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Y S Ho

Publications and source records attributed to Y S Ho.

At least 145 records · Page 8Linked to original sources
PubMed1993

Cerebral sparganosis diagnosed and treated with stereotactic techniques. Report of two cases.

Infestation of the central nervous system with sparganum, the larva of Spirometra mansoni, is rare. Only 27 cases have been reported in the literature; however, the true incidence might be underestimated. Two cases are reported that were definitively diagnosed by stereotactic biopsy techniques. Without a positive histological diagnosis, the first case would have been diagnosed as having a metastatic brain tumor and a course of radiotherapy would probably have been initiated. Differentiation between granuloma of cerebral sparganosis and brain tumors such as meningiomas, gliomas, and metastatic tumors is often difficult before operation. Detailed magnetic resonance imaging might offer some help in such cases. Emphasis is placed on the increasing importance of stereotactic surgery in the diagnosis and treatment of an intracerebral mass lesion, including cerebral sparganosis.

Agricultural Workers' Diseases↗
PubMed1993

Eosinophilic granuloma of the skull--report of four cases.

Eosinophilic granuloma is a benign form of the three clinical variants of histiocytosis-X. It is an uncommon, localized granulomatous process, forming solitary or multiple lytic skeletal lesions, and primarily involving male children and young adults. We studied 4 cases, three boys and one girl, aged 4, 8, 27 and 12 years, in Chang Gung Memorial Hospital from 1981 to 1990. Their common presentation was the rapidly growing, painful, and protruding scalp masses without neurological deficits. En bloc excisions of these lesions were performed. Then radiotherapy was given postoperatively in two cases, chemotherapy in one, and no adjuvant treatment in one. During their follow-up period of 2 to 10 years, all 4 patients were well, without evidence of recurrence.

Adult↗
PubMed1993

Lupus nephritis, emphasizing tubulointerstitial lesions: a clinico-pathological analysis.

Tubulointerstitial lesions (TIL) such as interstitial inflammation, fibrosis and tubular atrophy are frequently found in classes of lupus nephritis. A retrospective study evaluate lupus nephritis, the relationship between TIL and glomerular lesions, and the significance of TIL in assessing the severity and prognosis for cases of lupus nephritis. Between June 1983 and Jan 1990, 492 renal biopsies were performed. Lupus nephritis was diagnosed in 37 patients who fulfilled the American Rheumatology Association (ARA) criteria for Systemic lupus erythematosus (SLE). The results showed a significant correlation between degree of TIL and impairment of renal function. Degree of TIL and severity of glomerular lesions must be considered simultaneously to predict renal function of patients with lupus nephritis.

Adolescent↗
PubMed1992

Extracellular superoxide dismutase, nitric oxide, and central nervous system O2 toxicity.

Although reactive O2 species appear to participate in central nervous system (CNS) O2 toxicity, the exact roles of different reactive O2 species are undetermined. To study the contribution of extracellular superoxide anion (O2-) to CNS O2 toxicity we constructed transgenic mice overexpressing human extracellular superoxide dismutase (ECSOD; superoxide:superoxide oxidoreductase, EC 1.15.1.1) in the brain. Remarkably, when exposed to 6 atm (1 atm = 101.3 kPA) of hyperbaric oxygen for 25 min, transgenic mice demonstrated higher mortality (83%) than nontransgenic litter-mates (33%; P < 0.017). Pretreatment with diethyldithiocarbamate, which inhibits both ECSOD and Cu/Zn superoxide dismutase (Cu/Zn SOD) activity, increased resistance to CNS O2 toxicity, in terms of both survival (100% in transgenics and 93% in nontransgenics) and resistance to seizures (4-fold increase in seizure latency in both transgenic and nontransgenic mice; P < 0.05). Thus, O2- apparently protects against CNS O2 toxicity. We hypothesized that O2- decreased toxicity by inactivating nitric oxide (NO.). To test this, we inhibited NO. synthase (EC 1.14.23) with N omega-nitro-L-arginine to determine whether NO. contributes to enhanced CNS O2 toxicity in transgenic mice. N omega-nitro-L-arginine protected both transgenic and nontransgenic mice against CNS O2 toxicity (100% survival and a 4-fold delay in time to first seizure; P < 0.05), as well as abolishing the difference in sensitivity to CNS O2 toxicity between transgenic and nontransgenic mice. These results implicate NO. as an important mediator in CNS O2 toxicity and suggest that ECSOD increases CNS O2 toxicity by inhibiting O2(-)-mediated inactivation of NO.

