Ultrasonographic localization and marking of a small recurrent thyroid papillary carcinoma.
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Aged↗
Biomedical subjects
H Yeh
Publications and source records attributed to H Yeh.
Use of cell-based therapies for modification of host immune responses.
The success of adoptive cellular therapy depends on the ability to select optimally or produce cells genetically with the desired antigenic specificity, and then induce cellular proliferation while preserving the effector function, engraftment, and homing abilities of the lymphocytes. Unfortunately, many previous clinical trials were carried out with adoptively transferred cells that were propagated in what are now understood to be sub-optimal conditions that impair the essential functions of the adoptively transferred cells. This article reviews some of the lessons and developments emerging from the past 20 years of adoptive immunotherapy trials and basic immunology regarding immunogenicity, T cell homeostasis, and the maintenance of tolerance and repertoire.
Adoptive Transfer↗
Performance of batch membrane reactor: Glycerol-3-phosphate synthesis coupled with adenosine triphosphate regeneration.
Glycerol-3-phosphate (G3P) was synthesized from glycerol using glycerol kinase (GK). This reaction requires adenosine triphosphate (ATP) and was coupled with the ATP regeneration reaction using acetate kinase (AK) in a batch-operated ultrafiltration hollow-fiber reactor. By taking into consideration the dynamic nature of the bioreactor performance under non-steady-state conditions, a model for the performance of a batch membrane reactor for G3P synthesis coupled with ATP regeneration was developed and studied. The simulation results showed good agreement with the experimental results. The simulation studies have provided some insight into the process dynamics of the coupled reactions in the reactor system studied. For the reactor operational model used, in which the enzymes are retained in the shell side and the substrates are also initially placed in the shell side, it was found that the substrate concentration in the lumen side increased to a level higher than that in the shell side, and a backdiffusion occurred from the lumen side to the shell side during reactor operation. The ratio of the reaction rate to diffusion rate goes through a sharp peak during the time that the direction of diffusion is reversed. For another reactor operational model, in which the substrates were initially placed in the lumen side and enzymes were retained in the shell side, it was found that the rate-controlling step between the reaction and diffusion was switched during the reactor operation. Initially, the reaction rate increased while the diffusion rate was high and the substrate concentrations increased in the shell side. The ratio of reaction rate to diffusion rate increased to a maximum and remained at a constant level as the diffusion rate decreased to a low level due to the nonlinear characteristics of mass transfer process. This study provides information that is useful for optimization of batch membrane enzyme reactor operation and for a fed-batch-type process with an intermittent feeding strategy for efficient use of substrates.
Acetate Kinase↗
Regulatory CD4(+)CD25(+) T cells in tumors from patients with early-stage non-small cell lung cancer and late-stage ovarian cancer.
Immunosuppression may contribute to the progression of cancer. In this study we assessed the structural and functional status of T cells from tumor specimens obtained from patients with early stage non-small cell lung cancer and late-stage ovarian cancer. Although some groups have described structural alterations in the TCR in patients with other malignancies, we did not observe decreased expression of the CD3zeta subunit in the tumor-associated T cells. However, increased percentages of CD4(+)CD25(+) T cells were observed in the non-small cell lung cancer tumor-infiltrating lymphocytes and ovarian cancer tumor-associated lymphocytes. Furthermore, these CD4(+)CD25(+) T cells were found to secrete transforming growth factor-beta, consistent with the phenotype of regulatory T cells. Despite a generalized expression of lymphocyte activation markers in the tumor-associated T-cell populations, the CD8(+) T cells expressed low levels of CD25. To determine whether expression of CD25 could be restored on the CD8 cells, tumor-associated T cells were stimulated with anti-CD3 and anti-CD28 monoclonal antibodies. After stimulation, nearly all of the CD8 T cells expressed CD25. Furthermore, despite the low levels of interleukin 2, IFN-gamma, and tumor necrosis factor-alpha secretion by the tumor-associated and peripheral blood T cells at baseline, stimulation with anti-CD3 and anti-CD28 monoclonal antibodies significantly increased the fraction of cells producing these cytokines. Thus, tumor-associated T cells from patients with early and late-stage epithelial tumors contain increased proportions of CD4(+)CD25(+) T cells that secrete the immunosuppressive cytokine transforming growth factor-beta. Furthermore, our results are consistent with previous reports showing impaired expression of CD25 on CD8(+) T cells in cancer patients. Finally, increased lymphocyte costimulation provided by triggering the CD28 receptor is able to increase CD25 expression and cytokine secretion in tumor-associated T cells. These observations provide evidence for the contribution of regulatory T cells to immune dysfunction in cancer patients.
