Enhanced eradication of local and distant tumors by genetically produced interleukin-12 and radiation

Ionizing radiation (IR) is frequently unsuccessful in the treatment of cancer because of local failure or distant metastases. The efficacy of systemically administered cytokines for cancer therapy is often limited by toxicity. We report that intratumoral injection of an adenoviral vector with interleukin-12 (IL-12) enhances local anti-tumor effects of irradiation (IR). We demonstrate that microscopic tumor growth at a distant site is suppressed following treatment of the primary tumor with adeno-murine IL-12 (Adm.IL-12). The results support a model in which the anti-angiogenic effects of IL-12 contribute to the local anti-tumor effects of radiation, while IL-12 induced immunity suppresses growth of microscopic tumors distant from the primary irradiated site. These data suggest that combining radiotherapy with IL-12 improves both local and distant tumor control compared to either treatment alone. Immunoradiotherapy may be employed in addition to or in place of current conventional therapies to increase local control and decrease distant tumor growth.

CD4(+) T cells eliminate MHC class II-negative cancer cells in vivo by indirect effects of IFN-gamma

CD4(+) T cells can eliminate tumor cells in vivo in the absence of CD8(+) T cells. We have CD4(+) T cells specific for a MHC class II-restricted, tumor-specific peptide derived from a mutant ribosomal protein expressed by the UV light-induced tumor 6132A-PRO. By using neutralizing mAb specific for murine IFN-gamma and adoptive transfer of CD4(+) T cells into severe combined immunodeficient mice, we show that anti-IFN-gamma treatment abolishes the CD4(+) T cell-mediated rejection of the tumor cells in vivo. The tumor cells were MHC class II negative, and IFN-gamma did not induce MHC class II expression in vitro. Therefore, the tumor-specific antigenic peptide must be presented by host cells and not the tumor cells. Tumor cells transduced to secrete IFN-gamma had a markedly reduced growth rate in severe combined immunodeficient mice, but IFN-gamma did not inhibit the growth of the tumor cells in vitro. Furthermore, tumor cells stably expressing a dominant-negative truncated form of the murine IFN-gamma receptor alpha chain, and therefore insensitive to IFN-gamma, nevertheless were rejected by the adoptively transferred CD4(+) T cells. Thus, host cells, and not tumor cells, seem to be the target of IFN-gamma. Together, these results show that CD4(+) T cells can eliminate IFN-gamma-insensitive, MHC class II-negative cancer cells by an indirect mechanism that depends on IFN-gamma.

X-ray structure and conformational dynamics of the HIV-1 protease in complex with the inhibitor SDZ283-910: agreement of time-resolved spectroscopy and molecular dynamics simulations

Based on the X-ray structure of the human immunodeficiency virus type-1 (HIV-1) protease in complex with the statine-derived inhibitor SDZ283-910, a 542 ps molecular dynamics trajectory was computed. For comparison with the 805 ps trajectory obtained for the uncomplexed enzyme, the theoretical fluorescence anisotropy decay of the unliganded protease and the inhibitor complex was calculated from the trajectories of the Trp6A/Trp6B and Trp42A/Trp42B transition dipole moments. This enabled us to directly compare the simulated data with the experimental picosecond time-resolved fluorescence data. Fitting both experimental and simulated data to the Kohlrausch-Williams-Watts (KWW) function exp(-t/tauk)beta revealed a very good agreement for the uncomplexed protease as well as for the SDZ283-910 complex. Binding of the inhibitor induced a faster decay of both the experimental and the computed protease fluorescence anisotropy decay. By this integrative approach, the atomic detail of inhibitor-induced changes in the conformational dynamics of the HIV-1 protease was experimentally verified and will be used for further inhibitor optimisation.

Central nervous system effects of intranasally administered insulin during euglycemia in men

