Application of impedance spectroscopy for the characterization of hams during post-salting / Aplicación de la espectroscopia de impedancia para la caracterización de jamones durante el post-salado

Background: The smart control for food and feed technologies consist in the development of new methods that facilitate the control of productive processes guaranteeing the quality and safety of agrofood products. The importance given to this research line is a clear indicator of the interest of all of the agents implicated in promoting the introduction of innovative technologies. The goal is to implement new, fast, economical, analytical techniques, which constitute a real alternative to traditional control procedures. Objective: The aim of this study was to evaluate the use of an electronic sensor based on the impedance spectroscopy technique for the characterization of hams during the post-salting step (8, 10, 12 and 14 weeks). Materials and methods: 60 hams from three different categories (fat, semi-fat and lean), were tray salted under the conditions of a company (xNaCl = 0.11 g/g dry matter). For each time, samples were first evaluated with the electronic method (non-destructive analysis) and then analytical determinations of: mass variation, moisture content, fat content, salt content and water activity were performed on each ham in different zones. The electric data were evaluated using Principal Component Analysis (PCA) and regression with Partial Least Squares (PLS) through the analytical data. Results: The PCA analysis discriminated between the different evaluated zones. At eighth week 79.06% of the variance was explained and at tenth week, the 82.53%. No relation was observed for the different ham categories. The correlation between the impedance signal and the analytical determinations showed the best cross validation coefficient (R2CV) values for moisture content (0.75) and water activity (0.73). Conclusions: The impedance spectroscopy technique generated different signals between the zones of analysis during the first two post-salting times, eight and ten weeks, in which physicochemical differences were also observed as a consequence of the variation in the salt concentration between zones.

Antecedentes: El control inteligente de los alimentos y las tecnologías alimentarias, consiste en el desarrollo de nuevos métodos que facilitan el control de los procesos productivos y garantizan la calidad y seguridad de los productos agroalimentarios. La relevancia concedida a esta línea de investigación es un claro indicador del interés de todos los agentes implicados en impulsar la introducción de tecnologías innovadoras. La meta es implementar nuevas técnicas analíticas rápidas y económicas, que constituyan una alternativa real a los procedimientos tradicionales de control. Objetivo: Evaluar el uso de un sensor electrónico basado en la técnica de la espectroscopia de impedancia para la caracterización de jamones durante el post-salado (8, 10, 12 y 14 semanas). Materiales y métodos: 60 jamones de tres categorías diferentes (grasa, semigrasa y magra) fueron salados en bandeja bajo las condiciones de una empresa (xNaCl = 0.11 g/g base seca). A cada tiempo establecido, las muestras seleccionadas se evaluaron utilizando el método electrónico (análisis no destructivo) y se realizaron determinaciones analíticas de: variación de masa, contenido de humedad, contenido de grasa, contenido de sal y actividad de agua, en diferentes zonas de la muestra. La información electrónica se analizó mediante análisis de componentes principales (PCA) y correlaciones (PLS) entre la señal de impedancia y las determinaciones analíticas. Resultados: El análisis de PCA discriminó entre las diferentes zonas de análisis evaluadas. A la octava semana se explicó un 79.06% de la varianza de las muestras y a la décima, un 82.53%. No hubo relación entre las diferentes categorías de jamones. La correlación estadística de la señal de impedancia con las determinaciones analíticas mostró los mejores valores de coeficiente de validación cruzada (R2CV) para el contenido de humedad (0.75) y la actividad de agua (0.73). Conclusiones: La técnica de espectroscopia de impedancia generó señales diferentes entre las zonas de análisis durante los dos primeros tiempos de post-salado, ocho y diez semanas, en los que también se observaron diferencias fisicoquímicas como consecuencia de la variación en la concentración salina entre zonas.

Smoking as a risk factor for preinvasive and invasive cervical lesions in female sex workers in Venezuela.

OBJECTIVES: To determine whether the number of cigarettes smoked per day and years of smoking were risk factors for preinvasive and invasive cervical lesions in Venezuelan female sex workers. METHODS: The clinical history of 438 female sex workers (FSWs) was taken and each received a gynecological examination, a Pap smear, and a colposcopic examination. A colposcopically-guided cervical biopsy was taken when the epithelium appeared abnormal. RESULTS: The FSWs' mean age was 32.16+/-8 years. Age at first sexual intercourse was 15.9+/-2 years, parity was 4.1+/-2.3, live births were 3+/-3, and age at first delivery was 16.6+/-4.7 years. Cervical biopsies were performed in 84 FSWs. Sixty-four of them (76.2%) had preinvasive or invasive lesions and 47 (73.4%) were current smokers (Relative Risk) (RR), 1.26; 95% confidence interval (CI), 1.02-1.55; P<0.03]. FSWs who smoked more than 20 cigarettes per day had an increased RR to get a premalignant or malignant cervical lesion (RR, 1.27; 95% CI, 1.02-1.52; P<0.03). There was no statistically significant difference between FSWs who smoked 20 cigarettes or more per day and FSWs who smoked less than 20 cigarettes per day (RR, 1.36; 95% CI, 0.81-2.29; P<0.25). FSWs who had been smoking for 5 years or more were at risk to develop preinvasive or invasive cervical lesions (RR, 1.37; 95% CI, 1.01-1.86; P<0.04). CONCLUSIONS: The risk for FSWs to develop preinvasive or invasive cervical lesions increased with the number of cigarettes they smoked per day and their years of smoking.

