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PubMed2006

Estimates of residual dairy manure nitrogen availability using various techniques.

It is common practice to repeatedly apply dairy manure to the same fields. To accurately assess the total plant availability of manure nutrients, it is necessary to account for the nutrients remaining in soil from previous manure applications. A field experiment studying manure nitrogen (N) uptake by corn (Zea mays L.) was conducted from 1998 to 2003 on a Plano silt loam (fine-silty, mixed, mesic, Typic Argiudolls). Plots received two rates of semisolid manure either every year, every 2 yr, or every 3 yr to estimate first-, second-, and third-year dairy manure N residuals. Residual manure N availability was estimated from single and multiple manure applications using (i) the fertilizer N equivalence method, (ii) the apparent recovery (difference) method, (iii) relative effectiveness method, and (iv) recovery of (15)N-labeled manure. Second-year availabilities after a single manure application using the fertilizer equivalence, difference, and relative effectiveness methods were estimated to be 12, 8, and 4% of total manure N applications, respectively. Estimates of third-year availability by these methods were 3, 1, and 5%, respectively. Measurement of (15)N recovered from labeled manure was 6 and 2% in the second and third year, respectively. Fertilizer equivalence, difference, and relative effectiveness methods showed great year to year variability, reducing the confidence in the residual manure N availability estimates by these methods, but using (15)N-labeled manures reduced variability substantially. Based on this and other studies, we suggest that second- and third-year residual N availability from a single application of semisolid dairy manure would be 9 to 12%, and 3 to 5% of the original manure N application, respectively.

Animals↗

PubMed2006

Influence of the amount of dietary fiber on the available energy from hindgut fermentation in growing pigs: use of cannulated pigs and in vitro fermentation.

Available energy from hindgut fermentation to pigs fed various amounts of dietary fiber was investigated using an in vivo-in vitro methodology. Six growing pigs fitted with a simple T-shaped cannula at the terminal ileum, and following a Latin-square design, were fed 3 diets differing in the content of non-starch polysaccharides (NSP): a low fiber diet (LFD, 77 g/kg of DM), a standard fiber diet (SFD, 160 g/kg of DM), and a high fiber diet (HFD, 240 g/kg of DM). After adaptation to the diet for 10 d, samples from feces and ileum were collected and analyzed for DM, energy, NSP, and chromic oxide; feces were also analyzed for short chain fatty acids (SCFA). Freeze-dried ileal samples (10 g/L) were fermented in vitro in a fecal slurry consisting of an anaerobic mineral salt medium and feces (50 g/L) from cannulated pigs fed the same diets. Available energy was calculated from the amount of SCFA produced in vitro after 48 h of incubation. Nonstarch polysaccharide content in the fermented material was measured to assess the in vitro degradation of this fraction. Increasing dietary NSP from 77 to 240 g/kg of feed DM increased (P < 0.001) ileal flow from 199 to 468 g/kg of feed, leading to a reduction in the energy digested at the terminal ileum, from 15 to 11 MJ/kg of feed DM and an increment in energy digested in the hindgut, from 1.6 to 3.5 MJ/kg of feed DM. Total in vitro production of SCFA/kg of feed DM was dependent on the amount of ileal substrate available for fermentation; that is, increased concentrations of NSP in the diet led to an increase in the SCFA that may be available to the animal (P < 0.001). The molar ratio of SCFA produced in vitro was affected by diet; the high fiber diet showed the greatest (P = 0.004) proportion of acetic acid, and the low fiber diet showed a tendency (P = 0.081) to an increased butyric acid proportion compared with the other 2 diets. Net disappearance of NSP during fermentation in vivo and in vitro were compared and showed a close relationship (P < 0.001, slope = 0.906, r = 0.960). In our experimental conditions, available energy as SCFA to the animal from hindgut fermentation increased with the concentration of dietary NSP (P < 0.001) and provided between 7.1 and 17.6% of the total available energy.

Animal Feed↗

PubMed1990

Subjective, social, and physical availability. I. Their interrelationships.

