Receptor binding and growth-promoting activity of insulin-like growth factor-I in a bovine mammary epithelial cell line (MAC-T3)

Insulin-like growth factor-I (IGF-I) has been known to be mitogenic to a variety of cell types, although a growth-regulatory role for IGF-I on bovine mammary epithelial cells has not been fully investigated. In the present study, we examined the receptor binding of IGF-I and its effect on growth in a bovine mammary epithelial cell line (MAC-T3). Specific receptors for IGF-I were detected on cultured bovine mammary epithelial cells. Competitive binding revealed that half-maximal inhibition of 125I-labelled IGF-I binding by IGF-I was approximately 3 micrograms/l. Dissociation rate constant of the IGF-I receptor was 3.10 +/- 0.06 nmol/l (S.E.M.) with a receptor site concentration of 366 +/- 8 fmol/mg protein for the average of three experiments. IGF-I exerted a positive mitogenic effect on MAC-T3 cells according to both direct DNA assay and thymidine incorporation assay. Moreover, the mitogenic effect of IGF-I on MAC-T3 cells was enhanced by the addition of fetal calf serum in the culture media. The present results suggest that the bovine mammary epithelial cell line (MAC-T3) provides a useful model system with which to study the biological actions of insulin-like growth factors on the bovine mammary secretory tissue in vitro.

[Quality of dihuang (Rehmannia spp.)]

In this paper, the contents of catalpol, water-extract and alcohol-extract materials, ash, total reducing sugar and inorganic elements in Dihuang from different habitats have been measured. The result shows that Huai Dihuang, the genuine drug, excels all those from other habitats in quality. The quality of commercial dry Dihuang may be related closely to the production area, storage time, etc.

Developmental and liver-specific expression directed by the serum amyloid P component promoter in transgenic mice

Transgenic mice were produced by microinjection of a human serum amyloid P component (hSAP) gene or a fusion gene (SS) comprising the promoter for hSAP (nucleotides -600 to -14 from the start codon) and the coding region of the hepatitis B virus surface antigen (HBsAg). In adult mice, both transgenes were expressed only in the liver, and thus the pattern of expression resembled that of the endogenous mouse SAP gene. Both hSAP mRNA and HBsAg were first detected in liver on the second postnatal day. The level of these products increased rapidly and reached the maximum within the first week. These results suggest that the hSAP gene contains a short, cis-acting, developmental, and liver-specific regulatory sequence at the 5' or the 3' end and that this sequence can target expression of the foreign gene.

Metastatic potential of human renal cell carcinoma: experimental model using subrenal capsule implantation in athymic nude mice

The aim of this study was to determine whether subrenal capsule (SRC) implantation is a suitable model for the study of the metastatic potential of our human renal cell carcinoma (HRCC) lines and to establish new sublines with enhanced metastatic ability. NMRI athymic nude mice 7-11 weeks old received SRC implantation of our HRCC lines RC43 and RC21. These lines were not metastatic when implanted s.c. Mice were killed after 4 or 8 weeks, or when moribund. With the RC43 cell line the success rate for implantation was 69%, with 89% of these showing metastases. The average volume of the implanted tumour fragments was 0.5 mm3 (range 0.28-0.7), the average volume at the primary site at the time of death was 9087 (9-32000) mm3. Metastases were found in lymph nodes, liver, spleen, peritoneum, psoas muscle, pancreas, diaphragm and skin. The average volume of the metastases was 4139 (0.5-9000) mm3. Growing cell lines were established in vivo and in vitro from one splenic, one peritoneal, one diaphragmatic, and one hepatic metastasis. These sublines have faster in vivo and slower in vitro growth rates than the parental lines. With the RC21 cell line the success rate for implantation was 56% and the metastatic rate 78%. The average volume of the implanted tumour was 0.8 mm3 (0.28-1.2), the average volume at the primary site at the time of death was 2685 mm3 (1.4-6534) and the average volume of metastases was 7.1 mm3 (0.5-37.5). Metastases were found in lymph nodes, lung and skin. No establishment was attempted for RC21 because of the small dimensions of these metastases.(ABSTRACT TRUNCATED AT 250 WORDS)

[Isolation and identification of a strain of Pseudomonas SP. producing insoluble glucan hydrolase]

A strain, CIB871, isolated from the natural world can hydrolyze insoluble glucan(IG) produced by S. mutans. This organism has been identified to be a strain of Pseudomonas SP. It grows well at 30 degrees C. The optimum medium for producing insoluble glucan hydrolase (IGase) is composed of 0.3% peptone, 0.03% IG and M1 salt solution (NH4)2 SO4 1mg/ml, MgSO4 50 micrograms/ml, FeCl2 50 micrograms/ml, K2HPO4 0.5mg/ml). The IGase production reached maximum when cultured for 65-70 hours.

