Mutation in recR gene of Deinococcus radiodurans and possible involvement of its product in the repair of DNA interstrand cross-links

We previously reported that some Deinococcus radiodurans mutants are sensitive to DNA interstrand cross-linking agents but resistant to UV and gamma-rays. We isolated DNA fragments from a D. radiodurans genomic library which complemented the mitomycin C sensitivity of one of these mutants. One 3.2kb-long fragment contains an open reading frame of approximately 700bp and the deduced amino acid sequence is very homologous to other prokaryotic RecR proteins. This open reading frame in the mitomycin C-sensitive mutant strain contains a frame shift mutation at its carboxyl terminal region. These data suggest that RecR protein plays an important role in the resistance to interstrand cross-links in this bacterium.

Psychological and physical reactions on children after the Hanshin-Awaji earthquake disaster

Children who experienced the Hanshin-Awaji Earthquake Disaster were followed to ascertain how the psychological and physical reactions after this disaster changed. Changes observed in the symptoms of children at one and two years after the earthquake were compared between those who had lived in severely damaged area (level 7 on the Japan Meteorological Agency intensity scale) and those who had lived in mildly damaged area (less than 5 on the same scale). The survey was conducted using a questionnaire filled out by the children's parents. Two years after the earthquake, the children had returned to normal in terms of their physical conditions, even in the severely damaged area. However, symptoms of PTSD (Post-Traumatic Stress Disorder) such as persistent reexperiencing, persistent avoidance, and increased arousal were significantly more frequently found among children from the severely damaged area than among those from the mildly damaged area. To evaluate the psychological and physical reactions after the disaster is very important in order to support the children when large-scale disasters occur.

Mediation by platelet-activating factor of 12-hydroxyeicosatetraenoic acid-induced cytosolic free calcium concentration elevation in neutrophils

12(R)-hydroxyeicosatetraenoic acid (HETE) shows biphasic increase in cytosolic free calcium concentration ([Ca2+]i) in rabbit and human neutrophils; the initial transient phase and the continuous falling phase. 12(S)-HETE was less potent in both species. BN50739, a platelet-activating factor (PAF) receptor antagonist, inhibited both phases of 12(R)-HETE-induced [Ca2+]i rise but did not affect leukotriene B4 (LTB4)-induced [Ca2+]i rise. N-tosyl-L-phenylalanine chloromethyl ketone (TPCK), a PAF synthesis inhibitor, and manoalide, a phospholipase A2 inhibitor, reduced 12(R)-HETE-induced [Ca2+]i rise. These blockers inhibited the continuous phase of [Ca2+]i rise induced by N-formyl-methionyl-leucyl-phenylalanine (FMLP) with little effect on the initial phase. It had no significant effect on LTB4-induced [Ca2+]i rise. SC-41930, a LTB4-receptor antagonist, did not block 12-HETE-induced [Ca2+]i rise. In 12(R)-HETE-, FMLP- and LTB4-stimulated cells, accumulations of cell-associated PAF and released PAF were detected but not in unstimulated cells. BN50739 did not affect the accumulation of cell-associated PAF and release of PAF in 12(R)-HETE-stimulated cells. These results suggest that 12(R)-HETE-induced and partially, FMLP-induced, but not LTB4-induced [Ca2+]i rise are mediated by PAF, which is produced and released by stimulation of the cells by 12(R)-HETE and FMLP, respectively.

Regulation of the development of allodynia by intrathecally administered P2 purinoceptor agonists and antagonists in mice

Effects of agonists and antagonists of P2X-purinoceptors on the regulation of the development of allodynia were examined in mice; the drugs were administered intrathecally to the spinal cord. Suramin (5, 10 microg) and pyridoxalphosphate-6-azophenyl-2', 4'-disulfonic acid (PPADS), antagonists of P2X receptors, inhibited prostaglandin (PG) E(2)-induced allodynia. PPADS did not block glutamate-induced allodynia. alpha,beta-Methylene ATP (alpha, beta-meATP), an agonist of P2X receptor, elicited allodynia. alpha, beta-me ATP-induced allodynia was blocked by co-administration of alpha,beta-meATP with PPADS, MK 801 or N(omega)-nitro-L-arginine methyl ester (L-NAME). Suramin at higher doses (20, 40 microg) induced allodynia, which was inhibited by MK 801 or L-NAME. These results suggest that ATP P2X receptors in the spinal cord are involved in the regulation of tactile allodynia. Glutamate receptor and nitric oxide systems play an important role in the development of allodynia produced by alpha,beta-meATP and suramin.

Collective construction of the self and social relationships: a rejoinder and some extensions

This commentary elaborates on the basic thesis developed by Rothbaum, Pott, Azuma, Miyake, and Weisz and underscores the significance of the co-constructive process of the self and social relationship. Implications for future cultural psychological inquiry in this area are discussed.

Changes in seizure susceptibility to local anesthetics by repeated administration of cocaine and nomifensine but not GBR12935: possible involvement of noradrenergic system

We examined cross-sensitization of cocaine and synthetic local anesthetics to their seizure susceptibility after repeated administration. Seizure susceptibility of procaine and lidocaine increased after the end of two days of treatment with a subconvulsive dose of cocaine. Acute treatment with nomifensine but not GBR12935, a specific inhibitor of the dopamine transporter, facilitated lidocaine-induced convulsion. Furthermore, daily treatment with nomifensine for two days enhanced lidocaine-induced convulsion. These results suggest the possible involvement of the brain noradrenergic system in the changes in seizure susceptibility after repeated administration of some local anesthetics.

Dopamine transporter transmembrane domain polar mutants: DeltaG and DeltaDeltaG values implicate regions important for transporter functions

Polar residues in dopamine transporter (DAT) transmembrane domains (TMs) are likely to act individually and even interactively in recognizing cocaine and dopamine. We initially evaluated the effects of alanine substitution mutants that remove the polar side chains from residues in each of the 12 putative DAT TMs on the recognition of dopamine and the cocaine analog CFT. Eleven combination mutants with multiple substitutions in DAT TMs 4, 5, 7, or 11 were then selected as candidates for more detailed evaluation based on mutation effects on dopamine and cocaine analog affinities. An evaluation of Gibbs free energy changes displayed by single and combined TM mutants (DeltaG(o) and DeltaDeltaG(o)(int)) reveals three categories of potential interactions among mutants: 1) independent, noncooperative interactions (five influenced CFT and two influenced dopamine affinities), 2) synergistic influences (two for CFT and four for dopamine), and 3) complementation of influences on CFT recognition (four mutants) or on dopamine affinity (five). Combined mutations in TMs 4 and 5 yield the largest DeltaDeltaG(o)(int) values for dopamine uptake. TMs 4 and 11 mutants provide the largest DeltaDeltaG(o)(int) for CFT binding. Interactions between residues lying in DAT TMs 4 and 5 support current DAT structural models that suggest the juxtaposition of these two TMs. These data also support contributions of TM 4 and 11 residues to a polar pocket important for cocaine recognition. These candidate interactive DAT polar domains provide larger target sites for compounds that could modulate specific DAT functions than those provided by single mutations alone.