The alcohol availability literature suggests that physical conditions which restrict alcohol availability reduce rates of alcohol consumption. Smart (1980) argued that the availability construct should be expanded to include subjective and social components. It was hypothesized that people who perceived alcohol to be subjectively and socially available would consume more alcohol than those who did not and that physical availability would only indirectly affect consumption. These hypotheses were examined using data from a telephone survey. In Part I, the interrelationships between physical, subjective, and social availability are described. In Part II (this journal, Vol. 25, No. 9), the relationships between these variables and alcohol consumption are explored.

Adult↗

PubMed1999

An update of antidote availability in veterinary medicine.

Lack of commercially available antidotes for animals is an issue of significant concern to the American Board of Veterinary Toxicology. A few antidotes are available for food animals through extra-label use, regulatory discretion and compounding. However, regulatory restrictions arising from human food, safety concerns have limited the availability of food animal antidotes. Use of some antidotes in food animals requires establishment of an investigational new animal drug application. Antidotes are generally more available for non-food animals from several sources: approved animal drugs, extra-label use of approved animal and human drugs, regulatory discretion and compounding. Present alternatives are discussed as well as the need for legislation to increase antidote availability. Human food safety will always be an issue for food animal antidotes. Future availability of non-food animal and food animal antidotes will depend on several mechanisms and may include the establishment of veterinary antidote depots. Stakeholders are encouraged to participate in identifying and implementing these mechanisms.

Animal Husbandry↗

PubMed2001

The effect of phosphorus availability on the carbon economy of contrasting common bean (Phaseolus vulgaris L.) genotypes.

A common response to low phosphorus availability is increased relative biomass allocation to roots. The resulting increase in root:shoot ratio presumably enhances phosphorus acquisition, but may also reduce growth rates by diverting carbon to the production of heterotrophic rather than photosynthetic tissues. To assess the importance of increased carbon allocation to roots for the adaptation of plants to low P availability, carbon budgets were constructed for four common bean genotypes with contrasting adaptation to low phosphorus availability in the field ("phosphorus efficiency"). Solid-phase-buffered silica sand provided low (1 microM), medium (10 microM), and high (30 microM) phosphorus availability. Compared to the high phosphorus treatment, plant growth was reduced by 20% by medium phosphorus availability and by more than 90% by low phosphorus availability. Low phosphorus plants utilized a significantly larger fraction of their daytime net carbon assimilation on root respiration (c. 40%) compared to medium and high phosphorus plants (c. 20%). No significant difference was found among genotypes in this respect. Genotypes also had similar rates of P absorption per unit root weight and plant growth per unit of P absorbed. However, P-efficient genotypes allocated a larger fraction of their biomass to root growth, especially under low P conditions. Efficient genotypes had lower rates of root respiration than inefficient genotypes, which enabled them to maintain greater root biomass allocation than inefficient genotypes without increasing overall root carbon costs.

Biomass↗

PubMed2001

Effect of phosphorus availability on basal root shallowness in common bean.

Root gravitropism may be an important element of plant response to phosphorus availability because it determines root foraging in fertile topsoil horizons, and thereby phosphorus acquisition. In this study we seek to test this hypothesis in both two dimensional paper growth pouch and three-dimensional solid media of sand and soil cultures. Five common bean ( Phaseolus vulgaris L.) genotypes with contrasting adaptation to low phosphorus availability were evaluated in growth pouches over 6 days of growth, and in sand culture and soil culture over 4 weeks of growth. In all three media, phosphorus availability regulated the gravitropic response of basal roots in a genotype-dependent manner. In pouches, sand, and soil, the phosphorus-inefficient genotype DOR 364 had deeper roots with phosphorus stress, whereas the phosphorus-efficient genotype G19833 responded to phosphorus stress by producing shallower roots. Genotypes were most responsive to phosphorus stress in sand culture, where relative root allocation to the 0-3- and 3-6-cm horizons increased 50% with phosphorus stress, and varied 300% (3-6 cm) to 500% (0-3 cm) among genotypes. Our results indicate that (1) phosphorus availability regulates root gravitropic growth in both paper and solid media, (2) responses observed in young seedlings continue throughout vegetative growth, (3) the response of root gravitropism to phosphorus availability varies among genotypes, and (4) genotypic adaptation to low phosphorus availability is correlated with the ability to allocate roots to shallow soil horizons under phosphorus stress.

