The evolution from life insurance to financial engineering.

Since the mid-1980s, the share of household net worth intermediated by US financial institutions has shifted from defined benefit plans to life insurers and defined contribution plans. Life insurers have primarily grown through variable annuities, which are mutual funds with longevity insurance, a potential tax advantage, and minimum return guarantees. The minimum return guarantees change the primary function of life insurers from traditional insurance to financial engineering. Variable annuity insurers are exposed to interest and equity risk mismatch and their stock returns were especially low during the COVID-19 crisis. We consider regulatory changes, such as more detailed financial disclosure and standardized stress tests, to monitor potential risk mismatch and to ensure stability of the insurance sector.

Use of anti-cancer drugs, mitocans, to enhance the immune responses against tumors.

Cytotoxic drugs in cancer therapy are used with the expectation of selectively killing and thereby eliminating the offending cancer cells. If they should die in an appropriate manner, the cells can also release danger signals that promote an immune reaction that reinforces the response against the cancer. The identity of these immune-enhancing danger signals, how they work extra- and intracellularly, and the molecular mechanisms by which some anti-cancer drugs induce cell death to bring about the release of danger signals are the major focus of this review. A specific group of mitocans, the vitamin E analogs that act by targeting mitochondria to drive ROS production and also promote a more immunogenic means of cancer cell death exemplify such anti-cancer drugs. The role of reactive oxygen species (ROS) production and the events leading to the activation of the inflammasome and pro-inflammatory mediators induced by dying cancer cell mitochondria are discussed along with the evidence for their contribution to promoting immune responses against cancer. Current knowledge of how the danger signals interact with immune cells to boost the anti-tumor response is also evaluated.

Alpha-tocopheryl succinate induces apoptosis by targeting ubiquinone-binding sites in mitochondrial respiratory complex II.

Alpha-tocopheryl succinate (alpha-TOS) is a selective inducer of apoptosis in cancer cells, which involves the accumulation of reactive oxygen species (ROS). The molecular target of alpha-TOS has not been identified. Here, we show that alpha-TOS inhibits succinate dehydrogenase (SDH) activity of complex II (CII) by interacting with the proximal and distal ubiquinone (UbQ)-binding site (Q(P) and Q(D), respectively). This is based on biochemical analyses and molecular modelling, revealing similar or stronger interaction energy of alpha-TOS compared to that of UbQ for the Q(P) and Q(D) sites, respectively. CybL-mutant cells with dysfunctional CII failed to accumulate ROS and underwent apoptosis in the presence of alpha-TOS. Similar resistance was observed when CybL was knocked down with siRNA. Reconstitution of functional CII rendered CybL-mutant cells susceptible to alpha-TOS. We propose that alpha-TOS displaces UbQ in CII causing electrons generated by SDH to recombine with molecular oxygen to yield ROS. Our data highlight CII, a known tumour suppressor, as a novel target for cancer therapy.

Use of cytokines in cancer vaccines/immunotherapy: recent developments improve survival rates for patients with metastatic malignancy.

Historically, patients with disseminated cancer have had poor prognoses and chemotherapy has been of little benefit. However, several different avenues of clinical research are providing reasons for hope. The advent of cytokine immunotherapy, particularly in combination with chemotherapy (biochemotherapy) has seen significantly improved outcomes for metastatic disease. Early biochemotherapy trials often revealed more than 20% complete responses. Unfortunately, Phase III trials have not confirmed earlier expectations for reasons that are not clear, but may reflect the inclusion of patients with refractory brain or other metastases in later trials. More recently, cancer vaccine therapies have provided significantly improved patient survival rates. It is not uncommon for 5-year survival rates of post-surgical patients recovering from metastatic malignancy who receive cancer vaccine therapy to reach more than 50%. Cytokines have become an integral part of cancer therapy and are also under trial together with cancer vaccines as post-surgical adjuvant therapies providing significant gains in long term survival rates. New insights from several different areas of research into the properties of tumour cells and their significance for immunosurveillance point to the importance of the tumour cells themselves as antigen presenting cells. Recent developments with genetically deficient animals and cancer cells have provided greater understanding at the molecular level of the importance of a functioning antigen presenting system operating inside tumour cells. This new knowledge offers support for further enhancing patient survival by combining previous therapies such as use of cytokines in biochemotherapy together with immunization using cytokine activated whole cell cancer vaccines in the future.

