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T K George

Publications and source records attributed to T K George.

12 recordsLinked to original sources
PubMed2003

Assessment of the probabilistic ecological risk assessment-toxic equivalent combination approach for evaluating pesticide mixture toxicity to zooplankton in outdoor microcosms.

The probabilistic ecological risk assessment-toxic equivalent (PERA-TE) combination approach was recently introduced in response to the increased demand for risk assessment approaches that can accommodate mixtures. The effectiveness and validity of the PERA-TE approach was assessed using two types of pesticide mixtures tested in outdoor microcosms. The first type of mixture consisted of pesticides with similar modes of action (the organophosphorus insecticides chlorpyrifos and diazinon) and the second of pesticides with different modes of action (chlorpyrifos, endosulfan, and trifluralin). To assess the toxicity of, and potential interaction within, each type of mixture, theoretically equitoxic TE mixtures were prepared in different proportional ratios. The TE mixtures were based on the 10th centile of acute toxicity effects distributions (data obtained from the literature) and a factor of the sum of the 90th centile field concentrations extrapolated from exposure distributions based on North American surface water monitoring data. Changes in zooplankton population abundances were used as the effect measure. The binary organophosphorus mixtures were equitoxic and conformed to the concentration addition model. The observed response trends of zooplankton exposed to the mixture of chemicals with different modes of action were a result of the susceptibility of individual taxa to the dominating pesticide in each mixture. Overall, the PERA-TE approach was not effective in predicting the toxicity and interaction of all mixture types and should be limited to assessing mixtures of chemicals with similar modes of action.

Animals↗
PubMed1996

Randomized double-blind prospective trial to evaluate the effects of sargramostim versus placebo in a moderate-dose fluorouracil, doxorubicin, and cyclophosphamide adjuvant chemotherapy program for stage II and III breast cancer.

PURPOSE: To determine the effects of sargramostim (recombinant human granulocyte-macrophage colony-stimulating factor [rhu GM-CSF]) on the incidence, duration, and complications of myelosuppression after moderate-dose fluorouracil, doxorubicin, cyclophosphamide (FAC) adjuvant chemotherapy in patients with node-positive breast cancer. PATIENTS AND METHODS: In this randomized, double-blind, placebo-controlled study, 142 women with stage II and III breast cancer were to receive four 21-day cycles of chemotherapy that consisted of fluorouracil 600 mg/ m2 intravenously (IV), doxorubicin 60 mg/m2 IV, and cyclophosphamide 750 mg/m2 IV on day 1, followed by placebo or GM-CSF 250 micrograms/m2/d daily subcutaneously (SC) on days 3 through 15. All patients received prophylactic ciprofloxacin by mouth when the absolute neutrophil count (ANC) was less than 1,000/microL. RESULTS: Eighty-six percent of GM-CSF patients (n = 62) and 96% of placebo patients (n = 69) completed four assessable cycles of treatment on study. Overall, the median duration of severe neutropenia (ANC < 500/microL) was 2.8 days with GM-CSF and 6.8 days with placebo (P < .001); the duration of ANC less than 1,000/microL was 6.0 versus 9.1 days, respectively (P < .001). Hospitalizations for febrile neutropenia were uncommon in either group: GM-CSF, six; placebo, eight. The only other difference in hematologic toxicity was grade 3/4 thrombocytopenia observed with greater frequency in GM-CSF patients than placebo patients in cycles 3 and 4. GM-CSF increased mean the FAC dose-intensity among patients who completed two or more cycles (P < .001). GM-CSF was generally well tolerated and associated with more injection-site reactions, but less mucositis than placebo. There were no deaths on study. CONCLUSION: GM-CSF significantly enhanced ANC recovery after FAC chemotherapy; it decreased the incidence and duration of associated neutropenia and moderately increased the dose-intensity of adjuvant chemotherapy. Whether these effects will ultimately translate into improved long-term outcome remains to be determined.

Adolescent↗
PubMed1986

Long-term survival in limited-stage small cell lung carcinoma. Experience in Rochester, New York from 1975 to 1981.

All patients with limited-stage small cell lung carcinoma (SCLC) diagnosed between January 1975 and 1981 in Rochester, New York, were collected. One hundred one patients were evaluable. By reviewing an entire community's experience with long follow-up, we were able to describe the response rates and survival in a large unselected population and compare them to results from concurrent cooperative group studies. Median survival for the entire group was 51 weeks, with only 18% alive at 130 weeks. There was no evidence for improvement in response or survival during the 6 years of study. Treatment results in the community as a whole were no different from that seen with cooperative group studies. A group who had initial surgery followed by adjuvant therapy had a significantly better survival and more long-term survivors than those not receiving surgery, but rare long-term survivors were seen with all treatment categories. Except for this small surgical subgroup, no other characteristics could be identified which were predictably associated with long-term disease-free survival. The overall poor survival of patient with localized SCLC suggests a need for the development of novel initial approaches to therapy.

Adult↗
PubMed1986

Ultrasound in the treatment of ankle sprains.

Ultrasound is commonly used in association with other forms of treatment in the management of sprains of the lateral ligament of the ankle. Despite its widespread use there is little scientific evidence to support its role in the management of sprained ankles. We have conducted a prospective, randomized, double-blind trial to compare the results of physiotherapy for sprains of the lateral ligament of the ankle without the use of ultrasound with physiotherapy which included ultrasound. The results in the 154 patients who entered the trial demonstrate that there was no significant difference between the results achieved by the group treated with ultrasound and by those managed without.

Adolescent↗
PubMed1985

Chemotherapy for metastatic Merkel cell carcinoma.

Merkel cell carcinomas (also known as trabecular carcinomas) are primary cutaneous small cell neuroendocrine neoplasms with the potential to metastasize. Control of disseminated disease is therefore important. A case of metastatic Merkel cell carcinoma with an excellent response to chemotherapy is presented. The regimen chosen for this case is similar to that used for bronchogenic small cell anaplastic carcinoma. The reason for selecting this regimen was the common neuroendocrine differentiation and the similar histopathologic features of these two tumors. Only a few reports have described chemotherapy for Merkel cell carcinoma and similar agents were used. These cases are reviewed and critically analyzed.

Adenocarcinoma↗
PubMed1973

Transient response of continuously cultured heterogeneous populations to changes in temperature.

Completely mixed, once-through continuous culture systems of heterogeneous microbial populations of sewage origin were systematically examined for response to changes in reactor temperature. Systems were operated at two dilution rates of 0.125 and 0.25 per h. "Steady state" conditions of the systems were assessed with the reactors operating at 25 C. From this base line, temperature was decreased to as low as 8 C and increased to as high as 57.5 C. Response was assessed in the ensuing transient phase as the system approached a new "steady state." The response was measured by changes in amount and type of carbon source in the reactor effluent as determined by the chemical oxygen demand test, the anthrone test, and gas chromatography. Biological solids concentration and cell composition (protein, carbohydrate, ribonucleic acid and deoxyribonucleic acid) were also determined. These systems responded more favorably to increases than to decreases in temperature. Regardless of the direction of change, the system with the lowest dilution rate (D = 0.125 per h) responded more successfully; i.e., there was less leakage of carbon source in the effluent and less dilute-out of cells during the transient phase.

Bacteria↗