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Biomedical subjects

P Robinson

Publications and source records attributed to P Robinson.

At least 37 records · Page 2Linked to original sources
PubMed2002

Reversible sensorineural hearing loss.

We present an unusual case of temporary sensorineural hearing loss in a 6-year-old child due to carbon monoxide. This was shown on both the audiograms and confirmed with objective testing using otoacoustic emissions. Carbon monoxide poisoning is one of the few recognised causes of reversible sensorineural hearing loss, though it may also lead to a permanent deficit. This is discussed along with other potential causes of reversible sensorineural hearing loss.

Audiometry, Pure-Tone↗
PubMed2002

Consensus guidelines on quantifying HIV-related oral mucosal disease.

The workshop agreed that the development of consensus quantification protocols was desirable, but that this whole field was underdeveloped, to date. The working goals were therefore redefined (vide infra). Three possible protocols were presented and discussed relating to oral hairy leukoplakia, oral ulceration (NOS) and oral candidiasis. There was agreement that different data-set protocols would have to be developed for specific HIV-related mucosal diseases. Furthermore, the data set should be consistent, standardized and disaggregated. In this way, with everyone working to the same standards of outcome, data from geographically, nationally, socially or culturally different areas could be readily compared. A future meeting to generate the disease-specific protocols would, most likely, be needed.

AIDS-Related Opportunistic Infections↗
PubMed2002

Evaluation of Bioglass/dextran composite as a bone graft substitute.

Allogenic and alloplastic bone graft substitutes serve either as bioinert or bioactive osteoconductors. Bioglass is a bioactive osteoconductor and also shows osteoproductive effects due to its high level of bioactivity. However, the material lacks some cohesiveness when used in augmenting certain bony surfaces, i.e. large or pleomorphic defects. The addition of medium molecular weight dextran modifies the particulate to a putty consistency and improves the handling characteristics. The objective of this study is to evaluate the influence of dextran upon the bioactive properties of Bioglass. Standardized bony defects in the lateral femoral condyles in adult New Zealand white rabbits were filled with one of five material groups: (1) autogenous bone; (2) Bioglass particulate; (3) Bioglass particulate mixed with dextran to a putty-like consistency; (4) a mixture of Bioglass and autogenous bone; (5) a mixture of Bioglass putty with autogenous bone. Postoperative healing was observed after periods of 2 days, 1, 2, 3, 6 and 12 weeks. Results showed no evidence of toxicity in the dextran-containing materials, and defects in all test groups showed 100% bony ingrowth within 6 weeks. The addition of medium molecular weight dextran did not appear to alter the bioactive properties of Bioglass and had no adverse influence upon the ingrowth of bone into the defect sites.

Animals↗
PubMed2002

Anteromedial impingement of the ankle: using MR arthrography to assess the anteromedial recess.

OBJECTIVE: Our objective was to describe the appearance of the anteromedial tibiotalar joint on MR arthrography in patients with clinically and arthroscopically confirmed anteromedial impingement. CONCLUSION: Anteromedial impingement of the ankle is now being recognized in the orthopedic literature as a distinct entity. MR arthrographic findings of anteromedial impingement include capsular and synovial soft-tissue thickening anterior to the tibiotalar ligaments and any associated osseous abnormality. Although anteromedial impingement is uncommon compared with other impingement syndromes of the ankle, the radiologist should be aware of the diagnosis and possible findings on cross-sectional imaging.

Adolescent↗
PubMed2001

Expression of IL-15 and IL-4 in IFN-gamma-independent control of experimental human Cryptosporidium parvum infection.

We have previously demonstrated interferon gamma (IFN-gamma) in intestinal mucosa after experimental human Cryptosporidium parvum infection, but expression was limited to sensitized volunteers. To characterize IFN-gamma-independent mechanisms in control of infection, jejunal biopsies from immunocompetent volunteers experimentally challenged with C. parvum were examined by in situ hybridization for interleukin (IL-)15 and IL-4 mRNA with confirmation by immunohistochemistry. Cytokine expression was correlated with prechallenge anti- C. parvum IgG, symptoms, oocyst shedding, and prior IFN-gamma expression data. IL-15 expression was noted only in those without prior sensitization, who did not express IFN-gamma. By contrast, expression of IL-4 was associated with prior sensitization. IL-15 was only detected in those with symptoms (6/14 symptomatic vs 0/3 asymptomatic, P<0.05). Among 14 volunteers who did not express IFN-gamma, oocyst shedding was lower in those expressing IL-15. Overall, 14/15 volunteers who did not shed oocysts expressed either IFN-gamma or IL-15. There was no correlation between expression of IL-4 and symptoms or oocyst shedding. In conclusion, IL-15 expression was associated with control of oocyst shedding in those not expressing IFN-gamma. These data suggest that IL-15 is involved in IFN-gamma independent mechanisms of control of human cryptosporidiosis, perhaps via activation of the innate immune response.

