Human α2-HS-glycoprotein/bovine fetuin homologue in mice: identification and developmental regulation of the gene

Human alpha 2-HS-glycoprotein (AHSG) is a plasma protein synthesized in liver and selectively concentrated in bone matrix. It has been reported to be involved in bone formation and resorption as well as immune responses. Recently, AHSG was found to be the species equivalent protein of fetuin, the major fetal serum protein in cattle and sheep. The function and regulation of AHSG/fetuin in different species are not understood. We have isolated a liver cDNA clone that encodes the human AHSG/bovine fetuin homologue in the mouse. The AHSG/fetuin gene may have a role in differentiation since it is expressed in mouse limb buds and brain only at certain stages during development. Mouse liver AHSG/fetuin mRNA was present at low level at 12 days gestation but its level increased during the late part of gestation and peaked between 1 to 3 months after birth. The regulation of mouse AHSG/fetuin synthesis during development was found to be significantly different from that of sheep and bovine fetuin. Compared to fetuin, which is reduced in adult to 1 to 2% of the fetal level, mouse AHSG synthesis subsides only 50% 4 months after birth.

Establishment of hybridoma cell line secreting specific monoclonal antibodies against turnip mosaic virus and analysis of properties of the McAb

Monoclonal antibodies (McAb) of hybridomas derived from the fusing of the mouse splenocytes immunized by TuMV with BALB/c mouse myeloma cells (SP2/0-Ag14). Five kinds of hybridoma cell line were produced by indirect-ELISA screening and cloning three times with limiting dilution. Four kinds of hybridoma produced antibodies respectively reactive to TuMV C1, C3, C4 and C5. One kind was reactive to all five strains of TuMV. In indirect-ELISA and sandwich-ELISA tests, TuMV specific monoclonal antibodies did not react with CaMV, CMV, TMV, PVX, and PVY. Antibody titers of ascitic fluids were about 1:256,000 to 2,048,000 in indirect-ELISA. The biological, physical, and chemical properties of the hybridoma cell lines and McAb were identified. The identification of TuMV strains, the specificity and stability of McAb, the coat proteins, and the antigenic site of TuMV were discussed and analyzed with SDS-PAGE and western-blotting.

Protein-ubiquinone interaction in bovine heart mitochondrial succinate-cytochrome c reductase. Synthesis and biological properties of fluorine substituted ubiquinone derivatives

To investigate the protein-ubiquinone interaction in the bovine heart mitochondrial succinate-cytochrome c reductase region of the respiratory chain, three fluorine substituted ubiquinone derivatives, 2,3-dimethoxy-6-(9'-fluorodecyl)-1,4-benzoquinone (9FQ), 2-methoxy-5-trifluoromethyl-6-decyl-1,4-benzoquinone (TFQ), and 2-methoxy-5-trifluoromethyl-6-(9'-fluorodecyl)-1,4-benzoquinone (9FTFQ), were synthesized. 9FQ was synthesized by radical coupling of Q0 and bis(10-fluoroundecanoyl)peroxide. The latter was prepared by fluorination of undecylenic acid followed by thionylchloride treatment and peroxidation. TFQ was synthesized from 2,2,2-trifluoro-p-cresol by methylation, nitration, reduction, acetylation, nitration, reduction, oxidation, and radical alkylation. 9FTFQ was prepared by the radical alkylation of 2-methoxy-5-trifluoromethyl-1,4-benzoquinone with bis(10-fluoroundecanoyl)peroxide. All three fluoro-Q derivatives are active (greater than 50% the activity of 2,3-dimethoxy-5-methyl-6-decyl-1,4-benzoquinone) when used as electron acceptors for succinate-ubiquinone reductase. However, only 9FQ is active when used as an electron donor for ubiquinol-cytochrome c reductase or as an electron mediator for succinate-cytochrome c reductase. Both TFQ and 9FTFQ are competitive inhibitors for ubiquinol-cytochrome c reductase. A 19FNMR peak-broadening effect was observed for 9FQ when it was reconstituted with ubiquinone-depleted ubiquinol-cytochrome c reductase. A drastic up-field chemical shift was observed for TFQ when it was reconstituted with ubiquinone-depleted reductase. These results indicate that the binding environments of the benzoquinone ring and the alkyl side chain of the Q molecule are different. The strong up-field chemical shift for TFQ, and lack of significant chemical shift for 9FQ, suggest that the benzoquinone ring is bound near the paramagnetic cytochrome b heme.

