Capillary electrophoretic separations of peptides using micelle-forming compounds and cyclodextrins as additives

The value of electrokinetic capillary chromatography for separating structurally similar model peptides and tryptic digests is demonstrated. The behavior of model peptides in buffer systems containing dodecyltrimethylammonium bromide, hexadecyltrimethylammonium bromide, sodium dodecyl sulfate and two cyclodextrins as additives is described. These additives, under different analytical circumstances, exhibit certain beneficial effects for peptides with similar net charges but different hydrophobicities. Separations of underivatized peptides, utilizing UV detection, are presented. In addition, separation of fluorescent products of peptides derivatized with o-phthalaldehyde, fluorescamine, and a new reagent, 3-(4-carboxybenzoyl)-2-quinolinecarboxaldehyde, are demonstrated and discussed. Beneficial spectroscopic detection effects with cyclodextrin are also noted.

Modulation of hormone response elements by promoter environment

Hormone response elements (HREs) are nucleotide sequences that confer onto promoters the ability to alter their transcriptional pace in response to hormones. Growing evidence indicates that the functional activity of HREs can be significantly modulated by their promoter environment, making it possible for genes containing the same HRE to display diversity in their responsiveness to a given hormone signal.

Effects of immunoagents on circulating serum hemolysin formation in bone marrow and spleen

The bone marrow as a source of serum hemolysin to sheep red blood cells (SRBC) was studied in splenectomized mice. Splenectomy prevented the hemolysin formation in the primary response, but not in the secondary response. Cyclophosphamide 100 mg/kg and dexamethasone 10 mg/kg decreased hemolysin formation in the bone marrow as well as in the spleen. Levamisole 50 mg/kg increased its formation in both organs. Prednisolone 10 mg/kg significantly suppressed its formation in the spleen, but not in the bone marrow. Hydroxyurea 50 mg/kg suppressed its formation in the bone marrow, but not in the spleen. These results suggest that the bone marrow is the major source of serum hemolysin to SRBC during the secondary response and drug has different effects on antibody production in the bone marrow and in the spleen.

The investigation of antiepileptic action of qingyangshen (QYS)--influences of QYS on the development of rat brain and memory behavior

As an anticonvulsant, the influences of Qingyangshen (QYS) on the development of brain and memory behavior were observed in four-week-old male rats. The dosage of QYS was 100 mg/kg/QOD and the period of administration was one month. The results showed that QYS had less influence on the development of body weight and brain wet weight in young-aged rats than diphenylhydantoin (DPH). However, QYS inhibited the establishment of passive avoidance conditional reflex and had influence on memory behavior in young-aged rats.

A novel enzyme-linked immunosorbent assay (ELISA) for the detection of antibodies to HIV-1 envelope glycoproteins based on immobilization of viral glycoproteins in microtiter wells coated with concanavalin A

We have developed a novel method that greatly simplifies the preparation of solid-phase HIV-1 envelope glycoproteins for use in an ELISA that detects serum antibodies to HIV envelope antigens. This method utilizes concanavalin A absorbed to wells of microtiter plates to affinity immobilize detergent-solubilized viral glycoproteins released in culture fluids of HIV-1 infected cell lines grown in serum free medium. Antibodies binding to ConA-immobilized viral antigens are detected by peroxidase-conjugated antibodies and appropriate enzyme substrates. Unlike most commercial HIV ELISAs, which utilize gp120 depleted-purified virus as the source of antigens and thus favor detection of antibodies to core antigens, the ConA envELISA is highly sensitive for detecting antibodies to native gp120, as evidenced by the strong reactivity of gp120-specific human monoclonal antibodies. Our results also suggest that representation of gp41 in the assay varies and depends on which virus infected cell lines are used for antigen production. Since this assay accurately identified 14 HIV-1 antibody positive patient sera and no false positives were detected among 16 HIV-1 negative sera, the ConA envELISA shows promise as an inexpensive assay for the serologic diagnosis of HIV infections.

