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Abstract
One of the most important stages of pregnancy is the activation of uterine contractions that result in the expulsion of the fetus. The timely onset of labour is clearly important for a healthy start to life but incomplete understanding of the precise mechanisms regulating labour onset have prohibited the development of effective and safe treatments for preterm labour. This review explores the activation of the myometrium at labour onset, focussing on mechanisms of uterine contractility, including those proteins that play an important role in smooth muscle contractility. The review primarily focuses on human work but in the absence of human data describes animal studies. A broad overview of myometrial contraction mechanisms is provided before discussing more detailed aspects and identifying areas where uncertainty remains. Also discussed is the recent application of ‘omics’ based approaches to parturition research, which has facilitated an increase in the understanding of myometrial activation.
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Seow CY, Paré PD. Ultrastructural basis of airway smooth muscle contractionThis article is one of a selection of papers published in the Special Issue on Recent Advances in Asthma Research. Can J Physiol Pharmacol 2007; 85:659-65. [PMID: 17823629 DOI: 10.1139/y07-052] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The sliding filament theory of contraction that was developed for striated muscle is generally believed to be also applicable to smooth muscle. However, the well-organized myofilament lattice (i.e., the sarcomeric structure) found in striated muscle has never been clearly delineated in smooth muscle. There is evidence that the myofilament lattice in some smooth muscles, such as airway smooth muscle, is malleable; it can be reshaped to fit a large range of cell dimensions while the maximal overlap between the contractile filaments is maintained. In this review, some early models of the structurally static contractile apparatus of smooth muscle are described. The focus of the review, however, is on the recent findings supporting a model of structurally dynamic contractile apparatus and cytoskeleton for airway smooth muscle. A list of unanswered questions regarding smooth muscle ultrastructure is also proposed in this review, in the hope that it will provide some guidance for future research.
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Affiliation(s)
- Chun Y Seow
- Department of Pathology and Laboratory Medicine and the James Hogg iCAPTURE Centre, St Paul's Hospital, University of British Columbia, Vancouver, BC, Canada.
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Tetaert D, Moreau O, Han KK, Hildebrand HF, Biserte G. SIsolation and characterization of "L17" light chain of myosin from bovine uterine smooth muscle. Biochimie 1977; 59:337-9. [PMID: 142522 DOI: 10.1016/s0300-9084(77)80151-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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6
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Urea-disc-electrophoresis of actin, tropomyosin, troponin, α-actinin, β-actinin and the extra protein fraction from striated muscle. Food Chem 1977. [DOI: 10.1016/0308-8146(77)90003-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Abstract
A myosin-like protein was identified in isolated rabbit liver cells. It was extracted with high-ionic-strength buffer containing ATP, and purified by gel filtration in the presence of iodide. The myosin polypeptide was indistinguishable in size from the heavy chain of muscle myosin as determined by electrophoresis on polyacrylamide gels and gel filtration in the presence of sodium dodecyl sulfate. The hepatic myosin had an amino acid composition similar to that of muscle myosin, but lacked 3-methylhistidine. The Mg2+ -ATPase of the myosin was not activated by muscle actin. At low ionic strength, in the presence of Mg2+, the protein aggregated to form bipolar filaments 0.3 mum in length. A protein which resembled muscle actin in size and amino acid composition was extracted along with the myosin. Based on scans of stained sodium dodecyl sulfate polyacrylamide gels, the myosin content was estimated as 0.3% to 0.4% of the cell protein. The actin-like component was present in approximately ten-fold excess by weight. This ratio suggests that the organization and function of myosin in the hepatocyte is very different from that in the muscle cell.
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Maillot KV, Zimmermann BK. The solubility of collagen of the uterine cervix during pregnancy and labour. ARCHIV FUR GYNAKOLOGIE 1976; 220:275-80. [PMID: 946942 DOI: 10.1007/bf00673411] [Citation(s) in RCA: 39] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The solubility of collagen during pregnancy and labour was studied in tissue specimens of the uterine cervix of 48 women in childbearing age. In the course of pregnancy the fractions of collagen which are soluble in 0.175 M acetic acid at +5 degrees C and in 8 M urea at +40 degrees C increased continuously in relation to the total collagen content and dry weight. The highest values were found during labour at full cervical dilatation and also immediately post partum. The results show that for the dilatation of the cervical canal during labour biochemical changes must take place not only in the ground substance, but also in the collagenfibres.
