Treatment of ovarian cancer with photodynamic therapy and immunoconjugates in a murine ovarian cancer model

In photodynamic therapy (PDT), photosensitisers accumulate somewhat preferentially in malignant tissues; photoactivation with appropriate wavelength of light release toxic molecular species which lead to tumour tissue death. In order to target ovarian cancer with increased specificity, a chlorin-based photosensitiser (chlorin e6 monoethylendiamine monoamide) was conjugated to OC125, a monoclonal antibody recognising an antigen expressed in 80% of non-mucinous ovarian cancers. In previous work, this immunoconjugate (IC) was shown to be selectively phototoxic to cancer cells from ovarian cancer patients ex vivo and to localise preferentially in ovarian cancer tissue in vivo. In this study we report results from in vivo phototoxicology and photodynamic treatment studies using this IC in a murine model for ovarian cancer. A comparison of single vs multiple treatments was also made. For in vivo experimentation, Balb C nude mice were injected with 30 x 10(6) NIH:OVCAR 3 cancer cells to create an ascitic tumour model. Animals were then given intraperitoneal injections of the immunoconjugate (0.5 mg kg-1). Twenty-four hours later the intraperitoneal surfaces were exposed to 656 nm light from an argon-ion pumped-dye laser (50 mW, 656 nm), using a cylindrical diffusing tip fibre. The overall treatment was given either once or multiply. No animals died from treatment complications. Twenty-four hours following one and three PDT treatments, the percentage of viable tumour cells in the ascites of the treated animals analysed ex vivo was 34% and 5% of control for one and three treatments respectively. With respect to survival, all control mice (n = 18) died between 30 and 50 days. However, for those treated three times (n = 10), 40% were still alive after 50 days, and for those treated four times (n = 12) 58% were alive after 50 days. Evaluation with log-rank test revealed a significant survival with intraperitoneal PDT compared with controls (P = 0.0006). These preliminary results suggest that PDT with an OC125 immunoconjugate may be an effective therapy for the management of advanced ovarian cancer. Clinical application of this therapy needs to be further optimised and may require multiple treatments, similar to fractionated radiation therapy and cyclic chemotherapy, in order to control malignant disease with acceptable toxicity to normal tissue.

Multimedia courseware. Transforming the classroom

This article describes a project that integrates faculty-developed computer courseware into a baccalaureate curriculum. The courseware was implemented as a teaching-learning strategy to enhance mastery of content and assist in development of decision-making skills. Curriculum, course, and unit objectives served as the foundation for the computer courseware lessons. The courseware is produced by a design team of six faculty. Computer lessons are interactive and actively involve students in the learning process. Students in six of eight clinical nursing courses are using faculty-developed courseware.

Partially polarized fiber-optic gyro

We present a new design for an all-fiber-optic gyroscope that makes use of a single-mode coil containing a Lyot depolarizer along with a partial depolarizer placed between the polarizer and the loop coupler. This design provides an optimal trade-off between the suppression of polarization errors and the reduction of drift errors arising from external magnetic f ields and changes in temperature.

Use of combinatorial peptide libraries to construct functional mimics of tumor epitopes recognized by MHC class I-restricted cytolytic T lymphocytes

Identification of cytolytic T lymphocyte (CTL) epitopes presented by major histocompatibility complex (MHC) class I molecules on tumor cells is critical for the design of active immunotherapy. We describe the use of combinatorial peptide libraries with defined amino acids in two MHC anchor positions to search for epitopes that are recognized by H-2Db- and Kb-restricted CTL specific for the mouse lymphoma EL4. An iterative strategy was used for screening libraries in which 16 amino acids were divided into 3 groups and 3 subgroups: alpha (AL, VT, FY); beta (GS, P, DE); gamma (KR, H, NQ). The proportions of each group and subgroup at individual peptide positions were changed in the library synthesis, and the effect of these changes on CTL activity was measured in a sensitive RMA-S cell assay. A single H-2Db epitope mimic was deduced from the original library that contained > 2 x 10(8) potential peptides and was at least 9 logs more potent than the original library. Immunization of syngeneic mice with this peptide elicited CTL that lysed EL4 cells as well as RMA-S cells pulsed with peptides isolated from Db molecules of EL4 cells, indicating functional similarity between the mimicking peptide and the naturally processed CTL epitope. Furthermore, adoptive transfer of such a CTL line had a therapeutic effect in mice with EL4 established as an ascites tumor. Two H-2Kb-restricted epitope mimics of the same tumor were also identified. Our method represents a novel approach for the construction of MHC class I-restricted targets that can serve as immunogens for active immunotherapy of cancer.

