PubMed Health⌕ Search

Biomedical subjects

K Y Hsu

Publications and source records attributed to K Y Hsu.

At least 19 recordsLinked to original sources
PubMed2003

A prospective randomized multi-center study for the treatment of lumbar spinal stenosis with the X STOP interspinous implant: 1-year results.

Patients suffering from neurogenic intermittent claudication secondary to lumbar spinal stenosis have historically been limited to a choice between a decompressive laminectomy with or without fusion or a regimen of non-operative therapies. The X STOP Interspinous Process Distraction System (St. Francis Medical Technologies, Concord, Calif.), a new interspinous implant for patients whose symptoms are exacerbated in extension and relieved in flexion, has been available in Europe since June 2002. This study reports the results from a prospective, randomized trial of the X STOP conducted at nine centers in the U.S. Two hundred patients were enrolled in the study and 191 were treated; 100 received the X STOP and 91 received non-operative therapy (NON OP) as a control. The Zurich Claudication Questionnaire (ZCQ) was the primary outcomes measurement. Validated for lumbar spinal stenosis patients, the ZCQ measures physical function, symptom severity, and patient satisfaction. Patients completed the ZCQ upon enrollment and at follow-up periods of 6 weeks, 6 months, and 1 year. Using the ZCQ criteria, at 6 weeks the success rate was 52% for X STOP patients and 10% for NON OP patients. At 6 months, the success rates were 52 and 9%, respectively, and at 1 year, 59 and 12%. The results of this prospective study indicate that the X STOP offers a significant improvement over non-operative therapies at 1 year with a success rate comparable to published reports for decompressive laminectomy, but with considerably lower morbidity.

Aged↗
PubMed2001

Determination of mephenoxalone in human plasma sample by high-performance liquid chromatography-fluorescence detection.

A simple and sensitive high-performance liquid chromatographic method involving fluorescence detection was developed for the determination of mephenoxalone in human plasma. A Cosmosil 5C18-MS column (250 mm x 4.6 mm I.D., 5 microm) was used as stationary phase and the mobile phase consisted of water-acetic acid-acetonitrile (200:1:300) at a flow-rate of 1.0 ml/min. The fluorescence absorbance was monitored at 280 nm for excitation wavelength and 310 nm for emission wavelength. Temperature control was kept at 40 degrees C for the column. The limit of quantitation achieved was 10 ng/ml, and the standard curve was found to be linear in the concentration range of 10-10,000 ng/ml. Under these analytical conditions, a sufficient mephenoxalone plasma concentration profile could be obtained for pharmacokinetic study.

Chromatography, High Pressure Liquid↗
PubMed2001

Treatment of giant cell tumor of the distal radius.

The results of surgical treatment of giant cell tumors of the distal radius were reviewed in 12 patients between 1982 and 1995. All 12 patients had Grade III lesions. Six of the 12 patients were treated using intralesional curettage with local excision, and the other six patients underwent en bloc resection with total condyle (four of the six by osteoarticular allograft, and the other two by fibular autograft) reconstruction with the aim of preserving the functional joint. There were no early or late complications such as infection, graft fracture, implant failure, or nonunion. No local tumor recurrence was seen in either group during the average followup of 6 years (range, 3-16 years). The best functional result was seen in the patients treated with intralesional curettage. The functional result of the resection group was good, achieving an average of 69% (range, 56%-83%) of their range of motion and 70% (range, 63%-77%) of their grip strength on the contralateral side. Intralesional excision should not be excluded as a possible treatment of Grade III lesions, although en bloc resection was used more commonly for these lesions because of tumor surgery reasons. Grade III lesions were treated with curettage when the tumor did not invade the wrist, destroy more than 50% of the cortex, or break through the cortex with an extraosseous mass in more than one plane. Reconstruction with osteoarticular allograft after en bloc resection is recommended in this non-weightbearing joint when there is contraindication for curettage of the lesion.

Adolescent↗
PubMed2000

Follow-up evaluation of resected lumbar vertebral chordoma over 11 years: a case report.

