bluuebunny/crossref_metadata_2025_split huggingface dataset:
Relative calcium‐binding strengths of amino acids determined using the kinetic method
Authors: Ho Yen‐Peng , Yang Ming‐Wei , Chen Li‐Ting , Yang Yu‐Chuan 
Published: February 2007

AbstractWe have measured the relative calcium‐binding energies of amino acids using tandem mass spectrometry of Ca2+‐bound trimeric amino acids. Although calcium‐bound dimeric amino acid complexes coordinated too strongly to allow observation of the two competing dissociation products (calcium‐bound monomeric ions) required for analysis of their metal binding affinities using the conventional kinetic method, the Ca2+‐bound trimeric cluster ions dissociated readily to form dimeric cluster ions through simple ligand losses. The calcium‐binding energies were obtained by comparing the ratio of the [Ca2+(A1)2  H+]+ and [Ca2+ (A1)(A2)  H+]+ ions that dissociated from the [Ca2+ (A1)2(A2)  H+]+ ion and the ratio of the [Ca2+(A2)2  H+]+ and [Ca2+(A1) (A2)  H+]+ ions that dissociated from the [Ca2+(A1)(A2)2  H+]+ ion, where A1 and A2 represent two amino acids. The energies deduced from this analysis represent the relative average binding energies of complexes having the form [Ca2+(A1)2  H+]+. The relative Ca2+‐binding strengths of the α‐amino acid complexes follow the order Cys < Ser < Thr < Ile < Leu < Val < Gly < Ala < Pro < Phe < Met < Tyr < Asn < His < Gln < Trp < Lys < Arg. To our knowledge, this report provides the first example of using kinetic methods to determine the relative binding strengths of divalent metal–amino acid complexes. Copyright © 2007 John Wiley & Sons, Ltd.
Human Melanoma Cells: Relationship Between Their Radiosensitivity and the Repair of Potentially Lethal Damage
Authors: Utsumi H. , Elkind M. M. 
Published: February 2007

AbstractFrom clinical experience, malignant melanomas are generally considered to be radioresistant. To explain this impression, the hypothesis had been advanced that the melanoma cells in a tumor are inherently resistant and that they are so because they are particularly effective in repairing potentially lethal damage. We have examined this idea with several lines of melanoma cells, and we have compared the responses of these cells to those of normal and ataxia telangiectasia fibroblasts (both SV40 transformed). The single‐dose responses of the melanoma cells were found to cover a large range. The most sensitive had a response similar to that of normal fibroblasts, but the most resistant required a dose for 10% survival to be 2–3 times larger. Correlated with this range in response, we found the sensitive melanoma cells to be deficient in both the fast and slow repair of potentially lethal damage compared to resistant melanoma cells. Sensitive and resistant melanoma cells survived ultraviolet light exposure equally well, however. We conclude that the repair of potentially lethal damage is important to the X‐ray response of melanoma cells, but that the degree of such repair correlates with the inherent sensitivity of such cells. Consistent with many other types of observations, we also note that the mechanism of lethality by ionizing radiation is fundamentally different from that of ultraviolet light. © 1993 Wiley‐Liss, Inc.
Effects of Recombinant Interleukin‐3 and Recombinant Interleukin‐6 on Radiation Survival of Normal Human Bone Marrow Progenitor Cells
Authors: Waddick Kevin G. , Uckun Fatih M. 
Published: February 2007

AbstractThe effects of recombinant interleukin‐6 (rIL‐6) and rIL‐3 on the radiation responses of myeloid [colony forming unit‐granulocyte‐macrophage (CFU‐GM)] and erythroid [burst forming unit‐erythroid (BFU‐E)] human pediatric bone marrow progenitor cells were analyzed. Cytokine exposure times of 30 min, 1 hr, 2 hr, 4 hr, 16 hr, and 24 hr were used prior to irradiation. The most notable observations were based on short exposure data, which provided unprecedented evidence that rIL‐6 increases the radiation damage repair capacity of both CFU‐GM and BFU‐E without affecting their radiation sensitivity, whereas rIL‐3 modulated the radiation responses of CFU‐GM only. The cytokine‐induced increase in radiation survival of CFU‐GM or BFU‐E at doses ≤200 cGy appeared to be primarily due to an increase in the ability of these hematopoietic progenitor cell populations to repair sublethal radiation damage.
Inhibition of Polyamine Synthesis Suppresses Growth and γ‐Ray‐Induced Sublethal and Potentially Lethal Damage Recovery in Human Tumor Cells in Culture
Authors: Stea Baldassarre , Buatti John M. , Stringer David E. , Gerner Eugene W. 
Published: February 2007

