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Biomedical subjects

Q H Nguyen

Publications and source records attributed to Q H Nguyen.

14 recordsLinked to original sources
PubMed1997

Human immunodeficiency virus (HIV) type-1 GP120-specific cell-mediated cytotoxicity (CMC) and natural killer (NK) activity in HIV-infected (HIV+) subjects: enhancement with interleukin-2(IL-2), IL-12, and IL-15.

Cell-mediated cytotoxicity (CMC), as mediated by cytophilic antibody to human immunodeficiency virus (HIV) antigens, may be an important defense in HIV-infected (HIV+) patients in response to the virus. In this study the ability of interleukin (IL)-2, IL-12, and IL-15 to enhance natural killer (NK) and gp120-specific CMC of mononuclear cells (MNCs) from HIV+ children and adults was examined. NK activity against K562 cells was deficient in HIV+ patients compared to controls and could be enhanced by IL-2, IL-12, or IL-15, with the combinations of IL-2 + IL-12 and IL-12 + IL-15 producing more cytotoxicity than individual cytokines. Gp120-specific CMC was significantly higher in patients than in controls. It could be increased by IL-2, IL-12, and IL-15 and further by combining IL-2 and IL-12. When an exogenous source of antibody in the form of hyperimmune HIV-specific immunoglobulin (HIVIG) was present, the response of control MNCs was much higher than that of patients, although gp120-specific cytotoxicity of patients' MNCs was significantly enhanced (two- to threefold) by the addition of HIVIG. This increment in cytotoxicity due to HIVIG, however, could not be further augmented by cytokines in controls or patients. Our findings suggest multiple cytokine administration to boost NK cell function, together with passive immunotherapy, might offer a new therapeutic approach to benefit HIV+ patients.

Adolescent↗
PubMed1996

Neovascular glaucoma after carotid endarterectomy.

The authors examined a patient who had neovascular glaucoma (NVG) shortly after ipsilateral carotid endarterectomy and followed the patient's clinical course. The authors speculate that the sudden reperfusion after endarterectomy that occurs in patients with combined central retinal artery occlusion and carotid occlusive disease may enhance the circulation of preformed angiogenesis factors, leading to the development of neovascularization. The authors recommend frequent and careful surveillance of patients with central retinal artery occlusion associated with carotid occlusive disease if ipsilateral carotid endarterectomy is performed.

Aged↗
PubMed1996

Long-term histologic studies of the Baerveldt implant in a rabbit model.

PURPOSE: The Baerveldt glaucoma implant is an aqueous shunting device with large surface area that is installed through a single-quadrant conjunctival incision. A rabbit model of the Baerveldt implant was created to obtain serial histology and clinical information over 1 year. METHODS: Modified versions of the Baerveldt implant (110 or 160 mm2) were implanted in 18 normal New Zealand white rabbit eyes. The rabbits were examined periodically and their intraocular pressures (IOPs) recorded. They were killed at monthly intervals to obtain histology of the bleb capsules. RESULTS: Thin capsules were present at 1 month, which consisted of lamellar collagen deposition surrounded by a granulomatous reaction with multinucleate giant cells. Inflammatory cells (probably macrophages) were scattered on the inner bleb surface. The granulomatous reaction resolved after 4 months. Subsequently, capsule thickness and cellularity remained relatively stable, although the collagen stroma became less compact over time. Sixteen rabbit eyes had initial IOP reductions of > or = 3 mm Hg compared with fellow eyes, which persisted up to 4 weeks postoperatively. Seven eyes (39%) exhibited a hypertensive phase (IOP exceeded that of fellow eye by > or = 3 mm Hg) from 2 weeks to 3 months postoperatively. CONCLUSION: The Baerveldt explant is surrounded by a fibrous capsule that matures over time. The bleb histology in the rabbit model is similar to that described with the Molteno implant in primates and humans, except for the eventual development of a fibroblastic inner lining in the rabbit model. This contrasts with primate and human models, in which the inner lining remains an open mesh.

Animals↗
PubMed1995

Finasteride inhibits 5 alpha-reductase activity in human dermal fibroblasts: prediction of its therapeutic application in androgen-related skin diseases.

