Fucosylation Enhances the Efficacy of Adoptively Transferred Antigen-Specific Cytotoxic T Lymphocytes

PURPOSE

Inefficient homing of adoptively transferred cytotoxic T lymphocytes (CTLs) to tumors is a major limitation to the efficacy of adoptive cellular therapy (ACT) for cancer. However, through fucosylation, a process whereby fucosyltransferases (FT) add fucose groups to cell surface glycoproteins, this challenge may be overcome. Endogenously fucosylated CTLs and ex vivo fucosylated cord blood stem cells and regulatory T cells were shown to preferentially home to inflamed tissues and marrow. Here, we show a novel approach to enhance CTL homing to leukemic marrow and tumor tissue.

EXPERIMENTAL DESIGN

Using the enzyme FT-VII, we fucosylated CTLs that target the HLA-A2-restricted leukemia antigens CG1 and PR1, the HER2-derived breast cancer antigen E75, and the melanoma antigen gp-100. We performed in vitro homing assays to study the effects of fucosylation on CTL homing and target killing. We used in vivo mouse models to demonstrate the effects of ex vivo fucosylation on CTL antitumor activities against leukemia, breast cancer, and melanoma.

RESULTS

Our data show that fucosylation increases in vitro homing and cytotoxicity of antigen-specific CTLs. Furthermore, fucosylation enhances in vivo CTL homing to leukemic bone marrow, breast cancer, and melanoma tissue in NOD/SCID gamma (NSG) and immunocompetent mice, ultimately boosting the antitumor activity of the antigen-specific CTLs. Importantly, our work demonstrates that fucosylation does not interfere with CTL specificity.

CONCLUSIONS

Together, our data establish ex vivo CTL fucosylation as a novel approach to improving the efficacy of ACT, which may be of great value for the future of ACT for cancer.

Fucosyltransferase VII improves the function of selectin ligands on cord blood hematopoietic stem cells

Selectins and their carbohydrate ligands mediate the homing of hematopoietic stem/progenitor cells (HSPCs) to the bone marrow. We have previously shown that ex vivo fucosylation of selectin ligands on HSPCs by α1,3 fucosyltransferase VI (FUT6) leads to improved human cord blood (CB)-HSPC engraftment in non-obese diabetic (NOD)/severe combined immune deficient (SCID) mice. In the present study, we determined whether surface fucosylation with α1,3 fucosyltransferase VII (FUT7), which is primarily expressed by hematopoietic cells, improves the function of selectin ligands on CB-HSPCs in comparison with FUT6. A saturating amount of either FUT6 or FUT7, which generates comparable levels of expression of fucosylated epitopes on CB CD34(+) cells, was used for these experiments. In vitro, FUT7-treated CB CD34(+) cells exhibited greater binding to P- or E-selectin than that of FUT6-treated CB CD34(+) cells under static or physiological flow conditions. In vivo, FUT7 treatment, like FUT6, improved the early engraftment of CB CD34(+) cells in the bone marrow of sublethally irradiated NOD/SCID interleukin (IL)-2Rγ(null) (NSG) mice. FUT7 also exhibited marginally-yet statistically significant-increased engraftment at 4 and 6 weeks after transplantation. In addition, FUT7-treated CB CD34(+) cells exhibited increased homing to the bone marrow of irradiated NSG mice relative to sham-treated cells. These data indicate that FUT7 is effective at improving the function of selectin ligands on CB-HSPCs in vitro and enhancing early engraftment of treated CB-HSPCs in the bone marrow of recipients.

Circulating mononuclear progenitor cells: differential roles for subpopulations in repair of retinal vascular injury

PURPOSE

We examined effect on retinal vascular homing of exogenous CD34(+) and CD14(+) progenitor cells using mouse models of chronic (streptozotocin [STZ]-induced diabetes) and acute (ischemia-reperfusion [I/R]) ocular vascular injury.

METHODS

STZ-treated mice of short or long duration (≤4, ≥11 months) diabetes, along with age- and sex-matched controls, were given intravitreous injections of human CD34(+) and CD14(+) cells isolated from healthy or diabetic donors alone or in combination. I/R injured mice were given diabetic or nondiabetic CD34(+) cells with mesenchymal stem cells (MSCs) or diabetic CD34(+) cells manipulated by ex vivo fucosylation with ASC-101. Injected cells were localized by fluorescent immunocytochemistry, and the degree of retinal vascular colocalization quantified morphometrically. Permeability was assessed by fluorescent albumin leakage.