Animals↗
PubMed1992

Characterization of the transcription activator protein C1 of bacteriophage P22.

We cloned, expressed, and purified the positive regulatory protein C1 of the temperate phage P22 of Salmonella typhimurium. The purified protein was characterized as to its amino acid composition, protein sequence, molecular weight, and antigenicity. P22 C1 was shown to be a tetrameric protein composed of four identical subunits with M(r) = 10,000. Moreover, we identified and characterized two P22 C1-dependent phage promoters, P(RE) and Pa23, whose function was completely dependent on C1 both in vitro and in vivo. These two promoters share a common TTGCN6TTGC/T motif in their -35 regions, the same motif recognized by the analogous phage lambda transcription activator protein cII. P22 C1 protein bound selectively to this region and centered on the TTGC repeat motif. Binding and transcription experiments demonstrated that the two promoters respond coordinately to C1 activation. Last, in contrast to lambda cII, the C1 protein exhibited little cooperativity with Escherichia coli RNA polymerase for DNA binding, but because of its stronger inherent binding ability, achieved an overall promoter affinity similar to that observed for cII at its cognate promoter signals.

Amino Acid Sequence↗
PubMed1992

Cloning and characterization of the rat glutathione peroxidase gene.

The increased activity of glutathione peroxidase (GSHPx) in rat lungs is associated with the development of tolerance of the animals to hyperoxia. To understand further the regulation of expression of this enzyme, the molecular structure of the corresponding rat gene was characterized. The rat GSHPx gene consists of two exons interrupted by a single intron of 217 base pairs. The same initiation sites for transcription were found to be utilized in both lung and liver. The promoter of the GSHPx gene contains neither a 'TATA' box nor a 'CAAT' box. Instead, it comprises two copies of Sp1 binding motif and one copy of AP-2 binding motif. These features of the promoter may offer a clue to the mechanisms by which the expression of this gene is controlled.

Amino Acid Sequence↗
PubMed1992

Intraventricular neurocytoma: four cases report.

Intraventricular neurocytoma, a newly identified disease entity with probably not so rare incidence, has several distinctive clinico-pathological characteristics. Four cases are presented. As in the other cases reported in the literature [1-7], the characteristic features are young age, location close to the junction of the septum pellucidum and foramen of Monro, and well-differentiated neuronal origin pathologically.

Adult↗
PubMed1992

Clinicopathological evaluation of 78 astrocytomas in Taiwan with emphasis on a simple grading system.

The grading systems of astrocytic tumors have long been the subject of controversy. A simple, objective and effective grading method is urgently needed for the evaluation of prognosis and the planning of treatment. This study investigated the relationship of clinical prognostic factors to the grading method of Daumas-Duport. This method determines the grade of tumor based on the presence or absence of four morphological criteria: nuclear atypia, mitosis, endothelial proliferation, and necrosis. A total of 143 astrocytic tumors were reviewed and screened, of which 65 ordinary and 13 pilocytic astrocytomas were selected for grading and comparison. Among ordinary astrocytomas, the grading method distinguished 9.2% grade 1, 26.2% grade 2, 36.9% grade 3, and 27.6% grade 4. At least 2-year follow-up was available on all surviving patients. Median survival was 57, 32, 12.5, and 8 months in grades 1, 2, 3, and 4 tumors, respectively. By a multiple regression model and analysis of variance, grade is significantly associated with survival (total regression coefficient r = 0.711). Age lost its significance on survival after multiple regression analysis. Sex, location, and surgical procedure were all unrelated to survival after regression. The age distribution and survival of patients with pilocytic astrocytomas revealed that this is a distinct disease entity and should not be admixed with ordinary astrocytomas in a grading scheme.