IFI60/ISG60/IFIT4, a new member of the human IFI54/IFIT2 family of interferon-stimulated genes.

We report the cloning and sequencing of a full-length cDNA encoding a new member of the human IFI54 (HGMW-approved symbol IFIT2) gene family, designated IFI60 (HGMW-approved symbol IFIT4). The upstream regulatory region of IFI60 shows conservation in structure with that of the IFI54 and IFI56 (HGMW-approved symbol IFIT1) genes, each containing two interferon-stimulated response elements upstream of a conserved TATA box. We have established a partial gene map of the IFI54 gene family by analysis of YAC library clones. All four members of the human family are clustered together at chromosome 10q23.3. It is proposed that the four members of the IFI54 gene family evolved by a series of duplication events from a common gene of origin.

IFN-gamma priming up-regulates IFN-stimulated gene factor 3 (ISGF3) components, augmenting responsiveness of IFN-resistant melanoma cells to type I IFNs.

IFN-stimulated gene factor 3 (ISGF3) mediates transcriptional activation of IFN-sensitive genes (ISGs). The component subunits of ISGF3, STAT1alphabeta, STAT2, and p48-ISGF3gamma, are tyrosine phosphorylated before their assembly into a complex. Subsequently, the ISGF3 complex is translocated to the nucleus. We have recently established that the responsiveness of human melanoma cell lines to type I IFNs correlates directly with their intracellular levels of ISGF3 components, particularly STAT1. In the present study, we show that pretreating IFN-resistant melanoma cell lines with IFN-gamma (IFN-gamma priming) before stimulation with type I IFN also results in increased levels of ISGF3 components and enhanced DNA-binding activation of ISGF3. In addition, IFN-gamma priming of IFN-resistant melanoma cell lines increased expression of type I IFN-induced ISG products, including ISG54, 2'-5'-oligoadenylate synthase, HLA class I, B7-1, and ICAM-1 Ags. Furthermore, IFN-gamma priming enhanced the antiviral effect of IFN-beta on the IFN-resistant melanoma cell line, MM96. These results support a role for IFN-gamma priming in up-regulating ISGF3, thereby augmenting the responsiveness of IFN-resistant melanoma cell lines to type I IFN and providing a molecular basis and justification for using sequential IFN therapy, as proposed by others, to enhance the use of IFNs in the treatment of melanoma.

Interferon-resistant human melanoma cells are deficient in ISGF3 components, STAT1, STAT2, and p48-ISGF3gamma.

The mechanism of IFN resistance was examined in three long-term cell lines, SK-MEL-28, SK-MEL-3, and MM96, exhibiting significant variation in responsiveness to the antiproliferative and antiviral effects of type I IFNs. The JAK-STAT components involved in IFN signal transduction were analyzed in detail. After exposure to IFN, activation of the IFN type I receptor-linked tyrosine kinases, JAK-1 and TYK-2, was detected at similar levels in both IFN-sensitive and IFN-resistant cell types, indicating that IFN resistance did not result from a deficiency in signaling at the level of receptor-associated kinase activation. However, analysis of ISGF3 transcription factor components, STAT1, STAT2, and p48-ISGF3gamma, revealed that their expression and activation correlated with cellular IFN responsiveness. The analysis was extended to also include IFN-sensitive primary melanocytes, three additional IFN-resistant melanoma cell lines, and seven cell cultures recently established from melanoma patient biopsies. It was consistently observed that the most marked difference in ISGF3 was a lack of STAT1 in the resistant versus the sensitive cells. Transfection of the IFN-resistant MM96 cell line to express increased levels of STAT1 protein partially restored IFN responsiveness in an antiviral assay. We conclude that a defect in the level of STAT1 and possibly all three ISGF3 components in IFN-resistant human melanoma cells may be a general phenomenon responsible for reduced cellular responsiveness of melanomas to IFNs.