RESULTS

Diabetic CD14(+) cells associated with vessels to a greater degree than diabetic CD34(+) cells. Vascular permeability was reduced only by nondiabetic cells and only at the highest number of cells tested. Diabetic CD34(+) cells consistently demonstrated reduced migration. There was a 2-fold or 4-fold increase over control in the specific localization of diabetic CD34(+) cells within the vasculature when these cells were co-administered with MSCs or ex vivo fucosylated prior to injection, respectively.

CONCLUSIONS

Diabetic CD14(+) cells, unlike diabetic CD34(+) cells, retain robust homing characteristics. CD34(+) or CD14(+) subsets rather than whole bone marrow or peripheral blood cells may prove more beneficial in autologous cell therapy for diabetics. Co-administration with MSCs or ex vivo fucosylation may enhance utility of CD34(+) cells in cell therapy for diabetic ocular conditions like macular ischemia and retinal nonperfusion.

The Effect of Cyclohexyladenosine on the Penischemic Increases of Hippocampal Glutamate and Glycine in the Rabbit

We investigated the ability of N6-cyclohexyladenosine (CHA), a potent and selective agonist of the adenosine A1 receptor, to attenuate elevations of levels of extracellular hippocampal glutamate and glycine that result from episodes of transient global cerebral ischemia (TGCI). A total of 30 New Zealand white rabbits were randomly assigned to receive 0 (n = 5), 0.1 (n = 8), 1.0 (n = 6), 10 (n = 6), or 100 (n = 5) microM CHA. The drug was dissolved in artificial CSF (vehicle) and administered via a microdialysis probe placed stereotactically into the dorsal hippocampus. A second microdialysis probe placed into the contralateral hippocampus of each animal was perfused with vehicle alone. Ten minutes of TGCI was induced by neck tourniquet inflation and deliberate hypotension from 0 to 10 min. Microdialysis samples were collected as follows: every 20 min preischemia (at -80, -60, -40, -20, and 0 min); every 5 min during ischemia and in the immediate reperfusion period (at 5, 10, 15, and 20 min); and every 20 min for the remainder of the reperfusion period (at 40, 60, and 80 min). Samples were then analyzed for their concentration of glutamate and glycine by HPLC. Following 10 min of ischemia, glutamate levels increased to a peak of 3.28 +/- 0.55 times baseline and returned to preischemic levels by 40 min, i.e., during reperfusion. Glycine concentrations increased to 5.41 +/- 0.91 times over baseline and remained elevated for the duration of the study.(ABSTRACT TRUNCATED AT 250 WORDS)

Tuberculosis in the inner city: impact of a continuing epidemic in the 1990s

Tuberculosis cases have recently declined in the United States, renewing interest in disease elimination. We examined the epidemiology of tuberculosis from 1991 through 1997 at an inner-city public hospital and assessed population-based tuberculosis rates by ZIP code in the 8 metropolitan Atlanta counties. During the 7 years, 1378 new patients had tuberculosis diagnosed at our hospital (mean, 197 patients/year), accounting for 25% of tuberculosis cases in Georgia. Coinfection with human immunodeficiency virus (HIV) was common, but a significant decrease in the proportion of HIV-infected patients with tuberculosis was noted over time. Most patients were members of a minority group (93%) and were born in the United States (96%). Two inner-city ZIP code areas had annual tuberculosis rates >120 cases per 100,000 persons, and 8 ZIP code areas had annual rates of 47-88 cases per 100,000 persons between 1993 and 1997, compared with the annual national average of 8.7 cases per 100,000 persons. Our hospital continues to care for large numbers of tuberculosis patients, and rates of tuberculosis remain high in the inner city. These data mandate a concentration of efforts and resources in urban locations if tuberculosis control and elimination is to be achieved in the United States.

