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Biomedical subjects

S S Chen

Publications and source records attributed to S S Chen.

At least 55 records · Page 3Linked to original sources
PubMed2000

Imaging of invasiveness of pituitary adenomas.

The purpose of our study was to examine the tumor size, imaging invasiveness of the pituitary macroadenomas (PMA) and to evaluate the directions of PMA spread. One hundred and thirty-five patients with PMA were examined with MRI and/or CT for pre-operative evaluation. We retrospectively reviewed the CT and MRI to identify tumor size, extension and to evaluate the directions of tumor spread. One hundred and seventeen patients (87%) had suprasellar extension with compression of optic apparatuses, twelve patients (9%) had extension of tumor upward to hypothalamus and third ventricle. Infrasellar extension via the floor of the sella and sphenoid sinus was found in thirty-eight patients (28%), and further downward extension to ethmoid sinus, nasopharynx and/or skull base was depicted in five patients (4%). Twenty-two patients (16%) had lateral invasion to the cavernous sinus and associated cranial nerves. Temporal and frontal extensions were depicted in seven patients (5%) and six patients (4%), respectively. Five patients (4%) had posterior subtentorial extension to posterior fossa. Histologically, only two patients showed microscopic invasive features. There was no correlation between histologic features and imaging invasiveness. The PMA had the potential of multi-directional extension. This experience indicated any type of pituitary adenoma could invade surrounding structures. Suprasellar invasion was the most common direction of pituitary adenoma spread, followed by infrasellar, lateral, anterior and posterior routes.

Adenoma↗
PubMed2000

Endovascular embolization of intractable epistaxis.

BACKGROUND: We undertook this study to define the role of angiography and endovascular embolization in the treatment of patients with intractable epistaxis. METHODS: A series of 19 patients with massive intractable epistaxis, all treated with endovascular embolization were reviewed. There were 15 males and four females ranging in age from 18 to 70 years, with a mean age of 38 years. The predisposing factors of intractable epistaxis were head and neck tumors (n = 11), idiopathic symptoms (n = 3), surgical complications (n = 2), arteriovenous malformation of the face (n = 1), thrombocytopenia (n = 1) and trauma (n = 1). Polyvinyl alcohol (PVA) particles and gelfoam plugs were used as embolic agents in 11 patients for devascularization; detachable balloons with N-butyl-2-cyanoacrylate (NBCA) were used in four patients for vascular occlusion; NBCA and/or coils were used in four patients in the carotid and subclavian arteries for obliteration of pseudoaneurysms. RESULTS: Complete cessation of epistaxis was achieved in all 19 patients immediately after embolization. Seven patients had also undergone surgical tumor removal at two to five days after embolization. Two patients experienced mild to moderate facial pain on the first day after the procedure, but the symptoms later subsided. No significant complication or recurrence was observed in 18 patients. One patient with advanced hypopharyngeal carcinoma died two weeks after embolization due to another episode of massive epistaxis. Clinical follow-up for these patients was 15 days to eight years, with a mean of 41 months. CONCLUSIONS: Therapeutic endovascular embolization of intractable epistaxis is both efficient and safe. It should be considered as the primary treatment modality in intractable epistaxis.

Adolescent↗
PubMed2000

Strength and functional performance of patients with limb-girdle muscular dystrophy.

This study was design to reach a better understanding of muscle strength, motor function and activity of daily living in patients of limb-girdle muscular dystrophy. Forty-eight patients diagnosed as cases of limb-girdle muscular dystrophy were included in this study. Manual muscle testing was used to evaluate muscle strength. The Brooke and Vignos scales were used to grade upper and lower extremities function, respectively, and the ability of daily living activity was measured by Barthel index. Our patients showed progressive symmetrical limb-girdle muscular weakness. Upon regression analysis we found that mean muscle strength was inversely related to disease duration (years) as follows: mean muscle strength = 0.6052 + (0.6309/disease duration). According to the Brooke functional scale, 89.6% of our patients were graded as 1-3 and 10.4% were graded as 5. On the Vignos functional scale, 79.1% of patients fell into the grades 1-5, one person (2.1%) in grade 6 and 18.8% in grade 9 category. The average Barthel index was 85.3 +/- 20.7. Mean muscle strength was significantly correlated with the average Barthel, Vignos and Brooke functional scales. Our study could offer the strength and functional performance of limb-girdle muscular dystrophy on natural history. The muscle strength declined in Taiwanese patients of limb-girdle muscular dystrophy in a typical pattern. Regression analysis showed that the strength was inversely related to disease duration. These findings demonstrate that most of our patients suffered from mild or moderate physical disability.

