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At least 235 records · Page 13Linked to original sources
PubMed1997

Increased stability of PEG-PPG conjugated human urokinase against autolysis.

Human urokinase (UK) was easily degraded during the incubation at 37 degrees C in a time-dependent manner. The degradation was also observed in the presence of trypsin inhibitors, suggesting that UK was not degraded by exogeneous trypsin-like serine protease but by autolysis. In this cases, the A-chain of UK was selectively degraded. Polyethylene glycol-polypropylene glycol conjugated urokinase (PEG-PPG-UK) was not degraded after prolonged incubation at 37 degrees C. These results demonstrated that PEG-PPG modification completely blocked the degradation of UK by autolysis.

Autolysis↗
PubMed2001

Human micro-calpain: simple isolation from erythrocytes and characterization of autolysis fragments.

Heterodimeric p-calpain, consisting of the large (80 kDa) and the small (30 kDa) subunit, was isolated and purified from human erythrocytes by a highly reproducible four-step purification procedure. Obtained material is more than 95% pure and has a specific activity of 6-7 mU/mg. Presence of contaminating proteins could not be detected by HPLC and sequence analysis. During storage at -80 degrees C the enzyme remains fully activatable by Ca2+, although the small subunit is partially processed to a 22 kDa fragment. This novel autolysis product of the small subunit starts with the sequence 60RILG and is further processed to the known 18 kDa fragment. Active forms and typical transient and stable autolysis products of the large subunit were identified by protein sequencing. In casein-zymograms only the activatable forms 80 kDa+30 kDa, 80 kDa+22 kDa and 80 kDa+18 kDa displayed caseinolysis.

Autolysis↗
PubMed1995

Auditory brainstem response and temporal bone and brainstem pathology in brainstem death, with special reference to autolysis of red blood cells.

We studied the pathological changes in the temporal bone and brainstem, with particular attention to the autolysis of red blood cells in and around the blood vessels, in six cases of brainstem death determined by auditory brainstem responses (ABRs). Our findings showed that the cochlea, the visceral organs and the spinal cord below a certain level of the cervical segments continued to live after brainstem death. Red blood cells in the vessels of the brainstem and cerebellum exhibited severe autolysis, whereas most red blood cells in the cochlea were preserved. Our findings of autolytic changes in red blood cells in the brainstem, and the preservation of red blood cells in the cochlea, imply initial loss of brainstem function and delayed loss of cochlear function after prolonged absence of ABRs.

Adolescent↗
PubMed2000

The autolysis loop of activated protein C interacts with factor Va and differentiates between the Arg506 and Arg306 cleavage sites.

The anticoagulant human plasma serine protease, activated protein C (APC), inactivates blood coagulation factors Va (FVa) and VIIIa. The so-called autolysis loop of APC (residues 301-316, equivalent to chymotrypsin [CHT] residues 142-153) has been hypothesized to bind FVa. In this study, site-directed mutagenesis was used to probe the role of the charged residues in this loop in interactions between APC and FVa. Residues Arg306 (147 CHT), Glu307, Lys308, Glu309, Lys311, Arg312, and Arg314 were each individually, or in selected combinations, mutated to Ala. The purified recombinant protein C mutants were characterized using activated partial thromboplastin time (APTT) clotting assays and FVa inactivation assays. Mutants 306A, 308A, 311A, 312A, and 314A had mildly reduced anticoagulant activity. Based on FVa inactivation assays and APTT assays using purified Gln506-FVa and plasma containing Gln506-FV, it appeared that these mutants were primarily impaired for cleavage of FVa at Arg506. Studies of the quadruple APC mutant (306A, 311A, 312A, and 314A) suggested that the autolysis loop provides for up to 15-fold discrimination of the Arg506 cleavage site relative to the Arg306 cleavage site. This study shows that the loop on APC of residues 306 to 314 defines an FVa binding site and accounts for much of the difference in cleavage rates at the 2 major cleavage sites in FVa. (Blood. 2000;96:585-593)

Arginine↗
PubMed2001

[Effect of autolysis on histochemical examinations of the central nervous system].

