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Fielding S, Kerr S, Godber C. Lithium in the over-65s--a dedicated monitoring service leads to a better quality of treatment supervision. Int J Geriatr Psychiatry 1999; 14:985-7. [PMID: 10556872] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/14/2023]
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152
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Humar A, Kerr S, Gillingham KJ, Matas AJ. Features of acute rejection that increase risk for chronic rejection. Transplantation 1999; 68:1200-3. [PMID: 10551652 DOI: 10.1097/00007890-199910270-00023] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND Acute rejection (AR) has been shown to be a significant risk factor for chronic rejection (CR) in kidney transplant recipients, yet many recipients with AR do not progress to CR. The purpose of this study was to determine if certain AR episodes are associated with a worse prognosis. METHODS The study group consisted of 279 kidney transplant recipients, all treated for a single episode of biopsy-proven AR. All AR episodes were initially treated with steroids; steroid-resistant rejection was managed with an antibody preparation. RESULTS First, by univariate techniques, we determined the clinical impact of severity of AR (as estimated by delta creatinine [dCr], defined as the change in baseline serum creatinine level 6 weeks after AR treatment) on two different endpoints--biopsy-proven CR and graft survival. Irrespective of 6-week dCr, all recipients with AR had a significantly increased risk of CR vs. those with no AR (P<0.01). Recipients with dCr between 0.5 and 1.0 mg/dl had a significantly higher incidence of CR vs. those with dCr <0.5 mg/dl (P<0.05), but a significantly lower incidence vs. those with dCr >1.0 mg/dl (P<0.05). We then performed multivariate analysis. We used severity of AR in addition to other variables (e.g., timing of AR, donor age) to determine which factors were most associated with risk for CR and graft loss. Risk for CR increased with AR episodes occurring >6 months after transplant (relative risk [RR] = 3.8, P = 0.005); with moderate or severe (vs. mild) AR episodes (RR = 2.7, P = 0.05); and with dCr >0.5 mg(dl (vs. <0.5 mg/dl) at 6 weeks after AR treatment (RR = 2.3, P = 0.1). Findings were similar when graft survival (death-censored) was the endpoint instead of CR. CONCLUSIONS All AR episodes are associated with some increase in the risk for CR. But AR episodes occurring >6 months after transplant and those of increased severity (as assessed qualitatively by histologic grading and quantitatively by dCr) confer the greatest risk. Recipients with these risk factors could be targeted with measures to decrease their risk for CR, including trials of novel immunosuppressive regimens.
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Kerr S, Brosnan MJ, McIntyre M, Reid JL, Dominiczak AF, Hamilton CA. Superoxide anion production is increased in a model of genetic hypertension: role of the endothelium. Hypertension 1999; 33:1353-8. [PMID: 10373215 DOI: 10.1161/01.hyp.33.6.1353] [Citation(s) in RCA: 282] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The hypothesis that the decreased nitric oxide (NO) availability observed in spontaneously hypertensive stroke-prone rats (SHRSP) is due to excess superoxide (O2-) was examined. O2- generation, measured by lucigenin chemiluminescence, was studied in 12- to 16-week male and female Wistar-Kyoto rats (WKY) and SHRSP. In addition, expression of the gene encoding endothelial NO synthase, the enzyme involved in NO generation, was investigated. O2- generation was increased in male and female SHRSP (4.11+/-0.24 and 3. 84+/-0.28 nmol O2-. min-1. mg-1 respectively) compared with their WKY counterparts and was significantly higher in male than female WKY (1.22+/-0.08 in males and 0.8+/-0.08 nmol O2-. min-1. mg-1 respectively) (SHRSP versus WKY P<0.0001, 95% CI -3.39, -2.51; male versus female WKY P=0.0029, 95% CI -0.67, -0.17). Removal of the endothelium by rubbing or addition of NO synthase inhibitors attenuated O2- generation in SHRSP but not WKY. In males, removal of the endothelium reduced O2- generation from 3.86+/-0.12 to 1.35+/-0. 08 nmol. min-1. mg-1 (P<0.0001, 95% CI 2.29, 2.81), whereas addition of L-NAME caused a reduction from 4.13+/-0.17 to 1.32+/-0.16 nmol. min-1. mg-1 (P<0.0001, 95% CI 2.36, 2.83). Similar reductions were observed in females. L-arginine had no significant effect, but tetrahydrobiopterin significantly decreased O2- generation in SHRSP from 4.04+/-0.11 to 2.36+/-0.40 nmol. min-1. mg-1 (P=0.0026, 95% CI 0.89, 2.44). Endothelial NO synthase mRNA expression was significantly greater in SHRSP than in WKY and in WKY males than in WKY females. These results show that O2- generation is increased in SHRSP and that the tissue and enzymatic sources of this excess O2- appear to be the endothelium and eNOS, respectively. The increase in O2- generation could explain the decreased availability of basal NO observed in this model of genetic hypertension.