Adolescent↗
PubMed2001

Development of drug resistance in patients receiving combinations of zidovudine, didanosine and nevirapine.

OBJECTIVE: To evaluate the development of phenotypic and genotypic resistance to zidovudine, didanosine and nevirapine as a function of the virologic response to therapy in a group of drug-naive individuals receiving various combinations of these agents. DESIGN: All patients were enrolled in a double-blind controlled randomized trial (the INCAS study) and were selected for detailed resistance studies based on specimen availability and virologic response. METHODS: Within the three study groups (zidovudine/nevirapine, zidovudine/didanosine or zidovudine/nevirapine/didanosine), 16, 19 and 24 patients, respectively, had evaluable baseline isolates and remained in the study > 24 weeks. Phenotypic resistance to all three drugs was evaluated using the VIRCO recombinant virus assay. Genotypic sequencing was done on selected specimens from patients receiving zidovudine/nevirapine/didanosine. RESULTS: After 24 weeks, all available isolates taken from patients receiving nevirapine were resistant to this agent, while 18/21 (86%) patients receiving triple therapy carried such isolates at 30--60 weeks. At 24 weeks, zidovudine resistance developed in 4/40 isolates but was more frequent after 30--60 weeks, especially in patients on two drugs. The degree of zidovudine resistance (rise in concentration required for 50% inhibition) appeared lower in the triple therapy group compared with zidovudine/didanosine (P = 0.0004). All nevirapine-resistant isolates that were sequenced carried at least one mutation associated with resistance, most often K103N and/or Y181C. CONCLUSION: The use of highly active drug therapies may be associated with a beneficial effect on the development of antiretroviral drug resistance. The characteristics of virologic suppression that must be maintained to avoid resistance are currently being studied in hypothesis-driven clinical trials.

Anti-HIV Agents↗
PubMed2001

Structure of the mouse Stat 3/5 locus: evolution from Drosophila to zebrafish to mouse.

Signal transducers and activators of transcription (Stat) are transcription factors that can be activated by many cytokines. While Drosophila contains only one Stat (d-Stat), mammals contain seven, with STATs 3, 5a, and 5b being the closest functional relatives. To understand the evolutionary relationship between d-Stat and vertebrate STATs 3 and 5, we isolated, sequenced, and analyzed the zebrafish Stat3 (z-Stat3) gene and a 500-kb region spanning mouse chromosome 11, 60.5 cM containing three Stat genes (m-Stats). Within this region we identified the genes encoding m-Stats 3, 5a, and 5b, Cnp1, Hcrt/Orexin, Ptrf, GCN5, mDj11, and four new genes. The 5' ends of the m-Stat5a and m-Stat5b genes are juxtaposed to each other, and the 3' ends of the m-Stat3 and Stat5a genes face each other. While the m-Stat5a and m-Stat3 genes have one promoter each, which are active in many tissues, the m-Stat5b gene acquired two distinct promoters. The distal promoter is expressed ubiquitously, and transcription from the proximal promoter is restricted to liver, muscle, and mammary tissue. Through a comparison of exon-intron boundaries from the m-Stat3, m-Stat5a, and m-Stat5b, z-Stat3, and d-Stat genes, we deduced their evolutionary relationship. We propose that the Stat3 and Stat5 lineages are derived from the duplication of a common primordial gene and that d-Stat is a part of the Stat5 lineage.

Animals↗
PubMed2001

Predicted maximal oxygen uptake in normal Hong Kong Chinese schoolchildren and those with respiratory diseases.