Biomass↗

PubMed2001

Portuguese household food availability in 1990 and 1995.

OBJECTIVE: To examine the changes in Portuguese household food availability from 1990 to 1995. DESIGN: Using the DAta Food NEtworking (DAFNE) classification scheme for nutritional and socio-economic variables, data from the Portuguese Household Budget Surveys collected in 1989/90 and 1994/95 were analysed. The mean availability (quantity person(-1) day(-1)) for the total population, by locality and by level of education of the household head, was computed for each of the main food and beverage groups. SETTING: Portugal, 1989 to 1995. RESULTS: Although still among one of the countries with high availability of cereals, pulses, fish and seafood and olive oil, Portugal is gradually moving away from the traditional 'Mediterranean diet'. Between 1989 and 1995, the availability of complex carbohydrates and olive oil was reduced, while the availability of protein-supplying food groups increased. Considerable disparities can be observed by locality and by the level of education of the household head. Households in urban areas and of higher socio-economic status are the main actors of the changes in 'traditional' food habits. CONCLUSION: Although these findings are based on household food availability rather than consumption, they indicate the direction of the changes taking place in the Portuguese diet and can be used effectively by agriculture specialists, nutrition experts and policy makers.

Adolescent↗

PubMedDate not supplied

[Evaluation of the availability, utilization, and costs of computerized tomography in the state of Morelos, Mexico].

OBJECTIVE: To assess the availability, utilization, and costs of computerized tomography (CT scan) in private and public hospitals in Morelos State, Mexico. MATERIAL AND METHODS: From January to April 1999, a cross-sectional study was carried out in two private and two public hospitals in Morelos, Mexico. Individual face-to-face interviews were conducted with directors, managers, radiologists, and heads of maintenance at each hospital. Statistical analysis was performed to describe the variables measuring availability, utilization, and costs of CT scans. A comprehensive assessment of CT scans was also performed. Emphasis was made on the variability of observed patterns among the participating hospitals. RESULTS: CT scan technology has been used by hospitals in Morelos State for over ten years; programs for preventive or corrective maintenance of these equipments are available, although at high costs. No strategies for technology assessment are available for acquisition of CT scanners nor during their period of utilization. This study did not attempt to evaluate the appropriateness of the clinical use of CT nor its untoward effects. CONCLUSIONS: Findings from the present study showed that: 1) a lack of mechanisms for technology assessment and management of CT scans prevented hospitals from managing CT scanning technologies efficiently; 2) technology assessment regulation is not available, even though it is necessary for the adequate selection of the best technologies, on the basis of their efficiency, effectiveness, safety, and availability.

Cross-Sectional Studies↗

PubMed2002

Availability of resources of diabetic care in primary health care settings in Aseer region, Saudi Arabia.

OBJECTIVE: The objective of this study is to evaluate the availability of resources of diabetes care in primary health care settings in Aseer region, Southwest, Kingdom of Saudi Arabia. METHODS: This study was conducted during September 2001 by distributing a questionnaire to all technical directors of primary health care centers (PHCCs) in Aseer region. The questionnaire, designed by the authors, contained 6 sections that dealt with the necessary structures of diabetic care in the region in addition to the data base of PHCC such as served population, distance from the hospital, and total working physicians and nurses at the PHCC. The data from the questionnaire was entered and analyzed using Statistical Package for Social Sciences. RESULTS: Two hundred and forty-two PHCC technical directors responded to the questionnaire. Total served population by PHCC was 970,306 individuals. Total working physicians were 391 and nurses were 902. Diabetics represented 2.7% of the total served population. More than 90% of PHCCs have diabetic files, registers, appointment system and protocol for diagnosis and treatment of diabetes. Oral hypoglycemic agents were always available at 55% of PHCCs while metformin was not available at 52% of PHCCs. Diabetic identification cards were available in 80.4% of PHCCs while the health education means were less available, except for health education programs was available at 97.5% of PHCCs. At least, 40% of PHCCs were provided financially or by different means of health education through community health committees. CONCLUSION: This study revealed that resource items for diabetic care are inadequate in particular drugs and laboratory facilities. Establishment of a diabetes committee in Aseer region is a priority in order to manage such shortages and to plan, supervise and coordinate the diabetic care in the region.

