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Biomedical subjects

R Hall

Publications and source records attributed to R Hall.

At least 19 recordsLinked to original sources

Engineering and public health at CDC.

Engineering is the application of scientific and technical knowledge to solve human problems. Using imagination, judgment, and reasoning to apply science, technology, mathematics, and practical experience, engineers develop the design, production, and operation of useful objects or processes. During the 1940s, engineers dominated the ranks of CDC scientists. In fact, the first CDC director, Assistant Surgeon General Mark Hollis, was an engineer. CDC engineers were involved in malaria control through the elimination of standing water. Eventually the CDC mission expanded to include prevention and control of dengue, typhus, and other communicable diseases. The development of chlorination, water filtration, and sewage treatment were crucial to preventing waterborne illness. Beginning in the 1950s, CDC engineers began their work to improve public health while developing the fields of environmental health, industrial hygiene, and control of air pollution. Engineering disciplines represented at CDC today include biomedical, civil, chemical, electrical, industrial, mechanical, mining, and safety engineering. Most CDC engineers are located in the National Institute for Occupational Safety and Health (NIOSH) and the Agency for Toxic Substances and Disease Registry (ATSDR). Engineering research at CDC has a broad stakeholder base. With the cooperation of industry, labor, trade associations, and other stakeholders and partners, current work includes studies of air contaminants, mining, safety, physical agents, ergonomics, and environmental hazards. Engineering solutions remain a cornerstone of the traditional "hierarchy of controls" approach to reducing public health hazards.

Centers for Disease Control and Prevention, U.S.↗

Development of ocular disease in patients with mucous membrane pemphigoid involving the oral mucosa.

AIM: To determine the rate of development of ocular disease in patients presenting with mucous membrane pemphigoid (MMP) involving their oral mucosa. METHODS: Diagnosis of oral MMP was made on the basis of clinical signs, histology, and direct and indirect immunofluorescence. Age, race, sex, age at diagnosis, progression of eye signs, duration of follow up, and time to progression of ocular disease were recorded. RESULTS: 30 patients with established oral MMP were reviewed. The mean age at diagnosis was 65.2 years (range 46-84 years) and 16/30 (53%) were male. At initial ocular review nine (30%) patients showed ocular signs of pemphigoid, of whom two had mild (IIA IIIB), four moderate (IIB IIIC), and three severe (IIC IIID) disease. The mean interval between diagnosis of oral MMP and first ophthalmic review was 19.3 months (range 0-144). Over the period of follow up two (7%) patients developed ocular disease at 19 months and 48 months, respectively, despite having had no evidence of ocular involvement at presentation. In total, 11 (37%) patients with oral disease eventually showed ocular disease with a calculated incidence rate for the development of ocular disease of 0.03 per person year over 5 years. CONCLUSIONS: MMP may affect different tissues at different stages, often separated by many years. Patients with MMP involving their oral mucosa are at significant risk of developing ocular disease and should remain under ophthalmic review.

Aged↗

Fertility outcomes in women with hypopituitarism.

BACKGROUND: Women with hypopituitarism are known to have a poor outcome once pregnancy has been achieved by ovulation induction. There are no data, however, recording the efficacy of ovulation induction and pregnancy rates in this group of subfertile women. METHODS: The outcome of fertility treatments in all 19 women with hypopituitarism attending the fertility clinics of University College London Hospitals over the past 20 years was audited. RESULTS: Ovulation was achieved in almost all women (95%) but occurred in only 60% of treatment cycles. Pregnancy was achieved in 47% of women or 11% of cycles resulting in a live birth rate of 6.7% per cycle. Seven of the 18 pregnancies (39%) miscarried. Only 42% of women treated achieved a live birth. CONCLUSION: Ovulation induction in women with hypopituitarism yields relatively low pregnancy rates in comparison to other causes of anovulation and a high miscarriage rate. Pituitary hormone deficiency beyond gonadotrophins has a major adverse effect on achieving pregnancy.