AbstractPolyamines are ubiquitous polycations that interact with negatively charged macromolecules, including DNA. Since DNA is a target for radiation damage, we tested the hypothesis that radiation survival responses are polyamine‐dependent in cells derived from human tumors arising at different sites (lung [A549], cervix [HeLa], and brain [D54 and U251]). Untreated cultures displayed different growth rates (HeLa ≈ A549 > D54 > U251). Treatment with the specific ornithine decarboxylase inhibitor α‐difluoro‐methylornithine (DFMO) for 2 days or more suppressed putrescine and spermidine contents in all four cell lines. DFMO inhibited growth of each line, but to varying degrees (U251 > HeLa ≈ A549 > D54). Polyamine depletion generally suppressed γ‐ray‐induced sublethal and potentially lethal damage recovery. The degree of suppression of these recovery processes varied among cell lines (D54 > A549 ≈ HeLa > U251), which correlated inversely with the ability of DFMO to suppress cell growth. These data suggest that agents such as DFMO, which suppress polyamine contents, may be useful adjuvants to radiation therapy by inhibiting either radiation recovery processes or cell proliferation, or both, during fractionated radiotherapy schedules. © 1993 Wiley‐Liss, Inc.
Prognostic Value of Cellular DNA Content and S‐Phase Fraction in Head and Neck Squamous Cell Carcinomas in Relation to Different Treatment Modalities
Authors: Fietkau Rainer , Iro Heiner , Altendorf‐Hofmann Annelore , Sauer Rolf 
Published: February 2007

AbstractDNA‐ploidy and the percentage of S‐phase cells were measured by DNA flow cytometry in 171 primary squamous cell carcinomas of the head and neck. Of the analyzed tumors, 102 (60%) were aneuploid and 69 (40%) were diploid. Minimum follow‐up was 6 months (median: 37 months). For the whole population no difference of the 5‐year survival rate was found comparing diploid (18%) and aneuploid tumors (26%). Following sequential radiochemotherapy, aneuploid tumors revealed a better 5‐year survival (54%) than diploid tumors (7%;P< 0.01). Accordingly, the locoregional control rate was higher for aneuploid tumors (57% vs. 28%; n.s.). By contrast, following surgery and radiotherapy or concurrent radiochemotherapy, diploid and aneuploid tumors had nearly the same survival rates. The analysis of recurrence demonstrated a lower rate of locoregional failures of diploid tumors (surgery + radiotherapy: 32% vs. 44%), but this was leveled out by a higher incidence of distant metastases of diploid carcinomas (surgery + radiotherapy: 36% vs. 17%). Relating to the fraction of S‐phase cells, slowly proliferating tumors (S‐phase < median; 28%) had a better 5‐year survival rate than fast proliferating tumors (20%;P< 0.05). The same was true for different treatment modalities surgery + radiotherapy; concurrent or sequential radiochemotherapy) and for the investigated stage III and IV tumors according to UICC 1987. The analysis of recurrence revealed that the better survival of slowly proliferating tumors was explained by the higher locoregional control rate (60%) compared to fast proliferating tumors (45%;P< 0.05). Stepwise multivariate analysis revealed treatment modality (P= 0.107), S‐phase fraction (P= 0.026), and UICC stage (P= 0.044) as independent prognostic factors for locoregional recurrences and S‐phase fraction (P= 0.0143) for 3‐year overall survival. These data indicate that flow cytometrically evaluated DNA‐ploidy and S‐phase fraction have a relevant prognostic power for predicting the clinical outcome of squamous head and neck cancer. © 1993 Wiley‐Liss, Inc.
Radiation sensitization of chinese hamster V79 cells by paclitaxel
Authors: Cook John A. , Degraff William , Teague Diane , Liebmann James K. 
Published: February 2007

