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C Stephens

Publications and source records attributed to C Stephens.

At least 73 records · Page 4Linked to original sources
PubMed1994

A computer-based orthodontic learning package: report of a trial.

Computer-based teaching has been used in the Department of Child Dental Health of the University of Bristol Dental School for almost 10 years to provide students with additional practice in the assessment of malocclusion and the planning of orthodontic treatment. In this article, the authors describe a study of the usefulness of computer-based learning packages for general practitioners and offer guidelines for others wishing to set up such a scheme.

Adult↗
PubMed1993

A molecular and serologic analysis of the major histocompatibility complex and complement component C4 in systemic sclerosis.

OBJECTIVE: To investigate the contributions of the major histocompatibility complex (MHC) and C4 alleles to systemic sclerosis (SSc), and to pulmonary fibrosis and autoantibody expression in SSc, by analysis at the DNA level. METHODS: One hundred fifteen patients with SSc were tested serologically for alleles of the class I MHC loci, and were tested for class II alleles (DRB, DQA, and DPB) by a combination of restriction fragment length polymorphism (RFLP) analysis and oligonucleotide probes with polymerase chain reaction amplification. C4 was studied by protein phenotyping and RFLP analysis in 80 patients. Correlations were made between disease status, pulmonary fibrosis, and expression of anticentromere antibodies (ACA) and anti-Scl-70. RESULTS: The C4A-null phenotype was found to provide the strongest disease association factor of the MHC region (P = 0.000064, relative risk [RR] = 2.8, etiologic fraction [EF] = 32.1). The primary MHC susceptibility allele was found to be DQA2 (Pcorr = 0.0009, RR = 2.5, EF = 35.6), which is in linkage disequilibrium with both DR3 and DR11. DR2 was protective, but only for female patients (P = 0.0021, RR = 0.42, protective fraction = 19.4). DR52a was the primary MHC allele associated with pulmonary fibrosis in SSc patients. Expression of ACA was associated with the presence of either DR1 or DR4 (P = 0.0015, RR = 6.7, EF = 78.0). Anti-Scl-70 expression correlated with an acidic residue of DP beta (DPB1:69:E) (P = 0.0063, RR = 4.6, EF = 53.1). CONCLUSION: Of all the potential markers of disease susceptibility analyzed, the C4A locus was the strongest. C4AQ0 and DQA2 are independent susceptibility factors for SSc. The development of pulmonary fibrosis in SSc patients can be predicted using combined MHC and autoantibody analysis. The MHC alleles associated with the expression of disease-specific autoantibodies are not markers for disease susceptibility.

Alleles↗
PubMed1993

Nitrogen balance in patients treated with extracorporeal membrane oxygenation.

Extracorporeal membrane oxygenation (ECMO) is a commonly used technique in the management of newborn respiratory failure. However, few studies have addressed the optimal nutritional support of these critically ill neonates. Eleven newborns undergoing ECMO for respiratory failure were studied at various levels of intravenous caloric and nitrogen intake, using nitrogen balance techniques, to assess optimal nutritional support necessary to achieve positive nitrogen balance. Nonprotein nitrogen calories > 60 kcal/kg/d, and nitrogen > 240 mg/kg/d were necessary to achieve positive nitrogen balance, while maximum positive balance was seen with nitrogen intake > 400 mg/kg/d. These data suggest that newborns treated with ECMO can achieve positive nitrogen balance with modest amounts of caloric and nitrogen intake.

Energy Intake↗
PubMed1993

Connective tissue disease and autoantibodies in the kindreds of 63 patients with systemic sclerosis. The United Kingdom Systemic Sclerosis Study Group.

