Use of short-term bio-impedance for gastric motility assessment.

Gastric motility (GM) has been assessed using bio-impedance (BI) techniques in the time domain using short term recordings and analyzing mainly the median of the area under the fast Fourier transform (FFT) spectra. The BI technique has been applied to the gastric system mainly for gastric emptying (GE) studies. However, gastric motility evaluation using BI has not been fully implemented. In this study, we propose the use of the BI technique for the evaluation of gastric motility considering global features of the fast FFT spectra. The study was performed in eleven healthy subjects who were evaluated in fasting and postprandial conditions. The results indicate that the use of the median of the area under the FFT spectra is equivalent to the use of the main peak of the spectra to determine the changes in gastric motility from the fasting to the postprandial state. This demonstrates that BI is a valid technique for gastric motility evaluation in short time recordings.

Raman spectroscopy and multivariate analysis of serum samples from breast cancer patients.

Serum samples were studied using Raman spectroscopy and analyzed through the multivariate statistical methods of principal component analysis (PCA) and linear discriminant analysis (LDA). The blood samples were obtained from 11 patients who were clinically diagnosed with breast cancer and 12 healthy volunteer controls. The PCA allowed us to define the wavelength differences between the spectral bands of the control and patient groups. However, since the differences in the involved molecules were in their tertiary or quaternary structure, it was not possible to determine what molecule caused the observed differences in the spectra. The ratio of the corresponding band intensities were analyzed by calculating the p values and it was found that only seven of these band ratios were significant and corresponded to proteins, phospholipids, and polysaccharides. These specific bands might be helpful during screening for breast cancer using Raman Spectroscopy of serum samples. It is also shown that serum samples from patients with breast cancer and from the control group can be discriminated when the LDA is applied to their Raman spectra.

The colon transit time in different phases of the menstrual cycle: assessed with biomagnetic technique.

Twenty measurements of the colon transit time (CTT) were performed by biomagnetic technique in five young women. Subjects were assessed during 12 hours a day for four phases of the menstrual cycle (MC): early follicular (EF), days 1-4 of the MC; late follicular (LF), days 9-14; early luteal (EL), days 15-18; and late luteal (LL), days 23-28 of the MC. Comparison intra and inter-subjects were made. The results of a t test for dependent samples, demonstrate that women with regular MC had higher CTT on LF (3.29 +/- 1.40 m/hr) than on LL phases of the MC (1.28 +/- 0.4 m/hr) t = 3.22, p = 0.04. Also we found differences from EL to LL phases of the MC (4.49 +/- 1.72 m/hr vs. 1.29 +/- 0.35 m/hr, t = 3.05, p = 0.05). However, in a patient with polycystic ovary syndrome (PCOS), we found a CTT of 3.1 m/hr on day 3; 2 m/hr on day 15; and 0.8 m/hr on day 30 of the MC. The time of the magnetic marker displacement was higher on days 3 of the MC, if we compared these values with those from women with regular MC (1.8 +/- 0.67 m/hr). We demonstrate that biomagnetic technique is a powerful method to assess changes in CTT presented in female subjects during the MC. Furthermore, the results found for the CTT in different phases of the MC of the females subjects, are in agreement with those reported by using other techniques.

Factors associated with the sexual experiences of underprivileged Mexican adolescents.

This study investigated factors associated with the sexual experiences of 523 underprivileged Mexican adolescents. Approximately 41% of the males and 24% of the females were sexually active, with more than half not using contraceptives. Multivariate logistic regression analysis revealed that sexual activity was strongly associated with age, knowledge about sexually transmitted diseases, and attitudes toward sexuality. Positive affective responsiveness in the family was associated with sexual activity and number of sexual partners. Family problem solving and roles were also associated with sexual activity. The use of contraceptives was negatively related to affective involvement between parents, and being a victim of sexual abuse was negatively associated with number of persons in the family. These findings support the notion that affective environment within the family is a factor in adolescent sexuality.

Knowledge and attitudes toward sexuality in adolescents and their association with the family and other factors.

Family structure and function and their association with knowledge and attitudes toward sexuality, contraception, and sexually transmitted diseases (STD) were studied in 918 students and 312 adolescents working in factories. Unmarried workers reported higher rates of sexual activity than did students (30.9% vs. 21.8%, p = .04 for males; 12.9% vs. 6.0%, p = .005 for females). Among sexually active males, 33.3% of students and 30.7% of workers used contraception, compared with 27.5% of female students and 9.5% of female workers. Workers were from larger families than students, and the male and female workers had lower scores for knowledge on sexuality, contraception, and STD than did students. Multiple stepwise regression showed that age and schooling of the parents were associated with knowledge and attitudes in the students. In workers, the position of the child in the family was a negative regressor for attitudes and knowledge on sexuality in males, and for knowledge on contraception and STD in females. In regard to family function, the significant factors were compromise between the parents, positive affective response, communication within the family, problem solution, and control of behavior. It was concluded that female workers are at higher risk for unwanted pregnancies and STD. The factors associated with knowledge and attitudes were age, schooling of the parents, mother working out of home, position of the adolescent in the family, and the diverse aspects of family function.