Search PubMed⌕ Search

Biomedical subjects

Y C Wang

Publications and source records attributed to Y C Wang.

At least 109 records · Page 6Linked to original sources
PubMed1998

Surgical management of intracranial arteriovenous malformation associated with aneurysms.

BACKGROUND: The association of intracranial arteriovenous malformation (AVM) with aneurysm(s) is hazardous, and various forms of treatment have been suggested. Most authors agree that surgery for these combined lesions should be directed toward the symptomatic lesion first. This may be difficult, however, especially when the source of the hemorrhage is unclear. METHODS: Between 1985 and 1996, 12 patients with combined AVM and aneurysm(s) were treated at this institution. Clinical presentations included headache and hemorrhage in all patients, limb weakness in three patients, and seizure in one patient. Hemorrhage types included subarachnoid hemorrhage (SAH), intracerebral hemorrhage (ICH) and intraventricular hemorrhage (IVH). To avoid the intraoperative rupture of aneurysms during resection of the AVM, these were routinely clipped first, followed by total extirpation of the AVM. RESULTS: SAH, ICH and/or IVH simultaneously presented in seven patients (58.3%). According to the surgical findings, bleeding resulted from the aneurysm in 10 patients and AVM in two patients. There was a high incidence of combined lesions in the posterior circulation (67%) in our series. Among the patients with combined lesions in the posterior circulation, half had multiple aneurysms. A total of 21 aneurysms were found in the 12 patients, with five patients harboring multiple aneurysms. Among the 12 patients, 10 had good results. Eight patients received one-stage operations and two received two-stage operations. Two patients died, one of massive rebleeding from multiple giant aneurysms with SAH, IVH and ICH after ventricular drainage, and the other died of massive bleeding during resection of a large AVM. CONCLUSIONS: It is difficult to predict bleeding sources preoperatively by radiologic images. Our experience has led to the belief that the safest approach is to treat the aneurysm before microsurgical resection of the AVM. Most of our patients were surgically treated in one approach and showed good results.

Adult↗
PubMed1998

Microsurgical management of intracranial epidermoid cysts.

BACKGROUND: Intracranial epidermoid cysts are slow-growing congenital neoplasms that usually spread and adhere to critical neurovascular structures along the basal cistern, particularly the cerebellopontine angle (CPA) and parasellar region. Clinical symptoms include trigeminal neuralgia, headache and dizziness, progressive hemiparesis, unstable gait and hemifacial spasm. With the aid of modern imaging techniques, such as computed tomography (CT) and magnetic resonance imaging (MRI), an effective microsurgical approach can be planned preoperatively to completely remove tumors and avoid complications. METHODS: Twenty-six patients with intracranial epidermoid cysts were microsurgically treated between July 1984 and June 1997. Diagnostic procedures included enhanced CT and/or CT cisternography and MRI. All patients underwent microsurgical treatment for tumor removal. RESULTS: Total tumor removal was achieved in 12 patients (46.2%), near-total removal in seven (26.9%), partial removal in six (23.1%) and stereotactic biopsy in one patient (3.8%). Postoperative deterioration of the neurologic condition was found in three patients who required further surgery, aseptic meningitis in four patients and communicating hydrocephalus requiring shunting in three patients. The functional prognoses were excellent in 23 patients (88.5%), good in two patients (7.7%) and fair in one patient (3.8%). Among the 26 patients, three died of pneumonia three, six and nine months after surgery, respectively. CONCLUSIONS: MRI is particularly useful for defining the anatomic limits of tumor tissue and surgical planning. The surgical results were excellent in patients with near-total tumor removal, as well as in patients with total removal. Aggressive surgical tumor removal may result in transient, but significant, cranial nerve palsy and should be avoided. Perioperative administration of steroids and wound protection may be beneficial for preventing the development of postoperative aseptic meningitis and hydrocephalus.

Adult↗
PubMed1998

The effect of sphenopalatine postganglionic neurotomy on the alteration of local cerebral blood flow of normotensive and hypertensive rats in acute cold stress.

