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Biomedical subjects

T T Wong

Publications and source records attributed to T T Wong.

At least 37 records · Page 2Linked to original sources

Postcallosotomy seizure outcome in hemiconvulsion-hemiatrophy-epilepsy syndrome.

Recently, three patients with hemiconvulsion-hemiplegia-epilepsy syndrome who underwent callosotomy were monitored for more than four years. All patients had atrophy of the right brain hemisphere with left hemiparesis and seizures. Two cases were probably the result of traumatic intracranial hemorrhage and one was due to an unknown cause. Wada tests were done in cases 1 and 2, which showed spared motor function of the atrophic hemisphere, supporting the choice of callosotomy instead of hemispherectomy. Patient 1 had atypical absence seizures and asymmetric generalized tonic seizures before surgery, the latter of which decreased by about 60% after callosotomy. Patient 2 had simple partial seizures of the motor type and complex partial seizures, the latter of which were also induced by touch (somatosensory-induced reflex epilepsy). This patient's complex partial seizures disappeared completely, but the simple partial seizures remained unchanged. Patient 3 had generalized tonic seizures, simple partial seizures of the sensory type and complex partial seizures. After surgery, the frequency of the generalized tonic seizures decreased more than 90%. The simple partial seizures of the sensory type remained unchanged. There were two new types of seizures after surgery, simple partial seizures of the motor type and brief generalized myoclonic jerks. All patients had significant reductions in numbers of seizures of more than 50%.

Adolescent↗

Pilocytic astrocytoma of the posterior fossa: a follow-up study in 15 patients.

BACKGROUND: The extent of resection in pilocytic astrocytoma of the posterior fossa remains undefined, as the problem of hydrocephalus has not yet been solved. We retrospectively reviewed the data from 15 patients with a pilocytic astrocytoma of the posterior fossa to evaluate the impact of surgical technique, in terms of resection extent, by serial magnetic resonance imaging (MRI) examinations. In addition, the issue of hydrocephalus was considered and related to the different treatment modalities. METHODS: Macroscopic, gross, total resection of the tumor was performed in all 15 patients. Follow-up was obtained in 14 patients for a period ranging between 11 and 119 months (median, 41.5 months). The ages of patients ranged from two to 13 years (mean, 7 +/- 3 years). All patients underwent serial MRI examinations in the first month, every six months for the first two years and then yearly. RESULTS: Outcome was good in 12 patients who had no neurologic deficit and fair in two patients who were slightly handicapped but had an independent life. There were four patients with an abnormally persistent enhancement on MRI, with a median follow-up of 30 months. One of these patients had progressively increasing size of the enhancement. Three of them had the same size of enhancement during the follow-up period. The MRI findings showed residual tumors in four patients. One of them had tumor regrowth one year after surgery. There were 11 cases with pilocytic astrocytoma and hydrocephalus. Five patients were treated with tumor removal and external CSF drainage. Six patients underwent tumor removal only, without perioperative cerebrospinal fluid (CSF) drainage. Only one patient had a permanent ventriculoperitoneal shunt. CONCLUSIONS: Our study illustrated that the extent of tumor resection of pilocytic astrocytoma can be defined by postoperative serial MRI examinations. Long-term follow-up with MRI seems mandatory in cases with abnormal enhancement. Hydrocephalus is a common finding in patients with a pilocytic astrocytoma. A permanent ventriculoperitoneal shunt is required only in patients with postoperative hydrocephalus.

Adolescent↗

Interactive navigation and bronchial tube tracking in virtual bronchoscopy.