Selective inhibition of monoamine neurotransmitter transporters by synthetic local anesthetics

Synthetic local anesthetics (LAs) have been found to have cocaine-like characteristics with some psychotomimetic action, possibly through monoaminergic neurotransmission. To gain insight into the relation between LA action and monoamine transporters, we investigated the effect of synthetic LAs on neurotransmitter transporters, including monoamine transporters. We used cloned transporter cDNAs and examined transient functional expression in COS cells and stable expression in HeLa cells. Among the LAs tested, procaine and other ester-type LAs inhibited [3H]DA uptake and binding of [3H]2-beta-carbomethoxy-3-beta-(4-fluorophenyl)tropane (CFT), a cocaine analogue, in COS cells expressing rat dopamine transporter (DAT). The inhibition was concentration-dependent. The inhibitory effect on [3H]DA uptake was reversible and not dependent on pH, as observed in HeLa cells stably expressing DAT. Procaine also inhibited uptake of norepinephrine (NE) and serotonin (5-HT) by the norepinephrine transporter (NET) or serotonin transporter (SERT) expressed in COS cells. On the other hand, procaine and other LAs had little or no effect on [3H]GABA and [3H]glutamate uptake in COS cells expressing mouse GABA or rat glutamate/aspartate transporter. IC50 values for [3H]DA uptake inhibition correlated well with those for [3H]CFT binding inhibition, but not with intrinsic anesthetic potency. Kinetic analysis of monoamine uptake inhibition by procaine in COS cells expressing rat DAT, NET or SERT revealed a competitive action similar to that of cocaine. These results demonstrate that certain LAs selectively inhibit monoamine transporters. This might contribute to the cocaine-like psychotomimetic action of certain LAs.

Molecular analysis of the Deinococcus radiodurans recA locus and identification of a mutation site in a DNA repair-deficient mutant, rec30

Deinococcus radiodurans strain rec30, which is a DNA damage repair-deficient mutant, has been estimated to be defective in the deinococcal recA gene. To identify the mutation site of strain rec30 and obtain information about the region flanking the gene, a 4.4-kb fragment carrying the wild-type recA gene was sequenced. It was revealed that the recA locus forms a polycistronic operon with the preceding cistrons (orf105a and orf105b). Predicted amino acid sequences of orf105a and orf105b showed substantial similarity to the competence-damage inducible protein (cinA gene product) from Streptococcus pneumoniae and the 2'-5' RNA ligase from Escherichia coli, respectively. By analyzing polymerase chain reaction (PCR) fragments derived from the genomic DNA of strain rec30, the mutation site in the strain was identified as a single G:C to A:T transition which causes an amino acid substitution at position 224 (Gly to Ser) of the deinococcal RecA protein. Furthermore, we succeeded in expressing both the wild-type and mutant recA genes of D. radiodurans in E. coli without any obvious toxicity or death. The gamma-ray resistance of an E. coli recA1 strain was fully restored by the expression of the wild-type recA gene of D. radiodurans that was cloned in an E. coli vector plasmid. This result is consistent with evidence that RecA proteins from many bacterial species can functionally complement E. coli recA mutants. In contrast with the wild-type gene, the mutant recA gene derived from strain rec30 did not complement E. coli recA1, suggesting that the mutant RecA protein lacks functional activity for recombinational repair.

Identification and disruption analysis of the recN gene in the extremely radioresistant bacterium Deinococcus radiodurans

We isolated a radiosensitive mutant strain, KR4128, from a wild-type strain of Deinococcus radiodurans, which is known as a extremely radioresistant bacterium. The gene that restore the defect of the mutant in DNA repair was cloned, and it turned out to be the homolog of the recN gene of Escherichia coli. The recN gene encoded a protein of 58 kDa, and, in its N-terminal region, a potential ATP binding domain was conserved as expected for a prokaryotic RecN protein. An analysis of sequence of the mutant recN gene revealed a G:C to T:A transversion near the 3' end of the coding region. This alteration causes an ochre mutation, and results in the truncation of 47 amino acids from the C-terminal region of the RecN protein. The null mutant of recN gene was constructed by insertional mutagenesis, and it showed substantial sensitivities to various types of DNA damaging agents, indicating that a single defect in the recN gene can directly affect the DNA damage resistant phenotype in D. radiodurans. The recN locus of KR4128 was also disrupted and the disruptant indicated the sensitivity that was indistinguishable from its progenitor. The result indicate that the transversion in the recN gene of KR4128 cells causes a complete loss of function of the RecN protein and thus the C-terminal region of the RecN protein includes domain essential to its function.

Removal of Aromatic Hydrocarbon Compounds by Hydroxypropyl-cyclodextrin

Activated carbon has been used for the recovery and removal of benzene, toluene, and xylenes in air and water for a long time. However, removal of benzene, toluene, and xylenes from soil is very difficult. They can be removed by an increase in the apparent solubility of organic compounds in soil. The apparent solubilities of benzene, toluene, and xylene were investigated to estimate their inclusion behavior into natural cyclodextrins (CDs) and hydroxypropyl-cyclodextrins (HP-CDs) in the liquid phase. The apparent solubilities of benzene, toluene, and xylenes did not increase by adding natural CDs but did increase when HP-CDs were added. Benzene, toluene, and xylenes in a HP-CD solution depended on the relationship between the molecular diameter of benzene, toluene, and xylenes, the CD cavity size, and the 1-octanol-water partition coefficient. That of p-xylene was larger than that of o-xylene and m-xylene because of the smallest steric hindrance of p-xylene. Copyright 1999 Academic Press.

Dominant negative isoform of rat norepinephrine transporter produced by alternative RNA splicing

We have cloned from rat brain a family of alternatively spliced cDNAs from a single gene, which encodes a norepinephrine transporter (NET) having variations at the 3'-region including both coding and noncoding regions. This produces two transporter isoforms, rNETa and rNETb, which differ at their COOH termini. The rNETa isoform reveals a COOH terminus homologous to human NET and transports norepinephrine. In contrast, rNETb revealed no detectable transport function but reduced functional expression of rNETa when both isoforms were expressed in the same cell. Thus, rNETb potentially functions as a dominant negative inhibitor of rNETa activity. Co-expression of rNETb with a gamma-aminobutyric acid transporter (rGAT1), a serotonin transporter (rSERT), and a dopamine transporter (rDAT) reduced their transport activity. No reduction was found with the glutamate/aspartate transporter (rGLAST). Alternative RNA splicing of NET suggests a novel mechanism for the regulation of synaptic transmission.

