Ageing in fishes

Fishes show three types of senescence. Lampreys, eels and pacific salmon exhibit rapid senescence and sudden death at first spawning. The guppy, red panchax, medaka, platyfish, Indian murrel and many other teleosts undergo gradual senescence, as observed in most of the vertebrates. A number of fishes (e.g. sturgeons, paddlefish, female plaice, flatfish, rockfish) show indeterminate growth, the occurrence of senescence in them is supposed to be very slow or negligible. Neuroendocrine mechanisms are involved in rapid senescence. Most of the evidences in favour of the occurrence of senescence in fishes have been derived from studies in species showing gradual senescence. Age-related increases in mortality rate, accumulation of lipofuscin, lipid peroxidation, collagen cross-linking and decreases in growth rate, reproductive capacity and protein utilisation are clearly marked in such species. Anatomical changes in various organs during ageing also confirm increases in degenerative changes and pathological symptoms. Dietary restriction and lower environmental temperature retard the ageing processes in a few species showing gradual senescence. These results tentatively support the contention of commonality in mechanism of ageing processes in vertebrates. At present, anatomical, cellular, biochemical and genetic evidences in support or against the occurrence of slow senescence or negligible senescence in long-lived fish species are almost nonexistent. Extensive studies on ageing in fishes are needed to explain the multiple mechanisms which are not unexpected considering the number and variety of the existing species.     

Ageing of bruising in children

The yield variations in fatty acid content, degree of acidity, peroxides, K270 and K232 indexes, the profile of the different fatty acids and alpha tocopherol were studied in different virgin olive oils obtained in the laboratory oil-mill. These different olive oils were pressed from the following olive varieties: Arbequina, Blanqueta, Empeltre, Frantoio, Hojiblanca, Manzanilla, Negral, Picual, and Royal, all of which were grown since being planted, on the same land, under the same growth conditions. The differences found must not be considered as absolute values but rather in comparative terms between the varieties. The greatest balance between the different parameters analyzed was seen in the Empeltre variety, which is that planted in greatest number in the trial area.     

Sex differences in the nervous system of reptiles

1. The study of sex differences in the brain and behavior of reptiles presents an excellent opportunity both to discern general principles of sexual differentiation in the nervous system and to explore the evolutionary history of this process in amniote vertebrates. 2. Findings in several reptiles suggest that some sex differences found in mammals and birds are conserved while others are not. Conserved features include areas in the limbic forebrain involved in the regulation of social and sexual behaviors. As in mammals and birds, it is rare to find differences in the distribution of sex steroid concentrating neurons in reptiles but common to find differences in the distribution of the various steroid hormone receptors and in their regulation. 3. This research has revealed that differences in social and sexual behavior are reflected better by the activity, not by the size, of hormone-sensitive limbic areas. 4. Finally, species differences in plasma levels of sex hormones are paralleled by differences in behavioral sensitivity to these hormones as well as by differences in the regulation of genes coding for steroid hormone receptors.     

Ageing and cancer

The process of carcinogenesis is complicated and in most cases requires several steps of cellular transformation resulting from various molecular signals brought about by interactions between carcinogens and the cellular genome. Cancers in which cellular transformation does not require numerous processes tend to occur in younger age groups while cancers of the advancing age tend to be those in which the process of cellular transformation occurs through complex molecular processes that require ample time for induction.     

A review of hearing in amphibians and reptiles.