Positive- and negative-ion mass spectrometry and rapid clean-up of some carbamate pesticides

Positive-ion electron impact (PIEI), positive-ion chemical ionization (PICI) and negative-ion chemical ionization (NICI) mass spectra of 9 carbamate pesticides are presented. In the PIEI mode, the spectra showed small molecular peaks, intense or base peaks due to M - CH3NHCO + H and peaks at m/z 58 due to CH3NHCO. In the PICI mode, peaks due to M + H, M + C2H5, M - CH3NHCO + 2H, CH3NHCO(m/z 58) and M-28 appeared. The cations at m/z 58 found in both PIEI and PICI modes seem very useful for screening of a carbamate. In the NICI mode, the spectra showed peaks due to M - CH3NHCO and characteristic anions appearing at mass numbers higher than molecular ones, which were probably due to dimerization of [M - CH3NHCO]-followed by hydrogen attachment. Carbamates, which had been added to urine, plasma, whole blood, the liver, kidney and brain, could be rapidly isolated by use of Sep-Pak C18 cartridges with chloroform as an elution solvent. They could be detected by wide-bore capillary gas chromatography with a SPB-5 column, with satisfactory separation from impurities in their underivatized forms.

Transcription and regulation of the cpdB gene in Escherichia coli K12 and Salmonella typhimurium LT2: evidence for modulation of constitutive promoters by cyclic AMP-CRP complex

Measurements of cyclic phosphodiesterase, or of beta-galactosidase in the case of cpdB'-'lacZ fusions, indicate that cpdB expression in both Escherichia coli and Salmonella typhimurium is modulated by carbon source availability, consistent with previous observations in Salmonella. Nucleotide sequence analysis and transcription mapping of both cpdB genes have revealed, in their 5' flanking regions, sequences with good similarity to consensus -10 and -35 regions and cyclic AMP-cyclic AMP receptor protein (cAMP-CRP) binding sites. Furthermore, they are strongly conserved in both organisms. Deletion analysis of an E. coli cpdB'-'lacZ fusion supports the identification of these elements, and a role for the cAMP-CRP binding site in modulating constitutive cyclic phosphodiesterase expression.

Peptidyl-prolyl cis-trans-isomerase from Escherichia coli: a periplasmic homolog of cyclophilin that is not inhibited by cyclosporin A

The prokaryotic peptidyl-prolyl cis-trans-isomerase called "rotamase", a homolog of the human cyclophilin, has been identified in Escherichia coli. The E. coli rotamase, a product of the gene we suggest be called "rot," has been purified to homogeneity after cloning of the gene by the polymerase chain reaction and its overexpression in E. coli. Based on the chymotrypsin-coupled assay using the tetrapeptide substrate succinyl-Ala-Ala-Pro-Phe-p-nitroanilide, the purified protein has rotamase activity identical to human cyclophilin with a catalytic efficiency close to the upper diffusional limit (kcat/Km approximately 1.0 x 10(7) M-1 x S-1 at 10 degrees C). Unlike the human cyclophilins, however, the E. coli rotamase is not significantly inhibited by the immunosuppressant drug cyclosporin A. By spheroplast fractionation of cells harboring the expression vector for the complete rot gene, the rotamase is located in the periplasm, where it could function in refolding of secreted proteins.

[Anti-influenza virus effect of dunhuang air cleaning agent]

Dunhuang air cleaning agent is an emulsion made from the efficacious ingredients of traditional Chinese drugs, antivirotic test in vitro and virus destroying test with atomization were made in our department. It was proved that the agent possesses anti-influenza virus effect. Being an ideal agent for air cleaning, it may be used in the prevention of (common) cold and influenza epidemic.

Identification of conserved and variant epitopes of human immunodeficiency virus type 1 (HIV-1) gp120 by human monoclonal antibodies produced by EBV-transformed cell lines

