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Forbes MS, Sperelakis N. Membrane systems in skeletal muscle of the lizard Anolis carolinensis. JOURNAL OF ULTRASTRUCTURE RESEARCH 1980; 73:245-61. [PMID: 7218420 DOI: 10.1016/s0022-5320(80)90127-6] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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27
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Forbes MS, Plantholt BA. "Tricks of the trade:" techniques and equipment modification applicable to the preparation of plates of photographs. JOURNAL OF BIOLOGICAL PHOTOGRAPHY 1980; 48:179-81. [PMID: 7216948] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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Forbes MS, Sperelakis N. Structures located at the levels of the Z bands in mouse ventricular myocardial cells. Tissue Cell 1980; 12:467-89. [PMID: 7192018 DOI: 10.1016/0040-8166(80)90037-3] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Within ventricular myocardial cells of the mouse, the myoplasmic regions located immediately adjacent to the Z lines of the sarcomeres contain a variety of structures. These include: (1) transversely oriented 10 nm ('intermediate') filaments that apparently contribute to the cytoskeleton of the myocardial cell; (2) the majority of the transverse elements of the T-axial tubular system; (3) specialized segments of the sarcoplasmic reticulum (SR) that are closely apposed to the sarcolemma or T-axial tubules (junctional SR); (4) 'extended junctional SR' ('corbular SR') that exists free of association with the cell membrane; (5) 'Z tubules' of SR that are intimately apposed to the Z line substance; and (6) leptofibrils. In addition, fasciae adherentes supplant Z lines where myofibrils insert into the transverse borders (intercalated discs) of the cells. The concentration of these myocardial components at the level of the Z lines suggests that a particular specialization of structural and physiological activities exists in the Z-level regions of the myoplasm. In particular, it appears that the combination of intermediate filaments, T tubules, and Z-level SR elements forms a series of parallel planar bodies that extend across each myocardial cell to impart transverse rigidity. The movement and compartmentation of calcium ion (Ca2+) would seem especially active near the Z lines of the myofibrils, in view of the preferential location there of Ca2+-sequestering myocardial structures such as T tubules, junctional SR, extended junctional SR and Z tubules.
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Forbes MS, Sperelakis N. Focal laminate segments in cytoplasmic processes of mouse myocardial fibroblasts. Anat Rec (Hoboken) 1979; 195:575-85. [PMID: 525828 DOI: 10.1002/ar.1091950402] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
In mouse ventricular myocardium, we have found unusual fibroblasts whose cellular processes in some regions are particularly flattened and which contain linearly-arranged, electron-opaque structures ('central laminae"). The morphology of these focal laminate segments of fibroblast processes suggests that the intracellular laminae are adhesive entities which hold the plasmalemmata above and below them in close parallel apposition for short distances.
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Abstract
The effects of ruthenium red (RR) on amphibian and mammalian skeletal muscles and mammalian myocardium were examined. In skeletal muscle cells, a discrete pattern of staining can be brought about within the lumina of the terminal cisternae (junctional sarcoplasmic reticulum [SR]) by sequential exposure to RR and OSO4. After prolonged immersion in RR solution, formation of pentalaminar segments ("zippering") occurs at various points along the longitudinal ("network") SR tubules. Zippering can be elicited in skeletal SR at any stage of preparation prior to postfixation with OSO4. By means of dispersive X-ray analysis, both ruthenium and osmium were seen to be deposited in skeletal muscle junctional SR, and ruthenium was detected in the myoplasm as well. In skeletal muscles whose T tubules were ruptured by exposure to glycerol, the pattern of SR staining and zippering resulting from ruthenium-osmium treatment was not affected. These findings indicate that RR is capable of passage across the sarcolemma of skeletal muscle and that this passage does not occur solely under conditions in which the plasma membrane is damaged. In contrast, RR does not opacify or modify any region of the SR of cardiac muscle. However, after this treatment, randomly distributed opaque bodies, composed of parallel lamellar structures, appear throughout the myocardial cells. A few of these bodies are associated with lipid droplets, but the rest are of unknown origin. The failure of the SR of cardiac muscle to stain after exposure to ruthenium dye (even though this material enters these cells) suggests that the chemical composition of cardiac SR is significantly different from that of skeletal muscle SR.
