Delphi Plus: A novel methodology for identifying evidence-based data standards for health service decision-making

The underlying tenet of evidence-based decision-making in health services is assessing all the relevant evidence. Using the traditional qualitative and quantitative approaches to identifying evidence may not capture the full spectrum of factors that need to be addressed. A selective mixed-method approach may provide a comprehensive assessment of the relevant knowledge. This paper adds to the methodological literature by outlining a novel sequential, mixed-method, exploratory process for identifying evidence-based data standards that may be used for health service decision-making. The three-phase process, entitled Delphi Plus, engages peer-nominated topic-specific experts to assess all publicly available and practice-based items and, through a series of reviews, reach an evidence-based consensus on standards for decision-making. Each process phase is outlined in-depth and supplemented by practical learnings gained through its implementation. The Delphi Plus methodology provides the first comprehensive process for combining the published and practised data to develop evidence-based data standards. The routine use of Delphi Plus would provide a framework for benchmarking in health services, enabling greater monitoring and evaluation of client outcomes and improving quality care. This manuscript describes the process of implementing Delphi Plus and provides an example of data standards generated from its use, which directly inform the Australian Government's Primary Health Care 10 Year Plan.

Implementing evidence-based clinical and business data standards in Australian private practice clinics is feasible

AIMS

To assess the feasibility of implementing data standards in Australian primary care dietetics practices.

METHODS

A mixed-methods pragmatic study of dietitians working in primary care. Using a four-point Likert scale, participants were surveyed on their baseline use of the 45 business and 33 clinical evidenced-based data standards. The content validity index and kappa statistic for each standard were calculated with a kappa statistic of 0.60-0.74 considered 'Good' and > 0.74 'Excellent'. After 4 weeks of assessment, dietitians were surveyed on the feasibility of implementing each standard and standards in total. Qualitative feedback on enablers and barriers to implementing standards was gathered and triangulated with interviews with select participants.

RESULTS

Forty-five dietitians from every Australian state and territory completed both surveys (response rate: 100%). At baseline, 24% of business and 79% of clinical standards were rated 'Good' or 'Excellent' for current usage. The feasibility of implementing standards was rated 'Good' or 'Excellent for 86% of the business and 97% of the clinical standards. Software, training and time limitations are enablers and barriers to implementing standards.

CONCLUSION

Embedding data standards within dietetics practices are feasible and have broad applicability for assessing outcomes of care.

Minimum reporting standards for process and outcomes assessments for private practice dietitians working in Australian primary care: The Thought Leader Consensus study

AIM

To identify minimum reporting standards for assessing the processes and outcomes of Australian primary care dietetics practice.

METHODS

A sequential, mixed-method, exploratory process with peer-nominated Australian 'thought leaders'. A literature review was undertaken to identify possible standards, followed by semi-structured qualitative interviews with thought leaders. Content analysis was used to identify a comprehensive group of items that could inform evidence-based reporting standards. Two rounds of a modified Delphi survey were conducted with the same thought leaders to seek consensus on the most relevant items. Individual items were analysed for content validity, and those with a rating of excellent item-content validity (index >0.78) were included as evidenced-based standards for primary care practice.

RESULTS

Twenty-six thought leaders (response rate: 87%) from all mainland Australian states completed a qualitative interview and two rounds of modified-Delphi consensus surveys. Items were identified and categorised into three domains: business, clinical, and implementation. Content analysis identified 216 items published or used in practice by the thought leaders. After two rounds of consensus review, 97 items (45 business, 33 clinical, and 19 implementation) achieved excellent consensus ratings. Combining these items into a standardised tool, the scale-content validity index average was >0.90, which is considered excellent content validity.

CONCLUSIONS

This study has identified minimum reporting standards for evidence-based process and outcome assessments in primary care dietetics practice in Australia. Incorporating such standards into a standardised tool could enable benchmarking across the dietetics workforce and contribute to a broader understanding of the dietetic impact on public health.