Using Epstein-Barr virus (EBV) transformation of B cells isolated from peripheral blood of two asymptomatic human immunodeficiency virus type 1-(HIV-1) infected subjects, we have produced four IgG1 human monoclonal antibodies (HMAbs) that bind to HIV-1 gp120, as determined by Western blot analysis. Two of these HMAbs, designated N70-1.5e and N70-2.3a, react with epitopes of gp120 expressed by all strains tested thus far, and therefore, appear to identify conserved epitopes. The other two HMAbs, K24-3b and N70-1.9b, identify variant epitopes; K24-3b binds to an epitope which is absent from two strains but heterogeneously expressed in eight other strains; N70-1.9b binds to an epitope that is found in relatively few strains. We also describe a novel immunoassay in which viral glycoproteins, produced by HIV-1-infected cells grown in serum-free medium, are affinity immobilized in Concanavalin A-coated wells of enzyme-linked immunosorbent assay (ELISA) plates. This method greatly facilitates the preparation of solid-phase HIV envelope glycoproteins from multiple virus strains and screening immunoassays based on this method are highly sensitive and effective in detecting antibodies to gp120.

[Studies of beta-thalassemia mutations and prenatal diagnosis in Guangxi, Guangdong and Sichuan Provinces of south China]

beta-Thalassemia is one of the most common single gene disorders in South China, and ten different point mutations and frameshifts have been observed among Chinese. We studied 150 chromosomes of 95 beta-thalassemia patients from Guangxi, Guangdong and Sichuan Provinces using the polymerase chain reaction followed by dot hybridization with specific oligonucleotide probes. The most common mutations were the frameshift at codon 41-42 and the nonsense mutation at codon 17 in Guangxi and Sichuan, and the codon 41-42 frameshift and IVS-II-654 mutation in Guangdong. The A-G mutation at -28 of the promoter was common in Sichuan but not in the other two provinces. Three mutations, -30, IVS-I-1 and IVS-I-5, were not observed. A prenatal diagnosis program using these techniques has been initiated based on these data. Fourteen pregnancies at risk for beta-thalassemia have been diagnosed successfully.

Histogenesis of hemopoietic bone marrow in adult mice

Based on the concept that the hierarchy of regulatory genes may specify mammalian development, we attempted to evaluate how morphological and functional phenotypes of hemopoietic bone marrow develop in murine models. From studies of local irradiation, s.c. implantation of bone with or without marrow, and renal subcapsular implantation of marrow plugs or bone without marrow, we identified four sequential (necrotic, clearing, stromal proliferating, and hemopoiesis-recovering) responses in the early phase of the reconstruction of hemopoietic marrow that spatially and temporally proceeded in this restricted order. In addition, characteristic hexagonal sinuses were found to participate in the development of hemopoietic marrow in the early phase. The development of hexagonally arranged sinuses seems to coincide with the formation of abundant osseous trabeculae and to precede the appearance of colony-forming units in culture (CFU-C) and spleen colony-forming units (CFU-S). These findings are discussed from the point of the hierarchy of regulation.

Ischemia and reperfusion increase 125I-labeled endothelin-1 binding in rat cardiac membranes

The effect of aerobic perfusion, of up to 90 min global ischemia, and of reperfusion on 125I-labeled porcine endothelin (125I-ET-1) binding site density (Bmax), affinity (KD), and selectivity was investigated using cardiac membranes harvested from adult Sprague-Dawley rats. Membranes from nonperfused hearts bound 125I-ET-1 with a Bmax of 117.0 +/- 8.8 fmol/mg protein, a KD of 0.076 +/- 0.005 nM, and a Hill coefficient approaching unity. Neither aerobic perfusion nor 10 min of normothermic ischemia and subsequent reperfusion altered these binding parameters. The extension of the ischemic episode increased Bmax (23, 32, 62, and 60% increase after 20, 30, 60, and 90 min ischemia, respectively). Reperfusion further increased Bmax (P less than 0.01 at 15 min reperfusion after 20 and 30 min ischemia, and after 30 min reperfusion following 60 min ischemia) without changing selectivity. Affinity was reduced after 60 (P less than 0.05) and 90 (P less than 0.01) min ischemia. Ischemia at 22 degrees C had no effect on the density or affinity of these binding sites.

