PubMed Health⌕ Search

Biomedical subjects

S D London

Publications and source records attributed to S D London.

At least 19 recordsLinked to original sources
PubMed2007

High glucose-boosted inflammatory responses to lipopolysaccharide are suppressed by statin.

BACKGROUND AND OBJECTIVE: It has been established that periodontal diseases are more prevalent and of greater severity in diabetic patients than in nondiabetic patients. Recent studies have underscored the role of monocytes and macrophages in periodontal tissue inflammation and destruction in diabetic patients. Although it has been shown that monocytes isolated from diabetic patients produce more inflammatory cytokines and that gingival crevicular fluid collected from diabetic patients contains higher levels of inflammatory cytokines than that obtained from nondiabetic patients, the underlying mechanisms are not well understood. MATERIAL AND METHODS: U937 histiocytes cultured in medium containing either normal (5 mM) or high (25 mM) glucose were treated with 100 ng/ml of lipopolysaccharide for 24h. After the treatment, cytokines in the medium and cytokine mRNA in the cells were quantified using enzyme-linked immunosorbet assay and real-time polymerase chain reaction, respectively. RESULTS: In this study, we demonstrated that the pre-exposure of U937 histiocytes to high glucose concentrations markedly increased the lipopolysaccharide-induced secretion of pro-inflammatory cytokines and chemokines and the cellular inducible nitric oxide level compared with pre-exposure to normal glucose. Our data also showed that the increased secretion of cytokines was a result of increased mRNA expression. Furthermore, the effects of statin and peroxisome proliferators-activated receptor agonists on high glucose-enhanced secretion of cytokines were determined. The results showed that simvastatin, but not fenofibrate or pioglitazone, inhibited high glucose-enhanced cytokine release. CONCLUSION: This study has shown that high glucose concentrations and lipopolysaccharide act synergistically to stimulate the secretion of inflammatory mediators, and that statin is capable of suppressing the high glucose-boosted proinflammatory response. This study therefore delineates a novel mechanism by which hyperglycemia enhances the inflammatory responses of macrophages and suggests that statin may be useful in the treatment of periodontal disease in diabetic patients.

Chemokines↗
PubMed2001

Microbiology of chronic frontal sinusitis.

OBJECTIVES: To determine bacterial and fungal organisms that are present in patients undergoing surgery for chronic frontal sinusitis. STUDY DESIGN: Retrospective, nonrandomized study. METHODS: Retrospective, nonrandomized bacterial and fungal cultures were performed on 46 sinus aspirates obtained by frontal sinus trephination performed on 30 consecutive patients with chronic frontal sinusitis. RESULTS: Six patients were having sinus surgery for the first time, 19 patients had undergone prior functional endoscopic sinus surgery without instrumentation of the frontal sinus/recess, and the third group included 5 patients who had undergone prior frontal sinus/recess surgery. Preoperative computed tomography scan of the frontal sinuses revealed complete opacification in 63% (29/46 frontal sinuses) and partial opacification in 22% (10/46), and no data were available for 15% (7/46). Aerobic cultures revealed that 38% (13/35 cultures) had no growth, 21% (7/35) grew Staphylococcus aureus, 21% (7/35) grew coagulase-negative Staphylococcus, 9% (3/35) grew Haemophilus influenzae, and 26% (9/35) grew a variety of other organisms. Anaerobic cultures were positive in 3% (1/32) of sinuses, and fungal cultures were positive in 4% (1/24). Haemophilus influenzae was most common in primary cases, whereas coagulase-negative Staphylococcus was most common in patients undergoing revision frontal sinus surgery. There were no other significant differences between cultures from patients undergoing revision frontal sinus surgery, revision functional endoscopic sinus surgery without prior frontal surgery, and primary surgery. CONCLUSIONS: This study suggests that organisms involved in chronic inflammatory disease of the frontal sinus may change after previous sinus surgery. The study failed to support a significant role for anaerobes. The role for coagulase-negative Staphylococcus as a potential pathogen or a contaminating agent remains unclear.

