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Leighton SE, Teo JG, Leung SF, Cheung AY, Lee JC, van Hasselt CA. Prevalence and prognostic significance of tumor-associated tissue eosinophilia in nasopharyngeal carcinoma. Cancer 1996; 77:436-40. [PMID: 8630949 DOI: 10.1002/(sici)1097-0142(19960201)77:3<436::aid-cncr3>3.0.co;2-i] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
BACKGROUND Tumor-associated tissue eosinophilia (TATE) has been associated with an improved prognosis in a variety of neoplasms. METHODS Diagnostic biopsy specimens from 96 patients with nasopharyngeal carcinoma (NPC) were reviewed for the presence of TATE by an observer blinded to the patients' clinical histories. Comparisons between patients with and without TATE with respect to the probabilities of local recurrence, distant metastasis, and survival were performed using the log rank test on Kaplan-Meier product-limit estimates and the Cox proportional hazards model. RESULTS The prevalence of TATE in these patients was 32%, and was not significantly associated with local recurrence, distant metastasis, or survival. CONCLUSIONS These results are discordant with those of studies in other tumor models, although comparison is hampered by varying definitions of TATE. The differing results may be due to variations in the degree of activation of the eosinophils present in TATE in different tumors.
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Cheung AY, Wang H, Wu HM. A floral transmitting tissue-specific glycoprotein attracts pollen tubes and stimulates their growth. Cell 1995; 82:383-93. [PMID: 7634328 DOI: 10.1016/0092-8674(95)90427-1] [Citation(s) in RCA: 257] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Pollen tubes elongate directionally in the extracellular matrix of pistil tissues to transport the male gametes from the apically located stigma to the basally located ovary for fertilization. The molecular mechanisms underlying directional pollen tube growth in the pistil are poorly understood. We have purified a glycoprotein, TTS, from tobacco stylar transmitting tissue, which supports pollen tube growth between the stigma and the ovary. TTS proteins belong to the arabinogalactan protein family, and they polymerize readily in vitro in a head-to-tail fashion into oligomeric forms. TTS proteins stimulate pollen tube growth in vitro and attract pollen tubes grown in a semi-in vivo culture system. In vivo, the pollen tube growth rate is reduced in transgenic plants that have significantly reduced levels of TTS proteins as a result of either antisense suppression or sense cosuppression. These results identify TTS protein as a pistil component that positively contributes to pollen tube growth.
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Wu HM, Wang H, Cheung AY. A pollen tube growth stimulatory glycoprotein is deglycosylated by pollen tubes and displays a glycosylation gradient in the flower. Cell 1995; 82:395-403. [PMID: 7634329 DOI: 10.1016/0092-8674(95)90428-x] [Citation(s) in RCA: 143] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
In plant sexual reproduction, pollen tubes elongate from the stigma, through the stylar transmitting tissue, to the ovary of the pistil to deliver the male gametes for fertilization. TTS protein is a tobacco transmitting tissue glycoprotein shown to attract pollen tubes and promote their growth. Here, we show TTS proteins adhere to the pollen tube surface and tips, suggesting that they may serve as adhesive substrates for pollen tube growth. TTS proteins are also incorporated into pollen tube walls and are deglycosylated by pollen tubes, suggesting that they may provide nutrients to this process. Within the transmitting tissue, TTS proteins display a gradient of increasing glycosylation from the stigmatic end to the ovarian end of the style, coincident with the direction of pollen tube growth. These results together suggest that the TTS protein-bound sugar gradient may contribute to guiding pollen tubes from the stigma to the ovary.
