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Biomedical subjects

M E Ryan

Publications and source records attributed to M E Ryan.

At least 55 records · Page 3Linked to original sources
PubMed1996

Matrix metalloproteinases and their inhibition in periodontal treatment.

Matrix metalloproteinases (MMPs), produced by both infiltrating and resident cells of the periodontium, play a role in physiologic (e.g., tooth eruption) and pathologic (e.g., periodontitis) events. The evidence for the role of MMPs in periodontal destruction has accumulated over three and a half decades, and it is now recognized that an imbalance between activated MMPs and their endogenous inhibitors leads to pathologic breakdown of the extracellular matrix during periodontitis. This understanding has stimulated the search for a number of synthetic inhibitors that could be used as potential therapeutic agents. Tetracycline analogues, as proteinase inhibitors, are currently closer to being used clinically than any other agents in periodontal therapy. Other MMP inhibitors, such as Batimastat (British Bio-technology, Oxford, UK), are currently being tested clinically for inhibition of cancer metastasis and other diseases. Multiple mechanisms of MMP inhibition by tetracycline analogues have been proposed. The nonantimicrobial chemically modified tetracyclines are potent inhibitors of MMPs, preventing collagen breakdown and alveolar bone loss in animal models of periodontitis. In addition, nonantimicrobial low doses of the commercially available semisynthetic tetracycline doxycycline, have been used in human clinical trails to reduce MMP activity in the gingival crevicular fluid and gingival tissues, with a resultant reduction in pocket depth and attachment loss. Of particular interest, periodontal research on the nonantimicrobial properties of tetracycline has generated new therapeutic approaches to a variety of medical disorders characterized by excess MMP activity.

Alveolar Bone Loss↗
PubMed1996

Local and systemic factors in periodontal disease increase matrix-degrading enzyme activities in rat gingiva: effect of micocycline therapy.

We previously reported that both local and systemic factors relevant to the pathogenesis of periodontal disease can increase gingival collagenase activity in rats. Since the degradation of extracellular matrix is an essential feature of periodontal disease and this tissue breakdown requires multiple enzyme interactions, the current study was carried out to determine the effects of bacterial endotoxin (LPS) (a local factor) and diabetes (a systemic factor) on a panel of matrix-degrading enzymes (collagenase, gelatinase, elastase, and beta-glucuronidase) in the gingiva of rats. In addition, the effects of therapy with a semisynthetic tetracycline (minocycline) were investigated. Ten male, Sprague-Dawley rats were made diabetic by IV injection of streptozotocin. Four of the ten rats then received minocycline (10 mg/day) by oral gavage on a daily basis for 3 weeks. Nineteen nondiabetic rats served as controls and 9 of them received 10 microliters of E. coli LPS (10 mg/ml) by injection into the labial gingiva every other day during the last week of the study. The other 10 nondiabetic rats were sham injected with saline into the gingiva. At the end of the 3 week experimental period, gingival tissue and skin were dissected from each rat and extracted for enzyme analysis. Our results showed that diabetes markedly increased the four matrix-degrading enzyme activities in both gingiva and skin. In contrast, local LPS injection increased these enzyme activities in the gingiva alone. Systemic therapy with minocycline completely ameliorated these elevated enzyme levels in diabetic rats in both gingiva and skin. Minocycline added in vitro to the enzyme assay systems containing skin extract from diabetic rats also inhibited collagenase and gelatinase activities, but no inhibition was observed for elastase and beta-glucuronidase activities, indicating that the MMPs and other enzymes were inhibited by minocycline, during diabetes, by indirect and indirect mechanisms, respectively.

Alveolar Bone Loss↗
PubMed1995

Streptococcal preseptal cellulitis complicated by the toxic Streptococcus syndrome.

BACKGROUND: After decades of decline in the incidence of severe infections secondary to group A streptococci, a dramatic increase in the frequency and severity of infections with these organisms has been reported since 1984, including a "toxic Streptococcus syndrome," resembling staphylococcal toxic shock syndrome. To the authors' knowledge, this entity has never been described after ocular infection. METHODS: In a previously healthy 3-year-old boy, preseptal cellulitis developed secondary to minor trauma to the eyelid, progressing rapidly to hypotension, respiratory distress, and an erythrodermic desquamating rash. Ocular and blood cultures grew group A beta-hemolytic streptococci. Appropriate antibiotic coverage and management of systemic manifestations led to rapid improvement, although necrosis developed in the right upper anterior eyelid, requiring skin grafts. RESULTS: More than 3 years since the incident, the patient is free of infection and has a good cosmetic result after skin grafting and revisions for scarring and adhesions. CONCLUSIONS: Streptococcal preseptal cellulitis is not unusual, particularly after trauma. Ophthalmologists must be aware of the re-emergence of more virulent organisms with increased potential for morbidity and mortality.

