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PubMed1991

Evidence for the involvement of central serotonin in mechanism of domestication of silver foxes.

Silver foxes selected for more than 30 years for tame behavior and displaying no defensive reaction to human contact were shown to have a higher serotonin level in midbrain and hypothalamus, and a higher 5-hydroxyindole acetic acid (5-HIAA) content in midbrain, hypothalamus and hippocampus in comparison to nonselected wild silver foxes bred in captivity over the same time span. Tryptophan hydroxylase (TPH) activity in midbrain and hypothalamus in domesticated foxes was increased as compared with their aggressive/defensive counterparts. Monoamine oxidase type A (MAO A) activity was was decreased with an increased Km and unchanged Vmax in domesticated foxes. No changes in specific [3H]ketanserin or [3H]8-OH-DPAT binding in frontal cortex was revealed. A reduced density (Bmax) of 5HT1A receptors in hypothalamic membranes in domesticated foxes was shown. It is suggested that the brain serotonergic system is involved in the mechanism of domestication converting wild aggressive/defensive animals into tame ones.

Aggression↗
PubMed2005

Diverse aging rates in metazoans: targets for functional genomics.

Aging, or senescence, has typically been measured by demographic analysis, which has its merits but is blind to key aspects of functional development and deterioration. If one uses demographic analyses, however, the approach providing most insight is the analysis of age-specific mortality. The continuing increase in DNA sequencing power combined with emerging computational techniques will allow in the near future detailed investigation of mechanisms of aging in diverse species beyond the typical laboratory bestiary. A comparative approach of this sort needs to consider, in addition to simple longevity, the effects of phylogeny and body size on the species in question. Insight may be gained from the study of species exhibiting accelerated aging relative to more "typical" species. These naturally short-lived species, such as several small shrews and marsupials, avoid the worry inherent in "accelerated aging" genotypes of common models, which is that they are only short-lived because of some idiosyncratic pathology unrelated to general aging. A case of special interest that has yet to be seriously investigated is the domestic dog, in which selective breeding has produced phenotypes within the same species that age at two-fold different rates. Exceptionally long-lived species offer exceptional opportunities to discover whether there are few or many ways to create long-lived organisms. Slow-aging species with the most to offer include bats and naked mole-rats. Perhaps no fundamental question in biology is more intriguing that why and how nature has produced such a dazzling array of aging rates. The development of functional genetics over the next several decades promises to lead us toward an answer.

Animals↗
PubMed2006

Targeting low-arsenic aquifers in Matlab Upazila, Southeastern Bangladesh.

Groundwater with high concentration of geogenic arsenic (As) occurs extensively in the Holocene alluvial aquifers of Bangladesh. Local drillers in Matlab Upazilla are constructing deeper tubewells than in the recent past, primarily because of low concentrations of dissolved Fe and As. Locally a thick layer of black to grey sediments overlies an oxidised unit of yellowish-grey to reddish-brown sediments. The correlation between the colour of both units and the groundwater redox conditions was investigated to provide an easy tool for targeting low-arsenic groundwater. Based on the sediment colour at the screen depths described by local drillers, 40 domestic shallow tubewells were selected for water sampling. Four colours were used to describe the sediments: black, white, off-white (buff) and red. Generally, the groundwater was anoxic and the As concentrations ranged from less than 5.2 to 355 microg/L. Water derived from the black sediment is characterized by relatively higher concentrations of dissolved NH(4)(+), DOC, Fe, P, As and by low Mn and SO(4)(2-) concentrations. The off-white and red sediments had high concentration of Mn and low NH(4)(+), DOC, Fe, P and As concentrations. The water abstracted from the black sediments indicated the most reducing environment, followed by white, off-white and red respectively. Three boreholes verified the driller's perception of the subsurface lithologic conditions. Discrepancies between the driller's and the research team description of the sediment colours were insignificant. This study shows that sediment colour is a reliable indicator of high and low-As concentrations and can be used by local drillers to target low-arsenic groundwater.

Arsenic↗
PubMed2001

The domestication syndrome within Hybrid Perpetuals roses: the effect of unconscious selection on flavonoids.

Cultivated GallicanaexChinenses hybrids of roses, namely Hybrid Perpetuals, were compared with their parents as to morphology, petal colour, flavonol and anthocyanin metabolism. Morphology exhibited clear patterns of hybridity. An objective measure of petal lightness (L) indicated that Hybrid Perpetuals were submitted to a selection pressure favouring dark-flowered cultivars. When compared to the parental flavonoid metabolisms, Hybrid Perpetuals exhibited increased synthesis of anthocyanin and quercetin. High amounts of anthocyanin in Hybrid Perpetuals resulted from the selection of deeper-coloured flowers. High amounts of quercetin were correlated with enhanced anthocyanin synthesis, so that this originality of the flavonol metabolism was interpreted on biogenetic ground as a repercussion of this same selection pressure. Finally, the patterns of variation of flavonol glycosides within the Hybrid Perpetuals reflected the indirect selection pressure for the quercetin end-products, and with the ancestral hybridizations for the kaempferol derivatives.

