Tissue recovery

The involvement of 2inc compounds in transcription and translation may be important for ceUular/tissue recovery processes. 

Dicarboxymethyl chitosan and 6-oxychitin sodium salt, applied to femoral surgical defects for 3 weeks produced a good histoarchitectural order in the newly formed bone tissue. The spongious trabecular architecture was restored in the defect site. The association of the chitin derivatives with the osteoblasts seemed to be the best biomaterial in terms of bone tissue recovery [128]. 

Postmortem human brain tissue is obviously not subject to as rigorous control as experimental tissue from laboratory animals. As such much care needs to be taken when attempting in situ hybridization with human brain. In addition to the normal factors such as age and gender that need to be controlled with human samples, other factors, such as the immediate premortem state of the individual, the time taken for tissue recovery, and the storage conditions, must also be considered (for review, see Hynd et al., 2003). 

In an experimental investigation, four human subjects tolerated 0.57 ppm iodine vapor for 5 minutes without eye irritation but all experienced eye irritation in 2 minutes at 1.63 ppm. In patients exposed to air saturated with iodine vapor for 3-4 minutes for therapeutic purposes, there was brown staining of the corneal epithelium and subsequent spontaneous loss of the layer of tissue recovery occurred within 2-3 days. Iodine in crystalline form or in strong solutions is a severe skin irritant it is not easily removed from the skin, and the lesions resemble thermal burns with brown... 

Cyclicity of administration is vital in the use of 5-FU as a radiosensitizer. The concept of cyclical treatment has been well established in cancer chemotherapy and alien to classical radiation therapy (where it is termed split-course therapy). 5-FU radio-sensitizes tumor tissue as well as normal cells. However, this normal tissue radio-sensitizationis limited to the irradiated field. Suitable fractionation (i.e., cyclical therapy) can permit rapid normal tissue recovery (23). The results of infused 5-FU and radiation in head and neck cancer supports the principle that cyclical treatment with 5-FU does not suffer from the limitations apparent in split-course radiation treatments. 

Gardner CM, Jacques SL, Welch AJ. Fluorescence spectroscopy of tissue recovery of intrinsic fluorescence from measured fluorescence. Applied Optics 1996, 35, 1780-1792. 

Franke C, Brinker G, Pillekamp F, Hoehn M (2000) Probability of metabolic tissue recovery after thrombolytic treatment of experimental stroke a magnetic resonance spectroscopic imaging study in rat brain. J Cereb Blood Flow Metab 20 583-591... 

Modern inhalation anesthetics are nonexplosive agents that include the gas nitrous oxide as well as a number of volatile halogenated hydrocarbons. As a group, these agents decrease cerebrovascular resistance, resulting in increased perfusion of the brain. They cause bronchodilation and decrease minute ventilation. Their clinical potency cannot be predicted by their chemical structure, but potency does correlate with their solubility in lipid. The movement of these agents from the lungs to the different body compartments depends upon their solubility in blood and various tissues. Recovery from their effects is due to redistribution from the brain. 

J. R. Liver biopsy effects of biopsy needle caliber on bleeding and tissue recovery. Radiology 1997 204 101-104... 

Therapy Effect. The effect of thrombolytic therapy on metabolic changes was studied in rat brains submitted to thromboembolic stroke by a MRSI. Temporal changes in the cerebral methabolites lactate and N-acetylaspartate (NAA) were determined. In individual pixels, the probability of metabolic tissue recovery clearly declined with increasing lactate concentration before thrombolysis. 

Bourre JM, Durand G, Pascal G, Y ouyou A. Brain-cell and tissue recovery in rats made deficient in N-3 fatty-acids by alteration of dietary-fat. J Nutr 1989 119(1) 15-22. 

Not all cells in the cardiac conduction system rely on sodium influx for initial depolarization. Some tissues depolarize in response to a slower inward ionic current caused by calcium influx. These calcium-dependent tissues are found primarily in the SA and AV nodes (both L- and T-channels) and possess distinct conduction properties in comparison with the sodium-dependent fibers. Calcium-dependent cells generally have a less negative RMP (-40 to -60 mV) and a slower conduction velocity. Furthermore, in calcium-dependent tissues, recovery of excitability outlasts full repolarization, whereas in sodium-dependent tissues, recovery is prompt after repolarization. These two types of electrical fibers also differ dramatically in how drugs modify their conduction properties (see below). 