Resistance of melanoma cell lines to interferons correlates with reduction of IFN-induced tyrosine phosphorylation. Induction of the anti-viral state by IFN is prevented by tyrosine kinase inhibitors.

Clinical and experimental studies examining the action of IFNs on human malignant melanomas and melanoma cell lines have shown that this cancer cell type is frequently IFN resistant. In the present study, the IFN responsiveness of five melanoma cell lines, SK-MEL-28, SK-MEL-3, MM96, HT-144, and Hs 294T, as determined by the levels of IFN-induced expression of the antiviral proteins, 100 kDa 2',5'-oligoadenylate synthetase (OAS) and Mx Ag, was shown to correlate with the IFN responsiveness of the five lines measured in antiproliferative and antiviral assays. Three of the lines, SK-MEL-28 (IFN sensitive), SK-MEL-3 (moderately IFN sensitive), and MM96 (IFN insensitive) were analyzed further to ascertain their relative levels of IFN-activated signal transduction. Pretreatment of the three melanoma cell lines with the tyrosine kinase inhibitors, Herbimycin A or Genistein, produced a dose-dependent inhibition of the antiviral action of IFN-alpha, -beta, and -gamma and the induction of OAS by IFN-beta. Thus, induction of the antiviral state in melanoma cells by IFN requires activation of tyrosine kinase-dependent signaling pathways. Furthermore, the IFN responsiveness of three melanoma cell lines could be correlated with the ability to detect by immunoblotting of SDS-PAGE displays of cell lysates, IFN-induced tyrosine phosphorylated cellular proteins in the range m.w. 80 to 130 kDa. This induction was also sensitive to the tyrosine kinase inhibitors Herbimycin A and Genistein. Based on these results, we propose that the IFN-resistant melanoma cell lines examined contain a deficiency early in the IFN signal transduction pathway resulting in a reduced potential for IFN-induced tyrosine phosphorylation and a lack of responsiveness to IFN.

cDNA sequence identity for the type I interferon receptor subunit from cell lines of widely differing responsiveness to interferon.

Melanoma cell lines exhibit strikingly different sensitivity to the antiproliferative effects of interferon. cDNAs encoding the Type I interferon receptor subunit were amplified by polymerase chain reaction, using as template RNA isolated from three melanoma cell lines displaying greater than 100 fold range in their sensitivity to the antiproliferative effects of IFN-beta. Comparison of the cDNA sequences obtained with the published cDNA sequence from the highly interferon-sensitive lymphoid cell line Daudi revealed only one base change that leads to a conservative amino acid substitution. It is concluded that the cellular differences in responsiveness to interferon, of the melanoma cell lines tested, do not arise from the expression of variants of the cloned Type I interferon receptor subunit.

In vitro heart valve testing: steady versus pulsatile flow.

The design of artificial heart valves has traditionally been based on the development of a prototype device which was then subjected to extensive laboratory testing in order to confirm its suitability for clinical use. In the past the in vitro assessment of a valve's performance was based principally on the measurement of parameters such as pressure difference, regurgitation and, more recently, energy losses. Such measurements can be defined as being at the 'macro' level and rarely show any clinically significant differences amongst currently available prostheses. The analytical approach to flow through heart valves has previously been hampered by difficulties experienced in solving the relevant equations of flow particularly in the case of pulsatile conditions. Computational techniques are now available which enable appropriate solutions to be obtained for these problems and consequently provide an opportunity for detailed examination of the 'micro' level of flow disturbances exhibited by the different valves. This present preliminary study is designed to illustrate the use of such an analytical approach to the flow through prosthetic valves. A single topic has been selected for this purpose which is the comparative value of steady versus pulsatile flow testing. A bileaflet valve was chosen for the analysis and a mathematical model of this valve in the aortic position of the Sheffield Pulse Duplicator was created. The theoretical analysis was carried out using a commercially available Computational Fluid Dynamics package, namely, FIDAP, on a SUN MICROSYSTEMS 10-30 workstation.(ABSTRACT TRUNCATED AT 250 WORDS)

