Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0023418 (leukemia)
 93,477 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Molecular biology techniques are now a vital part of hepatitis virology, with a central role in studies of diagnosis, epidemiology, virology, pathogenesis, and natural history of infection. Cloning of the genome of hepatitis E virus has allowed its tentative classification as a calici- or related virus, and is the first step toward the development of a vaccine. Long-term implications of hepatitis C for groups such as children with hemophilia, thalassemia, and even leukemia can be better understood by comparison of virus load measured by molecular amplification of the plasma viral RNA with the serologic and clinical status of the respective cohorts of children. A new vaccine for hepatitis A has been licensed in several European countries, and recent experience with severe hepatitis in infants after unexpected transmission of hepatitis B from anti-hepatitis B e positive mothers reemphasizes the value of universal hepatitis B immunization programs. Mother-to-infant transmission of hepatitis C virus has now been well documented, but there are still insufficient data on the dynamics of this, particularly in the absence of passive immunoprophylaxis or a vaccine, to permit recommendations regarding the management of individual pregnancies or deliveries. There is especially too little information to suggest whether breast feeding may be an important mechanism for transmission.
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PMID:Hepatitis viruses and protection against infection in children. 837 24

The presence of viruses in blood cells or plasma from asymptomatic donors is the major risk of transmitting an infectious agent through blood transfusion. The main viruses involved are hepatitis viruses and retroviruses. The risk of transmitting hepatitis B virus (HBV) and hepatitis C virus (HCV) has been progressively and efficiently reduced in the last years by the successive introduction of hepatitis B surface antigen (HBsAg) screening, elevated serum alanine aminotransferase (ALT), antibody to hepatitis B core (HBc Ab), and more recently antibody to hepatitis C virus (HCV Ab). The risk of transmitting human retroviruses like human immunodeficiency virus (HIV) and human T-cell leukemia/lymphoma virus (HTLV) has also been reduced drastically thanks to screening for corresponding antibodies. However, except for HBs Ag screening, the immunoassays used for HCV, HIV, or HTLV only detect antibodies. Therefore, although they are infectious, a few blood units may be not discarded. The efficacy of preventive measures depends on the incubation time, the infectivity during this silent phase, and the sensitivity of screening procedures. Human cytomegalovirus (HCMV) and parvovirus B 19 are responsible for common infections. Consequently, 30% to more than 50% adults have serologic evidence of past infection. However, both viruses may cause severe primo-infections in some circumstances, especially in pregnant women or immunodeficient individuals.
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PMID:[Viral risks associated with blood transfusion]. 838 12

The uptake and distribution of phosphorothioate oligodeoxynucleotides by human cells were studied using 35S-labeled 28-mer phosphorothioate oligodeoxycytidine [S-(dC)28]. Accumulation of intracellular S-(dC)28 was found to be higher in the carcinoma cells (grown in monolayers) than in the leukemia cells (grown in suspension culture). A hepatoma cell line transfected with hepatitis B virus, 2215, was chosen for further studies. The uptake of S-(dC)28 was partially dependent on temperature and energy. The intracellular concentration was significantly higher than that in the medium and the amount accumulated was dependent on the extracellular concentration. It appears that the uptake of S-(dC)28 involves mechanisms of both fluid-phase pinocytosis and adsorptive endocytosis. Neither oligonucleotides nor 5'-phosphorylated nucleotides inhibited S-(dC)28 uptake. Unlike horseradish peroxidase, which was primarily associated with endosomes once it was taken into the cell, S-(dC)28 was found to be present in both nuclear and cytoplasmic fractions. Efflux of S-(dC)28 from the cell was multiphasic; a trapping mechanism that could be due to a potent interaction of S-(dC)28 with cellular proteins was implicated. This trapping mechanism could be responsible for the lack of biological activity such as cytotoxicity and antisense activity of phosphorothioate oligodeoxynucleotides in some human cells.
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PMID:Cellular pharmacology of phosphorothioate homooligodeoxynucleotides in human cells. 842 68

