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Zoltick JM, Picariello J, Stevenson M, Kipping B, Yaney S, Gardner L, Bedynek J. CORRELATION OF FITNESS PARAMETERS AND STANDARD CORONARY RISK FACTORS. Med Sci Sports Exerc 1985. [DOI: 10.1249/00005768-198504000-00366] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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327
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Stevenson M, Baillie AJ, Richards RM. Quantification of uptake of liposomal carboxyfluorescein by professional phagocytes in-vitro. A flow microfluorimetric study on the J774 murine macrophage cell line. J Pharm Pharmacol 1984; 36:824-30. [PMID: 6151975 DOI: 10.1111/j.2042-7158.1984.tb04885.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Unilamellar egg phosphatidylcholine/cholesterol liposomes containing carboxyfluorescein were prepared by an ether injection method. The ability of cells of the J774.2 murine macrophage cell line to incorporate the liposomal fluorophore during incubation at 37 degrees C was measured by flow microfluorimetry. Liposomes incorporating additional phosphatidylserine or phosphatidic acid were taken up much more avidly than those lacking these phospholipids and the greatest uptake of carboxyfluorescein was observed with the phosphatidylserine species. Calculation of the number of liposomes taken up, greater than or equal to 0.2% of the number given, showed that this was an inefficient process. However these uptake data support previous findings based on the intracellular bactericidal activity of liposomal antibiotics determined in an identical in-vitro system.
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Greenleaf NP, Stevenson M. ECONOMIC BELIEFS AND NURSES' WAGES: Sorting Fact from Fantasy. Nurs Forum 1984; 21:53-62. [PMID: 6567906 DOI: 10.1111/j.1744-6198.1984.tb01134.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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329
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Gervais F, Stevenson M, Skamene E. Genetic control of resistance to Listeria monocytogenes: regulation of leukocyte inflammatory responses by the Hc locus. THE JOURNAL OF IMMUNOLOGY 1984. [DOI: 10.4049/jimmunol.132.4.2078] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Abstract
The control mechanisms responsible for the innate resistance of C57BL/6J (B) mice and for the innate susceptibility of A/J (A) mice to infection with Listeria monocytogenes were studied by typing the recombinant inbred (RI) strains derived from these two progenitors for the trait of Listeria resistance/susceptibility. The strain distribution pattern (SDP) of this trait obtained in the 13 AXB/BXA RI strains studied suggests that an allelic difference at a major locus (Lr-1) is responsible for the trait of resistance/susceptibility to Listeria. In addition, another putative gene (Lr-2) unlinked to Lr-1 is postulated to control the level of bacterial load within the group of susceptible strains. The SDP of A and B alleles at the Lr-1 locus was fully concordant with that observed for the Hc locus (controlling the level of the C5 component of complement). This suggests that the genetic susceptibility of A strains of mice to Listeria infection is either directly due to or related to the C5 deficiency found in that strain. This conclusion is enhanced by the observation of a significant protection of A mice from listeriosis by the infusion of C5-rich serum. A survey of RI strains for the magnitude of PMN and macrophage inflammatory responses showed that the expression of both traits co-segregated and that the C5 deficiency was the major factor responsible for the defective inflammatory response of A strain mice. We conclude that a defect in the phagocyte inflammatory responses caused by C5 deficiency is the major reason for the extreme susceptibility of A mice to Listeria.
