Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0024530 (malaria)
 44,886 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The use of liposomes has recently been the subject of considerable attention as a promising and versatile approach to drug delivery. Particularly intriguing is the possibility of targeting liposomes to specific areas of the body such as tumors or sites of inflammation or parasitic invasion for either local accumulation or release of associated drugs. This review focuses mainly on recent in vivo work having clinical potential. An extensive discussion of liposome preparation and entrapment of drugs for controlled release in vivo is also included. The stability of liposomes in biological fluids is a major problem. The mode of administration, either intraperitoneal, subcutaneous, local, oral, or respiratory, is closely related to the life of the liposomes in vivo. Following in vivo administration the lifetime of a liposome is critically dependent on its composition, size, and charge. Liposome toxicity appears to be minimal, but should be considered when administering liposomes to patients. Tissues such as the liver, spleen, and lungs, because of macrophage ingestion of liposomes, become potential sites of drug toxicity. The use of liposomes to deliver antiparasitic drugs in the treatment of malaria and leishmaniasis is promoting; so it is the use of surfactant-carrying liposomes in the treatment of respiratory distress syndrome in premature babies. Recent cancer studies utilizing liposomes both in vivo and in vitro have shown promise. In tumor-bearing animals a liposome drug delivery system has caused a regression, delayed tumor growth, and increased survival time. Although the clinical use of liposomes is only in its infancy, its potential in future therapy appears promising.
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PMID:Clinical prospects for liposomes. 704 23

Liposomes have been used therapeutically to deliver drugs to certain anatomical sites. The use of liposomes to deliver antigens, although not a new concept, has received less attention. At least two vaccines of nearly identical liposome base composition to our vaccines have been tested in humans. A malaria vaccine study showed that the liposomal preparation is quite safe: reaction profiles of volunteers receiving the vaccine demonstrated little reactivity and virtually no pyrogenicity (14). The concentration of MPLA in the vaccine was substantially higher (nearly 50,000 times) than the pyrogenic dose of free lipid A. The same vaccine, but different antigen (gp120, an HIV protein), was tested in volunteers and had the same lack of toxicity (27). In both studies, antibodies and cytotoxic cells specific for the respective antigens were produced. We have several subunit vaccines under development for infectious diseases (gram negative sepsis, fungal infections, protozoan infections), metabolic disorders (hypercholesterolemia, diabetic retinopathy, macular degeneration), and neoplastic diseases (multi-drug resistant cancer, primary and metastatic tumors, and angiogenic hyperproliferative disorders). In each case, one or more antigens were identified that might be useful in immunologic control of biologic proliferation (i.e., pathogen or tumor growth, rise in serum cholesterol, growth of blood vessels). We anticipate that at least one of these vaccines will be ready for testing in humans in the next calendar year.
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PMID:Liposomal vaccines. 864 17

beta Androstenes steroid up-regulates immunity to increase resistance against lethal infection and lethal radiation, and mediates a rapid recovery of hematopoietic precursor cells after radiation injury. beta Androstenetriol increases the levels of the TH(1) cytokines, IL-2, IL-3, IFN gamma and counteracts hydrocortisone mediated immune suppression. In contrast, 17 alpha androstenediol inhibits proliferation and mediates apoptosis in tumor cells of murine and human origin. Its epimer 17beta androstenediol does not. The antiproliferative functions of 17 alpha androstenediol are not dependent on either the estrogen or androgen receptors. Our findings show that beta androstenes and analogs protect the host from lethal infection by DNA or RNA viruses such as, herpesvirus type 2, coxsackievirus B4, influenza, and arthropod borne viruses. These androstenes also protected the host from lethal bacterial infections by Enterococcus faecalis, Pseudomonas aeruginosa, and Klebsiella pneumonia and from parasites infections, i.e. Cryptosporidium parvum, and malaria. In vivo, the level of potency follows the order: dehydroepiandrosterone<<<androstenediol<androstenetriol with the latter being up to one hundred thousand times more potent in protecting the host from infections than the first. In vitro, their effects are also dramatically different from one another with only beta androstenetriol potentiating the cellular response by increasing lymphocyte activation and counteracting hydrocortisone immune-suppressive activity. Conceptually, the androstenes form a new and different subclass of steroid hormones with unique physiological properties. Following host injury, the balance between the epimers and isomers is a determining factor in the overall regulation of hematopoiesis, TH(l)/TH(2) balance, and host resistance to infections and tumor growth.
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PMID:Immune up-regulation and tumor apoptosis by androstene steroids. 1239 92

