Stimulation of monoclonal antibody production by human-human hybridoma cells with an elevated concentration of potassium or sodium phosphate in serum-free medium

Potassium or sodium phosphate was found to stimulate the production of human monoclonal antibody by human-human hybridoma HB4C5. The addition of 15 mM Na-phosphate (pH 7.4) into serum-free culture medium increased the antibody production up to 4-fold, when seeded at cell density of 1×10(5) cells/ml in dishes. At the higher cell density of 5×10(5) cells/ml, K-phosphate was more effective than Na-phosphate, at the same concentration. In large-scale continuous culture, the addition of 10 mM Na-phosphate into serum-free culture medium stimulated antibody production by HB4C5 cells 6-fold.

Egg yolk lipoprotein, a new supplement for the growth of mammalian cells in serum-free medium : Egg yolk lipoprotein for serum-free growth of cells

Egg yolk lipoprotein promoted growth of a wide variety of mammalian cell lines, including plasma-cytomas and epithelial cell lines, in serum-free medium. The lipoprotein was active for cell growth when used with insulin, transferrin, ethanolamine and selenite. The most active lipoprotein fraction (YLP-pI7.5) was purified to give a single peak by chromatofocusing and gel filtration, and was homogeneous on a 0.35% agarose gel electrophoretogram. The lipoprotein was characterised as a very low density lipoprotein with a protein content of only 1.3%. This lipoprotein had an optimal concentration of 300 μg/ml (4 μg protein/ml). It was easily separable from proteinous molecules secreted into the serum-free medium by the cells, since it floated on the surface of the medium after addition of ammonium sulfate, to precipitate protein, and centrifugation. An associated structure of lipid and protein seemed to be still necessary for the lipoprotein to exhibit a growth promoting activity.

Purification and characterization of lymphocytic clonal growth factor (LCGF) derived from human-human hybridoma SH-76 cells

Human-human hybridoma SH-76 cells were found to produce a factor that supported the growth of lymphocytic cells at low densities. The factor was purified from serum-free conditioned medium of the hybridoma cells by a successive application of ammonium sulfate precipitation, DEAE-Toyopearl, TSK G3000 SW and DEAE-5PW column chromatograph. The purified factor was a 72K single protein. The factor showed marked growth stimulating effect on lymphocytic cell lines, but had no effect on the growth of human adhesive cancer cell lines. Thus, the factor is a lymphocytic clonal growth factor (LCGF), as found previously in human plasma (Miyata, 1988). The LCGF of SH-76 cells could be produced in growth factor-free RPMI medium and purified easily from the conditioned medium. The factor is inactivated by heating at over 80°C, but is much more stable than the LCGF in human plasma.

Intra-aneurysmal hemodynamics during the growth of an unruptured aneurysm: in vitro study using longitudinal CT angiogram database

BACKGROUND AND PURPOSE

The role of blood-flow biomechanics on the size, morphology, and growth of cerebral aneurysms is poorly known. The purpose of this study was to evaluate intra-aneurysmal hemodynamics before and after aneurysm growth.

MATERIALS AND METHODS

A flow-simulation study was performed in a middle cerebral artery (MCA) aneurysm with a bleb that grew after 1-year follow-up. Geometrically realistic in vitro models before and after aneurysm growth were constructed on the basis of CT angiograms. Blood-flow velocity, vorticity, and wall shear stress were obtained by using particle imaging velocimetry and laser Doppler velocimetry.

RESULTS

No significant quantitative differences were noted among the overall flow structures before and after aneurysm growth, with the exception of less vorticity in the bleb after aneurysm growth. A circulating flow pattern was seen within the aneurysm domes. A blood-flow separation was observed at the margins of the bleb. No impingement of inward flow into the enlarging bleb was noted. Before the aneurysm growth, the wall shear stress was high at the aneurysm neck and also at the margin of the bleb. The value of wall shear stress decreased in the deeper part of the bleb. This value decreased even more after the aneurysm growth.

CONCLUSIONS

Intra-aneurysmal hemodynamic structures before and after the growth of an MCA aneurysm were compared. Further investigation with a similar approach is mandatory to obtain a firm conclusion.

Horizontal and vertical distribution of estrogenic activities in sediments and waters from Tokyo Bay, Japan

Endocrine-disrupting chemicals with estrogenic activity (e.g., alkylphenols) have been detected in coastal Japan. We aimed to determine estrogenic activity in extracts of river water, seawater, sediments, and sediment cores from Tokyo Bay by in vitro gene expression assay. Fifty-one of 57 extracts had some estrogenic activity. E2 equivalents (ng E2 equivalents per gram dry weight or per liter above the limit of detection) in river water samples ranged from 0.70 to 4.01 ng/L; in seawater samples from 0.34 to 2.52 ng/L; and in surface sediments from 2.07 to 12.1 ng/g. The relationship between salinity and estrogenic activity in water samples suggested that fresh water is one source of environmental estrogens in Tokyo Bay. Fractionation of sediment extracts showed that the highest estrogenic activity was observed in the midpolar fraction. The observed activities were compared with activities mediated by known concentrations of nonylphenol, bisphenol-A, estrone, and 17beta-estradiol. In sediment collected near the sewage treatment plants, the estrogenic activity of the midpolar fraction could be explained about 34% by nonylphenol and estrone contained in this fraction. Core sediment measurements detected estrogenic activity from as far back as the 1960s. The regulations on the industrial wastewater in early 1970s would be one of the main reasons for the lower estrogenic activity in the upper section of the sediment core. The high estrogenic activities as measured in water and sediment samples from Tokyo might be restricted to certain coastal areas.