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Forbes MS, Rennels ML, Nelson E. Caveolar systems and sarcoplasmic reticulum in coronary smooth muscle cells of the mouse. JOURNAL OF ULTRASTRUCTURE RESEARCH 1979; 67:325-39. [PMID: 458928 DOI: 10.1016/s0022-5320(79)80032-5] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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32
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Forbes MS, Plantholt BA, Sperelakis N. Cytochemical staining procedures selective for sarcotubular systems of muscle: modifications and applications. JOURNAL OF ULTRASTRUCTURE RESEARCH 1977; 60:306-27. [PMID: 70538 DOI: 10.1016/s0022-5320(77)80016-6] [Citation(s) in RCA: 108] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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33
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Forbes MS, Rennels ML, Nelson E. Ultrastructure of pericytes in mouse heart. THE AMERICAN JOURNAL OF ANATOMY 1977; 149:47-70. [PMID: 558725 DOI: 10.1002/aja.1001490105] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The pericytes of mouse myocardium are extensively branched cells that form an incomplete layer around the endothelium of capillaries and postcapillary venules. The membranes of pericytes and endothelial cells are connected by specialized junctions. Microtubules, intermediate (10-nm) filaments and microfilaments are oriented within circumferentially-arranged cytoplasmic processes of pericytes so as partially to encircle the endothelial cylinder. The intracellular organization of these myocardial pericytes suggests that they are smooth muscle-like cells which may be capable of influencing microvascular dynamics in the heart.
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Forbes MS, Rennels ML, Nelson E. Innervation of myocardial microcirculation; terminal autonomic axons associated with capillaries and postcapillary venules in mouse heart. THE AMERICAN JOURNAL OF ANATOMY 1977; 149:71-92. [PMID: 855804 DOI: 10.1002/aja.1001490106] [Citation(s) in RCA: 34] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Efferent terminal axons are associated with numerous capillaries and postcapillary venules in both the atria and ventricles of mouse heart. These axons possess ultrastructural characteristics which are typical of peripheral autonomic fibers in other tissues. Many are found near pericytes, in a relationship closely resembling that between terminal axons and smooth muscle cells of larger vessels. To demonstrate adrenergic terminals, mice were pretreated with 5- or 6-hydroxydopamine; examination of these animals' hearts revealed that both adrenergic and cholinergic axons terminate near pericytes and endothelial cells. The results of this study are consistent with the view that there may be a functional innervation of capillaries and postcapillary venules of the mouse heart.
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Khan MA, Earl FL, Farber TM, Miller E, Husain MM, Nelson E, Gertz SD, Forbes MS, Rennels ML, Heald FP. Elevation of serum cholesterol and increased fatty streaking in egg yolk:lard fed castrated miniature pigs. Exp Mol Pathol 1977; 26:63-74. [PMID: 556701 DOI: 10.1016/0014-4800(77)90066-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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36
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Forbes MS, Sperelakis N. Myocardial couplings: their structural variations in the mouse. JOURNAL OF ULTRASTRUCTURE RESEARCH 1977; 58:50-65. [PMID: 833918 DOI: 10.1016/s0022-5320(77)80007-5] [Citation(s) in RCA: 38] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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37
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Gertz SD, Rennels ML, Forbes MS, Kawamura J, Sunaga T, Nelson E. Endothelial cell damage by temporary arterial occlusion with surgical clips. Study of the clip site by scanning and transmission electron microscopy. J Neurosurg 1976; 45:514-9. [PMID: 972335 DOI: 10.3171/jns.1976.45.5.0514] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The effects of temporary vascular occlusion with surgical clips on the underlying endothelial lining were studied with scanning (SEM) and transmission (TEM) electron microscopy. Twenty-five rabbits were anesthetized and both common carotid arteries exposed. A Heifetz clip was used to occlude the right carotid artery for 5, 15, and 30 minutes, and 2 hours in five animals each. The clips were removed and the vessels immediately perfused with glutaraldehyde. In five remaining animals, the right carotid arteries were occluded for 30 minutes followed by removal of the clip and resumption of blood flow for 30 minutes prior to fixation. Combined SEM and TEM examination of the endothelium of compressed segments revealed "craters" and "balloons", blebs and vacuoles, swollen mitochondria, dilated granular endoplasmic reticulum, and subendothelial edema. There were also areas of endothelial cell flattening, discontinuity, and desquamation exposing the subendothelial tissues. Following restoration of flow, platelets and fibrin were found adherent to altered endothelial cells and to exposed subendothelial tissues. Endothelial craters and balloons were also found distal and, significantly less frequently, proximal to the site of occlusion. It is suggested that antiplatelet aggregating agents may prove beneficial for the prevention of thrombus formation at the site of the clip as well as craters and balloons distal to the clip following procedures requiring temporary vascular occlusion.