Molecular cloning and characterization of rat trp homologues from brain

Identification of trp (transient receptor potential) gene from Drosophila photoreceptor and subsequent molecular cloning of the human cDNA homologues suggest its participation in capacitative calcium entry (CCE) or so called store-operated Ca2+ channel (SOC). We identified five different trp-related amplifications of reverse-transcription-polymerase chain reaction (RT-PCR) from rat brain; these corresponded to mouse trp homologues, mtrp1,3,4,5,6 and were distributed in various tissues with multiple expression levels. Two cDNAs, homologous to Drosophila trp from rat brain, designated rtrp3 and rtrp6, were isolated and characterized. By RT-PCR analysis, mRNAs of rtrp3 and rtrp6 were found to be expressed differently in brain and other tissues. In situ hybridization analysis revealed that rtrp6 mRNA was preferentially expressed in hippocampal dentate gyrus and cortical layers II and III. Expression of rat TRP3 and TRP6 in COS cells revealed an increase in CCE, as compared to that in the mock-transfected COS cells of the control. Isolation of cDNAs of rat trp gene family provides a useful model for studying mechanism of CCE.

Idiopathic peripheral neuropathy in the horse with knuckling: muscle and nerve lesions in additional cases

We have previously reported a pathological investigation of peripheral neuropathy in a horse with knuckling. This report describes details of the muscle and peripheral nerve lesions in two additional cases of light horse yearlings with knuckling. The skeletal muscles showed neurogenic atrophy characterized by scattered single angular fibers, fiber grouping, and fiber-type grouping. The severity of muscle lesions increased distally; that is, both fore- and hindleg muscles were affected more severely than cervical and dorsal muscles. In the peripheral nervous system, a number of Renaut bodies appeared to be common in the nerve fascicles. Pathological alterations indicating demyelination, remyelination and regeneration of nerve fibers were occasionally observed. The most common abnormality was myelin ovoids or myelin debris infiltrated by macrophages. Occasionally, myelinated axons were seen containing accumulations of organelles, often associated with buckling of the myelin. The myelin sheath occasionally formed axonal outpouching containing accumulations of mitochondria and dense lamellar bodies. Histochemically, intramuscular nerve fibers presented multiple arborization and collateral ramification, indicating relapsing denervation and reinnervation. Also seen were the fibers with myelin balloons or swollen segments considered as being degenerative processes. The distribution patterns of muscular lesions in the affected animals were indicative of systemic distal denervation atrophy. In addition, peripheral nervous lesions that selectively involve the distal parts of axons and an absence of abnormalities in neuronal cell bodies in the spinal cord suggest a dying-back neuropathy. It was concluded that this disease should be classified as a distal axonopathy.

Cyclic ADP-ribose induces Ca2+ release from caffeine-insensitive Ca2+ pools in canine salivary gland cells

Cyclic ADP-ribose (cADPR), a novel putative messenger of the ryanodine receptor, was examined regarding its ability to mobilize Ca2+ from intracellular Ca2+ stores in isolated cells of parotid and submandibular glands of the dog. cADPR induced a rapid and transient Ca2+ release in the digitonin-permeabilized cells of salivary glands. cADPR-induced Ca2+ release was inhibited by ryanodine receptor antagonists ruthenium red, ryanodine, benzocaine, and imperatoxin inhibitor but not by the inositol 1,4,5-trisphosphate (IP3)-receptor antagonist heparin. Thapsigargin, at a concentration of 3 to 30 microM, inhibited IP3-induced Ca2+ release, while higher concentrations were required to inhibit cADPR-induced Ca2+ release. Cross-potentiation was observed between cADPR and ryanodine or SrCl2, suggesting that cADPR sensitizes the Ca2+-induced Ca2+ release mechanism. Cyclic AMP plays a stimulatory role on cADPR- and IP3-induced Ca2+ release in digitonin-permeabilized cells. Calmodulin also potentiated cADPR-induced Ca2+ release, but inhibited IP3-induced Ca2+ release. Acetylcholine and ryanodine caused the rise in intracellular free Ca2+ concentration ([Ca2+]i) in intact submandibular and parotid cells. Caffeine did not produce any increase in Ca2+ release or [Ca2+]i rise in any preparation. ADP-ribosyl cyclase activity was found in the centrifuged particulate fractions of the salivary glands. These results suggest that cADPR serves as an endogenous modulator of Ca2+ release from Ca2+ pools through a caffeine-insensitive ryanodine receptor channel, which are different from IP3-sensitive pools in canine salivary gland cells. This system is positively regulated by cyclic AMP and calmodulin.

MPP+ toxicity and plasma membrane dopamine transporter: study using cell lines expressing the wild-type and mutant rat dopamine transporters

The Parkinsonism-inducing neurotoxin 1-methyl-4-phenylpyridinium (MPP+) causes specific cell death in dopaminergic neurons after accumulation by the dopamine transporter (DAT). COS cells, a non-neuronal cell line insensitive to high doses of MPP+, becomes sensitive to MPP+ when transfected with the rat DAT cDNA. We analyzed the bi-directional transport of MPP+ and its toxicity in several cell lines expressing wild or mutant DATs. Cell death in COS cells expressing wild DAT by exposure to MPP+ was concentration-dependent and cocaine-reversible. Increased wild DAT expression caused higher sensitivities to the toxin in HeLa cells. Although several mutant DATs demonstrated greater transport activity than the wild-type, they displayed similar or lower sensitivity to MPP+ toxicity. Reverse transport of preloaded [3H]MPP+ through DAT was facilitated in COS cells expressing certain mutant DATs, which consistently displayed less sensitivity to MPP+ toxicity. These results suggest that re-distribution of MPP+ due to influx/efflux turnover through the transporter is a key factor in MPP+ toxicity.

Tyrosine-533 of rat dopamine transporter: involvement in interactions with 1-methyl-4-phenylpyridinium and cocaine

To improve our understanding of structure-function relationships for neurotransmitter transporters, we performed site-directed mutagenesis of the rat dopamine transporter (DAT) and assessed the functions of the mutants in transiently-expressing COS cells. Tyrosine-533 of rat DAT lies in the 11th transmembrane region, where the corresponding amino acid of human DAT is phenylalanine. Alanine substitution of tyrosine-533 (Y533A) conferred an increased affinity for 1-methyl-4-phenylpyridinium (MPP+). Phenylalanine substitution of tyrosine-533 (Y533F) increased the velocity of MPP+ uptake but decreased DAT's affinity for MPP+. Cocaine's potency in inhibiting dopamine uptake was unchanged with Y533A, but increased with Y533F. Differences in the uptake kinetics and inhibitory potency of cocaine between rat and human DATs were similar to the differences observed between the wild-type and Y533F mutants DATs. Tyrosine-533 may be important for the DAT function and for species differences in transporter functions, including differential sensitivities to cocaine and 1-methyl-1,2,3,6-tetrahydropyridine (MPTP) in humans and rats.