There is behavioral evidence which indicates that frogs, toads, salamanders, alligators, and lizards can hear. Snakes apparently cannot hear and the issue is undecided in the case of the turtle. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Enterobacteria of reptiles (author's transl)

The aerobic gram-negative faecal flora of 78 reptiles consisting of 46 species (39 lizards of 23 species, 15 tortoises of 9 species, 24 snakes of 14 species) was studied. Salmonella was found to be present in 50% of lizards, in 16% of tortoises and in 16% of snakes. There were all together 15 different serotypes. Edwardsiella tarda was isolated in 20% of tortoises, in 12% of snakes but only in 3% of lizards. Tortoises represent therefore the possible normal habitat of Edwardsiella tarda. We isolated Arizona specially from snakes as was described by many authors. A new serotype (Arizona 26a, 26b:27 - 21 = S. arizonae 61:Z10:Z35) was found in a rattlesnake. There were found also much amounts of Citrobacter (52%), E. coli (50%), Proteus mirabilis (49%), Proteus morganii (18%), Proteus rettgeri (26%), Proteus vulgaris (32%). Klebsiella and Enterobacter seem to prefere the lizards. The overwhelming majority of the studied bacteria were lactose-negative, corresponding to the inability of reptiles producing lactose. The normal habitat of Salmonellae in reptiles and the high phylogenetic age of reptiles allows the hypothesis that salmonellae could have a similar old age as their host animals, because the ecological niche, i.e. the bowel of reptiles, has no changed for some hundred million years.     

Feeding of reptiles: practice and problems

Reptiles show a high degree of physiological adaptation to their habitates. The digestive tract is characteristic in herbi- or folivorous, omni-, ovi- and carnivorous species, mainly differing in the length and volume of small and large intestine. The specialization requires adequate feeding methods for captured reptiles, not only with regards to the composition of the diet, but also to the feeding techniques. The quantitative knowledge of energy and nutrient requirements is still incomplete and feeding experiments are urgently required. Energy demand for maintenance is considerably lower than in warm blooded species (around 50-60 kJ ME/kg BW0.75/d). Nutritional disorders are found mainly in herbivorous species, especially if unbalanced rations with only one or two feedstuffs are offered. Among nutrient deficiencies, concerning vitamins and minerals, overdosage of some nutrients is encountered occasionally, which may be detrimental especially in case of vitamin A and D.     

Development of the plerocercoid I of Ophiotaenia europaea in reptiles

The existence of a two-host life-cycle in ophiotaeniid proteocephalideans was tested experimentally using Ophiotaenia europaea as a model. Three species of reptiles, Natrix natrix, Natrix tessellata and Lacerta viridis, were fed with experimentally infected copepods containing a large number of infective plerocercoids I. A few plerocercoids, most of which were dead, corresponding morphologically to the plerocercoid II developmental stage of O. europaea, were found encysted in the intestinal wall of N. natrix (8 days p.i.), N. tessellata (5 and 150 days p.i.) and L. viridis (40 days p.i.), while no plerocercoids or adult worms were recovered from their intestines. The results indicate that the infective plerocercoid I of O. europaea cannot undergo further development when ingested directly by the final host (a reptile), and that environmental temperature stimuli cannot initiate a reverse plerocercoid migration to the gut followed by strobilization.     

Ageing and mammalian mitochondrial genetics

Pig mange was investigated serologically with ELISA using Chekit Sarcoptest. The test consists of a homogenized antigen of Sarcoptes scabiei var. vulpes. A total of 356 sows sera samples were collected from 16 mange free breeding units and 19 units with clinical manifestation of mange infestation. The specificity of the test was 99.34% and the mean sensitivity value was 62%. This test will allow in the future not only the rapid and certain diagnosis of pig mange but also the screening of the pig breeding units after eradication of the disease.     

Ageing and adrenal cortical function

Ageing is associated with changes in the secretion of adrenal cortical steroids. In the elderly, cortisol secretion increases after stimulation, while the secretion of dehydroepiandrosterone (DHEA) decreases. Each of these hormones influences the age-related processes of energy metabolism, fat depot distribution, immune function and neurodegeneration. In animals the effects of adrenal steroids are dramatic and easily measured. In humans the effects are more subtle. This review summarizes these actions and emphasizes the differences of dosages used in various experimental designs. It is concluded that adrenal hormones may play a significant role in human ageing, but research is hindered because the molecular pathways of DHEA action are not known.     

