Quantitative Analysis of Serum Zinc Levels in Primary Brain Tumor Patients.

Although the close relationships between most of the trace elements and tumor formation mechanisms are very well-defined, studies on some elements such as zinc are still ongoing. When examining studies on brain tumors, it was observed that studies investigating the role played by serum zinc levels on tumor etiology and prognosis have gained momentum. In this study, we investigate the relationship between different brain tumor types and serum zinc levels by quantitatively analyzing serum zinc levels in patients with primary brain tumors. In this study, we measured serum zinc levels of 33 brain tumor patients as well as 35 healthy individuals serving as a control group. Metal concentrations were measured using atomic absorption spectrophotometry. Serum zinc levels were lower in patients with primary brain tumors compared to control group (p < 0.05). Additionally, patients' serum zinc levels were significantly different according to their brain tumor types and also according to their age (p < 0.05). Our findings suggest that brain tumor patients' serum zinc levels may play a role in tumor etiology, typology, and prognosis.

Effects of donepezil on liver and kidney functions for the treatment of Alzheimer's disease.

Aim of the present study is to investigate the effects of medication with donepezil (acetylcholinesterase inhibitor) on the liver and kidney function in Alzheimer's disease (AD) and to compare the effects of donepezil medication during short (one month) and long term (six years) follow-ups. We evaluated female and male patients from Cukurova [42 AD patients; short term (5 mg/day)] and Dokuz Eylul [68 AD patients; long term (10 mg/day)] University Hospital. The results compared with the geriatric population without dementia in other words who are not in medication with donepezil. For short term evaluation all subjects underwent periodic examination with tests regarding hepatic and renal functions; firstly, before starting treatment and then repeated one month later. For long term evaluation all subjects underwent periodic examination with tests regarding hepatic and renal functions; three times at the end of each two consecutive years of treatment with donepezil. AD patients' results were also compared with 79 neurologically healthy geriatric patients without dementia who were over 65 years of age and were not receiving medication with donepezil. For this task, serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels are used to predict possible liver damage, while the blood urea nitrogen (BUN) and creatinine (CRE) levels for kidney damage. No significant difference between the groups regarding the routine control of biochemical parameters was observed in short term drug medication. In long term patients' group; the effects of two years use of donepezil on renal and hepatic function were also evaluated and levels of AST, ALT, BUN and CRE were found to be increased significantly compared to pretreatment levels. But, they remained in the reference intervals. However, levels of AST and ALT at the end of the fourth year of therapy were similar to those measured at the end of the second year, levels of BUN and CRE continuing to increase with staying below the reference limits. Functional markers obtained at the end of the sixth year of therapy were not differing from those of the fourth year. No significant difference was found during comparisons within the results of the neurologically healthy geriatric patient group. During comparisons between the two groups, measurements obtained at all-time points were significantly high in donepezil treated AD patients. We concluded that customized dosage according to hepatic and renal functions is necessary for using acetylcholinesterase inhibitor in AD patients.

A nationwide multicentre study in Turkey for establishing reference intervals of haematological parameters with novel use of a panel of whole blood.

INTRODUCTION: A nationwide multicentre study was conducted to establish well-defined reference intervals (RIs) of haematological parameters for the Turkish population in consideration of sources of variation in reference values (RVs). MATERIALS AND METHODS: K2-EDTA whole blood samples (total of 3363) were collected from 12 laboratories. Sera were also collected for measurements of iron, UIBC, TIBC, and ferritin for use in the latent abnormal values exclusion (LAVE) method. The blood samples were analysed within 2 hours in each laboratory using Cell Dyn and Ruby (Abbott), LH780 (Beckman Coulter), or XT-2000i (Sysmex). A panel of freshly prepared blood from 40 healthy volunteers was measured in common to assess any analyser-dependent bias in the measurements. The SD ratio (SDR) based on ANOVA was used to judge the need for partitioning RVs. RIs were computed by the parametric method with/without applying the LAVE method. RESULTS: Analyser-dependent bias was found for basophils (Bas), MCHC, RDW and MPV from the panel test results and thus those RIs were derived for each manufacturer. RIs were determined from all volunteers' results for WBC, neutrophils, lymphocytes, monocytes, eosinophils, MCV, MCH and platelets. Gender-specific RIs were required for RBC, haemoglobin, haematocrit, iron, UIBC and ferritin. Region-specific RIs were required for RBC, haemoglobin, haematocrit, UIBC, and TIBC. CONCLUSIONS: With the novel use of a freshly prepared blood panel, manufacturer-specific RIs' were derived for Bas, Bas%, MCHC, RDW and MPV. Regional differences in RIs were observed among the 7 regions of Turkey, which may be attributed to nutritional or environmental factors, including altitude.