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38
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Nelson E, Gertz SD, Forbes MS, Rennels MI, Heald FP, Kahn MA, Farber TM, Miller E, Husain MM, Earl FL. Endothelial lesions in the aorta of egg yolk-fed miniature swine: a study of scanning and transmission electron microscopy. Exp Mol Pathol 1976; 25:208-20. [PMID: 1033082 DOI: 10.1016/0014-4800(76)90031-9] [Citation(s) in RCA: 38] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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39
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Gertz SD, Forbes MS, Sunaga T, Kawamura J, Rennels ML, Shimamoto T, Nelson E. Ischemic carotid endothelium. Transmission electron microscopic studies. Arch Pathol Lab Med 1976; 100:522-6. [PMID: 822801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The endothelium of monkey and rabbit common carotid arteries subjected to ischemia was examined by transmission electron microscopy (TEM). The right carotid artery of 24 rhesus monkeys was occluded by proximal and distal placement of removable surgical clips for periods ranging from five minutes to four hours. A single clip was used to occlude the right carotid artery of 15 rabbits for periods ranging from 5 to 30 minutes. With TEM, numerous blebs, intracytoplasmic vacuoles, membranous whorls, and pseudopodia were found in the endothelium of arterial segments subjected to ischemia by double or single clipping for as little as five minutes. Following occlusion of one hour or longer, disruption of interendothelial junctions was also noted. These TEM findings were compared with earlier TEM studies of the response of endothelium to other injurious stimuli and with previous scanning electron microscopic studies in which the same ischemic models were utilized.
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Forbes MS, Sperelakis N. The presence of transverse and axial tubules in the ventricular myocardium of embryonic and neonatal guinea pigs. Cell Tissue Res 1976; 166:83-90. [PMID: 942885 DOI: 10.1007/bf00215127] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Developing transverse (T) tubules are found in embryonic guinea pig ventricular myocardium after approximately eight weeks of gestation. By the time of birth (nine weeks total gestation); longitudinally-oriented axial tubules connected to the T tubules also have formed, and the majority of cells closely resemble those of the adult. The form taken by the developing T and axial tubules suggests that they are generated in a manner similar to that for T tubules in chick and rat skeletal muscle, namely by repeated formation of caveolae.
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Ward MD, Forbes MS, Johns TR. Neostigmine methylsulfate. Does it have a chronic effect as well as a transient one? ARCHIVES OF NEUROLOGY 1975; 32:808-13. [PMID: 173268 DOI: 10.1001/archneur.1975.00490540052006] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Three groups of 200-gm rats were injected subcutaneously with neostigmine methylsulfate (1 mg/kg/day) for 7, 30, and 100 days. Electrophysiological changes were assessed in vitro, using microelectrode techniques to examine diaphragm muscles of treated and untreated animals. Miniature end-plate potential (MEPP) amplitude decreased in neostigmine-treated preparations. Guanidine hydrochloride enhances transmitter release and increases MEPP frequency in control preparations. Neostigmine-treated animals examined between 6 to 72 hours after discontinuation of neostigmine therapy showed impaired response to the facilitating influence of guanidine. Recovery of response to guanidine was inversely related to length of treatment with neostigmine. Results of electron-microscopic examination of motor end-plates in treated animals revealed ultrastructural changes, including simplified end-plates, and, occasionally, multiple, separate, junctional regions. Therefore, the chronic administration of cholinesterase inhibitors in man may have a deleterious effect, as well as a transient beneficial one.
