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Biomedical subjects

J M Lewis

Publications and source records attributed to J M Lewis.

At least 19 recordsLinked to original sources
PubMed2006

Cystoid macular oedema following pneumatic retinopexy vs scleral buckling.

AIMS: To determine the incidence of angiographic cystoid macular oedema (CMO) following pneumatic retinopexy (PR) and scleral buckling (SB) in consecutive case series. METHODS: Patients who had successful anatomical attachment following PR and SB were included in our study; 132 patients had PR and 121 patients had SB. We evaluated the demographic characteristics, visual acuity, lens status, macular status, and previous ocular history in all patients. CMO was evaluated by fluorescein angiography (FA) in a masked pattern, 6 and 12 weeks after surgery in all cases. We analysed the CMO incidence and its correlation with preoperative ocular status and visual outcome. Chi2 and Fisher's exact tests were used in statistical analysis. RESULTS: CMO was present in 15 of 132 (11%) PR, and 35 of 121 (29%) SB patients at 6 weeks (P=0.0005); the oedema was persistent in eight of 132 (6%) PR and 21 of 121 (17%) SB patients at 12 weeks (P=0.0005). Eight of 106 (8%) phakic and seven of 26 (27%) pseudophakic patients developed CMO following PR (P=0.02). In the SB group, 26 of 72 (36%) patients who had preoperative macular detachment developed CMO (P=0.03). Visual improvement was limited in patients who developed angiographic CMO despite anatomical re-attachment of the retina. CONCLUSIONS: CMO may occur following both PR and SB and deteriorate the visual outcome. Previous cataract surgery and macular detachment may increase the CMO rates following PR and SB, respectively.

Adult↗
PubMed2006

Oral toxicity study of 2-pentenenitrile in rats with reproductive toxicity screening test.

A combined repeated-dose toxicity study with reproduction was conducted with 2-pentenenitrile (2-PN). Rats (10/sex per dose level) were dosed with 2-PN once daily by gavage at dose levels of either 0, 1, 3, or 10 mg kg(-1) day(-1) for 28 days, prior to and during cohabitation, and through day 3 of lactation. General clinical observations were recorded daily; body weights were recorded weekly. A neurobehavioral evaluation consisting of a functional observational battery and motor activity was conducted in all parental rats (10/sex per group). Clinical pathology parameters (hematology, clinical chemistry, coagulation) were measured in parental rats. Pup weights and clinical signs were recorded at birth and on lactation day 4. Parental rats were given a gross pathological examination, organ weights were obtained, and histological examination was conducted for the control and 10 mg kg(-1) day(-1) groups. No effects were seen with regard to mortality, clinical signs, functional observational battery and motor activity, hematology, or organ weights. Females receiving 10 mg/kg and males from all dose groups showed lower body weight gains and feed efficiency. Increased albumin concentrations were seen in both sexes given 10 mg/kg. Females in the 10 mg/kg group showed degeneration of the olfactory mucosa. No effects on the numbers of pups born, number surviving to lactation day 4, pup weight, and no gross anatomical development changes were observed. Under the conditions of this study, the no-observed-effect level (NOEL) for systemic toxicity in rats was 3 mg kg(-1) day(-1), based on degeneration of olfactory mucosa in females at 10 mg kg(-1) day(-1). The NOEL for reproductive and neurobehavioral toxicity in rats and for toxicity to offspring was 10 mg kg(-1) day(-1), the highest dose level tested.

Administration, Oral↗
PubMed2002

Comparison of liver enzymes in osmerid fishes: key differences between a glycerol accumulating species, rainbow smelt (Osmerus mordax), and a species that does not accumulate glycerol, capelin (Mallotus villosus).

Activities of enzymes associated with glycerol synthesis were compared in the liver of two osmerid fishes, the smelt (Osmerus mordax), which can accumulate high (400 mM) levels of glycerol and capelin (Mallotus villosus) that does not accumulate glycerol. Animals were sampled at approximately the same time of year and temperature thus negating potential seasonal effects. These species are closely related, reducing interpretative issues involving comparison between unrelated species. We found that key enzyme activities were elevated in the smelt relative to the non-glycerol accumulating capelin, namely enzymes involved with glycolysis (phosphofructose kinase-1 and aldolase), amino acid metabolism (aspartate aminotransferase and alanine aminotransferase), gluconeogenesis (phosphoenolpyruvate carboxykinase) and glycerol synthesis (glycerol-3-phosphate dehydrogenase). The enzyme profiles strongly support the hypothesis that smelt can synthesize glycerol by utilizing glycogen and amino acids as the carbon source and that they have increased capacity for metabolic flux through loci required for synthesis of the three carbon intermediate dihydroxyacetone phosphate and subsequently glycerol synthesis.

