Biomedical subjects

D Nguyen

Publications and source records attributed to D Nguyen.

154 records · Page 9Linked to original sources

PubMedDate not supplied

Overexpression of human keratin 16 produces a distinct skin phenotype in transgenic mouse skin.

Human cytokeratin 16 (K16; 48 kDa) is constitutively expressed in postmitotic keratinocytes in a variety of stratified epithelial tissues, but it is best known for the marked enhancement of its expression in stratified squamous epithelia showing hyperproliferation or abnormal differentiation. Of particular interest to us, K16 is strongly induced at the wound edge after injury to the epidermis, and its accumulation correlates spatially and temporally with the onset of reepithelialization. To examine the properties of K16 in its natural cellular context, we introduced a wild-type human K16 gene into the germ line of transgenic mice. Several transgenic lines were established and characterized. Under most conditions, the human K16 transgene is regulated tissue specifically in the skin of transgenic mice. Animals that feature low levels of transgene expression are indistinguishable from controls during the first 6-8 months of life. In contrast, transgenic animals expressing the transgene at higher levels develop skin lesions at 1 week after birth, coinciding with the emergence of fur. At a cellular level, alterations begin with the reorganization of keratin filaments and are first seen at the level of the hair follicle outer root sheath (ORS), where K16 expression is known to occur constitutively. The lesions then progressively spread to involve the proximal epidermis, with which the ORS is contiguous. Elevated transgene expression is associated with a marked thickening of these two epithelia, along with altered keratinocyte cytoarchitecture and aberrant keratinization but no keratinocyte lysis. The implications of this phenotype for epithelial differentiation, human genodermatoses, and wound healing in skin are discussed.

Animals↗

PubMedDate not supplied

Determining an individual's ideal body weight from skeletal measurements: a new method.

Determining an individual's "ideal" body weight is fundamental in nutritional therapy. A simulation of the human body to a cylindrical volumetric model permits the calculation of the ideal body weight from the measured height, interacromioclavicular distance, and humeral length. A group of 189 healthy normal volunteers were assessed. The calculated "Pitt" ideal body weight correlated closely (r = 0.88 for males, r = 0.72 for women) with values obtained from the Metropolitan tables. The technique provides an estimate of ideal body weight based upon reproducible, easily obtained measurements of fixed bony landmarks.

Adolescent↗

PubMedDate not supplied

In-line skating injuries in children: a 10-year review.

In-line skating is an increasingly popular recreational activity for both children and adults. As with any high-speed sport, traumatic injury is an associated hazard. It was the purpose of this study to focus on the injuries in children associated specifically with in-line skating with an emphasis on education and prevention. During a 9-year period, 331 injuries were identified, with 105 families completing an in-depth epidemiologic questionnaire. Sixty-one percent of the victims were boys, with an overall average age of 12 years. The upper extremity was most commonly injured (64%); the head and neck area was injured in 16% and the lower extremity in 20%. Fractures represented 38% of all injuries, with inexperience appearing to be the most common cause. An analysis of preventive strategies for childhood in-line skating was undertaken using Haddon's 10 basic preventive principles. Educational programs regarding instruction in in-line skating and the value of protective equipment need to be part of the school curriculum.

Adolescent↗

PubMedDate not supplied

Preventing sexual transmission of HIV: anti-HIV bioregulatory and homeostatic components of commercial sexual lubricants.

Certain safe over-the-counter (OTC) sexual lubricants such as Astroglide, KY Liquid, Replens, Vagisil, ViAmor, and Wet Stuff inhibit both cell-free HIV and the production of HIV by infected leukocytes in vitro even in the presence of seminal fluid. To identify which components of the lubricants were active against HIV, we tested five components (glycerin, methylparaben, propylparaben, polyquaternium-32, and propylene glycol). The paraben preservatives and propylene glycol in the lubricants did not inhibit HIV, while the common natural homeostatic metabolite, glycerin, and the thickener polyquaternium-32 did strongly inactivate infectious HIV and HIV-infected leukocytes. Activity against HIV and HIV-infected cells by glycerin was stable through 24 hours at 37 degrees C. Glycerin and polyquaternium-32 were active at minimum concentrations of approximately 2% and 0.01%, respectively--well within the highest FDA safety guidelines. Both active components disrupted infected leukocytes within 5 minutes which resulted in inhibition of infectious HIV production by infected leukocytes of greater than 25 to 100-fold. These components do not disrupt vaginal epithelial cells in vivo. These components also rapidly inactivate cell-free HIV by 10- to 30-fold. Thus, we may conclude that the active components of the OTC lubricants are glycerin and polyquaternium-32. Using these components, OTC sexual lubricants could be reformulated to optimize their anti-HIV activity. Furthermore, clinical trials of these lubricants and components seem to be indicated because of their FDA safety level, wide availability, and low cost.

Anti-Infective Agents, Local↗

PubMedDate not supplied

[Radiologic double-contrast aspects of small esophageal cancers. 38 cases].

Double contrast radiological features of thirty eight small esophageal carcinoma are described. Double contrast study is essential in the detection of small esophageal carcinomas: localized thickening of the folds (29%), localized wall stiffness (23.6%), superficial ulcers (13%), discrete superficial nodule (42%), nodularity (15.7%), and ulcerated nodule (15.7%). In our series, six carcinomas arising from reflux esophagitis have the nodular appearance. As in the majority of the cases, small esophageal carcinomas are asymptomatic, when radiologic study of esophagus is performed in patients over 40 years with heavy alcohol and tobacco use, it is imperative to use the double contrast method and to carefully search for minor mucosal abnormalities.