Adolescent↗
PubMed2000

Far lateral lumbar disc herniation.

BACKGROUND: Far lateral lumbar disc herniation is an uncommon condition that may compress the nerve root outside the vertebral canal and in its extraforaminal course. The traditional midline interlaminar approach for the exploration of far lateral lumbar disc herniation is often difficult because the intervertebral articulation obviates a direct view of the course of the extraspinal nerve. In this report, we present two surgical approaches for the treatment of far lateral lumbar disc herniation: the paramedian muscle-splitting microtechnique and the enlarged midline approach. METHODS: Eight patients with far lateral lumbar disc herniation were found among 160 lumbar disc operations in 160 patients. According to computed tomography results, we divided patients with far lateral lumbar disc herniations into two groups; the extraforaminal and foraminal groups. Clinical presentation, imaging studies and surgical approach were thoroughly reviewed. RESULTS: Three patients in the extraforaminal group underwent the paramedian muscle-splitting microtechnique. Two patients in the foraminal group underwent the enlarged midline approach. The other three were operated on before the introduction of the paramedian muscle-splitting microtechnique and the enlarged midline approach. One of these patients who underwent the traditional interlaminar approach with resection of the lateral portion of facet joint, received additional instrumentation and fusion for the prevention of further instability. All had good results and no further surgical treatment was necessary. CONCLUSIONS: The incidence of far lateral lumbar disc herniation was 5% of all surgically treated disc herniations at our institution. For the extraforaminal group, the paramedian muscle-splitting microtechnique is the surgical route of choice. For the foraminal group, the enlarged midline approach is better than the traditional, interlaminar approach in saving the facet joint and preventing postoperative instability.

Adult↗
PubMed2000

Cavernous sinus gas.

Gas within the cavernous sinus is an unusual finding. We report three patients who demonstrated gas in the cavernous sinus on computerized tomography (CT). The clinical information of these patients was reviewed for the possible source of the gas and the symptoms induced by the gas. Cavernous sinus gas was seen in two patients with sphenoid sinus fracture and in one patient after intravenous fluid infusion. None of the patients had symptoms referable to the cavernous sinus gas, but one patient had a grave prognosis due to trauma. Identification of cavernous sinus gas on CT and correlation with the clinical information is mandatory for further management.

Adult↗
PubMed2000

Five-year follow-up of patients with recurrent postmenopausal bleeding.

BACKGROUND: The most common symptom of endometrial cancer is postmenopausal bleeding. For women who present with postmenopausal bleeding and a benign tissue diagnosis, recurrent bleeding is a worrisome problem. We evaluated such patients to search for a model of good management. METHODS: We studied women aged 50 years or over who presented with postmenopausal bleeding and underwent either dilatation and curettage (D & C) or endometrial biopsy from 1990 to 1991 at Long Island Jewish Medical Center, New Hyde Park, NY, USA. The selected patients were monitored for 5 years, until 1996. For those who had an initial benign tissue diagnosis and presented with recurrent postmenopausal bleeding in the following 5 years, we studied the differences in histologic diagnoses. RESULTS: Seventy-seven patients had an initial benign tissue diagnosis of postmenopausal bleeding followed by recurrent bleeding. After repeat D & C or endometrial biopsy (2-6 times), 16 patients (20.8%) had endometrial cancer or endometrial complex hyperplasia. Of the 12 patients who had two or more benign tissue diagnoses, seven (58.3%) had tumors found in subsequent surgery. The diagnoses included endometrial cancer, ovarian cancer, cervical cancer and benign tumor. Postmenopausal women aged 65 years or over had a much greater chance (13/29, 44.8%) of having endometrial cancer or complex hyperplasia than women aged below 65 years (6/48, 12.5%) who presented with recurrent postmenopausal bleeding and had an initial benign tissue diagnosis (c2 = 7.893, p = 0.0050). CONCLUSIONS: Although the initial tissue diagnosis might be benign, the possibility of endometrial cancer or complex hyperplasia cannot be ruled out for women with recurrent postmenopausal bleeding. Diagnostic D & C or endometrial biopsy combined with other tools (vaginal ultrasound, hysteroscopy, transvaginal sonohysterography) are more reliable for evaluating women with recurrent postmenopausal bleeding than D & C or endometrial biopsy only. If these diagnostic results are negative, a total hysterectomy with bilateral salpingo-oophorectomy should be considered to reduce the risk of endometrial cancer in women who present with recurrent bleeding.

Age Factors↗
PubMed2000

Aberrant cervical carotid artery.

