Simplifying two-vector mechanics calculations for challenging tooth movements.

The purpose of this article was to describe a simple graphical driven method for determining the necessary two-vector mechanics (TVM) as an alternative solution to the ideal or single force. In orthodontics, some tooth movements are difficult to achieve, mainly because of the impossibility of getting the point of application for the necessary force system. Given two points in biomechanically accessible areas, adding together two vectors applied to those points will result in an equivalent force system. The method was developed based on previous research, 3,880 hypothetical cases were analyzed to determine the trends between the resulting forces and their relative locations. A graphical driven TVM method (GTVM) for establishing the necessary TVM is presented in a manner that combine different procedures from the traditional method that simplify the analysis and may allow the user to perform more complex orthodontic cases making easier to compare systems of force equivalents.

Tumorigenic effect mediated by ROS/eicosanoids and their regulation on TP53 expression in a murine mammary gland adenocarcinoma.

The aim of this study was to investigate the in vivo and in vitro effects of dietary ω-6 and ω-3 polyunsaturated fatty acids (PUFAs) and their derivatives on the expression of TP53 and their relationship with cellular proliferation and death in a murine mammary adenocarcinoma model. BALB/c mice were divided in three diet groups: chia oil (ChO) rich in ω-3, corn oil (CO) rich in ω-6/ω-3 and safflower oil (SO) rich in ω-6 and subcutaneously inoculated with LMM3 mammary tumor cell line. Results demonstrated that diets with higher concentration of omega-6 PUFAs induced an increment of linoleic and arachidonic acid on tumor cell membranes increasing ROS liberation, 12(S)-HHT generation, TP53, Ki67 expression and cell proliferation. However, diets enriched with high content in omega-3 PUFAs induced higher tumor cell apoptosis and tumor infiltration of CD3+ lymphocytes, lowest cell viability and proliferation. Dietary omega-3 PUFAs nutritional intervention can be used as a potential preventative strategy to inhibit the molecular signaling pathways involved in the mammary tumor growth process as the TP53.

Maternal and postnatal high-fat diets with high ω6 : ω3 ratios affect the reproductive performance of male offspring in the mouse.

High-fat diets (HFDs) are an acknowledged risk factor for male subfertility, but the underlying mechanisms remain unclear. In the present study we compared the effects of two HFDs with different ω6:ω3 ratios, one enriched with soy oil (SOD; ω6:ω3=9.62) and another enriched with sunflower oil (SFOD; ω6:ω3=51.55), with those of a commercial diet (CD; ω6:ω3=19.87), supplied from pregnancy to adulthood, on morphometric parameters and reproductive performance in adult male mice (recommended ω6:ω3 for rodents=1-6). Bodyweight was significantly higher in the SFOD than CD group, and relative testicular weight was significantly lower in the SFOD than the other two groups. SFOD altered sperm performance: it reduced sperm viability (mean±s.e.m.; 76.00±1.35% vs 82.50±1.45% and 80.63±1.00% in the SFOD vs CD and SOD groups respectively; P<0.05) and increased the percentage of immature spermatozoa (71.88±7.17% vs 51.38±5.87% and 48.00±5.72% in the SFOD vs CD and SOD groups respectively; P<0.05). The epididymal ω6:ω3 ratio was higher in the SFOD versus CD and SOD groups, whereas the unsaturation index was higher in the SOD and SFOD groups than in CD group. Sperm membrane integrity was diminished in both the SOD and SFOD groups, but there was no difference in sperm reactive oxygen species production in these two groups compared with the CD group. The fertilisation rate was lower in the SFOD compared with the CD and SOD groups. In conclusion, although both HFDs affected sperm quality, the fertilising ability was more altered by the excessive dietary ω6:ω3 ratio than by the net ω6 content.

[Rotator cuff tear: correlation between ultrasound and arthroscopic findings]. / Ruptura del manguito rotador: correlación de hallazgos ultrasonográficos y artroscópicos.

