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Biomedical subjects

T Y Shih

Publications and source records attributed to T Y Shih.

At least 19 recordsLinked to original sources

Atlantal stenosis: a rare cause of quadriparesis in a child. Case report.

The authors report the case of a 3-year-old boy who suffered from quadriparesis and respiratory distress after failing to execute a somersault properly. Neuroimaging revealed spinal cord contusion with marked spinal canal stenosis at the level of the atlas. No subtle instability, occult fracture, or other congenital abnormalities were confirmed. Spinal cord contusion with marked canal stenosis is rare, and only several adult cases have been reported. Severe stenosis at the level of the atlas may predispose individuals to severe spinal cord contusion, as occurred in our patient after sustaining trivial trauma.

Adult↗

Fibrosis of the omohyoid muscle--an unusual cause of torticollis.

An 11-year-old boy had a left neck mass with torticollis. On exploration, a fibrotic mass in the superior belly of the left omohyoid muscle was found, which shortened the muscle and pulled the hyoid bone downward. Resection of the fibrotic muscle was performed. The patient recovered well after the operation with resolution of his torticollis.

Child↗

Mediastinal lipoblastoma with intraspinal extension: MRI demonstration.

Lipoblastomatous lesions are mesenchymal tumors of embryonal white fat and are classified into two forms: a superficial, well-defined mass (lipoblastoma) or a deep, infiltrative lesion (lipoblastomatosis). We report an unique case of mediastinal lipoblastoma in a 17-month-old boy which harbored a dual nature and exhibited the characteristics of both forms, a large well-encapsulated intrathoracic main tumor with focal infiltrative features at the thoracic inlet and transforaminal intraspinal extension forming a long-segment extradural mass. In addition to specific signal characterization of a fatty mediastinal mass with intratumoral streaks and whorls corresponding to the fibrovascular network, magnetic resonance (MR) imaging offered clear demonstration of the chest wall, lower neck and intraspinal extension, which was important for preoperative planning.

Adipose Tissue↗

Juvenile fibromatosis of the posterior mediastinum with intraspinal extension.

Chest radiography, CT, and MR imaging were performed in a 3-year-old girl who had posterior mediastinal fibromatosis with transforaminal intraspinal and chest wall extension. Chest radiographs and CT scans showed a slow-growing, noncalcified but locally aggressive left paravertebral mass. The mass was slightly hyperintense relative to muscle on both T1-weighted and fast spin-echo T2-weighted MR images.

Child, Preschool↗

Posterior cerebral artery aneurysm in a two-year-old girl.

Intracranial aneurysms are seldom encountered in the pediatric age group, and those within the posterior circulation are even more rare. Intracranial aneurysms in children differ from adult aneurysms in size, distribution, histology and incidence of symptoms. The authors report a 2-year-old female patient with a posterior cerebral artery aneurysm presenting with seizures, right third nerve palsy and right hemiparesis caused by compression of the contralateral cerebral peduncle. The patient underwent a pterional craniotomy and clipping of the aneurysm. Right oculomotor nerve palsy remained postoperatively. We review the literature and discuss the characteristics of aneurysms of the posterior cerebral artery and those in early childhood.

Cerebral Angiography↗

Acquired immunodeficiency syndrome with CNS toxoplasmosis: a case report.

Central nervous system (CNS) toxoplasmosis is an important infectious complication of acquired immunodeficiency syndrome (AIDS) which appears to result from reactivation of a previously acquired infection and requires prolonged treatment. A 31-year-old male presented in a drowsy mental state and with an unstable gait. Computerized tomographic (CT) scan and magnetic resonance imaging (MRI) showed multiple nodular lesions in the cerebrum and cerebellum; the seropositivity for the human immunodeficiency virus (HIV-1) and high serum IgG toxoplasma titers were also demonstrated. A presumptive diagnosis of CNS toxoplasmosis was based on neurological signs and neuroradiological findings. This was confirmed by improvement in both clinical and neuroradiological pictures during treatment with pyrimethamine and clindamycin. Four months later, however the patient died of intracranial hemorrhage and massive upper GI bleeding.

Acquired Immunodeficiency Syndrome↗

Coexisting IgA nephropathy and leukocytoclastic cutaneous vasculitis associated with ankylosing spondylitis: a case report.

A patient with ankylosing spondylitis and coexisting IgA nephropathy and leukocytoclastic cutaneous vasculitis is described. Renal biopsy demonstrated mesangial proliferative glomerulonephritis with prominent IgA, C3 and fibrin deposition in the glomeruli. Simultaneously, leukocytoclastic cutaneous vasculitis with prominent IgG, IgA and C3 deposition of dermal vessel wall was also observed in the skin biopsy specimen. Such associations have been previously reported in only four cases. This report once again indicates that antigenic mucosal stimulation may play an important role in the pathogenesis of ankylosing spondylitis.

