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Barniville G, Hartigan PJ, Lydon A, Rawas O, Andrews JF, Donne B, Kelly M, Brady C, McNamara B, Taylor D, Ishtiaq A, Glacken P, O’brien M, Moraes D, Tyrrell J, McCormack PME, Feely J, Stinson J, Hemeryck L, Feely J, Chan R, Hemeryck L, Clancy L, Feely J, Sharma SC, Barry-Kinsella C, Cortell E, Harrison RF, O’connor JJ, Trout SJ, Kruk ZL, Sharma SC, Barry-Kinsella C, Foran K, Han B, Kelly JP, O’donnell JM, Hollywood MA, McHale NG, Kearns JB, Hardiman O, Harris AM, Harris CS, O’halloran KD, Bradford A, McKeogh D, Nolan P, O’regan RG, McDermott M, Maddineni VR, Mirakhur RK, Cooper AR, Clarke RSJ, O’brien W, Tarpey J, Cooney C, Blunnie WP, Moriarty DC, Niveditha Y, O’donovan DJ, Manning B, Furlong E, Martin F, Brazil DP, Smyth EM, Keenan AK, Nunan N, Faustman D, Li X, Sklar RM, Brown RH, O’gorman S, Bannigan J, Moynihan JB, Staunton HP, Breathnach CS, Lynch L, Bowen M, Malone L, Cunningham AJ, Armstrong NC, Allen JM, Strain JJ, McDermott BM, Strain JJ, Bailey CJ, Flatt PR, Megaw DP, Murphy FJ, Reen DJ, D’arcy G, Cooke T, Sheahan R, Foley D, Reilly M, Jauch W, Gibney M, Crean P, Gearty G, Walsh M, McGinley J, Hurley J, Phelan D, Neligan M, Luckwill RG, O’connor JJ, Rowan MJ, Anwyll R, Wall M, Houghton JA, Heatley M, Whiteside C, Maxwell P, Toner P, Walsh DM, Lowe AS, Baxter GD, Allen JM, Bell AJ, Lee TC, McNamara BP, Prendergast PJ, Taylor D, Campion DP, Leek BF. Royal academy of medicine in Ireland section of biomedical sciences. Ir J Med Sci 1992. [DOI: 10.1007/bf02983772] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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252
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McClatchey AI, McKenna-Yasek D, Cros D, Worthen HG, Kuncl RW, DeSilva SM, Cornblath DR, Gusella JF, Brown RH. Novel mutations in families with unusual and variable disorders of the skeletal muscle sodium channel. Nat Genet 1992; 2:148-52. [PMID: 1338909 DOI: 10.1038/ng1092-148] [Citation(s) in RCA: 93] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Mutations in the skeletal muscle sodium channel gene (SCN4A) have been described in paramyotonia congenita (PMC) and hyperkalaemic periodic paralysis (HPP). We have found two mutations in SCN4A which affect regions of the sodium channel not previously associated with a disease phenotype. Furthermore, affected family members display an unusual mixture of clinical features reminiscent of PMC, HPP and of a third disorder, myotonia congenita (MC). The highly variable individual expression of these symptoms, including in some cases apparent non-penetrance, implies the existence of modifying factors. Mutations in SCN4A can produce a broad range of phenotypes in muscle diseases characterized by episodic abnormalities of membrane excitability.
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Muise KL, Duchon MA, Brown RH. Effect of angular traction on the performance of modern vacuum extractors. Am J Obstet Gynecol 1992; 167:1125-9. [PMID: 1415403 DOI: 10.1016/s0002-9378(12)80053-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
OBJECTIVE Our objective was to describe the effect of off-axis traction on the performance of modern vacuum extractors. STUDY DESIGN Eight vacuum extractors were examined in the laboratory with a force indicator and fetal cephalic model. Devices evaluated included the 6 cm Malmstrom, Mity-Vac, M-Type, O'Neil, Posterior, Silc, Tender-Touch, and silicone elastomer. Maximal tractive force (pop-off) was measured for each device at 10-degrees increments from the vertical. RESULTS Multivariate regression analysis described the best model as follows: Maximal tractive force = Constant + Angle + Vacuum (p < 0.05). The partial regression coefficients for angle were negative in all devices except the Posterior cup. At increasing angles of off-axis traction, maximal tractive force decreased in the following order: Silc, silicone elastomer, Tender-Touch, M-Type, Mity-Vac, O'Neill, Malmstrom, and Posterior. CONCLUSIONS Application of oblique traction resulted in a linear decline in maximal tractive force. An understanding of in vitro performance may allow tailoring of cup selection to the clinical situation.