Adult↗

New approaches to package integrity testing.

An important goal for packagers is the ability to demonstrate the integrity and sterility of each pack and determine its oxygen content with the minimum of wasteful destruction. Two nondestructive inspection systems are described.

Equipment Failure Analysis↗

Packaging issues: avoiding delamination.

Manufacturers can minimise delamination occurrence by applying the appropriate packaging design and process features. The end user can minimise the impact of fibre tear and reduce subsequent delamination by careful package opening. The occasional inconvenient delamination is a small price to pay for the high level of sterility assurance that comes with the use of Tyvek.

Biocompatible Materials↗

A rapid method for illustrating features in both coding and non-coding regions of a genome.

A bitmap display of the Fourier spectra has been developed which allows convenient whole chromosome scanning for genes and other features. Use of a limited sliding window gives rapid visualization and localization of coding regions in the chromosomes, as well as non-coding features such as repetitive DNA. The method works particularly well on organisms with a skewed base composition, to provide an overview of genomic features.

Algorithms↗

The DNA sequence and analysis of human chromosome 6.

Chromosome 6 is a metacentric chromosome that constitutes about 6% of the human genome. The finished sequence comprises 166,880,988 base pairs, representing the largest chromosome sequenced so far. The entire sequence has been subjected to high-quality manual annotation, resulting in the evidence-supported identification of 1,557 genes and 633 pseudogenes. Here we report that at least 96% of the protein-coding genes have been identified, as assessed by multi-species comparative sequence analysis, and provide evidence for the presence of further, otherwise unsupported exons/genes. Among these are genes directly implicated in cancer, schizophrenia, autoimmunity and many other diseases. Chromosome 6 harbours the largest transfer RNA gene cluster in the genome; we show that this cluster co-localizes with a region of high transcriptional activity. Within the essential immune loci of the major histocompatibility complex, we find HLA-B to be the most polymorphic gene on chromosome 6 and in the human genome.

Animals↗

Comparison of 0.2% ropivacaine and 0.25% bupivacaine for axillary brachial plexus blocks in paediatric hand surgery.

BACKGROUND: The purpose of this study was to compare the use of ropivacaine 0.2% with bupivacaine 0.25% for axillary brachial plexus block in children undergoing hand surgery. METHODS: In a double-blind, randomized study, 35 children undergoing hand surgery received axillary brachial plexus blocks with 0.5 ml.kg-1 of either 0.2% ropivacaine or 0.25% bupivacaine. Pain scores were noted at 0, 3, 6, 12 and 24 h after surgery. The time to first dose of codeine phosphate and the total doses of all analgesics given were recorded. RESULTS: There was no significant difference between the two groups in pain scores, the time to first dose of codeine phosphate or in analgesic requirements in the first 24 h. CONCLUSIONS: Ropivacaine 0.2% is as effective as bupivacaine 0.25% for axillary brachial plexus blocks in children undergoing hand surgery.

Adolescent↗

Proteoglycans in predentin: the last 15 micrometers before mineralization.

Small leucine-rich proteoglycans (SLRPs) regulate extracellular matrix organization. In order to investigate the distribution and potential functions of decorin, biglycan (BGN), and fibromodulin (3 SLRPs, potentially related to dentinogenesis), we performed light and electron immunochemistry on teeth from rats, and on wild-type and biglycan knockout mice (BGN KO). Immunohistochemical data demonstrate that chondroitin sulfate/dermatan sulfate (CS/DS) and keratan sulfate (KS) distributions displayed reverse gradients in predentin. The decrease of CS/DS labeling from the proximal to the distal predentin contrasted with the sharp decorin increase observed in the distal predentin near the predentin/dentin transition, an effect possibly attributable to the deglycosylation action of stromelysin-1. In contrast, BGN concentration was apparently constant throughout the whole predentin. Additional immunolabelings showed, for the first time, the presence of fibromodulin in predentin. Compared with the wild-type mouse, the mean diameter of collagen fibrils in the BGN KO was smaller in the proximal predentin but larger in the central and distal predentin, the metadentin was broader, and the dentin mineralization appeared altered and heterogeneous. Altogether, our data suggest an important role for BGN in dentin formation and mineralization.