Evaluation of Renal Function in Alzheimer's Disease and Geriatric Patients: Results from a Turkish Two-center Study.

BACKGROUND: Alzheimer's disease (AD) is a severe multifactorial neurodegenerative proteopathy associated with advanced age. Discrepancies in the renal function of these patients compared to geriatric patients with dementia have rarely been reported. In this study, we aimed to disclose the importance of associated renal changes for the pathogenesis of AD. METHODS: Patients with AD (n=107) and geriatric patients with dementia and without dementia (n=124) (231 patients in total) from Dokuz Eylul and Cukurova University Hospitals were enrolled in the study. We measured serum Na, K, Cl, Ca, BUN, creatinine, total protein levels and MDRD [eGFR] in all groups. RESULTS: From Izmir Center, the first study arm consisted of patients with AD dementia (n=74), and the second arm included geriatric patients with dementia (n=79). From Adana, 78 patients were recruited to the study, of which 33 were with AD and 45 were geriatric patients without dementia. When we analyzed comparatively the AD and geriatric dementia patients study arms, a statistically significant difference was observed both in the median age (p<0.001), as well as in the biochemical parameters from Izmir Center: Na (p<0.001), K (p<0.001), Cl (p<0.05), Ca (p<0.001), BUN (p<0.05), creatinine (p<0.001), total protein (p<0.001) and MDRD [eGFR] (p<0.001). However, these were not significantly different between AD and geriatric patients without dementia in the Adana group. CONCLUSIONS: Our results indicate that renal function is prone to alterations in different age groups of patients with AD. However, there is no conclusive evidence that renal function is one of the risk factors in AD.

Cell division cycle 7-kinase inhibitor PHA-767491 hydrochloride suppresses glioblastoma growth and invasiveness.

BACKGROUND: Genomic instability is a hallmark of cancer cells, and this cellular phenomenon can emerge as a result of replicative stress. It is possible to take advantage of replicative stress, and enhance it in a targeted way to fight cancer cells. One of such strategies involves targeting the cell division cycle 7-related protein kinase (CDC7), a protein with key roles in regulation of initiation of DNA replication. CDC7 overexpression is present in different cancers, and small molecule inhibitors of the CDC7 have well-documented anti-tumor effects. Here, we aimed to test the potential of CDC7 inhibition as a new strategy for glioblastoma treatment. METHODS: PHA-767491 hydrochloride was used as the CDC7 inhibitor. Two glioblastoma cell lines (U87-MG and U251-MG) and a control cell line (3T3) were used to characterize the effects of CDC7 inhibition. The effect of CDC7 inhibition on cell viability, cell proliferation, apoptosis, migration, and invasion were analyzed. In addition, real-time PCR arrays were used to identify the differentially expressed genes in response to CDC7 inhibition. RESULTS: Our results showed that CDC7 inhibition reduces glioblastoma cell viability, suppresses cell proliferation, and triggers apoptosis in glioblastoma cell lines. In addition, we determined that CDC7 inhibition also suppresses glioblastoma cell migration and invasion. To identify molecular targets of CDC7 inhibition, we used real-time PCR arrays, which showed dysregulation of several mRNAs and miRNAs. CONCLUSIONS: Taken together, our findings suggest that CDC7 inhibition is a promising strategy for treatment of glioblastoma.

Artificial Neural Network Approach in Laboratory Test Reporting: Learning Algorithms.