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MESH Headings
- Animals
- Aorta, Abdominal/metabolism
- Aorta, Thoracic/enzymology
- Blood Pressure
- Endothelium, Vascular/physiology
- Endothelium, Vascular/physiopathology
- Female
- Hypertension/genetics
- Hypertension/metabolism
- Hypertension/physiopathology
- In Vitro Techniques
- Male
- Muscle, Smooth, Vascular/metabolism
- Nitric Oxide Synthase/genetics
- Nitric Oxide Synthase Type III
- RNA, Messenger/genetics
- Rats
- Rats, Inbred SHR
- Rats, Inbred WKY
- Sex Characteristics
- Species Specificity
- Superoxides/metabolism
- Transcription, Genetic
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Kerr S, Marshall C, Sinclair D. Emergency physicians versus laboratory technicians: are the urinalysis and microscopy results comparable? A pilot study. J Emerg Med 1999; 17:399-404. [PMID: 10338228 DOI: 10.1016/s0736-4679(99)00016-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In the literature to date, there are no studies that directly evaluate microscopic urine examination results obtained by a physician compared to those of a trained laboratory technician. Our purpose in undertaking this study was to determine whether there would be comparable results obtained by these two groups. The study took place in an Emergency Medicine Department with 45,000 visits annually. Each urine sample obtained on patients presenting to the Emergency Department was divided into two lots: one was sent to the laboratory and the other was analyzed by the emergency physician. A comparison of both dipstick and microscopic results by physician and laboratory staff was then made using sensitivity, specificity, and Kappa analysis. Statistical analysis of the data revealed close agreement between the emergency physician and laboratory technician with respect to the following components of urinalysis: red blood cell urinalysis and microscopy, leukocyte esterase, and nitrite testing. Microscopy for white cells and bacteria and testing for proteinuria were not in close agreement. Urinalysis by emergency physicians is comparable to laboratory technicians for a number of the testing components. However, in this limited pilot study, emergency physicians were not able to consistently perform urinalysis for the laboratory standard.
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155
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Humar A, Arrazola L, Kerr S, Gillingham K, Matas A. CADAVER DONORS GREATER THAN AGE 55: WHICH KIDNEYS TO USE? Transplantation 1999. [DOI: 10.1097/00007890-199904150-00359] [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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156
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Kerr S, O'Keeffe G, Kilty C, Doyle S. Undenatured parvovirus B19 antigens are essential for the accurate detection of parvovirus B19 IgG. J Med Virol 1999; 57:179-85. [PMID: 9892405 DOI: 10.1002/(sici)1096-9071(199902)57:2<179::aid-jmv16>3.0.co;2-t] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Recombinant versions of parvovirus B19 capsid proteins VP1 and VP2 are used for immunodiagnostic assays for detection of antiviral antibodies. The immune response to B19 is characterized by a gradual loss of antibodies directed against linear epitopes of VP2. A similar occurrence for antibodies raised against VP1 protein would represent a limitation to serological assays incorporating denatured versions of either viral antigen. Four detection systems for B19 Ig detection have been developed, including an IgG enzyme immunoassay (EIA) based on undenatured VP2, an immunofluorescence assay (IFA) based on undenatured VP1, a Western blot assay incorporating denatured VP1 and VP2, and an alternative blot system using denatured VP1 but undenatured VP2. Specimens (n=108) were tested by all four systems and identical results were obtained by EIA, IFA, and alternative blot systems, whereby 75/108 (69%) were B19 IgG-positive. Twelve B19 IgG-positive specimens, representing 16% (12/75) of the confirmed positives, did not react to either viral antigens when tested by Western blot. It is concluded that these sera do not react with linear epitopes of VP1 and VP2 antigens. Eighty-five different specimens, which had previously been shown to be both B19 IgM- and IgG-positive by EIA and IFA, were positive by B19 IgM and IgG Western blot. In the IgG Western blot assay, 69 reacted with both VP1 and VP2 and 16 with VP1 only. It is concluded that there is a requirement for at least one undenatured antigen for the immunological detection of B19 IgG.