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Byrd GT, Brown RH, Bouton JH, Bassett CL, Black CC. Degree of C(4) Photosynthesis in C(4) and C(3)-C(4)Flaveria Species and Their Hybrids : I. CO(2) Assimilation and Metabolism and Activities of Phosphoenolpyruvate Carboxylase and NADP-Malic Enzyme. PLANT PHYSIOLOGY 1992; 100:939-46. [PMID: 16653079 PMCID: PMC1075647 DOI: 10.1104/pp.100.2.939] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
The degree of C(4) photosynthesis was assessed in four hybrids among C(4), C(4)-like, and C(3)-C(4) species in the genus Flaveria using (14)C labeling, CO(2) exchange, (13)C discrimination, and C(4) enzyme activities. The hybrids incorporated from 57 to 88% of the (14)C assimilated in a 10-s exposure into C(4) acids compared with 26% for the C(3)-C(4) species Flaveria linearis, 91% for the C(4) species Flaveria trinervia, and 87% for the C(4)-like Flaveria brownii. Those plants with high percentages of (14)C initially fixed into C(4) acids also metabolized the C(4) acids quickly, and the percentage of (14)C in 3-phosphoglyceric acid plus sugar phosphates increased for at least a 30-s exposure to (12)CO(2). This indicated a high degree of coordination between the carbon accumulation and reduction phases of the C(4) and C(3) cycles. Synthesis and metabolism of C(4) acids by the species and their hybrids were highly and linearly correlated with discrimination against (13)C. The relationship of (13)C discrimination or (14)C metabolism to O(2) inhibition of photosynthesis was curvilinear, changing more rapidly at C(4)-like values of (14)C metabolism and (13)C discrimination. Incorporation of initial (14)C into C(4) acids showed a biphasic increase with increased activities of phosphoenolpyruvate carboxylase and NADP-malic enzyme (steep at low activities), but turnover of C(4) acids was linearly related to NADP-malic enzyme activity. Several other traits were closely related to the in vitro activity of NADP-malic enzyme but not phosphoenolpyruvate carboxylase. The data indicate that the hybrids have variable degrees of C(4) photosynthesis but that the carbon accumulation and reduction portions of the C(4) and C(3) cycles are well coordinated.
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Brown RH, Byrd GT, Black CC. Degree of C(4) Photosynthesis in C(4) and C(3)-C(4)Flaveria Species and Their Hybrids : II. Inhibition of Apparent Photosynthesis by a Phosphoenolpyruvate Carboxylase Inhibitor. PLANT PHYSIOLOGY 1992; 100:947-50. [PMID: 16653080 PMCID: PMC1075648 DOI: 10.1104/pp.100.2.947] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Hybrids have been made between species of Flaveria exhibiting varying levels of C(4) photosynthesis. The degree of C(4) photosynthesis expressed in four interspecific hybrids (Flaveria trinervia [C(4)] x F. linearis [C(3)-C(4)], F. brownii [C(4)-like] x F. linearis, and two three-species hybrids from F. trinervia x [F. brownii x F. linearis]) was estimated by inhibiting phosphoenolpyruvate carboxylase in vivo with 3,3-dichloro-2-dihydroxyphosphinoylmethyl-2-propenoate (DCDP). The inhibitor was fed to detached leaves at a concentration of 4 mm, and apparent photosynthesis was measured at atmospheric levels of CO(2) and at 20 and 210 mL L(-1) of O(2). Photosynthesis at 210 mL L(-1) of O(2) was inhibited 32% by DCDP in F. linearis, by 60% in F. brownii, and by 87% in F. trinervia. Inhibition in the hybrids ranged from 38 to 52%. The inhibition of photosynthesis by 210 mL L(-1) of O(2) was increased when DCDP was used, except in the C(4) species, F. trinervia, in which photosynthesis was insensitive to O(2). Except for F. trinervia, control plants with less O(2) sensitivity (more C(4)-like) exhibited a progressively greater change in O(2) inhibition of photosynthesis when treated with DCDP. This increased O(2) inhibition probably resulted from decreased CO(2) concentrations in bundle sheath cells due to inhibition of phosphoenolpyruvate carboxylase. The inhibition of photosynthesis by DCDP is concluded to underestimate the degree of C(4) photosynthesis in the interspecific hybrids because increased direct assimilation of atmospheric CO(2) by ribulose bisphosphate carboxylase may compensate for inhibition of phosphoenolpyruvate carboxylase.
