs are discussed. These observations would support the notion that the influenza virus RNA-dependent RNA polymerase undergoes a conformational change after the binding of the cap structure of host cell heterogeneous nuclear RNA by PB2, which then usually leads to endonucleolytic cleavage of the capped primer 13 nucleotides downstream from the cap.

Correlation of subcellular and intratumoral photosensitizer localization with ultrastructural features after photodynamic therapy

Photodynamic therapy (PDT) of cancer typically involves systemic administration of tumor-localizing photosensitizers followed 48-72 h later by exposure to light of appropriate wavelengths. Knowledge about the distribution of photosensitizers in tissues is still fragmentary. In particular, little is known as to the detailed localization patterns of photosensitizers in neoplastic and normal tissues as well as the relationship between such patterns and the actual targets for the photosensitizing effect. This review focuses on ultrastructural features seen in treated cells and tumors. An attempt is made to correlate these findings with the subcellular/intratumoral localization pattern of the photosensitizers in tumor cell lines in vitro and in tumor models in vivo. Several subcellular sites are main targets of PDT with different sulfonated aluminum phthalocyanines (AIPcSn) in the human tumor cell line LOX. Nuclei are not among the primary targets. Overall, the ultrastructural changes correlate well with the data about the subcellular localization patterns for each analogue of AIPcSn in the same cell line. Similar findings are also obtained for the family of sulfonated mesotetraphenylporphines (TPPSn) in the NHIK 3025 cell line. The mechanisms involved in the killing of tumors by PDT seem to be a complex interplay between direct and indirect (via vascular damage) effects on neoplastic cells according to the intratumoral localization pattern of the applied dye. Several factors can affect the localization pattern of a drug, such as its chemical character, the mode of drug delivery, the time interval between drug administration and light exposure, and tumor type. Furthermore, whether local immune reactions (such as macrophages) and apoptosis (programmed cell death) are involved in the destruction of neoplastic cells by PDT in vivo is still an enigma. A general model for PDT-induced tumor destruction is suggested.

Isolation and characterization of Marek's disease virus (MDV) cDNAs mapping to the BamHI-I2, BamHI-Q2, and BamHI-L fragments of the MDV genome from lymphoblastoid cells transformed and persistently infected with MDV

We have isolated and sequenced two cDNAs of sizes 2674 and 677 bp from a cDNA library derived from MKT-1, a lymphoblastoid cell line transformed and latently infected with Marek's disease virus (MDV) using probes corresponding to the right-hand end of the BamHI-I2 fragment of the MDV genome. The larger cDNA clone represents an abundant transcript, which extends from the right-hand end of BamHI-I2 to the adjacent BamHI-Q2 and BamHI-L fragments of the MDV genome and contains the Meq (MDV Eco-Q) open reading frame. The smaller cDNA clone represents a spliced transcript containing the putative DNA binding domain of Meq as well as sequences in the BamHI-L region. We prepared a polyclonal antibody against part of the protein sequence of Meq and detected a 44-kDa protein in MKT-1 cells and in cells lytically infected with MDV. In addition, riboprobes corresponding to sequences specific to each cDNA as well as shared sequences between cDNAs detected a number of transcripts in cells either lytically or latently infected with MDV. Our results indicate that the Meq transcriptional unit extends to the BamHI-L fragment and that the transcripts mapping to the right-hand end of the BamHI-I2 and adjacent BamHI-Q2 and BamHI-L fragments are not preferentially expressed during latency.

Distribution of 5-aminolevulinic acid-induced porphyrins in noduloulcerative basal cell carcinoma