AbstractBecause paclitaxel has been reported to disrupt microtubules and block cells in G2/M of the cell cycle, the radiation response of Chinese hamster V79 cells exposed to various paclitaxel concentrations and durations of exposure was evaluated. Parallel to clonogenic cell survival studies, paclitaxel‐mediated perturbations on the cell cycle were also assessed by flow cytometry. While short‐term incubation (0–6 hr) with 0.1, 1, or 10 μM paclitaxel caused a gradual accumulation of cells into G2/M, no radiosensitization was observed. Incubation with 0.05—1 μM paclitaxel for 12 hr followed by X‐ray treatment resulted in radiosensitization (enhancement ratio at the 10% survival level = 1.7). Paclitaxel concentrations above 1 μM had similar effects on the cell cycle at lower concentrations, yet radiosensitization decreased such that at 10 μM no radiosensitization was observed. Likewise, no radiosensitization was observed for cells incubated for 24 hr with 0.1, 1 or 10 μM paclitaxel and irradiated. Cell cycle analysis indicated that cells receiving less than 0.25 μM paclitaxel for 12 hr were only transiently blocked in mitosis and then went on to complete mitosis; cells receiving greater than 0.25 μM paclitaxel for 12 hr or more became polyploid, i.e., cells moved into a semisynchronous tetraploid G1 state. (Cells irradiated at 24 hr had progressed to a tetraploid G2 state.) Taken as a whole, these results indicate that paclitaxel‐mediated radiosensitization and cell cycle perturbation are both time and concentration dependent. © 1993 Wiley‐Liss, IncThis article is a US government work and, as such, is in the public domain in the United States of America.
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Preliminary results of a prospective randomized controlled clinical trial with hydroxyurea and cisplatinum as radiosensitizers in advanced carcinoma of the cervix
Authors: Smit Ben , van der Merwe Andre 
Published: February 2007

AbstractSixty‐three patients with cervical carcinoma were randomized prospectively to receive radiation therapy alone, or hydroxyurea (HU) and cisplatinum as radiosensitizers. All patients were treated by a four field box technique, 2.5 Gy daily, 4 days per week, to a total dose of 50 Gy (TDF 90). A central boost by high dose rate intracavitary therapy (HDR‐ICT), 4.2 Gy daily × 4 was given on the same days (with a 6 hr gap between fractions) during the last 4 days of external beam therapy. This reduced the overall treatment time from 6 to 5 weeks. The Indwelling Intrauterine Tube technique was used. The summated dose at point A is 66.8 Gy (TDF 130). Twenty patients (group A) received radiation therapy (RT) only; 21 (group B) received cisplatinum 15 mg/m2 on alternate days, plus RT; 22 patients (Group C) received HU 80 mg kg/body weight on alternate days, plus RT. The median time of follow‐up is 14 months for group A and 19 months for the other two groups. The survival probability for patients with at least 20 months follow‐up (Kaplan‐Meier method) is 0.61, 0.88, and 0.84; disease‐free survival is 0.42, 0.63 and 0.62 for groups A, B, and C, respectively, which are not statistically significantly different. Early complications: Moderate to severe cystitis was seen in 15,4.76, and 9.09%; proctitis in 5,0, and 4.5%, and diarrhoea in 5, 14.29, and 13.64% for groups A, B, and C; for a total of 25, 19.05, and 27.28%, respectively. Late moderate to severe complications: Cystitis occurred in 0,9.5, and 4.55%, and proctitis in 10,4.76, and 9.09% in groups A, B, and C, respectively. One patient in group B (4.76%) and two patients in group C (9.09%) developed chronic diarrhoea giving a total late complication rate of 10, 19.04, and 22.7%, respectively. In addition, vaginal stenosis occurred in 15, 23.81, and 9.09% in groups A, B, and C, respectively. No rectovaginal fistulae developed in any of the three groups. All except 1 of the 63 patients completed their treatment. Three patients out of group A, 2 out of group B, and 1 out of group C were lost to follow‐up. One out of the 63 patients, 1.56% (group C) needed a colostomy for a grade III late proctitis. Drug related toxicity was not severe and proved that the regimens could be tolerated. Treatment had to be interrupted in group A, because of treatment related morbidity, for 2 days in one patient, 2 weeks in a second, and terminated in a third after 45 Gy teletherapy due to unrelated problems. There were no treatment interruptions in group B. In group C, 2 patients were rested for 7 days each as a result of a low white cell count (WCC). The incidence of metastatic disease was the lowest in group B; the complication rate the highest in group C. The results indicate that cooperative controlled studies based on these results should be considered. © 1993 Wiley‐Liss, Inc.
Expression of the transcriptional activator tax protein of human T‐cell leukemia virus type I increases the radiosensitivity of a mouse fibroblast cell line to ionizing radiation
Authors: Santucci Maria Alessandra , Holland Christie A. , Anklesaria Pervin , Das Indra , Fitzgerald T. J. , McKenna Michael G. , Sakakeeny Mary Ann , Greenberger Joel S. 
Published: February 2007