OBJECTIVE: To analyze the preoperative shoulder ultrasound (US) findings in patients with a diagnosis of rotator cuff (RC) tear and correlate them with the arthroscopic findings. METHODS: Retrospective analysis of a consecutive series of patients with a diagnosis of RC pathology in whom US was performed and who underwent surgery (shoulder arthroscopy). The US/arthroscopic findings were correlated with Fisher's and chi2 tests. RESULTS: The total number of patients was 53. We identified US/arthroscopic correlation in 22/34 cases for the total tears (64.7%) and in 7/19 cases for the partial tears (36.8%) (p = 0.048). Overall correlation (total and partial tears) was seen in 29/53 patients (54.7%). Of the 24 patients without correlation, 11 (45.8%) had ultrasound reports of tendinitis; 75% of the cases in this group had findings of partial supraspinous tear during arthroscopy (p = 0.006). CONCLUSION: US shows an appropriate correlation with the diagnosis of RC total tear confirmed with arthroscopy, and the correlation is significantly lower for partial tears. In cases of an ultrasound-diagnosed lesion, such as tendinitis, most cases showed a partial tear during arthroscopy.

Serie de paciente con escabiosis tratados con azufre precipitado al 6% / Series of patient with scabies treated with 6% precipitated sulfur

OBJETIVOS: reportar los resultados de la estrategia que incluye "el tratamiento tópico con azufre precipitado al 6% sumado a medidas no farmacológicas" en la población de Villa Verde, Pilar, Buenos Aires, Argentina. MÉTODOS: Serie de casos tratados entre Marzo de 2007 y marzo de 2008 de una muestra de conveniencia integrada por toda la población con signos y síntomas sugestivos de escabiosis durante dicho período. RESULTADOS: Fueron incluidos 161 pacientes, pero sólo se pudo realizar la evaluación completa en 110 de ellos (68,3%). De éstos, 74 se encontraba curado a los 15 días de iniciado el tratamiento y otros 23, al mes, lo que implica una tasa global de curación de 88%. Sólo 12,7% de la muestra evaluada presentó efectos adversos. El 20% de los encuestados percibió la intervención como de bajo costo, el 32,6 de costo moderado y el 47,5 alto. El autorreporte de adherencia al tratamiento farmacológico fue de 95% y del no farmacológico, 96%. CONCLUSIONES: Estos resultados contribuyen a avalar una estrategia terapéutica ampliamente utilizada en nuestro medio (por su bajo precio y amplia disponibilidad), que por el momento posee escasa evidencia científica y es utilizada por motivos fundamentalmente empíricos.

OBJECTIVES: Report the results of the strategy that includes "the topical treatment with precipitated sulfur at 6% plus non-pharmacological measures" in the population of Villa Verde, Pilar, Buenos Aires, Argentina. METHODS: A series of cases treated between March 2007 and March 2008 of a sample of convenience integrated by the entire population with signs and symptoms suggestive of scabies during this period. RESULTS: A total of 161 patients were included, but only 110 of them could complete the complete evaluation (68.3%). Of these, 74 were cured 15 days after starting treatment and another 23, a month, which implies an overall cure rate of 88%. Only 12.7% of the sample evaluated had adverse effects. 20% of respondents perceived the intervention as low cost, 32.6 moderate cost and 47.5 high. Self-reported adherence to pharmacological treatment was 95% and non-pharmacological self-report was 96%. CONCLUSIONS: These results contribute to endorse a therapeutic strategy widely used in our environment (due to its low price and wide availability), which at the moment has little scientific evidence and is used for fundamentally empirical reasons.

[Serovars of Salmonella enterica subspecies enterica and its antimicrobial resistance in slaughterhouse pigs]. / Serovariedades de Salmonella enterica subespecie enterica en porcinos de faena y su resistencia a los antimicrobianos.