Adult↗
PubMed2001

Reovirus triggers cell type-specific proinflammatory responses dependent on the autocrine action of IFN-beta.

Resident cells of the respiratory and gastrointestinal tracts, including epithelial and fibroblast cells, are the initial sites of entry for many viral pathogens. We investigated the role that these cells play in the inflammatory process in response to infection with reovirus 1/L. In A549 human bronchial or HT-29 human colonic epithelial cells, interferon (IFN)-beta, regulated on activation T cell expressed and secreted (RANTES), IFN-gamma-inducible protein (IP)-10, and interleukin-8 were upregulated regardless of whether cells were infected with replication-competent or replication-deficient reovirus 1/L. However, in CCD-34Lu human lung fibroblast cells, IFN-beta, IP-10, and RANTES were expressed only after infection with replication-competent reovirus 1/L. Expression of interleukin-8 in CCD-34Lu fibroblast cells was viral replication independent. This differential expression of IFN-beta, RANTES, and IP-10 was shown to be due to the lack of induction of IFN regulatory factor-1 and -2 in CCD-34Lu fibroblast cells treated with replication-deficient reovirus 1/L. We have shown that cytokine and/or chemokine expression may not be dependent on viral replication. Therefore, treatment of viral infections with inhibitors of replication may not effectively alleviate inflammatory mediators because most viral infections result in the generation of replication-competent and replication-deficient virions in vivo.

Autocrine Communication↗
PubMed2000

The use of bone morphogenetic protein gene therapy in craniofacial bone repair.

Bone morphogenetic proteins (BMPs) are capable of inducing endochondral bone formation when applied on biologic carriers in numerous mammalian in vivo assay systems. Bone morphogenetic protein gene therapy is also currently being developed to promote osteogenesis for clinical indications such as spinal fusions, craniofacial bone loss, and osteoporosis. In this study, critical-sized mandibular defects were treated with a control adenoviral vector (Ad-beta-gal), a BMP-2 adenoviral vector (Ad-BMP-2), or a BMP-9 adenoviral vector (Ad-BMP-9). Gross tissue examination, radiographic analysis, and histologic analysis demonstrated significant bony healing in the BMP treated groups compared to controls. Osteogenesis was limited to the bony defect, without extension into the surrounding soft tissues. The study suggests that with further development, BMP gene therapy may be potentially useful for repair of bony defects in the craniofacial region.

Animals↗
PubMed1999

Heterogeneous cytokine production by acutely stimulated bronchoalveolar T lymphocytes in reovirus 1/Lang-infected mice.

While the in vitro properties of CD4(+) and CD8(+) cytokine-producing lymphocytes have been well studied, the in vivo cytokine production patterns and relative roles of CD4(+) and CD8(+) T lymphocytes during a primary in vivo immune response remain unclear. In this study, mice were inoculated intranasally with reovirus 1/L, and respiratory T lymphocyte populations were analyzed using multicolor flow cytometric analysis for the production of cytokine within and between classical type 1/type 2 patterns. Cytokine production observed in vivo following infection did not correlate with classical T cell cytokine expression patterns; instead, multiple types of lymphocyte populations that produced one of several possible cytokine combinations were present. Cytokine production by CD4(+) lymphocytes appears in the early and middle stages of the immune response, while CD8(+) lymphocytes produce more cytokine in the later stages. Early cytokine responses occurred predominantly in the whole lung and lung-associated lymph node populations. The complex patterns of cytokine expression seen in this study likely influence local cell-mediated immunity as well as the complex interaction of T cell subsets and the interaction of T cells with B cells which are necessary for the generation of cell-mediated and humoral immune responses required for effective broad-spectrum immunity.

