Accuracy of predicting chemical body composition of growing pigs using dual-energy X-ray absorptiometry.

Studies in animal science assessing nutrient and energy efficiency or determining nutrient requirements benefit from gathering exact measurements of body composition or body nutrient contents. Those are acquired by standardized dissection or by grinding the body followed by wet chemical analysis, respectively. The two methods do not result in the same type of information, but both are destructive. Harnessing human medical imaging techniques for animal science can enable repeated measurements of individuals over time and reduce the number of individuals required for research. Among imaging techniques, dual-energy X-ray absorptiometry (DXA) is particularly promising. However, the measurements obtained with DXA do not perfectly match dissections or chemical analyses, requiring the adjustment of the DXA via calibration equations. Several calibration regressions have been published, but comparative studies of those regression equations and whether they are applicable to different data sets are pending. Thus, it is currently not clear whether existing regression equations can be directly used to convert DXA measurements into chemical values or whether each individual DXA device will require its own calibration. Our study builds prediction equations that relate body composition to the content of single nutrients in growing entire male pigs (BW range 20-100 kg) as determined by both DXA and chemical analyses, with R2 ranging between 0.89 for ash and 0.99 for water and CP. Moreover, we show that the chemical composition of the empty body can be satisfactorily determined by DXA scans of carcasses, with the prediction error ranging between 4.3% for CP and 12.6% for ash. Finally, we compare existing prediction equations for pigs of a similar range of BWs with the equations derived from our DXA measurements and evaluate their fit with our chemical analysis data. We found that existing equations for absolute contents that were built using the same DXA beam technology predicted our data more precisely than equations based on different technologies and percentages of fat and lean mass. This indicates that the creation of generic regression equations that yield reliable estimates of body composition in pigs of different growth stages, sexes and genetic breeds could be achievable in the near future. DXA may be a promising tool for high-throughput phenotyping for genetic studies, because it efficiently measures body composition in a large number and wide array of animals.

Effects of dietary CP and amino acid restriction on the growth dynamics of organs and body components in entire male, castrated and female pigs.

The optimized use of dietary nutrients and the accurate knowledge of the growth dynamics of body components is important for efficient pig production. This study aimed at evaluating the growth of carcass components and organs of Swiss Large White pigs from birth to 140 kg BW depending on the CP and amino acid (AA) supply. A total of 66 entire males (EM), 58 castrates (CA) and 66 female (FE) pigs were used. From 20 kg BW onwards, they had either ad libitum access to a control (C) or a diet (LP) with 20% lower CP, lysine, methionine + cystine, threonine and tryptophan content compared to C. The weight of organs, primal cuts and external fat were recorded in eight EM and eight FE; at 10 kg BW, on two EM, CA and FE each, and at 20 kg BW, on eight pigs from each sex. From 40 to 140 kg BW at 20 kg intervals, measurements were recorded on four pigs per sex and dietary treatment. The weight of each component was related to empty body (EB) using allometric regressions. Kidneys were heavier (P<0.05) in C- than LP-pigs and in EM than CA and FE. Above 21 kg EB weight, growth rate of LP-FE overpassed (P<0.05) the one of C-pigs. Consequently, LP-FE had heavier (P<0.05) lean cuts than C-pigs in the finisher period. However, LP-CA and LP-EM displayed lower (P<0.05) weights and growth rates of the lean cuts than C-CA and C-EM. Shoulder and loin weights and growth rates were reduced (P<0.05) in LP-pigs when compared to C-pigs. Growth rates of the ham were greater (P<0.05) in LP-FE than C-FE, whereas in LP-EM and LP-CA they were lower (P<0.05) than their C-counterparts. Total amounts of subcutaneous fat, backfat, ham fat and shoulder fat were lower (P<0.05) in C- than LP-pigs. The total amount of subcutaneous fat, backfat and shoulder fat of C-CA was, regardless of diet, greater (P<0.05) than of C-FE. In the LP group, this difference was even more pronounced. The amount of deposited ham fat was greater (P<0.05) in LP-CA than LP-FE, but not in C-CA v. C-FE. Differences in kidney weights suggested a greater nitrogen clearance required in C-pigs. Overall, dietary restriction and sex did not affect all body parts to the same extent. This study further suggests the possibility to reduce the CP and AA supply in FE without compromising the yield of primal lean cuts or increasing the amount of subcutaneous fat.

