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Biomedical subjects

C Lloyd

Publications and source records attributed to C Lloyd.

At least 19 recordsLinked to original sources

The DNA sequence and biological annotation of human chromosome 1.

The reference sequence for each human chromosome provides the framework for understanding genome function, variation and evolution. Here we report the finished sequence and biological annotation of human chromosome 1. Chromosome 1 is gene-dense, with 3,141 genes and 991 pseudogenes, and many coding sequences overlap. Rearrangements and mutations of chromosome 1 are prevalent in cancer and many other diseases. Patterns of sequence variation reveal signals of recent selection in specific genes that may contribute to human fitness, and also in regions where no function is evident. Fine-scale recombination occurs in hotspots of varying intensity along the sequence, and is enriched near genes. These and other studies of human biology and disease encoded within chromosome 1 are made possible with the highly accurate annotated sequence, as part of the completed set of chromosome sequences that comprise the reference human genome.

Base Sequence↗

The DNA sequence and comparative analysis of human chromosome 10.

The finished sequence of human chromosome 10 comprises a total of 131,666,441 base pairs. It represents 99.4% of the euchromatic DNA and includes one megabase of heterochromatic sequence within the pericentromeric region of the short and long arm of the chromosome. Sequence annotation revealed 1,357 genes, of which 816 are protein coding, and 430 are pseudogenes. We observed widespread occurrence of overlapping coding genes (either strand) and identified 67 antisense transcripts. Our analysis suggests that both inter- and intrachromosomal segmental duplications have impacted on the gene count on chromosome 10. Multispecies comparative analysis indicated that we can readily annotate the protein-coding genes with current resources. We estimate that over 95% of all coding exons were identified in this study. Assessment of single base changes between the human chromosome 10 and chimpanzee sequence revealed nonsense mutations in only 21 coding genes with respect to the human sequence.

Animals↗

DNA sequence and analysis of human chromosome 9.

Chromosome 9 is highly structurally polymorphic. It contains the largest autosomal block of heterochromatin, which is heteromorphic in 6-8% of humans, whereas pericentric inversions occur in more than 1% of the population. The finished euchromatic sequence of chromosome 9 comprises 109,044,351 base pairs and represents >99.6% of the region. Analysis of the sequence reveals many intra- and interchromosomal duplications, including segmental duplications adjacent to both the centromere and the large heterochromatic block. We have annotated 1,149 genes, including genes implicated in male-to-female sex reversal, cancer and neurodegenerative disease, and 426 pseudogenes. The chromosome contains the largest interferon gene cluster in the human genome. There is also a region of exceptionally high gene and G + C content including genes paralogous to those in the major histocompatibility complex. We have also detected recently duplicated genes that exhibit different rates of sequence divergence, presumably reflecting natural selection.

Base Composition↗

The DNA sequence and analysis of human chromosome 13.

Chromosome 13 is the largest acrocentric human chromosome. It carries genes involved in cancer including the breast cancer type 2 (BRCA2) and retinoblastoma (RB1) genes, is frequently rearranged in B-cell chronic lymphocytic leukaemia, and contains the DAOA locus associated with bipolar disorder and schizophrenia. We describe completion and analysis of 95.5 megabases (Mb) of sequence from chromosome 13, which contains 633 genes and 296 pseudogenes. We estimate that more than 95.4% of the protein-coding genes of this chromosome have been identified, on the basis of comparison with other vertebrate genome sequences. Additionally, 105 putative non-coding RNA genes were found. Chromosome 13 has one of the lowest gene densities (6.5 genes per Mb) among human chromosomes, and contains a central region of 38 Mb where the gene density drops to only 3.1 genes per Mb.

Chromosome Mapping↗

Strategy for hepatoblastoma management: Transplant versus nontransplant surgery.