Seedbed not rescue effect buffer the role of extreme precipitation on temperate forest regeneration

Alterations in global climate via extreme precipitation will have broadscale implications on ecosystem functioning. The increased frequency of drought, coupled with heavy, episodic rainfall are likely to generate impacts on biotic and abiotic processes across aquatic and terrestrial ecosystems. Despite the demonstrated shifts in global precipitation, less is known how extreme precipitation interacts with biophysical factors to control future demographic processes, especially those sensitive to climate extremes such as organismal recruitment and survival. We utilized a field-based precipitation manipulation experiment in 0.1 ha forest canopy openings to test future climate scenarios characterized by extreme precipitation on temperate tree seedling survival. The effects of planting seedbeds (undisturbed leaf litter/organic material vs. scarified, exposed mineral soils), seedling ontogeny, species, and functional traits were examined against four statistically defined precipitation scenarios. Results indicated that seedlings grown within precipitation treatments characterized by heavy, episodic rainfall preceded by prolonged drying responded similarly to drought treatments lacking episodic inputs. Moreover, among all treatment conditions tested, scarified seedbeds most strongly affected seedling survivorship (odds ratio 6.9). Compared with any precipitation treatment, the effect size (predicted probabilities) of the seedbed was more than twice as important in controlling seedling survivorship. However, the interaction between precipitation and seedbed resulted in a 27.9% improvement in survivorship for moisture-sensitive species. Seedling sensitivity to moisture was variable among species, and most closely linked with functional traits such as seed mass. For instance, under dry moisture regimes, survivorship increased linearly with seed mass (log transformed; adjusted R²  = 0.72, p < 0.001), yet no relationship was apparent under wet moisture regimes. Although precipitation influenced survival, extreme rainfall events were not enough to offset moisture deficits nor provide a rescue effect under drought conditions. The relationships reported here highlight the importance of plant seedbeds and species (e.g., functional traits) as edaphic and biotic controls that modify the influence of extreme future precipitation on seedling survival in temperate forests. Finally, we demonstrated the biophysical factors that were most influential to early forest development and that may override the negative effects of increasingly variable precipitation. This work contributes to refinements of species distribution models and can inform reforestation strategies intended to maintain biodiversity and ecosystem function under increasing climate extremes.

Perceptions of private practice dietitians regarding the collection and use of outcomes data in primary healthcare practices: A qualitative study

BACKGROUND

Dietitians working in private practices in primary settings provide nutrition care to support individuals with the prevention and management of chronic disease. A better understanding of the type and usage of data collected by dietitians in this setting may provide insights to optimise the effectiveness and impact of the workforce. The present study explored the perceptions of leading Australian private practice dietitians on the collection and usage of data in their practice.

METHODS

A qualitative descriptive study of Australian private practice dietitians, recruited by snowball sampling, was conducted on their perceptions and attitudes towards collecting and using data. Data were collected by semi-structured interviews and all interview data were thematically analysed.

RESULTS

Twenty-three dietitians participated. Five themes emerged: (i) collecting data is challenging, nuanced, unclearly defined and therefore not routinely carried out; (ii) consistent data collection processes are impeded by the diversity of practise and practices; (iii) business-related data collection is essential for sustainable dietetic services; (iv) clinical outcomes are fundamental to dietetic services; and (v) standardised, integrated systems are needed to enable routine data collection and synthesis.

CONCLUSIONS

Our findings demonstrate the rudimentary role business acumen has in practice viability and provides evidence to potentially re-shape the future of dietetic education in Australia. Private practice dietitians may benefit from tools and training that enable consistent collection of data about their services. Such data could enable benchmarking across the workforce and contribute to a broader understanding of dietetic impact on public health.

