ACUTE EFFECTS OF MOVEMENT VELOCITY ON BLOOD LACTATE AND GROWTH HORMONE RESPONSES AFTER ECCENTRIC BENCH PRESS EXERCISE IN RESISTANCE-TRAINED MEN

This study aimed to compare the effects of different velocities of eccentric muscle actions on acute blood lactate and serum growth hormone (GH) concentrations following free weight bench press exercises performed by resistance-trained men. Sixteen healthy men were divided into two groups: slow eccentric velocity (SEV; n = 8) and fast eccentric velocity (FEV; n = 8). Both groups performed four sets of eight eccentric repetitions at an intensity of 70% of their one repetition maximum eccentric (1RMecc) test, with 2-minute rest intervals between sets. The eccentric velocity was controlled to 3 seconds per range of motion for SEV and 0.5 seconds for the FEV group. There was a significant difference (P < 0.001) in the kinetics of blood lactate removal (at 3, 6, 9, 15, and 20 min) and higher mean values for peak blood lactate (P = 0.001) for the SEV group (9.1 ± 0.5 mM) compared to the FEV group (6.1 ± 0.4 mM). Additionally, serum GH concentrations were significantly higher (P < 0.001) at 15 minutes after bench press exercise in the SEV group (1.7 ± 0.6 ng · mL⁻¹) relative to the FEV group (0.1 ± 0.0 ng · mL⁻¹). In conclusion, the velocity of eccentric muscle action influences acute responses following bench press exercises performed by resistance-trained men using a slow velocity resulting in a greater metabolic stress and hormone response.     

BCL‐XL exerts a protective role against anemia caused by radiation‐induced kidney damage

Studies of gene‐targeted mice identified the roles of the different pro‐survival BCL‐2 proteins during embryogenesis. However, little is known about the role(s) of these proteins in adults in response to cytotoxic stresses, such as treatment with anti‐cancer agents. We investigated the role of BCL‐XL in adult mice using a strategy where prior bone marrow transplantation allowed for loss of BCL‐XL exclusively in non‐hematopoietic tissues to prevent anemia caused by BCL‐XL deficiency in erythroid cells. Unexpectedly, the combination of total body γ‐irradiation (TBI) and genetic loss of Bcl‐x caused secondary anemia resulting from chronic renal failure due to apoptosis of renal tubular epithelium with secondary obstructive nephropathy. These findings identify a critical protective role of BCL‐XL in the adult kidney and inform on the use of BCL‐XL inhibitors in combination with DNA damage‐inducing drugs for cancer therapy. Encouragingly, the combination of DNA damage‐inducing anti‐cancer therapy plus a BCL‐XL inhibitor could be tolerated in mice, at least when applied sequentially.     

Microfilaments and tropomyosin of cultured mammalian cells: isolation and characterization

Microfilaments were isolated from cultured mammalian cells, utilizing procedures similar to those for isolation of "native" thin filaments from muscle. Isolated microfilaments from rat embryo, baby hamster kidney (BHK- 21), and Swiss mouse 3T3 cells appeared structurally similar to muscle thin filaments, exhibiting long, 6 nm Diam profiles with a beaded, helical substructure. An arrowhead pattern was observed after reaction of isolated microfilaments with rabbit skeletal muscle myosin subfragment 1. Under appropriate conditions, isolated microfilaments will aggregate into a form that resembles microfilament bundles seen in situ cultured cells. Isolated microfilaments represent a complex of proteins including actin. Some of these components have been tentatively identified, based on coelectrophoresis with purified proteins, as myosin, tropomyosin, and a high molecular weight actin-binding protein. The tropomyosin components of isolated microfilaments were unexpected; polypeptides comigrated on SDS-polyacrylamide gels with both muscle and nonmuscle types of tropomyosin. In order to identify more specifically these subunits, we isolated and partially characterized tropomyosin from three cell types. BHK-21 cell tropomyosin was similar to other nonmuscle tropomyosins, as judged by several criteria. However, tropomyosin isolated from rate embryo and 3T3 cells contained subunits that comigrated with both skeletal muscle and nonmuscle types of myosin, whereas the BHK cell protein consistently contained a minor muscle-like subunit. The array of tropomyosin subunits present in a cell culture was reflected in the polypeptide chain pattern seen on SDS-polyacrylamide gels of microfilaments isolated from that culture. These studies provide a starting point for correlating changes in the ultrastructural organization of microfilaments with alterations in their protein composition.     

Assessment of Bioaerosols in Swine Barns by Filtration and Impaction

Bioaerosol concentrations inside one naturally ventilated and one mechanically ventilated swine finishing barn were assessed by sampling air using membrane filtration and impaction (six-stage Andersen sampler), and assayed by culture method. The barns, located on the same commercial farm in northeast Kansas, did not show any significant difference (p > 0.05) in concentrations of total and respirable airborne microorganisms. The overall mean total concentrations inside the two barns were 6.6 × 10⁴ colony forming units (CFU)/m³ (SD = 3.8 × 10⁴ CFU/m³) as measured by filtration and 8.6 × 10⁴ CFU/m³ (SD = 5.1 × 10⁴ CFU/m³) by impaction. The overall mean respirable concentrations were 9.0 × 10³ CFU/m³ (SD = 4.1 × 10³ CFU/m³) measured by filtration and 2.8 × 10⁴ CFU/m³ (SD = 2.2 × 10⁴ CFU/m³) by impaction. Total and respirable CFU concentrations measured by impaction were significantly (p < 0.05) higher than that by filtration. The persistent strains of microorganisms were various species of the following genera: Staphylococcus, Pseudomonas, Bacillus, Listeria, Enterococcus, Nocardia, Lactobacillus, and Penicillium. It appears that filtration sampling can be used for a qualitative survey of bioaerosols in swine barns while the Andersen sampler is suitable for both quantitative and qualitative assessments. Received: 2 April 2001 / Accepted: 13 June 2001     

Recommendations for Reporting and Flagging of Reference Limits on Pathology Reports

Surveys by the RCPA PITUS Project have shown significant variations in report rendering between Australasian Pathology Providers. The same project collected anecdotal evidence that this variation has led to the misunderstanding and misreading of results - a clinical safety issue. Recommendations are given for the rendering of reference limits on pathology reports, determination and rendering of result flags, and the documentation of sub-population partitions for reference intervals. These recommendations apply equally for paper or electronic reporting, but should not limit the use of novel techniques within electronic reports to convey additional meaning. PITUS Working Group 4 will publish draft recommendations for peer review and comment in relation to the above in the second half of 2014.