Inhibition of Na+,K(+)-ATPase by platelet-activating factor in dog submandibular glands

Physiological stimulation of dog submandibular gland has been shown to generate platelet-activating factor (PAF). However, PAF is not released from cells in the tissue. To assess its intracellular activity, the effect of PAF on Na+,K(+)-ATPase was examined in dog submandibular gland cells. PAF inhibited Na+,K(+)-ATPase in membrane preparations, and the inhibitory effect was dependent on the protein concentration in the enzyme preparation. The inhibitory effect of a low concentration of PAF was antagonized by a PAF-receptor antagonist, BN 50,739, but at high concentrations, PAF was not antagonized. Kinetic analysis of PAF inhibition of Na+,K(+)-ATPase suggests that the inhibition of Na+,K(+)-ATPase by PAF is not due to competition by PAF at K(+)- or Na(+)-binding sites on the enzyme, but by complex inhibitory mechanisms. These results suggest that PAF may interact with specific and nonspecific site of action resulting in the inhibition of Na+,K(+)-ATPase. Ouabain increased mucin release from dog submandibular gland cells. Because Na+,K(+)-ATPase and ion exchange pathways are important in the secretory responses of acinar cells, PAF may regulate intracellularly the secretory function of acinar cells by modulating Na+,K(+)-ATPase and ionic homeostasis.

Mutation of D. radiodurans in a gene homologous to ruvB of E. coli

Following the digestion of chromosomal DNA of Deinococcus radiodurans with a restriction enzyme a partial genomic library was constructed using lambda phage as a vector. A phage clone whose DNA can complement the deficiency in a radiation-sensitive mutant of D. radiodurans was isolated. Following the subcloning using phasmid vector, a hybrid plasmid containing 1.2 kb inserted DNA was obtained. After the determination of nucleotide sequence, the deduced amino acid sequence showed close homology to RuvB protein of Escherichia coli; approximately 81% of the amino acids (310 residues in total) was homologous (152 were identical and 100 amino acids were similar). The putative protein has a conserved ATP binding domain characteristic of DNA helicases. However, we could not find an SOS promoter and ORF for RuvA protein in the sequence upstream of ruvB in contrast to the E. coli homologue. The mutant was transformed with exogenous DNA at the same rate as the wild-type cells, but it was moderately sensitive to UV, gamma-rays and to interstrand cross-linking reagents.

The Deinococcus radiodurans uvr A gene: identification of mutation sites in two mitomycin-sensitive strains and the first discovery of insertion sequence element from deinobacteria

Deinococcus radiodurans (Dr) possesses a prominent ability to repair the DNA injury induced by various DNA-damaging agents including mitomycin C (MC), ultraviolet light (UV) and ionizing radiation. DNA damage resistance was restored in MC sensitive (MC(S)) mutants 2621 and 3021 by transforming with DNAs of four cosmid clones derived from the gene library of strain KD8301, which showed wild type (wt) phenotype to DNA-damaging agents. Gene affected by mutation (mtcA or mtcB) in both mutants was cloned and its nucleotide (nt) sequence was determined. The deduced amino acid (aa) sequence of the gene product consists of 1016 aa and shares homology with many bacterial UvrA proteins. The mutation sites of both mutants were identified by analyzing the polymerase chain reaction (PCR) fragments derived from the genomic DNA of the mutants. A 144-base pair (bp) deletion including the start codon for the uvrA gene was observed in DNA of the mutant 3021, causing a defect in the gene. On the other hand, an insertion sequence (IS) element intervened in the uvrA gene of the mutant 2621, suggesting the insertional inactivation of the gene. The IS element comprises 1322-bp long, flanked by 19-bp inverted terminal repeats (ITR), and generated a 6-bp target duplication (TD). Two open reading frames (ORFs) were found in the IS element. The deduced aa sequences of large and small ORFs show homology to a putative transposase found in IS4 of Escherichia coli (Ec) and to a resolvase found in ISXc5 of Xanthomonas campestris (Xc), respectively. This is the first discovery of IS element in deinobacteria, and the IS element was designated IS2621.

Stimulation of cyclic ADP-ribose synthesis by acetylcholine and its role in catecholamine release in bovine adrenal chromaffin cells

Cyclic ADP-ribose (cADPR) is suggested to be a novel messenger of ryanodine receptors in various cellular systems. However, the regulation of its synthesis in response to cell stimulation and its functional roles are still unclear. We examined the physiological relevance of cADPR to the messenger role in stimulation-secretion coupling in cultured bovine adrenal chromaffin cells. Sensitization of Ca2+-induced Ca2+ release (CICR) and stimulation of catecholamine release by cADPR in permeabilized cells were demonstrated along with the contribution of CICR to intracellular Ca2+ dynamics and secretory response during stimulation of intact chromaffin cells. ADP-ribosyl cyclase was activated in the membrane preparation from chromaffin cells stimulated with acetylcholine (ACh), excess KCl depolarization, and 8-bromo-cyclic-AMP. ACh-induced activation of ADP-ribosyl cyclase was dependent on the influx of Ca2+ into cells and on the activation of cyclic AMP-dependent protein kinase. These and previous findings that ACh activates adenylate cyclase by Ca2+ influx in chromaffin cells suggested that ACh induces activation of ADP-ribosyl cyclase through Ca2+ influx and cyclic AMP-mediated pathways. These results provide evidence that the synthesis of cADPR is regulated by cell stimulation, and the cADPR/CICR pathway forms a significant signal transduction for secretion.

Individual and collective processes in the construction of the self: self-enhancement in the United States and self-criticism in Japan

A collective constructionist theory of the self proposes that many psychological processes, including enhancement of the self (pervasive in the United States) and criticism and subsequent improvement of the self (widespread in Japan), result from and support the very ways in which social acts and situations are collectively defined and subjectively experienced in the respective cultural contexts. In support of the theory, 2 studies showed, first, that American situations are relatively conducive to self-enhancement and American people are relatively likely to engage in self-enhancement and, second, that Japanese situations are relatively conducive to self-criticism and Japanese people are relatively likely to engage in self-criticism. Implications are discussed for the collective construction of psychological processes implicated in the self and, more generally, for the mutual constitution of culture and the self.

