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Hart E, Ross P, Nelson J. Solving a real-world problem using an evolving heuristically driven schedule builder. EVOLUTIONARY COMPUTATION 1998; 6:61-80. [PMID: 10021741 DOI: 10.1162/evco.1998.6.1.61] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
This work addresses the real-life scheduling problem of a Scottish company that must produce daily schedules for the catching and transportation of large numbers of live chickens. The problem is complex and highly constrained. We show that it can be successfully solved by division into two subproblems and solving each using a separate genetic algorithm (GA). We address the problem of whether this produces locally optimal solutions and how to overcome this. We extend the traditional approach of evolving a "permutation + schedule builder" by concentrating on evolving the schedule builder itself. This results in a unique schedule builder being built for each daily scheduling problem, each individually tailored to deal with the particular features of that problem. This results in a robust, fast, and flexible system that can cope with most of the circumstances imaginable at the factory. We also compare the performance of a GA approach to several other evolutionary methods and show that population-based methods are superior to both hill-climbing and simulated annealing in the quality of solutions produced. Population-based methods also have the distinct advantage of producing multiple, equally fit solutions, which is of particular importance when considering the practical aspects of the problem.
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302
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Nelson J. Time to put the kettle on. ELDERLY CARE 1997; 9:36. [PMID: 9510698 DOI: 10.7748/eldc.9.6.36.s19] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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303
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Abstract
An epidemiological study of the mucopolysaccharidoses (MPS) in Northern Ireland using multiple ascertainment sources was carried out and the incidence rate for the period 1958-1985 was estimated. An incidence of approximately 1 in 76,000 live births was obtained for MPS 1H (Hurler phenotype); 1 in 280,000 for MPS 1 H/S (Hurler/Scheie phenotype); 1 in 140,000 live births (1 in 72,000 male live births) for MPS II (Hunter syndrome); 1 in 280,000 for MPS III (Sanfilippo syndrome) and 1 in 76,000 for MPS IV A (Morquio syndrome type A). No cases of MPS IS (Scheie phenotype), MPS IV B (Morquio syndrome type B) or MPS VI (Maroteaux-Lamy syndrome) were ascertained during the study period. Three cases of non-immune hydrops fetalis born to consanguineous parents were thought to be due to beta-glucuronidase deficiency (MPS VII) on the basis of placental histology and enzyme studies on both parents but no living cases of MPS VII were ascertained. The overall incidence for all types of mucopolysaccharidosis was approximately 1 in 25,000 live births. A comparison is made with incidence estimates obtained from other published studies.
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304
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Barroga CF, Ellis R, Nelson J, Heaton RK, Atkinson JH, McCutchan JA, Grant I, Spector SA. HIV-1 neurocognitive disorders and chemokine receptors. AIDS 1997; 11:1651-2. [PMID: 9365772] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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305
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Harrison LI, Dahl DR, Cline A, Chang SF, Machacek J, Nelson J, Kannianinen C, Purrington A. Pharmacokinetics and dose proportionality of beclomethasone from three strengths of a CFC-free beclomethasone dipropionate metered-dose inhaler. Biopharm Drug Dispos 1997; 18:635-43. [PMID: 9330783 DOI: 10.1002/(sici)1099-081x(199710)18:7<635::aid-bdd53>3.0.co;2-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
As part of a development program to offer alternatives to chlorofluorocarbon (CFC) containing metered-dose inhalers, beclomethasone dipropionate has been formulated in a CFC-free system at three strengths: 50, 100, and 200 micrograms/actuation ex valve. To measure serum levels and dose proportionality of the beclomethasone derived from beclomethasone dipropionate, 13 mild to moderate asthmatic patients received a single dose of eight inhalations from each strength according to a double-blind crossover design. Seven patients were studied over 4 h and six patients over 12 h. For the total doses of 400, 800, and 1600 micrograms studied over 12 h, Cmax and AUC increased in a ratio of 1:1.8:3.1. A good correlation was seen between the fine-particle mass delivered and the in vivo performance of the three strengths. From a clinical point of view, the predictable increases in serum levels with an increase in dose will permit the clinician to effectively titrate a patient with this product.
