Dissociations between appetitive and consummatory responses by pharmacological manipulations of reward-relevant brain regions

Appetitive behaviors of rats were monitored in a runway situation following central infusions of neuroactive substances into brain areas implicated in electrical self-stimulation. Microinjections of the dopamine antagonist cis-flupentixol or the cholinergic antagonist atropine into the nucleus accumbens (Acb) severely reduced the approach speed and anticipatory shuttlebox activity while leaving the consumption of the 20% sucrose reward intact. Microinjections of GABA into the ventral tegmental area (VTA), pedunculopontine tegmental nucleus (PPTg), and oral pontine reticular nucleus (PnO) also severely disrupted approach without decreasing consumption. The highest doses of atropine into the VTA, PPTg, and PnO disrupted both consummatory and approach responses equally. The results indicate that modulation of various neurochemistries along the trajectory of the self-stimulation system has stronger effects on appetitive approach than consummatory motivation. The implications for understanding appetitive-approach motivation in the brain are discussed.

Telomere position on the cat chromosome

The telomere in the cat chromosome was detected by the fluorescence in situ hybridization method using all human telomere as a probe. In the metaphase chromosomes of cultured peripheral lymphocytes, telomere spots were observed in the terminal portions of the chromosomes. Although telomeres were confirmed in all chromosomes, the fluorescence intensity varied between the two homologues in some chromosomes.

Plasma monoamine metabolites and spontaneous recurrence of methamphetamine-induced paranoid-hallucinatory psychosis: relation of noradrenergic activity to the occurrence of flashbacks

The relationship between monoamine neurotransmitter function and spontaneous recurrence of methamphetamine (MAP) psychosis, a phenomenon known as flashbacks, was studied in a group of incarcerated women. Plasma levels of norepinephrine (NE), dopamine, 5-hydroxytryptamine, and their respective metabolites were assayed in 28 flashbackers, 19 non-flashbackers with a history of previous MAP psychosis, and 9 subjects with persistent MAP psychosis. Control data were available from 61 physically healthy prisoners (41 MAP users and 20 non-users, none of whom became psychotic). The plasma NE levels of the 28 flashbackers during flashbacks were significantly higher than levels during periods of normality, and were significantly higher than those in the MAP user and non-user controls. Plasma 3-methoxy-4-hydroxyphenylglycol (MHPG) levels during flashbacks were significantly higher than those in the user controls. The nine subjects with persistent MAP psychosis had significantly higher NE levels than the user and non-user controls. The 19 non-flashbackers had significantly higher MHPG levels than the user controls. Plasma levels of 3-methoxytyramine and dihydroxyphenylacetic acid contributed to the NE levels in the flashbackers, in contrast to the findings in the control group. Noradrenergic systems may be compromised in the flashbackers, suggesting increased vulnerability to psychotic decompensation. These findings suggest that aggravation in peripheral noradrenergic hyperactivity may be an important factor in the occurrence of flashbacks.

