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Summary Background Proliferative changes in breast epithelium are an intrinsic aspect in the development of breast cancer, and result in regions of epithelial electrical depolarisation within the breast parenchyma, which can extend to the skin surface. Diagnostic information might be obtained from a non-imaging and non-invasive test based on skin-surface electropotentials. Methods In 661 women, scheduled for open biopsy at eight European centres, we studied whether measurements of breast electrical activity with surface sensors could distinguish benign from malignant breast disease. A depolarisation index was developed. Results We found a highly significant trend of progressive electrical changes according to the proliferative characteristics of the biopsied tissue. Discriminatory information was obtained in both premenopausal and postmenopausal women, and the index was not related to age. The best test performances were for women with palpable lesions. The median index was 0·398 for non-proliferative benign lesions, 0·531 for proliferative benign lesions, and 0·644 for cancer (ductal carcinoma-in-situ and invasive). A specificity of 55% was obtained at 90% sensitivity for women with palpable lesions when a discriminant based on age and the depolarisation index was used. Interpretation This new modality may have diagnostic value, especially in reducing the number of unnecessary diagnostic tests among women with inconclusive findings on physical examination. Understanding and control of the biological variability of these electrical phenomena will be important in the improvement of this test. Studies in populations with a lower cancer prevalence are needed to assess further the diagnostic value of this approach.

Insulin-like growth factor-I (IGF-I) is a ubiquitous hormone that is secreted in both an endocrine and an autocrine/paracrine manner. IGF-I has conventionally been measured in serum; however, transdermal body fluid (TDF) remains as an unexplored biocompartment in which IGF-I also resides and may be more biologically relevant because of its proximity to tissues and cells. The purpose of this study was to compare IGF-I in serum versus IGF-I in TDF before and after 8 weeks of physical training. Twenty-eight healthy men (28 +/- 5 years old, 176 +/- 8 cm tall, weighing 83 +/- 11 kg) had TDF obtained by a novel, minimally invasive method that included the application of continuous vacuum pressure on forearm skin perforated with tiny micropores created by a focused beam from a laser system and also had blood obtained by venipuncture. An enzyme-linked immunosorbent assay measured total IGF-I concentrations. A repeated-measures analysis of variance (biocompartment x time) and Pearson Product Moment Correlation coefficients (Por = 0.05) were used for statistical analyses. Data are presented as mean +/- SE. Total TDF IGF-I was significantly lower than serum IGF-I both before (TDF, 91 +/- 6 ng/mL; serum, 375 +/- 17 ng/mL) and after (TDF, 83 +/- 5 ng/mL; serum, 363 +/- 19 ng/mL) the exercise training. Serum and TDF IGF-I values were not significantly different pre- to post-training. Serum and TDF IGF-I levels were significantly correlated pre-training (r = 0.41), but not post-training (r = 0.34). The percent change between serum and TDF was not correlated (r = 0.09). This study has demonstrated that total IGF-I can be sampled and measured in TDF via a minimally invasive manner and is appreciably (approximately 76%) less than total IGF-I measured in serum. Additionally, the IGF-I measurements in these two biocompartments were not closely associated, possibly indicating an uncoupled, rather than a linked, regulation of IGF-I among the body's biocompartments.

Application of continuous vacuum pressure on skin perforated with tiny micropores created by a focused beam from a low-cost laser system can result in access to a clear, transdermal body fluid (TDF) for the continuous measurement of glucose in vivo. Two clinical studies were performed to assess the feasibility of this approach. In the first study, 56 diabetic subjects were porated on either the arm or abdomen, and glucose was measured in their TDF using a custom assay system contained in a patch that was affixed to the skin above the poration site. The continuous readings of glucose in TDF were compared with fingerstick blood measured every half-hour over a 2-day period, resulting in 1,167 paired data points that yielded a correlation of 0.8745 with 97.75% of the readings in the Clarke Error Grid A and B zones. In a second study, 187 diabetic and 65 nondiabetic subjects had glucose measurements from their TDF made using a commercially available glucose strip and meter. A total of 4,059 data pairs (discrete TDF and capillary blood) were collected over a 2-day period, resulting in a correlation of 0.946 with 99% of the readings in the Clarke Error Grid A and B zones. These studies indicate that TDF drawn through micropores in the stratum corneum of the skin potentially can provide a lesser invasive and continuous method of measuring glucose in diabetic individuals.

A new approach, termed the Biofield test, may have the potential to augment the process of diagnosing breast cancer. This technique is based on the analysis of skin surface electrical potentials measured by an array of specially designed sensors which are placed on the breasts. Measurements are recorded noninvasively and then analyzed using pattern recognition algorithms to produce an immediate and objective assessment of breast tissue in vivo. Initial clinical trials suggests that the test can achieve a sensitivity of approximately 90% and a specificity of 40-50%, which indicates that the test might be useful for excluding cancer when it is, in fact, absent. Although research to date has focused on the differential diagnosis of suspicious breast lesions, future applications could include breast cancer screening, close surveillance and diagnosis of recurrent cancers in breasts previously treated with conservative therapy, and monitoring the effectiveness of breast cancer therapies. Improvements and new applications are expected to occur as additional research and validation in actual clinical settings is performed.

Eye contact between two people often serves as a channel of nonverbal communication. It may signal aggresive or dominating intent, as in a staredown, or it may convey an impression of close bonding, intimacy, or a request for aid, depending on how actors define the situation. Some theories of nonverbal communication assume that mutual gaze is physiologically arousing and that this arousal accounts in part for the efficacy of eye contact as a communication channel. The first experiment reported here shows that mutual gaze does indeed cause more physiological arousal than control conditions of nonmutual gaze. The second experiment demonstrates that an actor can communicate with another person by gazing in such a manner that he can manipulate that person's physiology. A third experiment demonstrates that a subject's response to a mutual gaze is a good predictor of his or her degree of influence (dominance) in subsequent social interaction. These results emphasize the rapid emergence of status differentiation...