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Biomedical subjects

L S Chin

Publications and source records attributed to L S Chin.

At least 55 records · Page 3Linked to original sources
PubMed1995

Surgical correction of muscular torticollis in older children.

BACKGROUND: Children with muscular torticollis treated before the age of 1 year respond well to conservative treatment. Surgical correction is indicated only in resistant cases. Nevertheless, there is still controversy about the results and the type of operation in the management of neglected older children. METHODS: Seventeen patients, at a mean age of 9 years and 5 months, with muscular torticollis were surgically treated between 1986 to 1991. The average follow-up period was 3 years and 4 months. months. Combined approach with open tenotomy at mastoid and clavicular level was the choice of procedure. The outcome for these older children and young adults were evaluated with function and cosmesis. RESULTS: Our results showed that the best results can be expected in children before 12 years of age. Late releases give acceptable results, although facial asymmetry and some residual upper dorsal scoliosis remain. Adequate surgical release and intensive postoperative physical therapy are the keystones to a good result. CONCLUSIONS: Surgical correction of muscular torticollis in the older children is of benefit for functional and cosmetic recovery, but facial asymmetry is irreversible after 12 years of age.

Adolescent↗
PubMed1994

Neuron-specific expression of the synapsin II gene is directed by a specific core promoter and upstream regulatory elements.

Synapsin II is an abundant peripheral membrane protein of synaptic vesicles that is expressed exclusively in neuronal cells. Here we report the isolation and characterization of the 5'-terminal region of the murine synapsin II gene. Primer extension and S1 nuclease protection analysis show that synapsin II gene transcription is initiated from a unique site. The synapsin II gene promoter contains no canonical TATA or CAAT boxes but has putative binding sites for the transcription factors Sp1, AP2, and NGFIA. This promoter is embedded in a large G+C-rich domain with characteristics of a CpG island. Transfection experiments using synapsin II-luciferase fusion genes demonstrate that the 5'-flanking sequence functions as a strong promoter in neuronal but not in nonneuronal cells. Deletion analysis reveals the presence of a neuron-specific core promoter (-79 to 153) and, upstream, two positive and one negative regulatory elements. The 5'-terminal region of the murine synapsin I gene was also cloned and sequenced. Although there is no extensive sequence homology between the 5'-flanking regions of the synapsin I and II genes, comparison analysis has identified two regions of homologous sequences, which may be involved in determining neuron specificity of the core promoters of these two genes.

Amino Acid Sequence↗
PubMed1994

A statistical analysis of factors related to symptomatic cerebral vasospasm.

A retrospective review of patients presenting to our institution with aneurysmal subarachnoid hemorrhage between 1980-1990 was accomplished. Eleven variables were examined as to their relationship to clinical vasospasm: age, sex, clinical grade, amount of subarachnoid blood on CT, aneurysm location, incidence of vasospasm, incidence of complications, use of calcium channel blockers, time to surgery, length of stay, and outcome. Data were analyzed with univariate and multivariate logistical regression methodology. By univariate analysis, age under 20, amount of subarachnoid hemorrhage, and clinical grade were associated with a higher risk of vasospasm. Using multivariate logistic regression, these factors, along with age under 35, were correlated as being predictive of clinical vasospasm. When all patients are grouped into either good or bad outcome, and a similar analysis is performed, only in the poor outcome group is the amount of subarachnoid hemorrhage and clinical grade correlated with vasospasm. This suggests that there is a group of patients with a predisposition to vasospasm that is independent of subarachnoid hemorrhage and clinical grade, and that these patients may have a more favorable outcome.

Adolescent↗
PubMed1994

The use of lobectomy in the management of severe closed-head trauma.

A retrospective review is presented of 20 patients with traumatic brain injury who were treated during the course of their illness by lobectomies either after a herniation or other significant deterioration or to reduce elevated intracranial pressure. All the patients suffered from blunt head trauma. Patient ages ranged from 19 to 59 years (average, 34 yr). The initial Glasgow Coma Scale score ranged from 3 to 15 (average, 8.2). There were 14 frontal lobectomies, 2 temporal, 3 frontal and temporal, and 1 occipital. Surgery was performed between 0 and 8 days after injury (average, 2.8). Outcome was favorable (good or moderately disabled) in 11 patients and unfavorable (severely disabled, persistently vegetative, or dead) in 9. No patients survived in a persistently vegetative state. A higher initial Glasgow Coma Scale score was positively correlated with a more favorable outcome (P < 0.03). Younger patients also showed a significant positive relationship to outcome (P < 0.0005). Better pupillary reactivity showed a significant trend toward a more favorable outcome (P < 0.04). The type of lesions identified on computed tomographic scans had no association with outcome. A lobectomy can be a useful adjuvant in the management of severe brain injury, especially in younger patients with relatively higher initial Glasgow Coma Scale scores who subsequently deteriorate or develop elevated intracranial pressure.

