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S M Liu

Publications and source records attributed to S M Liu.

At least 55 records · Page 3Linked to original sources
PubMed1998

Interdigitating reticulum cell tumor of lymph node: a case report and literature review.

Interdigitating reticulum cell (IRC) tumor is a rare tumor arising from the antigen-presenting cell - interdigitating reticulum cell. A 41-year-old male presented with lumps in the left neck and bone pain. Further investigations revealed multiple left neck and para-aortic lymphadenopathy, and multiple bony lesions. Histological examination of the lymph node showed proliferation of unusual, large, round neoplastic cells mimicking large cell lymphoma. Immunophenotypic and ultrastructural studies confirmed this tumor to be arising from an interdigitating reticulum cell. A review of reported IRC tumors illustrates the variability of this tumor in clinical and pathological features, which differ from other dendritic reticulum cell tumors.

Adult↗
PubMed1998

Colicinogeny among Escherichia coli serotypes, including O157:H7, representing four closely related diarrheagenic clones.

Twenty-seven diarrheagenic Escherichia coli (DEC) strains from five closely related, genetically distinct clones (DEC 3, 4, 8, 9, and 10), representing serotypes commonly associated with Shiga-like toxin production, i.e., O15:H-, O26:(H11, H-), O111:(H8, H11, H-), and O157:H7, were evaluated for colicinogeny on Luria agar or Luria agar containing 0.25 microgram/ml mitomycin C to induce colicin production. Ten (37%) of the DEC strains tested were colicinogenic. One of 11 serotype O157:H7 strains, DEC strain 4E, produced a colicin identified as Col D. DEC strains 8B, 9D, and 10B produced Col E1, whereas DEC strain 10A produced Col E2. DEC strains 8A, 8E, 10C, 10E, and 10F produced "untypable" colicins that killed almost all Pugsley Colicin Reference Set strains and the other DEC strains tested. To aid with further characterization of the colicins, plasmids extracted from each colicin-producing (Col+) DEC strain were used to transform E. coli strain DH5 alpha. All Col+ DH5 alpha transformants contained one plasmid ranging in size from 1.3 to 10 kb. Some transformants were stable colicin producers whereas others were unstable. The inhibitory activity and colicin sensitivity and insensitivity profiles of the Col+ transformants were similar to those of the corresponding Col+ donor DEC strains. It appears that the untypable colicins are novel and, thus, warrant further study. Colicin production by some of the DEC strains evaluated partly explains why they were insensitive to standard colicins in a previous study.

Animals↗
PubMed1998

Can advanced hemostatic parameters detect disseminated intravascular coagulation more accurately in patients with cirrhosis of the liver?

BACKGROUND: Laboratory diagnosis of disseminated intravascular coagulation (DIC) is difficult in patients with cirrhosis of the liver due to the complicated hemostatic changes of DIC. More recently, newer molecular hemostatic markers have been used to improve the diagnosis of DIC. This study evaluated the ability of the more advanced hemostatic tests to diagnose DIC in patients with cirrhosis of the liver. METHODS: A series of hemostatic tests and parameters including activated partial thromboplastin time (APTT), prothrombin time (PT), thrombin time (TT), factor VIII assay, antithrombin (AT) activity, fibrinogen, plasminogen, protamine sulfate test (PST), fibrin (ogen) degradation product (FDP), D-dimer, thrombin-antithrombin complex (TAT) (measured by modified antithrombin, ATM), euglobulin lysis test (ELT) and platelet count were performed in 51 patients with cirrhosis of the liver. A diagnosis of DIC was made according to the following parameters and criteria: a) platelets less than 80 x 10(9)/l; b) PT greater than 1.5, c) APTT greater than 1.3; d) TT greater than 24 sec; e) AT less than 60%; f) ATM greater than 14.7 ng/ml (normal, mean +/- 3 SD); g) fibrinogen less than 1.50 g/l; h) positive PST; i) D-dimer greater than 1.0 microgram/ml; j) FDP greater than 20 micrograms/ml; k) ELT less than 150 min; l) plasminogen less than 50%. DIC was diagnosed if six or more of the above items were present, and at least two of them were item (a) to (h), and at least two were item (g) to (l). RESULTS: Although eight patients had results that fitted the diagnostic criteria of DIC by using the more advanced tests, only two of them were diagnosed with DIC by conventional testing. The concentration of factor VIII in these eight patients did not markedly decrease. CONCLUSIONS: New tests are not necessary to improve the diagnosis of DIC in patients with cirrhosis of the liver.