The cold season of a year has been reported to have the highest incidence of strokes. Present studies were designed to test whether the parasympathetic denervation plays any role in the regulation of local cerebral blood flow (LCBF) in anesthetized animals exposed to a cold environment. Each species of Wistar-Kyoto rats (WKY) and spontaneously hypertensive rats (SHR) was divided into four groups: sphenopalatine postganglionic neurotomy (SPNx) or a control group at room temperature (20 degrees C) or in a cold environment (5 degrees C), respectively. LCBF in 14 brain structures was measured using the [14C] iodoantipyrine technique and tissue dissecting methods. Our results show that SPNx did not significantly alter physiological parameters and LCBF in WKY and SHR kept at either 20 degrees C or 5 degrees C. However, 30 minutes of cold exposure caused a significant decrease in the core body temperature of both the WKY and SHR groups (P < 0.05, Student's paired t-test) and a significant decrease in LCBF in 3 of 14 brain areas: the temporal cortex (TC), inferior colliculus (IC) and vermis (VER) of both WKY and SHR (P < 0.05, MANOVA). The percentages of decrease were 24% (TC), 12% (IC), 12% (VER) and 19% (TC), 16% (IC), 15% (VER), respectively. Our findings indicate that in a cold environment, the lower LCBFs in some areas of the brain may be related to decreased body temperature. Whether they are related to the higher prevalence of stroke in winter needs further investigation.

Animals↗
PubMed1998

Os odontoideum: a case report and review.

There are five types of odontoid anomalies: os odontoideum, ossiculum terminale, hypoplasia of the odontoid, aplasia of the odontoid base and aplasia of the odontoid. All five anomalies may lead to atlantoaxial instability. Their clinical signs, symptoms and treatments are identical. Only radiographic findings are distinctive. The incidence of odontoid anomalies is uncertain. A 15-year-old boy was hospitalized with progressive numbness of his limbs on the right side for one month. Os odontoideum was confirmed by cervical radiography and magnetic resonance imaging. The lesion was stabilized with autogenous iliac bone fusion and Halifax interlaminar clamp fixation. Treatment with posterior fusion of the C1-C2 vertebrae proved successful. The clinical variations, etiology, diagnosis and surgical management of odontoid anomalies are discussed.

Adolescent↗
PubMed1997

Polymorphisms and intron sequences flanking the alternatively spliced 8-amino-acid exon of gamma2 subunit gene for GABAA receptors.

Gamma-amminobutyric acid (GABA) is a major inhibitory neurotransmitter. Two alternatively spliced forms of the gamma2 subunit of GABAA receptor (gamma2L and gamma2S), which differ by an exon of eight amino acids, show different sensitivities to modulatory effects of ethanol on receptor activities. A 2.7 kb DNA fragment and an 1.7 kb DNA fragment covering respectively the introns upstream and downstream from the 8-amino-acid exon were obtained through PCR-amplification of human genomic DNA using primers derived from cDNA sequences. Total sequencing of these fragments showed a composite 4.2 kb segment containing the 8-amino-acid exon and consensus sequences for RNA splice junctions. Restriction fragment length polymorphisms (RFLP) based on NciI restriction digestion were found among Chinese in Taiwan. This RFLP provides a useful DNA marker for allelic association or linkage analyses of the role of GABAA receptors in predisposition to alcoholism or other neuropsychiatric disorders.

Alternative Splicing↗
PubMed1997

Characterization of proteins binding to the ZII element in the Epstein-Barr virus BZLF1 promoter: transactivation by ATF1.

Previous studies have shown that the ZII element in the BZLF1 promoter (P1) is responsive to TPA and anti-immunoglobulin induction. In this report, we have studied the DNA/protein complexes formed when ZII is used as a binding site. Twelve distinct DNA/protein complexes were seen in mobility shift experiments using Akata cell nuclear extracts and radiolabeled ZII. Eleven of these complexes were also formed when either BJAB or Raji cell nuclear extracts were used in the binding reaction. Six DNA/protein complexes were affected by mutations in the core TGACATCA motif of ZII which abolish responsiveness to TPA, anti-immunoglobulin treatment, and HHV6 transactivation. The relative sizes of the proteins in the DNA/protein complexes were determined by UV crosslinking. Four distinct specific binding proteins affected by core mutations in ZII were identified as ATFa, ATF1, ATF2, and c-jun. Overexpression of ATF1 in cotransfection experiments caused transactivation of the wild-type P1 promoter but had no effect on a promoter containing a mutant ZII element. An ATF1 mutant with a deleted DNA binding domain failed to transactivate P1. Overexpression of c-jun, ATFa, or ATF2 had no effect on the wild-type or mutant P1 promoter. Our results suggest that ATF1 interacts with the ZII element and may be involved in Epstein-Barr virus reactivation.