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306
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Rapoport JL, Giedd J, Kumra S, Jacobsen L, Smith A, Lee P, Nelson J, Hamburger S. Childhood-onset schizophrenia. Progressive ventricular change during adolescence. ARCHIVES OF GENERAL PSYCHIATRY 1997; 54:897-903. [PMID: 9337768 DOI: 10.1001/archpsyc.1997.01830220013002] [Citation(s) in RCA: 190] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
BACKGROUND There is controversy about progression in brain abnormalities in later-onset schizophrenia. This study looked for more striking progression in brain abnormalities during adolescence in a chronically ill, treatment-refractory sample of patients with childhood-onset schizophrenia who had had more prepsychotic developmental disturbance, but clinical and neurobiological characteristics similar to those of patients with treatment-refractory adult-onset schizophrenia who have poor outcome. METHODS Anatomic brain magnetic resonance images were obtained for 16 children and adolescents with onset of schizophrenia by 12 years of age and 24 temporally yoked, age- and sex-matched healthy controls. Subjects were scanned on initial admission and rescanned after 2 years with the identical equipment and measurement methods. RESULTS Childhood schizophrenics showed a significantly greater increase in ventricular volume than did controls, for whom ventricles did not increase significantly (analysis of variance, diagnosis x time, F = 16.1, P < .001). A significant decrease in midsagittal thalamic area was also seen for the schizophrenics (P = .03), which was unchanged at rescan for controls. These differential brain changes correlated significantly with each other and tended to be predicted by both prepsychotic developmental abnormality (Premorbid Assessment Scale, P = .06) and Brief Psychiatric Rating Scale at follow-up (P = .07). CONCLUSIONS More consistent progressive ventricular enlargement was seen during adolescence for this childhood-onset sample than has been reported for adult-onset populations. The brain imaging results support other clinical data showing both early and late deviations in brain development for at least this rare subgroup of treatment-refractory, very-early-onset schizophrenic patients.
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307
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Petrovitch H, Nelson J, Snowdon D, Davis DG, Ross GW, Li CY, White L. Microscope field size and the neuropathologic criteria for Alzheimer's disease. Neurology 1997; 49:1175-6. [PMID: 9339717 DOI: 10.1212/wnl.49.4.1175] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
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308
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Nelson J. Ban the bottle. West J Med 1997. [DOI: 10.1136/bmj.315.7111.822] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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309
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Nelson J, Smith M, Bittles AH. Consanguineous marriage and its clinical consequences in migrants to Australia. Clin Genet 1997; 52:142-6. [PMID: 9377802 DOI: 10.1111/j.1399-0004.1997.tb02534.x] [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: 02/05/2023]
Abstract
Marriage between close biological relatives is strongly favoured in many countries in Asia and Africa. Although substantial numbers of migrants from these regions are now living in Australia, little information is available either on the prevalence of consanguineous unions among migrants or on their clinical outcome. Data are presented on a range of generally rare autosomal recessive genetic disorders diagnosed in the children of parents of Eastern Mediterranean origin who attended Westmead Hospital, Sydney for genetic counselling during the period 1990 to 1994. The effects of parental consanguinity are assessed both in terms of the specific recessive disorders detected, and the perceived role of consanguineous marriage in the communities investigated.
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310
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Nelson J, Flaherty M, Grattan-Smith P. Gillespie syndrome: a report of two further cases. AMERICAN JOURNAL OF MEDICAL GENETICS 1997; 71:134-8. [PMID: 9217210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
We describe two unrelated patients with Gillespie syndrome (partial aniridia, cerebellar ataxia, and mental retardation). The typical presentation is the discovery of fixed dilated pupils in a hypotonic infant. The iris abnormality is specific and seems pathognomonic of Gillespie syndrome. It can be distinguished clinically from other forms of aniridia and a presumptive diagnosis of Gillespie syndrome can be made in the first months of life on the basis of the ocular findings. Neurological involvement includes marked motor delay, hypotonia, disabling ataxia, and usually mental retardation. Cerebral and cerebellar atrophy with white matter changes on MRI scan were present in our second patient suggesting that patients with Gillespie syndrome may have more extensive CNS involvement than previously described. The parents of this child were first cousins; thus Gillespie syndrome may be heterogeneous with autosomal recessive and autosomal dominant forms.