Molecular genetic basis of red cell markers and its forensic application

(1) The polymerase chain reaction (PCR) was used to amplify Rh-related cDNAs from erythroid cells cultured by the selective two-phase liquid culture system for human erythroid progenitors in peripheral blood. Two Rh polypeptide cDNAs have been isolated from the PCR products and tentatively designated RhPI cDNA and RhPII cDNA. Both cDNA clones have an open reading frame composed of 1251 nucleotides. The RhPI cDNA clone shows a single nucleotide substitution with no amino acid substitution compared with the published sequence. The RhPII cDNA clone differs from the above by 41 nucleotide substitutions in the open reading frame, resulting in 31 amino acid substitutions. Besides these cDNA clones, eleven and five truncated isoforms of the RhPI and RhPII cDNAs, have been isolated, respectively. (2) The promoter region of the Duffy gene was cloned by IPCR of 1.1 kb SacI fragment and the 3' flanking sequence was cloned by IPCR of 1.9 kb EcoRI fragment. The IPCR products contained the known Duffy cDNA sequence without introns. By comparing the coding area of the Duffy gene in 28 Duffy positive individuals, we elucidated that one base change that results in an amino acid substitution (GAT(Asp44)-->GGT(Gly)) is in accordance with the Fya/Fyb polymorphism. This fact proves that the Duffy cDNA and its gene encode the Duffy blood group system. (3) Two common alleles in Esterase D (EsD) polymorphism, EsD1 and EsD2 were characterized by the substitution of one amino acid (Gly-Glu) caused by the point mutation of one nucleotide (G-A). The point mutation between cDNAs of EsD1 and EsD2 alleles was detectable as restriction fragment length polymorphism (RFLP) using Ssp1. The RFLP makes it possible to determine the EsD phenotypes using DNA samples from forensic materials without EsD enzymatic activity. (4) The authors report studies on 19 pairs of donors and recipients in bone marrow transplantation. A broad range of genetic markers at 42 gene loci, including one DNA marker 11 red blood cell markers, five human lymphocyte antigen types, 12 serum protein markers, five red cell enzyme markers, and eight salivary markers was evaluated before and after BMT over about 2 months. As a result, 11 out of 42 gene loci of genetic markers in recipients were transformed into the donor type.

Dissociations between appetitive and consummatory responses by pharmacological manipulations of reward-relevant brain regions

Appetitive behaviors of rats were monitored in a runway situation following central infusions of neuroactive substances into brain areas implicated in electrical self-stimulation. Microinjections of the dopamine antagonist cis-flupentixol or the cholinergic antagonist atropine into the nucleus accumbens (Acb) severely reduced the approach speed and anticipatory shuttlebox activity while leaving the consumption of the 20% sucrose reward intact. Microinjections of GABA into the ventral tegmental area (VTA), pedunculopontine tegmental nucleus (PPTg), and oral pontine reticular nucleus (PnO) also severely disrupted approach without decreasing consumption. The highest doses of atropine into the VTA, PPTg, and PnO disrupted both consummatory and approach responses equally. The results indicate that modulation of various neurochemistries along the trajectory of the self-stimulation system has stronger effects on appetitive approach than consummatory motivation. The implications for understanding appetitive-approach motivation in the brain are discussed.

Identification of a novel exon and spliced form of Duffy mRNA that is the predominant transcript in both erythroid and postcapillary venule endothelium

The Duffy gene has been shown not to be split by introns, even in its 5' untranslated region, and to be expressed not only in erythroid but in postcapillary venule endothelium of almost every organ in the body. To further investigate the transcriptional start position in erythroid and postcapillary venule endothelium, we performed 5'-rapid amplification of cDNA ends (5'-RACE). While every positive clone of 5'-RACE encoded the identical sequence of previously identified cDNA downstream from nucleotide 203, the upstream sequences were different. The upstream sequences corresponded to the sequence from nucleotide -279 to -308/-357 in erythroblasts and from -279 to -355/-383 in lung and were regarded as comprising a novel exon. This novel exon encoded seven residues initiated with a methionine, linked to nucleotide 203 in-frame and in agreement with the GT-AG splicing rule. The major erythroid transcriptional start position was identified in human erythroleukemia cells by primer extension and in bone marrow by ribonuclease protection analysis at 34 bases upstream from the first ATG codon. Distinctively, in lung and kidney, the transcription was started at 82 bases upstream from the ATG. Both Northern blotting and reverse transcription-polymerase chain reaction followed by Southern analysis indicated a predominance of the novel spliced form of mRNA of about 50- to 200-fold comparing with the unspliced form, in every studied organ and erythroid lineage cells. The spliced form of cDNA has been transfected into a human erythroleukemic cell line, K562, and the expressed protein reacted with Duffy-specific murine monoclonal antibody Fy6. These studies indicate that the product from the spliced form of mRNA is the major product of the Duffy gene in the erythroid lineage and postcapillary venule endothelium.