STUDY DESIGN: A case report with an 11-year follow-up assessment after resection and reconstruction for lumbar chordoma is given. The literature relevant to this topic is reviewed. OBJECTIVES: To report the long-term outcome in a case of lumbar chordoma, to review the literature on vertebral chordoma, and to outline the rationale for surgical resection in such cases. SUMMARY OF BACKGROUND DATA: Chordoma is a malignant bone tumor that grows slowly, often recurs locally, and metastasizes late. Although different treatment approaches exist, including radiation and surgery, the only curative treatment is early and complete surgical excision of the tumor. Immediate spinal stability must be achieved with appropriate replacement or bone graft with rigid fixation. METHODS: The 11-year follow-up evaluation of a 42-year-old woman with L3 and L4 vertebral body chordoma treated with complete removal, femoral shaft allograft replacement, fusion, and rigid metal fixation is reported. The patient was observed with serial physical examinations, radiographs, and laboratory studies over 11 years. RESULTS: At this writing, 11 years after the resection of the L3 and L4 chordoma, the patient is asymptomatic without evidence of recurrence or metastasis. CONCLUSIONS: As reported, vertebral chordomas are not curable, but the authors' experience contradicts this. The surgeon should aim at a wide, or at least a marginal, excision followed by a stable reconstruction.

Adult↗
PubMed2000

Butachlor, a suspected carcinogen, alters growth and transformation characteristics of mouse liver cells.

Butachlor is a widely used herbicide in Asia and South America. Previous investigations have indicated that it is a suspected carcinogen. To understand more about the biological effects of butachlor on cultured cells and the mechanism(s) of its carcinogenicity, we studied the alteration of the growth characteristics that was induced by butachlor in normal mouse liver cells (BNL CL2). This study demonstrates that butachlor decreases the population-doubling time of BNL CL2 cells, suggesting that it stimulates cell proliferation. To support this finding, a thymidine incorporation assay was conducted and a similar result that butachlor stimulates cell proliferation was elucidated. In addition, we show that butachlor increases the saturation density of the BNL CL2 cells. When combined with the tumor initiator N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), butachlor transforms cells efficiently, as demonstrated by loss of contact inhibition. These findings indicate that butachlor alters the growth characteristics of BNL CL2 cells and suggest that butachlor may induce malignant transformation through stimulation of cell proliferation, alteration of cell cycle regulation, and suppression of cell density-dependent inhibition of proliferation.

Acetanilides↗
PubMed1999

Metabolic kinetics of p-aminobenzoic acid in rabbits.

The metabolic kinetics of p-aminobenzoic acid (PABA) in rabbits was studied. PABA is predominantly metabolized by acetylation and glycine conjugation to form p-acetamidobenzoic acid (PAABA), p-aminohippuric acid (PAHA), and p-acetamidohippuric acid (PAAHA). After PABA IV administration (20 mg/kg) to rapid (n=16) and slow (n=8) acetylation rabbits, PABA was eliminated rapidly. The half-lives of PABA were 7.01+/-0.32 min in rapid acetylation rabbits and 7.08+/-0.78 min in slow acetylation rabbits. Significant differences were obtained in formation of PAABA and PAHA formed from PABA in both acetylation phenotype rabbits. The formation fraction of PAABA, formed by acetylation of PABA, was 0.8029+/-0.0267 in rapid acetylators and 0.2385+/-0.0428 in slow acetylators (p<0.001). PAHA formed from PABA was 0.0462+/-0.0102 in rapid acetylators and 0. 6652+/-0.0562 in slow acetylators (p<0.001). Only 0.0156+/-0.0030 of PABA could be detected as PAAHA in rapid acetylation rabbits which was obtained by acetylation of PAHA. After individual IV injection of PAHA, PAAHA, and PAABA to both phenotypes of rabbits, PAABA and PAAHA were eliminated in their unchanged forms whereas PAHA was further acetylated to form PAAHA. The formation fraction of PAAHA formed from the acetylation of PAHA was 0.4408+/-0.0570 in rapid acetylators and 0.0539+/-0.0084 in slow acetylators (p=0.002). From the results obtained, metabolic pathways of PABA show significant differences in both acetylation phenotypes of rabbits. Acetylation is the major metabolic route of PABA in rapid acetylation rabbits, while glycine conjugation is more predominant in slow acetylation rabbits.

