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Presurgical cytoreduction of oral cancer using intra-arterial cisplatin and limited concomitant radiation therapy (Neo-RADPLAT).

OBJECTIVE: To determine the effectiveness of a cytoreduction strategy for oral cancer using a novel trimodal therapy. METHODS: Prospective analysis of 25 patients treated between October 1995 and June 2000 with a protocol named neo-RADPLAT consisting of 4 weekly intra-arterial infusions of cisplatin (150 mg/m2) and intravenous infusions of sodium thiosulfate (9 g/m2), and concurrent radiation therapy (2 daily doses of 50 Gy) followed by tumor nidusectomy (a conventional surgery) at 8 weeks. Five patients had T2 lesions and 20 patients had T3 lesions; the clinical neck cancer stages were N0 in 12 patients, N1 in 9, and N2 in 4 (2 N2a, 1 N2b, and 1 Nc); and there were 17 tumors of the oral cavity (11 of the oral tongue, 5 of the retromolar trigone, and 1 of the floor of mouth) and 8 of the oropharynx (4 of the tonsillar fossa, 3 of the base of tongue, and 1 of the soft palate). RESULTS: Twenty patients (80%) had a complete response to chemoradiation in the primary site and 11 (79%) had a complete response in the neck. Among the 19 patients who had a tumor nidusectomy after chemoradiation, 5 had residual cancer and required a conventional resection. With regard to major toxicity, there were 6 cases of grade 3 and 1 case of grade 4 hematologic effects, 1 case of grade 3 neurologic effect, 1 case of grade 3 gastrointestinal effect, 1 case of grade 5 cardiac effect, as well as 16 cases of grade 3 mucositis. With a median follow-up of 56 months (range, 28-84 months), the 5-year estimates for overall survival, disease-specific survival, and locoregional control were 54%, 64%, and 74%, respectively. Fourteen patients remain without disease, 6 have died of the disease, and 5 have died of other causes. CONCLUSIONS: Preoperative intra-arterial chemoradiation cytoreduction followed by limited surgery is effective for controlling oral cancer. This tissue-sparing and reduced-radiation strategy may also preserve oral function.

Adolescent↗

A novel organ preservation protocol for advanced carcinoma of the larynx and pharynx.

OBJECTIVE: To pilot a targeted chemoradiation protocol for patients with advanced carcinoma of the larynx and pharynx that would circumvent upper aerodigestive tract dysfunction related to major oncologic surgery. DESIGN: Weekly intra-arterial infusions of supradose cisplatin (150 mg/m2 per week x 4) rapidly delivered to the tumor bulk, simultaneous intravenous sodium thiosulfate for systemic drug neutralization, and conventional external-beam irradiation (1.80-2.00 Gy per fraction x 35) were used. Between February 1991 and April 1994, 42 patients were treated who would otherwise have required a major resection of the tongue base, pharyngeal wall, or larynx. MAIN OUTCOME MEASURES: Tumor response, toxic effects, disease control above the clavicle, preservation of the larynx, maintenance of oral nutrition, and overall and disease-related 2-year survival. RESULTS: Three complications were related to the weekly transfemoral superselective intra-arterial procedures performed 160 times. Grade 3 to 4 chemotoxic effects were infrequent, occurring in 9 (5.5%) of 160 cycles, and only 1 patient required a radiotherapy break because of severe mucositis. A complete response in the primary site was obtained in 36 (86%) of 42 patients, 2 of whom had residual disease in the neck. Median follow-up was 13 months (range, 3-46 months). To date, there have been 5 recurrences: 2 regional and 3 distant. The 2-year overall and disease-related survival was 64% and 76%, respectively. The rate of disease control above the clavicle at 2 years was 86%. CONCLUSIONS: We believe this chemoradiation protocol represents an effective management scheme for patients with advanced head and neck cancer while minimizing dysfunction and possibly improving survival.

Adolescent↗

Hydrogen sulfide poisoning: clarification of some controversial issues.