The objective of the study was to explain the effect of autolysis on immunohistochemical detection of neurone-specific enolase (NSE), beta-amyloid protein precursor (beta-APP) and ubiquitine in cerebral tissue. The examination was made in 6 deceased subjects without mechanical injury of the CNS and 6 subjects with a craniocerebral injury who survived from 6 hours to 3 days. In all deceased subjects the post-mortem examination was made within 24 hours after death. For immunohistochemical examination tissue excisions were taken from standard sites of the brain. The first tissue excisions were immersed into 10% formol after a post-mortem interval of 24 hours. The remaining tissue slices were subjected to autolysis at room temperature and gradually immersed into formol after 24-hour intervals, the longest post-mortem interval being 168 hours, i.e. 7 days. For visualization of the linked primary antibody the biotin-streptavidin system labelled with alkaline phosphatase was selected. In the group of 6 subjects who died after a craniocerebral injury in 4 instances axonal lesions were detected, i.e. axonal oedema or formation of retraction spheroids. The damaged axons were positive on examination with all investigated antibodies, whereby it was possible even after a 168-hour post-mortem interval to differentiate damaged and not damaged axons. In the group of 6 subjects without mechanical injury of the CNS in 5 instances axonal oedema was found, however, it was not positive with anti-NSE antibodies nor with anti-beta-APP. After the 24-hour post-mortem interval in this group in 3 instances ubiquitine positivity was found in axons but already after a post-mortem interval exceeding 2 days the axons were ubiquitine positive in all 6 subjects. Lumpy deposits of this substance could be detected in axons also beyond axonal structures.

Adolescent↗
PubMed1975

[Investigation of the state of the cell membrane and the mechanism of autolysis of the cornea in the process of conservation (author's transl)].

Questions of the mechanism of autolysis of the corneal tissue were examined on 72 dog eye balls, which had been kept in a damp chamber for 3 hours, 2 days and 15 days. The method of chemoluminescence found especial importance here, because it made possible to analyse the state of the functioning cell membrane and to gain information of bio-energetic processes which take place in the lipoprotein complexes of the cells and their organelles in the corneal tissue. From the results obtained it can be assumed, that in the mechanisme of autolysis disturbances of the self-regulating oxidation of the lipoidstructure-elements are of great importance in the process of survival and the conservation of corneal tissue.

Animals↗
PubMed1976

Sequential sterile autolysis in the ovine fetus: macroscopic changes.

Sterile intrauterine autolysis was experimentally produced in 28 ovine fetuses in the last 3rd of gestation by umbilical artery ligation. The fetuses were retrieved by cesarean section after periods of sterile intrauterine autolysis ranging from 0.5 to 168 hours. The following autolytic changes, frequently reported as significant lesions in infectious abortions in cattle and sheep, were observed: subcutaneous blood-tinged gelatinous edema, blood-tinged fluid in the serous cavities, renal cortical softening, uniform reddish brown tissues, hepatic friability and mottling, and cloudy yellow to cloudy red abomasal contents. The appearance of these and other autolytic changes corresponded to sterile sequential autolytic changes reported in the rabbit fetus and used to determine duration of retention of stillborn infants and are of comparative biomedical significance. The sequential autolytic changes may be used as an index to duration of retention after death of a ruminant fetus and provide a basis for reappraising various infective abortifacients common to ruminants by allowing separation of specific lesions from strictly autolytic changes.

Abomasum↗
PubMed2003

Association of mitochondrial calpain activation with increased expression and autolysis of calpain small subunit in an early stage of apoptosis.

Various stimuli including anticancer drugs are capable of initiating the apoptotic death program in human tumor cells via activation of caspases. Mitochondria play an essential role for cell apoptotic commitment. Previous studies have shown a potential role of calpain activation in apoptosis, however, the involved molecular mechanisms remain to be defined. In the current study, we have examined the expression and activation of mitochondrial calpain in Jurkat T leukemia cells, MCF-7 breast carcinoma and LNCaP prostate cancer cells during apoptosis induced by an anticancer drug (VP-16, tamoxifen) or the specific p38 kinase inhibitor PD-169316. Our results suggest that increased expression and autolysis of the mitochondrial calpain small subunit are tightly associated with calpain activation in an early stage of apoptosis. In contrast, there were no correlations observed between the early calpain activation and changes in levels of mitochondrial calpain large subunit and the endogenous calpain inhibitor calpastatin. Furthermore, pretreatment with the specific pharmacological calpain inhibitor calpeptin blocked the drug-induced calpain small subunit autolysis and calpain activation in mitochondria and inhibited apoptosis-associated caspase-3 activation, demonstrating that mitochondrial calpain activation through small subunit cleavage is an essential step for inducing tumor cell apoptosis by various anticancer drugs.

