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Biomedical subjects

S C Huang

Publications and source records attributed to S C Huang.

At least 109 records · Page 6Linked to original sources
PubMed1999

T lymphocytes and cytokine production in ascitic fluid of ovarian malignancies.

The activation status of T lymphocytes and the presence of various cytokines in ascitic fluid were examined to test peritoneal immunity in women with ovarian malignancies. Peripheral blood and peritoneal fluid were collected from 12 patients with primary ovarian cancer with ascites and 27 normal control subjects during laparoscopic examination. Lymphocyte subpopulations and the expression of activation markers on T lymphocytes were analyzed by dual-color flow cytometry. The concentrations of various cytokines and soluble interleukin (IL)-2 receptor-alpha were measured. CD8 T lymphocytes were the main component of peritoneal lymphocytes. CD69 and HLA-DR, but not CD25, were highly expressed on peritoneal T lymphocytes compared to those in peripheral blood. In ascitic fluid of ovarian malignancies, CD4 T lymphocyte concentrations were further decreased, resulting in a decreased CD4/CD8 ratio. Decreased expression of CD69 and CD25 was also noted on T lymphocytes from ascites compared with T lymphocytes in normal peritoneal fluid. IL-1b, tumor necrosis factor-alpha, IL-6, and soluble IL-2 receptor-alpha concentrations were increased significantly in the ascitic fluid of women with ovarian cancer. The decrease in activation markers on T lymphocytes is suggestive of an immunosuppressive state, despite the presence of abundant stimulatory cytokines. The immunosuppression may be multifactorial, attributed, in part, to the increased concentrations of soluble IL-2 receptor-alpha and other inhibitors.

Ascitic Fluid↗
PubMed1999

Nuclear/cytoplasmic localization of the multiple endocrine neoplasia type 1 gene product, menin.

Although the gene responsible for multiple endocrine neoplasia, type 1 (MEN1) has been identified recently, the function of its gene product, menin, is not known. To examine menin's biological role, we created an N-terminal tagged fusion protein to follow the distribution of menin in the cell. In all cell lines tested, menin was found both in the nucleus and the cytoplasm, but its localization was dependent on the phase of the cell cycle; during a nondividing phase, menin was found in the nucleus; during and immediately after cell division, it was found in the cytoplasm. To confirm the cellular localization seen with the N-terminal tagged protein, we developed and purified peptide-specific antibodies. One of these antibodies (NCI 624), which recognizes a domain (aa 383-395) of menin, was used in immunofluorescence studies to corroborate the N-terminal tagging results. Further confirmation of menin localization was obtained in a pituitary tumor cell line derived from a familial MEN1 patient, which contained a mixed cell population with either none, or one functional copy of the MEN1 gene. Our results indicate that menin functions principally as a nuclear protein but may be found in the cytoplasm during cell division.

Amino Acid Sequence↗
PubMed1999

Early detection of unilateral occlusion of duplicated uterus with ipsilateral renal anomaly in young girls: two case reports with three-dimensional sonography.

Early detection of unilateral occlusion of duplicated uterus with ipsilateral renal anomaly is very rare and difficult. We present two cases using three-dimensional (3D) sonography as a noninvasive, comprehensive and effective method in the early detection of this syndrome in the young girls. The two young, unmarried girls had irregular abdominal discomfort and pain during the recent few years. Series traditional study showed pelvic lesions, but failed to recognized the definite cause. With 3D sonography, we demonstrated the rare congenital anatomic relationships and gave the optimal management. The girls recovered soon and had uneventful OPD follow-up. Application of 3D sonography in the suspected young girls avoids unnecessary examinations and invasive interventions, decreases the morbidity and improves their quality of life.

Abnormalities, Multiple↗
PubMed1999

The Ilizarov technique for treatment of sequelae of childhood-acquired bone and joint infection.

