Effects of dietary protein concentration on performance and nutrient digestibility in Pekin ducks during aflatoxicosis.

A 14-d study was conducted to determine the impact of dietary crude protein concentration on performance, serum biochemistry, and nutrient digestive functions in Pekin ducklings during aflatoxicosis. A total of 144 male Pekin ducklings were randomly allotted to 4 dietary treatments arranged in a 2×2 factorial with 2 crude protein (CP) (20 and 24% on an analyzed basis) with or without 0.2 mg/kg aflatoxin B1 (AFB1) (0.21 mg/kg analyzed). The AFB1 reduced BW gain, feed intake, and breast muscle weight by 33 to 43% (P<0.0001). Serum concentration of protein, glucose, and Ca were also decreased by AFB1 (P≤0.0015), while pancreatic activities of amylase and lipase were increased by AFB1 (P<0.005). Apparent N digestibility was not affected by dietary treatment, whereas apparent ileal digestible energy was reduced 7.6% by AFB1 (P=0.0003). Higher dietary CP improved BW gain, gain:feed ratio, and breast muscle weight (P≤0.021), and tended to improve feed intake (P=0.094), but did not improve serum measures, digestive enzyme activity, or nutrient digestibility. No statistical interaction of AFB1 by CP was observed for any measures. Results from the current study suggest that AFB1 at low concentration can significantly impair performance of Pekin ducklings primarily through inhibited feed intake, as well as influence nutrient digestion processes (jejunum morphology, digestive enzyme activity, and apparent energy digestibility). Higher dietary CP can improve growth performance of ducklings regardless of AF exposure, but did not interact with dietary AFB1 on performance, serum biochemistry, or nutrient digestion in Pekin ducklings from hatch to 14 d.

Wildfire responses to abrupt climate change in North America.

It is widely accepted, based on data from the last few decades and on model simulations, that anthropogenic climate change will cause increased fire activity. However, less attention has been paid to the relationship between abrupt climate changes and heightened fire activity in the paleorecord. We use 35 charcoal and pollen records to assess how fire regimes in North America changed during the last glacial-interglacial transition (15 to 10 ka), a time of large and rapid climate changes. We also test the hypothesis that a comet impact initiated continental-scale wildfires at 12.9 ka; the data do not support this idea, nor are continent-wide fires indicated at any time during deglaciation. There are, however, clear links between large climate changes and fire activity. Biomass burning gradually increased from the glacial period to the beginning of the Younger Dryas. Although there are changes in biomass burning during the Younger Dryas, there is no systematic trend. There is a further increase in biomass burning after the Younger Dryas. Intervals of rapid climate change at 13.9, 13.2, and 11.7 ka are marked by large increases in fire activity. The timing of changes in fire is not coincident with changes in human population density or the timing of the extinction of the megafauna. Although these factors could have contributed to fire-regime changes at individual sites or at specific times, the charcoal data indicate an important role for climate, and particularly rapid climate change, in determining broad-scale levels of fire activity.

Centennial Review: History and husbandry recommendations for raising Pekin ducks in research or commercial production.

By some accounts, ducks were domesticated between 400 and 10,000 yr ago and have been a growing portion of the poultry industry for decades. Ducks specifically, and waterfowl in general, have unique health, housing, nutrition and welfare concerns compared to their galliform counterparts. Although there have been many research publications in regards to health, nutrition, behavior, and welfare of ducks there have been very few reviews to provide an overview of these numerous studies, and only one text has attempted to review all aspects of the duck industry, from breeders to meat ducks. This review covers incubation, hatching, housing, welfare, nutrition, and euthanasia and highlights the needs for additional research at all levels of duck production. The purpose of this review is to provide guidelines to raise and house ducks for research as specifically related to industry practices.

A feed restriction milieu for Pekin meat ducks that may improve gait characteristics but also affects gut leakiness.