Removal of inorganic and organic mercurials by immobilized bacteria having mer-ppk fusion plasmids

Feasibility of biological mercury removal from wastewater was examined by using alginate-immobilized cells of Escherichia coli carrying mer-ppk fusion plasmid pMKB18. Immobilized cells engineered to express mercury-transport system, organomercurial lyase and polyphosphate efficiently removed organic and inorganic mercury from contaminated wastewater over a wide concentration range of mercurials, probably via intracellular accumulation mediated by ppk-specified polyphosphate. Bioaccumulation of mercury was selective compared to other metals such as Cd(2+), Pb(2+) and Cr(6+). The immobilized cells could be used repeatedly (at least three times) without large loss of mercury removal activity. From these results, it is concluded that the mer-ppk fusion plasmid and the immobilized cells are useful for simultaneous removal of organic and inorganic mercury from contaminated wastewater.

Identification of odoriferous compounds from adults of a swallowtail butterfly, Papilio machaon (Lepidoptera: Papilionidae)

Adults, particularly males, of a papilionid butterfly, Papilio machaon hippocrates, emit a fairly strong scent perceivable by humans. We have identified a variety of volatile compounds (hydrocarbons, alcohols, aldehydes, ketones, esters, and so on) from the wings and bodies of both sexes of the butterfly. Male wings secreted n-dodecane, linalool and geranylacetone as major components together with small amounts of camphene, limonene, p-cymene, 2-phenylethanol, n-hexanal, n-decanal, isoamyl acetate, p-allylanisole, 2-pyrrolidone and other characteristic volatiles. The overall profile of volatile compounds detected from male body was quite different from that of the wings. Male body was devoid of camphene, 2-phenylethanol, n-hexanal but instead contained limonene, acetoin, a sesquiterpene hydrocarbon (C15H24, methyl n-octanoate, (E,E)-hepta-2,4-dienal, and another isomer of heptadienal as principal components, of which the last four compounds were specific to the body. All these substances seem to concurrently characterize the male odor. The chemical patterns of compounds found from female wings and body were essentially the same in quality as those of male wings and body, respectively, although their quantities in females were generally smaller than in males. Females, however, had a larger amount of acetamide than males. The chemical compositions of volatiles from the fore and hind wings of males were not greatly different from each other, and every component was considered to be present on all parts of the wings. This suggests that the scent-producing organs or scent-emitting pores are widely distributed on the whole wings. EAG responses of both sexes to 12 selected compounds identified from the butterfly were not strong at a dose of 1 microg, while both sexes showed relatively stronger responses to n-nonanal, methyl n-octanoate, D-limonene and linalool at a higher dose (10 microg). Although sexual difference in EAG response was not prominent, females appeared a little more sensitive, and n-nonanal and acetoin evoked significantly higher responses from females at 1 microg.

Fulminant hepatitis type B after chemotherapy in a serologically negative hepatitis B virus carrier with acute myelogenous leukemia

We report a case of a 41-year-old man with acute myelogenous leukemia who developed fulminant hepatitis from reactivation of trace hepatitis B virus (HBV) 2 months after complete remission. Although he became positive for HB surface antigen at the onset of fulminant hepatitis, he had been negative for HBV serum markers, and only HBV DNA was detected by polymerase chain reaction (PCR) amplification on admission. The original stocks of serum samples from all blood donors were tested again for HBV DNA by PCR, and all samples were negative. This case demonstrates that testing for HBV DNA by PCR is necessary before chemotherapy, because silent HBV carriers are rare and fulminant hepatitis may be induced by chemotherapy in patients with hematologic malignancies.

Incidence of hepatitis virus infection and severe liver dysfunction in patients receiving chemotherapy for hematologic malignancies

