Mammals indicators

A survey of glucokinase activity in different muscles from different mammals indicates a variation in specific activity. Thus, in the rabbit the sequence of glucokinase activity is heart muscle > skeletal muscle > stomach muscle > diaphragm muscle, the ratio of activities being 1 1.5 0.5 O.2. In the rat the ratio of heart to skeletal muscle activity is 1.4 in the guinea pig, 1.6 and in the chicken, 1.9. Extracts of skeletal muscle of rat and man are significantly more active than those obtained from similar muscles of the guinea pig, rabbit, and chicken. 

The toxicity of the tetraorganotins has beenUtde studied. Available Hterature indicates that tetrabutyltin and the higher tetraalkyltins are substantially less toxic than triorganotins to mammals if taken orally (175). The high toxicity reported for tetraethyltin (LD g = 9 16 mg/kg) appears to be caused by its rapid conversion in the Hver to a triethyl tin species. 

The importance of the penicillins as a class of heterocyclic compounds derives primarily from their effectiveness in the treatment of bacterial infections in mammals (especially humans). It has been estimated that, in 1980, the worldwide production of antibiotics was 25 000 tons and, of this, approximately 17 000 tons were penicillins (81MI51103). The Food and Drug Administration has estimated that, in 1979 in the U.S.A., 30.1 x 10 prescriptions of penicillin V and 44.3 x 10 prescriptions of ampicillin/amoxicillin were dispensed. This level of usage indicates that, compared to other methods of dealing with bacterial infection, the cost-benefit properties of penicillin therapy are particularly favorable. Stated differently, penicillin treatment leads to the elimination of the pathogen in a relatively high percentage of cases of bacterial infection at a relatively low cost to the patient in terms of toxic reactions and financial resources. 

Peters s results for corycavine and corycavamine indicate that these two alkaloids produce narcosis in frogs followed by paralysis of the spinal cord, and in mammals increased secretion of tears and saliva and epileptiform convulsions without increase of reflex irritability they also adversely affect the heart. ... 

P-Homochelidonine was examined by Meyer and von Engel, and the results, as quoted by Sehmidt, indicate that in frogs -homoehelidonine behaves like ehelidonine, and that in mammals it eauses slight nareosis and a transitory fall in blood pressme, followed by eonvulsions of the type indueed by camphor, slowing of the pulse and, in large doses, paralysis of the vaso-motor centres. It also paralyses the ends of the sensory nerves. ... 

The organotins covered in this assessment have low acute toxicity to laboratory mammals, with most studies indicating LD50S above 100 mg/kg body weight, and many above 1000 mg/kg body weight. 

Table 4.1. Bone 5 C n, 5 C ,b, AS C rb-coii, S N ii values of recent mammals from Europe, Siberia, and northwestern North America. died before 1880 died or was killed in the field during the last ten years. Values previously published have been indicated in the last column (Ret.) as follows 1 = and 5 N an published...

These data show that both models identify important variables that affect 5 Obody w.ier and 8 Ophospha in mammals. Both serve to identify the dikdik as an outlier which may be explained by their sedentary daytime pattern. On the other hand, the body-size model (Bryant and Froelich 1995), which may reliably predict animal 5 0 in temperate, well-watered regions, does not predict 8 Opho,phaw in these desert-adapted species. The second model (Kohn 1996), by emphasizing animal physiology independent of body size, serves to identify species with different sensitivities to climatic parameters. This, in conjunction with considerations of behavior, indicate that certain species are probably not useful for monitoring paleotemperature because their 5 Obodyw er is not tied, in a consistent way, to The oryx, for example, can... 

FIGU RE 2.10 Plasma A-esterase activities of birds and mammals. Activities were originally measured as nanomoles product per milliliter of serum per minute, but they have been converted to relative activities (male rat = 1) and plotted on a log scale. Each point represents a mean value for a single species. Substrates , paraoxon , pirimiphos-methyl oxon. Vertical hues indicate limits of detection, and all points plotted to the left of them are for species in which no activity was detected. (Activities in the male rat were 61 4 and 2020 130 for paraoxon and pirimiphos-methyl oxon, respectively.) (From Walker 1994a in Hodgson and Levi 1994.)... 

There have been a nnmber of estimates of bioconcentration factors for total PCBs in aqnatic species following long-term exposure to PCB mixtures (EHC 140). Values for both invertebrates and hsh have been extremely variable, ranging from values below 1 to many thonsands. Bioaccnmnlation factors for birds and mammals for different Aroclors have indicated only limited degrees of bioaccumulation from food, for example, 6.6 and 14.8 for the whole carcasses of big brown bats Eptesicus fuscus) and white pelican (Pelecanus erythrorhynchos), respectively (see Environmental Health Criteria 140). 

Phosphatidylcholine, commonly known as lecithin, is the most commonly occurring in natnre and consists of two fatty add moieties in each molecule. Phosphati-dylethanolamine, also known as cephahn, consists of an amine gronp that can be methylated to form other compounds. This is also one of the abundant phospholipids of animal, plant, and microbial origin. Phosphatidylserine, which has weakly acidic properties and is found in the brain tissues of mammals, is found in small amounts in microorganisms. Recent health claims indicate that phosphatidylserine can be used as a brain food for early Alzheimer s disease patients and for patients with cognitive dysfunctions. Lysophospholipids consist of only one fatty acid moiety attached either to sn-1 or sn-2 position in each molecule, and some of them are quite soluble in water. Lysophosphatidylchohne, lysophosphatidylserine, and lysophos-phatidylethanolamine are found in animal tissues in trace amounts, and they are mainly hydrolytic products of phospholipids. 

The dietary importance of benthic invertebrates to many species of fish, birds, and mammals (Vander Zanden and Vadeboncoenr 2002) signifies their importance in the trophic transfer of MeHg and their potential relevance as biological indicators. Some benthic invertebrates (e g., oysters, clams, shrimp, crabs, and crayfish) are consumed by humans, providing a direct pathway for exposure to MeHg. In the United States, shellfish rank below fish as a source of dietary MeHg in the human population (NRC 2000 Schober et al. 2003). 

---