Case-control study of cigarette smoking and primary hepatoma in an aflatoxin-endemic region of China: a protective effect

Aflatoxin is believed to be a major causative agent in the high incidence of primary liver cancer seen in certain regions of the world. In Fujian Province, an aflatoxin-endemic region of China, we compared the cigarette smoking habits of 200 primary hepatoma patients with those of 200 matched nonhepatoma controls. We excluded from our study all individuals with evidence of hepatitis B virus serum antigen and/or alcoholic cirrhosis. Interestingly, two groups of hepatoma patients could be discerned. In patients more than 50 years of age, a significantly higher number of cases of primary hepatoma was found among nonsmokers than smokers (odds ratio = 2.06; 95% confidence interval = 1.32-3.20). In patients less than 50 years of age, this difference was not seen. Previous studies in the rat, mouse and duck had suggested that agents present in cigarette smoke might induce a cytochrome P450-mediated detoxication pathway, leading to protection against aflatoxin-induced primary liver cancer. Our clinical data in the present study are therefore consistent with the previous laboratory animal experiments.

Extrahepatic expression of plasma protein genes during inflammation

The body's protective responses to infection, wounding, trauma, and malignancy include the acute-phase reaction, which is modulated by various cytokines and their cellular receptors. During the acute-phase reaction, levels of specific proteins synthesized by the liver increase in the plasma. Little information is available about the extrahepatic synthesis of plasma proteins during the acute-phase reaction. The study described here analyzes the tissue-specific expression of genes encoding the plasma proteins albumin (ALB), alpha 1-antitrypsin (AAT), transferrin (TF), haptoglobin (HP), ceruloplasmin (CP), serum amyloid A (SAA), alpha 1-acid glycoprotein (AGP) and alpha 2-HS-glycoprotein (AHSG) during the acute-phase reaction in C57B1 mice. The acute-phase reaction was induced by intraperitoneal injections of bacterial lipopolysaccharide (LPS). During the acute-phase reaction, genes encoding CP, SAA, AGP, and HP demonstrate unique extrahepatic tissue specific patterns of expression in kidney, spleen, thymus, heart, brain, lung, testis, and epididymis. Different temporal patterns of HP gene expression also were observed in lung and thymus after induction by LPS. The function of extrahepatic synthesis of plasma proteins is not yet understood; however, a local provision of specific plasma proteins in mammalian tissues may offer the host a source of functionally important proteins during periods of stress.

[Immunohistochemical observation on keratin filaments of cultured tumor cells by ABC staining]

Avidin-Biotin Peroxidase complex technique, ABV staining, was employed by using monoclonal anti-keratin antibody HK2 in this study. The organization and dynamics of keratins in both interphase and mitotic T56 and HeLa cells were analysed. We also observed the effects of microtubule (MT) and microfilament (MF) inhibitors, colchicine and cytochalasin B, on the organization of keratin filaments in T56 and HeLa cells. The results showed that a significant alteration in the structural organization and distribution of keratin filaments occurred during mitosis, and an extensive rearrangement of keratin networks of the two cell lines was induced in interphase after the MT and MF were disrupted by combined treatment with the two drugs, colchicine and cytochalasin B; the keratin networks turned into a star-like lattice rapidly within 1-2h. Neither colchicine nor cytochalasin B alone elicited significant organizational change in the keratin networks of the two cell lines.

Expression of triplicated and quadruplicated alpha globin genes in sheep

In the sheep alpha alpha alpha globin gene haplotype, the three genes display from the 5' to the 3' end the percentage efficiencies of about 30:14:6, as indicated by the amounts of the three types of alpha chain produced in the alpha alpha alpha/alpha alpha alpha homozygotes. The 3' gene in the alpha alpha alpha alpha haplotype appears to have an efficiency around 1%, as suggested by analysis of one quadruple alpha homozygote. Moreover, the total outputs of the alpha alpha alpha as well as of the alpha alpha alpha alpha haplotypes do not substantially differ from that of the common alpha alpha haplotype.