In a previous study, we demonstrated that a 15% feed restriction (FR) during the first 2 wk after hatch could improve gait in Pekin meat ducks, but did result in reduced breast mass. We hypothesized that feed restriction after day 5 following muscle satellite cell development would allow the full growth of the breast meat. To accomplish this goal, 300 1-day-old ducklings (Maple Leaf Farms Inc.) were randomly allocated to 1 of the 3 groups (n = 4 pens, 25 ducks per pen): (1) Control group fed to ad libitum; (2) 85% daily feed intake from days 1 to 14 (FR 85% 1-14); 85% daily feed intake from days 5 to 14 (FR 85% 5-14). All ducks were vaccinated with inactivated Salmonella enteritidis on day 14 and boosted on day 26. The FR 85% 5-14 did show similar production standards to controls, and improved gait characteristics (P < 0.05). To determine if the partial feed restriction would have an impact on intestinal epithelial tight junction integrity, we treated ducks on days 7, 14, 21, 28, and 35 with 8.32 mg/kg FITC-d in water per os and blood samples were obtained via the tibial vein 1 h later. Serum samples were analyzed for presence and quantification of FITC-d. Feed restriction elicited a significant increase in FITC-d permeability at all points of evaluation. Anti-S. enteritidis specific IgY responses were assessed by ELISA from serum collected at 14 D, 28 D, and 35 D. Although all ducks showed an increase humoral immune response to the S. enteritidis, both feed restricted groups showed reduced IgY production compared to ad lib controls. Our data suggest that although the FR 5-14 feed restriction paradigm may reduce gait abnormalities without affecting production rates, some challenges exist due to increased gut leakiness or decreased acquired immune activity. Future studies will look at altering the feed restriction milieu to ameliorate these challenges.

Hybrid ape offspring of a mating of gibbon and siamang.

The serendipitous mating of a male gibbon, Hylobates moloch, and a female siamang, Symphalangus syndactylus, has produced two female offspring born 1 year apart. The hybrid karyotype of 47 chromosomes comprises the haploid complements of the parental species, 22 for the gibbon and 25 for the siamang. Chromosomal G and C banding comparisons revealed no clear homologies between the parental karyotypes except for the single chromosome in each species containing the nucleolus organizer region. The lack of homology suggests that the structural rearrangement of chromosomes has played a major role in the process of speciation for these lesser apes.

Nutrient and energy utilization in enzyme-supplemented starter and grower diets for White Pekin ducks.

The aim of this study was to determine the effect of enzyme supplementation on energy and nutrient utilization in White Pekin ducks fed starter and grower diets. In each of 2 experiments, 8 ducks were assigned to each starter or grower diet without or with enzyme supplementation at 1 g/kg of diet in a 2 x 2 factorial arrangement of treatments for a 120-h nutrient utilization assay. Starter and grower diets in experiment 1 contained 3.68 and 2.51% N, respectively, and 4.321 and 4.274 kcal/ g of gross energy, respectively. Corresponding values in experiment 2 were 2.93 and 2.89% and 3.994 and 3.930 kcal/g. The enzyme supplement was a cocktail containing 7,500 units of protease and 44 units of cellulase per gram. Endogenous energy losses were from 23 to 44 kcal in the 2 experiments, and endogenous amino acid (AA) losses ranged from 14 mg for Trp to 137 mg for Asp. In experiment 1, a lower energy output of ducks fed the grower diet, coupled with lower N output, resulted in greater (P < 0.05) diet AME(n) for the grower than the starter diet. Apparent digestibilities of all AA were higher (P < 0.05) in the starter diet than in the grower diet regardless of enzyme supplementation, more so for the S-containing AA. Average true digestibility of all AA was 93.7 and 90.4% for the starter and grower diets, respectively. There was no effect of enzyme supplementation of diet on the true digestibility of AA except for Met. Average true digestibility of all AA for diets not supplemented or supplemented with enzyme were 91.3 and 92.8%, respectively. In experiment 2, energy utilization of the grower diet was higher (P < 0.05) than that of the starter diet. Lysine and Asp showed lower (P < 0.05) apparent digestibility in the grower than in the starter diet. Enzyme supplementation of starter or grower diets did not affect the apparent digestibility of AA, except for Met, whose digestibility was increased by 2.4 percentage points in an enzyme-supplemented diet (P < 0.05). Except for Trp, true digestibility of AA was not affected by diet type or enzyme supplementation. The results show that the enzyme cocktail evaluated improved AA and energy utilization in White Pekin ducks and that such an enzyme-related response is diet composition-dependent.