OBJECTIVES: In the field of laboratory medicine, minimizing errors and establishing standardization is only possible by predefined processes. The aim of this study was to build an experimental decision algorithm model open to improvement that would efficiently and rapidly evaluate the results of biochemical tests with critical values by evaluating multiple factors concurrently. METHODS: The experimental model was built by Weka software (Weka, Waikato, New Zealand) based on the artificial neural network method. Data were received from Dokuz Eylül University Central Laboratory. "Training sets" were developed for our experimental model to teach the evaluation criteria. After training the system, "test sets" developed for different conditions were used to statistically assess the validity of the model. RESULTS: After developing the decision algorithm with three iterations of training, no result was verified that was refused by the laboratory specialist. The sensitivity of the model was 91% and specificity was 100%. The estimated κ score was 0.950. CONCLUSIONS: This is the first study based on an artificial neural network to build an experimental assessment and decision algorithm model. By integrating our trained algorithm model into a laboratory information system, it may be possible to reduce employees' workload without compromising patient safety.

A Turkish 3-center study evaluation of serum folic acid and vitamin B12 levels in Alzheimer disease.

BACKGROUND/AIM: Alzheimer disease, a common proteopathy of advanced age, is characterized by cortical atrophy, neuron degeneration, neuronal loss, and accumulation of extracellular amyloid ß plaques. We aimed to investigate serum vitamin B12 and folic acid levels in Alzheimer disease and other dementia patients, as a potential screening test to detect presymptomatic Alzheimer disease in Turkish patients. MATERIALS AND METHODS: We evaluated folic acid and vitamin B12 levels in Alzheimer disease patients as well as in other dementia and geriatric patients from Ankara, Dokuz Eylül, and Çukurova university hospitals; 290 female and male geriatric subjects were enrolled. Vitamin B12 and folic acid levels were measured using Roche E170 and Beckman Coulter DXI 800 immunoassays (chemiluminescence) according to the manufacturers' guideline in all centers. RESULTS: We evaluated the results of folic acid and vitamin B12 in Alzheimer disease, other dementias and geriatric patients. No significant difference between the groups regarding the routine control of biochemical parameters was observed. CONCLUSION: Currently, serum folic and vitamin B12 levels are not diagnostically reliable tests for screening presymptomatic Alzheimer disease. However, the results may statistically be significant if we increase the sample size.

Experimental traumatic spinal cord injury.

Animal models are important to develop therapies for individuals suffering from spinal cord injuries. For this purpose, rats are commonly preferred. In sharp injury models, spinal cord is completely or incompletely cut to assess axonal regeneration. On the other hand, spinal cord is compressed or contused to mimic the human injury in blunt injury models for understanding as well as managing the secondary pathophysiologic processes following injury. Especially, contusions are thought to be biomechanically similar to vertebral fractures and/or dislocations and thus provide the most realistic experimental setting in which to test potential neuroprotective and regenerative strategies.

Erythropoietin-induced changes in brain gene expression reveal induction of synaptic plasticity genes in experimental stroke.

Erythropoietin (EPO) is a neuroprotective cytokine in models of ischemic and nervous system injury, where it reduces neuronal apoptosis and inflammatory cytokines and increases neurogenesis and angiogenesis. EPO also improves cognition in healthy volunteers and schizophrenic patients. We studied the effect of EPO administration on the gene-expression profile in the ischemic cortex of rats after cerebral ischemia at early time points (2 and 6 h). EPO treatment up-regulated genes already increased by ischemia. Hierarchical clustering and analysis of overrepresented functional categories identified genes implicated in synaptic plasticity-Arc, BDNF, Egr1, and Egr2, of which Egr2 was the most significantly regulated. Up-regulation of Arc, BDNF, Dusp5, Egr1, Egr2, Egr4, and Nr4a3 was confirmed by quantitative PCR. We investigated the up-regulation of Egr2/Krox20 further because of its role in neuronal plasticity. Its elevation by EPO was confirmed in an independent in vivo experiment of cerebral ischemia in rats. Using the rat neuroblastoma B104, we found that wild-type cells that do not express EPO receptor (EPOR) do not respond to EPO by inducing Egr2. However, EPOR-expressing B104 cells induce Egr2 early upon incubation with EPO, indicating that Egr2 induction is a direct effect of EPO and that EPOR mediates this effect. Because these changes occur in vivo before decreased inflammatory cytokines or neuronal apoptosis is evident, these findings provide a molecular mechanism for the neuroreparative effects of cytokines and suggest a mechanism of neuroprotection by which promotion of a plastic phenotype results in decreased inflammation and neuronal death.