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Gertz SD, Rennels ML, Forbes MS. Preparation of vascular endothelium for scanning electron microscopy: a comparison of the effects of perfusion and immersion fixation. J Microsc 1975; 105:309-13. [PMID: 772214 DOI: 10.1111/j.1365-2818.1975.tb04065.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
A comparison of currently used methods of tissue fixation for scanning electron microscopic study of vascular endothelium revealed that in situ fixation by intravascular perfusion is superior to immersion for the preservation of endothelial surface morphology.
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43
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Forbes MS, Sperelakis N. The "imaged-desmosome": a component of intercalated discs in embryonic guinea pig myocardium. Anat Rec (Hoboken) 1975; 183:243-57. [PMID: 1200401 DOI: 10.1002/ar.1091830203] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
A heretofore undescribed structural variation of the desmosomes of the intercalated disc is found in myocardial cells of the embryonic guinea pig. These desmosomes consist of the usual pair of opaque leaflets, each of the pair contributed by one of the apposed muscle cells. In addition, in the cytoplasm of one of the cells there appears a pair of linear densities (facsimile-lines) parallel to the nearest desmosomal plaque and separated from it by a 60 mm space. The facsimile lines superficially resemble the desmosomal leaflets in length and thickness, thus forming a cytoplasmic "image" of the desmosome. These "imaged-desmosomes" are found predominantly in the longitudinally-running portions of the intercalated discs and are common in 7-week embryos. Their incidence drops sharply by eight weeks of gestation, and they are virtually absent from the heart of the newborn animal. Often tubules of the sarcoplasmic reticulum (SR) are found in apposition to the facsimile-lines; thus it appears that association of SR tubules with desmosomes is responsible for the formation of imaged-desmosomes.
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Forbes MS, Dent JN, Singhas CA. The developmental cytology of the nuptial pad in the red-spotted newt. Dev Biol 1975; 46:56-78. [PMID: 1158027 DOI: 10.1016/0012-1606(75)90087-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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45
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Sperelakis N, Forbes MS, Shigenobu K, Coburn S. Organ-cultured chick embryonic hearts of various ages. II. Ultrastructure. J Mol Cell Cardiol 1974; 6:473-83. [PMID: 4431048 DOI: 10.1016/0022-2828(74)90028-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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46
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Forbes MS, Dent JN. Filaments and microtubules in the gonadotrophic cell of the lizard, Anolis carolinensis. J Morphol 1974; 143:409-33. [PMID: 4852046 DOI: 10.1002/jmor.1051430405] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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47
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Forbes MS, Sperelakis N. Spheroidal bodies in the junctional sarcoplasmic reticulum of lizard myocardial cells. J Cell Biol 1974; 60:602-15. [PMID: 4824288 PMCID: PMC2109240 DOI: 10.1083/jcb.60.3.602] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
The sarcoplasmic reticulum (SR) of lizard (Anolis carolinensis) myocardial cells has been examined, with particular attention being paid to the structural details of the peripheral couplings (junctional SR). Spheroidal bodies are present within the opaque core of junctional SR; these can be seen both in sections made en face and in sections cut to show the apposition of the junctional SR with the sarcolemma. Opaque junctional processes extend between the sarcolemma and the peripheral junctional SR. The myocardial cells in addition contain some SR cisternae deep within the cells which also possess opaque cores composed of spheroids. Although the significance of the junctional SR spheroidal bodies is unknown, it is thought that they could act as a matrix on which enzymes such as calcium-specific ATPase may be located.
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48
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Forbes MS, Zaccaria RA, Dent JN. Developmental cytology of chromatophores in the red-spotted newt. THE AMERICAN JOURNAL OF ANATOMY 1973; 138:37-71. [PMID: 4741500 DOI: 10.1002/aja.1001380104] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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49
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Dent JN, Eng LA, Forbes MS. Relations of prolactin and thyroid hormone to molting, skin texture, and cutaneous secretion in the red-spotted newt. THE JOURNAL OF EXPERIMENTAL ZOOLOGY 1973; 184:369-82. [PMID: 4708140 DOI: 10.1002/jez.1401840311] [Citation(s) in RCA: 47] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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50
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Forbes MS, Sperelakis N. A labyrinthine structure formed from a transverse tubule of mouse ventricular myocardium. J Cell Biol 1973; 56:865-9. [PMID: 4347212 PMCID: PMC2108933 DOI: 10.1083/jcb.56.3.865] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
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