Activating Transcription Factor 1↗
PubMed1997

Novel point mutation within intron 10 of FMR-1 gene causing fragile X syndrome.

The majority of cases involving fragile X syndrome are due to expansion of a (CGG)n trinucleotide repeat at the 5' untranslated region of the FMR-1 gene. Deletion and intragenic loss of function mutations of the FMR-1 gene also have been reported. Here, we report a C to T point mutation at the 14th nucleotide in intron 10 of the FMR-1 gene in three unrelated fragile X patients. However, the (CGG)n repeat of FMR-1 in those patients does not expand. To determine the effect of this mutation on the patients' FMR-1 transcripts, total RNA from peripheral blood cells was reverse transcribed and amplified by polymerase chain reaction (RT-PCR). Direct and subcloned sequencing of the RT-PCR products revealed that the transcripts from the allele with C to T mutation skip exon 10 entirely, resulting in a joining of exons 9 and 11. Deletion of exon 10 results in frame-shift and premature termination of translation, which removes the highly conserved region that encoding the KH2 and RGG box domains of FMRP. Interestingly, a male of the three patients has another G to A substitution in exon 15. However, the intron 10 mutation is sufficient for development of fragile X syndrome.

Adolescent↗
PubMed1997

Comparison of the APACHE III, APACHE II and Glasgow Coma Scale in acute head injury for prediction of mortality and functional outcome.

OBJECTIVES: This study examines the efficacy of the predicting power for hospital mortality and functional outcome of three different scoring systems for head injury in a neurosurgical intensive care unit (NICU). DESIGN: On the day of admission, data were collected from each patient to compute the Acute Physiology, Age, and Chronic Health Evaluation (APACHE) II and III, and Glasgow Coma Scale (GCS) scores. Hospital mortality was defined as the deaths of patients before discharge from hospital. Early mortality was defined as death before the 14th day after admission. Late mortality was defined as death after the 15th day from admission. Functional outcome was evaluated by Index of Independence in Activities of Daily Living (Index of ADL). SETTING: An 8-bed NICU in a 1270-bed medical center in Taichung Veterans General Hospital. PATIENTS AND PARTICIPANTS: Two hundred non-selected patients with acute head injury were included in our study in a consecutive period of 2 years. Patients less than 14 years old were not included. INTERVENTIONS: None. MEASUREMENTS AND RESULTS: Sensitivity, specificity and correct prediction outcome were measured by the chi-square method in three scoring systems. The Youden index was also obtained. The best cut-off point in each scoring system was determined by the Youden index. The difference in Youden index was calculated by Z score. A difference was also considered if the probability value was less than 0.05. The area under Receiver Operating Characteristic (ROC) curve was computed. Then the area under ROC of each scoring system was compared by Z score. There was statistical significance if p was less than 0.05. For prediction of hospital mortality, the best cut-off points are 55 for APACHE III, 17 for APACHE II and 5 for GCS. The correct prediction outcome is 82.4% in APACHE III, 78.4% in APACHE II and 81.9% in the GCS. The Youden index has best cut-off points at 0.68 for APACHE III 0.59 for APACHE II, and 0.56 for GCS. The area under Receiver Operating Characteristic (ROC) curve is 0.90 in the APACHE III, 0.84 in the APACHE II and 0.86 in the GVS. There are no statistical differences among APACHE III and II, and GCS in terms of correct prediction outcome, Youden Index and the area under the ROC curve. Other physiological variables excluding GCS in APACHE III and II (AP III-GCS, AP II-GCS) have less statistical value in the determination of mortality for acute head injury. For the prediction of late mortality, APACHE III and II yield significantly better results in the area under the ROC curve, correct prediction and Youden index than those of GCS. Other physiological variables (AP III-GCS and AP II-GCS) play an important role in the prediction of late mortality in APACHE scores. For prediction of the functional outcome of surviving patients with acute head injury, the APACHE III yields the best results of correct prediction outcome, Youden index and the area under the ROC curve. CONCLUSION: The APACHE III and II may not replace the role of GCS in cases of acute head injury for hospital or early mortality assessment. But for prediction of the late mortality, the APACHE III and II have better accuracy than GCS. Other physiological variables excluding GCS in the APACHE system play a crucial contribution for late mortality. GCS is simple, less time-consuming and economical for patients with acute head injury for the prediction of hospital and early mortality. The APACHE III provides better prediction for severe morbidity than GCS and APACHE II. Therefore, the APACHE III provides a good assessment not only for hospital and late mortality, but also for functional outcome.