Microscopic fluorescence photometry incorporating a light-sensitive thermo-electrically cooled charge-coupled device (CCD) camera was employed to investigate the fluorescence distribution of 5-aminolevulinic acid (ALA)-induced porphyrins in 22 patients with a total number of 52 noduloulcerative basal cell carcinomas (BCC) after topical ALA application with or without dimethylsulfoxide (DMSO)/ethylenediaminetetraacetic acid (EDTA) or after intravenous administration of ALA. Both localization patterns and amounts of ALA-induced porphyrins in the BCC were studied. The ALA-induced porphyrins were localized only in the superficial layers of the noduloulcerative BCC lesions after topical application of 20% ALA alone for 3 h. However, both the penetration of ALA into deep lesions and the production of the ALA-induced porphyrin fluorescence were increased after topical administration of 20% ALA and 20% DMSO/4% EDTA for 3 h. Prior treatment with 99% DMSO for 15 min further enhanced the ALA penetration into the BCC lesions after topical application of the ALA/DMSO/EDTA mixture and produced more ALA-induced porphyrins by a factor of about three compared with those treated with ALA alone. The penetration of ALA into the deep BCC lesions could also be increased by prolonging the time of topical application of 20% ALA/4% EDTA to 29-48 h (without DMSO). Intravenous injection of ALA led to a more homogeneous distribution of the ALA-derived porphyrins in the whole noduloulcerative BCC lesions.

The rise and prospects of medical aesthetics

Since the 1980s, Chinese scholars have been trying to expound and synthetise elementary aesthetical ideas which occur in medicine, in order to treat this area of study as a defined branch of medicine--'medical aesthetics'. It is in this context that the points discussed in this paper arise. We set forth in detail the ideas, objectives and methods adopted within the framework of medical aesthetics and its applied branch--medical cosmetology and expound the relations between them. We think the task of medical aesthetics is to study the human body in its entirety, concentrating on both internal and external beauty and put the findings into practice, whereas the task of medical cosmetology is to study and assess only the external beauty of the human body and to take action on that basis. Medical cosmetology is the enforcement of medical aesthetics, practised in order to give positive results connected with physical beauty, and is therefore easily understood by the layman. It is known that the development of medical cosmetology represents an important breakthrough in the development of medical aesthetics. We think that beauty should not be measured mechanically, always following the same pattern, but that it should be considered individually with everyone's own particular characteristics. The quality of physical attractiveness should be assessed jointly by the doctor and his patient or client, not solely by either of these individuals nor even by a group of doctors.(ABSTRACT TRUNCATED AT 250 WORDS)

Correlation of distribution of sulphonated aluminium phthalocyanines with their photodynamic effect in tumour and skin of mice bearing CaD2 mammary carcinoma

A chemical extraction assay and fluorescence microscopy incorporating a light-sensitive thermoelectrically cooled charge-coupled device (CCD) camera was used to study the kinetics of uptake, retention and localisation of disulphonated aluminium phthalocyanine (A1PcS2) and tetrasulphonated aluminium phthalocyanine (A1PcS4) at different time intervals after an i.p. injection at a dose of 10 mg kg-1 body weight (b.w.) in tumour and surrounding normal skin and muscle of female C3D2/F1 mice bearing CaD2 mammary carcinoma. Moreover, the photodynamic effect on the tumour and normal skin using sulphonated aluminium phthalocyanines (A1PcS1, A1PcS2, A1pcS4) and Photofrin was compared with respect to dye, dye dose and time interval between dye administration and light exposure. The maximal concentrations of A1PcS2 in the tumour tissue were reached 2-24 h after injection of the dye, while the amounts of A1PcS4 peaked 1-2 h after the dye administration. A1PcS2 was simultaneously localised in the interstitium and in the neoplastic cells of the tumour, whereas A1PcS4 appeared to localise only in the stroma of the tumour. The photodynamic efficiency (light was applied 24 h after dye injection at a dose of 10 mg kg-1 b.w.) of the tumours was found to decrease in the following order: A1PcS2 > A1PcS4 > Photofrin > A1PcS1. Furthermore, photodynamic efficacy was strongly dependent upon dye doses and time intervals between dye administration and light exposure: the higher the dose, the higher the photodynamic efficiency. The most efficient photodynamic therapy (PDT) of the tumour was reached (day 20 tumour-free) when light exposure took place 2 h after injection of A1PcS2 (10 mg kg-1). A dual intratumoral localisation pattern of the dye, as found for A1PcS2, seems desirable to obtain a high photodynamic efficiency. The kinetic patterns of uptake, retention and localisation of A1PcS2 and A1PcS4 are roughly correlated with their photodynamic effect on the tumour and normal skin.