Functional evaluation of a PTSD-associated genetic variant: estradiol regulation and ADCYAP1R1.

Posttraumatic stress disorder (PTSD) affects 5-10% percent of the US adult population with a higher prevalence among women compared with men. Although it remains unclear how biological sex associates with susceptibility to PTSD, one mechanism may involve a role for estrogen in a gene by environment interaction. We previously demonstrated a sex-dependent association between the pituitary adenylate cyclase-activating polypeptide type 1 receptor (PAC1) and PTSD, where carriers of a C allele at single-nucleotide polymorphism (SNP) rs2267735 within the PAC1 receptor gene (ADCYAP1R1) have increased symptoms of PTSD. This SNP is located within a predicted estrogen response element (ERE), which regulates gene transcription when bound to estradiol (E2) activated estrogen receptor alpha (ERα). In the current study, we examined E2 regulation of ADCYAP1R1 in vitro, in cell culture, and in vivo in mice and humans. We find in mice that fear conditioning and E2 additively increase ADCYAP1R1 expression. In vitro, we show that E2/ERα binds to the ADCYAP1R1 ERE, with less efficient binding to an ERE containing the C allele of rs2267735. In women with low serum E2, the CC genotype associates with lower ADCYAP1R1 expression, which further associates with higher PTSD symptoms. These findings lead to a model in which E2 induces the expression of ADCYAP1R1 through binding of ERα at the ERE as an adaptive response to stress. Inhibition of E2/ERα binding to the ERE containing the rs2267735 risk allele results in reduced expression of ADCYAP1R1, diminishing estrogen regulation as an adaptive stress response and increasing risk for PTSD.

Identification of apoB-containing lipoprotein families in NIDDM.

The purpose of this study was to determine the concentrations and composition of apoB-containing lipoprotein families in whole plasma and major lipoprotein density classes of a selected group of Native Americans from northeastern Oklahoma with non-insulin-dependent diabetes mellitus. The measurement of lipoprotein density classes showed that the total lipoprotein mass of very-low-density lipoproteins was significantly higher and that of high-density lipoproteins significantly lower in diabetic patients than nondiabetic control subjects regardless of their plasma triglyceride levels. The VLDLs were enriched with TG, free cholesterol, and apolipoproteins C-III and E. HDLs were enriched with TG but depleted of apoC-III and apoE. There was no change in the levels of TG-enriched low-density lipoproteins. Fractionation of VLDL by sequential immunoprecipitation with antisera to apoE and apoC-III established that increased concentrations of this density class in diabetic patients are due to elevated levels of TG-rich lipoprotein LP-B:C and lipoprotein LP-B:C:E. The levels of LP-B:C particles were increased more than the levels of LP-B:C:E particles. The LDLs were characterized by a slight increase in TG-enriched lipoprotein B and no change in the levels of LP-B:C and LP-B:C:E. There was no difference between diabetic patients with or without vascular disease in the levels of LP-B and LP-B:C:E. However, patients with vascular disease had higher concentrations of LP-B:C particles in VLDL and whole plasma than patients without vascular disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Binding of naloxone to human T lymphocytes.

Purified T lymphocytes have a specific binding site for naloxone, the opiate antagonist. The KD for the site was 50.6 +/- 2.4 nM, while the Hill coefficient (n) was 1.67 +/- 0.16, indicating a degree of positive cooperativity of ligand binding. The bound naloxone was partially displaceable by various opiate agonists including morphine (56%), beta-endorphin (61%), met5- and leu5-enkephalin (40% each), [D-ala2, D-leu5]-enkephalin (78%) and [D-ala2, D-leu5]-enkephalinamide (66%). Virtually all of the binding capacity was recovered in the particulate membrane fraction after sonic lysis of the cells. There was great interindividual variability in Bmax between samples, suggesting a possible mechanistic basis for the variability in drug action seen between different individuals.

Perfluoropropane gas, modified panretinal photocoagulation, and vitrectomy in the management of severe proliferative vitreoretinopathy.