Adult↗

Lupus in Chinese male: a retrospective study of 61 patients.

BACKGROUND: Systemic lupus erythematosus (SLE) has traditionally been considered a disease of women, and is uncommon in men. In recent years, several large clinical series of male lupus patients have been reported. As no known data are available for lupus in males from Taiwan, a retrospective analysis of data from male lupus patients was done to determine whether these patients differed from other series of male or female SLE patients in the literature. METHODS: Sixty-one male lupus patients, diagnosed and followed in Tri-Service General Hospital, between 1983 and 1993, were studied and their data analyzed, retrospectively. RESULTS: The mean age of diagnosis was 30 +/- 17 (mean +/- SD, range: 13-81) years. The peak age of diagnosis was between 13 and 40 years. The mean duration of follow-up was 36 +/- 36 (range: 2-256) months. The 1-, 5- and 10-year survival rates were 84%, 76% and 75%, respectively. The frequency of clinical manifestations were renal disease, 75%; malar rash, 70%; arthritis, 60%; fever, 56%; photosensitivity, 48%; pleuritis, 39%; pericarditis, 31%; alopecia, 31%; mucosal ulcers, 29%; neuropsychiatric disease, 26%; discoid lupus, 21%; vasculitis, 15%; Raynaud's phenomenon, 10%; and lymphadenopathy, 2%. The frequency of abnormal laboratory findings were antinuclear antibodies (ANA), 95%; hypocomplementemia, 77%; antibodies to double-stranded DNA (anti-dsDNA), 57%; leukopenia, 44%; lupus erythematosus (LE) cells, 39%; anti-Ro, 39%; anti-Smith antibodies (anti-Sm), 19%; thrombocytopenia, 18%; rheumatoid factor, 17%; anti-ribonucleoprotein antibody (anti-RNP), 14%; autoimmune hemolytic anemia, 8%; false-positive venereal disease research laboratory test (VDRL), 6% and anti-La, 4%. CONCLUSIONS: In a review of the 61 ethnic Chinese male lupus patients, a higher frequency of renal disease, malar rash and photosensitivity, but a lower frequency of arthritis and lymphadenopathy, compared to previous reports of Caucasians. There were no significant immunological differences from other series of male lupus, except a lower frequency of anti-dsDNA. In general, poor prognosis was noted for male lupus patients here.

Adolescent↗

A case of demyelinating disease with clinical and radiological features mimicking cerebral tumor.

Demyelinating disease may present with clinical and radiological features mimicking brain tumor. A 43-year-old man was admitted because of progressive right hemiparesis, facial weakness and dysarthria. Computed tomographic scans revealed two expansive lesions in the left frontal lobe and midbrain, respectively. A brain tumor or metastatic lesion was suspected. The patient underwent left frontal craniotomy and the surgical biopsy revealed a demyelinating process. The patient, however, had a poor response to steroid treatment and died two months later. The possible nature of demyelinating disease in this case is discussed.

Adult↗

Magnetic resonance imaging of radiation necrosis after radiotherapy for acromegaly: report of a case.

A total 5,600 cGy in 28 fractions in 44 days was delivered to a 53-year-old woman with acromegaly after transsphenoid removal of a pituitary adenoma. Sixteen months later, she suffered a progressive loss of vision. Radiation optic neuropathy was diagnosed. A T1-weighted imaging showed gadolinium-enhanced lesions in the optic chiasm, pituitary stalk and hypothalamus. Magnetic resonance imaging is uniquely suited to detect radiation injury to the sellar region. The complications of radiation therapy for benign tumor can be severe even by current standard procedures.

Acromegaly↗

Biological activity of a K-ras mutant that contains the 12R/59T/116Y mutations.

The 12R/59T/116Y mutations have been shown to confer a dominant negative activity on H-ras oncogene (H-ras 116Y). To determine whether this event is unique for H-ras, we introduced the same mutations into K-ras oncogene. This mutant, K-ras 116Y, suppressed transformed phenotypes induced by overexpression of H-ras proto-oncogene. NIH3T3 cells expressing K-ras 116Y were resistant to transformation by v-fes oncogene. Analysis of chimaeras between H- and K-ras 116Y showed that the C-terminal variable region determines the level of suppressor activity. These results suggest that these mutations are applicable to other GDP/GTP binding proteins.

3T3 Cells↗

Resistance of NIH3T3 cells to v-fes transformation induced by a dominant negative H-ras mutant.

