Shock-induced Changes Research Articles

Heat shock-induced changes in the structural stability of proteinaceous karyoskeletal elements in vitro and morphological effects in situ.

Karyoskeletal protein fractions prepared from Drosophila melanogaster embryos contain morphologically identifiable remnants of nuclear pore complexes and peripheral lamina as well as what appears to be an internal nuclear "matrix" (Fisher, P. A., M. Berrios, and G. Blobel, 1982, J. Cell Biol., 92: 674-686). Structural stability of these proteinaceous assemblies is dependent on thermal incubation in vitro (37 degrees C, 15 min) before subfractionation of nuclei. In the absence of such incubation, greater than 90% of the total karyoskeletal protein including major polypeptide components of internal "matrix," pore complexes, and the peripheral lamina, is solubilized by 1 M NaCl. In vivo heat shock induces karyoskeletal stabilization resembling that resulting from thermal incubation in vitro. Immunocytochemical studies have been used to establish the effects of heat shock on the organization and distribution of major karyoskeletal marker proteins in situ. Taken together, these results are consistent with the notion that in vivo, regulation of karyoskeletal plasticity (and perhaps form) may be a functionally significant component of the Drosophila heat shock response. They also have broad practical implications for studies pertaining to the structure and function of karyoskeletal protein (nuclear "matrix") fractions isolated from higher eukaryotic cells.

A mixing rule for the shock parameters during phase transitions at high pressures

A study is made of shock-induced phase changes. The transition zone is considered as a mixture of both the initial and the final phases, at any stage of the transition. It is assumed that the material always responds linearly in U S − U P. Only transitions at U S constant are considered. A mixing rule is introduced by the assumption that the coefficients of the linear relationship during the transition are linear functions of the changing molar fractions of the two phases. This mixing rule is first tested for some mixtures. A few algebraic relations in the P − V and U S − U P representations during the phase transitions are obtained. Some of these relations are used to predict the characteristics of reported transitions.

Involvement of different opioid receptor subtypes in electric shock-induced analgesia and motor suppression in the rat

We have investigated the correlation of electric shock-induced behavioral changes and functional alterations of endogenous opioid receptor subtypes. The degree of electric shock-induced behavioral changes, such as analgesia and motor suppression, was dependent on the duration of and time after electric shock application. The electric shock-induced behavioral changes were completely antagonized by naloxone. The apparent development of tolerance to both behavioral effects as a result of successive daily electric shock was different: Tolerance to electric shock-induced analgesia developed after 2 days' successive electric shock application, while tolerance to motor suppression was not observed even after 7 days' successive electric shock application. There was a decrease of [ 3H][D-Ala 2, Met 5]enkephalinamide ([ 3H]DAMEA, δ agonist) binding and an increase of [ 3H]naloxone (μ antagonist) binding when potent electric shock-induced analgesia developed. On the other hand, the binding of [ 3H]DAMEA and [ 3H]ethylketocyclazocine (κ agonist) was significantly changed when locomotion was suppressed. These results suggest strongly that different opioid systems may participate in electric shock-induced analgesia and motor suppression: electric shock-induced analgesia and motor suppression may be mediated by μ/δ and κ/δ receptors, respectively.

Specific surface area studies of shock-modified inorganic powders

Modification of inorganic powders with high-pressure shock-wave loading is of interest for shock-activated sintering, material synthesis, shock-enhanced catalytic activity, dynamic compaction, and shock-enhanced solid-state reactivity. The specific surface area of shock-modified powders is a direct quantitative measure of powder morphology changes, yet few studies have been carried out on powders subjected to controlled shock-loading conditions. In the present work aluminium oxide, zinc oxide, aluminium nitride, titanium carbide and titanium diboride powder compacts were subjected to controlled shock-loading to peak pressures of from 4 to 27 GPa at various starting densities, and characterized with specific surface area measurements by the BET (gas adsorption) method. Low-temperature cyclical thermal pretreatment and outgassing pretreatment of the shock powders at 250° C were employed; the former improves the reliability of the BET measurements, and makes the surfaces of the shock-modified powders more chemically active than those of the starting powders. Each powder shows a somewhat different response to shock-loading, ranging from a decrease in specific surface by a factor of six for zinc oxide to a 200% increase for titanium diboride. Shock-induced changes in specific surface show four characteristic behaviours as shock pressure is increased. Well-understood and controllable shock-loading conditions are found to be essential to shock-modification studies. An update on earlier measurements on rutile, zirconia and silicon nitride is also reported.

