SH3 Domain-Containing Protein 2 Plays a Crucial Role at the Step of Membrane Tubulation during Cell Plate Formation

During cytokinesis in plants, trans-Golgi network-derived vesicles accumulate at the center of dividing cells and undergo various structural changes to give rise to the planar cell plate. However, how this conversion occurs at the molecular level remains elusive. In this study, we report that SH3 Domain-Containing Protein 2 (SH3P2) in Arabidopsis thaliana plays a crucial role in converting vesicles to the planar cell plate. SH3P2 RNAi plants showed cytokinesis-defective phenotypes and produced aggregations of vesicles at the leading edge of the cell plate. SH3P2 localized to the leading edge of the cell plate, particularly the constricted or curved regions of the cell plate. The BAR domain of SH3P2 induced tubulation of vesicles. SH3P2 formed a complex with dynamin-related protein 1A (DRP1A) and affected DRP1A accumulation to the cell plate. Based on these results, we propose that SH3P2 functions together with DRP1A to convert the fused vesicles to tubular structures during cytokinesis.

Technical note: Relationship between infrared thermography and heat production in young bulls

The traditional techniques to measure heat production (HP) are calorimetry (direct and indirect) and comparative slaughter. Both methods are expensive and require extensive amounts of time and infrastructure. Infrared thermography (IRT) could be a faster and less expensive alternative to estimate cattle HP. The objective of this project was to evaluate the use of the IRT technique as an indicator of HP in cattle. A total of 24 bulls (12 Nellore and 12 Black Angus) with initial BW of 380 ± 7 kg were used. Initially, 4 animals of each breed were harvested (baseline animals) and simple regressions were developed for each breed from these baseline animals to estimate the initial chemical composition of the remaining bulls. Eight animals of each breed were fed a silage/concentrate diet for ad libitum intake in individual stalls. On the 25th, 50th, and 75th experimental day, infrared thermal images (Fluke Ti 55ft; Fluke Corporation) were taken of each animal's face to access skin and ocular surface temperatures. A metabolism trial was conducted to estimate the ME intake (MEI). After 84 experimental days, the cattle were harvested and retained energy (RE) and HP were calculated. The data were analyzed using the MIXED and REG procedures of SAS adopting a significance level of 0.05. Angus cattle had a greater daily MEI, HP, and skin and eye temperatures than Nellore. We found significant correlations ( ≤ 0.005) between daily HP and maximum ( = 0.65) and average skin temperatures ( = 0.65) and maximum ( = 0.65) and average ocular surface ( = 0.69) temperatures recorded on d 50. Infrared thermography has potential to be used to evaluate HP in cattle.

Stabilisation of periarticular fractures and osteotomies with a notched head locking T-plate

OBJECTIVE

To report the clinical outcomes and complications of small animals that had articular or periarticular fractures or osteotomies stabilised with a notched head locking T-plate.

METHODS

Medical records were searched retrospectively to identify animals that had a notched head locking T-plate used to stabilise a small articular or periarticular bone fragment.

RESULTS

Nine dogs and two cats had an articular or periarticular bone fragment stabilised with a 2.0- or 2.4-mm notched head locking T-plate (12 procedures). The median body weight was 4.7 kg. The plate was modified by removing holes in 10/12 procedures and a combination of locking and non-locking screws were used in 7/12 procedures. All fractures or osteotomies progressed to clinical union. There were two intraoperative complications (intra-articular screw placement and overlong screw) and two postoperative complications (skin necrosis and stress protection)

CONCLUSIONS

This study reports the successful use of a 2.0- or 2.4-mm notched head locking T-plate for articular or periarticular fractures or osteotomies in a variety of small-breed dogs and cats. Care must be taken to prevent inadvertent penetration of the articular surface, particularly in regions such as the proximal tibia. The ability to modify the plate dimensions intraoperatively proved beneficial in most cases.

