Sentinel lymph node biopsy with intraoperative touch imprint cytology (TIC) in breast cancer: experience of a mild-volume center.

Although considered the gold standard in treatment of EBC, sentinel node biopsy still remains a debated issue. What to do in case of positive sentinel node and the need of intraoperative histological examination are the most topics under discussion. In this study we have retrospectively evaluate our case series of 359 sentinel node biopsy in the managing of breast cancer from January 2011 to December 2018, focusing on the TIC technique for performing intraoperative examination. It results in 12,8% "FALSE NEGATIVE" rate, in which only 4,2% in macrometastases, with an overall sensitivity of 68,4% (macrometastases: 86%; micrometastases: 11%), overall specificity of 98,7% and an overall accuracy of 89,7%. The intraoperative examination of SLN allows to reduce delayed surgery procedures and greater therapeutic safety in case of mastectomy. The TIC method can be considered valid, simple and rapid in identifying macrometastases, also allowing to avoid under-staging. The low sensitivity for micrometastases is not a limit, considering that recent evidence has drastically reduced the indications for ALND in these cases. Further ongoing trials and the possible validation of NOMOGRAMMS and SCORE are necessary to identify low risk cases in which to definitively omit the ALND and/or even the SLNB itself.

Gas formation. Formation temperatures of thermogenic and biogenic methane.

Methane is an important greenhouse gas and energy resource generated dominantly by methanogens at low temperatures and through the breakdown of organic molecules at high temperatures. However, methane-formation temperatures in nature are often poorly constrained. We measured formation temperatures of thermogenic and biogenic methane using a "clumped isotope" technique. Thermogenic gases yield formation temperatures between 157° and 221°C, within the nominal gas window, and biogenic gases yield formation temperatures consistent with their comparatively lower-temperature formational environments (<50°C). In systems where gases have migrated and other proxies for gas-generation temperature yield ambiguous results, methane clumped-isotope temperatures distinguish among and allow for independent tests of possible gas-formation models.

Oxygen isotope ratios of PO4: an inorganic indicator of enzymatic activity and P metabolism and a new biomarker in the search for life.

The distinctive relations between biological activity and isotopic effect recorded in biomarkers (e.g., carbon and sulfur isotope ratios) have allowed scientists to suggest that life originated on this planet nearly 3.8 billion years ago. The existence of life on other planets may be similarly identified by geochemical biomarkers, including the oxygen isotope ratio of phosphate (delta(18)O(p)) presented here. At low near-surface temperatures, the exchange of oxygen isotopes between phosphate and water requires enzymatic catalysis. Because enzymes are indicative of cellular activity, the demonstration of enzyme-catalyzed PO(4)-H(2)O exchange is indicative of the presence of life. Results of laboratory experiments are presented that clearly show that delta(18)O(P) values of inorganic phosphate can be used to detect enzymatic activity and microbial metabolism of phosphate. Applications of delta(18)O(p) as a biomarker are presented for two Earth environments relevant to the search for extraterrestrial life: a shallow groundwater reservoir and a marine hydrothermal vent system. With the development of in situ analytical techniques and future planned sample return strategies, delta(18)O(p) may provide an important biosignature of the presence of life in extraterrestrial systems such as that on Mars.

Patterns of drug, alcohol and tobacco use among high school students in Santiago, Chile.

A survey using a self-administered questionnaire, based on a sample of 1,240 students from four public schools in Santiago, showed that 70.1 per cent of the students used alcohol, 56.3 per cent tobacco, 7.3 per cent cannabis, 2.5 per cent tranquillizers, 1.9 per cent stimulants and 0.7 per cent tranquillizers together with stimulants. Frequent alcohol consumption was found among 14.5 per cent of the students, 11.1 per cent of them smoked more than six cigarettes a day and 1.4 per cent smoked cannabis more than once a week. Consumption of these substances were more frequent among students who came from presumably more affluent residential neighbourhoods. Easy access to drugs played an important role in the occurrence of drug abuse.