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157
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Humar A, Kerr S, Hassoun A, Granger D, Suhr B, Matas A. The association between acute rejection and chronic rejection in kidney transplantation. Transplant Proc 1999; 31:1302-3. [PMID: 10083581 DOI: 10.1016/s0041-1345(98)02006-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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158
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Jones CA, Leese GP, Kerr S, Bestwick K, Isherwood DI, Vora JP, Hughes DA, Smith C. Development and progression of microalbuminuria in a clinic sample of patients with insulin dependent diabetes mellitus. Arch Dis Child 1998; 78:518-23. [PMID: 9713006 PMCID: PMC1717597 DOI: 10.1136/adc.78.6.518] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The evolution of abnormal albumin excretion and its association with suggested risk factors were studied in 233 children with insulin dependent diabetes mellitus (IDDM) attending a single paediatric diabetic clinic over an eight year period. Yearly albumin:creatinine ratios (ACR; measured in mg/mmol) in early morning urine samples, glycated haemoglobin (HbA1c), and blood pressure were recorded. Thirty four (14.5%) children had a persistently raised ACR (ACR > or = 2.5 mg/mmol on at least three consecutive occasions) and 21 (9%) had an intermittently raised ACR (ACR > or = 2.5 mg/mmol on at least two occasions). Factors associated with a persistently raised ACR compared with normal albuminuria in IDDM included longer duration of diabetes, raised median HbA1c during the first five years after diagnosis, and final age adjusted systolic and diastolic blood pressure represented as standard deviation scores. The onset of persistently raised ACR in 13 of 34 children was before puberty and in 23 of 34 children it was within the first four years of diagnosis. The cross sectional prevalence of raised ACR was 12.9% at one year, 18.3% at five years, and 33% at 10 years after diagnosis. Raised ACR occurs frequently before puberty and in the early stages of childhood diabetes.
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159
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Peters M, Kerr S. Recombinant tissue plasminogen activator restores perfusion in meningococcal purpura fulminans. Crit Care Med 1998; 26:972-3. [PMID: 9590332 DOI: 10.1097/00003246-199805000-00041] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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160
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Kerr S. Planning for success. EDTNA/ERCA JOURNAL (ENGLISH ED.) 1998; 24:49-51. [PMID: 10392067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/13/2023]
Abstract
Being a nurse today and striving for 100% job satisfaction while ensuring a patient's well-being is not an easy task in the current changing and challenging environment. However, careful planning might be the key to success. This article focuses on 'How to Plan' and gives some practical tips for nurses in their daily work. The article then offers three case stories of renal units that have developed objectives and a plan to achieve a successful dialysis programme.