Antineoplastic Agents↗
PubMed1975

The prevention of autolysis of stored cornea using steroid as a lysosome membrane stabilizer.

Many eyes donated for use in corneal grafting are rejected because of signs of autolysis in the donor material. The purpose of this experimental study was to determine whether hydrocortisone acting as a lysosome membrane stabilizer could prevent or retard autolysis of the corneas under storage, and if so, what was the most efficacious concentration. Different groups of rabbit corneas were placed in saline as controls or in varying concentrations of hydrocortisone (10(-10) M to 10(-4) M at pH 7.4) at 37 degrees C and 4 degrees C. Acid phosphatase released after six hours was measured biochemically. This enzyme was used as a marker enzyme reflecting lysosomal labilization. Results showed a significant stabilization of the lysosomal membrane at 4 degrees C as compared to 37 degrees C. A trend towards stabilization of the lysosomal membrane was seen when 10(-8) M concentration of hydrocortisone at 37 degrees C was used, there being no demonstrable stabilization at 4 degrees C.

Acid Phosphatase↗
PubMedDate not supplied

[Changes in rat skeletal muscle actin during postmortem autolysis].

Electrophoretic analysis of actin, obtained within 1.2 and 5 days after death, did not exhibit any destructions of the protein. At the same time, an ability of actin to develop the actomyosin complex was decreased during autolysis as shown by affinity chromatography of actin on CNBr-Sepharose containing immobilized myosin. Alterations in fluorescence spectra of the actin preparations enabled to suggest that an increase of inactive, unable to polymerization form of the protein during autolysis was responsible for reduction of its property to associate with myosin.

Actins↗
PubMed1989

[The effect of autolysis on the conduction system in young rats. An enzyme histochemistry study].

The conducting system of young rats was studied by histochemistry during autolysis at room temperature lasting 1, 3, 6, 24 and 48 hours. The results were compared with working muscle tissue. The most sensitive was the "glycogen-dependent" phosphorylase and the activity decreased after 1 hour. It was slightly detectable as late as after 24 hours when the working muscle was already negative. Other enzyme activities (oxidoreductases and hydrolases) were practically uninfluenced by 6 hour autolysis. A substantial decrease of activities was found in conducting system after 48 hours in comparison to the working muscle. A solitary relatively strong residual activity belonged to acetylcholine-esterase in the conducting system. Detection of acetylcholine-esterase can be useful in identification of the conducting system even later after death.

Animals↗
PubMed1988

[Ultrastructure of neurohypophysis during autolysis].

Autolysis was studied in neurohypophyseal secretory cells by electron microscopy at 30 min, 1-h, 3-h and 6-h intervals. In the first 30 minutes after decapitation mitochondrial slougness phenomenon was observed. "Mosaic" autolytic changes in the ultrastructure of neurohypophyseal cells were found. Severe destructive processes were clearly observed in neurohypophyseal cells when autolysis was continued for 6 hours.

Animals↗
PubMed1977

The prevention of autolysis in stored corneas by lysosome stabilization. A histochemical study.

We wished to determine if dexamethasome, acting as a lysosome stabilizer, could reduce the release and activation of the lysosomal acid hydrolases, and thus retard autolysis of stored corneas. One cornea (experimental) of a rabbit was soaked in a 2 per cent steroid solution and the other cornea (control) in physiological saline for 3 hours at 23 degrees C. The experimental and control corneas were then processed histochemically to show the localization of the lysosomal marker enzymes beta-glucuronidase and acid phosphatase. Compared to the controls the steroid treated corneas showed reduced enzyme activity suggesting that autolysis during storage had been retarded.

Acid Phosphatase↗
PubMed1987

Effect of synthetic metalloprotease inhibitors on cartilage autolysis in vitro.