Artesunate (ART) is a derivative of artemisinin, the active principle of the Chinese herb Artemisia annua L. Artesunate is approved for the treatment of multidrug-resistant malaria and has an excellent safety profile. It has been shown that Artesunate, apart from its anti-malarial activity, has cytotoxic effects on a number of human cancer cell lines, including leukemia, colon cancer and melanoma. We report on the first long-term treatment of two cancer patients with ART in combination with standard chemotherapy. These patients with metastatic uveal melanoma were treated on a compassionate-use basis, after standard chemotherapy alone was ineffective in stopping tumor growth. The therapy-regimen was well tolerated with no additional side effects other than those caused by standard chemotherapy alone. One patient experienced a temporary response after the addition of ART to Fotemustine while the disease was progressing under therapy with Fotemustine alone. The second patient first experienced a stabilization of the disease after the addition of ART to Dacarbazine, followed by objective regressions of splenic and lung metastases. This patient is still alive 47 months after first diagnosis of stage IV uveal melanoma, a situation with a median survival of 2-5 months. Despite the small number of treated patients, ART might be a promising adjuvant drug for the treatment of melanoma and possibly other tumors in combination with standard chemotherapy. Its good tolerability and lack of serious side effects will facilitate prospective randomized trials in the near future.
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PMID:Artesunate in the treatment of metastatic uveal melanoma--first experiences. 1627 63

The Duffy antigen/receptor for chemokines (DARC) is a promiscuous chemokine receptor that binds to members of the CXC chemokine family possessing angiogenic properties. The DARC is expressed on erythrocytes and endothelial cells and is required for Plasmodium vivax infection of erythrocytes. Approximately 70% of African-Americans lack erythrocyte expression of the DARC as a genetic mechanism of protection against malaria infection. African-American men have a 60% greater incidence of prostate cancer and a 2-fold higher mortality rate than Caucasian men. Using a transgenic model of prostate cancer with DARC-deficient mice, we tested the hypothesis that lack of DARC expression on erythrocytes contributes to enhanced prostate tumor growth. In vitro, erythrocytes from wild-type mice but not DARC-deficient mice cleared angiogenic chemokines produced by prostate cancer cells and reduced endothelial cell chemotaxis. In vivo, tumors from DARC-deficient mice had higher intra-tumor concentrations of angiogenic chemokines, increased tumor vessel density, and greatly augmented prostate tumor growth. The data suggest that the DARC functions to clear angiogenic CXC chemokines from the prostate tumor microcirculation and that the lack of erythroid DARC, as occurs in the majority of African-Americans, may be a contributing factor to the increased mortality to prostate cancer in this population.
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PMID:The Duffy antigen/receptor for chemokines (DARC) regulates prostate tumor growth. 1639 68

The number of physical conditions and chemical agents induce accumulation of misfolded proteins creating proteotoxic stress. This leads to activation of adaptive pro-survival pathway, known as heat shock response (HSR), resulting in expression of additional chaperones. Several cancer treatment approaches, such as proteasome inhibitor Bortezomib and hsp90 inhibitor geldanamycin, involve activation of proteotoxic stress. Low efficacy of these therapies is likely due to the protective effects of HSR induced in treated cells, making this pathway an attractive target for pharmacological suppression. We found that the anti-malaria drugs quinacrine (QC) and emetine prevented HSR in cancer cells, as judged by induction of hsp70 expression. As opposed to emetine, which inhibited general translation, QC did not affect protein synthesis, but rather suppressed inducible HSF1-dependent transcription of the hsp70 gene in a relatively selective manner. The treatment of tumor cells in vitro with a combination of non-toxic concentrations of QC and proteotoxic stress inducers resulted in rapid induction of apoptosis. The effect was similar if QC was substituted by siRNA against hsp70, suggesting that the HSR inhibitory activity of QC was responsible for cell sensitization to proteotoxic stress inducers. QC was also found to enhance the antitumor efficacy of proteotoxic stress inducers in vivo: combinatorial treatment with 17-DMAG + QC resulted in suppression of tumor growth in two mouse syngeneic models. These results reveal that QC is an inhibitor of HSF1-mediated HSR. As such, this compound has significant clinical potential as an adjuvant in therapeutic strategies aimed at exploiting the cytotoxic potential of proteotoxic stress.
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PMID:Anti-malaria drug blocks proteotoxic stress response: anti-cancer implications. 2006 96

