Biodegradation of polycyclic aromatic hydrocarbons by Sphingomonas strains isolated from the terrestrial subsurface

Several strains of Sphingomonas isolated from deep Atlantic coastal plain aquifers at the US Department of Energy Savannah River Site (SRS) near Aiken, SC were shown to degrade a variety of aromatic hydrocarbons in a liquid culture medium. Sphingomonas aromaticivorans strain B0695 was the most versatile of the five strains examined. This strain was able to degrade acenaphthene, anthracene, phenanthrene, 2,3-benzofluorene, 2-methylnaphthalene, 2,3-dimethylnaphthalene, and fluoranthene in the presence of 400 mg l(-1) Tween 80. Studies involving microcosms composed of aquifer sediments showed that S. aromaticivorans B0695 could degrade phenanthrene effectively in sterile sediment and could enhance the rate at which this compound was degraded in nonsterile sediment. These findings indicate that it may be feasible to carry out (or, at least, to enhance) in situ bioremediation of phenanthrene-contaminated soils and subsurface environments with S. aromaticivorans B0695. In contrast, strain B0695 was unable to degrade fluoranthene in microcosms containing aquifer sediments, even though it readily degraded this polynuclear aromatic hydrocarbon (PAH) in a defined liquid growth medium.

[Evaluation of intraperitoneal chemotherapy in stage IV gastrointestinal cancer]

OBJECTIVE

To evaluate the short term and long term therapeutic effects of intraperitoneal versus intravenous chemotherapy in 56 cases with stage IV gastrointestinal cancer.

METHODS

The patients were randomly divided into two groups: 35 cases in the intraperitoneally treated group and 21 cases in the intravenously treated group. The short term effects and side effects were observed. The survival time of the patients was also recorded. The survival function was estimated by Kaplan-Meier method, and the significance test was done by Log rank method.

RESULTS

There was no significant difference between the two groups in short term effects, and liver and kidney damages. Nausea, vomiting and bone marrow suppression were more severe in the intravenously treated group, while abdominal distension and pain were the major side effects in the intraperitoneally treated group. The median survival time and one year survival rate of patients in the intraperitoneally treated group were higher than those in the intravenously treated group.

CONCLUSION

For patients with stage IV gastrointestinal cancer, intraperitoneal administration of chemotherapeutic agents is a better treatment of choice.

Conditioning the unconditioned response: modification of the rabbit's (Oryctolagus cuniculus) unconditioned nictitating membrane response

Conditioning-specific reflex modification (CRM) occurs when classical conditioning modifies responding to an unconditioned stimulus (US) in the absence of a conditioned stimulus (CS). Three experiments monitored rabbit nictitating (Oryctolagus cuniculus) membrane unconditioned responses to 5 intensities and 4 durations of periorbital electrical stimulation before and after CS or US manipulation. CRM occurred after 12 days of CS-US pairings but not following unpaired CS/US presentations or restraint. CRM survived CS-alone and CS/US-unpaired extinction of the conditioned response (CR) but not presentations of the US alone, although CRs remained intact. Thus, CRs could be weakened without eliminating CRM and CRM could be weakened without eliminating CRs. Data indicate CRM is a reliable, associative effect that is more than a generalized CR and may not be explained by habituation, stimulus generalization, contextual conditioning, or bidirectional conditioning.

Segregation of nociceptive and non-nociceptive networks in the squirrel monkey somatosensory thalamus