To assess the maximum oxygen uptake (V'O2 max) of Hong Kong Chinese children and to explore its association with respiratory illnesses, we conducted the Multistage Fitness Test (MFT), a 20-m shuttle run test, in 1,427 schoolchildren aged between 8-12 years. Information on respiratory symptoms in the previous year, cumulative respiratory illnesses, and habitual physical activities were collected. Spirometry was carried out to derive forced expiratory volume in 1 sec (FEV1). The V'O2max was 30.3 mL x kg( - 1) x min( - 1) for boys, and 28.6-mL x kg( - 1) x min( - 1) for girls; these values were low by Western standards. V'O2max was significantly reduced in children with asthma ( - 1.3 mL x kg( - 1) x min( - 1)) and bronchitis ( - 0.7.mL x kg( - 1) x min( - 1)) when adjusted for other covariates. A significant decrease in FEV1 was also observed in these children. The correlation between V'O2max and FEV1 was significant but weak. Habitual physical activity was an independent predictor of V'O2max, but not of FEV1. The low V'O2 max in Hong Kong children may be explained in part by ethnic differences and possibly a low level of physical activity.

Child↗
PubMed2001

Manuscript evolution.

Frequently, letters, words and sentences are used in undergraduate textbooks and the popular press as an analogy for the coding, transfer and corruption of information in DNA. We discuss here how the converse can be exploited, by using programs designed for biological analysis of sequence evolution to uncover the relationships between different manuscript versions of a text. We point out similarities between the evolution of DNA and the evolution of texts.

Evolution, Molecular↗
PubMed2001

Manuscript evolution.

Frequently, letters, words and sentences are used in undergraduate textbooks and the popular press as an analogy for the coding, transfer and corruption of information in DNA. We discuss here how the converse can be exploited, by using programs designed for biological analysis of sequence evolution to uncover the relationships between different manuscript versions of a text. We point out similarities between the evolution of DNA and the evolution of texts.

DNA↗
PubMed2001

Risk-factors for meningococcal disease in Victoria, Australia, in 1997.

In Victoria between 1990 and 1996, meningococcal infections occurred in 1-2/100,000 people each year, with sometimes devastating outcome. In 1997, a typical year, we conducted a case-control study of all cases notified to the State Disease Control Unit, to investigate personal, environmental and lifestyle risk factors. In bivariate analysis many exposures were statistically significantly different (at P = 0.01) in cases and controls. The level of risk, and specific risks, differed between children (under 16) and adults (16 years and over). In multivariate analysis few exposures remained significant (at P = 0.05). However, these included having a smoker amongst close contacts, exposure to construction dust, recent illness, a history of snoring and speech problems, and sharing a bedroom. Besides confirming some previously identified risk factors, this is the first time that snoring and speech problems have been identified as risk factors for meningococcal disease.

Adolescent↗
PubMed2001

Laboratory enhanced surveillance for meningococcal disease in Victoria.

OBJECTIVE: To describe the epidemiological and microbiological characteristics and notification patterns of invasive meningococcal disease (IMD) in Victoria between 1990 and 1999. METHODS: Cases of IMD occurring between 1990 and 1995 identified in any of three databases were combined, matching where possible. Statistical modelling provided estimates of cases missing from all datasets. Notification sources for 1999 and 2000 cases were identified. Cases identified from notification and laboratory results provided the data to describe IMD epidemiology between 1990 and 1999. RESULTS: Between 1990 and 1995, 479 cases of IMD were identified. Three individual datasets each identified between 62 and 82% of cases and 47% of cases were identified in all three datasets. Statistical modelling estimated that between 37 and 83 additional cases were not identified by any dataset. Serogroup B and C strains caused 63 and 33% of culture-positive cases, respectively, with a substantial rise in serogroup C cases in 1999. Epidemiological characteristics remained relatively constant between 1990 and 1998, but an increase in patient age was seen in cases with serogroup C disease in 1999. In addition to three clonal strains seen elsewhere, an additional strain was identified that was unique to Victoria. Since January 1999, only 72% of notifications have come from treating doctors. CONCLUSIONS: Meningococcal disease is of increasing public health significance in Victoria. Laboratory enhanced notification has improved case identification and detailed microbiological information has improved our understanding of the changing epidemiology of this disease. Collaboration with laboratories and other agencies, active investigation of putative cases and microbiological monitoring are important elements in supporting public health decisions about the control of IMD.

Age Distribution↗