Biomedical subjects

T C Liu

Publications and source records attributed to T C Liu.

At least 109 records · Page 6Linked to original sources

PubMed1991

Facial nerve neurilemmoma: report of four cases.

Four cases of facial nerve neurilemmoma are reported. Hearing loss was the initial symptom in all four of these patients, and among them, one had facial palsy before the operation. Physically, a bulging mass underneath the skin in the posteroinferior part of the ear canal was found in all of these patients. Excision of the tumor with nerve graft or hypoglossal-facial crossover was done in three of the patients. Postoperatively, they had fair facial nerve function with no tumor recurrence. The other case had excision only, and the tumor recurred after the operation.

Adult↗

PubMed1991

Erythropoietin levels and inhibition of erythropoiesis in end-stage renal failure.

Anaemia of chronic renal failure is multifactorial. Twenty-one patients with end-stage renal disease (ESRD) and 21 normal subjects were studied to determine the significance of serum erythropoietin levels and erythropoiesis inhibition in the aetiology of renal anaemia. Serum erythropoietin levels and erythropoiesis inhibition were measured by determining the incorporation of labelled-thymidine into the DNA of rabbit bone marrow cells. The mean haemoglobin concentration was 9.0 +/- 0.5 g/dl (mean +/- SEM) in ESRD and 14.4 +/- 0.4 g/dl in normal controls. Serum erythropoietin levels (99.9 +/- 17.9 mU/ml in ESRD vs 74.9 +/- 9.7 mU/ml in normal controls) and inhibition of erythropoiesis (252 +/- 28.9 in ESRD vs 186.2 +/- 19.4 in normal controls) were not significantly different in both groups. However, erythropoiesis inhibition had a significant correlation with the degree of anaemia (p less than 0.01). The results suggest that erythropoiesis inhibition play a significant role in the pathogenesis of renal anaemia.

Adult↗

PubMed1991

Lymphocyte changes in secondary dengue fever: use of the Technicon H*1 to monitor progress of infection.

Secondary dengue fever as dengue hemorrhagic fever or dengue shock syndrome is a potentially fatal complication of an infection that presents with few clinical signs that help in the diagnosis. Previous workers have reported the value of buffy coat determinations of atypical lymphocytes as an aid to the diagnosis. We report here the use of an automated white blood cell differential counter, the Technicon H*1 in the monitoring of the atypical lymphocyte count as a measure of the progress of the infection in a retrospective study of serial full blood counts in 45 serologically confirmed patients. Technicon H*1 'basophil' and large unstained cell counts and manual atypical lymphocyte counts rose in tandem with the drop in platelets and decreased when the platelets recovered. In a sub-study, the atypical lymphocytes were immunophenotyped and found to be predominantly derived from T lymphocytes. We conclude that the Technicon H*1 is a useful monitor of the activity of the infection in dengue hemorrhagic fever.

Basophils↗

PubMed1991

Immunophenotypic characterisation of monocytoid differentiation markers in acute non-lymphoblastic leukaemias.

The FAB classification of acute non-lymphoblastic leukaemias has been shown to have some clinical use in the prognostication of patient survival. ANLL with monocytoid features (M4, M5) fare worse than those which are predominantly myeloblastic (M1, M2). Classification is, however, sometimes difficult if non-specific esterase activity is not strongly expressed. Monoclonal antibody characterisation of myeloid differentiation antigens may be of some use as a supplementary aid. We immunophenotyped the blast cells from 26 cases for HLA-Dr, CD14 (Mo2, My4), CD13 (My17) and CD33 (My9) expression using the APAAP method. A combination of CD14 and CD33 used together was useful in differentiating myeloblastic from monocytoid acute non-lymphoblastic leukaemias. We conclude that the use of surface markers is a useful adjunct to the diagnostic means presently available.

Antibodies, Monoclonal↗

PubMed1990

17-beta-estradiol potentiates luteinizing hormone glycosylation and release induced by veratridine, diacylglycerol, and phospholipase C in rat anterior pituitary cells.