CD3 Complex↗
Cancer incidence after childhood nasopharyngeal radium irradiation: a follow-up study in Washington County, Maryland.
A population from a hearing clinic in Washington County, Maryland, in 1943-1960 was followed to assess the risk of developing neoplasms from radium treatment of the nasopharynx for adenoid hypertrophy. Of the 2,925 subjects who attended the clinic, 904 received radium treatment. A nonconcurrent prospective study compared the cancer incidence among the irradiated persons with that among persons with other treatments. Seven brain tumor cases (three malignant and four benign) were identified in the irradiated group versus none in the nonirradiated group (relative risk = 14.8, 95% confidence interval: 0.76, 286.3). A nonsignificant excess risk of thyroid cancer was detected in the irradiated group based on two cases in the exposed group and one case in the nonexposed group (relative risk = 4.2, 95% confidence interval: 0.38, 46.6). Decreased risks of breast cancer, female genital cancers, and prostate cancer were observed among the irradiated individuals, although these deficits were not statistically significant individually. The decreased risk of sex hormone-related cancers in the irradiated group suggests possible radiation damage to the pituitary, with consequent reduction in pituitary hormone output and alterations in sexual and other hormonal development in early life. This hypothesis needs further evaluation.
Adenoids↗
The role of ERG (ets related gene) in cartilage development.
OBJECTIVE: Based on function and developmental fate, cartilage tissue can be broadly classified into two types: transient (embryonic or growth-plate) cartilage and permanent cartilage. Chondrocytes in transient cartilage undergo terminal differentiation into hypertrophic cells, induce cartilage-matrix mineralization, and eventually disappear and are replaced by bone. On the other hand, chondrocytes in permanent cartilage do not differentiate further, do not become hypertrophic, and persist throughout life at specific sites, including joints and tracheal rings. While many studies have described differences in structure, matrix composition and biological characteristics between permanent and transient cartilage, it is poorly understood how the fates of permanent and transient cartilage are determined. Previous studies demonstrated that chondrocytes isolated from permanent cartilage have the potential to express markers of the mature hypertrophic phenotype once grown in culture, suggesting that cell hypertrophy is an intrinsic property of all chondrocytes and must be actively silenced in permanent cartilage in vivo. These silencing mechanisms, however, are largely unknown. In this paper, we first review nature of chondrocytes in transient and permanent cartilages and then report the cloning and characterization of a novel variant of ets transcription factor chERG, hereafter called C-1-1, which might be involved in regulation of permanent cartilage development. DESIGN: For cloning of a novel variant of chERG (C-1-1), we isolated RNA from the cartilaginous femur or tibiotarsus of Day 17 chick embryos and processed it for reverse transcription-polymerase chain reaction (RT-PCR) with the primers from sequences upstream and downstream of the 81 and 72 bp segments alternatively-spliced in mammals. For investigation of function of chERG and C-1-1, we over-expressed chERG or C-1-1 in cultured chick chondrocytes or the developing limb of chick embryo using a retrovirus (RCAS) system, and examined the phenotype changes in the infected chondrocytes or the infected limb elements. RESULTS: C-1-1 is an alternative and novel variant lacking the 27 amino acids segment of chERG that has been reported previously. C-1-1 is preferentially expressed in developing articular cartilage, whereas chERG is preferentially expressed in growth plate cartilage. Growth of articular chondrocytes in culture was accompanied by decreasing C-1-1 expression after several passages, while expression of hypertrophic markers increased. Expression of C-1-1 in cultured chondrocytes inhibited cell hypertrophy, alkaline phosphatase activity, and cartilage matrix mineralization. In contrast, over-expression of chERG promoted chondrocyte maturation and mineralization. CONCLUSION: Our data demonstrate for the first time that chERG and C-1-1 play distinct roles in skeletogenesis and may have crucial roles in the development and function of transient and permanent cartilages.
Animals↗
Transcription factor ERG variants and functional diversification of chondrocytes during limb long bone development.