Diabetes Mellitus↗

PubMed2003

[Soil water availability in new-cultivated hillside land].

The dynamics of water content in three soil layers (0-20 cm, 20-40 cm and 40-60 cm) were determined at three geographic locations (mesoslope, downgrade, valley) of new-cultivated sugarcane field and uncultivated hillside land at one day before rain, 4 hours, 2, 4, 6 and 8 days after rain during rainy season and dry season in 1998 at environmental immigrants settlement area of northwest Guangxi. The result showed that the increment of available soil water content in valley sugarcane field after rain was equal to precipitation, but that in mesoslope sugarcane field and uncultivated hillside land was 80% of precipitation. The distribution of available soil water content in 0-60 cm soil horizons was uniform after rain during rainy season; however it was concentrated in surface horizon after rain during dry season. The differences of available soil moisture saturation degree between treatments and between soil horizons were significant during rainy season; nevertheless, those of dry season were not significant. The consumption rate of available soil water content in 0-60 cm soil horizons of uncultivated hillside land was the least among all treatments. Although the consumption rate of available soil water content during dry season was less than that of rainy season, the available soil water content during dry season would be exhausted in 15 days after rain.

Crops, Agricultural↗

PubMed1992

Effect of processing on availability of essential amino acids in rice flour and cooked rice.

The availability of nitrogen, lysine and nine essential amino acids was determined in rice flour and cooked rice. Lysine availability was determined by the growth response method using regression analysis of body weight gain or moisture gain against lysine consumed from rice flour and cooked rice. The results show a good correlation between lysine consumed and weight gain or moisture gain (r = 0.86 + 0.8) for rats fed cooked rice and fair correlation for those fed rice flour. The results of lysine availability show that cooking increases availability by both ways of calculation. The availability of nitrogen and of essential amino acids was also determined by the balance trial method with rats. Results of balance trial show that cooking has no significant effect on essential amino acids availability. Data for weight gain, food efficiency and PER were significantly decreased by cooking.

Amino Acids, Essential↗

PubMed2003

Can I find a doctor? Availability of primary care physicians in the San Francisco Bay Area.

OBJECTIVES: Primary care physicians function as "gatekeepers" in many managed care systems. With the rapid growth of managed care enrollment, it is crucial that patients have adequate access to primary care physicians. We investigated factors associated with new-patient appointment availability of primary care physicians in the San Francisco Bay Area. STUDY DESIGN: Observational cohort. POPULATION: Cross-sectional survey of primary care physician offices in 2 San Francisco Bay Area counties (n=438). OUTCOMES MEASURED: New-patient appointment availability. RESULTS: Seventy-five percent of primary care physicians participating in managed care had an appointment available for a new patient. Appointments were more likely to be available with primary care physicians who had been in practice for 10 years or less (odds ratio [OR]=4.2; 95% confidence interval [CI], 1.7-10.3), compared with more established physicians; and with primary care physicians who had graduated from a medical school outside of the United States (OR=3.5; 95% CI, 1.7-7.3), compared with US graduates. Appointments within 30 days were less available with female primary care physicians (OR=0.4; 95% CI, 0.2-0.7) than for male primary care physicians. CONCLUSIONS: The limited availability of appointments for new patients may create barriers to primary care in the San Francisco Bay Area, a region with high managed-care penetration.

Age Factors↗

PubMed2004

Ascorbic acid and mineral availability in two Nigerian plant foods.