We determined the effect of 17 beta-estradiol (E2) on synthesis and release of luteinizing hormone (LH) induced by drugs which activate intracellular signal transduction mechanisms in rat anterior pituitary cells. Cells were pretreated with E2 (6 x 10(-10) M) or diluent for 24 h, then washed and incubated for 4 h with E2 or diluent, respectively, in the presence or absence of drugs. LH translation and glycosylation were monitored by measuring incorporation of [14C]alanine and [3H]glucosamine, respectively, into total (medium plus cells) immunoprecipitable LH. Immunoreactive LH (IRLH) was measured by radioimmunoassay. Gonadotropin-releasing hormone (GnRH, 1 nM), veratridine (5 microM), L-alpha-1,2-dioctanoyl glycerol (C8, 200 microM), and phospholipase C (PLC, 0.24 U/ml) all increased (p less than 0.01) medium IRLH, [3H]glucosamine-LH, and [14C]alanine-LH, and total [3H]glucosamine-LH in both E2- and diluent-treated cells. Total IRLH or [14C]alanine-LH were not increased by any treatment. E2 alone slightly increased (p less than 0.05) basal medium IRLH and [3H]glucosamine-LH. The stimulatory effects of E2 on basal medium [14C]alanine-LH and total [3H]glucosamine-LH were inconsistent. E2 potentiated (p less than 0.01) the effects of veratridine, C8, PLC, and GnRH on medium IRLH, and medium and total [3H]glucosamine-LH. E2 also potentiated (p less than 0.01) the effects of veratridine, PLC, and GnRH, but not of C8, on medium [14C]alanine-LH. In contrast, E2 did not increase either precursor uptake or incorporation of precursor into total protein in the presence of any secretagogue.(ABSTRACT TRUNCATED AT 250 WORDS)

Alanine↗

PubMed1990

Detection of beta-globin gene from single hairs.

DNA can be extracted from hair shafts and hair roots. The content of DNA in hairs is usually limited: the root end of hairs may contain 0.5 micrograms DNA and shed hairs contain less than 10 ng DNA. DNA analysis with restriction fragment length polymorphism (RFLP) requires microgram amounts of DNA. Such DNA cannot be obtained from such samples as single hairs or blood stains. Even with a little amount of DNA, specific genes of DNA can be greatly amplified to more than 10(6)-fold in vitro by polymerase chain reaction (PCR). We extracted the DNA from a half, 1, and 2 hair roots and 4 hair shafts and amplified the DNA with primer pairs (5'-GCACCATTCTAAAGAATAAC-3', 5'-GGATTGTAGCTGCTATTAGC-3') of the beta-globin gene, covering part sequences of the IVS-2 region by using the polymerase chain reaction for 50 cycles. The electrophoresis of the PCR product revealed a 131 base pairs band. Finally, we hybridized the PCR product with an IVS-2 probe (5'-GGGTTAAGGCAATAGCAAT-3'). A fragment of the IVS-2 extending from nucleotide 612 to 742 of the beta-globin gene can be demonstrated in the slot blot filter of hair roots and hair shafts, but not in the 1 microgram of blood which was not amplified by PCR. Detection of the beta-globin gene from single hairs by using the PCR may be useful for the diagnosis of thalassemia from single hairs.

Base Sequence↗

PubMed1990

Lymph node blast crisis of chronic myelogenous leukemia. One case report.

We present a patient with philadelphia chromosome (ph')-positive CML with extramedullary blast crisis in the lymph nodes before the bone marrow blast crisis. The morphological and cytochemical studies of lymph node touch preparation, and cytogenetic studies of lymph node tissue confirmed the extramedullary lymphoid blast transformation of CML, while the bone marrow continued to show the chronic phase of CML. When we changed our treatment to use Vincristine-Prednisolone therapy, the lymphadenopathy disappeared gradually. This case shows that the clinical and prognostic features of extramedullary disease can strongly affect disease acceleration in CML, and the therapy should be changed promptly. Besides, cytogenetic study of extramedullary tumor tissue in CML can be useful for accurate diagnosis.

Aged↗

PubMed1989

Characterization of cDNAs encoding human pyruvate dehydrogenase alpha subunit.