Seventy-six consecutive patients with total rhegmatogenous retinal detachments and severe proliferative vitreoretinopathy underwent combined pars plana vitrectomy, lensectomy, panretinal photocoagulation, perfluoropropane gas (C3F8)/fluid exchange, and scleral buckling. Sixty-two (82%) of the patients had successful, sustained (greater than 12 months) posterior retinal reattachments at last examination. Of these 62 patients, 40 (65%) had complete retinal attachment, with no evidence of regrowth of periretinal membranes or redetachments following the initial procedure. In the remaining 22 cases with successful reattachment of the retina posterior to the equator, partial peripheral retinal detachments were observed. In 16 of the 22 cases, the detachments occurred entirely anterior to the boundary of the previously placed photocoagulation lesions. The posterior retina remained uninvolved, and no further treatment was needed. Reoperation was required in the other six patients to achieve sustained posterior retinal reattachment. Postoperative visual acuity ranged from 20/40 to bare light perception, with 69% of the anatomically successful cases obtaining functional visual acuity (greater than 20/400). Failures were related to reproliferation of fibrous membranes.

Detection of opiate-enhanced increases in DNA damage, HPRT mutants, and the mutation frequency in human HUT-78 cells.

In previous studies we have shown highly significant increases in chromosome damage and sister chromatid exchanges in heroin addicts, particularly when caffeine and metabolic inhibitors are added to the medium. Using human HUT-78 T-cell cultures, we now find direct in vitro evidence of opiate-induced or opiate-promoted mutagenesis via several assay systems. First, with microgel electrophoresis (MGE), we observed graded, dose-dependent, significant increases (P < .0001) in the frequency of comet tails of fragmented DNA when cells were treated with morphine alone (5 x 10(-9) M up to 10(-7) M) or when co-treated with the more potent mutagen, ethylmethanesulfonate (EMS). There were also dose-dependent increases in the lengths and densities of the comet tails observed. These findings were confirmed by a series of MGE experiments in which several days of morphine exposure preceded a 2-hr pulse of EMS. Second, mutant frequency (MF) assays also indicated significant opiate effects. These studies required separate assessment of cloning efficiencies and the frequencies of TG-resistant, HPRT-deficient mutant clones under four test conditions: no treatment, morphine alone for 4 days, morphine plus EMS, and EMS alone. Prior to the treatment phase, aminopterin was used to eliminate background HPRT mutations. The medium was changed after the treatment phase, the cells were allowed to express mutant phenotypes, and then TG was added and resistant mutant clones counted after 16 days. The background MF level for controls and for cells treated with EMS alone were negligible at 5.12 x 10(-8) and 7.25 x 10(-8), respectively. In the cells treated with morphine alone or morphine plus EMS, MF levels increased very significantly (P < .001) by > 100-fold to 5.1 x 10(-6) and 7.0 x 10(-6), respectively. Cloning efficiency also decreased significantly with both morphine-exposed conditions. Preliminary analysis with the single strand conformational polymorphism (SSCP) procedure following 6-thioguanine (TG) selection, also confirmed the occurrence of Exon 3 mutants of the HPRT gene in cells exposed to morphine plus EMS. It appears that brief EMS exposure can be repaired, whereas, if morphine exposure persists through one or more cell cycles, direct or indirect mutagenesis is initiated.

Increased chromosome damage in pediatric heart catheterization patients after diagnostic fluoroscopy and cineangiography.

Chromosome damage (CD) and sister chromatid exchange (SCE) levels were studied in lymphocytes from 30 pediatric heart catheterization patients receiving radiation during diagnostic fluoroscopy and cineangiography procedures. Forty-eight-hour CD and 72-hr SCE cultures were prepared from sequential samples taken from each patient: samples 1-3 via the catheter the same day (1) before exposure, (2) after fluoroscopy, and (3) after cineangiography; and sample 4 by venipuncture the next morning. Significant increases in CD (dicentrics, rings, and fragments), but not SCE, were observed. From a mean base level of 0.4% cells with CD, the CD levels increased 2-3-fold in samples 3 and 4 (p = .001). Rings only occurred in samples 3 and 4. While increased CD levels also correlated with increasing age, body surface area, and weight, partial correlations controlling for these factors clearly indicate that the CD effects are principally attributable to the radiological procedures (p = .001). Increased CD levels correlated with both the roentgen dose of cineangiography exposure (p = .002) and the volume of contrast medium (p = .000); however, partial correlations, controlling for either factor, indicate that the contrast medium was the principal factor (p = .006).

