Inchworm bipedal nanowalker.

Nanowalkers take either inchworm (IW) or hand-over-hand (HOH) gait. The IW nanowalkers are advantageous over HOH ones in force generation, processivity and high-density integration, though both gaits occur in intracellular nanowalkers from biology. Artificial IW nanowalkers have been realized or proposed, but all rely on different 'head' and 'tail' to gain an adventitious direction. Here we report an inherently unidirectional IW nanowalker that is a biped with two identical legs (i.e., indistinguishable 'head' and 'tail'). This walker is made of DNA, and driven by a light-powered G-quadruplex engine. The directional inchworm motion is confirmed by operating the walker on a DNA duplex track that is designed to show a distinctive fluorescence pattern for IW walkers as compared to HOH ones. Interestingly, this walker exhibits stride-controlled IW-to-HOH gait switch and direction reversal when the track's periodic binding sites have wider and wider separation. The results altogether present an integrated mechanism for implementing nanowalkers of different gaits and directions on molecular tracks, optical potentials or even solid-state surfaces.

Ticks (Acari: Ixodidae) of the state of Amazonas, Brazil.

The tick fauna of Brazil is currently composed by 72 species. The state of Amazonas is the largest of Brazil, with an area of ≈ 19% of the Brazilian land. Besides its vast geographic area, only 19 tick species have been reported for Amazonas. Herein, lots containing ticks from the state of Amazonas were examined in three major tick collections from Brazil. A total of 5933 tick specimens were examined and recorded, comprising 2693 males, 1247 females, 1509 nymphs, and 484 larvae. These ticks were identified into the following 22 species: Amblyomma cajennense sensu lato, Amblyomma calcaratum, Amblyomma coelebs, Amblyomma dissimile, Amblyomma dubitatum, Amblyomma geayi, Amblyomma goeldii, Amblyomma humerale, Amblyomma latepunctatun, Amblyomma longirostre, Amblyomma naponense, Amblyomma oblongoguttatum, Amblyomma ovale, Amblyomma rotundatum, Amblyomma scalpturatum, Amblyomma varium, Dermacentor nitens, Haemaphysalis juxtakochi, Ixodes cf. Ixodes fuscipes, Ixodes luciae, Rhipicephalus microplus, Rhipicephalus sanguineus sensu lato. Ticks were collected from 17 (27.4%) out of the 62 municipalities that currently compose the state of Amazonas. The following four species are reported for the first time in the state of Amazonas: A. coelebs, A. dubitatum, H. juxtakochi, and Ixodes cf. I. fuscipes. The only tick species previously reported for Amazonas and not found in the present study is Amblyomma parvum. This study provides a great expansion of geographical and host records of ticks for the state of Amazonas, which is now considered to have a tick fauna composed by 23 species. It is noteworthy that we report 1391 Amblyomma nymphs that were identified to 13 different species.

Biodosimetry using micronucleus assay in acute partial body therapeutic irradiation.

Biological dosimetry provides information on the absorbed dose and its distribution in the body for an early assessment of irradiation consequences in exposed individuals. In this study, an effort has been made to see the applicability of biological dosimetry using micronuclei assay for dose estimation in therapeutic irradiation of cancer patients in acute high dose partial body irradiation. Dose estimation in partial body irradiations was done on the basis of Dolphin's contaminated Poisson method, using the in vitro dose response calibration curve. The equivalent whole body dose and the dose to the irradiated part of the body were estimated to be 1.8+/-0.1 Gy and 6.4+/-0.3 Gy, respectively. The estimated percentage of irradiated blood and the fraction of cells exposed were 41.5+/-1.6% and 10.4+/-0.8%, respectively. The estimated fraction of irradiated cells was comparable with the actual volume of irradiation.

Biological estimation of dose in hemi-body irradiation of cancer patients by cytogenetic analysis.