[Searching for genetic markers--in the fields of forensic medicine and human genetics]

Research on genetic markers in the fields of forensic medicine and human genetics did not begin in earnest until 1968. Study of an extended family in Wakayama Prefecture resulted in the discovery of the variant Bm type in the ABO blood group system. This family of nearly 40 members composed of Group A, B, O and AB spouses and type Bm monozygotic twins provided the best research material possible. An extremely rare case of an individual with type O red blood cells but no anti-A or anti-B antibodies led to the discovery of type AmBm. Fishman and Mitsuhashi advocated the concept of immunogenetic RNA. We attempted to examine the immunogenetic RNA function by isolating RNA from the human spleen but obtained no definitive results. Many researchers had since examined the genetic markers in erythrocytes, leukocytes, serum proteins and blood cell enzymes, but research on genetic marker in saliva had not been advanced. We searched for genetic markers in the parotid saliva and developed the PmF and Ph systems. A salivary amylase variant and acid phosphatase polymorphism were also discovered. We elucidated the genetic structure and geographic gradinet of the salivary genetic markers, such as the Pa, Pb, Pr, Db and PIF systems, in Japanese. The genetic markers in the tear and saliva of mice and rats were also detected. We demonstrated RFLP polymorphism using an amylase cDNA probe. Our report was one of the first on polymorphism in the field of forensic medicine in Japan. Interest was also directed to polymorphism in platelet and we employed two-dimensional electrophoresis to establish the ThA and ThB systems which are controlled by autosomal codominant genes. Regarding the research on monoclonal antibody production and their application in forensic medicine, we cloned and produced antibodies for ABO, MN and Lewis grouping. Anti-glycopholin-A, anti-glycopholin-B and anti-glycolipid monoclonal antibodies were also produced and used to divide the red blood cell antigens roughly into three classes; the glycopholin-A (MN), glycopholin-B (Ss. Duffy Kell-Cellano, Lutheran, Diego, Xg) and the glycolipid (ABO, Lewis, P) classes. Red blood cell protein membrane proteases were also isolated from Nepenthes alata extract and lectin which are used in grouping animal blood cells. In the research on erythrocyte differentiation and erythrocyte group substance expression, we established a selective two phase liquid culture system for culturing precursor cells of peripheral erythrocytes, and demonstrated the expression of red blood cell antigens such as ABO, Rh and Duffy antigens in the early period (4 to 9 days) of Phase 2. Recently, research on identifying the genes which code for polymorphism in erythrocytes or erythrocyte enzymes is making progress. For example, a study indicated a possible relationship between an isoform of the glycophorin A gene and the MN variant. In the cDNA sequence of the Fy (a-b+) and (a + b-) types in the Duffy system, a GAT (Asp) to GGT (Gly) substitution in the codon for residual 44 was detected. Research on the Rh gene is being pursued energetically. Two clones of the Rh gene have been isolated; Rh Pl composed of 1251 bases, and Rh Pll estimated to be Ph PI with a base substitution at position 41 and an amino acid substitution at position 31. Seven isoforms of Ph Pl and 5 isoforms of Ph Pll have been obtained. The delineation of the Rh gene which contains as many as 50 types of Rh antigen genes is in progress. The red blood cell enzyme EsD system is also used commonly in the field of forensic genetics. In EsD polymorphism, type EsD1 contains G at base 569, type EsD2 contains A and type EsD1-2 shows a heterologous conjugation of G and A. Due to the development of immunosuppressive agents, bone marrow transplant can now be conducted even when the ABO and Rh systems are not compatible, as long as the HLA is compatible. In this case, all the erythrocyte polymorphic types or erythrocyte enzyme polymorphic types are transformed to t

Effects of Platycodon grandiflorum feeding on serum and liver lipid concentrations in rats with diet-induced hyperlipidemia

To study the effect of Platycodon grandiflorum (P.g.) feeding on serum and liver lipid concentrations, diet-induced hyperlipidemic rats were fed diets containing 5% and 10% P.g. powder for 3 weeks. The P.g. feeding markedly decreased both serum and liver lipid concentrations in hyperlipidemic rats. Especially, 5% P.g. diet significantly decreased the concentrations of total cholesterol and triglycerides in serum and liver as compared with those of the hyperlipidemic control group. Dietary P.g. also induced a reduction in low-density lipoprotein (LDL)-cholesterol as well as an increase in the concentration of high-density lipoprotein (HDL)-cholesterol in serum. Furthermore, the atherogenic index was also low in rats fed P.g. diet. These results indicated that dietary P.g. may have a beneficial effect on preventing hypercholesterolemia and hyperlipidemia.