Dietary CP and amino acid restriction has a different impact on the dynamics of protein, amino acid and fat deposition in entire male, castrated and female pigs.

Breeding efforts over the last decades altered markedly empty body (EB) composition of pigs. This study aimed to re-evaluate the dynamics of changes in the composition and deposition rate of fat, protein and amino acids (AA) in the EB from birth to 140 kg BW depending on the dietary CP and AA supply in a current pig genotype. In the experiment 66 entire male, 58 castrated and 66 female Swiss Large White pigs were used. From 20 kg BW onwards, they had either ad libitum access to a control (C) diet or a diet (LP) compared to diet C only 80% of CP, lysine, methione+cystine, threonine and tryptophan. The EB composition was determined at birth on eight boars and eight females, at 10 and 20 kg BW on two boars, two castrates and two females, and at 20 kg intervals from 40 to 140 kg BW, on four pigs per gender and dietary treatment. Each EB fraction was weighed and analysed for protein, fat and AA profile. The AA-to-lysine ratio was calculated and the different chemical component contents were fitted to allometric regressions. Overall, C-boars had the greatest EB protein and AA content and deposition rates, and lowest fat content and deposition rates. At the beginning of the grower period, LP-castrates and females displayed the lowest protein and AA and the highest fat deposition rates. However, compared with their counterparts in the C-group, in LP-castrates and females protein and AA deposition rates were greater above 64 and 40 kg EB weight, respectively, whereas fat deposition rates was lower above 80 kg EB weight. Thus, there seems a great potential to optimise protein and AA efficiency especially in the finisher period in castrates and females. Important individual variations were found in the essential AA-to-lysine ratio of the EB. Phenylalanine and threonine-to-lysine ratios decreased with increasing EB weight. Valine- and threonine-to-lysine ratios in C-castrates and C-females were 5% and 4% greater than recently reported by the National Research Council (NRC) whereas cysteine-, methionine- and tyrosine-to-lysine ratios were lower by 34%, 25% and 10%, respectively. The clear differences found between the EB AA-to-lysine ratios in the present study and the NRC might partly be explained by the genotype and the temporal changes in the relative weight of each EB fraction or changes in the AA profile. Nevertheless, these findings on changes in the essential AA profile of tissue protein warrant further studies.

Dynamics of the mineral composition and deposition rates in the empty body of entire males, castrates and female pigs.

Mineral composition and relative deposition rates in the pig's body are used to assess the mineral net requirements for growth and input-output balances. The study aimed to examine the dynamics of changes in mineral composition and deposition rates in the empty body (EB) from birth to 140 kg BW depending on dietary protein supply. In the experiment, 66 entire male, 58 castrated and 66 female Swiss Large White pigs were used to determine body composition at birth, 10, 20 kg and at 20 kg intervals from 40 to 140 kg BW. From 20 kg BW, they had either ad libitum access to a control grower and finisher diet or a grower and finisher diet containing 80% CP, lysine, methione+cystine, threonine and tryptophan of the control diet. Each EB fraction (carcass, organs and empty intestines, blood and bile) was weighed and analyzed for water, ash, calcium, phosphorous, magnesium, potassium, sodium, copper, iron, manganese and zinc contents. Allometric relationships between the amount of each mineral in the EB and the EB weight (EBW) were fitted. The R2 of the allometric equations was above 0.92, except for copper and manganese (below 0.33), revealing the EBW as an excellent explanatory variable of the analyzed amounts. The copper and manganese composition in the EB were extremely low and variable which explain the low R2. Except for zinc, all mineral relative deposition rates decreased with increasing EBW. The amount of ash, calcium and phosphorus in the EB was not affected by the diet, but when expressed relative to body protein these minerals were increased when pigs were fed the low protein diet. This suggests an independent protein deposition and bone mineralization when animals are fed diets limiting in protein content. The diet also affected the amount of potassium in the EB which was greater when the low protein diet was fed. The gender only affected the amounts of potassium and sodium in the EB which were greater in entire males. Entire males had also greater amounts of water in the EB, which may explain the observed effect of gender on these two electrolytes. Finally, gender and dietary protein did not affect to a sufficient relevant way the body mineral composition and deposition rates in the EB, suggesting that their distinction may not be necessary to assess, on BW basis, the mineral net requirements for growth and the exported amount of minerals in input-output balances.