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Brown RH, Treasure ET. Inequities in oral health: implications for the delivery of care and health promotion. THE NEW ZEALAND DENTAL JOURNAL 1992; 88:132-8. [PMID: 1484642] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
This paper has summarised data showing that inequities in oral health and the receipt of oral health care exist in New Zealand. We submit that these inequities, and the consequences of oral ill-health, are of such seriousness that they cannot be ignored. Overcoming barriers to oral ill health and barriers to dental care will be a complex task. Although much can be done by the dental providers and their organisations, there is need for oral ill health to be viewed within the overall context of inequity and disadvantage within society.
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Byrd GT, Sage RF, Brown RH. A Comparison of Dark Respiration between C(3) and C(4) Plants. PLANT PHYSIOLOGY 1992; 100:191-8. [PMID: 16652945 PMCID: PMC1075536 DOI: 10.1104/pp.100.1.191] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Lower respiratory costs were hypothesized as providing an additional benefit in C(4) plants compared to C(3) plants due to less investment in proteins in C(4) leaves. Therefore, photosynthesis and dark respiration of mature leaves were compared between a number of C(4) and C(3) species. Although photosynthetic rates were generally greater in C(4) when compared to C(3) species, no differences were found in dark respiration rates of individual leaves at either the beginning or after 16 h of the dark period. The effects of nitrogen on photosynthesis and respiration of individual leaves and whole plants were also investigated in two species that occupy similar habitats, Amaranthus retroflexus (C(4)) and Chenopodium album (C(3)). For mature leaves of both species, there was no relationship between leaf nitrogen and leaf respiration, with leaves of both species exhibiting a similar rate of decline after 16 h of darkness. In contrast, leaf photosynthesis increased with increasing leaf nitrogen in both species, with the C(4) species displaying a greater photosynthetic response to leaf nitrogen. For whole plants of both species grown at different nitrogen levels, there was a clear linear relationship between net CO(2) uptake and CO(2) efflux in the dark. The dependence of nightly CO(2) efflux on CO(2) uptake was similar for both species, although the response of CO(2) uptake to leaf nitrogen was much steeper in the C(4) species, Amaranthus retroflexus. Rates of growth and maintenance respiration by whole plants of both species were similar, with both species displaying higher rates at higher leaf nitrogen. There were no significant differences in leaf or whole plant maintenance respiration between species at any temperature between 18 and 42 degrees C. The data suggest no obvious differences in respiratory costs in C(4) and C(3) plants.
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Hardiman O, Brown RH, Beggs AH, Specht L, Sklar RM. Differential glucocorticoid effects on the fusion of Duchenne/Becker and control muscle cultures: pharmacologic detection of accelerated aging in dystrophic muscle. Neurology 1992; 42:1085-91. [PMID: 1579232 DOI: 10.1212/wnl.42.5.1085] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
We report that the glucocorticoid methylprednisolone (Mepd) enhanced myogenesis in normal primary human muscle cultures, but inhibited myogenesis of most Duchenne/Becker muscle cultures. A decline in the magnitude of myogenic stimulation of Mepd correlated with age in a random group of control patients, including some with neurologic diseases other than Duchenne/Becker dystrophy. A case of Duchenne muscular dystrophy from an exceptionally young patient yielded a muscle culture that was myogenically stimulated by Mepd. These results suggest that continuous cycles of degeneration and regeneration of dystrophic muscle in vivo may result in a change of the glucocorticoid response of the muscle progenitor cells. The glucocorticoid effects suggest caution in the long-term clinical use of these agents for muscle disease such as Duchenne muscular dystrophy.
