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).

Excitatory amino acid receptor subtype binding following traumatic brain injury

Sprague-Dawley rats were subjected to a moderate level (2.2 atm) of traumatic brain injury (TBI) using fluid percussion. Injured animals were allowed post-trauma survival periods of 5 min, 3 and 24 h. Regional glutamate receptor subtype binding was assessed with quantitative autoradiography in each group for N-methyl-D-aspartate (NMDA), quisqualate and kainate receptor subpopulations at approximately the -3.8 bregma level and compared to a sham control group. [3H]glutamate binding to the NMDA receptor was significantly (P less than 0.05) decreased at 3 h post-TBI in the hippocampal CA1 stratum radiatum, the molecular layers of the dentate gyri and the outer (layers 1-3) and inner (layers 5 and 6) overlying neocortex. NMDA receptor binding was significantly reduced in layers 5 and 6 of the neocortex at all post-trauma survival times but no further differences were seen in the hippocampi. No significant changes were observed with [3H]AMPA binding to quisqualate receptors and [3H]KA binding was significantly reduced only in layers 5 and 6 of the neocortex at 24 h after TBI. These data further confirm the pathological involvement of the NMDA receptor complex in brain regions selectively vulnerable to moderate levels of TBI in this model.

The ontogeny of excitatory amino acid receptors in the rat forebrain--II. Kainic acid receptors

The ontogeny of [3H]kainic acid binding in rat forebrain was studied quantitatively using in vitro receptor autoradiography. Specific binding was detectable in ventral thalamus, hippocampus, striatum and olfactory bulb by postnatal day 1. In regions with high densities of receptors in adulthood, such as CA3, dentate gyrus and striatum, binding increased progressively across development peaking at postnatal day 21. In ventral thalamus and the inner lamina of the neocortex, [3H]kainic acid binding was high in the first three postnatal weeks and relatively low thereafter. Saturation studies performed on adults and 14-day-old animals suggest differences in both the affinity and the maximal binding capacity contributed to the observed developmental changes in binding of [3H]kainic acid.

The ontogeny of excitatory amino acid receptors in rat forebrain--I. N-methyl-D-aspartate and quisqualate receptors

The ontogeny of radioligand binding to N-methyl-D-aspartate and quisqualate receptors in rat forebrain was studied quantitatively using in vitro receptor autoradiography. Specific binding to both receptors could be detected by postnatal day 1 in hippocampus and striatum. The adult pattern of binding to N-methyl-D-aspartate receptors emerged by postnatal day 14 with high densities of binding in CA1 (stratum oriens and stratum radiatum), dentate gyrus (molecular layer) and striatum (caudate-putamen). Binding to the outer laminae of frontal cortex was as much as 45% above adult levels during development. Binding of [3H]amino-3-hydroxy-5-methylisoxazole-4-propionic acid to quisqualate receptors showed a similar overshoot during development, but also manifested a unique distribution with CA3 and medial aspects of the amygdala exhibiting transient, intense labeling. Homogenate binding studies with [3H]amino-3-hydroxy-5-methylisoxazole-4-propionic acid demonstrated a 73% increase in quisqualate receptors in whole brain at postnatal day 21 compared with adult levels. The selectivity of excitatory amino acid binding to the quisqualate site in development was similar to the selectivity in adult brain. These data taken with other recent reports, suggest that quisqualate receptors may have a role in development distinct from their function in the adult brain.

Opiate receptor subtype binding in gerbil hippocampus is altered by forebrain ischemia

A role for endogenous opioids in trauma-induced brain injury has been supported by pharmacological studies. The present series of experiments were initiated to extend these observations by measuring opiate receptor subtype binding in gerbil hippocampus following 7 days recovery from a 10 min ischemic insult. Quantitative in vitro autoradiography was utilized to measure mu [( 3H]DAGO), kappa [( 3H]bremazocine + 10 microM morphiceptin + 100 nM DSLET), delta [( 3H]DSLET + 10 microM morphiceptin) and lambda [( 3H]naloxone + 300 nM diprenorphine) binding. While ischemic tissue samples at the level of the dorsal hippocampus showed complete loss of CA1 pyramidal cells, we observed no significant alterations in mu or delta binding suggesting a non-pyramidal cell localization of these receptors. Kappa binding decreased significantly to 88% of control in the CA1 and CA3 regions while lambda binding in the stratum lucidum (CA3) increased to 165% of control. Our results show that opiate receptor subtypes are differentially affected by an ischemic insult.