Tree rings reveal globally coherent signature of cosmogenic radiocarbon events in 774 and 993 CE

Though tree-ring chronologies are annually resolved, their dating has never been independently validated at the global scale. Moreover, it is unknown if atmospheric radiocarbon enrichment events of cosmogenic origin leave spatiotemporally consistent fingerprints. Here we measure the ¹⁴C content in 484 individual tree rings formed in the periods 770–780 and 990–1000 CE. Distinct ¹⁴C excursions starting in the boreal summer of 774 and the boreal spring of 993 ensure the precise dating of 44 tree-ring records from five continents. We also identify a meridional decline of 11-year mean atmospheric radiocarbon concentrations across both hemispheres. Corroborated by historical eye-witness accounts of red auroras, our results suggest a global exposure to strong solar proton radiation. To improve understanding of the return frequency and intensity of past cosmic events, which is particularly important for assessing the potential threat of space weather on our society, further annually resolved ¹⁴C measurements are needed.

Despite their extensive use, the absolute dating of tree-ring chronologies has not hitherto been independently validated at the global scale. Here, the identification of distinct ¹⁴C excursions in 484 individual tree rings, enable the authors to confirm the dating of 44 dendrochronologies from five continents.

Effects of dry period length on milk production and health of dairy cattle

Holstein cows (n = 781) in a commercial dairy herd were used in a randomized design to evaluate 2 dry period (DP) management strategies on milk production, milk components, milk quality, colostrum quality, and incidence of metabolic disorders. Cows were randomly assigned to a traditional 55 d (T) or shortened 34 d (S) DP. Cows assigned to T were fed a low-energy diet until 34 d before expected calving at which time all cows were fed a moderate-energy transition diet until calving. Postpartum, cows assigned to T produced more milk and tended to produce more solids-corrected milk than cows on S. Treatment differences in milk and solids-corrected milk yield were accounted for by cows in their second lactation. Milk fat percentage did not differ between treatments, but milk protein percentage was greater for cows assigned to S. Colostrum quality measured as IgG concentration did not differ between management strategies. Somatic cell score and cases of mastitis were not affected by management strategy. There was a tendency for prepartum nonesterified fatty acid (NEFA) to be lower for cows assigned to T compared with S. However, postpartum, cows assigned to S had significantly lower NEFA concentrations than those assigned to T. The incidences of ketosis, retained placenta, displaced abomasum, and metritis did not differ between treatments. Postpartum energy balance, as indicated by plasma NEFA, may have been improved for cows assigned to S; there was no detectable effect on animal health.

Influence of particle size on the effectiveness of the fiber in alfalfa silage

The objective was to determine the influence of alfalfa silage particle length on milk yield, milk composition, and chewing activity. Sixteen multiparous lactating Holsteins were used in each of two separate feeding trials over a 2-yr period providing two repetitions. Each trial was based on 4 x 4 Latin squares with 21-d periods. All four diets (2-yr average, dry basis) contained a basal level of 10.7% neutral detergent fiber from corn silage and 2.3% neutral detergent fiber from chopped alfalfagrass hay. One of the diets served as a low forage, low fiber control and contained only the basal forages. The other three diets contained an additional 8.6% neutral detergent fiber from coarser alfalfa silage, finely rechopped alfalfa silage or an equal mixture ofthe two. An increase in the forage content above the basal amount using alfalfa silage increased 4% fat-corrected milk yield, milk fat yield and concentration, eating time, and total chewing time. Dry matter intake was not influenced by diet. Linear increases in rumination and total chewing times were observed as the mean particle size of the alfalfa silage increased from finer to coarser. There was no linear effect of alfalfa silage particle size on milk yield, 4% fat-corrected milk yield, dry matter intake, or milk composition.