Hepatitis virus infection through virus reactivation has a high risk of mortality in patients with hematological malignancies receiving chemotherapy. We examined the incidence of both hepatitis B virus (HBV) and hepatitis C virus (HCV) infection and severe liver dysfunction (alanine aminotransferase >ten times the normal upper limit and total bilirubin >5 mg/dl) during chemotherapy in 268 patients with hematological malignancies. Eight patients (3.0%) were infected with HBV and 22 patients (8.2%) were infected with HCV. One patient (0.4%) was infected with both HBV and HCV. HBV- or HCV-infected patients showed severe liver dysfunction at a significantly higher incidence than non-infected patients (11/31 (35.5%) vs. 0/237 (0%), p<0.0001). Furthermore, the incidence of severe liver dysfunction in HBV-infected patients was significantly higher than in HCV-infected patients (6/8 (75.0%) vs. 4/22 (18.2%), p<0.01). Three of eight HBV-infected patients were initially negative for hepatitis B surface antigen (HBsAg) by latex agglutination and became positive for HBsAg during chemotherapy. Furthermore, all three patients developed severe liver dysfunction and two developed fatal fulminant hepatitis. From an examination of the original stock of serum samples before chemotherapy, two patients were found to be positive for HBV-DNA by polymerase chain reaction (PCR). Although post-transfusion HBV infection was suspected in the one remaining patient, the cause of HBV infection could not be clarified due to the impossibility of examination in blood donors. Since HBV-infected patients develop severe liver dysfunction at a higher incidence than either patients not infected with virus or HCV-infected patients before chemotherapy for hematological malignancies, it is recommended that HBV-DNA should be tested by PCR to detect HBV marker-negative carriers and liver function tests should be carefully monitored.

Sequestration of phenanthroindolizidine alkaloids by an Asclepiadaceae-feeding danaid butterfly, Ideopsis similis

3-Demethyl-14alpha-hydroxyisotylocrebrine N-oxide was isolated along with three homologous isotylocrebrine type alkaloids from the imagines and pupae of Ideopsis similis reared on the host plant, Tylophora tanakae.

Serum-soluble c-kit levels during mobilization of peripheral blood stem cells correlate with stem cell yield

c-Kit is expressed in hematopoietic stem cells and plays an important role in hematopoiesis. In 16 patients with malignancies, serum-soluble c-Kit levels and the expressions of c-KIT messenger RNA (mRNA) and protein in peripheral blood mononuclear cells were analyzed serially during 26 courses of peripheral blood stem cell (PBSC) mobilization after granulocyte colony-stimulating factor administration following chemotherapy for PBSC harvest. Serum-soluble c-Kit levels were significantly lower in patients than in controls (179.7+/-17.7 arbitrary units [AU]/mL versus 274.5+/-18.9 AU/mL; P < .001), decreasing after chemotherapy (167.7+/-18.2 AU/mL), increasing from day 14, and peaking at day 19 (193.3+/-16.4 AU/mL). The numbers of both c-Kit+ cells and CD34+ cells and granulocyte-macrophage colony-forming units in peripheral blood peaked at day 17, following the peak of the expression of c-KIT mRNA. Serum-soluble c-Kit levels showed a significant positive correlation with the numbers of CD34+ cells in both peripheral blood and leukapheresis products (r = 0.553, P < .01, and r = 0.640, P < .001, respectively) and changed at higher levels in patients with large numbers of PBSCs versus patients with small numbers of PBSCs (P < .05). Serum-soluble c-Kit may reflect the capacity for hematopoiesis after chemotherapy and may be useful in predicting the number of PBSCs that can be mobilized and harvested after mobilization, as well as for monitoring the timing for PBSC harvest.

Uptake of 14C- and 11C-labeled glutamate, glutamine and aspartate in vitro and in vivo

To explore their potential use as in vivo tracers, the uptake of the amino acids glutamine, glutamate and aspartate, labeled with 11C or 14C, was evaluated in tumor cell aggregates, in vivo in rats and a few pilot studies with positron emission tomography (PET) in patients. The uptake in aggregates increased linearly with time, and was competitively inhibited by the same amino acids. The uptake of 14C-glutamate in carcinoid cells (BON) was inhibited by cystine but not by aspartate, contrary to the result in neuroblastoma (LAN). 6-Diazo-oxy-L-norleucine (a glutamine analogue) and Substance P had different effect on the uptake of glutamate in different cells. The metabolic fate of 14C-glutamate was evaluated with protein separation and with HPLC. The in vivo distribution in rats showed the highest uptake of 11C-glutamine and 11C-glutamate in pancreas and kidney, and of 11C-aspartate in the lung. In the human studies with PET, pancreas had the highest uptake followed by kidney with 11C-glutamate, and followed by spleen with 11C-aspartate. A primary pancreas tumour and metastases in liver were difficult to identify except in one case.

Isolation, characterization, and molecular cloning of a thermostable xylitol oxidase from Streptomyces sp. IKD472