NIH3T3 cells carrying a dominant negative H-ras mutant 116Y acquired resistance to transformation by some PTK oncogenes, i.e., v-fes, v-abl, and v-fms, but were sensitive to viral ras and serine threonine kinase oncogenes, v-raf and v-mos. One clone, designated 1-20, infected with v-fes (1-20 fes) exhibited flat morphology and anchorage-dependent cell growth, as did noninfected 1-20 cells. The 1-20 fes cells expressed v-fes oncogene and produced transforming viruses, although these levels were much lower than those in NIH3T3 cells infected with v-fes (NIH3T3 fes). v-fes mRNAs in NIH3T3 fes cells rapidly increased after infection, while accumulation of the v-fes transcripts in 1-20 fes cells was significantly prolonged. Total tyrosine phosphorylation in both NIH3T3 fes and 1-20 fes cells was correlated with the amounts of pp110v-fes. A few proteins were phosphorylated only in NIH3T3 fes but not in 1-20 fes cells. These results suggest that the cellular ras is involved in a signaling pathway from pp110v-fes and this signal stimulates v-fes expression. Inhibition of the ras function may down-regulate this pathway and result in resistance to transformation by v-fes.

3T3 Cells↗

Induction and progression of the transformed phenotype in cloned rat embryo fibroblast cells: studies employing type 5 adenovirus and wild-type and mutant Ha-ras oncogenes.

Transformation of cloned rat embryo fibroblast (CREF) cells with the wild-type 5 adenovirus (wtAd5) transforming genes E1A and E1B (which extend from 0 to 11.2 map units) results in morphologically transformed cells that exhibit an increased saturation density in monolayer culture and display an anchorage-independent phenotype. WtAd5-transformed CREF (wtAd5 CREF) cells do not, however, induce tumors when injected subcutaneously into athymic nude mice or syngeneic Fischer rats. We have analyzed the effect of the ras oncogene and site-specific mutants in the ras oncogene that result in p21 proteins with altered biochemical properties on the oncogenic and metastatic properties of singly (ras) and doubly (ras + wtAd5) transformed CREF cells. Transformants expressing the wild-type ras p21 protein and ras mutants producing p21 proteins that retained GTP-binding properties grew in agar, induced tumors in nude mice and syngeneic rats, and metastasized to the lungs of rats when injected into their tail veins. In contrast, cells transformed with the ras mutant 116K (which contains a mutation at residue 116 that produces a Lys instead of an Asn and does not bind GTP or induce CREF cells to grow in agar) did not become morphologically transformed and were not oncogenic when injected subcutaneously into either nude mice or Fischer rats; further, such cells were not metastatic when injected into the tail veins of Fischer rats. When the wild-type ras or the ras mutants, including 116K, were expressed in nontumorigenic E1A-plus-E1B-expressing wtAd5 CREF cells, transformed cells induced tumors in both types of animals. The CREF cells doubly transformed with 116K + wtAd5, unlike transformants containing the wild-type ras and the other ras mutants that still retained GTP binding, were still unable to induce lung metastases. In addition, 116K + wtAd5-transformed CREF cells also did not display any alterations in morphology distinguishable from wtAd5 CREF cells and were not able to grow in agar with increased efficiency. These results indicate that the loss of GTP-binding ability by this mutant p21 ras protein eliminated the ability of these proteins to induce an oncogenic phenotype in an immortal but normal CREF cell line. However, the mutant ras could cooperate with wtAd5 transforming genes in transformed CREF cells to make these cells progress to an oncogenic (but not metastatic) phenotype.

Adenoviridae↗

Tumorigenicity, metastasis and suppression of MHC class-I expression in murine fibroblasts transformed by mutant v-ras deficient in GTP binding.

We have introduced point mutations in v-rasH to study their effects on biochemical and biological properties of the ras-encoded protein p21. Several of these mutant proteins do not bind GTP and thus lack GTPase activity, while others were shown to have their GTP binding reduced. We have introduced these ras mutants into NIH 3T3 fibroblastoid cells to study major parameters of clinical importance which are associated with neoplastic transformation, particularly MHC expression in cells, metastasis and tumorigenesis in both nude mice and immune competent mice. Our data show that certain mutations in v-ras differentially affect the expression of the transformed phenotype. Mutant ras molecules deficient in GTP binding fail to generate rapidly progressing tumors in immune competent mice, and not all morphologically transformed cells were capable of experimental metastasis. Cells transformed by certain v-ras mutants form tumors in immunocompetent mice and show reduced expression of MHC class-I antigens. Other cells are morphologically transformed and tumorigenic in athymic nude mice, but fail to form tumors in normal mice and show levels of MHC class-I antigen expression similar to non-transformed 3T3 cells. The inverse relationship between MHC class-I-antigen expression and the degree of transformation in fibroblastoid cells suggests that the ras gene product could be involved in regulating MHC expression.

Animals↗