Identification of a transforming activity suppressing sequence in the c-raf oncogene

Our previous study revealed that the rat c-raf was activated by a rearrangement leading to replacement of the amino-terminal half of the product. Therefore, we suggested that some sequences present in the amino-terminal half might prevent c-raf from becoming an active oncogene. To examine this possibility, we constructed a series of deletion mutants of c-raf cDNA by the random linker insertion method. By transfection of NIH3T3 cells with these mutants, a region whose deletion resulted in activation of c-raf was identified. This region is located at amino acid residues 245 to 261, immediate upstream of the kinase domain of the c-raf product and is rich in serine and threonine residues. This region includes a sequence of six amino acids, RSTSTP, which is conserved in the products of normal raf gene families of various species. This sequence is the best candidate for suppressing transforming activity of c-raf.

Peritoneal transport of beta-lactam antibiotics: effects of plasma protein binding and the interspecies relationship

In order to examine quantitatively the effect of plasma protein binding on the peritoneal transport of beta-lactam antibiotics, we employed a kinetic model based on the pore theory of transcapillary exchange. This model incorporates the changes in the volume, osmolality, and antibiotic concentration in the dialysate, so that the apparent capillary membrane permeability (Pd) and the reflection coefficient (sigma d) of an antibiotic could be assessed. Six cephalosporins (cefatrizine, cefazolin, cefpiramide, ceftazidime, ceftriaxone, cephaloridine) were used as model compounds. While the unbound fractions of these antibiotics ranged widely from 0.08 to 0.57, including linear and nonlinear protein binding, the concentration-time profiles in plasma and the peritoneal dialysate after intravenous administration in rats could be interpreted well by our model, assuming that only the unbound antibiotic is available for the peritoneal transport. The estimated Pd values were almost the same among the drugs examined. Moreover, the Pd values of cefazolin in mice, rats, and rabbits exhibited a 0.83-power dependency on the animal body weight, indicating that Pd is significantly related to the peritoneal surface area. On the other hand, the sigma d values of cefazolin were found to be almost the same among the animal species examined. Finally, the concentration-time profile of cefazolin in the dialysate after intravenous administration in a patient with end-stage renal failure was successfully predicted using the Pd value extrapolated from those of the experimental animals.

Kinetics of peritoneal drug transport in rats: an application of the pore theory of transcapillary exchange

In order to quantitatively describe the peritoneal transport of drugs, this paper proposes a kinetic model that is based on the hydrodynamic pore theory of transcapillary exchange, and incorporates an explicit description of volume and osmolality changes in the dialysate. Sulfisoxazole (SIX) and benzoic acid (BA) were used as model compounds. Following intraperitoneal administration of dialysate in rats, the osmolality, volume, and drug concentration in the dialysate were measured with respect to time. The obtained data were analyzed to give hydrodynamic parameters for solvent and a solute (including drug) by a computer-aided curve-fitting procedure according to the differential equations derived from the model. The present method, requiring no approximation of the changes in dialysate volume, made it possible to predict the concentration profiles of BA under different initial conditions of dialysate (i.e., different osmolality and volume). Solvent drag effect contributed little to the peritoneal transport of SIX and slightly to that of BA. It was also found that the peritoneal transport of BA is blood-flow limited while that of SIX is diffusion limited.

Activated N-ras oncogene in a transformant derived from a rat small intestinal adenocarcinoma induced by 2-aminodipyrido[1,2-a:3',2'-d]imidazole

DNAs from five intestinal adenocarcinomas induced by 2-aminodipyrido[1,2-a:3',2'-d]imidazole, which is present in broiled fish, were subjected to transfection assay using NIH3T3 cells as recipients. The DNA from only one adenocarcinoma induced a morphologically transformed focus. Rat N-ras sequences were detected in the primary transformant and in three tested secondary transformants. In the activated N-ras oncogene, a G----T transversion at the first letter of codon 12 was detected. The original tumor DNA did not hybridize with the oligonucleotide representing the mutated allele, but did hybridize with the one representing the normal allele. From these data we concluded either that the activation of the N-ras oncogene had occurred during the transfection or that the activated N-ras oncogene had been present in a minor population of cells in the original tumor.