The somatosensory thalamus (here we examine neurons in the caudal cutaneous portion of ventral posterior lateral nucleus, VPL) is composed of a somatotopic arrangement of anteroposteriorly oriented rods. Each rod is a collection of neurons with homogeneous properties that relay sensory information to specific cortical columns. We developed a multi-electrode recording technique, using fixed-geometry four-tip electrodes that allow simultaneous recordings from small populations of neurons (4-11), in a approximately 150 x 150 x 150 micrometer(3) volume of brain tissue (i.e., the approximate diameter of rods) and study of their spatiotemporal interactions. Due to the fixed geometry of the four-tip electrodes, the relative locations of these neurons can be determined, and due to the simultaneity of the recordings, their spike-timing coordination can be calculated. With this method, we demonstrate the existence of two distinct functional networks: nociceptive and non-nociceptive networks. The population dynamics of these two types of networks are different: cross-correlations in each type of network were different in direction and strength, were a function of the distance between neurons, had an opponent organization for nociceptive networks and a non-opponent organization for non-nociceptive networks, and rapidly changed under different stimulus conditions independent of changes in firing rates. A simple neural network model mimicked these physiological findings, demonstrating the necessity of inhibitory interneurons and different amounts of afferent input synchronization. Based on these results, we conclude that the somatosensory thalamus is composed of two modules, nociceptive and non-nociceptive rods, and that the response dynamics differences between these modules are due to spatiotemporal differences of their afferent inputs.

[The mechanism of docetaxel-induced apoptosis in human lung cancer cells]

OBJECTIVE

To study the mechanism of docetaxel-induced apoptosis.

METHODS

Morphological study, DNA gel electrophoresis, flow cytometry and fluorescin labeled Annexin V to detect apoptosis, RT-PCR to detect the gene related with apoptosis.

RESULTS

Human lung cancer A549 cells treated with docetaxel induced cell cycle arrest at G2M phase, leading to apoptosis. The morphology of A549 showed nuclear chromatine condensation and fragmentation. Typical ladder pattern of DNA fragmentation was observed. Sub-G1 peak was found by flow cytometry. Transcription of Fas gene was enhanced, while no change in c-myc and bcl-2 genes. Annexin labeling results revealed the co-existence of cell apoptosis and necrosis in docetaxel-treated A549 cells.

CONCLUSION

Docetaxel induces apoptosis and necrosis of human lung cancer. The induction of apoptosis may be related to expression of Fas.

Kinetics and mechanism for reduction of the anticancer prodrug trans,trans,trans-[PtCl2(OH)2(c-C6H11NH2)(NH3)] (JM335) by thiols

The reduction of the platinum(IV) prodrug trans,trans,trans-[PtCl2(OH)2(c-C6H11NH2)(NH3)] (JM335) by L-cysteine, DL-penicillamine, DL-homocysteine, N-acetyl-L-cysteine, 2-mercaptopropanoic acid, 2-mercaptosuccinic acid, and glutathione has been investigated at 25 degrees C in a 1.0 M aqueous perchlorate medium with 6.8 < or = pH < or = 11.2 using stopped-flow spectrophotometry. The stoichiometry of Pt(IV):thiol is 1:2, and the redox reactions follow the second-order rate law -d[Pt(IV)]/dt = k[Pt(IV)][RSH]tot, where k denotes the pH-dependent second-order rate constant and [RSH]tot the total concentration of thiol. The pH dependence of k is ascribed to parallel reductions of JM335 by the various protolytic species of the thiols, the relative contributions of which change with pH. Electron transfer from thiol (RSH) or thiolate (RS-) to JM335 is suggested to take place as a reductive elimination process through an attack by sulfur at one of the mutually trans chloride ligands, yielding trans-[Pt(OH)2(c-C6H11NH2)(NH3)] and RSSR as the reaction products, as confirmed by 1H NMR. Second-order rate constants for the reduction of JM335 by the various protolytic species of the thiols span more than 3 orders of magnitude. Reduction with RS- is approximately 30-2000 times faster than with RSH. The linear correlation log(kRS) = (0.52 +/- 0.06)-pKRSH--(2.8 +/- 0.5) is observed, where kRS denotes the second-order rate constant for reduction of JM335 by a particular thiolate RS- and KRSH is the acid dissociation constant for the corresponding thiol RSH. The slope of the linear correlation indicates that the reactivity of the various thiolate species is governed by their proton basicity, and no significant steric effects are observed. The half-life for reduction of JM335 by 6 mM glutathione (40-fold excess) at physiologically relevant conditions of 37 degrees C and pH 7.30 is 23 s. This implies that JM335, in clinical use, is likely to undergo in vivo reduction by intracellular reducing agents such as glutathione prior to binding to DNA. Reduction results in the immediate formation of a highly reactive platinum(II) species, i.e., the bishydroxo complex in rapid protolytic equilibrium with its aqua form.