A cDNA clone (1423 base pairs) comprising the entire coding region of the precursor form of the alpha subunit of pyruvate dehydrogenase (E1 alpha) has been isolated from a human liver cDNA library in phage lambda gt11. The first 29 amino acids deduced from the open reading frame correspond to a typical mitochondrial targeting leader sequence. The remaining 361 amino acids, starting at the N terminus with phenylalanine, represent the mature mitochondrial E1 alpha peptide. The cDNA has 43 base pairs in the 5' untranslated region and 210 base pairs in the 3' untranslated region, including a polyadenylylation signal and a short poly(A) tract. The nucleotide sequence of human liver E1 alpha cDNA was confirmed by the nucleotide sequences of three overlapping fragments generated from human liver and fibroblast RNA by reverse transcription and DNA amplification by the polymerase chain reaction. This consensus nucleotide sequence of human liver E1 alpha cDNA resolves existing discrepancies among three previously reported human E1 alpha cDNAs and provides the unambiguous reference sequence needed for the characterization of genetic mutations in pyruvate dehydrogenase-deficient patients.

Amino Acid Sequence↗

PubMed1989

Differential actions of arachidonic acid and melittin on luteinizing hormone release and synthesis.

We studied the actions of arachidonic acid (AA) on luteinizing hormone (LH) release versus synthesis (translation or glycosylation) by cultured rat anterior pituitary cells. Monolayer cells were incubated for 3-4 h with secretagogues (AA, melittin, gonadotropin-releasing hormone; GnRH) which either increase endogenous AA levels or release AA. LH translation and glycosylation were monitored by measuring the incorporation of [14C]alanine and [3H]glucosamine, respectively, into total (cell plus medium) immunoprecipitable LH. Immunoreactive (IR) LH was measured by radioimmunoassay. Nonlytic doses of AA increased (p less than 0.01) IR-LH release without increasing total [3H]glucosamine-LH, [14C]alanine-LH, or [3H]glucosamine-protein. AA either had no effect or slightly increased (p less than 0.05) [3H]glucosamine uptake, but decreased (p less than 0.01) [14C]alanine uptake and incorporation into total [14C]alanine protein. AA at 250 microM lysed cells, thus increasing medium IR-LH and decreasing (p less than 0.01) [3H]glucosamine and [14C]alanine uptake and incorporation into total LH and protein. Melittin, which releases AA by activating phospholipase A2 (245 and 490 nM), increased medium IR-LH (p less than 0.01) without affecting any other parameter measured. GnRH at 1 nM enhanced (p less than 0.01) both LH (IR-LH, [3H]glucosamine-LH and [14C]alanine-LH) release and total [3H]glucosamine-LH, but had no effect on total [14C]alanine-LH. In summary, AA and melittin at doses which stimulated LH release did not stimulate either LH glycosylation or translation. This suggests that increased LH release by nonspecific secretagogues is not necessarily accompanied by increased LH glycosylation or translation.

Alanine↗

PubMed1989

Giant cell tumors of bone. An immunohistochemical study.

Immunohistochemical study of giant cell tumor of bone (GCT) was carried out utilizing a panel of monoclonal antibodies including those against lysozyme, alpha-antichymotrypsin (AACT), vimentin (Vim), M718, HLA-DR, S-100 protein, epithelial membrane antigen (EMA), leukocyte common antigen (LCA), KB90, factor VIII related antigen (F VIII) against stromal cells and giant cells in 20 cases of GCT, with one case of prolonged continuously cultured cells GCT (GT 15). The results showed that stromal cells could be divided into two subgroups. Mesenchymal stromal cells labelled only with vimentin and were regarded as being derived from undifferentiated mesenchymal cells of bone marrow, while macrophage-like stromal cells labelled with antigens and were found to be present in mononuclear phagocytes. We believe this to be the first report that some stromal cells reacted positively with S-100 protein. Multinucleated giant cells were AACT and M718 positive, indicating their close relationship to macrophage-like stromal cells. The prolonged cultured cells accepted labelling with vimentin only indicating that all macrophage-like stromal cells disappeared after several subcultures and the only cells that could continue to be subcultured were the mesenchymal stromal cells.

Bone Neoplasms↗

PubMed1989

Circulating immune complexes in patients with hematologic diseases.

Circulating immune complexes (CIC) were measured by C1q-solid phase method in ninety-five patients with various hematologic diseases. The results showed significantly higher CIC levels in patients with acute myelocytic leukemia, chronic myelocytic leukemia, aplastic anemia and idiopathic thrombocytopenic purpura (ITP) than CIC levels in normal controls. However, there was no significant difference in such levels in patients with acute lymphocytic leukemia, non-Hodgkin's lymphoma and multiple myeloma when compared to normal controls. In this study, the level of CIC did not relate to prognosis for patients with non-Hodgkin's lymphoma. The findings demonstrated that a high level of CIC in patients with ITP usually responded poorly to steroid treatment. Other immunosuppressive agents were indicated in these cases. Therefore, the CIC level may serve as a therapeutic guide for the treatment of patients with ITP.