BACKGROUND: Hydrogen sulfide is a toxic gas about which much has been written. We discuss here several issues we believe would benefit from further clarification. CONCLUSIONS: We conclude that: 1) Certain neurotoxic effects of exposure are probably due to a direct toxic effect on the brain, while others are almost certainly a result of hypoxia secondary to H2S-induced respiratory insufficiency; 2) pulmonary edema is a common consequence of poisoning and there is suggestive evidence of hyperactive airway responses in some individuals following brief H2S-induced unconsciousness (knockdown); 3) criteria for acceptable community levels are very different than those governing occupational standards; 4) urinary thiosulfate determinations can be useful for monitoring occupational exposure; and 5) determination of sulfide ion concentrations in blood or major organs can be useful in corroborating a diagnosis of fatal H2S toxicity, but there are many pitfalls in collecting, storing, and analyzing tissue and fluid samples.

Air Pollutants↗

Accidental intramuscular injection of mechlorethamine.

A 55-year-old man with chronic, active diffuse psoriasis was accidentally given 30 mg of mechlorethmine deep into the buttock muscles. About 5 hours after the intramuscular (IM) mechlorethamine injection, 1/6 M sodium thiosulfate was infused around the intramuscular site. Although systemic responses to the mechlorethamine developed, the expected muscular and adjacent skin destruction did not occur. Instead, IM mechlorethamine induced only minimal local tenderness.

Antidotes↗

Cisplatin administered by the intracavitary route as treatment for malignant mesothelioma.

Twenty-one patients with malignant mesothelioma were treated with an experimental intracavitary chemotherapy regimen of weekly intraperitoneal or intrapleural cisplatin (90-100 mg/m2) with simultaneous intravenous sodium thiosulfate delivered to protect against cisplatin-induced nephrotoxicity. One of eight patients (12.5%) receiving intrapleural therapy and nine of 13 patients receiving intraperitoneal therapy demonstrated objective evidence of a clinical response, including three surgically defined major tumor regressions (23%). Patients receiving intrapleural treatment had more advanced disease prior to therapy than those receiving intraperitoneal therapy. It was concluded that intraperitoneal cisplatin is an active treatment program for intra-abdominally localized mesothelioma. Additional investigation of intrapleural cisplatin should be undertaken in a patient population with less advanced disease or following surgical debulking.

Actuarial Analysis↗

Targeted chemoradiation for advanced head and neck cancer: analysis of 213 patients.

BACKGROUND: To determine the survival results, patterns of relapse, and organ preservation effects of a targeted chemoradiation protocol for patients with advanced (stage III-IV) carcinoma of the head and neck. METHODS: Analysis of 213 patients with stage III-IV squamous cell carcinoma treated at UT Memphis between June 1993 and March 1998. Treatment included weekly intra-arterial infusions of cisplatin (150 mg/m(2)/ week x 4) rapidly delivered to the tumor bulk, simultaneous intravenous thiosulfate for systemic drug neutralization, and conventional external-beam irradiation (180-200 cGy/fraction) to a total dose of 68-72 Gy. RESULTS: Tumor response, toxicity, disease control above the clavicle, pattern of relapse, and survival. There were 89 events of grade III-IV toxicity and 6 treatment-related deaths (grade V). Complete response in the primary and regional sites was obtained in 171 of 213 (80%) and 92 of 151 (61%), respectively. The rate of clearance of regional disease after neck dissection was 98%. There were 51 of 195 recurrences (26%): 11 local (5.6%), 5 regional (2.6%), and 35 distant (17.9%). The Kaplan Meier plot projections for overall and cancer-related 5-year survival was 38.8% and 53.6%, respectively, whereas disease control above the clavicle was 74.3%. CONCLUSIONS: We believe this chemoradiation protocol represents an effective management scheme for patients with advanced head and neck cancer with a high rate of organ preservation and possibly improved survival.

Adult↗

Determination of the kinetic parameters of rhodanese by electrophoretically mediated microanalysis in a partially filled capillary.

