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PubMed2002

A state-wide assessment of the obstetric, anesthesia, and operative team personnel who are available to manage the labors and deliveries and to treat the complications of women who attempt vaginal birth after cesarean delivery.

OBJECTIVE: The purpose of this study was to determine on a state-wide basis the range of obstetric, anesthesia, and surgical team personnel who were available immediately to manage the labors and deliveries of women who attempted vaginal birth after cesarean delivery. Additionally, we tried to determine whether hospitals had stopped performing vaginal births after cesarean delivery or made changes in their policies regarding vaginal birth after cesarean delivery as a result of recent American College of Obstetricians and Gynecologists recommendations. STUDY DESIGN: Available immediately was defined as "being present in the hospital." All hospitals that provided obstetric care in the State of Ohio were surveyed to determine whether an obstetrician with cesarean privileges, an anesthesiologist, or an anesthetist capable of independently administering anesthesia for a cesarean section, and a surgical team were available immediately when women attempted vaginal birth after cesarean delivery. The hospitals were also asked whether they had stopped allowing vaginal births after cesarean delivery or had made changes in their vaginal birth after cesarean delivery policies in response to the recent recommendations of the American College of Obstetricians and Gynecologists. Data were computerized and analyzed by the chi(2) test. RESULTS: Seventy-seven (93.9%), 35 (100%), and 13 (100%) of level I, II, and III hospitals performed vaginal births after cesarean delivery. An obstetrician was immediately available in 27.3%, 62.9%, and 100% of level I, II, and III institutions, respectively (P <or=.001). Anesthesia availability was 39%, 100%, and 100% of level I, II, and III institutions, respectively (P <or=.001). A surgical team was available in 35.1%, 97.1%, and 100% of level I, II, and III hospitals, respectively (P <or=.001). A complete complement was available in 15.6%, 62.9%, and 100% of level I, II and III institutions, respectively (P <or=.001). Two hospitals had stopped the performance of vaginal births after cesarean delivery, and 10 additional hospitals were considering stopping the performance of vaginal births after cesarean delivery. Policy changes had been adopted in 15 institutions, and 4 other institutions were considering changes. CONCLUSION: Most level I and many level II hospitals provide less than optimum staffing when women are attempting vaginal birth after cesarean delivery. Because vaginal births after cesarean delivery are equally distributed among level I, II, and III institutions in this state, many women may be attempting vaginal birth after cesarean delivery under less than optimal conditions. The data suggest the need for changes in staffing or referral patterns to safely meet the Healthy People 2010 goal of increasing the vaginal birth after cesarean delivery rate nationally.

Anesthesia, Obstetrical↗

PubMed1981

Availability of lysine in vegetable protein concentrates as determined by the slope-ratio assay with growing pigs and rats and by chemical techniques.

1. The availability of lysine in seven vegetable protein concentrates was determined using the slope-ratio assay with growing pigs and rats and with two chemical techniques. 2. With pigs, estimates of availability were lower using carcass compared to live-weight values, but there was no consistent effect of including food intake in the criterion of response. Availability estimates, using food conversion efficiency on a carcass basis were (proportion of total) linseed meal -0 . 23, lupin-seed meal 0 . 74, rapeseed meal no. 1 0 . 97, no. 2 0 . 77, sunflower meal no. 1 0 . 59, no. 2 0 . 66, no. 3 0 . 54. 3. Availability estimates for lysine with rats were also lower using carcass compared to live-weight values. Estimates based on food conversion efficiency were higher than those based on weight gain. Availability estimates in lupin-seed meal and sunflower meals were in general agreement with the pig estimates, whilst that with linseed meal was considerably higher (0 . 82). Assays were not conducted with rapeseed meal due to problems of food rejection with this meal. 4. The differences in available lysine were not detected by the chemical Silcock available-lysine test (Roach et al. 1967) nor by the direct fluoro-dinitrobenzene procedure (Carpenter, 1960).

Animals↗

PubMed1985

Nutritional availability of methionine, lysine and tryptophan in fish meals, as assessed with biological, microbiological and dye-binding assay procedures.