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Megerman J, Murphy RA. Myosin from arterial smooth muscle: isolation following actin depolymerization. BIOCHIMICA ET BIOPHYSICA ACTA 1975; 412:241-55. [PMID: 85 DOI: 10.1016/0005-2795(75)90038-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The contractile proteins from arterial smooth muscle are highly soluble, and can be extracted at I = 0.05. However, they can be precipitated by a prolonged dialysis at pH 6 to give an actomyosin with a high, although variable, actin:myosin ratio. The sedimentation behavior of this actomyosin at high ionic strength was examined as a function of pH, protein concentration and composition by preparative ultracentrifugation. Comparisons with synthetic skeletal muscle actomyosins of similar composition demonstrated significant differences in the behaviors of these two systems. It was found that much smooth muscle actomyosin is not dissociated by normally relaxing conditions, and that it sediments at a slower rate than F-actin. The solubility of the supernatant protein (a myosin-enriched actomyosin) in 0.2 M K Cl (pH 7) depended on the pH during centrifugation. A lower solubility was associated only with a higher actin concentration in the supernatant, suggesting a dependence on actin repolymerization. Pure myosin was selectively precipitated from the supernatant by polyethylene glycol-6000, but only when the protein was soluble at low ionic strength. The solubility of purified myosin was similar to that of myosin from striated muscles. A relationship between the presence of depolymerized actin and the high solubility of smooth muscle contractile proteins is suggested.
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Sobieszek A, Bremel RD. Preparation and properties of vertebrate smooth-muscle myofibrils and actomyosin. EUROPEAN JOURNAL OF BIOCHEMISTRY 1975; 55:49-60. [PMID: 126155 DOI: 10.1111/j.1432-1033.1975.tb02137.x] [Citation(s) in RCA: 191] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
A new technique for obtaining a myofibril-like preparation from vertebrate smooth muscle has been developed. An actomyosin can be readily extracted from these myofibrils at low ionic strength and in yields 20 times as high as previously reported. The protein composition of all preparations has been monitored using dodecylsulfate-gel electrophoresis. By this method smooth muscle actomyosin showed primarily only the major proteins, myosin, actin and tropomyosin, while the myofibrils contained, additionally, three new proteins not previously described with polypeptide chain weights of 60000, 110000 and 130000. The ATPase activities of both the myofibrils and actomyosin preparations are considerably higher than previously described for vertebrate smooth muscle. They are sensitive to micromolar Ca2+ ion concentrations to the same degree as comparable skeletal and cardiac muscle preparations, even though troponin-like proteins could not be identified in these smooth muscle preparations. From the latter observation and the presence of Ca2+-sensitivity in tropomyosin-free actomyosin it is suggested that this calcium sensitivity is, as in some invertebrate muscles, a property of the myosin molecule.
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11
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Abstract
Smooth muscle cells of the mouse vas deferens fixed with 5% glutaraldehyde contained three types of filaments, namely, thin (50-80) A) filaments, intermediate (100 A) filaments and thick (120-180 A) filments. However, in 2 out of 16 experiments, under identical conditions, the cells did not contain thick filaments. With OSO4 fixation, thin filaments were not prominent, the most obvious being thick (120-250 A) and intermediate (100 A) filaments. After soaking in a modified Ringer solution under no applied tension for one hour, thick filaments (120-180 A) appeared prominently in smooth muscle cells of the mouse vas deferens and thin filaments were in ordered bundles. By 4 hours, thick filaments had increased in size and density, with thin filaments distributed randomly around them. After 8 hours in Ringer, thin filaments were diffuse and difficult to discern, while thick filaments were large (up to 300 A) and electron-dense. Intermediate (100 A) filaments were present in association with dark bodies. Physiological experiments indicated that the intracellular components responsible for the development of a mechanical response were still functional at this time. The presence of "thick filaments" is also reported in degenerating smooth muscle cells of the guinea-pig vas deferens in tissue culture.