Electrophoretically mediated microanalysis (EMMA) was applied for the study of kinetic parameters of the bisubstrate enzymatic reaction of rhodanese. The Michaelis constants (K(m)) for both substrates and the effect of temperature on rhodanese reaction were evaluated by means of the combination of the EMMA methodology with a partial filling technique. In this setup, the part of the capillary is filled with the buffer best for the enzymatic reaction whereas, the rest of the capillary is filled with the background electrolyte optimal for separation of substrates and products. The enzymatic reaction was performed in 25 mM N-(2-hydroxymethyl)piperazine-2'-(2-ethanesulfonic acid) (HEPES) buffer (pH 8.5) while the low pH background electrolyte 100 mM beta-alanine-HCl (pH 3.5) was used for separation of substrates and products that are the inorganic anions. The estimated value of K(m) for thiosulfate of 1.30 x 10(-2) M was consistent with previously published values; the K(m) for cyanide of 7.6 x 10(-3) M was determined for the first time. In addition, the type of kinetic mechanism of enzymatic reaction was also elucidated. The finding of the double displacement (ping-pong) mechanism is in accordance with previous literature data. Also, the experimentally determined temperature optimum of the rhodanese-catalyzed reaction around 20-25 degrees C agreed with literature values.

Electrophoresis, Capillary↗

Sulfide oxidation under chemolithoautotrophic denitrifying conditions.

Chemolithoautotrophic denitrifying microorganisms oxidize reduced inorganic sulfur compounds coupled to the reduction of nitrate as an electron acceptor. These denitrifiers can be applied to the removal of nitrogen and/or sulfur contamination from wastewater, groundwater, and gaseous streams. This study investigated the physiology and kinetics of chemolithotrophic denitrification by an enrichment culture utilizing hydrogen sulfide, elemental sulfur, or thiosulfate as electron donor. Complete oxidation of sulfide to sulfate was observed when nitrate was supplemented at concentrations equal or exceeding the stoichiometric requirement. In contrast, sulfide was only partially oxidized to elemental sulfur when nitrate concentrations were limiting. Sulfide was found to inhibit chemolithotrophic sulfoxidation, decreasing rates by approximately 21-fold when the sulfide concentration increased from 2.5 to 10.0 mM, respectively. Addition of low levels of acetate (0.5 mM) enhanced denitrification and sulfate formation, suggesting that acetate was utilized as a carbon source by chemolithotrophic denitrifiers. The results of this study indicate the potential of chemolithotrophic denitrification for the removal of hydrogen sulfide. The sulfide/nitrate ratio can be used to control the fate of sulfide oxidation to either elemental sulfur or sulfate.

Acetates↗

Long-term results of hyperfractionated radiation and high-dose intraarterial cisplatin for unresectable oropharyngeal carcinoma.

BACKGROUND: In this report, the authors present the results from a study of patients with unresectable oropharyngeal squamous cell carcinomas who were treated on a protocol of hyperfractionated radiation and high-dose intraarterial cisplatin (HYPERRADPLAT) at the University of Kentucky. METHODS: The study was designed as a prospective, single-armed case series that was conducted in the setting of a single, academic, tertiary referral center. The patient cohort consisted of 24 previously untreated patients who were diagnosed with unresectable oropharyngeal carcinoma and were treated on the HYPERRADPLAT regimen, which included hyperfractionated external beam radiotherapy (1.2 grays [Gy] twice daily) was given for 5 weeks (60 Gy) followed by high-dose intraarterial cisplatin (150 mg/m2) and sodium thiosulfate. Shrinking "large-field" portals were started on Week 6 and finished on Week 7 with a cumulative dose of 76.8-81.6 Gy. The main outcome measures of the study were the primary and neck response rates, the 2-year and 5-year overall survival and disease-specific survival rates, and acute and late treatment morbidity. RESULTS: The median follow-up was 77 months. Complete response rates at the primary and regional lymph nodes were both 88%. The 2-year overall survival and disease-specific survival rates were 57% and 68%, respectively; whereas the 5-year overall survival and disease-specific survival rates were 33% and 42%, respectively. Two patients had Grade 4 mucosal toxicity, and no patient experienced neurologic or significant hematologic toxicities. Within 1 year of treatment, 58% of patients had used a feeding tube. CONCLUSIONS: The HYPERRADPLAT regimen produced excellent response rates and overall survival rates comparable to those achieved by patients who had unresectable oropharyngeal carcinomas. Tolerance of the therapy was good, and further studies using HYPERRADPLAT with induction therapy may improve outcomes further in this subset of patients with unfavorable disease.