Adult↗
PubMed1994

Cytokine expression in radiation-induced delayed cerebral injury.

Radiation-induced delayed brain injury is a well-documented complication of both standard external beam radiation (teletherapy) and interstitial brachytherapy; however, the cause of this damage has not been determined. Cytokines and growth factors are important regulatory proteins controlling the growth and differentiation of normal and malignant glial cells, which have been implicated in the tissue response to radiation injury. Six snap-frozen brain biopsies showing radiation injury were obtained from four patients harboring malignant gliomas who underwent either postoperative external beam and/or stereotactic interstitial brachytherapy at standard dosages. The specimens showed variable amounts of gliosis, tissue necrosis, calcification, inflammation, and vascular proliferation and hyalinization. Frozen tissue sections were examined for the presence of infiltrating lymphocytes, macrophages, cytokines, and other immunoregulatory molecules by the use of a panel of specific monoclonal and polyclonal antibodies. All specimens showed diffuse T cell infiltration with both CD4+ and CD8+ cells. Infiltrating activated macrophages (CD11c+, HLA-DR+) were prominent in five of six cases. Tumor necrosis factor-alpha and interleukin-6 immunoreactivity was prominent in four of six cases and was predominately localized to macrophages. Transforming growth factor-beta astrocytic and macrophage immunoreactivity was present at moderate levels in all cases. This study suggests that in radiation necrosis, interleukin-1 alpha, tumor necrosis factor-alpha, and interleukin-6 are expressed, predominately by infiltrating macrophages.

Adult↗
PubMed1993

Beet western yellows virus-associated RNA: an independently replicating RNA that stimulates virus accumulation.

Infections of plants by subviral RNA agents, alone or in association with virus genomic RNA molecules, are well known. The ST9 strain of beet western yellows virus encapsidates not only the 5.6-kilobase genomic RNA that is typical of luteoviruses, but also a 2.8-kilobase-associated RNA that has a distinct nucleotide sequence. The ST9-associated RNA has been postulated to be a satellite RNA, which by definition would be capable of replicating only in coinfections with beet western yellows virus or closely related viruses. To characterize the associated RNA, we inoculated protoplasts and leaves with in vitro transcripts of the virus genomic RNA and the ST9-associated RNA separately and in combination. Surprisingly, the ST9-associated RNA alone replicated efficiently in both protoplasts and leaves, and it stimulated accumulation of the virus genomic RNA in protoplasts. Thus, the ST9-associated RNA is a newly discovered type of plant infectious agent, which depends on its associated virus, beet western yellows virus, for encapsidation but not for replication.

Base Sequence↗
PubMed1993

The beet western yellows virus ST9-associated RNA shares structural and nucleotide sequence homology with carmo-like viruses.

Complementary DNAs corresponding to the virion RNAs of the ST9 isolate of beet western yellows virus (ST9 BWYV) were cloned and the complete, 2843 nucleotide sequence of a unique RNA associated with ST9 BWYV, the ST9-associated RNA (ST9 aRNA), was determined. Three ORFs with deduced translation products of molecular weights 22,600, 12,500, and 35,900, respectively, and a small ORF, potentially encoding for a 3400 molecular weight protein, were identified in the ST9 aRNA sequence. Possible gene products of the ST9 aRNA were identified by in vitro translation analysis of the ST9 BWYV virion RNAs (the ST9 BWYV genomic RNA [ST9 BWYV gRNA] and the ST9 aRNA) and of transcripts representing the nearly full-length ST9 aRNA, individual ORFs, and specific ORF combinations. Proteins of 23,000 and 28,000 M(r) were derived from ORF 1 transcripts, while proteins of 25,000 and 35,000 M(r) were derived from ORF 3 transcripts. Larger proteins of 85,000 and 45,000 M(r) were also identified, and shown to possibly arise by continuous translation of ORFs 1, 2, and 3 (by possible readthrough and frameshift), or ORFs 2 and 3 (by possible frameshift), respectively. No products were detected from transcripts representing only ORF 2. Computer database searches and analyses indicated that the ST9 aRNA shares significant nucleotide sequence homology with carmo-like viruses, but not with its helper virus, BWYV. Amino acid sequence analyses also indicated that the ST9 aRNA ORF 2 and ORF 3 regions share extensive homology with putative RNA-dependent RNA polymerases of carmo-like viruses.