Inclusion of Volatile Organic Compounds into Natural Cyclodextrins and Their Branched Cyclodextrins in the Gaseous Phase

The adsorption isotherms of water, the differential heat of adsorption, and the entropy of adsorbed water were investigated to elucidate the structure of stability of cyclodextrins (CyD) and branched CyD's. The amount adsorbed on branched CyD's increased with increasing relative humidity. The steep rise in the amount adsorbed at higher relative humidities indicated that the structure of branched CyD's was affected by the water molecules at these higher relative humidities. The bonding force between alpha-CyD's and water molecules was stronger than that between their branched CyD's and water, while that between beta-CyD's and water was weaker than that between their branched CyD's and water. We have used activated carbons for the recovery of organic solvents. There are polar groups on the activated carbon surface. Therefore, the recovered organic solvents were degraded by these groups. However, such polar groups are not expected for the hydroxyl groups of the CyD's. The amounts of 1,1,1-trichloroethane, benzene, and toluene included in natural CyD's and their branched CyD's were measured. The amounts of organic solvents included in the CyD's depended upon the cavity radii and the glucosyl and maltosyl functional groups of the CyD's and the radii of the organic solvent molecules.

Stimulation of platelet-activating factor synthesis by neurotransmitters in salivary glands

Platelet-activating factor (PAF), a phospholipid mediator exhibiting potent biological activities, has been shown to stimulate amylase release from the pancreas and salivary glands. The capacity of salivary glands for PAF biosynthesis in response to stimulation has also been demonstrated. To elucidate the role of PAF in salivary glands, we studied the regulation of platelet-activating factor synthesis by the autonomic nervous system in canine salivary glands. Acetylcholine and ionomycin stimulated PAF production in dispersed cells from parotid, submandibular, and sublingual glands of dogs. Norepinephrine and phenylephrine, but not isoproterenol, also stimulated PAF production in submandibular gland cells. Norepinephrine-induced PAF production was blocked by phentolamine but not by propranolol. Acetylcholine and norepinephrine increased both the PAF production and liberation of [14C]arachidonic acid from cells pre-labeled with [14C]arachidonic acid in the presence of Ca2+ in the medium. These stimulants increased [14C]arachidonic acid liberation without the accompanying production of PAF in Ca(2+)-deprived medium. No activators or inhibitors of protein kinase C produced or affected acetylcholine-induced PAF production. Lyso-PAF:acetyl-CoA acetyltransferase was activated in the cells treated with acetylcholine, norepinephrine, isoproterenol, and 8Br-cyclic AMP. Deprivation of Ca2+ in the medium markedly reduced acetylcholine-induced activation of the transferase, but little affected norepinephrine-, isoproterenol-, and 8Br-cyclic AMP-induced activation. Dithiothreitol-insensitive cholinephosphotransferase activity was also increased by acetylcholine, norepinephrine, isoproterenol, and 8Br-cyclic AMP, and the deprivation of Ca2+ in the medium further increased the activation of the enzyme activity by these agents. These results suggest that PAF synthesis in canine salivary glands is under the control of muscarinic cholinergic and alpha-adrenergic systems via Ca(2+)-dependent remodeling pathways, and that the independent activation of either phospholipase A2 or acetyltransferase is insufficient for PAF production in submandibular gland cells, i.e., the concurrent activation of these enzymes is required.

Cellular and molecular aspects of monoamine neurotransmitter transporters

Neurotransmitter transporters terminate synaptic neurotransmission by accumulating neurotransmitters once again after release in a sodium- and chloride-dependent fashion. The availability of the cloned neurotransmitter transporters has allowed investigation into the roles of these transporters in neuronal function. Molecular biological and protein engineering studies including in vitro site-directed mutagenesis, chimera formation of several transporter clones, or epitope-tagging various regions of transporter proteins, have revealed the topology and functionally mapped the transporter proteins. Monoamine neurotransmitter transporters such as those for dopamine, norepinephrine and serotonin are of interest, since they are a target of drugs of abuse and are involved in neuronal disorders including Parkinson's disease and depression. Therefore, elucidating the molecular basis of these transporters may clarify these problems and help develop treatments with which to combat these disorders and drug abuse.

Cocaine inhibits the release of MPP+ but not dopamine through the rat dopamine transporter

Transporter-mediated release of dopamine and the parkinsonism-inducing neurotoxin 1-methyl-4-phenylpyridinium (MPP+) was examined in COS cells, a cell line derived from monkey kidney, expressing the rat dopamine transporter. The release of preloaded [3H]MPP+ but not [3H]dopamine was dose-dependently inhibited by cocaine and other compounds known as dopamine uptake inhibitor, 1-[2-(diphenylmethoxy)ethyl]-4-(3-phenylpropyl)-piperazine (GBR12,935) and nomifensine, although the uptake of both [3H]dopamine and [3H]MPP+ was sensitive to these compounds. The different sensitivity of the outward transport of dopamine and MPP+ to the uptake inhibitors might provide a clue to the identity of the specific site(s) for cocaine on the transporter.

Ca2+ entry induced by calcium influx factor and its regulation by protein kinase C in rabbit neutrophils

Extracellular application of acid extract from platelet-activating factor- or thapsigargin-treated rabbit neutrophils induced a rise of cytosolic free calcium concentration ([Ca2+]i) in neutrophils and adrenal chromaffin cells suspended in Ca(2+)-containing, but not in Ca(2+)-deficient, medium. The ability of the extract to selectively induce Ca2+ entry was also confirmed by the increase in 45Ca2+ uptake and failure to stimulate Ca2+ release in digitonin-permeabilized neutrophils. 12-O-tetradecanoylphorbol-13-acetate (TPA) inhibited the extract-induced [Ca2+]i rise in a staurosporine (ST)-sensitive fashion, neither of which had any effect on its production. SK&F 96365 and econazole also reduced extract-induced Ca2+ entry. These results suggest that a Ca2+ entry-inducible substrate (calcium influx factor) is extracted from Ca2+ store-depleted neutrophils, and that its action may be regulated by protein kinase C and certain pharmacological agents.