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311
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Wallace MR, Heaton RK, McCutchan JA, Malone JL, Velin R, Nelson J, Miller LK, Weiss PJ, Oldfield EC, Grant I. Neurocognitive impairment in human immunodeficiency virus infection is correlated with sexually transmitted disease history. Sex Transm Dis 1997; 24:398-401. [PMID: 9263360 DOI: 10.1097/00007435-199708000-00003] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
BACKGROUND AND OBJECTIVES Neurocognitive impairment is common in human immunodeficiency virus (HIV)-infected subjects. The relationship of sexually transmitted diseases to neurocognitive changes is unknown. GOAL To establish whether HIV-infected patients with a history of syphilis or gonorrhea have a higher rate of neurocognitive dysfunction. STUDY DESIGN Neurocognitive function was measured by a battery of quantitative tests in a 453-person HIV-infected cohort and a 219-person HIV-seronegative control group. Neurocognitive function was then correlated with histories of either syphilis or gonorrhea to assess for possible relationships between these sexually transmitted diseases and neurologic impairment. RESULTS Human immunodeficiency virus-infected subjects with a history of either syphilis or gonorrhea tended to perform worse on neurocognitive testing than their counterparts. This difference could not be explained by educational attainment, age, race or CD4 cell count, and was not noted in the HIV-uninfected control subjects. CONCLUSIONS Sexually transmitted diseases in HIV-infected subjects are correlated with neurocognitive impairment through an unidentified mechanism.
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312
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Wilson DB, Golding AB, Smith RA, Dafashy T, Nelson J, Smith L, Carlo DJ, Brostoff SW, Gold DP. Results of a phase I clinical trial of a T-cell receptor peptide vaccine in patients with multiple sclerosis. I. Analysis of T-cell receptor utilization in CSF cell populations. J Neuroimmunol 1997; 76:15-28. [PMID: 9184629 DOI: 10.1016/s0165-5728(97)00028-3] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
To identify a panel of multiple sclerosis patients (MS) for a phase I clinical trial of a T-cell receptor (TCR) peptide vaccine we characterized the T-cell populations present in the cerebrospinal fluids (CSF) of a large group of patients with respect to surface phenotype and state of activation, TCR beta chain utilization, features of the CDR3 junctional region, the extent of clonality and persistence of selected clonotypes over time. These CSF cell populations consist of approximately 60% CD4+ T-cells, half of which bear IL-2 receptors, indicating these activated T-cells may be part of the pathogenic process in MS. When these activated CD4+ T-cells were selectively expanded in IL-2/IL-4 supplemented cultures, an over-representation of several TCRV beta families was noted in 39/47 patients, the most frequent being V beta 6.5, V beta 6.7, V beta 2, V beta 5 and V beta 4. Biased expression of various members of the V beta 6 family was seen in 21 of this group of 39 patients. Clonal analysis of TCR beta 6 CDR3 sequences, revealed two notable features: clonal dominance and clonal persistence. CSF cells from two-thirds of MS patients contained a dominant clone comprising 50% or more of sequences and the same patient-specific clone could be shown to persist for up to 18 months. This clonal prevalence and over representation of V beta 6+TCR raises the possibility that immunization with a V beta 6 peptide vaccine may produce a regulatory immune response leading to a clinical benefit.