Compartmentalization and actin binding properties of ABP-50: the elongation factor-1 alpha of Dictyostelium

ABP-50 is the elongation factor-1 alpha (EF-1 alpha) of Dictyostelium discoideum (Yang et al.: Nature 347:494-496, 1990). ABP-50 is also an actin filament binding and bundling protein (Demma et al.: J. Biol. Chem. 265:2286-2291, 1990). In the present study we have investigated the compartmentalization of ABP-50 in both resting and stimulated cells. Immunofluorescence microscopy shows that in addition to being colocalized with F-actin in surface extensions in unstimulated cells, ABP-50 exhibits a diffuse distribution throughout the cytosol. Upon addition of cAMP, a chemoattractant, ABP-50 becomes localized in the filopodia that are extended as a response to stimulation. Quantification of ABP-50 in Triton-insoluble and -soluble fractions of resting cells indicates that 10% of the total ABP-50 is recovered in the Triton cytoskeleton, while the remainder is in the soluble cytosolic fraction. Stimulation with cAMP increases the incorporation of ABP-50 into the Triton cytoskeleton. The peak of incorporation of ABP-50 at 90 sec is concomitant with filopod extension. Immunoprecipitation of the cytosolic ABP-50 from unstimulated cells using affinity-purified polyclonal anti ABP-50 results in the coprecipitation of non-filamentous actin with ABP-50. Purified ABP-50 binds to G-actin with a Kd of approximately 0.09 microM. The interaction between ABP-50 and G-actin is inhibited by GTP but not by GDP, while the bundling of F-actin by ABP-50 is unaffected by guanine nucleotides. We conclude that a significant amount of ABP-50 is bound to either G- or F-actin in vivo and that the interaction between ABP-50 and F-actin in the cytoskeleton is regulated by chemotactic stimulation.

The chromosomes of tufted deer (Elaphodus cephalophus)

Mitotic and meiotic chromosome preparations of the tufted deer (Elaphodus cephalophus) were studied to elucidate the sex-chromosomal polymorphism evidenced by this species. Females had 2n = 46 or 47 chromosomes, whereas males had 2n = 47 or 48 chromosomes. An X;autosome translocation was identified by synaptonemal complex analysis of spermatocytes at pachytene and confirmed by the presence of a trivalent at diakinesis/metaphase I. The present work, in combination with earlier observations by others, indicates that E. cephalophus possesses a varied X-chromosome morphology involving an X;autosome translocation and addition of varying amounts of heterochromatin. It is speculated that sex-chromosome polymorphism may be responsible for the observed differences in diploid chromosome number of tufted deer.

Alpha 2-HS-glycoprotein: expression in chondrocytes and augmentation of alkaline phosphatase and phospholipase A2 activity

The alpha 2-HS-glycoprotein is a plasma protein synthesized in liver and enriched in bone. The concentration of alpha 2-HS-glycoprotein dynamically changes in various physiological conditions and is highest in bone during growth, suggesting that it is involved in regulation of endochondral ossification. Northern blot analysis demonstrated that mRNA transcripts from growth zone and resting zone costochondral chondrocyte cultures hybridized with alpha 2-HS-glycoprotein cDNA. However, a difference of mRNA transcript size was observed, with chondrocyte mRNA transcripts being 2.2 kb, while mRNA isolated from liver was 1.6 kb. Presence of alpha 2-HS-glycoprotein in cartilage cells was found by immunohistochemical staining of human fetal epiphyses using anti-human alpha 2-HS-glycoprotein antibody. To understand the role of alpha 2-HS-glycoprotein in cartilage growth, the effects of exogenous alpha 2-HS-glycoprotein were correlated with alkaline phosphatase (ALPase) and phospholipase A2 (PA2) activity in the chondrocyte cultures. Alkaline phosphatase specific activity was stimulated by alpha 2-HS-glycoprotein at concentrations between 0.25 and 1.25 micrograms/mL in the growth zone and resting zone cultures 2.7 and 2.0-fold, respectively. Matrix vesicle PA2 activity was increased only in the growth zone chondrocyte cultures. These results suggested that alpha 2-HS-glycoprotein may contribute to the regulation of the expression of the chondrocyte phenotype. Steady state mRNA levels of ALPase were analyzed in chondrocytes after additions of alpha 2-HS-glycoprotein. The ALPase mRNA levels remained stationary during the stimulation of enzymatic activity, indicating that the effect of alpha 2-HS-glycoprotein upon alkaline phosphatase activity is not at the transcriptional level.

