PubMed Health⌕ Search

Biomedical subjects

C J Chuong

Publications and source records attributed to C J Chuong.

At least 19 recordsLinked to original sources
PubMed2000

Effects of pantothenic acid on postoperative adhesion formation in a rat uterine horn model.

This randomized blind study evaluated the effect of pantothenic acid on postoperative adhesion formation in euestrogenic and hypoestrogenic environment. We used the rat uterine horn model in a university-based laboratory setting. Thirty-six Sprague-Dawley rats were randomized into two estrogenic environments: euestrogenic and hypoestrogenic. The hypoestrogenic condition was achieved in 21 rats by either the administration of gonadotropin releasing hormone agonist or ovariectomy. The remaining 15 rats were untreated and remained in the regular estrogenic state. The left uterine horn was subjected to a lesion by serosal denudation at laparotomy. Following the uterine horn surgery, the rats within each environment were randomized into three treatment groups: saline (control), intraperitoneal pantothenic acid and intramuscular pantothenic acid. The degree of adhesions ten days following surgery was scored by an evaluated blinded to the rat's estrogenic condition and treatment. In the hypoestrogenic environment, there were no differences in the mean adhesions scores by treatment. In euestrogenic rats, the intraperitoneal pantothenic acid group had a higher mean adhesion score than intramuscular pantothenic acid, but neither treatment mean differed from that of the saline group. There was no difference in the mean adhesion scores of the saline groups by estrogenic environment. We concluded that pantothenic acid was not found to decrease adhesions formation when administered intraperitoneally or intramuscularly at these dosages. Contrary to previous reports, the hypoestrogenic condition alone was not found to be associated with decreased adhesion formation in our study.

Animals↗
PubMed1999

Effects of misoprostol on lipoprotein (a) levels of ovariectomized rats.

OBJECTIVE: To determine the effects of misoprostol on plasma lipoprotein (a) concentrations of ovariectomized rats. DESIGN: Controlled prospective study. SETTING: Animal research laboratory. ANIMAL(S): Four-month-old female Sprague-Dawley rats. INTERVENTION(S): Blood samples were obtained before and 60 days after ovariectomy, and the rats were divided into three groups. Group I (five rats) was treated with vehicle (water); groups II and III (nine and eight rats, respectively) were treated with oral misoprostol at 100 and 200 microg/kg/d, respectively, for 60 days, after which blood was drawn again. MAIN OUTCOME MEASURE(S): Serum lipoprotein (a) levels. RESULT(S): The median lipoprotein (a) level before ovariectomy was 10.8 mg/dL (range, 10.6-46.5 mg/dL). Sixty days after ovariectomy, the level increased significantly to 15.9 mg/dL (range, 10.6-36.9 mg/dL). After treatment, there was no change in lipoprotein (a) levels in the vehicle-treated group (range, 16.3-21.1 mg/dL); however, the lipoprotein (a) levels decreased significantly in the group treated with 100 microg/kg/d of misoprostol, from 15.4 mg/dL to 10.8 mg/dL, and in the group treated with 200 microg/kg/d of misoprostol, from 17.1 mg/dL to 10.6 mg/dL. CONCLUSION(S): Misoprostol caused a significant decrease in lipoprotein (a) levels.

Animals↗
PubMed1999

Effects of misoprostol on bone loss in ovariectomized rats.

This study was performed to investigate whether misoprostol (prostaglandin E1 analogue) (Cytotec, Searle, England) is effective for restoration of bone loss. Four-month-old parous female Sprague-Dawley rats (n = 30) were subjected either to bilateral ovariectomy (OVX, 24 rats) or to sham surgery (sham, 6 rats). The OVX rats were divided into four groups 60 days after the surgery. Six of them were killed, and dual-energy X-ray absorption (Norland xr-36, Norland Corporation, Fort Atkinson, WI, USA) measurements were performed, called pretreatment OVX group. The remaining groups (each had 6 rats) treated orally with 0 (control), 100, 200 micrograms/kg/day misoprostol for 60 days. All rats were killed 60 days after having treatment, and bone loss of the lumbar spine was measured by dual-energy X-ray absorption. The bone mineral density was decreased by 25.4% in control group and 23.6% in pretreatment group compared to sham group, but restored by 86% and 96% in groups treated with 100 and 200 micrograms/kg/day misoprostol, respectively. These results suggest that misoprostol restores bone loss in the lumbar spine of OVX rats in a dose-dependent manner.