4-Aminobenzoic Acid↗
PubMed1999

Video-assisted thoracoscopic surgery to the upper thoracic spine.

BACKGROUND: The standard open technique for exposure of the upper thoracic spine, T1-T4, usually requires a difficult thoracotomy. From November 1, 1995 to June 30, 1997, eight patients underwent video-assisted thoracoscopic spinal surgery in our institute to treat their upper thoracic spinal lesions endoscopically. METHODS: A new approach, the so-called "extended manipulating channel method," was used in this series that allows the combined use of video-assisted thoracoscopy and conventional spinal instruments to enter the chest cavity freely for the procedures. Patients' ages ranged from 44 to 89 years (average, 60 years). Definitive diagnoses included two pyogenic spondylitis and six spinal metastases. Five patients presented initially with myelopathy. RESULTS: There were no deaths or neurologic injuries associated with this technique. The mean surgical time was 3.1 h. The mean duration of chest tube retention was 3.3 days. The mean total blood loss was 1,038 ml, and two patients had a blood loss of more than 2,000 ml owing to bleeding from epidural veins or raw osseous surfaces. Complications included one superficial wound infection and one subcutaneous emphysema that resolved spontaneously. In this series, there was no need of conversion to open thoracotomy for the patients. CONCLUSIONS: The thoracoscopy-assisted spinal technique using the extended manipulating channels, usually 2.5-3.5 cm, allows variable instrument angulations for manipulation. The mean surgical time (3.1 h) was considered no longer than for an open technique for the equivalent anterior procedure. Such an approach can achieve less procedure-related trauma and has proved to be a good alternative to other treatment modalities.

Adult↗
PubMed1999

Management of aggressive benign and malignant bone tumors of the shoulder region.

BACKGROUND: The shoulder girdle is one of the most common sites of aggressive malignant and benign bone tumors. Curative resections and sparing of the limb are possible. However, reconstruction methods remain a challenge and the functional results vary. METHODS: Fourteen patients with aggressive benign or malignant bone tumors about the shoulder girdle who were treated with surgical resection with possible need for reconstructions were retrospectively analyzed. There were 8 men and 6 women. Their ages ranged from 15 to 70 years; the mean age at operation was 36 years. Ten patients had malignant bone tumors and four had extensive giant-cell tumors. A variety of reconstructive procedures were performed after resection of the tumors. The choice of procedure depended on the type of resection and the needs of the patients. Supplementary chemotherapy or radiotherapy was undertaken after surgical procedures in 9 patients. RESULTS: The length of follow up ranged from 16 months to 10 years. The functional results were described and graded quantitatively according to the functional rating system of the Musculoskeletal Tumor Society. Overall, 6 patients achieved excellent and good shoulder functions at follow-up examination, while 8 acquired fair or poor functional results. Four patients died from lung metastasis, while 10 survived and are disease free. Resection of the glenoid cavity and the proximal part of the humerus with loss of the abductor mechanism resulted in poor function of the shoulder. CONCLUSION: The choice of treatment options depended upon the staging of tumors, the extent of resection, the needs of individual patients, the preservation and reconstruction of rotator cuff, the experience of surgeons, and the facilities at the hospital. The functional results were related to the area of involvement and the type of resection. The preservation of the abductor mechanism provided good functional results.

Adolescent↗
PubMed1998

Semistructural allografting in bone defects after curettage.

BACKGROUND AND OBJECTIVES: A variety of aggressive benign bone tumors often require wide bone and soft tissue excision for adequate local control, but this creates a large defect and a seriously weakened extremity. Restoration of limb function presents a difficult problem. METHODS: The treatment of 104 patients with space occupying lesions of the long bone were analyzed. Deep-frozen (-70 degrees C) cortical strut allografts with or without allogeneic cancellous bone graft were implanted into the defects after extensive intralesional curettage. Thirty-six patients had fibrous dysplasias, 29 unicameral bone cysts, 22 giant cell tumors, 12 aneurysmal bone cysts, 3 benign fibrous histiocytomas, and 2 ossifying fibromas. Fifty-six patients had pathologic fracture. The average volume after curettage was 210 ml (range 60-460 ml). The average follow-up period was 50 months. RESULTS: At follow-up evaluation, the radiographs demonstrated complete incorporation of the allogeneic implant and new bone formation in the cavity in 83% of the patients (86/104). All fractures healed. There was no local recurrence or fracture of the cortical graft; neither were there other serious complications except one avascular necrosis of the femoral head. Good or excellent functional results were found in 97% (101/104) of the patients. CONCLUSIONS: For large osseous defects, the reconstructive technique using cortical stent allograft provides increased strength, easy fixation, remodeling of the cystic defect, and healing of the fracture and prevents deformity. However, remodeling occurs slowly and may never be complete.