Cyto-colpo-histological Study in Sexual Workers.

OBJECTIVE: To determine the false-negative, false-positive, sensitivity, specificity, negative predictive value (NPV), and positive predictive value (PPV) rates of Pap smears and colposcopy in sexual workers. MATERIALS AND METHODS: Four hundred thirty-eight prostitutes were given a gynecological examination, Pap smear, and colposcopic examination of the cervix. A cervical biopsy was taken under colposcopic guidance when there was abnormal epithelium. RESULTS: There were 81 premalignant and malignant lesions. Twenty-two Pap smear reports were abnormal: 17 CIN1, four CIN2, and one CIN3. Pap smears had a 14.4% false-negative rate, 0.9% false-positive rate, sensitivity 22.2%, specificity 98.8%, NPV 84.4%, and PPV 81.8%. Eighty-four biopsies were taken from abnormal colposcopic findings, and 96.4% were reported as premalignant and malignant lesions. Colposcopy had a 0.8% false-positive rate, sensitivity 100%, specificity 99.2%, NPV 100%, and PPV 96.4%. CONCLUSIONS: Pap smear had a low-sensitivity and colposcopy had a high sensitivity and specificity.

The zoapatle II--botanical and ecological determinants.

A collection of Montanoa (Cerv) specimens was conducted throughout Mexico. Twenty-one specimens were classified, some of them grown in the greenhouse and transplanted in an agricultural experimental field station in the Valley of Mexico. In vitro uterotonic potency was assayed and the results expressed as equivalents of oxytocine, by using estrogenized guinea pig uterine strips. A great variation of uterotonic potency was observed among the wild plants. A clear decrease and uniformity of uterotonic potency was found in plants grown in the experimental field. The study points out the importance of ecological variations in expression of the plant's biological activity.

PIP: 21 specimens of the zoapatle Montanoa (Cerv) plant were collected from sites throughout Mexico with a variety of climatic, humidity, soil composition, and altitude conditions to assess their uterotonic properties. Some plants were then grown in an agricultural experimental field station of the National Institute of Agricultural Research, where all the variables were known, allowing for a valid comparison between species and plants. In vitro uterotonic potency was assayed and the results expressed as equivalents of oxytocin. The wild plants were found to vary greatly in uterotonic potency, perhaps reflecting differences in ecological conditions. The most active uterotonic zoapatle aqueous crude extract was the Montanoa frutescens, and the least active was M. mollissima, the former having approximately 4 times the uterotonic potency of the latter. The plants grown in the agricultural field station showed a considerable decrease in uterotonic potency, but valid comparisons must await assay in winter to match the stage in the plant life when the wild samples were assayed. Plant age, the part of the plant from which the uterotonic principle is extracted, climate, altitude, and soil constituents are other possible influences on uterotonic potency. A sample of the zoapatle aqueous crude extract with the highest uterotonic potency will be assayed for its luteolytic activity in an animal model.

The zoapatle III--biological and uterotonic properties of aqueous plant extract.

Differences in uterotonic activity were observed between zoapatle Montanoa (Cerv.), plants growing in their natural habitat and plants growing in an experimental agricultural plot. Details of an in vitro analogic model for assaying uterotonic potency in guinea pig strips is described. Important species differences on the uterine response to zoapatle aqueous crude extract were noticed in rats, hamsters, guinea pigs, cats and Rhesus monkeys. The need for proper biological evaluation of chemical substances already isolated from zoapatle specimens, is mentioned, and the advantages of working with zoapatle specimens grown under controlled ecological conditions are pointed out.

PIP: An in vitro analogic method for comparing the uterotonic potency of dialysed zoapatle aqueous crude extract (DZ-ZACE) with oxytocin is described. Uterine strips from estrogenized guinea pigs were selected as the appropriate animal model after trials with estrogenized rats, hamsters, cats, and Rhesus monkeys. Results of the in vitro uterotonic effect produced by 21 different zoapatle Montanoa plants collected from different parts of Mexico and grown in an experimental agricultural field station indicate considerable difference, with less variation in uterotonic oxytocin/equivalents among the plants grown at the field station than in wild specimens. The general reduction in uterotonic potency of plants grown at the field station may be due to differences in the time of collection: wild specimens were collected in winter 1980, while field station specimens were collected just after flowering in early summer 1981. The findings clearly demonstrate the influence of the plant environment on the expression of biological response. Because of its lack of toxicity, abundance, ease of production, and the availability of an efficient analogic in vitro assay for the evaluation of relative uterotonic potency, ZACE may eventually be the source of a new agent to intercept pregnancy.

The zoapatle IV--toxicological and clinical studies.