The complete primary structure of the rat A-raf cDNA coding region: conservation of the putative regulatory regions present in rat c-raf

A-raf gene was first detected by low-stringent hybridization with v-raf and was reported as a possible oncogene. We have cloned rat A-raf cDNA and determined the complete nucleotide sequence over its long open reading frame. Alignment of rat A-raf- and c-raf-deduced amino acid sequences shows 59.4% homology. Both the ATP binding site and the kinase domain are conserved in A-raf as in c-raf. Furthermore, three regions highly conserved between A-raf and c-raf were identified in the 5'-half region of c-raf which has been shown to be deleted in the activated form of c-raf. These regions were speculated to be the candidates of the regulatory domain controlling the protein kinase activity of raf products. Southern blot analysis shows that genes homologous to A-raf and c-raf are present as independent loci in Drosophila melanogaster, Caenorhabditis elegans, Saccharomyces cerevisiae and Candida boidinii. A-raf was expressed in several tissues and cell line at various amounts.

Rat c-raf oncogene activation by a rearrangement that produces a fused protein

In a previous study, activated rat c-raf was detected by an NIH 3T3 cell transfection assay, and a rearrangement was demonstrated in the 5' half of the sequence of the gene. In the present study, the cDNAs of normal and activated rat c-raf were analyzed. Results showed that the activated c-raf gene is transcribed to produce a fused mRNA, in which the 5' half of the sequence is replaced by an unknown rat sequence. This mRNA codes a fused c-raf protein. The normal and activated c-raf cDNAs were each connected to the long terminal repeat of Rous sarcoma virus and transfected into NIH 3T3 cells. Only the activated form had transforming activity. We conclude that the rearrangement is responsible for the activation of c-raf.

Active H-ras and N-ras in rat fibrosarcomas induced by 1,6-dinitropyrene

The activated oncogenes in rat fibrosarcomas induced by subcutaneous injection of 1,6-dinitropyrene (1,6-DNP), an environmental mutagen-carcinogen, were examined by NIH3T3 cell transfection assay and Southern blot analysis. DNAs from two of eleven fibrosarcomas, 1,6-DNP6 and 1,6-DNP9T, induced transformants which contained rat specific repetitive sequences. Three primary transformants, obtained with DNA from 1,6-DNP6, and two secondary transformants of one of these primary transformants tested, contained rat H-ras. DNA from 1,6-DNP9T; a fourth transplant of 1,6-DNP9, also induced transformants. All the primary transformants with DNA from 1,6-DNP9T, and three secondary transformants of one of them, contained rat N-ras. The DNA from the original tumor, 1,6-DNP9, however, did not give any transformants by several transfection assays. Activation of N-ras oncogene during serial transplantations is discussed.

Cysteine-rich regions conserved in amino-terminal halves of raf gene family products and protein kinase C

The predicted amino acid sequences of rat c-raf and A-raf products were subjected to homology search against other known amino acid sequences. We found that characteristic, cysteine-rich regions present in the amino-terminal halves of c-raf and A-raf products had striking homologies with the cysteine-rich regions present in protein kinase C. These cysteine-rich regions had been shown to be deleted in the activated raf products and in the catalytically active protein kinase C produced by proteolysis. These facts suggest the significance of the cysteine-rich regions of raf products as well as those of protein kinase C in the regulation of kinase activities.

Activation of rat c-raf during transfection of hepatocellular carcinoma DNA

Rat c-raf was found to be activated in a transformant obtained with DNA of a hepatocellular carcinoma induced by 2-amino-3-methylimidazo[4,5-f]quinoline. This activated c-raf was cloned in a cosmid vector and actively transforming clones were obtained. Comparison of the restriction maps of this activated c-raf and cloned normal rat c-raf revealed a recombination in the 5'-terminal region of the activated form of this gene. The recombined DNA was shown to be actively transcribed and possibly to form a fused mRNA with c-raf, which is slightly smaller than normal c-raf mRNA. Since this recombination was not detected in the original tumor by Southern blot analysis, it presumably occurred during transfection.

Effects of various antibiotics on antibody-producing cells of mouse spleen

The inhibitory effect of various beta-lactams on antibody production in the spleen was evaluated in mice immunized with sheep red blood cells by Cunningham's method. With a few exceptions, cephem derivatives were more effective than the penicillins tested in inhibiting the production of antibodies in the spleen of mice. This tendency was especially marked with cefsulodin, cefmenoxime, cefotiam and ceftazidime. However, no effect was obtained with 6-aminopenicillanic acid or 7-aminocephalosporanic acid. Our findings suggest that the difference among various beta-lactams in inhibitory effect on antibody production resulted from the difference in activities of beta-lactams with different side chains at the 6- or 7-positions.