Photoluminescence determination of the pressure and temperature of the shock wave induced by a picosecond laser pulse in the layered semiconductor GaSe.

The pressure and temperature of the shock waves generated by a picosecond laser pulse in the layered semiconductor gallium selenide were determined by shock-induced changes of the photoluminescence spectra. The peak pressure was measured to be about 13 kbar, while the temperature remained the same during the measured time range. Our results are consistent with the pressure measurements made with a piezoelectric transducer.

Changes in chromatin and the phosphorylation of nuclear proteins during heat shock of Achlya ambisexualis.

Heat shock led to marked changes in the apparent levels of phosphorylation of nuclear proteins in the fungus Achlya ambisexualis. We characterized these heat shock-induced changes in nuclear proteins on two types of two-dimensional polyacrylamide gel systems. We report here that one of two Achlya H3 histones (H3.1) and also the oomycete histone alpha appear to be highly phosphorylated with heat shock. Additional changes observed in acid-soluble nuclear proteins included an apparent increase in the 32P labeling of a 43,000-molecular-weight protein and the dephosphorylation of a major group of Achlya phosphoproteins in the 30,000-to-32,000-molecular-weight range. The changes in protein phosphorylation were accompanied by striking changes in the morphology of Achlya nuclei. Nuclei in the heat-shocked cells, but not in control cells, exhibited marked chromatin condensation and contained bundles of filaments which were approximately 4 nm in diameter. Concomitantly, the bulk of chromatin from heat-shocked nuclei showed a decreased sensitivity to digestion with the enzyme DNase I relative to chromatin from control cells.

Changes in chromatin and the phosphorylation of nuclear proteins during heat shock of Achlya ambisexualis.

Heat shock led to marked changes in the apparent levels of phosphorylation of nuclear proteins in the fungus Achlya ambisexualis. We characterized these heat shock-induced changes in nuclear proteins on two types of two-dimensional polyacrylamide gel systems. We report here that one of two Achlya H3 histones (H3.1) and also the oomycete histone alpha appear to be highly phosphorylated with heat shock. Additional changes observed in acid-soluble nuclear proteins included an apparent increase in the 32P labeling of a 43,000-molecular-weight protein and the dephosphorylation of a major group of Achlya phosphoproteins in the 30,000-to-32,000-molecular-weight range. The changes in protein phosphorylation were accompanied by striking changes in the morphology of Achlya nuclei. Nuclei in the heat-shocked cells, but not in control cells, exhibited marked chromatin condensation and contained bundles of filaments which were approximately 4 nm in diameter. Concomitantly, the bulk of chromatin from heat-shocked nuclei showed a decreased sensitivity to digestion with the enzyme DNase I relative to chromatin from control cells.