Journal Article↗
PubMed2001

The evaluation of rhytidectomy flap healing after CO2 laser resurfacing in a pig model.

OBJECTIVE: This study was conducted to determine when it becomes safe to perform laser resurfacing after rhytidectomy flap elevation. STUDY DESIGN: Eighty-four sites on 12 domestic Yorkshire pigs were selected; 4 x 10-cm skin flaps were elevated in 72 of the 84 sites and shortened 10%. The 12 remaining sites (controls) were treated with laser resurfacing alone. Laser resurfacing was also performed at days 0, 7, 14, 21, and 28 after closing the skin flaps. The healing time for the laser-resurfaced sites without flap elevation were compared to that of the skin flaps treated with the laser at days 0, 7, 14, 21, and 28. Twelve "skin flap" controls were elevated, shortened 10%, and closed without laser treatment. Resurfacing was performed using 2 passes with the Sharplan Silk Touch CO(2) laser. RESULTS: The average healing time for the skin flaps treated with the laser at day 0 was 23.9 days. All of these flaps showed skin slough with delayed healing followed by scar formation. The areas treated with the laser alone (controls), and the subsequent skin flaps treated with the laser postoperatively at days 7, 14, 21, and 28 days completely re-epithelialized in an average of 7.8, 8.1, 7.3, 7.4, and 7.3 days, respectively. There were no statistically significant differences in healing time between the controls and flaps treated with the laser on or after 7 days (P > 0.05). However, there were statistically significant differences in healing time between the laser-treated skin flaps at day 0 and the controls, between the laser-treated flaps on day 0 and day 7, and between the laser-treated flaps on day 0 and day 14 (P < 0.001). Because there was little difference in healing time after 14 days, only the healing times for laser-treated skin flaps up to 14 days were compared using paired t tests. CONCLUSIONS: From our observations using a pig model, we conclude that skin flaps may be safely laser resurfaced about 1 week postoperatively. On the other hand, simultaneous flap elevation and laser resurfacing results in delayed healing with subsequent scar formation.

Analysis of Variance↗
PubMed1987

Withdrawal of zinc oxide-containing diets from mature, female domestic fowl: effects on laying performance and the weights of selected tissues.

1. Two hundred and sixteen laying hens of two strains were given diets containing ZnO to provide 0, 0.5, 0.75, 1.00, 1.25, 1.50, 2.00, 3.00 or 4.00 g added Zn/kg. These diets were given ad libitum for 5 consecutive 28-d periods. All hens subsequently received the control diet with no added ZnO for 5 weeks. 2. Four hens from each treatment were killed 0, 1 and 5 weeks after substitution of the ZnO-supplemented diets by the control diet. 3. The adverse effects of the ZnO-containing diets on body weight, food intake, egg production, pancreas, gizzard, oviduct and ovary weights/kg body weight were reversed by removal of the ZnO from the diets. 4. Five weeks after withdrawal egg production of the group which had received the diet with the highest concentration of added ZnO was only 50% of that of the control birds. 5. The beneficial effect of the added ZnO on internal egg quality was not maintained after withdrawal of the ZnO-containing diets.

Animals↗
PubMedDate not supplied

Quantitative prediction of biodegradability, metabolite distribution and toxicity of stable metabolites.

An evaluation of the capability of organic chemicals to mineralize is an important factor to consider when assessing their fate in the environment. Microbial degradation can convert a toxic chemical into an innocuous one, and vice versa, or alter the toxicity of a chemical. Moreover, primary biodegradation can convert chemicals into stable products that can be difficult to mineralize. In this paper, we present some new results obtained on the basis of a recently developed probabilistic approach to modeling biodegradation based on microbial transformation pathways. The metabolic transformations and their hierarchy were calibrated by making use of the ready biodegradability data from the MITI-I test and expert knowledge for the most probable transformation pathways. A model was developed and integrated into an expert software system named CATABOL that is able to predict the probability of biodegradation of organic chemicals directly from their structure. CATABOL simulates the effects of microbial enzyme systems, generates the most plausible transformation pathways, and quantitatively predicts the persistence and toxicity of the biodegradation products. A subset of 300 organic chemicals were selected from Canada's Domestic Substances List and subjected to CATABOL to compare predicted properties of the parent chemicals with their respective first stable metabolite. The results show that most of the stable metabolites have a lower acute toxicity to fish and a lower bioaccumulation potential compared to the parent chemicals. In contrast, the metabolites appear to be generally more estrogenic than the parent chemicals.