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Gold DP, Smith RA, Golding AB, Morgan EE, Dafashy T, Nelson J, Smith L, Diveley J, Laxer JA, Richieri SP, Carlo DJ, Brostoff SW, Wilson DB. Results of a phase I clinical trial of a T-cell receptor vaccine in patients with multiple sclerosis. II. Comparative analysis of TCR utilization in CSF T-cell populations before and after vaccination with a TCRV beta 6 CDR2 peptide. J Neuroimmunol 1997; 76:29-38. [PMID: 9184630 DOI: 10.1016/s0165-5728(97)00029-5] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
We report here the results of a phase I trial of a T-cell receptor (TCR) V beta 6 CDR2 region peptide vaccine in 10 patients with multiple sclerosis who showed biased over-representations of V beta 6 mRNA among T-cells in their cerebrospinal fluids (CSF). One group of 5 patients was immunized twice during a four week period with 100 micrograms of the TCRV beta 6 peptide 39-LGQGPEF LTYFQNEAQLEKS-58 emulsified in incomplete Freund's adjuvant (IFA); the second group of 5 MS patients received 300 micrograms of the same peptide in IFA over a similar time period. Patients were monitored for adverse events, immunogenicity of the peptide and changes in their CSF T-cell populations. The results indicate that this peptide was immunogenic (T-cell proliferation assays and recall DTH responses) in some of the patients, although none of the immunized patients produced detectable anti-peptide antibodies. More importantly, we show that the 5 patients treated with higher doses of the vaccine displayed a slight decrease in CSF cellularity, a lack of growth of CSF cells in cytokine supplemented expansion cultures that implies a significant absence of a subset of activated CD4 T-cells and a marked diminution in V beta 6 mRNA levels among T-cells in these cultures. By comparison, in 5 patients receiving the lower dosage of the vaccine, CSF cellularity was the same or slightly increased over pre-vaccination levels, CSF cells from 1 patient failed to grow in expansion cultures and cultured CSF cells from 2 patients underwent a change from an oligoclonal V beta 6 pattern to one that was more polyclonal. These results justify a more through exploration of the use of TCR peptide vaccines as a possible therapeutic treatment for MS.
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314
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Faustin D, Klein S, Spector IJ, Nelson J. Maternal perception of preterm labor: is it reliable? THE JOURNAL OF MATERNAL-FETAL MEDICINE 1997; 6:184-6. [PMID: 9172063 DOI: 10.1002/(sici)1520-6661(199705/06)6:3<184::aid-mfm13>3.0.co;2-i] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The objective of this study was to determine the reliability of maternal perception of uterine contractions and the influence of gestational age and maternal training on the perception level. Three hundred fifty patients at high risk for preterm delivery were followed from 20 to 35 weeks of gestation. The average maternal perception (79%) of contractions did not significantly vary as a function of gestational age. Four groups of women were identified according to the perception index (PI) defined as the ratio of contractions felt by the mother and the contractions documented by tocodynamometer. Within each group, the PI did not significantly vary during consecutive monitoring sessions, as the women become more familiar with self detection of uterine contractions (R < .65, P > .95). Twenty-one percent (+/-5%) of all preterm uterine contractions were not perceived by the pregnant women from 21 to 35 weeks. Thirty-two patients (9.1%) fail to perceive most or all uterine contractions while 189 (54%) detect most or all at any time during the study period.
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315
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Nelson J, Hagedorn ME. Federal Nursing Service Award. Rhythms of War: activation experiences during the Persian Gulf War. Mil Med 1997; 162:233-9. [PMID: 9110545] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Reserve military members and families require family support; however, support needs may increase in war. Stress may stem from entering active duty or change in family situations. This ethnographic study illuminates patterns of activation through deactivation of reserve military members, their families, family support personnel, and commanders during the Persian Gulf War. The sample included 59 individuals. Five themes were uncovered: (1) staying connected, (2) living with war, (3) fluctuating emotions, (4) refocus your sense of life, and (5) challenges of living the day-to-day. This study contributes to understanding family support experience from activation through deactivation. Recommendations are offered.