[The determination of Niphensamide by UV spectrophotometry]

In this paper Uv spectrophotometry was used to determine Niphensamide. In this method, 372 +/- 1 nm was selected as a criterion for quantitative determination, and the absorptivity. E1 cm 1% = 556. The results indicated that a better linear-relationship between the absorbance and the concentration of the sample. When the concentration was ranged from 0.5 mg.L-1 to 40 mg.L-1, the correlation coefficient was 0.9999, and the mean rate of recovery reached 99.8%.

Conditioning the unconditioned response: modification of the rabbit's (Oryctolagus cuniculus) unconditioned nictitating membrane response

Conditioning-specific reflex modification (CRM) occurs when classical conditioning modifies responding to an unconditioned stimulus (US) in the absence of a conditioned stimulus (CS). Three experiments monitored rabbit nictitating (Oryctolagus cuniculus) membrane unconditioned responses to 5 intensities and 4 durations of periorbital electrical stimulation before and after CS or US manipulation. CRM occurred after 12 days of CS-US pairings but not following unpaired CS/US presentations or restraint. CRM survived CS-alone and CS/US-unpaired extinction of the conditioned response (CR) but not presentations of the US alone, although CRs remained intact. Thus, CRs could be weakened without eliminating CRM and CRM could be weakened without eliminating CRs. Data indicate CRM is a reliable, associative effect that is more than a generalized CR and may not be explained by habituation, stimulus generalization, contextual conditioning, or bidirectional conditioning.

Ecology, physiology, and phylogeny of deep subsurface Sphingomonas sp

Several new species of the genus Sphingomonas including S. aromaticivorans, S. stygia, and S. subterranea that have the capacity for degrading a broad range of aromatic compounds including toluene, naphthalene, xylenes, p-cresol, fluorene, biphenyl, and dibenzothiophene, were isolated from deeply-buried (>200 m) sediments of the US Atlantic coastal plain (ACP). In S. aromaticivorans F199, many of the genes involved in the catabolism of these aromatic compounds are encoded on a 184-kb conjugative plasmid; some of the genes involved in aromatic catabolism are plasmid-encoded in the other strains as well. Members of the genus Sphingomonas were common among aerobic heterotrophic bacteria cultured from ACP sediments and have been detected in deep subsurface environments elsewhere. The major source of organic carbon for heterotrophic metabolism in ACP deep aquifers is lignite that originated from plant material buried with the sediments. We speculate that the ability of the subsurface Sphingomonas strains to degrade a wide array of aromatic compounds represents an adaptation for utilization of sedimentary lignite. These and related subsurface Sphingomonas spp may play an important role in the transformation of sedimentary organic carbon in the aerobic and microaerobic regions of the deep aquifers of the ACP.

Galanin and NPY, two peptides with multiple putative roles in the nervous system

In the present brief overview we summarize results from several studies focusing on two neuropeptides, galanin and neuropeptide Y (NPY) in discrete neuronal systems, where they coexist with classic transmitters. On the basis of studies in different animal models we propose that these peptides may be involved in regulation of certain CNS functions and that drugs acting on their receptors may be of use in new therapeutic strategies. At the spinal level galanin and NPY are regulated in DRG neurons by nerve injury and in dorsal horn neurons by inflammation. It is possible that this leads to attenuation of pain sensitivity. Moreover, both peptides may exert trophic effects, for example to enhance regeneration. In the hypothalamic arcuate nucleus NPY and its receptors are part of the feeding circuitry, and we suggest that derangement of these NPY neurons may at least in part underlay the lethal phenotype of anorectic mice, which die 22 days postnatally after showing decreased food intake and growth retardation. Expression of NPY and NPY receptors is changed in the hippocampus of mice comparatively early after prion inoculation, indicating that this peptide system is affected in this spongiform degenerative disease in a region of importance for learning and memory. Finally, galanin is co-localized with classic monoamine transmitters in two central systems, the dorsal raphe serotonin neurons and the locus coeruleus noradrenergic neurons. In both cases galanin causes hyperpolarization (at high concentrations) and prolongs monoamine-induced outward currents (at low concentrations), thus modulating activity in two systems of importance for many brain functions including mood regulation. It may therefore be interesting to analyse to what extent drugs affecting galaninergic transmission also may be efficient in the treatment of, for example, depression.