Rat pup isolation distress and the brain benzodiazepine receptor

Pharmacologic studies have demonstrated that benzodiazepines can modulate the ultrasonic vocalizations (USV) associated with social separation of rat pups. In this study, in vivo receptor autoradiography was used to determine if brain benzodiazepine receptors were functionally less available to bind an exogenous ligand during social separation. The labeled benzodiazepine receptor antagonist. 3H-RO 15-1788, was given to 10-day-old rat pups with varying schedules of social separation. In initial studies with homogenized and solubilized tissue, we found a 30% reduction in binding to cortex when pups were separated for 25 min beginning 5 min prior to tracer injection. In subsequent autoradiographic studies with this same separation schedule, the binding of 3H-RO 15-1788 was examined in 21 brain regions. Again binding was decreased in neocortex (frontal, motor, and somatosensory). In addition, we found significantly decreased binding in hippocampus, dentate gyrus, and superior and inferior colliculi. These same regions showed no alteration of in vitro binding of 3H-RO 15-1788. Therefore, these decreases in in vivo binding do not reflect changes in receptor number. The interpretation of decreased in vivo binding and implications of these results for defining the neural substrates of separation behavior are discussed.

Combined pretrauma scopolamine and phencyclidine attenuate posttraumatic increased sensitivity to delayed secondary ischemia

Fasted Wistar rats were given a mild level of traumatic brain injury (TBI) and then subjected to 6 min of transient forebrain ischemia 24 h posttrauma. One group was given simultaneous 1 mg/kg scopolamine and 4 mg/kg phencyclidine intraperitoneally (IP) 15 min before trauma and another group an equal volume of plasmalyte A solution. After 7 days of postinjury survival, placebo-treated rats demonstrated increased posttraumatic vulnerability to secondary ischemic CA1 neuronal death even 24 h after trauma. This finding confirmed that increased posttraumatic ischemic vulnerability persists for at least 24 h even following mild trauma. Combined muscarinic receptor and N-methyl-D-aspartate (NMDA) receptor coupled ion channel blockade given and present during the mild TBI statistically attenuated this enhanced secondary ischemic CA1 neuronal death and thus posttraumatic increased ischemic vulnerability. Placebo-treated rats had 335.3 +/- 93.6 CA1 neurons/10(6) microns 2 and drug-treated rats had 844.8 +/- 184.9 CA1 neurons/10(6) microns 2. This result suggests that muscarinic and/or NMDA receptor-mediated events confined to TBI and the early posttraumatic period are in part responsible for the phenomenon of increased posttraumatic ischemic vulnerability.

Epidemiologic programs for computers and calculators. Exact binomial confidence intervals for the relative risk in follow-up studies with sparsely stratified incidence density data

The authors present a computer program for hypothesis testing and calculation of exact binomial confidence intervals for the adjusted relative risk in follow-up studies involving multiple strata with incidence density (person-time) denominators and small or zero person-count numerators. The program is an extension to multiple tables of a single-table method by Rothman and Boice (NIH publication no. 79-1649, Washington, DC: US GPO, 1979) and represents a counterpart for person-time denominators to the program of Thomas (Comput Biomed Res 1975;8:423-46) for exact analysis of multiple tables with person-count denominators. Comparisons with asymptotic analyses of real and simulated data are given. Copies of the program are available from the authors on request.