Long-term effects of castration, chronic intermittent social stress, provision of grass silage and their interactions on performance and meat and adipose tissue properties in growing-finishing pigs.

In order to assess chronic stress in entire and castrated male pigs and to describe effects of a provision of grass silage in those pigs, a 2 × 2 × 2 factorial experiment comprising the factors castration, chronic intermittent social stress and provision of grass silage was carried out with 147 growing-finishing pigs from 25.6 to 102.1 kg body weight. The experimental design allowed investigating interactions between the three factors, but only few were statistically significant. Stress exposure consisted of repeated short-term confrontations with unfamiliar pigs and short-term separations. Carcasses of stress-exposed pigs had thicker backfat, lower lean meat percentage and a different fatty acids composition of the adipose tissue. While entire males differed strongly from castrates in performance, carcass characteristics and adipose tissue properties, we found no evidence for an increased level of chronic stress in entire males compared to castrates. Provision of grass silage increased stomach weight and reduced dressing percentage, but did not impair performance, adipose tissue properties or meat quality.

Impact of amino acid and CP restriction from 20 to 140 kg BW on performance and dynamics in empty body protein and lipid deposition of entire male, castrated and female pigs.

Breeding leaner pigs during the last decades may have changed pig's empty body (EB) composition, a key trait for elaborating feeding recommendations. This research aimed to provide new experimental data on changes in the chemical composition of the EB of pigs from 20 to 140 kg BW. In addition, the impact of a reduction in the dietary CP associated with lower lysine, methionine+cystine, threonine and tryptophan levels was determined. In total, 48 males, castrates and females weighing 20 kg BW were allocated either to a control grower-finisher diet formulated according to current Swiss feeding recommendations, or a low CP grower-finisher diet (80% of control). Feed intake was monitored and pigs were weighed weekly. The chemical composition of EB (blood, hairs and hoofs, offals, bile, carcass) was determined at 20, 40, 60, 80, 100, 120 and 140 kg BW on four pigs per gender and diet (eight pigs per gender at 20 kg). The five fractions were weighed and samples were analysed for dry matter, protein, fat and energy. Nutrient deposition rates and N efficiency were calculated by using the 20 kg BW category as reference. Analysis revealed an accurate feed optimisation for the aforementioned essential amino acids (EAA), whereas digestible isoleucine content in the low CP diet was at 70% of the control diet. Despite similar feed intake, daily gain and feed efficiency were impaired (P<0.01) from 20 to 100 kg BW in the low CP compared with the control pigs. In the same growth period, castrates had the greatest feed intake but, together with females, displayed the lowest (P<0.01) feed efficiency. Protein deposition was reduced (P<0.01) by up to 31% with low CP diet and was lower (P<0.01) in castrates and females than males at 100 kg BW. The greatest fat deposition rates were found with low CP diet and castrates. N efficiency improved (P<0.05) by 10% with the low CP diet from 100 to 140 kg. The males displayed the greatest (P<0.05) N efficiency. These findings suggest that the CP content of finisher II diets could be reduced to 102, 102 and 104 g/kg for females, castrates and males, respectively, without a negative impact on protein deposition or growth. It remains unclear whether the negative effects found in the BW range from 20 to 100 kg on the EB deposition were due to the 20% reduction of the dietary CP and the five limiting EAA or to other EAA via an unbalanced EAA profile.