Age-related changes in glomerular volume and hydroxyproline content in rat and human

Total 4-hydroxyproline content and volume were measured in the same sample of microdissected glomeruli obtained fro rat and human outer or inner cortex. Glomerular volume was determined by computer-assisted image analysis, and 4-hydroxyproline was measured by a highly sensitive gas-liquid chromatographic method. Results were expressed as weight of basement membrane material by comparison with the amount of 4-hydroxyproline in purified basement membrane/mesangial matrix preparations. Microanalyses were possible in samples containing as few as eight human glomeruli. Rat glomerular size increased sevenfold between 5 wk and 2 yr of age, with volume being consistently 36 to 45% greater in inner than in outer cortex glomeruli. Basement membrane material content per glomerulus markedly increased with age (12-fold); however, when expressed per unit volume, this change was greatly reduced (2-fold). Expressed per volume, inner and outer cortex glomerular content of basement membrane material was always similar, regardless of age. Therefore, a greater glomerular size, in itself, does not accelerate the rate of basement membrane material deposition. Glomerular size distributions (measured by skewness and kurtosis) did not change, indicating that, although glomerular volume increases with age, aging does not appear to cause the emergence of distinct glomerular populations within an age group. Basement membrane material accumulation is probably a generalized change. Human glomeruli increased sevenfold in size from infancy to adulthood and then declined during senescence. Contrary to that in the rat, glomerular basement membrane material content appeared to closely follow size changes, thus, varying little from infancy to senescence if expressed per unit of glomerular volume.

The effect of methylation outside the recognition sequence of restriction endonuclease PvuII on its cleavage efficiency

This study is to extend our earlier observation that Dam and Dcm methylation outside the PvuII recognition sequence inhibited PvuII cleavage in one of the three PvuII sites of pGEM4Z-ras DNA. In this paper, a new recombinant plasmid DNA, pGEM4-SV40ori-anti-ras, was constructed which has only two PvuII sites, I and II. The Dam and Dcm-methylated and unmethylated DNAs were produced in Escherichia coli and linearized by ScaI. The DNA molecules were digested with different amounts of PvuII. The results show that by comparing the DNA fragment number and intensity of the partial and final products in agarose gel, PvuII site I on the methylated DNA molecule was digested four- to eight-fold more slowly than site II. In the unmethylated plasmid DNA, the two PvuII sites were cleaved at about the same rate. The difference was caused only by methylation of Dam and Dcm sites outside the PvuII recognition sequence. A methylated Dam site immediately adjacent to the less efficiently cut PvuII site I may be responsible for the inhibitory effect. We suggest that a new parameter, involving methylation of sites outside the recognition sequence, be considered in kinetic experiments on cleavage.

Differential sensitivity of hormone-responsive and unresponsive human prostate cancer cells (LNCaP) to tumor necrosis factor

Two sublines, the hormone-sensitive LNCaP-FGC and the insensitive LNCaP-r (resistant) carcinoma cell lines, originating from the parental human prostatic carcinoma cell line LNCaP were tested for sensitivity to human tumor necrosis factor-alpha (TNF) using the MTT assay. Irrespective of the culture conditions, i.e., whether FGC cell growth was hormone stimulated or hormone deprived, a clear dose-related response was observed between the concentration of TNF (range: 5-5000 U/ml) in the culture medium and the percentage of growth inhibition. In medium containing androgen-depleted serum, in which FGC cells showed reduced proliferative activity, the percentage of inhibition by a concentration of 100 U/ml TNF was substantially higher than that found in hormone-stimulated cells (90% and 60%, respectively). In contrast to the FGC cells, the hormone-insensitive LNCaP-r cells were almost completely resistant to the action of TNF. Growth of the FGC cells was almost completely inhibited, whereas growth of the LNCaP-r cells was retarded with only 20% at dosages up to 5000 U/ml. This substantial difference in TNF responsiveness could not be ascribed to differences in TNF-binding capacity, as both the FGC and LNCaP-r cells were found to contain identical numbers of TNF-receptors (approximately 1000 sites/cell). A possible association between hormone responsiveness and TNF sensitivity is suggested for these LNCaP sublines.