Adult↗

Modified silver staining for immobilized pH gradients.

Silver development of gels containing an immobilized pH gradient has proved difficult so far because the bonded buffers (especially the tertiary amino acrylamido derivatives) tend to absorb silver ions with a resultant heavy background of increasing darkness from the anode to the cathode. We report a variant of silver staining in which thiosulfate is used twice: (i) prior to silver impregnation, at the millimolar level, to enhance sensitivity, and (ii) during development, at the micromolar level, to decrease the background.

Hydrogen-Ion Concentration↗

Rapid superselective high-dose cisplatin infusion for advanced head and neck malignancies.

Advances in vascular radiology techniques for superselective arterial infusions and methods to overcome systemic toxicity from high-dose cisplatin chemotherapy encouraged us to reevaluate the effects of rapid regional cisplatin infusion for patients with head and neck malignancies. Twenty patients (17 carcinomas, three sarcomas) received high-dose cisplatin (100-200 mg/m2) by this method. Fifteen of the 17 patients with upper aerodigestive tract carcinoma are part of an ongoing phase I dose escalation of cisplatin with sodium thiosulfate neutralization. Three additional patients with sarcomas were treated with intra-arterial (IA) cisplatin and systemic Adriamycin. Fifty-three IA infusions were performed without any complications. Only minimal toxicity related to the chemotherapy was observed. The overall response rate for previously untreated patients was nine of 10 (90%) [complete response (CR) 67%; partial response (PR) 33%]. The response rate for patients with recurrent disease was five of eight (63%) (CR 20%, PR 80%). The average length of follow-up is 9.5 months and the actuarial survival rate is 56%. Superselective rapid infusion of high-dose cisplatin for patients with advanced head and neck malignancies is feasible, relatively nontoxic, and may have important applications in multimodality therapy, particularly for patients with bulky primary disease.

Antidotes↗

The inactivation of rhodanese by nitrite and inhibition by other anions in vitro.

Cyanide detoxification in mammals occurs, in part, by sulfur transfer by rhodanese to form the less toxic thiocyanate. Thiosulfate and nitrite are often used in combination for the treatment of cyanide intoxication. This report shows that nitrite can inhibit the rate of sulfur transfer by rhodanese in vitro. Nitrate, chloride, sulfate, and acetate were also examined as inhibitors. Inhibition by nitrite appeared to be more complex than for the other anions tested. Closer examination showed that nitrite can inactivate the sulfur-free rhodanese. Our observation leads to the suggestion that, in vivo, either rhodanese is maintained in its more stable sulfur-substituted form or cellular compartmentalization prevents inactivation by nitrite.

Animals↗

A chaperone-mimetic effect of serum albumin on rhodanese.

Reactivation of denatured rhodanese (thiosulfate:cyanide sulfurtransferase, EC 2.8.1.1) was found to be aided by the presence of serum albumin. Both the rate and the extent of reactivation of the urea-denatured enzyme were optimal at low rhodanese and moderate serum albumin concentrations. Similarly, stabilization of the sulfurtransferase activity of rhodanese that had been partially unfolded at 40 degrees C was aided by the presence of serum albumin. All the observations are in accord with a model in which enzyme that has been partially refolded from the urea-denatured state or partially unfolded thermally interacts directly with serum albumin in a way that prevents rhodanese self-association. Serum albumin thus acts as a molecular chaperone in these systems.

Animals↗

Metabolism of fructose in Thiocapsa roseopersicina.

