A portable load cell for in-situ ore impact breakage testing

This paper discusses the design and characterisation of a short, and hence portable impact load cell for in-situ quantification of ore breakage properties under impact loading conditions. Much literature has been published in the past two decades about impact load cells for ore breakage testing. It has been conclusively shown that such machines yield significant quantitative energy-fragmentation information about industrial ores. However, documented load cells are all laboratory systems that are not adapted for in-situ testing due to their dimensions and operating requirements. The authors report on a new portable impact load cell designed specifically for in-situ testing. The load cell is 1.5 m in height and weighs 30 kg. Its physical and operating characteristics are detailed in the paper. This includes physical dimensions, calibration and signal deconvolution. Emphasis is placed on the deconvolution issue, which is significant for such a short load cell. Finally, it is conclusively shown that the short load cell is quantitatively as accurate as its larger laboratory analogues. (C) 2062 Elsevier Science B.V. All rights reserved.

Mutations in exon 3 of the beta-catenin gene are rare in melanoma cell lines

Mutations in exon 3 of the CTNNB1 gene encoding beta-catenin have been reported in colorectal cancer cell lines and tumours. Although one study reported mutations or deletions affecting beta-catenin in 20% of melanoma cell lines, subsequent reports detected a much lower frequency of aberrations in uncultured melanomas. To determine whether this difference in mutation frequency reflected an in vitro culturing artefact, exon 3 of CTNNB1 was screened in a panel of 62 melanoma cell lines. In addition, reverse transcription-polymerase chain reaction (RT-PCR) was performed to detect intragenic deletions affecting exon 3. One out of 62 (1.6%) cell lines was found to carry a mutation, indicating that aberration of the Wnt-l/wingless pathway through activation of beta-catenin is a rare event, even in melanoma cell lines. (C) 2002 Lippincott Williams Wilkins.

Inducible system in human hepatoma cell lines for hepatitis C virus production

We cloned the complete complementary DNA of an isolate of the hepatitis C virus, HCV-S1, into a tetra cycline-inducible expression vector and stably transfected it into two human hepatoma cell lines, Huh7 and HepG2. Twenty-six Huh7 and two HepG2-positive clones were obtained after preliminary screening. Two Huh7 (SH-7 and -9) and one HepG2 (G-19) clones were chosen for further characterisation. Expression of HCV proteins in these cells accumulated from 6 In to 4 days posttreatment. Full-length viral plus-strand RNA was detected by Northern analyses. Using RT-PCR and ribonuclease protection assay, we also detected the synthesis of minus-strand HCV RNA. Plus- and minus-strand viral RNA was still detected after treatment with actinomycin D. Indirect immunofluorescence staining with anti-E2, NS4B, and NS5A revealed that these proteins were mostly localised to the endoplasmic reticulum (ER). Culture media from tet-induced SH-9 cells was separated on sucrose density gradients and analysed for the presence of HCV RNA. Viral RNA levels peaked at two separate ranges, one with a buoyant density of 1.08 g/ml and another from 1.17 to 1.39 g/ml. Electron microscopy demonstrated the presence of subviral-like particles (approximately 20-25 nm in diameter) in the cytoplasm of SH-9 and G-19 cells, which were positively labelled by anti-HCV core antibodies. Anti-E2 antibodies strongly labelled cytoplasmic vesicular structures and some viral-like particles. Complete viral particles of about 50 nm which reacted with anti-E2 antibodies were observed in the culture media of tet-induced SH-9 cells following negative staining. Supernatant from tet-treated SH-9 cells was found to infect naive Huh7 and stable Huh7-human CD81 cells. (C) 2002 Elsevier Science (USA).

Apoptosis and cell proliferation in the development of gastric carcinomas: Associations with c-myc and p53 protein expression