Bone and joint infections in childhood can result in various sequelae including deformity and limb length discrepancy (LLD). Management of these sequelae is difficult and must be individualized. In this study, we retrospectively examined the efficacy of treatment with Ilizarov techniques in 30 patients suffering from sequelae of bone and joint infections in childhood, treated from 1989 to 1994. These cases comprised 17 hip infections, two septic shoulders, and 11 cases of osteomyelitis (4 femurs, 5 tibiae, 1 humerus, and 1 forearm). All patients had some evidence of LLD. There were 13 cases of hip deformity and 10 cases of unstable hips. There were also 10 cases of angular deformity and five of nonunion of bone. The mean age at treatment was 21 years. Twenty-eight patients underwent Ilizarov lengthening procedures and 18 of them underwent deformity or instability correction simultaneously. Two patients underwent Ilizarov deformity correction only. Various techniques were used, including Schanz osteotomy plus mid-shaft femoral lengthening and distraction callotasis with and without an intramedullary nail. Postoperative complications included stiffness of joints in six patients, pin tract infection in six, fracture in five, malunion in five, nonunion in four, callus shortening in four, nerve palsy in two, and over-lengthening in one. The mean duration of follow-up was 72 months. The average length gain was 6.6 cm in shortened bones, with a mean external fixator index of 40.5 days/cm. All patients were satisfied with the functional and cosmetic results. We conclude that Ilizarov techniques are effective in treating sequelae of childhood infections of bones and joints.

Adult↗
PubMed1999

Surgical treatment of severe perthes disease: comparison of triple osteotomy and shelf augmentation.

The optimal management of the severe form of Perthes disease is controversial. This retrospective study evaluated the results of two procedures in two groups of patients with Perthes disease. The Catterall classification was adopted for grouping of patients before treatment. The Herring classification was used for comparison of the follow-up radiographs. Under the concept of surgical containment, triple innominate osteotomy was performed in 14 patients at an average age of 8 years 7 months with a mean follow-up period of 4 years 3 months. Staheli's shelf augmentation was performed in 14 patients at an average age of 10 years 2 months with a follow-up period of 3 years 8 months. Radiologically, femoral head subluxation, acetabular coverage, acetabular angle, and center-edge angle were markedly improved in both groups. In the clinical evaluation using modified Sundt's criteria, both procedures were effective. Satisfactory results were achieved in 79% of 14 patients (5 good, 6 fair, and 3 poor) in the triple osteotomy group, and 100% of 14 patients (two good, 12 fair) in the shelf augmentation group. Nevertheless, triple innominate osteotomy is technically more demanding with a longer operating time and resulted in more complications. Staheli's shelf augmentation is a simpler procedure with better coverage of the acetabulum. However, asphericity of the femoral heads was observed more frequently in this group. The Herring lateral pillar classification was better than the Catterall classification in predicting the final outcomes in this study.

Acetabulum↗
PubMed1999

Numerical simulations of human head-neck dynamics.

An efficient method for gross motion simulation of human head/neck dynamics under the action of external forcing and high acceleration environments is presented. The system is composed of a serial of linked rigid bodies simulating the skull, vertebrae and torso. These bodies are connected to each other by nonlinear springs and dampers representing the physical features of disks, ligaments, and muscles. A systematic method for handling the geometry and kinematics is used to develop the model. The developed governing equations of the multibody system are useful for the development of numerical algorithms. Results show excellent agreement between the model and the experiments. The model is expected to be useful for efficient analysis of head/neck dynamics during high acceleration environments and use with whole human body simulator. The results of several examples are also presented.

Acceleration↗
PubMed1999

Quantification of myocardial blood flow using 13N-ammonia and PET: comparison of tracer models.

UNLABELLED: Several tracer kinetic methods have been proposed for quantification of regional myocardial blood flow (MBF) with 13N-ammonia and PET. Merits and limitations specific to each approach, however, generally are not clear, because they have not been evaluated in the same experimental environment. Therefore, we compared six different commonly used methods (11 modifications) to characterize the accuracy of each approach. The methods included the two-parameter model (method 1), the modified two-parameter model (method 2), the four-parameter model (method 3), the graphical analysis (method 4), the first-pass extraction method (method 5) and the dose uptake index (DUI; method 6). METHODS: Eleven studies in four dogs, 16 studies in eight healthy human volunteers and 14 studies in seven patients were performed using 13N-ammonia and PET. MBF in dogs was varied with dipyridamole and coronary occlusions and was measured independently and simultaneously with microspheres. Volunteers and patients were studied at baseline and after dipyridamole. MBF and DUI were estimated using a time-activity curve (Qi[t]) derived from dynamic images and regions of interest (ROls) and using the six methods. DUI was defined as Qi(t = 2 min) x weight/dose. RESULTS: MBF estimated by methods 1-5 correlated well with microsphere MBF in dogs. MBF estimates by method 1 correlated well with those by methods 2, 4 and 5 and to a lesser degree with those by method 3 in both dog and human studies. DUI correlated poorly with MBF by microspheres and by methods 1-5 in both dog and human studies. MBF estimates by method 3 showed larger dispersion (SD/mean flow) and higher sensitivity to metabolites correction in arterial blood than those by methods 1, 2, 4 and 5. CONCLUSION: MBF can be measured accurately using 13N-ammonia PET and tracer kinetic methods. DUI is a poor indicator of MBF values. The results indicate that preference should be given to the two-parameter model, incorporating geometrical ROI representation (method 2) among the compartment models, and to the graphical analysis (method 4) among the noncompartmental approaches.