This paper reports the effect of various concentrations of ascorbic acid on the availability of Fe, Zn, Ca and Mg in two popular plant foods--cowpea and amaranthus vegetable--in Nigeria. Ascorbic acid enhancement of iron availability was over 300 % and zinc by 200 % from 0-100 mg concentration. Availability of iron was further increased by 200 mg ascorbic acid in amaranthus but showed a 50 % decrease in the legume. Availability of zinc was decreased by 200 mg ascorbic acid but to different levels in both plant foods. In the legume, maximum enhancement of Ca and Mg availability was exhibited at 100 mg ascorbic acid level but suppressed at higher concentrations. In amaranthus, maximum Ca enhancement was exerted by 200 mg ascorbic acid and 50 mg for Mg. Enhancement of Cu in the legume was marginally affected by ascorbic acid concentrations while inhibition of Cu was observed in amaranthus between 50-300 mg ascorbic acid concentrations. The effect of ascorbic acid on the availability of minerals seems to be concentration dependent and varies with theplant food.

Amaranthus↗

PubMed2004

Food cost and availability in a rural setting in Australia.

INTRODUCTION: The burden of chronic diseases is rapidly increasing worldwide. In Australia rural populations have a greater burden of disease. Chronic diseases are largely preventable with diet as a key risk factor. With respect to diet-related chronic disease, dietary risk may be due to poor food access, namely, poor availability and/or the high cost of healthy food. It is likely that poor food access is an issue in rural areas. OBJECTIVE: To assess food access in rural south-west (SW) Victoria, Australia. METHODS: A total of 53 supermarkets and grocery stores in 42 towns participated in a survey of food cost and availability in the rural area of SW Victoria. The survey assessed availability and cost of a Healthy Food Access Basket (HFAB) which was designed to meet the nutritional needs of a family of 6 for 2 weeks. RESULTS: Seventy-two percent of the eligible shops in SW Victoria were surveyed. The study found that the complete HFAB was significantly more likely to be available in a town with a chain-owned store (p <0.00). The complete HFAB was less likely to be available from an independently owned store in a town with only one grocery shop (p <0.004). The average cost of the HFAB across SW Victoria was AU380.30 dollars +/- 25.10 dollars (mean +/- SD). There was a mean range in difference of cost of the HFAB of 36.92 dollars. In particular, high variability was found in the cost of fruits and vegetables. CONCLUSIONS: Cost and availability of healthy food may be compromised in rural areas. IMPLICATIONS: Improvements in food access in rural areas could reduce the high burden of disease suffered by rural communities.

Journal Article↗

PubMed2005

In vitro methods for the evaluation of drug availability from suppositories: comparison between biological and artificial membranes.

Drug availability from suppositories is currently evaluated in vitro by means of a model consisting of a dialysis tube (porous membrane) or isolated biological membrane (animal rectum). We propose a new alternative in vitro method to determine drug availability from suppositories consisting of an artificial membrane soaked with n-octanol, coupled with a filter paper sheet soaked with phosphate buffer. This method provides for an integrated hydro-lipophilic simulation of the biological membrane, including the mucus layer adhering to the rectal mucosa. By simply using the porous membrane, the amount of drug released varied directly according to its solubility for formulations with lipophilic excipients. For formulations with hydrophilic excipients, drugs with low/intermediate solubility in water showed increased availability in comparison to lipophilic excipients. The in vitro rat rectum model provided overall results that were similar to those obtained with the porous membrane method, although the percentage values of AUC were lower. The new model of in vitro simulated absorption produced a degree of drug availability that was lower in comparison to both previous methods. However, the simulated model appeared to give a pattern of drug availability closer to that of the model of in vitro rat rectum. The new in vitro artificial model thus appears to be useful in suppositories preformulation studies, allowing for an estimate of drug availability and the choice of the most adequate excipient.

Algorithms↗

PubMed1978

[Measure of available and blocked lysine in industrial milks].