[Clinical application of hydrogel membrane of silicone rubber for preventing adhesion in orthopedics]

Grafting hydrogels onto silicone rubber membranes were prepared by radiation technique for medical application. This material is characterized by high purity, hydrophilia, formation of stable hydrogel after water absorption, good biocompatibility, etc. Clinical application was initiated on the basis of animal experiments. The material was used in 47 cases of joint and tendon injuries, in 9 cases of rheumatoid arthritis, and in 4 other cases; totaling 60 cases. All patients were followed up for three and a half years after surgical operation. A general effectiveness of above 86% was noted.

Intracellular correlates of acquisition and long-term memory of classical conditioning in Purkinje cell dendrites in slices of rabbit cerebellar lobule HVI

Intradendritic recordings in Purkinje cells from a defined area in parasaggital slices of cerebellar lobule HVI, obtained after rabbits were given either paired (classical conditioning) or explicitly unpaired (control) presentations of tone and periorbital electrical stimulation, were used to assess the nature and duration of conditioning-specific changes in Purkinje cell dendritic membrane excitability. We found a strong relationship between the level of conditioning and Purkinje cell dendritic membrane excitability after initial acquisition of the conditioned response. Moreover, conditioning-specific increases in Purkinje cell excitability were still present 1 month after classical conditioning. Although dendritically recorded membrane potential, input resistance, and amplitude of somatic and dendritic spikes were not different in cells from paired or control animals, the size of a potassium channel-mediated transient hyperpolarization was significantly smaller in cells from animals that received classical conditioning. In slices of lobule HVI obtained from naive rabbits, the conditioning-related increases in membrane excitability could be mimicked by application of potassium channel antagonist tetraethylammonium chloride, iberiotoxin, or 4-aminopyridine. However, only 4-aminopyridine was able to reduce the transient hyperpolarization. The pharmacological data suggest a role for potassium channels and, possibly, channels mediating an IA-like current, in learning-specific changes in membrane excitability. The conditioning-specific increase in Purkinje cell dendritic excitability produces an afterhyperpolarization, which is hypothesized to release the cerebellar deep nuclei from inhibition, allowing conditioned responses to be elicited via the red nucleus and accessory abducens motorneurons.

Pairing-specific long-term depression prevented by blockade of PKC or intracellular Ca2+

Long-term depression was established in cerebellar Purkinje cells using 20 pairings of a brief, high frequency train of parallel fiber stimulation with a subsequent 100 ms depolarizing current injection. Effects were assessed on the peak amplitude of Purkinje cell excitatory post synaptic potentials (EPSPs) elicited by single parallel fiber test pulses. Intradendritically recorded Purkinje cell EPSPs exhibited long-term (>20 min) reduction in peak amplitude following paired stimulation but not if pretreated with the protein kinase C inhibitor calphostin C or iontophoretically injected with the calcium chelator EGTA. The similarity of the stimulation protocol and behavioral conditioning paradigms suggests pairing-specific long-term synaptic depression is a valuable model for understanding the cellular mechanisms underlying cerebellar cortical contributions to learning.