Effect of feeding a corn hybrid selected for leafiness as silage or grain to lactating dairy cattle

A leafy corn hybrid was compared to a grain corn hybrid as silage and high moisture grain to evaluate dry matter intake, milk yield, and milk composition. Sixteen multiparous Holstein cows averaging 97 DIM were used in a feeding trial based on 4 x 4 Latin squares with 21-d periods. Each of four diets contained (dry basis) 8% chopped hay, 42% corn silage, 11% high moisture corn grain, 10% whole, fuzzy cottonseed, and 29% protein concentrate. One diet used leafy corn as both high moisture grain and silage. A second diet contained grain corn hybrid (control) as both high moisture grain and silage. A third diet contained leafy corn for high moisture grain and control corn for silage and the fourth diet used control corn for high moisture grain and leafy corn for silage. Cows fed diets containing leafy silage produced more milk and milk protein and ate more DM than cows fed control silage. The corn hybrid used for high moisture grain did not influence milk yield or composition. Dry matter intake was greater for cows fed the diet containing both leafy high moisture grain and leafy silage than for cows fed both control high moisture grain and control silage, but milk yield and composition were not different. When fed as silage, the leafy corn hybrid used in this experiment supported greater DMI as well as higher milk and protein yields when compared to the grain corn hybrid.

Early chest radiographs in very low birth weight babies receiving corticosteroids for lung disease

We set out to determine whether chest radiographs obtained in premature infants between 9-16 days of age are predictive for the development of chronic lung disease of the newborn (CLD). This was a prospective cohort study. The study included 40 babies who were enrolled in a randomized trial of corticosteroid therapy for the prevention of CLD. Chest radiographs were obtained for clinical indications between 9-16 and 25-35 days of age. All chest radiographs were assessed by a single pediatric radiologist who was unaware of the treatment allocation and who used a previously published scoring system devised by Weinstein et al. [Pediatr Pulmonol 1994;18:284-289]. The radiographic score at 9-16 days correlated well with the radiographic score at 25-35 days of age (correlation coefficient, 0.69, P < or = 0.001). The scores at 9-16 days were significantly higher in those babies who had CLD at 28 days postnatal age (PNA) (P = 0.03) and at 36 weeks postmenstrual age (PMA) (P = 0.002). Using a receiver-operator characteristic curve, we have determined that for a radiographic score of 3 or greater at 9-16 days, the sensitivity for CLD was 0.64, and specificity was 0.84. We conclude that a chest radiograph taken between 9-16 days may help predict which at-risk preterm infants will develop CLD.

Influence of particle size on the effectiveness of the fiber in corn silage

This experiment evaluated the influence of particle size on the effectiveness of fiber in corn silage relative to that in hay crop, which consisted of mostly alfalfa silage. Fifteen multiparous Holstein cows were assigned to five treatments in each of 2 yr. The design was replicated but truncated 5 x 5 Latin squares with three 21-d periods in 1994 and four 21-d periods in 1995. The five diets (2-yr average, dry basis) were a basal, low fiber control with 12% neutral detergent fiber (NDF) from hay crop forage (60% of total diet NDF); a high fiber control with 22% NDF from hay crop forage (82% of total diet NDF); and three diets each containing 12% NDF from hay crop forage and 9% NDF from coarse corn silage, fine corn silage, or an equal mixture of the two. An increase in the forage content above the basal amount with either hay crop or corn silage increased rumination and total chewing time. No detectable differences in rumination, total chewing time, or milk fat concentration were detected among the corn silage diets. In yr 1, yield of milk components and dry matter intake were greater for cows fed the four low alfalfa diets, but there was no effect due to particle size of the corn silage. In yr 2, linear increases in milk, fat, and protein yields were observed as the mean particle size of the corn silage decreased. Reduction of corn silage particle size did not affect chewing behavior.