Active immunization against measles, Haemophilus influenza B, tetanus, diphtheria, hepatitis B, influenza, poliomyelitis, and, when indicated varicella and pneumococcus induces long-lasting immunologic protection in most healthy pediatric vaccine recipients. Among children receiving immunosuppressive therapy for cancer, possible early loss of specific immunity acquired from prior vaccination or disease, and likely diminished responsiveness to initial or booster vaccination must be considered. In addition, the safety of vaccine administration requires separate study in this population. Published evidence demonstrates preservation of vaccine-induced antibody titers against tetanus, diphtheria, poliomyelitis and (in children treated for lymphoma) pneumococcus. In contrast, prior immunity to varicella, influenza, and hepatitis B (when naturally acquired), and measles (acquired by vaccination) is compromised during and/or after antineoplastic therapy. Studies of immunologic protection acquired by prior vaccination against hepatitis B, varicella, and H influenza have not been published. The safety of administering toxoids and inactivated vaccines in this population is well documented. In contrast, morbidity must be expected if live attenuated vaccines (oral polio vaccine, attenuated measles vaccine or attenuated varicella vaccine) are administered to children receiving anti-cancer therapy. The risks of using live vaccines should be measured against demonstrable benefits in any vaccine program. The response to initial or booster immunizations against tetanus and diphtheria are similar to those in healthy children. For all other immunizations reviewed, responsiveness is diminished during periods of chemotherapy, more strikingly in children treated for leukemia than for solid tumors. Antibody responses to these vaccines range from slightly blunted (in the case of H influenza B) to marginal (influenza) or completely useless (pneumococcus and hepatitis B in children treated for leukemia).
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PMID:Active immunization of children with leukemia and other malignancies. 847 77

Cancer is a multifactorial and multistage process, the exact mechanisms of which are still only partially known. However, even in the absence of a complete understanding of the process of carcinogenesis, we have been able to identify several factors which modify the risk of tumour development in humans. These include both endogenous and environmental factors, ranging from exposure to a single identified chemical to the occupations we follow in order to make our living. Cancer prevention strategies may differ in different parts of the world. In Europe, lung cancer is responsible for about one fourth of all cancer deaths and most of it could be prevented by eliminating tobacco smoking. Other exposures that can be controlled include occupational exposures to agents known to cause cancer at sites such as lung, bladder, paranasal sinuses, leukaemia, lymphoma and liver, as well as exposure to sunlight, known to be associated with both non-melanocytic and melanocytic skin cancer. Liver cancer is a common cancer in other regions of the world where hepatitis B virus (HBV) infection is endemic; in these areas, fungal contamination of food is also common. While immunization against HBV may be the method of choice in the long run, reduction of exposure to aflatoxins might be a more useful intermediate goal in primary prevention because of the strong interaction between hepatitis B and aflatoxin exposure on liver cancer risk. To date, few chemical agents have been proved to be of etiological relevance to cancer in humans at sites such as the breast (with the exception of oestrogenic hormones), ovary, colon-rectum and prostate.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Cancer etiology: agents causally associated with human cancer. 847 88

Chronic hepatitis B virus (HBV) infection is still a major cause of liver disease for which no definite therapy is available. We describe here a hepatitis B surface antigen (HBsAg) carrier patient with active viral replication (HBV DNA positive) who was treated for leukemia by bone marrow transplantation (BMT) from an HBV immune donor. Following BMT from the antibody to hepatitis B core antigen (anti-HBc) positive/anti-HBs positive bone marrow donor, immune reconstitution of the recipient's bone marrow resulted in clearance of the circulating HBsAg, as well as HBV DNA. The patient acquired immunity against HBV, which lasted for more than 8 months posttransplantation. Therefore, this report provides evidence that adoptive transfer of specific immunity against HBV through allogeneic BMT may lead to clearance of persistent HBV infection. Furthermore, the data support the hypothesis that the HBsAg carrier state is most probably the result of an inefficient immune response against HBV, implying that clearance of HBV may be facilitated by adoptive cellular immunotherapy.
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PMID:Ablation of persistent hepatitis B by bone marrow transplantation from a hepatitis B-immune donor. 850 Jul 41

Selection of an optimal promoter is necessary for efficient expression of foreign genes with vaccinia virus. Since a variety of powerful (homologous) vaccinia virus promoters and foreign (heterologous) promoter systems have been described for use in vaccinia, we have addressed the question of whether a general rule exists that allows the prediction of the optimal promoter/gene combination. We have compared the expression properties of four secreted proteins, the human blood clotting factor IX (FIX), the human blood glycoprotein Protein S (ProtS), the human von Willebrand factor (vWF), and the Hepatitis B virus (HBV) middle surface glycoprotein preS2, with proteins that were reported not to be secreted, the HBV large surface glycoprotein preS1 and the murine leukemia virus (MuLV) BM-5 Eco gag protein. In addition, we have included in our study an internal control protein, the vaccinia virus p11 protein, to monitor possible side effects of the promoter system used. Genes encoding the foreign proteins were placed either under control of a synthetic vaccinia virus early/late promoter (selP) or under control of the bacteriophage T7 promoter (T7/emc system). The secreted proteins were more efficiently expressed when fused to the homologous promoter. Direct comparison of the two promoters indicated that the expression level ranged between 1.4 (ProtS) and 3.9 (FIX)-fold higher with the selP than with the T7 promoter. In contrast, the cell-associated HBV preS1 was more efficiently expressed under the T7 promoter and the MuLV BM-5 Eco gag polypeptide was expressed equally well from both promoters. These data indicate that a careful prediction of optimal promoter/foreign gene combinations for the vaccinia virus expression system is possible. The choice of the optimal promoter/expression system is based on a simple classification scheme, discriminating secreted and nonsecreted proteins.
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PMID:Requirements for optimal expression of secreted and nonsecreted recombinant proteins in vaccinia virus systems. 853 47

