Impacts of Rumen Degradable or Undegradable Protein Supplementation on Supplement Intake and Performance of Yearling Heifers and Cows Grazing Dryland Pastures.

Angus and Red Angus-based yearling heifers (n = 40) and lactating cows (n = 51) were each used in a complete randomized design and stratified by weight and body condition score to one of two treatments: (1) pressed supplement block containing rumen undegradable protein (RUP) and (2) pressed supplement block containing rumen degradable protein (RDP). Heifer and cow supplement intake displayed (p < 0.01) a treatment × period interaction. The RUP heifers and RDP cows consumed more in Period 2 than Period 1, whereas RDP heifers and RUP cows consumed more in Period 1 than Period 2, respectively. Intake rate demonstrated (p < 0.01) a treatment effect for heifers, with RUP consuming supplement faster than the RDP treatment. Intake rate for cows demonstrated (p < 0.01) a treatment × period interaction with RUP cows in Period 1 having faster intakes than Period 2, and RDP cows having the inverse. Cow intake variation displayed (p < 0.01) a treatment × period interaction with RUP cows having more variation in Period 2, while RDP cows had less variation in intake in Period 2. In conclusion, RDP and RUP impacted intake behavior of cows and heifers but had minimal impacts on performance.

Glucose alert system improves health professional responses to adverse glycaemia and reduces the number of hyperglycaemic episodes in non-critical care inpatients.

AIM: To investigate the effect of a novel glucose alert system, comprising the Melbourne Glucose Alert Pathway and glucose-alert-capable networked blood glucose meters, on nursing and hospital medical officer responses to adverse glycaemia. METHODS: A prospective, pre- and post-observational study was undertaken in non-critical care wards of a tertiary hospital over 4 months (n=148 or 660 patient-days). The intervention consisted of two components designed to promote a consistent staff response to blood glucose measurements: (1) a clinical escalation pathway, the Melbourne Glucose Alert Pathway, and (2) networked blood glucose meters, which provide a visual alert for out-of-range blood glucose measurement. All consecutive inpatients with diabetes were assessed for diabetes management and capillary blood glucose. The primary outcome was documented nursing and medical staff action in response to episodes of adverse glycaemia (blood glucose >15 mmol/l or <4 mmol/l). Secondary outcomes consisted of glycaemic measures. RESULTS: In response to episodes of adverse glycaemia, nursing action increased (proportion with nursing action: 45% to 73%; P<0.001), and medical action increased (proportion with medical action: 49% to 67%; P=0.011) with the glucose alert system in place. Patient-days with hyperglycaemia (any blood glucose value >15 mmol/l: 24% vs 16%; P=0.012) and patient-days with mean blood glucose >15 mmol/l (7.4% vs 2.6%; P=0.005) decreased. There was no difference in hypoglycaemia incidence. CONCLUSIONS: Use of a novel glucose alert system improved health professional responses to adverse glycaemia and decreased hyperglycaemia in the hospital setting.

Antagonism of serotonin receptor 1B decreases viability and promotes apoptosis in the COS canine osteosarcoma cell line.

Serotonin receptor 1B (5HTR1B) traditionally exhibits anti-proliferative activity in osteoblasts. We examined the expression and function of 5HTR1B in the COS canine osteosarcoma cell line and normal canine osteoblasts. Equal levels of 5HTR1B gene and protein expression were found between normal and malignant osteoblasts. Treatment with serotonin enhanced viability of osteosarcoma cells but not normal osteoblasts. Challenge with the 5HTR1B agonist anpirtoline caused no change in cell viability. Rather incubation with the specific receptor antagonist SB224289 caused reduction in osteoblast viability, with this effect more substantial in osteosarcoma cells. Investigation of this inhibitory activity showed 5HTR1B antagonism induces apoptosis in malignant cells. Evaluation of phosphorylated levels of CREB and ERK, transcriptional regulators associated with serotonin receptor signalling in osteoblasts, revealed aberrant 5HTR1B signalling in COS. Our results confirm the presence of 5HTR1B in a canine osteosarcoma cell line and highlight this receptor as a possible novel therapeutic target.

Phosphotyrosine enrichment identifies focal adhesion kinase and other tyrosine kinases for targeting in canine hemangiosarcoma.

Canine hemangiosarcoma (HSA) is an endothelial cell malignancy driven, in part, by activating mutations in receptor and non-receptor tyrosine kinases. Proteomics, Western blots and a tyrosine kinase inhibitor were used to elucidate activating mechanisms in HSA cell lines. Phosphotyrosine peptides from focal adhesion kinase (FAK) STAT3, Lyn, Fyn and other signal transduction kinases were identified by mass spectrometry. FAK was constitutively activated at tyrosine 397, the autophosphorylation site, and this was reversible with high concentrations of a FAK inhibitor. FAK inhibitor-14 suppressed migration and phosphorylation of FAK tyrosine 397 and tyrosines 576/577 and was cytotoxic to HSA cells suggesting FAK signalling may be an important contributor to canine HSA survival.

