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Query: UMLS:C0424790 (rigors)
 822 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Small length changes were imposed on pairs of sartorius muscles from Rana temporaria and Rana pipiens in rigor and the mechanical and thermal responses studied. Rigor was induced by soaking the muscles overnight at 0 degrees C in a physiological salt solution containing 1.5 mM sodium azide and 0.4 mM sodium iodoacetate. Tension was measured at both the tibial and the pelvic ends of the preparation. Muscles were held at a steady tension of 20 to 76 kN m-2 and stretches or releases of 0.02 to 0.6 mm applied in pairs, with the initial change reversed several hundred milliseconds later. Single stretches resulted in heat absorption and releases in heat production by the preparation. Net heat production resulted from complete cycles of length changes larger than 0.1 mm, whether the initial change was a stretch or a release. The heat produced by the complete cycle was attributed to the movement of the muscles over the thermopile. It was proportional to the difference in tension between the tibial and pelvic ends of the preparation and increased with the size and speed of the length change. Half the heat produced by a complete cycle of length changes was subtracted from the thermal response recorded in the first half-cycle to obtain the reversible component of the response. The reversible component was linearly related to the tension change for all sizes and speeds of length change which were studied, with the heat:tension ratio ranging from -0.0093 to -0.0179 in eleven muscles (mean -0.0128 +/- 0.0009). The constancy of the heat:tension ratio in rigor muscles over a wide range of mechanical conditions indicates that the source of the thermal changes is the normal elasticity of the preparation. Since the size of the ratio is approximately the same as that measured in active muscles, the tension-dependent component of the thermal response to length changes applied to active muscles is probably also of elastic origin.
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PMID:The thermoelastic effect in rigor muscle of the frog. 348 55

The decision of the editors to solicit a review for the Medical Progress series of this journal devoted to current concepts of the renal handling of salt and water is sound in that this important topic in kidney physiology has recently been the object of a number of new, exciting and, in some instances, quite unexpected insights into the mechanisms governing sodium excretion. These developments have come about largely as a consequence of the fact that segments of nephrons previously inaccessible to direct study are now readily accessible. Many of the findings to be discussed argue for extensive revision of a number of our current widely held views concerning the renal handling of sodium chloride and water. In the opinion of the authors, the strength of this argument rests in the fact that many of these new findings were obtained under circumstances that enabled workers to gain more direct access to the nephron than has been possible heretofore. This is not to say that areas of controversy and disagreement no longer exist. Wherever possible, these have been identified. In attempting to provide a comprehensive review of this topic, it has been necessary at times to overgeneralize and to disregard minor deficiencies in some of the studies cited. Finally, we wish to emphasize that a considerable portion of the information contained herein derives from work still under active investigation. Much of this contemporary work will undoubtedly withstand the rigors of future experimental scrutiny. It is inevitable, however, as William James so aptly noted in the quotation cited below, that some of our present ideas will need to be abandoned or revised in favor of newer, more convincing evidence. Seen in this light, the present effort is intended as nothing more than a timely survey of this active and fertile topic in renal physiology.
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PMID:Current concepts of sodium chloride and water transport by the mammalian nephron. 459 Aug 88

The Aeromonas species uncommonly cause disease in humans. We report portal pyaemia secondary to Aeromonas hydrophila bacteraemia occurring in a 71-year-old Chinese man with no history of hepatobiliary disease or malignancy. He presented with fever, rigors and abdominal bloating for four days and was subsequently found to have Aeromonas hydrophila bacteraemia, portal vein thrombosis and a psoas abscess. He was treated with ciprofloxacin and had a good recovery. Aeromonas hydrophila infection is an uncommon cause of intestinal and extraintestinal infection in man, but must be suspected in immunocompromised hosts and in those exposed to brackish or salt water.
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PMID:Aeromonas hydrophila bacteraemia and portal pyaemia. 1841 29