APACHE↗
PubMed1997

Primary intrasellar mixed germ-cell tumor with precocious puberty and diabetes insipidus.

We report an 8-year-old boy with a primary intrasellar mixed germ-cell tumor who underwent the trans-sphenoidal approach for tumor removal. Initially he suffered from diabetes insipidus. Precocious puberty and left abducens nerve palsy were also observed. Elevation of serum testosterone, beta-human chorionic gonadotropin (HCG), and alpha-fetoprotein (AFP) were found on admission. The histological study revealed mixed cellular types of tumor including germinoma, choriocarcinoma, embryonic cell carcinoma, and teratoma. Postoperative radiation to a total of 5000 cGy was performed. Adjuvant chemotherapy was administered before and after radiation. The boy was disease-free during a 6-month follow-up period. Follow-up magnetic resonance imaging showed no presence of tumor. The signs of precocious puberty disappeared, and the diabetes insipidus was easily controlled. The abducens nerve regained normal function. Serum HCG, AFP, and testosterone levels all returned to normal. Serum antidiuretic hormone increased to reach the lower limit of the normal range.

Child↗
PubMed1997

Assessment of neutralizing antibodies elicited by a vaccine (Nakayama) strain of Japanese encephalitis virus in Taiwan.

A total of 368 blood specimens were resampled from a serum collection containing 2914 blood samples which were collected by a random sampling in Taiwan in 1991. The plaque reduction neutralization test was applied to evaluate the neutralizing ability to two strains of Japanese encephalitis viruses, i.e. Nakayama (the present vaccine strain) and JE5 (a Taiwan isolate). The result revealed that antibodies against JE virus were present in each stratified age group. Antibody positive rates were both highest in the group older than 70 years although the lowest rates were located in different groups. In addition, the result showed that the immunogenicity potency of the antibody induced by the vaccine strain did not have a good coverage against JE5. The rate of neutralizing antibodies above the level of protective efficacy of the present vaccine was limited as low as 37.93%. Efficacy of the vaccine used at present was apparently not efficient. Consideration of a more promising vaccine may be necessary.

Adolescent↗
PubMed1997

A nationwide epidemiological study of spinal cord injuries in Taiwan from July 1992 to June 1996.

This prospective epidemiological survey of spinal cord injury (SCI) in Taiwan was carried out by recruiting patients attended by physicians from various medical centers and general hospitals all over Taiwan from July 1992 to June 1996. A total of 6,410 cases of traumatic spinal fracture were registered among which were 1,586 new cases of SCI. The results represented 70% of the scope of SCI in Taiwan. The observed average annual incidence of SCI in Taiwan was 18.8 per million population. The mean age was 46.1 years-old with a plateau distribution for over 20 years and older. Geriatric victims are a major group of SCI in Taiwan. The male to female ratio was 3 to 1. The leading causes of SCI were traffic accidents and accidental falls. Motorcycle collisions accounted for 62% of the traffic accidents, and as most of the motorcycle riders were not helmet users, head injury became the major associated injury of SCI in Taiwan. The effectiveness of the comprehensive care system for SCI patients in Taiwan is relatively good, as reflected by the low rates of complications of SCI, the low mortality rate (6.6%) and the high percentage (67.4%) of SCI patients achieving self-care ultimately at home after rehabilitation. The analysis of person days healthy life loss and quality adjusted survival time revealed that SCI patients in Taiwan required 4 years to cope with the morbidity, and on average, could return to the main stream of life for another 30 years.

Accidental Falls↗
PubMed1997

A nationwide epidemiological study of spinal cord injury in geriatric patients in Taiwan.