The medical database as a tool for improving maternal/infant continuity of care

Analysis of the Sinai Health System's integrated medical database revealed a serious discontinuity of care, frequently observed in underserved communities, for mothers who delivered at the hospital but failed to return on a timely basis for postpartum visits for themselves and newborn visits for their babies. Since the Sinai Health System (SHS) is a fully integrated health system including community-based primary care, a process improvement project to improve rates of return was initiated. Prior to hospital discharge, a staff member visited each new mother and baby to schedule clinic follow-up appointments. Appointment compliance was monitored using the SHS integrated medical database. Results after the first year showed marked improvement. Eighty percent of mothers returned for postpartum care within 4 months of delivery compared to 46 at baseline. Eighty eight percent of newborns were seen in the clinics within the four month timeframe compared to a baseline of 59%. The integrated medical database not only allowed for identification of this problem but was an essential tool at each point in the intervention.

Identification of differentially expressed mRNA in prokaryotic organisms by customized amplification libraries (DECAL): the effect of isoniazid on gene expression in Mycobacterium tuberculosis

Understanding the effects of the external environment on bacterial gene expression can provide valuable insights into an array of cellular mechanisms including pathogenesis, drug resistance, and, in the case of Mycobacterium tuberculosis, latency. Because of the absence of poly(A)+ mRNA in prokaryotic organisms, studies of differential gene expression currently must be performed either with large amounts of total RNA or rely on amplification techniques that can alter the proportional representation of individual mRNA sequences. We have developed an approach to study differences in bacterial mRNA expression that enables amplification by the PCR of a complex mixture of cDNA sequences in a reproducible manner that obviates the confounding effects of selected highly expressed sequences, e.g., ribosomal RNA. Differential expression using customized amplification libraries (DECAL) uses a library of amplifiable genomic sequences to convert total cellular RNA into an amplified probe for gene expression screens. DECAL can detect 4-fold differences in the mRNA levels of rare sequences and can be performed on as little as 10 ng of total RNA. DECAL was used to investigate the in vitro effect of the antibiotic isoniazid on M. tuberculosis, and three previously uncharacterized isoniazid-induced genes, iniA, iniB, and iniC, were identified. The iniB gene has homology to cell wall proteins, and iniA contains a phosphopantetheine attachment site motif suggestive of an acyl carrier protein. The iniA gene is also induced by the antibiotic ethambutol, an agent that inhibits cell wall biosynthesis by a mechanism that is distinct from isoniazid. The DECAL method offers a powerful new tool for the study of differential gene expression.

Delayed treatment with an adenosine kinase inhibitor, GP683, attenuates infarct size in rats with temporary middle cerebral artery occlusion

BACKGROUND AND PURPOSE

Brain ischemia is associated with a marked increase in extracellular adenosine levels. This results in activation of cell surface adenosine receptors and some degree of neuroprotection. Adenosine kinase is a key enzyme controlling adenosine metabolism. Inhibition of this enzyme enhances the levels of endogenous brain adenosine already elevated as a result of the ischemic episode. We studied a novel adenosine kinase inhibitor (AKI), GP683, in a rat focal ischemia model.

METHODS

Four groups of 10 adult Sprague-Dawley rats were exposed to 90 minutes of temporary middle cerebral artery (MCA) occlusion. Animals were injected intraperitoneally with vehicle, 0.5 mg/kg, 1.0 mg/kg, or 2.0 mg/kg of GP683 30, 150, and 270 minutes after the induction of ischemia by a researcher blinded to treatment group. The animals were euthanatized 24 hours after MCA occlusion, and brains were stained with 2,3,5-triphenyltetrazolium chloride. We measured brain temperatures in a separate group of 6 rats before and after administration of 1.0 mg/kg GP683.

RESULTS

All treated groups showed a reduction in infarct volumes, but a significant effect was observed only in the 1.0 mg/kg-dose group (44% reduction, P=0.0077). Body weight, physiological parameters, neurological scores, and mortality did not differ among the 4 groups. No apparent behavioral side effects were observed. Brain temperatures did not change after drug injection.

CONCLUSIONS

Our results indicate that the use of AKIs offers therapeutic potential and may represent a novel approach to the treatment of acute brain ischemia. The therapeutic effect observed was not caused by a decrease in brain temperature.

