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Schneible PA, Young RB. Leucine pools in normal and dystrophic chicken skeletal muscle cells in culture. J Biol Chem 1984. [DOI: 10.1016/s0021-9258(17)43425-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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Chan JC, Young RB, Alon U, Mamunes P. Hypercalcemia in children with disorders of calcium and phosphate metabolism during long-term treatment with 1,25-dihydroxyvitamin-D3. Pediatrics 1983; 72:225-33. [PMID: 6688127] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
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Iscoe S, Young RB, Jennings DB. Control of respiratory pattern in conscious dog: effects of heat and CO2. JOURNAL OF APPLIED PHYSIOLOGY: RESPIRATORY, ENVIRONMENTAL AND EXERCISE PHYSIOLOGY 1983; 54:623-31. [PMID: 6404872 DOI: 10.1152/jappl.1983.54.3.623] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
We measured tidal volume (VT) and inspiratory (TI) and expiratory (TE) durations in five conscious tracheostomized dogs breathing air or 5% CO2 in air either at normal (20 degrees C) or elevated (30 degrees C) ambient temperatures. Respiratory frequency ranged between 16 and 333/min due to changes in both TI and TE. During panting TI exceeded TE. During air inhalation instantaneous ventilation (V) spontaneously ranged from 100 to 1,600 ml . kg-1 . min-1. Hypercapnia, heat stress, or both, increased this range of V by increasing maximum V, primarily due to increases in mean inspiratory flow. Under these conditions, changes in TI accounted for more of the spontaneous changes in breath duration. During inhalation of air and 5% CO2, a positive correlation between VT and TI was obtained for TI between 0.13 and 1.05 s; above 1.05 s VT decreased. Heat stress increased VT at a given TI. We suggest that either the decay rate or position of the inspiratory off-switch threshold curve (Clark and von Euler, J. Physiol. London 222: 267, 1972) varies in conscious dogs. Shifts in either the reset (onset) value or decay rate of the curve yield a positive correlation between VT and TI. This modification to the Clark-von Euler model implies that the primary effect of anesthesia on respiratory control is fixation of the inspiratory off-switch threshold curve.
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Tait GA, Young RB, Wilson GJ, Steward DJ, MacGregor DC. Myocardial pH during regional ischemia: evaluation of a fiber-optic photometric probe. THE AMERICAN JOURNAL OF PHYSIOLOGY 1982; 243:H1027-31. [PMID: 7149039 DOI: 10.1152/ajpheart.1982.243.6.h1027] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The relationship between the decrease in intramyocardial extracellular pH and the degree of stenosis of the left anterior descending (LAD) coronary artery was studied in eight dogs pretreated with propranolol. Intramyocardial pH was measured with a miniature glass pH electrode and with a new photometric pH probe that uses fiber-optic filaments to measure the color change of an indicator substance in a small permeable chamber. The LAD was cannulated and perfused from the axillary artery. Cannula flow was measured with an electromagnetic flow probe, and regional myocardial blood flow (RMBF) was measured with radioactive microspheres before and at the end of a period of critical stenosis, 2/3 reduction of flow, or total occlusion of the LAD cannula. In the region of the glass electrode, the mean RMBF (+/-SE) decreased by 16.3 +/- 3.3, 52.7 +/- 7.3, and 84.8 +/- 6.5% during the three levels of stenosis, and the pH correspondingly decreased by 0.05 +/- 0.01, 0.29 +/- 0.10, and 0.94 +/- 0.17 units. In the region of the photometric probe, the RMBF decreased 19.1 +/- 1.3, 47.2 +/- 6.7, and 84.3 +/- 6.0%, and the pH decreased by 0.05 +/- 0.02, 0.14 +/- 0.04, and 0.76 +/- 0.18 units. There was no statistically significant difference between the two types of pH sensor.