Anti-Bacterial Agents↗
PubMed1995

Measuring patient satisfaction: a case study.

Health care providers are under tremendous pressure to meet consumer demands in order to compete in the rapidly changing health care arena. Through evaluating patient satisfaction, health care providers can learn what the consumer wants from the health care system. This article informs the reader of issues surrounding patient satisfaction data collection instruments, especially the problem of lack of standardization. That is, each instrument measures satisfaction according to different standards. This article presents a case study analysis of one patient satisfaction data collection instrument entitled the Picker-Commonwealth Survey on Patient-Centered Care. Suggestions for revision and further work are addressed.

Adult↗
PubMed1995

Pitfalls in HIV testing. Application and limitations of current tests.

Enzyme-linked immunosorbent assay (ELISA) and Western blot assay are the most commonly used laboratory tests for HIV infection. Both detect antibodies to HIV. ELISA results are based on detection of antigen-antibody complexes by using antibodies labeled with an enzyme that produces a color change in the presence of a specific substrate. Currently licensed ELISA tests have greater than 98% sensitivity and specificity for HIV. Western blot analysis detects antibodies to specific HIV antigens and is best used as a confirmatory test. In spite of the high sensitivity and specificity of both tests, false-positive and false-negative results do occur. Physicians should be aware of specific causes of inaccurate results. In individual cases, knowledge of the patient's history and the criteria used by the laboratory performing the test is important.

AIDS Serodiagnosis↗
PubMed1994

Efficacy and safety of aerosolized ribavirin in young children hospitalized with influenza: a double-blind, multicenter, placebo-controlled trial.

We randomly assigned children hospitalized with influenza who had been ill < or = 48 hours and who had a temperature > or = 37.8 degrees C to receive either ribavirin or placebo. All patients had evaluations performed for fever reduction, use of acetaminophen for temperature > or = 38.3 degrees C, duration and severity of influenza symptoms, and feeding behavior. Sixty-two patients (35 in the placebo group, 27 in the ribavirin group) had a diagnosis of influenza confirmed by laboratory study. The groups did not differ significantly in age, initial signs and symptoms, or in distribution of influenza A or B infections. The time to reduction of temperature < or = 38.3 degrees C for the ribavirin group was 8.9 hours compared with 22.6 hours for the placebo group (p = 0.04). The mean duration of acetaminophen use was 7.4 hours in the ribavirin group and 16.3 hours in the placebo group (p = 0.14). There were no significant differences between the groups in outcome of respiratory rate, pulse rate, cough, or level of consciousness. Convalescent influenza antibody geometric mean titer for the placebo group was 9.8 compared with 3.6 for the ribavirin group (p = 0.04). Ribavirin was more effective than placebo in accelerating normalization of temperature but there were no other significant differences.

Acetaminophen↗
PubMed1994

Clinical virology in children.

Virology has become an increasingly important field of medicine in the past decade. Many infectious diseases that were once of unknown etiology can now be linked to the specific viral pathogen. New methods for diagnosing and treating viral diseases are being developed. In addition, antiviral therapy or prophylaxis is available for many of these viral illnesses. This article reviews the basic medical aspects of some viral infections. Human parvovirus B19 causes erythema infectiosum, with the classic "slapped-cheek" rash. Human herpesvirus type 6 is thought to be the cause of roseola infantum, characterized by the familiar macular/maculopapular rash on the trunk and arms. Varicella-zoster virus infection results in chickenpox, which in the future may be prevented by a vaccine. Herpes simplex virus-1 causes up to 90 percent of oral and labial herpes infections. Congenital cytomegalovirus infection results in birth defects. Epstein-Barr virus is the primary cause of mononucleosis. Human papillomavirus causes laryngeal and genital warts. Respiratory syncytial virus is the major cause of lower respiratory tract disease in children. Rotavirus is the common agent in childhood diarrhea.

Child↗
PubMed1993

Platelet-derived growth factor and dexamethasone combined with a collagen matrix induce regeneration of the periodontium in monkeys.

