Protein kinase C inhibitors induce apoptosis in human malignant glioma cell lines

Previous work has demonstrated the importance of the protein kinase C (PKC) system in regulating glioma growth, and has led to clinical trials utilizing PKC inhibitors as adjuncts in the therapy of patients harboring malignant gliomas. This study was performed to explore the possibility that inhibition of PKC in gliomas was triggering an apoptosis signal. Glioma cell lines were treated with PKC inhibitors staurosporine (10 nM), and tamoxifen (10 microM). DNA from cells treated with each of these drugs exhibited a 'ladder' pattern of oligonucleosome-sized fragments characteristic of apoptosis, thus suggesting that in glioma cells, these drugs may be cytocidal in action.

Dexamethasone induced proliferation of cultured retinal pigment epithelial cells

Dexamethasone (DEX) is a glucocorticoid that is widely used after vitreoretinal surgery and may have mitogenic properties. This study was initiated to determine if human cultured retinal pigment epithelium (RPE) cells express glucocorticoid receptor and proliferate in response to DEX stimulation. Glucocorticoid receptor mRNA was detected in RPE cells by means of reverse transcriptase polymerase chain reaction. To determine the effect of DEX on RPE cell proliferation in vitro, we cultured human RPE cells with various concentrations for DEX for 5 days and determined the effects on cell number and incorporation of tritiated thymidine. DEX treatment with a DEX dose of 1 microgram/ml in the presence or absence of serum resulted in a maximal 2-3 times increase in cell number. Autoradiography after thymidine incorporation revealed a greater than 2-fold increase in incorporating cells at this same dose. These results indicate that DEX causes cultured human RPE cells to proliferate and suggest that it may have a growth factor-like action.

Transplantation of cultured human retinal pigment epithelium into rabbit subretina

Transplantation of normal retinal pigment epithelium (RPE) into a diseased eye holds promise for treatment of several blinding disorders. Previous studies have involved immunosuppression and implantation of freshly isolated cells. We report here the successful transplantation of cultured human RPE cells into rabbits that were not immunosuppressed. A modified pars plana transvitreal technique was used for RPE transplantation. The cultured RPE cells, loaded with carbon as a marker, were transplanted into the denuded Bruch's membrane of albino rabbits. The animals were followed for from 1 week to 3 months. On histologic examination at 2 months, no infiltrating lymphocytes were found in the vitreous cavity or choroid, even though Bruch's membrane was damaged. At about 3 months there were some macrophages in the subretina of transplanted eyes, indicating that an immunoreaction does occur eventually. Electron microscopy of the transplanted RPE showed apical-basal polarity and gap junctions. Restored function was attested to by the presence of phagosomes and phagocytosed outer segments in the transplanted cells. Our findings suggest that there is a weak, delayed immunoreaction to human RPE cells transplanted beneath the retina of the rabbit; however, functional recovery of the transplanted cells occurs before this immune response develops.

IL-6 down-modulates the cytokine-enhanced antileishmanial activity in human macrophages

IL-6 is a cytokine synthesized by T cells and macrophages (M phi). It has pleiotropic effects on diverse cell types and is recognized for its "pro-inflammatory" properties. In mice, IL-4, IL-5, IL-6, and IL-10 are produced by Th-2 cells. Because IL-10 suppresses Th-1 clones, and IL-4 broadly deactivates M phi, experiments were carried out to investigate the in vitro effects of recombinant human IL-6 on cytokine activation of human M phi. Pretreatment with IL-6 induced a dose- and time-dependent suppression of IFN-gamma (1000 U/mL) and TNF-alpha (25 ng/mL) activation of M phi for the killing of L. amazonensis. At doses greater than 0.1 to 100 ng/mL, IL-6 inhibited IFN-gamma and TNF-alpha activation by 21 to 93% and 36 to 82%, respectively. IL-6 alone had no effect on M phi viability and intracellular L. amazonensis growth. Blockade of M phi activation was greatest when IL-6 was added 24 or 48 h before infection and treatment with IFN-gamma or TNF-alpha. Furthermore, mAb against IL-6 abrogated the inhibitory activity of IL-6. Similarly IL-6 pretreatment suppressed M phi activation for antileishmanial capacity by IL-3, granulocyte-monocyte-CSF (GM-CSF) and IL-1 beta. Because cytokine induction of antileishmanial activity is associated with enhancement of oxidative capacity, the effect of IL-6 on this mechanism was evaluated. Pretreatment with IL-6 down-modulated TNF-alpha (25 ng/mL) enhancement of M phi oxidative capacity in a dose- and time-dependent manner. A similar depression of oxidative capacity was observed for GM-CSF and IL-3 but not for IFN-gamma. Furthermore, NG-monomethyl-L-arginine (a nitric oxide synthase inhibitor) had no effect on IFN-gamma and TNF-alpha activation of antileishmanial activity and nitrites/nitrates were not reliably assayed from M phi culture supernatants. These findings suggest that IL-6 down-modulates cytokine activation of M phi antileishmanial capacity by inhibiting oxygen-dependent and undefined oxygen-independent mechanisms.