Adolescent↗
PubMed1992

Neoadjuvant chemotherapy with cisplatin, vincristine, and bleomycin and radical surgery in early-stage bulky cervical carcinoma.

Neoadjuvant chemotherapy consisting of 2-3 courses of cisplatin, vincristine, and bleomycin was used in the primary treatment of 36 consecutive patients with locally advanced early-stage cervical carcinoma [International Federation of Gynecology and Obstetrics (FIGO) stages Ib or IIa; tumor size, greater than or equal to 4 cm]. The effectiveness of the preoperative chemotherapy was evaluated in the surgical specimens. Among the 33 evaluable patients, the overall clinical response rate was 84.8%, which included a complete response in 8 patients (24.2%) and a partial response in 20 subjects (60.6%). No residual tumor was found in the surgical specimens obtained from 2 complete responders. This therapy induced varying degrees of tumor shrinkage and rendered radical surgery feasible in all evaluable cases despite the initial bulky size of the lesions. No significant difference was observed in the response rate according to age and disease stage. Lymph-node metastases were found after chemotherapy in 18.2% (6/33) of the patients. Grade II and III hematological toxicities occurred in 23.3% of the 90 chemotherapy cycles completed. Nausea and vomiting occurred to a mild to moderate degree in 75 (83.3%) cycles. These preliminary results suggest that the administration of induction chemotherapy involving two to three courses of cisplatin, vincristine, and bleomycin prior to surgery is effective in reducing the tumor volume and in providing better circumstances for surgical removal of the early yet bulky cervical tumors and results in tolerable toxicity. This protocol is now undergoing prospective randomized trials to test its impact on long-term survival.

Adult↗
PubMed1992

Hepatotoxicity and hepatocarcinogenicity in rats fed squid with or without exogenous nitrite.

The popular seafood squid contains high levels of naturally occurring amines such as dimethylamine (DMA) trimethylamine and trimethylamine-N-oxide (TMAO). The hepatotoxicity and hepatocarcinogenicity of squid with or without exogenous nitrite were investigated in rats. Acute necrosis including polymorphogenic neutrophil infiltration, haemorrhage and cholangiofibrosis were observed in the livers of most rats fed squid. Hepatocellular carcinoma (HCC) was induced in two out of 12 rats (16%) by feeding 10% squid in Purina rat chow for 10 months. The incidence of HCC was increased to four out of 10 rats (33%) when 0.3% NaNO2 was added to the above diet. At the end of the experiment a marked elevation of serum gamma-glutamate transferase was observed in treated groups, but no significant changes in the activities of serum glutamic-oxaloacetic transaminase and glutamic-pyruvic transaminase were detected. Vitamin C (0.3%) gave partial protection against hepatic damage. The concentration of DMA in squid is estimated to be 0.19%; this concentration did not induce HCC under the experimental conditions used. Therefore it is suggested that another major naturally occurring amine in squid, TMAO, could be one of the important factors involved in the induction of hepatotoxicity and hepatocarcinogenicity in rats.

Animals↗
PubMed1992

Intracerebral malignant fibrous histiocytoma: case report and review of the literature.

A 50-year-old woman developed an intracerebral malignant fibrous histiocytoma at the site of a previously clipped aneurysm in the right temporal lobe. This tumor rarely originates within the brain. Review of the literature suggests that postoperative and/or postirradiation effects may contribute to the growth of this particular tumor.

Brain Neoplasms↗
PubMed1991

Overproduction of human Mn-superoxide dismutase modulates paraquat-mediated toxicity in mammalian cells.