The objective of this study was to estimate equivalent whole body dose and dose to the irradiated region in hemi-body irradiation of cancer patients using chromosome aberrations and micronuclei techniques. The frequency of unstable chromosome aberrations and micronuclei was studied in peripheral blood lymphocytes of cancer patients before and after hemi-body irradiation. The mean estimated equivalent whole body dose was 3.74 +/- 0.16 Gy and 4.07 +/- 0.15 Gy from dicentrics and micronuclei frequency in lymphocytes after hemi-body irradiation. The mean dose to the irradiated region from unstable chromosome aberrations was estimated to be 6.85 +/- 0.2 Gy and 6.79 +/- 0.26 Gy using Dolphin's contaminated Poisson dispersion analysis and the Qdr method, respectively. The mean dose to the irradiated region from micronuclei frequency was 7.04 +/- 0.25 Gy by Dolphin's method. There was a slight underestimation of mean dose to the irradiated part in vivo. The percentage of irradiated blood and fraction of the cells exposed could be estimated using the contaminated Poisson method.

Biodosimetry using chromosome aberrations in human lymphocytes.

In vitro dose-response calibration curves for (60)Co gamma rays have been established for unstable chromosome aberrations in human peripheral blood lymphocytes. The observed dose-response data were fitted to a linear quadratic model. The calibration curve parameters were used to estimate the equivalent whole-body dose and dose to the irradiated region in partial body irradiation of cancer patients. The derived partial body doses and fractions of lymphocytes irradiated were in agreement with those estimated from the radiotherapy regimes.

Micronuclei evaluation of reduction in neoadjuvant chemotherapy related acute toxicity in locally advanced lung cancer: an indian experience.

BACKGROUND: Lung cancer is the most common cancer in the world accounting for 17.6% cancers worldwide. The AAR i n I ndian population varies f r om 0.98-15.55. The aim of t he present study was to analyze areduction in neoadjuvant chemotherapy related acute toxicity in locally advanced lung cancer (stage IIIA and III B) using Wobe Mugos E and its evaluation using micronuclei as a cytogenetic marker. Micronuclei, which are cytoplasmic fragments of DNA, have been used as a biological dosimeter to assess DNA damage. MATERIAL AND METHODS: Fourty patients of locally advanced NSCLC were randomized into two study groups between 2001-2003. One group received neoadjuvant chemotherapy using Cisplatin and Etoposide. The other group received neoadjuvant chemotherapy using Cisplatin and Etoposide along with Wobe Mugos E which is a proteolytic enzyme preparation. A study of micronuclei frequency was done pre and post chemotherapy in both groups. RESULTS: Thirty eight patients were available for final evaluation. Anemia was the most common hematological toxicity observed. Nausea and vomiting were the most common non -hematological toxicity seen. Wobe Mugos E was found to reduce the incidence of leucopenia (p = 0.005), nausea (p=0.004), vomiting (p= 0.003), sensory neuropathy (p = 0.032) and treatment related depression (p= 0.005). A reduction in micronuclei was seen in patients in patients on Wobe Mugos E. (p =0.01). CONCLUSION: Neo-adjuvant chemotherapy related acute toxicity is a major problem in patients with advanced lung cancer. A reduction in micronuclei frequency shows Wobe Mugos E to be effective in reducing chemotherapy related acute toxicity.

Effect of amifostine on toxicities associated with salvage combination chemotherapy.

PURPOSE: To determine the effect of amifostine on the safety and efficacy of chemotherapy in heavily pretreated patients and to study the side effects of amifostine delivered to patients receiving chemotherapy at a dose of 740 mg/m2. MATERIAL AND METHODS: Thirty-two patients of histologically proven (recurrent) malignancy who had previously received > or = 6 cycles of chemotherapy and developed grade II or grade III toxicities during treatment with salvage chemotherapy were eligible. These patients were given Injection Amifostine 740 mg/m2 as a 15 min. i.v. infusion 30 min. prior to combination chemotherapy. RESULTS: A total of 85 cycles were administered with amifostine and 46 cycles without amifostine. The side effects during amifostine infusion were hypotension (9.6% cycles), vomiting (20% cycles), somnolence (33% cycles), sneezing (8% cycles), and flushing (19% cycles). The chemotherapy toxicities were reduced from 47.7% to 30.6% for grade II and from 28% to 9.4% for grade III in case of gastrointestinal toxicity. Similarly there was improvement in the mean hemoglobin level from 8.2 gm% to 10.01 gm%, mean total leucocyte count from 2,280/mm3 to 3,600/mm3. CONCLUSION: Amifostine has an excellent safety profile and is well tolerated by the patients. Pretreatment with Amifostine resulted in fewer treatment related delays and dose reduction resulting in better tolerance to salvage chemotherapy.