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Orcutt MW, Young RB. Cell differentiation, protein synthesis rate and protein accumulation in muscle cell cultures isolated from embryos of layer and broiler chickens. J Anim Sci 1982; 54:769-76. [PMID: 7085524 DOI: 10.2527/jas1982.544769x] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Muscle cell cultures were prepared from the leg muscle of 12-d layer and broiler chicken embryos. Cultures were then compared over a 10-d period from their capacity to differentiate into multinucleated myotubes and to synthesize and accumulate protein. Differentiation was qualitatively similar in the two cell types as evidenced by myoblast fusion that occurred rapidly during the first 2 d and remained essentially constant between d 3 and 10. However, several quantitative differences were observed. Even though the number of myotubes per culture was comparable between layers and broilers throughout development, layer muscle cultures usually exhibited a higher percentage fusion and more myonuclei per culture than broiler muscle cultures. Additionally, the nuclear density (i.e., the number of nuclei per myotube segment) was approximately 25% greater in layer cultures than in broilers between d 2 and 10 in culture. The rate of incorporation of 3H-leucine into total protein during pulse labeling experiments was comparable in muscle cultures of layers and broilers; however, broiler muscle cells accumulated approximately 40% more total protein per nucleus between d 6 and 10. Myosin heavy chain synthesis rate was higher in layer than in broiler muscle cultures, but broiler muscle cultures accumulated approximately 30% more myosin heavy chain than layers between d 6 and 10. The half-life of myosin heavy chain was 45 h in layer muscle cultures and 103 h in broiler muscle cultures. Thus, the capacity of broiler cells to accumulate more muscle protein was primarily due to a drastically slower protein breakdown rate.
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Young RB, Denome RM, Achtymichuk GW. Stimulation of myosin heavy chain synthesis in steady-state muscle cultures by the ionophore, A23187, requires transcription of messenger RNA. Eur J Cell Biol 1981; 26:184-7. [PMID: 6799295] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
After approximately one week in culture, embryonic chick skeletal muscle cells are at a steady state with respect to myosin heavy chain (MHC) concentration and synthesis rate. Muscle cells normally synthesize MHC at a maximum rate of 2.3 X 10 4 MHC/min/nucleus and contain approximately 3 X 10 7 MHC/nucleus. These cells also contain approximately 3500 copies/nucleus of MHC mRNA associated with polysomes and 1600 copies/nucleus of MHC mRNA localized in the nonpolysomal fraction. To determine if nonpolysomal MHC mRNA in mature muscle cultures could be recruited into active translation complexes when MHC synthesis was stimulated, muscle cultures were treated with the Ca 2+ ionophore, A23187 (0-1 micro M). The MHC synthesis rate was stimulated by 25 to 50% relative to stimulation of the rate of total protein synthesis in the presence of A23187, but this stimulation was blocked when 10 microgram/ml actinomycin D was also present. These results suggest that even though 30% of MHC mRNA is not actively engaged in MHC synthesis in mature muscle cultures, stimulation of MHC synthesis by A23187 results from transcription of new MHC mRNA rather than from utilization of pre-existing mRNA.
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McConnell DG, Young RB, Suelter CH. Normal and dystrophic embryonic chicken pectoralis muscle cultures: II. Ultrastructural comparison. Muscle Nerve 1981; 4:125-30. [PMID: 7207502 DOI: 10.1002/mus.880040208] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Ultrastructural comparison was made between dystrophic and normal chicken breast muscle cells which had been isolated from 12-day-old embryos and cultured for up to 14 days. All electron microscopic examinations were conducted in the absence of any knowledge as to the dystrophic or normal origin of the cells, or the day on which the cells had been harvested from culture. The same blind procedures were applied to attempts to reconstruct from electron micrographs the correct sequence of days for a particular experiment and to identify the origin of the cells as normal or dystrophic. No consistent differences between normal and dystrophic cells were apparent either in extent of differentiation, such as the formation of mature sarcomeres, or in degenerative properties, such as disintegrating mitochondria, lipid aggregations, or extracellular debris. In light of metabolic and developmental differences in these cultures, the absence of ultrastructural differences was attributed in part to the presence of cells with widely different degrees of integrity, differentiation, and degeneration in both normal and dystrophic cultures.