Contribution of rpoB mutations to development of rifamycin cross-resistance in Mycobacterium tuberculosis

The contributions of 23 insertion, deletion, or missense mutations within an 81-bp fragment of rpoB, the gene encoding the beta-subunit of the DNA-dependent RNA polymerase of Mycobacterium tuberculosis, to the development of resistance to rifamycins (rifampin, rifabutin, rifapentine, and KRM-1648) in 29 rifampin-resistant clinical isolates were defined. Specific mutant rpoB alleles led to the development of cross-resistance to all rifamycins tested, while a subset of mutations were associated with resistance to rifampin and rifapentine but not to KRM-1648 or rifabutin. To further study the impact of specific rpoB mutant alleles on the development of rifamycin resistance, mutations were incorporated into the rpoB gene of M. tuberculosis H37Rv, contained on a mycobacterial shuttle plasmid, by in vitro mutagenesis. Recombinant M. tuberculosis clones containing plasmids with specific mutations in either codon 531 or 526 of rpoB exhibited high-level resistance to all rifamycins tested, whereas clones containing a plasmid with a mutation in codon 516 exhibited high-level resistance to rifampin and rifapentine but were susceptible to both rifabutin and KRM-1648. These results provided additional proof of the association of specific rpoB mutations with the development of rifamycin resistance and corroborate previous reports of the usefulness of rpoB genotyping for predicting rifamycin-resistant phenotypes.

Molecular beacon sequence analysis for detecting drug resistance in Mycobacterium tuberculosis

We developed a new approach to DNA sequence analysis that uses fluorogenic reporter molecules--molecular beacons--and demonstrated their ability to discriminate alleles in real-time PCR assays of genomic DNA. A set of overlapping molecular beacons was used to analyze an 81-bp region of the Mycobacterium tuberculosis rpoB gene for mutations that confer resistance to the antibiotic rifampin. In a blinded study of 52 rifampin-resistant and 23 rifampin-susceptible clinical isolates, this method correctly detected mutations in all of the resistant strains and in none of the susceptible strains. The assay was carried out entirely in sealed PCR tubes and was simple to perform and interpret. This approach can be used to analyze any DNA sequence of moderate length with single base pair accuracy.

Pre- and peristroke treatment with the adenosine kinase inhibitor, 5'-deoxyiodotubercidin, significantly reduces infarct volume after temporary occlusion of the middle cerebral artery in rats

The adenosine kinase inhibitor, 5'-deoxyiodotubercidin (5dITU), was examined in a rat focal stoke model with temporary (105 min) middle cerebral artery occlusion (MCAO) followed by a 24 h recovery period. Inhibition of this adenosine metabolizing enzyme indirectly enhances the actions of endogenous adenosine without inducing cardiovascular side effects. Such effects could limit the potential clinical application of any approach targeting adenosine receptor activation. MCAO was accomplished with a transluminal 4-0 nylon suture inserted through the common carotid artery to block blood flow at the origin of the MCA. Treatment with 5dITU 30 min prior to and 5 h after MCAO resulted in a dose dependent (0.1-0.5 mg/kg, i.p.) reduction in infarct volume. A significant (P = 0.02) 44% reduction (control, 265 +/- 35 mm3; treated, 149 +/- 30 mm3) was observed at 0.5 mg/kg. However, at the highest dose examined (1.0 mg/kg) infarct volume was unaffected. To assess the potential for acute (i.e. post-occlusion) treatment, 5dITU was administered (0.33 mg/kg, i.v.) successively at each of 0.5, 1.75 and 3.5 h after MCAO. Post-occlusion treatment resulted in a significant (P = 0.037) 32% reduction in infarct volume (control, 314 +/- 34 mm3; treated, 212 +/- 28 mm3). At this dose there were no apparent changes in a number of physiological parameters monitored over the period of MCAO. The present study shows that intervention with an adenosine kinase inhibitor in an ischemic brain injury model is neuroprotective whether treatment is begun prior to or just after MCAO.