In vitro assay procedures were applied in the measurement of available amino acids in a selection of fish meals representing good- and poor-quality product. Results were assessed by comparing them with results from chick-growth assays. Available methionine and tryptophan were assayed microbiologically with Streptococcus zymogenes, after predigestion of the test samples with papain or pronase. Results for methionine were correlated with chick-growth assays (r 0.86 for papain, 0.91 for pronase; P less than 0.01). Compared with the chick assays, papain tended to give lower, and pronase higher, results. Finer milling of the test samples did not influence the pronase values. Results for available tryptophan were also correlated with chick-growth assays (r 0.95 for papain, 0.96 for pronase; P less than 0.001). Compared with the chick values, papain gave markedly lower results and pronase marginally higher ones. Finer milling of the test samples increased the papain values by about 50% but had no effect with pronase. Available lysine was assayed microbiologically with Tetrahymena pyriformis and with a dye-binding procedure (DBL). The results correlated with the chick-growth assays (r 0.99 for DBL, P less than 0.001; 0.85 for Tetrahymena, P less than 0.01) but both methods overrated the poorer-quality samples. True nitrogen digestibilities and amino acid digestibilities were determined with chickens by the 'ileal analysis' procedure: the amino acid digestibilities were significantly higher and similar to the corresponding availabilities as measured in chick-growth assays. Ball milling a poor-quality fish meal caused a marked fall in its N digestibility, whereas similar treatment of a good-quality meal caused a slight increase. An explanation for this finding is proposed. Strep. zymogenes assays following pronase digestion of the test samples gave precise and acceptably accurate measures of the biologically available methionine and tryptophan in the test samples. For available lysine, Tetrahymena and DBL values for the poorer-quality samples were notably higher than the chick-growth assay; possible reasons for this are discussed. The ileal analysis procedure underestimated true N digestibility.

Animals↗

PubMed1987

Relative nutritional availability to rats of selenium in Finnish spring wheat (Triticum aestivum L.) fertilized or sprayed with sodium selenate and in an American winter bread wheat naturally high in Se.

A Finnish national programme to fertilize crops with sodium selenate led us to compare the nutritional availability to rats of selenium in two Finnish spring wheats (Triticum aestivum L.), either fertilized or sprayed with sodium selenate, with that in an American winter bread wheat naturally high in Se. Weanling male rats were given a Se-deficient Torula yeast diet for 4 weeks followed by either continued depletion or repletion for 4 weeks with graded levels of Se as sodium selenite (standard) or wheat (test food). Plasma and liver Se levels and plasma and liver glutathione peroxidase (EC 1.11.1.9; GSH-Px) activities were used as criteria of body Se status. The availability of Se under these conditions was calculated with the point-slope technique at two dietary levels of Se (Expt 1) and with the slope-ratio method (Expt 2). In the point-slope assay, the level of dietary Se fed had a considerable effect on the apparent availability values obtained which made interpretation of the results difficult. In the slope-ratio assay, no difference in the availability of Se from the various wheats was observed when plasma or liver Se levels were used as the response criteria. The Se in the fertilized wheat was somewhat more available than that in the sprayed wheat when plasma or liver GSH-Px activities were the response criteria. Overall, availability values (%) derived by averaging all four response criteria were 86, 77 and 73 for the fertilized and sprayed Finnish wheats and the American wheat respectively (sodium selenite 100). These results show that wheat is a relatively available source of Se to rats regardless of whether its Se content is naturally high or is increased by fertilization or spraying.

Animals↗

PubMed1992

A method for estimating the available energy of incompletely digested carbohydrates in rats.

We developed a method to estimate the available energy from carbohydrates that are unavailable or partially unavailable through direct digestion and absorption. Radiolabeled bacterial and plant cellulose and polydextrose were administered orally to germfree and conventional rats. Label in breath, feces, intestinal contents and carcass were determined with excellent total recovery of the administered label. Comparison of these measurements in germfree and conventional rats was used to calculate the energy directly available by digestion and that available only after fermentation. Although the method overestimates available energy because of the more efficient digestive metabolism of the germfree rat, it provides a reliable, maximum energy value based upon fewer assumptions than previous methods. In conventional rats, 65% of the administered cellulose and 54% of the administered polydextrose were recovered in feces. In conventional rats, appreciable amounts of cellulose were fermented and an available energy value of 3.5 kJ/g was calculated. Calculation of the total availability of polydextrose, taking into account the direct absorption of small amounts of monomers present and the efficiency of fermentation, indicates an available energy value of 4.7 kJ/g.

