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ABSTRACT: Ethanol and anesthetic drugs trigger neuroapoptosis in the developing mouse brain. Recently, it was found that ethanol-induced neuroapoptosis is preceded by suppressed phosphorylation of extracellular signal-regulated protein kinase (ERK), and lithium counteracts both the phosphorylated ERK suppressant action and ethanol-induced neuroapoptosis. The current study was undertaken to address the following questions. (1) Do ketamine and propofol mimic ethanol in suppressing ERK phosphorylation? (2) If they do, does lithium prevent this suppressant action and also prevent these anesthetic drugs from triggering neuroapoptosis?
Postnatal day 5 mice were treated with propofol, ketamine, lithium, a combination of propofol or ketamine with lithium or saline, and their brains were prepared for Western blot analysis or histology. For Western blot, cytosolic lysates of caudate putamen were analyzed for expression of phosphorylated ERK and phosphorylated serine/threonine-specific protein kinase. For histology, brains were stained immunohistochemically with antibodies to activated caspase-3, and the density of activated caspase-3 positive cells was determined.
Ketamine and propofol suppressed phosphorylated ERK, and lithium counteracted both the phosphorylated ERK suppressant action and neuroapoptotic action of these anesthetic drugs.
If further testing finds lithium to be safe for use in pediatric/obstetric medicine, administration of a single dose of lithium before anesthesia induction may be a suitable means of mitigating the risk of anesthesia-induced developmental neuroapoptosis.
Anesthesiology 05/2009; 110(4):862-8. · 5.36 Impact Factor
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ABSTRACT: Transient exposure of immature animals during the brain growth spurt period to ethanol triggers neuroapoptosis in the developing brain. Here we report that lithium, when administered in a single, well-tolerated dose to infant mice, suppresses spontaneous neuroapoptosis that occurs naturally in the developing brain, and prevents ethanol from triggering neuroapoptosis. To explore lithium's mechanism of action, we focused on kinase signaling systems (ERK, Akt, JNK) that are believed to play a regulatory role in cell survival, and found that very rapidly after ethanol administration there is a suppression of ERK phosphorylation, and that lithium stimulates ERK phosphorylation and prevents ethanol from suppressing this phosphorylation process. Ethanol also suppressed pAKT, but lithium did not counteract this effect. We also found that ethanol activates the JNK system, but this cannot explain the neurotoxic action of ethanol, because JNK activation did not occur in the same neuronal populations that are killed by ethanol.
Neurobiology of Disease 07/2008; 31(3):355-60. · 5.40 Impact Factor
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ABSTRACT: Drugs that suppress neuronal activity, including general anesthetics used in pediatric and obstetric medicine, trigger neuroapoptosis in the developing rodent brain. Exposure of infant rats for 6 hours to a combination of anesthetic drugs (midazolam, nitrous oxide, isoflurane) reportedly causes widespread apoptotic neurodegeneration, followed by lifelong cognitive deficits. Isoflurane, the dominant ingredient in this triple cocktail, has not been evaluated individually for apoptogenic potential. It was recently reported that (1) the minimum alveolar concentration (MAC) for anesthetizing infant mice with isoflurane is 2.26%, and; (2) that infant mice, without assisted respiration, maintain normal arterial oxygen values but become hypoglycemic when exposed to isoflurane 3% for 30 minutes, then 1.8% for 1 hour (1.46 MAC-hours). In the present experiments, infant mice were exposed to isoflurane at various sub-MAC concentrations and durations, and the brains were evaluated quantitatively 5 hours after initiation of anesthesia exposure to determine the number of neuronal profiles undergoing apoptosis. Blood glucose values were also determined under each of these conditions. All conditions tested (isoflurane at 0.75% for 4 h, 1.5% for 2 h, 2.0% for 1 h) triggered a statistically significant increase in neuroapoptosis compared with the rate of spontaneous apoptosis in littermate controls. Blood glucose determinations ruled out hypoglycemia as a potential cause of the brain damage. It is concluded that exposure to sub-MAC concentrations of isoflurane for one or more hours triggers neuroapoptosis in the infant mouse brain. These findings are consistent with other recent evidence demonstrating that brief exposure to ethanol, ketamine, or midazolam triggers neuroapoptosis in the developing mouse brain.
Journal of Neurosurgical Anesthesiology 02/2008; 20(1):21-8. · 2.23 Impact Factor
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Stephen A Johnson
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ABSTRACT: Waldenström's macroglobulinemia is a distinct disorder characterized by a monoclonal immunoglobulin M paraprotein and morphological evidence of lymphoplasmacytic lymphoma. It is relatively rare, accounting for approximately 2% of all hematological malignancies. The aim of treatment for patients with Waldenström's macroglobulinemia should be to improve the quality and duration of life with minimal side effects in the most cost-effective manner. It is not yet clear if achievement of a complete remission confers clinical benefit and it is possible that prolonging therapy to maximal response may increase toxicity without extra benefit. Plasma exchange is indicated for the acute management of patients with severe problems due to a circulating paraprotein. There are no comparative data but alkylating agent-based treatments, combination therapy or purine analogs are all suitable choices for the initial therapy of patients requiring treatment. In younger patients, in whom high-dose treatment is contemplated, there is a role for the use of rituximab; however, it should be administered with caution in patients with high levels of immunoglobulin M paraprotein or signs of hyperviscosity because of the risk of 'flare' in the paraprotein level and consequent adverse clinical events.