BACKGROUND: Liver transplantation now is proposed for managing selected hepatoblastoma cases. Indications are not yet well defined. METHODS: The case records of 34 children with hepatoblastoma treated over a period of 10 years (1991 to 2000) were reviewed retrospectively. RESULTS: All patients benefited from preoperative chemotherapy. Twenty patients underwent major hepatic resections. Twelve patients, in absence of residual metastasis, underwent liver transplant because the tumour remained unresectable after chemotherapy. Two patients who presented with recurrence after a right hepatectomy, benefited from transplant as a second option. Two other patients did not undergo surgery because of widespread disease or resistance to chemotherapy. Disease-free survival rates were 95% after surgical resection, 100% when primary transplant was performed in patients with good response to chemotherapy, 60% after transplantation in patients with poor response to chemotherapy, 50% in patients with transplant as second option, and 0% in patients not undergoing surgery. CONCLUSIONS: Transplantation is a potentially curative option for unresectable hepatoblastoma when chemosensitive (decrease in alpha-fetoprotein and decrease in tumour size). In this context, also favourable cases with good response but difficult resections with doubtful margins of resection may best be proposed for primary transplantation. Patients with recurrent or resistant disease are not good candidates.

Antineoplastic Agents↗

P34(cdc2) kinase is associated with cortical microtubules from higher plant protoplasts.

The cell cycle regulatory enzyme p34(cdc2) kinase is known to be localized to the preprophase band, the spindle and the phragmoplast, but not to interphase cortical microtubules. This was investigated further by mechanically cleaving substrate-attached protoplasts to leave plasma membrane disks bearing microtubules freed of nuclear and cytosolic signal. Antibodies to PSTAIRE and to specific C-terminal peptides of cdc2a, were used in immunofluorescence, protein blotting and immunogold electron microscopy to demonstrate that antigen is located on the cortical microtubules of carrot, tobacco BY-2 and Arabidopsis cells.

Animals↗

Initial sequencing and analysis of the human genome.

The human genome holds an extraordinary trove of information about human development, physiology, medicine and evolution. Here we report the results of an international collaboration to produce and make freely available a draft sequence of the human genome. We also present an initial analysis of the data, describing some of the insights that can be gleaned from the sequence.

Animals↗

Sequence, structure and pathology of the fully annotated terminal 2 Mb of the short arm of human chromosome 16.

We have sequenced 1949 kb from the terminal Giemsa light band of human chromosome 16p, enabling us to fully annotate the region extending from the telomeric repeats to the previously published tuberous sclerosis disease 2 (TSC2) and polycystic kidney disease 1 (PKD1) genes. This region can be subdivided into two GC-rich, Alu-rich domains and one GC-rich, Alu-poor domain. The entire region is extremely gene rich, containing 100 confirmed genes and 20 predicted genes. Many of the genes encode widely expressed proteins orchestrating basic cellular processes (e.g. DNA recombination, repair, transcription, RNA processing, signal transduction, intracellular signalling and mRNA translation). Others, such as the alpha globin genes (HBA1 and HBA2), PDIP and BAIAP3, are specialized tissue-restricted genes. Some of the genes have been previously implicated in the pathophysiology of important human genetic diseases (e.g. asthma, cataracts and the ATR-16 syndrome). Others are known disease genes for alpha thalassaemia, adult polycystic kidney disease and tuberous sclerosis. There is also linkage evidence for bipolar affective disorder, epilepsy and autism in this region. Sixty-three chromosomal deletions reported here and elsewhere allow us to interpret the results of removing progressively larger numbers of genes from this well defined human telomeric region.

Adolescent↗

Dexamethasone increases the expression of membrane macrophage colony stimulating factor from retrovirally transduced tumor cells expressing macrophage colony stimulating factor.

