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Biomedical subjects

G Pang

Publications and source records attributed to G Pang.

At least 73 records · Page 4Linked to original sources
PubMed1995

Acute on chronic bronchitis: A model of mucosal immunology.

Acute bronchitis has been studied as a model of disturbed mucosal immunoregulation. A new hypothesis relating to the pathogenesis of acute bronchitis has been developed, based on altered host response as the prime mover. Infection-prone subjects had low levels of lysozyme. Effective oral immunization, especially if early, reduced levels of bacterial colonization. Future attention focuses on intra bronchial inflammation and its link to the host-parasite relationship.

Acute Disease↗
PubMed1995

An analysis on follow-up results of photoreactive keratectomy for treatment of myopia.

A prospective study of excimer laser photorefractive keratectomy (PRK) was performed with the aim of correcting a range of myopic errors between -1.00 and -10.00 diopters on 422 myopic eyes that were followed for more than one year. At postoperative one year, 91.4% of the eyes had uncorrected visual acuity of 20/20 or better, and 97.4% were within +/- 1.00 diopter of the desired emmetropia, and the corneal haze disappeared in most of the eyes. Elevated intraocular pressures were observed in 20.4% of the eyes. The decrease of one line of the best corrected visual acuity occurred in 7.6% and of two lines in 0.5% of the eyes. We think that the excimer laser PRK is a very predictable, safe, stable, and effective method to correct myopia up to -10.00 D, and longer follow-up will be necessary.

Adult↗
PubMed1995

Excimer laser photorefractive keratectomy for myopia in China. A report of 750 eyes with a 6-month follow-up.

A total of 750 six-month follow-up records of myopia treated with excimer laser photorefractive keratectomy (PRK) were analyzed. By 6 months, in group 1 (up to -6.00D, 587 eyes), uncorrected visual acuity was improved to 20/20 or better in 86.7% of treated eyes and 95.4% fell into the range of refraction of +/- 1.00D. In group 2 (-6.25D to -11.00D, 163 eyes), 74.5% of treated eyes had uncorrected visual acuity of 20/20 or better and 89.4% of the eyes were within +/- 1.00D. The designed predictability of the two groups was the same (P > 0.1). The refractive stability from 3 to 6 months between the two groups was not statistically different, and no severe complications were observed in these two groups. The excimer laser PRK for correcting myopia up to -11.00D appears to be effective, predictable, stable and safe in this study. The ideal outcome may result from the precise ablation quality of excimer laser, its computerized surgical manipulation and an appropriate postoperative management including detection of refractive indices by corneal topography and modulation by steroid.

Adult↗
PubMed1995

[Glucocorticoid-induced ocular hypertension after photorefractive keratectomy].

1,628 myopic eyes were performed with excimer laser photorefractive keratectomy (PRK) and 1% prednisolon eyedrops was used for postoperative regime. All patients after PRK were followed 2-14 months, 9.89% had an intraocular pressure of more than 2.933 kPa (22mmHg) at first month and 15.05% at third month. Male patients showed higher response to glucocorticoid than female patients. There was no correlation between elevations of intraocular pressue and refractive powers.

Administration, Topical↗
PubMed1995

[Photorefractive keratectomy for myopia: 6 month results].

The argon fluoride excimer laser is able to ablate the superficial cornea and to correct refractive problems. Photorefractive keratectomy (PRK) was performed on 103 myopic eyes ranging from -0.75D to -6.00D. We prospectively evaluated visual and refractive results that were followed for more than 6 months. Uncorrected visual acuity of 1.0 or better was achieved in 88.35%. The difference between attempted and achieved refractive correction was within +/- 1.00D in 94.17%. 10 eyes (9.71%) had trace to mild subepithelial hare and 19 eyes (18.45%) had loss of one line of best spectacle corrected visual acuity. The excimer laser PRK appears to be a predictable and effective method to correct myopia under -6.00D.