Interdomain salt-bridges in the Ebola virus protein VP40 and their role in domain association and plasma membrane localization

The Ebola virus protein VP40 is a transformer protein that possesses an extraordinary ability to accomplish multiple functions by transforming into various oligomeric conformations. The disengagement of the C-terminal domain (CTD) from the N-terminal domain (NTD) is a crucial step in the conformational transformations of VP40 from the dimeric form to the hexameric form or octameric ring structure. Here, we use various molecular dynamics (MD) simulations to investigate the dynamics of the VP40 protein and the roles of interdomain interactions that are important for the domain-domain association and dissociation, and report on experimental results of the behavior of mutant variants of VP40. The MD studies find that various salt-bridge interactions modulate the VP40 domain dynamics by providing conformational specificity through interdomain interactions. The MD simulations reveal a novel salt-bridge between D45-K326 when the CTD participates in a latch-like interaction with the NTD. The D45-K326 salt-bridge interaction is proposed to help domain-domain association, whereas the E76-K291 interaction is important for stabilizing the closed-form structure. The effects of the removal of important VP40 salt-bridges on plasma membrane (PM) localization, VP40 oligomerization, and virus like particle (VLP) budding assays were investigated experimentally by live cell imaging using an EGFP-tagged VP40 system. It is found that the mutations K291E and D45K show enhanced PM localization but D45K significantly reduced VLP formation.

Acute Toxicity in Rats of Chlorinated Hydrocarbons Given via the Intratracheal Route

1 The approximate lethal dose (ALD) of six chlorinated hydrocarbons via the intratracheal route has been determined in rats and compared with published oral LD50 values.

2 The compounds tested in this study were dichloromethane, perchloroethylene, trichloroethylene, carbon tetrachloride, chloroform and ethylene dichloride.

3 A method of administering the materials intratracheally to unanaesthetized animals was developed.

4 The intratracheal ALD of the chlorinated hydrocarbons ranged from 3.1 to 17.5% of the oral LD 50 and death was peracute.

5 Aspiration of chlorinated hydrocarbons may present more of a hazard than oral toxicity and should be considered when rendering first aid or emergency medical treatment.

Patterns and prevalence of medication use across the menstrual cycle among healthy, reproductive aged women

PURPOSE

The purpose of this study is to characterize the patterns of medication intake in healthy, reproductive-age women not using hormonal contraception.

METHODS

Two hundered fifty-nine healthy, premenopausal women (18-44 years of age) enrolled in the BioCycle Study (2005-2007) were followed over two menstrual cycles. Women were excluded if they were currently using oral contraceptives or other chronic medications. Over-the-counter and prescription medication use among participants was evaluated daily throughout the study via a diary assessing type of medication, dosage, units, and frequency. Medications were categorized as allergy, antibiotics, central nervous system (CNS), cold and cough, gastrointestinal, musculoskeletal, and pain medication based on primary active ingredient. Medication use within each category was assessed across standardized 28-day cycles to evaluate differences in use across cycle phases (i.e., early, middle, and late).

RESULTS

Medication use was reported by 73% of participants. The most and least frequently used medications, respectively, were pain (69%) and musculoskeletal medications (1%). Pain, CNS, and antibiotic medication use varied significantly across the cycle, with pain and CNS medication more frequently reported during menses and antibiotics more frequently during the luteal phase. Allergy, cold and cough, gastrointestinal, and musculoskeletal medication use did not vary across the cycle.

CONCLUSIONS

Patterns of medication use among reproductive age women vary across the menstrual cycle for certain types of medications, particularly in pain (e.g., Ibuprofen), antibiotics (e,g, Amoxicillin), and CNS (e.g., Adderall) medications. Future studies involving use of these types of medication in premenopausal women may need to consider the relationship of their use to the menstrual cycle. Copyright © 2016 John Wiley & Sons, Ltd.

Cow-calf reproductive, genetic, and nutritional management to improve the sustainability of whole beef production systems