Absorptiometry, Photon↗
PubMed1998

Sequelae of postpartum sterilization.

This study was designed to investigate the menstrual, psychosexual, psychological and somatic sequelae in a group of women who may be more prone to express regret following postpartum sterilization. The follow-up was conducted by questionnaire at six months and five years following the procedure. Data were available from 242 patient; 76.8% were below the age of 30. Of all patients, 21.9% expressed regrets. About one third had various menstrual disturbances. Patients rated their sex life as generally more enjoyable in many aspects. The most common psychological symptoms were irritability, nervousness and depression; while the common somatic symptoms were pelvic/abdominal pain and backache and tiredness.

Adaptation, Psychological↗
PubMed1997

An in vitro force measurement assay to study the early mechanical interaction between corneal fibroblasts and collagen matrix.

An in vitro force measurement assay has been developed to quantify the forces exerted by single corneal fibroblasts during the early interaction with a collagen matrix. Corneal fibroblasts were sparsely seeded on top of collagen matrices whose stiffness was predetermined by micromanipulation with calibrated fine glass microneedles. The forces exerted by individual cells were calculated from time-lapse videomicroscopic recordings of the 2-D elastic distortion of the matrix. In additional experiments, the degree of permanent reorganization of the collagen matrices was assessed by lysing the cells with 1% Triton X-100 solution at the end of a 2-hour incubation and recording the subsequent relaxation. The data suggest that a cell can exert comparable centripetal force during either extension of a cell process or partial retraction of an extended pseudopodia. The rates of force associated with pseudopodial extension and partial retraction were 0.180 +/- 0.091 (x 10(-8)) N/min (n = 8 experiments) and 0.213 +/- 0.063 (x 10(-8)) N/min (n = 8 experiments), respectively. Rupture of pseudopodial adhesion associated with cell locomotion causes a release of force on the matrix and a complete recoil of the pseudopodia concerned; a simultaneous release of force on the matrix was also observed at the opposite end of the cell. Lysis of cells resulted in 84 +/- 18% relaxation of the matrix, suggesting that little permanent remodeling of matrix is produced by the actions of isolated migrating cells.

Animals↗
PubMed1997

Sleep pattern changes in menstrual cycles of women with premenstrual syndrome: a preliminary study.

OBJECTIVE: The objective of this study was to investigate the sleep pattern changes across the menstrual cycle in patients with premenstrual syndrome. STUDY DESIGN: This prospective study was conducted in a university-based premenstrual syndrome clinic. The patients were selected on the basis of the comprehensive interview and visual linear analog scale. Well-matched control subjects were also selected. All the subjects underwent two consecutive sleep pattern recordings during each of three different menstrual phases in 1 month. Nine sleep parameters were recorded. RESULTS: Three patients and six controls completed the study. No cycle-related fluctuation in any parameter was noted in either the patients or the controls. No significant differences in sleep pattern were noted in the patients when compared with the controls during the same phase of the menstrual cycle. CONCLUSION: Abnormal sleep pattern in relation to premenstrual syndrome or phases of the menstrual cycle was not demonstrated in this preliminary study.

Adult↗
PubMed1997

Sterilization with fibrin sealant in a rabbit uterine horn model.