A new solid support for sandwich enzyme immunoassays of human immunoglobulin G

Two antibodies were prepared for use in a sandwich enzyme immunoassay of human IgG. Completely purified guinea pig anti-human IgG was labelled with beta-D-galactosidase (EC 3.2.1.23), using a heterobifunctional cross-linker named GMBS. Partially purified anti-human IgG was immobilized on a new solid support: Amino-Dylark balls. Optimal conditions for immobilizing the antibody, using glutaraldehyde as the coupling reagent, were studied in detail. With the enzyme-labelled antibody and the solid-phase anti-human IgG, a sandwich enzyme immunoassay of human IgG with a lower limit of detection at 10.5 pM (0.3 ng/tube) was developed. A comparative study of the EIA method and a laser nephelometric method showed a good correlation. The specificity of the assay was excellent: all 4 types of IgG tested showed the maximum 0.0001%; human IgA, IgM and albumin possessed the maximum 0.54% in their cross-reactivity values with human IgG.

Activation of K-ras and oncogenes other than ras family in rat fibrosarcomas induced by 1,8-dinitropyrene

Oncogenes of fibrosarcomas of rats, induced by subcutaneous injection of 1,8-dinitropyrene (1,8-DNP), were examined by NIH 3T3 cell transfection assay and Southern blot analysis. Transformants containing rat specific repetitive sequences were obtained with DNAs of 4 fibrosarcomas, 1,8-DNP1, 1,8-DNP2, 1,8-DNP3 and 1,8-DNP7. A transformant, 1,8-DNP2-2, induced by DNA of a fibrosarcoma, 1,8-DNP2, and 7 secondary transformants derived from it contained rat K-ras sequences. Another transformant, 1,8-DNP2-1, induced by the same sarcoma did not have a ras family oncogene. This indicates that the sarcoma, 1,8-DNP2, has at least 2 transforming genes. The transforming genes of 6 other transformants derived from 3 sarcomas did not contain ras family or neu transforming genes.

Activated c-raf gene in a rat hepatocellular carcinoma induced by 2-amino-3-methylimidazo[4,5-f]quinoline

A rat hepatocellular carcinoma, IQ7, induced by 2-amino-3-methylimidazo[4,5-f]quinoline (IQ) gave two transformants of NIH 3T3 cells on DNA mediated gene transfer. One of these transformants was examined further and secondary and tertiary transformants were obtained. The secondary transformant was tumorigenic in nude mice. The activated oncogene in this primary transformant was identified as rat c-raf by Southern blot analysis.

Cyclic guanidines. 17. Novel (N-substituted amino)imidazo[2,1-b]quinazolin-2 ones: water-soluble platelet aggregation inhibitors

A series of novel 1,2,3,5-tetrahydroimidazo[2,1-b]quinazolin-2-one derivatives substituted with a secondary amino group has been prepared and tested for the activities of inhibiting platelet aggregation in rats in vitro and ex vivo. Most of the compounds were found to be the potent inhibitors of platelet aggregation. Some of the active compounds were soluble in water and effective via iv infusion in rats. Structure-activity relationships have indicated that a lipophilic secondary amino group located at position 6 or 7 contributed to retention of potent activity. Among the compounds studied, 7-piperidino-1,2,3,5-tetrahydroimidazo[2,1-b]quinazolin-2- one (13 g,DN-9693) was the most favorable compound.

Activated oncogenes in a rat hepatocellular carcinoma induced by 2-amino-3-methylimidazo[4,5-f]quinoline

The presence of activated oncogenes in several rat hepatocellular carcinomas induced by 2-amino-3-methylimidazo[4,5-f]-quinoline (IQ) was examined by NIH 3T3 cell transfection assay and Southern blot analysis. In one tumor, IQ4, rat H-ras-1 and another oncogene that did not belong to the ras family were found to be activated.

Mycocerein, a novel antifungal peptide antibiotic produced by Bacillus cereus

A peptide was obtained from culture filtrates of a bacterium which was newly isolated and tentatively named Bacillus cereus SW. The peptide was composed of Asx, Ser, Glx, Leu, Tyr, Pro, and an unknown amino acid in a ratio of 2:1:1:1:1:1:1, but, unless hydrolyzed with HCI, it was ninhydrin reaction negative. The peptide effectively inhibited the growth of all fungi and yeasts so far examined, whereas it inhibited none of the bacteria tested.