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Wu HM, Zou J, May B, Gu Q, Cheung AY. A tobacco gene family for flower cell wall proteins with a proline-rich domain and a cysteine-rich domain. Proc Natl Acad Sci U S A 1993; 90:6829-33. [PMID: 8341705 PMCID: PMC47026 DOI: 10.1073/pnas.90.14.6829] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Flowering is known to be associated with the induction of many cell wall proteins. We report here five members of a tobacco gene family (CELP, Cys-rich extensin-like protein) whose mRNAs are found predominantly in flowers and encode extensin-like Pro-rich proteins. CELP mRNAs accumulate most abundantly in vascular and epidermal tissues of floral organs. In the pistil, CELP mRNAs also accumulate in a thin layer of cells between the transmitting tissue and the cortex of the style and in a surface layer of cells of the placenta in the ovary. This unique accumulation pattern of CELP mRNAs in the pistil suggests a possible role in pollination and fertilization processes. CELP genes encode a class of plant extracellular matrix proteins that have several distinct structural features: a Pro-rich extensin-like domain with Xaa-Pro3-7 motifs and Xaa-Pro doublets, a Cys-rich region, and a highly charged C terminus. The extensin-like domains in these proteins differ significantly in their length and these differences appear to be results of both long and short deletions within the coding regions of their genes. Furthermore, the number of charged amino acid residues in the C-terminal region varies among the CELPs. These structural differences may contribute to functional versatility in the CELPs. On the other hand, the Cys-rich domain is highly conserved among CELPs and the positions of the Cys residues are conserved, suggesting that this region may have a common functional role. The presence of a Pro-rich domain and a Cys-rich domain in these CELPs is reminiscent of a class of hydroxyproline-rich glycoproteins, solanaceous lectins, that are believed to be important in cell-cell recognition. The structure of these CELPs indicates that they may be multifunctional and that their genes may have arisen from recombinational events.
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Cheung AY, May B, Kawata EE, Gu Q, Wu HM. Characterization of cDNAs for stylar transmitting tissue-specific proline-rich proteins in tobacco. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 1993. [PMID: 8401601 DOI: 10.1111/j.1365-313x.1993.tb00018.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
The pistil of flowers is a specialized organ which contains the female gametophytes and provides the structures necessary for pollination and fertilization. Pollen deposited on the stigmatic surface of a compatible plant germinates a pollen tube which penetrates the stigmatic papillae and grows intercellularly through the style towards the ovules in the ovary. Pollen tube growth is largely restricted to the transmitting tissue in the style. Therefore the stylar transmitting tissue is extremely important for the migration of the pollen cell towards the ovary. We have isolated two related cDNAs, transmitting tissue-specific (TTS)-1 and TTS-2, derived from two proline-rich protein (PRP)-encoding mRNAs that accumulate specifically in the transmitting tissue of tobacco. The deduced PRP sequences share similarities with proline-rich cell wall glycoproteins found in a variety of plants. TTS-1 and TTS-2 mRNAs are induced in very young floral buds, accumulate most abundantly during the later stages of flower development when style elongation is the most rapid, and remain at relatively high levels at anthesis. These mRNAs become undetectable in maturing green fruits. In situ hybridization shows that TTS-1 and TTS-2 mRNA accumulation is restricted to the transmitting tissue of the style. The possible roles that these transmitting tissue-specific PRPs may play in maintaining the structural integrity of the style or in the function of this organ is discussed.
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Lolle SJ, Cheung AY. Promiscuous germination and growth of wildtype pollen from Arabidopsis and related species on the shoot of the Arabidopsis mutant, fiddlehead. Dev Biol 1993; 155:250-8. [PMID: 8416837 DOI: 10.1006/dbio.1993.1022] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
When pollen lands upon the stigmatic surface of a receptive flower, recognition events take place that permit germination, pollen tube growth, and tube penetration into the cell walls of the stigmatic papillae. Previously, we have described a mutant of Arabidopsis thaliana, named fiddlehead (fdh), where noncarpel organs of the shoot fuse late in ontogeny (Lolle et al., 1992). Here we demonstrate that wildtype Arabidopsis pollen grows on noncarpel organs of the fdh mutant. Pollen grains adhere, germinate, and emit pollen tubes when applied to vegetative and nonreproductive floral organs. Some of the emergent pollen tubes penetrate into the cell wall. Although pollen from a number of closely related species responds, tomato, tobacco, and snapdragon pollen does not. In addition, we show that organ fusion is not a prerequisite for pollen growth and that root epidermis does not express this activity. Based on these findings we propose that the fdh mutation identifies an important regulatory gene that controls the expression of an epidermis-specific developmental program normally expressed only during gynoecial ontogeny.