A new hepadnavirus endemic in arctic ground squirrels in Alaska

We present evidence for a novel member of the hepadnavirus family that is endemic in wild arctic ground squirrels (Spermophylus parryi kennicotti) in Alaska. This virus, designated arctic squirrel hepatitis virus (ASHV), was initially detected in the livers of animals bearing large hepatic nodules by nucleic acid hybridization with hepadnavirus probes and in plasma by cross-reactivity with antibodies to hepadnavirus surface and core antigens. The complete nucleotide sequence of the 3,302-bp-long ASHV genome was determined and compared with those of ground squirrel hepatitis virus (GSHV) and woodchuck hepatitis virus (WHV); all sequences were organized into four open reading frames, designated pre-C/C, pre-S/S, pol, and X. Despite roughly equivalent variability among the three rodent hepadnaviruses (around 16% base and 19% amino acid exchanges), ASHV appeared to be more closely related to GSHV than to WHV in phylogenetic analysis. Accordingly, preliminary studies of the pathology of ASHV infection suggested that ASHV may be a less efficient oncogenic agent than WHV. About one-third of aged animals maintained in captivity, including virus-infected as well as uninfected squirrels, developed large liver nodules, consisting of hepatocellular adenomas or carcinomas or nonmalignant lesions characterized by drastic microvesicular steatosis. ASHV-infected arctic ground squirrels may serve as a new model with which to analyze the contribution of hepadnavirus- and host-specific determinants to liver pathology and tumorigenesis.

Specific binding of Fyn and phosphatidylinositol 3-kinase to the B cell surface glycoprotein CD19 through their src homology 2 domains

CD19 is a B cell surface protein capable of forming non-covalent molecular complexes with a number of other B cell surface proteins including the CD21/CD81/Leu-13 complex as well as with surface immunoglobulin. CD19 tyrosine phosphorylation increases after B cell activation, and is proposed to play a role in signal transduction through its cytoplasmic domain, which contains nine tyrosine residues. Several second messenger proteins have been shown to immunoprecipitate with CD19, including p59 Fyn (Fyn), p59 Lyn (Lyn) and phosphatidylinositol-3 kinase (PI-3 kinase). These associations are predicted to occur via the src-homology 2 (SH2) domains of the second messenger proteins. Two of the cytoplasmic tyrosines in the CD19 cytoplasmic region contain the consensus binding sequence for the PI-3 kinase SH2 domain (YPO4-X-X-M). However, the reported consensus binding sequence for the Fyn and Lyn SH2 domains (YPO4-X-X-I/L) is not found in CD19. We investigated the capacity of CD19 cytoplasmic tyrosines to bind both Fyn and PI-3 kinase SH2-domain fusion proteins. In activated B cells, both Fyn and PI-3 kinase SH2-domain fusion proteins precipitate CD19. Using synthetic tyrosine-phosphorylated peptides comprising each of the CD19 cytoplasmic tyrosines and surrounding amino acids, we investigated the ability of the Fyn SH2 and PI-3 kinase SH2 fusion proteins to bind to the different CD19 cytoplasmic phosphotyrosine peptides. ELISA revealed that the two CD19 cytoplasmic tyrosine residues contained within the Y-X-X-M sequences (Y484 and Y515) bound preferentially to the PI-3 kinase SH2-domain fusion proteins. Two different tyrosines (Y405 and Y445) bound preferentially to the Fyn SH2-domain fusion protein via a novel sequence, Y-E-N-D/E, different from that previously reported for the Fyn SH2 domain. In precipitation studies, peptide Y484 was able to compete with tyrosine phosphorylated CD19 specifically for binding to the PI-3 kinase SH2 domain fusion proteins, while peptides Y405 and Y445 were able to compete specifically for binding to the Fyn SH2 domain fusion proteins. These results indicate that CD19 may be capable of binding both Fyn and PI-3 kinase concurrently, suggesting a mechanism for CD19 signal transduction, in which binding of PI-3 kinase to the Fyn SH3 domain results in activation of PI-3 kinase.