Uptake, localization, and photodynamic effect of meso-tetra(hydroxyphenyl)porphine and its corresponding chlorin in normal and tumor tissues of mice bearing mammary carcinoma

By using a chemical extraction assay and confocal laser scanning fluorescence microscopy, the kinetic patterns of uptake, elimination, and localization of meso-tetra(hydroxyphenyl)porphine (m-THPP) and its corresponding chlorin (m-THPC) in tumors and various normal tissues of female C3D2/F1 mice bearing CaD2 mammary carcinoma were studied after an i.p. injection of either 5 mg/kg body weight of m-THPP or 1 mg/kg body weight of m-THPC. Moreover, the histological and ultrastructural alterations of the tumors were evaluated after photodynamic therapy (PDT) with m-THPP or m-THPC. The PDT efficacy with m-THPP and m-THPC was also compared. Both m-THPP and m-THPC had a similar kinetic pattern of distribution in the tumors and most normal tissues examined. The concentrations of the dyes in the tissues peaked at 24-48 h after injection. The peak values of the uptake of m-THPP by the tissues were found to decrease in the following order: spleen > urinary tract > kidney > liver > lung > tumor > heart > skin > muscle > brain. However, higher concentrations of m-THPC were taken up by the tumors than by most of the normal tissues studied except for the liver, urinary tract, and skin. m-THPP was mainly localized in the stroma of the tumors, whereas m-THPC was distributed in both vascular interstitium and neoplastic cells of the tumors. Morphological studies showed that PDT with m-THPP resulted in destructive changes in the microvasculature of the tumors, whereas m-THPC-based PDT destroyed both vascular walls and tumor cells of the tumors. The m-THPP-PDT of the tumors was much less efficient than m-THPC-PDT of the tumors, although the dose of m-THPP used was five times higher than that of m-THPC. m-THPP and m-THPC have different efficiency of sensitizing tumors to photodestruction, although they are similar with respect to hydrophobicity. This is likely due to the differences in their intratumoral localization patterns and in their absorption spectra.

The haem b558 component of the cytochrome bd quinol oxidase complex from Escherichia coli has histidine-methionine axial ligation

The cytochrome bd ubiquinol oxidase from Escherichia coli is induced when the bacteria are cultured under microaerophilic or low-aeration conditions. This membrane-bound respiratory oxidase catalyses the two-electron oxidation of ubiquinol and the four-electron reduction of dioxygen to water. The oxidase contains three haem prosthetic groups: haem b558, haem b595 and haem d. Haem d is the oxygen binding site, and it is likely that haem d and b595 form a bimetallic site in the enzyme. Haem b558 has been previously characterized spectroscopically as being low spin and has been shown to be located within subunit I (CydA) of this two-subunit enzyme. It is likely that haem b558 is associated with the quinol oxidation site, which has also been shown to be within subunit I. In a previous effort to locate the specific amino acids axially ligated to haem b558, all six histidines within subunit I were altered by site-directed mutagenesis. Only one, histidine-186, was identified as a likely ligand to haem b558. Hence it was suggested that haem b558 could not have bis(histidine) ligation. In the current work, a combination of low-temperature near-infrared magnetic circular dichroism (NIR-MCD) and EPR spectroscopies have been employed to identify the nature of the haem b558 axial ligands. The NIR-MCD spectrum at cryogenic temperatures is dominated by the low-spin haem b558 component of the complex, and the low-energy band near 1800 nm is strong evidence for histidine-methionine ligation. It is concluded that haem b558 is ligated to histidine-186 plus one of the methionines located within subunit I of the oxidase.