OBJECTIVE: This study investigated the effects of a fibrin sealant with or without coagulation in obliterating the tubal lumen at the uterotubal junction in rabbits. STUDY DESIGN: Twenty-three female rabbits were subjected to laparotomy and hysterotomy. They were randomly divided into four groups, and the fallopian tubes underwent different treatment: In group 1 (n = 14) both bipolar coagulation and the fibrin sealant were used. In group 2 (n = 10) only fibrin sealant without coagulation was used. In group 3 (n = 11) only coagulation was used. In group 4 (n = 10) no treatment was performed (control group). Two to three rabbits were euthanized on days 3 to 4, 7 to 11, 14 to 17, and 21 to 24 postoperatively. Both uterotubal junctions were excised, and step cross sections were obtained. The morphologic features including denuded epithelium with debris, submucosal fibrosis, hemorrhage, and fibrinoid matter in the tubal lumen and occluded lumen were observed. RESULTS: Tubal lumina were successfully occluded in 10 of 14 tubes (71.4%) in group 1. In groups 2 and 4 none of the tubes were occluded, and in group 3 only three tubes were partially occluded. The difference between group 1 and other groups was significant (p < 0.05). CONCLUSIONS: The effects of bipolar coagulation in enhancing the inflammatory reaction on the mucosa and scar formation induced by fibrin sealant at the uterotubal junction in the rabbit were demonstrated. This sterilization method with the use of fibrin sealant may be developed into an outpatient procedure in humans and may be a new method for female sterilization in the future.

Animals↗
PubMed1997

Collagen fiber architecture of a cultured dermal tissue.

Advances in tissue engineering have led to the development of artificially grown dermal tissues for use in burn and ulcer treatments. An example of such an engineered tissue is Dermagraft, which is grown using human neonatal fibroblasts on rectangular sheets of biodegradable mesh. Using small angle light scattering (SALS), we quantified the collagen fiber architecture of Dermagraft with the mesh scaffold contributions removed through the use of a structurally based optical model. Dermagraft collagen fibers were found to have a preferred direction nearly parallel to the long dimension of the kite-shaped mesh opening with small spatial variations over the mesh. This study demonstrated the utility of SALS as a rapid and inexpensive technique for the evaluation of gross collagen fiber architecture in engineered tissues.

Cells, Cultured↗
PubMed1997

A finite-element model of oxygen diffusion in the pulmonary capillaries.

We determined the overall pulmonary diffusing capacity (DL) and the diffusing capacities of the alveolar membrane (Dm) and the red blood cell (RBC) segments (De) of the diffusional pathway for O2 by using a two-dimensional finite-element model developed to represent the sheet-flow characteristics of pulmonary capillaries. An axisymmetric model was also considered to assess the effect of geometric configuration. Results showed the membrane segment contributing the major resistance, with the RBC segment resistance increasing as O2 saturation (SO2) rises during the RBC transit: RBC contributed 7% of the total resistance at the capillary inlet (SO2 = 75%) and 30% toward the capillary end (SO2 = 95%) for a 45% hematocrit (Hct). Both Dm and DL increased as the Hct increased but began approaching a plateau near an Hct of 35%, due to competition between RBCs for O2 influx. Both Dm and DL were found to be relatively insensitive (2-4%) to changes in plasma protein concentration (28-45%). Axisymmetric results showed similar trends for all Hct and protein concentrations but consistently overestimated the diffusing capacities (approximately 2.2 times), primarily because of an exaggerated air-tissue barrier surface area. The two-dimensional model correlated reasonably well with experimental data and can better represent the O2 uptake of the pulmonary capillary bed.

Blood Proteins↗
PubMed1997

Red cell distortion and conceptual basis of diffusing capacity estimates: finite element analysis.

To understand the effects of dynamic shape distortion of red blood cells (RBCs) as it develops under high-flow conditions on the standard physiological and morphometric methods of estimating pulmonary diffusing capacity, we computed the uptake of CO across a two-dimensional geometric capillary model containing a variable number of equally spaced RBCs. RBCs are circular or parachute shaped, with the same perimeter length. Total CO diffusing capacity (DLCO) and membrane diffusing capacity (DMCO) were calculated by a finite element method. DLCO calculated at two levels of alveolar PO2 were used to estimate DMCO by the Roughton-Forster (RF) technique. The same capillary model was subjected to morphometric analysis by the random linear intercept method to obtain morphometric estimates of DMCO. Results show that shape distortion of RBCs significantly reduces capillary diffusive gas uptake. Shape distortion exaggerates the conceptual errors inherent in the RF technique (J. Appl. Physiol. 79: 1039-1047, 1995); errors are exaggerated at a high capillary hematocrit. Shape distortion also introduces additional error in morphometric estimates of DMCO caused by a biased sampling distribution of random linear intercepts; errors are exaggerated at a low capillary hematocrit.