Microcirculation and hemorrhagic shock

Blood loss is followed by compensatory cardiovascular readjustments that favor the maintenance of blood flow to central vital organs rather than to peripheral tissues. The microcirculatory changes that occur in skeletal muscle in shock states are of major importance, since skeletal muscle is not only the largest cell mass of the body but also one of the major target organs for neurohumorally mediated compensatory vascular readjustments. Intravital microscopic studies show that the microvascular blood flow in skeletal muscle is intermittent in the early posthemorrhagic period. This probably reflects an interplay between α-adrenergic vasoconstrictor and β-adrenergic vasodilator activities, which serves to enhance a compensatory mobilization of interstitial fluid into the vascular compartment. A period of complete microcirculatory arrest is then seen, followed by reperfusion engaging only 30% to 50% of the capillaries that were seen perfused in resting skeletal muscle. The microvascular blood flow in shock is further characterized by a pronounced heterogeneity in distribution. Many capillaries remain constantly unperfused, while in others a slow, intermittent blood flow is seen. Obstruction of many capillaries by white blood cells and their slow passage through other capillaries seem to be the main reasons for the maldistribution of capillary blood flow in shock. Red blood cell aggregates obstructing capillary blood flow are not seen. The heterogeneous tissue perfusion is accompanied by local variations in cellular hypoxic injury, as is evidenced by multifocal measurements of tissue oxygen tension and by cellular transmembrane potential registrations. The blood-tissue exchange of substances is impaired because of the reduction in capillary surface area and changes within the interstitial compartment. Therefore, shock-induced metabolic changes in skeletal muscle remain mainly local and are not at all, or only to a limited extent, reflected in central blood. Following volume treatment the heterogeneity in capillary perfusion persists, since white blood cells often remain trapped in capillaries and obstruct blood flow. Treatment of shock with hypertonic solutions, ATP-MgCl 2, or steroids could be beneficial by enhancing the mobilization of trapped white blood cells. Microcirculatory disturbances and their local metabolic consequences in skeletal muscle of critically ill patients can be monitored in the intensive care unit by the use of microelectrodes for continuous or intermittent measurements of tissue gas tensions (P 0 2 , P CO 2 ), tissue pH, and tissue potassium levels.

Uncontrollable shock proactively increases sensitivity to response-reinforcer independence in rats.

Learned helplessness theory predicts that animals exposed to inescapable shock acquire an expectancy of response-reinforcer independence, which proactively interferes with learning of response-reinforcer dependence. The theory also predicts that this expectancy can increase sensitivity to subsequent instances of response-reinforcer independence. These experiments test the latter prediction in a paradigm that minimizes the confounding effects of shock-induced activity deficits. Rats were trained to respond for food, then given either escapable, inescapable, or no shock. Subsequently, they received two sessions of response-contingent food followed by sessions of noncontingent food deliveries. During this phase, inescapably shocked animals decreased responding faster than did controls. Experiment 2 replicated this finding with a different schedule of food delivery and a procedure that more directly minimized the possibility that the outcome is due to either direct or indirect shock-induced activity changes. These results support the prediction that uncontrollable aversive events can increase an animal's sensitivity to noncontingent response-reinforcer relationships.

ChemInform Abstract: SHOCK‐INDUCED CHANGES IN THE ELECTRONIC SPECTRA OF LIQUID CARBON DISULFIDE

Chemischer InformationsdienstVolume 14, Issue 19 Physical Organic Chemistry ChemInform Abstract: SHOCK-INDUCED CHANGES IN THE ELECTRONIC SPECTRA OF LIQUID CARBON DISULFIDE K. M. OGILVIE, K. M. OGILVIESearch for more papers by this authorG. E. DUVALL, G. E. DUVALLSearch for more papers by this author K. M. OGILVIE, K. M. OGILVIESearch for more papers by this authorG. E. DUVALL, G. E. DUVALLSearch for more papers by this author First published: May 10, 1983 https://doi.org/10.1002/chin.198319049AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume14, Issue19May 10, 1983 RelatedInformation

The role of norepinephrine and acetylcholine in mediating escape deficits produced by inescapable shocks

This study examined the role of neurochemical changes produced by inescapable shock, specifically the depletion of norepinephrine (NE) and enhancement of acetylcholine (ACh), in mediating subsequent inescapable shock-induced deficits in escape acquisition in rats. Enhancement of these neurochemical changes by injections of the NE synthesis inhibitor, FLA-63 (10 mg/kg), or the anticholinesterase, eserine sulphate (3 X 0.5 mg/kg), during the inescapable shock enhanced the subsequent escape deficits observed 3 days later. In contrast, these drugs had no effect on the subsequent escape behavior of rats that were not exposed to inescapable shock. Since these effects could not be attributed to carry-over or state-dependent effects of the drugs, these data suggest that the magnitude of the escape deficit produced by prior inescapable shock is dependent on the magnitude of the initial inescapable shock-induced changes in NE and ACh.