This chapter summarizes our experience with this approach and describes some of the critical parameters involved in the preparation of rat neural tissue for LCM, with particular emphasis on protocols applied to the Arcturus Autopix LCM. This instrument has been superceded by more recent models, which are now marketed and distributed by MDS Analytical Technologies (http // www.moleculardevices.com). The principles described here, however, are applicable to tissue preparation for most LCM instruments. We describe two basic protocols for the isolation of samples of rat brain, first from unstained microdissected regions, and second, from brain cells that express specific antigens identified by immunostaining. In addition, we compare the effects of different fixation conditions on tissue recovery and RNA content using real-time QPCR. 

As a first step toward optimizing Immuno-LCM with alcohol fixation, we compared four different alcohol treatments. Serial cryosections of rat hindbrain were fixed in ice-cold 100% methanol, 70% methanol, 100% ethanol, or 70% ethanol for 2 min. The slides were treated for 1 min in cold PBS followed by dehydration as described above. A comparison of the amount of tissue removed by the AutoPix after these different conditions suggests that the different fixations resulted in visibly different amounts of tissue removed from the sections. All, however, produce samples that are suitable for efficient cell picking (Fig. 3). It appears, though, that fixation in 70% alcohol produced better tissue recovery in this experiment. 

The effect of a topically applied dose of parathion, carbaryl, and thiodicarb on red blood cell cholinesterase activity in the rat was reviewed along with pharmacokinectic data developed on their percutaneous absorption. Parathion and thiodicarb inhibited 50% of the red cell cholinesterase activity at dose levels of 3.2 and 33 mg/kg of bw, while no inhibition was detected with carbaryl at dose levels as high as 417 mg/kg of w. Parathion and carbaryl were absorbed at 0.33 and 0.18 ug/hr/cm, while thiodicarb was absorbed at rates varying from 0.27 to 0.042 ug/hr/cm of skin. Skin loss and plasma elimination data were used to calculate the values. The topically applied pesticides slowly penetrated skin and were available for absorption into blood and redistribution to other tissues. Recovery data suggested that evaporative losses occurred during the course of the 5-day study. The pesticides may be removed from skin by washing, thus reducing the amount available for absorption. 

Bourre., J.M., Durand, G., Pascal, G., and Youyou, A. (1989) Brain Cell and Tissue Recovery in Rats Made Deficient in (n-3) Fatty Acids by Alteration of Dietary Fat, J. Nutr. 119,15-22. 

Temporal studies have shown that particular cytokines and chemokines are associated with acute or chronic phases of RA, while RRV studies in animals have shown that after severe macrophage associated muscle necrosis post infection, tissue recovery could be observed with a return to normal function, which correlated with the disappearance of monocyte/macrophages from the site of pathology. Therefore, as well as elucidating the role for chemokines in the disease phase of EPA and other infectious arthritidies, future challenges will also center on the function of chemokines and collaborating cytokines in the recovery from arthritic/myalgic disease post infection. 

Interestingly, it was demonstrated that biomaterials may modulate macrophage polarization and can actively direct the host response toward the implant, favoring tissue recovery [10] (Fig. 19.2). 

Figure 19.2 Microparticles implanted in the infarcted myocardium of a rat myocardial infarction model. The bioresorbable scaffold interacts with the host tissue, modulating macrophage polarization through the recruitment of antiinflammatory M2 macrophages and favoring tissue recovery. PLGA MP, poly(lactic-co-glycolic acid)-microparticle.

It is important to preserve the sense of early management of a chemical accident, which is always preferable. Elapsed time decreases the chances of tissue recovery. 

Dog weight, kg- Time after 32P injec- tion, hr. Organ weight, g- Phosphatide content at end of experiment, mg./lOO g. tissue Recovery of phosphatide as per cent of injected 32p per g. phosphatide ... 

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