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Cheung AY, May B, Kawata EE, Gu Q, Wu HM. Characterization of cDNAs for stylar transmitting tissue-specific proline-rich proteins in tobacco. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 1993; 3:151-60. [PMID: 8401601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/16/2023]
Abstract
The pistil of flowers is a specialized organ which contains the female gametophytes and provides the structures necessary for pollination and fertilization. Pollen deposited on the stigmatic surface of a compatible plant germinates a pollen tube which penetrates the stigmatic papillae and grows intercellularly through the style towards the ovules in the ovary. Pollen tube growth is largely restricted to the transmitting tissue in the style. Therefore the stylar transmitting tissue is extremely important for the migration of the pollen cell towards the ovary. We have isolated two related cDNAs, transmitting tissue-specific (TTS)-1 and TTS-2, derived from two proline-rich protein (PRP)-encoding mRNAs that accumulate specifically in the transmitting tissue of tobacco. The deduced PRP sequences share similarities with proline-rich cell wall glycoproteins found in a variety of plants. TTS-1 and TTS-2 mRNAs are induced in very young floral buds, accumulate most abundantly during the later stages of flower development when style elongation is the most rapid, and remain at relatively high levels at anthesis. These mRNAs become undetectable in maturing green fruits. In situ hybridization shows that TTS-1 and TTS-2 mRNA accumulation is restricted to the transmitting tissue of the style. The possible roles that these transmitting tissue-specific PRPs may play in maintaining the structural integrity of the style or in the function of this organ is discussed.
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Lolle SJ, Cheung AY, Sussex IM. Fiddlehead: an Arabidopsis mutant constitutively expressing an organ fusion program that involves interactions between epidermal cells. Dev Biol 1992; 152:383-92. [PMID: 1644226 DOI: 10.1016/0012-1606(92)90145-7] [Citation(s) in RCA: 81] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
In most circumstances plant epidermal cells do not respond to surface contact with adjacent plant parts. We have identified and characterized a mutant of Arabidopsis thaliana, designated fiddlehead, where lateral appendages of the shoot fuse with one another. While fusion between floral organs is most frequent, leaf fusions also occur. Using scanning and transmission electron microscopy, we show that adhesion takes place between epidermal cells and does not involve cytoplasmic union. We also show that the frequency of organ fusion is dictated by organ proximity. In wildtype Arabidopsis, postgenital fusion takes place exclusively in the gynoecium, whereas in the fiddlehead mutant, this program becomes expressed constitutively. The existence of such a mutant demonstrates that postgenital fusion is a genetically distinct program superimposed upon other aspects of gynoecial development in Arabidopsis.
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Gu Q, Kawata EE, Morse MJ, Wu HM, Cheung AY. A flower-specific cDNA encoding a novel thionin in tobacco. MOLECULAR & GENERAL GENETICS : MGG 1992; 234:89-96. [PMID: 1495489 DOI: 10.1007/bf00272349] [Citation(s) in RCA: 84] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
We isolated a flower-specific cDNA, FST (flower-specific thionin), which encodes a novel thionin from tobacco. Thionins are basic and cysteine (Cys)-rich, low molecular weight proteins found in many plants. They are believed to play a role in plant defense against pathogens. The central domain of the FST protein shares homology with three gamma-thionins. Like other thionin precursors, the FST protein has an N-terminal domain characteristic of a signal peptide and an acidic C-terminal domain. FST mRNA accumulates specifically in developing flowers and its level drops as flowers mature. Transcripts are present in petals, stamens and pistil but are not detectable in sepals. In situ hybridization revealed that FST mRNA is most abundant in the epidermal cells along the adaxial surface of petals, and in the surface cell layers of the carpel and anther walls. If the FST protein indeed has a protective role in flowers, this pattern of spatial distribution of FST mRNA would appear to maximize this effect on the two internal reproductive whorls. A possible biological role for FST is discussed.