BACKGROUND: The potential role of finasteride in treating androgen related skin disorders was investigated. METHODS: Pooled human dermal fibroblasts were used to assess the effect of finasteride on the 5 alpha-reductase activity in skin tissue. Vmax and Km were estimated in the presence of 0, 10, and 200 nM finasteride. RESULTS: Vmax values remain constant near 1.20 pmol/mg protein/h in the presence of increasing concentrations of finasteride; however, apparent Km increases from 0.27 nM at 0 nM finasteride to 0.31 nM and 0.44 nM at 10 nM and 200 nM finasteride, respectively. This suggests that finasteride competes with testosterone and has a high affinity for same binding site of the 5 alpha-reductase enzyme. Apparent Ki was estimated at 282 nM, indicating that a high concentration of finasteride is required to significantly suppress the enzyme activity. CONCLUSIONS: This study confirms that finasteride inhibits the conversion of testosterone to dihydrotestosterone in human reticular dermal fibroblasts. Finasteride may have therapeutic potential in treating skin disorders influenced by the action of dihydrotestosterone.

Androgen Antagonists↗
PubMed1994

Decrease in skin-closing tension intraoperatively with suture tension adjustment reel, balloon expansion, and undermining.

BACKGROUND: The biomechanical and viscoelastic properties of the skin enable it to be significantly stretched within a relatively short period of time. This property, called mechanical creep, is exploited in various surgical maneuvers for intraoperative closure of large surgical defects. The recently introduced Miami Suture Tension Adjustment Reel (S.T.A.R.) device permits both the precise sutured attachment of a linear cycled load to approximate the edges of widened surgical defects, and the easy measurement of wound edge tension across the defects. OBJECTIVE: It was our purpose to compare the relative effects of linear load cycling with the S.T.A.R. device, spherical load cycling with balloon expander, and surgical undermining on the closing tension of surgical defects. METHOD: Surgical wounds were created on the flanks of six pigs and these defects were closed by various methods of repair. The combination of undermining and the S.T.A.R. device ws also evaluated. RESULTS: The average total decreases in skin closing tension were: undermining, 17.8 +/- 0.5%; balloon, 28.5 +/- 1.6%; S.T.A.R. device, 36.6 +/- 4.8%. CONCLUSION: Our data showed that all three techniques were effective in lowering the tension required to approximate surgically created defects, with the S.T.A.R. device proving to be most effective. Undermining and the S.T.A.R. device also worked synergistically to decrease skin-closing tension.

Animals↗
PubMed1994

Verruca vulgaris and radiation exposure are associated with squamous cell carcinoma of the finger.

BACKGROUND: Factors associated with the development of squamous cell carcinoma (SCC) of the finger are verruca vulgaris, radiation exposure, burns, and arsenic ingestion. OBJECTIVES: We wish to further document the relationship between human papillomavirus (HPV) and roentgen exposure to squamous cell carcinoma of the finger. METHODS: A retrospective study of 32 cases of digital squamous cell carcinoma seen at UCLA Medical Center was performed. RESULTS: Ten patients (31%) had histories of verrucae at the site of the carcinoma. Eight patients (25%) had histories of x-ray therapy to the hand. CONCLUSION: Our study further supports the association of verruca vulgaris and radiation exposure in the development of squamous cell carcinoma of the finger.

Adult↗
PubMed1994

Management of acne vulgaris.

Acne vulgaris can affect both adolescents and adults. The pathogenesis of acne is multifactorial and involves overproduction of sebum, an abnormal follicular keratinization process, proliferation of Propionibacterium acnes, and hormonal and immunologic factors. Clinical manifestations of acne range from noninflammatory comedones to inflammatory papules, pustules and cysts. Current therapy allows the physician to select a variety of topical and/or systemic antibiotics, retinoids, and hormone agents aimed at specific pathogenic factors. Most treatment regimens require several weeks of consistent use to be effective. Sound patient education, a strong therapeutic alliance and modification of lifestyle factors are powerful adjuncts to medical management.

Acne Vulgaris↗
PubMed1993

Expression of CD45 isoforms in fresh and IL-2-cultured tumor-infiltrating lymphocytes from basal cell carcinoma.