A study was carried out in order to determine the prevalence of Salmonella and its serovars among porcine slaughterhouses, to evaluate the antimicrobial resistance profiles and to know the presence of class 1 integrons as possible reservoir of resistance. From a total of 386 samples from four porcine slaughterhouses of Buenos Aires and Santa Fe Provinces (Argentina), 93 (24.1%) Salmonella enterica subspecies enterica strains were identified, 52 (55.9%) from cecal contents and 41 (44.1%) from ileocecal lymph nodes. Thirteen serovars of S. enterica were found, the most prevalent were: S. Schwarzengrund, S. Heidelberg, S. subspecie I 6,8:e,h:-, S. Derby and S. Bredeney. Fifteen antimicrobials by the agar dilution method were tested: amikacin, gentamicin, ciprofloxacin, cephalotin, cefotaxime, enrofloxacin, fosfomycin, polimixin-B, tetracycline, chloramphenicol, streptomycin, trimethoprim-sulfamethoxazole, ampicillin, nitrofurantoin, and nalidixic acid. According to the CIM determination, 73% Salmonella enterica subspecies enterica strains were sensible to all the antimicrobials tested. Antimicrobial resistance was observed to tetracycline in 24 (25.8%) of 93 strains, to chloramphenicol in 22 (23.7%), to streptomycin in 22 (23.7%), to trimethoprim-sulfamethoxazole in 20 (21.5%), to ampicillin in 18 (19.4%), to nitrofurantoin in 3 (3.2%) and to nalidixic acid in 3 (3.2%). Some isolates of S. Typhimurium, S. Heidelberg, S. Derby, S. Orion showed multidrug resistance and carried the class 1 integrase gene. The highest percentage of resistance corresponded to the antimicrobials currently used in veterinary and porcine farms.

Serovariedades de Salmonella enterica subespecie enterica en porcinos de faena y su resistencia a los antimicrobianos / Serovars of Salmonella enterica subspecies enterica and its antimicrobial resistance in slaughterhouse pigs

Se realizó un estudio para determinar la prevalencia de Salmonella y sus serovariedades en cerdos de faena, para evaluar sus perfiles de resistencia a los antimicrobianos y para conocer la presencia de integrones de clase 1 como posibles reservorios de resistencia. A partir de un total de 386 muestras de porcinos provenientes de cuatro frigoríficos de las provincias de Buenos Aires y de Santa Fe (Argentina), se identificaron 93 (24,1%) cepas de Salmonella enterica subespecie enterica, 52 (55,9%) de contenido cecal y 41 (44,1%) de nódulo linfático ileocecal. Se hallaron 13 serovariedades de S. enterica, las más prevalentes fueron S. Schwarzengrund, S. Heidelberg, S. subespecie I 6,8:e,h:-, S. Derby y S. Bredeney. Se probaron 15 antimicrobianos por el método de dilución en agar: amikacina, gentamicina, ciprofloxacina, cefalotina, cefotaxima, enrofloxacina, fosfomicina, polimixina-B, tetraciclina, cloranfenicol, estreptomicina, trimetoprima-sulfametoxazol, ampicilina, nitrofurantoína y ácido nalidíxico. Según se estableció mediante la determinación de la CIM, el 73% de las cepas de S. enterica subespecie enterica fueron sensibles a todos los antimicrobianos probados. Se observó resistencia a tetraciclina en 24 (25,8%) de las 93 cepas, a cloranfenicol en 22 (23,7%), a estreptomicina en 22 (23,7%) a trimetoprima-sulfametoxazol en 20 (21,5%), a ampicilina en 18 (19,4%), a nitrofurantoína en 3 (3,2%) y a ácido nalidíxico en 3 (3,2%). Algunos aislamientos de S. Typhimurium, S. Heildelberg, S. Derby y S. Orion presentaron multirresistencia y portaban el gen de la integrasa clase 1. Los mayores porcentajes de resistencia correspondieron a los antimicrobianos habitualmente utilizados en veterinaria y en las explotaciones porcinas.