A thermophilic bacterium, Streptomyces sp. IKD472, that can oxidize xylitol was isolated from a hot spring and was found to produce xylitol oxidase. The purified enzyme was a monomeric protein with an apparent molecular weight of 43 k as determined by sodium dodecyl sulfate polyacrylamide gel electrophoresis and gel filtration. This novel enzyme is capable of catalyzing the oxidation of one mole of xylitol to form one mole each of xylose and hydrogen peroxide. Since the V(max)K(m) value for xylitol was two and four times higher than those for galactitol and n-sorbitol, respectively, the enzyme was designated as xylitol oxidase. The enzyme was stable in the pH range from 5.5 to 10.5 and at temperatures up to 65 degrees C. The optimal temperature and pH were 55 degrees C and pH 7.5, respectively. Xylitol oxidase bound one mole of FAD as a coenzyme per mole of protein. The amino acid sequence of the NH2 terminus and the fragments obtained by lysylendpeptidase digestion of xylitol oxidase were determined for preparation of synthetic oligonucleotides as hybridization probes. A 2.8-kb chromosomal fragment hybridizing to the probes was cloned into pUC18 in Escherichia coli. The gene consists of an open reading frame of 1245 by that encodes a protein containing 415 amino acids with a molecular weight of 44,730 but without the conserved nucleotide-binding sequence, Gly-X-Gly-X-X-Gly. The amino acid sequence has 70% identity to putative oxidoreductase from Streptomyces coelicolar, 51% to sorbitol oxidase from Streptomyces sp., and 26% to L-gulonolactone oxidase from rat in terms of the overall amino acid sequence. DNA manipulation of the cloned gene in E. coli, by alteration of a strong promoter and a synthesized ribosome-binding sequence at an appropriate position, resulted in overproduction of xylitol oxidase 100 times more than that produced in the original Streptomyces sp. IKD472. The enzyme properties of recombinant xylitol oxidase were the same as those of the authentic enzyme. Stable xylitol oxidases, which allow easier quantitative analysis of xylitol, are useful for clinical applications.

Enzymatic synthesis of no-carrier-added 6-[18F]fluoro-L-dopa with beta-tyrosinase

An enzymatic synthesis of nca 6-[18F]fluoro-L-dopa has been developed. The process consists of a chemical synthesis of 4-[18F]fluorocatechol and its enzymatic reaction with beta-tyrosinase. The 4-[18F]fluorocatechol was prepared by nucleophilic aromatic substitution of the NO2 group on 6-nitroveratoraldehyde with [K/222]+18F-, followed by decarbonylation with tris(triphenylphosphine) rhodium(I) chloride and hydrolysis with hydroiodic acid. By C18 Sep-Pak purification, 4-[18F]fluorocatechol was obtained in ethanol with a radiochemical yield of 9.2%. An enzymatic reaction of 4-[18F]fluorocatechol, ammonium and pyruvate catalyzed by beta-tyrosinase in an ethanolic Tris-HCl buffer (pH 9.0) containing ascorbate gave within 5 min 6-[18F]fluoro-L-dopa with an approximate radiochemical yield of 60% without any isomers. The deproteinized reaction mixture was applied to a preparative reverse phase column, and the radiochemically and enantiomerically pure 6-[18F]fluoro-L-dopa was obtained with a radiochemical yield of 2.0% based on [18F]F- (decay-corrected). The synthesis time was 150 min from the EOB and the specific activity was > 200 GBq/micromol.

Pyrrole-2-carboxylate decarboxylase from Bacillus megaterium PYR2910, an organic-acid-requiring enzyme

Inducible pyrrole-2-carboxylate decarboxylase, which catalyzes the decarboxylation of pyrrole-2-carboxylate to pyrrole and CO2 in stoichiometric amounts, was purified from Bacillus megaterium PYR2910. The purity of the enzyme was shown by SDS/PAGE and gel-permeation HLPC. The enzyme has a molecular mass of approximately 98 kDa and consists of two identical subunits. It is highly specific for pyrrole-2-carboxylate, and also catalyzes the reverse reaction, the carboxylation of pyrrole. A unique feature of this enzyme is its requirement of an organic acid, such as acetate, propionate, butyrate or pimelate. A possible catalytic mechanism including a cofactor function of organic acid is discussed.

Interferon-induced anosmia in a patient with chronic hepatitis C

We report a patient with chronic active hepatitis C developing acute anosmia during interferon (IFN) therapy. On July 31, he began receiving 6 MU of IFN-alpha daily. On September 26, he failed to smell gas leaking from a gas cooker, so IFN therapy was discontinued. He showed no reaction on a standard olfactory acuity test. As the patient had borderline diabetes, the association of anosmia with impaired glucose tolerance cannot completely be excluded, but his anosmia was probably induced by IFN therapy, since anosmia developed 10 days after the initiation of the IFN therapy, without any deterioration of his glucose intolerance.

Synthesis of L-2,4-diamino[4-11C]butyric acid and its use in some in vitro and in vivo tumour models

L-2,4-Diamino[4-11C]butyric acid (DAB) was synthesized by an enzyme catalysed carrier added (0.1 micromol KCN) reaction of hydrogen [11C]cyanide with O-acetyl-L-serine followed by reduction. L-[11C]DAB was obtained with a radiochemical purity higher than 96% and with a decay corrected radiochemical yield of 30-40% within a 32 min reaction time. The enantiomeric excess was 98%. The uptake of L-[11C]DAB was investigated in multicellular aggregates of six different cell lines and animal tumour models. L-[11C]DAB is potentially useful for the assessment of pharmacokinetics of L-DAB in vivo for part of its evaluation as an antitumoural agent, although its use for diagnostic purposes seems limited.

