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Biomedical subjects

W C Cheng

Publications and source records attributed to W C Cheng.

At least 37 records · Page 2Linked to original sources
PubMed1998

A simple program to calculate codon bias index.

A computer program (PCBI) was developed to quickly calculate codon bias index (CBI). PCBI can analyze a gene containing introns. The 22 preferred codons defined from Saccharomyces cerevisiae were used in PCBI as the standard to measure the CBI values. However, users can modify the preferred codons to suit each organism. The data PCBI provides include DNA sequence of open reading frame without introns, amino acid sequence of gene product, a table of amino acid composition, a table of codon usage and (G + C) content, parameters for calculating CBI, and the value of CBI. PCBI runs on a DOS or Windows environment, but results can be saved in ASCII text format.

Amino Acids↗
PubMed1997

Reoperation for recurrent trigeminal neuralgia after microvascular decompression.

BACKGROUND: Microvascular decompression (MVD) is an effective technique for those who have trigeminal neuralgia (TN) but cannot tolerate, or show no response to medicine. Though the initial success rate is high, some patients may develop severe recurrent neuralgia, especially after a longer period of follow-up. The efficacy of reoperation needs to be evaluated. To know the possible risk factors of recurrence after initial MVD is mandatory to the management of recurrent TN. METHODS: Among the 80 cases of TN treated with MVD, five cases showed severe recurrent symptoms within a follow-up period from 9 months-4 years. The symptoms recurred on the same side of the face, and were unresponsive to medical treatment. Brain computed tomography (CT) and magnetic resonance imaging (MRI) may reveal the etiology of recurrence. Repeat decompression of the trigeminal nerve was the main goal of reoperation, which was done via a suboccipital approach. RESULTS: Over the past 17 years, 80 MVDs for TN have been performed at Chang Gung Memorial Hospital. There were five cases of serious postoperative recurrence, which could not be relieved by medicine. Recurrence occurred 1 day-12 months after the initial surgery. Three cases were due to vascular compression, while two were caused by the local effect of Teflon felt. Reoperation produced complete remission in four patients, and partial remission in one. CONCLUSIONS: An increasing number of patients may experience severe recurrent TN after initial MVD during a long period of follow-up. Reoperation is safe and beneficial for these patients, but the results are dependent on the etiology of the recurrence. Further vascular compression of the trigeminal nerve can be relieved by MVD. Otherwise, in cases of severe adhesion caused by Teflon, complete microneural lysis can achieve satisfactory results.

Adult↗
PubMed1997

Bone densitometry of proximal femur in Chinese subjects: gender differences in bone mass and bone areas.

Bone mineral content (BMC), bone areas (BA), and bone mineral density (BMD) of the proximal femur were measured in 202 healthy Chinese men and 507 healthy Chinese women, aged 21-70 years, to investigate gender differences in densitometry of the femur. Densitometric values measured at the femoral neck, trochanter, and Ward's triangle were generally greater in men than women of the same age, except at Ward's triangle. While BMD decreased with aging with similar slopes of -0.2 approximately -1% per year, the actual readings were 10%-15% lower than those of Caucasian subjects of the same age and gender for Chinese men and women. Furthermore, with increasing age, trochanteric BA increased in women but not in men, and femoral neck BA increased in men but not in women. These different trends of change in bone dimensions were independent of weight or height. They may reflect a structural difference at the proximal femur and imply differences in mechanical strength, and thus may have played some roles in the different incidence of hip fractures between the elderly men and women.

Absorptiometry, Photon↗
PubMed1997

Effect of bone area on spine density in Chinese men and women in Taiwan.