Adolescent↗
PubMed1998

Preparation and characterization of heparin-containing SBS-g-DMAEMA copolymer membrane.

The grafting of dimethyl amino ethyl methacrylate (DMAEMA) onto styrene-butadiene-styrene triblock copolymer (SBS) membrane was subsequently conducted by UV-radiation induced graft copolymerization without degassing to obtain the SBS-g-DMAEMA copolymer membrane. The substituted amino groups on the SBS-g-DMAEMA graft copolymer membrane were quaternized with iodomethane, and then the membrane was treated with heparin to prepare the heparin-containing SBS-g-DMAEMA copolymer membrane (SBS-g-DMAEMA-HEP). The graft copolymer membrane (SBS-g-DMAEMA) and the heparin-containing SBS-g-DMAEMA copolymer membrane (SBS-g-DMAEMA-HEP) were characterized by FTIR spectroscopy. The heparin content was determined by toluidine blue heparin assay. Contact angle, water content, and protein adsorption of fibrinogen and albumin experiments were also performed to evaluate the effect of graft amount and heparin content on the biocompatibility of SBS-g-DMAEMA and SBS-g-DMAEMA-HEP graft copolymer membranes. By using Kaelble's equation, the surface tension of SBS-g-DMAEMA and SBS-g-DMAEMA-HEP were determined. It was found that with increasing grafting amount and the heparin content, the surface tension and water content of SBS-g-DMAEMA membrane increased, whereas the contact angle decreased. The amount of the adsorption of albumin and fibrinogen decreased with increasing graft amount and heparin content. However, there was a minimum for adsorption of proteins in the SBS-g-DMAEMA and SBS-g-DMAEMA-HEP membranes.

Biocompatible Materials↗
PubMed1998

Analysis of techniques for video-assisted thoracoscopic internal fixation of the spine.

Between November 1, 1995, and January 31, 1996, four separate thoracoscopic spinal fixation surgeries were performed via extended manipulating channels using the so-called three-portal technique. The diagnoses included three spinal metastases and one T11 burst fracture. All patients had myelopathy at presentation. Using the three-portal technique, the conventional spinal instruments and fixation devices could be passed freely through the extended manipulating channels (usually 3-4 cm) into the chest cavity and manipulated by techniques similar to those used in standard open procedures. A reduction-fixation spinal plate with variable screw and plate anchoring angles was successfully inserted in the procedures. The total length of the operation ranged from 3.5 to 5 h (average 4.3 h), and the total blood loss was 1000-2500 ml (average 1500 ml). There were no intraoperative deaths, and no patient showed neurological deterioration following the procedures. On the basis of these results, we believe that the combination of video-assisted thoracoscopy and conventional spinal instruments presented in this report would be an ideal method for performing these procedures. Throughout the operation, only one trocar was employed for introducing the thoracoscope. The thoracoports were used temporarily during tumor tissue retrievals. This technique makes thoracoscopy-assisted spinal fixation simple and easy. It allows greater control of intraoperative vessel bleeding and reduces the number of portals required during the procedure (on average to 3). In addition, the technique reduced the amount of endoscopic materials required for the procedure, thus reducing the cost of treatment.

Adult↗
PubMed1998

Subtalar distractional realignment arthrodesis with wedge bone grafting and lateral decompression for calcaneal malunion.