Many different tumor cell types (breast, ovarian, glioma, liver and colon) were retrovirally transduced with the human macrophage colony stimulating factor (M-CSF) gene (either the membrane associated form [mM-CSF] or the secreted form [sM-CSF]). These cells were tested for their ability to display increased amounts of mM-CSF in response to dexamethasone. M-CSF-transfected tumor cells expressed additional mM-CSF in response to 18-72 h incubations with 3-15 microg/ml dexamethasone, while non-transfected parental cells were unaffected by this treatment. Increased mM-CSF protein expression on the M-CSF transduced cells was observed by flow cytometry and Western blotting using M-CSF specific antibodies. Northern blot analysis revealed an increase in the mM-CSF specific transcripts within the dexamethasone-treated mM-CSF transduced cells, but this was not seen within the non-transfected tumor cells that were treated with dexamethasone. ICAM-1 expression was unaffected by dexamethasone treatment, indicating that this response is mM-CSF specific. All trans-retinal and 1,25-dihydroxy vitamin D3 compounds that have been reported to induce M-CSF expression failed to increase mM-CSF. When dexamethasone-treated mM-CSF transfected clones were used as target cells for macrophage-mediated cytotoxicity assays, an increased killing with the dexamethasone-treated cells was seen. The macrophage-mediated cytotoxicity of these mM-CSF expressing tumor cells was blocked with excess recombinant M-CSF by saturating M-CSF receptors on the macrophage that is required for this form of tumor cell killing. This work suggests the possibility that dexamethasone may prove useful for vaccination purposes using mM-CSF retrovirally transfected tumor cells.

Animals↗

The leisure satisfaction of people with psychiatric disabilities.

Leisure is considered to be an important part of life for every individual. This is even more so for people who have limited employment prospects and life options. The primary handicaps associated with mental illness create problems with social relationships and can hinder individuals from participating in or enjoying leisure pursuits. The aim of this exploratory study was to examine leisure satisfaction in a sample of one hundred adults with a mental illness who were clients of an Australian community mental health rehabilitation service. The Leisure Satisfaction Survey and the Life Skills Profile were administered to these clients to determine their leisure satisfaction and general functioning. Contrary to expectations, results indicated that the clients of mental health rehabilitation services believe that their leisure pursuits provide them with intellectual stimulation, enjoyable relationships with others and relaxation, suggesting that they are very satisfied with the activities they engage in during their leisure time. In general, these clients were more satisfied with their leisure than the normative population. Consistent with expectations, clients with lower disability and in particular with high capacity for social contact were most satisfied with their leisure pursuits. The significance of these results and the utility of the Leisure Satisfaction Survey with this population are discussed.

Adult↗

Microtubule-associated proteins in plants--why we need a MAP.

Plants have four main microtubule assemblies. Three are involved in arranging when and where the cell wall is laid down and have no direct homologues in animals. Microtubule-associated proteins are important components of these assemblies, and we are now starting to uncover what these proteins are and how they might work.

Animals↗

Practice-based research: the Oregon experience.

BACKGROUND: Practice-based research links community-based physicians and their patients with investigators at academic institutions. In 1992, Western States Chiropractic College developed an infrastructure, the Center for Outcomes Studies, to support practice-based research. The Low Back Pain Study, undertaken in collaboration with Oregon Health Sciences University, 111 medical physicians, and 60 chiropractors, relied on the Center for Outcomes Studies infrastructure for support in project implementation and maintenance. RESULTS: Challenges, many of them critical, were a regular occurrence: dealing with unforeseen obstacles, establishing and maintaining physician buy-in, establishing and maintaining staff buy-in, implementing the protocol as directed and with minimal intrusiveness, maintaining enthusiasm for the project over time, and knowing where (and where not) to allocate the Study's time, energy, and money. Strategies were developed to overcome or minimize the impact of problems on a case-by-case basis. CONCLUSIONS: Successful practice-based research requires an awareness of study design issues and an appreciation of clinical practice logistics and priorities. Every effort must be made to include doctors and office staff in the implementation of the study in a manner that minimizes the study's intrusiveness and its economic impact on office organization, routine, and personnel. Investigators must understand and accept that there will be areas of the research environment over which they have no direct control. The challenges will be many, but they will be diminished by the rewards.

Algorithms↗

Vasospasm-induced heart block.

A syncopal episode in an elderly patient with a history of carotid disease, multiple cardiac risk factors, and new onset chest pain presents diagnostic challenges. This case study describes the experience of a woman with coronary vasospasm accompanied by conduction deficits. The patient's history, diagnostic work-up, and treatment program are presented. The relationship between the coronary artery anatomic defects and the conduction abnormalities are discussed.

Aged↗