Administration, Oral↗

PubMed2002

Availability and usability of data for medical practice assessment.

OBJECTIVE: We analyzed availability and usability of the electronic patient data required for assessment of medical practice for a specific patient group. DESIGN: Case study in which physicians defined performance indicators and additional exploratory information. Data availability in the hospital information system was determined. Data usability was evaluated based on reason for recording, administrative procedures, and comparison with paper data. SETTING: A 155 bed pediatric department in a public academic medical center. STUDY PARTICIPANTS: Pediatricians and children with suspected meningitis. MAIN OUTCOME MEASURES: Availability and usability of electronic patient data. Usability criteria were standardization, completeness, and accuracy. RESULTS: A total of 14 performance indicators were defined. Of 39 data items required for indicator quantification, 29 were available, and 19 were usable without manual handling. Completeness and accuracy of the registration of reason for admission and discharge diagnoses were insufficient, leading to problematic patient selection and complication detection. Time-points of patient events were inaccurate or not available. Data regarding outpatient diagnosis, signs and symptoms, indications for test ordering, and medication administration were missing. Test result reports were not adequately standardized. Based on electronic patient data, five out of 14 performance indicators could be quantified reliably, but only after patient selection problems were overcome. For exploratory information, 16 out of 25 required data items were available and 13 were usable. CONCLUSIONS: Availability and usability of electronic patient data are insufficient for physician-led and detailed assessment of medical practice for specific patient groups. Extended registration of the reason for admission will improve patient selection and assessment of diagnostic process.

Academic Medical Centers↗

PubMed2001

Growth and dry-matter partitioning of young Populus trichocarpa in response to carbon dioxide concentration and mineral nutrient availability.

Young individuals of a single black cottonwood (Populus trichocarpa Torr. & Gray) clone were raised for three growing seasons in whole-tree chambers and exposed to either ambient or elevated atmospheric carbon dioxide concentration ([CO2]), with either a high or a low mineral nutrient supply, in a factorial experimental design. Nutrient availability had a larger effect on growth and dry matter partitioning than did [CO2]. Total biomass did not differ significantly with CO2 treatment when nutrient availability was low. However, elevated [CO2] increased whole-plant biomass by 47% in the high nutrient availability treatment. Carbon dioxide enrichment reduced leaf area ratio and specific leaf area significantly, but had no significant effect on mean leaf size or leaf mass ratio. Root mass ratio was significantly increased by elevated [CO2] at low, but not at high nutrient availability. A modified "demographic harvesting approach" made possible the retrospective estimation of stem and branch dry masses for different years. The relative growth rates of stem and branch were significantly enhanced by elevated [CO2] with high, but not with low nutrient availability. Canopy productivity index (CPI), i.e., the amount of stem and branch wood produced annually per unit leaf area, was raised 12% by elevated [CO2] when nutrient availability was high, but was reduced when nutrient availability was low, because of increased below ground allocation.

Biomass↗

PubMed1996

Comparison of two compartmental models for describing receptor ligand kinetics and receptor availability in multiple injection PET studies.

The goal of research with receptor ligands and PET is the characterization of an in vivo system that measures rates of association and dissociation of a ligand-receptor complex and the density of available binding sites. It has been suggested that multiple injection studies of radioactive ligand are more likely to identify model parameters than are single injection studies. Typically, at least one of the late injections is at a low specific activity (SA), so that part of the positron emission tomography (PET) curve reflects ligand dissociation. Low SA injections and the attendant reductions in receptor availability, however, may violate tracer kinetic assumptions, namely, tracer may no longer be in steady state with the total (labeled and unlabeled) ligand. Tissue response becomes critically dependent on the dose of total ligand, and an accurate description of the cold ligand in the tissue is needed to properly model the system. Two alternative models have been applied to the receptor modeling problem, which reduces to describing the time-varying number of available receptor sites. The first (Huang et al., 1989) contains only compartments for the hot ligand, 'hot only' (HO), but indirectly accounts for the action of cold ligand at receptor sites via SA. The second stipulates separate compartments for the hot and cold ligands, 'hot and cold' (HC), thus explicitly calculating available number of receptors. We examined these models and contrasted their abilities to predict PET activity, receptor availability, and SA in each tissue compartment. For multiple injection studies, the models consistently predicted different PET activities--especially following the third injection. Only for very high rate constants were the models identical for multiple injections. In one case, simulated PET curves were quite similar, but discrepancies appeared in predictions of receptor availability. The HO model predicted nonphysiological changes in the availability of receptor sites and introduced errors of 30-60% into estimates of B'max for test data. We, therefore, strongly recommend the use of the HC model for all analyses of multiple injection PET studies.