A sandwich enzyme immunoassay of rabbit immunoglobulin G with an enzyme labeling method and a new solid support

A method was devised for enzyme labeling goat antibody to rabbit immunoglobulin G with beta-D-galactosidase (EC 3.2.1.23) using a heterobifunctional cross-linker, N-(gamma-maleimidobutyryloxy)-succinimide. Labeling of the purified antibody was by a continuous 2-step process and including a chromatographic purification procedure could be completed within one day. The partially purified anti-rabbit IgG was coated on Amino-Dylark cylinders, a new solid support, using glutaraldehyde as the coupling reagent. With enzyme-labeled antibody and the solid-phase anti-rabbit IgG, a sandwich enzyme immunoassay for rabbit IgG was developed with a lower limit of detection at 3.5 pM (0.1 ng/tube). The specificity of the assay was excellent and all 4 types of IgG tested showed 0.0001% or less cross-reactivity with rabbit IgG.

Dental care for severely handicapped children

Dental care for the physically and mentally handicapped ought to be a normal part of the responsibilities of the pedodontist. In the case of severe handicap, however, it may be difficult to achieve an acceptable standard of care under general practice conditions. An account is given of the regimen followed in the Tokyo Metropolitan Rehabilitation Institute for the Severely Handicapped where a team approach to dental care has been in existence for the past 10 years. Data are presented which demonstrate the incidence of dental disease in various categories of handicap and examples are given of the improvement in the quality of life of the institutionalized handicapped as a result of regular, high quality dental care.

Uterine cornual cauterization as a sterilization method

From January 1977 to December 1978, 33 cases of uterine cornual cauterization for sterilization were performed using an ultrasound scanner to locate the uterus immediately after an induced abortion at 6-8 weeks' gestation. Hysterosalpingography was performed 16 weeks postoperatively for each patient. In every case, the Fallopian tubes had been occluded.

Cyclic guanidines. 14. Imidazo[1,2-a]thienopyrimidin-2-one derivatives as blood platelet aggregation inhibitors

A series of novel 1,2,3,5-tetrahydroimidazo[1,2-a]thieno[2,3-d]-, -[3,2,-d]-, and -[3,4-d]pyrimidin-2-one derivatives has been prepared and tested for the activity of inhibiting platelet aggregation in rats in vitro and ex vivo. These compounds were synthesized through the following reactions: sodium borohydride reduction of 2,4-dichlorothienopyrimidines, followed by ethoxycarbonylmethylation and successive amination. Most of the compounds were found to be potent inhibitors of blood and platelet aggregation. Structure-activity relationships have indicated the essential contribution of the lactam structure and lipophilic substituents on the thiophene ring to the effective interaction of the compounds with a receptor site on the platelet. Among the compounds studied, 1,2,3,5,6,7,8,9-octahydro-[1]benzothieno[2,3-d]imidazo[1,2-a]pyrimidin-2-one (9m) exhibited the most favorable activity.

Effects of dextran sulfate 500 on protective responses to sublethal Trichomonas foetus infection in mice

In order to analyze the host-parasite interactions in experimental trichomoniasis, the growth of Trichomonas foetus in the peritoneal cavity and changes in the peritoneal exudate cells were followed in mice treated with dextran sulfate 500 (DS 500), a known macrophage-toxic agent. Light microscopic observation showed that DS 500 treatment induced degeneration of peritoneal macrophages within about 48 hr after the treatment and the damaged macrophages did not phagocytize the parasites, whereas peritoneal neutrophils and lymphocytes were not affected by the drug. In the DS 500-treated mice, growth of parasites in the peritoneal cavity was accelerated and a high susceptibility of the mice to T. foetus infection was observed. These results indicate that macrophages play the most important role among the peritoneal exudate cells in resistance to T. foetus infection, especially during the early stage of infection.

Chitin-binding hemagglutinin produced by Conidiobolus strains

A hemagglutinin was produced by strains of Conidiobolus which also produce beta-N-acetylglucosaminidase. Activity of the hemagglutinin was inhibited by D-glucosamine, N-acetyl-D-glucosamine, D-mannosamine, and beta-N-acetyl-D-glucosaminides but not by D-glucose, D-mannose, and alpha-N-acetyl-D-glucosaminides.