During limb development, chondrocytes located at the epiphyseal tip of long bone models give rise to articular tissue, whereas the more numerous chondrocytes in the shaft undergo maturation, hypertrophy, and mineralization and are replaced by bone cells. It is not understood how chondrocytes follow these alternative pathways to distinct fates and functions. In this study we describe the cloning of C-1-1, a novel variant of the ets transcription factor ch-ERG. C-1-1 lacks a short 27-amino acid segment located approximately 80 amino acids upstream of the ets DNA binding domain. We found that in chick embryo long bone anlagen, C-1-1 expression characterizes developing articular chondrocytes, whereas ch-ERG expression is particularly prominent in prehypertrophic chondrocytes in the growth plate. To analyze the function of C-1-1 and ch-ERG, viral vectors were used to constitutively express each factor in developing chick leg buds and cultured chondrocytes. We found that virally driven expression of C-1-1 maintained chondrocytes in a stable and immature phenotype, blocked their maturation into hypertrophic cells, and prevented the replacement of cartilage with bone. It also induced synthesis of tenascin-C, an extracellular matrix protein that is a unique product of developing articular chondrocytes. In contrast, virally driven expression of ch-ERG significantly stimulated chondrocyte maturation in culture, as indicated by increases in alkaline phosphatase activity and deposition of a mineralized matrix; however, it had modest effects in vivo. The data show that C-1-1 and ch-ERG have diverse biological properties and distinct expression patterns during skeletogenesis, and are part of molecular mechanisms by which limb chondrocytes follow alternative developmental pathways. C-1-1 is the first transcription factor identified to date that appears to be instrumental in the genesis and function of epiphyseal articular chondrocytes.
Alkaline Phosphatase↗
Enzymatic synthesis of cephalothin by penicillin G acylase*
Enzymatic synthesis of cephalothin from 7-aminocephalosporanic acid (7-ACA) and amide derivatives of 2-thienylacetic acid (2-TA) using penicillin G acylase (pen G acylase) was studied. Two amide derivatives of 2-TA namely 2-thienylacetamide (2-TAA) and 2-thienylacetohydroxamic acid (2-TAH) were used in this study. The main reason for choosing amide but not the methyl ester derivative of 2-TA for the enzymatic synthesis was to increase their solubilities in water. The solubility of 2-TA methyl ester (2-TAM), 2-TAA, and 2-TAH in aqueous solution is 8 +/- 0.05 mM, 87 +/- 0.75 mM and 120 +/- 1.65 mM, respectively. Enzymatic conversion of 2-TAH to cephalothin yielded side products but they were not found in the conversion of 2-TAA to cephalothin. The side products were derived from reactions between hydroxyamine and 7-ACA. The effects of pH, temperature, initial substrate concentrations and reaction time on the conversion of 2-TAA and 7-ACA to cephalothin were examined. The optimum reaction condition was determined at pH 6.5 and 10 approximately 15 degrees C. The best conversion yield of 72% was obtained when the initial concentration of 2-TAA and 7-ACA was at 0.4 M and 0.1 M, respectively. Furthermore, a one-step method was developed to purify cephalothin from the enzymatic reaction mixture with the purity of 91% and the recovery yield of 96%.
Journal Article↗
Hydroxyurea-induced cutaneous ulceration in older patients.
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Aged↗
Engineering tissue-specific expression of a recombinant adenovirus: selective transgene transcription in the pancreas using the amylase promoter.
Recombinant adenovirus accomplishes highly efficient gene transfer in vivo. Adenoviral vectors would be more attractive vehicles for gene therapy if transgene expression was inducible and restricted to the target tissue. In these studies, we hypothesized that selective transgene expression of a recombinant adenovirus could be accomplished by using a tissue-specific promoter of transcription. A replication-defective adenoviral vector was engineered to express the lacZ marker gene under control of the murine pancreatic amylase promoter. Expression of this vector occurred exclusively in the pancreas in neonatal and adult mice, while a similar vector with a constitutive promoter accomplished transgene expression in several organs. Within the adenoviral construct, the amylase promoter retained its ability to be induced by dexamethasone and insulin. This model will serve as a paradigm for selective and inducible adenoviral transgene expression.
Adenoviridae↗
Obliteration of a giant carotid aneurysm after extracranial-to-intracranial bypass surgery: case report.
BACKGROUND: Proximal arterial occlusion, with or without extracranial-to-intracranial (EC-IC) bypass, is frequently used as treatment for giant intracranial aneurysms that are unclippable. The authors report on a patient who had obliteration of a giant unruptured aneurysm of the right internal carotid terminus after undergoing an EC-IC bypass without proximal arterial ligation. METHODS: This 71-year-old woman presented with repeated right cerebral ischemia caused by a giant saccular aneurysm of the right internal carotid terminus. Direct surgical clipping of the aneurysm was not recommended because of the patient's age and because of the morphology of the aneurysm. She could not tolerate occlusion of the right internal carotid artery (ICA) and, therefore, first underwent an EC-IC bypass. Four weeks later, she returned to undergo a balloon occlusion of the right ICA proximal to the aneurysm. RESULTS: The right distal ICA and aneurysm were found to be spontaneously thrombosed. At 2-year follow-up, the aneurysm was shown to be completely obliterated on the magnetic resonance imaging scans. CONCLUSIONS: The authors conclude that hemodynamic changes in the blood flow of the parent artery after EC-IC bypass caused this occurrence.