Asymmetrical testicular weights in mammals, birds, reptiles and amphibia

A case of fatal Legionella longbeachae infection following heart transplantation is described. Gram stains of respiratory secretions on day 17 posttransplant revealed leucocytes and gram-negative bacilli, but there was no growth on routine bacterial culture. Legionella longbeachae serogroup 1 was isolated from respiratory specimens, blood, and postmortem lung tissue. Legionella longbeachae is a common cause of legionellosis in Australia, and infection has been associated with exposure to potting mixes. Specific culture for Legionella spp. should be performed for any patient who develops pneumonia following organ transplantation.     

Lithium secretion in kidneys of amphibians and reptiles under hydrated conditions

Renal lithium transport was studied at different hydration levels in five species of anuran amphibians (Bufo bufo, B. danatensis, B. viridis, Rana ridibunda, and R. temporaria), two species of urodeles (Triturus vulgaris and T. cristatus) and four species of reptiles (lizards Eremias multiocellata, Lacerta vivipara, Trapelus sanguinolentus, and Teratoscincus scincus). Under dehydration conditions, Li+ was reabsorbed in the kidneys of amphibians ans reptiles, but to a lesser degree than in mammalian kidneys: the ratio of lithium clearance (CLi) to glomerular filtration rate (GFR)--fractional lithium excretion--in dehydrated animals was in the range 0.5-0.8. The transition to the hydrated state resulted in a cessation of net renal lithium reabsorption. Under condition of high hydration, all the animals studied, except for urodeles, showed net renal secretion of Li+, i.e., CLi exceeded GFR. The ratio CLi/GFR was 1.2-1.3 in hydrated anurans and 1.7-2.3 in hydrated lizards. In urodeles, this ratio was approximately unity. It is suggested that renal lithium secretion in hydrated amphibians and reptiles reflects fluid secretion in the proximal tubule, which is additional to the glomerular filtration mechanism of fluid delivery to nephron under water loading.     

GH169合金的DA处理

用热变形后的直接时效(DA处理)和标准热处理对比试验的方法,对DA处理在GH169合金中的实际应用进行了探讨。结果表明,DA处理确可提高合金的拉伸强度,并大幅度提高光滑持久寿命。但由于塑性指标的降低而导致缺口持久和周期持久寿命的降低,并使疲劳、蠕变交互作用的蠕变损伤加剧。其原因是可能DA处理过程中晶界δ相析出过少,晶界晶内强度配合不良,达不到强韧化的作用。同时指出晶粒细化,并在变形工艺中对位错组态进行控制,使δ相以合理的数量和形态析出,才能获得真正应用的DA GH169合金。     

Anesthesia in domestic animals (small mammals, psittacines and reptiles)

Kandang Kerbau Hospital saw 165 new cases of uterine cancers over the 4-year period from 1991 to 1994. The median age of presentation was 54.1 years and 10.9% of these cases occurred in those aged less than 40 years, unlike the corresponding figures of 61 years and less than 5%, respectively, which are often quoted for endometrial cancers in standard textbooks. Endometrioid adenocarcinoma was the commonest type of uterine cancer seen in our population (75.2%) as in other series. However, we had fewer cases of adenoacanthoma (1.4%) and adenosquamous carcinoma (1.4%) but more cases of uterine sarcoma (11.5%) than is usually reported. 6.7% of our patients had papillary serous adenocarcinoma and 3.0% had clear cell carcinoma. These 2 sub-types are associated with poorer prognosis and there is a need to increase awareness of their existence in our local population as their management differs from that for the usual endometrioid adenocarcinoma. We had fewer patients with stage I disease (53.3%) but more patients with stage III disease (22.4%). This is most likely due to the use of surgico-pathological staging currently as opposed to the clinical staging used previously which led to the under-staging of a proportion of patients.     

Study of Low-Carbon Pipe Steel Strain Ageing

Metallurgist - Strain aging of pipe steels 06G2FB and 07G2MFB with ferrite-pearlite and ferrite-bainite structures is investigated. It is established that a ferrite-bainite structure is more...