An interactive virtual environment for simulation of bronchoscopy is developed. Medical doctor can safely plan their surgical bronchoscopy using the virtual environment without any invasive diagnosis which may risk the patient's health. The 3D pen input device of the system allows the doctor to navigate and visualize the bronchial tree of the patient naturally and interactively. To navigate the patient's bronchial tree, a vessel tracking process is required. While manual tracking is tedious and labor-intensive, fully automatic tracking may not be reliable. We propose a semi-automatic tracking technique called Intelligent Path Tracker which provides automation and enough user control during the vessel tracking. To support an interactive frame rate, we also introduce a new volume rendering acceleration technique, named as IsoRegion Leaping. The volume rendering is further accelerated by distributed rendering on a TCP/IP-based network of low-cost PCs. With these approaches, a 256 x 256 x 256 volume data of human lung, can be navigated and visualized at a frame rate of over 10 Hz in our virtual bronchoscopy system.

Bronchoscopy↗

Pediatric intracranial germinoma treated with chemotherapy alone.

BACKGROUND: Pediatric intracranial germinoma treated with radiotherapy is considered a standard treatment, but may cause significant delayed damage to the central nervous system. Chemotherapy has been shown to be effective for the treatment of an intracranial germinoma. In the past 10 years, we treated 11 cases of primary intracranial germinoma with chemotherapy alone. The purpose of this retrospective study is to review the clinical outcome of these patients. METHODS: Eleven children with newly diagnosed, previously untreated primary intracranial germinomas were treated with six courses of chemotherapy (vinblastine bleomycin, cisplatin and etoposide, VBPE). The response to chemotherapy, relapses and outcomes are reviewed and evaluated. RESULTS: All 11 assessable children achieved a complete response and are alive, with a median follow-up of 61 months. Five patients with tumors located in the midline position of the brain, including pineal, sellar, suprasellar and hypothalamic areas, had no relapse. Six patients had relapses, and all of them achieved a second complete remission after salvage focal radiotherapy. The time of onset of relapse was from nine to 24 months after chemotherapy, with an average of 16.8 months. CONCLUSIONS: VBPE chemotherapy was effective for treating newly diagnosed intracranial germinomas. Although a high rate of relapse (6/11) was observed, all of these patients survived with first or second complete remissions. It was beneficial for five children that focal radiation was eliminated and delayed post-irradiation neurologic sequelae were avoided.

Adolescent↗

MIB-1 labeling index in nonpilocytic astrocytoma of childhood: a study of 101 cases.

BACKGROUND: The prognosis of pediatric patients with nonpilocytic astrocytoma, and in particular those with anaplastic astrocytoma, is somewhat unpredictable. This study used MIB-1 monoclonal antibody, a proliferative marker that can be used in formalin fixed paraffin embedded tissues, to study nonpilocytic pediatric astrocytoma. METHODS: Astrocytoma, anaplastic astrocytoma, and glioblastoma specimens excised from a total of 101 pediatric patients during the period from January 1975 to September 1996 were retrieved from the authors' surgical pathology file. Histologic grading of the specimens was performed based on a modified Ringertz system. The proliferative potential of the tumors was estimated by using the MIB-1 labeling index (LI), which was evaluated with morphologic grades of tumors and survival of the patients. RESULTS: Of the 101 patients, 34 had astrocytoma, 33 had anaplastic astrocytoma, and 34 had glioblastoma. Their mean survival times were 165.2+/-14.9 months (mean+/-standard error; SE), 46.1+/-9.9 months, and 21.8+/-5.6 months, respectively. The mean MIB-1 LI of different tumor grades were as follows: astrocytoma, 3.9+/-4.3 (mean+/-standard deviation; range, 0.0-21.6); anaplastic astrocytoma, 24.3+/-15.6 (range, 1.7-62.8); and glioblastoma, 35.9+/-16.4 (range, 7.36-63.3). The mean survival of the entire group of patients with LIs < or = 11 was 173.2+/-12.2 months (mean+/-SE), and the mean survival of those with LIs > 11 was 20.3+/-4.1 months. The survival of anaplastic astrocytoma patients with LIs < or = 11 was similar to that of astrocytoma patients, whereas the survival of anaplastic astrocytoma patients with LI > 11 was similar to that of patients with glioblastoma. CONCLUSIONS: The results of the current study show that histopathologic grading can predict the outcome for patients with astrocytomas and glioblastomas, whereas MIB-1 LI can separate better and worse prognostic groups in patients with anaplastic astrocytoma.