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Young LG, Smithwick EB. Extraction of ATP-phosphohydrolase activity from epididymal bull sperm and ultrastructure of flagellar degradation. Exp Cell Res 1975; 90:223-36. [PMID: 122933 DOI: 10.1016/0014-4827(75)90311-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Hofmann W, Goger D. Report on the differentiation of vascular wall smooth muscle cells with the aid of immunofluorescence. VIRCHOWS ARCHIV. A, PATHOLOGICAL ANATOMY AND HISTOLOGY 1974; 363:225-31. [PMID: 4214346 DOI: 10.1007/bf00432803] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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15
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Russell WE. Insolubilization and activation of arterial actomyosin by bivalent cations. EUROPEAN JOURNAL OF BIOCHEMISTRY 1973; 33:459-66. [PMID: 4120978 DOI: 10.1111/j.1432-1033.1973.tb02703.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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Archer FL, Beck JS, Melvin JM. Localization of smooth muscle protein in myoepithelium by immunofluorescence. THE AMERICAN JOURNAL OF PATHOLOGY 1971; 63:109-18. [PMID: 4101056 PMCID: PMC2047465] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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Gröschel-Stewart U. Comparative studies of human smooth and striated muscle myosins. BIOCHIMICA ET BIOPHYSICA ACTA 1971; 229:322-34. [PMID: 4101790 DOI: 10.1016/0005-2795(71)90191-7] [Citation(s) in RCA: 49] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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Yamaguchi M, Miyazawa Y, Sekine T. Preparation and properties of smooth muscle myosin from horse esophagus. BIOCHIMICA ET BIOPHYSICA ACTA 1970; 216:411-21. [PMID: 4251352 DOI: 10.1016/0005-2728(70)90233-1] [Citation(s) in RCA: 35] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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Johnson P, Perry SV. Biological activity and the 3-methylhistidine content of actin and myosin. Biochem J 1970; 119:293-8. [PMID: 4249861 PMCID: PMC1179351 DOI: 10.1042/bj1190293] [Citation(s) in RCA: 63] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
1. The 3-methylhistidine content of myosin varies according to muscle type. It is highest in myosin from white skeletal muscle and lower values are obtained from myosin of red skeletal and smooth muscle. 2. The 3-methylhistidine content of actin was similar in all of the types of muscle from which it was isolated. 3. The 3-methylhistidine of rabbit actin is localized in a single tryptic peptide that was readily modified during fractionation procedures. 4. Photo-oxidation studies indicated that the 3-methylhistidine residues are not essential for adeonsine triphosphatase and actin-combining activities of myosin. 5. During photooxidation G-actin lost completely the ability to polymerize to the F form before all the 3-methylhistidine was destroyed.
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Berl S, Puszkin S. Mg2+ -Ca2+ -activated adenosine triphosphatase system isolated from mammalian brain. Biochemistry 1970; 9:2058-67. [PMID: 4245870 DOI: 10.1021/bi00812a005] [Citation(s) in RCA: 79] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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Panner BJ, Honig CR. Locus and state of aggregation of myosin in tissue sections of vertebrate smooth muscle. J Biophys Biochem Cytol 1970; 44:52-61. [PMID: 4901376 PMCID: PMC2107786 DOI: 10.1083/jcb.44.1.52] [Citation(s) in RCA: 32] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Structures with the characteristics of molecular myosin were identified by electron microscopy in tissue sections of vertebrate smooth muscle. No thick filaments of myosin were found regardless of preparative procedures, which included fixation at rest and in contraction, glycerine extraction, and storage at low pH prior to fixation. Absence of thick myosin filaments and presence of what appear to be myosin molecules is in accord with conclusions based on X-ray diffraction (3, 12) and birefringence data (4) from living smooth muscles at rest and in contraction. Explanations are provided for appearances thought by others (6, 20, 21) to represent thick myosin filaments. Our present observations are in accord with the model for smooth muscle contraction which we have previously proposed (1).