Influenza A virus RNA polymerase subunit PB2 is the endonuclease which cleaves host cell mRNA and functions only as the trimeric enzyme

The influenza A virus RNA-dependent RNA polymerase catalyzes several reactions in transcription and replication of the genome RNA. The first step in viral mRNA synthesis is the endonucleolytic cleavage of host cell mRNAs containing a cap structure to generate capped primers that are 10-14 nucleotides long which are then used to prime transcription of virus-specific mRNAs. To analyze the properties of the capped RNA-specific endonuclease associated with the influenza virus polymerase and the roles of each of the three subunits in transcription initiation, we established an in vitro assay to investigate this endonucleolytic cleavage reaction. This assay consists of an artificial RNA substrate containing a cap-0 structure at its 5' end and a partial alfalfa mosaic virus RNA 4 (AIMV RNA 4) sequence which had been shown to be cleaved by the influenza polymerase. Results showed that purified virion ribonucleoprotein complexes cleaved the RNA substrate specifically to generate a capped 14-nt RNA fragment for use as primer to initiate viral mRNA synthesis. Purified polyclonal anti-PB2 IgG inhibited the endonuclease activity, but anti-PB1 and anti-PA antibodies did not inhibit the cleavage. Partially purified trimeric polymerase expressed by recombinant baculovirus in insect cells cleaved the artificial substrate, but if one or two subunits were removed from the polymerase complex, the cleavage activity was totally lost. Our results suggest that viral PB2 protein is the endonuclease that cleaves host cell mRNA to produce the primer used to initiate transcription; however, association with the other two enzyme subunits seems to be required for this PB2 function.

The use of near-infrared charge-transfer transitions of low-spin ferric chlorins in axial ligand assignment

The near-infrared magnetic circular dichroism spectra of some low-spin derivatives of ferric-octaethylchlorin substituted myoglobin have been recorded at cryogenic temperatures. The spectra, which include some of the lowest energy charge-transfer transitions ever observed for hemes, are clearly dependent upon the nature of the axial ligands present. While the results indicate that such spectra may have some practical utility in axial ligand assignment, as is now quite common practice for iron-porphyrin systems, there are some severe practical limitations to this protocol documented in the case of iron-chlorins.

Pressure against the tumor can reduce the efficiency of photochemotherapy

C3D2/F1 mice with mammary carcinoma tumors growing subcutaneously on their right foot were given 10 mg/kg aluminium phthalocyanine tetrasulfonate (AlPcS4) by intraperitoneal injection. Twenty-four hours later these tumors were exposed to light at 680 nm. The size of the tumors was measured daily. An exposure of 135 J/cm2 (150 mW/cm2) reduced the tumor growth rate so that the time needed for the tumors to reach a volume five times larger than that at the time of exposure increased from 4 days for control tumors to 15 days. However, when a glass plate was gently pressed against the tumor surface during irradiation, the effect of an identical exposure was significantly smaller. In agreement with this, microscopic studies showed that tumors exposed to laser light without any pressure applied during irradiation were more damaged than tumors receiving a slight pressure. Thus, pressure against the tumor can obviously reduce the oxygen concentration in this tumor enough to reduce the efficiency of the treatment.

Immunoglobulin synthesis and generalized autoimmunity in mice congenitally deficient in alpha beta(+) T cells

Through cognate B-cell-T-cell interactions and provision of cytokines, CD4+ T-cell antigen receptor (TCR) alpha beta+ T cells regulate immunoglobulin isotype synthesis. Murine IgG1 and IgE secretion is therefore substantially T-cell-dependent, whereas IgM and IgG3 secretion is not. Here we report that in the absence of alpha beta T cells, B cells expand, differentiate and secrete copious amounts of antibodies of 'T-dependent' isotypes. Moreover, the antibodies are reactive towards self-antigens, as in patients with systemic lupus erythematosus, so autoantibodies of 'T-dependent' type can develop without the help of CD4+ alpha beta T cells. This phenotype is not evident in mice or humans that are congenitally deficient in specific alpha beta T-cell functions, but bears comparison with B-cell hyperactivity and autoimmunity in transplant rejection and in immunodeficiencies such as AIDS.