Role of cytokines in leukemic type growth of myelodysplastic CD34+ cells

The clonal growth of progenitor cells from myelodysplastic syndromes (MDS) can be subdivided into four growth patterns: (1) normal, (2) no growth or low plating efficiency, (3) low colony and high cluster number, and (4) normal or high colony number with a large number of clusters. The former two (1 and 2) can be referred to as nonleukemic patterns and latter two (3 and 4) as leukemic. In a search for a role for cytokines in leukemic-type growth of MDS progenitor cells, marrow CD34+ cells were purified up to 94% for 8 normal individuals and 88% for 12 MDS patients, using monoclonal antibodies and immunomagnetic microspheres (MDS CD34+ cells). The purified CD34+ cells were cultured for 14 days with various combinations of cytokines, including recombinant human macrophage colony-stimulating factor (rM-CSF), granulocyte-CSF (rG-CSF), granulocyte-macrophage-CSF (rGM-CSF), interleukin-3 (rIL-3), and stem cell factor (SCF; a ligand for c-kit) in serum-free medium. The clonal growth of MDS CD34+ cells supported by a combination of all of the above cytokines was subdivided into the two patterns of leukemic or nonleukemic, and then the role of individual or combined cytokines in proliferation and differentiation of MDS CD34+ cells was analyzed in each group. Evidence we obtained showed that SCF plays a central role in the leukemic-type growth of MDS CD34+ cells and that G-CSF, GM-CSF; and/or IL-3 synergize with SCF to increase undifferentiated blast cell colonies and clusters over that seen in normal CD34+ cells. SCF is present in either normal or MDS plasma at a level of nanograms per milliliter, and this physiologic concentration of SCF can stimulate progenitor cells. This means that progenitor cells are continuously exposed to stimulation by SCF in vivo and that MDS leukemic cells have a growth advantage over normal blast cells. This depends, at least in part, on cytokines such as G-CSF, GM-CSF, IL-3, and SCF.

Uptake and release of dopamine through the rat dopamine transporter expressed in Xenopus laevis oocyte: evaluation by voltammetric measurement of intracellular dopamine concentration

An attempt was made to evaluate the uptake and release of dopamine (DA) through the rat dopamine transporter (DAT) expressed in Xenopus laevis oocytes. A carbon electrode was placed intracellularly into the oocyte to measure directly the intracellular concentration of DA ([DA]i) by voltammetric analyzer. Oocytes injected with the rat DAT cRNA showed a rapid rise and fall of [DA]i in response to the perfusion solution in the presence and absence of DA. In the control experiment, oocytes injected with water showed no response to external DA. An increase in [DA]i which was induced in control oocytes injected with DA into cytosol was not affected by DA-free perfusion solution, suggesting that in the absence of the transporter the accumulated DA never leaked out from the cell. Thus, the bi-directional DA fluxes through the transporter were demonstrated electrochemically in real time on-line mode.

Changes in cellular proteins of Deinococcus radiodurans following gamma-irradiation

In order to examine radiation-induced proteins in an extremely radioresistant bacterium, Deinococcus radiodurans R1, changes in cellular proteins after gamma-irradiation were analysed by two-dimensional gel electrophoresis and silver staining. Nine proteins (190, 120, 87,60, 58, 52, 46, 41 and 41 kDa) were increased (or appeared) and more than 13 proteins diminished after gamma-irradiation at 6 kGy. Increase of eight proteins (except for 190-kDa protein) was prevented when the cells were irradiated in the presence of chloramphenicol. Three proteins, 87, 60 and 46 kDa, continued to be synthesized during post-irradiation incubation, and the amounts of these proteins increased with higher doses in a range of 1-12 kGy. Changes in the amount of proteins after irradiation in the R1 strain were compared with those in a moderately radioresistant mutant (rec I) and in a highly radiosensitive mutant (rec30). These three proteins were increased in both R1 and recI, but not in rec 30, suggesting that they are characteristic for radioresistant strains. In addition, from the microsequence analysis, the 46-kDa protein was found to be homologous to the EF-Tu protein of Escherichia coli, whereas the remarkable homologous sequence to the N-terminal of the 60-kDa protein was not found among the known proteins.

[Experimental study on effects of a high-sugar diet and physical exercise on serum phospholipids in young adults]

The life style of young adults has been receiving attention with a view to its improvement to prevent coronary heart diseases (CHD) later in life. In this study, to determining the influence of different life styles on the serum phospholipids level, we carried out experimental studies on the effects a high sugar diet and physical exercise on serum phospholipid levels. Considering the trend for young people to consume large quantities of carbonated drinks, in which most of the sugar is sucrose, we tested the effect of a high carbohydrate diet on one group of six healthy male subjects and did not find that it caused a significant increase in the serum phospholipids level. In another group of 108 healthy young female subjects, a mild exercise regimen results in a slight, but significant decrease in the serum phospholipid level (p < 0.01). The serum total cholesterol level of the group did not exhibit a significant change.

Changes in hepatic enzyme activities related to ethanol metabolism in mice following chronic ethanol administration

Male mice of three strains, C57BL, DBA and C3H/He, were fed on commercial food with 10% (v/v) ethanol solution as drinking liquid ad libitum for eighty days, and the changes in the activities of enzymes in the metabolic pathway of ethanol in the liver were examined. C57BL and C3H/He mice showed a preference for drinking the 10% (v/v) ethanol solution, while DBA mice did not. The ethanol intake g/g of body weight of C3H/He mice showed the highest value among all three strains and that of C57BL mice tended to show higher value than that of DBA mice. The liver weights of C57BL and C3H/He mice increased significantly following chronic ethanol administration, but that of DBA did not. The cytosolic enzyme alcohol dehydrogenase (ADH) showed no changes in any of the strains following chronic ethanol administration. The microsomal ethanol-oxidizing system (MEOS) of C57BL mice exhibited approximately 2-fold higher activity compared to that of DBA and C3H/He mice but did not increase in any strain following chronic ethanol administration. However, the microsomal aniline hydroxylase activity in the liver increased significantly in C57BL and C3H/He mice following chronic administration of ethanol. The microsomal cytochrome P-450 content also tended to slightly increase in the same strains of mice. It seemed that cytochrome P-450IIE1 was induced in the liver microsomes of these strains. Total aldehyde dehydrogenase (ALDH) activities together with high-Km ALDH activity increased markedly in the microsomes of C57BL mice and tended to increase in C3H/He mice, while it did not change in DBA mice following chronic ethanol administration. In the mitochondria of C57BL, total ALDH activities increased slightly and high-Km ALDH activities tended to increase. These mitochondrial ALDH activities of C3H/He and DBA mice tended to increase following chronic ethanol administration. The cytosolic ALDH activity showed no changes in any strain of mice following chronic ethanol administration. It seemed that in the microsomes, the activities of enzymes related to oxidation of ethanol increased in C57BL and C3H/He mice, which tended to consume a large amount of ethanol, and did not in DBA mice which tended to consume a small amount of it. It seemed that the increases in activities of enzymes related to oxidation of acetaldehyde in the microsomes and in the mitochondria were responsible for the strain difference.