Insulin receptors have been detected in several structures of the brain, yet the biological significance of insulin acting on the brain remains rather unclear. In humans, direct central nervous effects of insulin are difficult to distinguish from alterations in neuronal functions because of insulin-induced decrease in blood glucose levels. Since several intranasally administered viruses, peptides, and hormones have been shown to penetrate directly from the nose to the brain, we tested whether insulin after intranasal administration likewise has access to the brain. After a 60-min baseline period, insulin (20 IU H-Insulin 100 Hoechst) or vehicle (2.7 mg/ml m-Cresol) was intranasally administered every 15 min to 18 healthy subjects according to a double-blind within-subject crossover design. Auditory-evoked potentials (AEP) indexing cortical sensory processing were recorded while the subjects performed a vigilance task (oddball paradigm) during the baseline phase and after 60 min of intranasal treatment with insulin or placebo. Blood glucose and serum insulin levels were not affected by intranasal insulin. Compared with placebo, intranasal administration of insulin reduced amplitudes of the N1 (P < 0.005) and P3 (P < 0.02) components of the AEP and increased P3 latency (P < 0.05). The reduction in P3 amplitude was most pronounced over the frontal recording site (2.42 +/- 1.00 vs. 4.92 +/- 0.79 microV, P < 0.0005). At this site, after insulin administration, a broad negative shift developed in the AEP between 280 and 500 ms poststimulus (area under the curve -166.0 +/- 183.8 vs. 270.8 +/- 138.7 microV x ms after placebo, P < 0.01). The results suggest that after intranasal administration, insulin directly enters the brain and exerts distinct influences on central nervous functions in humans.

Active immunization against cancer cells: impediments and advances

Immunotherapy of cancer is still mainly an experimental treatment. Some monoclonal antibodies have been approved for adjuvant therapy of cancer in patients, but active immunization strategies have not yet matured to this stage. The fact that vaccination against viral diseases is effective has primed high expectations for successful vaccination against cancer as well. Indeed, in some animal models, therapeutic results could be obtained against short-term established tumors, which paved the way for clinical trials. However, the first results with active immunization in cancer patients were disappointing and this led to a careful examination of current protocols and the search for more effective approaches. Evaluation of the available data suggests that cancer patients may not be comparable in their immune response to cancer vaccines with healthy persons. Furthermore, the tumor seems to be able to develop several immune-escape mechanisms, which either inactivate the specific immune cells or prevent activation of potential effector mechanisms against the tumor. Here, we review the impediments that have been identified in murine models and clinical trials for immunotherapy of cancer. It will be important to study the hurdles to come to a better understanding of the immune evasion of tumors and to achieve efficient activation of the immune system in cancer patients against the tumor. This knowledge will open new possibilities for active immunization against cancer.

Loss of resistance to a highly immunogenic tumor with age corresponds to the decline of CD8 T cell activity

A number of ultraviolet light-induced tumors that do not grow progressively in 3- or 9-month-old animals grow progressively in animals starting at approximately 15 months of age. We investigated the immune response to one such tumor, 6130, in young and old mice to determine in nature of this breakdown in immune protection with age. The 6130 tumor cells that grow progressively in 22-month-old animals still retain sensitivity of cytotoxic T lymphocytes (CTLs) generated against the highly immunogenic "6130-A" antigen and consequently are still immunologically rejected when transplanted into 3- and 9-month-old animals, but not in mice older than 15 months. Investigation of the CD8+ CTL response found that in animals 3-12 months old, primary and secondary tumor-specific CTL responses to 6130 can be generated in vivo and in vitro. On the other hand, the CD8+ CTL responses to 6130 seen in animals 15 months of age or older were significantly depressed or absent. These results indicate that a decline in antigen-specific CD8+ CTL is the major cause of increased susceptibility to 6130 tumor growth in older animals.

Tumor cells induce cytolytic T cells to a single immunodominant mutant peptide

Two different approaches have shown that cancers express mutant proteins that may be recognized as tumor-specific antigens. On the one hand, DNA sequences known to be mutant in tumor cells have been used to select for mutant peptides that induce tumor-specific T cells (the so-called "reverse immunologic" approach). On the other, T cells induced by vaccination with whole tumor cells have been used to identify tumor-specific mutations in proteins ("direct immunologic approach"). While both approaches generate tumor-specific T cells that can lyse cancer cells expressing the relevant mutant protein, the present study suggests that there may be crucial differences. Mutant epitopes originally defined from DNA sequences have so far been immunorecessive, and tumor cells themselves generally appear unable to induce specific CD8+ T cells that recognize the encoded mutant gene product. In contrast, we find that mutant epitopes identified by CD8+ T cells stimulated by immunization with whole tumor cells induce cytolytic T cells to such mutant peptides. In fact, much or all of the response appears to be to a single mutant octapeptide that seems to be immunodominant. One possible reason for the failure of immunorecessive antigens to induce a response may be the presence of lower amounts of the antigen in the cancer cell, but other mechanisms are possible as well. For example, in the host bearing a growing tumor, neither purified proteins nor peptides might be known; thus, only immunodominant unique antigens may be able to restimulate and activate tumor-specific memory T cells that localize in the tumor following active immunization.