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316
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Stone KR, Walgenbach AW, Abrams JT, Nelson J, Gillett N, Galili U. Porcine and bovine cartilage transplants in cynomolgus monkey: I. A model for chronic xenograft rejection. Transplantation 1997; 63:640-5. [PMID: 9075831 DOI: 10.1097/00007890-199703150-00005] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Transplantation of discordant xenograft tissues usually results in antibody-mediated hyperacute rejection response. It has been speculated that because cartilage has a limited vascular, neural, and lymphatic supply, it might be immunologically privileged and may not undergo hyperacute or chronic rejection. Moreover, porcine and bovine cartilage were found to express very low amounts of alpha-galactosyl epitopes (Gal alpha1-3Gal beta1-4GlcNAc-R). To evaluate animal cartilage for possible human transplantation, xenograft meniscal cartilage was transplanted from pigs and cows into the suprapatellar pouches of six cynomolgus monkeys (group 1). In a second group of six monkeys (group 2), porcine meniscal cartilage and porcine articular cartilage plugs were evaluated. During the 2-month evaluation period in group 1, all monkeys displayed an extensive humoral response to the xenograft, as indicated by the increase in production of antibodies against bovine and porcine cartilage. Upon explant, all meniscal cartilage samples in this group demonstrated histological evidence of chronic rejection, including fibroplasia, encapsulation, mononuclear infiltrates, foreign body giant cells, and eosinophilic infiltrates. There was no difference between the response seen in untreated tissues and that seen in tissues treated with UV irradiation or ozone oxidation. In group 2, the menisci explanted after 1 month displayed extensive infiltration of eosinophils alone or eosinophils mixed with mononuclear cells. The mononuclear infiltrates consisted primarily of CD4+ and CD8+ T cells and of macrophages. The articular cartilage plugs demonstrated only a small area of fibrous encapsulation and leukocyte infiltration at the periphery. This study suggests that xenograft cartilage tissue does not appear to be immunoprivileged and is unsuitable for human implantation due to a chronic rejection mechanism, which is evident already within 1 month after transplantation. In addition, this study may serve as a general model for the primate immune response against xenografts in the absence of hyperacute rejection.
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317
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McDonald JS, Nelson J, Lenner KA, McLane ML, McFadden ER. Effects of the combination of skin cooling and hyperpnea of frigid air in asthmatic and normal subjects. J Appl Physiol (1985) 1997; 82:453-9. [PMID: 9049724 DOI: 10.1152/jappl.1997.82.2.453] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
To investigate whether reducing integumental temperature influences pulmonary mechanics and interacts with inhaling cold air, 10 normal and 10 asthmatic subjects participated in a three-part trial in which cooling the skin of the head and thorax and isocapnic hyperventilation of frigid air were undertaken as isolated challenges and then administered in combination. Integumental cooling for 30 min caused airway obstruction to develop in both populations [change in 1-s forced expiratory volume (delta FEV1) asthmatic subjects = 10% ; normal subjects = 6%)]. Hyperventilation, however, only affected the asthmatic subjects (delta FEV1 asthmatic subjects = 18%; normal subjects = 3%). In contrast to expectations, the combined challenge did not produce a summation effect (delta FEV1 asthmatic subjects = 21%; normal subjects = 7%). These data demonstrate that the skin of the trunk and head is cold sensitive and when stimulated causes similar degrees of bronchial narrowing in both normal subjects and patients with airway disease independent of any ventilatory effect. They also indicate that cooling of the skin does not add to the obstructive consequences of hyperpnea.