AbstractHuman T‐cell leukemia virus type I (HTLV‐1) is the etiologic agent for adult T‐cell leukemia (ATL). Among the X region products of HTLV‐1, the p42 kDa protein Tax was identified, as responsible for cell immortalization and transformation. However, the observations that only a low percentage of individuals infected with HTLV‐1 eventually progress to leukemia and that leukemic transformation of HTLV‐1‐infected cells is associated with aberrant karyotype suggest that additional genetic events are required for HTLV‐1‐induced malignant transformation. Results of our study demonstrate that expression of the Tax protein of HTLV‐1 increased the radiosensitivity of a mouse fibroblast cell line. These data are consistent with a previous report indicating a negative regulatory control by Tax on DNA repair. Unrepaired DNA damage and karyotypic instability could represent a common factor in both the initiation and progression of HTLV‐1‐related diseases. © 1993 Wiley‐Liss, Inc.
Frequencies of micronuclei in human lymphocytes: Comparison between healthy donors and cancer patients and their in vitro response to ionizing radiation
Authors: Lee Tung‐Kwang , Wiley Albert L. , Means Julie A. , Esinhart James D. , Blackburn Lisa D. 
Published: February 2007

AbstractWe obtained peripheral lymphocytes from both healthy donors (n = 7) and cancer patients (n = 14) for the cytokinesis‐blocked micronucleus (MN) assay. Lymphocytes were irradiated with 137Cs to 2 Gy. Cytochalasin B (6 μg/ml) was added to the incubation at 44 hr and the cells were harvested at 72 hr. We found that compared to healthy donors, lymphocytes of cancer patients revealed no significant difference in the MN baseline level (P = 0.86). Apparently DNA damage manifested as MN in the lymphocytes of cancer patients is not more severe than that of healthy donors. In addition, 2 Gy in vitro irradiation of lymphocytes caused no difference in the MN formation between cancer patients and healthy donors (P = 0.9). Radiation induced cell cycle delay as evaluated by the number of mononucleate, binucleate, and cells with >2 nuclei and by the mitotic indices showed similar results in both populations. However, the difference for MN frequency in lymphocytes before and after 2 Gy in vitro irradiation was highly significant for both cancer patients and healthy donors (P = 0.0001). These studies in general indicate that the MN frequency in cytochalasin B‐blocked human lymphocytes has the potential of serving as a quantitative biological dosimeter for the screening of radiation exposure to either healthy individuals or cancer patients. © 1993 Wiley‐Liss, Inc.
Morphometric studies in early stage breast ancer with an intraductal component using computerized image analysis
Authors: Mayr Nina A. , Robinson Robert A. , Wen B.‐Chen , Ross Cynthia S. , Hass A. Curtis , Stoffel Thomas J. , Fisher David J. , Vanmetre John E. , Hussey David H. 
Published: February 2007

AbstractThe hypothesis that hypoxia may be present in the intraductal component associated with infiltrating breast cancer was tested by studying the morphology of the intraductal component with respect to expansion of the tumor‐filled breast ducts and intraductal necrosis. Of 52 consecutive patients with T1–2N0–1M0 infiltrating ductal breast carcinoma, 10 had an extensive intraductal component (EIC), 27 had a limited intraductal component (LIC), and 15 had no intraductal component. The necrosis‐containing comedo‐ and cribriform‐predominant types of intraductal carcinoma were common (50%) in the EIC group, but infrequent (19%) in the LIC group. The frequency of intraductal necrosis increased with duct diameter. Seventy‐five percent of ducts with a radius exceeding the oxygen diffusion distance (>180 μm) contained necrosis compared with 33% of ducts below that size. The average duct diameter was significantly larger (404 μm; P = 0.0056) and intraductal necrosis was more common (61%) in the EIC group than in the LIC group (263 μm; 33%). All patients with local recurrence in the EIC group (20%) had the comedo‐predominant pattern, with a high percentage (79%) of necrotic ducts. The increasing frequency of intraductal necrosis with increasing duct size, particularly with radii of more than 180 μm, suggests that tumor cell hypoxia is present in the intraductal component. The larger duct size and higher frequency of necrosis in the EIC group suggest that hypoxia is more common in EIC than in LIC. © 1993 Wiley‐Liss, Inc.
Calculation of complication probability of pion treatment at paul scherrer institute using dose‐volume histograms
Authors: Nakagawa Keiichi , Akanuma Atsuo , Aoki Yukimasa , Karasawa Katsuyuki , Sasaki Yasuhito , Blattmann Hans , Coray Adorf 
Published: February 2007

