Examination of chemotactic properties of bovine mammary macrophages

An in vitro model system in which polymorphonuclear leukocytes (PMN) migration under agarose was employed to examine the ability of mammary macrophages to release chemoattractants for PMN. Mammary macrophages were incubated in Hanks' balanced salt solution for up to 12 h in the presence of Staphylococcus aureus. The possibility that the chemotactic activity is mediated through release of interleukin 1 (IL-1) and prostaglandins (PGs) by mammary macrophages was investigated. The data showed that release of chemotactic activity peaked 6 h following addition of S. aureus in the culture medium of mammary macrophages. Very low levels of IL-1 were detected in the same culture medium. Addition of indomethacin, a PGs synthesis inhibitor, was ineffective in altering the chemotactic activity detected in the culture medium of macrophages. These data suggest that it is highly unlikely that the chemotactic activity is mediated through the production of IL-1 and PGs by the mammary macrophages.

Radioimmunoassay for insulin-like growth factor-I in bovine milk

This experiment was designed (1) to study the effectiveness of acid-ethanol extraction and gly-gly HCl incubation to dissociate the IGF-binding protein complex before IGF-I RIA measurements in bovine milk, and (2) to determine the influence of freezing/thawing and defatting of milk samples on IGF-I concentration of milk. Acidification of milk with acid-ethanol (acid-ETOH) liberated more IGF-I from its binding proteins than with gly-gly HCl. Milk samples obtained from three control cows and three rbST-treated cows (41–44 wk postpartum) were treated with acid-ethanol and assayed by a radioimmunoassay. IGF-I concentrations in the milk were 3.30 ± 1.40 for the control cows and 2.77 ± 1.36 ng mL−1 for the rbST-treated cows. Fat removal before or after freezing did not affect milk IGF-I measurements. The milk concentration of IGF-I after freezing/thawing twice was not different from that after freezing/thawing once. The radioimmunoassay resulting from this study should provide a tool for monitoring IGF-I concentrations in milk throughout the entire lactation. Key words: Milk, IGF-I, radioimmunoassay, cows

Plasminogen activator production by bovine milk macrophages and blood monocytes

The type of plasminogen activator (PA) produced by bovine milk macrophages has been determined. Macrophages produce a PA protein with molecular weight of 28,000 and isoelectric point of 8.5, and with enzymatic activity independent of fibrin. These characteristics are identical to those reported for bovine urokinase-PA. Although blood monocytes and milk macrophages produce PA after stimulation with lipopolysaccharide, mammary macrophages are clearly limited in their ability to release PA. At maximal stimulation, 78% of the PA produced by milk macrophages remained cell-associated. In marked contrast, blood monocytes released 76% of the PA produced into the culture medium. Macrophages isolated from mastitic quarters produced higher (2.5 times) amounts of PA, compared with those produced by macrophages isolated from healthy quarters. However, in both cases, macrophages were unable to secrete the protein already produced. The limited PA secretion by milk macrophages might be a residual function of a differentiated macrophage population.

Inhibition of c-mos protein kinase blocks mouse zygotes at the pronuclei stage

The c-mos gene product is required for activation of the maturation-promoting factor (MPF) during oocyte maturation. The c-mos protein also acts as a cytostatic factor which is responsible for meiotic metaphase arrest of vertebrate eggs via stabilization of MPF. Here we show that mouse zygotes contain the c-mos protein. Introduction of a kinase-inhibitory anti-mos antibody into mouse zygotes 12 h after fertilization prevented the first cleavage of zygotes at the pronuclei stage. A second anti-mos antibody, known to allow the mos kinase to function, did not interfere with the formation of two-cell embryos. In addition to its known role in MPF activation in oocyte maturation and meiotic metaphase arrest, our findings indicate that the c-mos protein kinase is also required for completion of pronuclei breakdown following fertilization of mouse eggs.