Animals↗

PubMed2003

Using the cue-availability paradigm to assess cue reactivity.

BACKGROUND: A recent meta-analysis on cue-reactivity research revealed that cue-specific craving for alcohol is substantially less robust than craving measured for other drugs of abuse. The small effect sizes for alcohol underscore the need for more powerful methods of assessing cue reactivity in humans. The cue-availability paradigm is a modification of the conventional cue-reactivity paradigm and is intended to increase the sensitivity of measuring cue-reactivity to alcohol in humans. METHODS: Seventeen non-treatment-seeking alcoholics were tested individually on two different sessions (after priming with alcohol and after priming with placebo-alcohol). Subjects were presented with a total of 32 cue-availability trials. On each trial, subjects were presented with either a target cue (alcohol) or a neutral cue (water). Each cue was available for drinking on 50% of the trials (availability condition). Cue-reactivity measures were self-reports of craving and mood. RESULTS: The alcohol prime had a robust effect on craving. Irrespective of the availability of the cue for consumption or the type of cue, craving was consistently higher when subjects were primed with alcohol than with placebo-alcohol. Negative mood was also higher when it was assessed after the alcohol prime. Negative mood decreased in alcohol-primed subjects when the alcohol cue was available for consumption. The alcohol cue also had a significant, although more modest effect on craving. The alcohol cue consistently elicited higher levels of craving relative to the water cue. CONCLUSIONS: These data suggest that the priming effects of alcohol may be a significant factor contributing to the experience of craving and maintenance of drinking. The study also introduces the cue-availability as an additional new method for investigating manipulations of cue-reactivity in alcoholics.

Adult↗

PubMed1993

Physical, subjective, and social availability: their relationship to alcohol consumption in rural and urban areas.

The alcohol availability literature indicates that under some conditions, physical availability is positively associated with per capita alcohol consumption. Smart (1980) suggested that at the individual level, subjective and social aspects of availability may mediate and outweigh the influence of physical availability. The study described here examined the simultaneous effects of physical, subjective, and social availability on alcohol consumption. Standardized telephone interviews were conducted with 781 adult drinkers. As hypothesized, physical availability was not a significant multivariate predictor of alcohol consumption for residents of high, medium, and low alcohol outlet density counties in Michigan (USA). Subjective and social availability indicators were significant predictors of alcohol consumption. Similar patterns of results were found in multiple regression analyses for blacks and whites and women and men, although blacks and women consumed less alcohol than did whites and men. The theoretical and practical implications of these results are discussed.

Adult↗

PubMed1995

Availability of rural Minnesota obstetric services: is it a problem?

In the late 1980s several published articles predicted a crisis in the availability of obstetric care due to declining numbers of rural obstetrical providers. Several state and national studies documented the adverse impact of malpractice and time demands on both urban and rural physicians. But only limited information is available to document current trends in rural obstetrical practice and assess whether or not the predicted crisis occurred. This study sought to provide that updated information for rural Minnesota. A telephone survey of all rural Minnesota obstetrical providers was used to document the number, location, and specialty of rural obstetrical providers, their practice limitations, and plans for future practice. This data was combined with state perinatal statistics for each county to further assess obstetrical care availability and perinatal outcomes. All rural Minnesota obstetricians and certified nurse midwives provide obstetrical care as did 69 percent of all rural family physicians. Only 27 percent of rural obstetrical providers put any type of restrictions on their obstetrical practices. During the past year, 67 currently practicing rural physicians have stopped providing obstetrical care while 55 new obstetrical providers have begun rural practice. Two to 3 percent of current rural providers plan to retire or discontinue obstetrical services during the next five years. The provider demographics from the survey identified eight counties with no prenatal providers, and 12 additional communities of decreased provider availability. However, only two of the counties with no prenatal providers and five of the counties with areas of limited providers had increased percentages of adverse prenatal outcomes such as low birthweight or late prenatal care. This study concluded that Minnesota does not have a serious statewide problem with availability of rural obstetrical providers. However, a few isolated regions of the state have limited provider availability, including limited availability of local high-risk services and consultants.