Amino Acid Sequence↗
PubMed1993

Hemangiopericytoma of the temporal bone presenting as a retroauricular mass.

An unusual case of a hemangiopericytoma arising from the temporal bone is presented. The patient was noted to have a postauricular mass and was neurologically asymptomatic. A preoperative magnetic resonance image and an angiogram revealed the tumor to be highly vascular. Preoperative embolization facilitated the surgical removal of the tumor by rendering it avascular. Current therapy consists of radical resection of the tumor with postoperative radiation therapy. Patients must be monitored carefully for local recurrence and systemic metastasis.

Adult↗
PubMed1992

Diffuse arteriovenous malformations: a clinical, radiological, and pathological description.

In a review of our series of patients with arteriovenous malformations (AVMs), a group with atypical angiographic and histopathological characteristics was discovered. Unlike the typical AVM, these lesions contained normal cerebral tissue between the abnormal vessels. We call these lesions diffuse AVMs, and think that this AVM represents one end of the AVM spectrum from a tight nidus to a diffuse lesion. The mean age of these patients was 18.1 years. Eight patients presented with an intracerebral hemorrhage, two with seizures, one with headache without hemorrhage, and one with ischemic symptoms compatible with vascular steal. Cerebral angiography revealed three AVMs to be 2 to 4 cm in diameter, four were 4 to 6 cm in diameter, and five were > 6 cm in diameter. Characteristic angiographic features included multiple small arterial feeders, small ectatic vessels in the malformation itself, multiple small draining veins, and a diffuse, puddling appearance of the contrast dye. Despite 16 operations in 11 patients, complete resection of the AVM was accomplished in only 8. The four patients with residual disease have received radiation therapy. Histopathology of the surgical specimens found AVM vessels interspersed among normal appearing neurons and white matter. Leptomeningeal angiodysplasia was noted when the cerebral cortex was involved. Gliosis was noted in some cases. Diffuse AVMs represent a difficult surgical challenge and recognition of the lesion aids in surgical planning.

Adolescent↗
PubMed1991

The standardized assessment of argyrophilic nucleolar organizer regions in meningeal tumors.

Tissue markers of cellular proliferation have been recently utilized as prognostic indicators in tumors of the central nervous system. Nucleolar organizer regions represent transcriptionally active sites of ribosomal deoxyribonucleic acid (DNA) and can be identified by a simple argyrophilic technique. The authors describe a standardized approach to the assessment of these argyrophilic nucleolar organizer regions in meningeal tumors. Twenty-five meningiomas were classified histologically into benign, atypical, or malignant groups. In addition, two hemangiopericytomas and one leptomeningeal melanoma were examined. Appropriate sections were silver stained and argyrophilic nucleolar organizer regions were counted in 200 nuclei. The mean argyrophilic nucleolar organizer region count was statistically different (p less than 0.001) between benign tumors (245 +/- 156, 1.23/cell), atypical tumors (497 +/- 135, 2.49/cell), and malignant tumors (921 +/- 59, 4.61/cell). The count for recurrent meningiomas (544 +/- 76) was also statistically different (p less than 0.02) from non-recurrent tumors (329 +/- 183). The standardized assessment of argyrophilic nucleolar organizer regions can be easily performed by any surgical pathology laboratory without specialized equipment and, in meningeal tumors, may be useful as an independent indicator of biological behavior.

Adult↗
PubMed1990

Legg-Calve-Perthes disease: clinical analysis of 57 cases.

The rarity of the Legg-Calve-Perthes disease (LCPD) in Chinese children in Hong Kong has been reported. However, this hip disorder is not uncommon among children in Taiwan between the ages of 3 and 9. Fifty-seven patients with LCPD were observed during a 4-year period. Of these, 47 hips in 43 patients were followed up through a significant course of the disease, with an average period of 38.8 months. The mean age at onset of symptoms was 6.6 years for boys and 7.1 years for girls. Over half of the patients (67%) were older than 6 years of age at onset of the disease. The male: female ratio was 5:1, and the incidence of bilateral involvement was 10%. The majority (85%) belonged to Catterall's group 3 or 4. The skeletal maturity of 17 (68%) these children was delayed an average of 31.8 months. Fifty-three percent of the patients were from families of low socioeconomic status. Delay in diagnosis and presentation with painless limp and stiffness were common. Orthotic management was employed in 15 hips. Surgical containment, either by varus-rotation femoral osteotomy or innominate osteotomy, was achieved in 16 hips. The remaining 16 hips received no treatment. The overall results showed an increase in improvement from 19% to 47% after active treatment of the disease. The chance of satisfactory treatment was reduced considerably when the disease started after the age of 6 years, this was especially obvious in untreated hips. No significant differenced in the healing time between the nonsurgical group and the surgical group was observed.