Platelet-derived growth factor (PDGF) and the glucocorticoid dexamethasone combined with a collagen carrier matrix (CM) induced regeneration of the periodontium in monkeys. Regeneration was stringently defined as: (1) new cementum, (2) new supra-crestal bone extending coronally from the residual alveolar interdental septum and (3) functionally-oriented periodontal ligament fibers attaching new cementum to new bone. A single application of PDGF/dexamethasone/CM or CM was placed in debrided lesions of experimental periodontitis displaying 3-5 mm of attachment loss associated with horizontal and angular bony defects. Regeneration, judged histologically by these criteria and quantified by computer assisted histomorphometry after 4 weeks, was present only in PDGF/dexamethasone/CM treated lesions and not in those treated with CM or debridement alone. PDGF/dexamethasone/CM induced 5-fold more new cementum and ligament, and 7-fold more supra-crestal bone than control treatments. The presence of substantial amounts of regenerated periodontium including increased height of the alveolar bone; fill of vertically resorbed interdental alveolar septa in PDGF/dexamethasone/CM treated lesions suggests that this combination may provide a new therapeutic agent for the regeneration of lesions of periodontitis associated with horizontal as well as angular bony defects.

Alveolar Process↗
PubMed1992

Synergistic effects of dexamethasone on platelet-derived growth factor mitogenesis in vitro.

Platelet-derived growth factor (PDGF) and insulin-like growth factor-I (IGF-I) interact to stimulate proliferation of fibroblasts in culture. Glucocorticoids variably effect the response of cultured fibroblasts to polypeptide growth factors. This study determined the effects of dexamethasone on growth-factor stimulation of gingival, periodontal ligament and pulp fibroblast proliferation in vitro. Cultures of quiescent, low-passage, human fibroblasts were treated for varying periods of time with transforming growth factor-beta 2 (TGF-beta 2), PDGF and IGF-I: (1) alone, (2) in combination with each other, (3) singly plus dexamethasone, (4) in combination plus dexamethasone. Combinations of human, recombinant PDGF and IGF-I (10-1000 ng/ml) induced significantly higher rates of cell proliferation than either factor alone. Dexamethasone at doses ranging from 10(-5) to 10(-8) M substantially enhanced cell proliferation induced by these combinations and by PDGF without IGF-I but not IGF-I alone. By 6 days after a single application, 2-3 times as many cells were present in the PDGF and dexamethasone cultures as compared to PDGF without IGF-I. TGF-beta 2 specifically blocked the effects of dexamethasone added to PDGF-stimulated cells. Collagen and non-collagenous protein synthesis was not affected by the addition of PDGF and IGF-I with or without dexamethasone. These data suggest that dexamethasone may substitute for IGF-I in PDGF stimulation of cell proliferation.

Cell Division↗
PubMed1992

Employer evaluations of nurse graduates: a critical program assessment element.

Accountability in higher education dictates implementation of a comprehensive evaluation plan. Employer evaluation of graduates is an important component of program evaluation and contributes a different view that is rarely reported in the literature. The purpose of this study was to establish a database by surveying employers of baccalaureate-prepared nurses, postgraduation, over a five-year period. Employer surveys measured perceptions of graduates' functioning. Findings indicated that graduates function above expected levels for leadership skills, nursing skills, communication skills, and professionalism. Systematic program evaluation by employers is recommended at one and five years after graduation. A tool for employer evaluation of baccalaureate graduates is discussed.

Curriculum↗
PubMed1991

Integrating HIV/AIDS policies and curricular content into baccalaureate nursing programs.

A model used by one school of nursing to implement HIV/AIDS policies, sequenced instructional opportunities, and a research-based evaluation process is described. In the evaluation phase, a study was undertaken to measure students' retention of HIV/AIDS knowledge and their application of universal precautions (U.P.). Findings revealed that 59% of junior baccalaureate nursing students and 75% of seniors retained knowledge about HIV/AIDS and U.P. Seniors indicated that in their role as nursing student or technician/extern, supplies and equipment were readily available and that they had sufficient time to implement U.P. However, only 64% admitted to following correct procedures, even though 96% acknowledged feeling confident in their ability to do so. Knowledge about HIV/AIDS and consistent application of U.P. protects nursing students, prevents legal problems, and promotes the quality of patient care.

Clinical Competence↗
PubMed1989

Cholangitis due to Blastomyces dermatitidis.

A 70-yr-old woman presented with nonspecific complaints and had findings of a cholestatic liver enzyme pattern and a dilated left intrahepatic ductal system by radiographic imaging. Endoscopic retrograde cholangiopancreatography revealed multiple irregular flat stones and a fixed filling defect of the left hepatic duct. At the time of surgery a stonelike lesion of this ductal orifice was found along with a miliary pattern of infection of the left liver lobe. Histologic and microbiologic studies confirmed an infection by Blastomyces dermatitidis. Therapy with amphotericin B resulted in eradication of this infection. Despite their rarity, fungal infections of the biliary tree need to be considered in the differential diagnosis of biliary tract disease in the elderly and immunocompromised patient.

Aged↗