Spontaneous recurrence of methamphetamine psychosis: process and monoamine neurotransmitter function

We studied the process that causes a spontaneous recurrence of methamphetamine (MAP) psychosis, a phenomenon known as flashbacks, in 41 female flashbackers by a comparison of clinical characteristics between the 41 flashbackers and 87 non-flashbackers with previous MAP psychosis. We evaluated plasma levels of monoamine metabolites in 25 of the 41 flashbackers, 19 of the 87 non-flashbackers, 9 female patients with persistent MAP psychosis and 61 physically healthy female controls. All 41 flashbackers had experienced a significantly greater frequency of threatening events and threatening paranoid-hallucinatory states than the 87 non-flashbackers during previous MAP abuse. The triggering factor was a mild fear of other persons due to the evocation of frightening images, encoded through threatening experiences during previous MAP abuse. Norepinephrine (NE) levels were significantly associated with a history of flashbacks. Plasma 3-methoxy-4-hydroxyphenylglycol (MHPG) levels were significantly higher during flashbacks and during periods of normalcy in the flashbackers, and in the non-flashbackers, than MHPG levels in the user controls. NE levels in the patients with persistent MAP psychosis were also significantly higher than NE levels in the user controls. Elevated NE levels in the flashbackers were associated with disrupted NE, 5-HT and DA turnover. Thus, MAP-induced sensitization to frightening images may have caused the flashbacks due to aggravated noradrenergic hyperactivity.

[Bladder tumor occluding diverticular orifice: a case with difficult diagnosis due to hemorrhage into diverticulum]

We experienced a case of bladder diverticular tumor with intradiverticular hemorrhage in which preoperative diagnosis was difficult. It simultaneously occurred with a bladder tumor. The patient, a 70-year-old man complained of macrohematuria and pollakisuria. The cystoscopic examination revealed a bladder tumor. The radiographic examination suggested a bladder tumor with extravesical hemorrhage. We diagnosed an invasive bladder tumor and performed radical cystectomy and ileal conduit diversion. Postoperative diagnosis was bladder tumor and diverticular tumor.

Intricate combinatorial patterns of exon splicing generate multiple Rh-related isoforms in human erythroid cells

The Rhesus (Rh) blood group system shows complex polymorphisms in the human. Some of the heterogeneity may be generated by alternative RNA splicing. For a systematic analysis of Rh-related mRNA isoforms expressed in reticulocytes, we isolated mRNA, which was then reverse transcribed and amplified by the polymerase chain reaction (PCR) to give Rh-related cDNAs of two segments of 704 bp and 975 bp. The PCR amplification of the 5'-region yielded a single PCR product, whereas a complex electrophoretic pattern of PCR bands was derived from the 3'-region. A highly reproducible ladder of multiple additional bands migrated below the PCR products corresponding to the full-size cDNAs for RhPI and RhPII and encoding two different Rh polypeptides. Eleven and five truncated isoforms of the RhPI and RhPII cDNAs, respectively, were identified in the PCR products. These isoforms appear to be generated by combinatorial splicing of six RhPI and three RhPII exons. Our results suggest that the Rh-related polypeptides consist of a mixture of RhPI and RhPII polypeptide isoforms differing at the C terminus. Multiple RNA splicing pathways are thus operative in the two Rh-related genes even within a single cell lineage of human erythroid cells.