Manganese superoxide dismutase (MnSOD) is a nuclear encoded mitochondrial matrix enzyme that functions to scavenge superoxide radicals. The human MnSOD cDNA under the transcriptional control of a human beta-actin promoter was introduced into mouse C3H10T1/2 cells by cotransfection with a recombinant plasmid containing the NeoR selectable marker. C3H10T1/2 transformants (C3H-SOD) were obtained that expressed high levels of authentic enzymatically active human MnSOD. Overexpression of the MnSOD gene did not affect the protein levels of CuZnSOD, catalase (CAT), or glutathione peroxidase (GPX) in the transformants. Treatment of cells with paraquat was less toxic to the C3H-SOD cells than to the control cells. These results are consistent with the possibility that superoxide radicals are mediators of paraquat cytotoxicity.

Animals↗
PubMed1991

Surfactant apoprotein in adult rat lung compartments is increased by dexamethasone.

The distribution of the major surfactant apoprotein (SP-A) in adult rat lung was determined in order to gain insight into its metabolism, including packaging of SP-A into lamellar bodies. The effect of glucocorticoid treatment on surfactant apoprotein was studied to test whether regulation of surfactant apoprotein genes, which has been described for the fetal lung, can be demonstrated in the adult animal. We measured the amounts of immunoreactive SP-A in several lung tissue compartments and lavage fractions from control animals and from the lungs of rats given dexamethasone for 1 wk. Protein and phospholipids were measured, SP-A was quantitated with a noncompetitive enzyme-linked immunoabsorbent assay (ELISA) and SP-A, SP-B, and SP-C mRNAs were estimated by Northern blotting. We found an 85-fold concentration of SP-A in a lamellar body-rich fraction compared with lung tissue homogenate and we calculated that as much as one-half of all the tissue SP-A might be accounted for by a lamellar body pool. After 1 wk of dexamethasone treatment, there was an increase in adult rat lung SP-A, SP-B, and SP-C mRNA and a substantial increase in tissue and lavage fluid immunoreactive SP-A pools. Lamellar body fraction SP-A content per lung was 1.4-fold higher after dexamethasone, and there was a fivefold increase in the lavage SP-A pool, much of which was inseparable from the alveolar macrophages. We conclude that SP-A is concentrated in the lamellar bodies of type II cells, that dexamethasone treatment increased all surfactant mRNAs, and that it increased SP-A content in adult rat lung.

Animals↗
PubMed1991

Molecular structure of a functional rat gene for manganese-containing superoxide dismutase.

The manganese-containing superoxide dismutase (MnSOD) constitutes one of the major cellular defense mechanisms against the toxic effects of superoxide radical. The development of tolerance in adult rats to lethal exposure of O2 (100%) after pre-exposing them to a sublethal concentration of O2 (85%) was found to be closely associated with the increased activity of this enzyme in the lungs. Further experiments have shown that the transcriptional rate of the gene coding for MnSOD in rat lungs is increased at day 3 of 85% O2 exposure. To elucidate the nature of this transcriptional activation during hyperoxic insults, we chose to first understand the structure of the rat MnSOD gene. Three overlapping rat genomic fragments were isolated, and the DNA sequence containing the whole MnSOD gene was completely determined. The rat MnSOD gene contains at least five exons and is located in one piece of 16.4-kb EcoRI genomic DNA fragment. However, Southern blot analysis of total rat genomic DNA probed with MnSOD cDNA revealed an additional hybridizing 8.6-kb EcoRI genomic fragment besides the 16.4-kb one. To clarify the origin of this unexpected hybridizing genomic fragment, three unique genomic sequences derived from the promoter, intron 2, and the 3' untranslated region of the genomic clones were used to rehybridize the same Southern blot filter and were found to only hybridize to the 16.4-kb but not 8.5-kb EcoRI genomic fragment. These data suggest: (1) two MnSOD genes are present per haploid rat genome, and (2) all three cloned genomic fragments are derived from the MnSOD gene, which is located in the 16.4-kb EcoRI genomic fragment.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1991

Lymphomas of true histiocytic origin. Expression of different phenotypes in so-called true histiocytic lymphoma and malignant histiocytosis.

