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Biomedical subjects

S J Bowman

Publications and source records attributed to S J Bowman.

At least 19 recordsLinked to original sources
PubMed2001

Ectopic expression of the B cell-attracting chemokine BCA-1 (CXCL13) on endothelial cells and within lymphoid follicles contributes to the establishment of germinal center-like structures in Sjögren's syndrome.

OBJECTIVE: To test the hypothesis that the formation of ectopic germinal center (GC)-like structures in Sjögren's syndrome (SS) is associated with the ectopic expression of the constitutive lymphoid tissue-homing chemokines B cell-attracting chemokine 1 (BCA-1; or, CXCL13) and stromal cell-derived factor 1 (SDF-1; or, CXCL12). METHODS: Immunohistochemical and immunofluorescence analysis was used to determine the expression of the constitutive chemokines BCA-1 (CXCL13) and SDF-1 (CXCL12) in salivary glands from 5 SS patients and 3 non-SS patients. In addition, the expression of their respective receptors (CXCR5 and CXCR4) was examined on infiltrating lymphocytes. Human tonsil was used as a positive control for secondary lymphoid tissue. RESULTS: BCA-1 (CXCL13) was expressed within lymphoid aggregates in SS, which shared many structural features with GCs in tonsil. BCA-1 (CXCL13) was completely absent in control biopsy samples from patients who did not have SS. High levels of BCA-1 (CXCL13) were also found on endothelial cells in salivary glands from SS patients. Diseased SS tissue was infiltrated by CXCR5-expressing B cells which organized into GC-like clusters. In complete contrast, SDF-1 (CXCL12), a constitutive chemokine involved in leukocyte retention within lymphoid tissue, was expressed by epithelial cells in both diseased and control samples. The chemokine receptor for SDF-1, CXCR4, was expressed on T cells that accumulated in a periductal distribution in diseased tissue. CONCLUSION: The ectopic expression of BCA-1 (CXCL13) on endothelial cells and within GC-like structures, together with the strong expression of SDF-1 (CXCL12) on ductal epithelial cells, is a unique feature of inflamed glands in SS. By creating a local microenvironment supportive of focal B cell aggregation and differentiation, with structural features that are remarkably similar to GCs, BCA-1 (CXCL13) and SDF-1 (CXCL12) may contribute to the excessive production of high-affinity, class-switched autoantibodies and to the high incidence of B cell lymphomas classically associated with SS.

B-Lymphocytes↗
PubMed2001

Posttreatment evaluation of the distal jet appliance.

This study analyzed molar distalization with the distal jet appliance, its effect on the anchor teeth, and the outcome at the completion of orthodontic treatment. Pretreatment, after distalization, and posttreatment lateral cephalometric radiographs were evaluated for 21 adolescent girls and 12 adolescent boys. The mean age of the subjects at the time of the pretreatment radiograph was 12.8 +/- 2.2 years. The mean time for the correction of the Class II molar relationship was 6.7 +/- 1.7 months, and the mean total treatment time was 25.7 +/- 3.9 months. The results of this study showed that the distal jet appliance distalized the maxillary molars, but there was significant loss of anchorage. The distal jet also showed less tipping of the maxillary molars and better bodily movement of molars because the force was applied closer to the center of resistance. The observations of treatment outcome indicate that the 1.8-mm mean net anterior movement of the maxillary first molar was more than offset by the 4.8-mm mesial movement of the mandibular first molar. There was no significant increase in lower face height. Consequently the effect on the facial balance was negligible.

Adolescent↗
PubMed2001

Facial aesthetics in orthodontics.

Current trends in orthodontic care emphasise alternatives to the extraction of premolars, despite a lack of support from the refereed literature for many of the non-extraction treatments. Anecdotal reports published in non peer-reviewed journals have called into question the aesthetic effects of extraction treatment. As calls for evidence-based treatments increase throughout dentistry, reports on the effects--both positive and negative--of different orthodontic options have appeared in growing numbers. Given the results of a variety of reports in the peer-reviewed literature, it may be concluded that orthodontic treatment involving extractions can produce improved aesthetics for many patients who have some combination of crowding and protrusion. However, careful diagnosis followed by evidence-based treatment decisions should be the accepted clinical norm as the specialty of Orthodontics embarks on its second century.

Esthetics↗
PubMed2000

The esthetic impact of extraction and nonextraction treatments on Caucasian patients.