Identification of axial ligands of cytochrome c552 from Nitrosomonas europaea

Cytochrome c552 from Nitrosomonas europaea was analyzed by visible, EPR and MCD spectroscopies. The visible and MCD data show that histidine and methionine are the axial ligands to the heme iron of the ferric protein. The EPR spectrum of the cytochrome shows an atypical highly axial low spin (HALS) type signal with g-values that make it difficult to identify the axial ligands. These results reinforce the value of near-infrared MCD spectroscopy for assigning ligands in ferric heme systems and point out the difficulties in using only EPR spectroscopy for the same purpose. The description of another c-cytochrome exhibiting a HALS-type EPR signal will eventually be helpful in explaining the physical basis for this unusual signal.

Anticomplement activity in human aqueous humor

Twenty-six samples of human aqueous humor from patients with cataract and glaucoma were analyzed on anticomplement activity. The mean inhibitory rate was 15.32 +/- 14.60%, ranging from 0.93 to 60.02%. The inhibitory effect appeared in a dose-dependent manner. No significant differences were found between males and females (p > 0.05) and between samples of different age (p > 0.05). We revealed that aqueous humor had an inhibitory effect on complement activity. This indicates that human aqueous humor has an immune regulatory function.

Uptake and distribution of intravenously or intravesically administered photosensitizers in the rat

Photodynamic therapy using i.v. injected porphyrin photosensitizers have been used to treat selected cases of superficial bladder cancer. Since cutaneous photosensitivity, lasting 6-8 weeks, is a well known undesirable side effect of this therapy, we instilled the photosensitizers intravesically in rats and compared the uptake of photosensitizers in different tissues by this route of administration with the uptake after intravenous injection. The intravesical mode of delivery enhanced photosensitizer uptake in the bladder wall, while giving low concentrations in extravesical organs. Intravesical instillation of the photosensitizers may therefore increase their efficacy and reduce phototoxicity as compared with intravenous injection. Comparing the results obtained by two assays, one based on porphyrin fluorescence and the other based on the application of radioactively labelled photosensitizers, it was concluded that the i.v. administration route may result in tissue uptake of significant amounts of aggregated non-fluorescent, supposedly inactive drug, while the intravesical administration led to less uptake of aggregates relative to active drug monomers.

Tissue carriers for processing fragile bio-materials in immuno-electron microscopy

The preparation and use of tissue carriers for processing fragile biological materials from postfixation up to embedding in electron microscopy is described. Trimmed small pieces of vibratome sections can be very practical and safely transported in these carriers throughout osmification, dehydration for long times, and infiltration up to embedding in epoxy resins. This small device is especially suited for post-embedding immunogold electron microscopy.

Biodistribution of a methylene blue derivative in tumor and normal tissues of rats

By using a chemical extraction procedure and confocal laser scanning fluorescence microscopy we have investigated the kinetic patterns of uptake and biolocalization of a methylene blue derivative (MBD) in tumors and various normal tissues of Wistar rats bearing fibrosarcoma (Leeds ovarian tumor) after intravenous injection of MBD (10 mg kg-1 body weight). Similar kinetics of accumulation and elimination of MBD fluorescence were found in tumor tissue and surrounding normal skin and muscle tissues. However, the tumor:skin and tumor:muscle ratios of the MBD fluorescence intensity were found to be 9 and 4, respectively, 4 h after intravenous injection, indicating selective uptake of MBD by the tumor tissue. MBD was localized on the walls of all the vessels and extensively in the area of neoplastic cellular and tumorigenic fibrous components in the tumor tissue. Interestingly, no MBD fluorescence could be detected in the metastatic neoplastic cells in the remote lymph nodes. In the skin, MBD was mainly distributed in the keratinized epithelium of the epidermis, hair follicles and their accessories, while little was found both in the epidermis and dermis. In most other tissues, the maximal fluorescence intensity of MBD was found 1-4 h after injection, after which it decreased dramatically to almost undetectable levels 120 h postinjection. Strong fluorescence of MBD was seen in the tracheal mucosal epithelium, while little fluorescence was noted in the transitional epithelium of bladder. The kinetics of biolocalization of MBD in some other tissues (liver, spleen, kidney, brain, muscle, lung, heart) were also studied.