Catchment Area, Health↗

PubMed1997

Availability of iron to Pseudomonas fluorescens in rhizosphere and bulk soil evaluated with an ice nucleation reporter gene.

The biological availability of iron in the rhizosphere was assessed by evaluating ice nucleation activity (INA) expressed in situ by Pseudomonas fluorescens Pf-5 containing a transcriptional fusion (pvd-inaZ) of an iron-regulated promoter to an ice nucleation reporter gene (inaZ). Pf-5 containing pvd-inaZ expresses INA that is inversely related to the iron availability of a growth medium (J. E. Loper and S. E. Lindow, Appl. Environ. Microbiol. 60:1934-1941, 1994). INA expressed by rhizosphere populations of Pf-5 containing pvd-inaZ was at a maximum within 12 to 24 h following inoculation of the bacterium onto bean roots and typically decreased gradually during the following 4 days. Iron availability in the soil, which was altered by the addition of chelators, influenced INA expressed by rhizosphere populations of Pf-5 containing pvd-inaZ. In soil adjusted to a pH of 7.0 or 8.0 by adding Ca(OH)2, rhizosphere populations of Pf-5 containing pvd-inaZ expressed greater INA, indicating lower iron availability, than they did in the nonamended soil at a pH of 5.4. Similarly, rhizosphere populations of Pf-5 containing pvd-inaZ expressed less INA in an agricultural soil of pH 5.4 than in other agricultural soils ranging in pH from 6.4 to 7.7. These results conform to the predictions of chemical models stating that pH is a major factor influencing iron availability in soil solutions. The results of this study indicate that P. fluorescens Pf-5 encountered an iron-limited environment immediately after it was inoculated onto bean roots planted in agricultural field soils. One to two days after the bacterium was inoculated onto root surfaces, however, iron became more available to rhizosphere populations of Pf-5. We speculate that iron acquisition systems of plants and other rhizosphere organisms may provide available sources of iron to established rhizosphere populations of P. fluorescens.

Bacterial Outer Membrane Proteins↗

PubMed1999

Differential effects of pregnancy on mineralocorticoid and glucocorticoid receptor availability and immunoreactivity in cortisol feedback sites.

The suppression of plasma adrenocorticotropic hormone by very low levels of cortisol is reduced in pregnant adrenalectomized ewes, suggesting that pregnancy reduces the efficacy of the high-affinity corticosteroid receptor. This study was designed to determine the effects of pregnancy on the availability, immunoreactivity, and affinity of both corticosteroid receptors: the high-affinity mineralocorticoid receptor (MR) and the lower-affinity glucocorticoid receptor (GR). Availability was measured in the hypothalamus, pituitary, hippocampus and kidney using a saturation point radioligand binding assay. GR availability was significantly decreased in hippocampal cytosols obtained from pregnant ewes, but did not significantly change in other tissues. This finding is consistent with increased GR activation due to elevated circulating concentrations of cortisol. MR availability significantly increased from undetectable levels in hippocampal cytosols obtained from nonpregnant ewes to 2.8 +/- 1.6 fmol/mg protein in pregnant ewes, suggesting a reduced MR activation in the hippocampus during pregnancy. MR availability tended to be greater in other tissues during pregnancy, but these differences were not significant. The amount of immunoreactive MR (iMR) and GR (iGR) protein was estimated by quantifying Western blots. iGR significantly increased in the pituitary, but did not significantly change in other tissues. In contrast, iMR was significantly increased during pregnancy in all tissues assayed, suggesting that an increased cytosolic MR protein amount contributes to the observed increase in MR availability. Since studies suggest that progesterone is a potent anticorticosteroid, we tested for evidence of endogenous inhibition of binding to MR and/or GR during pregnancy by determining MR and GR affinity in pituitary cytosols obtained from nonpregnant and pregnant ewes. Although there was a tendency towards a decreased affinity of the MR in pregnant ewes, there was no significant change in the K(D) of the pituitary MR or GR during pregnancy. We hypothesize that an alteration in activation and/or autoregulation of the MR during pregnancy, particularly in the hippocampus, may contribute to the observed changes in receptor availability and immunoreactivity and increase basal plasma cortisol levels during pregnancy.