Optimizing efficiency in the cow-calf sector is an important step toward improving beef sustainability. The objective of the study was to use a model to identify the relative roles of reproductive, genetic, and nutritional management in minimizing beef production systems' environmental impact in an economically viable, socially acceptable manner. An economic and environmental diet optimizer was used to identify ideal nutritional management of beef production systems varying in genetic and reproductive technology use. Eight management scenarios were compared to a least cost baseline: average U.S. production practices (CON), CON with variable nutritional management (NUT), twinning cattle (TWN), early weaning (EW), sire selection by EPD using either on-farm bulls (EPD-B) or AI (EPD-AI), decreasing the calving window (CW), or selecting bulls by EPD and reducing the calving window (EPD-CW). Diets to minimize land use, water use, and/or greenhouse gas (GHG) emissions were optimized under each scenario. Increases in diet cost attributable to reducing environmental impact were constrained to less than stakeholder willingness to pay for improved efficiency and reduced environmental impact. Baseline land use, water use, and GHG emissions were 188 m, 712 L, and 21.9 kg/kg HCW beef. The NUT scenario, which assessed opportunities to improve sustainability by altering nutritional management alone, resulted in a simultaneous 1.5% reduction in land use, water use, and GHG emissions. The CW scenario improved calf uniformity and simultaneously decreased land use, water use, and GHG emissions by 3.2%. Twinning resulted in a 9.2% reduction in the 3 environmental impact metrics. The EW scenario allowed for an 8.5% reduction in the 3 metrics. The EPD-AI scenario resulted in an 11.1% reduction, which was comparable to the 11.3% reduction achieved by EPD-B in the 3 metrics. Improving genetic selection by using AI or by purchasing on-farm bulls based on their superior EPD demonstrated clear opportunity to improve sustainability. When genetic and reproductive technologies were adopted, up to a 12.4% reduction in environmental impact was achievable. Given the modeling assumptions used in this study, optimizing nutritional management while concurrently improving genetic and reproductive efficiency may be promising avenues to improve productivity and sustainability of U.S. beef systems.

Suspected intramedullary bone infarct subsequent to tibial plateau levelling osteotomy in a dog

BACKGROUND

Bone infarction is a syndrome associated with disruption to the medullary blood supply of a long bone and may present as either a cause of lameness or, more commonly, an incidental finding. Bone infarction is a known complication of total hip replacement in the dog and may be associated with several other systemic diseases.

CASE REPORT

A 3-year-old female desexed Labrador Retriever presented for acute lameness 4 weeks following tibial plateau levelling osteotomy (TPLO). Subsequent radiographs revealed an increase in medullary bone opacity, radiographically consistent with a medullary bone infarction. The lesion was followed with serial radiographs and appeared to spontaneously resolve.

CONCLUSION

This is the first reported case of bone infarction following TPLO in the dog. Bone infarction should be considered as an unlikely but potential complication of TPLO.

Invited review: Frontotemporal dementia caused by microtubule-associated protein tau gene (MAPT) mutations: a chameleon for neuropathology and neuroimaging

Hereditary frontotemporal dementia associated with mutations in the microtubule-associated protein tau gene (MAPT) is a protean disorder. Three neuropathologic subtypes can be recognized, based on the presence of inclusions made of tau isoforms with three and four repeats, predominantly three repeats and mostly four repeats. This is relevant for establishing a correlation between structural magnetic resonance imaging and positron emission tomography using tracers specific for aggregated tau. Longitudinal studies will be essential to determine the evolution of anatomical alterations from the asymptomatic stage to the various phases of disease following the onset of symptoms.

Reduction of teat skin mastitis pathogen loads: differences between strains, dips, and contact times

The purpose of these experiments was to (1) assess differences in mastitis pathogen strain sensitivities to teat disinfectants (teat dips), and (2) determine the optimum time for premilking teat dips to remain in contact with teat skin to reduce pathogen loads on teat skin. Two experiments were conducted using the excised teat model. In experiment 1, the differences in mastitis pathogen strain sensitivities to 4 commercially available dips (dip A: 1% H2O2; dip B: 1% chlorine dioxide; dip C: 1% iodophor; and dip D: 0.5% iodophor) were evaluated. Four strains of 11 common mastitis pathogens (Staphylococcus aureus, Streptococcus agalactiae, Mycoplasma bovis, Streptococcus dysgalactiae, Streptococcus uberis, Escherichia coli, Staphylococcus chromogenes, Staphylococcus epidermidis, Staphylococcus hyicus, Staphylococcus xylosus, and Staphylococcus haemolyticus) were tested. In experiment 2, the percentage log reduction of mastitis pathogens (Escherichia coli, Streptococcus uberis, Streptococcus dysgalactiae, Klebsiella species, Staphylococcus chromogenes, Staphylococcus haemolyticus, Staphylococcus xylosus, and Staphylococcus epidermidis) on teat skin with 3 commercially available teat dips: dip A; dip D; and dip E: 0.25% iodophor, using dip contact times of 15, 30, and 45 s, was evaluated. Experiment 1 results indicated significant differences in strain sensitivities to dips within pathogen species: Staphylococcus aureus, Staphylococcus chromogenes, and Streptococcus uberis. Species differences were also found where Mycoplasma bovis (97.9% log reduction) was the most sensitive to tested teat dips and Staphylococcus haemolyticus (71.4% log reduction) the most resistant. Experiment 2 results indicated that contact times of 30 and 45 s were equally effective in reducing recovered bacteria for dips D and E and were also significantly more effective than a 15-s contact time. No differences were seen in recovered bacteria between tested contact times after treatment with dip A. It can be concluded that different mastitis pathogen species and strains within species may possess different sensitivities to teat dips, which may have implications in selection of teat dips on dairies. Furthermore, a 30-s premilking dip contact time for iodophors and 15 s for H2O2 dips may be optimal in reducing pathogen load in the shortest amount of time. A reduction in premilking teat dip contact time may improve milking parlor efficiency.