Retrospective study comparing the pathophysiology of antibiotic-treated and untreated Escherichia coli- and Staphylococcus aureus-infused baboons

Escherichia coli and Staphylococcus aureus are the most common pathogens encountered in septic shock. This is a descriptive study in which the pathophysiologic response to infusions of LD100 concentrations of E. coli and S. aureus are staged and compared. Equivalent concentrations of both organisms were infused over a 2 hr period into antibiotic-treated and untreated animals with the following results: 1) The apparent clearance of E. coli was less than that of S. aureus over the 2-hr infusion period, but far greater during the next 8 hr in both antibiotic-treated and untreated animals. Thus the clearance of E. coli fits a one-compartment (intravascular), and that of S. aureus fits a two-compartment (intra- and extravascular) model. 2) The intensity of the cardiovascular, temperature, and metabolic response to E. coli was greater, whereas that of the disseminated intravascular coagulant (DIC) response to S. aureus was greater. We conclude, therefore, that the response to E. coli consists of four stages with no invasion and colonization of tissues, whereas the response to S. aureus consists of two stages with invasion and colonization of tissues.

IL-6 down-modulates the cytokine-enhanced antileishmanial activity in human macrophages

IL-6 is a cytokine synthesized by T cells and macrophages (M phi). It has pleiotropic effects on diverse cell types and is recognized for its "pro-inflammatory" properties. In mice, IL-4, IL-5, IL-6, and IL-10 are produced by Th-2 cells. Because IL-10 suppresses Th-1 clones, and IL-4 broadly deactivates M phi, experiments were carried out to investigate the in vitro effects of recombinant human IL-6 on cytokine activation of human M phi. Pretreatment with IL-6 induced a dose- and time-dependent suppression of IFN-gamma (1000 U/mL) and TNF-alpha (25 ng/mL) activation of M phi for the killing of L. amazonensis. At doses greater than 0.1 to 100 ng/mL, IL-6 inhibited IFN-gamma and TNF-alpha activation by 21 to 93% and 36 to 82%, respectively. IL-6 alone had no effect on M phi viability and intracellular L. amazonensis growth. Blockade of M phi activation was greatest when IL-6 was added 24 or 48 h before infection and treatment with IFN-gamma or TNF-alpha. Furthermore, mAb against IL-6 abrogated the inhibitory activity of IL-6. Similarly IL-6 pretreatment suppressed M phi activation for antileishmanial capacity by IL-3, granulocyte-monocyte-CSF (GM-CSF) and IL-1 beta. Because cytokine induction of antileishmanial activity is associated with enhancement of oxidative capacity, the effect of IL-6 on this mechanism was evaluated. Pretreatment with IL-6 down-modulated TNF-alpha (25 ng/mL) enhancement of M phi oxidative capacity in a dose- and time-dependent manner. A similar depression of oxidative capacity was observed for GM-CSF and IL-3 but not for IFN-gamma. Furthermore, NG-monomethyl-L-arginine (a nitric oxide synthase inhibitor) had no effect on IFN-gamma and TNF-alpha activation of antileishmanial activity and nitrites/nitrates were not reliably assayed from M phi culture supernatants. These findings suggest that IL-6 down-modulates cytokine activation of M phi antileishmanial capacity by inhibiting oxygen-dependent and undefined oxygen-independent mechanisms.