Animals↗
PubMed1999

Polychlorinated biphenyl mixtures (Aroclors) inhibit LPS-induced murine splenocyte proliferation in vitro.

The immune system is believed to be a sensitive indicator for adverse polychlorinated biphenyl (PCB)-induced health effects. Four commercial PCB mixtures (Aroclors) or six individual PCB congeners were evaluated for their effect on splenocyte viability and lipopolysaccharide (LPS)-induced splenocyte proliferation in vitro in two strains of mice, C57B1/6 (high affinity aromatic hydrocarbon receptor (AhR) complex) and DBA/J (low affinity AhR complex). All four Aroclors, the selected individual noncoplanar congeners, or two tertiary mixtures containing one congener from each class significantly decreased the in vitro LPS-induced proliferation of murine splenocytes in either strain of mice without inducing a significant decrease in viability. In contrast, selected individual coplanar or mono-ortho-coplanar congeners did not inhibit splenocyte proliferation or viability at any concentration. These results suggest that mixtures of PCBs and/or congener class (specifically, noncoplanar congeners) may be more highly immunotoxic than individual planar and mono-ortho-coplanar congeners alone. Thus, this in vitro assay has revealed a more complex pattern of immunotoxicity of Aroclors versus individual congeners than has previously been reported or anticipated based on both in vivo derived immunotoxic data and standard comparisons to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). These results have important practical significance since mixtures of PCB congeners were used industrially and now contaminate the environment.

Animals↗
PubMed1999

Optimal induction of upper respiratory tract immunity to reovirus 1/L by combined upper and lower respiratory tract inoculation.

There has been an increasing interest in developing vaccines which are both easy to administer and which elicit functionally protective immune responses at mucosal and/or systemic sites. Intranasally administered vaccines meet the criteria of ease of administration and are thought to stimulate respiratory-mucosal immunity via interaction with nasal associated lymphoid tissues (NALT). The aim of this study was to gain a better understanding of how best to stimulate respiratory-mucosal immunity using a murine model of respiratory reovirus infection. Either a predominantly upper respiratory tract infection or a combination upper and lower respiratory tract infection was established by administering the same virus dose in either a small or large inoculum volume. These studies demonstrate that stimulation of NALT alone by an upper respiratory tract infection does not induce an optimal primary antibody response even in the nasal cavity. Effective immunity of both the upper and lower respiratory tract was obtained when a combination upper and lower respiratory tract infection was established. These results have important clinical implications since they suggest that effective respiratory mucosal immunity will be best achieved by the combined stimulation of both the upper and lower respiratory tract and will likely require both intranasal as well as inhaled aerosol delivery of antigen to the lower respiratory tract in humans.

Administration, Intranasal↗
PubMed1999

Prolonged induction of IL-8 gene expression in a human fibroblast cell line infected with reovirus serotype 1 strain Lang.

Viruses which infect mucosal surfaces commonly infect these particular anatomical sites based on both the virion structure and the interaction of the virus with a particular microenvironment. We infected a human lung epithelial cell line, a human gut epithelial cell line, and a human lung fibroblast cell line with reovirus 1/L to explore how this natural isolate of both the lung and the gut may interact with mucosal surfaces. While reovirus infection of the gut and lung epithelial cell lines was lytic, a chronic infection was established in the human lung fibroblast cell line. All three cell lines also produced interleukin-8 (IL-8) after infection with reovirus 1/L, and IL-8 production was not dependent upon viral replication. A prolonged production of IL-8 was observed in the chronically infected lung fibroblast cell line, suggesting that this mucosal population may be involved in the generation of inflammatory responses after the resolution of the initial lytic infection of the epithelium. These studies provide an in vitro model system for analyzing the interaction of reovirus 1/L with resident mucosal cell populations.

Cell Line↗
PubMed1998

A nasal critical-size defect: an experimental model for the evaluation of facial osseous repair techniques.