Areal bone mineral density (BMD), the quotient of bone mineral content (BMC) divided by the projectional bone area (BA), measured with dual-energy X-ray absorptiometers (DXA), is the most common parameter used today to evaluate spinal osteoporosis. To evaluate whether gender, age, weight, and height can determine spinal BA, and to compare BA and analyze its effects on spinal density in the two genders, we measured BA and BMC, and calculated areal BMD, and the bone mineral apparent density (BMAD = BMD/the square root of BA) of the L-2 to L-4 vertebrae of 604 female and 223 male Chinese volunteers from 20 to 70 years of age using a Norland XR-26 DXA. Standardized for height and weight, BA showed a relatively large variation and a significant increase with increasing age in both genders. On the other hand, BMC stayed unchanged in men > 50 years of age and decreased with aging in postmenopausal women. Younger men (< 51 years) had a much larger mean BA (by 15.5%) and larger mean BMC (only 10%) than that of age-matched women. As a result, younger men had a slightly and significantly lower areal BMD (by 7.1%) and a much lower BMAD (by 16%) (p < 0.0001 for both) than premenopausal women of similar age. Men had higher areal BMD and BMAD values than age-matched women only after age 50 years. Although taller body height, heavier weight, and increasing age were associated with a larger BA, these factors could not explain most of the interindividual variations in BA in both genders. Thus anteroposterior BA of lumbar vertebrae measured with DXA seems to affect the areal BMD and BMAD readings in the two genders. The larger BA caused a low BMAD and probably underestimated the true volumetric spine density in men.

Absorptiometry, Photon↗
PubMed1997

Effect of exercise and exogenous glucocorticoid on serum level of intact parathyroid hormone.

Most previous studies suggest that physical exercise, or physiological response to exercise such as cortisol and adrenaline secretion regulate parathyroid hormone (PTH) secretion in humans. To investigate the effects and possible interaction of exercise and excessive glucocorticoid on PTH secretion, we examined the serum of levels of intact-PTH, cortisol, adrenocorticotrophic hormone (ACTH), calcium, magnesium and phosphorus before and during one-hour of bicycle-ergometric exercise at 60% of maximal oxygen uptake. These exercise tests were performed on eight Chinese male volunteers aged between 20 and 25 years, once with and once without pretreatment with 0.5 mg of dexamethasone taken orally 9.5 hours in advance. The results showed that dexamethasone pretreatment significantly lowered basal levels of cortisol and ACTH, but intact PTH did not change. After 60 minutes of bicycling, intact PTH level increases by 50% of baseline both with and without dexamethasone pretreatment. Serum levels of calcium, corrected for changes in serum albumin concentration, phosphorus and magnesium also increased in both cases. This study demonstrated an increase of intact-PTH with exercise which was not associated with hypocalcemia or hypomagnesemia, and was not altered in the presence of mild exogenous glucocorticoid excess and suppressed endogenous cortisol secretion.

Adrenocorticotropic Hormone↗
PubMed1996

Sexual differences in bone markers and bone mineral density of normal Chinese.

We measured bone mineral density (BMD) at lumbar (L2-L4) vertebrae and proximal femurs of 385 healthy Chinese women aged 40-70 years and 156 healthy Chinese men aged 20-85, and four markers-bone alkaline phosphatase isozyme (BAP), procollagen-I C terminal propeptide (PICP), osteocalcin (BGP) in serum, and a bone resorption marker, urinary cross-linked N-telopeptide of type I collagen (NTX), of these subjects. The results indicate that in postmenopausal women, levels of all the markers increased with age. In men, serum BAP, PICP, and urinary NTX decreased significantly, and serum BGP decreased with borderline significance (P = 0.08). With increasing age, bone density decreased at both sites in postmenopausal women and at the proximal femur in men. The lumbar bone density showed no significant age-related changes in men. In premenopausal women, BMD at either site showed no significant change with increasing age. Despite the different trends between men and women of age-related changes in BMD and bone markers, bone density of both proximal femur and spine in both sexes correlated inversely with levels of the bone markers in a manner independent of age or body weight. The meaning of opposite age effects on bone markers in men and women needs further investigation. In addition, higher bone marker levels, implying faster bone turnover rate, are associated with lower BMD in both sexes.

Adult↗
PubMed1996

Bone mineral density and bone markers in relation to vitamin D receptor gene polymorphisms in Chinese men and women.