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330
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Gervais F, Stevenson M, Skamene E. Genetic control of resistance to Listeria monocytogenes: regulation of leukocyte inflammatory responses by the Hc locus. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 1984; 132:2078-83. [PMID: 6699408] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The control mechanisms responsible for the innate resistance of C57BL/6J (B) mice and for the innate susceptibility of A/J (A) mice to infection with Listeria monocytogenes were studied by typing the recombinant inbred (RI) strains derived from these two progenitors for the trait of Listeria resistance/susceptibility. The strain distribution pattern (SDP) of this trait obtained in the 13 AXB/BXA RI strains studied suggests that an allelic difference at a major locus (Lr-1) is responsible for the trait of resistance/susceptibility to Listeria. In addition, another putative gene (Lr-2) unlinked to Lr-1 is postulated to control the level of bacterial load within the group of susceptible strains. The SDP of A and B alleles at the Lr-1 locus was fully concordant with that observed for the Hc locus (controlling the level of the C5 component of complement). This suggests that the genetic susceptibility of A strains of mice to Listeria infection is either directly due to or related to the C5 deficiency found in that strain. This conclusion is enhanced by the observation of a significant protection of A mice from listeriosis by the infusion of C5-rich serum. A survey of RI strains for the magnitude of PMN and macrophage inflammatory responses showed that the expression of both traits co-segregated and that the C5 deficiency was the major factor responsible for the defective inflammatory response of A strain mice. We conclude that a defect in the phagocyte inflammatory responses caused by C5 deficiency is the major reason for the extreme susceptibility of A mice to Listeria.
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Abstract
The impetus to study sleep changes in a cluster population arose from a recent hypothesis that predicted the finding of sleep apnea in this disorder. It holds that cluster attacks may occur in response to oxygen desaturation. Proposed mechanisms involve impairment of carotid body activity secondary to hypothalamic-vasomotor regulatory dysfunction. Five chronic and five episodic cluster patients underwent nocturnal polysomnography, utilizing standard equipment for monitoring sleep status, cardiac activity, nasal and buccal air flow change, chest and abdominal breathing, muscle activity and oxygen saturation. All episodic patients and one of five chronic patients were found to have sleep apnea (60%). Mean apneas per hour during NREM sleep were similar to that of REM sleep; 26.7 and 28.2, respectively. Six patients with sleep apnea experienced 14 cluster headache attacks during the study period. Eight attacks (57%) followed episodes of oxygen desaturation ranging from 65% to 85%. In the sleep apnea group, 8 out of 14 attacks (57%) were associated with REM; three without, and five following oxygen desaturation. Of the non-apnea group, all of whom had chronic cluster headache, none of 5 attacks were associated with oxygen desaturation, and only 2/5 attacks occurred in relation to REM. Thus, our study showed that sleep apnea was a common finding in a randomly selected group of episodic cluster patients; and most nocturnal attacks were preceded by oxyhemoglobin desaturation and REM-related. These findings were uncommon in the chronic cluster group.
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Stevenson M, Baillie AJ, Richards RM. An in-vitro model of intracellular bacterial infection using the murine macrophage cell line J774.2. J Pharm Pharmacol 1984; 36:90-4. [PMID: 6143812 DOI: 10.1111/j.2042-7158.1984.tb03000.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
A simple model of intracellular bacterial infection based on the ability of the macrophage cell line J774.2 to phagocytose Escherichia coli in a reproducible manner is described. Viable counting of intracellular bacteria and microscopic examination of infected macrophage cultures after treatment with fluorescent E. coli antibody showed that the bacteria multiplied within the J774.2 cells. Viable intracellular bacteria may be used to study the activity of bactericidal and bacteriostatic drugs within the macrophage. The low apparent intracellular bactericidal activity of streptomycin, which was time- and concentration-dependent, accords with a low permeability of the J774.2 macrophages to this antibiotic. An exclusively intracellular infection could be achieved by inactivation of non-phagocytosed extracellular bacteria by streptomycin treatment of infected macrophage cultures. Under appropriate conditions intracellular bacterial viability was unaffected.