BACKGROUND: The purpose of this study was to evaluate prospectively the efficacy of subtalar distractional realignment arthrodesis in the treatment of calcaneal malunion associated with subtalar arthritis, collapse of height, talonavicular subluxation, malalignment of the heel axis, and widening heel with calcaneofibular abutment. METHODS: Thirty-four patients with severe calcaneal malunion were treated with a lateral approach, lateral decompression, medial subtalar capsulotomy, and distraction and realignment of the subtalar joint with an anteriorly and laterally tapered wedge bone graft. The patients were evaluated with a functional rating scale and radiographs, both before and after surgery. RESULTS: Thirty-two of the 34 patients were evaluated at a mean of 71 months (range, 60-92 months) after the arthrodesis. Solid subtalar fusion was achieved in 31 of the 32 patients. The average gain of subtalar distraction was 12 mm. Neutral or mild valgus alignment was achieved in 26 of the 32 patients. The mean postoperative score (83) showed significant improvement over the mean preoperative score (47). Overall, the functional rating scale revealed excellent or good results in 26 patients and fair results in 6 patients. CONCLUSION: Coupled with wedge bone grafting, the subtalar distractional realignment arthrodesis achieved restoration of hindfoot height and axial alignment with a good union rate and significant improvement in the majority of patients with calcaneal malunion.

Adult↗
PubMed1998

Treatment of fibrous dysplasia involving the proximal femur.

Twenty-two patients with fibrous dysplasia in the femoral neck or trochanteric area were treated with curettage and bone grafting with a sliding hip compression screw and plate. Follow-up ranged from 2 to 6 years (average: 4 years). Fourteen patients had monostotic and 8 had polyostotic disease. Four patients had pathologic fractures. Bone grafting included a deep-frozen allogeneic cortical strut and cancellous bone. After implanting the lag screw and cortical strut, the remaining defect space was filled with iliac bone. Postoperatively, all patients had good bone healing and complete incorporation of the implanted graft. There were no recurrences or complications, and functional results were rated as good and excellent.

Adult↗
PubMed1998

Long-term continuous infusion of propofol as a means of sedation for patients in intensive care unit: relationship between dosage and serum concentration.

BACKGROUND: We studied the effect of long-term continuous propofol infusion in patients who were utilizing mechanical ventilation in intensive care unit. The purpose of our study was to identify the appropriate dosage of propofol and to monitor the relating serum level that would provide satisfactory sedative and hypnotic effects to the patients, i.e., to procure a Ramsay Sedation Scale (RSS) value between 2 and 3. METHODS: Ten mechanically ventilated ICU patients were studied. The syringe pump was set to deliver propofol at a rate of 1 mg/kg/h without an initial loading dose. After continuous infusion of propofol for 24 h, in each patient 5 ml of whole blood was sampled daily for one week. All samples were analyzed for serum level of propofol by high performance liquid chromatography. RESULTS: When the Ramsay Sedation Scale (RSS) value was between 2 and 3, the mean dosage of infused propofol was 0.71 +/- 0.31 mg/kg/h (ranging from 0.58 to 1.27 mg/kg/h) and the mean plasma concentration was 0.58 +/- 0.22 microgram/ml (ranging from 0.20 to 0.86 microgram/ml). The lipid serum level was measured in three patients whose infusion duration was greater than 14 days. The respective level was 321 mg/dl, 139 mg/dl, and 99 mg/dl. The first patient died from multiple organ failure as a result of multiple trauma. Four patients simultaneously received infusion of propofol and muscle relaxant. CONCLUSIONS: We concluded that propofol infusion given at a rate of 0.71 +/- 0.31 mg/kg/h and a plasma concentration level of less than 1 microgram/ml would be sufficient to produce a sedation with RSS value between 2 and 3.

Adult↗
PubMed1997

Preparation and properties of SBS-g-DMAEMA copolymer membrane by ultraviolet radiation.