Expression, activity, and subcellular localization of the Yin Yang 1 transcription factor in Xenopus oocytes and embryos.

Yin Yang 1 (YY1) is a multifunctional transcription factor that acts as an activator, repressor, or initiator of transcription of numerous cellular and viral genes. Previous studies in tissue culture model systems suggest YY1 plays a role in development and differentiation in multiple cell types, but the biological role of YY1 in vertebrate oocytes and embryos is not well understood. Here we analyzed expression, activity, and subcellular localization profiles of YY1 during Xenopus laevis development. Abundant levels of YY1 mRNA and protein were detected in early stage oocytes and in all subsequent stages of oocyte and embryonic development through to swimming larval stages. The DNA binding activity of YY1 was detected only in early oocytes (stages I and II) and in embryos after the midblastula transition (MBT), which suggested that its potential to modulate gene expression may be specifically repressed in the intervening period of development. Experiments to determine transcriptional activity showed that addition of YY1 recognition sites upstream of the thymidine kinase promoter had no stimulatory or repressive effect on basal transcription in oocytes and post-MBT embryos. Although the apparent transcriptional inactivity of YY1 in oocytes could be explained by the absence of DNA binding activity at this stage of development, the lack of transcriptional activity in post-MBT embryos was not expected given the ability of YY1 to bind its recognition elements. Subsequent Western blot and immunocytochemical analyses showed that YY1 is localized in the cytoplasm in oocytes and in cells of developing embryos well past the MBT. These findings suggest a novel mode of YY1 regulation during early development in which the potential transcriptional function of the maternally expressed factor is repressed by cytoplasmic localization.

Mechanisms of citral phototoxicity.

Citral, a monoterpene aldehyde synthesized by several plant genera, has been reported to exhibit antimicrobial activity. For the first time, we report that critral exhibits UV-A (315-400 nm) light enhanced oxygen-dependent toxicity against a series of Escherichia coli strains differing in DNA repair and catalase proficiency. Those E. coli strains carrying a gene leading to catalase deficiency (katF) are particularly sensitized to inactivation by citral and UV-A treatment when compared to catalase proficient strains (katF+). Consistent with these in vivo observations, citral when treated with UV-A in vitro produces H2O2. When tested against Fusarium oxysporum and F. solani, fungal root pathogens of Citrus, enhanced toxicity by citral in the presence of UV-A was demonstrated, while dark toxicity was negligible. When the plasmid pBR322 was treated with citral in the presence of UV-A, a change in conformation from the covalently closed circular to the open circular and, ultimately, the linear form was observed. The change in plasmid conformation corresponded to a reduction in transforming activity. Holding plasmid DNA which had been treated with UV-A light in the presence of citral at 4 degrees C for 22 h in the dark resulted in continued degradation of the DNA and loss of transforming activity. Holding plasmid DNA treated with UV-A or citral alone under identical conditions had no detectable effect on either plasmid conformation or transforming activity.

Ferric-ion-photosensitized damage to DNA by hydroxyl and non-hydroxyl radical mechanisms.

Iron(III) and UVA (320-400 nm) light strongly diminished the transforming activity of Haemophilus influenzae DNA in the presence of oxygen. Iron(III) alone in the absence of light had no measurable effect on the transforming activity. The chelating agent ethylenediaminetetraacetic acid (EDTA) conferred virtually complete protection, but hydroxyl radical scavengers (mannitol, methanol, ethanol, isopropanol and dimethyl sulfoxide) inhibited only a small fraction of the inactivation. Treatment of plasmid DNA (pBR322) with iron(III) results in the conversion of the covalently closed circular form of the plasmid to open circles and ultimately to the linear form. Concomitant with the alteration in the conformation of the plasmid, the ability to transform Escherichia coli was reduced. In model systems, iron(III) photoreacted with the DNA backbone causing nicking and double-strand breakage. The results are consistent with a mechanism involving a preliminary complexation of iron(III) by DNA followed by the generation of reactive free radicals other than .OH. We suggest that bound iron, or other UV-absorbing transition metal complexes, may be chromophores capable of causing DNA damage in the long-wave near-UV region.

Sanguinarine, a phototoxic H2O2-producing alkaloid.

Sanguinarine chloride, a quaternary salt of a benzophenanthrene alkaloid, was phototoxic to catalase-deficient strains of Escherichia coli but not to Trichoplusia ni (cabbage looper moth larvae), an insect with high levels of catalase activity. Chemical analyses confirm that sanguinarine is an efficient producer of H2O2. This differential toxicity suggests that the mode of phototoxic action involves production of H2O2 which could be detoxified in many organisms by catalase.