Immunohistochemistry and flow cytometry analyses were performed to characterize the specific T cell subpopulations infiltrating basal cell carcinomas (BCC) and to determine their phenotypic response to in vitro expansion with IL-2. Tumor-infiltrating lymphocytes (TIL) within BCC predominantly expressed the CD45RO (activated or "memory") phenotype (65 +/- 3%) and the percentage of TIL expressing CD45RO consistently increased when cultured in vitro with IL-2 (85 +/- 5%). In comparison, fresh normal peripheral blood lymphocytes predominantly expressed the CD45RA (naive) phenotype (79 +/- 4%), but shifted to the expression of CD45RO following in vitro expansion in IL-2 (86 +/- 6%). To determine whether IL-2 alone, in the absence of antigen or mitogen, can promote naive lymphocytes to convert from the expression of the CD45RA isoform to the CD45RO isoform, we cultured purified CD45RA+ lymphocytes in IL-2. After three weeks in culture, 90% of the lymphocytes expressed exclusively CD45RO. We conclude that tumor-infiltrating lymphocytes from BCC predominantly express CD45RO and that this expression may represent specific antigen stimulation and/or in situ activation by cytokines.

Adult↗
PubMed1993

Trabeculectomy and Molteno implantation for glaucomas associated with uveitis.

PURPOSE: This study compares the outcomes of trabeculectomy and Molteno implantation in the treatment of glaucomas associated with uveitis. METHODS: Forty-five patients with uveitis, who had undergone filtering surgery for glaucomas associated with uveitis, were reviewed retrospectively. Successful outcome was defined as final intraocular pressure (IOP) of 6 to 21 mmHg, with a minimum follow-up of 6 months without visually devastating complications or loss of light perception. RESULTS: One- and two-year life-table success rates, respectively, were 81% and 73% with trabeculectomy (16 patients); 53% and 31% with combined trabeculectomy and first-stage (reserve) Molteno implantation (19 patients); and 79% and 79% with one-stage Molteno implantation (10 patients). In 11 patients who underwent second-stage Molteno implantation after trabeculectomy failure, 1- and 2-year life-table success rates were 79% and 79%, respectively. Complications included surgically treated choroidal effusions (1/45; 2%), choroidal hemorrhages (3/45; 7%), and chronic hypotony (3/45; 7%). Follow-up in all groups ranged from 5 to 70 months (mean +/- standard deviation, 28 +/- 17 months). CONCLUSIONS: Trabeculectomy provides surprisingly good results in glaucomas associated with uveitis (modulation of wound healing with antimetabolites probably would afford an even higher success rate). However, when significant, immediate postoperative and/or moderate chronic postoperative inflammation is likely, aqueous drainage devices appear more likely to control IOP.

Adult↗
PubMed1993

Incidence and management of glaucoma in Vogt-Koyanagi-Harada syndrome.

BACKGROUND: The Vogt-Koyanagi-Harada syndrome is a bilateral panuveitis associated with neurologic and dermatologic manifestations. METHODS: The authors reviewed the charts of all patients with Vogt-Koyanagi-Harada syndrome seen at their institution over the past decade to determine the incidence of glaucoma, as well as the results of medical and surgical therapy for glaucoma, in this group of patients. FINDINGS: Of 42 patients diagnosed with Vogt-Koyanagi-Harada syndrome, evidence of glaucoma requiring either medical or surgical intervention occurred in 16 patients (38.1%). Of these, nine (56.3%) had open-angle glaucoma and seven (43.7%) had angle-closure secondary to pupillary block. In 5 (31.3%) of the 16 patients, medical therapy alone was sufficient to control intraocular pressure. Eleven patients (68.7%) required surgical intervention, consisting of laser iridotomy, surgical iridectomy, trabeculectomy with or without 5-fluorouracil, and/or Molteno implantation. CONCLUSION: The relative success of each of these procedures in this group of patients is discussed. Glaucoma is a common complication in the Vogt-Koyanagi-Harada syndrome, and one that is often difficult to control.