Effect of nitrendipine on cardiac and renal lesions and arterial hypertrophy. Protective effect of a low dose of calcium antagonist in deoxycorticosterone-induced hypertensive rats

A low dose of nitrendipine (1 mg/kg twice daily) ameliorated the percent incidence and severity of vascular lesions in the kidney and heart induced by deoxycorticosterone (DOC). Less protection was offered by administration of 1 mg/kg of the calcium antagonist once daily. A lower dose of the antagonist (0.5 mg/kg) administered twice daily produced almost no protection against myocardial scars, but the percent incidence and severity of renal tubular casts and glomerular changes were similar to those following injection of 1 mg/kg of the antagonist twice daily. DOC induced hypertrophy of the media in aorta, coronary artery and renal interlobular artery and renal arteriole. Neither 1 mg/kg once or twice daily nor 0.5 mg twice daily of calcium antagonist modified the hypertrophy of the arterial vasculature in the hypertensive DOC group. We conclude that a low dose of the calcium antagonist dissociates at least in part lesions but not hypertrophy from the increased systolic blood pressure, because the antagonist protects against vascular lesions induced by the hypertension. The antagonist likely acts on the endothelial cell of the vessels alone or combined with an effect on the vascular smooth muscle cells.

Identification of an actin-binding protein from Dictyostelium as elongation factor 1a

Indirect evidence has implicated an interaction between the cytoskeleton and the protein synthetic machinery. Two recent reports have linked the elongation factor 1a (EF-1a) which is involved in protein synthesis, with the microtubular cytoskeleton. In situ hybridization has, however, revealed that the messages for certain cytoskeletal proteins are preferentially associated with actin filaments. ABP-50 is an abundant actin filament bundling protein of native relative molecular mass 50,000 (50K) isolated from Dictyostelium discoideum. Immunofluorescence studies show that ABP-50 is present in filopodia and other cortical regions that contain actin filament bundles. In addition, ABP-50 binds to monomeric actin in the cytosol of unstimulated cells and the association of ABP-50 with the actin cytoskeleton is regulated during chemotaxis. Through complementary DNA sequencing and subsequent functional analysis, we have identified ABP-50 as D. discoideum EF-1a. The ability of EF-1a to bind reversibly to the actin cytoskeleton upon stimulation could provide a mechanism for spatially and temporally regulated protein synthesis in eukaryotic cells.

[Inhibiting effect of mitoxantrone on cell cycle progression of Chinese hamster ovary cells]

The effect of Mitoxantrone, a Potential anticancer chemotherapeutic agent, on the cell cycle progression of Chinese Hamster ovary (CHO) cells was investigated by microspectrophotometry. CHO cells incubated with the agent for either 30 min or 24 h were inhibited, to various degrees, from proliferation. The inhibition appeared in dose dependent fashion. A 10-fold dose of the drug was required for the 30 min group, as compared to the 24h group, to develop an equivalent inhibiting effect. When exponentially growing cells were treated with Mitoxantrone for 30 min, washed free of drug, and cultured in fresh medium for another 23.5 h a dose of 0.01 micrograms/ml had little or no effect on the distribution of CHO cells throughout the cell cycle at any point. However, a dose of 0.10-1.00 micrograms/ml was sufficient to cause a decrease of cells in G1 and an accumulation of cells in G2. Block cells had abnormally large nucleus.

Mapping and conservation of the group-specific component gene in mouse

The group-specific component (GC), also known as the vitamin D-binding protein, transports vitamin D and its metabolites in plasma to target tissues throughout the body. The GC gene shares an evolutionary origin with genes encoding albumin (ALB) and alpha-fetoprotein (AFP). All three genes are descendants of an evolutionary ancestor that arose from an intragenic triplication. As a result, each gene is composed of three homologous domains. The study described here characterizes and compares mouse GC to the corresponding nucleotide and amino acid sequences of GC from human and rat. The deduced amino acid sequence of mouse GC was 78% identical to human and 91% identical to rat GC. The results suggest that, unlike the corresponding sequences in the ALB and AFP genes, chromosomal sequences encoding the first domain and the leader sequence of the GC gene have specifically been conserved throughout vertebrate evolution. Protection of domain I during evolution may correlate with an important functional aspect of its sequence. The mouse GC gene was mapped to chromosome 5, where the ALB and AFP genes are also located, demonstrating conservation of the three genes in vertebrate species.