Effect of bovine skim milk and whey on monocyte function

Previous studies have documented the ability of bovine milk to inhibit lymphocyte proliferation in response to mitogens. It is not known whether inhibition of lymphocyte proliferation is mediated through the action of monocytes. To address this question, we examined the ability of bovine skim milk and whey to affect monocyte function with emphasis on expression of major histocompatibility class II antigens and production of interleukin-1 by monocytes. Data showed that expression of major histocompatibility complex class II molecules and production of interleukin-1 by monocytes were not altered when monocytes were cultured in the presence of bovine skim milk or whey. Thus, it is unlikely that the suppressive effect of milk on lymphocyte proliferation could be mediated through alterations in the expression of major histocompatibility class II molecules or in production of interleukin-1 by monocytes. The role of other monocyte antigens or secretory products, however, should also be evaluated.

Flavin-containing monooxygenase: a major detoxifying enzyme for the pyrrolizidine alkaloid senecionine in guinea pig tissues

Evidence based on optimal pH, thermal stability, and enzyme inhibition data suggests that the NADPH-dependent microsomal N-oxidation of the pyrrolizidine alkaloid senecionine is carried out largely by flavin-containing monooxygenase in guinea pig liver, lung, and kidney. In contrast, the hepatic microsomal conversion of senecionine to the pyrrole metabolite (+/-)-6,7-dihydro-7-hydroxy-1-hydroxymethyl-5H-pyrrolizine (DHP) is catalyzed largely by cytochrome P450. However, the rate of senecionine N-oxide formation (detoxication) far exceeded the rate of DHP formation (activation) in guinea pig liver microsomes over a range of pHs (pH 6.8 to 9.8). In guinea pig lung and kidney microsomes, N-oxide was the major metabolite formed from senecionine with little or no production of DHP. The high rate of detoxication coupled with the low level of activation of senecionine in liver, lung, and kidney may help explain the apparent resistance of the guinea pig to intoxication by senecionine and other pyrrolizidine alkaloids.

Disproportionate alpha- and beta-mRNA sodium pump subunit content in canine vascular smooth muscle

Total RNA isolated from canine saphenous vein smooth muscle cells was examined for Na+ pump alpha- and beta-mRNA content by three increasingly sensitive methods: Northern analysis, RNase protection assay, and polymerase chain reaction. Northern analysis clearly showed the presence of beta-mRNA. An alpha 1 signal was not demonstrable using either Northern analysis with a 1.5-kb cDNA probe or RNase protection. However, an "alpha 1-like" transcript was detected using polymerase chain reaction with two sets of primers constructed to selected areas of the rat alpha 1-cDNA. These data suggest that beta-mRNA in canine blood vessels is in large excess of the alpha 1-mRNA. This discrepancy may be reflected in the relatively low number of Na+ pump sites in this tissue.

The effect of lipopolysaccharide on bovine mammary macrophage function

The effect of Escherichia coli lipopolysaccharide (LPS) on the expression of major histocompatibility complex (MHC) class II molecules by bovine mammary macrophages was examined. The ability of LPS-treated mammary macrophages to support antigen-specific T-cell proliferation, as a measure of their antigen presentation ability, was also evaluated. For this purpose, control and LPS-treated macrophages were pulsed with heat-killed Staphylococcus aureus and then cultured with S. aureus-sensitized T-cells. Our data show that LPS had no significant effect on the expression of MHC class II molecules on the surface of mammary macrophages. Furthermore, LPS-induced macrophages were no more active in supporting T-cell proliferation on a per cell basis than unstimulated macrophages. The lack of macrophage response to LPS with respect to expression of MHC class II molecules and the antigen presentation ability is another example of the hyporesponsive nature of macrophages isolated from the bovine mammary gland.

Secretion of interleukin-1 by bovine milk macrophages

The relative sensitivity of bovine blood monocytes and macrophages isolated from milk to lipopolysaccharide, with respect to interleukin 1 (IL-1) production, was evaluated. Addition of lipopolysaccharide (0 to 30 microgram/ml) to the culture medium resulted in increases in secreted and intracellular IL-1 activity for monocytes and milk macrophages, with maximal stimulation achieved at 30 micrograms of lipopolysaccharide/ml of medium. At this concentration of lipopolysaccharide, monocytes released 76% of the total IL-1, whereas milk macrophages released only 26% of the total IL-1 produced within the cell. Secretion of a small quantity of IL-1 was a common property of macrophages isolated from healthy and mastitic quarters. We concluded that limited secretion of IL-1 may render the milk macrophages less efficient in promoting lymphocyte activation.