Cloning, expression, and purification of human cyclophilin in Escherichia coli and assessment of the catalytic role of cysteines by site-directed mutagenesis

The cDNA encoding human cyclophilin from the Jurkat T-cell lymphoma line has been cloned by the expression cassette polymerase chain reaction and sequenced, and an expression vector has been constructed under control of the tac promoter for efficient expression in Escherichia coli. Active cyclophilin is produced at up to 40% of soluble cell protein, facilitating a one-column purification to homogeneity. Wild-type cyclophilin was characterized for binding of the potent immunosuppressant agent cyclosporin A (Kd = 46 nM) by tryptophan fluorescence enhancement and for inhibition (IC50 = 19 nM) of cyclophilin's peptidyl-prolyl cis-trans isomerase (rotamase) activity. With N-succinyl-Ala-Ala-Pro-Phe-p-nitroanilide as the substrate, recombinant human cyclophilin has a high catalytic efficiency; kcat/Km is 1.4 X 10(7) M-1.S-1 at 10 degrees C. To test the prior suggestion that a cysteine residue may be essential for catalysis and immunosuppressant binding, the four cysteines at positions 52, 62, 115, and 161 were mutated individually to alanine and the purified mutant proteins were shown to retain full affinity for cyclosporin A and equivalent catalytic efficiency as a rotamase. Clearly the cysteines play no essential role in catalysis or cyclosporin A binding. These results rule out the recently proposed mechanism [Fischer, G., Wittmann-Liebold, B., Lang, K., Kiefhaber, T. & Schmid, F. X. (1989) Nature (London) 337, 476-478)] involving the formation of tetrahedral hemithioorthoamide. Whereas mechanisms that embody other tetrahedral intermediates may be operative, an alternative mechanism is considered that involves distortion of bound substrate with a twisted (90 degrees) peptidyl-prolyl amide bond.

Synthesis and study of (Z)-3-chlorophosphoenolpyruvate

(Z)-3-Chlorophosphoenolpyruvate has been synthesized by the reaction of 3,3-dichloropyruvic acid with trimethylphosphite, followed by deesterification. This compound is a competitive inhibitor of pyruvate kinase and phosphoenolpyruvate carboxylase. Pyruvate kinase is not inactivated upon prolonged incubation with the compound, but phosphoenolpyruvate carboxylase is slowly inactivated (t1/2 = 5 h). The compound is a substrate for both enzymes, being acted upon by pyruvate kinase approximately 0.1% as rapidly as phosphoenolpyruvate itself. In the case of phosphoenolpyruvate carboxylase, the compound is converted into a 3:1 mixture of chloropyruvate and chlorooxalacetate, at an overall rate that is about 25% the carboxylation rate for phosphoenolpyruvate.

Subcloning of the enterobactin biosynthetic gene entB: expression, purification, characterization, and substrate specificity of isochorismatase

The Escherichia coli entB gene, coding for the enterobactin biosynthetic enzyme isochorismatase, has been subcloned into the multicopy plasmid pKK223-3 under the control of the tac promoter. The resulting recombinant plasmid pFR1 expresses isochorismatase amounting to over 50% of the total cellular protein. The enzyme has been purified to homogeneity and a convenient assay developed. The enzyme has a Km for isochorismate of 14.7 microM and a turnover number of 600 min-1. By use of 1H NMR spectroscopy, the progress of the reaction was followed with the expected formation of 2,3-dihydro-2,3-dihydroxybenzoate product. Several substrate analogues were also utilized by the enzyme including chorismic acid, the immediate precursor to isochorismic acid in the enterobactin biosynthetic pathway.

Overexpression, purification, and characterization of isochorismate synthase (EntC), the first enzyme involved in the biosynthesis of enterobactin from chorismate