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161
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Kerr S. Dental management of the patient with ESRD. PROBE (OTTAWA, ONT.) 1998; 26:160-2. [PMID: 9518785] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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162
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163
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Kerr S, Johnson E, Pandian K, Gillingham K, Matas A. Psychological impact of a failed kidney transplant. Transplant Proc 1997. [PMID: 9123430 DOI: 10.1016/s0041-1345(96)00680] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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164
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Kerr S. Clinical aspects of schizophrenia. Nurs Stand 1997; 11:50-3; quiz 55-6. [PMID: 9165902 DOI: 10.7748/ns.11.30.50.s46] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
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165
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Kerr S, Johnson E, Pandian K, Gillingham K, Matas A. Psychological impact of a failed kidney transplant. Transplant Proc 1997; 29:1573. [PMID: 9123430 DOI: 10.1016/s0041-1345(96)00680-x] [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: 02/04/2023]
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166
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Prosser J, Inglis JD, Condie A, Ma K, Kerr S, Thakrar R, Taylor K, Cameron JM, Cooke HJ. Degeneracy in human multicopy RBM (YRRM), a candidate spermatogenesis gene. Mamm Genome 1996; 7:835-42. [PMID: 8875892 DOI: 10.1007/s003359900246] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
In order to search for mutations in the multicopy RBM genes that might be associated with male infertility, we have used sequence data from the reported cDNA clone to determine the intron exon boundaries of the YRRM 1 gene. This gene has 12 exons, three of which encode the putative RNA binding domain of the protein. Different copies of the gene contain sequence variations and, additionally, give rise to transcripts with different numbers of copies of the repeated SRGY motif. Since mutations in the RNA binding domain would seem likely to have an effect on the activity of the protein, we have scanned these exons for mutations by SSCP on DNA from normal and infertile men. Sequence differences in the exon encoding the N-terminal part of the RNA binding domain account for at least four different classes of the gene and give rise to different SSCP conformers. Sequence analysis shows that one of these classes is a pseudogene and that the members of another class are nonfunctional. RT-PCR shows that all classes are transcribed and that the A class is most abundant. We have found a point mutation that alters the highly conserved RNP2 motif in one infertile patient. This mutation is also found in his father. We have used PCR followed by SSCP analysis to map RBM on a Y Chromosome (Chr) YAC contig and have demonstrated a distribution that spans a major part of this chromosome's euchromatin.
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Abstract
The population pharmacokinetics of caffeine were investigated in 60 neonates and young infants using data collected during routine therapeutic drug monitoring. Clearance was influenced by body weight and postnatal age, and increased in the presence of dexamethasone. No clinical factors were identified that influenced volume of distribution. The population pharmacokinetic parameter estimates were then tested prospectively in a further 20 neonates. Although they produced unbiased results, the dexamethasone effect could not be identified. A final analysis using all 80 patients found clearance (L/day) = 0.14 x weight (kg) + 0.0024 x postnatal age (days) (+/- 20%) and volume of distribution = 0.82 L (+/- 24%). Simulations based on these results indicated that the current dosage guidelines of 20 mg/kg loading dose of caffeine citrate followed by a 5 mg/kg/day maintenance dose should achieve concentrations within the traditional target range in > 70% of neonates.
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168
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Cooke HJ, Lee M, Kerr S, Ruggiu M. A murine homologue of the human DAZ gene is autosomal and expressed only in male and female gonads. Hum Mol Genet 1996; 5:513-6. [PMID: 8845845 DOI: 10.1093/hmg/5.4.513] [Citation(s) in RCA: 141] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
We have isolated a homologue of the human Y linked DAZ (deleted in azoospermia) gene from mouse. This gene, Dazla (Daz like, autosomal), is autosomal, located on chromosome 17 and apparently single copy. The predicted protein is highly homologous to that encoded by the DAZ gene in the N-terminal regions of the two proteins and this homology is not confined to the RNA binding domain. Analysis of its expression pattern by reverse transcription PCR shows that the transcript is only detectable in male and female gonads and that testes lacking germ cells do not contain detectable amounts of transcript. We have been unable to detect a Y-linked DAZ homologue in mouse and our results point to the possibility of a role for autosomal RNA binding proteins in mammalian gametogenesis.
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169
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Adams E, Kane N, Boyd S, Kerr S. Somatosensory evoked potentials: predictors of outcome in children with severe brain injury. J Pediatr 1996; 128:438-9. [PMID: 8774521 DOI: 10.1016/s0022-3476(96)70305-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
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170
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Davies MJ, Arsiwala SS, Moore HM, Kerr S, Sosnowski AW, Firmin RK. Extracorporeal membrane oxygenation for the treatment of massive pulmonary embolism. Ann Thorac Surg 1995; 60:1801-3. [PMID: 8787489 DOI: 10.1016/0003-4975(95)00622-2] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
After witnessing the death of a patient following pulmonary embolectomy, John H. Gibbon, Jr, developed the idea of a device for extracorporeal oxygenation and circulation. What followed has led to the present-day method of extracorporeal membrane oxygenation as an effective method of cardiorespiratory support. In this case of massive acute pulmonary embolism, its use in a conscious patient completes the circle from the first ideas of Gibbon.