ZAP-70 and p72syk are signaling response elements through MHC class II molecules

Ligation of major histocompatibility complex (MHC) class II antigens expressed on antigen-activated human CD4+ T-lymphocytes induces early signal transduction events including the activation of tyrosine kinases, the tyrosine phosphorylation of phospholipase-C gamma 1 and the mobilization of intracellular calcium. Similar responses have been observed in B-cells following stimulation of MHC class II molecules, including the increased production of intracellular cAMP. In this report, we demonstrate that the ZAP-70 tyrosine kinase is a responsive signaling element following cross-linking of HLA-DR in class II+ T-cells, and that the homologous tyrosine kinase p72syk is stimulated in B-cells following ligation of class II antigens. Antibody mediated co-ligation of the T-cell antigen receptor (TCR/CD3) with class II molecules resulted in augmented tyrosine phosphorylation of ZAP-70. Comparable to antibody induced receptor ligation, bacterial superantigen (SEA and SEB) treatment of HLA-DR+ T-cells stimulated ZAP-70 tyrosine phosphorylation, consistent with class II transmembrane signaling by ligation of HLA-DR and V beta in cis. Modulation of the TCR/CD3 led to abrogation of class II induced ZAP-70 tyrosine phosphorylation, but did not result in sequestering of ZAP-70 from the cellular cytoplasm. Hyperphosphorylated ZAP-70 was associated with TCR/CD3 zeta-chain following cross-linking of HLA-DR, suggesting a mechanism for the TCR/CD3-dependence of class II induced signals in alloantigen-activated human T-cells. In both tonsillar B-lymphocytes and B-cell leukemia lines, p72syk was rapidly phosphorylated on tyrosine residues following HLA-DR cross-linking. Tyrosine phosphorylation of p72syk induced through ligation of either the B-cell antigen receptor or class II molecules was potently inhibited by herbimycin A. MHC class II ligation on B-lymphocytes resulted in cell death, which was both qualitatively distinct from Fas-induced apoptosis and partially protected by herbimycin A pretreatment. Thus, ligation of MHC class II molecules expressed on human lymphocytes stimulates the ZAP-70/p72syk family of tyrosine kinases, leading functionally to a tyrosine kinase-dependent pathway of receptor-induced cell death.

Coherence-collapsed 1.3-microm multimode laser diode for the fiber-optic gyroscope

Coherence-collapsing feedback applied to a 1.3-microm multimode laser diode is shown to sufficiently decouple the longitudinal modes and broaden their linewidth that the laser becomes suitable for use in a low-drift depolarized fiber-optic gyroscope.

Dual specificity of a monoclonal anti-idiotypic antibody for HIV-1 neutralizing monoclonals 110.3 and 110.4 as well as the V3 loop of gp120

Monoclonal antibodies (MAbs) 110.3 and 110.4 bind an epitope at the tip of the third hypervariable region (V3) of the envelope protein gp120 of human immunodeficiency virus type 1 (HIV-1). These MAbs inhibit HIV-induced syncytium formation and neutralize cell-free virus infection. Anti-idiotypic MAb alpha-id8, generated against 110.3, was found to mimic the V3 loop of gp120, as demonstrated by competition ELISA and by the generation of anti-anti-idiotypic sera which bound gp120 and a peptide representing the tip of the V3 loop. Interestingly, alpha-id8 itself also reacted specifically with both gp120 and the V3 loop peptide. Thus, alpha-id8 both mimics and binds directly to the V3 loop, suggesting that the V3 loop of gp120 may associate with itself.

Distribution of relative intensity noise in the signal and quadrature channels of a fiber-optic gyroscope

We show that white optical intensity noise is in general unevenly split between the signal and quadrature channels of a sinusoidally modulated fiber-optic gyroscope. At certain modulation depths this noise is almost totally relegated to the quadrature channel.

Slow-flow measurements and fluid dynamics analysis using the Fresnel drag effect

We have employed a Sagnac interferometer to measure small optical phase shifts induced by the Fresnel drag effect on moving media. The system detects volumetric flow rates of water as slow as 43 µL/min while maintaining a small pressure drop across the measuring pipe. Velocity profiles and turbulence measurements of flowing water are also demonstrated and discussed.

Photoimmunotherapy and biodistribution with an OC125-chlorin immunoconjugate in an in vivo murine ovarian cancer model