A study was carried out in order to determine the prevalence of Salmonella and its serovars among porcine slaughterhouses, to evaluate the antimicrobial resistance profiles and to know the presence of class 1 integrons as possible reservoir of resistance. From a total of 386 samples from four porcine slaughterhouses of Buenos Aires and Santa Fe Provinces (Argentina), 93 (24,1%) Salmonella enterica subspecies enterica strains were identified, 52 (55,9%) from cecal contents and 41 (44,1%) from ileocecal lymph nodes. Thirteen serovars of S. enterica were found, the most prevalent were: S. Schwarzengrund, S. Heidelberg, S. subspecie I 6,8:e,h:-, S. Derby and S. Bredeney. Fifteen antimicrobials by the agar dilution method were tested: amikacin, gentamicin, ciprofloxacin, cephalotin, cefotaxime, enrofloxacin, fosfomycin, polimixin-B, tetracycline, chloramphenicol, streptomycin, trimethoprim-sulfamethoxazole, ampicillin, nitrofurantoin, and nalidixic acid. According to the CIM determination, 73% Salmonella enterica subspecies enterica strains were sensible to all the antimicrobials tested. Antimicrobial resistance was observed to tetracycline in 24 (25,8%) of 93 strains, to chloramphenicol in 22 (23,7%), to streptomycin in 22 (23,7%), to trimethoprim-sulfamethoxazole in 20 (21,5%), to ampicillin in 18 (19,4%), to nitrofurantoin in 3 (3,2%) and to nalidixic acid in 3 (3,2%). Some isolates of S. Typhimurium, S. Heidelberg, S. Derby, S. Orion showed multidrug resistance and carried the class 1 integrase gene. The highest percentage of resistance corresponded to the antimicrobials currently used in veterinary and porcine farms.

Participation of Na/Ca-exchanger and sarcoplasmic reticulum in the high [K]-protection against ischaemia-reperfusion dysfunction in rat hearts.

AIM: Na/Ca-exchanger (NCX) and sarcoplasmic reticulum (SR) roles during the protection by a cardioplegic solution (25 mm K and 0.5 mm Ca, CPG) against ischaemia-reperfusion was studied. METHODS: Contractile performance (CP) and high energy phosphates contents (HEP) were evaluated in isolated ventricles from rats. They were pre-treated with Krebs (C) or CPG and submitted to no-flow ischaemia and reperfusion (I-R). KB-R7943 5 microm (inhibitor of NCX in reverse mode), 8 mm caffeine and ionic changes were used pre-ischaemically to evaluate each pathway role. RESULTS: During R, CP recovered to 77 +/- 8% of basal in CPG-hearts vs. 55 +/- 8% (P < 0.05) in C-ones. CPG avoided the increases in end diastolic pressure (LVEDP) and in PCr/ATP ratio during I-R. Low [Na]o (78 mm) under both, CPG-2 mm Ca and C, increased further the LVEDP during I-R. LVEDP was also transiently increased by caffeine-CPG, but not modified by KB-R7943. The recovery of CP during reperfusion of CPG-hearts was decreased either, by caffeine (to approximately 75%), low [Na]o-2 mm Ca-CPG (to approximately 40%) and KB-R7943 (to approximately 16%). CONCLUSIONS: CPG protected hearts from ischaemic contracture by attenuating the fall in ATP and removing diastolic Ca by means of NCX in forward mode. Moreover, CPG induces higher CP recovery during reperfusion by participation of SR and NCX in reverse mode. This work remarks the use of CPG based on the functional role of these Ca handling-mechanisms in a pathophysiological condition as ischaemia-reperfusion.

Development of an HPLC method for determination of metabolic compounds in myocardial tissue.