Expression of human plasma protein genes in ageing transgenic mice

Introduction of human plasma protein genes into the mouse genome to produce transgenic mice furnishes an in vivo model for correlating chromosomal DNA sequences with developmental and tissue-specific expression. The liver produces an array of plasma proteins that circulate throughout the body contributing to homeostasis. Non-hepatic tissue sites of synthesis have been identified where a local provision of plasma proteins is needed. Analysis of expression of human plasma protein genes in ageing transgenic mice appears especially promising in identifying DNA sequences that respond to environmental adversities such as inflammatory factors, hormonal changes and metal toxicity. The results indicate that human genes encoding and controlling liver plasma proteins serve as useful models for studying genetic regulation in the background of development and ageing.

Effect of nitrendipine, a calcium antagonist, on the distribution of calcium in aortic smooth muscle cells of deoxycorticosterone-hypertensive rats. A quantitative ultracytochemical study

Rats were made hypertensive by implantation of a pellet of deoxycorticosterone (DOC). A low dose (1 mg/kg twice daily) of the calcium antagonist nitrendipine protects against the increase in total and ionic levels of calcium in the aorta produced by the elevated blood pressure, dissociating at least in part the hypertension from the rise in aortic calcium. Ionic (free) calcium was demonstrated in aortic smooth muscle cells by the pyroantimonate ultra-cytochemical method and the electron opaque reaction product quantitated by stereological techniques. As compared to the control group, nitrendipine did not increase the number of vesicles/micron with precipitate located adjacent to the sarcolemma. DOC however increased the number of subsarcolemmal vesicles with electron opaque precipitate and sarcoplasmic calcium. Nitrendipine administration to DOC-treated rats decreased the number of vesicles to that found in the control or nitrendipine-treated group while ionic calcium in the nitrendipine + DOC group was intermediate between the control or nitrendipine group and the DOC group. The total content of calcium measured by atomic absorption correlates with the observations of ionic calcium levels demonstrated ultracytochemically. Aortic dry weights of the DOC and DOC + nitrendipine groups were comparable and significantly greater than those in the control or nitrendipine groups.

Effects of high-frequency chest wall oscillation on respiratory control in humans

We studied the spontaneous breathing patterns of 10 normal adult volunteers during high-frequency chest wall oscillation (HFCWO), accomplished by inflating and deflating a vest worn around each subject's thorax at 2.5 Hz. Tidal volumes generated by HFCWO averaged 100 ml. Mean vest pressure was maintained at approximately 35 cm H2O throughout each experiment, even when HFCWO was not applied. During HFCWO, subjects were instructed occasionally to exhale deeply to obtain end-tidal samples representative of PACO2. HFCWO increased the breath-to-breath variability of spontaneous respiration in all subjects, prolonging expiratory pauses and producing short apneas in some cases. PACO2 decreased significantly (p less than 0.05). The effects on minute ventilation, tidal volume, and inspiratory and expiratory durations remained variable across subjects, even when differences in PACO2 between control and HFCWO states were reduced through inhalation of a low CO2 mixture. None of the changes were statistically significant, although average expiratory duration increased by 29%. Ventilatory responses to CO2 with and without HFCWO were also measured. Normocapnic (PACO2 = 40 mm Hg) ventilatory drive increased significantly (p less than 0.05) in six subjects (Type 1 response) and decreased substantially in the others (Type 2 response); with hypercapnia, the changes in drive were attenuated in both groups. Consequently, CO2 sensitivity decreased in Type 1 subjects and increased in Type 2 subjects. A simple analysis based on this result shows that with HFCWO, Type 2 subjects breathing air will tend to have a lower spontaneous minute ventilation and become hypercapnic. Type 1 subjects will become hypocapnic, but minute ventilation may be higher or lower than control.(ABSTRACT TRUNCATED AT 250 WORDS)