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Ultrastruktur glycerinextrahierter D�nndarmmuskelzellen der Ratte vor und nach Kontraktion. Cell Tissue Res 1970. [DOI: 10.1007/bf00330932] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Adelman MR, Taylor EW. Isolation of an actomyosin-like protein complex from slime mold plasmodium and the separation of the complex into actin- and myosin-like fractions. Biochemistry 1969; 8:4964-75. [PMID: 4243803 DOI: 10.1021/bi00840a046] [Citation(s) in RCA: 62] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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Michael CA. The biochemistry of uterine action. Aust N Z J Obstet Gynaecol 1969; 9:253-7. [PMID: 5264839 DOI: 10.1111/j.1479-828x.1969.tb02568.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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Adenosine Triphosphate-dependent Reaction of 1-Fluoro-2,4-dinitrobenzene with Various Myosins. J Biol Chem 1969. [DOI: 10.1016/s0021-9258(18)63647-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Carsten ME. Role of calcium binding by sarcoplasmic reticulum in the contraction and relaxation of uterine smooth muscle. J Gen Physiol 1969; 53:414-26. [PMID: 4238459 PMCID: PMC2202867 DOI: 10.1085/jgp.53.4.414] [Citation(s) in RCA: 112] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
The binding of calcium by isolated sarcoplasmic reticulum from cow uterus was studied. Sarcoplasmic reticulum was prepared by differential centrifugation. Three fractions were obtained: I, sedimented between 2,500-15,000 x g; II at 40,000 x g; and III, at 150,000 x g. Fraction II was further purified on a sucrose density gradient. All three fractions contained considerable amounts of intrinsic calcium, mostly in fraction I. Calcium binding in the presence of ATP(1) and Mg also was greatest in fraction I, followed by fraction II, with less in fraction III. Without ATP no calcium was taken up. 5 and 10 mM sodium azide partially inhibited calcium binding in fraction I, but not in fraction II, suggesting the presence of some mitochondria or mitochondrial fragments in fraction I. Calcium binding in fraction II was completely inhibited by 3 mM salyrgan; this fraction thus appears to be sarcoplasmic reticulum. ATPase activity was found in all three fractions, highest in fraction II. It is computed that calcium binding in fractions I and II, on the basis of a 50% yield of protein, is sufficient to elicit contraction by supplying calcium to the contractile proteins of the smooth muscle cell and to regulate relaxation and contraction.
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Kotera A, Yokoyama M, Yamaguchi M, Miyazawa Y. Studies on the myosin molecule from smooth muscle. Biopolymers 1969; 7:99-106. [PMID: 5772422 DOI: 10.1002/bip.1969.360070110] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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31
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An electron microscope study of the influence of divalent ions on myosin filament formation in chicken gizzard extracts and homogenates. Tissue Cell 1969; 1:83-96. [PMID: 18631460 DOI: 10.1016/s0040-8166(69)80007-8] [Citation(s) in RCA: 63] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Myosin as well as actin filaments could be seen in negatively stained preparations of fresh chicken gizzard homogenized in buffered KCI (I=0.12, pH 6.85), in a 1 : 1 ratio. Myosin filaments were also present when homogenates were diluted (1 : 9) with solutions containing additional Mg(++) and ATP provided naturally occurring traces of Ca(++) had not been chelated with EGTA. There were no myosin filaments when Mg(++), ATP, Ca(++) or Ca(++) +ATP were added respectively to the diluent. It is suggested that in vivo in relaxed muscles myosin is present in dimers, and only aggregates into filaments at the onset of contraction when Ca(++) are released.
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32
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Gaspar-Godfroid A. [The influence of beta mercaptoethanol on the state of aggregation and ATPase activity of H-meromyosin of bovine carotid]. BIOCHIMICA ET BIOPHYSICA ACTA 1968; 167:622-5. [PMID: 4235425 DOI: 10.1016/0005-2744(68)90057-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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33
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34
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Groschel-Stewart U, Gigli I. A study on the immunologial properties of human uterine and placental contractile protein by immuneadherence. EXPERIENTIA 1968; 24:65-6. [PMID: 4966111 DOI: 10.1007/bf02136798] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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35
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Cretius K, Hannig K, Beier G. [Studies of the solubility and the behavior of collagen in the nonpregnant and pregnant human uterus]. ARCHIV FUR GYNAKOLOGIE 1966; 203:329-53. [PMID: 4862046 DOI: 10.1007/bf00673134] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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36
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37
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Goodall FR. Degradative enzymes in the uterine myometrium of rabbits under different hormonal conditions. Arch Biochem Biophys 1965; 112:403-10. [PMID: 5893905 DOI: 10.1016/0003-9861(65)90072-x] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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38
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39
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Jaisle F. [Isolation of contractile and structural proteins from the human myometrium]. ARCHIV FUR GYNAKOLOGIE 1965; 200:421-7. [PMID: 5897170 DOI: 10.1007/bf00668806] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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