Aberrant cervical carotid artery is an uncommon anomaly. Because this anomaly can lie in close proximity to the midline of the posterior part of the pharynx, it poses a significant risk during both major pharyngeal tumor resection and less extensive procedures such as tonsillectomy, adenoidectomy and palatopharyngoplasty. Five cases of aberrant cervical carotid artery were encountered and diagnosed using computerized tomography. In all five cases, the anomalous finding did not correlate with the presenting symptoms. Computerized tomographic images of these cases are provided. A review of the literature and the embryology of the aberrant carotid artery are presented. Awareness of the anomaly by radiologists and surgeons is essential to avoid accidental injury to the vessel during surgery.

Adult↗
PubMed2000

The strength and functional performance in patients with facioscapulohumeral muscular dystrophy.

Facioscapulohumeral muscular dystrophy (FSHD) is a slowly progressive myopathy with autosomal dominant inheritance remarkable for its early involvement of facial musculature. The purpose of our study was to assess the rate of strength deterioration, functional condition and performance of activity of daily living of patients with FSHD in Taiwan. Twenty patients diagnosed with FSHD were included in this study. Manual muscle testing (MMT) was used to evaluate muscle strength. The Brooke and Vignos scales were used to assess upper and lower extremity function respectively, and the capability of the activity of daily living was measured by Barthel index. The result of the strength testing was characterized by the presence of a progressive asymmetrical muscular weakness in patients with FSHD. The mean muscular strength of the right extremity was weaker than its left counterparts (p < 0.05) and the shoulder muscle group was the weakest. According to the Brooke functional scale, 20% of our patients were graded as 1, 30% as grade 2, and 50% as grade 3. On the Vignos functional scale, 50% of patients fell into grade 1, 10% in grade 2, and 40% in grades 3-5. Vignos scale was significantly correlated with mean muscle strength (p < 0.05). The average value of Barthel index was 97.8 +/- 4.7. The muscle strength decline in this Taiwanese of FSHD population was more severe in shoulder girdle area. The mean muscle strength of the right extremity was weaker than the left. Most of our patients suffered from mild or moderate physical disability. Finding of these Taiwanese FSHD population is similar to those reported elsewhere in the world.

Activities of Daily Living↗
PubMed2000

Double-balloon technique for embolization of carotid cavernous fistulas.

Embolization of a carotid cavernous fistula (CCF) by means of a detachable balloon is an established method for treating CCFs while preserving a patent parent internal carotid artery (ICA). However, failure to embolize the CCF may occur on a few occasions, such as when the balloon cannot pass through the fistula into the cavernous sinus by blood flow, or when the inflated balloon in the cavernous sinus retracts to the carotid artery. Under these circumstances, the ICA may have to be sacrificed in order to treat the CCF. Herein we describe a double-balloon technique for embolization of a CCF. By applying this technique, we successfully treated nine of 11 CCFs, without compromise of the parent ICA when the conventional one-balloon technique failed.

Balloon Occlusion↗
PubMed2000

Fat in the cerebral falx.

BACKGROUND: Fat within the cerebral falx is commonly encountered in our daily practice but has never been characterized and reported. The purpose of this study was to determine the incidence of fat within the cerebral falx and to identify its clinical features. METHODS: The cerebral falx was prospectively imaged in 1,570 consecutive brain computed tomographic scans and its features characterized. Cerebral magnetic resonance imaging was done in some patients. RESULTS: Of the 1,570 cases studied, 115 revealed a small amount of fat in the cerebral falx. This fat had a purely negative Hounsfield value. It produced a high signal on both T1- and T2-weighted magnetic resonance images. There was no calcified component. The fat was seen most commonly in aged patients. No related symptoms were noted. CONCLUSIONS: Among the patients studied, fat in the cerebral falx had an incidence of 7.3%. It is an incidental finding in adults and requires no further evaluation or treatment.

Adolescent↗
PubMed2000

Computed tomography and magnetic resonance imaging characteristics of giant pituitary adenomas.

