351
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Tait RC, Walker ID, Islam SI, Mitchell R, Conkie JA, McCall F, Davidson JF. Age related changes in protein C activity in healthy adult males. Thromb Haemost 1991; 65:326-7. [PMID: 2048058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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352
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Cooper MW, Mitchell R, Lutherer LO, Lust R. Electrocardiography and postextrasystolic potentiation: utilization of the two methods to predict postrevascularization segmental myocardial function. Clin Cardiol 1991; 14:243-8. [PMID: 1707355 DOI: 10.1002/clc.4960140313] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
We previously reported that postextrasystolic potentiation (PESP) is a useful predictor of changes in systolic wall function (SWF) following coronary revascularization. In the current study we analyzed ECG changes related to corresponding myocardial segments to determine their correlation with PESP and SWF. We found: (1) The PESP response in a jeopardized segment was a valid predictor of improved SWF even when Q waves, ST-segment changes, or T-wave changes were present. (2) However, when Q waves were present in two or more of the corresponding leads, positive PESP was less likely to be observed. (3) Thus Q waves in two leads predicted the least postrevascularization improvement. (4) Segments with no corresponding Q-wave postrevascularization usually improved SWF. (5) Furthermore, a continuum of responsiveness to PESP was found, ranging from T-wave changes, ST-segment changes to Q-wave changes, indicating dissociation between electrical and mechanical events. In conclusion, the ECG together with PESP provide good predictive information relative to the efficacy of revascularization. PESP is a more valuable predictive indicator. ECG alone may be of value in that the occurrence of Q waves in two or more corresponding leads predicts a low probability of improved SWF. Further studies are indicated to investigate the dissociation between electrical and mechanical events.
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353
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Pope FM, Kendall BE, Slapak GI, Kapoor R, McDonald WI, Compston DA, Mitchell R, Hope DT, Millar-Craig MW, Dean JC. Type III collagen mutations cause fragile cerebral arteries. Br J Neurosurg 1991; 5:551-74. [PMID: 1772601 DOI: 10.3109/02688699109002878] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Premature vascular aneurysms and fragility of cerebral arteries are commonly associated with type III collagen mutations and physical signs suggesting a generalized abnormality of connective tissue. Sometimes these traits are clearly genetically transmitted. Here we present seven examples of early cerebrovascular aneurysms or fragility including five examples of carotid cavernous sinus aneurysms. With one exception in which we suspect the mutation is too small to be detected, all of them had easily visible abnormalities of their type III collagen proteins. Further work in progress will eventually allow the characterization of their mutations at gene sequence level and will be followed by the ability to prevent transmission of the mutant genes in these families.
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354
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Upcroft JA, Healey A, Mitchell R, Boreham PF, Upcroft P. Antigen expression from the ribosomal DNA repeat unit of Giardia intestinalis. Nucleic Acids Res 1990; 18:7077-81. [PMID: 2263466 PMCID: PMC332772 DOI: 10.1093/nar/18.23.7077] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The amitochondrial human intestinal parasite Giardia intestinalis is regarded to be the most ancient living example of single-celled eukaryotes and should display primitive features of pre-metazoan gene regulation. Characterization of E. coli clones which express Giardia antigens from plasmid vectors has revealed that an antigen is encoded by the rDNA repeat unit from the strand complementary to that encoding the rRNAs. The open reading frame (ORF) originates in the spacer region between the small (SS) and large (LS) subunit rRNA genes and terminates within the LS rRNA gene. The promoter region of this ORF has characteristics of both RNA polymerase (pol) II and pol III regulatory sequences, suggestive of gene regulation before these different promoter types evolved. The rDNA repeat unit is located on multiple chromosomal sites which are different in each isolate, although the electrophoretic karyotypes appear very stable in Giardia from both human and animal sources.