Animals↗

PubMed1984

Maximal upstroke velocity as an index of available sodium conductance. Comparison of maximal upstroke velocity and voltage clamp measurements of sodium current in rabbit Purkinje fibers.

We compared the maximal upstroke velocity of action potentials in short rabbit Purkinje fibers with sodium currents measured with a two-microelectrode voltage clamp. The number of sodium channels available to open during a sudden depolarization was varied either by blockade with tetrodotoxin or by inactivation with steady depolarizations. In both cases, the maximal upstroke velocity was found to be a very nonlinear measure of the number of available sodium channels. For example, 3 microM tetrodotoxin blocks 85% of the sodium channels, but reduces the maximal upstroke velocity by only 33%. Voltage clamp and upstroke velocity experiments were reconstructed with a computer model of the rabbit Purkinje fiber preparation that was closely based on experimental measurements of passive cable properties and sodium channel characteristics. The simulations indicate that our voltage clamp measurements of sodium current accurately report changes in channel availability, but they also show that the maximal upstroke velocity is a strongly nonlinear index of available sodium conductance. Most of the nonlinearity arises from the activation kinetics of the sodium channels: as the pool of available channels decreases, a greater percentage of those channels activate and contribute inward current at the time of the maximal upstroke velocity. Simulations predict that the maximal upstroke velocity-available sodium conductance relationship would still remain nonlinear at 37 degrees C or under different stimulus conditions that give uniform or continuously propagated action potentials. The nonlinearity may invalidate inferences based on earlier maximal upstroke velocity experiments: the existence of two types of sodium channels with different tetrodotoxin sensitivity, steady state voltage dependence of tetrodotoxin block, voltage range over which sodium channels inactivate, and rapid, then slow recovery of sodium channel availability following a sudden repolarization. All of these conclusions need to be reevaluated.

Action Potentials↗

PubMed1984

Changes in available gonadotropin receptors in the corpus luteum of the rhesus monkey during simulated early pregnancy.

Stimulation of the primate corpus luteum (CL) by endogenous CG in early pregnancy or by exogenous human CG (hCG) in simulated early pregnancy, is transient, despite continued exposure to rising concentrations of CG. The objective of this study was to determine if the transitory response of the CL to CG is related to changes in gonadotropin receptors. Numbers and affinities of available LH/CG binding sites were characterized in the CL of rhesus monkeys (n = 27) during prolonged CG exposure in simulated early pregnancy, and the temporal relationship between changes in receptor parameters and in luteal function was examined. Administration of hCG increased progesterone concentrations above pretreatment levels within 9 h (2.2 +/- 0.8 vs. 7.6 +/- 1.1 ng/ml, mean +/- SE, P less than 0.05); the relative increase (345% of control) in serum progesterone was more profound than that of available hCG binding sites (135%, P greater than 0.05) or luteal weight (128%, P greater than 0.05) over this interval. Receptor affinities for hCG remained comparable to pretreatment values (Kd = 1.1 +/- 0.2 X 10(-10) M) throughout this 9-h period. A significant diminution in available hCG receptors occurred between 9 h (12.7 +/- 2.1 fmol/mg tissue) and 3 days (7.4 +/- 1.5 fmol/mg tissue) of hCG treatment (P less than 0.05). The loss of available CG receptors preceded a significant decline in serum progesterone concentrations. Serum progesterone decreased by 6 days (4.0 +/- 0.6 ng/ml, P less than 0.05) of hCG treatment, as did receptor affinity for hCG (Kd = 4.7 +/- 0.9 X 10(-10) M, P less than 0.05). Numbers and affinities of available receptors for hCG and serum progesterone concentrations fell before any decrease in luteal weight. Binding capacities and receptor affinities for human LH were comparable to those for hCG throughout simulated early pregnancy. In conclusion, the population of available LH/CG receptors in the macaque CL is maintained, or perhaps modestly increased, amidst dramatic stimulation of luteal function during early CG exposure. The subsequent diminution of number and affinity of available LH/CG receptors during prolonged exposure to CG in early pregnancy may compromise CL function and thus participate in the establishment of the transient nature of the luteal response to CG.

