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Biomedical subjects

S T Lee

Publications and source records attributed to S T Lee.

At least 163 records · Page 9Linked to original sources
PubMed1996

Pneumocephalus due to nasopharyngeal carcinoma: case report.

A 55-year-old man with recurrent nasopharyngeal carcinoma presented with intractable headaches and intermittent rhinorrhoea for 2 weeks. CT showed severe destruction of the skull base by the tumour. The headache persisted despite intraventricular morphine. On the 29th hospital day, sudden onset of neurological deterioration led to coma, and CT revealed tension pneumocephalus due to nasopharyngeal carcinoma breaking through the skull base. The literature on pneumocephalus is reviewed and the aetiology discussed.

Cerebrospinal Fluid Rhinorrhea↗
PubMed1996

Mutations of the tyrosinase gene in three Korean patients with type I oculocutaneous albinism.

Oculocutaneous albinism (OCA) is an inherited disorder of the melanin pigmentary system, characterized by a decrease or an absence of melanin in the skin, hair, and eyes. Type I (tyrosinase-deficient) OCA results from mutations of the tyrosinase (TYR) gene encoding tyrosinase, the enzyme that catalyzes at least the first two steps of melanin biosynthesis. We have analyzed the TYR gene in three Korean patients with severe type I OCA. Two patients were compound heterozygotes for the Arg (CGG) to Gln (CAG) mutation at position 77 and a C insertion mutation at position 310. The other was a compound heterozygote for a C insertion mutation at position 310 and the Asp (GAT) to Asn (AAT) mutation at position 383. These mutations were easily detected by restriction enzyme digestion or by SSCP analysis. Such methods of mutation analysis thus provide a basis for a screening system for the TYR gene mutations in Korean patients with type I OCA.

Albinism, Oculocutaneous↗
PubMed1996

Fluctuating hemiparesis caused by a quadrigeminal arachnoid cyst: case report.

A 42-year-old woman presented with intermittent hemiparesis mimicking a reversible ischemic neurologic deficit. Magnetic resonance imaging (MRI) demonstrated a compression of the left side of the midbrain by a quadrigeminal arachnoid cyst without hydrocephalus. After the cystic wall was widely excised under operating microscope, the patient made a good recovery and remained well at a follow-up of 18 months. The absence of hydrocephalus in a symptomatic patient with a quadrigeminal cyst was exceptional, which might result from the early diagnosis with MRI. The use of microsurgical technique made it possible to excise the cystic wall widely and omit a shunting procedure.

Adult↗
PubMed1996

Characterization of the human full-length PTK7 cDNA encoding a receptor protein tyrosine kinase-like molecule closely related to chick KLG.

A 220-bp fragment of PTK7 cDNA was previously cloned from normal human melanocyte RNAs by means of the reverse transcription-polymerase chain reaction [Lee, S.-T., Strunk, K.M., and Spritz, R.A. (1993) Oncogene 8, 3403-3410]. We now report the cloning of the human full-length PTK7 cDNA and its characterization. The 1,070 amino acid PTK7 polypeptide deduced from the cDNA sequence constitutes receptor protein tyrosine kinase (RPTK), but has several unusual residues in some of the highly conserved tyrosine kinase motifs. PTK7 mRNA was expressed at the highest level in a human erythroleukemia cell line among tested samples, and at relatively high levels in liver, lung, pancreas, kidney, placenta, and melanocytes. Human PTK7 is 72% identical to chick KLG, suggesting that PTK7 is homologous or possibly orthologous to chick KLG, and that these represent a new subfamily of RPTKs.

Amino Acid Sequence↗
PubMed1996

C1-C2 fracture-dislocations in children and adolescents.