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355
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Hope PJ, Fleetwood-Walker SM, Mitchell R. Distinct antinociceptive actions mediated by different opioid receptors in the region of lamina I and laminae III-V of the dorsal horn of the rat. Br J Pharmacol 1990; 101:477-83. [PMID: 2175238 PMCID: PMC1917709 DOI: 10.1111/j.1476-5381.1990.tb12733.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
1. In view of the presence of mu, delta and kappa opioid receptors in the spinal dorsal horn and their apparent involvement in behavioural analgesia, the present experiments addressed the action of selective agonists ionophoresed in the vicinity of rat dorsal horn neurones which were located either in lamina I or in laminae III-V. 2. In laminae III-V, kappa agonists (U50488H and dynorphin A) caused a selective inhibition of the nociceptive responses of multireceptive cells, whilst mu and delta agonists [( D-Ala2, MePhe4, Gly-ol]enkephalin and [D-Pen2, D-Pen5]enkephalin respectively) failed to alter either the spontaneous activity or the response to noxious and innocuous cutaneous stimuli and to D,L-homocysteic acid or glutamate. Nocispecific neurones were encountered too rarely in laminae III-V to study their properties. 3. In lamina I, agonists had no effects on either nocispecific or multireceptive neurones. In contrast, the mu agonist [D-Ala2, MePhe4, Gly-ol]enkephalin consistently inhibited nociceptive responses of both multireceptive and nocispecific lamina I cells. The delta agonist [D-Pen2, D-Pen5]enkephalin consistently caused selective inhibition of the nociceptive responses of multireceptive cells but had a mixed profile of action on nocispecific cells. 4. These results suggest that mu, delta and kappa opioid receptors mediate different antinociceptive actions in both laminae III-V and lamina I. The study reveals a distinct physiological role for delta receptors in modulating nociceptive inputs to lamina I neurones. In contrast to mu and kappa receptor actions, delta receptors heterogeneously influence subpopulations of neurones.
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MESH Headings
- 3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cyclohexyl)-benzeneacetamide, (trans)-Isomer
- Analgesics/pharmacology
- Animals
- Electric Stimulation
- Enkephalin, Ala(2)-MePhe(4)-Gly(5)-
- Enkephalin, D-Penicillamine (2,5)-
- Enkephalins/pharmacology
- Neurons/drug effects
- Pain/physiopathology
- Pyrrolidines/pharmacology
- Rats
- Receptors, Opioid/drug effects
- Receptors, Opioid/physiology
- Receptors, Opioid, delta
- Receptors, Opioid, kappa
- Receptors, Opioid, mu
- Spinal Cord/physiology
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356
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Downing I, Templeton JG, Mitchell R, Fraser RH. A chemiluminescence assay for erythrophagocytosis. JOURNAL OF BIOLUMINESCENCE AND CHEMILUMINESCENCE 1990; 5:243-50. [PMID: 2123599 DOI: 10.1002/bio.1170050406] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
A luminol-dependent chemiluminescence assay for the assessment of the phagocytosis of erythrocytes sensitized with anti-D IgG immunoglobulin by mononuclear leukocytes is described. The mononuclear leukocytes were obtained by apheresis enriched by centrifugation through a density gradient and stored in liquid nitrogen before use. The total reaction mixture, consisting of mononuclear leukocytes-luminol-erythrocytes (either anti-D IgG sensitized or unsensitized controls) was 500 microliters, light detection was by an LKB 1251 luminometer. Peak luminescence was seen between 35-45 minutes, the reaction being exhausted by 120 minutes. Determination of the reproducibility of the assay gave intra- and inter-assay coefficients of variation of 5% and 13% respectively. We found the chemiluminescent response to be affected by the number of erythrocytes used in the assay and by the composition of the medium in which the cells were resuspended, particularly the pH at the initiation of the assay. We also compared the chemiluminescence assay to a microscopic phagocytic assay and found the results virtually identical. However, the former chemiluminescence assay was much easier to perform, marginally more sensitive, less laborious and eliminated any possibility of subjective error.