Adult↗
PubMed1998

Immunoglobulin D multiple myeloma: a case report.

Immunoglobulin D (IgD) multiple myeloma is a rare disorder with a poor prognosis. We herein report a case of IgD myeloma presenting with renal failure and bicytopenia. A bone marrow biopsy specimen showed infiltration of homogeneous plasma cells, which stained positively for IgD and light chains. We review the literature and discuss the clinical manifestations, diagnosis and treatment strategy for this rare tumor.

Adult↗
PubMed1997

Fine structure of the murine leptin receptor gene: splice site suppression is required to form two alternatively spliced transcripts.

The fine structure of the murine leptin receptor gene (Lepr) is described. Duplicated ligand binding domains (conserved among cytokine receptors) are found in eight exons (coding exons 3 to 6 and 8 to 11). Thus, it is possible that a single leptin receptor molecule could have two functional ligand binding domains. The transmembrane region of Lepr is in coding exon 16 while the juxtamembrane JAK docking site is in coding exon 17. For all membrane-bound forms, the transcript must include 17 invariant exons and 1 alternatively spliced 3' terminal exon. The transcript encoding the soluble receptor (Re) includes 14 coding exons and an alternatively spliced 3' terminal exon. We have identified two splice variants (Rc and Re) for which there are no intervening sequences between the two final exons. This unusual juxtaposition of exons requires that splice donor sites at the 5' end of the respective terminal exons be ignored in the production of these splice variants. We suggest that splice site suppression is responsible for the formation of two of the alternatively spliced forms of the mouse Lepr gene. The juxtaposition of two coding exons separated by a consensus splice donor sequence is the structural substrate for this mode of alternative splicing. We present evidence that the Rc form is expressed in human tissues while the Re form, the soluble receptor, is not expressed.

Alternative Splicing↗
PubMed1997

Nitric oxide and cGMP regulate endothelial permeability and F-actin distribution in hydrogen peroxide-treated endothelial cells.

We have previously reported that hydrogen peroxide (H2O2) has a concentration-dependent effect on endothelial permeability and F-actin distribution. In the present study, we considered the involvement of endogenous production of nitric oxide (NO) in the indicated effect of H2O2. This was done by measuring endothelial permeability to sodium fluorescein (MW 376 Da, Na-F) and to different-sized fluorescein-isothiocynate-labeled dextrans (FITC-dextrans) and by staining F-actin with rhodamine-labeled phalloidin in cultured bovine aortic endothelial cells growing on filters. A low concentration of H2O2 (10(-5) M) had no effect on either dense peripheral bands of F-actin (DPBs) or permeability. When N-nitro-l-arginine methylester (l-NAME), an inhibitor of NO production, was coadministrated with 10(-5) M H2O2, DPBs were disrupted and the permeability to FITC-dextran 40 and FITC-dextran 70, but not to Na-F and FITC-dextran 20, was increased. Combining of 10(-5) M H2O2 with l-arginine, a substrate for nitric oxide synthase, caused an increase in DPBs and a decrease in permeability to FITC-dextran 40 and FITC-dextran 70. l-arginine or l-NAME alone had no effect on either F-actin structure or endothelial permeability. A 10-fold higher concentration of H2O2 caused a disruption of DPBs and an increase in permeability; this could be prevented by adding l-arginine. An analogue of cGMP, i.e., 8-Br-cGMP, maintained DPBs and abolished the increase in permeability induced by the treatment with either 10(-4) M H2O2 or a combination of H2O2 and l-NAME. These results suggest that the endogenous production of NO is involved in maintaining endothelial junctions in H2O2-treated cells and that this involvement occurs via a cGMP-dependent mechanism.

Actin Cytoskeleton↗
PubMed1997

The effects of acute and chronic protein depletion and accretion on plasma concentrations of insulin-like growth factor-1, fibronectin and total protein for ruminants nourished by intragastric infusion of nutrients.