Visible flicker from invisible patterns

Using a laser interferometer we can create grating patterns of high optical contrast (interference fringes) directly on the retina. With coarse fringe patterns, the alternating light and dark bars of the pattern can be seen, but the bars of the finest fringes are not subjectively resolved. We report here that when we rapidly modulate the contrast of a fine fringe pattern (keeping overall luminance constant), observers experience flicker, even if the fringes are too finely spaced to be perceived as a grating. For this flicker to be seen, the pattern needs to be resolvable by the photoreceptors themselves, but not necessarily by later stages of visual processing. It can be explained if, in man, signals associated with individual cone receptors do not depend linearly on light intensity, but instead are scaled by a fast sensitivity-regulating or light-adaptation mechanism. Contrast-modulation flicker is not demonstrable in rod vision; rod vision therefore lacks such a local adaptation process.

Cytogenetic damage and tumor incidence in mouse skin after single, topical applications of 7,12-dimethylbenz[a]anthracene

Micronucleus induction, chromosomal damage and aneuploidy were evaluated in whole skin keratinocyte cultures derived from HRA/Skh mice after single in vivo applications of 0.256, 2.56 and 25.6 micrograms (1, 10 and 100 nmoles) of the carcinogen, 7,12-dimethylbenz[a]anthracene (DMBA). These genotoxicity end-points were compared with papilloma and carcinoma occurrence at the same dose levels of carcinogen. While the lower 2 doses of DMBA significantly increased the incidence of micronuclei and other chromosomal anomalies in keratinocytes, the two highest doses resulted in a significantly increased papilloma yield (0.297 and 3.895 papillomas/mouse) and incidence (24.3 and 100%). Carcinomas appeared only at the highest dose (0.125 carcinomas/mouse; 5% incidence). Neither papillomas nor carcinomas occurred in solvent-treated control mice. None of the three applied doses induced aneuploidy under conditions leading to an increase in tumors and/or chromosomal damage.

Detection of DNA sequence polymorphisms among wheat varieties

A DNA marker detection strategy that allows the rapid, efficient resolution of high levels of polymorphism among closely related lines of common wheat (Triticum aestivum) has been developed to circumvent the apparent lack of restriction fragment length polymorphism in many important self-pollinated crop species. The technique of randomly amplified polymorphic DNA (RAPD) was combined with a denaturing gradient gel electrophoresis system (DGGE) to explore DNA sequence polymorphisms among different genotypes of wheat. Of the 65 primer combinations used for the polymerase chain reaction (PCR) amplifications, over 38% of them produced readily detectable and reproducible DNA polymorphisms between a spring wheat line, SO852, and a winter wheat variety, 'Clark'. A high level of polymorphism was observed among a number of commercial varieties and breeding lines of wheat. This procedure was also used to detect polymorphisms in a recombinant inbred population to test the feasibility of its application in genome mapping. This DNA polymorphism detection system provides an opportunity for pedigree analysis and fingerprinting of developed wheat lines as well as construction of a high density genetic map of wheat. Without the need for (32)P and sophisticated DNA extraction procedures, this approach should make it feasible to utilize marker-based selection in a plant breeding program.

[Hepatic segmentectomy using microwave tissue coagulator]

Hepatic segmentectomy using a microwave tissue coagulator guided by intraoperative ultrasonography is a new operative procedure, which our research unit was the first to start using from 1990. Up to now we have performed this kind of operation with success in 26 cases. Our results suggested that the new procedure simplified the original operation and greatly reduced the risk of hemorrhage and iatrogenic spread of the cancer cells during operation. Besides, this operation as a kind of definite anatomic hepatectomy can minimally resect the tumor bearing tissue in a radical fashion, while maximally preserve the tumor-free tissue of the liver.

Use of radiation with or without WR-2721 in advanced rectal cancer

One hundred patients with inoperable, unresectable, or recurrent adenocarcinoma of the rectum were stratified and randomized to WR-2721 plus radiation therapy (WR + RT) or radiation therapy (RT) only treatment arms. The protector, WR-2721, was administered at a dose of 340 mg/m2 15 minutes before RT, 4 days a week for 5 weeks. The entire pelvis received 225 cGy per fraction for a total of 4500 cGy. The RT only group received the same treatment schedule. After this, both groups received a conedown of 720 cGy in 4 fractions. Inoperable and unresectable cases received a second conedown of 720 cGy. No moderate or severe pelvic normal tissue late effects were seen in the 34 evaluable patients in the combination group. However, in the RT only group, 5 of 37 evaluable patients exhibited late effects of moderate or severe degree. This difference was statistically significant (P = 0.03). There was no evidence of tumor protection by WR-2721. Sixteen percent of patients randomized to the WR + RT group had a complete response compared with 10% in the RT only group. The conditions of 12 patients of 100 became operable and 8 were resected. Seven of these patients remain free of recurrence.