Isochorismate synthase (EC 5.4.99.6), the entC gene product of Escherichia coli, catalyzes the conversion of chorismate to isochorismate, the first step in the biosynthesis of the powerful iron-chelating agent enterobactin. A sequence-specific deletion method has been used to construct an EntC overproducer, which allows for the purification and characterization of the E. coli isochorismate synthase for the first time. The N-terminal sequence and the subunit molecular weight (43,000) of the polypeptide derived from SDS-polyacrylamide gel electrophoresis agree with those deduced from DNA sequence data. The enzyme is an active monomer with a native molecular weight of 42,000. It was shown that EntC alone is fully capable of catalyzing the interconversion of chorismate and isochorismate in both directions and the associated activity is not affected by EntA of the same biosynthetic pathway as has recently been speculated [Elkins, M. F., & Earhart, C. F. (1988) FEMS Microbiol. Lett. 56, 35; Liu, J., Duncan, K., & Walsh, C.T. (1989) J. Bacteriol. 171, 791; Ozenberger, B. A., Brickman, T.J., & McIntosh, M. A. (1989) J. Bacteriol. 171, 775]. The kinetic constants were determined with Km = 14 microM and kcat = 173 min-1 for chorismate in the forward direction and Km = 5 microM and kcat = 108 min-1 for isochorismate in the backward direction. The equilibrium constant for the reaction derived from the kinetic data is 0.56 with the equilibrium lying toward the side of chorismate, corresponding to a free energy difference of 0.36 kcal/mol between chorismate and isochorismate.(ABSTRACT TRUNCATED AT 250 WORDS)

[A preliminary study on the pharmacology of the compound prescription huangqin tang and its component drugs]

Results obtained from the pharmacological experiments demonstrated that the compound prescription Huangqin Tang and its component drugs, roots of Paeonia lactiflora, Scutellaria baicalensis and Glycyrrhiza uralensis, and the fruit of Ziziphus jujuba showed marked anti-inflammatory effect. The compound prescription and its component drugs, except the peony root, possessed significant antispastic effect. Antipyretic effect of Radix Scutellariae, Radix Glycyrrhizae and Huangqin Tang was suggested. Huangqin Tang, Radix Paeoniae alba, and Radix Glycyrrhizae showed marked analgesic effect. In addition, the experiments confirmed that both Huangqin Tang and single Radix Scutellariae have sedative effect.

Semistarvation-induced hyperactivity compensates for decreased norepinephrine and dopamine turnover in the mediobasal hypothalamus of the rat

Male Wistar rats were housed in running wheel cages and were restricted in their food intake, in order to reduce the initial body weight by 30% within 10 days. Rats increased their daily running up to distances between 7 and 11 km compared to the maximum 2.5 km in controls fed ad libitum. The hypothalamic noradrenaline (NE) turnover, as estimated by the concentration of the major metabolite MHPG, was significantly decreased in semistarved sedentary rats compared to controls. Hyperactivity resulted in marked elevation of NE turnover at all time points examined. Semistarvation-induced decreases of dopamine (DA) turnover as estimated by the concentrations of its major metabolite DOPAC, could also be compensated by hyperactivity. The circadian pattern of NE turnover parallels the pattern of running activity. MHPG levels at times of high activity were even higher than in controls fed ad libitum (p less than 0.01). The availability of the precursor tyrosine, as indicated by the ratio of plasma tyrosine to the large neutral amino acids, was significantly decreased in semistarvation (p less than 0.0001); hyperactivity caused a further decrease (p less than 0.001), indicating that tyrosine availability is not, under these conditions, a limiting factor for noradrenaline turnover. The combined influence of semistarvation and hyperactivity on central catecholamine turnover in the rat is discussed as an animal model for the effects of malnutrition and heavy exercise often observed in anorexia nervosa.

A clinical evaluation of pulse oximetry during thoracic surgery

To evaluate the utility of pulse oximetry for monitoring oxygenation during thoracic surgery, pulse oximeter oxygen saturation (SpO2) values from the Nellcor N-100 (Nellcor Inc, Haywood, CA) and Novametrix model 500 (Medical Systems Inc, Wallingford, CT) were compared with simultaneous arterial saturation values (SaO2) in 20 patients. A total of 255 matched observations were recorded, and the data were divided for statistical analysis into preinduction of anesthesia and postinduction groups. The preinduction group showed a good correlation between SpO2 and SaO2 values, with both pulse oximeters consistently overestimating the SaO2. However, once anesthesia was induced, there was no longer any correlation for either of the pulse oximeters versus simultaneous SaO2 values, although on average, the SpO2 values were significantly higher than the corresponding SaO2 values. It was concluded that pulse oximetry is useful in following trends of oxygenation in patients with preexisting lung pathology undergoing thoracic surgery, but it cannot replace arterial blood gas sampling for the intraoperative management of respiratory function.