A dental fears typology of oral surgery patients: matching patients to anxiety interventions.

Two studies are described in which dental patients were administered the Dental Fear Survey (DFS) and then received 1 of 5 anxiety reduction interventions to prepare them for extraction of 3rd-molar teeth. Interventions included standard clinic treatment, oral premedication, and several relaxation-based procedures. Dependent variables were self-reported and observer-rated distress. In the 1st study (N = 231), cluster analyses of the DFS subscales revealed that patients could be subtyped as low-fear, high-fear, or cue-anxious patients who admitted fear only in response to specific stimuli. Dental fear subtypes were distinguishable by situational cognitions reported, and fear subtype interacted with anxiety intervention to predict distress. These results were replicated in the 2nd study (N = 150). The results are seen as supportive of a multidimensional view of dental anxiety.

A technique for improving corneal clarity during retinal surgery.

To maintain corneal clarity during scleral buckling operations, the surgeon firmly rolls a dry cotton applicator across the edematous corneal surface, and the epithelial edema fluid is pressed out and absorbed by the applicator. This technique, which may be repeated a number of times, reduces the number of cases that require removal of the epithelium.

Coping with oral surgery by self-efficacy enhancement and perceptions of control.

Recent work has suggested that patients' coping could be improved in stressful dental situations if perceptions of self-efficacy and control could be enhanced. To test this hypothesis, 70 first-time third-molar extraction patients were randomly assigned to one of four surgery preparation conditions: standard preparation, oral premedication, relaxation, and a relaxation+efficacy-enhancing feed-back condition in which subjects were given false galvanic skin response (GSR) biofeedback leading them to believe that they were highly skilled at relaxing. Analyses indicated that: (1) all treatments were seen as equally credible (controlling for placebo effects); (2) a priori contrasts showed that both the relaxation-only treatment and the relaxation+efficacy-enhancement treatment were superior to the premedication and standard preparations in raising coping self-efficacy; (3) regardless of treatment condition, increase in reported coping self-efficacy was significantly correlated with pre-operative anxiety, with self-reported peri-operative distress, and with behavioral ratings of peri-operative distress; and (4) the relaxation treatments resulted in lower pre-operative anxiety than the other interventions, and linear contrasts showed significant trends in which the relaxation+efficacy-enhancing condition was superior to the relaxation-only condition, which was in turn superior to the medication condition and the standard preparation in reducing both pre-operative anxiety and behavioral ratings of peri-operative distress. It was concluded that thoughts related to self-confidence and control can be manipulated, and that these thoughts can in part determine how well a person copes in stressful dental situations.

Microsurgical management of macular epiretinal membranes (macular pucker).

Surgical management of selected macular epiretinal membranes is possible through the use of microsurgical pars plana vitreoretinal membranectomy. Visual improvement can be significant with resolution of traction retinal detachment and retinal distortion. Complications are similar to other forms of vitreous surgery. In a series of 9 selected cases with severe reduction of visual acuity secondary to macular pucker, microsurgical membranectomy was performed with encouraging results.

Enhanced assays detect increased chromosome damage and sister-chromatid exchanges in heroin addicts.