Effect of pharmacological doses of 3-0-methyl-D-glucose and 2-deoxy-D-glucose on rat brain glucose and lactate

The present investigation examined the effects of two glucose analogues, 3-0-methyl-D-glucose (30MG) and 2-deoxy-D-glucose (2DOG) on basal levels of rat brain glucose and lactate. The results showed that pretreatment (iv) with 30MG up to 2 g/kg caused a transient drop in brain glucose levels to 42% of control value within 2.5 min and a drop in lactate levels to 75% of control value by 5 min. 2DOG administration (2 g/kg) affected glucose in a biphasic response with an initial drop to 46% of control value seen by 2.5 min, followed by a progressive increase to 290% of the control value by 40 min. This elevated level of glucose was sustained for approximately 40 min. Lactate levels responded to 2DOG administration by a decrease to 37% of control value within 10 min post-injection and returned to near basal levels by 160 min. A dose response was also examined for both compounds. Behaviorally 30MG had no apparent effects. However, the response to 2DOG was a reduction in voluntary movements, piloerection, irregular clonic jerks, splayed limbs and fits of wild running. These experiments were designed to evaluate the potential of 30MG or 2DOG for attenuating the well documented rise in brain lactate levels following an ischemic insult. Our results suggest that under certain experimental conditions either 30MG or 2DOG could prevent brain lactate rise and might have beneficial effects in minimizing the neuropathological consequences of ischemic damage that could be related to increases in brain lactate.

Tetrahydrobiopterin in dystonia: identification of abnormal metabolism and therapeutic trials

The pteridine cofactor of tyrosine and tryptophan hydroxylases, tetrahydrobiopterin (BH4), is concentrated in the striatum and other sites of brain monoamine synthesis and is a regulatory factor in the rate-limiting step of catecholamine synthesis. CSF content was decreased in eight patients with dystonic disorders (mean, 13.0 +/- 0.8 pmol/ml CSF compared with 20.6 +/- 1.4 in age-matched normals). We gave several trials of synthetic BH4 intravenously to 10 dystonic patients with benefit for 2 subjects with diurnally fluctuating dystonia, 1 with hemidystonia and parkinsonism, and 1 with generalized torsion dystonia. The findings of biopterin abnormality and the observed clinical improvements may point to a role for the cofactor in the pathogenesis and, possibly, the treatment of some forms of primary dystonia.

Regional kinetic constants for blood-brain barrier pyruvic acid transport in conscious rats by the monocarboxylic acid carrier

The present investigation using labeled pyruvate describes the regional distribution and kinetics of the monocarboxylic acid carrier at the blood-brain barrier of conscious rats. The experimental procedure involved the arterial injection of a single bolus of 200 microliter containing [1-14C]pyruvate, [3H]water, and varying concentrations of unlabeled pyruvate into the common carotid via an indwelling externalized catheter. The hemisphere ipsi-lateral to the injection and rostral to the midbrain was removed and dissected into five regions. A kinetic analysis revealed no significant regional differences in Km values with an overall average of 1.37 mM. However, there was regional variation in the density of the monocarboxylic acid carrier as indicated by varied levels of the kinetic constant Vmax. The cortex showed the highest Vmax value of 0.42 +/- 0.08 mumol/min/g whereas values for the caudate/putamen, thalamus/hypothalamus, and remaining portion of hemisphere ranged significantly lower at 0.22-0.27 mumol/min/g. The Vmax for the hippocampus was intermediate at 0.37 +/- 0.12 mumol/min/g. The nonsaturable carrier described kinetically by KD had an overall average of 0.034 ml/min/g. The present study confirms quantitatively previous results suggesting a variable regional distribution of the monocarboxylic acid carrier.