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259
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Thomson WM, Brown RH, Williams SM. Dentures, prosthetic treatment needs, and mucosal health in an institutionalised elderly population. THE NEW ZEALAND DENTAL JOURNAL 1992; 88:51-5. [PMID: 1495633] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
A survey of 359 elderly residents of rest homes and geriatric hospitals in the Manawatu and Horowhenua regions showed that 80.5 percent were fully edentulous. Full upper and lower dentures were worn by 64 percent of the total sample, and 31 percent of the dentate group wore one or more partial dentures. Prosthetic treatment needs were dominated by full dentures: 18 percent of upper dentures and 26 percent of lower dentures were considered to need replacement. A further 24 percent of full lower dentures required relining. Only 7 percent of the dentures were named. One third of the subjects had mucosal lesions, the most common lesions being angular cheilitis (present in 18 percent of subjects), traumatic ulcers (14 percent), atrophic glossitis (12 percent), and leukoplakia (present in 8 percent of subjects). No malignant lesions were found.
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260
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King TV, Clark RN, Calvin WM, Sherman DM, Brown RH. Evidence for Ammonium-Bearing Minerals on Ceres. Science 1992; 255:1551-3. [PMID: 17820166 DOI: 10.1126/science.255.5051.1551] [Citation(s) in RCA: 131] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Spectra obtained from recent telescopic observation of 1-Ceres and laboratory measurements and theoretical calculations of three component mixtures of Ceres analog material suggest that an ammoniated phyllosilicate is present on the surface of the asteroid, rather than H(2)O frost as had been previously reported. The presence of an ammoniated phyllosilicate, most likely ammoniated saponite, on the surface of Ceres implies that secondary temperatures could not have exceeded 400 kelvin.
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261
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McClatchey AI, Van den Bergh P, Pericak-Vance MA, Raskind W, Verellen C, McKenna-Yasek D, Rao K, Haines JL, Bird T, Brown RH. Temperature-sensitive mutations in the III-IV cytoplasmic loop region of the skeletal muscle sodium channel gene in paramyotonia congenita. Cell 1992; 68:769-74. [PMID: 1310898 DOI: 10.1016/0092-8674(92)90151-2] [Citation(s) in RCA: 163] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Paramyotonia congenita (PMC), a dominant disorder featuring cold-induced myotonia (muscle stiffness), has recently been genetically linked to a candidate gene, the skeletal muscle sodium channel gene SCN4A. We have now established that SCN4A is the disease gene in PMC by identifying two different single-base coding sequence alterations in PMC families. Both mutations affect highly conserved residues in the III-IV cytoplasmic loop, a portion of the sodium channel thought to pivot in response to membrane depolarization, thereby blocking and inactivating the channel. Abnormal function of this cytoplasmic loop therefore appears to produce the Na+ current abnormality and the unique temperature-sensitive clinical phenotype in this disorder.
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Small S, Ali HH, Lennon VA, Brown RH, Carr DB, de Armendi A. Anesthesia for an unsuspected Lambert-Eaton myasthenic syndrome with autoantibodies and occult small cell lung carcinoma. Anesthesiology 1992; 76:142-5. [PMID: 1309626 DOI: 10.1097/00000542-199201000-00022] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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263
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Rojas CV, Wang JZ, Schwartz LS, Hoffman EP, Powell BR, Brown RH. A Met-to-Val mutation in the skeletal muscle Na+ channel alpha-subunit in hyperkalaemic periodic paralysis. Nature 1991; 354:387-9. [PMID: 1659668 DOI: 10.1038/354387a0] [Citation(s) in RCA: 238] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
HYPERKALAEMIC periodic paralysis (HYPP) is an autosomal dominant disease that results in episodic electrical inexcitability and paralysis of skeletal muscle. Electrophysiological data indicate that tetrodotoxin-sensitive sodium channels from muscle cells of HYPP-affected individuals show abnormal inactivation. Genetic analysis of nine HYPP families has shown tight linkage between the adult skeletal muscle sodium channel alpha-subunit gene on chromosome 17q and the disease (lod score, z = 24; recombination frequency 0 = 0), strongly suggesting that mutations of the alpha-subunit gene cause HYPP. We sequenced the alpha-subunit coding region isolated from muscle biopsies from affected (familial HYPP) and control individuals by cross-species polymerase chain reaction-mediated complementary DNA cloning. We have identified an A----G substitution in the patient's messenger RNA that causes a Met----Val change in a highly conserved region of the alpha-subunit, predicted to be in a transmembrane domain. This same change was found in a sporadic case of HYPP as a new mutation. We have therefore discovered a voltage-gated channel mutation responsible for a human genetic disease.