This investigation was designed to compare the esthetic effects of extraction and nonextraction treatments. Panels of 58 laypersons and 42 dentists evaluated randomly presented pre- and posttreatment profiles of 70 extraction and 50 nonextraction Class I and II Caucasian patients. The samples were similar at the outset; however, at the end of treatment, the extraction patients' faces were, on average, 1.8 mm "flatter" than the faces of nonextraction subjects. The flatter faces were preferred by both panels, dentists more so than laypersons. In general, nonextraction treatment was seen as having little effect on the profile, whereas the perceived effect of extraction treatment was a statistically significant function of initial soft tissue protrusion-the greater the initial protrusion, the greater the benefit. The point at which a reduction in protrusion produces a perceived improvement was explored by way of regression analysis. Both panels saw extraction as being potentially beneficial when the lips were more protrusive than 2 to 3 mm behind Ricketts' E-plane. It is concluded that extraction treatment can produce improved facial esthetics for many patients who present with some combination of crowding and protrusion.

Adolescent↗
PubMed2000

Class II combination therapy (distal jet and Jasper Jumpers): a case report.

Class II combination therapy is a method that combines orthodontic and orthopedic mechanics in a single stage of treatment. Molar distalization is followed by fixed functional mechanics to reduce the dependence upon patient compliance while seeking more predictable completion of Class II correction.

Activator Appliances↗
PubMed1999

More than lip service: facial esthetics in orthodontics.

BACKGROUND: Current trends in orthodontic care emphasize alternatives to the extraction of premolars, despite a lack of support from the refereed literature for many of the nonextraction treatments. DESCRIPTION OF THE SITUATION: Anecdotal reports published in non-peer-reviewed journals have called into question the esthetic effects of extraction treatment. As calls for evidence-based treatments increase throughout dentistry, reports on the effects--both positive and negative--of different orthodontic options have appeared in growing numbers. CLINICAL IMPLICATIONS: Given the results of a variety of reports in the peer-reviewed literature, it may be concluded that orthodontic treatment involving extractions can produce improved esthetics for many patients who have some combination of crowding and protrusion. However, careful diagnosis followed by evidence-based treatment decisions should be the accepted clinical norm as the specialty of orthodontics embarks on its second century.

Esthetics, Dental↗
PubMed1997

T cell receptor alpha-chain and beta-chain junctional region homology in clonal CD3+, CD8+ T lymphocyte expansions in Felty's syndrome.

OBJECTIVE: Up to 42% of patients with Felty's syndrome (FS) have peripheral blood expansions of CD3+,CD8+ large granular lymphocytes (LGLs). The aim of this study was to determine whether the T cell receptor (TCR) alpha- and beta-chain sequences of these expansions from different patients have features in common that would support the hypothesis of an antigen-driven process. METHODS: Extraction of RNA from peripheral blood lymphocytes followed by synthesis of complementary DNA, inverse polymerase chain reaction (PCR) with TCR-specific primers, bacteriophage transformation, and sequencing of PCR products. RESULTS: Structural analysis of TCR beta-chain usage in such patients demonstrated a junctional region motif comprising the amino acids -LG- or -RG- in 7 of 14 clonal sequences and the motif -GXG- in 8 of 14. A biased alpha-chain junctional region usage of a hydrophobic and/or basic amino acid at position 2 was seen in 5 of 8 expanded sequences. These features differed significantly from control sequences. CONCLUSION: Given current models of TCR-peptide-major histocompatibility complex interaction, these observations are consistent with an antigen-driven, rather than a superantigen-driven, process in at least a subgroup of patients with FS.

Aged↗
PubMed1996

Large granular lymphocyte expansions in Felty's syndrome have an unusual phenotype of activated CD45RA+ cells.

One-third of patients with Felty's syndrome (FS) have significant clonal expansions of CD3+ CD8+ large granular lymphocytes (LGLs) in their peripheral blood. The reasons for this are unclear, but one hypothesis is that they are activated antigen-specific cells of pathogenic relevance. Cytofluorographic analysis of activation markers demonstrated that the cell surface phenotype of these expansions was CD57+, HLA-DR+, IL-2R-, Leu-8+, CD69+, LFA-1+, ICAM-1+, VLA-4+, i.e. 'activated' T cells. However, they also expressed the phenotype CD45RA+, CD45RBbright, CD45RO-, usually associated with 'naive' cells. This could result from aberrant activation, malignant transformation or from a 'reversal' of CD45 phenotype following chronic antigenic stimulation. In three patients with RA and non-clonal LGL expansions, a more variable phenotype was found. In one of these patients, the expanded population was identified in the peripheral blood, but not the synovial fluid. This may suggest that, at least in this individual, any pathogenic effect is exerted systemically.

Aged↗