[Chitosan pin fixation of rabbit proximal tibia osteotomy]

Degradatable chitosan pin, 4 millimeters in diameter and 30 to 40 millimeters in length, was studied radiographically and histologically (oxytetracycline-labeling) at 3, 6, 12, 24 and 48 weeks after the implantation for fixation of a transverse proximal tibia osteotomy in fourty rabbits. The results showed that new bone formation and oxytetracycline uptake were increased 3-6 weeks after operation and the fracture was completely healed 12 weeks after operation, but in two rabbits the chitosan pin broke, in 3 weeks. Histologically, there was a massive inflammation (non-specific foreign body reaction) 3-12 weeks after implantation, which gradually subsided 24 weeks aften operation. Chitosan pin was slowly degradated in bone and was not replaced by normal tissue 48 weeks after operation. The questions to be addressed in future include how to increase the mechanical strength of chitosan pin and how to improve the characteristics of its surface.

[FTIR-PAS of rare earth coordinated compounds of Schiff base derived from vanillin and p-toluidine]

The Fourier transform infrared photoacoustic spectra (FTIR-PAS) of Schiff base derived from vanillin (3-methoxy-4-hydroxybenzaldehyde) and p-toluidine and its rare earth coordinated compounds in the 3800-200cm(-1) were measured and inverstigated. The coordinated compounds have two classes: [LnL2Cl x 3H2O]Cl2(Ln:La,Ce,Pr,Nd,Sm,Eu,Gd,Dy;L:Schiff base ligand) and [LnL2Cl2 x 2H2O] Cl x H2O(Ln:Ho,Er,Tm,Yb,Lu). In the coordinated compounds there is intermolecular hydrogen bond derived from phenolic hydroxy group. The bands at 400 and 300cm(-1) are respectively assigned to bonds M-O (water) and M-N.

Viscerosomatic interactions in the thalamic ventral posterolateral nucleus (VPL) of the squirrel monkey

In anesthetized squirrel monkeys single cell recordings were performed using tungsten microelectrodes. The responses of 29 viscerosomatoceptive and somatoceptive VPL neurons to noxious distension of the urinary bladder, the lower esophagus and the distal colon and to innocuous and noxious somatic stimuli were assessed when these stimuli were presented separately or together. Neuronal responses were defined as additive or interactive depending on the relative changes in responses to individual somatic or visceral stimuli, and on their responses during conditioning (somatic and visceral stimuli applied concurrently). In 13 neurons interactions between the somatosensory and visceral inputs could be demonstrated. The dominant interactive effect was inhibition, although facilitatory effects were seen as well (2 of 13). The magnitude or direction of the interactions seemed independent of the location of the somatic and visceral receptive fields. The mean population response of the neurons showing interactions was 4.66 spikes/s to somatic stimulation, and 0.07 spikes/s to visceral stimulation. During conditioning the mean interactive effect was -62% of the calculated additive effect. This implies that overall the somatic responses are halved during a coincident visceral stimulus. In a subgroup of the VPL neurons, which were classified as pure somatic responsive (n=14) due to their unresponsiveness during visceral stimulation alone, a third (n=5) still exhibited visceral convergence during conditioning. The latter neurons, therefore, receive visceral inputs, which function in a purely interactive (modulatory) manner. It is concluded that part of the described effects is due to competition (cross modality suppression) between the visceral and somatic inputs. We further conclude that the suppression of somatic information by noxious visceral stimuli may contribute to a more effective processing of the discriminatory aspects of nociceptive visceral information previously demonstrated in VPL.

[Quantitative determination of niphensamide by high performance liquid chromatography (HPLC)]

An HPLC method for the quantitative determination of Niphensamide in pesticide powder was developed. Column:Micropak-CH 5 microns (300 mm x 4.0 mm i.d.), mobile phase: CH3OH-H2O(1:1), detector: UV 254 nm, flow rate: 0.7 mL/min, column temperature: 25 degrees C. Under the above conditions, Niphensamide and other components were separated from each other. The method is simple, rapid, sensitive and accurate.