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171
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Miyagi Y, Kerr S, Sugiyama A, Asai A, Shibuya M, Fujimoto H, Kuchino Y. Abundant expression of translation initiation factor EIF-4E in post-meiotic germ cells of the rat testis. J Transl Med 1995; 73:890-8. [PMID: 8558852] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
BACKGROUND Eukaryotic translation initiation factor EIF-4E is a key component in the regulation of translational efficiency of MRNAs and its increased expression may accelerate cell growth and division. EIF-4E has the potential to transform rat embryo fibroblast cells by cooperation with v-Myc or adenovirus E1A. Our previous study showed that a variety of tumor cells examined exhibited elevated levels of eIF-4E gene expression. Thus it is thought that overexpression of EIF-4E can result in aberrant growth and cell transformation. EXPERIMENTAL DESIGN To characterize rat EIF-4E, a clone containing rat eIF-4E cDNA was isolated from a rat testis cDNA library by screening with a synthetic probe prepared by the reverse transcription-polymerase chain reaction (RT-PCR) method. Based on the conserved nucleotide sequences between mouse and human eIF-4E cDNA, two oligonucleotide primers for RT-PCR were synthesized chemically. The cloned cDNA was sequenced and used as a probe for analysis of the expression level of eIF-4E mRNA in normal, differentiated rat tissues by Northern blot analysis. In situ hybridization analysis with digoxigenin-labeled antisense eIF-4E RNA as a probe was carried out to identify the eIF-4E-expressing sites in rat tissues. In addition, to analyse the phosphorylation level of EIF-4E, the proteins were fractionated from rat tissues by affinity column chromatography followed by isoelectric focusing (IEF)-gel electrophoresis. RESULTS The nucleotide sequence of the eIF-4E cDNA is highly conserved in human, rat, and mouse. Extraordinarily elevated expression, more than 50-fold compared with that in the adult rat prostate, of eIF-4E was observed in testicular germ cells of rats of reproductive age, which was much greater than that in any tumor cell lines examined so far. The amount of EIF-4E fractionated from the adult rat testis was approximately 10 times higher than that from the adult rat liver. At least half of the purified testicular EIF-4E proteins were phosphorylated, a ratio similar to that in other rat tissues such as liver. In situ hybridization analysis demonstrated that elevated expression of eIF-4E mRNA was mainly observed in post-meiotic germ cells. CONCLUSIONS Full activity of EIF-4E in translation requires the phosphorylation of the protein on a specific serine residue. Thus the elevated level of EIF-4E observed in the adult rat testis should be reflected in increase of the functional activity of EIF-4E. Based on the results of in situ hybridization analysis and characterization of EIF-4E, it was concluded that abundant EIF-4E in the testis may play an important role in spermatogenesis through translational regulation of stage-specific mRNAs during germ cell development.
