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Biomedical subjects

C Tran

Publications and source records attributed to C Tran.

36 records · Page 2Linked to original sources
PubMed1998

Demographic risk factors for injury among Hispanic and non-Hispanic white children: an ecologic analysis.

OBJECTIVES: To determine the effects of neighborhood levels of poverty, household crowding, and acculturation on the rate of injury to Hispanic and non-Hispanic white children. SETTING: Orange County, California. METHODS: An ecologic study design was used with census block groups as the unit of analysis. Measures of neighborhood poverty, household crowding, and acculturation were specific to each ethnic group. Poisson regression was used to calculate mutually adjusted incidence rate ratios (IRRs) corresponding to a 20% difference in census variables. RESULTS: Among non-Hispanic white children, injury rates were more closely associated with neighborhood levels of household crowding (adjusted IRR 2.36, 95% confidence interval (CI) 1.22 to 4.57) than with neighborhood poverty (adjusted IRR 1.06, 95% CI 0.89 to 1.26). For Hispanic children, the strongest risk factors were the proportion of Hispanic adults who spoke only some English (compared with the proportion who spoke little or no English, adjusted IRR 1.26, 95% CI 1.04 to 1.53) and the proportion who were US residents for < 5 years (adjusted IRR 1.20, 95% CI 1.001 to 1.43). Neighborhood levels of household crowding were not related to injury among Hispanic children (adjusted IRR 0.98, 95% CI 0.89 to 1.08), but surprisingly, neighborhood poverty was associated with lower injury rates (adjusted IRR 0.89, 95% CI 0.81 to 0.97). CONCLUSIONS: Cultural and geographic transitions, as well as socioeconomic differences, appear to contribute to differences in childhood injury rates between ethnic groups.

Acculturation↗
PubMed1998

Gender differences in adverse drug reactions.

The objective of this study is to identify gender-related differences in the types of symptoms and drugs reported to cause an adverse drug reaction. Patient data from the Sunnybrook Health Science Centre ADR Clinic for the period from April 1986 to May 1996 were reviewed. Of the 2,367 patients assessed, 74.1% were female. The mean age of the patients was 43 +/- 17 years. Drug classes most frequently reported to elicit an adverse event were general antiinfectives (60.4%), nervous system agents (21.5%), and musculoskeletal agents (3.7%). Skin-related reactions accounted for 49.0% of all reported adverse drug reactions. More than one agent was reported to be responsible for the adverse drug reaction(s) in 50% of the female patients, versus 33.1% of all male patients. Of the female patients, 47.6% were referred for skin or oral challenge testing, versus 41.6% of the male patients. Of the female patients, 6.2% tested positive to the agent compared with 6.1% of all male patients. These results support previous findings that female gender is a risk factor for the development of adverse drug reactions. Further work is required to elucidate the mechanisms explaining the differences observed between male and female patients.

Administration, Oral↗
PubMed1997

Successful birth after intrafallopian transfer of microhatched embryos.

OBJECTIVE: To present a successful transfer of microhatched embryos to the fallopian tubes via microlaparoscopy. DESIGN: Case report. SETTING: Private practice affiliated with a medical university. PATIENT: A 40-year-old woman with primary infertility, mildly elevated baseline FSH levels, and a history of poor ovarian response to ovulation induction. Her husband had severe oligoospermia after vasectomy reversal. INTERVENTION(S): Late luteal leuprolide acetate to pituitary down-regulation followed by pure FSH, 300 IU, and hMG, 300 IU, daily for ovulation induction. Transvaginal oocyte retrieval, intracytoplasmic sperm injection, assisted embryo hatching, microlaparoscopic intrafallopian ET. MAIN OUTCOME MEASURE(S): Amniocentesis at the 14th week of gestation revealed a normal karyotype (46,XX), birth of a normal female infant (3700 g). RESULT(S): Establishment of a single, viable intrauterine gestation followed by a vaginal delivery at term. CONCLUSION(S): This case shows the possibility of using assisted-hatched embryos for laparoscopic intrafallopian tube transfer.