The role of chondrocyte metalloprotease (CMP) in mediating cartilage autolysis was studied. Proteoglycan (PG) release and synthesis by rabbit articular cartilage explants were measured. After a 1-day preculture in control medium, 3.3 X 10(-6) M retinoic acid (RET) treatment for 1 day stimulated PG release several fold. RET also caused a large decrease in PG synthesis that returned to the control level after a 3-day recovery period. The effect on PG synthesis was observed at serum levels of 5 and 0.05%. The effect of RET on PG release required protein synthesis, inasmuch as it was lost in cultures maintained in media without amino acids or in a low volume of media. Interleukin-1 (IL-1) and lipopolysaccharide (LPS) treatment for 2 days also stimulated PG release. More PG was released after RET than after IL-1 or LPS, and only RET produced an effect that was evident by day 1. The amount of CMP that produced the same size effect on PG release as these stimulators was below the detection level of PG protease assays. Three potent CMP inhibitors reduced RET-, IL-1- and LPS-stimulated PG release to control levels. These inhibitors did not block another action of RET on chondrocytes, namely the inhibition of PG synthesis by RET immediately after treatment. The inhibitors did not act by reducing cell viability, because recovery of the rate of PG synthesis 3 days post-treatment occurred in inhibitor-treated cultures. These studies suggest that CMP is involved in cartilage autolysis that is stimulated by RET and IL-1.

Animals↗
PubMed1987

Rapid postmortem gut autolysis in infant rats: a potential problem for investigators.

Experiments were designed to determine the rate and nature of postmortem autolysis in the gut of neonatal rats, as necessary baseline information for developing a model of human neonatal necrotizing enterocolitis. We studied 60 animals, including 33 Wistar rats, 18 Sprague-Dawley rats and nine CD-1 mice. The variables examined included age of the animals (2 or 14 days) and length of delay and holding temperature (20 degrees C or 37 degrees C) after sacrifice. At necropsy, bowel was rapidly removed and fixed for histopathological examination. In all instances, bowel removed immediately after sacrifice was normal whereas after delays as short as 30 minutes it was abnormal (P less than 0.001), becoming markedly so after 60 minutes. The prominent features were detachment and lysis of mucosal epithelial cells. The rate of autolysis was not altered in 14 day old animals or in carcasses held at 20 degrees C or 37 degrees C. Investigators of bowel injury syndromes in young rats should be aware that histopathological studies will be valid only if specimens held at room temperature are fixed within 15 minutes of death.

Animals↗
PubMed1978

Autolysis induction of malignant lymphoblasts.

BALB/C mice were treated with epsilon aminocaproic acid (EACA), 0.1 to 3.2 mg/g body weight, subcutaneously every 24 hours for six days, starting on the second day after intraperitoneal transplantation of L5178Y lymphoma. Complete involution was observed in 20 to 90 per cent of the ascitic tumor and in 50 per cent of the solid tumor 72 hours after EACA was discontinued, tumoral involution and dosage were directly proportional. One hundred per cent of the non treated controls died 10 +/- 0.6 days after intraperitoneal lymphoma transplantation. During tumor involution malignant cells underwent autolysis and were attacked or phagocytized by activated macrophages. Since EACA is a proteolytic enzyme inhibitor, inhibition during treatment and activation of these enzymes after EACA was discontinued could have been the cause of autolysis of the L5178Y lymphoma cells.

Aminocaproates↗
PubMedDate not supplied

[Ribosomal RNA degradation in rat skeletal muscle in the process of autolysis].

Comparative histochemical study of RNA content in normal and autolyzed within 72 hrs muscle tissue showed that the nucleic acid well retained during autolysis but the tissue was simultaneously destructed. Polymerization of rRNA in autolyzed tissue proved to depend on temperature of dead animals storage. An increase of temperature from 0 degrees to 21 degrees did not affect the rRNA yield. But amount of latent breaks, which were found in rRNA by methods of formamide and temperature treatment, was increased depending on increase in temperature and on length of animal storage after death. The latent breaks appear to be accumulated in animal tissues during autolysis.

Animals↗
PubMedDate not supplied

[Catabolic changes in endogenous lipids in rat adrenal glands during autolysis].

Alterations in lipid composition of rat adrenal glands were studied at various periods of autolysis by means of micro-thin layer chromatography. Phospholipids, cholesterol and its esters proved to be the most labile lipid fractions of the tissue. At early period of autolysis (4 hrs) content of total lipids was decreased mainly due to lowering in amount of phospholipids, cholesterol and its esters and only slightly - to lowering in content of free fatty acids. In subsequent necrobiotic degradation of adrenal gland tissue (10 hrs) the increase in content of total lipids was related to the distinct elevation in amount of free fatty acids and glycerides. Mechanisms of the phenomenon observed are discussed.

Adrenal Glands↗