Lateral shearing interferometer based on two Ronchi phase gratings in series

Shearing interferometers are very popular and have a growing range of applications, especially in the field of optical testing. We describe a new kind of a lateral shearing interferometer. The lateral shear is produced by two Ronchi phase gratings in series. The phase can be shifted by a lateral movement of one grating relative to the other, and the amount of shear can easily be adjusted by variation of the distance of the gratings. The simplicity of the device is an important advantage, especially in the near IR.

Antigenic cancer cells grow progressively in immune hosts without evidence for T cell exhaustion or systemic anergy

One enigma in tumor immunology is why animals bearing malignant grafts can reject normal grafts that express the same nonself-antigen. An explanation for this phenomenon could be that different T cell clones react to the normal graft and the malignant cells, respectively, and only the tumor-reactive clonotypes may be affected by the growing tumor. To test this hypothesis, we used a T cell receptor transgenic mouse in which essentially all CD8(+) T cells are specific for a closely related set of self-peptides presented on the MHC class I molecule Ld. We find that the tumor expressed Ld in the T cell receptor transgenic mice but grew, while the Ld-positive skin was rejected. Thus, despite an abundance of antigen-specific T cells, the malignant tissue grew while normal tissue expressing the same epitopes was rejected. Therefore, systemic T cell exhaustion or anergy was not responsible for the growth of the antigenic cancer cells. Expression of costimulatory molecules on the tumor cells after transfection and preimmunization by full-thickness skin grafts was required for rejection of a subsequent tumor challenge, but there was no detectable effect of active immunization once the tumor was established. Thus, the failure of established tumors to attract and activate tumor-specific T cells at the tumor site may be a major obstacle for preventive or therapeutic vaccination against antigenic cancer.

Calculation of the dielectric properties of a protein and its solvent: theory and a case study

This paper presents a rigorous derivation of a theory for the calculation of the frequency-dependent dielectric properties of each component of the system protein/water/ions with the aim of enabling comparison to experimentally determined dielectric properties. We apply this theory to a very long (13.1 ns) molecular dynamics simulation of an HIV1 zinc finger peptide, its co-ordinated zinc ion, and two chloride ions in a box of SPC/E water molecules. We find the dielectric relaxation of the water molecules restricted compared to pure water, giving rise to a static dielectric constant for the water-component of only 47. The peptide is found to have a complicated dielectric relaxation behaviour, with a static dielectric constant of 15. We also calculate the frequency-dependent conductivity of the ions in this system. We analyze all contributions to the calculation of these dielectric properties and find that the coupling between the dielectric relaxation of the peptide and that of the water-component is particularly important for correctly describing the dielectric constant of the peptide.

An approach to the treatment of recurring polyarthralgia after jejunoileal bypass

Polyarthralgia after jejunoileal bypass (JI) is a well-documented complication. In the past, this was treated by antibiotic therapy, but definitive therapy uncommonly necessitated surgical reversal of the JI bypass. This case report discusses the etiology of arthralgias and presents a technique for its treatment without bypass reversal.

Visually-guided saccadic eye movements in adolescents at genetic risk for schizophrenia

Visually-guided saccades of 21 offspring of schizophrenic parents and 21 individually matched controls were compared with regard to the frequency of occurrence of saccadic hypometria and hypermetria, non-fixations, and omissions of target jumps. Target steps ranged from 10 to 60 degrees, and interstimulus intervals averaged 2.5 s; subjects were promised financial reward depending on performance. Recordings were carried out at the subjects' homes. To screen for cognitive abilities and psychopathological behavior, subjects were tested by means of an intelligence scale and a behavioral checklist. With large target steps (40-60 degrees), the high-risk group made significantly more grossly hypometric saccades (gain < or = 0.8) than the control group; responses to small target steps (10-30 degrees) exhibited a similar, albeit statistically not significant, trend. There were no significant differences with regard to the occurrence of hypermetria. Non-fixations scored marginally higher in the high-risks as compared to controls, but this was again not a significant difference. The incidence of omissions of saccades was very low in both groups. The results of the study suggest that subjects at genetic risk for schizophrenia may differ from controls by an increased incidence of conspicuously hypometric saccades. Clearly, this difference is not caused by a deficit of the saccadic motor circuitry proper; comparison to control data obtained with a similar experimental protocol suggests that it probably reflects an impaired internal control of saccades in the presence of distraction and stress. The relevance of saccades as indicators of a possible schizophrenic vulnerability is discussed.