Comparison of rainbow trout and mammalian cytochrome P450 enzymes: evidence for structural similarity between trout P450 LMC5 and human P450IIIA4

Studies were undertaken to determine the immunochemical relationship between constitutive trout cytochrome P450s and mammalian cytochrome P450IIIA enzymes. Polyclonal antibodies (IgG) generated against trout P450 LMC5 reacted strongly with P450IIIA1 in dexamethasone-induced rat liver microsomes and with P450IIIA4 in human liver microsomes in immunoblots. In contrast, rabbit anti-P450 LMC1 IgG did not recognize these proteins in rat and human liver microsomes. Reciprocal immunoblots using anti-rat P450IIIA1 showed that this antibody does not recognize trout P450 LMC1 or LMC5. However, anti-human P450IIIA4 IgG was found to cross react strongly with P450 LMC1 and LMC5. Progesterone 6 beta-hydroxylase activity of trout liver microsomes, a reaction catalyzed by P450 LMC5, was markedly inhibited by anti-P450IIIA4 and by gestodene, a mechanism-based inactivator of P450IIIA4. These results provide evidence for a close structural similarity between trout P450 LMC5 and human P450IIIA4.

The role of c-mos proto-oncoprotein in mammalian meiotic maturation

The developmentally regulated expression of c-mos oncogene has led to the speculation that this gene may be involved in gametogenesis and early development. To directly test this possibility, we have used an electric field mediated transfer method to introduce an antibody against the c-mos gene product into living immature mouse oocytes. Control oocytes exposed to the electric field without antibody, non-immune IgG, or c-mos antibody pre-absorbed with the mos peptide underwent normal germinal vesicle breakdown (GVBD) (90%) and formed a polar body by 8 h. Oocytes transferred with antibody against c-mos product underwent GVBD, and chromosome condensation as judged by Hoechst 33258 staining. However, antibody transferred oocytes did not form a polar body. Confocal fluorescence microscopy using antibodies against tubulin demonstrated that 90% of the oocytes that received antibody against c-mos did not assemble a meiotic spindle. In a few instances an abnormal spindle-like structure did form. Electron microscopy confirmed that the nuclear envelope disassembled and revealed many microtubules in a disorganized manner. Western blot analysis showed the presence of p39c-mos in mouse mature oocytes, spermatocytes and granulosa cells. These results suggest a role for c-mos in regulating the assembly and/or function of the spindle during meiotic division in murine.

IGF-I receptors in embryonic skeletal muscle of three strains of chickens selected for differences in growth capacity

IGF-I receptors in embryonic skeletal muscle from three strains of chickens have been characterized. Specific receptors for IGF-I were present in breast and thigh skeletal muscle of 13 d chicken embryos. Dissociation rate constants (Kd) for breast muscle of a slow growing layer strain (Leghorn), an intermediate growth strain (Synthetic Whiterock), and a fast growing broiler strain (Cornish) were 3.24, 3.04, and 2.68 nM, respectively. Kd for the thigh muscle of the slow, intermediate and fast growing strains were 3.30, 2.90 and 3.29 nM, respectively. Kd values were not significantly different between strains or between tissues (p greater than .05). Receptor concentration (Bmax) in breast muscle of slow, intermediate and fast growing strains were 1.22, 1.08 and 0.92 pM/mg protein, respectively. Receptor concentration in thigh muscle of the slow, intermediate and fast growing strains were 0.95, 0.76, and 0.79 pM/mg protein, respectively. Bmax values were significantly different (p less than .05) between breast muscle (1.08 +/- .05 pM/mg protein) and thigh muscle (.84 +/- .05 pM/mg protein). IGF-I receptor number for breast muscle although not statistically significant (p greater than .05), indicated a trend towards differences between the slow growing Leghorn strain and the faster growing Cornish strain. The results suggest that strains of birds with different growth capacity may have different densities of IGF-I receptors in breast skeletal muscle plasma membranes.

[Identification of 10 kinds of Zanthoxylum by pyrolysis GC]

In this paper, pyrolysis GC was applied to differentiate and fingerprint 10 kinds of Zanthoxylum on an OV-101 capillary column. Analytical conditions with this column, operating temperature, pyrolysis time and peak identifications are discussed.