Photodynamic therapy (PDT) is an experimental approach to the treatment of neoplasms in which photosensitisers (PSs) accumulated in malignant tissues are photoactivated with appropriate wavelengths of light. The target specificity of PSs may be improved by linking them with carrier macromolecules such as monoclonal antibodies (MAbs). OC125 is a murine MAb that recognises the antigen CA 125, which is expressed on 80% of non-mucinous ovarian tumours. A chlorin derivative conjugated to OC125 was shown to be selectively phototoxic to ovarian cancer and other CA 125-positive cells in vitro and ex vivo. We now report in vivo studies using an ascitic Balb/c nude mouse ovarian cancer model. Ascites was induced by intraperitoneal injection of cells from the human ovarian cancer cell line NIH:OVCAR3. Six weeks after injection, when the animals had developed ascites, biodistribution studies were carried out by injecting the immunoconjugate (IC) or free PS intraperitoneally and sacrificing the animals at 3, 6, 12, 24, 48, 72 and 168 h later. The PS was quantitated by extraction and fluorescence spectroscopy. For both the IC and free PS, peak tumour concentrations were reached at 24 h; however, the absolute concentrations for the IC were always higher (2- to 3-fold) than the free PS. Tumour to non-tumour ratios at 24 h for the IC were 6.8 for blood, 6.5 for liver, 7.2 for kidney, 5.7 for skin and 3.5 for intestine. Evaluation of viable tumour cells in ascites following in vivo PDT with a single light exposure demonstrated a dose-dependent relationship with fluence and IC concentration. However, there was significant treatment-related toxicity at all fluences. With multiple low-dose treatments, the percentage of viable tumour cells was also significantly reduced and there were no treatment-related deaths. These data suggest that, while photoimmunotherapy remains promising as a new treatment modality for ovarian cancers, careful quantitative dosimetry of both IC and light may need to be combined with multiple treatments (as with radiation therapy and chemotherapy) to control malignant disease yet maintain acceptable toxicity in vivo.

Library resources for problem-based learning: the program perspective

The impact of a problem based curriculum has been the subject of increasing interest, as evidenced by several recent articles on the subject [1-4]. McMaster was able to design its library to serve a problem-based curriculum, but since there had been no prior experience with such a curriculum, the library was designed to meet needs that could only be guessed at [5]. In addition, the library serves the needs of a research intensive faculty. How the curriculum and the library have interacted over the past 25 years may be helpful to other schools considering problem-based learning.

Structure-activity analysis of the antitumor and hemolytic properties of the amphiphilic alpha-helical peptide, C18G

The in vitro antitumor and hemolytic activities of analogs of peptide C18G were compared in order to elucidate important structural features which affect cytotoxicity. The sequence of C18G, a basic peptide which can form an amphiphilic alpha-helix, is a derivative of the carboxyl terminus of human platelet factor IV. The results demonstrate that both amphiphilicity and helicity are essential for peptide activity, and that addition of a negatively charged amino acid results in decreased cell lysis. Whereas peptides exhibiting various degrees of potency did not differ with respect to helical content, an increase in peptide hydrophobicity did correlate with an increase in antitumor and hemolytic activity, as well as susceptibility to inhibition by serum. Higher hydrophobicity could be associated with improved ability to insert into the cell membrane. The position or context of specific residues within an amphiphilic peptide can also be important for activity. Furthermore, an increase in tumoricidal activity is not always accompanied by an increase in hemolytic activity or susceptibility to inhibition by serum. Possible reasons for the lower sensitivity of RBCs versus tumor cells to peptide cytotoxicity are discussed. Finally, compared with structurally idealized amphiphilic alpha-helical peptides, non-idealized peptides can possess higher tumoricidal activity, but are less hemolytic and less susceptible to serum inhibition.

Caesarean section in a diabetic patient with a recent myocardial infarction

This is a report of a 38-yr-old parturient with multiple medical problems including diabetes mellitus, bronchial asthma, chronic myelogenous leukaemia, pre-eclampsia and a recent myocardial infarction. After medical management in the coronary care unit, it was decided to proceed with a Caesarean section. The choice of anaesthetic was made by the patient and had to be modified in accordance with her medical condition. Cardiovascular monitoring included PA catheterisation and transoesophageal echocardiography. A general anaesthetic was performed using fentanyl, thiopentone and succinylcholine. The outcome was satisfactory for both parturient and baby.

Two-mode fiber-optic bending sensor with temperature and strain compensation

A temperature- and strain-compensated two-mode fiber-optic bending sensor is presented. This sensor has the unique ability to measure bending over complex and arbitrary paths, using a strictly passive sensing tether. Experimental evidence demonstrates the properties of the sensor and the effectiveness of the compensation technique.

Lysis of ras oncogene-transformed cells by specific cytotoxic T lymphocytes elicited by primary in vitro immunization with mutated ras peptide

Ras protooncogenes are activated by characteristic point mutations in a wide variety of malignancies. The expressed p21ras proteins are oncogenic by virtue of single substituted amino acids, usually at position 12 or 61 of the 189-residue p21ras protein. In the current study, the ability of class I major histocompatibility complex (MHC)-restricted T cells to recognize the altered segment of a transforming p21ras protein and to lyse cells transformed by the corresponding ras oncogene was examined. Synthetic ras peptides encompassing the common activating substitution of leucine for glutamine at position 61 were constructed with an amino acid motif appropriate for binding to the H-2Kb murine class I MHC molecule. Cytotoxic T lymphocytes (CTL) specific for bound ras leucine 61 peptide were elicited by in vitro immunization of normal lymphocytes with synthetic peptides. The ras peptide-induced CTL specifically lysed syngeneic fibroblasts transformed by an activated ras gene encoding oncogenic p21ras protein containing the same single amino acid substitution. Thus, in some circumstances, mutated p21ras protein can serve as a tumor-specific antigen.