Adult↗
PubMed1994

GM-CSF, IL-1 alpha, IL-1 beta, IL-6, IL-8, IL-10, ICAM-1 and VCAM-1 gene expression and cytokine production in human duodenal fibroblasts stimulated with lipopolysaccharide, IL-1 alpha and TNF-alpha.

The role of mucosal fibroblasts in intestinal inflammatory reactions is not known. In this study, we demonstrate that fibroblasts grown from histologically normal human duodenal biopsy tissues expressed mRNA genes for granulocyte-macrophage colony-stimulating factor (GM-CSF), IL-1 alpha, IL-1 beta, IL-6, IL-8, IL-10, intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) when stimulated with lipopolysaccharide (LPS) or IL-1 alpha. The increased mRNA expression of GM-CSF, IL-1 alpha, IL-1 beta, IL-6 and IL-8 in response to IL-1 alpha and LPS stimulation was time- and dose-dependent. In contrast, IL-10 was weakly expressed when fibroblasts were stimulated with LPS, IL-1 alpha or tumour necrosis factor-alpha (TNF-alpha), but the expression was enhanced in the presence of cycloheximide combined with optimal concentrations of LPS, IL-1 alpha or TNF-alpha, IL-1 alpha was a more potent stimulator than LPS for GM-CSF, IL-6, IL-8 and IL-10 expression, but not for IL-1 alpha and IL-1 beta. Increased GM-CSF, IL-6 and IL-8 gene expression was associated with the production of cytokine proteins in culture supernatant, but IL-1 alpha and IL-1 beta remained undetectable. Dexamethasone suppressed both gene expression and protein production of GM-CSF, IL-6 and IL-8 when fibroblasts were exposed to IL-1 alpha. TNF-alpha stimulated the release of GM-CSF, IL-6 and IL-8 and, combined with IL-1 alpha, cytokine production was enhanced synergistically. Finally, both LPS and IL-1 alpha up-regulated ICAM-1 and VCAM-1 gene expression. These findings implicate duodenal fibroblasts in the initiation and/or regulation of intestinal inflammation.

Adult↗
PubMed1994

Pulmonary immunity to Pseudomonas aeruginosa in intestinally immunized rats roles of alveolar macrophages, tumor necrosis factor alpha, and interleukin-1 alpha.

The aims of this study were to assess the role played by alveolar macrophages, tumor necrosis factor alpha (TNF-alpha), and interleukin-1 alpha (IL-1 alpha) in pulmonary immunity against Pseudomonas aeruginosa in animals that have been immunized via the gut-associated lymphoid tissue. Following intra-Peyer's patch immunization and subsequent intratracheal challenge with live bacteria, significantly enhanced bacterial clearance from the lungs correlated with an increase in bronchoalveolar neutrophils, increased recruitment and phagocytic activity of alveolar macrophages, and accelerated production of TNF-alpha in the bronchoalveolar space, while levels of IL-1 alpha remained low. Administration of recombinant TNF-alpha in physiological concentrations did not affect the proliferation of P. aeruginosa in vitro, but when given intratracheally to rats at the time of infection, recombinant TNF-alpha significantly increased bacterial clearance from the lungs. In these animals, phagocytic activity of bronchoalveolar neutrophils was enhanced, while the recruitment of alveolar macrophages and neutrophils remained unchanged. In acutely infected nonimmune animals, bronchoalveolar concentrations of soluble IL-1 alpha and TNF-alpha increased until the time of death. Levels of prostaglandin E2 and thromboxane B2 were similar in each experimental group. These results indicate that infection in immune animals enhanced both recruitment and phagocytic activity of alveolar macrophages as well as induced an accelerated production of TNF-alpha. In immune challenged animals, this cytokine enhanced the phagocytic activity of neutrophils and improved bacterial clearance from the lung. Levels of soluble IL-1 alpha and TNF-alpha in nonimmune rats increased consistently following infection until the time of death, thus implicating these cytokines in the pathogenesis of acute P. aeruginosa pneumonia.

