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Histochemistry Protocol
Published in Maher Kurdi, Neuromuscular Pathology Made Easy, 2021
It is rare to see artifacts occurring in the prefixation stage. However, if the muscle piece is left at room temperature for a long period of time, autolysis may occur. The autolysis destructs the tissue spaces and may also desaturate DNA, in which case the oxidative enzymes would not function well. The most common artifacts occurring in the muscle tissue fixation stage are freezing artifacts. The freezing procedure follows organized steps in which any improper technical mishandling may cause major cellular damage. Freezing artifacts (Figure 7.3d) appear as Swiss cheese holes. They represent areas where ice crystals damage the tissue. This mechanism is caused by the osmotic damage derived from ice formation. However, if the samples are kept too moist before freezing, fluid accumulates in the sample and the fibers become disrupted and vacuolated. If there is a long delay before freezing, depletion of glycogen occurs, and this may misdiagnose some suspected metabolic diseases.
Brain swelling, raised intracranial pressure and hypoxia-related brain injury
Published in Helen Whitwell, Christopher Milroy, Daniel du Plessis, Forensic Neuropathology, 2021
Histologically, there is general tissue pallor, lysed red cells with stagnation and perineuronal vacuolation with neuronal pallor (Figure 12.17b). Tissue reaction is lacking. This may make interpretation of timing of injuries difficult. These changes take around 12 hours to develop, becoming more obvious with the passage of time (Black 1978). Bacterial overgrowth which is seen in post-mortem autolysis is usually not seen.
Assessment of Airway Smooth Muscle Growth and Division: In Vitro Studies
Published in Alastair G. Stewart, AIRWAY WALL REMODELLING in ASTHMA, 2020
Success in obtaining viable primary cultures of airway smooth muscle cells is critically dependent on two factors. These are the time elapsed from excision of the tissue to its culture and the care taken in dissection to obtain smooth muscle which is not contaminated by unwanted connective tissue, cartilage, or overlying epithelium and submucosa. Human tissue is available from heart–lung transplant recipients, at post-mortem,18,36 or at thoracotomy.17,29,35,38 Transplant tissue probably offers the best, but least accessible, source of human tissue since large amounts of sterile and relatively nonhypoxic smooth muscle can be obtained. The amount of tissue which can be obtained from thoracotomy, however, is often very limited and is usually only available immediately distal to the resection margin, where there is a risk of removing malignant or transformed tissue. Whether or not the patient has been exposed to radiotherapy during treatment should also be considered when obtaining tissue from the operating theatre for culture. Thoracotomy specimens do, however, offer an immediate and relatively frequent source of sterile and nonhypoxic tissue. Tissue obtained at post-mortem is often aseptically compromised and may not be available until 24 to 48 h after death. Significant autolysis occurs at this time. Given the correct conditions, however, human airway smooth muscle cells can be successfully cultured using tissue from any of these sources. 17,18,29,35,36,38
SMAD4 protein is decreased in the dorsolateral prefrontal and anterior cingulate cortices in schizophrenia
Published in The World Journal of Biological Psychiatry, 2021
Andrew S. Gibbons, Daniel Hoyer, Brian Dean
All human tissue was sourced through the Victorian Brain Bank Network, Florey Institute of Neuroscience and Mental Health. Approval for the study was granted by the Ethics Committee of the Victorian Institute of Forensic Medicine. For each subject, a case history review was completed using the Diagnostic Instrument for Brain Studies (DIBS) (Hill et al. 1996; Roberts et al. 1998) and a consensus diagnosis reached by two psychiatrists and a psychologist. To reduce the impact of autolysis, cadavers were refrigerated within 5 h and the brains were frozen to −70 °C within 30 min of autopsy (Ferrer et al. 2007). Post-mortem interval (PMI) was calculated from the time death to that of autopsy. Where death was not witnessed, time of death was taken as the midpoint between the subject being found and being last seen alive. Subjects, who were found dead more than 5 h since being witnessed alive, were excluded from the study. The pH of the CNS was measured as described previously (Kingsbury et al. 1995). Duration of illness (DOI) was taken as the time from first presentation with psychiatric symptoms to the time of death. The final recorded antipsychotic drug doses (FRADD) were recorded and standardised to chlorpromazine equivalents.
Post-mortem interval estimative through determination of catalase and Δ-aminolevulinate dehydratase activities in hepatic, renal, skeletal muscle and cerebral tissues of Swiss mice
Published in Biomarkers, 2019
Jaini J. Paltian, Caren A. R. da Fonseca, Mikaela P. Pinz, Cristiane Luchese, Ethel Antunes Wilhelm
In this study, the inhibition of the enzyme activity could be explained for several reasons. First, δ-ALA-D is a sulfhydryl enzyme extremely sensitive to oxidizing agents and oxidative stress, which act by inhibiting the enzyme activity (Farina et al.2003). Indeed, after death, the deprivation of oxygen in the cell, causing cell damage and consequently oxidative stress (Rock et al.1996, Buck and Hochachka 1993). Therefore, we suggest that the inhibition on the δ-ALA-D activity at different intervals of death could be due to oxidative stress caused by the deterioration process in the organs. This result is in accordance with the effect of different post-mortem times on the CAT activity. A second reason for the inhibitory effect on the δ-ALA-D activity is the processes of post-mortem decomposition by autolysis. This process is one of those involved in the post-mortem decomposition and consists of the rupture of the lysosomal membrane releasing autolytic enzymes of the pancreas, stomach and intestine that give initiate the process of autolysis, promoting the digestion of the organic part of the cell (Croce and Croce 2012). During this process, proteins, such as the enzymes, are broken down via enzymatic processes into proteoses, peptones, polypeptides and amino acids (Dekeirsschieter et al. 2009, Hoffman et al.2009). Moreover, in the present study, we did not perform the δ-ALA-D expression, but we can suggest that during post-mortem process occur a reduction in the enzyme expression, resulting in the inhibition on its activity.
Frequencies of Immune Cells in the Human Small Bowel During Normal Gestation and in Necrotizing Enterocolitis
Published in Fetal and Pediatric Pathology, 2019
Paul Peterslund, Lene Rasmussen, Niels Qvist, Tine Plato Hansen, Steffen Husby, Sönke Detlefsen
For retrieval of USB cases, a “Patobank” search was performed as described above, but also including all small bowel specimens with inflammatory diseases (SNOMED criteria: Topography Starts: “T64*” OR “T65*” AND Diagnosis remark = “P30620” AND Diagnosis code = “M4*” AND age <1 (SNOMED, 4th edition, 2008)). A total of 178 patients were identified and further evaluated. Exclusion criteria were: lack of NEC diagnosis, diagnosis of cystic fibrosis, IUGR/small for GA, operation >1 week after birth and non-availability of ileal or jejunal tissue, which reduced the number of evaluable specimens to 19. Grade of autolysis was evaluated as described above, leading to the exclusion of 10 patients. One case was included in another research project, resulting in a total of 8 included patients. The GA ranged from 24 to 32 weeks.