Whether vitamin D receptor gene (VDRG) polymorphism can be used as a predictor for bone turnover rate or bone mass remains controversial. Its role within various ethnic populations are also unsettled. We examined VDRG polymorphism using restrictive enzymes Bsm-I, Apa-I, and Taq-I in 155 men aged 22-88 and 113 premenopausal women aged 40-53. The bone mineral density (BMD) of the vertebrae (L2-4), proximal femur, and total body bone mineral content (tb-BMC) (women only), as well as urinary N-terminal crosslinked fragment of type I collagen (NTX), serum osteocalcin, bone isozyme of alkaline phosphatase, and caboxyterminal propeptide of type I procollagen levels were measured. Chinese men and women exhibited a low prevalence for B (absence of Bsm-I restriction site) phenotypes than white and Japanese. Within the tested samples there were 0.4% BB homozygotes, 6.7% Bb heterozygotes, and 93% bb homozygotes. The distributions of Apa-I polymorphism (9.0% AA, 42.5% Aa, and 48.5% aa) also differed from those reported for the white populations. Most of the Chinese men and women were TT homozygous (96.6%). A comparison of actual values and values adjusted for age and weight of tb-BMC and BMD at the lumbar spine, Trochanter, Ward's triangle, and femoral neck showed no significant difference among three subgroups in each of the three sets of polymorphism. Furthermore, the actual values and adjusted values (adjusted for age) of the four bone markers, respectively, showed no significant differences. We conclude that given the very low prevalence of the suspected high risk genotypes (B, A, and t), and the lack of difference among the polymorphic subgroups, VDRG polymorphism may not be an important determinant of the bone turnover rate and bone mass of Chinese men and women.

Adult↗
PubMed1996

The impact of ovarian cystectomy on ovarian response to stimulation during in-vitro fertilization cycles.

This study was carried out to investigate whether ovarian cystectomy interferes with follicular recruitment and the number of oocytes retrieved in an in-vitro fertilization (IVF) cycle. Patients who had previously undergone unilateral ovarian cystectomy (n = 90) and control patients (n = 90) with no history of ovarian surgery were included in our study. The parameters compared were the number of follicles recruited and the number of oocytes obtained from each ovary. In patients who had undergone surgery, the normal ovaries recruited a significantly higher number of follicles (P < 0.001) and yielded a significantly higher number of oocytes (P < 0.001) compared with the contralateral ovaries which had undergone cystectomy. In the control patients, no significant differences were identified between the left and right ovaries. These results demonstrate that ovarian cystectomy reduces follicle and oocyte numbers in ovulation induction cycles.

Adult↗
PubMed1996

Ultrasound derived indices of follicular blood flow before HCG administration and the prediction of oocyte recovery and preimplantation embryo quality.

The principal aim of the study was to relate ultrasound-derived indices of blood flow in individual follicles on the day of, but before, the administration of human chorionic gonadotrophin (HCG) to the subsequent recovery of oocytes and the production of preimplantation embryos. Data were obtained from 21 women (aged 29-43 years) with bilateral tubal occlusion, who were undergoing treatment by in-vitro fertilization (IVF) and embryo transfer. Transvaginal ultrasonography with colour Doppler imaging and pulsed Doppler spectral analysis were used to measure follicular volume and derive indices of blood flow. The end-points for each follicle were the volume, peak systolic velocity (PSV), pulsatility index (PI), and the recovery or non-recovery of an oocyte, the subsequent production or non-production of a preimplantation embryo and the morphological grade of each embryo. A total of 94 follicles were studied; 74 oocytes were recovered (79%) and 40 embryos (33 grade I or II) were produced. There were four clinical pregnancies (pregnancy rate 25.0% per transfer, 19.0% per patient). There was a significant correlation between whether or not follicular blood flow was detected and whether or not an oocyte was recovered (P < 0.05, chi 2 test). The values for volume and PI were not clinically useful. The PSV (cm/s, mean +/- SD) was higher in follicles that were associated with the production of an embryo (12.7 +/- 5.9) compared with those that were not (8.5 +/- 5.0; P < 0.05, Student's t-test). The probability of producing a grade I or grade II embryo was 75% if the PSV was > or = 10 cm/s. The corresponding value was 40% if the PSV was < 10 cm/s and 24% if blood flow was not detected (i.e. PSV < 3 cm/s). There was a significant increase (P < 0.05, Student's t-test) in the PSV before aspiration in those follicles associated with the subsequent production of an embryo. We conclude that the value for PSV, before the administration of HCG, can be used to identify follicles with a high probability of producing an oocyte and a high grade preimplantation embryo. The information may also be used to time the administration of HCG to achieve the optimum number and quality of embryos for patient management.