Background and Aim: Patients with gastric carcinomas have a poor prognosis and low survival rates. The aim of the present paper was to characterize cellular and molecular properties to provide insight into aspects of tumor progression in early compared with advanced gastric cancers. Methods: One hundred and nine graded gastric carcinomas (early or advanced stage, undifferentiated or differentiated type) with paired non-cancer tissue were studied to define the correlation between apoptosis (morphology, terminal deoxyribonucleotidyl transferase-mediated dUTP-digoxigenin nick end-labeling), cell proliferation (Ki-67 expression, morphology) and expression and localization of two proteins frequently having altered expression in cancers, namely p53 and c-myc. Results: Overall, apoptosis was lower in early stage, differentiated and undifferentiated gastric carcinomas compared with advanced-stage cancers. Cell proliferation was comparatively high in all stages. There was a high level of p53 positivity in all stages. Only the early- and advanced-stage undifferentiated cancers that were p53 positive had a significantly higher level of apoptosis (P< 0.05). Cell proliferation was significantly greater (P < 0.05) only in the early undifferentiated cancers that had either c-myc or p53-positivity. Conclusions: The results indicate that low apoptosis and high cell proliferation combine to drive gastric cancer development. The molecular controls for high cell proliferation of the early stage undifferentiated gastric cancers involve overexpression of both p53 and c-myc. Overexpression of p53 may also control cancer development in that its expression is associated with higher levels of apoptosis in early and late-stage undifferentiated, cancers. (C) 2002 Blackwell Publishing Asia Pty Ltd.

Unusual ovarian activity in a mare preceding the development of an ovarian granulosa cell tumour

An 8-year-old mare, with a foal at foot, was inseminated on foal heat with frozen semen, with the resultant pregnancy lost between days 34 and 41. The right ovary developed a large anovulatory follicle that was non-responsive to multiple doses of ovulating agents. The follicle eventually appeared to luteinise, although plasma progesterone concentrations did not reflect this. Another follicle developed, responded to GnRH and resulted in a pregnancy from frozen semen that went to term with a healthy foal. When the mare was examined after foaling, the structure on the right ovary appeared to be a granulosa cell tumour; the left ovary was smaller than normal and non-functional. Surgical removal of the right ovary before increasing photoperiod resulted in a return to function of the left ovary and a pregnancy to frozen semen on the second cycle following removal. Figures showing concentrations of inhibin, progesterone, androstenedione, oestradiol and testosterone are presented for this entire period. Unusual ovarian activity in the mare might be a prelude to the development of a granulosa cell tumour.

Phenotypic and genotypic analysis of Helicoverpa armigera nucleopolyhedrovirus serially passaged in cell culture

Rapid accumulation of few polyhedra (FP) mutants was detected during serial passaging of Helicoverpa armigera nucleopolyhedrovirus (HaSNPV) in cell culture. 100% FP infected cells were observed by passage 6. The specific yield decreased from 178 polyhedra per cell at passage 2 to two polyhedra per cell at passage 6. The polyhedra at passage 6 were not biologically active, with a 28-fold reduction in potency compared to passage 3. Electron microscopy studies revealed that very few polyhedra were produced in an FP infected cell (< 10 polyhedra per section) and in most cases these polyhedra contained no virions. A specific failure in the intranuclear nucleocapsid envelopment process in the FP infected cells, leading to the accumulation of naked nucleocapsids, was observed. Genomic restriction endonuclease digestion profiles of budded virus DNA from all passages did not indicate any large DNA insertions or deletions that are often associated with such FP phenotypes for the extensively studied Autographa californica nucleopolyhedrovirus and Gaileria mellonella nucleopolyhedrovirus. Within an HaSNPV 25K FP gene homologue, a single base-pair insertion (an adenine residue) within a region of repetitive sequences (seven adenine residues) was identified in one plaque-purified HaSNPV FP mutant. Furthermore, the sequences obtained from individual clones of the 25KFP gene PCR products of a late passage revealed point mutations or single base-pair insertions occurring throughout the gene. The mechanism of FP mutation in HaSNPV is likely similar to that seen for Lymantria dispar nucleopolyhedrovirus, involving point mutations or small insertions/deletions of the 25K FP gene.

Survival following mechanical ventilation of recipients of bone marrow transplants and peripheral blood stem cell transplants

Survival of bone marrow transplant recipients requiting mechanical ventilation is poor but improving. This study reports a retrospective audit of all haematopoietic stem cell transplant (HSCT) recipients requiring mechanical ventilation at an Australian institution over a period spanning 11 years from 1988 to 1998. Recipients of autologous transplants are significantly less likely to require mechanical ventilation than recipients of allogeneic transplants. Of 50 patients requiring mechanical ventilation, 28% survived to discharge from the intensive care unit, 20% to 30 days post-ventilation, 18% to discharge from hospital and 12% to six months post-ventilation. Risk factors for mortality in the HSCT recipient requiting mechanical ventilation include renal, hepatic and cardiovascular insufficiency and greater severity of illness. Mechanical ventilation of HSCT recipients should not be regarded as futile therapy.