AbstractIn conformation radiotherapy a target is irradiated uniformly, whereas surrounding organs receive non‐uniform radiation. Clinical data concerning complications with conventional radiation are not applicable there without appropriate compensation. A solution was proposed by Lyman [Int J Radiat Oncol Biol Phys 13:103–109, 1987 and 17:433–436, 1989; Radiat Res Suppl 8:13–19, 1985] using dose‐volume histograms. It reduces a given histogram to a single step which corresponds to the equivalent complication probability. It converts non‐uniform radiation into a unique dose to the whole organ which has the equivalent complication probability. This method was applied to actual patients treated by pion conformation technique at Paul Scherrer Institute (PSI). Of 90 pelvic tumors, 16 developed grade III‐TV bladder injury and 7 developed grade III‐IV rectal injury. The 90 cases were divided into roughly equal groups according to the equivalent doses to the entire bladder and rectum. Observed complication rates and the equivalent doses to the full organs in these groups could be represented by a sigmoid dose‐effect relation. When the relative biological effectiveness (RBE) is assumed to be 2.1 for bladder injury, the observed complication rates of the bladder fit best to the theoretical curve. When the RBE value is 2.3, the rates of rectal injury fit best. These values are close to the conversion factor of 2.0 used in clinical practice. This agreement suggests the feasibility of the method. © 1993 Wiley‐Liss, Inc.
Short‐term results of computerized tomographic‐based transperineal iodine‐125 prostate implantation
Authors: Wallner Kent , Roy Jitendra , Zelefsky Michael , Harrington Patrick , Fuks Zvi , Harrison Louis 
Published: February 2007

AbstractThere has recently been a resurgence of interest in iodine‐125 (I‐125) prostate implantation for early stage carcinoma due to the introduction of transrectal ultrasonography (TRUS) or computerized‐tomographic (CT)‐based transperineal techniques. The present study details initial tumor response and morbidity of CT‐based transperineal prostate implantation. Forty‐two patients with clinical stage T1 or T2 prostatic carcinoma had CT‐planned transperineal I‐125 implantation of the prostate and have been followed for 6–47 months (median: 19 months). Thirty‐eight patients had an elevated PSA before implantation (>4.0 ng/ml). A total of 35–73 mCi I‐125 was implanted (median: 48 mCi). At 1 year after implantation, 84% of 29 palpable tumors were no longer palpable. Of 38 patients with an elevated prostate specific antigen (PSA) prior to implantation, 98% returned to normal within 12 months of treatment. In 74% of patients, the PSA value fell to below 1.0 ng/ml within 12 months of implantation. Of 25 patients who were sexually potent prior to implantation, 80% remained potent at 3 years. Four patients developed radiation‐induced rectal ulcerations 9–19 months following implantation. Of those four patients, one has healed spontaneously, two are improving, and one was diagnosed only 1 month prior to this report. Initial tumor response to I‐125 implantation is comparable to that achieved with external beam irradiation, with acceptable morbidity and high preservation of sexual potency. With adjustments in technique, morbidity is expected to be lower in the future. © 1993 Wiley‐Liss, Inc.
Radiation response of NIH/3T3 mouse fibroblasts overexpressing human poly(adenosine diphosphate ribose) polymerase
Authors: Jorgensen Timothy J. , Notario Vicente , Thraves Peter J. , Dritschilo Anatoly 
Published: February 2007

AbstractPoly(adenosine diphosphate ribose) [poly(ADP‐ribose)] polymerase is a mammalian enzyme which synthesizes long chains of ADP‐ribose attached to various nuclear proteins in response to DNA strand breaks. A role for this enzyme in cellular radioresistance has been postulated due to the radiosensitizing effect of chemical inhibitors of the enzyme on some cell lines. Inhibitor studies, however, lack specificity and direct evidence for involvement of the enzyme in radioresistance is still needed. In experiments described here, intracellular levels of the enzyme were modulated using vectors to express sense and antisense human cDNA transcripts of poly(ADP‐ribose) polymerase in stably transfected NIH/3T3 mouse fibroblasts. Although antisense constructs failed to lower enzyme levels, sense transcripts increased enzyme levels. None of the transfectants, however, showed any difference in either radiation sensitivity or DNA strand break repair rates. These results suggest that simple elevation of poly(ADP‐ribose) polymerase does not affect the intrinsic cellular radioresistance of these cells. © 1993 Wiley‐Liss, Inc.