Animals↗

PubMed2003

Luteinizing hormone pulsatility is disrupted at a threshold of energy availability in regularly menstruating women.

To investigate the dependence of LH pulsatility on energy availability (dietary energy intake minus exercise energy expenditure), we measured LH pulsatility after manipulating the energy availability of 29 regularly menstruating, habitually sedentary, young women of normal body composition for 5 d in the early follicular phase. Subjects expended 15 kcal/kg of lean body mass (LBM) per day in supervised exercise at 70% of aerobic capacity while consuming a clinical dietary product to set energy availability at 45 and either 10, 20, or 30 kcal/kg LBM.d in two randomized trials separated by at least 2 months. Blood was sampled daily during treatments and at 10-min intervals for the next 24 h. Samples were assayed for LH, FSH, estradiol (E2), glucose, beta-hydroxybutyrate, insulin, cortisol, GH, IGF-I, IGF-I binding protein (IGFBP)-1, IGFBP-3, leptin, and T3. LH pulsatility was unaffected by an energy availability of 30 kcal/kg LBM.d (P > 0.3), but below this threshold LH pulse frequency decreased, whereas LH pulse amplitude increased (all P < 0.04). This disruption was more extreme in women with short luteal phases (P < 0.01). These incremental effects most closely resembled the effects of energy availability on plasma glucose, beta-hydroxybutyrate, GH, and cortisol and contrasted with the dependencies displayed by the other metabolic hormones (simultaneously P < 0.05). These results demonstrate that LH pulsatility is disrupted only below a threshold of energy availability deep into negative energy balance and suggest priorities for future investigations into the mechanism that mediates the nonlinear dependence of LH pulsatility on energy availability.

Adult↗

PubMed1999

Alcohol availability and workplace drinking: mixed method analyses.

OBJECTIVE: This article investigates the relationship between subjective social and physical availability of alcohol at work and work-related drinking. METHOD: We integrated survey and ethnographic methods to determine if and why physical and social availability of alcohol predicted work-related drinking in a manufacturing plant with approximately 6,000 employees. Survey data were obtained from in-home interviews with 984 randomly selected workers. Respondents were asked about their overall and work-related drinking, their perceptions of the ease of obtaining or consuming alcohol in the plant, the work-related drinking of others and their approval/disapproval of work-related drinking by co-workers. Ethnographic data were obtained from 3 years of periodic onsite observations and semistructured interviews with key informants to investigate factors underlying alcohol availability and drinking at work. RESULTS: Structural equations modeling of the survey data revealed that subjective social availability of alcohol at work, and particularly perceived drinking by friends and co-workers, was the strongest predictor of work-related drinking. Typical frequency and quantity of alcohol consumption and heavy drinking were predictive also. Subjective physical availability of alcohol was not significantly related to drinking at or before work. Findings from the ethnographic analyses explained survey findings and described characteristics of the work culture that served to encourage and support alcohol availability and drinking. CONCLUSIONS: These results are the first to show significant relationships between alcohol availability and drinking at work, to explain dynamics of that relationship and to demonstrate the potential risks of using only quantitative or only qualitative findings as the basis for prevention.

Alcohol Drinking↗

PubMed1981

Alcohol availability and cirrhosis mortality rates by gender and race.

This study test whether the availability of alcoholic beverages is a simple integrated dimension as implied by certain policy models and in its treatment by researchers. Factor analysis reveals two independent availability factors: on-premise and retail availability. A correlation analysis found that on-premise availability was related to cirrhosis mortality rates for the total population, White males, non-White males, and White females. It was not related to non-White female cirrhosis mortality. In contrast, retail availability was not related to any of cirrhosis mortality rates. Examination of the states with extremes of high and low on-premise availability indicates that this type of availability is not a manipulable control variable but an index of extant norms toward drinking. It is recommended that differential prevention strategies be adopted rather than a uniform policy prevention model.

Alcoholic Beverages↗