Spontaneous immortalization of cultured skin fibroblasts obtained from a high-dose atomic bomb survivor

Two immortal fibroblastic cell strains (substrains) were established by culturing healthy skin cells obtained from a high-dose atomic bomb survivor (female, age 76 years, 5.14 Gy) for more than 4 years. Designated FM-U and FM-M, the two substrains share the same marker chromosome, t(5q-;6p+), but are karyotypically different, possessing hypodiploid chromosome numbers (39-43) in the former and hypertriploid (69-76) in the latter. Thus far, the two strains have passed through 117 and 156 subcultures or more than 230 and 310 cumulative population doublings, respectively, each passage requiring 4-6 days in the former and 3-4 days in the latter. In the process of immortalization, sequential rearrangement among various chromosomes presumably due to telomeric and interstitial telomeric fusions took place following the telomere shortening, particularly in the senescence and postsenescence phase cells. Of particular interest is the fact that loss of heterozygosity (LOH) of the p53 gene was demonstrated in these immortalized cell populations. In addition, the allelic patterns of the LOH of p53 differed. Further evidence indicative of infinite proliferation was demonstrated in both strains, such as the telomere elongation and the significantly low frequency of cells possessing dicentric chromosomes.

Effect of acetaminophen on stress-induced gastric mucosal lesions in rats

The effects of acetaminophen (APAP) on stress-induced gastric mucosal lesions were investigated in rats treated with water-immersion restraint stress (WIR) for 3 hours. Three-hour WIR caused both significant increase in gastric lesions in terms of ulcer index and lipid peroxide levels and decrease in prostaglandin E2 (PGE2) levels in the stomach, compared with prestress control levels. When APAP (500mg/kg) was intraperitoneally (i.p.) administered into rats 2 hours before WIR, the stress-induced changes were significantly inhibited. Whereas, three-hour WIR markedly decreased total glutathione levels in the liver, but not in the stomach and plasma and simultaneously reduced glutathione (GSH) levels in the liver and stomach were markedly decreased. In addition to the enhancement of decrease in liver total glutathione levels, APAP pretreatment caused significant decrease in gastric and plasma total glutathione levels compared with prestress control levels. Moreover, co-administration of indomethacin (5mg/kg, i.p.) with APAP almost abolished the protective effects of APAP against the stress-induced ulceration. These results suggest that APAP may protect gastric mucosa from stress-induced ulceration, probably through the promoted production of PGE2 in the gastric mucosa without restoring glutathione levels.

Infantile spasms with predominantly unilateral cerebral abnormalities

To investigate the pathogenesis of infantile spasms, 12 children underwent a combination of neurophysiologic and neuroimaging studies including brainstem evoked potentials and single photon emission computed tomography with 99mTcHMPAO. Three of the children had localized cerebral abnormalities on neuroimaging, i.e. right frontotemporal cortical microdysgenesis, left frontotemporal polymicrogyria, and right parietooccipitotemporal porencephalic cyst. Neurophysiologic studies also indicated that a single cerebral hemisphere was predominantly involved, while the other hemisphere and the brainstem were relatively spared, a result compatible with the clinical findings of hemiparesis and hemiconvulsion. In these three patients, administration of carbamazepine was followed by marked improvement of the clinical and electroencephalographic findings. Our results suggest that a combination of noninvasive examinations can distinguish a particular subtype of infantile spasms associated with a localized cerebral abnormality and responsive to carbamazepine.

[Infantile spasms with localized cerebral lesion detected by 99mTcHMPAO-SPECT]

We experienced a 6-month-old girl with infantile spasms who had localized cerebral lesion detected by 99mTcHMPAO-SPECT. She was born vaginally after a full term uncomplicated delivery with a birth weight of 3,100 g. She developed emprosthotonic spasms with series formation and EEG showed asymmetric periodic hypsarrhythmia which was predominant in the right hemisphere. While MRI could not detected any focal lesion, 99mTcHMPAO-SPECT disclosed hypoperfusion at the right anterior temporal and frontal areas. Although vitamin B6, clonazepam and sodium valproate were administered with no remarkable benefit, the treatment with ACTH-Z or carbamazepine resulted in cessation of spasms and improvement of the EEG findings. Consequently, the study with 99mTcHMPAO-SPECT was useful to clarify the pathology of infantile spasms, and we concluded that a patient with localized cerebral lesions should be given carbamazepine.

No enhancement by nitric oxide of glutamate release from P2 and P3 synaptosomes of rat hippocampus