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357
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Healey A, Mitchell R, Upcroft JA, Boreham PF, Upcroft P. Complete nucleotide sequence of the ribosomal RNA tandem repeat unit from Giardia intestinalis. Nucleic Acids Res 1990; 18:4006. [PMID: 2374731 PMCID: PMC331122 DOI: 10.1093/nar/18.13.4006] [Citation(s) in RCA: 56] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
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358
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Mitchell R, MacEwan D, Johnson M, Thomson F. Pharmacology and cellular actions of protein kinase C isoforms. Eur J Pharmacol 1990. [DOI: 10.1016/0014-2999(90)92552-t] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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359
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Fleetwood-Walker SM, Mitchell R, Hope PJ, El-Yassir N, Molony V, Bladon CM. The involvement of neurokinin receptor subtypes in somatosensory processing in the superficial dorsal horn of the cat. Brain Res 1990; 519:169-82. [PMID: 1697775 DOI: 10.1016/0006-8993(90)90075-m] [Citation(s) in RCA: 94] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
As well as substance P (SP), neurokinin A (NKA) and neurokinin B (NKB) have recently been found in the superficial dorsal horn of the spinal cord; NKA originating mainly in fine primary afferents. We have investigated the effects of these tachykinins and a range of analogues on somatosensory responses of single identified dorsal horn neurons, when applied ionophoretically to the region of the substantia gelatinosa. Behavioural reflex tests of thermal nociception were carried out in parallel. The role of NK-1, NK-2 and NK-3 receptors was addressed. NK-1-selective agonists attenuated the non-nociceptive responses of identified multireceptive spinocervical tract (SCT) neurons. Of the endogenous tachykinins, both SP and NKB (a weak NK-1 agonist) showed this effect. No role for NK-3 receptors was identified in our experiments. NK-2-selective agonists (including NKA) caused a unique and selective facilitation of thermal nociceptive responses. NKA also reduced reflex response latency in tail-flick and hot plate tests. NKA as a primary afferent transmitter may thus be involved in mediating or facilitating the expression of thermal nociceptive inputs in the substantia gelatinosa. NKA and SP could be considered as acting in concert in the superficial dorsal horn in an effectively pro-nociceptive modulatory role. Evidence from receptor-selective antagonists supports that obtained with agonists for the roles of particular NK receptors in somatosensory processing. NK-2, but not NK-1 or NK-3 antagonists attenuated endogenous thermal nociceptive responses, supporting the hypothesis that an NK-2 agonist (such as NKA) may normally participate in expression of thermal nociception in the superficial dorsal horn. Behavioural experiments showing increased response latencies with a putative NK-2 selective antagonist further supported the involvement of NK-2 receptors in thermal nociception.
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360
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Mitchell R, MacEwan D, Johnson M, Dougan L, Bladon C. Biological activity of some thyrotrophin-releasing hormone analogues substituted at the 2 position. Biochem Soc Trans 1990; 18:433-4. [PMID: 2115462 DOI: 10.1042/bst0180433] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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361
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Abstract
Low-ionic-strength saline (LISS) techniques permit a safe and substantial reduction in incubation time and have therefore become the method of choice for antibody detection and compatibility testing in many transfusion laboratories. Consequently, the supply of reagent red cells (RBCs) in a low-ionic-strength preservative solution would remove the daily need for laboratories to wash and resuspend cells in LISS before use. However, the storage of fresh RBCs at low ionic strength in the presence of aminoglycoside antibiotics can cause a rapid loss of certain antigens, possibly as a result of the release of proteolytic enzymes from contaminating white cells. This article describes a low-ionic-strength solution that achieves preservation of antigens on liquid nitrogen-frozen-thawed RBCs for 21 days' storage at 4 degrees C.