The dendritic cell high-affinity IgE receptor is overexpressed in both asthma and severe COPD.

BACKGROUND: The reduction of asthma exacerbations following omalizumab treatment has been related to the suppression of the high-affinity IgE receptor (FcεRI) on plasmacytoid dendritic cells (DCs). However, the FcεRI expression on DCs in chronic obstructive pulmonary disease (COPD) is unknown. OBJECTIVE: To compare FcεRI expression on DCs in COPD with patients with allergic asthma and healthy controls, and to relate the findings to clinical parameters, blood eosinophil concentrations and serum immunoglobin E (IgE) concentrations. METHODS: Using four-colour flow cytometry, FcεRI expression on blood myeloid DCs and plasmacytoid DCs was analyzed in 64 patients with COPD, 20 patients with allergic asthma, 41 asymptomatic never smokers and 21 asymptomatic current smokers. RESULTS: As compared with never smokers, current smokers displayed an increased expression of the FcεRI on myeloid and plasmacytoid DCs. In patients with COPD, the expression of the FcεRI on plasmacytoid DCs, but not myeloid DCs, increased from spirometric GOLD stage 2 to GOLD stage 4, and was correlated with several lung function parameters. Patients with severe COPD and patients with allergic asthma displayed a similar FcεRI overexpression on plasmacytoid DCs. In all groups, there was a positive correlation between total IgE serum concentrations and the FcεRI expression on plasmacytoid DCs. CONCLUSIONS AND CLINICAL RELEVANCE: Severe COPD and allergic asthma are characterized by a similar overexpression of the high-affinity IgE receptor on plasmacytoid DCs. In view of the effect of anti-IgE on exacerbations in asthma, trials investigating the effect of anti-IgE on exacerbations in severe COPD appear to be warranted.

Effects of benzoic Acid and dietary calcium:phosphorus ratio on performance and mineral metabolism of weanling pigs.

In a 2×2 factorial experiment the hypotheses tested were that the metabolic acid load caused by benzoic acid (BA) added to the feed affects bone mineralization of weanling pigs, and that a wide dietary calcium (Ca) to phosphorus (P) ratio in phytase-supplemented feeds with a marginal P concentration has a positive effect on bone mineralization. The four experimental diets, which contained 0.4% P and were supplemented with 1,000 FTU phytase/kg, contained either 5 g BA/kg or no BA and either 0.77% Ca or 0.57% Ca. The 68 four-week-old Large White pigs were fed the experimental diets ad libitum for six weeks and were then slaughtered. Benzoic acid increased feed intake (p = 0.009) and growth rate (p = 0.051), but did not influence the feed conversion ratio (p>0.10). Benzoic acid decreased the pH of the urine (p = 0.031), but did not affect breaking strength and mineralization of the tibia (p>0.10). The wide Ca:P ratio decreased feed intake (p = 0.034) and growth rate (p = 0.007) and impaired feed the conversion ratio (p = 0.027), but increased the mineral concentration in the fat-free DM of the tibia (p = 0.013) without influencing its breaking strength (p>0.10). The observed positive effect of the wide Ca:P ratio on bone mineralization may be attributed, at least in part, to the impaired feed conversion ratio, i.e. to the higher feed intake and consequently to the higher mineral intake per kg BW gain. The negative impact on animal performance of the wide dietary Ca:P ratio outweighs its potentially positive effect on bone mineralization, precluding its implementation under practical feeding conditions.

Ferromagnetic coupling of mononuclear Fe centers in a self-assembled metal-organic network on Au(111).

The magnetic state and magnetic coupling of individual atoms in nanoscale structures relies on a delicate balance between different interactions with the atomic-scale surroundings. Using scanning tunneling microscopy, we resolve the self-assembled formation of highly ordered bilayer structures of Fe atoms and organic linker molecules (T4PT) when deposited on a Au(111) surface. The Fe atoms are encaged in a three-dimensional coordination motif by three T4PT molecules in the surface plane and an additional T4PT unit on top. Within this crystal field, the Fe atoms retain a magnetic ground state with easy-axis anisotropy, as evidenced by x-ray absorption spectroscopy and x-ray magnetic circular dichroism. The magnetization curves reveal the existence of ferromagnetic coupling between the Fe centers.