Mitochondrial respiratory chain inhibitors induce apoptosis.

In this paper the specific mitochondrial respiratory chain inhibitors rotenone and antimycin A and the highly specific mitochondrial ATP-synthase inhibitor oligomycin are shown to induce an apoptotic suicide response in cultured human lymphoblastoid and other mammalian cells within 12-18 h. The mitochondrial inhibitors do not induce apoptosis in cells depleted of mitochondrial DNA and thus lacking an intact mitochondrial respiratory chain. Apoptosis induced by respiratory chain inhibitors is not inhibited by the presence of Bcl-2. We discuss the possible role of mitochondrial induced apoptosis in the ageing process and age-associated diseases.

A colourimetric dye assay to detect anti-viral activity of interferons: sensitivity for measuring cellular responsiveness to interferons.

Colourimetric assays which rely on the conversion of metabolic dyes are becoming increasingly used for measuring cell proliferation and cytotoxicity. We developed a method for measuring cellular responsiveness to interferons based on the property of interferons to induce cell defenses to virus-mediated killing. The assay has several advantages over previous assays for measuring anti-viral activity and efficiently detected cytoprotective responses to human interferon of five human melanoma cell lines infected with Semliki Forest virus. The melanoma cell lines showed a varying cytoprotective response to interferons alpha 2, alpha 4, beta and gamma, in agreement with the results of previous assays for measuring melanoma cell responsiveness to interferons based upon the inhibition of cell growth (1).

Two novel protein-tyrosine kinases, each with a second phosphotransferase-related catalytic domain, define a new class of protein kinase.

The protein-tyrosine kinases (PTKs) are a burgeoning family of proteins, each of which bears a conserved domain of 250 to 300 amino acids capable of phosphorylating substrate proteins on tyrosine residues. We recently exploited the existence of two highly conserved sequence elements within the catalytic domain to generate PTK-specific degenerate oligonucleotide primers (A. F. Wilks, Proc. Natl. Acad. Sci. USA 86:1603-1607, 1989). By application of the polymerase chain reaction, portions of the catalytic domains of several novel PTKs were amplified. We describe here the primary sequence of one of these new PTKs, JAK1 (from Janus kinase), a member of a new class of PTK characterized by the presence of a second phosphotransferase-related domain immediately N terminal to the PTK domain. The second phosphotransferase domain bears all the hallmarks of a protein kinase, although its structure differs significantly from that of the PTK and threonine/serine kinase family members. A second member of this family (JAK2) has been partially characterized and exhibits a similar array of kinase-related domains. JAK1 is a large, widely expressed membrane-associated phosphoprotein of approximately 130,000 Da. The PTK activity of JAK1 has been located in the C-terminal PTK-like domain. The role of the second kinaselike domain is unknown.

Rupture of the oesophagus during cricoid pressure.

Rupture of the oesophagus occurred during the application of cricoid pressure at induction of anaesthesia when the patient vomited. The patient, who was bleeding from a gastric ulcer, was found to have a lower oesophageal tear which, although repaired at operation, resulted in a fatal mediastinitis.

The application of the polymerase chain reaction to cloning members of the protein tyrosine kinase family.