Adolescent↗

Prognostic factors and therapeutic options of radiotherapy in pediatric brain stem gliomas.

BACKGROUND: A retrospective analysis was made to clarify the relationship between prognosis, radiation dose and survival of brain stem gliomas. METHODS: From 1983 to 1995, 22 children with brain stem tumors were treated by radiotherapy in the Veterans General Hospital-Taipei. Twelve patients had pathology proof and the remainder were diagnosed by computerized tomography and/or magnetic resonance imaging. Seven patients had postoperative radiotherapy. Fifteen patients had radiotherapy as primary management, five of whom had adjuvant chemotherapy. All patients received 4000-7060 cGy, either in conventional daily or hyperfractionated twice daily radiotherapy. Survival from date of diagnosis was calculated by the Kaplan-Meier method. Univariate analyses and multivariate analyses were calculated by the log rank test and the Cox proportional hazard model, respectively. RESULTS: Most patients showed improvement following treatment. The overall 2-year survival rate was 55.5% with a median survival of 27.1 months. Two-year survival for patients with primary management of operation and radiotherapy (n = 7), radiotherapy alone (n = 10) and radiotherapy with adjuvant chemotherapy (n = 5) were 66.7, 50 and 53.3%, respectively. In univariate analysis, the study revealed that the growth pattern of tumors and the simultaneous presence of cranial neuropathy and long tract sign were significant prognostic factors (P = 0.017 and 0.036). A trend of better outcome with radiation dose > 6600 cGy and the hyperfractionation scheme was also noted in our study (P = 0.0573 and 0.0615). However, only the hyperfractionation scheme was also noted in our study (P = 0.0573 and 0.0615). However, only the hyperfractionation scheme showed significance in multivariate analyses (P = 0.0355). Survival was not significantly affected by age, gender or method of diagnosis. CONCLUSION: Radiotherapy appears to be an effective treatment modality of brain stem tumors. Patients with both cranial neuropathy and long tract signs had a poorer outcome. Hyperfractionated radiotherapy may give better local control and lead to better survival.

Brain Neoplasms↗

Neuropsychological sequelae after treatment for medulloblastoma in childhood--the Taiwan experience.

The purpose of this study was to investigate the functional independence, intellectual performance and academic achievement of children treated for medulloblastoma at the Veterans General Hospital-Taipei. Adverse factors that it was thought would result in significant intellectual impairment were also studied. Nineteen patients with medulloblastoma located over the posterior fossa were enrolled in this study. Their mean age at tumor removal was 6.16 +/- 3.30 (range 2-14) years. Mean full intelligent quotient (FIQ) was 86.00 +/- 22.66, performance intelligent quotient (PIQ) was 85.29 +/- 21.23, and verbal intelligent quotient (VIQ) was 90.50 +/- 23.50. In 11 cases academic achievement at school was poor. Sixteen patients received radiation therapy after tumor removal. Significant negative correlations were noted between IQ and whole-brain irradiation dose (r = -0.72) and between IQ and years after radiation therapy (r = -0.63). The results indicate a need for ongoing attention and intervention to prevent, remedy or minimize deficits produced by the tumor itself and by the cancer treatment.

Achievement↗

Primary cerebellar extramedullary myeloid cell tumor mimicking oligodendroglioma.