Algorithms↗
PubMed1996

Management of abnormal uterine bleeding.

Patients treated for dysfunctional uterine bleeding are separated into two groups: those with acute bleeding episodes and those with chronic repetitive bleeding problems. An acute bleeding episode is best controlled with the use of high-dose estrogen. A curettage is indicated for patients with acute bleeding resulting in hypovolemia, and a curettage or hysteroscopically directed biopsies is indicated for women with risk factors for endometrial cancer who have persistent bleeding problems. The management of anovulatory dysfunctional uterine bleeding is determined by the needs of the patient. In the adolescent medroxyprogesterone acetate is administered orally once a day for 10 days each month for > or = 3 months, and the patient is monitored closely thereafter. Oral contraceptives are used for women of reproductive age with anovulatory bleeding episodes who also require contraception. Clomiphene citrate is used for women of reproductive age with anovulatory bleeding who want to conceive. Oral medroxyprogesterone acetate is administered 10 days each month for 6 months for the treatment of anovulatory dysfunctional uterine bleeding alone in this age group. For the perimenopausal patient dysfunctional uterine bleeding may be treated by the administration of cyclic progestin or cyclic conjugated equine estrogens for 25 days with the concomitant administration of medroxyprogesterone acetate for days 18 to 25. The perimenopausal patient with dysfunctional uterine bleeding who is a nonsmoker and does not have evidence of vascular disease may also be treated with low-dose combination oral contraceptives. The long-term treatment for women with ovulatory dysfunctional uterine bleeding is the most difficult type of dysfunctional uterine bleeding to manage. The long-term therapy is directed at the reduction in menstrual blood loss. For these patients prolonged progestin use, oral contraceptives, nonsteroidal antiinflammatory drugs, antifibrinolytic agents, danazol, and as a last resort gonadotropin-releasing hormone agonists are part of the therapeutic armamentarium. A combination of two or more of these agents is often required to successfully control the abnormal bleeding. For patients who no longer desire future fertility and have associated pelvic pathologic disorders or for those who fail all medical regimens, surgical therapy may be considered. Either hysterectomy or endometrial ablation has been used. Patients with von Willebrand's disease and excessive menstrual blood loss may be misdiagnosed as having dysfunctional uterine bleeding. van Willebrand's disease is the most common bleeding disorder and is present in approximately 1% of the population. It is much more common than previously recognized. There are improved diagnostic tests to identify this disorder and, most important, there is a high-concentration desmopressin acetate nasal spray available as treatment that does not involve the risk of transmission of hepatitis and human immunodeficiency virus.

Female↗
PubMed1996

Measurement of surgically induced corneal deformations using three-dimensional confocal microscopy.

The goal of this study was to develop and apply a new set of experimental techniques for measuring the local deformations induced by partial-thickness corneal incisions in situ. Eight adult cat eyes were enucleated and cannulated, with corneal viability maintained as close to in vivo conditions as possible and intraocular pressure (IOP) carefully controlled. Experimental measurements were made pre/post radial keratotomy (RK) surgery in situ at IOPs of 15, 30, and 45 mm Hg. Incision depth and cross-sectional profiles were measured at the midpoint of selected incisions using three-dimensional (3-D) tandem scanning confocal microscopy (TSCM); central corneal curvature was estimated using a commercial corneal topographical analysis system, and corneal thickness was assessed by both 3-D TSCM and ultrasonic pachymetry. Corneas were then processed for light microscopy and incision depth was measured histologically. Finite element models were developed for comparison with the experimental measurements. There was no significant change in central corneal thickness (-5.3 +/- 3.9%, n = 8) over the course of the experiments, demonstrating that normal endothelial cell function and normal stromal hydration was maintained. The in situ TSCM incision depth measurements were significantly correlated with the histological measurements (slope = 0.95, R = 0.854, p < 0.01, n = 13 incisions). Measured incision gape at the top (anterior) of the stroma was 64.9 +/- 13.4, 87.3 +/- 12.6, and 108.7 +/- 14 microns at IOPs of 15, 30, and 45 mm Hg, respectively. The 3-D incision profiles were nonlinear in shape; comparison with the finite element models suggests that the shape of the wound profile may provide unique information regarding the shear stiffness of the cornea. Overall, the data suggest that TSCM measurements of the cross-sectional profile of the incisions immediately after RK under controlled in situ conditions provide important data regarding the mechanical behavior of the cornea after refractive surgery. These data should provide the foundation for future studies into the relationships between local tissue mechanics and corneal wound healing.