Morphologic, immunologic, and cytogenetic classification of acute myeloid leukemia and myelodysplastic syndrome in childhood: a report from the Childrens Cancer Group

The purposes of this report are to reaffirm concordance difficulties with the acute myeloid leukemia (AML) French-American-British (FAB) classification, to present the frequency of previously delineated AML syndromes in pediatric patients and to describe additional characteristic AML profiles utilizing composite morphologic, cytogenetic and immunophenotypic data. Profiles of 124 children with acute myeloid leukemia (AML) and 13 children with myelodysplastic syndrome entered on the Childrens Cancer Group (CCG) pilot study CCG-2861 were examined. Concordance between institutions and reviewers for FAB designation was 65%. Discordance was found principally between M1 and M2, M2 and M4, and M4 and M5. In 49% of marrow specimens, leukemic blasts expressed at least one T lineage-related antigen; 24% expressed the B lineage-related antigen CD19. CDw14 correlated with FAB M4 or M5 morphology and was the only surface antigen associated with a specific FAB subtype. Normal karyotypes were found for 15% of the 75 children with satisfactory karyotype preparations. Recurring aberrations, found in 76% of children, included t(15;17)(q22;q11), t(8;21)(q22;q22), inv(16)(p13q22), rearrangements of band 11q23, t(6;9) (p23;q34), trisomy 8 and monosomy 7. Results from this pilot study and from the current CCG randomized trial correlating morphology, immunophenotyping and cytogenetics, will help to classify AML into unique subgroups with differing clinical consequences or therapy requirements.

Thyrotropin and prolactin responses to thyrotropin-releasing hormone in young men at high or low risk for alcoholism

A reduced thyrotropin (TSH) response to TSH-releasing hormone (TRH) has been reported in a portion of abstinent alcoholic men without evidence of cirrhosis of the liver. It is not known whether this neuroendocrine change is a precursor of alcoholism or a sequelae of heavy alcohol consumption. Three of four published studies have found evidence for differences in TRH-induced TSH response in subjects at high risk for alcoholism, based on family history, compared with subjects at low risk for alcoholism. To test further the hypothesis that the TRH-induced TSH response is a vulnerability marker for alcoholism, we tested 25 young men with an alcoholic father [family history-positive (FHP)] and matched them, on alcohol consumption, to 25 young men with no identified first- or second-degree relatives with alcoholism [family history-negative (FHN)]. FHP subjects were further categorized based on whether their father had shown signs of alcohol problems before age 25 years (FHP-Early, n = 10) or after age 24 years (FHP-Late, n = 12). FHP subjects did not differ from FHN subjects in their baseline levels of thyroid hormones, glucose, cortisol, or TSH. However, the distribution of TSH responses in the FHP subjects was skewed toward lower values, compared with FHN subjects (p = 0.12). Furthermore, FHP-Late subjects had lower TSH responses than FHN subjects (p = 0.02), whereas the TSH response of FHP-Early subjects was not different from FHN subjects. Prolactin responses to TRH were similar across all groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Acadesine reduces indium-labeled platelet deposition after photothrombosis of the common carotid artery in rats

BACKGROUND AND PURPOSE

The adenosine-regulating agent acadesine has been shown to reduce the incidence of myocardial infarction and stroke after cardiopulmonary bypass surgery. The present study examined the effect of acadesine on the accumulation of indium-labeled platelet emboli and infarct size after photothrombosis of the common carotid artery.

METHODS

Rats were anesthetized with halothane and preloaded with 111In-tropolone-labeled platelets (50 to 80 microCi) 30 minutes before nonocclusive common carotid artery thrombosis induced by a rose bengal-mediated photochemical insult. Intravenous infusion of acadesine (0.5, 1, or 2 mg/kg per minute) or vehicle was begun 30 minutes before right common carotid artery thrombosis and continued for an additional 15 minutes. Rats were then killed and brains processed for the autoradiographic quantitation of labeled platelet aggregates. In a separate group of rats, infarct areas and volumes were determined in treated (acadesine 1 mg/kg per minute) (n = 9) and nontreated (n = 9) rats 7 days after thrombosis.

RESULTS

Although the ratio of right-to-left common carotid artery radioactivity was not affected by treatment, acadesine at 1 and 2 mg/kg per minute significantly decreased (P < .01) platelet deposition within the right cerebral cortex, hippocampus, and striatum. For example, within the frontoparietal cortex, numbers of platelet aggregates were 11.8 +/- 1.8 (mean +/- SEM), 6.1 +/- 1.4, 2.3 +/- 0.6, and 3.2 +/- 0.8 in rats infused with vehicle, 0.5, 1, and 2 mg/kg per minute acadesine, respectively. In addition, infarct volume was reduced by 48% in acadesine-treated (1 mg/kg per minute) rats, with a significant reduction in infarct area at the coronal level 3.7 mm anterior to bregma (P < .01).