Extramedullary myeloid cell tumors (EMCTs) are tumors consisting of immature cells of the myeloid series that occur outside the bone marrow. Most of them are associated with acute myelogenous leukemia or other myeloproliferative disorders, and a small number occur as primary lesions, i.e., are not associated with hematological disorders. Occurrence inside the cranium is rare, and there has been only one case of primary EMCT involving the cerebellum reported in the literature. The case we report here is a blastic EMCT occurring in the cerebellum of a 3-year-old boy who had no signs of leukemia or any hematological disorder throughout the entire course. The cerebellar tumor was at first misdiagnosed as an "oligodendroglioma" because of the uniformity and "fried egg" artifact of the tumor cells. The tumor disappeared during chemotherapy consisting of 12 treatments. However, it recurred and metastasized to the cerebrospinal fluid (CSF) shortly after the therapy was completed. A diagnosis of EMCT was suspected because of the presence of immature myeloid cells in the CSF, and was confirmed by anti-myeloperoxidase and anti-lysozyme immunoreactivity of the cerebellar tumor. The patient succumbed 1 year and 3 months after the first presentation of the disease.

Cerebellar Neoplasms↗

Interaction of 4-tert-butyl-[3-(2-chloroethyl) ureido] benzene with phosphatidylcholine bilayers: a differential scanning calorimetry and infrared spectroscopy study.

We have investigated the interaction between a new antineoplastic drug, 4-tert-butyl-[3-(2-chloroethyl)ureido] benzene (tBCEU), and distearoylphosphatidylcholine bilayers using differential scanning calorimetry, Fourier transform infrared spectroscopy (FT-IR), and high-pressure infrared spectroscopy. The results obtained with the three different techniques indicate that the drug incorporates in the lipid bilayer. More specifically, the incorporation of the tBCEU results in a decrease in the phase transition temperature of the lipid and in an increase in the amount of gauche conformers in the liquid-crystalline phase. In the gel phase, high-pressure FT-IR results indicate that the incorporation of tBCEU decreases the acyl chain packing. In addition, the results suggest the presence of hydrogen bonding between the lipid carbonyl group and a hydrogen bond donor in the tBCEU molecule. A possible candidate for this donor is the NH group adjacent to the phenyl ring. A model is proposed for the incorporation of tBCEU in lipid bilayers, with the hydrophobic portion of the drug intercalated between the lipid bilayers and the hydrophilic region located close to the interfacial region of the bilayer.

Antineoplastic Agents↗

A method of enlarging the opening of the third ventricular floor for flexible endoscopic third ventriculostomy.

In the Pediatric Neurosurgical Service of the Veterans General Hospital, Taipei, flexible endoscopic III ventriculostomy has been applied in children with noncommunicating hydrocephalus and periaqueductal/pineal tumor. We modified the technique to allow enlargement of the opening of the III ventricular floor. The use of an Atlas Wire Stone Extractor for this purpose is described.

Biopsy↗

Quality of life and life satisfaction in families after a child has undergone corpus callostomy.

Epilepsy is a chronic neurological condition which can have a detrimen tal effect on patients' quality of life (QOL). We evaluated the overall satisfaction with QOL and changes in QOL in 25 families with children who had undergone corpus callostomy for severe epilepsy. The mean age of seizure onset was 3.4 years, and the mean period from seizure onset to operation was 5.2 years. Mean follow-up was 19.3 months. Twenty of 22 patients had various degrees of mental retardation. Mean reduction in severity of seizure activity was 64%. Nineteen of 25 (76%) parents were satisfied with the surgical result. Eighteen of 25 parents (72%) described a good level of satisfaction with their families QOL after callostomy. Reduction in severity of seizure activity was significantly correlated with how successful families considered the surgery to be and how satisfied they were with their QOL (r = 0.72 and 0.77, respectively). Life domains showing one greatest improvement after callostomy included level of self-care, family life, and school performance. Improvements in level of self-care, family life, and school performance were associated with higher levels of life satisfaction (r = 0.69, 0.60, and 0.59, respectively). Hyperactivity, attention span, and social skills improved significantly in 11 patients after surgery. Callostomy did not improve mental performance. We conclude that improved seizure control after callostomy is also associated with improved QOL.