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362
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MacEwan D, Mitchell R. Arachidonic acid acts through protein kinase C to inhibit depolarization-induced 45Ca2+ influx. Biochem Soc Trans 1990; 18:432-3. [PMID: 2115461 DOI: 10.1042/bst0180432a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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363
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Rising R, Maiorino PM, Mitchell R, Reid BL. The utilization of calcium soaps from animal fat by laying hens. Poult Sci 1990; 69:768-73. [PMID: 2367268 DOI: 10.3382/ps.0690768] [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: 12/31/2022] Open
Abstract
Ground wheat was employed as a carrier to evaluate the utilization by laying hens of animal fat, calcium soaps of fatty acids from animal fat (CS), and animal fat in the presence of 3.8% added calcium. Birds trained to consume their daily feed in two 1-h periods were fed ground wheat with 0, 3, 6, and 9% animal fat, CS, or 10% ground limestone and animal fat to provide 11 experimental diets. Animal fat and preformed CS were highly available to laying hens with total fatty acid availabilities of 100.2 +/- 1.2 (SE) and 99.2 +/- 3.6%, respectively, estimated by the regression of added fat on determined fat retentions. However, 3.8% calcium reduced animal-fat fatty acid availability to 86.3 +/- .7%. The true metabolizable energy of animal fat, as determined by regression from bomb-calorimetry data, was 9.63 +/- .58 kcal per g; a value of 9.36 kcal per g was obtained from fat-retention data [100.2% of the gross energy (GE) of 9.34 +/- .78 kcal per g]. With added limestone, the respective TME values were 9.36 +/- 1.30 kcal per g (regression) and 8.06 kcal per g (retention). The TME of the CS fatty acids was 7.20 +/- 1.05 kcal per g, estimated by regression; and the value calculated from CS fat retentions was 8.14 kcal per g, representing 99.2% of the GE (8.20 +/- .58 kcal per g). Discrepancies between calorimetric and fat-retention TME estimates represented animal-fat effects on wheat starch, fat, and amino-acid retentions.
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364
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Tait RC, Walker ID, Davidson JF, Islam SI, Mitchell R. Antithrombin III activity in healthy blood donors: age and sex related changes and prevalence of asymptomatic deficiency. Br J Haematol 1990; 75:141-2. [PMID: 2375917 DOI: 10.1111/j.1365-2141.1990.tb02635.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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365
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Sambrook PN, Shawe D, Hesp R, Zanelli JM, Mitchell R, Katz D, Gumpel JM, Ansell BM, Reeve J. Rapid periarticular bone loss in rheumatoid arthritis. Possible promotion by normal circulating concentrations of parathyroid hormone or calcitriol (1,25-dihydroxyvitamin D3). ARTHRITIS AND RHEUMATISM 1990; 33:615-22. [PMID: 2346517 DOI: 10.1002/art.1780330503] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
For approximately 2 years, bone loss was measured in women with early stages of rheumatoid arthritis (RA) and in control subjects, using serial computed tomography and dual photon absorptiometry. Rapid trabecular bone loss from the distal radius was observed in the RA patients but not the controls. The bone loss correlated with initial plasma levels of parathyroid hormone and 1,25-dihydroxyvitamin D3 (calcitriol) concentrations. It has been suggested that these humoral factors may interact with cytokines or other mediators produced in the adjacent wrist joint. Losses of the cortical bone of the radial midshaft and the lumbar spine were modest and were comparable in the 2 groups. Indices relating to both bone formation and bone resorption predicted bone loss at these 2 sites, but changes in the parathyroid hormone and calcitriol concentrations did not.
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366
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Upcroft P, Mitchell R, Boreham PF. DNA fingerprinting of the intestinal parasite Giardia duodenalis with the M13 phage genome. Int J Parasitol 1990; 20:319-23. [PMID: 2358315 DOI: 10.1016/0020-7519(90)90146-e] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
A DNA fingerprint procedure has been established for the intestinal parasite, Giardia duodenalis. This permits the identification of individual strains from both human and animal sources. Analysis of strain movement, resurgence and variation is now possible. The fingerprint probe is based on the tandem repetitive sequence found in bacteriophage M13 which hybridizes to a set of hypervariable polymorphic minisatellite sequences found in higher eukaryotes. This probe recognizes a weakly homologous set of hypervariable regions in the Giardia genome to provide a DNA fingerprint comparable to those seen in higher eukaryotes.