CONCLUSIONS

These results support a prophylactic role for acadesine in reducing the accumulation of platelet emboli during vascular thrombosis and subsequent brain infarction. Acadesine treatment in patients at risk for embolic stroke could potentially lead to cerebral protection.

The rpoB gene of Mycobacterium tuberculosis

A portion of the Mycobacterium tuberculosis gene encoding the beta subunit of RNA polymerase (rpoB) was amplified by PCR using degenerate oligonucleotides and used as a hybridization probe to isolate plasmid clones carrying the entire rpoB gene of M. tuberculosis H37Rv, a virulent, rifampin-susceptible strain. Sequence analysis of a 5,084-bp SacI genomic DNA fragment revealed a 3,534-bp open reading frame encoding an 1,178-amino-acid protein with 57% identity with the Escherichia coli beta subunit. This SacI fragment also carried a portion of the rpoC gene located 43 bp downstream from the 3' end of the rpoB open reading frame; this organization is similar to that of the rpoBC operon of E. coli. The M. tuberculosis rpoB gene was cloned into the shuttle plasmid pMV261 and electroporated into the LR223 strain of Mycobacterium smegmatis, which is highly resistant to rifampin (MIC > 200 micrograms/ml). The resulting transformants were relatively rifampin susceptible (MIC = 50 micrograms/ml). Using PCR mutagenesis techniques, we introduced a specific rpoB point mutation (associated with clinical strains of rifampin-resistant M. tuberculosis) into the cloned M. tuberculosis rpoB gene and expressed this altered gene in the LR222 strain of M. smegmatis, which is susceptible to rifampin (MIC = 25 micrograms/ml). The resulting transformants were rifampin resistant (MIC = 200 micrograms/ml). The mutagenesis and expression strategy of the cloned M. tuberculosis rpoB gene that we have employed in this study will allow us to determine the rpoB mutations that are responsible for rifampin resistance in M. tuberculosis.

Blood-brain barrier transport and brain metabolism of adenosine and adenosine analogs

Adenosine transport through the brain capillary endothelial wall, which makes up the blood-brain barrier (BBB) in vivo, is mediated by a saturable transport system that has not been characterized extensively. Moreover, the inability of adenosine to augment cerebral blood flow in most species after intracarotid adenosine administration suggests the presence of an enzymatic BBB to circulating adenosine. Therefore, the present studies investigate the Michaelis-Menten kinetics of BBB adenosine transport and the rate of cerebral metabolism of circulating adenosine after internal carotid artery perfusion in anesthetized rats. The studies also assess the ability of various adenosine analogues to inhibit [3H]adenosine transport at the BBB in vivo. Initial rates of BBB transport of adenosine in vivo were observed for at least 15 sec of internal carotid artery perfusion. BBB adenosine transport was partially sodium-dependent and was saturable with the following kinetic parameters: Km = 1.1 +/- 0.2 microM; Vmax = 202 +/- 44 pmol/min/g; and KD = 34 +/- 6 microliters/min/g. BBB transport of [3H]adenosine was not inhibited by cyclohexyladenosine or S-(4-nitrobenzyl)-6-thioinosine, but was inhibited by dipyridamole (Ki = 2.2 +/- 0.9 microM). Capillary depletion studies were performed, which demonstrated sequestration of [3H] radioactivity by the microvascular pellet after carotid arterial infusion of [3H]adenosine. Only 10 +/- 3% of cerebral [3H] radioactivity resided in the free adenosine pool after 15 sec of internal carotid artery perfusion of [3H]adenosine and rapid termination of brain metabolism with microwave irradiation.(ABSTRACT TRUNCATED AT 250 WORDS)

Forebrain ischemia in the gerbil increases lambda opiate binding in hippocampal mossy fibers