Activation of hPAK65 by caspase cleavage induces some of the morphological and biochemical changes of apoptosis

Apoptosis is a highly regulated form of cell death, characterized by distinctive features such as cellular shrinkage and nuclear condensation. We demonstrate here that proteolytic activation of hPAK65, a p21-activated kinase, induces morphological changes and elicits apoptosis. hPAK65 is cleaved both in vitro and in vivo by caspases at a single site between the N-terminal regulatory p21-binding domain and the C-terminal kinase domain. The C-terminal cleavage product becomes activated, with a kinetic profile that parallels caspase activation during apoptosis. This C-terminal hPAK65 fragment also activates the c-Jun N-terminal kinase pathway in vivo. Microinjection or transfection of this truncated hPAK65 causes striking alterations in cellular and nuclear morphology, which subsequently promotes apoptosis in both CHO and Hela cells. Conversely, apoptosis is delayed in cells expressing a dominant-negative form of hPAK65. These findings provide a direct evidence that the activated form of hPAK65 generated by caspase cleavage is a proapoptotic effector that mediates morphological and biochemical changes seen in apoptosis.

Conversion of dorsal from an activator to a repressor by the global corepressor Groucho

The Dorsal morphogen acts as both an activator and a repressor of transcription in the Drosophila embryo to regulate the expression of dorsal/ventral patterning genes. Circumstantial evidence has suggested that Dorsal is an intrinsic activator and that additional factors (corepressors) convert it into a repressor. These corepressors, however, have previously eluded definitive identification. We show here, via the analysis of embryos lacking the maternally encoded Groucho corepressor and via protein-binding assays, that recruitment of Groucho to the template by protein:protein interactions is required for the conversion of Dorsal from an activator to a repressor. Groucho is therefore a critical component of the dorsal/ventral patterning system.

Increased levels of cyclooxygenase-2 mRNA in the rat spinal cord after peripheral inflammation: an in situ hybridization study

Cyclooxygenase-2 (COX-2) is considered to play a major role in inflammation processes by catalyzing the production of prostaglandins (PGs). Using in situ hybridization histochemistry we studied the localization of COS-1 and COX-2 mRNA in the spinal cord and dorsal root ganglia (DRGs) after peripheral inflammation or after axotomy in the rat. No COX-2 mRNA signals were detected in the spinal cord under normal conditions, but strong expression was seen bilaterally in non-neuronal cells within the grey and white matter and along the leptomeninges and blood vessels 6 h after unilateral carrageenan injection into the hind paw, but not after peripheral nerve injury. The results suggest that COX-2 expressed in non-neuronal cells contributes to PG production in and around the spinal cord under peripheral inflammatory processes.

Viscero-somatic neurons in the primary somatosensory cortex (SI) of the squirrel monkey

Thirty-eight neurons in the primary somatosensory cortex (SI) in alpha-chloralose/Nembutal, or halothane (in N2O/O2) anesthetized squirrel monkeys were tested for responses to distention of the urinary bladder, the distal colon and the lower esophagus. Of the 38 SI neurons studied 13 were classified as visceroceptive. Eight of the 13 visceroceptive neurons responded to stimulation of a single viscus, the other five responded to two viscera. All SI neurons investigated had somatic low threshold type responses. Anesthesia was a critical factor, because 6 of 11 neurons responded to visceral stimulation only under a light halothane anesthetic level, and during moderate halothane anesthesia levels significantly more neurons exhibited visceral inputs than under alpha-chloralose/Nembutal. The results suggest that the squirrel monkey SI is involved in processing of visceral information.

Characterization of viable bacteria from Siberian permafrost by 16S rDNA sequencing

Viable bacteria were found in permafrost core samples from the Kolyma-Indigirka lowland of northeast Siberia. The samples were obtained at different depths; the deepest was about 3 million years old. The average temperature of the permafrost is -10 degrees C. Twenty-nine bacterial isolates were characterized by 16S rDNA sequencing and phylogenetic analysis, cell morphology, Gram staining, endospore formation, and growth at 30 degrees C. The majority of the bacterial isolates were rod shaped and grew well at 30 degrees C; but two of them did not grow at or above 28 degrees C, and had optimum growth temperatures around 20 degrees C. Thirty percent of the isolates could form endospores. Phylogenetic analysis revealed that the isolates fell into four categories: high-GC Gram-positive bacteria, beta-proteobacteria, gamma-proteobacteria, and low-GC Gram-positive bacteria. Most high-GC Gram-positive bacteria and beta-proteobacteria, and all gamma-proteobacteria, came from samples with an estimated age of 1.8-3.0 million years (Olyor suite). Most low-GC Gram-positive bacteria came from samples with an estimated age of 5,000-8,000 years (Alas suite).