Thiocapsa roseopersicina strain 6311 grew phototrophically in a mineral medium containing fructose as sole electron donor and carbon source with a doubling time of 11--13 h, provided the mineral medium contained vitamine B12 (50 ng/ml), not more than 20 mM phosphate, and the culture was preincubated in the dark for 24 h. In fructose-grown cells but not in autotrophically grown cells, the cell-protein content was strongly reduced when vitamine B12 was growth limiting, while the carbohydrate content was increased. Growth on fructose as sole carbon source was inhibited by the addition of sulfide or thiosulfate; growth inhibition was relieved in the presence of bicarbonate. No growth on fructose was observed anaerobically in the dark; aerobic growth in the dark was poor. Analysis of enzyme activities in fructose- and acetate-grown cells indicated that fructose was catabolized via fructose-1-phosphate and the EMBDEN-MEYERHOF pathway. The operation of the EMBDEN-MEYERHOF pathway was confirmed by incorporation of 1-14C-, 3-14C-, and 6-14C-fructose into the spirilloxanthin fraction and analysis of its specific radioactivity.

Aerobiosis↗

Inhibition of mucopolysaccharide sulfation.

A method of measuring the inhibition of sulfation in mucopolysaccharides employed the coupled enzyme system of Wortman. This procedure utilized the phenol and mucopolysaccharide sulfotransferases of beef cornea extract. Compounds tested against this system included amino acids, salicylates, 2-mercaptoethylamine and a derivative, heterocyclic ethanethiosulfuric acids, arylsulfonamidoethanethiosulfates, and several other compounds. In general, the salicylates and thiosulfates were inhibitory, with sodiumm 2-(4-acetamidobenzenesulfonamido)-ethanethiosulfate being the most inhibitory and 2-mercaptoethylguanidine trithiocarbonic acid the second most inhibitory. Salicylamide and allopurinol, which have been employed in kidney stone therapy, were inhibitors. Kidney stones have a mucopolysaccharide sulfate matrix, which is involved in their growth.

Animals↗

Cysteine-specific radioiodination of proteins with fluorescein maleimide.

A protocol is described for coupling of carrier-free iodine to protein sulfhydryl groups via fluorescein maleimide. 125I is first coupled to fluorescein maleimide in the presence of chloramine T. Iodination is stopped with sodium thiosulfate, and the iodine-substituted fluorescein maleimide is reacted with free cysteines of the protein. Excess label is then removed by gel-permeation chromatography. The procedure avoids exposition of the protein to oxidative conditions and does not require purification of the labeled carrier reagent. Suitability of the method for a given protein can be evaluated spectrophotometrically without employing radioactivity. It can be applied under denaturing conditions and may be particularly useful with mutant proteins carrying engineered single cysteine residues at sites that are not functionally critical.

Bacterial Proteins↗

Mouse rhodanese gene (Tst): cDNA cloning, sequencing, and recombinant protein expression.

Rhodanese (thiosulfate sulfurtransferase) is expressed at high levels in liver and is involved in the detoxification of cyanide. The full-length cDNA corresponding to the mouse rhodanese gene (Tst), which is located on chromosome 15, was cloned by PCR amplification of a liver cDNA library and subjected to DNA sequencing. Alignment of the rhodanese cDNA sequences from mouse and rat, which we previously cloned (Biochem. J. 275:227-231), revealed 97.3 percent identity at the protein level and 94.6 percent identity at the DNA level. When the mouse and rat cDNAs were expressed under the control of IPTG-inducible promoters in E. coli, the cell extracts exhibited cyanide-metabolizing activity, indicating that both genes encode functional rhodanese molecules.

Amino Acid Sequence↗

Cloning and expression of human liver rhodanese cDNA.

cDNA for the human rhodanese (thiosulfate; cyanide sulfurtransferase, EC 2.8.1.1) was cloned from a human fetal liver cDNA library. Sequencing of the cDNA revealed an open reading frame that encodes a 297-residue polypeptide with a calculated mass of 33,427 daltons. When the rhodanese cDNA was transiently expressed in Escherichia coli and Cos7 cells, the rhodanese activity increased 40-fold and 150-fold, respectively. Sequence homology analysis showed that the human rhodanese is 89.6% identical to bovine, 90.2% identical to rat, 91.2% identical to mouse and Chinese hamster, and 71.4% similar to avian counterparts, respectively, and that rhodanese was highly conserved across evolution.

Amino Acid Sequence↗