Animals↗
PubMed1993

Morphological, phenotypic and functional characteristics of a pure population of CD56+ CD16- CD3- large granular lymphocytes generated from human duodenal mucosa.

Interleukin-2 (IL-2)-dependent large granular lymphocytes (LGL) with a distinctive surface phenotype were generated from histologically normal duodenal biopsy tissues. Immunoperoxidase staining of the mucosa with an anti-CD56 monoclonal antibody revealed LGL localized in the lamina propria rather than in the epithelium. Light and electron microscopy demonstrated azurophilic and electron-dense cytoplasmic granules. Flow cytometry analysis revealed that these cells express CD45, CD56, CD2, CD7, CD11a, CD18, CD69 and the intermediate affinity (p70) IL-2 receptor (IL-2R) but not CD57, CD16, CD3, CD4, CD5, CD8, CD45RA, CD25, or the high affinity p55 IL-2R. The LGL proliferated when cultured in the presence of human rIL-2 but not in the presence of human rIL-4. Functional studies demonstrated that the LGL had strong cytotoxicity against natural killer (NK) target cells, K562, but not NK-resistant targets such as Colo 205, Melanoma and Epstein-Barr virus (EBV)-transformed B-cell lines. The LGL expressed genes for IL-5, IL-8, granulocyte-macrophage colony-stimulating factor (GM-CSF) and tumour necrosis factor-alpha (TNF-alpha) and the corresponding cytokines were detected in culture supernatant. These results provide evidence for an important role of gut mucosal LGL in the induction and regulation of inflammation and immunity in the gut.

Adult↗
PubMed1992

1987 to 1991 cost and utilization of Class IV HIV patients.

The 1987 to 1991 direct medical costs and service utilization of Class IV Human Immunodeficiency Virus (HIV) patients cared for at a Group Health Cooperative of Puget Sound (GHC) are described and compared across four time periods: 1987-'88, 1989, 1990, and 1991. Cost and utilization information for an age- and sex-matched control group of GHC enrollees not having Class IV HIV conditions are also compared to those of the Class IV HIV group. Data are presented on pharmacy, inpatient care, outpatient visits by physician specialty, laboratory, radiology, home health/hospice and other costs. The costs of the Class IV HIV population are, on average, 20 times those of the control group. The percent distribution of the control group's costs did not experience much change from 1989 to 1991. Conversely, the Class IV HIV group experienced a shift in costs from the inpatient to outpatient setting from 1987-'88 to 1989. This shift was temporary, as the locus of care shifted back to the inpatient setting over the following 2 years. Anecdotal evidence suggests that antiretroviral treatment may have led to a period in which patients required less intensive settings to manage their illness. Inpatient costs may have increased as the initial benefit of zidovudine treatment began to wane. The Class IV HIV population had greater percent of total expenses in pharmacy, laboratory, radiology, and home health/hospice services, and lower percent of total expenses in outpatient primary and specialty care than the control group.

Adult↗
PubMed1991

Oculo-cerebro-renal syndrome (Lowe's syndrome).

Oculo-cerebro-renal syndrome (Lowe's syndrome) is characterized by mental and motor retardation, cataract, glaucoma and renal abnormalities. It is an X-linked recessive metabolic disease. Two brothers suffering from Lowe's syndrome are reported. Their mother with lenticular opacities and peculiar facial appearance is in concordance with the obligate carrier. The ocular changes and heredity are discussed.

Child, Preschool↗
PubMed1990

Dual mechanisms of inhibition of the immune response by enterocytes isolated from the rat small intestine.