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333
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Stevenson M. Tuberculosis in the north--a lifestyle issue. THE CANADIAN NURSE 1984; 80:41-3. [PMID: 6557838] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/05/2023]
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334
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Abstract
Strain variation in the level of resistance to malaria was investigated in inbred mice after infection with Plasmodium chabaudi. Following intraperitoneal infection with the typing dose of parasitized erythrocytes, mice of 11 inbred strains could be separated using survival time as the criterium into resistant and susceptible groups. Genetic analysis of F1 hybrid and backcross progeny derived from one of the most resistant (B10.A) and from the most susceptible (A/J) strains as parents suggested that host resistance in this strain combination was genetically controlled by a dominant, non-H-2-linked, autosomal gene or closely linked genes. Analysis of the mechanisms of resistance to P chabaudi showed (1) phenotypic expression of the resistance gene was apparent within 6 days of infection as a significant difference between resistant and susceptible mice in the level of parasitemia; (2) the level of host NK cell activity was not related to the level of host resistance to malaria; (3) compared with susceptible A/J mice, resistant B10.A hosts had an augmented erythropoietic response during the course of malaria as well as during phenylhydrazine-induced anemia and (4) treatment with BCG or P acnes resulted in an equal degree of protection, measured by parasitemia and survival, in both resistant and susceptible mice.
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Stevenson M, Baillie AJ, Richards RM. Enhanced activity of streptomycin and chloramphenicol against intracellular Escherichia coli in the J774 macrophage cell line mediated by liposome delivery. Antimicrob Agents Chemother 1983; 24:742-9. [PMID: 6362555 PMCID: PMC185936 DOI: 10.1128/aac.24.5.742] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Streptomycin and chloramphenicol were entrapped within large neutral or anionic unilamellar vesicles of egg phosphatidylcholine prepared by an ether injection method. Both antibiotics in liposomal form were inactive against Escherichia coli in a simple tube dilution assay. A comparison was made of the activities of the free and liposomal forms of the antibiotics against E. coli located within the macrophages of the J774.2 murine cell line. The apparent intracellular antibacterial activity of both antibiotics was increased more than 10-fold by entrapment in neutral liposomes and in the case of chloramphenicol in anionic liposomes containing phosphatidylserine. Anionic liposomes containing phosphatidic acid were much less effective carriers than neutral liposomes for either antibiotic in this in vitro system. Incubation at 4 degrees C of cells with liposomes containing antibiotic or carboxyfluorescein inhibited intracellular antibacterial activity and cell-associated fluorescence. The high intracellular activity of the liposomal antibiotics is consistent with their phagocytic uptake by the macrophages followed by intracellular liposomal degradation and antibiotic release. Liposomal modification of cellular uptake and intracellular distribution of antibiotics may be used to extend the activity of existing and new agents against intracellular infection of the reticuloendothelial system.
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Abstract
Cloacal examination to determine sex was carried out in 145 penguins of five species. The birds were from four of the major collections in the British Isles. Differences in the appearance of the urodaeum were sufficient to differentiate between the sexes in the species examined.
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Stevenson M. Patients--a virtue? THE ULSTER MEDICAL JOURNAL 1983; 52:19-30. [PMID: 6397891 PMCID: PMC2448021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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338
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339
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Serjeant GR, Sommereux AM, Stevenson M, Mason K, Serjeant BE. Comparison of sickle cell-beta0 thalassaemia with homozygous sickle cell disease. Br J Haematol 1979; 41:83-93. [PMID: 420738 DOI: 10.1111/j.1365-2141.1979.tb03684.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Clinical and haematological features in 41 patients with sickle cell-beta0 thalassaemia (Sbeta0 thalassemia) and in 123 age--sex matched controls with homozygous sickle cell (SS) disease were compared. Persistence of splenomegaly was more common and fetal loss less common in Sbeta0 thalassemia but other clinical features were similar in the two genotypes. Total haemoglobin, Hb A2, PCV, CCV, and red cell count were significantly higher and MCV, MCH, MCHC, and ISC counts significantly lower in Sbeta0 thalassaemia. Proportional reticulocyte counts were significantly lower in Sbeta0 thalassaemia but there was no difference in absolute reticulocyte counts. Persistence of splenomegaly and low ISC counts are compatible with decreased intravascular sickling which may result from the lower mean cell haemoglobin S concentration in Sbeta0 thalassaemia. If beneficial effects of a low MCHC can be confirmed then a carefully monitored trial of iron deficiency in SS disease may be a logical experimental procedure.