A new technique for post-embedding immunogold localization of vasopressin in the rat median eminence

A modified cryosubstitution method is described which simultaneously preserves the ultrastructure and antigenicity of the osmium-sensitive neuropeptide vasopressin in rat median eminences. The organs were aldehyde-fixed, osmicated, and embedded in Epon. Thin sections were no longer needed to be etched and the titer of primary antiserum was near to the light microscopic level. Furthermore ice crystallization could not be observed.

Potentiation of photodynamic therapy by mitomycin C in cultured human colon adenocarcinoma cells

The effects of photodynamic therapy (PDT) alone and in combination with Mitomycin C (MMC) on WiDr cells, a human colon adenocarcinoma cell line, were investigated. The addition of MMC increased the cytotoxicity of PDT. The presence of MMC resulted in a reduction or a removal of the shoulder of the PDT survival curves as well as an increase in their slopes. Increasing with the concentrations of MMC from 0.01 to 0.025 micrograms/ml, the cytotoxic effects of the two treatments changed from additivity to supra-additivity as judged by comparing dose-response curves for each treatment alone with survival curves after combination therapy and by isobologram analysis. The cytotoxicity of MMC could also be enhanced by a practically nontoxic treatment of PDT (8% cell inactivation). The cytotoxicities of MMC and PDT in combination were found to be dependent on the sequence of the two treatments. When MMC (> or = 0.02 micrograms/ml) and Photofrin II were given simultaneously for 16 h and then followed by irradiation, the combination was found to be more effective than when MMC was given to the cells immediately after PDT and kept in the medium for 16 h. Possible mechanisms of the combination effects of PDT and MMC are discussed briefly.

Incubation chambers for the staining of ultrathin sections. An in situ technique especially suited for immunocytochemistry

The preparation and use of incubation chambers for staining of ultrathin sections is described. As an example the immunogold staining is given which can be carried out in these devices in a more simple manner than normally possible, and with good results as shown by electron microscopy.

[Effects of prostaglandin E2 on growth and function of osteoblasts in human cell culture in vitro]

The effects of prostaglandin E 2 (PGE2) on the differentiation and proliferation of osteoblasts (human fetal bone-cells) cultured in serum-free medium were investigated by assays of alkaline phosphatase (ALP) activity, intracellular cyclic AMP level and collagen synthesis in the cells. The results suggested that PGE2 in physiologic concentration stimulated the differentiation of osteoblasts in vitro, and might be involved in bone formation in vivo.

Cytotoxicity and cytokinetic effects of mitomycin C and/or photochemotherapy in a human colon adenocarcinoma cell line

1. The cytotoxicity and cytokinetic effects of Mitomycin C (MC) and/or photochemotherapy (PCT) in cultured human colon adenocarcinoma (WiDr) cells were investigated using colony formation to determine cell survival and DNA flow cytometry to analyze cell kinetics. 2. A low concentration of MC (0.01 micrograms/ml) caused accumulation of cells in late S and early G2 phase; higher concentrations (0.05-0.5 micrograms/ml) induced accumulation of the cells in mid and early S phase. 3. The effects of the lowest concentration of MC (0.01 micrograms/ml) were reversible upon removal of the drug, whereas a higher concentration of MC (0.1 micrograms/ml) resulted in a permanent inhibition of cell cycle progression. 4. The sensitivity of Photofrin II-loaded cells to PCT can be enhanced significantly by the addition of MC. 5. The MC-induced accumulation of the cells in S phase may be one reason for the increased cytotoxicity of PCT combined with MC. 6. The data suggest that MC may also inhibit repair of PCT-induced DNA damage.