Human T and B lymphocytes express a structurally conserved focal adhesion kinase, pp125FAK

Clustering of beta 1-integrins on adherent cells with antibodies or ligands results in increased tyrosine phosphorylation and activation of a novel focal adhesion tyrosine kinase, pp125FAK. The genes encoding pp125FAK have been cloned previously from both chicken and mouse cDNA libraries, and the deduced amino acid sequences are nearly identical (94%). Two synthetic peptides derived from sequences at the carboxyl terminus of chicken pp125FAK were conjugated to ovalbumin to generate rabbit heteroantisera. Human pp125FAK was immunodetected in both T and B lymphocytes with these antisera. A basal state of pp125FAK tyrosine phosphorylation was observed in T and B lymphocytes, and its expression level was in general augmented among human T- and B-cell leukemia/lymphoma lines. Additionally, the full-length sequence of human T-cell pp125FAK (huT-FAK) was derived from a Jurkat T-cell cDNA library. huT-FAK is structurally identical with both mouse and chicken FAK, and shares 95% amino acid identity with chicken pp125FAK and has 97% homology with the mouse sequence. This high degree of evolutionary conservation between species suggests that pp125FAK is likely to have a crucial function in the cell. Expression of the full-length huT-FAK gene in COS cells showed an immunologically indistinct human pp125FAK protein compared with the endogenous primate pp125FAK. Taken together, the data indicate that this structurally conserved human T-cell pp125FAK likely functions in T- and B-cell lineages, and its altered expression in human lymphocyte tumor cell lines may contribute to their transformed phenotype.

Comparison of left ventricular mass and geometry in black and white patients with essential hypertension

To assess racial difference in cardiac responses to elevated blood pressure, we compared echocardiographic measurements of left ventricular (LV) mass and the wall thickness to chamber dimension ratio (relative wall thickness) in 380 white and 47 black patients with uncomplicated essential hypertension consecutively enrolled in echocardiographic research studies at The New York Hospital Hypertension Center. Diastolic blood pressure and weight were slightly greater in black as compared with white subjects (104 +/- 18 v 98 +/- 11 mm Hg; P = .014 and 82 +/- 17 v 77 +/- 15 kg; P = .037, respectively), however the groups were similar with respect to age, duration of hypertension, cholesterol level, cigarette smoking, past use of antihypertensive therapy, family history of heart disease, and height. On average, LV mass indexed for body surface area and relative wall thickness were significantly greater in blacks than whites (119 v 105 g/m2; P = .02 and 0.46 v 0.39; P = .003) and blacks had twice the prevalence of LV hypertrophy (41% v 19%; P < .001) or concentric remodeling (21% v 12%; P < .05). The magnitude of increased LV mass and relative wall thickness in blacks was similar in men (132 v 110 g/m2; P = .01 and 0.44 v 0.39; P = .04) and in women (107 v 94 g/m2; P = .11 and 0.48 v 0.39; P = .02). In multivariate analyses, systolic blood pressure, age, and race were consistently predictors of increased LV mass and abnormal cardiac geometry. Cholesterol level was not independently associated with increased LV mass but was weakly associated with increased relative wall thickness.(ABSTRACT TRUNCATED AT 250 WORDS)

Evaluating quantitative measures of grammatical complexity in spontaneous speech samples

The validity of MLU and a measure of syntactic complexity were tested against LARSP on spontaneous speech samples from 87 children, ranging in age from 1;6 to 4;9. Change in some LARSP clausal measures was found across MLU stages up to MLU 4.5. For the measure of syntactic complexity, no such ceiling was found for the clausal connectivity score in LARSP or for average clausal complexity in LARSP. Neither MLU nor the measure of syntactic complexity indexed LARSP phrasal complexity. It is concluded that MLU is a valid measure of clausal complexity up to 4.5 and that our measure of syntactic complexity is more valid at more advanced stages.

Predicting the polarization dependence of two-mode fiber interferometers from the far-field intensity patterns

We show that the polarization dependence of the interference between differing spatial modes of an optical fiber under axial strain can be experimentally determined purely from the far-field intensity patterns of those modes.