Relationships between residual feed intake and hepatic mitochondrial function in growing beef cattle

The objective of this study was to evaluate the relationship between hepatic mitochondrial function and residual feed intake (RFI) in growing beef cattle. In Trial 1, RFI was measured in 29 Angus heifers (initial BW = 258.0 ± 24.9 kg) from divergent IGF-I selection lines created at the Eastern Agricultural Research Station (The Ohio State University) fed a grain-based diet (calculated ME = 2.85 Mcal/kg DM). In Trial 2, RFI was measured in 119 Santa Gertrudis steers (initial BW = 308.4 ± 28.1 kg) fed a roughage-based diet (calculated ME = 2.21 Mcal/kg DM). At the end of the RFI measurement period, cattle in Trial 1 (n = 7 low RFI and n = 7 high RFI) and in Trial 2 (n = 6 low RFI and n = 8 high RFI) with measures of RFI exceeding 0.5 (Trial 1) or 1.0 (Trial 2) SD from the mean RFI were selected to measure mitochondrial function. Overall ADG, DMI, and RFI were 1.19 ± 0.15, 9.31 ± 1.12, and 0.00 ± 0.63 kg/d and 0.83 ± 0.16, 9.48 ± 1.00, and 0.00 ± 0.86 kg/d in Trial 1 and 2, respectively. Cattle with low RFI consumed 13 and 24% less (P < 0.05) DM and had 14 and 56% greater (P < 0.05) G:F than cattle with high RFI in Trial 1 and 2, respectively, even though ADG and BW were similar (P > 0.10). In Trial 1, cattle with low RFI tended (P = 0.06) to have greater state 3 respiration rates than cattle with high RFI, but state 3 respiration rates were similar (P > 0.10) between cattle with low and high RFI in Trial 2. In both trials, cattle with low RFI had greater (P < 0.05) acceptor control ratios than their high RFI counterparts. The respiratory control ratio tended (P = 0.09) to be greater for cattle with low RFI compared with high RFI cattle in Trial 1, but no difference (P > 0.10) was observed in Trial 2. Proton-leak kinetics were similar (P > 0.05) between cattle with low and high RFI in both trials. These data suggest that ADP has greater control of oxidative phosphorylation in liver mitochondrial of cattle with low RFI compared to their high RFI counterparts.

Assessment of solid phase microfiber extraction fibers for the monitoring of volatile organoarsinicals emitted from a plant-soil system

Phytoremediation, the use of plants and microbes to clean up inorganic and organic pollutants, has shown great promise as an inexpensive and feasible form of remediation. More recently, studies have shown that some plants have an amazing capacity to volatilize contaminants and can be an effective remediation strategy if the chemicals released are non-toxic. Arsenic contamination and remediation has drawn great attention in the scientific community. However, its toxicity also varies depending on its form. We evaluated, optimized, and then utilized a solid phase microfiber extraction (SPME) head space sampling technique to characterize the organoarsinical emissions from rabbitfoot grass (Polypogon monspeliensis) in arsenic treated soils to determine if the potentially more toxic organic forms of arsenic (AsH3, AsH2CH3, AsH(CH3)2, and As(CH3)3) were being emitted from the plant-soil system. The SPME fiber that proved best fitted for this application was the DVB/CAR/PDMS fiber with a 45 min sampling period. We did detect and confirm the emissions of dimethylchloroarsine (AsCl(CH3)2) and pentamethylarsine (As(CH3)5). However, it was determined that the more toxic organic forms of arsenic were not released during phytovolatilization.