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318
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Serafini P, Batzofin J, Nelson J. O-013 Can we enhance the probability of pregnancy in IVF? Usefulness of uterine power doppler sonography (PDS) and embryo quality. Fertil Steril 1997. [DOI: 10.1016/s0015-0282(97)90646-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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319
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Gwara S, Nelson J. Botanical taxonomy and buggery in Browning's "Soliloquy of the Spanish Cloister". ANQ 1997; 10:30-32. [PMID: 11619510 DOI: 10.1080/08957699709600787] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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320
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Serafini P, Batzofin J, Nelson J. P-141 Assessment of uterine blood flow by single power doppler sonographic (PDS) study at the preovulatory time replaces conventional color doppler imaging (CDI) estimations. Fertil Steril 1997. [DOI: 10.1016/s0015-0282(97)90956-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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321
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Aitkin L, Nelson J, Shepherd R. Development of hearing and vocalization in a marsupial, the Northern Quoll, Dasyurus hallucatus. THE JOURNAL OF EXPERIMENTAL ZOOLOGY 1996; 276:394-402. [PMID: 8986045 DOI: 10.1002/(sici)1097-010x(19961215)276:6<394::aid-jez3>3.0.co;2-i] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The development of hearing was studied in the Northern Quoll, a nocturnal marsupial carnivore whose young are born into a pouch in an immature state after about 21 days in utero. Startle responses to noise bursts of 105 dB sound pressure level first appeared at 60 days after arrival in the pouch, but only to occasional stimuli; forelimb rather than whole body twitches were evoked. The latter were elicited regularly at 67 days onward. Auditory brainstem response (ABR) audiograms were measured during the period when startle responses first appeared. At 68 days responses were elicited between 1 and 16 kHz with thresholds in excess of 55 dB. At 81-88 days responses occurred over the adult range at lower thresholds than observed in the adult. The waveform of the ABR increased in complexity and decreased in latency during development. Pouch-young emitted acoustically well-defined isolation cells when separated from their mothers. Fourier analysis of these calls revealed peak energy at 8-11 kHz irrespective of the sex of the pouch-young. The isolation call first became evident at about 35 days, when the young were deliberately removed from the nipple, and ceased being emitted beyond about 80 days, some 5 or so days after the eyes open, when the young leave the pouch for substantial amounts of time. The spectrum of the call was similar at all ages within this 45 day period, and its peak frequency correlated closely with the best frequency in the adult quoll's ABR audiogram. At approximately 80 days of age the calls developed major low frequency components, similar to those measured in adult vocalizations, and the contributions of frequencies between 8-11 kHz waned in importance. The results indicate that the onset of hearing in quolls occurs at a relatively early time in the course of their development, but prior to this time the pouch-young emit characteristic isolation calls easily detectable by the mother.
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Aitkin L, Nelson J, Martsi-McClintock A, Swann S. Features of the structural development of the inferior colliculus in relation to the onset of hearing in a marsupial: the northern quoll, Dasyurus hallucatus. J Comp Neurol 1996; 375:77-88. [PMID: 8913894 DOI: 10.1002/(sici)1096-9861(19961104)375:1<77::aid-cne5>3.0.co;2-l] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The time course of synaptogenesis and the arrival and myelination of afferent connections were studied in the developing inferior colliculus (IC) of a marsupial, the Northern Quoll, and related to the onset of hearing and patency of peripheral auditory structures in that species. The quoll is born after 3 weeks of intrauterine growth and completes its development in a pouch for a further 80 days before weaning. Synaptic terminals in the IC at 9 days after arrival in the pouch were extremely rare and were associated with very low vesicle numbers. The number of synapses increased smoothly during pouch life, whereas the number of neurons with nucleoli fell over the same time period. The ratio of synapses to cells steadily increased from day 9 to day 63, then rapidly accelerated to day 73; a similar high ratio was observed in adults. Retrograde labeling from the IC of fibers projected from the medullary auditory nuclei, first observed on day 36, became progressively denser during pouch life. Myelination of lateral lemniscal fibers was absent on day 45, extremely sparse on day 54, and clear on day 63. Myelin sheaths were not observed within the IC electron microscopically until day 73. Examination of the peripheral auditory system revealed that until about day 40 the middle ear was fluid-filled, and middle ear structures were spongy. Between days 51 and 63 the middle ear cleared, the eardrum became shiny, and the ear canal became patent. The structural development of the IC is therefore very mature at the time hearing begins (67 days), and the last major anatomical change preceding hearing appears to be the opening of the external ear canal.
