Laboratory investigation

Hepatitis describes infiltration of the hepatic tissue by mononuclear cells, which may or may not be associated with hepatocellular changes. There are also different patterns of cellular injury, such as those affecting the hepatocellular organelles— particularly, the microsomes, peroxisomes, and mitochondria. When hepatocellular injury occurs, the aminotransferases are probably the most useful markers, and they may be supplemented by measurements of other plasma enzymes—ALP, GLDH, and plasma bilirubin (see the following sections on laboratory investigations). Several markers of cellular function require tissues for the measurements of altered function (e.g., microsomal cytochrome P450 measurements). 

Some of the causes of hepatotoxicity outlined by Lee (2003) include covalent binding of xenobiotics mediated by cytochrome P450s alterations of mitochondrial function affecting beta-oxidation of fatty acids  

T-lymphocyte activation and cytolysis and alpha-tumor necrosis factor stimulation of apoptosis. 

Effects on hepatic protein synthesis are caused by many hepatotoxins, but the changes may take some time to become apparent given the half-lives of the involved proteins. Reductions of plasma albumin and acid glycoprotein may affect the binding and exposures to xenobiotics and plasma bilirubin. Other effects on proteins may also be due to reduced food intake due to toxicity. The production of many plasma proteins, including those involved in complement and coagulation cascades, can be affected by reductions of hepatic protein synthesis. 

The hepatic mitochondria help to preserve cellular integrity by regulating oxidative phosphorylation and the redox potential. There are a number of toxic effects on mitochondria, including the inhibition of DNA synthesis production of reactive 

Lethal and sublethal effects of chlorpyrifos under controlled conditions are summarized for selected species of aquatic invertebrates and vertebrates, and for representative species of birds, and mammals. 

Sublethal effects of chlorpyrifos exposure have been documented for many species of freshwater and marine fauna they include inhibition of cholinesterase (ChE) activity levels in brain and hematopoietic organs, reduction in blood glucose levels, sluggishness, motor incoordination, delayed maturation and growth, renal histopathology, reproductive impairment, and reduced feed intake. Reproductive impairment, for example, was observed in Daphnia magna at 0.08 p,g chlorpyrifos/L. Reduction in settling rate was shown in oyster 

---

Pentoxifylline is stmcturaHy related to other methylxanthine derivatives such as caffeine [58-02-2] (1,3,7-trimethylxanthine), theobromine [83-67-0] (3,7-dimethylxanthine), and theophylline [58-55-9] (3,7-dihydro-1,3-dimethyl-1 H-piirine-2,6-dione or 1,3-dimethylxanthine), which also show radioprotective activity in some instances, suggesting that methylxanthines as a dmg class may radioprotect through a common mechanism (see Alkaloids). In a retrospective analysis of cervical and endometrial cancer patients receiving primary or adjuvant XRT, no association between caffeine consumption and incidence of acute radiation effects has been found. However, there was a decreased incidence of severe late radiation injury in cervical cancer patients who consumed higher levels of caffeine at the time of thek XRT (121). The observed lack of correlation between caffeine consumption and acute radiation effects is consistent with laboratory investigations using pentoxifylline. 

Laboratory investigations may possibly establish reaction mechanisms, but quantitative data for design purposes require pilot plant work with equipment of the type expected to be used in the plant. 

The second level of interaction, the intermediate-dose level, can result in measurable effects on forest ecosystems. These effects consist of a reduction in forest growth, change in forest species, and susceptibility to forest pests. Both laboratory investigations and field studies show SO2 to be an inhibitor of forest growth. When various saplings have been exposed to SO2 in the laboratory, they show reduction in growth compared with unexposed... 

ISO EN 9886 presents the principles, methods, and interpretation of measurements of relevant human physiological responses to hot, moderate, and cold environments. The standard can be used independently or to complement other standards. Four physiological measures are considered body core temperature, skin temperature, heart rate, and body mass loss. Comments are also provided on the technical requirements, relevance, convenience, annoyance to the subject, and cost of each of the physiological measurements. The use of ISO 9886 is mainly for extreme cases, where individuals are exposed to severe environments, or in laboratory investigations into the influence of the thermal environment on humans. 

The relaxation time r of the mean length, = 2A Loo, gives a measure of the microscopic breaking rate k. In Fig. 16 the relaxation of the average length (L) with time after a quench from initial temperature Lq = 1.0 to a series of lower temperatures (those shown on the plot are = 0.35,0.37, and 0.40) is compared to the analytical result, Eq. (24). Despite some statistical fluctuations at late times after the quench it is evident from Fig. 16 that predictions (Eq. (24)) and measurements practically coincide. In the inset is also shown the reverse L-jump from Tq = 0.35 to = 1.00. Clearly, the relaxation in this case is much ( 20 times) faster and is also well reproduced by the non-exponential law, Eq. (24). In the absence of laboratory investigations so far, this appears the only unambiguous confirmation for the nonlinear relaxation of GM after a T-quench. 

Hakansson, B., Yontchev, E., Vannberg, N.-G. and Hedegard, B. An Examination of the Surface Corrosion State of Dental Fillings and Constructions. 1. A Laboratory Investigation of the Corrosion Behaviour of Dental Alloys in Natural Saliva and Saline Solutions , Journal of Oral Rehabilitation, 13, 235-246 (1986)... 