Amino Acids↗
PubMed2001

Regulation of cutaneous malignancy by gammadelta T cells.

The localization of gammadelta T cells within epithelia suggests that these cells may contribute to the down-regulation of epithelial malignancies. We report that mice lacking gammadelta cells are highly susceptible to multiple regimens of cutaneous carcinogenesis. After exposure to carcinogens, skin cells expressed Rae-1 and H60, major histocompatibility complex-related molecules structurally resembling human MICA. Each of these is a ligand for NKG2d, a receptor expressed by cytolytic T cells and natural killer (NK) cells. In vitro, skin-associated NKG2d+ gammadelta cells killed skin carcinoma cells by a mechanism that was sensitive to blocking NKG2d engagement. Thus, local T cells may use evolutionarily conserved proteins to negatively regulate malignancy.

Amino Acid Sequence↗
PubMed2001

Interstitial MR lymphangiography for the detection of sentinel lymph nodes.

BACKGROUND AND OBJECTIVES: The challenge for implementation of sentinel lymph node biopsy is to develop a reliable minimally invasive technique that identifies all possible sentinel nodes with high temporal and spatial resolution. This study evaluated the use of a magnetic resonance imaging (MRI) contrast agent (USPIO) for preoperative sentinel node detection. METHODS: Anesthetized pigs received interstitial or intradermal injections of ultra small superparamagnetic of iron oxide (USPIO) (0.2 or 5 mg Fe) in the L/R posterior tongue and stifles (knee) respectively. MRI was done before, during injection and at 0.25, 0.5, 1, 2, 4, 6, 24, and 48 hr after which isosulfan blue sentinel node mapping was done. RESULTS: In the tongue, both doses of USPIO identified the sentinel node in the early images. No additional nodes were detected by MR at 24 or 48 hr. In the hind limb, sentinel nodes identified on the early MR images were also identified by the isosulfan blue. In both locations, the higher dose also identified secondary nodes some of which were also identified by the isosulfan blue. All sentinel nodes that were identified by USPIO on MRI were noted to be stained brown at the time of dissection. CONCLUSIONS: Interstitial MR lymphangiography is a useful technique for the detection of sentinel lymph nodes. This method provides excellent simultaneous temporal and spatial resolution, is minimally invasive, and can be performed preoperatively.

Animals↗
PubMed2001

MR imaging of murine arthritis using ultrasmall superparamagnetic iron oxide particles.

The objective of this work was to determine the ability of magnetic resonance (MR) imaging with ultrasmall superparamagnetic iron oxide (USPIO) particles to provide quantitative measures of inflammation in autoimmune arthritis. Mice were injected intravenously or intra-articularly with USPIO followed by magnetic resonance and histological assessment of the knee joint. Comparisons were made between MR microimages and histology in naïve mice and mice with collagen-induced arthritis.Following intravenous administration, accumulation of USPIO was observed in the popliteal lymph nodes, but not the joint. Administration of USPIO intra-articularly resulted in signal loss in the joint. The MR signal intensity could be quantified and correlated with iron staining in the synovial lining. A marked increase in USPIO uptake and a corresponding decrease in signal intensity were observed in arthritic, compared to naïve mice. Areas of focal signal loss corresponded to foci of iron staining by histology. These studies may provide a basis for the clinical application of USPIO in arthritis for assessing disease severity and monitoring response to therapy.

Animals↗
PubMed2001

Quality of care among elderly patients hospitalized with unstable angina.