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323
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Nelson J, Scott WN, Allen WE, Wilson DJ, Harriott P, McFerran NV, Walker B. Murine epidermal growth factor peptide (33-42) binds to a YIGSR-specific laminin receptor on both tumor and endothelial cells. J Biol Chem 1996; 271:26179-86. [PMID: 8824265 DOI: 10.1074/jbc.271.42.26179] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
A laminin-antagonist peptide, comprising amino acids 33-42 of murine epidermal growth factor (mEGF-(33-42)), interacts with a breast cancer- and endothelial cell-associated receptor, which is specific for the laminin B1 chain sequence, CDPGYIGSR-NH2 (Lam.B1-(925-933)), and is immunologically similar to a previously described 67-kDa laminin receptor. In whole cell receptor assays, mEGF-(33-42), Lam. B1-(925-933), and laminin all have IC50 values for displacement of 125I-laminin in the range 1-5 nM. Cell attachment to solid-phase laminin is also blocked by all three ligands, but in contrast to the receptor assays, mEGF-(33-42) or Lam.B1-(925-933), while equipotent with each other, were less effective than laminin. The concentrations of the peptides required to produce half-maximal inhibition of attachment were in the range 230-390 nM, but those for laminin were 1000-fold lower, in the range 0.2-0.3 nM. Like laminin, solid-phase mEGF-(33-42) supports cell attachment, and this ability is blocked by anti-67-kDa receptor antibodies. Modeling studies suggest that both peptides present a tyrosyl and an arginyl residue on the same face of a right-handed helical fold with elliptical cross-section.
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324
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Morrison W, Nelson J. Betaseron: a breakthrough treatment for multiple sclerosis. THE CANADIAN NURSE 1996; 92:38-41. [PMID: 9118060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Multiple sclerosis (MS) is the most common cause of disability in young adults; in Canada, it affects 1 in 1,000 people. A chronic and complicated demyelinating autoimmune disorder of the central nervous system, MS has no known cure. Indeed, there has been no effective treatment until recently.
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Nelson J, Tang Y, Boutilier R. The effects of salinity change on the exercise performance of two Atlantic cod (Gadus morhua) populations inhabiting different environments. J Exp Biol 1996; 199:1295-309. [PMID: 9319167 DOI: 10.1242/jeb.199.6.1295] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The objective of this study was to determine whether differences in exercise physiology between Atlantic cod (Gadus morhua) populations from different salinity environments could be changed by acclimating individuals of each population to the natural salinity of the comparison population. The exercise-associated blood chemistry of cod from the brackish Bras d'Or lakes, which had previously been shown to be quite different from that of 'open-ocean' cod, changed to resemble the blood chemistry of their oceanic relatives after only 2 months of acclimation to full-strength salinity. In contrast, the blood chemistry of cod from the Scotian Shelf of the Northwest Atlantic Ocean showed little change after 2 months of acclimation to brackish water. These results demonstrate that the degree of osmoconformity to changes in environmental salinity is a population-specific not a species-specific trait. The blood chemistry differences between populations and salinities did not translate into differences in exercise performance: i.e. critical swimming speeds were statistically uniform across all combinations of population and salinity, although performance was more varied in fish swimming in 'non-native' waters. Other 'whole-animal' physiological characteristics, such as metabolic rate and the aerobic cost of transport, were dependent upon both population origin and the environmental salinity. Vigorous swimming was more energetically expensive at full-strength salinity than at 20 salinity, yet estimates of standard (i.e. resting) metabolic rate were lower for full-strength salinity. Environmental salinity also influenced the relative appearance of lactate and metabolic acid in the extracellular fluid compartment, with full-strength salinity favouring the relative appearance of lactate in the blood. Multivariate statistical analyses of this data set showed that, in contrast to other fish species and studies, differences in blood oxygen transport appear to account for some of the swimming performance differences seen in Atlantic cod at 2 °C. The two experimental populations were cleanly separated by a principal components analysis, regardless of the salinity to which they were acclimated, confirming our earlier contention that these cod populations are physiologically distinct. A key feature of that distinctness is the greater phenotypic plasticity exhibited by the population from the more euryhaline, more eurythermal environment.
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