OBJECTIVE: C1-C2 is the predominant level of cervical spine injuries in children and adolescents. Either a fracture of the dens or atlantoaxial dislocation (AAD) without fracture of the dens can occur. We present a number of cases to compare their clinical presentations and discuss the preferred method of treatment. MATERIAL AND METHODS: There were 12 cases of type II odontoid fracture and 10 cases of AAD without fracture over a 13-year period. There was a male predominance and traffic collisions were the major cause of injury. Two thirds of the dens fractures were in children over 13 years of age and seven out of ten dislocations without fracture were under 13 years of age. Eight patients with fractured dens suffered from spinal cord injuries but six of those with dislocations were neurologically intact. Two patients of fractured dens and one with AAD presented with chronic myelopathies because of undetected injuries. RESULTS: Three patients expired because of irreversible respiratory failure. Most of the fractured dens achieved bony union after 3 months of halo-vest immobilization but those patients with AAD without fracture usually needed a fusion procedure. Transoral decompression was performed in two cases of dens fracture malunion. All of the survivors of the dens fracture returned to normal or independent daily living. Six of the AAD patients returned to normal, one had a mild neural deficit, and one had persistent spastic quadriparesis. CONCLUSIONS: There is a higher incidence of atlantoaxial dislocation without fracture in children under 13 years of age and a higher incidence of dens fractures in those over 13 years of age. Those with fractures of the dens are more likely to present with evidence of neural injury while those with AAD are more likely to be neurologically intact; however, a correct diagnosis and proper management are mandatory to prevent chronic myelopathy. Halo-vest immobilization is sufficient for most fractures of the dens in children, with AAD usually requiring a fusion.

Adolescent↗
PubMed1996

Fractured odontoid: the management of delayed neurological symptoms.

Undiagnosed and untreated odontoid fractures are relatively common in developing countries where treatment for minor injuries is not considered. As a result, patients frequently present with neurological deterioration secondary to delayed odontoid dislocation. Fifty-one consecutive patients with this problem were entered into a management protocol and reviewed for this report. After diagnosis, reducibility was analyzed by extension films, and all patients who could not be reduced were initially managed in cranial long traction. Thirty-seven were reduced spontaneously or by traction alone, and 12 required transoral decompression. All underwent posterior C1-C2 fusion. Postoperatively, all were treated in external orthoses. The neurological recovery was excellent in 34 patients. Seven patients could function but had some disability, three patients had disabling spasticity, and three remained bedridden. Four deaths occurred as a result of respirator-dependent patients being taken home for social and financial reasons. As a result of this case-controlled study, we recommend that the treatment protocol first analyze reducibility by extension x-rays and then try traction for as long as 14 days to attempt reduction in patients who did not reduce in extension. Failure of reduction is indication for transoral decompression, and all patients require C1-C2 fusion. The neurological recovery is related to initial impairement but can be satisfactory in > 75% of patients.

Adolescent↗
PubMed1996

Genomic organization and sequence of D12S53E (Pmel 17), the human homologue of the mouse silver (si) locus.

We have determined the DNA sequence and genomic organization of D12S53E (Pmel 17), the human homologue of the mouse silver (si) locus. D12S53E encodes a melanosomal matrix protein whose expression is closely correlated with cellular melanin content and which is a frequent melanoma tumor antigen recognized by cytotoxic T lymphocytes. D12S53E is a likely candidate gene for some cases of human oculocutaneous albinism not associated with known albinism loci.

Alternative Splicing↗
PubMed1996

Postoperative ambulation of patients with intraspinal neurilemomas and meningiomas.

Factors affecting the postoperative ambulatory state of patients with intraspinal neurilemomas and meningiomas were evaluated in 92 patients who underwent surgery at the Chang Gung Memoriam Hospital. The patients' records were reviewed retrospectively and leg power grading was noted (Medical Research Council of Great Britain grading system, zero to five). Of the 89 patients with a preoperative leg power of 1 or better, 87 could walk with or without aids shortly after surgery. The remaining three patients, with a preoperative leg power of zero, were all wheelchair-bound postoperatively. The presence of sensory deficits and sphincter incontinence did not correlates with a poor postoperative ambulatory state, provided the preoperative leg power was above zero. The average period between the onset of the earliest symptoms and the establishment of the diagnosis was 68 weeks for patients with intraspinal neurilemomas and 71 weeks for those with meningiomas. Surgical for patients with neurilemomas were as good as those with meningiomas. Patients with multiple spinal neurilemomas did not fare any worse after surgery.