The determination of adenine nucleotides and creatine compounds has great importance in the characterization of ischemic myocardial injury and post-ischemic recovery. It was developed by an HPLC method for the quantification of creatine (Cr), creatine phosphate (CrP), hypoxanthine (HX), AMP, adenosine (Ad), ADP and ATP in isolated perfused rat hearts. The chromatographic conditions were: RP 18 column; mobile phase composed by KH(2)PO(4) (215 mM), tetrabutylammonium hydrogen sulfate (2.3mM), acetonitrile (4%) and KOH (1M 0.4%); flow rate 1 ml min(-1); temperature 25 degrees C; injection volume 20 microl; detection at 220 nm and height peak (HP) as the integration parameter. The method was validated by means of linearity and sensitivity evaluations, using calibration curves done with five concentration levels of each compound. The limits of quantification (LOQ) were also determined. The system precision was calculated as the coefficient of variation for five injections for each compound tested. The purity of the peaks was established using enzymatic peak shift analysis with hexokinase and creatine kinase and also comparing HP at various wavelengths. Frozen hearts were homogenized with a mechanical homogenizer for 3 min at 0 degrees C added with 5 ml of 0.4N HCLO(4). After precipitation with 0.8 ml of 2M KOH the extract was shaked for 2 min and later centrifuged at 0 degrees C for 10 min. The supernatant was kept on ice, filtrated and injected into the HPLC system. The results show that the method for the determination of Cr, CrP, HX, AMP, Ad, ADP and ATP by HPLC here described has good linearity, LOQ, precision, specificity and is simple and rapid to perform.

Producción de unidades lingüísticas y no lingüísticas en el habla de pacientes con enfermedad de Alzheimer / Linguistic and nonlinguistic unit production in the speech of Alzheimer patients

Estudios en sujetos con enfermedad de Alzheimer (EA) revelan diferencias en su producción del habla comparada con la de personas mayores normales. El hallazgo más frecuente ha sido un menor número de unidades lingüísticas y una mayor duración de las pausas en el habla. En este artículo, se presentan los resultados de las unidades lingüísticas y no lingüísticas durante entrevistas grabadas a 16 pacientes con EA y 21 senescentes normales. Los diagnósticos fueron efectuados por psiquiatras, (Proyecto "Demencias asociadas a edad" Facultad de Medicina, Universidad de Concepción, Chile) mediante procedimiento multifásico: tamizaje validado para deterioro cognitivo, criterios clínicos estandarizados para demencia y escalas de estadio, igualmente validadas. Los pacientes, mostraron una producción de secuencias de habla más pequeñas y más turnos en la conversación. Esto concuerda con hallazgos anteriores que identifican la variable duración de las pausas como la más discriminante entre los grupos, lo que sugiere que la búsqueda de palabras y la planificación del discurso estarían alteradas en ellos, debido a los procesos degenerativos propios de la EA (AU)

Noncognitive symptoms in Alzheimer disease and caregivers distress in Chile.

This study describes the profile of noncognitive symptoms in Chilean AD patients and its effects on the caregiver's mental health. In a sample of 26 urban dwelling AD patients, 21 of them women, age range 63-90 years, diagnosed using NINCDS-ADRDA, the intensity and frequency of noncognitive symptoms and caregivers distress was assessed using NPI. Seventeen caregivers were first degree relatives. The most prevalent symptoms were apathy, irritability, and anxiety. The least were euphoria, hallucinations, and disinhibition. The most stressful conditions were disinhibition and agitation: the best well-tolerated were euphoria and anxiety. Caregivers responded most frequently with feelings of concern and depression. Few of them reported to be ashamed. These results may reflect cultural differences and represents the first description of this reality in Chile.

Spanish validation of the Syndrom Kurztest (SKT).

There is an urgent need in multinational studies for efficient and sensitive tests for the evaluation of dementias. These tests are used to investigate the regional characteristics of dementias, providing possible insight into the different etiologies of the disorders. These tests are also utilized to assess the outcome of treatment interventions at multinational levels. We validated and standardized the Syndrom Kurztest, a brief European neuropsychological test, in a population of elderly Chileans, possessing high levels of illiteracy. In our sample, the SKT was found to be an effective instrument for the diagnosis of dementias, and for differentiating mild-moderate from severe degrees of the disease. There was a good correlation between the scores on the SKT and the age of the participants, but the gender and the years of schooling had no effect. The test is a useful contribution to the study of dementias, found in the aging developing world, particularly because it can be used in illiterate populations.

Comparative bioavailability of diltiazem in prolonged-release oral preparations.