The amino terminus of muscle tropomyosin is a major determinant for function

The amino-terminal region of muscle tropomyosin is highly conserved among muscle and 284-residue non-muscle tropomyosins. Analysis of fusion and nonfusion striated alpha-tropomyosins and a mutant in which residues 1-9 have been deleted has shown that the amino terminus is crucial for function. The presence of 80 amino acids of a nonstructural influenza virus protein (NS1) on the amino terminus of tropomyosin allows magnesium-independent binding of tropomyosin to actin. The fusion tropomyosin inhibits the actomyosin S1 ATPase at all myosin S1 concentrations tested, indicating that the presence of the fusion peptide prevents myosin S1 from switching the actin filament from the inhibited to the potentiated state. Nonfusion tropomyosin, an unacetylated form, has no effect on the actomyosin S1 ATPase, though it regulates normally with troponin. Deletion of residues 1-9, which are believed to overlap with the carboxyl-terminal end of tropomyosin in the thin filament, results in loss of tropomyosin function. The mutant is unable to bind to actin, in the presence and absence of troponin, and it has no regulatory function. The removal of the first 9 residues of tropomyosin is much more deleterious than removal of the last 11 by carboxypeptidase digestion. We suggest that the structure of the amino-terminal region and acetylation of the initial methionine are crucial for tropomyosin function.

Effects of juzen-taiho-toh (TJ-48), a traditional Oriental medicine, on hematopoietic recovery from radiation injury in mice

Effects of Juzen-taiho-toh (TJ-48) on the recovery of hemopoietic systems from radiation injury are analyzed. Female C57BL/6N mice (6-8 weeks old) were irradiated at doses of 1, 2, 3, 5, or 7 Gy from a 60Co source. After irradiation, the mice were given TJ-48 (1.25 g in 100 ml drinking water). Seven days after irradiation, the mice were sacrificed, and bone marrow (both femurs), thymus, spleen, and peripheral blood counts were made. The bone marrow cells were used for fibroblast colony-forming unit (CFU-f), spleen colony-forming unit (CFU-S), granulocyte-macrophage colony-forming unit (CFU-GM), erythroid colony-forming unit (CFU-E), and erythroid burst-forming unit (BFU-E) assays. No difference was observed between the experimental and control groups except for CFU-S counts. In the assay for day-14 CFU-S, the mice injected with TJ-48-treated bone marrow cells showed better general condition (including increased body weight) and heavier spleens with larger and more numerous colonies. The effect of TJ-48 does not seem to be elicited via the hemopoietic microenvironment, because mice that had been given TJ-48 before irradiation at 8 Gy and then injected with syngeneic bone marrow cells did not show enhanced day-14 CFU-S counts. These results suggest that TJ-48 manifests a radioprotective effect by increasing the number and size of day-14 CFU-S.

Antigens similar to major histocompatibility complex B-G are expressed in the intestinal epithelium in the chicken

A monoclonal antibody directed against the erythrocytic B-G antigens of the major histocompatibility complex (MHC) of the chicken, an antiserum raised against purified erythrocytic B-G protein, and a cDNA probe from the B-G subregion were used to look for evidence of the expression of B-G genes in tissues other than blood. Evidence has been found in northern hybridizations, in immunoblots, and in immunolabeled cryosections for the presence of B-G-like antigens in the duodenal and caecal epithelia. Additional B-G-like molecules may be expressed in the liver as well. The B-G-like molecules in these tissues appear larger and somewhat more heterogeneous than the B-G antigens expressed on erythrocytes. Further characterization of these newly recognized B-G-like molecules may help to define a function for the enigmatic B-G antigens of the MHC. al. 1977; Miller et al. 1982, 1984; Salomonsen et al. 1987; Kline et al. 1988), and in the multiplicity of B-G restriction fragment patterns found in genomic DNA from different haplotypes (Goto et al. 1988; Miller et al. 1988; Chaussé et al. 1989). The B-G antigens have contributed, together with the B-F (class I) and B-L (class II) antigens, to the definition of over 27 B system haplotypes in experimental flocks (Briles et al. 1982). Yet the function of the B-G antigens remains entirely unknown. No mammalian counterparts have been identified, although the possibility remains that there may be similar antigens among the blood group systems of mammals. In an effort to define a function of the B-G antigens, a recently cloned B-G sequence (Miller et al. 1988; Goto et al. 1988) and antibodies to the B-G polypeptides (Miller et al. 1982, 1984) were used to examine other tissues for evidence of B-G expression.