Effect of balloon occluded arterial infusion of anticancer drugs on the prognosis of cervical cancer treated with radiation therapy

PURPOSE

The effect of local injection of anticancer drugs by balloon catheter, i.e., balloon occluded arterial infusion (BOAI), on the prognosis of cervical cancer treated with radiotherapy were retrospectively estimated.

METHODS AND MATERIALS

Sixty-five patients with cervical cancer (Stage I-IV) treated by irradiation were included in the study. Among the 65 cases, 2 were in Stage I, 13 in Stage II, 40 in Stage III, and 10 in Stage IV. Patients who received surgical resection were excluded. Thirty-nine patients received BOAI and 44 received brachytherapy. Twenty-six patients were not indicated for BOAI because of insufficient renal function, hepatic complications, hematological complications, and refusal from the patients. Cisplatin (0.9-1.7 mg/kg), Adriamycin (0.7-0.9 mg/kg), and Pepleomycin (0.4-0.6 mg/kg) were administered simultaneously into the bilateral internal iliac arteries by BOAI. External irradiation was given by 10 MV x-ray. Total dose administered to the regional lymph nodes by the external irradiation was 48.3 +/- 8.7 Gy. Radium was used at brachytherapy. The dose delivered by the brachytherapy at point A was 45.3 +/- 14.9 Gy. Patients without brachytherapy received 26.1 +/- 19.1 Gy of boost irradiation by the external photon beam. The survival probabilities of the patients were calculated by Kaplan-Meier method.

RESULTS

The 5-year survival rates of the Stage III patients with and without BOAI were 53 +/- 13% and 24 +/- 18%, respectively (p = 0.036). By multivariate analyses using Cox's proportional hazard model, stage and BOAI were selected as significant predictors of the prognosis. Transient bone marrow suppression was observed in about half of the patients with BOAI. No significant increase of the incidence of the late radiation damage by BOAI in rectum or in urinary bladder was observed.

CONCLUSION

Balloon occluded arterial infusion of anticancer drugs may improve the prognosis of the patients with cervical cancer without increasing the incidence of the late radiation damage. A larger scale prospective randomized study is desired.

Effect of nicotine on dopamine uptake in COS cells possessing the rat dopamine transporter and in PC12 cells

The effect of nicotine on the uptake of dopamine (DA) is not completely understood. We studied its effect on PC12 cells and on COS cells transfected with the rat DA transporter cDNA (pcDNADAT1). DA uptake by PC12 cells was inhibited by nicotine in a concentration-related fashion. Treatment of PC12 cells with nerve growth factor (NGF) increased such inhibition. This inhibitory effect was abolished by hexamethonium and mecamylamine, indicating that nicotine acted via the nicotinic acetylcholine (nACh) receptors in PC12 cells. This view is also supported by evidence that acetylcholine (ACh) reduced the uptake of DA in a hexamethonium-, but not atropine-, sensitive fashion. However, nicotine failed to inhibit DA uptake by COS cells possessing the DA transporter. These results suggest that the inhibitory effect of nicotine on DA uptake, when coupled with an nACh receptor leading to an indirect action on the transporter, may play a role in regulating extracellular concentrations of DA.

Pharmacological evidence for the possible involvement of repetitive action potentials in facilitation by GABA of catecholamine secretion in bovine adrenal chromaffin cells

1. gamma-Aminobutyric acid (GABA) evokes catecholamine (CA) secretion and enhances the stimulation-evoked CA secretion via facilitation of Ca2+ entry in a Cl(-)-dependent manner. The present study was designed to investigate further the ionic mechanism of modulation by GABA of CA secretion from adrenal medulla, using a primary culture of bovine chromaffin cells. 2. Tetrodotoxin (TTX), a voltage-sensitive Na+ channel blocker, reduced GABA-evoked CA secretion. 3. Inhibition of the sodium pump by ouabain or removal of extracellular K+ enhanced GABA-evoked CA secretion in a TTX-sensitive manner. 4. Tetraethylammonium (TEA) and cesium, which are known to block some types of K+ channels, markedly enhanced GABA-evoked CA secretion in a concentration-related fashion. TEA-induced enhancement of the GABA-evoked CA secretion was attenuated by TTX or replacement of extracellular Na+ by choline. On the other hand, ouabain accelerated the effect of TEA. 5. TEA and ouabain also enhanced GABA-induced Ca2+ influx and accumulation of cytosolic Ca2+, assessed with 45Ca2+ uptake and quin2 fluorescence. 6. Veratridine increased accumulation of cytosolic Ca2+ in a TTX-sensitive manner. GABA facilitated the veratridine-induced elevation of cytosolic Ca2+ even when the GABA-induced rise of cytosolic Ca2+ levelled off. 7. These results suggest the involvement of repetitive action potentials in modulation of GABA by Ca2+ mobilization and, as a consequence, of the CA secretion in chromaffin cells.

Regulation by protein kinase C of platelet-activating factor- and thapsigargin-induced calcium entry in rabbit neutrophils

12-O-Tetradecanoylphorbol-13-acetate (TPA) time-dependently inhibited the platelet-activating factor (PAF)-induced rise in cytosolic free calcium concentration ([Ca2+]i) in rabbit neutrophils, whereas staurosporine significantly enhanced it. Inositol 1,4,5-trisphosphate (IP3) induced Ca2+ release in digitonin-permeabilized cells but not in PAF-pretreated permeabilized cells. IP3-induced Ca2+ release was not affected by protein kinase C activators or inhibitors. In the cells pretreated with PAF and thapsigargin in Ca(2+)-deficient medium, stimulated Ca2+ entry was evoked by the subsequent addition of CaCl2. TPA inhibited the Ca2+ entry induced by PAF and thapsigargin in a staurosporine-reversible manner but not thapsigargin-induced [Ca2+]i elevation. These results suggest that protein kinase C negatively regulates PAF- and thapsigargin-induced rise in [Ca2+]i possibly by inhibiting Ca2+ store depletion-induced Ca2+ entry.

Phorbol esters alter functions of the expressed dopamine transporter

Recent elucidation of the amino acid sequences of the neurotransmitter transporters reveals several consensus sequences for phosphorylation by kinases including protein kinase C. Protein kinase C activation did modulate the function of the rat dopamine transporter expressed in COS cells. Cell treatment with the protein kinase C activator phorbol 12-myristate 13-acetate (PMA) reduced the affinity of binding of the radiolabeled cocaine analog [3H](-)-2 beta-carbomethoxy-3 beta-(4-fluorophenyl)tropane (WIN 35,428) without affecting its Bmax. The uptake of [3H]dopamine was reduced by treatment with PMA in a staurosporine-sensitive manner. Kinetic analysis revealed that the inhibitory effect of PMA on [3H]dopamine uptake was due to reduced uptake velocity and a small reduction of affinity for Na+, without changed affinity for dopamine. 1-Oleoyl-2-acetyl-sn-glycerol (OAG) mimicked these actions of PMA. These results demonstrate that activation of protein kinase C alters dopamine transporter functions in both ligand recognition and substrate translocation. These phosphorylation phenomena in vitro suggest the possibility that phosphorylation could modulate the activity of this important dopaminergic synaptic regulator under physiological conditions.