Influence of particle size on the effectiveness of beet pulp fiber

Sixteen Holstein cows in midlactation were used in a design based on a replicated 4 x 4 Latin square with the last period removed to determine the influence of particle size of beet pulp neutral detergent fiber (NDF) on its effectiveness as a replacement for alfalfa NDF. Diets were a low forage, low fiber diet [12.1 g of alfalfa NDF/100 g of dry matter (DM)], a normal forage diet (low forage plus 7.8 g of additional alfalfa NDF/100 g of DM), and two low forage diets with 5.3 g of NDF/100 g of DM from either whole or finely ground dried sugar beet pulp. Replacement of alfalfa fiber with beet pulp fiber increased milk protein yield because of the tendencies toward increased milk yield and protein concentration. However, milk fat concentration and yield were unaffected. The addition of beet pulp fiber, either whole or ground, to the basal low forage, low fiber diet did not affect yields of milk, protein, or fat, but milk protein concentration tended to be lower for cows fed the beet pulp diets than for cows fed the basal diet. Reducing the particle size of beet pulp increased DM intake but did not affect any of the milk yield measurements. Particle size reduction of beet pulp did not reduce its effectiveness as a fiber source as measured by changes in milk fat content.

Replacement of alfalfa neutral detergent fiber with a combination of nonforage fiber sources

Sixteen Holstein cows in midlactation were used in a 4 x 4 Latin square design to determine the effect of replacing alfalfa neutral detergent fiber (NDF), with NDF from a combination of whole linted cottonseed, dried distillers grains, and wheat middlings. The four diets were a basal control diet that was low in forage and fiber [(5.9 g of corn silage NDF and 6.1 g of alfalfa NDF/100 g of dry matter (DM)], a normal forage diet (low forage plus 10 g of additional alfalfa NDF/100 g of DM), and two low forage diets with either 5 or 10 g of NDF from the nonforage fiber sources added per 100 g of DM. Milk yield, milk protein yield, and milk protein percentage were higher, and milk fat percentage and fat yield were lower, for cows fed the low forage diets than for those fed the alfalfa control diet that was higher in fiber. Among the low forage diets, dry matter intake, milk fat percentage, and fat yield all increased linearly as NDF content increased. The ratio of acetate to propionate in the rumen and rumination times were greater for the normal forage control diet than for the high nonforage fiber diet. Added NDF from these nonforage fiber sources increased milk fat percentage and yield, but this increase was less than the NDF from alfalfa and less than predicted. In agreement with results of similar previous trials, milk protein yield and percentage were increased when alfalfa NDF was replaced with fiber from nonforage fiber sources.

Glucose transporters and in vivo glucose uptake in skeletal and cardiac muscle: fasting, insulin stimulation and immunoisolation studies of GLUT1 and GLUT4

Our aim was to study glucose transporters GLUT1 and GLUT4 in relation to in vivo glucose uptake in rat cardiac and skeletal muscle. The levels of both transporters were of a similar order of magnitude in whole muscle tissue (GLUT1/GLUT4 ratio varied from 0.1 to 0.6), suggesting that both may have an important physiological role in regulating muscle glucose metabolism. GLUT4 correlated very strongly (r2 = 0.97) with maximal insulin-stimulated glucose uptake (Rg' max., estimated using the glucose clamp plus 2-deoxy[3H]glucose bolus technique) in six skeletal muscles and heart. A distinct difference in regulation of the two transporters was evident in heart: in 5 h-fasted rats, basal glucose uptake and GLUT1 levels in heart were very high and both were reduced, by 90 and 60% respectively, by 48 h fasting. However, in heart (and in red skeletal muscle), neither GLUT4 levels nor Rg' max. were reduced by 48 h fasting. GLUT1 was shown to be specifically expressed in cardiac myocytes, because intracellular vesicles enriched in GLUT4 contained significant levels of GLUT1. In conclusion, the high association of muscle GLUT4 content with insulin responsiveness in different muscles, and the preservation of both with fasting, supports a predominant role of GLUT4 in insulin-mediated glucose uptake. GLUT1 may play an important role in mediating cardiac muscle glucose uptake in the basal metabolic state. Marked changes in GLUT1 expression with alterations in the metabolic state, such as prolonged fasting, may play an important role in cardiac glucose metabolism.