Animals↗

Cloning, expression and characterization of the CHO cell elongating factor (Cef) from Vibrio cholerae O1.

CHO cell-elongating factor (Cef) is a recently identified putative virulence factor of Vibrio cholerae. Our previous studies show that this 85 kDa protein elongates CHO cells, causes fluid accumulation in suckling mice and has esterase activity. In this study, the cef gene was cloned in Escherichia coli using a yeast vector and subsequently expressed in the yeast Pichia pastoris. The cef genes from V. cholerae candidate vaccine strains JBK 70 and CVD 103-HgR were sequenced and found to be nearly identical (100 and 99.9% respectively) with an open reading frame (ORF) from the published sequence of V. cholerae N16961. Cloned toxin was purified to homogeneity in 3 steps using anion exchange, hydrophobic interaction and gel filtration chromatography. The size of cloned Cef on SDS-PAGE gels was 114 kDa. The increased size was probably due to glycosylation by the yeast since cloned protein reacted strongly with a glycoprotein stain. The cloned protein could not be directly sequenced, but when treated with trypsin, yielded a protein fragment with an amino acid sequence that matched the sequence predicted for the Cef protein. The purified cloned protein had esterase and CHO cell activity, but no suckling mouse activity.

Animals↗

Prime-boost: the way forward for recombinant vaccines against apicomplexan parasites. A Theileria perspective.

A good CD8+ response is required for immunity to many intracellular pathogens. Traditional antigen delivery using isolated sub-units or killed pathogens and adjuvant stimulates strong antibody responses but weak T-cell reactivity. Attenuated vaccines are usually more effective. The prime-boost delivery system based on immunisation with a naked DNA antigen-gene construct followed by boosting with an attenuated vaccinia virus expressing the same antigen is proving to be a powerful way to stimulate antigen-specific CD8 responses. Success using single epitopes is possible in malaria and we believe this approach holds much promise for other apicomplexan parasites such as Theileria spp.

Animals↗

The dentino-enamel junction revisited.

The dentino-enamel junction is not an simple inert interface between two mineralized structures. A less simplistic view suggests that the dentino-enamel junctional complex should also include the inner aprismatic enamel and the mantle dentin. At early stages of enamel formation, fibroblast growth factor (FGF)-2 is stored in and released from the inner aprismatic enamel, possibly under the control of matrix metalloproteinase (MMP)-3. The concentration peak for MMP-2 and -9 observed in the mantle dentin coincided with a very low labeling for TIMP-1 and -2, favoring the cross-talk between mineralizing epithelial and connective structures, and as a consequence the translocation of enamel proteins toward odontoblasts and pulp cells, and vice versa, the translocation of dentin proteins toward secretory ameloblasts and cells of the enamel organ. Finally, in X-linked hypophosphatemic rickets, large interglobular spaces in the circumpulpal dentin were the major defect induced by the gene alteration, whereas the mantle dentin was constantly unaffected. Altogether, these data plead for the recognition of the dentino-enamel junctional complex as a specific entity bearing its own biological characteristics.

Aging↗

A systematic approach to erectile dysfunction in the cardiovascular patient: a Consensus Statement--update 2002.