The authors determined the phenotypes of neoplastic cells in true histiocytic lymphoma and malignant histiocytosis by using a large panel of monoclonal antibodies and enzyme histochemistry procedures. Although the phenotypes overlapped slightly, the authors noted a distinct pattern in these tumors. The tumor cells of malignant histiocytosis generally expressed the monocyte markers CD11b, CD11c, CD14, and CD45, especially after induction with phorbol ester. In contrast, the tumor cells of true histiocytic lymphoma exhibited a marker expression very similar to that of Reed-Sternberg cells in Hodgkin's disease. These cells expressed markers CD30, 2H9, and 1A2, but rarely expressed CD11b, CD11c, CD14, or CD45. Regardless of their cytologic features, the tumor cells from both types of histiocytic lymphoma exhibited diffuse nonspecific esterase and acid phosphatase activities, and they expressed histiocyte markers CD15, CD68, LN5, 1E9, and M387 to varying degrees. The tumor cells from both lymphomas did not exhibit T- or B-cell markers, T-cell receptor or immunoglobulin gene rearrangements, or gene translation products, even when they were induced with phorbol ester. The phenotypic expression in these two histiocytic malignancies suggests that they are derived from different types of histiocytes, or from histiocytes in different stages of maturation or differentiation, or from histiocytes that have distinct mechanisms of tumorigenic transformation. The expression of circulating monocyte markers in malignant histiocytosis suggests that this tumor originates in monocytes or free histiocytes, whereas the phenotype of true histiocytic lymphoma is compatible with an origin in fixed histiocytes, which generally are devoid of the monocyte markers CD11b and CD14.

Adolescent↗
PubMed1990

Effect of germanium on 1,2-dimethylhydrazine-induced intestinal cancer in rats.

Through recent research, the trace element, germanium, was found to have an anticancer effect. The purpose of this research was to determine the effect of germanium on 1,2-dimethylhydrazine-induced intestinal cancer in rats. Ninety-six 8-week-old Sprague-Dawley male rats were divided into 4 groups, with 24 rats in each group. All received dimethylhydrazine, 20 mg/kg body weight, subcutaneously, once a week for 20 weeks. Except for one control group, the other three groups were subdivided into six groups and administered three different kinds of germanium (inorganic germanium, organic germanium, and natural organic germanium) one month before and during dimethylhydrazine treatment, and during dimethylhydrazine treatment, respectively. Twenty-four weeks after carcinogen exposure, all surviving animals were sacrificed and examined for intestinal tumors. The number and location of the tumors were recorded and the pathology examined. The incidence of intestinal cancer in the control group (dimethylhydrazine only) was 91 percent; in groups provided with inorganic germanium one month before and during dimethylhydrazine treatment, and during dimethylhydrazine treatment only, it was 91 and 78 percent; in groups provided with organic germanium one month before and during dimethylhydrazine treatment, and during dimethylhydrazine treatment only, it was 64 and 64 percent; in groups provided with natural organic germanium one month before and during dimethylhydrazine treatment and during dimethylhydrazine treatment only, it was 50 and 45 percent. From these results, the authors conclude that natural organic germanium has the best prevention effect for intestinal cancer in this animal model (P less than 0.01), followed by organic germanium (P less than 0.05). Inorganic germanium has no effect. However, there is no difference in the cancer prevention effect of germanium provided one month before and during dimethylhydrazine treatment, and during dimethylhydrazine treatment only.

1,2-Dimethylhydrazine↗
PubMed1990

Spinal extradural cavernous hemangioma.

Three cases of isolated spinal extradural cavernous hemangiomas are reported, two in the thoracic and one in the lumbar region. One of them manifested as acute cord compression, the other two as chronic progressive myelopathy or radiculopathy. A total excision or subtotal excision with irradiation was performed. All of them had good functional recovery. The clinical picture, radiological diagnosis, and optimal method of treatment are discussed. The relevant literature is reviewed.

Adult↗