Antigen-Antibody Complex↗

PubMed1989

Light- and electron-microscopic study of M. leprae-infected armadillo nerves.

Lesions in peripheral nerves of armadillos experimentally infected with Mycobacterium leprae were studied by light- and electron-microscopy. Bacilli could be found clearly inside axons of unmyelinated nerve fibers. Heavily bacillated Schwann cells were seen embracing unmyelinated axons with interrupted cytoplasmic membranes. This indicated the initiation of rupture of those cells which were responsible for the liberation of bacilli into the axons. The nerve lesions were divided into three grades according to their severity: grade I showed lesions focalized in the perineurium; grade II lesions were scattered inside nerve tissue; and in grade III lesions the nerve tissues were diffusely affected. No regressive changes, such as fibrosis or scar formation, were seen in the nerve lesions. Bacillated macrophages were not as foamy as those of human lesions, indicating that these bacillated cells were younger or more easily disrupted with a higher turnover than the cells in human lesions. This would promote the spread of lesions in armadillos, and would explain the less foamy appearance of the cells. We found bacilli inside lymphatics surrounding the nerves, substantiating the opinion that lesions spread to peripheral nerves not only by a hematogenous route but also by the lymphatics.

Animals↗

PubMed1989

Spontaneous pneumothorax following chemotherapy for malignant thymoma with pulmonary metastasis: report of a case.

Spontaneous pneumothorax is a rare complication in both primary and metastatic pulmonary neoplasms. Occasionally, pneumothorax is associated with chemotherapy of pulmonary malignancies. Pneumothorax after chemotherapy has been reported only in cases with osteogenic sarcoma, synovial sarcoma, fibrosarcoma, germinal tumors, and lymphoma with lung metastasis. We report a case of a patient with malignant thymoma who suffered from lung metastasis after radiation and adjuvant chemotherapy from lung metastasis after radiation and adjuvant chemotherapy (cyclophosphamide, adriamycin, and cis-platinum). A chest X-ray taken 2 days after chemotherapy showed bilateral pneumothorax, which was resolved with conservative treatment. The pneumothorax in this patient is believed to have been caused by the rupturing of the tumor into the pleural cavity and the bronchi.

Adult↗

PubMed1988

Nucleotide sequence of a cDNA for the dihydrolipoamide acetyltransferase component of human pyruvate dehydrogenase complex.

Deoxynucleotide sequencing of a cDNA for the dihydrolipoamide acetyltransferase (PDC-E2) component of human pyruvate dehydrogenase complex (PDC) revealed an open reading frame of 1848 base pairs corresponding to a leader sequence of 54 amino acids and a mature protein of 561 amino acids (59,551 Da). Both an amino-terminal lipoyl-bearing domain and a carboxy-terminal catalytic domain are present in the deduced amino acid sequence. The lipoyl-bearing domain contains two repeating units of 127 amino acids, each harboring one lipoic acid-binding lysine. Thus, mammalian PDC-E2 differs as to the number of lipoic acid-binding sites from other dihydrolipoamide acyltransferases in both prokaryotic and eukaryotic organisms.

Acetyltransferases↗

PubMed1988

Actions of 17 beta-estradiol on gonadotropin release induced by drugs that activate intracellular signal transduction mechanisms in rat anterior pituitary cells.

We studied the effects of 17 beta-estradiol (E2) on luteinizing hormone (LH) and follicle-stimulating hormone (FSH) release induced by drugs that activate different intracellular signal transduction mechanisms in rat anterior pituitary cells. Cells were pretreated with E2 (6 x 10(-10) M) or diluent for 24 h. Then, both E2- and diluent-pretreated cells were incubated for 4 h with E2 or diluent, respectively, with or without drugs, and in the presence or absence of gonadotropin-releasing hormone (GnRH). Media were assayed for LH and FSH by radioimmunoassays. E2 treatment had no effect on basal FSH release, but occasionally stimulated basal LH release. Phospholipase C (PLC), L-alpha-1,2-dioctanoyl glycerol (C8), veratridine, 8-bromo-cyclic adenosine 3',5'-monophosphate (8-Br-cAMP), melittin (a phospholipase A2 [PLA2] activator), arachidonic acid, PLA2, and GnRH all stimulated LH and FSH release in both E2- and diluent-treated cells. E2 treatment increased both LH and FSH release induced by GnRH, PLC, C8, veratridine, and 8-Br-cAMP, but not by melittin, arachidonic acid, and PLA2. Neither C8, PLA2, nor arachidonic acid in combination with a maximal dose of GnRH had additive effects on either LH or FSH release, whereas melittin increased the maximal response to GnRH in both E2- and diluent-treated cells. The effects of veratridine and 8-Br-cAMP depended on dose of GnRH and presence or absence of E2. These results suggest that E2 augments stimulus-coupled gonadotropin release by interacting with the Ca2+-, and/or diacylglycerol-, and cAMP-activated pathways, but not with the arachidonic acid-activated pathway.