Sexual activity is no more stressful to the heart when compared with a number of other natural daily activities, e.g. walking one mile on the level in 20 minutes. The cardiac risk of sexual activity in patients diagnosed with cardiovascular disease is minimal in properly assessed and advised patients. Erectile dysfunction (ED) is extremely common, affecting over half of men aged 40-70 years, and increases in frequency with age. ED and cardiovascular disease share many of the same risk factors and commonly coexist. ED in the otherwise asymptomatic man may be a marker for underlying coronary artery disease. ED in the diagnosed cardiovascular patient should be identified by routine questioning in general practice. Modern therapies can restore a sexual relationship in the majority of patients with ED and can lead to a substantial improvement in quality of life. The majority of patients assessed to be at low or intermediate cardiac risk, as defined later in this paper, can be effectively managed in primary care. Primary care treatment for ED in patients defined as high risk can be initiated following a specialist opinion and/or confirmation that the patient's cardiovascular condition is stabilised. There is no evidence that currently licensed treatments for ED add to the overall cardiovascular risk in patients with or without diagnosed cardiovascular disease. If one form of therapy is not effective, follow-up will identify the need for alternative approaches. The pro-active management of ED in the cardiovascular patient provides an ideal and effective opportunity to address other cardiovascular risk factors and improve treatment outcomes.

Activities of Daily Living↗

Pyrimidinylimidazole inhibitors of p38: cyclic N-1 imidazole substituents enhance p38 kinase inhibition and oral activity.

Optimization of a series of N-1-cycloalkyl-4-aryl-5-(pyrimidin-4-yl)imidazole inhibitors of p38 kinase is reported. Oral administration of inhibitors possessing a cyclohexan-4-ol or piperidin-4-yl group at N-1 in combination with alkoxy, amino(alkyl), phenoxy and anilino substitution at the 2-position of the pyrimidine was found to potently inhibit LPS-induced TNF in mice and rats. The selectivity of these new inhibitors for p38 kinase versus eight other protein kinases is high and in all cases exceeds that of SB 203580.

Administration, Oral↗

New use of a three-dimensional pellet culture system for human intervertebral disc cells: initial characterization and potential use for tissue engineering.

STUDY DESIGN: Human intervertebral disc cells were cultured in a new three-dimensional "pellet culture" system as an alternative to conventional alginate bead microspheres. Histologic, biochemical, and immunohistologic assays were performed to characterize this new culturing method for disc cells. The feasibility of using the pellet culture system to study effects of gene therapy was also assessed. OBJECTIVES: To characterize a new and simpler, three-dimensional culture system for human intervertebral disc cells and to assess the feasibility of its use for gene therapy and tissue engineering studies. SUMMARY OF BACKGROUND DATA: The alginate microsphere three-dimensional culture system has been the most utilized culture method for disc cells, but it is technically difficult and has some disadvantages. Recently, the "pellet culture" method, a simpler three-dimensional culture system, was described for bone marrow stromal cells. This simpler method might be useful for in vitro and in vivo studies of disc cells as well as for delivery of exogenous genes. METHODS: Isolated human intervertebral disc cells were centrifuged at low speeds to form aggregates and allowed to grow as pellets for up to 3 weeks. At various times these pellet cultures were analyzed grossly, histologically, and immunohistologically. Their ability to incorporate [35S]sulfate in their response to TGF-beta1 was also analyzed. The ability of these pellets to deliver and express exogenous genes in vivo was analyzed by implantation of pellet cultures in muscles of SCID mice. RESULTS: Within several days the intervertebral disc cells were able to form mature three-dimensional aggregates that were each well encapsulated by a fibrous capsule. These pellets successfully synthesized proteoglycan and collagen Type II matrix as determined by histology and immunohistochemistry. In response to TGF-beta1, the pellets increased synthesis of proteoglycan and collagen Type II. When implanted into thigh muscles of SCID mice, the pellets remained aggregated and expressed the beta-galactosidase marker gene in vivo for up to 2 weeks. CONCLUSIONS: The pellet culture system is a new and technically simple method to culture human intervertebral disc cells. The majority of the human intervertebral disc cells retained their native phenotype in this three dimensional system and expressed a marker gene both in vitro and in vivo. Thus, this pellet system might be useful for in vitro and in vivo biochemical studies as well as for studies involving gene therapy and tissue engineering.

Adult↗