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367
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Fraser RH, Inglis G, Allan JC, Murphy MT, Allan EK, Mackie A, Mitchell R. Murine monoclonal antibody with anti-e-like specificity: suitability for screening for e-negative cells. Transfusion 1990; 30:226-9. [PMID: 2315996 DOI: 10.1046/j.1537-2995.1990.30390194342.x] [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: 12/31/2022]
Abstract
A directly agglutinating murine monoclonal antibody of the IgG3 isotype has been produced after mice were immunized with papain-treated Bombay phenotype, e-positive red cells (RBCs). The antibody strongly agglutinated all e-positive RBCs and gave negative reactions with RBCs from Rhnull persons and those homozygous for Rh deletion genes. Variable reactivity was found with e-negative RBCs, ranging from weak to negative with R2R2, slightly stronger with r"r", and stronger still with RzRz. These reactions, together with results from tests with a large panel of Rh-variant RBCs, suggested a specificity for an epitope that is part of the e mosaic but is also expressed at least partially on e-negative RBCs and is influenced by the presence of C. This antibody has been standardized for use as a screening reagent for R2R2 cells by a microplate technique, and over 6000 donations have been screened in this way. No discrepancies have been found in confirmatory tests for e-negative status using human anti-e.
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368
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Ribbans WJ, Mitchell R, Taylor GJ. Computerised arthrotomography of primary anterior dislocation of the shoulder. THE JOURNAL OF BONE AND JOINT SURGERY. BRITISH VOLUME 1990; 72:181-5. [PMID: 2312553 DOI: 10.1302/0301-620x.72b2.2312553] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Computerised arthrotomography was performed on 33 patients four to six weeks after acute primary anterior dislocation of the shoulder. Seventeen patients were under, and 16 over 50 years of age. Damage to the anterior glenoidal labrum was seen in all the younger patients and in 75% of the older ones. A large redundant capsular pouch, seen in the older patients, was present in 35% of the younger ones, and a posterior humeral head defect was seen in 82% of the younger patients and only 50% of the older. Associated fractures were more common in the older patients, and a tear of the rotator cuff was demonstrated in 63% of the older patients and in none of the younger ones.
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369
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Kelleher PW, Imperial ES, Burnett P, Mitchell R. Ventricular ectopy during prolonged ambulatory electrocardiographic monitoring in elderly hypertensive subjects. J Am Geriatr Soc 1990; 38:201-4. [PMID: 2312999 DOI: 10.1111/j.1532-5415.1990.tb03491.x] [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: 12/31/2022]
Abstract
To examine whether ventricular ectopy in hypertensive older people is associated with age, the hypertensive process, or treatment, a 24-hour ambulatory electrocardiogram recording was obtained in 94 noninstitutionalized subjects aged 60-90 years with isolated hypertension and 136 noninstitutionalized normotensive subjects aged 60-82 years. A significantly higher prevalence of frequent ventricular ectopic beats (VEB greater than 100 per recording) was found in hypertensive and normotensive groups age greater than or equal to 70 years compared to age 60-69 years (44% vs 15%, P less than .01, and 28% vs 9%, P less than 01, respectively). Complex ventricular ectopy was found to be significantly increased only in the hypertensive group greater than or equal to 70 years compared to 60-69 years (53% vs 28%, P less than .05). No significant difference for any type of ventricular ectopy was found between treated and untreated hypertensive subjects. Analysis of variance of frequent ventricular ectopy showed a significant effect of age (P less than .001) but not of hypertension. Multivariate regression analysis with frequent ventricular ectopy as the dependent variable confirmed this relationship. For complex ventricular ectopy, analysis of variance showed a significant effect of hypertension (P less than .001) and age (P less than .05). Multivariate regression analysis confirmed that complex ventricular ectopy was significantly associated with hypertension (P less than .01) and age (P less than .05). In elderly subjects aging alone is associated with increased frequency of ventricular ectopy, whereas complex ventricular ectopy is more significantly related to the hypertensive process than to age.