Evaluation of the effect of acetyl L-carnitine on experimental cisplatin ototoxicity and neurotoxicity.

INTRODUCTION: Cisplatin (CDDP) is an effective and widely used chemotherapeutic agent for pediatric tumors, and ototoxicity is one of the dose-limiting side effects. OBJECTIVE: It was the aim of our study to investigate the effect of acetyl L-carnitine (ALCAR) on experimental CDDP ototoxicity by audiologic tests, histomorphologic, immunohistochemical and ultrastructural examinations and to investigate the apoptotic pathways. MATERIALS AND METHODS: Wistar albino rats (n = 28) were studied. Baseline audiological tests were performed in 4 groups: group 1, control; group 2, ALCAR; group 3, CDDP; group 4, CDDP + ALCAR-administered rats. Control audiological tests were performed on the 3rd day, and then the rats were sacrificed. Ear and brain specimens were examined by transmission electron microscopy, and caspase 3, 8 and 9 activities were investigated. RESULTS: The CDDP-administered rats showed significant auditory brainstem response threshold shifts using all stimuli (clicks, 6-kHz and 8-kHz tone burst) compared with the control groups. The CDDP + ALCAR-administered rats showed significant auditory brainstem response threshold shifts by only click stimuli compared with the control groups. In the brain, spiral ganglion and organ of Corti, ultrastructural damage was prominent in group 3; the number of TUNEL (terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling)-positive cells and caspase 3, 8 and 9 immunostaining cells was significantly high in group 3. CONCLUSION: ALCAR improves CDDP-induced auditory impairment, and also antioxidative and antiapoptotic properties of ALCAR on CDDP ototoxicity were supported by the findings.

Protective effects of acetyl-L-carnitine on cisplatin cytotoxicity and oxidative stress in neuroblastoma.

The most widely used platinum-derived drug is cisplatin in neuroblastoma (NB) chemotherapy, which is severely neurotoxic. Acetyl-L-Carnitine (ALC) is a natural occurring compound with a neuroprotective activity in several experimental paradigms. The aim of this study was to determine the effects of ALC on cisplatin induced cytotoxicity and oxidative stress in NB cells. SH-SY5Y (N-Myc negative) and KELLY (N-Myc positive) human NB cell lines were used. Cisplatin induced apoptosis was assessed by using a Cell Death Detection ELISA(PLUS) kit. Lipid peroxidation levels were determined by HPLC analysis. Glutathione levels were determined spectrophotometrically. ALC was used prophylactic or after cisplatin application. The level of cisplatin doses were determined in both type of NB cells at which 50% cell death occurred along with synchronized apoptosis induced. Prophylactic 10 and 50 micromol of ALC concentrations were decreased cisplatin induced lipid peroxidation compared to controls that normally exhibited apoptosis especially in SH-SY5Y cells. Cisplatin caused oxidative stress through decreasing glutathione levels in both cell types. ALC were effectively inhibited the increase in cisplatin induced oxidized glutathione and lipid peroxidation formation in NB cells. We suggested that prophylactic ALC would be a useful agent for cisplatin induced toxicity in NB cells.

Effect of cytotoxic agents and retinoic acid on Myc-N protein expression in neuroblastoma.