Age Factors↗
PubMed1987

Perioperative morbidity associated with operative resection of craniopharyngioma: a review of ten years experience.

A ten-year review of perioperative morbidity after operative resection of craniopharyngioma is presented. From 1974 to 1983, 23 patients underwent a total of 34 operations. Patients were subdivided into 95% or greater resection and partial resection groups. Features compared between the two groups included sodium, glucose, temperature, diabetes insipidus, major complications, neurological deficits and death. Patients undergoing 95% or greater resection had significant fluctuations in sodium, temperature and glucose (p less than .01). Diabetes insipidus and major postoperative complications were also significantly elevated in the 95% or greater resection group (p less than .05). Therefore, the extent of surgical resection correlated well with the degree of metabolic dysfunction and major postoperative complications. Careful assessment of surgical morbidity is warranted in the management of patients with craniopharyngioma.

Body Temperature Regulation↗
PubMed1987

Multiple thoracic disc herniations. Case report.

A patient with herniated thoracic discs in tandem is reported. The previous literature is reviewed. Difficulties with the preoperative diagnosis and the surgical approach to these lesions are discussed.

Adult↗
PubMed1979

Status epilepticus controlled by althesin infusion.

Althesin will control status epilepticus when other agents fail. Its major advantage over other agents is its lack of accumulation because it is readily metabolized. Three patients are reported and relevant literature is discussed.

Adolescent↗
PubMed1978

Prolonged curarisation in the presence of renal impairment.

Prolonged curarisation in the presence of renal failure occurred in six cases where pancuronium was used, and one case where alcuronium was used. The cases are presented with a brief review of the literature. Pancuronium must be used with great caution if postoperative reversal problems are to be avoided. Greater use of adjuvants will reduce requirements and may eliminate the problems encountered in renal failure.

Adult↗
PubMedDate not supplied

Sodium vanadate inhibits apoptosis in malignant glioma cells: a role for Akt/PKB.

The dual signal hypothesis of apoptosis holds that a common signal can activate both apoptotic and proliferative pathways. The fate of a cell is dependent on which of these two pathways predominates. In the MAPK family of kinases, ERK and JNK have been proposed to mediate apoptosis whereas the PI3K-stimulated kinase, Akt/PKB, has been shown to inhibit apoptosis. The object of this study was to determine the role of these kinases in a glioma model of apoptosis. We have previously shown that K252a induces apoptosis and inhibits kinase activity. In this study we confirm these results and show that the protein tyrosine phosphatase inhibitor sodium vanadate activates ERK, JNK and Akt/PKB, but does not stimulate proliferation. Vanadate did protect T98G cells from K252a-induced apoptosis, an effect that was abolished by addition of the PI3K inhibitor wortmannin. This suggests that PI3K and Akt/PKB may be responsible for mediating vanadate's protective effect on glioma cells. We conclude that the intracellular balance between protein phosphorylation pathways is a critical determinant of both cell proliferation and cell death.

Androstadienes↗
PubMedDate not supplied

Identification of okadaic-acid-induced genes by mRNA differential display in glioma cells.

To identify novel genes associated with apoptosis in glioma cells, we treated T98G glioma cells with okadaic acid (OA). Differential display using 15 random primers was performed on RNA extracted from these cells. Upregulated bands were excised from polyacrylamide gels and cloned. Northern blots were used to confirm RNA expression in T98G cells. 18 RNA fragments corresponding to the untranslated region of genes were identified and sequenced. Three unknown gene fragments were used to screen a fetal brain cDNA library resulting in three complete cDNA sequences. The three sequences corresponded to a human gene homologous to the yeast translation initiation factor Sui-1, a cAMP-regulated phosphoprotein, ARPP-16/19, and a novel gene designated O48. Transcription of Sui-1 increased in response to all stress factors tested, whereas ARPP only responded to OA. 2-kb and 4-kb O48 RNA species were identified. OA and stress factors increased 2-kb expression while K252a (protein kinase inhibitor) increased 4-kb expression. Differential display is effective for identifying genes associated with apoptosis. Novel genes may be identified by further analysis of the gene fragments identified in this study. The function of O48 is unknown.

Amino Acid Sequence↗