PURPOSE: The purpose of this study was to characterize the computed tomography (CT) and magnetic resonance (MR) imaging features of giant pituitary adenoma (GPA) and to demonstrate the pathways of the spread of GPA. METHODS: CT and/or MR imaging scans of 356 patients evaluated preoperatively for single pituitary tumor were reviewed. Fourteen tumors (4%) fulfilled the radiologic criteria for GPA. There were 10 male and four female patients, ranging in age from 22 to 71 years (mean, 52 yr). We retrospectively reviewed the CT and MR imaging scans of these patients to characterize tumor appearances and identify the pathways of tumor extension. RESULTS: Thirteen tumors (93%) extended upward to the suprasellar cistern, and/or hypothalamus and third ventricle. Infrasellar extension through the sellar floor and sphenoid sinus to the skull base, or to the ethmoid sinus or the nasopharynx, was identified in seven patients (50%). Eight patients (57%) had lateral invasion to the cavernous sinus. Temporal and frontal extension was apparent in seven patients (50%) and six patients (43%), respectively. Five patients (36%) had posterior subtentorial extension to the posterior fossa. Histologically, only two GPAs showed invasive features. There was no correlation among histologic features, pituitary hormone concentrations, and evidence of tumor aggressiveness on CT and MRI scans. CONCLUSIONS: GPA has the potential for widespread, multi-directional extension. Our results indicate that any type of pituitary adenoma, regardless of its endocrinologic activity, may invade surrounding structures. Suprasellar invasion is the most common pathway of tumor spread, followed by infrasellar, lateral, anterior, and posterior routes.

Adenoma↗
PubMed2000

Knee isokinetic strength and body fat analysis in university students.

Many factors such as anthropometric variables influence strength performance. This study is to determine the relationship between knee isokinetic strength and body composition, and to compare the gender differences. Test-retest reliability had been performed within one week for all measurement methods before the formal study. Fifty-eight 20-25 year-old university students, 32 females and 26 males, participated in this study. Isokinetic strength of the knee flexion and extension was measured at two angular velocities of 60 degrees/sec and 120 degrees/sec. Body composition was measured by bioelectrical impedance analysis (BIA) and skinfold caliper. The others variables including height, body weight, body mass index (BMI), and waist to hip ratio were measured or calculated. The results showed that the intra-class correlation coefficients for isokinetic knee strength were between 0.83 and 0.93, and body composition and anthropometric variables were between 0.83 and 0.98. Isokinetic knee strength was significantly correlated with body height, body weight, BMI, waist and hip ratio and percent of body fat estimated by skinfold caliper (r = -0.56 to 0.64). The correlation between isokinetic strength with percent of body fat estimated by BIA (r = -0.60 to -0.74; p < 0.001) and with fat free mass (r = 0.64 to 0.78; p < 0.001) was even higher. Although male subjects had significantly greater mean values in body height, body weight, waist to hip ratio and isokinetic strength than female subjects, the MANCOVA showed that the effect of gender on knee isokinetic strength would be eliminated when the covariant variable, the percent of body fat measured by BIA and BMI was controlled in the analysis model. In conclusion, knee isokinetic strength was significantly negatively correlated with proportion of fat and positively correlated with fat free mass. The magnitude of strength difference between males and females could be explained by differences in body fat proportion and BMI in this study. Therapist would take the body fat composition, fat free mass, and BMI into consideration in knee muscle strength measurement. Less body fat and higher BMI will contain more fat free mass that produces more muscle strength.

Adipose Tissue↗
PubMed2000

[Expression of VEGF on rabbit skin fibroblasts using retroviral vector].

A replication-deficient recombinant retrovirus containing the cDNA coding for human vascular endothelial growth factor (VEGF) was generated, and then infected rabbit primary skin fibroblasts. After selection with G418, the transduced colonies have the ability of producing VEGF. The integration and expression of VEGF in transduced cells were confirmed by Southern blot, PCR, Northern blot and RT-PCR assay. The VEGF secreted by transduced cells has strong bioactivity when assayed by endothelial proliferation and Miles vascular permeability assay. Thus, this study pave the way for future study of biological and physiological effect of VEGF in vivo.

Adenoviridae↗
PubMed2000

[A new generation of pulmonary function measuring system].

A system for measuring the pulmonary function was reported. The System consists of Fleisch flow transducer, a pressure transducer an amplifier, A/D converter, and a 486 computer. It can measure the indices of respiratory function under tidal breathing, the indices of tidal breathing flow volume loop and the dynamic indices of passive respiration.

Humans↗
PubMed1999

Conferral of an antiviral state to CD4+ cells by a zipper motif envelope mutant of the human immunodeficiency virus type 1 transmembrane protein gp41.