Shock-induced changes in the electronic spectra of liquid CS2

Experimental techniques are described for electronic time-resolved reflection and transmission spectroscopy in a thin liquid CS2 sample undergoing successive shocks by reverberation. Transmission spectra in the near UV and visible show progressive shifting of the red edges of absorption bands with shock pressure. At 55 kbar, extinction of the transmitted signal is complete for wavelengths between 2500 and 4100 Å, but absent at longer wavelengths. At 120 kbar extinction extends through the visible as well. Reflection experiments suggest that extinction is due to coherent scattering. Relaxation in both reflected and transmitted light at 120 kbar is in accord with other observations relating to shock-induced decomposition.

Shock-induced changes in the sodiumpotassium adenosine triphosphatase enzyme system in dog hearts

The effects of endotoxic shock on the partial reaction of the (Na + + K +)-ATPase enzyme system, K +-activated para-nitrophenylphosphatase (K +-PNPPase), and on ouabain binding were studied in isolated adult dog heart myocytes. Results obtained 4 hr after endotoxin administration showed that the kinetic parameters of K +-PNPPase such as V max and K m for K + activation, and V max, S 0.5, and the Hill coefficient for Mg 2+ and para-nitrophenylphosphate saturation were not altered. However, the sensitivity of K +-PNPPase to ouabain inhibition was decreased markedly; the I 50 value for ouabain inhibition was increased from the control value of 0.39 μ M to 2.2 μ M in endotoxic shock. Results obtained from ouabain binding studies indicated that the K d for high-affinity binding was increased by 36% with no change in the K d for low-affinity binding and no change in the total number of binding sites. The average affinity for ouabain binding at low fractional occupancy of receptor sites was markedly decreased. The effect of ouabain on K +-PNPPase activity was changed from inhibition to activation when less than 32% of the receptor sites were occupied. These data indicate that 4 hr after endotoxin administration, the total number of ouabain receptor sites and the dephosphorylation process of the enzyme cycle were not altered, but the coordination of the ouabain receptor subunit and the catalytic subunit of the enzyme system was impaired. Based on these results, it is concluded that the therapeutic value of cardiac glycosides as a means of improving myocardial contractility during endotoxic shock should be reevaluated.

Effect of direct-current countershocks on regional myocardial contractility and perfusion. Experimental studies.

Very high energy electrical countershocks can cause morphologic damage to the myocardium. In this study we searched for functional correlates of these shock-induced morphologic changes. We used ultrasonic sonomicrometers to measure myocardial contractility and radiolabeled microspheres to assess perfusion. Acute and chronic experiments were conducted in 45 dogs, assessing the effect of both direct (epicardial) and transthoracic shocks on beating and fibrillating hearts. High-energy or rapidly repeated epicardial shocks caused subepicardial contraction abnormalities. This indicates that electrical current delivered to the myocardium in sufficiently high amounts and concentration can cause functional damage. Thus, in open-chest defibrillation during cardiac surgery, low energies (10-20 J) should be used initially and higher energies resorted to only if lower-energy shocks fail. However, single and multiple transthoracic shocks up to 460 J delivered energy caused no detectable contraction abnormalities. Myocardial perfusion did not fall after shocks. Thus, high-energy transthoracic shocks may have no deleterious effects on the contraction and perfusion of normal myocardium.

Dynamic Compression of Earth Materials

Shock wave techniques have been used to investigate the pressuredensity relations of metals, silicates, and oxides over the entire range of pressures present in the earth (3.7 x 10(6) bars at the center). In many materials of geophysical interest, such as iron, wüstite, calcium oxide, and forsterite, major shock-induced phase changes dominate the compression behavior below pressures of 10(6) bars. The shock wave data for the high-pressure phases of these minerals lead to important inferences about the composition of the lower mantle and outer, liquid core of the earth. The lower mantle of the earth appears to have a slightly higher density than is inferred to correspond to the behavior of an olivine-rich assembiage of the same composition as the upper mantle. The core has a density some 10 percent less than that of pure iron and may have 9 to 12 percent sulfur or about 8 percent oxygen by weight.

Dielectric properties of shock-wave-compressed PMMA and an alumina-loaded epoxy

One-dimensional shock-compression experiments were performed on specimens of polymethyl methacrylate (PMMA) and an alumina-loaded epoxy. The specimens were placed in an electric field before the introduction of the shock, and displacement currents resulting from shock-induced changes in the size and dielectric properties of the specimen were measured. The observed current histories are in good accord with a model based on a stress-dependent dielectric relaxation function. The relaxation effects in the alumina epoxy are much larger than those in the polymethyl methacrylate.