The immunodominant antigen of an ultraviolet-induced regressor tumor is generated by a somatic point mutation in the DEAD box helicase p68

The genetic origins of CD8+ T cell-recognized unique antigens to which mice respond when immunized with syngeneic tumor cells are unknown. The ultraviolet light-induced murine tumor 8101 expresses an H-2Kb-restricted immunodominant antigen, A, that induces cytolytic CD8+ T cells in vivo A+ 8101 cells are rejected by naive mice while A- 8101 tumor cells grow. To identify the antigen H-2Kb molecules were immunoprecipitated from A+ 8101 cells and peptides were eluted by acid. The sensitizing peptide was isolated by sequential reverse-phase HPLC and sequenced using microcapillary HPLC-triple quadruple mass spectrometry. The peptide, SNFVFAGI, matched the sequence of the DEAD box protein p68 RNA helicase except for a single amino acid substitution, caused by a single nucleotide change. This mutation was somatic since fibroblasts from the mouse of tumor origin expressed the wild-type sequence. The amino acid substitution created an anchor for binding of the mutant peptide to H-2Kb. Our results are consistent with mutant p68 being responsible for rejection of the tumor. Several functions of p68, which include nucleolar assembly and inhibition of DNA unwinding, may be mediated through its IQ domain, which was altered by the mutation. This is the first description of a somatic tumor-specific mutation in the coding region of a nucleic acid helicase.

Radiation can inhibit tumor growth indirectly while depleting circulating leukocytes

The growth of certain UV-radiation-induced tumors is suppressed by T lymphocytes, but it has been proposed that non-T lymphocytes stimulate the growth of several of these tumors. In this study, the indirect effects of X irradiation on the growth of one such tumor in T-cell-deficient nude mice was tested. Even when the site of tumor cell injection was shielded, whole-body irradiation with 6 Gy before tumor challenge inhibited subsequent tumor growth significantly. The interval during which this indirect inhibition was observed correlated with the depletion of circulating leukocytes, which did not return to normal levels until 12-21 days after irradiation. These data are consistent with earlier results using an antibody to deplete Gr-1+ leukocytes and indicate that radiation can inhibit the growth of certain tumors indirectly without direct effects on the tumor cells or the tumor bed.

[Electrophysiologic correlates of selective attention in children and adolescents at increased risk of schizophrenia]

Electrophysiological correlates of selective attention in children and adolescents at high risk for schizophrenia. As part of a research project on electrophysiological correlates of attention in young subjects at high genetic risk for schizophrenia, auditory event-related potentials (ERPs) associated with selective attention and automatic information processing were recorded in 21 adolescent (offspring of at least one parent with schizophrenia) and 21 control subjects matched for age, sex and socioeconomic status. The experimental task was a dichotic listening task, and accuracy of counting target pips served as a psychometric control variable. The results showed group-related differences in the ERPs, with a significant reduction being present in the high-risk group concerning the amplitude of the fronto-precentrally located negative difference (Nd) wave and the F3 component elicited by selectively attended stimuli. Comparison of individual matched pairs showed that reduced Nds, characterized 14/21 high-risk individuals and reduced P3s 16/21. Moreover, there were significant correlations between ERP reductions and psychometric deficit (counting accuracy). Finally, 13 latencies tended to be prolonged in the high-risk group. Mismatch negativity (MMN), an ERP correlate of automatic information processing, did not differ significantly in the two groups, although there was a marked reduction in amplitude in the high-risk group. The ERP alterations point to impaired selective attention in a considerable proportion of subjects at high genetic risk for schizophrenia.

Unique tumor antigens redefined as mutant tumor-specific antigens

The extraordinary specificity of immune responses mediated by T cells against individual syngeneic tumors has led to the concept that many tumor antigens are 'unique'. The recent isolation of several T-cell-recognized unique antigens from various murine and human tumors has shown that the antigenic peptides are caused by somatic mutations and, thus, are truly tumor-specific. The following review summarizes current knowledge about these mutant tumor-specific antigens and their possible role in the development and progression of cancer. It also discusses some functional differences between mutant tumor-specific and shared tumor antigens, which generally represent unaltered peptides, also present on some normal cells.