The relationships of N input or protein status and the concentrations of serum insulin-like growth factor-1 (IGF-1), plasma fibronectin (FN) and total protein (TP) were examined in three experiments with steers and sheep nourished by intragastric infusion of nutrients. In Expt 1, three steers (340 kg live weight) were infused with three levels of volatile fatty acids (0, 300 and 600 kJ/kg metabolic weight (W0.75) per d) and six levels of casein (0, 200, 400, 650, 1500 and 2500 mg N/kg W0.75 per d). Each N treatment was imposed for 5 d. In Expts 2 and 3, five groups of sheep (about 35 kg live weight) were infused with casein at 500 mg N/kg W0.75 per d for 2 weeks followed by 1500, 500 or 50 mg N/kg W0.75 per d in Expt 2, and in Expt 3, with 100 mg N/kg W0.75 per d for 6 weeks or 10 mg N/kg W0.75 per d for 4 weeks. Non-protein energy was maintained constant at 500 kJ/kg W0.75 per d throughout. Daily N balance and total body N content at the end were measured, and protein status was defined as a percentage of cumulative N accretion or depletion in relation to the total body N content at maintenance. It was found that IGF-1 and FN responded rapidly and substantially to altered N input, and that when daily N input was maintained constantly at sub-maintenance, their continuous declines were related closely to progressive protein depletion in the sheep. Plasma TP concentration was independent of N input when N input was altered acutely in the steers, but declined significantly and gradually with severe, chronic body protein depletion in the sheep. Plasma content of TP in the sheep however reduced acutely with a reduction in N input. Plasma volume fell substantially over the first 2 weeks of protein depletion, compensating for the declines in TP content and maintaining TP concentration plateau. The possible implications of the changes in TP concentration and content (concentration x volume) to body protein loss in sheep are discussed.

Animal Nutritional Physiological Phenomena↗
PubMed1997

Mitomycin-C induced hemolytic uremic syndrome: a case report and literature review.

Hemolytic uremic syndrome spontaneously arises in a few patients with advanced cancer, but it is more commonly related to the use of certain chemotherapeutic agents. Mitomycin-C is, etiologically, the most common causative agent inducing hemolytic uremic syndrome, in a dose dependent manner. We report this syndrome, attributable to mitomycin-C at a cumulative dose of 40 mg/m2, in a gastric cancer patient. A 42-year-old female with stage III gastric cancer underwent radical gastrectomy and was given mitomycin-C at 10 mg/m2 intravenously every four weeks as adjuvant therapy. Hemolytic uremic syndrome was diagnosed three months after the last dose of mitomycin-C administration. The most prominent symptoms included pallor, hypertension and anasarca, with laboratory evidence of microangiopathic hemolytic anemia, azotemia and hyperkalemia. Her disease was progressive, but fortunately stabilized after staphylococcus column A dialysis. Her disease remained in remission for 24 months from the time of diagnosis, and then relapsed in the form of peritoneal carcinomatosis with partial intestinal obstruction.

Adenocarcinoma↗
PubMed1997

Phenotype of the obese Koletsky (f) rat due to Tyr763Stop mutation in the extracellular domain of the leptin receptor (Lepr): evidence for deficient plasma-to-CSF transport of leptin in both the Zucker and Koletsky obese rat.

The obese phenotypes of the diabetes (db) mouse and fatty fa) rat are due to functional null mutations of the leptin receptor (Lepr). The recessive mutation in the Koletsky (f) obese rat maps to the same genetic intervals as db and fa and fails to complement the fa mutation. Comparison of the sequence of brain Lepr cDNA from +/+ and f/f animals reveals a T2349A transversion resulting in a Tyr763Stop nonsense mutation in the gene just before the transmembrane domain. Virtual absence of Lepr mRNA in whole brain from f/f animals is consistent with the presence of a null mutation. The predicted reduced cerebrospinal fluid (CSF) transport of leptin in both f/f and fa/fa mutants is reflected in the approximately 10-fold lower ratio of CSF/plasma leptin concentration in the obese versus lean animals. However, equivalent CSF leptin concentration between lean and obese rats (fa/fa, f/f) indicates that leptin can enter the CSF through a non-Lepr-mediated mechanism, which may be saturated at normal physiological plasma leptin concentration.

Animals↗
PubMed1997

Serum responses to the combination of Epstein-Barr virus antigens from both latent and acute phases in nasopharyngeal carcinoma: complementary test of EBNA-1 with EA-D.