Chitooligosaccharides (CHOS) are homo- or heterooligomers of N-acetylglucosamine and D-glucosamine. CHOS can be produced using chitin or chitosan as a starting material, using enzymatic conversions, chemical methods or combinations thereof. Production of well-defined CHOS-mixtures, or even pure CHOS, is of great interest since these oligosaccharides are thought to have several interesting bioactivities. Understanding the mechanisms underlying these bioactivities is of major importance. However, so far in-depth knowledge on the mode-of-action of CHOS is scarce, one major reason being that most published studies are done with badly characterized heterogeneous mixtures of CHOS. Production of CHOS that are well-defined in terms of length, degree of N-acetylation, and sequence is not straightforward. Here we provide an overview of techniques that may be used to produce and characterize reasonably well-defined CHOS fractions. We also present possible medical applications of CHOS, including tumor growth inhibition and inhibition of T(H)2-induced inflammation in asthma, as well as use as a bone-strengthener in osteoporosis, a vector for gene delivery, an antibacterial agent, an antifungal agent, an anti-malaria agent, or a hemostatic agent in wound-dressings. By using well-defined CHOS-mixtures it will become possible to obtain a better understanding of the mechanisms underlying these bioactivities.
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PMID:Production of chitooligosaccharides and their potential applications in medicine. 2055 85

As an evolutionary response to prevent malaria infection, most Africans do not express the Duffy Antigen/Receptor for Chemokines (DARC) on their red blood cells. Results from experimental studies suggest that DARC expression inhibits prostate-tumor growth. We tested the hypothesis that men of African descent who lack DARC expression are at increased risk of prostate cancer. A case-control study involving 81 age-matched pairs was conducted in Jamaica. Participants were interviewed to collect data, and they donated blood for determination of DARC expression. Logistic regression was used to estimate associations with prostate cancer and aggressive disease. Little or no association was observed between erythrocyte DARC expression and prostate cancer or between DARC expression and aggressive disease. These associations changed little when adjusting for other potential confounders. Our results do not support an effect of erythrocyte DARC expression on the risk or progression of prostate cancer in men of African descent.
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PMID:The Duffy Antigen/Receptor for Chemokines (DARC) and prostate-cancer risk among Jamaican men. 2059 79

Acid sensing ion channels (ASICs) are implicated in various brain functions including learning and memory and are involved in a number of neurological disorders such as pain, ischemic stroke, depression, and multiple sclerosis. We have recently defined ASICs as one of receptor targets of aromatic diamidines in neurons. Aromatic diamidines are DNA-binding agents and have long been used in the treatment of leishmaniasis, trypanosomiasis, pneumocystis pneumonia and babesiosis. Moreover, some aromatic diamidines are used as skin-care and baby products and others have potential to suppress tumor growth or to combat malaria. A large number of aromatic diamidines or analogs have been synthesized. Many efforts are being made to optimize the therapeutic spectrum of aromatic diamidines, i.e. to reduce toxicity, increase oral bioavailability and enhance their penetration of the blood-brain barrier. Aromatic diamidines therefore provide a shortcut of screening for selective ASIC inhibitors with therapeutic potential. Intriguingly nafamostat, a protease inhibitor for treating acute pancreatitis, also inhibits ASIC activities. Aromatic diamidines and nafamostat have many similarities although they belong to distinct classes of medicinal agents for curing different diseases. Here we delineate background, clinical application and drug development of aromatic diamidines that could facilitate the screening for selective ASIC inhibitors for research purposes. Further studies may lead to a drug with therapeutic value and extend the therapeutic scope of aromatic diamidines to combat neurological diseases.
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PMID:Design and screening of ASIC inhibitors based on aromatic diamidines for combating neurological disorders. 2085 10

Quinacrine has been widely explored in treatment of malaria, giardiasis, and rheumatic diseases. We find that quinacrine stabilizes p53 and induces p53-dependent and independent cell death. Treatment by quinacrine alone at concentrations of 10-20 mM for 1-2 d cannot kill hepatocellular carcinoma cells, such as HepG2, Hep3B, Huh7, which are also resistant to TRAIL. However, quinacrine renders these cells sensitive to treatment by TRAIL. Co-treatment of these cells with quinacrine and TRAIL induces overwhelming cell death within 3-4 h. Levels of DR5, a pro-apoptotic death receptor of TRAIL, are increased upon treatment with quinacrine, while levels of Mcl-1, an anti-apoptotic member of the Bcl-2 family, are decreased. While the synergistic effect of quinacrine with TRAIL appears to be in part independent of p53, knockdown of p53 in HepG2 cells by siRNA results in more cell death after treatment by quinacrine and TRAIL. The mechanism by which quinacrine sensitizes hepatocellular carcinoma cells to TRAIL and chemotherapies, and the potential for clinical application currently are being further explored. Lastly, quinacrine synergizes with chemotherapeutics, such as adriamycin, 5-FU, etoposide, CPT11, sorafenib, and gemcitabine, in killing hepatocellular carcinoma cells in vitro and the drug enhances the activity of sorafenib to delay tumor growth in vivo.
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PMID:Quinacrine sensitizes hepatocellular carcinoma cells to TRAIL and chemotherapeutic agents. 2172 12


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