Meat Products. Laboratory investigations as well as practical experience have shown that aluminum containers do not cause the objectionable darkening of meat that occurs with other metals. Wunsche (13) found that luncheon meat stored in lacquered aluminum cans retained its normal color after more than one year, while a slight surface discoloration was observed on the same product packed in lacquered tinplate cans. 

As an aid in laboratory investigations ether carboxylic acids have been used as chlorophyll solubilizers [234,235] and as dispersing agents for thermochromic compounds to be used as temperature indicators [236]. 

If the reagent is intended for an earlier stage laboratory investigation, then the label should state For Research Use Only. Not for use in diagnostic procedures. ... 

This is an important consideration in the selection of an optimum polymerization diluent, which is very easily neglected in laboratory investigations. Also, since little is known cd>out particle coalescence in the presence of mechanical agitation, extreme care must be taken in mixing scale-up. 

Recent work in the authors laboratory investigated the effects of the molar ratio and the reactive conditions on the elasticity, strength, biodegradation, and thermal processing abilities. The different... 

Yunginger JW, Nelson DR, Squillace DL, Jones RT, 21 Holley KE, Hyma BA, Biedrzycki L, Sweeney KG, Stumer WQ, Schwartz LB Laboratory investigation of deaths due to anaphylaxis. J Forensic Sci 1991 36 857-865. 

The mucopolysaccharidoses share a common mechanism of causation, as illustrated in Figure 48-10. They are inherited in an autosomal recessive manner, with Hurler and Hunter syndromes being perhaps the most widely studied. None are common. In some cases, a family history of a mucopolysaccharidosis is obtained. Specific laboratory investigations of help in their diagnosis are urine testing for the presence of increased... 

Laboratory investigations that aid in the diagnosis of hemolytic anemia are listed in Table 52-7. 

To study the effects of molecular diffusion and formation/destabilization of reaction fronts it is advised to rely on small flow-through chambers such as capillaries or cells of sheet-type cross-section [68]. These micro reactors simply provide the small-scale environment needed for such laboratory investigations. 

Since then, numerous industrial laboratory investigations have been carried out [71]. 

Freedom in process design is greatest at this stage of development, while the cost of error elimination is smallest (see Fig 5.2-3). Therefore, downscaling and extension of laboratory investigations in later phases of development is common practice. Compared to large-scale studies, laboratory work is less expensive by orders of magnitude and less sensitive to mistakes. 

The very basis of the kinetic model is the reaction network, i.e. the stoichiometry of the system. Identification of the reaction network for complex systems may require extensive laboratory investigation. Although complex stoichiometric models, describing elementary steps in detail, are the most appropriate for kinetic modelling, the development of such models is time-consuming and may prove uneconomical. Moreover, in fine chemicals manufacture, very often some components cannot be analysed or not with sufficient accuracy. In most cases, only data for key reactants, major products and some by-products are available. Some components of the reaction mixture must be lumped into pseudocomponents, sometimes with an ill-defined chemical formula. Obviously, methods are needed that allow the development of simple... 

E. A. Morris, III and D. H. Pope. Field and laboratory investigations into the persistence of glutaraldehyde and acrolein in natural gas storage operations. In Proceedings Volume. 49th Annu NACE Int Corrosion Conf (Corrosion 94) (Baltimore, MD, 2/27-3/4), 1994. 

I. S. Nashawi. Laboratory investigation of the effect of brine composition on polymer solutions Pt 2 Xanthan gum (XG) case. SPE Unsolicited Paper, SPE-23534, United Arab Emirates Univ, August 1991. 

Verification implies that the laboratory investigates trueness and precision in particular. Elements which should be included in a full validation of an analytical method are specificity, calibration curve, precision between laboratories and/or precision within laboratories, trueness, measuring range, LOD, LOQ, robustness and sensitivity. The numbers of analyses required by the NMKL standard and the criteria for the adoption of quantitative methods are summarized in Table 10. 

Limited value. Laboratory investigation is of limited value and should be pursued only in context of other history or physical examination findings. 

Twiss, M., Errecalde, O., Fortin, C., Campbell, P., Jumarie, C., Denizeau, F., Berkelaar, E., Hale, B., and van Rees, K., Coupling the use of computer chemical speciation models and culture techniques in laboratory investigations of trace metal toxicity, Chem Spec Bioavailab, 13 (1), 9-24, 2001. 

Below 200°C, reliable urea thermohydrolysis is very hard to achieve, therefore urea dosage is usually stopped in real-world urea-SCR systems in this temperature regime. Another serious problem connected with the urea injection at low temperatures is the formation of white to yellowish deposits, which are observed when urea solution is injected at very low exhaust gas temperatures or if the urea spray forms a thick film at the walls of the SCR system. The analysis of these deposits [26] showed that they mainly consist of urea and some biuret at low temperatures and of cyanuric acid and some biuret at higher exhaust gas temperatures around 350°C. From laboratory investigations of the urea decomposition, it is known that biuret is easily formed from 150 to 190°C [27], whereas the formation of cyanuric acid is predominant from 200 to 300°C, according to the following reactions [12] ... 

Rajanikanth, B.S., Srinivasan, A.D. and Ravi, V. (2005) Discharge plasma treatment for NOx reduction from diesel engine exhaust A laboratory investigation, IEEE Trans. Diel. El. Insul. 12, 72-80. 

---