Effectiveness of neutral detergent fiber in whole cottonseed and dried distillers grains compared with alfalfa haylage

Sixteen Holstein cows in midlactation were used in a 4 x 4 Latin square design to determine the effect of replacing alfalfa NDF with NDF from whole, linted cottonseed or dried distillers grains. Low and high fiber control diets (13 and 19% of dietary DM from alfalfa haylage NDF, respectively) were compared with diets designed to contain 13% of DM from alfalfa haylage NDF plus 6% of DM from either cottonseed NDF or distillers grains NDF. Dry matter intake, milk yield, and milk protein yield were lower from the high fiber control diet. Milk fat percentage was lower for the low fiber control diet. The cottonseed diet was equal to the high fiber control diet in stimulating rumination. Rumen acetate to propionate ratio was higher for the high fiber control and cottonseed diets. Replacing alfalfa with either of these high fiber by-product feeds increased feed intake and yields of milk fat and protein. The effectiveness of the NDF in distillers grains and cottonseed was not significantly different from that of alfalfa NDF for maintaining milk fat yield. Whole cottonseed and dried distillers grains appear to be good sources of effective fiber for maintaining milk fat test when they are substituted for alfalfa haylage fiber in lactating cow rations.

Development of muscle insulin resistance after liver insulin resistance in high-fat-fed rats

Muscle and hepatic insulin resistance are two major defects of non-insulin-dependent diabetes mellitus. Dietary factors may be important in the etiology of insulin resistance. We studied progressive changes in the development of high-fat-diet-induced insulin resistance in tissues of the adult male Wistar rat. In vivo insulin action was compared 3 days and 3 wk after isocaloric synthetic high-fat or high-starch feeding (59 and 10% cal as fat, respectively). Basal and insulin-stimulated glucose metabolism were assessed in the conscious 5- to 7-h fasted state with the euglycemic clamp (600 pM insulin) with a [3-3H]-glucose infusion. Fat feeding significantly reduced suppressibility of hepatic glucose output by insulin after both 3 days and 3 wk of diet (P less than 0.01). However, a significant impairment of insulin-mediated peripheral glucose disposal was only present after 3 wk of diet. Further in vivo [3H]-2-deoxyglucose uptake studies supported this finding and demonstrated adipose but not muscle insulin resistance after 3 days of high-fat feeding. Muscle triglyceride accumulation due to fat feeding was not significant at 3 days but had doubled by 3 wk in red muscle (P less than 0.001) compared with starch-fed controls. By 3 wk, high-fat-fed animals had developed significant glucose intolerance. We conclude that fat feeding induces insulin resistance in liver and adipose tissue before skeletal muscle with early metabolic changes favoring an oversupply of energy substrate to skeletal muscle relative to metabolic needs. This may generate later muscle insulin resistance.

Effects of exercise training and dietary manipulation on insulin-regulatable glucose-transporter mRNA in rat muscle

Both exercise training and dietary manipulation (increasing omega-3/omega-6 fat ratio) can ameliorate insulin resistance caused by a high-fat diet in rats. We determined whether alterations in the expression of the insulin-regulatable (IR) and/or HepG2 glucose-transporter (GT) mRNAs were similarly affected. There was a significantly higher level of IRGT mRNA in skeletal muscle from exercise-trained versus sedentary high-fat-fed rats (27% increase, P less than 0.01). This difference is consistent with previously reported increases in muscle insulin-mediated glucose uptake. Skeletal muscle HepG2GT mRNA was too low to detect any training effect, but there was a tendency toward higher levels with training in cardiac muscle. In contrast, dietary manipulation, previously shown to lead to a much greater increase (100-300%) in muscle insulin-mediated glucose uptake, did not change IRGT or HepG2GT mRNA in skeletal muscle or heart. Thus, both dietary manipulation and exercise training increase insulin-stimulated glucose uptake in skeletal muscle, but only exercise training increases IRGT mRNA. Therefore, exercise training apparently increases GT production, whereas dietary manipulation improves glucose transport in skeletal muscle by other mechanisms.