AIM: Neuroblastoma is an important pediatric tumor in which Myc-N amplification is a well-known poor prognostic indicator. It has a great diversity in clinical behavior. The effect of pharmacologic agents used in neuroblastoma treatment on Myc-N expression is still unclear. METHOD: We analyzed Myc-N expression changes by immunocytochemistry in Myc-N-positive Kelly human neuroblastoma cell line using retinoic acid and cytotoxic drugs (cisplatin, vincristine, cyclophosphamide, etoposide, and doxorubicin) and their combinations compared with control conditions. First, concentration of drugs were determined as LD50 doses. Kelly cells and drugs were incubated for 24 hours in 5% CO2, 37 degrees C in 96-well plates. Myc-N expression was scored semiquantitatively as negative, mild, moderate, or high positive. RESULTS: Myc-N amplification did not change with any agent or combination. It was higher than 20 copies in all conditions. Myc-N protein expression was high in control and doxorubicin group. It was moderate in retinoic acid, cyclophosphamide, retinoic acid combined with cyclophosphamide and retinoic acid combined with doxorubicin groups. The expression was mild in cisplatin, vincristine, etoposide, retinoic acid combined with etoposide, and retinoic acid combined with cisplatin groups. Myc-N expression was negative in retinoic acid combined with vincristine group. CONCLUSIONS: Myc-N expression is reduced with cytotoxic agents and retinoic acid in neuroblastoma although Myc-N amplification remains the same. Retinoic acid combined with vincristine is the most effective combination to reduce Myc-N expression. Our results suggest that therapeutic applications of these agents as low dose maintenance therapy might be useful.

Evaluation of the effect of acetyl L-carnitine on experimental cisplatin nephrotoxicity.

BACKGROUND/AIMS: To evaluate the protective effects of acetyl L-carnitine (ALCAR) on cisplatin-induced nephrotoxicity in rats, and to gain insights into the possible protective mechanisms of ALCAR against nephrotoxicity. METHODS: Twenty-eight Wistar rats were divided into four groups. Group 1 was administered saline only, group 2 was administered ALCAR, group 3 was administered cisplatin, and group 4 was administered ALCAR prior to cisplatin. Rats were sacrificed after 72 h of cisplatin/saline infusion. Serum creatinine and glomerular filtration rate values were obtained, and kidney samples were examined by light and electron microscopy. Apoptotic cell death and caspase-3, 8 and 9 activities were studied immunohistochemically. RESULTS: In group 4, ALCAR administration resulted in an improvement in kidney function tests. Histopathological findings confirmed the biochemical data. Whilst the fusion of the foot processes of podocytes was observed in group 3, they were intact in group 4 on electron-microscopic examination. Apoptotic cell death and caspase-3, 8 and 9 activities were also decreased in group 4 compared to group 3. CONCLUSIONS: Antioxidative, antiapoptotic and anti-inflammatory properties of ALCAR were supported by the findings that this agent improves kidney function tests and has the effects of tissue protection and inhibition of apoptosis in cisplatin-induced nephrotoxicity.

Nonerythropoietic tissue protective compounds are highly effective facilitators of wound healing.

Erythropoietin (EPO) is a type I cytokine that utilizes different receptor isoforms either to maintain hematopoiesis or protect against injuries that arise from widely diverse etiologies. EPO also facilitates healing by reducing inflammation and mobilizing endothelial progenitor cells to participate in restorative neoangiogenesis, but it is unclear which EPO receptor isoform is responsible for healing and whether this receptor use varies according to the type of wound. In the present studies carried out in the rat, we have utilized receptor-selective derivatives of EPO to determine which receptor type operates in (i) a nonischemic wound (skin punch biopsy), (ii) a permanently ischemic wound (raised musculocutaneous flap), (iii) an intermittent ischemic reperfusion wound (pressure or decubitus ulcer), or (iv) wounds complicated by infection (cecal ligation and perforation). Using these models, we demonstrate that nonerythropoietic tissue protective compounds administered immediately following injury limit wound size and accelerate eschar closure independent of wound type. Moreover, in a model of peritonitis-induced adhesions, daily administration of the nonerythropoietic derivative carbamyl-EPO (10 microg/kg-bw) was associated with significantly lower serum TNFalpha concentration, illness scores, increased survival, as well as decreased adhesion formation. These results confirm that wound healing is mediated by the tissue protective receptor isoform and argue that nonerythropoietic tissue protective molecules constitute promising new.