Effects of nitric oxide on glutamate (Glu) release in long-term potentiation (LTP) were investigated by superfusion of conventional (P2) and large (P3) synaptosomes prepared from the rat hippocampus. Basal releasing rates of endogenous Glu from P2 and P3 fractions were 103.6 and 85.2 pmol/min/mg protein, respectively. Exposure to a depolarizing concentration of KCl (30 mM) evoked 3.58- and 4.52-fold increases in releasing rates of Glu from P2 and P3 fractions, respectively. Although the perfusion with sodium nitroprusside (NP, 10(-3) M), a nitric oxide-releasing agent, failed to augment the K(+)-evoked releases of Glu from P2 and P3 synaptosomes, NP enhanced that from slices of the hippocampus by 39% without changing basal release. Similarly, 8-bromoguanosine 3':5'-cyclic monophosphate (10(-4) M) increased the K(+)-evoked release of Glu from slices by 30%, but not from either synaptosomes. When synaptosomes were prepared from the hippocampus which was pretreated with two trains of electrical field stimulation (100 Hz, 0.1 ms, for 2 s), K(+)-evoked releases of Glu from P2 and P3 synaptosomes were increased by 15% and 23%, respectively. Although nitric oxide is postulated to function as a retrograde messenger to maintain LTP, present results suggest that nitric oxide may not directly act upon nerve terminals to enhance glutamate release, but that interventions of glias and short neurons may be involved in the presynaptic mechanism of LTP.

Effects of taurine on depolarization-evoked release of amino acids from rat cortical synaptosomes

Effects of taurine on endogenous aspartic acid (Asp), glutamic acid (Glu) and gamma-aminobutyric acid (GABA) release has been investigated using synaptosomes prepared from rat cerebral cortex. Although basal release of these amino acids was not affected, taurine inhibited KCl (30 mM)-evoked overflow of Asp, Glu and GABA in a concentration-dependent manner with potencies (IC50) of 1 microM, 0.8 microM and 5 nM, respectively. Taurine (10 microM) maximally inhibited K(+)-evoked Asp, Glu and GABA overflow by 28, 37 and 65%, respectively. Phaclofen (10 microM, a GABAB receptor antagonist), but not bicuculline (10 microM, a GABAA receptor antagonist), counteracted the inhibition of GABA overflow, although the inhibition of Asp and Glu overflow was not attenuated. These data suggest that taurine may inhibit GABA release through the activation of presynaptic GABAB autoreceptors and, at high concentration, also act on Asp- and Glu-nerve terminals to regulate release of excitatory amino acids in rat cortex.

Partial purification and characterization of immunoglobulin production stimulating factor derived from Namalwa cells

We screened for immunoglobulin (Ig) production stimulating factor (IPSF) which enhanced Ig production of human-to-human hybridomas in serum-free culture, and found that culture supernatant and lysate of human lymphoblastoid Namalwa cells stimulated proliferation and Ig production of human-to-human hybridoma HB4C5 cells. The IPSF in Namalwa lysate was partially purified with DEAE-Toyopearl 650M, hydroxylapatite and Superose 6HR 10/30 column chromatographies. The partially purified IPSF was a macromolecule of about 500,000 dalton containing 72,000 dalton protein as a major component. The activity was stable at pH 6 to 12, but inactivated partially by heating over 40 degrees C (60% decrease) and completely by trypsin digestion. These results suggest that the IPSF activity is due to its protein and heat-stable components. The Namalwa IPSF stimulated proliferation of human-to-human hybridomas but not that of mouse-to-mouse hybridomas. The IPSF also stimulated Ig production of human-to-human hybridomas derived from NAT-30 cells, but not that of other human-to-human or mouse-to-mouse hybridomas. NAT-30 is a human fusion partner derived from Namalwa cells. These results suggest that the Namalwa IPSF is an autocrine factor that stimulates proliferation and Ig production of hybridomas derived from NAT-30 cells.

Algal phycocyanins promote growth of human cells in culture

The growth-promoting substances in a non-dialyzable extract of Synechococcus elongatus var. on RPMI 8226 cells (a human myeloma cell line) were separated by gel filtration and ion exchange chromatography. By gel filtration with Sepharose 4B, the dialyzate was separated into two fractions. One fraction was green-colored (P-1) and the other was blue-colored (P-2). The P-2 fraction had a higher growth-promoting activity than P-1. By ion exchange chromatography, the P-2 fraction was separated into two blue-colored fractions of phycocyanin and allophycocyanin. Both biliproteins promoted the growth of RPMI 8226 cells; however, allophycocyanin was more active than phycocyanin.

Production of human-human hybridomas secreting monoclonal antibodies reactive to breast cancer cell lines

We produced human-human hybridomas by fusing lymph node lymphocytes of breast cancer patients with a fusion partner, HO-323 cells, in the presence of 50% polyethylene glycol, and screened hybridomas producing monoclonal antibody (MoAb) reactive to a breast cancer cell line, MCF-7. Among 11 hybridomas secreting IgM reactive to MCF-7, four hybridomas (H15A3, H15F2, K15B4, and K15C3) produced IgM reacting specifically to breast cancer cell lines (MCF-7 and HBC-5). Among them, H15A3 proliferated in a serum-free (RDF) medium supplemented with insulin, transferrin, ethanolamine, selenium, and endothelial cell growth supplement, as fast as in 10% FCS-RDF medium. According to transfer blotting analysis, the H15F2 MoAb reacted with a 40,000 dalton antigen in MCF-7 cells.