Acute effects of tobacco smoke on human airway dendritic cells in vivo.

Airway dendritic cells (DCs) play a key role in smoke-related lung diseases; however, the acute effects of tobacco smoke on human airway DCs in vivo are unknown. A total of 16 smokers underwent bronchoalveolar lavage at two time-points: directly after a 4-h period of nonsmoking (no smoke exposure); and directly after a 4-h period during which eight cigarettes were smoked (acute smoke exposure). Using flow cytometry, myeloid DCs (mDCs) and plasmacytoid DCs (pDCs), as well as function-associated surface molecules on mDCs, were analysed in bronchoalveolar lavage fluid (BALF) and in blood. The numbers of macrophages, lymphocytes, neutrophils, eosinophils and pDCs were unchanged in BALF following acute smoke exposure, as compared to no smoke exposure. In contrast, there was a strong increase in mDC number in BALF and a concomitant decrease in mDC number in blood following acute smoke exposure. In addition, acute smoke exposure led to an increase in the expression of the surface molecules blood dendritic cell antigen 1 and 4 and a decrease in the expression of the lung homing receptor, CC chemokine receptor 5, on mDCs in BALF. Acute tobacco smoke inhalation results in an immediate and selective recruitment of mDCs into human airways, which might reflect the very early reaction of the adaptive immune system to smoke exposure.

Compliance with a critical pathway for the management of febrile neutropenia and impact on clinical outcomes.

Febrile neutropenia is associated with significant morbidity and mortality. Managing infectious in neutropenic patients remains a dynamic process, making necessary timely and efficient empirical antibiotic therapy. The implementation of critical pathways has been suggested as a strategy to improve clinical effectiveness. This study evaluated the compliance with an institutional critical pathway for the management of febrile neutropenia and the impact on clinical outcomes at Hospital de Clínicas de Porto Alegre, Brazil (HCPA). We performed a cohort study that prospectively included patients hospitalized from January 2004 to December 2005 and presented febrile neutropenia (190 episodes). Historical controls were selected from March 2001 to April 2003 (193 episodes) before the critical pathway was introduced. This study showed a low rate of full compliance (21.6%; 95% CI 15.7-27.5) with the critical pathway. In most cases, there was partial compliance (67.9%; 95% CI 61.3-74.5). Despite the moderate adherence observed, we recorded a decrease in in-hospital all-cause mortality in the sample studied after protocol implementation (from 24.4 to 14.4%; P = 0.017) and reduction in the length of use of cephalosporin and quinolones. In conclusion, implementation of a critical pathway seems to be an effective strategy to improve clinical outcomes in patients hospitalized with febrile neutropenia.

Effects of Fusarium toxins on growth, humoral immune response and internal organs in weaner pigs, and the efficacy of apple pomace as an antidote.

A feeding trial using 220 weaner pigs which comprised two experimental series was conducted to investigate the effects of diets contaminated with the Fusarium toxins deoxynivalenol (DON) and zearalenone (ZON) and to test the hypothesis that apple pomace acts as an antidote to these mycotoxins. Two diets without contaminated wheat, containing either no pomace or 8% pomace, and two diets with naturally contaminated wheat (3.2 mg DON and 0.06 mg ZON, and 2.1 mg DON and 0.25 mg ZON per kg diet in series 1 and 2 respectively), containing either no pomace or 8% pomace were fed ad libitum for 5 weeks. Mycotoxin exposure lowered feed intake (p < 0.01) and growth (p = 0.05), and tended to decrease the energy conversion ratio (p = 0.06). Although the intake of apple pomace did not increase feed intake, it increased the growth rate (p = 0.04), mainly by restoring growth in the presence of mycotoxins (p = 0.08 for the interaction mycotoxin x pomace). In the first experimental series, the animals were immunized with a parvovirus vaccine. The percentage of seroconverting animals did not differ between the treatments (p = 0.56), which indicates that DON did not affect the humoral immune response. In the second experimental series, female piglets fed the contaminated diets had heavier uteri than piglets fed the uncontaminated diets (p < 0.01), regardless of pomace supplementation. The results show that pomace may alleviate the negative effect of DON on growth but does not counteract the hormonal effects of ZON.