Nonerythropoietic, tissue-protective peptides derived from the tertiary structure of erythropoietin.

Erythropoietin (EPO), a member of the type 1 cytokine superfamily, plays a critical hormonal role regulating erythrocyte production as well as a paracrine/autocrine role in which locally produced EPO protects a wide variety of tissues from diverse injuries. Significantly, these functions are mediated by distinct receptors: hematopoiesis via the EPO receptor homodimer and tissue protection via a heterocomplex composed of the EPO receptor and CD131, the beta common receptor. In the present work, we have delimited tissue-protective domains within EPO to short peptide sequences. We demonstrate that helix B (amino acid residues 58-82) of EPO, which faces the aqueous medium when EPO is bound to the receptor homodimer, is both neuroprotective in vitro and tissue protective in vivo in a variety of models, including ischemic stroke, diabetes-induced retinal edema, and peripheral nerve trauma. Remarkably, an 11-aa peptide composed of adjacent amino acids forming the aqueous face of helix B is also tissue protective, as confirmed by its therapeutic benefit in models of ischemic stroke and renal ischemia-reperfusion. Further, this peptide simulating the aqueous surface of helix B also exhibits EPO's trophic effects by accelerating wound healing and augmenting cognitive function in rodents. As anticipated, neither helix B nor the 11-aa peptide is erythropoietic in vitro or in vivo. Thus, the tissue-protective activities of EPO are mimicked by small, nonerythropoietic peptides that simulate a portion of EPO's three-dimensional structure.

Effects of selenium supplementation on antioxidant defense and glucose homeostasis in experimental diabetes mellitus.

The objective of this study was to investigate the effects of different forms of Se supplementation on the antioxidant defense and glucose homeostasis in experimental diabetes. Sodium selenate (SS) or selenomethionine (SM) were administered (2 micromol Se kg(-1) day(-1)) via orogastric route to streptozotocine (STZ)-induced diabetic rats in addition to basal diet for 12 weeks. Glucose levels in whole blood, glutathione peroxidase (GSH-Px) activity in erythrocytes, Se and fructosamine levels in plasma were evaluated monthly. Plasma Se levels increased significantly in all diabetic groups compared to basal measurements, being more prominent in SM group [p(SM(3)/SM(0)) = 0.018]. The increase in GSH-Px activities was significant at the end of the second month in SS [p(SS(2)/SS(0)) = 0.028], whereas at the end of the third month in SM the value was lower [p(SM3/SM0) = 0.018] and the unsupplemented diabetic control (DC) groups, p(DC(3)/DC(0)) = 0.012. Glucose increased significantly only in DC group. Fructosamine increased gradually in all diabetic groups, being significant in DC and SS groups. At the end of the third month, highest fructosamine levels were observed in SS group, which were significantly higher than the SM group [p(SM/SS) = 0.010]. In conclusion, Se augmented the antioxidant defense by increasing GSH-Px activity and this effect was more prominent when Se was supplemented as SM, which exerted positive effects also on glucose homeostasis.

Carbamylated erythropoietin reduces radiosurgically-induced brain injury.

Gamma knife radiosurgery is an attractive noninvasive treatment of brain tumors and vascular malformations that minimizes collateral tissue damage. However, exposure of normal tissue to even low-dose radiation triggers a cascade of acute and chronic injury and potentially significant morbidity and mortality. Because many irradiated patients now survive for years, identifying methods to prevent radiotherapy-induced collateral tissue damage is a major focus of current research. Erythropoietin (EPO), a cytokine produced locally by many tissues in response to injury, antagonizes apoptosis, reduces inflammation, and promotes healing. Systemic administration of recombinant EPO, widely used for treatment of anemia, provides robust protection from numerous insults in a variety of tissues, including the brain. Although irradiation injury is likely sensitive to EPO, the hematopoietic activity of EPO is undesirable in this setting, increasing erythrocyte number and predisposing to thrombosis. To avoid these potential adverse effects, we developed carbamylated EPO (CEPO) which does not stimulate the bone marrow. In this study, we show that CEPO (50 microg kg(-1) intraperitoneally) improves functional outcome when administered to adult rats just before, and then once daily for 10 d after, a necrotizing dose of radiation (100 Gy) to the right striatum. Immediately following irradiation, use and reflex movements of the contralateral forelimb to vibrissae stimulation were abnormal but rapidly improved in animals receiving CEPO. Moreover, histological examination revealed that the extent of brain necrosis after 90 days was reduced by approximately 50%. These findings further extend the kinds of injury for which administration of a tissue-protective cytokine provides benefit.