Characterization and applications of lymphocytic clonal growth factor in human plasma

Human plasma was found to contain a macromolecular protein which can grow even a single cell of human lymphocytic cell lines (B-lymphoblastoid cell line HO-323-3 and T-lymphoblastoid cell line CCRF-CEM) and human-human hybridoma clones (SH-9, SU-1 and HB4C5) in a dish, but it has no effect on the growth of epithelial cell lines (lung cancer cell lines PC-8, QG-56 and QG-90). The proliferating activity for lymphocytic cell lines was gradually decreased at 4 or -20°C and dramatically decreased by heating at more than 60°C for 15 min. From human plasma, active fractions were purified by a successive application of Ca(2+) treatment, ammonium sulfate fractionation, DEAE-5PW column chromatography (FPLC) at pH 7.6. These active fractions were divided into at least three proteins by DEAE-5PW chromatography at pH 8.5 and chromatofocusing. These purified factors, named lymphocytic clonal growth factors (LCGFs), had similar molecular weights of about 600 K and each factor consisted of a 180 K and two 210 K subunits associated with hydrogen bondings. By the addition of 5 μg/ml of each factor into culture media, incidences of human-human hybridomas and cloning efficiencies of the hybridomas increased several-fold.

Human hybrid immunoglobulin M containing immunoglobulin A

Some hybridoma clones made by fusion of a human lymphoblastoid cell line, HO323 with human B lymphocytes, secreted not only IgA but also IgM-like immunoglobulin molecules. The IgM-like immunoglobulin had a molecular size of 900 K which corresponded to that of IgM. Immunochemical analyses revealed that the IgM-like immunoglobulin contained two monomeric IgA and three monomeric IgM molecules. In the IgA moieties, half of original light chains were replaced with kappa chains derived from the IgM, and vice versa.

Specificity of anti-polynucleotide monoclonal antibodies from human-human hybridomas

Nine human-human hybridoma clones, secreting monoclonal antibodies reactive with nucleic acids, were generated by fusing with lymphocytes of lung cancer or systemic lupus erythematosus patients. These hybridoma antibodies were classified into 5 types, in terms of reactivities with DNA, RNA, various synthetic nucleic acids and cardiolipin. Hybridoma clone SU-1 secreted antibody reacting with dsDNA, ssDNA and RNA (type I). Clone HL-321 did not react with these, but with poly (dT), poly (I) and poly (G) (type II). Clone HL-349 was reactive with almost all nucleic acids tested and also with cardiolipin (type III). Clones HF-4, HF-7, HB-7 and HL-259 reacted with ssDNA, poly (A), poly (G) and cardiolipin, but not with RNA (type IV). HB-5 and SH-9 antibodies were reactive only with poly (dT) (type V).

HO-323, a human B-lymphoblastoid cell line useful for making human-human hybridomas

A 6-thioguanine-resistant human B-lymphoblastoid cell line, HO-323, was isolated for making human-human hybridomas with high efficiency. Fusions with peripheral blood lymphocytes of systemic lupus erythematosus (SLE) patients and lymphocytes isolated from lymph nodes of lung and breast cancer patients yield constantly more than one hybridoma clones per 10(5) HO-323 cells plated. HO323 cells also fused with lymphocytes from normal peripheral blood to give hybridomas in the same efficiency. The HO-323 cells were diploid with 46 chromosomes and non-secretors of immunoglobulins. This parent cells doubled every 15 hr and could proliferate in serum-containing medium, even if they were plated at low cell density of less than 10(3) cells/ml. The cells could grow in serum-free medium as well as in serum-containing medium, and the resultant human-human hybridomas could also grow in the same media.

Human-human hybridomas secreting antibodies specific to human lung carcinoma

Human Namalwa cells were screened in serum-free medium and in 6-thioguanine, then fused with human lymphocytes from lymph nodes of lung adenocarcinoma cancer patients. Extensive testing using 14 lung cancer cell lines, 11 other cancer cell lines and 4 normal fibroblast lines identified monoclonal antibodies produced by 4 hybridoma clones that reacted specifically with lung adenocarcinoma cells. These monoclonal antibodies also reacted with lung adenocarcinoma tissues and not normal tissues or erythrocytes of any blood type. These hybridoma clones grew and stably secreted the antibodies in serum-free medium as well as in serum-containing medium.

lambda DNA-fragmenting actions of ascorbic acid and triose reductone in the presence of Cu2+

Lambda DNA-fragmenting actions of ascorbic acid (AsA) and triose reductone (TR) in the presence of Cu2+ were studied. The mixture of AsA or TR and Cu2+ caused a marked fragmentation of lambda DNA (3.2 X 10(7) daltons) within the first 1 min of reaction. Further incubation resulted in accumulation of the most abundant species of fragmented lambda DNA having a molecular weight of 1.3 X 10(5) daltons. The mixture of AsA or TR and Cu2+ fragmented calf thymus DNA to produce the fragmented DNA of which 5'-OH terminal groups have a mixture of free OH groups and phosphodiester linkage. The mixture of AsA or TR and Cu2+ was also found to fragment lambda DNA to produce dCMP predominantly as 5'-OH terminal nucleotides.