Pentobarbital reduces basal liver glucose output and its insulin suppression in rats

Recent reports conflict on the effect that pentobarbital anesthesia has on basal glucose turnover in the rat. It is also unclear whether pentobarbital alters insulin suppressibility of hepatic glucose production (Ra). We examined these issues by performing basal and hyperinsulinemic euglycemic clamp studies in anesthetized and conscious animals. Ra and glucose utilization (Rd) were estimated using a steady-state infusion of 3-[3H]glucose. Pentobarbital anesthesia in normothermic rats transiently elevated plasma glucose but resulted in a sustained suppression of basal Ra (10.4 +/- 0.3 vs. conscious 13.2 +/- 0.9 mg.kg-1.min-1, P less than 0.05). In the insulin-stimulated state (110 mU/l), despite similar plasma glucose and insulin levels, clamp glucose infusion rate was significantly reduced in anesthetized animals (11.1 +/- 0.9 vs. conscious 23.6 +/- 1.3 mg.kg-1.min-1, P less than 0.001). This can be attributed to both a significantly lower insulin-stimulated Rd (15.4 +/- 1.3 vs. conscious 22.8 +/- 1.4 mg.kg-1.min-1, P less than 0.005) and reduced insulin suppression of Ra (4.3 +/- 0.8 vs. conscious -0.8 +/- 0.5 mg.kg-1.min-1, P less than 0.001; i.e., anesthetized 59% vs. conscious 100% reduction of basal Ra). Thus pentobarbital anesthesia significantly reduces basal Ra and induces hepatic insulin resistance (reduces Ra suppressibility). Pentobarbital effects are not dependent on induced hypothermia, but this exacerbates the metabolic perturbation. Caution should be used in extrapolating from the anesthetized to the conscious state.

Temporal changes in metabolites of prostanoids in milk of heifers after intramammary infusion of Escherichia coli organisms

A study was conducted to characterize the changes in the concentrations of three metabolites of prostanoids in the milk of a) heifers (n = 14; control) inoculated with Escherichia coli (E. coli) organisms into the udder and b) in heifers (n = 10; treatment) vaccinated with E. coli bacterin and treated similar to control heifers. Milk samples were obtained from the challenged quarter and analyzed for the concentrations of stable metabolites of thromboxane A2 (TXB2), prostacyclin (PCM) and prostaglandin E2 (PGEM) using radioimmunoassays. In control heifers milk TXB2 concentrations were significantly higher (P = 0.03) compared to treated heifers. Milk PCM concentrations increased significantly (P = 0.02) in control and treated heifers after the respective treatments, however, differences between the two groups were not significant. Milk PGEM concentrations also increased significantly (P = 0.02) in control and treated heifers after the respective treatments, and there were no differences between the two groups. Results of the present study suggest that, the prostanoids have a role in the pathophysiologic process of coliform mastitis.

Preparation and Nuclear Magnetic Resonance Study of Phosphorus Compounds Containing Alkenyl Functional Groups

The phosphines PPhn(CH2CH2CH=CH2)3−n, n = 2–0, PPhn(CH2CH2CH2CH=CH2)3−n, n = 1 or 2, and PPh2CH2CH = CH2 have been synthesized and studied by 1H and 31P magnetic resonance. The n.m.r. spectra of PPh2(OCH2CH=CH2), its oxide, O=PPh2(OCH2CH=CH2), and its Arbuzov rearrangement product, O=PPh2(CH2CH=CH2), have been investigated by 31P decoupling of the proton spectrum, selective proton decoupling of the 31P spectrum, and comparison with computer-simulated spectra to determine the spin–spin coupling constants. The n.m.r. spectra of the related oxides O=PPh2CH2CH2CH=CH2, O=P(CH2CH2CH=CH2)3, and O=P(OCH2CH=CH2)3 are also assigned. The data indicate that 3JPH > 2JPH for alkenylphosphines, 2JPH is larger for phosphine oxides than for phosphines, and 3JPH is little changed in comparing phosphorus(III) with phosphorus(V) compounds.