Adult↗
PubMed1999

The treatment of Pseudomonas keratoscleritis after pterygium excision.

PURPOSE: To assess the effect of intensive topical and intravenous antibiotics plus oral prednisolone and surgical debridement in Pseudomonas keratoscleritis after pterygium excision. METHODS: We describe three cases of P. aeruginosa-induced keratoscleritis occurring 10 days to 18 months after uncomplicated pterygium excision. Treatment included early conjunctival debridement, topical and intravenous antibiotics, and low-dosage oral prednisolone. RESULTS: All three patients responded to the combined therapy. Microorganisms were eliminated, and ulcers were healed within 8 weeks. Treatment was not extended beyond that, and infection did not recur. No evisceration was required. The patients' best corrected visual acuities are 20/200, 20/400, and 20/120, respectively. CONCLUSION: Early diagnosis and prompt, intensive medical and surgical treatment may save a patient's vision and forestall evisceration.

Administration, Oral↗
PubMed1999

Recurrent herpetic keratitis induced by laser iridectomy: case report.

The mechanism for herpetic keratitis reactivation remains unclear. When observed clinically, the reactivation may be associated with a variety of endogenous and exogenous stimuli, such as strong sunlight, fever, menstruation, and psychiatric disturbances. In experimental studies, most methods of inducing recurrence have involved some degree of corneal trauma, inflammation, neuronal stimulation, or damage to the nerves that innervate the cornea. Although corneal damage after laser iridectomy (LI) is well documented, recurrent herpetic keratitis induced by LI has never been reported. Here we present an unusual case of recurrent herpetic keratitis induced by LI. The location of the bullous keratopathy was strongly correlated to the site of laser iridectomy. Clinical findings as well as the dramatic response to antiviral treatment supported the diagnosis. Although the energy for laser iridectomy is relatively safe for most circumstances, the possibility of inducing herpetic keratitis cannot be ignored. Therefore it is important for clinicians to beware of this potential complication.

Aged↗
PubMed1999

Dynamics modeling of human temporomandibular joint during whiplash.

The objective of this study is to simulate the dynamic response of the temporomandibular joint forces within a rear-end impacted vehicle. Clinicians reports symptoms of temporomandibular joint disorders in many patients who have experienced vehicle rear-end impacts. In rear-end impact, a vehicle occupant's head is thrust rearward with respect to the vehicle in a whiplash action. During this motion, complex dynamic forces act on the jaw bone. To understand the dynamic forces acting on the jaw, we extended an existing human head/neck model by adding a movable jaw, and performed simulation of the jaw motions during rear-end impacts at 4.2, 6.4 and 9.6 m/s. Results predicted temporomandibular joint torques, relative angle between the head and jaw, jaw angular acceleration and linear acceleration of the jaw's center of mass.

Accidents, Traffic↗
PubMed1999

Tumor immunology--when a cancer cell meets the immune cells.