High fat diet-induced hyperglycemia: prevention by low level expression of a glucose transporter (GLUT4) minigene in transgenic mice

High-fat intake leading to obesity contributes to the development of non-insulin-dependent diabetes mellitus (NIDDM, type 2). Similarly, mice fed a high-fat (safflower oil) diet develop defective glycemic control, hyperglycemia, and obesity. To assess the effect of a modest increase in the expression of GLUT4 (the insulin-responsive glucose transporter) on impaired glycemic control caused by fat feeding, transgenic mice harboring a GLUT4 minigene were fed a high-fat diet. Low-level tissue-specific (heart, skeletal muscle, and adipose tissue) expression of the GLUT4 minigene in transgenic mice prevented the impairment of glycemic control and accompanying hyperglycemia, but not obesity, caused by fat feeding. Thus, a small increase (< or = 2-fold) in the tissue level of GLUT4 prevents a primary symptom of the diabetic state in a mouse model, suggesting a possible target for intervention in the treatment of NIDDM.

Differences of phenotype and gene frequency by C system in canine species

The canine C blood group was determined by an agglutination reaction with a plant agglutinin extracted from the seeds of Clerodendron trichotomum (CTL). A positive agglutination reaction was classified as type C and a negative reaction as type c. In this study, the C phenotype and the gene frequency of C were examined in 377 dogs (224 purebred dogs of 29 breeds and 153 mongrel dogs) that were bred in Utsunomiya-city, Tochigi Prefecture. Phenotype C was less frequent than phenotype c in every purebred dog. A variation in C gene frequency was observed among the purebred dogs. The highest frequency of C allele was in the Yorkshire Terrier (0.202), followed by Beagle, Shiba (0.091), Maltese (0.085), Shi Tzu (0.051) and Shetland Sheepdog (0.036). The C blood group system as a genetic marker may provide useful information for bleed identification, genetic studies between breeds, and pedigree certification.

The phenotypes and gene frequencies of genetic markers in the blood of Japanese crossbred cats

The phenotypes and gene frequencies of genetic markers in 8 blood group systems were studied in Japanese crossbred cats. The gene frequency was 0.051 for Ca, 0.949 for ca, 0.484 for TFF, 0.5133 for TFs, 0.279 for GCF, 0.721 for GCs, 0.945 for PGDA, 0.055 for PGDB, 0.544 for ESD1 and 0.456 for ESD2. Genetic polymorphism was not detected in the PGM, ACP and GLO systems.

Electrophoretic analysis of bile proteins from patients with and without gallstones

Bile proteins from 82 cases with various types of gallstones (pure cholesterol stones, cholesterol stones with a small amount of other substances, mixed stones and pigment stones) and 9 controls without gallstones were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). A unique bile protein with a molecular mass of 32 kDa was identified. The 32 kDa protein could be stained on immunoblotting membranes using immunoperoxidase with concanavalin A. The 32 kDa protein was found in all controls but only in a portion (22.2-36.4%) of the patients with gallstones of various types. Following electrophoretic elution from the SDS-PAGE gels, the 32 kDa protein was analyzed by reversed phase--high-performance liquid chromatography, yielding three peaks for controls and only two peaks for patients with gallstones.

Genomic organization of the glycoprotein D gene: Duffy blood group Fya/Fyb alloantigen system is associated with a polymorphism at the 44-amino acid residue