BACKGROUND: Guidelines for the management of unstable angina have been published by the United States Agency for Health Care Policy and Research (currently known as the Agency for Healthcare Research and Quality); however, little information is available about the quality of unstable angina care, particularly among elderly patients. METHODS: We examined 1196 elderly Medicare-insured patients hospitalized with unstable angina (ruled out for acute myocardial infarction) at Connecticut hospitals between August and November 1995 to evaluate quality of care provided during hospitalization. Patients without therapeutic contraindications were evaluated for the use of 5 Agency for Health Care Policy and Research guideline-recommended measures: electrocardiographic examination within 20 minutes of admission, use of aspirin on admission, intravenous heparin on admission, achievement of therapeutic anticoagulation among patients provided heparin, and prescription of aspirin on discharge. RESULTS: Less than half (49.6%) of patients underwent electrocardiographic examination within 20 minutes of admission. After excluding patients with contraindications, aspirin was provided to 80.1% of patients and intravenous heparin to 59.2% of indicated patients, of whom only 43.3% achieved therapeutic anticoagulation. Aspirin was prescribed to 82.3% of eligible patients at discharge. Performance on the 5 quality measures varied widely among hospitals. CONCLUSIONS: Agency for Health Care Policy and Research guideline-recommended risk stratification and therapeutic interventions are underused in elderly patients hospitalized with unstable angina, with quality of care varying widely among hospitals.

Aged↗
PubMed2001

HTLV-I-associated granulomatous T-cell lymphoma in a child.

Adult T-cell leukemia/lymphoma (ATLL) is a T-cell malignancy closely associated with human T-cell lymphotropic virus-1 (HTLV-I). Because of its long latency period, ATLL occurs almost exclusively in adults. We report a case of a 13-year-old boy with an 8-year history of skin eruptions. After complete evaluation, a diagnosis of HTLV-I-associated lymphoma/leukemia was made. The T-cell lymphoma exhibited a granulomatous histomorphology. There have been very few reports of ATLL presenting in childhood and none, to our knowledge, demonstrating granulomatous histology. We conclude that ATLL may rarely present as a chronic granulomatous eruption in a child.

Adolescent↗
PubMed2000

The c-Abl tyrosine kinase contributes to the transient activation of MAP kinase in cells plated on fibronectin.

Previous work showed that integrin stimulation triggers activation of the c-Abl tyrosine kinase and its transient localization to focal adhesions. We now report that plating cells on fibronectin triggers association of Grb2 with c-Abl, suggesting possible involvement of c-Abl with integrin activation of the MAP kinase pathway. Expression of a kinase-defective c-Abl specifically inhibited the transient induction of Erk2 activity following cell adhesion. Together with the known ability of activated, oncogenic forms of c-Abl to activate Ras and the MAP kinase pathway, these data suggest that c-Abl contributes to the integrin induction of MAP kinase activity.

3T3 Cells↗
PubMed2000

Enterocyte expression of interleukin 7 induces development of gammadelta T cells and Peyer's patches.

The intestinal mucosa is suggested to support extrathymic T cell development, particularly for T cell receptor (TCR)-gammadelta intraepithelial lymphocytes (IELs). TCR-gammadelta cell development requires interleukin (IL)-7; IL-7(-/)- or IL-7 receptor(-/)- mice lack TCR-gammadelta cells. Using the intestinal fatty acid binding protein (iFABP) promoter, we reinstated expression of IL-7 to mature enterocytes of IL-7(-/)- mice (iFABP-IL7). In iFABP-IL7 mice, TCR-gammadelta IELs were restored, as were cryptopatches and Peyer's patches. TCR-gammadelta cells remained absent from all other tissues. Likewise, T cell development in thymus and B cell maturation in the bone marrow and spleen retained the IL-7(-/)- phenotype. Thus, IL-7 expression by enterocytes was sufficient for extrathymic development of TCR-gammadelta cells in situ within the intestinal epithelium and was crucial for organization of mucosal lymphoid tissue.

Animals↗
PubMed2000

Soccer ball-related retinal injuries: a report of 13 cases.