1. X-ray diffraction studies of sartorius muscles of Rana pipiens were made in a new x-ray diffraction camera which permits exposures of 3 to 6 minutes. The object-film distance can be varied from 20 to 80 mm; the muscle inside the camera can be electrically stimulated while contracting isotonically or isometrically, and can be observed by a special device. After exposures up to 30 minutes (approximately 40,830 r) muscles are still alive and responsive. 2. Contrary to the x-ray diffraction pattern of powdered dry muscle, which pattern consists of two rings corresponding to spacings of 4.46 A.u. and 9.66 A.u., both moist and dried whole sartorius muscle show signs of orientation in both rings, consisting of two equatorial streaks (wet) or points (dry) and meridional sickles. The moist muscle shows in addition a diffuse water ring. The spacings corresponding to the orientation points and elliptical structure show only slight differences in moist and dried samples. Through statistical computations based on two different series consisting of thirteen moist and twenty-eight dried samples, and nine muscles before and after drying, it was shown that only the divergence in the smaller spacing has some real significance, which indicates that most water of the moist muscle is bound intermolecularly. Upon resoaking of dried muscle the x-ray diffraction pattern of the moist muscle is restored. 3. Stretching of muscle by weights below the breaking point produces an additional well defined diffraction line, corresponding to a spacing of 4.32 A.u. A similar diffraction line can be produced in frog tendon upon stretching. 4. The influence of heat on the x-ray diffraction pattern of muscle depends upon the maximum temperature and the length of action; 5 minutes at 50 degrees C. markedly reduces the orientation of the sample; 5 minutes' immersion in boiling Ringer's solution destroys the orientation and produces a ring corresponding to a spacing of 5.3 to 5.5 A.u. in the moist and sharpening of the backbone reflection in the dried specimen. 5. Ultraviolet light brings forth changes in the x-ray diffraction pattern varying with the intensity of the irradiation. Ultimately a disappearance of the equatorial points and of the outside sickles is achieved while the elliptical shape of the outside ring and its diffuseness persist. In addition two salt rings characteristic of NaCl indicate that the irradiated muscles have become permeable to the surrounding medium (Ringer's solution). 6. Both faradic and single shock electrical stimulation were tried on muscles. If shortening of the muscle is prevented either by sufficient weight or by tying the muscle in a frame, no changes in the x-ray diffraction pattern occur; if the muscle is allowed to shorten without weights or by using insufficient weights, then the orientation either disappears completely or partially. When the muscle is stretched while contracted by electrical stimulation the orientation of the x-ray diffraction pattern reappears. 7. A number of salts with uni- and bivalent ions in concentrations corresponding osmotically to 0.73 per cent NaCl and 10 per cent NH(4)Cl were studied in their effects upon the x-ray diffraction of muscles. Of the salts with univalent ions in the lower concentration only KCl causes a marked decrease of orientation and an increase in the permeability of the fiber membranes. Similar effects on the orientation seem to be produced by CaCl(2) while MgCl(2) causes rather a more pronounced orientation. At hypertonic salt concentrations the orientation disappears completely and the corresponding salt rings become visible. Besides, NaCNS seems to have a specific effect on the outside ring and LiCl produces a ring at 21.3 A.u. and a splitting of the outside ring. 8. Strong mineral and lactic acids in concentrations up to 0.005 N have little if any influence upon the x-ray diffraction of muscles. A further increase in acidity to 0.01 N and above destroys the orientation completely, causes sharpening of the backbone reflection, and increased membrane permeability. These changes are irreversible upon neutralization. Also the effects of swelling upon the water ring of fresh muscle become manifest. Weak acids at higher concentrations show an effect similar to that of strong acids. 9. Rigor mortis produces a more or less complete loss of orientation. The muscles show signs of increased permeability. 10. Alkalies destroy the orientation of the x-ray diffraction pattern. The effective concentration is higher than the corresponding amount of acid. 11. Formaldehyde produces only minor changes in the x-ray diffraction patterns of muscles. 12. The effects of alcohol depend primarily upon the concentration applied. Low concentrations (5 per cent) seem to have a passing stimulating effect, at concentrations of 15 per cent, the anesthetizing effect becomes manifest in well defined orientation. The diameter of the water ring is reduced. If 95 per cent alcohol is allowed to act upon muscle for more than 12 minutes, then the orientation disappears completely and the backbone spacing becomes as sharp as in boiled muscle. 13. The effects of chloroform depend upon whether the muscle is allowed to contract or not. Only if the muscle is allowed to contract in chloroform-saturated Ringer's solution is the orientation lost and salt rings appear as well as a ring corresponding to a spacing of 22 A.u,, which has been observed in other changes in muscles. 14. In muscles allowed to shorten in a caffeine-Ringer's solution the orientation disappears, salt rings become visible as well as a decrease in size of the water ring; a new arc corresponding to a spacing of 4.18 A.u. was observed in one case.
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PMID:X-RAY DIFFRACTION STUDIES ON FROG MUSCLES. 1987 11