Characterization and genetic mapping of a short, highly repeated, interspersed DNA sequence from rice (Oryza sativa L.)

A short, highly repeated, interspersed DNA sequence from rice was characterized using a combination of techniques and genetically mapped to rice chromosomes by restriction fragment length polymorphism (RFLP) analysis. A consensus sequence (GGC)n, where n varies from 13-16, for the repeated sequence family was deduced from sequence analysis. Southern blot analysis, restriction mapping of repeat element-containing genomic clones, and DNA sequence analysis indicated that the repeated sequence is interspersed in the rice genome, and is heterogeneous and divergent. About 200,000 copies are present in the rice genome. Single copy sequences flanking the repeat element were used as RFLP markers to map individual repeat elements. Eleven such repeat elements were mapped to seven different chromosomes. The strategy for characterization of highly dispersed repeated DNA and its uses in genetic mapping, DNA fingerprinting, and evolutionary studies are discussed.

Effect on production traits of bovine somatotropin for up to three consecutive lactations

Thirteen (control) cows were injected daily with saline and 22 with bST (12 at 10.3 mg/d and 10 at 20.6 mg/d) through wk 5 to 42 of lactation. Nine of the treated cows had received bST in the previous lactation, and 7 cows received bST in the previous two lactations. All control cows and 6 treated cows had not previously received bST. Treatment with bST caused substantial increases in milk production, feed intake, and efficiency of feed conversion in the current lactation, which is consistent with previous trials. Increases in feed intake were established fully within 9 wk of starting bST administration, somewhat earlier than usually reported. Treatment with bST in one or two previous lactations caused a statistically significant 14% reduction in production and 8% reduction in efficiency of feed conversion during the first 9 wk of bST treatment in the current lactation; reductions observed later in lactation were not statistically significant. Differences for other traits were not statistically significant. In combination with earlier trials, these results suggest that, although bST has beneficial effects on production and efficiency traits, these benefits may be considerably lower in the second and subsequent lactations of bST use. However, carry-over effects on cows not receiving bST in the current lactation were not explored in this trial.

Function of bovine mammary macrophages as antigen-presenting cells

The ability of mammary macrophages treated with Staphylococcus aureus to induce antigen-specific T-cell proliferation was compared to that of the autologous blood monocytes. Induction of T-cell proliferation has been correlated with changes in major histocompatibility complex (MHC) class II antigen expression and interleukin 1 (IL-1) production by mammary macrophages and blood monocytes. The present study showed that both monocytes and mammary macrophages treated with S. aureus induced T-cell proliferation. However, there was a 3-fold decrease (P less than 0.05) in T-cell proliferation in macrophage cultures compared to those of blood monocytes, when these cells were treated with S. aureus. Mammary macrophages, the cells less effective in stimulating T-cell proliferation, expressed lower levels (2-fold) of MHC class II molecules and produced less IL-1 (3-fold) than blood monocytes. These data suggest that S. aureus may affect macrophage-T cell interaction by modulating the expression of MHC class II molecules and the synthesis of IL-1 by macrophages.

Specific insulin-like growth factor-I receptors on circulating bovine mononuclear cells

We have examined the presence and properties of specific receptors for IGF-I on bovine mononuclear cells. Competitive binding studies showed that binding of [125I]IGF-I to mononuclear cells was inhibited by unlabelled peptides with the rank of IGF-I greater than IGF-II greater than insulin. The binding of [125I]IGF-I was a function of the cell concentration. Equilibrium dissociation constant and receptor concentration values for the average of 9 adult cows were 1.13 +/- 0.11 nM and 108.9 +/- 24.1 fMol/10(7) cells, respectively. Moreover, IGF-I stimulated thymidine incorporation into bovine mononuclear cells in the absence of serum and phytohemagglutinin (PHA). The existence of specific and functional IGF-I receptors on circulating bovine mononuclear cells would provide an easily accessible source for studying IGF-I receptor changes in the bovine, both in physiologic and pathologic states.

[Electromyographic studies on myotonic dystrophy]

EMG studies were made on 12 cases of myotonic dystrophy (MyD). The EMG of the distal and proximal muscles of the limbs showed no marked difference (P greater than 0.05). The myotonic potentials, pathologic spontaneous potentials and incomplete interference patterns had more marked differences respectively as the durations of the disease were prolonged.

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.