Adenocarcinoma↗

PubMedDate not supplied

[The value of the CO2 laser for bonding composite resins to dentin].

CO2 laser irradiation brings about structural modifications at the dentin surface. The aim of this study was to compare the tensile strength of composite resin bonded to unlased dentin and lased dentin. Dentin specimens were prepared by vestibular surface sectioning, exposing a plane dentinal surface. 40 specimens received 20 individual laser impacts with a power of 4 W and a duration of 0.1 s. 20 specimens received no laser irradiation. Half of the 60 specimens was treated with Scotchbond 2 and the other one with Scotchbond Multipurpose. Composite cylinders were polymerised for 40 seconds to these specimens. Tensile bond strengths were determined at a crosshead speed of 5 mm/min and fractured surfaces were examined at SEM after the test. Unlased dentin had significantly higher bond strength that the lased dentin.

Composite Resins↗

PubMedDate not supplied

High levels of gene transduction in human lung tumors following intralesional injection of recombinant adenovirus.

To effect gene transfer into large solid malignancies for the purpose of clinical application, new treatment strategies using intralesional administration of adenovirus were studied. Replication-deficient adenovirus Ad5LacZ, containing the Escherichia coli beta-galactosidase (beta-gal) gene (LacZ), was injected directly into 1-cm x 1-cm subcutaneous xenograph tumors of human large cell lung cancers (H460 and H1299). Each tumor received a single injection or three injections of purified virus, diluted in 200 microL of phosphate-buffered saline. The tumors were harvested 3 days after the last injection, serially sectioned, and stained with X-gal. The cells expressing beta-gal were counted by using digital image analysis and the percentage of tumor cells transduced was calculated. After a single viral injection of 1 x 10(9) PFU, 5 x 10(9) PFU, or 1 x 10(10) PFU solid tumor transduction increased significantly with dose escalation. At a dose of 1 x 10(10) PFU, transduction of the H1299 and H460 tumors was 80.2% and 46.7%, respectively. Dividing the viral dose into three injections given on alternating days had no significant effect on viral transduction. These data demonstrate that a large portion of an established human lung cancer cell line tumor undergoes gene transduction after a single intralesional injection of recombinant adenovirus.

Adenoviridae↗

PubMedDate not supplied

In vivo adenovirus-mediated p53 tumor suppressor gene therapy for colorectal cancer.

BACKGROUND: The p53 tumor suppressor gene is altered in up to 70% of colorectal cancers. MATERIALS AND METHODS: We infected the colorectal cancer cell lines SW620 and KM12L4, in which p53 is mutated, with the replication-defective adenovirus Ad5/CMV/p53 to evaluate the effects of adenovirus-mediated wild-type p53 gene transfer. Gene transduction was measured by cytochemical staining of cells infected with the Ad5/CMV/beta-gal virus and expression of the wildtype p53 protein in these cells was demonstrated by immunoblotting. RESULTS: Significant suppression of in vitro cell proliferation and induction of apoptosis (as measured by TUNEL assay labeling) were observed following Ad5/CMV/p53 infection. More importantly, similar effects were observed in vivo in an established nude mouse subcutaneous tumor model; significant suppression of tumor growth (60%-70%) and induction of apoptosis were observed following intratumoral injections of Ad5/CMV/p53. CONCLUSION: This form of therapy may provide a novel approach to colorectal cancer.

Adenoviridae↗

PubMedDate not supplied

Phosphorothioated antisense c-myc oligonucleotide inhibits the growth of human colon carcinoma cells.

BACKGROUND: The functional significance of c-myc overexpression in human colon carcinoma is unclear. MATERIALS AND METHODS: Three human colon carcinoma cell lines, LS174T, SW1116 and SW48, were treated in vitro with phosphorothioate modified antisense oligonucleotides (ASO), complementary to the c-myc translation initiation site, or two control oligonucleotides. Growth was assayed by the methyl tetrazolium (MTT) assay and colony formation. C-myc, retinoblastoma (Rb), carcinoembryonic antigen (CEA), and alkaline phosphatase (AP) expression was assessed by immunoblotting. RESULTS: The ASO specifically inhibited growth of all three human colon carcinoma cell lines. Further studies were conducted on LS174T because growth inhibition was associated with a more differentiated morphology. In LS174T cells, ASO caused a dose dependent decrease in c-myc and Rb protein expression, but an increase in CEA and AP expression. CONCLUSIONS: The growth of human colon carcinoma cells is dependent on c-myc expression, and the inhibition of c-myc expression in LS174T is associated with a more differentiated phenotype.

Alkaline Phosphatase↗

PubMedDate not supplied

The laparoscopic approach for repair of Morgagni hernias.

BACKGROUND AND OBJECTIVES: Morgagni hernias are unusual congenital diaphragmatic hernias that are generally asymptomatic and discovered incidentally. Surgical treatment is indicated once the diagnosis is made. These hernias have traditionally been repaired by the open abdominal or thoracic approaches. We report a case of Morgagni hernia repaired successfully via the laparoscopic approach. METHODS AND RESULTS: The patient was noted to have a large anteromedial diaphragmatic hernia by chest radiograph and CT imaging. He underwent laparoscopy, during which the hernia was reduced and the defect repaired with mesh placement. We used intracorporeal suture placement to anchor the mesh. The patient recovered uneventfully after a short hospitalization. CONCLUSIONS: The laparoscopic approach for repair of Morgagni hernias offers diagnostic advantages as well as the potential for reduced morbidity when compared to laparotomy. We report intracorporeal knot-tying for fixation of the mesh to be a secure and satisfactory means to achieve the laparoscopic repair.

Adult↗