OBJECTIVE: To create a standardized nonhealing defect of craniofacial, minimal load-bearing, endochondral type bone with geometric properties that are amenable to quantitative and biomechanical testing that can be used to develop new osteoconductive and osteoinductive engineering repair techniques. DESIGN: Before-and-after randomized trial of an anatomical description. SUBJECTS: Twenty-four retired male breeder Sprague-Dawley rats. METHODS: A standardized osseous defect was created by removing the nasal bones with a cutting burr to the level of the nasal mucosal membranes. The defects were not repaired, and groups of 8 animals were examined using planimetry, computed tomographic scanning, and histological analysis at 1, 3, and 6 months following surgery to quantify defect repair. RESULTS: Mean repair rate by surface area measurements at 1, 3, and 6 months was 5.75%, 4.89%, and 7.09%, respectively. Results from histological analysis revealed that the defects were filled with fibrous tissue. Computed tomographic scans showed the bone defect without repair. CONCLUSION: This nasal osseous defect fulfills criteria to be considered as a critical-size defect that can be used to investigate new techniques for bone reconstruction.

Animals↗
PubMed1998

Hyperbaric oxygen for the management of radionecrosis of bone and cartilage.

OBJECTIVES: To review the use of hyperbaric oxygen in the management of radionecrosis of the head and neck. STUDY DESIGN: A retrospective analysis of patients utilizing chart review and telephone interviews. All patients diagnosed with osteoradionecrosis and chondroradionecrosis of the head and neck and treated with hyperbaric oxygen at the University of Virginia are included. METHODS: Demographics, pretreatment data, and precipitating events were recorded. Outcomes were evaluated using a grading scale of symptomatology and physical examination as determined by the patient and physician. RESULTS: Sixteen patients with osteoradionecrosis and five with chondroradionecrosis were reviewed. All patients showed clinical improvement with decreased pain following HBO therapy. None of the patients with chondroradionecrosis required laryngectomies, and two of the four who were tracheotomy dependent were successfully decannulated. The patient and physician grading scores demonstrated moderate to significant improvement in both groups following therapy. CONCLUSION: The successful use of hyperbaric oxygen for the management of radionecrosis of the head and neck is supported. The unusual prevalence of chondroradionecrosis may be an early reflection of changes in treatment protocols for patients with head and neck cancer.

Adult↗
PubMed1997

Respiratory reovirus 1/L induction of intraluminal fibrosis. A model for the study of bronchiolitis obliterans organizing pneumonia.

Bronchiolitis obliterans organizing pneumonia (BOOP) is a term that was first applied in 1985 to describe a long-observed but unclassified pattern of acute lung injury. BOOP lesions are characterized by fibrous extensions into the alveolar spaces in association with a peribronchiolar organizing pneumonia. Since 1985, an increasing number of reports of BOOP have appeared in the clinical literature, and it is now accepted that BOOP is a significant pulmonary syndrome. Although BOOP can be associated with a number of documented pulmonary insults, many cases are not associated with known causes and are thus classified as idiopathic. The lack of an appropriate small animal model that closely mimics the generation of BOOP lesions has been an impediment to basic studies of the pathogenic mechanisms responsible for the generation of BOOP in humans. In this report, we describe an animal model for BOOP in which CBA/J mice infected with reovirus serotype 1/strain Lang develop BOOP lesions. These lesions closely resemble those seen in humans and occur in a well defined temporal sequence that proceeds from initial peribronchiolar inflammatory lesions to characteristic, fibrotic cellular BOOP lesions over a 3-week time course.

Animals↗
PubMed1996

Respiratory-mucosal lymphocyte populations induced by reovirus serotype 1 infection.