Clearance of hepatitis B virus (HBV) infection requires an effective T-cell-dependent humoral response that is often defective in HBV carriers and in immunosuppressed patients. We have shown in mice and humans that bone marrow (BM)-derived memory cells, capable of producing antibodies to the HBV envelope and nucleocapsid antigens, are transferable from BM donors (BMD) to their recipients. BMD BALB/c mice were immunized with recombinant HBV surface antigen (HBsAg), and BM from anti-HBs-positive donors was transplanted to irradiated recipient mice, who seroconverted to anti-HBs within 30 days of bone marrow transplantation (BMT), and responded to booster vaccination. In a similar manner, 19/26 human BM recipients, who received their HLA-matched BM from BMDs immunized once with HBsAg, seroconverted within several weeks after BMT. Antibodies to HBsAg were also observed in 3 recipients of peripheral blood lymphocytes (PBL) obtained from HLA-matched immunized human donors. Finally, clearance of HBsAg and HBV DNA was observed in an HBsAg carrier with leukemia who received BMT from his HLA-matched anti-HBc+/anti-HBs+ brother. These results indicate that adoptive transfer of immunity to HBV may be achieved through immunization of BM or PBL donors against HBV.
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PMID:Immunization against hepatitis B through adoptive transfer of immunity. 866 23

The efficacy of 3 schemes of passive and active prevention of HBV infection was evaluated in 47 children with haematologic proliferative diseases. Twenty-six children suffering from leukemia (group I) received passive immunisation (hepatitis B immunoglobulin) in six week intervals during intensive chemotherapy and were vaccinated on maintenance therapy. Thirteen children with Hodgkin or B-non-Hodgkin lymphoma (group II) received active immunisation from the beginning of intensive chemotherapy with two doses of immunoglobulin. Eight children who had completed their therapy (group III) were vaccinated only. Among children who completed vaccinations, 5/8 in group I, 4/7 in group II and 5/5 in group III produced protective anti-HBs levels. Passive/active prophylaxis was successful in most patients suffering from neoplastic diseases and reduced the endemy of HBV infection in our department from 43.3% to 2.56% infected subjects. Among 7 patients vaccinated from the beginning of treatment (group II), 4 of them produced protective levels of anti,-HBs, despite intensive chemotherapy.
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PMID:[Efficacy of passive and active immunization against HBV infection in children with neoplastic diseases]. 869 93

Virus-associated human cancers provide unique opportunities for preventive strategies. The role of human papilloma viruses (HPV 16 and 18), hepatitis B virus (HBV), Epstein-Barr herpes virus (EBV), and retroviruses (human immunodeficiency virus [HIV] and human T-cell leukemia/lymphoma virus [HTLV]) in the development of common carcinomas and lymphomas represents a major cancer threat, particularly among individuals residing in developing countries, which account for 80% of the world's population. Even though these viruses are not the sole etiological agents of these cancers (as would be the case for infectious diseases), different approaches can be implemented to significantly decrease the incidence of virus-associated malignancies. The first approach is vaccination, which is available for HBV and possibly soon for EBV. The long delay between primary viral infection and development of associated tumors as well as the cost involved with administering vaccinations detracts from the feasibility of such an approach within developing countries. The second approach is to increase efforts to detect pre-cancerous lesions or early tumors using immunovirological means. This would allow early diagnosis and better treatment. The third strategy is linked to the existence of disease susceptibility genes, and suggests that counseling be provided for individuals carrying these genes to encourage them to modify their lifestyles and other conditions associated with increased cancer risks (predictive oncology). Specific recommendations include: a) increase international studies that explore the causes of the large variations in prevalence of common cancers throughout the world; b) conduct interdisciplinary studies involving laboratory investigation and social sciences, which may suggest hypotheses that may then be tested experimentally; and c) promote more preventive and health enhancement strategies in addition to curative and replacement therapies.
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PMID:Viruses and human cancers: challenges for preventive strategies. 874 97


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