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Young RB, McConnell DG, Suelter CH, Phillips TA. Normal and dystrophic embryonic chicken pectoralis muscle cultures: I. Cell differentiation, protein synthesis, and enzyme levels. Muscle Nerve 1981; 4:117-24. [PMID: 6451804 DOI: 10.1002/mus.880040207] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Normal (line 200) and dystrophic (line 307) embryonic chicken pectoralis muscle cells were studied in cell culture over a period of 2 weeks. During the first 4 days, normal and dystrophic cultures exhibited similar developmental increases in the number of nuclei within multinucleated myotubes, however, dystrophic muscle cells degenerated approximately twice as fast as normal cells once the initial burst of myoblast fusion was complete. The apparent synthesis rate of nonmyofibrillar proteins was similar in normal aand dystrophic cells throughout development, but the apparent synthesis rates of myosin heavy chain and the myofibrillar protein fraction were 50%--90% higher in dystrophic muscle cultures once maturity had been reached (days 6--14). The specific activities of creatine kinase and phosphofructokinase were not affected by the dystrophic condition; however, specific activity of AMP-deaminase was depressed 25%--40% in the dystrophic muscle cultures.
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McConnell DG, Gardner ME, Tuomari AV, Young RB, Suelter CH. Normal and dystrophic embryonic chicken pectoralis muscle cultures: III. Viral infection of normal cell cultures. Muscle Nerve 1981; 4:131-6. [PMID: 6259523 DOI: 10.1002/mus.880040209] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Twelve-day normal and dystrophic chick embryo breast muscle cells were cultured for up to 14 days, using normal embryo extract in the culture medium. Fluorodeoxyuridine was added on day 3 to suppress fibroblast overgrowth. Three of 6 experiments with normal cells were severely infected with avian leucosis/sarcoma (ALS) virus particles. The findings appear to lend support to the suggestion that the ALS virus is a mitochondriophage. Infected cultures demonstrated a depressed rate of total protein synthesis as reflected by incorporation of [3H]leucine. Extractable protein and total protein content were also depressed within several days after ALS particles were identified. These findings reinforce caution in acceptance of the common assumption that viral infections are an unavoidable and metabolically benign component of muscle cell cultures.
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Young RB, Dombroske OC. Metabolism of myosin heavy chain in steady-state chick skeletal muscle cultures. Biochem J 1981; 194:241-7. [PMID: 7305978 PMCID: PMC1162737 DOI: 10.1042/bj1940241] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Synthesis, accumulation and breakdown of the 200000-mol.wt. heavy subunit of myosin were analysed over an 11 day period in muscle cell cultures isolated from the leg muscle of 12-day chick embryos. Muscle cells accumulated myosin heavy chain rapidly from days 2 to 5 and maintained a maximum, constant myosin-heavy-chain concentration between days 7 and 11. Myosin-heavy-chain content and breakdown rate were compared in steady-state muscle cultures grown either in the presence of an optimum batch of horse serum (control) or in the presence of horse serum that had been pre-selected for its ability to inhibit several-fold the rate of synthesis of myosin heavy chain (inhibitory). The quantity of myosin heavy chain in the inhibited cultures was decreased in direct proportion to the decrease in the rate of synthesis of myosin heavy chain; however, the half-lives of myosin heavy chain (control, 17.7h; inhibitory, 17.0h) were virtually identical. In contrast, the absolute rate of breakdown of myosin heavy chain, expressed as molecules/min per nucleus, was approx. 5-fold lower in the inhibited cultures (4.3 X 10(3) molecules/min per nucleus) than in the control cultures (21.7 X 10(3) molecules/min per nucleus). Thus, inhibition of myosin-heavy-chain synthesis in this case was accompanied by diminished myosin-heavy-chain concentration and absolute breakdown rate at the altered steady state, but relative myosin-heavy-chain breakdown rates were unchanged.