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264
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Herold CJ, Brown RH, Mitzner W, Links JM, Hirshman CA, Zerhouni EA. Assessment of pulmonary airway reactivity with high-resolution CT. Radiology 1991; 181:369-74. [PMID: 1924774 DOI: 10.1148/radiology.181.2.1924774] [Citation(s) in RCA: 59] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The evaluation of airway reactivity plays a central role in the diagnosis of bronchial hyperreactivity and asthma. The authors used high-resolution computed tomography (HRCT) to assess airway reactivity and compared the results with simultaneously performed measurements of airway pressure (Paw). Ten anesthetized and ventilated dogs were studied in a control state, after saline aerosol application, and after histamine aerosol challenge. In each condition, Paw was determined and HRCT was performed at functional residual capacity. On the HRCT scans, the cross-sectional areas of airway lumina were measured by using a computer edging process. After histamine challenge, HRCT demonstrated a decrease in airway areas of 43% +/- 2% (mean +/- standard error) from baseline (control) and Paw increased 99% +/- 18%. Surprisingly, saline aerosol challenge also resulted in a significant decrease in airway areas (26% +/- 3%) from control, while Paw measurements did not change significantly. Airway reactivity varied between dogs and within dogs. The authors conclude that HRCT can depict the site and degree of airway reactions and thus represents a new tool to assess airway reactivity in vivo.
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265
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Brown RH, Byrd GT, Black CC. Assessing the degree of c(4) photosynthesis in c(3)-c(4) species using an inhibitor of phosphoenolpyruvate carboxylase. PLANT PHYSIOLOGY 1991; 97:985-9. [PMID: 16668540 PMCID: PMC1081113 DOI: 10.1104/pp.97.3.985] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
An analog of phosphoenolpyruvate, 3,3-dichloro-2-dihydroxyphosphinoylmethyl-2-propenoate (DCDP), was used to inhibit phosphoenolpyruvate carboxylase and, therefore, assess the contribution of the C(4) pathway to photosynthesis in detached leaves of several C(3)-C(4) intermediate species. There was no effect of 4 millimolar DCDP on apparent photosynthesis or on inhibition of apparent photosynthesis by 210 milliliters per liter of O(2) for the C(3)-C(4) species Panicum milioides, Moricandia arvensis, and Neurachne minor or the C(3) species Flaveria pringlei. However, when leaves of Flaveria linearis (C(3)-C(4)), Flaveria brownii (C(4)-like), and Flaveria trinervia (C(4)) were fed 4 millimolar DCDP, photosynthesis was reduced 32, 60, and 90%, respectively. Photosynthetic inhibition by 210 milliliter per liter of O(2) was also significantly increased in 4 millimolar DCDP-fed leaves of F. linearis and F. brownii but not in F. trinervia when compared with control values. These results with DCDP clearly demarcate C(3)-C(4) species into species including Panicum, Moricandia, and Neurachne whose reduced photorespiration occurs without any C(4) photosynthetic involvement and species of Flaveria in which C(4) photosynthesis contributes to CO(2) assimilation.
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266
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Brown RH. Allies in dental health. THE NEW ZEALAND DENTAL JOURNAL 1991; 87:127-30. [PMID: 1780104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Groups and individuals within the community, for a variety of reasons, have difficulty in attaining and maintaining oral health and in obtaining needed oral health care. Dentists themselves have limited opportunities for reaching these people. There are, however, occupational groups in frequent contact with them, able to influence their oral health positively and to facilitate the obtaining of treatment. Better liaison with these groups, and utilisation of their networks, will be an effective means of oral health promotion.