This study was conducted to compare the bioavailability of two prolonged-release pharmaceutical forms containing 300 mg of diltiazem. The test formulation is a new design of tablets with a hydrophilic matrix, and the reference formulation is capsules containing prolonged liberation microgranules, in the same dose, that are commercially available in the pharmaceutical market. Diltiazem plasma concentrations were analyzed by high-performance liquid chromatography (HPLC), which involves solid-phase extraction for plasma sample preparation. Twelve healthy volunteers participated in the study, which had a single-dose, two-treatment, two-sequence-crossover, randomized design. The preparations were compared using pharmacokinetic parameters such as the area under the plasma concentration-time curve AUC(0-36), peak plasma concentration Cmax, and Cmax/AUC(0-36) ratio as a measure for the absorption rate. No statistically significant difference was observed for any of the parameters, and the 90% confidence intervals calculated for the ratio of the logarithmically transformed AUC(0-36) and Cmax/AUC(0-36) values of both formulations were within the bioequivalence limit of 0.80-1.25. Moreover, an in vitro study of dissolution according to USP 23 was conducted, and the in vitro parameters were calculated.

Apolipoprotein E polymorphism in elderly Chilean people with Alzheimer's disease.

As a part of the WHO Age-Associated Dementia Project, Chile has been participating in a cross-national survey on dementia frequency and determinants since 1989. In the present study, apolipoprotein E (ApoE) polymorphism genotypes have been compared in 95 patients with Alzheimer's disease (AD) (mean age 80.7; 95% CI 79.2-82.2, range 66-97) and 187 healthy people (mean age 78.2; 95% CI 77.2-79.2, range 65-93). Isoelectric focusing and immunoblotting with anti-human ApoE polyclonal antibody were used to determine the distribution of ApoE genotypes. Dementia was diagnosed according to DSM-III-R and ICD-10 clinical criteria. The diagnosis of probable or possible AD was made according to the NINCDS-ADRDA criteria. The ApoE allele frequencies in healthy people were calculated to be epsilon2 = 0.07, epsilon3 = 0.74 and epsilon4 = 0.19. In the probable AD disease group, the frequencies were epsilon2 = 0.08, epsilon3 = 0.52 and epsilon4 = 0.40. The odds ratio (OR) for epsilon4 carriers compared with non-epsilon4 carriers was estimated to be 2.9 (95% CI 1.7-5.1). Taking the genotype epsilon3/epsilon3 as the reference group, the OR for the epsilon4/epsilon4 genotype was estimated to be 12.8 (95% CI 3.9-47.6) and for epsilon3/epsilon4 subjects it was 2.4 (1.3-4.5). These results support the association between ApoE epsilon4 allele with late-onset AD in a Chilean population.

First analytical chemistry study on drug abuse in the Buenos Aires (Argentina) University students.

One hundred samples were randomly selected from urine specimens collected from Buenos Aires University students, 50 males and 50 females, whose ages ranged from 19 to 47 years. Cocaine (COC), cannabinoids (CNNs), amphetamines (AMs), benzodiazepines (BZDs), barbiturates (BBTs), opiates (OPs) and salicylates (SAs) were searched for by ELISA, FPIA, normalized TLC, HPLC and GC/MS techniques. The presence of COC was detected in five samples, CNN in two and SA in twelve. No evidence of AMs, BZDs, BBTs or OPs was found.

Manipulacion de antibioticos parentales por el profesional de Enfermeria en un hospital de tercer nivel / Parental antibiotics: the role of nursing professional

Con este trabajo se pretendió identificar la manipulación de los antibióticos parenterales que realizan las enfermeras de los servicios de pediatría y la unidad de recién nacidos (URN) en un hospital de tercer nivel. Se seleccionó una muestra de 15 profesionales que laboran en los servicios ya mencionados en el segundo semestre de 1997. Para la recolección de datos se diseñó y aplicó una guía de observación estructurada y un cuestionario de conocimientos. Entre los hallazgos se encontró que las enfermeras poseen buenas bases teóricas pero no son aplicadas en la práctica, observando que el 84 por ciento poseen buenos conocimientos y que sólo el 62 por ciento manipulan correctamente los medicamentos

Chronotropic, inotropic and lusitropic effects of capsaicin on isolated rat atria.