Transient forebrain ischemia was produced in gerbils by short-term occlusion of the common carotid arteries under halothane anesthesia. Histological analysis of brains 7 days post-ischemia demonstrated characteristic destruction of CA1 pyramidal cells. lambda Opiate binding (measured with [3H]naloxone in the presence of 300 nM diprenorphine) at 7 days post-ischemia was significantly increased in the stratum lucidum of the hippocampus (the mossy fiber layer), but not in any other region measured, including other hippocampal regions, cortex, amygdala, caudate putamen, thalamus, and hypothalamus. The increase in mossy fiber lambda binding was slow to develop (no increase detected up to 48 h post-ischemia), and long-lasting (binding remained elevated at 32 days post-ischemia). While MK-801 significantly inhibited CA1 pyramidal cell destruction when administered 20 min prior to ischemia, the increase in mossy fiber lambda binding was still evident. None of seven different opioid agonists and antagonists examined had an effect on either the pyramidal cell damage or increased mossy fiber lambda binding seen 7 days after ischemia.

Therapeutic potential for adenosine receptor activation in ischemic brain injury

The present report reviews the biochemical and physiological responses to adenosine receptor activation and how these responses underlie the ability of adenosine to couple energy demand with energy supply. In addition, activation of adenosine receptors pharmacologically is shown to initiate various reactions which could be responsible for the observed adenosine-mediated attenuation of the neuropathological consequences of brain ischemia. Also reported is the extent to which side effects such as hypothermia can contribute to the observed efficacy of adenosine agonist administration in the small animal model of ischemia. Data from various in vitro and in vivo ischemia studies is presented showing that neuroprotection can be achieved following pharmacological activation of adenosine receptors either through agonists with high affinity for A1 adenosine receptors or drugs which potentiate endogenous adenosine levels. In general the data support utilization of adenosine receptor activation as a means of attenuating ischemic brain damage.

Effects of traumatic brain injury in rats on binding to forebrain opiate receptor subtypes

Sprague-Dawley rats were subjected to a moderate level (2.2 atm) of traumatic brain injury (TBI) using fluid percussion. Injured animals were allowed to survive posttrauma for periods of 5 min, 3 h, and 24 h. The effect of TBI on binding to forebrain opiate receptors was assessed using quantitative receptor autoradiography, and compared to a sham control group. Binding of [3H]DAGO to mu receptors in neocortex and the CA1 pyramidal layer of the hippocampus was significantly decreased in the 24-h group (p less than 0.05). [3H]Bremazocine binding to kappa receptors was unchanged at 5 min and 24 h, but showed large decreases 3 h after TBI in the CA1 pyramidal layer (65%, p less than 0.05) and dentate gyrus (43%, p less than 0.05). Levels of delta binding (measured with [3H]DSLET) and lambda binding (measured with [3H]naloxone) were unaffected by TBI. These data support previous suggestions of a role for endogenous opioids in TBI, and provide further evidence that mu and kappa opioid receptor subtypes in neocortex and hippocampus may have different functions in TBI.

Successful reinduction therapy with amsacrine and cyclocytidine in acute nonlymphoblastic leukemia in children. A report from the Childrens Cancer Study Group

Amsacrine (AMSA) and cyclocytidine were studied as retrieval therapy in 122 pediatric patients with acute nonlymphoblastic leukemia (ANLL). Patients either failed to achieve sustained initial remissions or were in relapse. Induction therapy consisted of intravenous (IV) AMSA (75 mg/m2) from days 1 to 5 and subcutaneous cyclocytidine (600 mg/m2) from days 1 to 7. Maintenance therapy consisted of IV etoposide (VP-16) (100 mg/m2) for 5 days and IV AMSA (100 mg/m2) on day 1. Of 122 patients, 109 were evaluable. There were 13 early deaths. Ninety-six patients received adequate therapy defined as completion of two courses of therapy. Of these 96 patients, 52 achieved complete remission. Fifteen of 33 patients who failed initial induction achieved complete remission. Eighteen of 39 patients who were resistant to anthracyclines had complete responses. There was no direct evidence of AMSA-induced cardiotoxicity. Remission duration was 28 days to 3 or more years (median, 98 days). AMSA and cyclocytidine were effective retrieval therapy for patients who were in relapse or unresponsive to frontline therapy. Duration of remission was short (median, 98 days).