Tumor immunology consists of two essential concepts: immune surveillance, which specifies the host immune reactions against tumor cells, and tumor immune escape, which refers to the tumor-cell evasion process against the host immune system. Effective antitumor immunity by the host immune surveillance is supposed to be dependent on the identification of tumor antigens. In the process of malignant transformation, genetic mutations with aberrant expression of cancer-related genes and protein products are potentially immunogenic, which may serve as rejection antigens. Several scenarios are proposed to be responsible for tumor immune-escape mechanisms. The elucidation of the immune deficit against cancer progression has been a difficult task and no solitary mechanism explains the complicated cancer-host immune interactions. Cancer cells may overcome immune surveillance through a common but effective pathway, either by changing the polarity of effector cells, thus down-regulating the proliferation of tumor-specific cytotoxic T cells, or altering the effector compositions of immune cells within the tumor milieu, or both. Understanding the interaction between cancer cells and host immune cells within the tumor milieu is of importance for further clinical applications of immunotherapy in cancer treatment.

Antigens, Neoplasm↗
PubMed1999

Modeling of occupant dynamics during automobile rear-end impacts.

Procedures for studying the dynamic response of the occupant within a rear-end impacted vehicle are presented. Most of the researches in the impact analysis were performed by experimental approach and this costs a lot of time and money. Especially, the repeatability is very hard to produce in a destructive condition. Most of all, the analytic parameters can be investigated are limited by the experimental approach. By using numerical techniques, this research employs Kane's equation and Huston's method to develop a simulated system with visual graphic output to observe the rear-end impact response. According to the simulated results, at a constant seatback angle the maximum acceleration values of head and chest increased with the increasing of impact velocity. Furthermore, at a constant impact velocity the relative rotation angle of a passenger's head to chest decreased with the increasing of initial seatback angle.

Acceleration↗
PubMed1999

The major facilitator superfamily.

In 1998 we updated earlier descriptions of the largest family of secondary transport carriers found in living organisms, the major facilitator superfamily (MFS). Seventeen families of transport proteins were shown to comprise this superfamily. We here report expansion of the MFS to include 29 established families as well as five probable families. Structural, functional, and mechanistic features of the constituent permeases are described, and each newly identified family is shown to exhibit specificity for a single class of substrates. Phylogenetic analyses define the evolutionary relationships of the members of each family to each other, and multiple alignments allow definition of family-specific signature sequences as well as all well-conserved sequence motifs. The work described serves to update previous publications and allows extrapolation of structural, functional and mechanistic information obtained with any one member of the superfamily to other members with limitations determined by the degrees of sequence divergence.

Amino Acid Sequence↗
PubMed1998

Dizocilpine and reduced body temperature do not prevent methamphetamine-induced neurotoxicity in the vervet monkey: [11C]WIN 35,428 - positron emission tomography studies.

[11C]WIN 35,428 (WIN), a cocaine analog that binds to the dopamine transporter (DAT), and positron emission tomography (PET) were used to evaluate the potential neuroprotective effects of dizocilpine (MK-801) on methamphetamine (MeAmp) induced neurotoxicity in the striatal dopamine system of the vervet monkey. MK-801 (1 mg/kg, i.m.) was administered 30 min prior to a neurotoxic MeAmp dosage for this species (2 x 2 mg/kg, 4 h apart); control subjects received MeAmp. MK-801 treated subjects were anesthetized by the drug for 6-8 h; throughout that period, a 2-3 degrees C decrease in body temperature was measured. At 1-2 weeks post-MeAmp, decreases of approximately 75% in striatal WIN binding were observed for both MK-801/MeAmp and MeAmp subjects. Thus, in this non-human primate species, the combination of MK-801 pretreatment and reduced body temperature did not provide protection from the MeAmp-induced loss of DAT. Further, the absence of an elevated body temperature during the acute MeAmp exposure period indicated that hyperthermia, per se, was not a necessary concomitant of the MeAmp neurotoxicity profile as has been previously demonstrated in rodents. These results provide evidence that different regulatory factors maintain the integrity of the rodent and primate striatal dopamine systems.

Animals↗
PubMed1998

Prognostic factors of primary adenocarcinoma of the uterine cervix.

