Reframing manuscript rejection.
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Manuscripts as Topic↗
Biomedical subjects
L J Cohen
Publications and source records attributed to L J Cohen.
Meeting the challenge of AIDS: caring for the providers.
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Acquired Immunodeficiency Syndrome↗
Synergistic antiviral effect of PEG-asparaginase (ONCASPAR), with protease inhibitor alone and in combination with RT inhibitors against HIV-1 infected T-cells: a model of HIV-1-induced T-cell lymphoma.
We evaluated the anti-HIV-1 activity of the T-cell-specific protein inhibitor PEG-asparaginase (PEG-ASNase) in human HIV-1-infected T-cells. We further examined the drug synergism between PEG-ASNase and the protease inhibitor Saquinavir (SAQ), both alone and in combination with nucleoside analog reverse transcriptase inhibitors (NRTI). Our drug synergism studies served as a model for an HIV-induced T-cell lymphoma. Phytohemagglutinin [PHA(+)] stimulated T-cells were infected with HIV-1 and then treated with one or more drugs 90 minutes from the viral exposure. To measure inhibition of viral replication, we examined HIV-1 RT and HIV-1 RNA in the supernatant and intracellularly on day 7 post-infection and drug treatment. Last, we examined the effect of administering drugs immediately after HIV-1 infection of T-cells to simulate treatment after an accidental exposure to the virus. PEG-ASNase, even when used alone, has anti-HIV-1 activity in PHA(+)-stimulated T-cells due to inhibition of protein synthesis. When the drug was used with SAQ, the combination was synergistic in inhibiting HIV-1 RT and RNA in the supernatant and intracellularly by 2.5 log10 in comparison with controls. PEG-ASNase and SAQ were even more effective in inhibiting HIV-1 replication when combined with the NRTI inhibitors azidothymidine (AZT) and (-)-beta-2',3'-dideoxy-3'-thiacytidine (3TC, lamivudine). The addition of ribonucleotide reductase inhibitor, 2-methyl-1H-isoindole-1,3-dione (MISID), further potentiated the antiviral effect of the regimen. HIV-1 RT and RNA analyses showed that the administration of the PEG-ASNase + SAQ drug combination immediately following exposure to HIV-1 completely inhibited the infection of T-cells in our in vitro T-cell model. From these results we conclude that PEG-ASNase is a valuable T-cell-specific protein inhibitor against HIV-1 infection, when used singly or in combination with a protease inhibitor, an RT inhibitor and an RR inhibitor. Since PEG-ASNase is a drug of choice for the treatment of T-cell lymphomas, a combination regimen containing PEG-ASNase could be very effective in the treatment of HIV-1-induced T-cell lymphoma and possibly AIDS. Future studies are needed in HIV-infected and/or HIV-induced T-cell lymphoma patients to investigate these findings.
Antineoplastic Agents↗
A question of civil rights.
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Civil Rights↗
Risperidone.
Risperidone, a benzisoxazole derivative, is a novel antipsychotic agent that has an extremely strong binding affinity for serotonin 5-HT2 receptors, a strong binding affinity for dopamine D2 receptors, and a high affinity for alpha 1- and alpha 2-adrenergic receptors and histamine H1 receptors. Its affinity for serotonin receptors is approximately 200 times greater than that of haloperidol, and its dopamine antagonistic potency is comparable to that of haloperidol. Its major metabolite, 9-hydroxyrisperidone, has similar pharmacologic activity, and thus the parent compound and metabolite form the active antipsychotic moiety. Clinical trials demonstrate that risperidone is an effective antipsychotic agent that improves negative as well as positive symptoms of schizophrenia. At recommended dosages, the frequency of extrapyramidal side effects is no greater than that seen with placebo. The drug appears to be an advance in the treatment of psychoses.
Antipsychotic Agents↗
Rational drug use in the treatment of depression.
New drugs are being developed for the management of depression in response to the growing awareness of the prevalence and disability associated with the disorder and the need for agents with improved side effect profiles. All antidepressants are equally effective for treating uncomplicated unipolar depression without psychotic features. For patients with atypical depression with prominent anxiety, agitation, sleep loss, and irritability, monoamine oxidase inhibitors are the first choice. Data are accumulating supporting the efficacy of selective serotonin reuptake inhibitors (SSRIs) in these depressive subtypes. Factors to consider when choosing an antidepressant include spectrum of adverse effects, long-term tolerability, dosing schedule, clinically significant drug interactions, underlying medical conditions, earlier response to therapy, and pharmacoeconomics. Based on these criteria, it is suggested that a trial with the SSRIs be attempted first. Venlafaxine and nefazodone are newer agents with mechanisms of action that have advantages over tricyclic antidepressants and monoamine oxidase inhibitors. Choosing a drug that is effective, tolerable, and convenient will improve the likelihood of achieving and maintaining a full remission. It will also decrease the morbidity and mortality of this very treatable disease.
Antidepressive Agents↗
Increased p21/WAF-1 and p53 protein levels following sequential three drug combination regimen of fludarabine, cytarabine and docetaxel induces apoptosis in human leukemia cells.
Combinations of nucleoside analog drugs, such as F-araA and ara-C, combined with Topoisomerase II inhibitors, such as anthracyclines, are synergistic against human leukemic T-cells and induce apoptotic cell death. Similarly, nucleoside analog drugs followed by mitotic inhibitors also have a synergistic effect. Sequence specific combinations of F-araA followed by ara-C and Taxotere (docetaxel) in CEM/0 cells showed a 2- to 3-fold synergism over the two drug (F-araA + ara-C) combinations and 2- to 4-fold synergism over Taxotere alone. This synergism was evident due to enhanced cellular apoptosis. In the CEM/ara-C/7A cell line, which is partially resistant to ara-C, the synergy observed with the triple drug combination was 9-fold greater than the F-araA plus araC combination, and 3-fold greater than Taxotere alone, making this three-drug regimen collaterally sensitive to ara-C. This study describes the mechanisms of the synergistic effect in regards to apoptosis achieved by three-drug regimens comprised of two nucleoside analog drugs and a mitotic inhibitor in comparison with the combination of two nucleotide analog drugs. The study also demonstrates that the possible biochemical mechanism of cellular toxicity and drug synergism is attributed to induction of apoptosis following drug treatment and the onset of the apoptotic cascade is primarily regulated by p21/WAF-I, which is transcriptionally activated by p53 following DNA damage. The anti-apoptotic protein, bcl-2, seemed to have no effect in inhibiting apoptosis following treatment with the two or three drug regimens in this in vitro leukemia model. The three-drug combination induced greater cellular apoptosis than the two-drug combination or Taxotere monotherapy. We conclude that the greater drug synergism observed in human leukemic cells, sensitive or resistant to ara-C, by Fludarabine + ara-C + Taxotere can be explained by the greater oligonucleosomal DNA fragmentation indicative of increased cellular apoptosis. The mechanism of this increased cytotoxic action is due to the upregulation of p53 and p21/WAF-1 with a down regulation of bcl-2. These studies are encouraging, and testing this three drug regimen in a clinical setting may result in improved antileukemic therapies.
Apoptosis↗