Antibody drug carrier for immunotherapy of superficial bladder cancer: ultrastructural studies

Superficial bladder cancer represents a promising target for intravesical, antibody-guided therapy. The construction of an optimum antibody-cytotoxic drug conjugate depends mostly on the appropriate selection of a monoclonal antibody (mAb). We have used immunogold labeling and SEM to specifically map the distribution of antigens expressed on three bladder cancer cell lines and on the luminal surface of biopsies from human transitional cell carcinoma of various grades and from normal bladder mucosa. The 48-127 mAb, which recognizes a M(r) 54,000 surface glycoprotein (gp54), was found to be very promising as a potential drug carrier. This antibody reacts with the surface of cells from low- and high-grade tumors; it does not react with the normal urothelium. Labeling of normal bladder mucosa was observed, however, on microvillous intermediate urothelial cells occasionally exposed by small areas of desquamation. The 48-127 mAb could target drugs to all areas of transformed urothelium while avoiding drug delivery to the normal, undesquamated bladder mucosa. Kinetics of gp54/48-127/gold complexes were tested in vitro with T24 and RT4 human bladder carcinoma cell lines incubated in the presence of the 48-127 mAb directly conjugated with 17.7-nm gold particles. Internalization of the gp54/48-127/gold complex was readily demonstrated by transmission electron microscopy. These results suggest that the 48-127 mAb represents a valuable drug carrier for intravesical therapy, allowing specific tumor targeting and internalization of various cytotoxic agents.

Tumorigenicity of cyclopenta[a]phenanthrene derivatives and micronucleus induction in mouse skin

The most potent carcinogen of the cyclopenta[a]phenanthrene series, 15, 16-dihydro-11-methylcyclopenta[a]phenanthren-17-one and its non-carcinogenic, unmethylated parent compound, were compared for their abilities to induce micronuclei in epidermal keratinocytes after application onto the dorsal skin of Skh/HR-1 hairless mice. Although both substances were shown to be mutagenic in vitro, only the 11-methyl derivative has been proven to initiate cancer in TO and Sencar mouse strains. In the present study, only the 11-methyl derivative was active as a cancer initiator in Skh/HR-1 mice. For studying micronucleus induction, a preliminary experiment was conducted to establish doses of both chemicals that allowed cell survival. Subsequently, micronucleus induction in epidermal keratinocytes was shown to agree with the cancer-initiating potential of the two compounds. Only the carcinogenic derivative induced a statistically significant increase in micronuclei, over the range 10-100 nmol. This is considerably lower than the dose of approximately 1600 nmol commonly used to initiate skin cancer in mice, but is comparable to the active dose range for skin micronucleus induction by benzo[a]pyrene, a chemical of equivalent carcinogenic potency.

Interim analysis of a randomized trial of radiation therapy of rectal cancer with/without WR-2721

The objectives of this randomized trial are to define the maximum tolerated dose of radiation therapy, at curative dose levels, that can be delivered following WR-2721, and to observe the anti-tumor effects and normal tissue responses. One hundred patients with inoperable, unresectable, or recurrent rectal cancer were stratified and randomized to radiation only, or WR-2721 and radiation. The entire pelvis is treated with 4 portals 4 times a week to a total of 4500 cGy (first level dose) in 5 weeks. WR-2721, 340 mg/m2 was given 15 minutes before radiation to the combination group. Subsequently, both groups received a conedown of 720 cGy in 4 days to 144(2) cm portals APPA, and if originally inoperable or unresectable 720 cGy in four days to second conedown of 64(2) cm. Patients were observed from 3 to 18 months (median = 12 months). No significant hypotension or hematologic toxicity occurred in the WR-2721 treated group. Mild to moderate emesis occurred in 80% of the courses. (No antiemetics were used.) Moderate or severe acute toxicities to normal tissues were observed less frequently in the WR-2721 arm. No moderate or severe late toxicities to the skin, mucous membrane, urinary bladder or intestine was observed in the WR-2721 group, however, 5 patients treated with radiation alone experienced moderate or severe late toxicity to these organs. No evidence of tumor protection was observed.