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267
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Thomson WM, Brown RH, Williams SM. Dental status and treatment needs of a New Zealand institutionalised elderly population. THE NEW ZEALAND DENTAL JOURNAL 1991; 87:119-23. [PMID: 1780102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
A survey of 359 elderly residents of rest homes and geriatric hospitals in the Manawatu and Horowhenua districts showed that approximately two-thirds were aged 80 or over, and 19.5 percent were dentate, with a mean 13.3 teeth per dentate subject. A mean of 4.6 teeth per dentate subject had caries of either the crown or root, or both. Older males had substantially higher extraction requirements than other subjects. The periodontal needs of the sample were generally low and dominated by the need for calculus removal.
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268
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Kotzar GM, Davy DT, Goldberg VM, Heiple KG, Berilla J, Heiple KG, Brown RH, Burstein AH. Telemeterized in vivo hip joint force data: a report on two patients after total hip surgery. J Orthop Res 1991; 9:621-33. [PMID: 1870027 DOI: 10.1002/jor.1100090502] [Citation(s) in RCA: 143] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Two telemeterized femoral components were implanted in two patients as part of normal total hip replacement procedures. The two components were instrumented to measure the three force components directed along: (a) the neck axis, (b) transverse to the neck axis and in the plane of the prosthesis, and (c) transverse to the neck axis and perpendicular to the plane of the prosthesis. Data were collected at multiple sessions during the early postoperative period for a number of standard activities, including gait, stair climbing, rising from a chair, single leg stance, double leg stance, ipsilateral and contralateral straight leg lifts while supine, ipsilateral flexion and extension while standing, and ipsilateral abduction while standing and lying on the contralateral side. These data are summarized and compared with the published results from analytic studies and with the results from previous studies using instrumented femoral components. Peak loads for gait during the period of study were roughly 2.7 body weights (BW) when the patients walked at their normal pace. Contact forces at the hip during stationary single leg stance approximated the peak loads during gait with values ranging from 2.1 to 2.8 BW. The highest forces recorded reached values approaching 5.5 BW and occurred during periods of instability while the patient engaged in stationary single leg stance. Our in vivo data indicate that forces generated during the above activities increase in magnitude quite rapidly during the early postoperative period and that during this period the patients have the ability to perform the activities of daily living without generating the high amplitude joint contact forces suggested by the results of dynamic studies. Joint contact forces during gait were found to depend on speed, but the high absolute magnitudes predicted by model studies were not supported by the in vivo data.
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Brown RH, Herold CJ, Hirshman CA, Zerhouni EA, Mitzner W. In vivo measurements of airway reactivity using high-resolution computed tomography. THE AMERICAN REVIEW OF RESPIRATORY DISEASE 1991; 144:208-12. [PMID: 2064130 DOI: 10.1164/ajrccm/144.1.208] [Citation(s) in RCA: 75] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Changes in airway resistance are reported to account for only a portion of changes in total lung resistance. The fraction of total lung resistance caused by airway resistance is difficult to quantify in vivo. High-resolution computed tomography (HRCT) has potential application for directly measuring changes in airway size in vivo. In the present investigation, we studied five anesthetized mongrel dogs using HRCT to locate and measure changes in airway area after aerosol histamine challenge in the absence and presence of deep inspiration. We also related changes in total lung resistance to changes in airway area. We found that in all dogs after histamine aerosol challenge, airway area decreased (range, 23 +/- 7 to 67 +/- 5%, mean +/- SEM), and total lung resistance increased (range, 191 to 378%). After deep inspiration (equal to three times tidal volume), four of the five dogs showed further significant decreases in airway area (range, 13 +/- 6 to 71 +/- 8%), whereas all five dogs showed decreases in RL (range, 3 to 35%). The fact that preconstricted airways constricted further after deep inspiration while the measured RL decreased suggests that RL may not always be a reliable indicator of changes in the size of conducting airways larger than 1 mm.