Antioxidant action of guilingji in the brain of rats with FeCl3-induced epilepsy

The effects of Guilingji, an antiaging prescription comprised of traditional Chinese medicinal herbs and animal components, on the brain level of thiobarbituric acid reactive substances (TBARS) and superoxide dismutase (SOD) activity in the brain of rats with FeCl3-induced epilepsy were examined with fluorophotometry and electron spin resonance (ESR) spectrometry, respectively. The results showed that pretreatment of rats with Guilingji decreased the levels of TBARS in the left cortex, midbrain, and olfactory lobe, and increased the SOD activity in the midbrain and hypothalamus. These results are the first to demonstrate that Guilingji may possess an antiepileptic effect further to its proposed antiaging action, because decreasing the TBARS elevation and increasing the SOD attenuation in the brain are suggested to be important characteristics of antiepileptic agents. These results suggest that both the proposed antiaging and antiepileptic effects of Guilingji may operate through the mechanism of antioxidation.

Rat primary hepatocyte cultures are a good model for examining metallothionein-induced tolerance to cadmium toxicity

The effect of Zn-induced metallothionein (MT) on the toxicity, uptake, and subcellular distribution of cadmium (Cd) was examined in rat primary hepatocyte cultures and compared to results obtained earlier in this laboratory from intact animals. Hepatocytes were isolated and grown in monolayer culture for 22 h and subsequently treated with ZnCl2 (100 microM) for 24 h, which increased MT concentration about 15-fold. After Zn pretreatment, hepatocytes were exposed to Cd for 24 h. Cytotoxicity was assessed by enzyme leakage, intracellular potassium loss, and cellular glutathione content. The toxicity of Cd was much less in Zn-pretreated cells than in control cells, similar to that previously demonstrated in the intact animal. Zn pretreatment had no appreciable effect on the hepatocellular uptake of 109Cd, but markedly altered its subcellular distribution, with more Cd accumulating in the cytosol and less in the nuclear, mitochondrial, and microsomal fractions. In the cytosol of Zn-pretreated cells, Cd was associated mainly with MT; in contrast, cytosolic Cd in control cells was mainly associated with non-MT macromolecules. Zn-induced changes in the subcellular distribution of Cd in vitro are identical to those observed in vivo in Zn-pretreated rats challenged with Cd. In summary, Zn pretreatment of rat primary hepatocyte cultures protects cells against Cd toxicity. Protection seems to be due to MT-promoted sequestration of Cd and reduction of the amount of Cd associated with critical organelles and proteins. These observations are similar to those noted in the whole animal. These results indicate that cultured hepatocytes are an ideal model for examining MT-induced tolerance to Cd hepatotoxicity.

Characterization of the epidermal growth factor receptor in the gastric mucosa

The effects of epidermal growth factor (EGF), a potent mitogen involved in mucosal protection, are mediated by specific cellular receptors. Here, we present the characteristics and binding properties of EGF receptors in the gastric mucosa. The studies were conducted using cell membranes isolated by subcellular fractionation of rat stomach mucosal scrapings. Specific binding of [125I]-EGF to the membrane preparations was assessed at room temperature for various periods of time and at different pHs. The results showed that the binding was proportional to the incubation time up to 1 h and was not affected by a pH change between 4.0 and 7.0. Scatchard analysis of the binding data infer the presence of 2 binding sites, one of high affinity (Kd = 1.34 nM, Bmax = 34 fmol/mg protein) and the other of low affinity (Kd = 484 nM, Bmax = 2.29 pmol/mg protein). Cross-linking experiments using disuccinimidyl suberate to link the [125I]-EGF to gastric membranes followed by polyacrylamide gel electrophoresis and autoradiography revealed that the major receptor for EGF was a protein of 170 kilodaltons. When the solubilized membranes were subjected to wheat germ agglutinin affinity chromatography, the purified material was found to act as substrate for EGF-stimulated phosphorylation. The major component which was labeled by the [gamma-32P]-ATP was also found to be a 170-kilodalton protein. The data are the first to provide evidence that the gastric mucosa possesses a functional EGF receptor and describe its binding characteristics.