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Kawata EE, Cheung AY. Molecular analysis of an aurea photosynthetic mutant (Su/Su) in tobacco: LHCP depletion leads to pleiotropic mutant phenotypes. EMBO J 1990; 9:4197-203. [PMID: 2249672 PMCID: PMC552196 DOI: 10.1002/j.1460-2075.1990.tb07644.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Su is a nuclear encoded, semi-dominant aurea mutation in Nicotiana tabacum L. The homozygous plants (Su/Su) are pale yellow and non-photosynthetic while the heterozygous (Su/+) are photosynthetically competent and have a yellow-green phenotype which is distinct from that of green wild-type plants (+/+). We have examined the RNA and protein levels for a number of nuclear and plastid encoded chloroplast proteins under high and low light plant growth conditions. Under high light conditions, the light-harvesting chlorophyll a/b binding proteins (LHCP) were undetectable in the homozygous Su/Su plants, and the large subunit (LSu) and the small subunit (SSu) of ribulose bisphosphate carboxylase (Rubisco) and cytochrome b559 were severely deficient. However, only the nuclear encoded cab and plastid encoded psbE mRNA (encoding LHCP and cytochrome b559 respectively) were reduced significantly. In heterozygous Su/+ plants, the level of LHCP was reduced to 25% of that in wild-type plants while cab and psbE mRNA, LSu, SSu and cytochrome b559 remained at normal levels, suggesting that LCHP is more immediately affected by the Su mutant gene product than the rest of the photosynthetic proteins and mRNA examined. Under low light conditions, the levels of cab and psbE mRNA, LSu, SSu and cytochrome b559 in homozygous Su/Su plants were equivalent to those in wild-type plants except LHCP which remained undetectable. Similarly, the LHCP level in low light grown Su/+ plants still remained at 25% of wild-type level. These results indicate that the decrease in LHCP is independent of light conditions and has not resulted from photooxidation, whereas the depletion of other proteins and mRNA examined under high light growth conditions is a consequence of photooxidative damage to Su/Su plastids. Furthermore, transgenic Su/Su and Su/+ plants with a cauliflower mosaic virus 35S (CaMV 35S)-cab construct constitutively maintained high levels of cab mRNA but displayed the same pattern of diminished LHCP accumulation as their non-transformed counterparts when grown under both high and low light conditions. These results indicate that the Su mutation primarily causes depletion of LHCP. The depletion of LHCP leads to photooxidative damage which results in decreased cab mRNA levels and other pleiotropic lesions in Su/Su plants.
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Harbeck MC, Cheung AY, Suttie JW. Vitamin K-dependent carboxylase: partial purification of the enzyme by antibody affinity techniques. Thromb Res 1989; 56:317-23. [PMID: 2617472 DOI: 10.1016/0049-3848(89)90173-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The vitamin K-dependent carboxylase activity of bovine liver microsomes has been purified 500-fold by adsorption to an antiprothrombin column and elution with a dodeca peptide which competes with a prothrombin precursor enzyme recognition site. The purified enzyme is devoid of bound precursors, and has the same ratio of vitamin K epoxidase activity to carboxylase activity as the crude microsomal preparation.