Adult↗
PubMed1995

Combination chemotherapy with carmustine and cisplatin before, during, and after radiotherapy for adult malignant gliomas.

Twenty-two patients, aged 16 to 67, who had malignant gliomas after surgical resection were treated with carmustine and cisplatin intravenous infusion before, during, and after radiotherapy. All patients had subtotal or total resection, or biopsy as the initial procedure. Twenty-one patients who had at least 2 cycles of chemotherapy and finished the whole course of radiotherapy were considered to be evaluable for responses. Among them, 5 had glioblastoma multiforme, 16 had anaplastic astrocytoma. The median time to tumor progression was 35 weeks (range 12-130 weeks) and median survival time was 66 weeks (range 10-156 weeks). Early progression occurred more frequently in patients with biopsy only and subtotal resection, and in patients with glioblastoma than in those with anaplastic astrocytoma. This combined modality treatment program was associated with reversible hematologic toxicity which was severe in 2 patients, and with ototoxicity in 1 patient, nephrotoxicity in 2 patients. Combination of carmustine and cisplatin with cranial irradiation for malignant gliomas is moderately toxic and appears to offer no obvious survival advantage compared with radiation therapy plus BCNU alone.

Adolescent↗
PubMed1995

Pituitary down-regulation prior to in-vitro fertilization and embryo transfer: a comparison between a single dose of Zoladex depot and multiple daily doses of Suprefact.

In order to further evaluate the endocrinological, embryological and clinical efficacy of a single injection of the gonadotrophin-releasing hormone (GnRH) analogue Zoladex (goserelin), 142 women underwent pituitary down-regulation prior to in-vitro fertilization and embryo transfer: 71 with a single injection of Zoladex depot (group I) and 71 matched controls with multiple daily injections of Suprefact (buserelin; group II). Ovarian stimulation was performed with human menopausal gonadotrophin (HMG) and ovulation induction with human chorionic gonadotrophin (HCG). HMG and hydroxyprogesterone caproate depot were given for luteal phase support. The mean (+/- SD) age (34.01 +/- 4.42 versus 34.81 +/- 4.00 years), mean total dosage of HMG (61.25 +/- 26.87 versus 56.17 +/- 25.18 ampoules), mean daily dosage of HMG (4.74 versus 4.94 ampoules), duration of HMG stimulation (12.91 +/- 3.68 versus 11.31 +/- 3.46 days) and oestradiol concentration on the day of HCG (10,082 +/- 8007 versus 9440 +/- 7840 pmol/l) were similar in both groups but the mean total number of injections (GnRH and HMG) (13.55 +/- 3.35 versus 55.37 +/- 31.92) was significantly lower in group I. Furthermore, the proportion of women down-regulated by 2 weeks and pregnancy rate per embryo transfer were significantly higher in the Zoladex group, while miscarriage rates were similar. We conclude that a single dose of Zoladex is quicker, more convenient and should be investigated as an equally effective alternative to multiple doses of Suprefact for pituitary down-regulation prior to assisted conception. Further studies are required to test the teratogenicity and effectiveness of Zoladex.

Adult↗
PubMed1995

Postictal neurogenic pulmonary edema during uncal herniation--a case report and literature review.

A 13-year-old boy fell off a tree and developed an acute subdural hematoma (SDH) which was treated conservatively because the patient was fully conscious. After a generalized tonic-clonic seizure, he manifested signs of uncal herniation and neurogenic pulmonary edema (NPE). The patient made a good recovery after craniotomy and evacuation of the SDH with intensive pulmonary care. Though rare, uncomplicated postictal NPE in children almost runs a smooth course with favorable outcomes. However, the mortality rate is high in postictal NPE complicating cerebral herniation, and it seems an exception that our patient made a good recovery.