Flagellar waveform dynamics of freely swimming algal cells

We present quantitative measurements of time-dependent flagellar waveforms for freely swimming biflagellated algal cells, for both synchronous and asynchronous beating. We use the waveforms in conjunction with resistive force theory as well as a singularity method to predict a cell's time-dependent velocity for comparison with experiments. While net propulsion is thought to arise from asymmetry between the power and recovery strokes, we show that hydrodynamic interactions between the flagella and cell body on the return stroke make an important contribution to enhance net forward motion.

A retrospective comparison of blood transfusion requirements during cardiopulmonary bypass with two different small adult oxygenators

A low haematocrit during cardiopulmonary bypass (CPB) is associated with adverse outcomes and often results in homologous blood transfusions. Oxygenators with improved venous reservoir designs aid in reducing the priming volume. Recently, we changed our small adult oxygenator model from the D905 EOS oxygenator (Dideco, Mirandola, Italy) to the Capiox FX1540 (Terumo Corporation, Tokyo, Japan). We conducted a retrospective study of 42 patents to evaluate the impact of the Capiox FX 1540 on blood transfusion requirements in small patients (body surface area (BSA) up to 1.8 m(2)). The D905 EOS group had a lower minimum intraoperative haematocrit than the FX1540 group (20 ± 3 v 22 ± 4, p = 0.029) with 73% of the patients receiving intraoperative blood transfusions compared with 30% in the FX 1540 group (p = 0.012). Patients in the D905 EOS group received one blood transfusion more during CPB than the FX 1540 patients (p = 0.002). The haematocrits at the end of CPB and in the early postoperative period were identical in both groups. The postoperative ventilation time, length of stay in the intensive care unit and postoperative chest drain bleeding were similar in both groups. In conclusion, the Capiox FX1540 was effective in reducing intraoperative packed red cell transfusions.

Effects of time on feed and post-mortem aging on palatability and lipid composition of crossbred Wagyu beef

Twenty-seven Wagyu-sired steers were fed for 90 (14 steers) or 170 (13 steers) days to study the effects of time on feed on palatability and fatty acid composition, and the effects of post-mortem aging time (2, 4 or 10 days) on palatability. Hot carcass weight, fat thickness, longissimus dorsi muscle area, yield grade, estimated kidney, pelvic and heart fat and maturity score were increased (p < 0.05) by an additional 80 days on the high concentrate feed, but marbling was not changed (p > 0.05). Feeding the high concentrate diet for 170 days increased Warner-Bratzler shear force values (p < 0.05) and tended to decrease tenderness (p > 0.05), flavor intensity and connective tissue scores. For the 90 day feeding group, 4 days of aging improved connective tissue score (p < 0.05) and tended to increase (p > 0.05) tenderness scores and decrease shear force, compared with 2 days of aging. For the 170 day feeding group, 10 days of aging improved (p < 0.05) shear force and all sensory attributes except flavor intensity, compared to 2 days of aging. An additional 80 days on feed decreased (p < 0.05) stearic acid and total saturated fatty acids (SFA) and generally increased (p < 0.05) monounsaturated fatty acids (MUFA), polyunsaturated fatty acids (PUFA), MUFA:SFA, and PUFA:SFA in subcutaneous fat and longissimus dorsi muscle. The cholesterol content of fat and muscle increased (p < 0.05) as time on feed increased. Ninety days on a high concentrate diet was adequate for yearling crossbred Wagyu steers to produce highly acceptable carcasses. The additional 80 days on feed produced little or no overall benefit and the steers became overfinished and less tender. Ten days post-mortem aging improved (p < 0.05) all palatability attributes except flavor intensity.

Quality of life in haemophilia A: Hemophilia Utilization Group Study Va (HUGS-Va)

This study describes health-related quality of life (HRQoL) of persons with haemophilia A in the United States (US) and determines associations between self-reported joint pain, motion limitation and clinically evaluated joint range of motion (ROM), and between HRQoL and ROM. As part of a 2-year cohort study, we collected baseline HRQoL using the SF-12 (adults) and PedsQL (children), along with self-ratings of joint pain and motion limitation, in persons with factor VIII deficiency recruited from six Haemophilia Treatment Centres (HTCs) in geographically diverse regions of the US. Clinically measured joint ROM measurements were collected from medical charts of a subset of participants. Adults (N = 156, mean age: 33.5 ± 12.6 years) had mean physical and mental component scores of 43.4 ± 10.7 and 50.9 ± 10.1, respectively. Children (N = 164, mean age: 9.7 ± 4.5 years) had mean total PedsQL, physical functioning, and psychosocial health scores of 85.9 ± 13.8, 89.5 ± 15.2, and 84.1 ± 15.3, respectively. Persons with more severe haemophilia and higher self-reported joint pain and motion limitation had poorer scores, particularly in the physical aspects of HRQoL. In adults, significant correlations (P < 0.01) were found between ROM measures and both self-reported measures. Except among those with severe disease, children and adults with haemophilia have HRQoL scores comparable with those of the healthy US population. The physical aspects of HRQoL in both adults and children with haemophilia A in the US decrease with increasing severity of illness. However, scores for mental aspects of HRQoL do not differ between severity groups. These findings are comparable with those from studies in European and Canadian haemophilia populations.