Adult↗
PubMed1997

Surveillance of colonization and infection with Staphylococcus aureus susceptible or resistant to methicillin in a community skilled-nursing facility.

BACKGROUND: Methicillin-resistant Staphylococcus aureus (MRSA) is an important nosocomial pathogen in acute care hospitals and long-term care facilities. Few studies have been reported in private skilled nursing facilities (SNFs) not experiencing outbreaks of infections caused by MRSA. METHODS: From a 149-bed SNF with no outbreaks, we report a 1-year prospective surveillance study of S. aureus colonization and infection, with focus on S. aureus phenotypes, both methicillin susceptible (MS) and methicillin resistant (MR). Nasal and stool or rectal screening cultures were done on admission, and all patients underwent screening on at least a quarterly basis for 1 year. RESULTS: Overall, 35% of patients were colonized at least once with S. aureus, (72% MS, 25% MR, and 3% mixed phenotypes), 94% of the MRSA were ciprofloxacin resistant. Nasal colonization with any S. aureus was more frequent, but 13% of patients had positive results only in rectal specimens. Twenty-one percent of the newly admitted and 15% of continuing patients acquired colonization during their stay in the SNE Colonization was transient or persistent, persisted longer in the nares compared with colonization in rectal specimens, and was more stable for methicillin-susceptible S. aureus. Nine percent of patients had development of infection with S. aureus. There was no indication that MRSA colonization led to more infections than methicillin-susceptible S. aureus. Of the 13 infected patients in whom cultures had previously been obtained, seven (54%) had been colonized by the same phenotype strains. CONCLUSIONS: In this private SNF, endemic S. aureus infections occur at a low frequency, reflecting a moderate level of colonization with S. aureus. However, a trend showing gradual increases in frequencies of colonization and infection is of concern and suggests that in this SNF, future intervention could become warranted.

Aged↗
PubMed1997

Vascular expression of E-selectin is increased in estrogen-receptor-negative breast cancer: a role for tumor-cell-secreted interleukin-1 alpha.

Angiogenesis plays an important role in breast cancer growth and metastasis. Multiple adhesion molecules have been shown to perform critical functions in the process of angiogenesis. In this study, we analyzed 15 benign and 22 malignant estrogen-receptor-negative and estrogen-receptor-positive breast specimens for the presence of the endothelial cell adhesion molecules E-selectin and P-selectin. We found that E-selectin's expression was increased in the malignant breast tumors compared with their benign counterparts (23.86% of blood vessels versus 2.47%; P = 0.0005). Furthermore, E-selectin staining was found to be significantly increased in the estrogen-receptor-negative carcinomas compared with the estrogen-receptor-positive ones (P = 0.005). In vitro findings strongly correlated with the in vivo findings and showed a higher degree of E-selectin induction in endothelial cells exposed to conditioned media from estrogen-receptor-negative breast cancer cell lines than from estrogen-receptor-positive ones. The degree of E-selectin induction correlated with the amount of interleukin-1 alpha in the tumor-conditioned media. Neutralizing antibodies to interleukin-1 alpha significantly inhibited the E-selectin expression in endothelial cells exposed to tumor-conditioned media. The results indicate that the endothelial E-selectin expression during angiogenesis is related to breast carcinoma progression in vivo and that this component of angiogenesis may be due directly to tumor-cell-secreted interleukin-1 alpha.

Breast Neoplasms↗
PubMed1996

T cell recognition and cytokine production elicited by common and type-specific glycoproteins of herpes simplex virus type 1 and type 2.