Systemic sclerosis (SSc) tends to occur in a sporadic fashion and familial occurrence of the disease is unusual. Nevertheless, reports of related connective tissue diseases (CTD), autoantibodies, or both in family members together with associations of certain HLA class II phenotypes with SSc suggest that genetic factors might play a part in susceptibility to the disease. Because of the relative rarity of SSc only a small number of family pedigrees have been studied previously. This report represents the largest study to date, to our knowledge, of family members of patients with scleroderma, and provides the opportunity to investigate the relative importance of genetic and environmental factors operating in the disease. The family pedigrees of 63 patients with systemic sclerosis were examined with respect to clinical, serologic, and immunogenetic features. Multiple cases of SSc were seen only in 1 family, in which the disease affected a father and daughter. Disease expression in these 2 individuals was very similar both clinically and serologically; relatives with other connective tissue diseases were found in 9 families, and nonspecific features of CTD such as Raynaud phenomenon, and arthralgia or arthritis, occurred commonly, especially in female relatives. Antinuclear antibodies (ANA) were also detected more frequently in relatives than in controls. However, antibodies previously demonstrated to have a high degree of specificity for SSc were confined to patients with this disease. Probands had an increase in the frequency of HLA-DR3, DR5, and C4AQO. Patients with diffuse scleroderma had an increased frequency of HLA-DR3, while those with the limited form of the disease had an increased frequency of HLA-DR5.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1992

Policy directions in urban health in developing countries--the slum improvement approach.

The urban development, or housing, sector has a longer experience of addressing the problems of the urban poor in developing countries than the health sector. In recent years the policy of 'slum improvement', which involves both sectors, has attracted the support of international donors. This article documents the development of the slum improvement approach and addresses key issues of the approach which have implications for health planning: covering the poorest dwellers; relocation; land tenure; gentrification; debt burdens and the impact on women. Questions about the approach which still need answering are defined and a summary of the constraints in slum improvement and potential solutions is presented.

Developing Countries↗
PubMed1991

Fibronectin and VLA-4 in haematopoietic stem cell-microenvironment interactions.

The self-renewal and differentiation of haematopoietic stem cells occurs in vivo and in vitro in direct contact with cells making up the haematopoietic microenvironment. In this study we used adhesive ligands and blocking antibodies to identify stromal cell-derived extracellular matrix proteins involved in promoting attachment of murine haematopoietic stem cells. Here we report that day-12 colony-forming-unit spleen (CFU-S12)5 cells and reconstituting haematopoietic stem cells attach to the C-terminal, heparin-binding fragment of fibronectin by recognizing the CS-1 peptide of the alternatively spliced non-type III connecting segment (IIICS) of human plasma fibronectin. Furthermore, CFU-S12 stem cells express the alpha 4 subunit of the VLA-4 integrin receptor, which is known to be a receptor for the CS-1 sequence, and monoclonal antibodies against the integrin alpha 4 subunit of VLA-4 block adhesion of CFU-S12 stem cells to plates coated with the C-terminal fibronectin fragment. Finally, polyclonal antibodies against the integrin beta 1 subunit of VLA-4 inhibit the formation of CFU-S12-derived spleen colonies and medullary haematopoiesis in vivo following intravenous infusion of antibody-treated bone marrow cells.

Animals↗
PubMed1991

Subacute cutaneous lupus erythematosus--the annular variant. A histological and ultrastructural study of five cases.

Subacute cutaneous lupus erythematosus is an uncommon, non-scarring variant of lupus erythematosus which has received scant attention in the pathology literature. Its recognition as a distinct entity is important, as, although mild systemic features may be associated, there is characteristically a relative absence of life-threatening renal or central nervous systemic involvement. Subacute cutaneous lupus erythematosus may be clinically sub-divided into the more common annular and the rarer papulosquamous (psoriasiform) variants. A clinicopathological study of five cases of the annular variant is presented with a review of the literature. We highlight the histological and ultrastructural appearances. Discriminatory features from the other variants of lupus erythematosus and additional conditions with which it may be confused, including lichen planus and acute graft-versus-host disease, are discussed.

Adult↗
PubMed1991

Is rheumatoid arthritis in Indians associated with HLA antigens sharing a DR beta 1 epitope?

HLA class II antigens were identified in a group of 44 patients with rheumatoid arthritis (RA) originating largely from the north or northeast of the Indian subcontinent and resident now in east London. Compared with 67 locally typed east London Asian controls, the prevalence of three HLA-DR antigens was raised in the patients: DR1 18.2% v 6.0% chi 2 = 3.99, DR4 20.5% v 11.9% chi 2 = 1.48, and DRw10 27.3% v 8.9% chi 2 = 6.56. These differences were also found when the patients with RA were compared with a larger control group of 110 northern Indians: DR1 18.2% v 7.2% chi 2 = 4.02, DR4 20.5% v 7.2% chi 2 = 5.56, and DRw10 27.3% v 8.1% chi 2 = 9.7. Twenty five (57%) of the patients expressed at least one of these antigens. All patients were also characterised for HLA-Dw types by mixed lymphocyte culture typing. The prevalence of the HLA-DR4 associated Dw types in the patients was: Dw4 2.3%, Dw10 0%, Dw14 11.4%, and Dw15 6.8%. The DR beta 1 chains of DR1 and DRw10 together with the Dw types of DR4 other than Dw10 share amino acid residues in a region of the third hypervariable region considered to be critical in antigen presentation. It is concluded that RA in Indians is associated with these HLA antigens, and data from this study support the hypothesis of a cross reactive epitope common to HLA specificities associated with RA.