Identification of epidermal growth factor receptor in human buccal mucosa

EGF receptor was identified and its binding characteristics were determined. Buccal mucosa was obtained from 12 healthy volunteers (6 males and 6 females) and assayed individually for [125I]-EGF binding. The specific binding of [125I]-EGF to the receptor ranged from 2.85 to 6.12 fmol/mg protein. There was no significant difference in binding between male and female (4.31 +/- 0.61 versus 3.94 +/- 0.53 fmol/mg protein; mean +/- SEM). Individual tissue homogenates were pooled for Scatchard analysis and cross-linking experiments. Scatchard analysis produced curvilinear plots with a Kd of 0.71 nM and Bmax of 0.024 pmol/mg protein for the high-affinity binding sites, and Kd of 435 nM and Bmax of 9.92 pmol/mg protein for the low-affinity binding sites. To determine the molecular weight of the EGF receptor, the [125I]-EGF and receptor complex were cross-linked by DSS and subjected to SDS-PAGE. The autoradiogram of the gel revealed one major protein band of 160K and a minor band of 170 K, characteristics shared with the EGF receptors in other tissues. The study is thought to be the first to demonstrate the presence of the EGF receptor in human buccal tissue and to show its biochemical features.

[Outcome of the mother and baby delivered by cesarean section in pregnancy induced hypertension. Analysis of 487 cases]

We analyzed the outcome of mother and baby in 487 cases of pregnancy induced hypertension (PIH) delivered by Cesarean section (CS). The indication for CS in 70 cases was simply PIH (14.4%) and 6 out of 9 antepartum eclampsia had CS. There was no maternal or fetal death. The authors suggest that CS should be done whenever eclampsia could not be put under control in order to save both mother and baby. The incidence of postpartum hemorrhage (PPH) was lower in the CS group than in the vaginally delivered group. No late PPH occurred in our CS cases. The incidence of IUGR was 30.4%. Of these IUGR cases 43 were delivered by CS. No stillbirth occurred. The number of neonatal anoxia was less than in the vaginally delivered group (P less than 0.10).

Recombinant granulocyte-macrophage colony-stimulating factor increases adenylate cyclase activity in murine peritoneal macrophages

Granulocyte-macrophage colony stimulating factor (GM-CSF) is a pleiotrophic cytokine which stimulates the function and proliferation of macrophage populations. Although the effects of GM-CSF are diverse and GM-CSF has entered into clinical trials, relatively little is known about signal transduction pathways utilized by GM-CSF. In view of previous studies which have suggested that some of the effects of GM-CSF on monocyte-macrophages can be mimicked by agents which increase intracellular cAMP, we investigated the effect of rGM-CSF on adenylate cyclase (AC) activity in murine peritoneal macrophages. Adenylate cyclase activity was quantitated in macrophage membrane preparations and in intact cells. In seven separate experiments, GM-CSF (50 U/ml) increased AC activity by 61(6)% relative to macrophages treated with carrier medium alone. A dose-dependent increase in AC activity was observed (10 to 100 U/ml) which peaked within 1 to 5 min after the addition of GM-CSF and returned to basal levels by 10 to 20 min. Lineweaver-Burk analysis revealed that the Vmax of macrophage AC was increased from 0.40 to 0.52 pmoles cAMP/min by GM-CSF but the Km was unchanged. Intracellular cAMP was increased by GM-CSF to 129(27)% of control values by 1 min of treatment (n = 6). Under similar experimental conditions, GM-CSF did not increase the activity of PK C (n = 14) or phospholipase A2 (n = 3) in peritoneal macrophages. These data show that macrophage adenylate cyclase activity is rapidly stimulated by GM-CSF. Moreover, these findings support further study of the role of cAMP in transmitting the intracellular signals initiated by GM-CSF in tissue macrophages.