Antigen presentation by enterocytes isolated from the rat small bowel was studied by using T cell proliferation, and immunoregulatory function in an antigen-driven culture system, as indicator systems. Lymph node T cells obtained from rats immunized with ovalbumin (OA) failed to divide when cultured for 4 days in the presence of freshly isolated Ia+ enterocytes and OA. However, cell division was noted when enterocytes were removed after 18 h by Percoll gradient centrifugation, followed by culture of T cells for a further 4 days in the absence of antigen. The failure to divide in the primary culture was due to the secretion by enterocytes of a dialysable non-specific inhibitor. Antigen presentation by enterocytes was specific and was inhibited by monoclonal mouse anti-rat Ia antibody, OX6. An epithelial cell line (REC-2) was established from normal rat small intestine. These cells expressed Ia molecules following incubation with Concanavalin-A stimulated spleen cell supernatant, and were capable of both presenting antigen, and inducing interleukin-2 (IL-2) production, when cultured with primed T cells. Furthermore, Ia+ REC-2 cells functioned as stimulators in a primary mixed lymphocyte reaction (MLR). Both OA-primed T cells activated by enterocytes and antigen, and allogeneic MLR-activated T cells, mediated suppression which was not specific for the initiating antigen. These experiments indicated two mechanisms mediate suppression of cell division in gut mucosa. The contribution of these mechanisms to the control of inflammation at mucosal sites requires investigation.

Animals↗
PubMed1987

Efficacy of oral immunization against non-typable Haemophilus influenzae in man.

An oral polybacterial vaccine containing 1.5 X 10(9) killed Haemophilus influenzae per tablet stimulated salivary IgA anti H. influenzae antibody compared to placebo control groups according to statistical analysis using parameter estimates for the logistic model of best fit. Significant antibody secretion could only be demonstrated when three-monthly courses were taken, and when the H. influenzae were combined in a polybacterial mix. This latter form of H. influenzae is functionally defined as adjuvenated. Increasing the immunising dose 60 fold in the absence of the non H. influenzae bacterial species did not stimulate a detectable increase in salivary antibody.

Administration, Oral↗
PubMed1987

In vivo effects of beta-endorphin on lymphocyte proliferation and interleukin 2 production.

Experiments were undertaken in rats to investigate the effects of in vivo infusion of beta-endorphin (BEP) on subsequent Con A-induced proliferation and interleukin 2 (IL-2) production by spleen cells in vitro. BEP administration induced a dose-dependent enhancement of the proliferative response to Con A. Infusion of the opiate antagonist naloxone (NAL) inhibited the Con A response and infusion of NAL prior to BEP resulted in even further inhibition. None of these treatments resulted in detectable alterations in IL-2 production after 48 h in culture. To demonstrate a direct interaction between BEP and lymphocytes, spleen cells were incubated in vitro with varying concentrations of BEP and/or NAL. Enhanced Con A-induced proliferation was observed following incubation with BEP in the range 10(-12) to 10(-9) M (levels comparable to the effective in vivo doses) and this effect was abrogated by NAL pretreatment (10(-6) M). These data indicate a role for BEP in enhancing lymphocyte reactivity which is to some extent dependent on opiate receptors on the cell surface. This report extends the evidence obtained from in vitro experiments implicating endogenous opioids in modulation of host immunity by demonstrating that these effects can be obtained in vivo.

Animals↗
PubMed1987

Development of an immunoglobulin A-specific anti-Haemophilus influenzae antibody assay for detection of antibody in human mucosal secretions.

A micro-enzyme-linked immunosorbent assay for quantitation of immunoglobulin A-specific anti-Haemophilus influenzae antibody is described and characterized. It had a sensitivity of 27 ng/ml, which is appropriate to detect antibody levels in normal saliva. Specificity for H. influenzae was achieved with the H1H2 group of antigens. Absorption studies for a range of bacteria showed little cross-reactivity, with the exception of Pseudomonas aeruginosa. Absorption studies involving various antigen preparations obtained from H. influenzae indicated that the H1H2 antigen group included significant amounts of surface antigen. An analysis of saliva from normal subjects and patients with chronic obstructive lung disease showed significant differences in levels of antibody, highlighting the potential value of the assay.

Aged↗