Expression and regulation of the neuropeptide Y Y2 receptor in sensory and autonomic ganglia

The Y2 subtype of neuropeptide tyrosine (NPY) receptors (Y2R) and some neuropeptides have been studied with in situ hybridization in sensory and autonomic neurons of rat and monkey. Between 10% and 20% of the lumbar dorsal root ganglion (DRG) neuron profiles (NPs) contain Y2R mRNA in the rat and monkey. In rat DRGs Y2R mRNA is expressed in calcitonin gene-related peptide (CGRP)-positive, medium-sized, and large neurons, that is in a complementary fashion to the Y1R that is located in small CGRP neurons. In monkey DRGs Y2R mRNA is expressed mainly in small neurons. Peripheral axotomy up-regulates the Y2R in small and large DRG neurons in both species. Y2R and NPY mRNAs are colocalized in many large neurons in axotomized rat DRGs. Y2R mRNA is expressed in 50% of the NPs in the nodose ganglion with a modest increase after axotomy. Y2R mRNA is detected in a few NPs in normal rat superior cervical ganglia, with a marked increase after transection of the carotid nerves. No Y2R mRNA-positive, but many (approximately 30%) weakly Y1R mRNA-positive NPs were found in the sphenopalatine ganglion. Finally, Y2R mRNA levels increase in rat spinal motoneurons after axotomy. Thus, under normal circumstances NPY may act on Y1 and Y2Rs expressed, respectively, in small and large CGRP-positive DRG neurons in the rat. Y2R may be an important receptor in the viscero-sensory neurons. Y2Rs may be particularly important after axotomy serving as presynaptic and/or autoreceptors on rat DRG, superior cervical ganglion, and nodose ganglion neurons and as presynaptic receptors in monkey DRG neurons.

In vitro tumor growth inhibition by bispecific antibodies to human transferrin receptor and tumor-associated antigens is augmented by the iron chelator deferoxamine

Previously, a panel of mouse monoclonal antibodies (mAbs) to several tumor-associated antigens was chemically crosslinked to an IgG1 anti-human transferrin receptor antibody, 454A12. We called this new class of bispecific antibodies (BmAbs) "antigen forks" and showed that these antigen forks inhibited but did not completely prevent tumor cell growth. We speculated that the conjugates acted by heterologously crosslinking two antigens in a manner that interfered with the functions of one or both. The most effective BmAbs all shared one specificity for the human transferrin receptor. A monoclonal antibody to this receptor has been shown by others to reduce tumor cell growth when used with the iron chelator deferoxamine. When we combined our antigen forks with deferoxamine, two of five BmAbs synergized with deferoxamine to arrest tumor cell count at or below input levels. The most effective BmAbs were 317G5/454A12 (3/4) and 520C9/454A12 (5/4). mAb 317G5 recognizes a 42-kDa tumor-associated glycoprotein, and mAb 520C9 recognizes the c-erbB-2 protooncogene product. BmAb 3/4 was most effective against colorectal cancer cell line HT-29, and BmAb 5/4 was most effective against breast cancer cell line SK-BR-3. When deferoxamine and BmAb were replaced by fresh medium after a 6- or 7-day treatment period, no regrowth of tumor cells was observed during the next 4 days, although regrowth was seen if either deferoxamine or BmAb was used alone. Our results show that BmAbs with specificities for transferrin receptor and certain tumor-associated antigens effectively inhibit tumor growth in vitro. When used in combination with deferoxamine, such BmAbs may have therapeutic potential for the treatment of cancer.