Lithium-induced alterations in nucleoside triphosphate levels in human brain: a proton-decoupled 31P magnetic resonance spectroscopy study.

We examined how lithium's demonstrated effects on various cellular processes in human brain would be reflected in the (31)P magnetic resonance spectra of living human beings with respect to brain high-energy phosphate metabolites. Eight healthy volunteers received a baseline (31)P magnetic resonance spectroscopy (MRS) scan, after which they received lithium carbonate, 900 mg/day, for 14 days. Follow-up MRS scans were obtained on day 7 and on day 14. We detected a lithium-induced decrease in alpha-, beta-, gamma- and total nucleoside triphosphate NTP levels with chronic administration of lithium. On day 7, significant decreases were noted in gamma-NTP (14%) and total NTP (11%) levels. There was a trend for a decrease in beta-NTP (11%) levels. On day 14, significant decreases were noted in alpha-NTP (7%) and total NTP (8%) levels. There was a trend for a decrease in beta-NTP (16%) levels. Lithium caused a 25% reduction in inorganic phosphate (P(i)) levels on day 14. The theoretical relevance of the lithium-induced alterations on brain high-energy phosphates to the lithium-induced modifications of neuroplasticity is discussed.

Derivatives of erythropoietin that are tissue protective but not erythropoietic.

Erythropoietin (EPO) is both hematopoietic and tissue protective, putatively through interaction with different receptors. We generated receptor subtype-selective ligands allowing the separation of EPO's bioactivities at the cellular level and in animals. Carbamylated EPO (CEPO) or certain EPO mutants did not bind to the classical EPO receptor (EPOR) and did not show any hematopoietic activity in human cell signaling assays or upon chronic dosing in different animal species. Nevertheless, CEPO and various nonhematopoietic mutants were cytoprotective in vitro and conferred neuroprotection against stroke, spinal cord compression, diabetic neuropathy, and experimental autoimmune encephalomyelitis at a potency and efficacy comparable to EPO.

Asialoerythropoietin is a nonerythropoietic cytokine with broad neuroprotective activity in vivo.

Erythropoietin (EPO) is a tissue-protective cytokine preventing vascular spasm, apoptosis, and inflammatory responses. Although best known for its role in hematopoietic lineages, EPO also affects other tissues, including those of the nervous system. Enthusiasm for recombinant human erythropoietin (rhEPO) as a potential neuroprotective therapeutic must be tempered, however, by the knowledge it also enlarges circulating red cell mass and increases platelet aggregability. Here we examined whether erythropoietic and tissue-protective activities of rhEPO might be dissociated by a variation of the molecule. We demonstrate that asialoerythropoietin (asialoEPO), generated by total enzymatic desialylation of rhEPO, possesses a very short plasma half-life and is fully neuroprotective. In marked contrast with rhEPO, this molecule at doses and frequencies at which rhEPO exhibited erythropoiesis, did not increase the hematocrit of mice or rats. AsialoEPO appeared promptly within the cerebrospinal fluid after i.v. administration; intravenously administered radioiodine-labeled asialoEPO bound to neurons within the hippocampus and cortex in a pattern corresponding to the distribution of the EPO receptor. Most importantly, asialoEPO exhibits a broad spectrum of neuroprotective activities, as demonstrated in models of cerebral ischemia, spinal cord compression, and sciatic nerve crush. These data suggest that nonerythropoietic variants of rhEPO can cross the blood-brain barrier and provide neuroprotection.