Animals↗
PubMed2004

Methylprednisolone enhances contraction of porcine femoral head epiphyseal arteries.

The pathomechanism of steroid-induced femoral head necrosis is thought to be disturbed femoral head blood flow. We hypothesize that methylprednisolone increases vasocontraction of femoral head epiphyseal arteries, thereby reducing femoral head blood flow. Nine immature female domestic pigs were randomly selected from a group of 18 to receive 24-hour methylprednisolone treatment, whereas the nine remaining pigs received the placebo control in a blinded fashion. After sacrifice, lateral epiphyseal artery segments from the femoral heads were mounted as ring preparations on a small vessel myograph. Isometric active tension was measured in relation to cumulating doses of the vasoconstrictors noradrenaline and endothelin-1, and the vasodilator bradykinin. Vasocontraction to noradrenaline was not altered by methylprednisolone. Bradykinin elicited a concentration-dependent vasodilation which was lower in the corticosteroid-treated vessels. Vasoconstriction to endothelin-1 was stronger in the corticosteroid-treated vessels. Our data indicate that methylprednisolone enhances contraction of femoral head lateral epiphyseal arteries and may decrease femoral head blood flow. To our knowledge, this pathomechanic factor in femoral head necrosis has not been described before.

Animals↗
PubMed2006

Practice of universal precautions among healthcare workers.

INTRODUCTION: Healthcare workers (HCWs) are exposed to bloodborne infections by pathogens, such as HIV, and hepatitis B and C viruses, as they perform their clinical activities in the hospital. Compliance with universal precautions has been shown to reduce the risk of exposure to blood and body fluids. This study was aimed at assessing the observance of universal precautions by HCWs in Abeokuta, Ogun State, Nigeria. SUBJECTS AND METHODS: The study was conducted in September 2003 in Abeokuta metropolis, Ogun State, Nigeria. The respondents were doctors, trained and auxiliary nurses, laboratory scientists and domestic staff. They were selected through a multistage sampling technique from public and private healthcare facilities within the metropolis. The instrument was an interviewer-administered, semistructured questionnaire that assessed the practice of recapping and disposal of used needles, use of barrier equipment, handwashing and screening of transfused blood. RESULTS: There were 433 respondents, 211 (48.7%) of which were trained nurses. About a third of all respondents always recapped used needles. Compliance with nonrecapping of used needles was highest among trained nurses and worst with doctors. Less than two-thirds of respondents (63.8%) always used personal protective equipment, and more than half of all respondents (56.5%) had never worn goggles during deliveries and at surgeries. The provision of sharps containers and screening of transfused blood by the institutions studied was uniformly high. A high percentage (94.6%) of HCWs observed handwashing after handling patients. The use of barrier equipment was variable in the institutions studied. CONCLUSION: Recapping of used needles is prevalent in the health facilities studied. Noncompliance with universal precautions place Nigerian HCWs at significant health risks. Training programs and other relevant measures should be put in place to promote the appropriate use of protective barrier equipment by HCWs at all times.

Blood-Borne Pathogens↗
PubMed1996

Stereological and allometric studies on mammalian cerebral cortex with implications for medical brain imaging.

Design-based stereological methods (the Cavalieri principle and vertical sectioning) have been used to estimate the volumes, surface areas and thicknesses of the cerebral cortex. Cortices of individual hemispheres were analysed in a selection of 31 adult domestic mammals (horses, oxen, pigs, goats, dogs, cats and rabbits). There were 13 females and 18 males. After correcting for fixation shrinkage effects, results were tested for species, laterality and sex differences using linear regression and analysis of variance. Mean body weights of domestic mammals varied from 4 kg to 460 kg and brain volumes from 11 cm3 to 603 cm3. Hemisphere dimensions varied between species but, except for volume (which exhibited a species x sex interaction effect), no other differences were detected. It is concluded that these mammalian brains are, in terms of their gross anatomy, symmetric and not sexually dimorphic. Apparent cortical thickness (measured directly on slices) proved to be a satisfactory estimate of true thickness (estimated by dividing cortical volume by the mean of outer and inner cortical surfaces). This has implications for medical slice images on which mean cortical thickness can be estimated only from apparent local thicknesses.

Analysis of Variance↗
PubMed1975

[Amebas of the Limax group in various species of farm and domestic animals].