Elevated serum IgA to antigens of EBV is associated with nasopharyngeal carcinoma (NPC). We have tested 620 NPC sera by ELISA for the presence of antibodies to EBV-encoded DNA binding protein, EBV-specific DNA polymerase, early antigen-diffused (EA-D), EBV nuclear antigen 1 (EBNA-1), EBV-specific thymidine kinase, and BamHI Z fragment EBV replication antigen. Sensitivity of these proteins was in the range of 51.5-79.5% for IgA and 69.4-82.8% for IgG. The complementary use of EBNA-1 with EA-D, however, could increase the sensitivity significantly to 98.1%. Western blot analysis further showed that the combination of EBNA-1 and EA-D is most useful for the detection of NPC. This is the first report of using double biomarkers including EBV gene products from both latent and active infections. The results of this study suggest that EBV in NPC may not be latent alone and that the method may be valuable for the early detection, early treatment, and better survival rate of patients with NPC. Because the application of recombinant EBV protein in ELISA is cost-effective and feasible for mass screening, the method may be of worth for further clinical investigation.

Adult↗
PubMed1997

Leiomyosarcoma of the left atrium: a case report.

Primary malignant cardiac tumors are uncommon, and cardiac leiomyosarcoma is extremely rare. We reported a case of left atrial (LA) leiomyosarcoma with unusual clinical manifestations. A 28-year-old female presented with unknown cause of fever, body weight loss and anemia for two months. Echocardiography and magnetic resonance image study disclosed a 5 x 3 x 3.6 cm3 lobulated mass in the LA with invasion to its posterior wall. Histologic and immuno-histochemical studies of the resected specimen revealed a picture of leiomyosarcoma. The patient improved after surgical resection and post-operative chemotherapy. The literature was reviewed with a discussion of the clinical manifestations, diagnosis and treatment strategy of this rare tumor. Diagnosis of LA leiomyosarcoma is frequently delayed to make a very poor prognosis. Postoperative chemotherapy should be considered because of highly possible incomplete resection. However, an optimal treatment regimen remains unknown.

Adult↗
PubMed1997

Primary low grade B-cell lymphoma of colon mimicking inflammatory bowel disease: a case report.

Primary lymphoma of colon is rare in clinical practice and sometimes difficult to diagnose. We described a case of primary, low grade B-cell lymphoma of colon, whose clinical pictures were similar to inflammatory bowel disease. Although the colon mucosa showed diffuse infiltration of lymphocytes with lymphoepithelial lesions on endoscopic biopsy, immunohistochemical stains for B- and T-cell markers were negative. However, the diagnosis of lymphoma was established by positive findings on rearrangement of antigen receptor gene. Clinical symptom of blood-tinged diarrhea subsided after six courses of chemotherapy. Follow-up colonoscopy revealed normal colon mucosa. However, biopsy of colon mucosa still revealed mild proliferation of small lymphocytes. This case has drawn our attention that primary colonic lymphoma may clinically simulate inflammatory bowel disease, and gene rearrangement analysis might be helpful in the diagnosis of malignant lymphoma when traditional histological and immunohistochemical studies fail to provide a definite diagnosis.

Aged↗
PubMed1997

Corneal melting after avulsion of a Molteno shunt plate.

PURPOSE: We report a case of Molteno shunt avulsion after blunt trauma resulting in corneal melting. The implant's connecting tube had been placed above the superior rectus muscle. METHODS: Case report. RESULTS: After blunt trauma, the secondary plate of a double-plated Molteno implant became completely dislodged anteriorly onto the patient's cornea. The corneal tissue entrapped beneath the avulsed plate was found to have extensive melting requiring emergency explantation of the Molteno implant and corneal grafting. CONCLUSIONS: Corneal melting after Molteno shunt avulsion is a novel finding. Placing a double-plated Molteno implant's connecting tube under the superior rectus muscle might decrease the risk of shunt avulsion after trauma.

Adult↗
PubMed1997

Expression of DNA topoisomerase II alpha and multidrug resistance p-glycoprotein in acute leukemia.