A styrene-butadiene-styrene triblock copolymer (SBS) membrane was prepared by solvent casting. Grafting of dimethyl amino ethyl methacrylate (DMAEMA) to this SBS membrane was subsequently conducted by ultraviolet radiation-induced graft copolymerization without degassing to obtain a SBS-g-DMAEMA copolymer membrane. The graft copolymer was characterized by infrared spectroscopy and scanning electron microscopy. The degree of grafting and the mechanical properties of SBS and SBS-g-DMAEMA were measured. Contact angle, water content, and protein absorption of fibrinogen and albumin experiments were also performed to evaluate the biocompatibility of SBS-g-DMAEMA graft copolymer membranes. It was found that the degree of grafting was related to the irradiation time, DMAEMA concentration, and temperature. The tensile strength of the SBS-g-DMAEMA membrane increased with an increase in the degree of grafting. By using Kaelble's equation and the contact angle data, the surface tension of SBS-g-DMAEMA was determined. It was found that with an increase in the degree of grafting, the surface tension and water content of SBS-g-DMAEMA membrane increased, whereas the contact angle decreased. The amount of absorption of albumin and fibrinogen decreased with an increase in amount of grafting. However, there was a minimum for the adsorption of proteins in the SBS-g-DMAEMA membrane.

Absorption↗
PubMed1997

A dose-dependent pharmacokinetic study on caffeic acid in rabbits after intravenous administration.

The dose-dependent pharmacokinetics of caffeic acid (CA) were studied in rabbits. Three different doses (5, 10, and 25 mg kg-1) were administered intravenously to six rabbits each. The concentration-time profiles for CA could be fitted by a two-compartment model for each dose. The results showed that total-body clearance and elimination rate constant from the central compartment (k10) after a 5 mg kg-1 dose were greater than those after the other two doses. Furthermore, the terminal elimination half-life (beta half-life) and mean residence time (MRT) after a 5 mg kg-1 dose were less than after the other doses. The AUC value increased linearly with dose within the range of 10-25 mg kg-1. Most of the unchanged caffeic acid was excreted in the urine within 2 h. The percentage of unchanged caffeic acid excreted in the urine was 63.4, 60.0, and 55.4% after doses of 5, 10, and 25 mg kg-1, respectively, which was not significantly different. However, significant differences in the renal clearances and renal excretion rate constants were observed with a 5 mg kg-1 dose compared to the other doses. On the other hand, nonrenal clearances and nonrenal excretion rate constants showed no dose-related differences. The differences observed in total-body clearance, k10, beta half-life, and MRT between a 5 mg kg-1 dose and the other doses can be explained on the basis of the differences in renal clearance and renal excretion rate constants.

Analysis of Variance↗
PubMed1997

Video-assisted thoracoscopic treatment of spinal lesions in the thoracolumbar junction.

BACKGROUND: The endoscopic treatment of spinal lesions in the thoracolumbar junction (T11-L2) poses a great challenge to the surgeon. From November 1, 1995 to December 31, 1996, we successfully used a combination of video-assisted thoracoscopy and conventional spinal instruments to treat 38 patients with anterior spinal lesions. Twelve of them had lesions in the thoracolumbar junction. METHODS: The so-called extended manipulating channel method was used to perform vertebral biopsy, discectomy, decompressive corpectomy, interbody fusions, and/or internal fixations in these patients. The size of the thoracoscopic portals was greater than usual in order to allow conventional spinal instruments and a thoracoscope to enter the chest cavity freely and be manipulated by techniques similar to those used in standard open surgical procedures. In this series, the procedures were performed by using either a three-portal approach (2. 5-3.5 cm) or a modified two-portal technique involving a 5-6 cm larger incision and a small one for introducing the scope. RESULTS: None of the operations resulted in injury to the great vessels, internal organs, or spinal cord. The total time for the operation ranged from 1.5 to 4.5 h (average, 3); and the total blood loss ranged from 50 to 3000 cc (average, 1050). One patient was converted to an open procedure due to severe pleural adhesion. Complications included two instances of transient intercostal neuralgia, one superfical wound infection, and one residual pneumothorax. CONCLUSIONS: The video-assisted technique with the extended manipulating channel method presented in this report simplifies thoracoscopic spinal surgery in the thoracolumbar junction and makes it easier. It avoids division of the diaphragm, removal of the rib, and wide spread of the intercostal space, and it allows greater control of intraoperative vessel bleeding. Using this technique, the number of portals required during the procedure can be reduced. In addition, the technique reduces the endoscopic materials required, thus lowering overall cost. It is an effective and promising approach.

Adult↗