Degenerate oligodeoxyribonucleotide (oligo) primers derived from amino acid (aa) sequence motifs held in common between all members of the protein tyrosine kinase (PTK) family were used to prime the amplification of PTK-related sequences from a variety of murine cDNA sources, including the haemopoietic cell lines, FDC-P1 and WEHI-3B D+, peritoneal macrophages and whole brain. Several parameters, such as the length (short, i.e., less than 20 nucleotides (nt) vs. long, i.e., greater than 30 nt) and degeneracy (i.e., moderately degenerate vs. highly degenerate) of the oligo primers and the temperature of the extension phase of the reaction, were examined. The data from these analyses suggest that the most effective type of primer in this application of the polymerase chain reaction is a short, moderately degenerate oligo such as that which might be derived from the small patches of aa sequence homology that are frequently found to be held in common among members of protein families. In addition to a number of previously described PTK sequences, a novel mammalian PTK-related sequence was uncovered.

Structural variants of human T200 glycoprotein (leukocyte-common antigen).

Structural variation in the primary structure of human T200 glycoprotein has been detected. Three cDNA variants have been characterized each of which encode T200 molecules that differ in size as a result of sequence differences in their amino-terminal regions. The largest form of the molecule is distinguished from the smallest by an insert of 161 amino acids, after the first eight amino-terminal residues. The other variant has an insert at the same location of 47 amino acids identical to residues 75-121 in the larger insert. Both extra domains are rich in serine and threonine residues and are likely to display multiple O-linked oligosaccharides. These structural variants which probably arise by cell-type-specific alternative splicing provide a molecular basis for the previously observed structural and antigenic heterogeneity of T200 glycoprotein. In addition to the variable amino-terminal region, the external domain of human T200 glycoprotein consists of a second cysteine-rich region of about 400 amino acids, a single transmembrane-spanning region and a large cytoplasmic domain of 707 amino acids shared by all of the structural variants and highly conserved between species. The gene encoding human T200 is located on the long arm of chromosome 1.

Cell-lineage antigens of the stem cell-megakaryocyte-platelet lineage are associated with the platelet IIb-IIIa glycoprotein complex.

The stem cell-platelet lineage is uniquely defined by platelet cell-lineage antigens. These antigens are present on all stem cells measured by the spleen colony assay and become restricted to the platelet cell lineage as differentiation proceeds. In this study, anti-platelet serum (APS) has been used to identify cells in the bone marrow that express platelet cell-lineage antigens and to identify platelet cell surface molecules expressing these antigens. Anti-platelet IgG extensively absorbed with brain, thymus, and peritoneal cells bound selectively to stem cells, megakaryocyte progenitor cells (Mk-CFC), and megakaryocytes in CBA mouse bone marrow and to blood platelets. No other hemopoietic cell type, tissue, cell line, or tumor cell bound significant amounts of antibody against platelet cell-lineage antigens as determined by ability to absorb the anti-stem cell activity in APS. Studies with lactoperoxidase-labeled platelets showed that two major iodinated proteins of Mr = 114,000 and 138,000 were immunoprecipitated with APS and with antiserum that had been extensively absorbed. These proteins correspond to the platelet IIb-IIIa glycoprotein complex, which is known to express receptors for collagen and fibrinogen, molecules known to influence hemopoietic cell proliferation and tumor cell growth. A panel of six monoclonal antibodies against human IIb-IIIa inhibited spleen colony formation by 17% to 100%, J15 and A5.15 also being cytotoxic for granulocyte-macrophage progenitor cells and Mk-CFC. Other platelet monoclonal antibodies did not inhibit spleen colony formation. Although APS inhibited fibrinogen binding to platelets and platelet aggregation, these activities were greatly reduced with absorbed antiserum. Furthermore, fibrinogen treatment of bone marrow did not block the anti-stem cell activity in APS. Thus the evidence is consistent with expression of platelet cell-lineage antigens on the platelet IIb-IIIa glycoprotein complex at a site removed from the fibrinogen binding site.