The classical methods to measure lysine availability give rise to some difficulties in milks due to the presence of deoxyketose-lysine (DOKL). Six methods, one of which measuring the blocked lysine, are studied. Amino acid chromatography gives a too high value of lysine when it is blocked as DOKL, the latter regenerating lysine during acid hydrolysis. The determined lysine does not correspond to the available one. Fluro-dinitro-benzene is not fully specific for free epsilon-NH2 of lysine and the reducing sugars present interfere during the reaction in converting "nitro" into "amino" groups. Guanidization is a specific reaction between the epsilon-NH2 of lysine and O-methyl-isourea with formation of homoarginine. The homarginine, calculated as lysine corresponds to the available lysine. Reduction with sodium borhydride converts the DOKL to a stable compound which, during acid hydrolysis, does not regenerate lysine and does not form furosine. The recovered lysine corresponds to the available one. Our "in vitro" digestion method with simultaneous dialysis enables the determination of available lysine, as the proteolytic enzymes used do not split up the DOKL binding. The liberated lysine corresponds to the available one. The blocked lysine is measured from furosine after acid hydrolysis. A formula, which makes up the level of furosine formation and for lysine regeneration from DOKL, is established.

Amino Acids↗

PubMed1982

Noninvasive assessment of portal-systemic shunting: evaluation of a method to investigate systemic availability of oral glyceryl trinitrate by digital plethysmography.

The systemic availability of oral glyceryl trinitrate may be a measure of the fraction of portal blood bypassing the hepatocytes through portal-systemic shunts. In order to test this hypothesis without the need for blood sampling, measurements of drug concentrations in plasma were replaced by assessments of pharmacologic effects by using digital plethysmography. Dose-response curves resulting from graded intravenous infusions of glyceryl trinitrate (8 and 25 microgram/min) were used as standard of comparison for the pharmacologic response resulting from an oral dose of 800 microgram. In 9 normal volunteers, systemic availability of oral glyceryl trinitrate was 2 +/- 4% SD. In 7 patients with end-to-side portacaval shunts it was 94 +/- 18%, in 3 patients with distal splenorenal shunts 57 +/- 11%, and in 10 patients with cirrhosis of the liver it varied between 15% and 85%. Systemic availability of glyceryl trinitrate was negatively correlated with the initial plasma disappearance rate of sulfobromophthalein (r = -0.72, p less than 0.01). No significant correlation was found with the galactose elimination capacity (r = -0.12, n = 17). The lack of systemic availability of glyceryl trinitrate in healthy volunteers together with an availability close to 100% after end-to-side shunts is compatible with a very high hepatic extraction of the test compound by the normal liver, and with the idea that the systemic availability of of oral glyceryl trinitrate comes close to representing portal-systemic shunting. The procedure is rapid, essentially noninvasive, and well tolerated by patients.

Administration, Oral↗

PubMed1997

General practitioners' views on the over-the-counter availability of H2-antagonists.

BACKGROUND: In recent years there has been a trend towards increasing the number of drugs that are available over the counter (OTC) without prescription. Simultaneously, community pharmacists have been encouraged to develop and extend their role. General practitioners (GPs) have been shown to have some reservations about these developments. A group of drugs widely used in general practice, the H2-antagonists, have recently become available OTC. AIM: To examine GPs' attitudes towards community pharmacists dispensing H2-antagonists over the counter (OTC) without prescription. METHOD: Postal questionnaire to a sample of GPs from inner and outer London, Surrey, Kent, Hampshire, Northumberland, Newcastle upon Tyne and Leicestershire. RESULTS: Of 850 questionnaires sent, 515 were returned, an overall response rate of 60.5%. Fifty four per cent of respondents agreed that cimetidine should be available over the counter for dyspepsia in adults under 45 years not responsive to antacids. Ninety per cent of respondents were aware that H2-antagonists had been deregulated. Most general practitioners learned about the deregulation from professional journals. Very few GPs stated they had changed their prescribing practice since H2-antagonists became available OTC. The high cost to the patient of the OTC product was the most frequently mentioned reason why respondents did not encourage their patients to switch from prescription to OTC H2-antagonists. Worries and concerns regarding the OTC availability of H2-antagonists included masking serious conditions, missed diagnosis, loss of control by the GP and the potential for inappropriate use by patients. CONCLUSIONS: Since 1990, there has been a large increase in GPs support for the OTC availability of cimetidine. However, according to their stated behaviour, the reclassification of H2-antagonists does not seem to have changed GPs' prescribing practice, and few appear to be recommending that their patients buy them over the counter.

Adult↗