The relationship between ADHD and key cognitive phenotypes is not mediated by shared familial effects with IQ

BACKGROUND

Twin and sibling studies have identified specific cognitive phenotypes that may mediate the association between genes and the clinical symptoms of attention deficit hyperactivity disorder (ADHD). ADHD is also associated with lower IQ scores. We aimed to investigate whether the familial association between measures of cognitive performance and the clinical diagnosis of ADHD is mediated through shared familial influences with IQ.

METHOD

Multivariate familial models were run on data from 1265 individuals aged 6-18 years, comprising 920 participants from ADHD sibling pairs and 345 control participants. Cognitive assessments included a four-choice reaction time (RT) task, a go/no-go task, a choice-delay task and an IQ assessment. The analyses focused on the cognitive variables of mean RT (MRT), RT variability (RTV), commission errors (CE), omission errors (OE) and choice impulsivity (CI).

RESULTS

Significant familial association (rF) was confirmed between cognitive performance and both ADHD (rF=0.41-0.71) and IQ (rF=-0.25 to -0.49). The association between ADHD and cognitive performance was largely independent (80-87%) of any contribution from etiological factors shared with IQ. The exception was for CI, where 49% of the overlap could be accounted for by the familial variance underlying IQ.

CONCLUSIONS

The aetiological factors underlying lower IQ in ADHD seem to be distinct from those between ADHD and RT/error measures. This suggests that lower IQ does not account for the key cognitive impairments observed in ADHD. The results have implications for molecular genetic studies designed to identify genes involved in ADHD.

Comparing total health care costs and treatment patterns of HIV patients in a managed care setting

The objective of this study was to investigate total health care costs and time to occurrence of hospitalization in HIV-infected patients treated according to the 1998 DHHS guidelines in a managed care setting. The study also investigated which patients do not receive guideline treatment. We used a retrospective cross-sectional study design using medical and pharmacy claims data. Data from 1,791 HIV-infected patients using antiretroviral agents between 1 February 1998 and 31 July 1999, including demographic characteristics, medication guideline use, medication adherence and cost of care, were examined. Factors associated with total health care costs and time-to-inpatient admission (as a proxy for patient outcomes) were assessed. Patients receiving guideline (HAART) therapy (55%) had higher prescription and total health care costs but lower medical costs. Patients not receiving treatment according to guidelines were more likely to be female, older, have comorbidities, lower medication adherence and no AIDS-defining illness. Treatment with HAART guidelines was associated with longer time-to-inpatient admission controlling for other factors. In a short-term cross-sectional analysis, patients treated with HAART guidelines had better outcomes based on time-to-inpatient admission but higher prescription and total health care costs. Some patients are at risk for not receiving care according to national treatment guidelines and may be targeted for intervention programmes.

Characterization of susceptibility and carrier status of burbot, Lota lota (L.), to IHNV, IPNV, Flavobacterium psychrophilum, Aeromonas salmonicida and Renibacterium salmoninarum

In this study, susceptibility and potential carrier status of burbot, Lota lota, were assessed for five important fish pathogens. Burbot demonstrated susceptibility and elevated mortality following challenge with infectious haematopoietic necrosis virus (IHNV) by immersion and to Aeromonas salmonicida by intraperitoneal (i.p.) injection. IHNV persisted in fish for at least 28 days, whereas A. salmonicida was not re-isolated beyond 17 days post-challenge. In contrast, burbot appeared refractory to Flavobacterium psychrophilum following intramuscular (i.m.) injection and to infectious pancreatic necrosis virus (IPNV) by immersion. However, i.p injection of IPNV resulted in re-isolation of virus from fish for the duration of the 28 day challenge. Renibacterium salmoninarum appeared to induce an asymptomatic carrier state in burbot following i.p. injection, but overt manifestation of disease was not apparent. Viable bacteria persisted in fish for at least 41 days, and bacterial DNA isolated by diagnostic polymerase chain reaction was detected from burbot kidney tissue 90 days after initial exposure. This study is the first to investigate susceptibility of burbot to selected fish pathogens, and this information will aid in efforts to culture and manage this species.