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Gaspar LE, Cheung AY, Allen HH. Cervical carcinoma: treatment results and complications of extended-field irradiation. Radiology 1989; 172:271-4. [PMID: 2740513 DOI: 10.1148/radiology.172.1.2740513] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The authors studied treatment complications, recurrence patterns, and survival in 18 patients with histologically proved metastases to the paraaortic lymph nodes from invasive cervical carcinoma treated with extended-field irradiation. Complications following treatment developed in five of 10 patients who underwent transperitoneal nodal biopsy or dissection and in two of eight patients in whom an extraperitoneal approach was used (overall complication rate of 39%); however, only one had a gastrointestinal complication (small bowel obstruction after transperitoneal nodal biopsy and irradiation). Fourteen patients had persistent or recurrent disease within the abdominal or pelvic cavity; only one had distant metastases without recurrence in the abdomen or pelvis. Two of the 14 patients had a recurrence in the surgical scar following extraperitoneal nodal biopsy, possibly due to placement of the scar outside the radiation field. After a minimum follow-up of 48 months, only three of 18 patients (17%) were alive and well.
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Abstract
Between 1940 and 1985, 24 cases of primary carcinoma of the trachea were registered at the London Regional Cancer Centre. The most common presenting symptoms were hoarseness, haemoptysis and cough. Twenty patients had epidermoid carcinoma and four had adenoid cystic carcinoma. Because of different clinical behaviours, the two histologies were separately analyzed. Of the 20 patients with epidermoid carcinoma, 19 received radiotherapy as primary treatment and one patient did not receive radiotherapy because of advanced disease. Radiation doses ranged from 4000 to 6000 cGy and most patients had megavoltage irradiation. Treatment result was disappointing. Only one patient remained disease-free at 15-month follow-up and all other patients had persistent or recurrent tracheal tumour. Median survival for all 20 patients was 5 months (range 1 to 19 months). Of the four patients with adenoid cystic carcinoma, two had primary surgery and postoperative radiotherapy and two had primary radiotherapy. Two patients died of disease, at 5 months and 8 years from diagnosis. Two surviving patients had 15-month follow-up: one had persistent disease and the other was free from recurrence. In this study, radiotherapy within the range of doses given was found to be an ineffective primary treatment for tracheal carcinoma.
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Cheung AY, Chang KS. Effects of a sonographic technique for determining chest wall thickness in treatment planning for breast carcinoma. Int J Radiat Oncol Biol Phys 1988; 15:223-5. [PMID: 3292489 DOI: 10.1016/0360-3016(88)90371-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
This study investigated the use of a sonographic technique of determining chest wall thickness and the impact of dosimetric correction for lung inhomogeneity on treatment planning for breast irradiation after lumpectomy or partial mastectomy. The thickness of the chest wall in three planes of the radiation field was obtained using a B-mode ultrasound scanner and the location of the pleura-lung interface was marked on the contour of the chest wall in each plane. Treatment plans for 88 patients were developed with and without correction for the lung tissue included in the radiation volume. All patients were irradiated with an opposing pair of tangential fields to the breast with a 6 MV X ray beam using an isocentric set-up. Within the treatment volume, dose variation of +/- 5% of the prescribed tumor dose was aimed for in the treatment planning. With correction for lung tissue, the proportion of treatments given with a wedge filter was found to be on the average 20% less than it would be without lung correction. The described sonographic technique is simple to perform and reproducible. It improves the accuracy of dosimetry in treatment planning for breast carcinoma.
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Abstract
Following single-agent or combination chemotherapy, 9 patients with epithelial carcinoma of the ovary had elective second-look laparotomy. Macroscopic intraperitoneal disease was resected in 4 patients. Therefore, after the laparotomy, all 9 patients had only biopsy-proven, microscopic residual disease, and they received whole abdominopelvic irradiation. Hematological tolerance was satisfactory, with only 2 patients developing asymptomatic thrombocytopenia. Mild gastrointestinal reactions, while frequent during radiotherapy, did not interrupt treatment in any patient. After follow-up from 12 to 34 months (median 16 months) [corrected], 2 patients died of cancer, 2 were alive with cancer, 3 were alive without clinical recurrence, and 2 were alive without biopsy-proven recurrence. Bowel complication occurred in 4 patients: 2 developed intestinal obstruction due to recurrent tumor, 1 developed subacute bowel obstruction which spontaneously resolved, and 1 patient required bowel resection because of a radiation complication. This study indicated that after single- or multiple-drug chemotherapy, most patients could complete the course of whole abdominopelvic irradiation. Gastrointestinal complications could be secondary to radiation damage or to recurrent tumor. While whole abdominopelvic irradiation was not an effective second-line treatment, some long-term survivors could still be expected.