Plasmids in several strains of Deinococcus radiodurans

Deinococcus radiodurans is known as a radioresistant bacterium. For the construction of the shuttle vector, plasmids of this bacterium were isolated and investigated. At least two new plasmids in the cells of D. radiodurans MR1, KR1 and Sark were found in this experiment. However, a common plasmid among MR1, KR1 and Sark strains could not be found. These plasmids would be useful for the construction of the shuttle vector for cloning radioresistant genes of this bacterium.

Possible involvement of nitric oxide in acetylcholine-induced increase of intracellular Ca2+ concentration and catecholamine release in bovine adrenal chromaffin cells

The role of nitric oxide (NO) in neurotransmitter release was studied using bovine adrenal medullary chromaffin cells. L-Arginine and sodium nitroprusside (SNP) slightly increased the intracellular free calcium concentration ([Ca2+]i), and the effects of the agents were dependent on the presence of the extracellular Ca2+ ([Ca2+]o), but were not blocked by verapamil (30 microM) or diltiazem (30 microM). SNP enhanced the acetylcholine (ACh)-induced rise in [Ca2+]i in the presence but not in the absence of [Ca2+]o. The effects of L-arginine but not those of SNP were inhibited by N omega-nitro-L-arginine (L-NNA). L-NNA significantly reduced the ACh-induced rise in [Ca2+]i and catecholamine (CA) release, and the reduction was restored by L-arginine but not by D-arginine. These results suggest a possible involvement of NO in ACh-induced [Ca2+]i rise and CA release in bovine adrenal chromaffin cells.

Effect of 12-hydroxyeicosatetraenoic acid on cytosolic calcium in human neutrophils

12-Hydroxy-5,8,10,14-eicosatetraenoic acid (12-HETE) has been reported to be a chemoattractant for human neutrophils. To assess its cellular mechanism, we focused on the effect of 12-HETE on cytosolic Ca2+ ([Ca2+]i) and characterized the effect of 12-HETE on [Ca2+]i in human neutrophils. 12(S)- and 12(R)-HETE increased [Ca2+]i in the presence and absence of extracellular Ca2+ in a concentration-related fashion. The elevation of [Ca2+]i by 12(R)-HETE was completely abolished by pertussis toxin treatment. U-73122, a selective phospholipase C inhibitor, depressed the 12(S)- and 12(R)-HETE-induced rise in [Ca2+]i in the presence and absence of extracellular Ca2+. 12(R)-HETE resulted in the rapid production of inositol 1,4,5-trisphosphate (IP3). Furthermore, 12(R)-HETE elicited slight depolarization of neutrophils as assessed using the fluorescent dye bis-oxonol. These results provide evidence demonstrating the signal transduction pathway in human neutrophils after stimulation with 12-HETE and suggest that 12-HETE causes a rapid rise of [Ca2+]i by mobilizing Ca2+ from an IP3-sensitive intracellular Ca2+ pool in human neutrophils.

[A case with AML (M4EO) accompanied by recurrent reactive histiocytosis which showed spontaneous remission]

A 30-year-old female was admitted to our hospital complaining of high fever and fatigue. Laboratory findings showed as follows; WBC 41,500/microliter (40% of blasts), Hb 8.5g/dl, platelets 4.4 x 10(4)/microliter. Cytochemical staining of blasts was positive for peroxidase and non-specific esterase with NaF inhibition. Chromosome analysis showed 46, XX, inv (16p+,q-). AML with eosinophilia was diagnosed. During myelosuppression after remission induction therapy, she developed high fever, and did not respond to transfusions. Marrow smears showed the presence of phagocytic histiocytes consisting of 18% total nuclear cells. A diagnosis of reactive histiocytosis (RH) was made. She recovered spontaneously, but suffered two episode of recurrence during subsequent chemotherapy. Reactive histiocytosis is characterized by proliferation of histiocytes which phagocyte blood cells in immunodeficient cases, e.g. a myelosuppressive state after chemotherapy. RH causes high fever and prolonged myelosuppression. It is considered to be one of the poor prognostic factors in AML during chemotherapy, and spontaneous recovery is rare. In this report, the effect of hydrocortisone on histiocytes derived from patient marrow was also investigated in vitro.

Dopamine transporter mutants selectively enhance MPP+ transport

MPP+ (1-methyl-4-phenylpyridinium), a dopaminergic neurotoxin that provides the best available experimental model of Parkinson's disease, is selectively concentrated in dopamine neurons by the dopamine transporter (DAT). DAT also serves as a primary recognition site for cocaine. To help define selective molecular mechanisms by which MPP+ uptake occurs, we have tested dopamine transporters mutated in several residues for their abilities to accumulate dopamine and MPP+, and to bind a cocaine analog. Mutants in DAT 7th and 11th hydrophobic putative transmembrane domains increase MPP+ uptake velocity and affinity (1/KD), respectively. These mutations exert much more modest effects on dopamine uptake and have little impact on cocaine analog binding. These findings provide the first example of mutations that enhance transport and identify specific DAT amino acids selectively involved in neurotoxin uptake. They may also have implications for the feasibility of developing drugs that could specifically block accumulation of Parkinsonism-inducing neurotoxins.

12-Lipoxygenase product as an inhibitor of the action of chemoattractant peptide fMet-Leu-Phe in rat neutrophils

1. 12-Hydroxyeicosatetraenoic acid (12-HETE) has been evaluated for its capacities to modulate neutrophil migration and cytosolic Ca2+ ([Ca2+]i) using compounds prepared by chemical synthesis and tissue extract from dog gingiva. 2. 12-HETE inhibited N-formyl-Met-Leu-Phe (fMLP)-stimulated neutrophil migration in a concentration-dependent fashion. 3. The tissue extract from dog gingiva mimicked the actions of 12-HETE. 4. Although 12-HETE failed to increase [Ca2+]i, preincubation of neutrophils with 12-HETE led to a suppression of [Ca2+]i when the cells were subsequently stimulated by fMLP. 5. Again tissue extract from dog gingiva mimicked the action of 12-HETE on [Ca2+]i. 6. These results suggest the possible correlation of the inhibitory activities of 12-HETE on the regulation of neutrophil migration and Ca2+ mobilization, and this may be important for the role of 12-HETE in pathogenesis in periodontal tissues.