BACKGROUND: Drug resistance is a major cause of treatment failure in acute leukemia. Overexpression of multidrug resistance gene and decreased activity of topoisomerase II alpha are suggested as two important mechanisms for this resistance. METHODS: We used immunohistochemical method to determine the expressions of both topoisomerase II alpha (topo II alpha) and p-glycoprotein (gp-170) in bone marrow biopsy specimens from 68 cases of acute leukemia. Patients were divided into four groups: (1) leukemia cells with high score for topo II alpha and negative for gp-170; (2) leukemia cells with high score for topo II alpha and positive for gp-170; (3) leukemia cells with low score for topo II alpha and negative for gp-170; and (4) leukemia cells with low score for topo II alpha and positive for gp-170. The clinical responses were then followed as routine, and the clinical correlation was evaluated by analysis of variance and Pearson Chi-Square test. RESULTS: The measure of the single parameter (either topo II alpha or gp-170 alone) did not show a significant difference in the overall survival. However, the complete response rate was much higher in the first group patients whose bone marrow reading score was high in topo II alpha and negative for gp-170 expression. Survival duration increased with the increase in the complete response rate. CONCLUSIONS: Combined parameters of topo II alpha and gp-170 are more useful than any individual parameter for the prognosis of acute leukemia.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1996

Phenotypes of mouse diabetes and rat fatty due to mutations in the OB (leptin) receptor.

Mice harboring mutations in the obese (ob) and diabetes (db) genes display similar phenotypes, and it has been proposed that these genes encode the ligand and receptor, respectively, for a physiologic pathway that regulates body weight. The cloning of ob, and the demonstration that it encodes a secreted protein (leptin) that binds specifically to a receptor (OB-R) in the brain, have validated critical aspects of this hypothesis. Here it is shown by genetic mapping and genomic analysis that mouse db, rat fatty (a homolog of db), and the gene encoding the OB-R are the same gene.

Animals↗
PubMed1996

Characterization of a response element in the 5'-flanking region of the avian (chicken) PTH gene that mediates negative regulation of gene transcription by 1,25-dihydroxyvitamin D3 and binds the vitamin D3 receptor.

Analysis of the 5'-flanking region of the avian (chicken) PTH (cPTH) gene has revealed a DNA segment between -74 and -60 that is analogous to the consensus sequence for the vitamin D3 response element (VDRE). The DNA segment consists of two imperfect direct repeats, GGGTCA and GGGTGT, which are separated by a 3-bp spacer. The functionality of the putative VDRE was verified by transfection studies in opossum kidney cells using plasmid constructs that contained various regions of the cPTH gene 5'-flanking sequence and promoter fused to the gene for chloramphenicol acetyl transferase (CAT). Likewise, negative regulation of gene transcription by 1,25-dihydroxyvitamin D3 [1,25-(OH)2D3] was detected when the cPTH VDRE was inserted immediately upstream from truncated forms of the cPTH or the SV40 early promoter. Using gel mobility shift assays, the cPTH VDRE was compared with the human osteocalcin (hOC) VDRE, which activates gene transcription in the presence of 1,25-(OH)2D3. With a partially purified nuclear extract from dog intestine, the two VDREs produced gel shift patterns that were remarkably similar, with the exception that the binding affinity for the hOC sequence was notably greater. Both VDREs produced two major bound complexes (B1 and B2), which could be completely abolished by the addition of an excess of unlabeled hOC VDRE or a monoclonal antibody specific for the VDR protein. Furthermore, similar protein:DNA complexes were observed when either the cPTH or hOC VDRE were incubated with a mixture of purified preparations of recombinant VDR and retinoid X receptor alpha proteins. Ethylation interference analysis showed that the base contacts made by complexes B1 and B2 with the cPTH VDRE were essentially the same and were restricted primarily to the two half-site sequences.

Animals↗
PubMed1996

Phenotype of fatty due to Gln269Pro mutation in the leptin receptor (Lepr).

The rat fatty (fa) mutation produces profound obesity of early onset caused by hyperphagia, defective nonshivering thermogenesis, and preferential deposition of energy into adipose tissue. Genetic mapping studies indicate that fa and diabetes (db) are homologous loci in the rat and mouse genomes, respectively. It has been shown that db alleles carry mutations in the Lepr (leptin receptor) gene. This paper describes a point mutation in the fatty allele of Lepr. A nucleotide substitution at position 880 (A-->C) causes an amino acid substitution at position 269 (Gln-->Pro). The mutation generates a novel Msp I site that cosegregates with fa in 1,028 meioses examined in obese F2 progeny from two crosses (Bnx13M and WKYx13M) and is still segregating in three rat colonies. PCR-based mutagenesis was used to introduce the fa mutation into the mouse Lepr cDNA. Transient transfection studies indicate that the mutant Lepr cDNA has greatly reduced binding of leptin (Lep) at the cell surface. These data are strong evidence that the single nucleotide substitution in the fa allele of Lepr (Leprfa) is responsible for the obese phenotype.

Amino Acid Sequence↗