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Cheung AY, Watson L, Söll D. Two control systems modulate the level of glutaminyl-tRNA synthetase in Escherichia coli. J Bacteriol 1985; 161:212-8. [PMID: 2578447 PMCID: PMC214858 DOI: 10.1128/jb.161.1.212-218.1985] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
We studied the regulation of in vivo expression of Escherichia coli glutaminyl-tRNA synthetase at the transcriptional and translational level by analysis of glnS mRNA and glutaminyl-tRNA synthetase levels under a variety of growth conditions. In addition, strains carrying fusions of the beta-galactosidase structural gene and the glnS promoter were constructed and subsequently used for glnS regulatory studies. The level of glutaminyl-tRNA synthetase increases with the increasing growth rate, with a concomitant though much larger increase in glnS mRNA levels. Thus, transcriptional control appears to mediate metabolic regulation. It is known that glnR5, a regulatory mutation unlinked to glnS, causes overproduction of glutaminyl-tRNA synthetase. Here we showed that the glnR5 product enhances transcription of glnS 10- to 15-fold. The glnR5 mutation does not affect metabolic control. Thus, glnS appears to be regulated by two different control systems affecting transcription. Furthermore, our results suggest post-transcriptional regulation of glutaminyl-tRNA synthetase.
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Cheung AY, Neyzari A. Deep local hyperthermia for cancer therapy: external electromagnetic and ultrasound techniques. Cancer Res 1984; 44:4736s-4744s. [PMID: 6467228] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
External heating techniques for delivery of localized hyperthermia in patients are reviewed. This paper covers microwaves, radiofrequency, and ultrasound methods. Fundamental principles governing tissue absorption, guidelines for applicator selection and design, and restrictions of each heating approach are discussed. Innovative techniques utilizing multiple applicators to achieve better heating uniformity are also presented. The advantages and disadvantages of electromagnetic versus ultrasound heating techniques are compared as a conclusion to this review.
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Cheung AY, Söll D. In vivo and in vitro transcription of the Escherichia coli glutaminyl-tRNA synthetase gene. J Biol Chem 1984; 259:9953-8. [PMID: 6086662] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
We have characterized the in vivo and in vitro transcription products of the Escherichia coli glnS gene which codes for the enzyme glutaminyl-tRNA synthetase. The in vivo glnS transcript is about 1.9 kilobases long. Sequence analysis of the 5'- and 3'-ends of glnS mRNA showed that transcription initiates approximately 30 bases upstream from the translation initiation codon AUG and terminates approximately 230 bases downstream from the termination codon UAA. Characterization of the in vitro transcripts of glnS revealed similar transcription initiation and termination sites as were found in the glnS mRNA produced in vivo. These results indicate that the Pribnow box structure upstream and the dyad symmetry terminator structure downstream of the glnS structural region are regulatory signals used for glnS expression. In vitro transcription of glnS is not autogenously regulated by glutaminyl-tRNA synthetase and glutamine; it is also not affected by the presence of tRNA.