The Duffy blood group antigen has been characterized by its roles on red blood cells: as a receptor for the malarial parasites and as a promiscuous receptor for chemokine superfamily. Recently, the Duffy blood group associated glycoprotein D (gpFy) cDNA has been cloned (Chaudhuri et al: Proc Natl Acad Sci USA 90:10793, 1993). In this report we describe the organization of genomic DNA coding for the gpFy and elucidate the molecular nature of Fya/b polymorphisms. By a Southern blotting analysis probed with gpFy cDNA, gpFy gene was shown to be composed of three DNA fragments; 1.1-kb Sac I, 1.9-kb EcoRI, and their intervening 47-bp fragments. We cloned the 1.1-kb Sac I and 1.9-kb EcoRI fragments by inverted polymerase chain reaction (IPCR) procedure. The promoter region of the gpFy gene was cloned by IPCR of 1.1-kb Sac I fragment and the 3' flanking sequence was cloned by IPCR of 1.9 kb EcoRI fragment. The both IPCR products contained on both side the known gpFy cDNA sequence without introns, as expected. Although no TATA or CCAAT boxes are present in the promoter sequence, several transcription factor binding site motifs are contained, including AP-1, HNF-5, TCF-1, ApoE B2, W-element, H-APF-1, and Sp-1. The 3' flanking region has two additional polyadenylation signals, other than that used in the cDNA, and also has an indirect and a direct repeat sequence clustered with the 5' flanking region. These facts indicate a possibility that the gpFy gene has been evolved by multiple retrotransposition events. By comparing the coding area of the gpFy gene in 28 Duffy-positive individuals, we elucidated that one base change that results in an amino acid substitution [GA-T(Asp44)-->GGT(Gly)] is in accordance with the Fya/Fyb polymorphism. This fact proves that the gpFy cDNA and its gene described in this report encode the Duffy blood group system.

Expression of an insulin-responsive glucose transporter (GLUT4) minigene in transgenic mice: effect of exercise and role in glucose homeostasis

The effects of a GLUT4 mini-transgene (containing 7 kb of 5' flanking and 1 kb of 3' flanking sequence and all exons and introns of the GLUT4 gene as well as a small foreign DNA tag) and of exercise training on expression of GLUT4 and glycemic control in mice were investigated. Transgenic mice harboring the minigene expressed < or = 2-fold the normal level of GLUT4 mRNA and protein in skeletal (gastrocnemius) muscle and adipose tissue. This modest tissue-specific increase in GLUT4 expression led to an unexpectedly rapid blood glucose clearance rate following oral glucose administration. In nontransgenic animals exercise caused a 1.5-fold increase in expression of GLUT4 mRNA and protein as well as a significant improvement of glycemic control. In transgenic animals harboring the minigene exercise increased expression of GLUT4 mRNA and protein derived from the minigene and endogenous gene and led to a further improvement of glycemic control. These findings indicate that the cis-regulatory element(s) controlling exercise-induced expression of the GLUT4 gene is located within the nucleotide sequence encompassed by the GLUT4 minigene. The fact that glycemic control is markedly improved by a relatively low level of expression of GLUT4 caused by the transfected minigene and is further enhanced by exercise in transgenic animals demonstrates that GLUT4 plays a pivotal role in glucose homeostasis in vivo. Of the effectors--i.e., cAMP, insulin, and arachidonic acid--known to down-regulate expression of GLUT4 by 3T3-L1 adipocytes in culture, only the decline in circulating arachidonate level in vivo correlated with up-regulation of GLUT4 caused by exercise.

The electrokinetic behavior of red blood cells from a patient with Tn syndrome by Doppler electrophoretic light scattering analysis

The Tn syndrome is an acquired form of persistent mixed-field polyagglutination displaying two distinct populations of Tn positive (Tn) and Tn negative (tn) red blood cells (RBCs). We investigated the electrophoretic behavior of RBCs showing polyagglutination from a patient with Tn syndrome by the doppler electrophoretic light scattering (D.E.L.S.) analysis. The mean of zeta potential of normal RBCs from ten individuals was -13.07 +/- 0.61 mV (mean +/- S.D.). The content of membrane-associated sialic acid equated with the zeta potential of RBCs. Among the proteases ficin was most effective on the zeta potential of RBCs. The zeta potential of the patient Tn RBCs and tn RBCs were -4.73 mV and -13.32 mV, respectively. Tn RBCs reduced 64.5% of zeta potential compared with tn RBCs and formed 48.8%. These results may provide some useful information for classification of Tn syndrome.