Arthritis, Rheumatoid↗
PubMed1991

Newly synthesized glycoconjugates from two cell lines derived from rat osteogenic sarcoma: effects of Matrigenin activity from bone.

An activity isolated from bovine bone was previously shown to stimulate proteoglycan synthesis by several connective tissue cell lines from normal tissues (Matrigenin activity). The effect of this activity on glycoconjugate synthesis by two osteoblastic cell lines, ROS 17/2 and UMR-106, derived from rat osteogenic sarcoma, was examined after labelling of the cells with [3H]glucosamine and [35S]sulfate. The glycoconjugates from the cell layers and the media were separated by DEAE-Sephacel chromatography and the anionic glycoconjugates of the media were further analyzed by chromatography on Sepharose CL-2B and enzymatic digestion of the papain-released glycosaminoglycans. The ROS 17/2 cells secreted at least two distinct species of proteoglycan (one heparan sulfate rich and the other chondroitin sulfate rich), whereas the UMR-106 secreted primarily an anionic glycoprotein. The addition of Matrigenin activity to the ROS 17/2 cells resulted in stimulation of incorporation of radioactivity into the proteoglycan and hyaluronic acid, but in UMR-106 cultures it resulted in decreased incorporation into the anionic glycoprotein. The decrease in incorporation into the anionic glycoprotein from the medium was shown, by alkaline beta-elimination, to have occurred mainly in the oligosaccharide fraction, relative to control cultures.

Animals↗
PubMed1991

Teaching problem handling in general practice: a computer assisted learning software package for medical students.

A computer assisted learning software package for medical students, EnMesh, designed to increase understanding of the problem-handling skills needed in general practice has been developed at the University of Liverpool. Users access the system anonymously and respond in sequence to problems in the form of clinical vignettes. Responses to each problem, in the form of up to six two-line text statements, are generated by the user with a simple word processing facility. Users compare their responses with those of established general practitioners, searching for similar or matching ideas. After completing not less than four problems users are provided with feedback on their performance in relation to the physical, psychological and social dimensions of the problems. The frequency with which the system is being used and the results of self scoring are monitored by a parallel teacher programme. The programmes are designed to run on a wide range of microcomputers. EnMesh was designed to provide an informal learning resource within an established clinical course. The challenge of valid problems, the option to respond anonymously, self scoring and feedback on performance are features designed to attract student participation in computer assisted learning. Although in EnMesh the expert data is categorized in three dimensions, in designing such software the number of categories is limited solely by the range of responses which feedback is required to reflect.

Computer-Assisted Instruction↗
PubMed1991

Urbanization and health in developing countries.

In developing countries the level of urbanization is expected to increase to 39.5% by the end of this century and to 56.9% by 2025. The number of people living in slums and shanty towns represent about one-third of the people living in cities in developing countries. This article focuses upon these poor urban populations and comments upon their lifestyle and their exposure to hazardous environmental conditions which are associated with particular patterns of morbidity and mortality. The concept of marginality has been used to describe the lifestyle of the urban poor in developing countries. This concept is critically examined and it is argued that any concept of the urban poor in developing countries being socially, economically or politically marginal is a myth. However, it can certainly be claimed that in health terms the urban poor are marginal as demonstrated by some of the studies reviewed in this article. Most studies of the health of the urban poor in developing countries concentrate on the environmental conditions in which they live. The environmental conditions of the urban poor are one of the main hazards of the lifestyle of poor urban residents. However, other aspects of their way of life, or lifestyle, have implications for their health. Issues such as smoking, diet, alcohol and drug abuse, and exposure to occupational hazards, have received much less attention in the literature and there is an urgent need for more research in these areas.

Developing Countries↗
PubMed1991

Complement activation during prolonged extracorporeal membrane oxygenation.