8-Bromo Cyclic Adenosine Monophosphate↗

PubMed1988

The treatment of acute polyradiculoneuritis with respiratory paralysis.

This paper reports 504 cases admitted with acute polyradiculoneuritis (AP) to Beijing Children's Hospital from 1975 through 1984. 343 of the 504 cases (68.1%) with AP had respiratory paralysis and in 198/504 (39.3%), tracheotomy was performed. In this study, none of the patients received steroids. We attempted to assess the grades of respiratory paralysis and established the criteria for tracheotomy. We also must perform the following procedures: 1) Artificial ventilation must be used correctly, 2) The secretion should be aspirated regularly in order to maintain a clear airway, 3) Sterilization must be strictly conducted to prevent cross infection. As a result, of 504 cases with AP 9 died, the mortality rate being 1.79%. The study suggests tracheotomy should be performed early and it is one of the most important procedures in the treatment of AP with respiratory paralysis.

Acute Disease↗

PubMed1988

Molecular analysis of hemoglobin H disease in Taiwan.

The molecular basis of seven Chinese patients in Taiwan with hemoglobin H disease was investigated and was found to be heterogeneous in the mutation type. They were alpha-thalassemia-1 mutation combined with hemoglobin Constant Spring, an undetermined nondeletion form of alpha-thalassemia and a deletion form of alpha-thalassemia-2 mutations. The alpha-thalassemia-1 mutation was shown to be the --SEA type I haplotype.

Adult↗

PubMed1987

Stimulation by phorbol ester and diacylglycerol of luteinizing hormone glycosylation and release by rat anterior pituitary cells.

We studied the effects of protein kinase C (PKC) activators on LH glycosylation and release and the effect of 17 beta-estradiol on PKC activator-induced LH release. Rat anterior pituitary cells were incubated for 4 h with diluent, GnRH, and the PKC activators, phorbol 12-myristate 13-acetate (PMA), L-alpha-1,2-dioctanoyl glycerol (C8), and 1-oleoyl-2-acetyl-glycerol. LH translation and glycosylation were monitored by measuring incorporation of [14C]alanine ([14C]A) and [3H]glucosamine ([3H]GA), respectively, into total (medium + cell) immunoprecipitable LH. Immunoreactive LH (IRLH) was measured by RIA. PMA (10(-9) M) and 1-oleoyl-2-acetyl-glycerol (50-200 microM) had no significant effects. PMA at 10(-7) M elevated (P less than 0.01) medium IRLH, medium and total [3H]GA-LH, and medium but not total [14C]A-LH. PMA at 10(-7) M increased (P less than 0.01) uptake and incorporation of [3H]GA, but not [14C]A, into total pituitary protein. C8 increased both medium IRLH and total [3H]GA-LH (P less than 0.01) without altering total [14C]A-LH. Two hundred micromolar C8 increased medium concentrations of [3H]GA-LH (P less than 0.01) and [14C]A-LH (P less than 0.05). C8 (50-200 microM) had no detectable effects on uptake and incorporation of precursors into protein. GnRH (1 nM) enhanced (P less than 0.01) both medium IRLH and total [3H]GA-LH, but had no effect on total [14C]A-LH. Pretreatment of pituitary cells with 17 beta-estradiol (6 X 10(-10) M) greatly enhanced LH release induced by C8. In conclusion, PMA and C8, like GnRH, stimulated both LH glycosylation and release. These results suggest that PKC may regulate both LH release and glycosylation and may be important in estrogen modulation of LH release.

Animals↗