Preattentive information processing as measured by backward masking and texton detection tasks in adolescents at high genetic risk for schizophrenia

Schizophrenic patients have consistently been reported to show deficits in preattentive information processing as demonstrated by impairments in visual backward masking and texton detection tasks. Texton detection refers to Julesz's texton theory, which defines a certain limited number of texton elements (e.g., one 'L' among many '+') that can be detected readily and simultaneously without attentional effort irrespective of the size of the rest of the visual field. The present study investigated whether deficits of preattentive information processing are more prevalent in a group of adolescents of high genetic risk for schizophrenia compared to matched control subjects. Although differences in the performance in visual backward masking tasks could not be detected with our experimental approach, preattentive texton detection was to a certain extent disturbed in subjects at risk. Moreover, subjects at risk did not show the advantage of the right hemisphere in processing texton elements which was found in the control group. This may point to a subtle dysfunction of the right hemisphere in the risk group. It is concluded from the present study that deficits in preattentive texton detection may represent an indicator for a schizophrenic disposition. However, further studies including other high risk groups, schizophrenics in remission and individuals with a schizotypal personality disorder are needed to confirm this hypothesis.

The influence of a protein on water dynamics in its vicinity investigated by molecular dynamics simulation

A system containing the globular protein ubiquitin and 4,197 water molecules has been used for the analysis of the influence exerted by a protein on solvent dynamics in its vicinity. Using Voronoi polyhedra, the solvent has been divided into three subsets, i.e., the first and second hydration shell, and the remaining bulk, which is hardly affected by the protein. Translational motion in the first shell is retarded by a factor of 3 in comparison to bulk. Several molecules in the first shell do not reach the diffusive regime within 100 ps. Shell-averaged orientational autocorrelation functions, which are also subject to a retardation effect, cannot be modeled by a single exponential time law, but are instead well-described by a Kohlrausch-Williams-Watts (KWW) function. The underlying distribution of single-molecule rotational correlation times is both obtained directly from the simulation and derived theoretically. The temperature dependence of reorientation is characterized by a strongly varying correlation time, but a virtually temperature-independent KWW exponent. Thus, the coupling of water structure relaxation with the respective environment, which is characteristic of each solvation shell, is hardly affected by temperature. In other words, the functional form of the distributions of single-molecule rotational correlation times is not subject to a temperature effect. On average, a correlation between reorientation and lifetimes of neighborhood relations is observed.

Conservative management strategy for pancreatitis-associated mesenteric venous thrombosis

Mesenteric venous thrombosis is a rare, but potentially lethal, complication of pancreatitis. Although management is usually directed toward the underlying pancreatitis, there is no standard defined for treatment of the associated mesenteric venous thrombosis. Anticoagulant therapy was chosen as treatment for the case presented in this report, but other management methods for this entity have been described in the literature. Based on our experience and review of the literature, a management strategy for patients with pancreatitis-associated mesenteric venous thrombosis has been developed.

Refractive-index measurement of gradient-index microlenses by diffraction tomography

Diffraction tomography is applied to reconstruction of the gradient-index distribution of planar gradient-index microlenses, fabricated by thermal ion exchange. Measurements of the single-phase projections are performed by phase-shifting interferometry For reconstruction, the Rytov approximation for smooth inhomogeneities is applied. Results are compared with measurement results from other methods and simulation results.

Immunodominance deters the response to other tumor antigens thereby favoring escape: prevention by vaccination with tumor variants selected with cloned cytolytic T cells in vitro

Variant cancer cells which arise from the parent tumor during tumor progression can escape immunity but retain antigens. We have mixed highly immunogenic (A+B+) murine parental cancer cells with less immunogenic (A-B+) variant cancer cells to construct a model of a cancer containing escape variants. When such mixtures of cancer cells were injected into normal mice, the variant cells grew out because immune responsiveness to the B antigen on the variant was hindered by dominance of the A antigen on the surrounding parental tumor cells. However, A-B+ variant cells inoculated alone at a separate site induced B specific cytolytic T cells and were rejected. Moreover, mice immunized with A-B+ cells rejected a challenge which contained a mixture of variant and parental cancer cells, while immunization with A+B+ cells was ineffective. Thus, variant tumor cells selected from parental tumor cells by cytolytic T cells in vitro can be used to induce protective immunity against variants expected to escape tumor immunity in vivo. The immunodominance of the A antigen may be related to its ability to induce a much more rapid CTL response than the B antigen, since we show in another model that the pre-existence of a CTL response to one antigen prevented the subsequent induction of CTL to another antigen injected at the same site, even if both antigens were equally efficient at inducing CTL. These results indicate that immunodominance can affect strong as well as weak antigens. Vaccination with individual antigens at separate sites rather than with multiple antigens at one site may, therefore, be needed to prevent tumor escape and tumor recurrence or to counteract infectious diseases.