Aged↗
The XPB and XPD DNA helicases are components of the p53-mediated apoptosis pathway.
The molecular pathway of p53-dependent apoptosis (programmed cell death) is poorly understood. Because p53 binds to the basal transcription-repair complex TFIIH and modulates its DNA helicase activities, we hypothesized that TFIIH DNA helicases XPB and XPD are members of the p53-mediated apoptotic pathway. Whereas transfer of a wild-type p53 expression vector by microinjection or retroviral infection into primary normal human fibroblasts resulted in apoptosis, primary fibroblasts from individuals with xeroderma pigmentosum (XP), who are deficient in DNA repair and have germ-line mutations in the XPB or XPD gene, but not in the XPA or XPC gene, have a deficiency in the apoptotic response. This deficiency can be rescued by transferring the wild-type XPB or XPD gene into the corresponding mutant cells. XP-D lymphocytes also have a decreased apoptotic response to DNA damage by adriamycin, indicating a physiologically relevant deficiency. The XP-B or XP-D mutant cells undergo a normal apoptotic response when microinjected with the Ich-L, and ICE genes. Analyses of p53 mutants and the effects of microinjected anti-p53 antibody, Pab421, indicate that the carboxyl terminus of p53 may be required for apoptosis. Direct microinjection of the p53 carboxy-terminal-derived peptide (amino acid residues 319-393) resulted in apoptosis of primary normal human fibroblasts. These results disclose a novel pathway of p53-induced apoptosis.
Apoptosis↗
Rat kidney glutathione S-transferase 1 subunits have C-terminal truncations.
Cytosolic glutathione S-transferases (GSTs) from rat kidneys were purified by a combination of glutathione and S-hexylglutathione affinity columns. The isolated GSTs were subjected to reverse-phase HPLC and electrospray MS analysis. The major GST isoenzymes expressed in kidney are subunits 1, 2, 7 and 8. GST 1',3 and 4 are expressed in minor amounts. GST 10 is barely detectable in the male kidney cytosol. The molecular masses of these rat kidney GST subunits were determined by MS. The values obtained for subunits 1', 2, 3, 4, 7, 8 and 10 are identical with those obtained for rat liver GSTs. Rat kidney GST 1 consists of three polypeptides, with molecular masses of 25517, 25372 and 24982 Da. Results from peptide mapping, MS and amino-acid-sequencing analyses indicate that the major components were generated by deleting the C-terminal phenylalanine (24982 Da) and the C-terminal IFKF tetrapeptide (25372 Da) from the GST 1 subunit, respectively. The 1-chloro-2,4-dinitrobenzene-conjugating and peroxidase activities of kidney GST 1 are substantially lower than for its counterpart from rat liver. In addition, rat kidney GST 1 has an arginine and a valine residue at positions 151 and 207 respectively. The results are in contradiction with the SWISS-PROT and GenBank rat liver GST 1 cDNA-sequencing data, which give a lysine and a methionine at the corresponding positions. Further analyses indicate that rat liver GST 1 also has a C-terminal phenylalanine deletion, and an arginine and a valine residue at positions 151 and 207 respectively. However, the C-terminal-tetrapeptide-deleted form was not observed for rat liver GST 1.
Amino Acid Sequence↗
Abrogation of p53-induced apoptosis by the hepatitis B virus X gene.