Pretreatment with 3-O-methyl-D-glucose or 2-deoxy-D-glucose attenuates the post-mortem rise in rat brain lactate

The present investigation examined the effects of pretreatment with 3-O-methyl-D-glucose (3OMG) or 2-deoxy-D-glucose (2DOG) on post-mortem rise in rat brain lactate to evaluate their potential use for minimizing ischemia-induced rise in brain lactate. The results showed that iv administration of either glucose analogue (2 g/kg) at 2.5 min prior to sacrifice significantly attenuated (to 0.61 of control levels) post-mortem brain lactate rise. Pretreating rats with 2-deoxy-D-glucose (2 g/kg) 15 min prior to sacrifice resulted in a greater inhibition (to 0.52 of control) of the post-mortem lactate rise. The effects of these two analogues (3OMG and 2DOG) can be accounted for by their inhibition of brain glucose transport and inhibition of brain glucose metabolism by 2DOG. The present results suggest that intervention with either of these glucose analogues under the proper experimental procedures may minimize the cytopathological consequences of ischemia related to the rise in brain lactate.

Carotid artery injection technique: bounds for bolus mixing by plasma and by brain

Estimation of Michaelis-Menten kinetic parameters (Km, Vmax) of blood-brain barrier (BBB) transport processes with the carotid artery single injection technique assumes that mixing of the bolus with unlabeled substrate either from (a) circulating plasma or (b) amino acid efflux from brain, is minimal. The maximum extent to which the bolus could mix by these two sources is quantified in the present studies by measuring 14C-phenylalanine extraction in pentobarbital-anesthetized and conscious rats after the addition of 0-80% rat serum to the arterial injection solution. An upper bound (+/- SE) of bolus mixing due to mixing from both sources, expressed in terms of percentage of rat plasma, is 8.8 +/- 1.9 and 7.0 +/- 2.1% for the anesthetized and conscious rat, respectively. The estimated contribution to bolus mixing due to amino acid efflux from brain is 3.3 and 2.1% for the anesthetized and conscious rat, respectively. Based on these estimates, the upper bound for bolus mixing with circulating rat plasma is only 5.5 and 4.9%, respectively, for the anesthetized and conscious catheterized rat. Thus, any bolus mixing after rapid carotid injection is relatively small and is comparable to the mixing effects observed with the carotid artery infusion technique. Mixing effects on the order of 5% are shown to have no significant effect on the estimation of kinetic parameters of BBB nutrient transport, except for neutral and basic amino acid transport, which are characterized by very low Km values relative to the usual amino acid plasma concentrations.(ABSTRACT TRUNCATED AT 250 WORDS)

Kinetic constants for blood-brain barrier amino acid transport in conscious rats

The kinetic constants for large neutral amino acid (LNAA) transport across the blood-brain barrier (BBB) of conscious rats were determined in four brain regions: cortex, caudate-putamen, hippocampus, and thalamus-hypothalamus. Indwelling external carotid artery catheters allowed for single-bolus (200 microliters) injections directly into the arterial system of unanesthetized and lightly restrained animals. Our results showed lower brain uptake index values for conscious rats compared to previous reports for anesthetized animals which are consistent with higher rates of cerebral blood flow in the conscious animals. Km values were lower in the conscious animals and ranged from 29% to 87% of the Km values in pentobarbital-anesthetized animals whereas the KD values were about twofold higher in the conscious animals. No apparent regional differences were observed. Influx rates were determined which take into consideration flow rates and plasma amino acid concentrations. Our results showed an average amino acid influx value of 5.2 nmol/min/g, which is 53% higher than the average influx in pentobarbital-anesthetized animals. The present results in conscious animals regarding the low Km of LNAA transport across the BBB lend further support to the importance of fluctuations in plasma amino acid concentrations and LNAA transport competitive effects on brain amino acid availability.