The zoapatle aqueous crude extract has been used in Mexico for the last 5 centuries for the induction of labor, treatment of post-partum bleeding problems, and as a menses inducer. Today, it is sold in street markets, and its long documented history of use by humans could be taken as indirect evidence of a lack of toxicity. Rigorous pharmacological and clinical studies described here, fully confirm the empirical observations.

PIP: For the last 5 centuries in Mexico the zoapatle aqueous crude extract (ZACE) has been used for the induction of labor, treatment of postpartum bleeding problems, and as a menses inducer. Despite widespread and continuous use of ZACE on the part of the Mexican population and the absence of documented side effects or toxicological phenomenon associated with its use, it was decided to undertake acute and subacute toxicological studies prior to clinical studies in volunteer subjects in Mexico and Sweden. Plant specimens for the studies were collected in different batches at several locations near the National University of Mexico. The material was properly identified at the university's botanical herbarium. ZACE was prepared by boiling 100 g of dry leaves in 400 ml of distilled water for 20-30 minutes, filtered through gauze, and the final volume obtained by using a rotor evaporator 50-60 degrees Centigrade with light negative pressure, to 100 ml. The ZACE concentration was 1 g dry leaves/ml. The extract was tested in an "in vitro" guinea pig uterine strip assay. For the 1st series of studies in Mexico, 60 female Sprague-Dawley rats, 8 weeks old, and 6 mongrel female dogs, were used. 25 rats were used as control and 35 tested. All animals were maintained in a controlled laboratory condition with 12/12 hour light/darkness cycle. 2 dogs served as control, and 4 were treated. All experimental animals received, through a rubber cannula, 5 ml/KG of ZACE daily. Control animals received distilled water. Each animal was carefully observed for 30 minutes after fluid intake. At the end of the study, the rats were sacrificed with ether, and the dogs with phenobarbital. Complete anatomapathological examinations were performed. 6 control and 8 treated rats died during the study, and all deaths were associated with accidental placement of the rubber cannula. Behavioral changes were observed in neither rats nor dogs throughout the study. No changes were recorded in body weights. No macro nor microscopic alteration was found in either group of rats. Results of hematological examinations did not differ between the 2 groups. It was concluded that ZACE is devoid of acute and subacute toxicity. In addition to the clinical observations reported by Gallegos in Mexico, where 10 normally menstruating volunteer women received 15 or 30 gm/day of zoapatle dry leaves extract orally for 3-9 consecutive days without clinical evidence of any side effects, clinical investigations were conducted by Landgren et al. in Sweden. 6 women in early pregnancy were given zoapatle; 6 women in early pregnancy served as a control group. A significant dilation of the cervix was found in each of the subjects treated with zoapatle decocts. A menstrual like cramp was reported by all and bleeding occurred in 4 of 6 subjects. No gastrointestinal symptoms were observed. No pain or bleeding nor significant dilatation of the cervix was evident prior to surgery. Immediately prior to vacuum extraction, cervical dilatation was less than 5 mm in all subjects. In sum, ZACE was devoid of toxic complication or side effects.

The zoapatle V--the effect of kauradienoic acid upon uterine contractility.

Kauradienoic acid was obtained from the hexanic extract of M. tomentosa (Cerv) leaves by chromatographic separation. This substance influenced the in vitro contractility of the rat, dog and guinea pig uterine strips. It also induced strong contractions of the guinea pig uterus in vivo when administered intravenously, without changes on arterial blood pressure. The effects produced by the plant infusion, the hexanic extract and pure species were compared. The hexanic of other utero-active compounds in M. tomentosa in addition to those already described is discussed.

PIP: The investigation of uterotonic effects of the hexanic extract (HE) of M. tomentosa leaves, as well as that (-)-kaura-9(11), 16-dien-19-oic acid, henceforth referred to as kauradienoic acid (KA) is described. Pregnant and nonpregnant female Wistar rats, guinea pigs, and dogs were used in this study. Strips obtained from 5 animals had spontaneous rhythmical contractions constant in amplitude and frequency. Muscular tone and frequency of contractions were notably increased by addition of 20 ul/ml of zoapatle aqueous crude extract (ZACE). The preparation returned to the original spontaneous contractility pattern after washing with a modified Ringer solution. Strips obtained from 5 gravid guinea pigs showed scarce spontaneous contractility which was strongly augmented by addition of ZACE. Regular spontaneous contractions were observed in over 30 assays of uterine strips obtained from 5 nongravid rats. The addition of ZACE drastically inhibited the spontaneous contractility. Constant and reproducible results were obtained in gravid rats by addition of ZACE. A gradual decrease in amplitude of contractions was observed. The addition of ZACE depressed the uterine contractility (UC) of 8 uterine strips from 2 animals. The addition of ZACE in gravid dogs in 8 uterine strips was accompanied by an increase of muscular tonus and frequency. A gradual decrease in the amplitude of the rat spontaneous UC was an effect produced by the HE. Addition of water suspension of HE elicited an immediate increase of guinea pig's uterine motility. Results were similar with those observed with ZACE. KA inhibited the "in vitro" rat UC and increased the "in vitro" guinea pig contractions of uterine musculature in a similar fashion as observed with ZACE and HE.