OBJECTIVE: To determine which clinicopathological factors influence the prognosis of cervical adenocarcinoma. METHODS: Three hundred and two cases of primary adenocarcinoma of the uterine cervix, treated between 1977 and 1994, were studied retrospectively. Clinical data and pathological findings with respect to primary therapy were reviewed and evaluated. RESULTS: The 5-year survival rates for stages I, II, and III/IV were 75.9, 62.9, and 25.1%, respectively. International Federation of Gynecology and Obstetrics stage (P < 0. 0001), cell type (P = 0.0176), tumor grade (P = 0.023), lymph node status (P = 0.018), and bulky tumor (P = 0.007) were found to be independent factors using the stepwise Cox proportional hazards model. Old age (P = 0.0581), presence of hypertension (P = 0.46), diabetes mellitus (P = 0.18), obesity (P = 0.15), and oral contraceptive use (P = 0.42) were not found to adversely influence survival rates for cervical adenocarcinoma after adjusting for other covariates. Adenosquamous adenocarcinoma had a better prognosis than endocervical columnar cell adenocarcinoma in stages I and II (P = 0. 0235). Also, in cervical adenocarcinoma's early stages, multivariate modeling revealed that chances of survival were significantly better for patients treated by radical surgery than for patients treated by radiation therapy (P < 0.001). CONCLUSIONS: Survival rates for cervical adenocarcinoma were significantly influenced by stage, histologic subtype, tumor grade, the presence of a positive lymph node, and tumor size. Although a randomized prospective study is needed, our data imply that radical surgery may be considered a better primary modality of treatment than radiation therapy for the early stages of cervical adenocarcinoma. Further, the presence of hypertension, diabetes mellitus, or obesity may not adversely influence survival rates.

Adenocarcinoma↗
PubMed1998

Estimation of myocardial glucose utilisation with PET using the left ventricular time-activity curve as a non-invasive input function.

The validation study is described of a new modelling method that has been developed, using tracer kinetic modelling with positron emission tomography (PET) to achieve non-invasive measurement of myocardial metabolic rate of glucose (MMRGlc). Eight data sets obtained from dynamic cardiac PET 2-[18F]fluoro-2-deoxy-D-glucose (FDG) studies on human subjects are employed, and the estimation of MMRGlc using both the new and traditional methods is compared. The results from all eight human FDG studies are consistent with those from previous computer simulations. With the new method, the estimated mean of K (a parameter directly proportional to MMRGlc) increases by about 8%, and that of k 4 (the rate constant of FDG dephosphorylation) decreases by about 48%. The approach should be more suitable for use in dynamic cardiac PET studies when non-invasive means are used to obtain the plasma time-activity curve from left-ventricle PET images.

Computational Biology↗
PubMed1998

Intraoperative crystallization on the intraocular lens surface.

PURPOSE: To report a physician survey, laboratory studies, and clinical observations of intraoperative crystallization on the surface of the intraocular lens (IOL). METHOD: We sent a survey to all ophthalmologists in the states of Wyoming, Idaho, Montana, Utah, and Colorado asking whether crystallization on the IOL surface had occurred in any of their patients and what viscoelastics, IOLs, and other solutions were used. All returned surveys were tabulated and analyzed by standard statistical means. A sample of crystallization from an IOL on a glass slide submitted by a physician was analyzed to ascertain the relative elemental composition. During in vitro laboratory studies, BSS Plus (Alcon Surgical, Fort Worth, Texas) and BSS (Alcon Surgical) were measured and analyzed for precipitation. Healon GV (Pharmacia/Upjohn, Kalamazoo, Michigan) and calcium chloride were combined in various solutions and examined for precipitate formation. Silicone IOLs and plate silicone were placed in different BSS and BSS Plus solutions with different viscoelastics and varying calcium concentrations. In seven patients, prominent crystallization on an IOL surface was examined, photographed, and followed for up to 3 years. RESULTS: Two hundred six surveyed ophthalmologists returned 181 surveys (88%) and reported 29,609 cataract surgeries, with IOL implantation with 22 eyes (0.07%) (22 patients) in which intraoperative crystallization was observed on the IOL surface during 1993. The survey indicated there was a correlation with BSS Plus (chi-square = 4.9, P = .0268) and silicone IOLs (chi-square = 6.8, P = .0093). The sample showed the cation to be calcium. CONCLUSION: Crystallization on the IOL surface during cataract surgery is a rare occurrence that may be associated with calcium as the cation related to an osmotic gradient around the IOL with increased calcium concentration. If encountered surgically, the lens should be exchanged in the operating theater after irrigating the anterior chamber with BSS and completely filling the capsular bag with a low molecular weight viscoelastic.

Aged↗