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340
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Stevenson M, McGinty DJ. Polygraphic studies of kitten development: respiratory rate and variability during sleep-waking states. Dev Psychobiol 1978; 11:393-403. [PMID: 211061 DOI: 10.1002/dev.420110503] [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: 12/13/2022]
Abstract
The developmental course of respiration rate and variability during sleep states and waking was measured in chronically prepared kittens. Kittens had higher respiration rates during active sleep (AS) as compared to quiet sleep (QS) at all ages, with rates declining developmentally in both sleep states. Compared to waking, respiration rate and variability were decreased during sleep. The decrease was greatest in the youngest animals and during QS. Minute-to-minute respiratory variability declined from 10 to 40 days of age for each state, whereas breath-to-breath variability declined during the same period only during QS. Respiratory variability was higher in AS than QS in older kittens. Heart rate and variability were found to be correlated with respiratory parameters only during QS. These observations support the hypothesis that the control and development of respiration during sleep is achieved by different processes in QS and AS.
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McGinty DJ, Stevenson M, Hoppenbrouwers T, Harper RM, Sterman MB, Hodgman J. Polygraphic studies of kitten development: sleep state patterns. Dev Psychobiol 1977; 10:455-69. [PMID: 199512 DOI: 10.1002/dev.420100506] [Citation(s) in RCA: 33] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The sequence of developmental changes in sleep pattern organization was derived from 12-hr recordings in 10-, 20 and 40-day-old kittens. Each characteristic of sleep patterning exhibited a distinct maturational sequence. Earlier changes (10-20 days) included quiet sleep (QS) increments and somatic activity decrements; later changes (20-40 days) included emergence of EEG slow waves and spindles, decrements in active sleep (AS), and diminution of QS respiratory variability. Changes in the lengths of state epochs and the types of state transitions spanned the period studied. We suggest that the differential development of the characteristics of sleep patterns reflects differential maturation of distinct nervous system elements.
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342
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O'Dorisio TM, Cataland S, Stevenson M, Mazzaferri EL. Gastric inhibitory polypeptide (GIP). Intestinal distribution and stimulation by amino acids and medium-chain triglycerides. THE AMERICAN JOURNAL OF DIGESTIVE DISEASES 1976; 21:761-5. [PMID: 961670 DOI: 10.1007/bf01073027] [Citation(s) in RCA: 41] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Radioimmunoassayable gastric inhibitory polypeptide was measured in extracts of canine antrum, duodenum, jejunum, and ileum. The highest GIP concentrations were found in the duodenum (347 +/- 53 ng/g) and jejunum (300 +/- 68 ng/g). An immunochemical similarity was demonstrable between porcine GIP and canine GIP. Dogs prepared with Mann Bollman fistulae were given an amino acid (AA) mixture or medium-chain triglycerides (MTC) by intraduodenal perfusion. With AA, a peak mean serum concentration of 672 +/- 106 pg/ml was reached 15 min after starting the perfusion. MCT resulted in a peak mean serum GIP concentration of 504 +/- 55 pg/ml 30 min after beginning the perfusion. When compared to results previously reported from this laboratory, AA and MCT are not as potent as corn oil (long-chain triglyceride) or glucose in stimulating GIP release. We conclude: (1) Immunoassayable GIP concentrations are highest in the canine proximal small intestine. (2) AA and MCT are weak stimulants of GIP release in the dog.
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343
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Harden RM, Stevenson M, Lever R, Dunn W, Holroyd C, Wilson GM. Tape/slide programmes for independent study. Methods of presentation to students. BRITISH JOURNAL OF MEDICAL EDUCATION 1975; 9:170-5. [PMID: 54188] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Programmed audio tape/slide presentations have been presented to students by a variety of methods, (a) individual or pairs of students using automatic equipment in study booths; (b) students using simple portable equipment in or out of the learning centre; (c) groups of students in which discussion was encouraged; and (d) groups of students in which the student answered the questions individually without discussion. Each method has its advantages and disadvantages. With the exception of the groups without discussion, all were popular and chosen by a significant number of students as the method of choice. Automatic equipment in study booths was the most popular single method though the use of simple portable equipment had particular advantages. The majority of students prefer to have access to more than one method of presentation and attempts should be made to provide the learner with a variety of opportunities. The use of individual learning materials by groups of students should be further explored.