Regulation of brain-derived neurotrophic factor (BDNF) during sleep apnoea treatment.

BACKGROUND: Patients with obstructive sleep apnoea syndrome (OSAS) often display persistent cognitive dysfunction despite effective treatment with continuous positive airway pressure (CPAP). Brain-derived neurotrophic factor (BDNF) is a key mediator of memory and cognition, but its regulation in OSAS and during CPAP treatment is unknown. METHODS: Serum and plasma BDNF concentrations, BDNF secretion by peripheral blood mononuclear cells, and overnight polysomnography were evaluated in 17 men with newly diagnosed OSAS (as defined by a respiratory disturbance index of >10/hour with >70% obstructive events and corresponding daytime symptoms) and 12 healthy control men. In the patients all the parameters were monitored after 1 night and 3 months of CPAP treatment. RESULTS: There was no significant difference in baseline serum BDNF, plasma BDNF, or spontaneous BDNF secretion by peripheral blood mononuclear cells between untreated patients and controls. After 1 night of CPAP treatment there was a steep fall in median serum BDNF (from 18.0 ng/ml to 4.1 ng/ml) and plasma BDNF (from 58.7 pg/ml to 22.0 pg/ml) concentrations. Following 3 months of treatment BDNF concentrations did not return to baseline. In contrast, BDNF secretion was not suppressed by CPAP treatment. CONCLUSIONS: Patients with untreated OSAS have normal serum and plasma BDNF levels. CPAP treatment is associated with a rapid decrease in serum and plasma BDNF levels which may reflect enhanced neuronal demand for BDNF in this condition.

Hypercortisolemia decreases dexamethasone half-life in rabbit.

The pharmacokinetics of dexamethasone have been found to be related to endogenous hypothalamic-pituitary-adrenal (HPA) axis activity. Lower plasma dexamethasone levels in psychiatric patients (especially depressed) who are dexamethasone suppression test (DST) nonsuppressors have previously been reported. Since DST nonsuppression is one measure of HPA axis hyperactivity and is usually associated with relatively increased plasma cortisol levels and lower post dose plasma dexamethasone levels, we hypothesized that hypercortisolemia can induce a more rapid disappearance of dexamethasone from plasma. We therefore studied the kinetics of dexamethasone in rabbits before and after a period of sustained hypercortisolemia produced by administration of IM hydrocortisone acetate, a slowly absorbed salt of cortisol. Mean dexamethasone half-life decreased significantly from baseline of 1.92 h on day zero in seven rabbits to 1.17 h on experimental day 17 of induced hypercortisolemia (P < 0.001), while there was no significant change in saline treated controls (n = 3). Dexamethasone half-life had returned to the baseline levels when retested 88 days later on experimental day 105. The results indicate that pronounced hypercortisolemia decreases dexamethasone half-life in rabbits, and support the concept that increased circulating cortisol levels induce hepatic enzymes that metabolize dexamethasone. Thus, the lower postdexamethasone plasma dexamethasone levels and decreased dexamethasone half-life in DST nonsuppressors may in part reflect the effect of prior or coincident hypercortisolemia.

Fatigue, serum cytokine levels, and blood cell counts during radiotherapy of patients with breast cancer.