[Adrenomyeloneuropathy in 4 brothers]

Four brothers with adrenomyeloneuropathy are reported. They have developed darkening of the skin the sign of adrenal insufficiency at age of 5-10. During 10 years after that time progressive spastic paraparesis has appeared gradually in all of them and has had aggrevative tendency abruptly in late. Three male cousins of the proband probably died of "juvenile type" of adrenoleucodystrophy.

Requirement of the c-mos protein kinase for murine meiotic maturation

Anti-sense mos oligonucleotides have been shown to block steps required for meiotic maturation of oocytes. In Xenopus oocytes, the block prevents germinal vesicle breakdown (GVBD), an early step in oocyte maturation. In mice the block induced by anti-sense mos occurs at a later step in oocyte maturation concerned with the first polar body emission. Here, we show that mouse oocyte maturation is blocked by introduction of anti-mos antibodies into immature functional oocytes. Antibodies that inhibit the mos kinase blocked GVBD. In contrast, anti-mos antibodies that permit the mos kinase to function do not block GVBD, but interfere with polar body formation. Antibodies pre-reacted with excess cognate peptide had no observable effects on maturation. These results indicate that the c-mos kinase function is required for activation of maturation-promoting factor (MPF) during meiosis. These findings are also consistent with our previous studies which show that the mos kinase directly phosphorylates cyclin B2, a component of MPF (Roy et al., 1990).

[The seroepidemiological observation on hepatitis delta virus infection]

To assess the relationship between hepatitis delta virus (HDV) infection and HBV and reveal the distribution of HDV infection and the feature of epidemic, we collected 271 cases of HBV infected people in Shijiazhuang area and tested anti-HD with EIA from April 1987 to October 1988. This study found the prevalence of HDV infection was as high as 12.92% (35/271), and male prevalence of anti-HD was 14.06% (27/192) and female 10.13% (8/79), but there was no significance difference (P greater than 0.05). This suggested that the area of Shijiazhuan was a spot where HDV infection was high. Among these people, the positive rate of anti-HD in chronic active hepatitis, chronic persistent hepatitis and cirrhosis was much higher than that in HBsAg carriers. These finding indicated that HDV infection (coinfection and superinfection) was important in pathogenesis of chronic hepatitis B and in exacerbating liver disease to cirrhosis. This study confirmed that there was no significant difference between HDV infection and age, sex and occupation among HBV infected people.

[Drug modulation of thromboxane A2/prostacyclin balance and lipid peroxidation in patients with coronary artery disease]

Sixty patients with coronary artery disease (CAD) were investigated in a randomized, placebo-controlled study. Therapeutic dose of diltiazem markedly inhibited the production of whole blood thromboxane A2(TXA2), but had no effect on the production of prostacyclin(PGI2). Both aspirin 20mg/d and diltiazem plus aspirin had marked inhibitive effects on both TXA2 and PGI2. The order of potency of the three regimens in decreasing TXA2/PGI2 ratio was diltiazem plus aspirin greater than diltiazem greater than aspirin. Diltiazem, aspirin and combination of both all decreased significantly serum lipid peroxides level, but had no effect on serum superoxide dismutase concentration. The results indicate that both therapeutic dose of diltiazem and low-dose of aspirin may modulate TXA2/PGI2 balance and inhibit lipid peroxidation in CAD and that the combination of both drugs may result in best therapeutic effect.

Expression and nucleotide sequence analysis of the Legionella pneumophila recA gene

The nucleotide sequence of the L pneumophila recA gene was determined. The coding region was 1044 nucleotides (348 codons), specifying a 37,934 Da protein. Preceding the recA gene was a tandem set of transcription regulatory sequences and putative LexA binding sites. When expressed in E. coli, the cloned recA gene yield two proteins with molecular weights of approximately 38,000 and 35,500 Da. The larger of these two proteins shared 70.4% and 74.6% identity with the E. coli and Pseudomonas aeruginosa RecA proteins, respectively. The 35,500 Da recA encoded protein was presumed to be the product of translation from Met26 which was preceded by an alternate ribosomal binding site.