PURPOSE: To describe the clinical characteristics and management of retinal injuries caused by soccer ball impact as well as the mechanism of injury, prognostic features, risk factors, and possible prevention strategies. METHODS: Thirteen cases of soccer ball injuries from retina referral practices were retrospectively reviewed, with attention to the mechanism of associated ocular complications and the anatomic and visual outcomes. RESULTS: Soccer ball injuries occurred in both male and female patients (9 male, 4 female) with ages ranging from 8 to 21 years (median 14 years). These patients were observed from 0 to 64 months (median follow-up, 8 months). Four patients had traumatic macular holes, two eyes had retinal detachment associated with retinal dialysis, two had retinal tears associated with hemorrhage, one had a choroidal rupture, and one had only vitreous hemorrhage and Berlin's edema. Although six eyes had some degree of traumatic retinal pigment epitheliopathy, it was the primary diagnosis in only three. Visual acuity at presentation ranged from 20/20 to count fingers, with 7/13 (54%) having 20/200 or worse vision. Seven eyes underwent surgical procedures; the remainder were observed. Final visions ranged from 20/20 to count fingers, with 3/13 (23%) having 20/200 or worse vision. Six eyes (46%) improved by two or more lines by the last follow-up. CONCLUSION: Soccer ball-related ocular injuries disproportionately affect young players, are more frequent in females than previously reported, and have more severe visual consequences than previously recognized. Injury prevention strategies to minimize contact between the eye and the soccer ball may reduce the incidence and severity of eye injuries.

Adolescent↗
PubMed2000

Repairing the bond in important relationships: a dynamic for personality maturation.

OBJECTIVE: The author sought to establish a common set of interactional dynamics involved in growth-facilitating interpersonal relationships. METHOD: Empirical studies of the three most common dyadic relationships associated with personality growth were reviewed: infant-mother attachment behaviors, the psychotherapeutic alliance, and the marital relationship. RESULTS: Empirical and clinical studies support the conclusion that growth is facilitated when a strong affective bond is established with an important other and the inevitable disruptions of this bond are repaired. CONCLUSIONS: Personality maturation across the lifespan has been attributed to the internalization of admirable qualities of important others. The data surveyed suggest that the interactional dynamics associated with internalization involve establishing a strong affective bond with an important other and repairing this bond's inevitable ruptures. It is both the rupture and the repair that are crucial.

Adult↗
PubMed1999

Nonvitrectomizing vitreous surgery: a strategy to prevent postoperative nuclear sclerosis.

OBJECTIVE: The development or progression of postoperative nuclear sclerosis is the most common complication of successful vitrectomy in elderly patients. The authors treated idiopathic epimacular proliferation (EMP) with nonvitrectomizing vitreous surgery in an attempt to prevent postoperative nuclear sclerosis. DESIGN: Prospective, nonrandomized, comparative case series. PARTICIPANTS: The authors surgically removed membranes from the sensory retina in 21 eyes of 21 patients with EMP. INTERVENTION: Neither intravitreal infusion nor vitrectomy of any kind was performed during the procedure. The peeled membrane was left floating in the vitreous cavity in 11 (group 1) eyes and removed in 10 eyes (group 2). Nonoperated fellow eyes served as controls. MAIN OUTCOME MEASURES: Visual acuity, slit-lamp and/or Scheimpflug photography, and refractometry were performed pre- and postoperatively to evaluate changes in the degree of lenticular opacity. RESULTS: There was no difference in the rate of development or progression of nuclear sclerosis or the degree of myopic shift between operated and control eyes during the postoperative follow-up period (mean, 9.7 months). No serious complications were noted. There was no difference in postoperative course between patients in the two operative groups. CONCLUSIONS: Although interpretation of the results of this study is limited due to its small size and short follow-up, nonvitrectomizing vitreous surgery seems to decrease the postoperative development or progression of nuclear sclerosis in patients with idiopathic EMP.

Aged↗
PubMed1999

Medicine, economics and agenda-setting.

The filtering of potential policy issues from a large range of possibilities to a relatively small list of agenda items allows the organisation of power and influence within a policy sector to be examined. This study investigated power and influence in health policy agenda-setting in one State of Australia (Victoria) in the years 1991, 1992 and 1993. The actors seen as influential were predominantly medically trained and working in academia, health bureaucracies and public teaching hospitals. This research supports an elite model of health policy agenda-setting, in which outcomes are dependent on the structured interests within the policy field. However, while the corporate elite of the profession is influential, the frontline service providers are not, as indicated by the location of influentials in large and prestigious organisations. Politicians and professional associations and unions are less well represented, and consumer and community groups are virtually absent. In 1993 there was a sharp increase in economists being nominated as influentials, with a subsequent decrease in influentials with medical training. This relates to a (perceived or real) shift in influence from the medical profession to senior health bureaucrats. Economic concerns appear to be shaping the visible health policy agenda, through an increased number of influentials with economics training, but also through an apparent ability to shape the issues that other influentials are adding as agenda items. The corporate elite of medicine remains powerful, but their range of concerns has been effectively limited to cost containment or cost reduction, better planning and efficiency. This limiting of concerns occurs within an international policy context, where the general trends of globalisation and an emphasis on neo-liberal economics impact on the direction of health policy in individual countries.