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344
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Marcus GJ, Stevenson M, Brown T. Alpha-methyldopa-induced immune thrombocytopenia. Report of case. Am J Clin Pathol 1975; 64:113-5. [PMID: 1155367 DOI: 10.1093/ajcp/64.1.113] [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: 12/25/2022] Open
Abstract
The clinical and laboratory features of a case of alphamethyldopa-induced thrombocytopenia are described. This is the second reported case in which the presence of alpha-methyldopa-induced platelet antibodies have been demonstrated.
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345
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Harden RM, Stevenson M, Downie WW, Wilson GM. Assessment of clinical competence using objective structured examination. BRITISH MEDICAL JOURNAL 1975; 1:447-51. [PMID: 1115966 PMCID: PMC1672423 DOI: 10.1136/bmj.1.5955.447] [Citation(s) in RCA: 772] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
To avoid many of the disadvantages of the traditional clinical examination we have introduced the structured clinical examination. In this students rotate round a series of stations in the hospital ward. At one station they are asked to carry out a procedure, such as take a history, undertake one aspect of physical examination, or interpret laboratory investigations in the light of a patient's problem, and at the next station they have to answer questions on the findings at the previous station and their interpretation. As they cannot go back to check on omissions multiple-choice questions have a minimal cueing effect. The students may be observed and scored at some stations by examiners using a check list. In the structured clinical examination the variables and complexity of the examination are more easily controlled, its aims can be more clearly defined, and more of the student's knowledge can be tested. The examination is more objective and a marking strategy can be decided in advance. The examination results in improved feed-back to students and staff.
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347
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Pringle CR, Duncan IB, Stevenson M. Isolation and characterization of temperature-sensitive mutants of vesicular stomatitis virus, New Jersey serotype. J Virol 1971; 8:836-41. [PMID: 4366429 PMCID: PMC376272 DOI: 10.1128/jvi.8.6.836-841.1971] [Citation(s) in RCA: 49] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Forty-eight temperature-sensitive (ts) mutants have been isolated from a wild-type strain of the New Jersey serotype of vesicular stomatitis virus (VSV) after exposure to the base analogue mutagen 5-fluorouracil. Of these mutants, 47 have been classified into 6 nonoverlapping complementation groups containing 21, 17, 4, 3, 2, and 1 mutant, respectively (1 mutant remaining unallocated). The ribonucleic acid (RNA) phenotype of 23 of these mutants has been established. Four of the six groups contain one or more mutants unable to synthesize detectable amounts of viral RNA under restrictive conditions (39 C). No complementation was observed in mixed infection with ts mutants from the five established complementation groups of the Indiana serotype of VSV.
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348
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Hughes-Jones NC, Stevenson M. The anti-D content of IgG preparations for use in the prevention of Rh haemolytic disease. Vox Sang 1968; 14:401-8. [PMID: 5693779 DOI: 10.1111/j.1423-0410.1968.tb01732.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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349
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Haygood RC, Stevenson M. Effects of number of irrelevant dimensions in nonconjunctive concept learning. JOURNAL OF EXPERIMENTAL PSYCHOLOGY 1967; 74:302-4. [PMID: 6048474 DOI: 10.1037/h0024597] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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350
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Abstract
The purpose of this study was to determine the effects of varying proportion of positive instances in the stimulus sequence over a wide range (0.1, 0.2, 0.4, 0.6, and 0.8). The results showed that number of trials to criterion generally increased as proportion of positive instances decreased. The function for number of errors was convex, however, reaching a maximum at 0.4 and decreasing toward the extremes. Detailed examination of the data disclosed that Ss in the 0.1 and 0.2 conditions were learning the probabilities and adopting a strategy of “when in doubt say no.” The effects were attributed in part to variation in information rates as proportion of positive instances changed and in part to differences in difficulty of utilization of information from positive and negative instances.
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