Respiratory virus infections are a serious health challenge. While models exist to study immune mechanisms of the respiratory tract, they have not allowed analysis of the interaction of the lower respiratory tract with other components of the mucosal immune system. This study demonstrates that reovirus 1/Lang, an effective gut mucosal immunogen, also provides a useful model of respiratory mucosal infection. Intra-nasal infection of Balb/c mice resulted in severe viral bronchopneumonia. Major components of the cellular inflammatory response in the lung interstitium and alveolar spaces were CD8 lymphocytes. Lung lymphocyte populations exhibited lysis of reovirus-infected, but not uninfected target cells after in vitro culture. The GCT antigen, a germinal center B-cell and CD8 T-cell marker, was present on 21-60% of the inflammatory lymphocytes. A novel population of GCT-expressing CD4+ lymphocytes unique to reovirus-stimulated lung alveolar and interstitial lymphocyte populations was identified.

Acute Disease↗
PubMed1996

Studies of determinants of glove hole puncture during electrosurgery.

Holes in surgical gloves are considered to be an important source of transmission of pathogens between patient and surgeon. The purpose of this study was to determine if electrosurgery could alter the integrity of latex surgical gloves. The effects of electrosurgery on 11 brands of commercially available latex surgical gloves were tested through an in vitro study that simulated the conditions in the operating room. Glove hole puncture was encountered only with coagulation current operating at the highest setting. In addition, maximal surface area contact with the hemostat to the glove surface was required to produce glove puncture. The presence of powder and glove hydration were not significant determinants of glove hole puncture. On the basis of our study, we believe that all surgical gloves tested offered the surgeon adequate protection at commonly used levels of cutting and coagulation current, as long as no breach existed prior to the donning of gloves.

Electrosurgery↗
PubMed1996

Experimental reovirus serotype 1/strain Lang infection of the lung: a model for the study of the lung in the context of mucosal immunity.

A number of studies have examined the nature of the respiratory immune response to particular pathogens. Although many pathogens stimulate specific immunity in the lung, they frequently are not effective immunogens at other mucosal sites. Because the gastrointestinal tract is a major inductive site for mucosal immunity, a pathogen that is an effective respiratory and gut immunogen would allow studies of the interaction of the lung with gut mucosal immune system. Reovirus, a respiratory isolate that previously has been shown to be an effective gut mucosal immunogen, provides a potential model of the relationship of the lung to the gut mucosal immune system. In this report, we demonstrate that intranasal application of reovirus serotype 1/strain Lang (1/L) to CD-1 mice elicits an acute lymphocytic inflammatory infiltration of the lung and hyperplasia of the lung-associated lymph nodes. The initial inflammatory response occurs in the airspaces and interstitium of the lung. As the infection progresses, the initially diffuse cellular infiltrate becomes more focused around small bronchioles. Viral replication occurs predominantly during the first week of the infection, and infectious virions are eliminated during the second week. After the elimination of infectious virions, a secondary response consisting of the appearance of plasma cells adjacent to pulmonary arteries develops as the primary infiltrate organizes into peribronchiolar follicles, resembling the human inflammatory lung condition termed follicular bronchiolitis. These two infiltration patterns were also observed by immunohistochemical analysis of the the infected lung. Whereas CD4+ and CD8+ lymphocytes and Mac-1+ cells were found to be more closely associated with the primary infiltration process, B220+ lymphocytes were observed adjacent to pulmonary arteries. These results establish respiratory reovirus 1/L infection as a viable model for future investigations of the mucosal immune response in the lung and its relationship to the common mucosal immune system.

Animals↗
PubMed1995

A retrospective analysis of 6,387 cholecystectomies.

This is the largest retrospective analysis of biliary tract surgery ever reported involving 6,378 patients operated on during a three year period, 1990-1992. During this time interval, the frequency of laparoscopic procedures has increased dramatically. The use of laparoscopic procedures was associated with a significant decrease in the total length of hospital stay and total charges as compared to the open procedures. Because of laparoscopic surgery's increased acceptance, we propose that the frequency of laparoscopic surgery of the biliary tract should be used as a quality control measure.

Aged↗