T cell recognition of common and type-specific herpes simplex virus (HSV) glycoproteins was measured in 72 subjects. T cells were stimulated with whole HSV-2 antigen and glycoproteins gB2, gD2, and gG2. T cell proliferation in response to HSV-2 antigen and gG2 was significantly higher in subjects with HSV-2 infection than in those with HSV-1 infection only; responses to gB2 and gD2 were the same. T helper (Th) type 1 and Th2 cytokine production in response to whole HSV-2 antigen, gB2, and gD2 was evaluated in 33 subjects. Interleukin (IL)-2 and interferon-gamma responses to most antigens were significantly higher among HSV-2-seropositive subjects than among seronegative subjects. IL-4 synthesis was negligible; IL-10 was produced in seronegative and seropositive persons, but HSV-2 antigen responses were significantly higher in HSV-2-seropositive persons. Naturally acquired immunity to HSV involves T cell recognition of common and type-specific glycoproteins, prominent Th1 responses, and discordant Th2 responses with little IL-4 but substantial IL-10 production.

Antigens, Viral↗
PubMed1996

[Ultrasonography of the parotid venous plane].

The venous plane of the parotid gland is a good marker of the intraparotid facial nerve that no imaging method can display precisely. In our study, we performed conventional B-mode imaging, color Doppler and power Doppler to detect the venous plane of the parotid. Some healthy patients (one hundred forty-two) without head or neck disease were examined with color Doppler and Power Doppler sonography using a 10 Mhz transducer. Sonography detected the venous plane of the parotid gland in more than two thirds of the examined patients whatever the sonographic method we used. Color Doppler and Power Doppler actually increased the sensitivity and quality of the examination.

Female↗
PubMed1996

The role of the physical and traffic environment in child pedestrian injuries.

OBJECTIVE: To identify environmental risk factors on residential streets for pediatric pedestrian injuries. METHOD: The sample consisted of 39 Latino children 0 to 14 years of age injured as pedestrians on a street in the same block as their home and 62 randomly selected neighborhood control subjects matched to the case by city, age or year of birth, ethnicity, and gender. The cases were identified from a population-based hospital and coroner's office surveillance system established in north-central Orange County, CA. Neighborhood assessments were performed from 3:45 PM to 5 PM, a fairly active time for young pedestrians. The cases were compared with the controls using conditional logistic regressions; in this study design, the odds ratios were interpreted as estimates of the incidence rate ratios. RESULTS: Children living in a multifamily residence had an incidence of injury greater than that of children living in single-family residence on a single lot (odds ratio [OR] 3.1, 95% confidence interval [CI] 1.3-7.6). The ORs in the highest category were several times those in the lowest category for both parked vehicles (OR 9.6, 95% CI 2.6-36) and total number of pedestrians observed (OR 4.7, 95% CI 1.4-16). Vehicle parking, total pedestrians, vehicular traffic volume, and speed were examined in a multivariate model. The association of vehicles parked on the street with pedestrian injury risk remained significant. Unlike the crude results, progressively greater vehicular speed was associated with a marked increase in risk. Progressively higher vehicular traffic volume was associated with a progressively lower adjusted OR. CONCLUSION: The results of this analysis would indicate that residential streets with a high proportion of multifamily residence, over 50% of the curb occupied with parked vehicles, and a large number of pedestrians observed in unenclosed areas should receive high priority for intervention programs to reduce pediatric pedestrian injuries. The analysis suggests that on these streets, measures to reduce the amount of street parking (thus increasing visibility) and reductions in vehicular speed should be considered to decrease pedestrian injuries.

Accidents, Traffic↗
PubMed1991

Dimensional changes in casting titanium removable partial denture frameworks.

The difficulties encountered in casting titanium and its alloys have until recently hindered any widespread use of titanium in restorative dentistry. Now both equipment and materials are available for the routine use of titanium in the dental laboratory. This study used one of the casting systems and examined dimensional changes that occur during the construction of a removable partial denture framework. Nineteen castings were measured for horizontal and vertical plane changes. Results show these castings to have cross arch contraction, vertical plane expansion, and near neutral anterio-posterior change. It seems that pure titanium is within the range of dimension changes generally accepted for base metal removable partial denture alloys of the nickel-chromium variety.