The p53 tumor suppressor gene product is a transcriptional transactivator and a potent apoptotic inducer. The fact that many of the DNA tumor virus oncoproteins bind to p53 and affect these p53 functions indicates that this interaction is an important step in oncogenic transformation. We and others have recently demonstrated that the hepatitis B virus oncoprotein, HBx, can form a complex with p53 and inhibit its DNA consensus sequence binding and transcriptional transactivator activity. Using a microinjection technique, we report here that HBx efficiently blocks p53-mediated apoptosis and describe the results of studies exploring two possible mechanisms of HBx action. First, inhibition of apoptosis may be a consequence of the failure of p53, in the presence of HBx, to upregulate genes, such as p21WAF1, Bax, or Fas, that are involved in the apoptotic pathway. Data consistent with this hypothesis include HBx reduction of p53-mediated p21WAF1 expression. Alternatively, HBx could affect p53 binding to the TFIIH transcription-nucleotide excision repair complex as HBx binds to the COOH terminus of p53 and inhibits its binding to XPB or XPD. Binding of p53 to these constituents of the core TFIIH is a process that may be involved in apoptosis. Because the HBx gene is frequently integrated into the genome of hepatocellular carcinoma cells, inhibition of p53-mediated apoptosis by HBx may provide a clonal selective advantage for hepatocytes expressing this integrated viral gene during the early stages of human liver carcinogenesis.
Apoptosis↗
Structure of the elastin gene.
The isolation and characterization of cDNAs encompassing the full length of chicken, cow, rat and human elastin mRNA have led to the elucidation of the primary structure of the respective tropoelastins. Large segments of the sequence are conserved but there are also considerable variations which range in extent from relatively small alterations, such as conservative amino acid substitutions, to variation in the length of hydrophobic segments and largescale deletions and insertions. In general, smaller differences are found among mammalian tropoelastins and greater ones between chicken and mammalian tropoelastins. Although only a single elastin gene is found per haploid genome, the primary transcript is subject to considerable alternative splicing, resulting in multiple tropoelastin isoforms. Functionally distinct hydrophobic and cross-link domains of the protein are encoded in separate exons which alternate in the gene. The introns of the human gene are rich in Alu repetitive sequences, which may be the site of recombinational events, and there are also several dinucleotide repeats, which may exhibit polymorphism and, therefore, be effective genetic markers. The 5' flanking region is G+C rich and contains potential binding sites for numerous modulating factors, but no TATA box or functional CAAT box. The basic promoter is contained within a 136 bp segment and transcription is initiated at multiple sites. These findings suggest that the regulation of elastin gene expression is complex and takes place at several levels.
Alternative Splicing↗
p53 modulation of TFIIH-associated nucleotide excision repair activity.
p53 has pleiotropic functions including control of genomic plasticity and integrity. Here we report that p53 can bind to several transcription factor IIH-associated factors, including transcription-repair factors, XPD (Rad3) and XPB, as well as CSB involved in strand-specific DNA repair, via its C-terminal domain. We also found that wild-type, but not Arg273His mutant p53 inhibits XPD (Rad3) and XPB DNA helicase activities. Moreover, repair of UV-induced dimers is slower in Li-Fraumeni syndrome cells (heterozygote p53 mutant) than in normal human cells. Our findings indicate that p53 may play a direct role in modulating nucleotide excision repair pathways.
Adenosine Triphosphatases↗
Structure of the human gene encoding the associated microfibrillar protein (MFAP1) and localization to chromosome 15q15-q21.
Microfibrils with a diameter of 10-12 nm, found either in association with elastin or independently, are an important component of the extracellular matrix of many tissues. To extend our understanding of the proteins composing these microfibrils, the cDNA and gene encoding the human associated microfibril protein (MFAP1) have been cloned and characterized. The coding portion is contained in 9 exons, and the sequence is very homologous to the previously described chick cDNA, but does not appear to share homology or domain motifs with any other known protein. Interestingly, the gene has been localized to chromosome 15q15-q21 by somatic hybrid cell and chromosome in situ analyses. This is the same chromosomal region to which the fibrillin gene, FBN1, known to be defective in the Marfan syndrome, has been mapped. MFAP1 is a candidate gene for heritable diseases affecting microfibrils.
Amino Acid Sequence↗
Hepatitis B virus X protein inhibits p53 sequence-specific DNA binding, transcriptional activity, and association with transcription factor ERCC3.
Chronic active hepatitis caused by infection with hepatitis B virus, a DNA virus, is a major risk factor for human hepatocellular carcinoma. Since the oncogenicity of several DNA viruses is dependent on the interaction of their viral oncoproteins with cellular tumor-suppressor gene products, we investigated the interaction between hepatitis B virus X protein (HBX) and human wild-type p53 protein. HBX complexes with the wild-type p53 protein and inhibits its sequence-specific DNA binding in vitro. HBX expression also inhibits p53-mediated transcriptional activation in vivo and the in vitro association of p53 and ERCC3, a general transcription factor involved in nucleotide excision repair. Therefore, HBX may affect a wide range of p53 functions and contribute to the molecular pathogenesis of human hepatocellular carcinoma.
Cell Line↗