Short-term cardiopulmonary bypass activates the complement system, possibly resulting in pulmonary dysfunction from granulocyte aggregation and pulmonary endothelial damage. These effects may be inhibited by steroids. Prolonged extracorporeal membrane oxygenation (ECMO) is used for newborn respiratory failure, but the effects of ECMO on complement activation are unknown. Twenty-one newborn infants with respiratory failure treated with ECMO were randomly assigned to group I (control, no steroids) or group II (30 mg/kg intravenous methylprednisolone before ECMO). Depletion assays of C3 and C5 were performed in each group at intervals before and during ECMO (declining values indicate complement activation). The groups were compared for complement levels, survival, time on ECMO and on the ventilator, and total hospitalization time. Steroids significantly shortened the time on ECMO and time on the ventilator after ECMO but did not affect survival or total hospitalization time. Steroids also enhanced activation of C3 and C5. Complement activation occurs during ECMO. Steroid administration paradoxically causes earlier complement activation but shortens ECMO and ventilator times. Complement activation during ECMO is of questionable significance. The benefits of steroids during ECMO may be mediated through other mechanisms.

Birth Weight↗
PubMed1990

Prognostic determinants in extracorporeal membrane oxygenation for respiratory failure in newborns.

Extracorporeal membrane oxygenation (ECMO) is becoming an accepted therapeutic modality for newborn respiratory failure, but there is little information available regarding the prognostic determinants with this technique. One hundred thirty-five newborns treated with ECMO over a 4-year period were critically analyzed with regard to the influence that birth weight, gestational age, age at initiation of ECMO, best blood gases before ECMO, number of hours on ECMO, renal failure, intracerebral hemorrhage, and long-distance air transport had on survival. Infants with meconium aspiration and those undergoing long-distance transfer showed significant differences in blood gases before ECMO, with survivors having more normal pH and carbon dioxide tension values. Intracerebral hemorrhage and renal failure that developed during ECMO were grave prognostic signs, with few survivors in either group. These data show that ability to ventilate patients before ECMO, giving normal carbon dioxide tension and pH values, is an important prognostic sign in infants with meconium aspiration and undergoing long-distance transfer for ECMO, whereas renal failure and intracerebral hemorrhage are usually lethal complications of ECMO. Each center performing ECMO should continually reevaluate this invasive technique and its results and complications.

Acute Kidney Injury↗
PubMed1990

Holograms as substitutes for orthodontic study casts: a pilot clinical trial.

A pilot study of holograms as substitutes for study casts during routine clinical treatment was carried out by four clinicians on 56 patients over a 6-month period. Three of the clinicians found holograms to be as informative as study casts and equally or more convenient, but one clinician considered holograms to be inferior to study casts in both these respects. In addition, replicate quantification of malocclusions by means of the Summers index showed very similar rates of random error for holograms and for study casts and no significant systematic error between the scores obtained. Currently available holograms merit further investigation as alternatives to study casts. Refinement to further improve the convenience, informativeness, and economy of the holograms is also being undertaken.

Holography↗
PubMed1989

A critical analysis of extracorporeal membrane oxygenation for congenital diaphragmatic hernia.

Despite advances made in the care of infants with congenital diaphragmatic hernia (CDH), survival remains poor. New therapy, such as extracorporeal membrane oxygenation (ECMO), is controversial but may improve survival. Thirty-two newborns with CDH were treated. Thirteen infants were treated with jugular vein-carotid artery ECMO after CDH repair elsewhere; six (46%) survived. Three of the remaining 19 were moribund shortly after birth and first received ECMO, then underwent repair; two (67%) survived. The other 16 underwent CDH repair; 8 of 9 (89%) recovered with conventional therapy, and 4 of 7 (57%) survived when ECMO was used after conventional therapy failed. Overall survival was 63%. Parameters with which physicians may attempt to predict survival or the need for ECMO after repair--such as A-aDO2, ventilatory index versus PCO2, presence of a "honeymoon period" (PaO2 greater than 100 mm Hg after repair), or oxygenation index--were unreliable. ECMO can improve survival in infants with CDH, probably through reversal of pulmonary hypertension. Presently available methods of predicting survival after CDH repair with or without ECMO are not accurate, and thus no infant should be excluded from repair or ECMO support.

Extracorporeal Membrane Oxygenation↗