Dental Casting Investment↗
PubMed1990

Enhanced penetration of zona-free hamster ova by sperm prepared by Nycodenz and Percoll gradient centrifugation.

The effect of sperm penetration capacity after selection procedures using Percoll (Pharmacia AB, Uppsala, Sweden) and Nycodenz (Nycomed Diagnostics, Oslo, Norway) gradient centrifugation was compared with double-washed and swim-up in 47 subfertile men. The results of sperm motility, velocity, and amplitude lateral head displacement showed no significant improvement with the centrifugation procedures. The sperm penetration assay results obtained with double-washed and swim-up technique were poor (2.7% +/- 1.7%), however, a significant enhancement was obtained by Percoll (16.3% +/- 3.7%) and Nycodenz (15.8% +/- 3.3%) processing. Nycodenz centrifugation allowed sperm penetration of zona-free hamster ova at comparable rates to Percoll separation.

Adult↗
PubMed1989

Caffeine taste test for panic disorder: adenosine receptor supersensitivity.

The present study introduces a novel measure of adenosine receptor sensitivity that is based on the action of specific receptor blockers (e.g., caffeine) to potentiate the ability to detect threshold quinine concentrations. The test is used to compare gustatory adenosinergic responses to caffeine challenges in normal controls and patients with panic disorder or posttraumatic stress disorder (PTSD). Panic disorder patients had an exaggerated response to the caffeine challenge that was not found in controls or PTSD patients, although the latter had higher anxiety scores on psychometric tests. The results are related to a model in which A1-adenosine receptors up-regulate in an attempt to modulate hyperactive excitatory neuronal systems.

Adult↗
PubMedDate not supplied

Spectral properties of topical retinoids prevent DNA damage and apoptosis after acute UV-B exposure in hairless mice.

We showed in a recent study that topical retinyl palmitate prevented UV-B-induced DNA damage and erythema in humans. Given that retinyl palmitate is a precursor of retinoic acid, the biological form of vitamin A that acts through nuclear receptors, we wondered whether these protective effects toward UV-B exposure were either receptor dependent or linked to other properties of the retinoid molecule such as its spectral properties. We determined the epidermal retinoid profile induced by topical retinoic acid in hairless mice and analyzed its effect on markers of DNA photodamage (thymine dimers) and apoptosis following acute UV-B exposure; we compared these effects to those induced by other natural topical retinoids (retinaldehyde, retinol and retinyl palmitate) which do not directly activate the retinoid receptors. We then analyzed the direct action of these retinoids on UV-B-induced DNA damage and apoptosis in cultured A431 keratinocytes. Topical retinoic acid significantly decreased (approximately 50%) the number of apoptotic cells, as well as the formation of thymine dimers in the epidermis of mice exposed to acute UV-B. Interestingly, the other topical retinoids decreased apoptosis and DNA damage in a similar way. On the other hand, neither retinoic acid nor the other retinoids interfered with the apoptotic process in A431 keratinocytes exposed to UV-B, whereas DNA photodamage was slightly decreased. We conclude that the decrease of apoptotic cells in hairless mouse epidermis following topical retinoids and UV-B irradiation reflects a protection of the primary targets of UV-B (DNA) by a mechanism independent of the activation of retinoid nuclear receptors, rather than a direct inhibition of apoptosis.

Animals↗
PubMedDate not supplied

Cutaneous vitamins A and E in the context of ultraviolet- or chemically-induced oxidative stress.