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Young RB, Orcutt M, Blauwiekel PB. Quantitative measurement of protein mass and radioactivity in N,N'-diallyltartardiamide crosslinked polyacrylamide slab gels. Anal Biochem 1980; 108:202-6. [PMID: 6450545 DOI: 10.1016/0003-2697(80)90713-7] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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Riebow JF, Young RB. Effect of leupeptin on protein turnover in normal and dystrophic chicken skeletal muscle cells in culture. BIOCHEMICAL MEDICINE 1980; 23:316-23. [PMID: 7417239 DOI: 10.1016/0006-2944(80)90042-3] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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Nykyforiak CJ, Young RB, Phillips TA. Changes in intracellular Ca2+ distribution during the transition of fibroblasts from the proliferating to the stationary state. Biochem Biophys Res Commun 1980; 93:583-7. [PMID: 7387661 DOI: 10.1016/0006-291x(80)91117-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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Allen RE, Merkel RA, Young RB. Cellular aspects of muscle growth: myogenic cell proliferation. J Anim Sci 1979; 49:115-27. [PMID: 500507 DOI: 10.2527/jas1979.491115x] [Citation(s) in RCA: 180] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
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Young RB, Bergen WG, Blauwiekel PB. Myosin synthesis in embryonic chicken fibroblasts. J Biophys Biochem Cytol 1979; 81:115-22. [PMID: 479285 PMCID: PMC2111524 DOI: 10.1083/jcb.81.1.115] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The rate of constitutive myosin synthesis was measured in cultures of replicating embryonic chicken skin fibroblasts by pulse labeling with [3H]leucine. These cells synthesized the 200,000-dalton heavy chain of myosin (MHC) at a rate of 3.2 x 10(3) molecules/cell/min. Additionally, an independent estimate of the MHC synthesis rate needed to maintain a constant level of constitutive MHC/cell was calculated from total protein content, percentage MHC, fibroblast doubling time, and MHC half-life. This calculated rate of approximately 2.9 x 10(3) molecules/cell/min was in close agreement with the measured rate. By comparison, the synthesis rate of myofibrillar MHC in fully activated muscle cell cultures was approximately 2.9 x 10(4) molecules/nucleus/min.
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Young RB, Allen RE. Transitions in gene activity during development of muscle fibers. J Anim Sci 1979; 48:837-52. [PMID: 383671 DOI: 10.2527/jas1979.484837x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
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Young RB, Miller TR, Merkel RA. Myofibrillar protein synthesis and assembly in satellite cell cultures isolated from skeletal muscle of mice. J Anim Sci 1979; 48:54-62. [PMID: 479020 DOI: 10.2527/jas1979.48154x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
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Gál EM, Young RB, Sherman AD. Tryptophan loading: consequent effects on the synthesis of kynurenine and 5-hydroxyindoles in rat brain. J Neurochem 1978; 31:237-44. [PMID: 307593 DOI: 10.1111/j.1471-4159.1978.tb12454.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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Heritage DW, English SC, Young RB, Chen AT. Cytogenetics of recurrent abortions. Fertil Steril 1978; 29:414-7. [PMID: 565723] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Chromosome banding studies were carried out on both partners of 37 couples who had had two or more spontaneous abortions. Three patients had chromosome disorders; one was a triple-X female and the other two (one male and one female) were t(13;14) translocation carriers. Review of the literature indicates that the over-all frequency of major chromosome disorders in couples with repeated abortions is 2.6%. About three-fourths of these disorders are reciprocal and Robersonian translocations.
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Young RB, Goll DE, Stromer MH. Isolation of myosin-synthesizing polysomes from cultures of embryonic chicken myoblasts before fusion. Dev Biol 1975; 47:123-35. [PMID: 1204927 DOI: 10.1016/0012-1606(75)90268-7] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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Stromer MH, Goll DE, Young RB, Robson RM, Parrish FC. Ultrastructural features of skeletal muscle differentiation and development. J Anim Sci 1974; 38:1111-41. [PMID: 4596891 DOI: 10.2527/jas1974.3851111x] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
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Young RB, Bryson MJ, Sweat ML, Street JC. Complexing of DDT and o,p'DDD with adrenal cytochrome P-450 hydroxylating systems. JOURNAL OF STEROID BIOCHEMISTRY 1973; 4:585-91. [PMID: 4789318 DOI: 10.1016/0022-4731(73)90033-2] [Citation(s) in RCA: 35] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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Rahal F, Young RB, Mamunes P. Gonadal dysgenesis associated with a multicystic kidney. AMERICAN JOURNAL OF DISEASES OF CHILDREN (1960) 1973; 126:505-6. [PMID: 4783664 DOI: 10.1001/archpedi.1973.02110190415012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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