We showed in a transient coexpression study that a single proline substitution for any of the five conserved leucine or isoleucine residues located in the envelope (Env) transmembrane protein gp41 zipper motif of the human immunodeficiency virus type 1 dominantly interferes with wild-type Env-mediated viral infectivity. In the present study, we intended to explore the feasibility of developing a genetic anti-HIV strategy targeting the zipper motif. Stable HeLa-CD4-LTR-beta-gal clones that harbored silent copies of Tat-regulated expression cassettes encoding the zipper motif Env mutants were first generated. Expression of any of the five Env mutants in transfectants interfered with exogenously expressed homologous HXB2 Env-mediated cytopathic effects. Mutant transfectants 566, 573, and 580 were further examined. Viral transmission mediated by the laboratory-adapted T cell-tropic HXB2 and NL4-3 viruses was greatly reduced in these transfectants compared with that observed in the env-defective control deltaKS and wt env transfectants. Moreover, viral replication mediated by the NL4-3 virus and a macrophage-tropic ADA-GG virus was delayed or reduced in human T cells harboring the mutant 566 or 580 env construct as opposed to those observed in cells harboring the control deltaKS or mutant 573 env construct. The wt and mutant Env proteins formed a hetero-oligomer when they were coexpressed. These results demonstrate that zipper motif Env mutants 566 and 580 confer an anti-HIV state to the host CD4+ cells, which indicates that dominant inhibitory mutants targeting the gp41 zipper motif might function as genetic anti-HIV agents to combat HIV-1 infection.

CD4-Positive T-Lymphocytes↗
PubMed1999

Kinetics of germanium dioxide in rats.

The kinetics of germanium dioxide (GeO2) in single dose and repeated exposures were investigated in male Wistar rats. In the single dose GeO2 (100 mg/kg BW, p.o.) exposure study, values of several kinetic parameters were shown as follows, a maximum concentration in serum of 15.5+/-0.7 microg/ml (mean +/- S.E.M.), an absorption half-life of 0.7+/-0.1 h (mean +/- S.E.M.), an elimination half-life of 2.3+/-0.5 h (mean +/- S.E.M.), a distribution of the central compartment Vp (3.1+/-0.3 1, mean +/- S.E.M.), and the apparent volume of distribution of the tissue compartment Vt (8.5+/-2.9 1, mean +/- S.E.M.). In the repeated exposure study, 730+/-92 mg GeO2 in 1 1 double-distilled H2O ( = 100 mg/kg/day) was given daily to rats for 4 weeks (p.o.). After sacrificing the rats, the analysis of tissue distribution showed that GeO2 was accumulated in some important organs or tissues in the body, especially the peripheral nerves and kidney. These results indicate that GeO2 could be absorbed rapidly but had a longer elimination half-life in rats. In addition, GeO2 was accumulated especially in the nerves and kidney following long-term exposure.

Animals↗
PubMed1999

Mouse-to-rabbit xenotransplantation: a new small animal model of hyperacute rejection mediated by the classical complement pathway.

BACKGROUND: Hyperacute rejection of porcine organs transplanted into primate recipients is initiated by the binding of preformed xenoreactive natural antibodies to the vascular endothelium of the graft and activation of the classical complement pathway. Several small animal models are currently employed to study various aspects of xenograft rejection; however, none has been shown to manifest hyperacute rejection mediated by the classical pathway of complement activation. METHODS: We performed heterotopic mouse heart transplants into weanling rabbits, adult rabbits, and C6-deficient rabbits. The recipients received no immunosuppression. Rejected grafts were subjected to histologic analysis and immunofluorescence staining for rabbit IgG, IgM, and C3. Levels of preexisting cytotoxic antibodies as well as classical and alternative complement pathway activities were determined in rabbit serum using mouse red cells as targets. RESULTS: Mean graft survival was 37+/-9.6 min for mouse-to-weanling rabbit transplants (n=10), and 40+/-11.1 min for mouse-to-adult rabbit transplants (n=5). Rejected grafts showed diffuse interstitial hemorrhage, endothelial cell damage, myocyte necrosis, moderate diffuse deposition of rabbit IgG, and dense deposition of rabbit IgM and C3 on the vascular endothelium of the graft, consistent with hyperacute rejection. One mouse-to-C6-deficient rabbit transplant was rejected at 21 hr with severe interstitial hemorrhage, cellular necrosis and a moderate cellular infiltrate consisting primarily of neutrophils and some mononuclear cells. A second transplant in a C6-deficient rabbit was functioning when the recipient died at 6.5 hr as a result of complications of surgery; the graft had normal myocytes and vasculature with minimal spotty interstitial hemorrhage. Both weanling and adult rabbit serum were found to have high titers of cytotoxic IgM anti-mouse antibodies and strong classical complement pathway activity with minimal alternative pathway activity towards mouse red cells. CONCLUSIONS: The mouse-to-rabbit species combination manifests hyperacute xenograft rejection. In vitro studies suggest that this process is mediated by IgM anti-mouse natural antibodies and activation of the classical pathway of complement.

Aging↗