Nursing outside hospitals: the working experience of community nurses. Educational characteristics and job perceptions

The community nursing practice research project reports the results of a mailed questionnaire survey of nurses employed outside hospitals and nursing homes in Victoria in 1985. Two 10 per cent random samples stratified across practice areas were selected from listings of community nurses providing detailed employment information to the Victorian Nursing Council. An 84 per cent response rate was obtained from these listings yielding 689 responses. This paper reports that part of the study relevant to job entry, job satisfaction, job mobility and perceived career options as well as educational preparation. One half of community nurses entered community nursing after five years of hospital experience. The major reasons for choosing employment in community health nursing were its conditions of work, its autonomy and a dissatisfaction with hospital nursing, rather than a specific orientation to community nursing. These can be appreciated in terms of competing demands by the nurse's family life and her sense of growing professional maturity. Job satisfaction was high, with 87 per cent of nurses in the study population being satisfied or very satisfied. Only one quarter considered opportunities for career advancement to exist in their practice area. In the event only one fifth of nurses regarded promotion as important. The high levels of job satisfaction and the low importance attached to promotion are explicable given the nature of female employment and dissatisfaction with hospital nursing. Despite this high level of job satisfaction, one third of nurses believed they would not be nursing in five years time. Less than one third of nurses felt there was adequate opportunity for advancement in their practice area.(ABSTRACT TRUNCATED AT 250 WORDS)

Inorganic pyrophosphatase induces type I collagen in osteoblasts

INTRODUCTION

The physiologic selectivity of calcification in bone tissue reflects selective co-expression by osteoblasts of fibrillar collagen I and of tissue nonspecific alkaline phosphatase (TNAP), which hydrolyzes the calcification inhibitor pyrophosphate (PP(i)) and generates phosphate (P(i)). Humans and mice deficient in the PP(i)-generating ecto-enzyme NPP1 demonstrate soft tissue calcification, occurring at sites of extracellular matrix expansion. Significantly, the function in osteoblasts of cytosolic inorganic pyrophosphatase (abbreviated iPP(i)ase), which generates P(i) via PP(i) hydrolysis with neutral pH optimum, remains unknown. We assessed iPP(i)ase in Enpp1(-/-) and wild type (WT) mouse osteoblasts and we tested the hypothesis that iPP(i)ase regulates collagen I expression.

METHODS

We treated mouse calvarial osteoblasts with ascorbate and beta-glycerol phosphate to promote calcification, and we assessed cytosolic P(i) and PP(i) levels, sodium-dependent P(i) uptake, Pit-1 P(i) co-transporter expression, and iPP(i)ase and TNAP activity and expression. We also assessed the function of transfected Ppa1 in osteoblasts.

RESULTS

Inorganic pyrophosphatase but not TNAP was elevated in Enpp1(-/-) calvariae in situ. Cultured primary Enpp1(-/-) calvarial osteoblasts demonstrated increased calcification despite flat TNAP activity rather than physiologic TNAP up-regulation seen in WT osteoblasts. Despite decreased cytosolic PP(i) in early culture, Enpp1(-/-) osteoblasts maintained cytosolic P(i) levels comparable to WT osteoblasts, in association with increased iPP(i)ase, enhanced sodium-dependent P(i) uptake and expression of Pit-1, and markedly increased collagen I synthesis. Suppression of collagen synthesis in Enpp1(-/-) osteoblasts using 3,4-dehydroproline markedly suppressed calcification. Last, transfection of Ppa1 in WT osteoblasts increased cytosolic P(i) and decreased cytosolic but not extracellular PP(i), and induced both collagen I synthesis and calcification.

CONCLUSIONS

Increased iPP(i)ase is associated with "P(i) hunger" and increased calcification by NPP1-deficient osteoblasts. Furthermore, iPP(i)ase induces collagen I at the levels of mRNA expression and synthesis and, unlike TNAP, stimulates calcification by osteoblasts without reducing the extracellular concentration of the hydroxyapatite crystal inhibitor PP(i).