Vitamins A and E are present in mammalian skin. Although the main circulating form of vitamin A in the blood is retinol, the epidermis stores it as retinyl esters. The epidermis can be easily loaded with high amounts of vitamin A by topical application of either retinol or retinaldehyde, two well-tolerated precursors of the biologically active retinoic acid, while topical alpha-tocopherol loads the epidermis with vitamin E. The probable physiological function of epidermal vitamin E is to contribute to the antioxidant defense of the skin, whereas that of epidermal vitamin A (retinol and retinyl esters) is not yet well understood. Besides being a precursor for retinoic acid, vitamin A also has a free radical scavenging potential. Due to their physical properties, vitamins A and E absorb ultraviolet (UV) light in the region of solar spectrum that is responsible for most of the deleterious biological effects of the sun. In the mouse, topical vitamin A has been shown to prevent the UV-induced epidermal hypovitaminosis A, while topical vitamin E prevents oxidative stress and cutaneous and systemic immunosuppression elicited by UV. Thus constitutive epidermal vitamins A and E appear complementary in preventing UV-induced deleterious cutaneous and systemic effects, and these properties can be reinforced by topical application of retinol or retinaldehyde and topical alpha-tocopherol.

Administration, Topical↗
PubMedDate not supplied

Penetration and metabolism of topical retinoids in ex vivo organ-cultured full-thickness human skin explants.

The human epidermis contains endogenous retinoids [retinol (vitamin A) and retinyl esters] and carotenoids (mostly beta-carotene). Previous studies in the mouse have shown that the enzymes involved in retinoid metabolism are present in the epidermis. In this study, we wanted to assess the skin penetration and metabolism of topical retinoids in the human. To do this, fresh surgically excised human abdominal skin was mounted on Franz perfusion cells. Topical retinoic acid, retinal, retinol and retinyl palmitate were applied at 2.5 mg/cm(2) in oil-in-water creams containing 0.05% retinoids on the donor compartment, while the receptor compartment was filled with culture medium. The skin was incubated for 24 h at 37 degrees C, then epidermal retinoid concentrations were determined by HPLC. The same experiment was performed with mouse back skin mounted on Franz cells. Finally, topical retinoids were applied on the back of hairless mice for 24 h; then the mice were sacrificed and retinoid concentrations were assayed in the epidermis. In all three models, retinol and its esters were found to be endogenous, as was the case in previous studies in the mouse in vivo. The four applied retinoids penetrated well into the epidermis. Topical retinoic acid did not increase endogenous retinoids, whereas the latter were greatly increased following topical retinal in the mouse. Retinal was also metabolized into retinoic acid, unlike topical retinol and retinyl palmitate, which only increased endogenous retinoids. Topical retinal and retinol did undergo a higher metabolism in both mouse models than in human skin. In summary, the penetration and metabolism patterns of topical retinoids were quite similar in the two mouse models used, indicating that the Franz cells appear to be a good model to predict in vivo metabolism of topical retinoids. When applying this concept to our results obtained in Franz cells with human skin, we conclude that topical retinol and retinal load human skin with both storage and functional vitamin A.

Administration, Cutaneous↗
PubMedDate not supplied

Non invasive prediction of severe fibrosis in patients with alcoholic liver disease.

OBJECTIVES: The aim of this study was to assess the diagnostic accuracy of noninvasive markers of liver fibrosis in alcoholic liver disease. PATIENTS AND METHODS: Fifty-four clinical and biochemical parameters including serum fibrosis markers (hyaluronate and transforming growth factor beta1) were analyzed in 146 consecutive heavy drinkers (106 men, 40 women; mean age 49.2 years). Following liver biopsy, fibrosis was evaluated using a semi-quantitative scoring system (no fibrosis (0) to severe fibrosis (3 + )). Multivariate analysis was performed to determine the markers that were best correlated with the fibrosis score. RESULTS: Fifty-nine patients (40.4 %) had severe fibrosis (3 +) while 87 (59.6 %) had no fibrosis or moderate fibrosis (0 to 2 +). In multivariate analysis, serum hyaluronate and the prothrombin index were the best markers for the prediction of severe fibrosis. Hyaluronate and the prothrombin index had a diagnostic accuracy of 91.1 % and 89.7 %, respectively in the whole population. Finally, a significant negative correlation was found between hyaluronate and the prothrombin index (r =- 0.86, P <0.0001). CONCLUSIONS: Using only hyaluronate and the prothrombin index, 9 out of 10 alcoholic patients can be correctly classified according to the severity of liver fibrosis.

Adult↗