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Sklar RM, Hudson A, Brown RH. Glucocorticoids increase myoblast proliferation rates by inhibiting death of cycling cells. IN VITRO CELLULAR & DEVELOPMENTAL BIOLOGY : JOURNAL OF THE TISSUE CULTURE ASSOCIATION 1991; 27A:433-4. [PMID: 1869481 DOI: 10.1007/bf02631138] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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271
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Cannon SC, Brown RH, Corey DP. A sodium channel defect in hyperkalemic periodic paralysis: potassium-induced failure of inactivation. Neuron 1991; 6:619-26. [PMID: 1849724 DOI: 10.1016/0896-6273(91)90064-7] [Citation(s) in RCA: 161] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Hyperkalemic periodic analysis (HPP) is an autosomal dominant disorder characterized by episodic weakness lasting minutes to days in association with a mild elevation in serum K+. In vitro measurements of whole-cell currents in HPP muscle have demonstrated a persistent, tetrodotoxin-sensitive Na+ current, and we have recently shown by linkage analysis that the Na+ channel alpha subunit gene may contain the HPP mutation. In this study, we have made patch-clamp recordings from cultured HPP myotubes and found a defect in the normal voltage-dependent inactivation of Na+ channels. Moderate elevation of extracellular K+ favors an aberrant gating mode in a small fraction of the channels that is characterized by persistent reopenings and prolonged dwell times in the open state. The Na+ current, through noninactivating channels, may cause the skeletal muscle weakness in HPP by depolarizing the cell, thereby inactivating normal Na+ channels, which are then unable to generate an action potential. Thus the dominant expression of HPP is manifest by inactivation of the wild-type Na+ channel through the influence of the mutant gene product on membrane voltage.
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272
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Brown RH. Combination therapy. THE CLAO JOURNAL : OFFICIAL PUBLICATION OF THE CONTACT LENS ASSOCIATION OF OPHTHALMOLOGISTS, INC 1991; 17:135-6. [PMID: 1675596] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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273
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Abstract
The oral and facial manifestations of pycnodysostosis (Maroteaux-Lamy syndrome) are reviewed, and illustrated by a case in which the presenting feature was delayed and ectopic eruption of permanent teeth.
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274
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Abstract
Internal heat flow from radioactive decay in Triton's interior along with absorbed thermal energy from Neptune total 5 to 20 percent of the insolation absorbed by Triton, thus comprising a significant fraction of Triton's surface energy balance. These additional energy inputs can raise Triton's surface temperature between approximately 0.5 and 1.5 K above that possible with absorbed sunlight alone, resulting in an increase of about a factor of approximately 1.5 to 2.5 in Triton's basal atmospheric pressure. If Triton's internal heat flow is concentrated in some areas, as is likely, local effects such as enhanced sublimation with subsequent modification of albedo could be quite large. Furthermore, indications of recent global albedo change on Triton suggest that Triton's surface temperature and pressure may not now be in steady state, further suggesting that atmospheric pressure on Triton was as much as ten times higher in the recent past.
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Parker SD, Brown RH, Hirshman CA. Differential effect of glucocorticoids on pulmonary responses and eosinophils. RESPIRATION PHYSIOLOGY 1991; 83:323-31. [PMID: 2052760 DOI: 10.1016/0034-5687(91)90051-j] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The persistent airway hyperresponsiveness of Basenji-Greyhound (BG) dogs to 10% citric acid (CA) is abolished by chronic administration of methylprednisolone (MP) and is accompanied by the disappearance of eosinophils from the bronchoalveolar lavage (BAL) fluid. To determine whether the disappearance of eosinophils from BAL fluid was temporally related to the loss of airway responsiveness to CA, we investigated the time course of the reduction in airway responsiveness to CA and correlated it with changes in cell profiles in BAL fluid in a group of BG dogs treated with MP for 1 to 7 days. Six dogs in separate studies were pretreated with MP (2 mg/kg/day) subcutaneously for either 1, 3 or 7 days. Each dog served as its own control for each set of studies. Under thiopental anesthesia, lung resistance (RL) was calculated from transpulmonary pressure and flow measurements prior to and 5 minutes following the completion of a 10% CA aerosol. BAL was performed on a separate occasion with the animals pretreated with MP for either 1, 7, 10 or 14 days. Baseline RL was not significantly different in each control and treatment group. The pulmonary response to CA challenge was diminished following 1, 3 and 7 days of MP pretreatment. Although eosinophils disappeared from the peripheral blood following 1 day of MP treatment, eosinophils in BAL did not begin decreasing until 10 days of MP pretreatment. This temporal dissociation between CA hyperresponsiveness and eosinophils in the BAL fluid suggests that epithelial damage by toxic products of eosinophils in the airway lumen does not play a direct role in citric acid induced airway hyperresponsiveness in BG dogs.
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