PURPOSE: To assess the level of fatigue during the course of adjuvant radiotherapy (RT) of breast cancer patients and its relation to anxiety, depression, serum cytokines, and blood count levels. METHODS AND MATERIALS: Forty-one patients who received adjuvant RT after breast-conserving surgery were prospectively studied. All patients underwent RT without concomitant chemotherapy. Patients rated their fatigue with two standardized self-assessment instruments, the Fatigue Assessment Questionnaire and a visual analog scale on fatigue intensity, before RT, during weeks 1-5 of RT, and 2 months after RT completion. In addition, the anxiety and depression levels were assessed with the Hospital Anxiety and Depression Scale. A differential blood cell count and the serum levels of the cytokines interleukin (IL)-1beta, IL-6, and tumor necrosis factor-alpha were determined in parallel to the fatigue assessments. RESULTS: Fatigue intensity as assessed with the visual analog scale increased (p <0.001) until treatment week 4 and remained elevated until week 5. Two months after RT, the values had fallen to the pretreatment levels. Fatigue measured with the Fatigue Assessment Questionnaire did not increase significantly during treatment, but the subscores on physical (p = 0.035) and cognitive (p = 0.015) fatigue were elevated during treatment weeks 4 and 5. Affective fatigue did not change significantly. Anxiety, as rated with the Hospital Anxiety and Depression Scale, declined during RT (p = 0.002), but the Hospital Anxiety and Depression Scale depression score did not change significantly. IL-1beta, IL-6, and tumor necrosis factor-alpha levels did not change during therapy and did not correlate with fatigue. Peripheral blood cell levels declined significantly during therapy and were still low 2 months after treatment. Until treatment week 5, lymphocytes were reduced to almost 50% of their initial values. Hemoglobin levels did not correlate with fatigue. CONCLUSIONS: We observed an increase in fatigue during adjuvant RT of patients with breast cancer. Fatigue returned to pretreatment levels 2 months after treatment. No evidence was found that anxiety, depression, serum levels of IL-1beta, IL-6, tumor necrosis factor-alpha, or declining hemoglobin levels were responsible for the treatment-induced fatigue.

Lithium isotopes: differential effects on renal function and histology.

OBJECTIVES: Reduction in renal concentrating ability has been reported in patients undergoing chronic lithium treatment. Prior work has demonstrated differences in physiological effects of the stable lithium isotopes, 6Li and 7Li. Here, we measured the degree of polyuria, polydipsia and kidney histological changes induced in rats by equimolar amounts of 6LiCl, 7LiCl and the commercially available mixture of both isotopes. METHODS: Rats were given 1.0 mEq/kg of either 6LiCl, 7LiCl or 'nLiCl' (isotope mixture, 93% 7LiCl) by subcutaneous injection twice daily for up to 49 days. Twenty-four-hour urine volume and water intake were measured daily. Kidneys from rats treated for 7 days with 1.5 mEq/kg 6LiCl, 7LiCl and vehicle were examined under light microscopy and histopathologic changes graded on a 4-point scale of severity. RESULTS: All rats showed loss in renal concentrating ability manifested by increasing urine volume and water intake. Peak effects occurred after 9-13 days treatment, then declined to stable levels at two to three times pre-treatment level. Mean peak effect was significantly greater for 6LiCl than for 7LiCl. Chronic effects of 6LiCl (weeks 3-7 of treatment) on polyuria and polydipsia were persistently higher than that of 7LiCl. nLiCl effect was intermediate. Kidneys from rats treated for 7 days with 6LiCl showed more frequently severe lesions in renal tubules than did 7LiCl-treated rats. CONCLUSIONS: Our current data and prior studies suggest that elimination or reduction of 6Li from pharmaceutical preparations may merit further evaluation as a possibly less potentially nephrotoxic form of lithium treatment.

Anal duct carcinoma: report of case and a survey of the experience of the American Osteopathic College of Proctology.

Anal duct carcinoma, also known as anal gland carcinoma or adenocarcinoma of the anal canal, is an unusual anal cancer that accounts for approximately 0.1% of all gastrointestinal cancers. Delays in diagnosis most likely account for the poor prognosis associated with this cancer. Presenting symptoms often mimic those of more common benign anorectal pathologic processes. Multimodality treatment that includes surgery, chemotherapy, and radiation therapy is often recommended. The authors describe a typical case of anal duct carcinoma and its management. They also discuss the findings of a survey of the combined experience of members of the American Osteopathic College of Proctology and review the literature.