Shock-induced activity changes, adrenal lipid depletion and brain weight in mice: A genetic study

Motor activity was evaluated before and after a brief electric shock. Whereas small genetic differences in activity were apparent prior to shock, large group differences occurred following shock. C57 mice did not freeze following a shock; DBA mice showed prolonged freezing; and the F 1 hybrids froze only briefly. Backcross groups revealed segregation for postshock activity. Adrenal lipid depletion, as revealed by the absence of Sudan staining in the adrenal cortex, was detected in many male mice, but no correlation with either pre- or postshock activity was detected. Inheritance of adrenal lipid depletion clearly was not monogenetic.

Morbid-anatomical findings in human bone marrow in shock (author's transl)

In a post mortem study of shock-induced changes in the bone marrow, marrow from six different parts of the skeletal system was examined in a total of 109 patients. The comparison of a group of 64 subjects deceased in shock conditions with a control group of 25 deceased without shock showed: In 76,6% of all patients with shock, fibrin networks were found in the sinus and perisinoidal interstice of bone marrow. This can be demonstrated abundantly in every fourth patient with shock. Microthrombi and emboli occluding vessels in the marrow were seen in only 6.3% of the shock cases (controls 0%). The different forms of fibrin precipitates appear most commonly after shock caused by infection. Platelet aggregates in the vessels are seen in 28.2% of all cases with shock (controls 8%). 5% of the cases with shock showed infarction-like necroses of the bone marrow and a further 23% necroses of small cell groups. In every fifth patient with shock, a great number of nucleated blood cells and their precursors were found in the marrow sinus (controls 8%). In a third group of 20 patients with serious illness alledgedly without shock, 45 per cent had a fibrin network when compared with the control group. When several of these findings are present simultaneously, one can apply the term "shock marrow".

Histochemical changes in gastric mucosubstances in patients with acute and chronic ulcer disease.

The several types of epithelial cells in human gastric mucosa produce different mucosubstances. The surface epithelium largely forms a neutral mucosubstance except that in about two-thirds of the specimens the deep foveolar cells produce a slight to moderate amount of a mucosubstance apparently containing sulfate esters and carboxyl groups. Mucous neck cells often exhibit a neutral mucosubstance but in about onehalf of the stomachs reveal a slight to moderate reactivity indicative of sulfated mucosubstance. Chief cells contain a sulfated mucosubstance with unique histochemical properties. Mast cells vary widely in prevalence but those in the gastric mucosa appear depleted of stored mucosubstances when compared with those in the gastric submucosa or the esophagus. The sulfated mucosubstance normally abundant in human as in canine chief cells appears consistently depleted in patients with stress ulcer or hemorrhagic gastritis. In addition, mucus often appears depleted in the surface epithelium and interstitial edema is present in the superficial mucosa of these patients. These findings appear consistent with the view that biosynthetic activity in chief cells and surface epithelial cells is impaired perhaps secondary to shock-induced circulatory changes in gastric mucosa of patients with stress ulcer or hemorrhagic gastritis.

Hugoniot and release-adiabat measurements for selected geologic materials

Release-adiabat curves have been determined for playa alluvium, tonalite, and novaculite shocked to stresses between 1 and 50 kb by plane impact from a light-gas gun. Particle-velocity/time profiles through the shock compression and the following release were measured at interfaces within the rock target and at the free surface using the principle of a moving conductor in a magnetic field. Steep release-adiabat curves in the stress-volume plane and high rarefaction velocities have been determined for alluvium and tonalite, indicating irreversible compaction. For alluvium, the initial rarefaction velocities are twice the shock velocities, which would cause rapid attenuation of the shock wave propagated in a field experiment. For novaculite, shocked below the Hugoniot elastic limit, the release-adiabat curve lies very close to the Hugoniot. The techniques should be applicable at higher stresses to study such problems as the kinetics of shock-induced phase changes.