To refine previous studies of chromosome damage (CD) and sister-chromatid exchanges (SCE) in heroin addicts, we applied new methods developed in our laboratory to enhance detection of the cytogenetic effects of low-level radiation exposure in hospital workers. For CD analysis, we applied our thymidine-fluorodeoxyuridine-caffeine (TFC) enhancement procedure in which cells at setup receive 1 x 10(-7) M fluorodeoxyuridine to inhibit thymidylate synthetase and 4 X 10(-5) M thymidine to satisfy the induced requirement, and then in G2 receive 2.2 mM caffeine to modulate DNA repair. For SCE enhancement, caffeine treatment was initiated in G1 at 19 h before harvest. Using both standard and enhanced procedures for CD and SCE analysis, blood samples were evaluated from 20 street heroin addicts and 22 controls. Standard 2-day CD and 3-day SCE assays showed small, insignificant genotoxic increases in addicts while the enhanced CD and SCE assays showed highly significant increases. Most CD events were in the form of chromatid and chromosome breaks. There were no rings and only a few dicentrics were observed in the TFC-enhanced cultures. Although quadriradials are rare, 10 were found in addict TFC-cultures and 3 in control TFC-cultures. With the standard CD assay, the mean number of chromosome breaks per 100 cells was 0.727 for controls and 1.056 for addicts (not significant). With the TFC-enhanced assay, the same measure showed 1.483 chromosome breaks for controls and 5.143 for addicts (highly significant, ANOVA: p less than 0.0001). A highly significant difference was also observed for chromatid-type damage with the TFC-enhanced assay (chromatid breaks per 100 cells: 16.793 for controls; 48.191 for addicts). The SCE data also showed significant differences with the enhanced assay. Scoring 25 cells/condition, standard SCE cultures showed 10.892 SCE/cell for controls and 11.732 SCE/cell for addicts (not significant). With CAF enhancement there were 13.08 SCE/cell for controls and 17.05 SCE/cell for addicts (ANOVA: p less than 0.008). These findings indicate that detection of CD and SCE effects can be significantly enhanced by the use of these new procedures. The finding of greatly increased chromatid damage in the addicts with the TFC procedure suggests that at least part of the CD detected occurred in vitro and is not a product of prior in vivo damage. Therefore exposure to this drug and perhaps other environmental agents may not only leave a residue of DNA or chromosome damage but may also induce a sensitivity to further genotoxic damage that is revealed by using the enhanced procedures.

Parallel increases in sister-chromatid exchanges at base level and with UV treatment in human opiate users.

The SCE base level frequency and SCE levels induced by far-UV (254 nm) treatment of cells in early G1 and early S phases of the cell cycle were significantly higher in leukocytes from heroin addicts as compared to controls. The increased SCE levels in addicts was greatest at base level and smallest after UV irradiation of cells in S phase. These results corroborate and extend our previous findings of increased chromosome damage and reduced DNA-repair synthesis in heroin users. Since opiates do not directly damage DNA, the elevated cytogenetic effects associated with opiate use probably arise from secondary promotional effects related to opiate-mediated alterations in leukocyte metabolism.

Gustatory function after third molar extraction.

OBJECTIVE: The purpose of this study was to determine the severity and time course of taste changes after extraction of all 4 third molars. STUDY DESIGN: Taste function in 17 patients was measured before third molar surgery and at 1 month and 6 months after surgery. Two tests were administered: a whole-mouth, above-threshold test in which subjects sipped, expectorated, and then rated the intensities and identified the taste qualities of various solutions, and a localized test in which subjects rated and identified solutions painted with cotton swabs on different oral sites. RESULTS: Intensity ratings for solutions in the whole-mouth test were reduced by approximately 14% for NaCl, citric acid, and quinine hydrochloride at 1 month after surgery and had not recovered by 6 months after surgery for citric acid (P<.02). The taste quality of NaCl was identified correctly less frequently after third molar extraction. Perceived taste intensity on discrete areas of the tongue was significantly reduced after surgery (P<.05). Patients with the most severely impacted molars gave the lowest taste intensity ratings to whole-mouth test solutions at 6 months after surgery (P<.02). In contrast, taste function in a group of subjects who received only local dental anesthesia was not affected. CONCLUSIONS: Gustatory deficits occur after third molar extraction, persist for as long as 6 months after surgery, and appear to be associated with depth of impaction.

Respiratory emergencies in the dental office.

Respiratory emergencies are among the most common problems encountered in dental practice and are potentially among the most devastating. Therefore, they must be recognized rapidly and treated promptly. This article focuses on the clinically significant pathophysiology of respiratory emergencies, such that the practitioner can effectively identify the patients with a risk of developing a respiratory crisis and use this information to help provide rapid, effective therapy. Simple protocols are presented for the treatment of the most common respiratory emergencies.