Acute Disease↗
PubMed1994

Surgical treatment for ossification of the posterior longitudinal ligament of the cervical spine.

Ossification of the posterior longitudinal ligament (OPLL) is a degenerative disease of the spine, usually found in the cervical vertebrae. Most symptomatic patients present with a myelopathy or myeloradiculopathy. Surgical decompression is the preferred treatment. The choice of operative approach, anterior or posterior, is still controversial. From January 1986 to June 1992, 20 patients with this condition received operations at Chang Gung Memorial Hospital. The clinical manifestations and the results of treatment are analysed. The ideal surgery seems to be the anterior approach with bone fusion. If, however, the OPLL involves more than three segments, the posterior approach with an expansive laminoplasty would be the better alternative technique.

Adult↗
PubMed1994

Chylothorax after endoscopic sympathectomy: case report.

Endoscopic sympathectomy is a new trend for the treatment of hyperhidrosis palmaris. It is a simple and effective technique; however, it carries some recognized risks such as Horner's syndrome and pneumohemothorax. We recently encountered a case complicated by the development of a chylothorax. The patient was a 23-year-old healthy women with profuse palmar sweating. She developed an intractable dry cough after a transthoracic endoscopic sympathectomy. A chest x-ray revealed a left pleural effusion. A chylous effusion was found after thoracentesis and fluid analysis. The pleural effusion resolved after chest tube drainage and diet control. Although endoscopic sympathectomy is a simple and quick procedure, unusual complications, such as chylothorax, may occur. Appropriate early recognition and treatment can prevent a disastrous result.

Adult↗
PubMed1994

Psychosocial needs of family caregivers of terminally ill patients.

The primary caregivers (mean age = 63 yr.) of 28 terminally ill veterans (mean age = 67 yr.) who were living at home were surveyed for their concrete and psychosocial needs. The caregivers also completed the Beck Depression Inventory, the Life Satisfaction Index, the Provision of Social Relations scale, and the Burden Inventory. The rank order of concrete and psychosocial needs is reported for these caregivers. Increased scores on depression were associated with decreased life satisfaction as was low social support. Not surprisingly, higher numbers of concrete and psychosocial needs were associated with increases in depression.

Adult↗
PubMed1994

Benign osteoblastoma of the spine--report of two cases.

Benign osteoblastoma is a rare spinal tumor, with the posterior element mainly involved. Symptoms do vary and there is a long diagnostic delay, especially in young people. We present two cases of benign osteoblastoma. One occurred in the atlas and presented with a painless neck mass. The other occurred in the lumbar spine with symptoms of long-term spinal pain and radicular pain. Preoperative Technetium bone scan and computed tomography (CT) resulted in exact localization and better operative planning. En bloc excision of tumor is indicated for complete pain relief and full return of spinal mobility.

Adult↗
PubMed1993

Complications of transvaginal ultrasound-directed follicle aspiration: a review of 2670 consecutive procedures.

PURPOSE: Complications following transvaginal ultrasound-directed follicle aspiration are rare, making it difficult to assess their true incidence. During a 4-year prospective study the complications arising from a series of 2670 consecutive procedures were monitored. RESULTS: Vaginal hemorrhage occurred in 229 (8.6%) of the cases, with a significant loss (> 100 ml) in 22 (0.8%). Postoperative pelvic infection occurred in 18 (0.6%) of the cases. Hemorrhage from the ovary with hemoperitoneum formation was seen on two occasions and necessitated emergency laparotomy in one instance. A single case of pelvic haematoma formation from a punctured iliac vessel was also recorded; this settled without intervention. Of the 18 cases with infection, 9 were severe with pelvic abscess formation; microbiological examination of the pus from these cases suggests that the most common route of infection in such cases is probably by direct inoculation of vaginal organisms into the peritoneal cavity by the collecting needle. CONCLUSION: The low incidence of pelvic infection questions the value of using prophylactic antibiotics. No increased risk of infection was demonstrated in cases with preexisting peritoneal damage.

Abscess↗