The effects of melatonin on isolation distress in chickens

Melatonin (0.1-1.0 mg/kg) reduced isolation-induced distress vocalizations (DVs) in young domestic chickens in a dose-dependent manner. This effect was unaffected by the administration of d-amphetamine (1.0 mg/kg) suggesting that melatonin's effects were not merely due to fatigue. The melatonin reduction in DVs was not naloxone reversible, indicating an action independent of the endogenous opioid system. However, chronic pretreatment with naltrexone facilitated the melatonin effect, suggesting a complex relationship between melatonin and the endogenous opioids in regulating distress vocalizations. Chickens exhibited a marked reduction in DVs when isolation chambers were darkened, suggesting endogenous, as well as exogenous, melatonin mediation of isolation distress; however; pinealectomy only partially reversed the darkness effect. Pinealectomized animals, like control animals, exhibited a reduction in DVs following melatonin treatment; however, the melatonin effect was shorter lasting. The implications that these results may have for socialization and emotional distress are discussed.

Expression of Rh blood group gene transcripts in human leukocytes

The Rh blood group system was recognized as one of the most complex polymorphisms in human. Whether or not the Rh antigens are present on human leukocytes is still an unresolved question. The expression of the Rh gene at the mRNA was analyzed in purified populations of human leukocytes by using reverse transcription and polymerase chain reaction (RT-PCR) followed by Southern blot analysis. The PCR products of the 5'-terminal region showed a single band as expected in the CD19+TCR-1 and CD14+ cells but doubtfully in the CD13+CD71- and CD190-TCR-1+ cells. On the other hand, in all these cells, the PCR products of the 3' region exhibited multiple additional bands migrating ahead of the band as expected, which showed distinctly different sets of bands in each cell. The additional bands appeared to consist of RhPI- and RhPII-cDNA splicing isoforms. These results indicated that the expression of the Rh gene is not restricted to human erythroid lineage. Additionally, it was suggested that different transcription initiation sites might be utilized preferentially for Rh gene expression.

Differential splicing of the glycophorin A mRNA

Two truncated mRNAs, in contrast to the full length of mRNA associated with the glycophorin A gene (GpA-TI, GpA-TII), were isolated from erythroid cells cultured by the selective two-phase liquid culture system for erythroid progenitors in peripheral blood from a normal individual. The GpA-TI mRNAs displayed a direct transition from exon I to exon III, so that the deletion of exon II resulted in the deletion of 33 amino acids encoded by this exon. Furthermore, the GpA-TII showed two direct transitions from exon I to exon III and from exon III to the exon V of the GpA gene. This mRNA lacked both exons II and VI, resulting in the deletion of 46 amino acids. Is is concluded that these truncated mRNAs are transcribed from the same gene as the GpA gene and correspond to splicing isoforms lacking different exons.

Suppressive effects of urine on the SOS responses induced by UV and chemical mutagens

We studied the antimutagenic effects of urine on the SOS-inducing activity of mutagenic substances by using a novel test system (umu-test) for detecting DNA damaging agents, which uses a new tester strain (Salmonella typhimurium TA1535/pSK1002). The SOS-inducing activity of chemicals was detected in terms of the level of umu operon expression by measuring beta-galactosidase activity. We first examined the effects of various amounts of urine on SOS responses caused by mitomycin C (MMC). As a result, the urine suppressed beta-galactosidase activity of MMC dose-dependently. A urine concentration of 50 microliters/ml in the medium also suppressed 89.9% of SOS response induced by 0.1 microgram/ml of PEP, 75.6% of that induced by 0.02 microgram/ml of AF2 and 60.9% of that induced by 0.1 microgram/ml of AFB1. In addition, a urine concentration of 50 microliters/ml in the medium also suppressed 85.6% of SOS response by 5 J/m2 of UV irradiation. The observed suppression seemed to be directly related to the SOS responses at a cellular level, rather than to interaction between urine and mutagens, because the urine suppressed SOS responses induced not only by various mutagens but also by UV irradiation. These results suggest that urine works as a strong antimutagen against UV and chemical substances.