Animals↗
PubMed1996

Localization of leukemia inhibitory factor in human endometrium during the menstrual cycle.

Leukemia inhibitory factor (LIF) has been shown to be imperative for the implantation of mouse blastocysts. The objective of this study was to examine the pattern of LIF protein in the human endometrium during the menstrual cycle. A low level of LIF was detected in endometrial glands during the proliferative phase. During the luteal phase, LIF staining in the glands appeared stronger in the mid- and late luteal phase than immediately after ovulation. However, a low level of LIF was detected in the stromal cells during the early and midproliferative phase, while only a minimal level was observed during the late proliferative and luteal phases.

Adult↗
PubMed1995

Leukaemia inhibitory factor in human endometrium during the menstrual cycle: cellular origin and action on production of glandular epithelial cell prostaglandin in vitro.

Leukaemia inhibitory factor (LIF) is a pleiotrophic cytokine which plays an obligatory role in mouse implantation. To investigate its potential role in the regulation of uterine function in the human, LIF secretion by isolated human endometrial glandular epithelial and stromal cells in primary culture was determined. Endometrial cells secreted a detectable amount of LIF protein during the first 48 h of culture. In the follicular and late-luteal phases, LIF secretion by both cell types was low. At every stage of the menstrual cycle, the epithelial cells secreted significantly more LIF than did stromal cells. Glandular epithelial cells of the mid-luteal phase, at the expected time of implantation in the human, secreted significantly more LIF than at other stages of the cycle. Stromal cells showed a similar, but nonsignificant, LIF secretion pattern. It could be concluded that endometrial LIF expression was dependent on cell type and stage of the menstrual cycle, and might thus play a role in human implantation. Oestradiol-17 beta stimulated both prostaglandin (PG) F and E release by the epithelial cells in both follicular and luteal phases. PGE release during the luteal phase was greater than in the follicular phase. However, addition of recombinant human LIF did not change either PGF or PGE release in either follicular or luteal phases, in the presence or absence of oestradiol.

Adult↗
PubMed1995

Critique of conceptual basis of diffusing capacity estimates: a finite element analysis.

We present a simple geometric model of a pulmonary capillary segment containing a variable number of red blood cells. The pattern of CO transfer from alveolar air to capillary red blood cells in this model is accurately computed by a finite element method and used to explore conceptual flaws in the Roughton-Forster (RF) and morphometric methods of estimating pulmonary diffusing capacity for CO. The CO uptakes calculated by the finite element method at two alveolar O2 tensions are introduced into the RF model to determine whether the anatomically defined membrane component of diffusing capacity for CO (DmCO) and pulmonary capillary blood volume (Vc) are recovered. The same capillary model is also subjected to standard morphometric analysis. Results are compared at different levels of capillary hematocrit (Hct). The RF method accurately recovers DmCO and Vc at a low Hct but modestly overestimates DmCO and underestimates Vc at higher Hct; errors arise because conductance of the tissue-plasma membrane for CO varies with alveolar O2 tension. The morphometric method seriously overestimates DmCO because the true tissue-plasma resistance to diffusion is underestimated and the effective membrane utilized for diffusion is overestimated; these errors are accentuated by a low Hct.

Animals↗