Distribution and photosensitizing efficiency of porphyrins induced by application of exogenous 5-aminolevulinic acid in mice bearing mammary carcinoma

By means of a chemical extraction procedure and confocal laser scanning microscopy, we investigated the kinetic patterns of uptake and biolocalization of 5-aminolevulinic acid (ALA)-induced porphyrins in s.c. transplanted tumors, adjacent normal skin and muscle, and liver of mice bearing mammary carcinoma, after i.p. injection of 250 mg/kg ALA or topical application of ALA (20% in an oil-in-water emulsion). Furthermore, we evaluated the tumor responses after either i.p. injection or topical application of 5-ALA followed by laser irradiation (632 nm, 150 mW/cm2, 25 min) by measuring the treated tumor regression/regrowth time and by light and electron microscopy. Strong fluorescence of ALA-induced porphyrins was detected in the tumor, skin and liver tissues, while little fluorescence was seen in the adjacent muscle tissue. Moreover, the highest amounts of ALA-induced porphyrins in the tumor and skin tissues were found 1 hr after i.p. injection, whereas the amounts of the porphyrins in both tissues increased with increasing time after topical application of ALA. The fluorescence of the porphyrins was localized in several components of the skin tissue (epidermis, hair follicles and their associated sebaceous glands). Furthermore, the fluorescence was diffusely distributed in the s.c. transplanted tumor tissue. Little could be observed under a confocal laser scan microscope (CLSM) in the muscle tissue. The uptake and biolocalization data correlate well with the results of PCT efficiency of the same tumor model with ALA-induced porphyrins. Light and electron microscopy showed that the mitochondria of the tumor cells and of the endothelial cells and the basal lamina of vascular walls beneath the endothelium in the tumor tissue were initially extensively destroyed after PCT with ALA-induced porphyrins. Thereafter, diffuse degeneration followed by local and/or diffuse severe necrosis of the tumor cells was found. This may be due mainly to the initial damage to mitochondria in the cancerous and endothelial cells and also to the destruction of the vascular wall in the tumor tissue.

Identification of heme macrocycle type by near-infrared magnetic circular dichroism spectroscopy at cryogenic temperatures

The electron paramagnetic resonance (EPR) and near-infrared magnetic circular dichroism (MCD) spectra of the azide and cyanide adducts of nitrimyoglobin and hydroperoxidase II from Escherichia coli have been measured at cryogenic temperatures. For the first time, ligand-to-metal charge-transfer transitions in the near-infrared have been observed for an Fe(III)-chlorine system. It is shown that near-ultraviolet-to-visible region electronic spectra of 'green' hemes such as these are an unreliable indicator of macrocycle type. However, the combined application of EPR and near-infrared MCD spectroscopies clearly distinguishes between the porphyrin-containing nitrimyoglobin and the chlorine-containing hydroperoxidase II.

Effects of light exposure on the uptake of photofrin II in tumors and normal tissues

DBA mice bearing CaD2 mammary carcinomas were used to determine the effect of giving small doses of light to the tumor area 1.5 hr after injecting Photofrin II (PII). The smallest light dose applied (12.5 J/cm2) had no effect on the uptake of PII in the tumor and its surrounding tissues, as measured 24 hr after the i.p. injection. However, several higher light doses increased the uptake of PII in the tumor significantly, the uptake in skin slightly, while the uptake in muscle tissue was decreased rather than increased. Thus, the PII concentration ratio between the tumor and the surrounding normal tissues was significantly improved. The rates of clearance of PII from irradiated tissues and non-irradiated tissues were not significantly different. Most likely, the present observations are due to transient pH lowering in the tumor resulting from vascular damage.

Effect of mitomycin C on the uptake of photofrin II in a human colon adenocarcinoma cell line

Flow cytometry (FCM) was used to investigate the effect of mitomycin C (MC) on the cellular uptake of Photofrin II (PII) in a cultured human colon adenocarcinoma cell line (WiDr). The surface area of the cells increased as they passed through the cell cycle from G0/G1 to G2/M phase. MC retarded the cells in G2/M phase and enhanced the surface area of the cells. A 1.3-2.3-fold increase in the cell surface area and a 1.3-2.7-fold increase in the cellular uptake of PII in the tumor cells was observed after 2 h-8 h incubation with MC. Within each sample, an almost linear relationship between the intensity of PII fluorescence in the cells and the surface area of the cells was found. However, for the cells incubated with MC the surface area was not the only determinant of PII uptake. Effects of MC on the cell cycle, the cell surface area and the permeability of the cell membrane are suggested as possible reasons for the increase of cellular uptake of PII in the tumor cells.