Health Planning Councils↗
PubMed1999

Change in retinal sensitivity due to excision of choroidal neovascularization and its influence on visual acuity outcome.

PURPOSE: Excision of choroidal neovascular membranes (CNV) has been attempted as an alternative to photocoagulation for the management of subfoveal CNV. To evaluate functional results of CNV excision, we studied retinal sensitivity in the area corresponding to the CNV (CNV area). METHODS: Static microperimetry using a scanning laser ophthalmoscope was performed on 17 eyes before and after CNV excision. We studied whether CNV excision changed retinal sensitivity in the CNV area. To evaluate the relationship between retinal sensitivity and visual acuity, further testing was performed on nine patients who had subfoveal CNV from age-related macular degeneration (ARMD). RESULTS: Preoperatively, 5 of 17 eyes (29.4%) had retinal sensitivity in the CNV area. Postoperatively, 4 of 17 (23.5%) eyes had retinal sensitivity. Surgery did not significantly change retinal sensitivity in the CNV area (P>0.999). There was a significant correlation between the presence of retinal sensitivity and visual acuity. Postoperative visual acuity of eyes with retinal sensitivity in the CNV area was better than that of the eyes without sensitivity in the patients with subfoveal CNV from ARMD (P = 0.0017). CONCLUSIONS: In most cases, excision of CNV does not improve central retinal sensitivity, and patients have poor visual outcome. In some cases, however, postoperative sensitivity in the bed of CNV is preserved and visual outcome is relatively good. Better or worse preoperative retinal sensitivity does not predict better or worse visual acuity outcome, respectively.

Adult↗
PubMed1999

Food service in long day care centres--an opportunity for public health intervention.

OBJECTIVE: To determine the characteristics of long day care centre operations, food service management practices, and nutrition resources use and needs. METHOD: In October 1996, all 330 long day care centres in Western Australia were surveyed by telephone to gather information to help develop strategies for food service improvement. RESULTS: The response rate was 85%. An accreditation committee directed operations in 76% of centres. Most centres employed a cook with limited or no cooking training. Coordinators identified training needs for cooks that are specific to the National Childcare Accreditation Council's Quality Improvement and Accreditation System (QIAS) guidelines: food hygiene; nutritional and food requirements of children; menu planning; and multicultural cooking. CONCLUSIONS: National standards for the quantification of foods to meet children's nutritional requirements in long day care would allow for consistency in educating child care workers, training cooks, and establishing and assessing government regulations and the QIAS guidelines. Nine recommendations for strategies to improve food service in long day care are presented. IMPLICATIONS: There are two main messages for public health practitioners working to improve the quality of food served to children in long day care: the strong influence of the QIAS guidelines, and the need for specific nutrition recommendations.

Child↗
PubMed1998

Integrins regulate the association and phosphorylation of paxillin by c-Abl.

The c-Abl proto-oncogene is a non-receptor tyrosine kinase whose activity and localization are regulated by integrins. Cell adhesion to fibronectin triggers the transient recruitment of c-Abl from the nucleus to focal adhesions and activation of its tyrosine kinase. To investigate the integrin regulation of c-Abl, proteins that interact with c-Abl following cell adhesion were assayed. Several proteins that were phosphorylated on tyrosine were found to transiently co-precipitate with c-Abl during cell adhesion, and one was identified as the focal adhesion protein paxillin. Abl also became transiently phosphorylated in response to cell adhesion. In addition, paxillin was found to serve as substrate for the adhesion-activated c-Abl kinase. These results suggest that c-Abl may mediate effects of integrins on cell functions by phosphorylating paxillin.

Animals↗