This work includes results on chronotropic, inotropic and lusitropic changes induced by capsaicin on isolated rat atria. As regards spontaneous frequency, it was stimulated from 10(-9) M up to 7 x 10(-7) M of capsaicin. A simultaneous depression in developed force (F) showed a significant correlation with this positive chronotropic effect up to 7 x 10(-8) M of capsaicin, which is the result of the negative staircase phenomenon in the rat heart. The correlation was lost at 2 and 7 x 10(-7) M of capsaicin since in spite of the sustained increase in atrial rate the decrease in F was reversed and then depressed again at 2 and 7 x 10(-6) M of capsaicin without changes in frequency. A concentration of capsaicin that overcome the negative staircase phenomenon, 5 x 10(-7) M, was tested as unique dose resulting in stimulation of the chronotropic, inotropic and lusitropic states of the atria. Percentual differences with respect to control values were maximal after 1-3 minutes for frequency (10 +/- 3%), F (29 +/- 4%), maximal velocity of force development (+F = 50 +/- 12%) (in all cases +F and -F bold indicates +F and -F, respectively), and maximal velocity of relaxation (-F = 64 +/- 13%); a positive lusitropic effect was significant after 8-10 minutes (+F/-F = 17 +/- 7%). Capsaicin did not affect the rat atria in the presence of 10(-6) M of ruthenium red, a blocker of capsaicin activation of sensory nerves, indicating that the stimulatory effects were entirely mediated by the release of neurotransmitters and that this concentration of capsaicin was not deleterous "per se". Capsaicin elicited similar inotropic responses in electrically driven isolated atria (+F = 41 +/- 9%) but the positive lusitropic effect was lost suggesting that capsaicin-induced increases in -F are limited at a frequency higher than the spontaneous frequency (11 +/- 6 vs. 32 +/- 4%, respectively). 10(-6) M of CGRP8-37, an antagonist of CGRP1 receptors, suppress the stimulatory effects of capsaicin on atrial contraction. In summary, atrial rate as compared to atrial contraction is more sensitive to the neurotransmitter released by capsaicin, which results in mechanical effects expressing the negative staircase phenomenon in the rat at low concentrations of capsaicin. The positive chronotropic, inotropic and lusitropic responses elicited by capsaicin are mediated by the release of neurotransmitters from sensory fibbers and no deletereous effects of capsaicin "per se" became evident when the release of neuropeptides was prevented. Atrial contraction was depressed at higher capsaicin concentrations than the one showing stimulatory effects. Stimulation of atrial contractility is mediated by activation of CGRP receptors.

Dietary deficiency or enrichment of essential fatty acids modulates tumorigenesis in the whole body of cobalt-60-irradiated mice.

The effect of dietary polyunsaturated fatty acids (PUFAs) on whole body-induced tumorigenesis was assayed in mice fed on essential fatty acid sufficient (EFAS) or essential fatty acid deficient (EFAD) diets following cobalt-60 irradiation. Four groups of mice were maintained, one on a control stock diet and three on experimental diets: a) without added fat (fat free, FF); b) containing 5% olein (O), rich in n-9; and c) containing 5% corn oil, rich in n-6 EFA (CO). Only mice fed on FF or O diets showed clinical and biochemical signs of EFAD. Total incidence of tumors showed an increase in FF (P < 0.02) and O (P < 0.03) mice. Tumors developed mostly in the liver in each of the EFAD groups (P < 0.001). Slight promoting activity on lung tumorigenesis was recorded in the CO group when this parameter was compared in EFAD and EFA sufficient mice. It may be concluded that, when a tumor initiator injures the body as a whole, EFAD, achieved either through a fat-free or an oleic-supplemented diet, behaves as a general promoting condition for tumorigenesis. The borderline tumorigenic effect of n-6 corn oil on the lungs suggests that this effect, when present, is target specific.