Neurohistology
Burkhard Madea in Asphyxiation, Suffocation,and Neck Pressure Deaths, 2020
After prolonged survival, the cellular response may be absent in rare cases. This can occur if the asphyxiation process has led to a severe or even complete interruption of the cerebral blood flow for a few minutes. A reperfusion after this trauma is then no longer possible, due to the immediately developing oedema with rising cerebral pressure. The cerebral pressure can rise higher than the systolic blood pressure in a short period of time. This leads to a total ischaemic infarction of the brain. Even if the affected person receives intensive medical care for hours or even days until the diagnosis of brain death has been completed, physiological cellular reactions in the brain are no longer possible. Microscopically, necrosis of not only the nerve cells but also of all other cells is found. The release of lysosomal enzymes leads to the general autolysis of all brain structures. Such an event was also referred to as ‘intravital autolysis’. In normothermal conditions, an extensive ‘intravital brain autolysis’ manifests within 24−48 hours. The brain becomes generally soft. Necrotic pressure cones develop at the cerebellar tonsils. The autolytic brain can show a demarcation of the pituitary gland, optic nerve and medulla oblongata [1].
Assessment of Airway Smooth Muscle Growth and Division: In Vitro Studies
Alastair G. Stewart in 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
Histochemistry Protocol
Maher Kurdi in 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.
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.
Yeast-inspired drug delivery: biotechnology meets bioengineering and synthetic biology
Published in Expert Opinion on Drug Delivery, 2019
Chinnu Sabu, Panakkal Mufeedha, Kannissery Pramod
The microbial disruption method is mainly classified into two types: mechanical and nonmechanical methods [37]. The mechanical method of disruption is based on shear force such as bead milling, sonication, etc. can be classified as solid shear and liquid shear method. Nonmechanical methods are further classified into three types: physical, chemical, and enzymatic methods (Figure 3) [36]. The efficiency of different disruption method is evaluated by direct microscopic and indirect methods. Autolysis does not destroy the cell wall but helps release the intracellular components from the cell [36]. It has been observed that yeast cell wall disruption is often difficult as it limits the access of solvents to enter the cell. The factor affecting the efficiency of the method includes speed of method, cost, ease of extraction, and product stability.
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
A “Patobank” search using SNOMED criteria identified consecutively registered autopsies performed on fetuses and perinatal deaths in the Region of Southern Denmark between 01 January 2008 and 31 December 2012. The SNOMED criteria were: “T89*” combined with “F35330” and/or “P30140.” A total of 402 autopsies were identified, and the autopsy reports were further evaluated. Exclusion criteria were: small intestine not described microscopically as either “well preserved” or “relatively well preserved,” intrauterine infection, intrauterine growth restriction (IUGR), survival >1 week postpartum or divergence in clinically and autopsy-assessed GA. The autopsy-assessed GA was defined as the 5–95 percentiles of crown-rump, crown-heel and foot-plate lengths [14]. On this basis, a total of 289 autopsies were excluded. Of the remaining 113 cases, the grade of autolysis was evaluated on H&E-stained slides. Autolysis was considered excessive if tissue did not contain areas of mucosa with orthogonally cut cell-rich villi with a well-defined epithelial lining. The grade of autolysis was evaluated by the trained investigator (PP) and in uncertain cases, reviewed by a specialist in gastrointestinal pathology (SD or TPH). In total, NSB specimens from 23 autopsies were included. The GA ranged from 12 to 27 weeks.
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