This prospective epidemiological survey of spinal cord injury (SCI) in Taiwan was carried out among patients attended by physicians from various medical centers and general hospitals all over Taiwan from July 1992 to June 1996. In all, 1,586 new cases of SCI were registered, representing about 70% of all possible SCI cases in Taiwan. The observed average annual incidence of SCI in Taiwan was 18.8 per million people, whereas it was 47.5 for the geriatric section. The mean age was 46.1 years with a plateau distribution after 20 years and older. Geriatric victims (297 cases, 18.7%, group II) formed a major section of SCI cases in Taiwan. Another group of younger SCI patients (15-64 years old, 1,232 cases, group I) was selected for comparison. The results showed that the male-to-female ratio, pattern of neurological deficits, and causes of injury and death of geriatric SCI patients differed significantly from those of the younger SCI group. Elderly women were exposed to a higher risk of SCI than younger women (M/F ratio 1.7:1). Falls were the leading cause of geriatric SCI, and two thirds of them occurred on level ground. Traffic accidents accounted for a third of SCI cases, half of which involved motorcycle accidents, a fifth of them pedestrians. Quadriplegia and quadriparesis occurred more frequently among elderly cases of SCI than in the younger group and a higher proportion of them died of SCI complications. Two thirds of elderly SCI patients recovered well enough after comprehensive treatment to be able to take care of themselves at home. The government should initiate programs of prevention to reduce the prevalence of geriatric SCI in Taiwan.

Age Factors↗
PubMed1997

Differential development of the enhanced metabolic response during amphetamine sensitization.

Behavioral sensitization elicited by repeated administration of amphetamine does not fully develop until a period after discontinuation of amphetamine, but then persists undiminished for a long time. This experiment investigated the regional metabolic changes in rats pretreated with amphetamine and challenged after different abstinence periods (2, 7 and 28 days), using the 2-[14C]deoxyglucose method. The results demonstrated that chronic amphetamine administration enhanced rates of local cerebral glucose utilization in specific cerebral regions. The magnitude and distribution of effects varied with the abstinence period. A challenge dose of d-amphetamine 2 days after pretreatment was found to have no more, or only mildly elevated, local cerebral glucose utilization compared with that following a single acute dose. In rats challenged at the 7th and 28th day, a supersensitive metabolic response was found in dopaminergic and non-dopaminergic areas. This finding suggested regional differences in the development of sensitization and underscored the importance of an abstinence period in the study of sensitization and amphetamine psychosis.

Amphetamine↗
PubMed1997

Leptomeningeal malignant melanoma arising in neurocutaneous melanocytosis: a case report.

A rare case of histology-proved giant congenital melanocytic nevus (GCMN) with symptomatic leptomeningeal melanocytosis is reported. A 26-year-old man had had a large patch of pigmented nevus over his back and left arm since birth. He had begun to have seizures as well as symptoms and signs of increased intracranial pressure about six months before admission. Serial computed tomography of brain showed hydrocephalus, diffuse leptomeningeal enhancement and multiple well-enhanced, rapid-growing nodules on the surface of the cerebellum and left parietal lobe. Magnetic resonance imaging (MRI) revealed T1 shortening of leptomeninges on precontrast T1 weighted imaging. Skin biopsy was done twice and showed intradermal nevus. Biopsy on one of the intracranial nodules revealed malignant melanoma arising in the melanocytosis. He died one year after the onset of neurologic symptoms. For early diagnosis of neurocutaneous melanocytosis, we suggest 1) MRI, and 2) leptomeningeal biopsy in patients with suspected leptomeningeal malignant melanoma.

Adult↗
PubMed1996

Inhibition of initiation of simian virus 40 DNA replication during acute response of cells irradiated by ultraviolet light.

To study the mechanism by which ultraviolet (UV) light inhibits DNA replication, we examined the effects of UV 254 nm irradiation on the replication of simian virus 40 (SV40) DNA and SV40-based plasmid in monkey cells. The study was designed to determine the relative contributions made by inhibition of replication initiation and chain elongation to the immediate inhibition of DNA replication following UV irradiation. We used two-dimensional neutral-alkaline electrophoresis to examine the behaviour of replication intermediates unambiguously. Kinetic analysis using this technique showed that initiation of replication started to decline at 15 min post-irradiation. When the pulse label incorporated in SV40 replication intermediates before irradiation was chased for 1 h, most of the label was found in mature Form I and II molecules. This indicated that replication elongation took place on damaged template. We also used a transfection technique to show that heavily irradiated plasmids replicated efficiently in unirradiated transfected cells. By the transfection technique, we observed that UV irradiation of host cells dose-dependently inhibited replication of transfected non-irradiated plasmids, suggesting that the inhibition of DNA replication is due to a global change in cellular physiology induced by UV. This change was also apparent from poor staining of the chromatin by fluorescent-DNA-binding dyes immediately after UV irradiation of intact cells. We conclude that a significant fraction of chain elongation proceeds on damaged templates and DNA replication during the acute response of cells irradiated with UV is mainly controlled by the inhibition of replication initiation.

Animals↗