Fourteen strains of amoebae of the Limax group were isolated by random selection in five species of farm and domestic animals. The amoebae were captured in the respiratory and digestive tracts and in sex organs. According to the systematic classification, the isolates belong to the following genera: Acanthamoeba, Hartmannella, and Vahlkampfia. Their temperature optimum was 37 degrees C. The trial to demonstrate a pathogenetic character of the representative of individual genera on laboratory animals gave a negative result.

Amebiasis↗
PubMedDate not supplied

[The noradrenaline content and the alpha 2-adrenoreceptor count in the brain of brown rats selected for the absence of aggressive behavior in relation to man].

Artificial selection of gray rats by the domestic type of behaviour resulted in an increase of the noradrenaline content, but in a decrease of the alpha 2-adrenergic receptors number in the hypothalamus. The data suggest a significant difference in noradrenergic system between domesticated and aggressive animals associated with changes in aggressive behaviour towards man during selection.

Aggression↗
PubMed2006

Behavioural trade-offs between growth and mortality explain evolution of submaximal growth rates.

1. The importance of body size and growth rate in ecological interactions is widely recognized, and both are frequently used as surrogates for fitness. However, if there are significant costs associated with rapid growth rates then its fitness benefits may be questioned. 2. In replicated whole-lake experiments, we show that a domestic strain of rainbow trout (artificially selected for maximum intrinsic growth rate) use productive but risky habitats more than wild trout. Consequently, domestic trout grow faster in all situations, experience greater survival in the absence of predators, but have lower survival in the presence of predators. Therefore, rapid growth rates are selected against due to increased foraging effort (or conversely, lower antipredator behaviour) that increases vulnerability to predators. In other words, there is a behaviourally mediated trade-off between growth and mortality rates. 3. Whereas rapid growth is beneficial in many ecological interactions, our results show the mortality costs of achieving it are large in the presence of predators, which can help explain the absence of an average phenotype with maximized growth rates in nature.

Animals↗
PubMed2006

Skeletal muscle fibre growth and growth associated myopathy in the domestic chicken (Gallus domesticus).

1. Genetic selection of broilers may have pushed muscle fibres to their maximum functional size constraints. Broiler (B), female great-grandparent (GGP) and layer (L) lines were weighed, blood sampled and killed from 5 to 25 weeks of age. 2. At 25 weeks, Pectoralis major (Pm) fibre size reached by the B (65.9 microm) and GGP (59.8 microm) were 1.5 times greater than the L (38.1 microm). In the B and GGP lines, fibre growth of the Pm markedly exceeded that of the Biceps femoris (Bf) muscle. However, in the L line, fibre growth of the Pm and Bf muscle was comparable. Connective tissue content was generally higher in the Bf than in the Pm of all lines. 3. Centralised nuclei were observed predominantly in Pm, and may regulate fibre size. Both large muscle fibres and inadequate capillary supply may induce metabolic stress in B and GGP lines due to the large diffusion distances for oxygen, metabolites and waste products. 4. Enzyme markers of muscle damage (creatine kinase (CK), lactate dehydrogenase (LDH) and aspartate aminotransaminase (AST)) and histopathological analysis of Pm and Bf indicated greater myopathy in B and GGP vs L. 5. Regenerative processes were associated with oestrogen secretion. Reduced CK and LDH preceded egg yolk precursor production and increased calcium uptake for eggshell synthesis in all three lines. Oestrogen may stimulate muscle fibre regeneration and recovery as a myo-protective adaptation to potentially detrimental changes in calcium economy during egg production.

Animals↗
PubMed1991

The effects of genetic selection for increased growth rate on mucosal and muscle weights in the different regions of the small intestine of the domestic fowl (Gallus domesticus).

1. The total organ weights and the constituent weights of mucosal and muscle tissues have been determined in the small intestines of three lines of domestic fowls subjected to different degrees of artificial genetic selection for rapid growth rates. 2. Effects of selection have been examined on the basis of wet and dry tissue weights in duodenum, jejunum and ileum from each line of birds. 3. Effects of selection have been compared on both absolute tissue weights and relative weights (i.e. expressed per kilogram body weight). 4. Selection for rapid growth rate is associated with increases in absolute weight and length of small intestine but marked reductions in relative weight and length. 5. In the fastest growing group of birds the major effect is a decrease in the relative mass of mucosa which is most pronounced in the more proximal regions of the small intestine. 6. These findings are discussed in relation to possible enhancement of intestinal digestive and absorptive efficiency in birds selected for improved growth rate and feed conversion. 7. The differences in tissue composition of the small intestine between lines and between regions of the intestine in the same line emphasise the difficulty in selecting an anatomical parameter upon which to base the in vitro and in vivo measurements of nutrient absorption in a number of established preparations.

Animals↗