Exercise and T-lymphocyte function: a comparison of proliferation in PBMC and NK cell-depleted PBMC culture

This study utilized recently developed microbead technology to remove natural killer (NK) cells from peripheral blood mononuclear cell (PBMC) preparations to determine the effect of acute exercise on T-lymphocyte function, independent of changes in lymphocyte subpopulations. Twelve well-trained male runners completed a 60-min exercise trial at 95% ventilatory threshold and a no-exercise control trial. Six blood samples were taken at each session: before exercise, midexercise, immediately after exercise, and 30, 60, and 90 min after exercise. Isolated PBMC and NK cell-depleted PBMC were stimulated with the mitogen phytohemagglutinin. Cellular proliferation was assessed by using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide dye uptake. In the PBMC cultures, there was a significantly lower mitogen response to phytohemagglutinin in exercise compared with the control condition immediately postexercise. There were no significant differences between the control and exercise conditions in NK cell-depleted PBMC cultures or in the responses adjusted for the percentage of CD3 cells. The present findings do not support the view that T-lymphocyte function is reduced after exercise.

The relationship of natural killer cell counts, perforin mRNA and CD2 expression to post-exercise natural killer cell activity in humans

The aim of this study was to further investigate the mechanism of suppression of natural killer (NK) cell cytotoxic activity In peripheral blood following strenuous exercise. Blood was collected for analysis of NK cell concentration, cytotoxic activity, CD2 surface expression and perforin gene expression from runners (RUN, n = 6) and resting controls (CONTROL, n = 4) pre-exercise, 0, 1.5, 5, and 24 h following a 60-min treadmill run at 80% of VO2 peak. Natural killer cytotoxic activity, measured using a whole blood chromium release assay, fluctuated minimally in the CONTROL group and increased by 63% and decreased by 43% 0 and 1.5 h post-exercise, respectively, in the RUN group (group x time, P < 0.001). Lytic index (cytotoxic activity per cell) did not change. Perforin mRNA, measured using quantitative real-time polymerase chain reaction (ORT-PCR) decreased from pre- to post-exercise and remained decreased through 24 h, The decrease from pre- to 0 In post-exercise was seen predominately in the RUN group and was inversely correlated r = - 0.95) to pre-exercise perform mRNA. The NK cell surface expression of CD2 (lymphocyte function-associated antigen-2) was determined using fluorescent antibodies and flow cytometry, There was no change in the proportion of NK cells expressing CD2 or CD2 density, We conclude that (1) numerical redistribution accounted for most of the change in NK cytotoxic activity following a strenuous run, (2) decrease in perforin gene expression during the run was inversely related to pre-exercise levels but did not parallel changes in cytotoxic activity, and (3) CD2 surface expression was not affected by exercise.

Peroxisome proliferator-activated receptor beta expression in human breast epithelial cell lines of tumorigenic and non-tumorigenic origin

Peroxisome proliferator-activated receptor beta (PPARbeta) is a member of the nuclear hormone receptor superfamily and is a ligand activated transcription factor. although the precise genes that it regulates and its physiological and pathophysiological role remain unclear. In view of the association of PPARbeta with colon cancer and increased mRNA levels of PPARbeta in colon tumours we sought in this study to examine the expression of PPARbeta in human breast epithelial cells of tumorigenic (MCF-7 and MDA-MB-231) and non-tumorigenic origin (MCF-10A). Using quantitative RT-PCR we measured PPARbeta mRNA levels in MCF-7. MDA-MB-231 and MCF-10A cells at various stages in culture. After serum-deprivation, MDA-MB-231 and MCF-10A cells had a 4.2- and 3.8-fold statistically greater expression of PPARbeta compared with MCF-7 cells. The tumorigenic cell lines also exhibited a significantly greater level of PPARbeta mRNA after serum deprivation compared with subconfluence whereas such an effect was not observed in non-tumorigenic MCF-10A cells. The expression of PPARbeta was inducible upon exposure to the PPARbeta ligand bezafibrate. Our results suggest that unlike colon cancer. PPARbeta overexpression is not an inherent property of breast cancer cell lines. However, the dynamic changes in PPARbeta mRNA expression and the ability of PPARbeta in the MCF-7 cells to respond to ligand indicates that PPARbeta may play a role in mammary gland carcinogenesis through activation of downstream genes via endogenous fatty acid ligands or exogenous agonists. (C) 2002 Elsevier Science Ltd. All rights reserved.