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Cheung AY, Söll D. In vivo and in vitro transcription of the Escherichia coli glutaminyl-tRNA synthetase gene. J Biol Chem 1984. [DOI: 10.1016/s0021-9258(17)42791-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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Fisher B, Cheung AY. Delayed effect of radiation therapy with or without chemotherapy on ovarian function in women with Hodgkin's disease. ACTA RADIOLOGICA. ONCOLOGY 1984; 23:43-8. [PMID: 6328887 DOI: 10.3109/02841868409135984] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
In this retrospective investigation of 51 female patients with Hodgkin's disease, the age of the patient at the time of primary treatment and the extent of radiation therapy were the two most important factors determining post-therapy ovarian function. Favourable indicators of ovarian preservation included young age, especially premenarchal , at the time of primary therapy, and irradiation confined to above the pelvic brim, whereas, age over 40 and irradiation below the pelvic brim predicted high probability of ovarian failure. Overall, 55 per cent of female patients under the age of 50 treated with chemotherapy alone or with radiation therapy above the pelvic brim retained normal ovarian function. The stage of disease at presentation and the post-therapy status of disease had no apparent effect on subsequent menstrual function.
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Samaras GM, Rosenbloom S, Cheung AY. Correction of microwave-induced thermistor sensor errors. Med Phys 1983; 10:326-32. [PMID: 6877180 DOI: 10.1118/1.595261] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Accurate and reliable thermometry is essential in the development of microwave-induced hyperthermal cancer therapy. While temperature measurements in strong electromagnetic fields usually require special sensors, this does not hold true for interstitial radiator/sensor systems. Miniature thermistors (with metallic leads) bonded to invasive microwave applicators exhibit a sensor error linearly related to the radiator's transmitted power. This relationship permits thermistor sensor error correction and temperature measurements to within +/- 0.1 degrees C or better. The instrumental methods and empirical validation are presented.
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Scott RM, Cheung AY, Samaras GM. Clinical local heating by microwaves. NATIONAL CANCER INSTITUTE MONOGRAPH 1982; 61:351-5. [PMID: 6757752] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The advantages and limitations of microwave heating in clinical thermotherapy are reviewed on the basis of the clinical experiences of various investigators who used microwave-induced hyperthermia. Also discussed are the clinical engineering system requirements necessary for conducting controlled clinical trials, as well as appropriate thermal treatment planning. Lastly, we present the future prospects for complex antennas and treatment control systems.
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Cheung AY. Microwave and radiofrequency techniques for clinical hyperthermia. THE BRITISH JOURNAL OF CANCER. SUPPLEMENT 1982; 5:16-24. [PMID: 6950753 PMCID: PMC2149329] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Biological and practical constraints on the use of clinical hyperthermia for the management of cancer are discussed. Commonly used electromagnetic techniques for producing clinical hyperthermia are reviewed and compared. Innovative engineering designs leading to the realization of an integrated, safe and reliable clinical hyperthermia system are also presented.
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Robinson JE, McCulloch D, Harrison GH, Cheung AY. Thin-layer liquid crystal thermometry of cells in vitro during hyperthermal microwave irradiation. Bioelectromagnetics 1982; 3:237-45. [PMID: 6751334 DOI: 10.1002/bem.2250030208] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
A nonperturbing technique of thin-layer liquid crystal thermometry was developed to quantitate heating of Chinese hamster ovary cells and the bacterium Serratia marcescens when exposed to 2450-MHz microwave fields at 0.2-0.5 W/cm2. Cells suspended in culture medium were injected into 5-cm glass microcapillary tubes coated on the inside with a thin layer of liquid crystal. The tubes were sealed and placed parallel to the electric field in a watertight waveguide exposure chamber where they were heated by circulating temperature-controlled water. Even at high circulation rates, liquid crystal color changes indicated local microwave capillary tube heating of 0.1-0.25 degrees C. Precision of measurement was 0.02 degrees C. Observations during microwave heating were significantly different from observations without microwaves at the 1% level, and heating increased as circulating water flow was reduced from 300 ml/s to 100 ml/s. The results of a cell survival assay following hyperthermal treatment were in good agreement with expectations based on the observations of microwave heating using liquid crystals.
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