The effects of density, spatial pattern, and competitive symmetry on size variation in simulated plant populations.

Patterns of size inequality in crowded plant populations are often taken to be indicative of the degree of size asymmetry of competition, but recent research suggests that some of the patterns attributed to size-asymmetric competition could be due to spatial structure. To investigate the theoretical relationships between plant density, spatial pattern, and competitive size asymmetry in determining size variation in crowded plant populations, we developed a spatially explicit, individual-based plant competition model based on overlapping zones of influence. The zone of influence of each plant is modeled as a circle, growing in two dimensions, and is allometrically related to plant biomass. The area of the circle represents resources potentially available to the plant, and plants compete for resources in areas in which they overlap. The size asymmetry of competition is reflected in the rules for dividing up the overlapping areas. Theoretical plant populations were grown in random and in perfectly uniform spatial patterns at four densities under size-asymmetric and size-symmetric competition. Both spatial pattern and size asymmetry contributed to size variation, but their relative importance varied greatly over density and over time. Early in stand development, spatial pattern was more important than the symmetry of competition in determining the degree of size variation within the population, but after plants grew and competition intensified, the size asymmetry of competition became a much more important source of size variation. Size variability was slightly higher at higher densities when competition was symmetric and plants were distributed nonuniformly in space. In a uniform spatial pattern, size variation increased with density only when competition was size asymmetric. Our results suggest that when competition is size asymmetric and intense, it will be more important in generating size variation than is local variation in density. Our results and the available data are consistent with the hypothesis that high levels of size inequality commonly observed within crowded plant populations are largely due to size-asymmetric competition, not to variation in local density.

The L-gulono-gamma-lactone oxidase gene (GULO) which is a candidate for vitamin C deficiency in pigs maps to chromosome 14.

Vitamin C deficient pigs, when fed a diet lacking L-ascorbic acid (AscA), manifest deformity of the legs, multiple fractures, osteoporosis, growth retardation and haemorrhagic tendencies. This trait was shown by others to be controlled by a single autosomal recessive allele designated as od (osteogenic disorder). The inability of AscA biosynthesis in primates and guinea pigs that exhibit similar symptoms, when they are not supplemented with AscA in the food, was traced to the lack of L-gulono-gamma-lactone oxidase, which catalyzes the terminal step in the biosynthesis of AscA. The non-functional GULOP was mapped to human chromosome 8p21 that corresponds to an evolutionarily conserved segment on either porcine chromosome 4 (SSC4) or 14 (SSC14). We investigated linkage between OD and SSC4- and 14-specific microsatellite loci in order to map the OD locus. Twenty-seven informative meioses in families from one sire and three dams revealed linkage of od with microsatellites SW857 and S0089, located in the subcentromeric region of SSC14. We isolated part of the GULO gene of the pig by screening a porcine genomic library using a pig GULO cDNA as a probe, and mapped it to SSC14q14 by fluorescence in situ hybridization (FISH). Thus, the porcine GULO gene is both a good physiological and positional candidate gene for vitamin C deficiency in pigs.

[Selection of the method of surgical approach in plate osteosynthesis of mandibular fractures]. / A mütéti feltárás megválasztása állkapocstörések lemezes oszteoszintézisekor.

BACKGROUND: Plateosteosynthesis by intraoral approach of mandibular fractures gives the best cosmetical result but presents a rather difficult procedure. AIMS: Comparison of intra- versus extraoral approach in plateosteosynthesis of mandibular fractures. METHODS: Plate type, experience of the surgeon, age and sex of the patient, as well as hospital stay and rate of the septic complications were analysed retrospectively in 248 patients of the OMF Department (University Freiburg) with mandibular fractures with respect in view of the operative approach used. RESULTS: The method of osteosynthesis was found to be the strongest determinant. Concerning the surgical approach significant correlation was found between age and sex, and surgical experience. Operative approach was found to have no effect on hospitalization and septic complications. CONCLUSION: Operative approach does not have either medical nor economical consequences in the surgical management of mandibula fractures.