Formation of mutagens by amino-carbonyl reactions

The formation of mutagens by amino-carbonyl reactions of 20 kinds of amino acid and sugars after heating at 100 degrees C for 10 h was examined by the Ames test. The browned solutions of Gly, Ala, Val, Leu, Ile, Ser, Thr, Gln, Lys X HCl, Arg, Phe, Cys, Met and Pro with Glc caused mutation of Salmonella typhimurium TA100 and/or TA98 with or without S9 mix. The presence of S9 mix increased the mutagenic activity of the browned solutions of Cys and Phe with Glc on TA100 and of those of Gly, Ala, Val, Ile and Cys on TA98, but decreased the activity of other solutions. No revertants of Salmonella were induced by the browned solutions of Trp, Tyr, Asp, Asn, Glu and (Cys)2 with Glc. Among positive browned solutions, Cys, Lys, Arg and Phe had the stronger activity, but their activity was weak compared with that of pyrolysates or chemical mutagens such as Trp-P-1, Trp-P-2 and 4-nitroquinoline-N-oxide. The mutagenic activity of the browned solutions increased with prolongation of heating time and varied with the pH of the reaction mixture. Fru, Gal, Ara, Xyl, Man, Lac and Suc also had the ability to form mutagens in the browning reactions with amino acids.

Function of Cu2+ on the DNA-breaking actions of ascorbic acid and triose reductone

The role of Cu2+ on the DNA-breaking action of ascorbic acid (AsA) and triose reductone (TR) was studied with an agarose slab gel electrophoretic analysis. AsA and TR decomposed calf thymus DNA which had been pretreated with Cu2+, and their decomposing activity was proportional to the concentration of Cu2+ bound to the DNA. The DNA-Cu2+ complex had the ability to oxidize reductones. AsA and TR also decomposed the pretreated DNA with Cu2+ more markedly than that pretreated with Cu2+ and successively with EDTA. The DNA-breaking activity of AsA and TR showed no Cu2+-concentration dependency. The maximal fragmentation of DNA occurred at the concentration ratio of DNA and Cu2+ of 4:1. Excess concentration of Cu2+ decreased the activity of reductones. The present results indicate that the binding of Cu2+ to DNA molecules is also essential for the DNA-breaking action of AsA and TR in the presence of Cu2+ and that Cu2+ bound to DNA molecules has more effective promoting activity than free Cu2+.

Electrophoretic study on the DNA-breaking actions of ascorbic acid and triose reductone in the presence of Cu2+

The mode of DNA-breaking actions of ascorbic acid (AsA) and triose reductone (TR) in the presence of Cu2+ was studied by use of 0.8% agarose slab gel electrophoretic analysis. The DNA-breaking actions of the mixture of AsA or TR and Cu2+ were inhibited by N2 gas, hydroxyl radical scavengers and catalase, indicating that the oxidation of AsA or TR by Cu2+ and the hydrogen peroxide and hydroxyl radicals resulting from the oxidation are essential for the fragmentation of DNA by the mixture of AsA or TR and Cu2+. However, the DNA-breaking activity of these reductones varied with pH, while their oxidation rates were proportional to the increase in pH. The marked fragmentation of DNA occurred at pH 4, 7 or 8. The breakages of DNA by AsA or TR in the presence of Cu2+ were concluded not to be associated with the oxidation rates of reductones.

Breaking action of reductones related to ascorbic acid on nucleic acids

The action of two types of ascorbate-related reductones on nucleic acids was investigated by comparison with that of ascorbic acid (AsA). Amino reductone (ScA) and thiol reductone (MHC) caused strandscissions in nucleic acids. This was confirmed by the fact that reductones lowered the viscosity of DNA solution and shifted the peaks of DNA and RNA to the low molecular side in centrifugal profile. Cu2+ strengthened their action as in the case of enediol reductones. The braking activity of thiol reductone is relatively wesk compared with those of amino and enediol reductones. The preferential degradation of spurinic acid was caused with amino and thiol reductones, suggesting that pyrimidine clusters in nucleic acids were susceptible to breakage.

Effect of reductones on glyoxalase I1

The effect of some reductones on glyoxalase I prepared from animal and microbial origins has been studied. The enzyme was extracted from ox liver or baker's yeast and partially purified by ammonium sulfate fractionation, gel filtration and ion exchange chromatography. Aliphatic reductones such as ascorbic acid, ascorbic acid 3-phosphate and triose reductone showed strong to medium inhibition, while dehydroascorbic acid showed no inhibition. Kinetic analysis indicated that the inhibition mechanism of ascorbic acid was uncompetitive. Varying extents of inhibition were observed among three kinds of diphenols belonging to aromatic reductones. They were in the order of increasing inhibitory power resorcinol, hydroquinone and catechol for the ox liver enzyme, and catechol, resorcinol and hydroquinone for the yeast enzyme. p-Benzoquinone, an oxidized reductone, exhibited marked inhibition on both enzymes. Its action seemed due to reaction with amino and/or sulfhydryl functions of enzyme protein and those of glutathione, one of the substrates.