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370
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Mitchell R, Lambert A, Crosby SR, White A, Robertson WR. ACTH adrenal cell bioassay: improved sensitivity (12 ng/L) achieved by immunoextraction of ACTH from human plasma by a monoclonal antibody. Ann Clin Biochem 1990; 27 ( Pt 1):59-64. [PMID: 2155572 DOI: 10.1177/000456329002700112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
We have previously reported a bioassay for human plasma ACTH based upon trypsin dispersed guinea-pig adrenal cells which was sensitive to 100 ng/L ACTH in unextracted human plasma when measured against human pituitary ACTH (1-39) standard 74/555. We now present a bioassay of increased sensitivity (12 ng/L) which incorporates three major changes. The trypsin/trypsin inhibitor step in the cell dispersion protocol has been replaced with collagenase, donor calf serum (3%) has been incorporated into the standard curve and ACTH has been extracted from human plasma and dilutions of standard hormone by a sephacryl bound monoclonal antibody (2A3) directed towards the 25-39 sequence. The extracted standard curve has a detection limit of 6 ng/L and the cells can tolerate up to 50% plasma equivalent concentration. Thus, the improved assay has a detection limit of 12 ng/L ACTH in plasma. The assay can now measure bioactive plasma ACTH levels reliably in the normal range.
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371
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Mitchell R. Fundamentals of new food product development. Food Control 1990. [DOI: 10.1016/0956-7135(90)90124-u] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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372
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Tischer E, Gospodarowicz D, Mitchell R, Silva M, Schilling J, Lau K, Crisp T, Fiddes JC, Abraham JA. Vascular endothelial growth factor: a new member of the platelet-derived growth factor gene family. Biochem Biophys Res Commun 1989; 165:1198-206. [PMID: 2610687 DOI: 10.1016/0006-291x(89)92729-0] [Citation(s) in RCA: 203] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Using applications of the polymerase chain reaction (PCR) technique, cDNA clones have been isolated encoding bovine vascular endothelial growth factor (VEGF), a mitogen with specificity for vascular endothelial cells. Analysis of the clones indicates that VEGF can exist in two forms, probably due to alternative RNA splicing. The amino acid sequences predicted from the clones also show that VEGF shares homologies of about 21% and 24% respectively with the A and B chains of human platelet-derived growth factor (PDGF), and has complete conservation of the eight cysteine residues found in both mature PDGF chains. The homology is not reflected in function, however, since the cell types responsive to VEGF are distinct from those responsive to homo- and heterodimers of the PDGF chains.
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373
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Robertson WR, Lambert A, Mitchell R, Kendle K, Petrow V. The effect of some antiprostatic steroids upon cortisol production by guinea-pig adrenal cells stimulated by ACTH. Biochem Pharmacol 1989; 38:3669-71. [PMID: 2557025 DOI: 10.1016/0006-2952(89)90570-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The antiprostatic steroids 6-methylene-4-pregnene-3,20-dione (6-MP) (I), 17-alpha-acetoxy-6, 16-dimethylene-4-pregnene-3,20-dione (II), and melengestrol acetate (MGA) (III) were incubated with guinea-pig adrenal cells, both alone and maximally stimulated with ACTH. Cortisol output was then measured by RIA. Increased cortisol-like secretion was obtained with 6-MP in the absence of ACTH. In the presence of ACTH, cortisol-like steroid secretion was the sum of that seen with ACTH and 6-MP alone. It follows that 6-MP stimulates in vitro a cortisol-like steroid cross reacting with the cortisol antibody by a mechanism that by-passes ACTH. Steroid (II) weakly inhibited cortisol output. MGA, in contrast, proved to be a strong inhibitor of cortisol output (ID50 of 2.3 mumol/l). Its site of action was established by adding it to adrenal cells incubated with precursor steroids on the cortisol pathway. Conversion of 3 beta-hydroxysteroids to cortisol was inhibited whereas conversion of 3-keto steroids was not affected. It follows that MGA inhibits 3 beta-hydroxysteroid dehydrogenase.
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374
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375
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Brown MA, Child RP, O'Connor M, Williams G, Mitchell R. Pregnancy-induced hypertension and renal failure: clinical importance of diuretics, plasma volume and vasospasm. Aust N Z J Obstet Gynaecol 1989; 29:230-2. [PMID: 2604652 DOI: 10.1111/j.1479-828x.1989.tb01725.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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