Chi-Square Distribution↗
PubMed1996

Vancomycin-resistant Enterococcus in the Singapore National Burns Centre: a case report.

Vancomycin-resistant Enterococcus (VRE) is becoming an important cause of nosocomial infections. An outbreak of VRE in a burns unit, if it ever occurs, will be a catastrophe as vancomycin-resistance can potentially be transferred to other organisms like methicillin-resistant Staphylococcus aureus. We report a case of VRE in our burns centre in which it was detected and the patient isolated from other patients early. Measures to control the occurrence of VRE include the restriction of the use of vancomycin and the practice of other established infection-control measures.

Accidents, Home↗
PubMed1996

Cystic meningioma in children: a case report.

The case of a child with a cystic meningioma is reported, along with a review of 25 cases from the literature. Cystic change is more common in infants in the first year of life. Eleven of the 26 cystic tumors were in infants. More than half of the cystic meningiomas in adults are meningotheliomatous, while that is the least common subtype in children. Complete removal of the cyst wall is necessary in the intratumoral type to prevent recurrence.

Child↗
PubMed1996

Ventrolateral thalamotomy for dyskinesia following levodopa therapy of Parkinson's disease.

We report a 65-year-old male parkinsonian patient who developed dominantly unilateral choreic movements over his right-side extremities after a daily dosage of up to 1,000 mg of carbidopa-levodopa (carbidopa 200 mg, levodopa 800 mg) for 12 years. The disabling choreic movement appeared as a pattern of peak-dose dyskinesia and was so severe that he was unable to sit or stand still to suppress the involuntary movements. It started about 20 minutes after each dose of levodopa and lasted for about 2 hours. Although the dyskinesia could be reduced by decreasing the levodopa dosage, he could not tolerate the severe parkinsonian disabilities. The dyskinesia did not respond to baclofen, diazepam or clozapine. The chorea was successfully treated surgically using stereotactic left ventrolateral thalamotomy. This is an important treatment for patients with intractable dyskinesia after prolonged levodopa therapy.

Humans↗
PubMed1995

Identification of a very early promoter of insect Hz-1 virus using a novel dual-expression shuttle vector.

Very early promoters of viruses control the proper cascade expression of viral genes and are essential for completion of virus life cycles. These promoters are usually rare and weak and do not encode structural proteins. As a result, they are difficult to identify. In order to identify and clone the very early promoters of a large eukaryotic DNA virus, the Hz-1 virus, a novel cloning strategy was applied. This strategy is based on a dual-expression shuttle vector containing a promoter-less lacZ gene. Insertion of eukaryotic promoters upstream permits the efficient expression of LacZ in bacteria cells. The function of the putative promoters was then confirmed by their proper expression in insect cells. The first two productive infection-specific promoters of Hz-1 virus, contained within the shuttle vectors pTSV-2-129 and pTSV-2-49, were cloned from the HindIII-K and HindIII-A fragments of the Hz-1 viral genome, respectively. By primer extension analysis, an immediate and constitutive expression of the promoter in clone pTSV-2-129 was detected after viral infection. Identification of the productive infection-specific promoters has laid down important groundwork for future studies on the molecular mechanism of the transcriptional switch between productive and persistent infections of Hz-1 virus.

Alcohol Dehydrogenase↗
PubMed1995

Organization and sequence of the human P gene and identification of a new family of transport proteins.

We have determined the structure, nucleotide sequence, and polymorphisms of the human P gene. Mutations of the P gene result in type II oculocutaneous albinism (OCA2) in humans and pink-eyed dilution (p) in mice. We find that the human P gene is quite large, consisting of 25 exons spanning 250 to 600 kb in chromosome segment 15q11-q13. The P polypeptide appears to define a novel family of small molecule transporters and may be involved in transport of tyrosine, the precursor to melanin synthesis, within the melanocyte. These results provide the basis for analyses of patients with OCA2 and may point toward eventual pharmacologic treatment of this and related disorders of pigmentation.