Achievement↗

Combination chemotherapy with vinblastine, bleomycin, cisplatin, and etoposide (VBPE) in children with primary intracranial germ cell tumors.

We have treated 13 children with primary intracranial germ cell tumors with the combination of vinblastine, bleomycin, cisplatin, and etoposide, the so-called VBPE regimen in the past seven years at one institution. The clinical diagnosis of these children were: three germinomas, seven non-germinomatous germ cell tumors, and three recurrent non-germinomatous germ cell tumors without previous chemotherapy. Of this group, three germinomas and three non-germinomatous germ cell tumors were treated primarily with VBPE plus radiotherapy. All of them responded completely, and were free of tumor. Primary VBPE regimen without radiotherapy was used in another four non-germinomatous germ cell tumors. After six courses of VBPE regimen, only one of the four patients achieved complete response for 30 months. VBPE regimen was used as salvage chemotherapy in three recurrent non-germinomatous germ cell tumors without previous chemotherapy. After six courses of VBPE regimen, two had complete response for 58+ months and 78+ months respectively. We concluded that in newly-diagnosed intracranial non-germinomatous germ cell tumors, the combination of chemotherapy VBPE regimen and radiotherapy led to good results. Primary chemotherapy with VBPE alone was not adequate for the treatment of non-germinomatous germ cell tumors. However, VBPE regimen might be one of the salvage therapies for recurrent germ cell tumors without chemotherapy before relapse.

Adolescent↗

Familial neurofibromatosis 1 with germinoma involving the basal ganglion and thalamus.

Intracranial germinoma associated with neurofibromatosis 1 (NF-1) has never been documented previously. We report a case of familial NF-1 with a germinoma involving the right basal ganglion and thalamus. A 12-year-old boy presented with multiple café-au-lait spots and a family history of neurofibromatosis in his mother, one of two siblings, and his maternal grandfather. His intracranial lesion was subtotally resected. Histologically, it was a pure germinoma. Serum alpha-feto protein and beta-human chorionic gonadotropin levels were within the normal range. Postoperative myelographic examination and cerebrospinal fluid cytology study showed no evidence of subarachnoid seeding. The patient received postoperative combination chemotherapy resulting in complete response and clearance of the residual tumor. Although this finding of an intracranial germinoma in a patient with familial NF-1 may be coincident, it is suggestive of a potential genetic predisposition. Longitudinal evaluation for the possibility of neoplasm, especially germ cell tumor, in basal ganglion lesions in NF-1 patients is necessary.

Basal Ganglia↗

Audit of basal cell carcinoma in Princess Margaret Hospital, Hong Kong: usefulness of frozen section examination in surgical treatment.

A retrospective study was undertaken of 64 Chinese patients with primary (previously untreated) basal cell carcinoma (BCC) surgically treated by the plastic and reconstructive surgery team at the Princess Margaret Hospital, Hong Kong, from January 1988 to March 1994. Sixty-three (98%) were in the head and neck region, half on the nose. It was equally common in men (mean age 69 years) and women (mean age 67). Two women (3%) were younger than 35. The rate of complete excision increased after the introduction of frozen section examination. A complete excision rate of 89% (n = 57) was achieved by 1994. We conclude that frozen section examination should be done routinely in patients having BCC excised.

Adult↗

Lumboperitoneal shunt complicated with chronic tonsillar herniation: a case report.

Lumbopritoneal shunt (L-P shunt) has been widely accepted as a treatment for communicating hydrocephalus. The technique offers many advantages such as easy insertion, a low infection rate, a reduced incidence of brain damage, et centera. Despite these advantages, there are also some associated complications, such as tonsillar herniation. This complication rarely occurs, but, when it does, it develops gradually. This report concerns an eight-year-old girl, who had received L-P shunt at the age of 20 days; she then developed tonsillar herniation, requiring operative decompression, eight years later. This case illustrates the necessity for carefully follow up patients who have undergone the L-P shunt procedure.

Cerebellar Diseases↗