Expert Review of Anti-infective Therapy 04/2006; 6(3):329-34. · 2.65 Impact Factor
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ABSTRACT: The WM1 study is a prospective randomized open-label study that includes patients with previously untreated Waldenstrom's macroglobulinemia (WM), splenic lymphoma with villous lymphocytes (SLVL), and nonimmunoglobulin (Ig) M lymphoplasmacytic lymphoma (LPL) who have an indication for treatment. At registration, patients are categorized as having WM, SLVL, or LPL, and these cohorts are to be analyzed separately. The aim of the study is to compare the efficacy of oral chlorambucil at a dose of 8 mg/m(2) (6 mg/m(2) for those > 75 years of age) for 10 days every 28 days to a maximum of 12 cycles with oral or intravenous (I.V.) fludarabine at a dose of 40 mg/m(2) orally or 25 mg/m(2) I.V. (30 mg/m(2)orally or 20 mg/m(2)I.V. for those > 75 years of age) for 5 days every 28 days to a maximum of 6 cycles. Primary endpoints are response to therapy and duration of response; secondary endpoints are improvement in hematologic parameters, toxicity of therapy, quality of life, and survival. To detect a difference in response rate of patients with WM of 15%, assuming that the overall response rates will be 50% to chlorambucil and 65% to fludarabine, with a power of 80%, requires the sample size of each group to be 183, indicating the need for collaboration among a number of national investigator groups. As of February 2005, accrual to the study stands at 143. Registration, randomization, and data collection are entirely Internet-based (www.waldenstroms.org), and the study is organized by an international collaboration, with a planned interim analysis and an external data monitoring committee.
Clinical lymphoma 03/2005; 5(4):294-7. · 3.11 Impact Factor
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Stephen A Johnson
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ABSTRACT: After initial efforts using fludarabine as a single agent in the treatment of acute leukemia, its activity at lower and safer doses was demonstrated in chronic lymphocytic leukemia (CLL) patients who were refractory or had relapsed from traditional chemotherapies, representing a highly effective therapy for this condition. Fludarabine was also rapidly shown to be beneficial as first-line therapy in CLL. There is now considerable evidence that fludarabine is an effective agent in non-Hodgkin's lymphoma and in combination therapy for acute myeloid leukemia. Further, good responses are achieved when fludarabine-based approaches are used as conditioning regimens prior to transplantation procedures. The actions of fludarabine are not restricted to these settings and its potential role in the treatment of a range of uncommon T- and B-cell lymphoid malignancies is slowly emerging. This review will focus on the characteristics and treatment options for two B-cell disorders, mantle cell lymphoma and Waldenström's macroglobulinemia, with emphasis on the clinical activity of fludarabine. Additionally, the advantages of using fludarabine-containing regimens for a range of other lymphoproliferative conditions will also be discussed. These include B-cell neoplasms such as the CLL variant prolymphocytic leukemia, hairy cell leukemia and mucosa-associated lymphoid tissue-derived lymphomas; the T-cell disorders cutaneous T-cell lymphoma, angioimmunoblastic lymphadenopathy and other rarer T-cell diseases; and aggressive variants of non-Hodgkin's lymphoma including Richter's syndrome.
The Hematology Journal 02/2004; 5 Suppl 1:S50-61. · 1.86 Impact Factor
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Stephen A Johnson
Reviews in Clinical and Experimental Hematology 01/2003; 6(4):421-34; discussion 449-50.
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ABSTRACT: Transient exposure of immature animals during the brain growth spurt period to ethanol triggers neuroapoptosis in the developing brain. Here we report that lithium, when administered in a single, well-tolerated dose to infant mice, suppresses spontaneous neuroapoptosis that occurs naturally in the developing brain, and prevents ethanol from triggering neuroapoptosis. To explore lithium's mechanism of action, we focused on kinase signaling systems (ERK, Akt, JNK) that are believed to play a regulatory role in cell survival, and found that very rapidly after ethanol administration there is a suppression of ERK phosphorylation, and that lithium stimulates ERK phosphorylation and prevents ethanol from suppressing this phosphorylation process. Ethanol also suppressed pAKT, but lithium did not counteract this effect. We also found that ethanol activates the JNK system, but this cannot explain the neurotoxic action of ethanol, because JNK activation did not occur in the same neuronal populations that are killed by ethanol.
Neurobiology of Disease.