Kinetics of regional blood-brain barrier glucose transport and cerebral blood flow determined with the carotid injection technique in conscious rats

Anesthetics, particularly barbiturates, have depressive effects on cerebral blood flow and metabolism and likely have similar effects on blood-brain barrier (BBB) transport. In previous studies utilizing the carotid injection technique, it was necessary to anesthetize the animals prior to performing the experiment. The carotid injection technique was modified by catheter implantation in the external carotid artery at the bifurcation of the common carotid artery. The technique was used to determine cerebral blood flow, the Km, Vmax, and KD of glucose transport in hippocampus, caudate, cortex, and thalamus-hypothalamus in conscious rats. Blood flow increased two to three times from that seen in the anesthetized rat. The Km in the four regions ranged between 6.5 and 9.2 mM, the Vmax ranged between 1.15 and 2.07 mumol/min/g, and the KD ranged between 0.015 and 0.035 ml/min/g. The Km and KD in the conscious rat did not differ from the values seen in the barbiturate anesthetized rat. The Vmax, on the other hand, increased two- to three-fold from that seen in the anesthetized rat and was nearly proportional to the increase in blood flow seen in the conscious rat. The development of the external carotid catheter technique now allows for determination of BBB substrate transport in conscious animals.

Sequential combination of methotrexate and vindesine in previously treated children with acute leukemia. A phase I-II study

A therapeutic synergistic effect is seen in animal models when vinca alkaloids are administered after methotrexate. To examine further this interaction in clinical studies, a phase I-II trial was conducted in children with hematologic malignancies in the Department of Pediatrics at Memorial Sloan-Kettering Cancer Center. A schedule of sequential of methotrexate and vindesine was developed which showed effect in acute lymphoblastic leukemia in children in relapse and which was relatively nontoxic. The regimen has also been useful for reinduction for patients who are candidates for bone marrow transplant.

Effects of methotrexate on biopterin levels and synthesis in rat cultured pineal glands

Culture of rat pineal glands in methotrexate (0.5, 5, or 10 microM) for 6 or 24 h did not alter pineal tetrahydrobiopterin (85-90% of total biopterin in cultured glands), except for a decrease of 30% after 24 h culture in 10 microM methotrexate. However, pineal dihydrobiopterin and/or biopterin (10-15% of total biopterin) was increased by methotrexate up to 2.5-fold. Biopterin detected in the culture medium following pineal culture was also increased to a similar extent after methotrexate treatment and appeared to represent leakage of pineal dihydrobiopterin and/or biopterin. Culture of glands in 5 microM methotrexate did not alter the conversion of [U-14C]-guanosine to [14C]biopterin, suggesting that pineal tetrahydrobiopterin synthesis was not altered by methotrexate. Complete inhibition of dihydrofolate reductase activity measured in pineal homogenates was obtained following culture of glands in all concentrations of methotrexate studied. Therefore, dihydrofolate reductase and dihydrobiopterin do not appear to be involved in a major biosynthetic pathway for pineal tetrahydrobiopterin from GTP, although they may have a minor role in tetrahydrobiopterin synthesis.

Studies on the disposition of quinolinic acid after intracerebral or systemic administration in the rat

Quinolinic acid (QUIN) is an endogenous, excitotoxic amino acid which is currently under investigation as a possible etiological factor in human neurodegenerative disorders such as Huntington's disease and epilepsy. We explored certain aspects of this hypothesis, using the adult rat as an experimental animal. After intrastriatal infusions of [3H]QUIN, radioactivity was cleared from the injected region with an apparent half-life of 22 min. To 2 h after injection, all radioactivity recovered from the striatum corresponded to unmetabolized QUIN. Consistent with these data was the lack of significant uptake of [3H]QUIN by slices or crude synaptosomes prepared from rat hippocampus or striatum. When applied intravenously, a high dose of QUIN (450 mg/kg) caused relatively minor seizure-related EEG changes and no signs of neuronal degeneration. Direct measurements indicated negligible penetration of the blood-brain barrier by QUIN. The lack of an effective inactivation mechanism for extracellular QUIN in the brain negates QUIN's proposed role as a classical neurotransmitter substance, but may be of significance for the postulated effects of this compound in neurodegenerative diseases. An important role of blood-borne QUIN or QUIN precursors in human disorders cannot be ruled out at present; although the brain appears to be well protected by the blood-brain barrier from an acute elevation of blood QUIN, a possible breakdown of the barrier under pathologic conditions and the effects of chronic elevations of blood QUIN remain to be examined.