Albinism, Oculocutaneous↗
PubMed1995

In vitro metabolism of testosterone by gonads of the grouper (Epinephelus tauvina) before and after sex inversion with 17 alpha-methyltestosterone.

The steroidogenic potential of gonadal tissues of the protogynous grouper (Epinephelus tauvina) was examined before and after sex inversion with 17 alpha-methyltestosterone. Incubations of gonadal tissues of the fish with [3H]testosterone resulted in the biosynthesis of 5 beta-androstane-3 beta, 17 beta-diol and 5 beta-dihydrotestosterone as the only metabolites in the female phase. Although the production of these 5 beta-reduced androgens persisted in the male phase, there was a shift toward the production of 11 beta-hydroxytestosterone and 11-ketotestosterone as major metabolites.

Androstane-3,17-diol↗
PubMed1995

Early seizures after moderate closed head injury.

The incidence and clinical significance was studied in 2574 closed head injury patients, each of them having a Glasgow Coma Scale (GCS) 9 to 12 after trauma. All patients underwent computerized tomography (CT) after being admitted to the emergency service. One hundred and six patients (4.1%) experienced seizures within 1 week after head injury; 46 of these (1.8% of the series) had seizures within 24 hours after trauma. There was no statistically significant difference between the early seizure and seizure free group of patients in gender, age and GCS with the exception of cause of injury (p < 0.01). The incidence of intracerebral parenchymal damage was found to be higher with seizures developing between day 2 and day 7 (80%) than those with seizures developing within 24 hours (54.3%). Analysing the data revealed that early posttraumatic seizures were not related to the presence of intracerebral parenchymal damage on CT scan. The occurrence of early seizures did not affect the mortality and outcome of moderate closed head injury patients.

Adult↗
PubMed1995

Relative risk of deterioration after mild closed head injury.

In this prospective study, a series of 1812 consecutive mild head injured adult patients who visited the hospital emergency department were assessed. Twenty-eight patients (1.5%) deteriorated after head injury; 23 of these (1.3% of the series) required surgical intervention. Five patients (0.3%) deteriorated due to non-surgical causes [post-traumatic seizure 2, syndrome of inappropriate secretion of antidiuretic hormone (SIADH) 3]. Most of the deterioration occurred within the first 24 hours (57%). Post-traumatic headache was found in 280 patients (15.5%) and 84 patients (4.6%) suffered post-traumatic vomiting. The relative risk is calculated. Age over 60, presence of drowsiness, focal motor weakness, post-traumatic headache and vomiting has increased risk of deterioration (p < 0.001). This study suggests that post-traumatic headache and vomiting deserve more clinical attention rather than being considered as post-traumatic syndrome only.

Adolescent↗
PubMed1995

Using Fyrite to monitor incubator carbon dioxide levels.

PURPOSE: The Fyrite analyzer (Bacharach, Incorporated) was evaluated to ascertain whether it would perform within the range specified by the manufacturer (+/- 0.5%). Fyrite analyzer samples were compared to control samples obtained using an infrared CO2 monitor (Ohmeda, Model Number 5200). METHODS: Ten Fyrite analyzer measurements from each of three incubators were obtained using two different analyzers by three investigators for a total of 60 measurements per investigator. Twenty control measurements for each of the three incubators were obtained using an infrared monitor calibrated at the 5.0% CO2 level. RESULTS: Fyrite analyzer values fell outside of an acceptable range (Control mean CO2 +/- 0.5%) for 7 of 60 (11.7%) observations for Incubator 1 and 4 of 60 (6.7%) observations for Incubator 2. (Incubator 3 had no values outside the range.) The Fyrite analyzers were significantly different from each other (P = 0.002). The three investigators (I) differed significantly from the control (I1 and I3, P < 0.001; I2, P = 0.02) as well as from each other (I1 vs I2, P < 0.001; I1 vs I3, P < 0.001; I2 vs I3, P < 0.016). CONCLUSIONS: Use of an infrared monitor for incubator calibration and monthly CO2 checks in concert with daily use of the Fyrite as a monitoring tool only is the better method.

Calibration↗