Adolescent↗
PubMed1992

Incidence and management of glaucoma after intravitreal silicone oil injection for complicated retinal detachments.

BACKGROUND: Intravitreal silicone oil injection used for managing complicated retinal detachments can be associated with elevated intraocular pressure (IOP). This study was undertaken to determine the incidence of glaucoma in patients who underwent silicone oil injection, as well as to evaluate the effectiveness of medical and surgical therapy in patients in whom glaucoma developed. METHODS: The postoperative courses of 50 eyes of 47 consecutive patients who underwent pars plana vitrectomy and silicone oil injection for the management of complicated retinal detachments were reviewed retrospectively. The outcomes of patients who underwent silicone oil removal and/or glaucoma surgery also were evaluated. RESULTS: The mean overall postoperative IOP before any glaucoma surgery was 16.7 +/- 9.3 mmHg (range, 0 to 45 mmHg), with a mean follow-up of 16.6 +/- 12.1 months (range, 2 to 51 months). Twenty-four (48%) eyes had postoperative IOPs of at least 25 mmHg and IOP elevations of at least 10 mmHg above the preoperative levels. Twenty-one (42%) eyes underwent complete removal of silicone oil and/or glaucoma surgery to effect IOP control. The IOPs were controlled to 21 mmHg or less (but > 5 mmHg) in 8 of 14 eyes that underwent removal of silicone oil alone, in 3 of 5 eyes that underwent Molteno implantation, and in 1 eye that underwent Nd:YAG transscleral cyclophotocoagulation, but not in 1 eye that underwent a modified Schocket procedure (mean follow-up, 13.5 +/- 11.0 months; range, 0.2 to 33 months). CONCLUSION: Intraocular pressure elevation is a common occurrence after intravitreal silicone oil injection. The underlying mechanism may often be multifactorial in nature. Patients in whom uncontrolled IOP develops may benefit from aggressive medical and/or surgical treatment with silicone oil removal, glaucoma implants, or cyclodestructive procedures.

Adolescent↗
PubMed1992

Estrogen receptors and the response to sex hormones in angiolymphoid hyperplasia with eosinophilia.

BACKGROUND: Angiolymphoid hyperplasia (ALH) with eosinophilia is a benign rare tumor, characterized by marked proliferation of endothelial cells. The tumors are associated with extensive infiltrate of lymphocytes, histiocytes, and eosinophils, and occur on the head and neck of young adults. A variety of treatments have been attempted with frequent recurrences. We report two cases of ALH with eosinophilia that seemed to be dependent on sex hormones. OBSERVATION: The first case is a patient with ALH that resolved after stopping treatment with birth control pills. Biopsy specimens of the tumor demonstrated increased level of estrogen and progesterone receptors compared with her normal skin. The second case is a patient with a previous lesion of ALH with eosinophilia, who during pregnancy had new lesions develop and whose primary lesion increased in size. All lesions decreased to half their original sizes after pregnancy. CONCLUSION: Both of these cases suggest a role for hyperestrogen states with the presence of hormonal receptors. The response to sex hormones could contribute to the pathogenesis of the disease and may offer future alternative treatment modalities.

Adult↗
PubMed1989

Cadmium uptake kinetics in human erythrocytes.

Cross-membrane transport of cadmium in human erythrocytes was studied using 109Cd+(+) and liquid scintillation counting. Uptake rates were determined by depletion of radioactivity in the incubation medium and the amount of hemolyzate radioactivity taken up by the erythrocytes. Both saturable and nonsaturable components for cadmium transport were observed. The mean maximum uptake rate (Jmax) of the saturable component was 4.9 X 10(-6) mol/L/h. The transport constant (Kt) was estimated at 6.9 X 10(-5) mol/L. The diffusion constant (Kd) of the non-saturable component was 1.4 X 10(-2)/h. Both Jmax and Kt of cadmium generally decreased when Zn+(+) was present, with a biphasic response in the presence of Cu+(+). Kd of cadmium increased as Zn+(+) or Cu+(+) levels were increased. It is suggested that cadmium may penetrate human red cells via cation transport sites owing to its behavior as an analog of one or more nutrient species.

Biological Transport, Active↗