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172
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Jones AR, Martin MJ, Kerr S. Treatment of epiglottitis. Br J Hosp Med (Lond) 1995; 53:174; author reply 175. [PMID: 7735670] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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173
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Claireaux G, Webber D, Kerr S, Boutilier R. Physiology and behaviour of free-swimming Atlantic cod (Gadus morhua) facing fluctuating temperature conditions. J Exp Biol 1995; 198:49-60. [PMID: 9317317 DOI: 10.1242/jeb.198.1.49] [Citation(s) in RCA: 56] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Atlantic cod (Gadus morhua L.), acclimated to 5 °C, were equipped with ultrasonic transmitters which allowed the continuous monitoring of their vertical movements and heart rate. Fish were then placed in a 125 m3 tower tank in which the various thermal conditions they encounter in their natural environment were reproduced. Physiological and behavioural responses of cod were followed in parallel to the induced environmental changes. The experimental conditions studied in the tower tank were also reproduced in a swimming respirometer, where oxygen consumption and heart rate could be monitored within the activity range of a free-swimming animal. In a homogeneous water column, a rise in temperature induced marked increases in fish swimming activity, heart rate and heart beat-to-beat variability. In a thermally stratified environment, voluntary activity also increased when the thermal structure of the water column was altered, though no temperature-dependent changes in heart rate were observed. In this case, fish avoided the new temperature conditions, exhibiting distinct thermoregulatory behaviour. Stratification of the water column also prompted daily cyclic changes in fish distribution, animals tending to be in deeper and colder water layers during the day and in shallower and warmer layers at night. Respirometry experiments revealed that the thermoregulatory behaviour observed in free-ranging fish was probably driven by the energetic expedient of maintaining the physiological status quo ­ i.e. avoiding bioenergically costly reacclimation processes. Indeed, acute temperature increases or decreases of 2.5 °C led to marked differences in oxygen consumption, with metabolic rate changes of 15 and 30 %, respectively. The persistent linear relationship between heart rate and oxygen consumption allowed us to estimate, from the heart rate recorded in free-swimming fish, the entire range of metabolic responses that cod underwent voluntarily while experiencing a thermally stratified water column. The most profound metabolic effect, however, was observed with feeding, when oxygen consumption increased by as much as 80 %, resulting in an estimated 90 % reduction in their subsequent scope for activity.
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Claireaux G, Webber D, Kerr S, Boutilier R. Physiology and behaviour of free-swimming Atlantic cod (Gadus morhua) facing fluctuating salinity and oxygenation conditions. J Exp Biol 1995; 198:61-9. [PMID: 9317341 DOI: 10.1242/jeb.198.1.61] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
1. Atlantic cod (Gadus morhua L.) acclimated to a temperature of 5 °C and 30 salinity were equipped with ultrasonic transmitters which allowed continuous monitoring of their heart rate and their position in the water column. Fish were placed in a 125 m3 tower tank which permitted various environmentally relevant modifications of the salinity and oxygenation conditions. Cod physiological and behavioural responses were followed in parallel to the environmental manipulations. Some of the experimental conditions studied in the tower tank were also reproduced in a swimming respirometer where fish oxygen consumption and heart rate were monitored at various levels of activity. 2. Lowering salinity from 30 to 26 did not change resting oxygen consumption, but increased active oxygen consumption. 3. Lowering salinity from 30 to 26 increased heart rate over the whole range of swimming speeds except at maximum speed. 4. Lowering oxygen tension to 9 kPa decreased oxygen consumption over the whole range of swimming speeds and decreased resting heart rate. 5. Low salinity did not significantly affect the relationship between heart rate and oxygen consumption. 6. Low oxygen levels decreased the oxygen transported per heart beat. 7. In the tower tank, bursts of activity were associated with tachycardias. 8. In uniform conditions, fish swam more deeply during the day than at night. 9. After an exploratory period of approximately 6 h, fish chose to remain in a low-salinity upper layer of the tank. Thereafter, high salinities were avoided. Fish tended to select low salinities if a choice was provided. 10. Fish generally avoided zones of low oxygen (<9 kPa) but continued voluntarily to enter regions with values as low as 3.0 kPa for short excursions or if food was offered.
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175
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Gentleman SM, Roberts GW, Gennarelli TA, Maxwell WL, Adams JH, Kerr S, Graham DI. Axonal injury: a universal consequence of fatal closed head injury? Acta Neuropathol 1995; 89:537-43. [PMID: 7676809 DOI: 10.1007/bf00571509] [Citation(s) in RCA: 163] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
beta-Amyloid precursor protein immunostaining has recently been shown to be a reliable method for detecting the damage to axons associated with fatal head injury. In an attempt to compare the efficacy of this technique with conventional histological detection of axonal damage, we have reanalysed sections from a large well-characterised series of head-injured and control patients. The results indicate that the frequency of axonal injury has been vastly underestimated using conventional silver techniques, and that axonal injury may in fact be an almost universal consequence of fatal head injury.
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