Participación de la Cotinina en la abstinencia nicotínica en ratas (Estudio preliminar) / Cotinine participation in chronic nicotinic withdrawal syndrome in rats (Preliminary study)

Numerosos datos clínicos y experimentales han demostrado que la nicotina del tabaco (NI) es la razón de la adicción al tabaco en los seres humanos, a través de la inducción de la tolerancia y la dependencia física. El humo del tabaco contiene otros alcaloides que pueden contribuir a la adicción, como la cotinina (COT). En este estudio se evaluaron los posibles efectos de la COT en ratas durante el síndrome de abstinencia nicotínica midiendo la actividad locomotora espontánea (ALE) utilizando el test del campo abierto. El estudio se llevó a cabo con dos grupos de ratas que recibieron NI 10 mg / kg / día en agua potable durante 120 días (grupos A y B). Luego, en el grupo A, se sustituyó NI por agua potable y en el grupo B, sustituido por COT 12 mg / kg, durante 24 horas en ambos grupos. La actividad locomotora espontánea se registró al final del día 120 (nivel basal) y al final del día 121, al final del período de abstinencia. Los resultados obtenidos se compararon con las mediciones basales. El grupo A mostró diferencias significativas en 3 de los 9 movimientos medidos y el grupo B mostró diferencias significativas en 7 de los 9 movimientos medidos. Cuando el grupo A se comparó con el grupo B sólo 1 movimiento mostró diferencia significativa. Estos resultados sugieren que en la administración crónica de nicotina y en estas condiciones experimentales, la cotinina participa en el síndrome de abstinencia nicotínica

A large amount of clinical and experimental data has shown that tobacco nicotine (NI) is the reason for tobacco addiction in humans, through the induction of tolerance and physical dependence. Tobacco smoke contains other alkaloids that may contribute to addiction, such as cotinine (COT). In this study we evaluated the possible effects of COT in rats during NI abstinence syndrome by measuring spontaneous locomotor activity (SLA) with an open field test. The study was carried out with two groups of rats receiving NI 10 mg / kg / day in drinking water for 120 days (groups A and B). Then, in group A, NI was replaced by drinking water and in group B, substituted by COT, 12 mg / kg, for 24 hours in both groups. Spontaneous locomotor activity was recorded at the end of day 120 (baseline) and at the end of day 121, the end of the abstinence period. The results obtained were compared against the baseline measurements and group A showed significant differences in 3 of the 9 movements measured and group B displayed significant differences in 7 of the 9 movements measured. When group A was compared with Group B only 1 movement showed any significant differences. These results suggest that cotinine participates in the nicotine withdrawal syndrome in chronic nicotine administration under these experimental conditions

In vitro production of llama (Lama glama) embryos by IVF and ICSI with fresh semen.

The interest for South American camelids has increased in the last years. The aim of the present research was to compare the in vitro production of Lama glama embryos using two techniques: in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI). For IVF technique, we compared the effect of adding or not, heparin, penicillamine and hypotaurine as sperm capacitating agents. In the oocyte group subjected to ICSI, activation with or without, ionomycin and 6-dimethylaminopurine (6-DMAP) was assessed. Semen samples were obtained by electroejaculation and incubated at 38 degrees C in a 25% (v/v) collagenase solution. The cleavage and embryo development rates were compared between the different experimental groups. Only the number of cleaved oocytes was less when ICSI with no activation was used (p<0.05).

Sleep habits and accident risk among truck drivers: a cross-sectional study in Argentina.

Road accidents are a major cause of death, and sleep deprivation affects driving skills. We conducted a cross-sectional study to evaluate sleep habits and accident risk in long-haul truck drivers in Buenos Aires, Argentina. Questionnaires regarding sleep habits, snoring, and daytime sleepiness were administered, and a limited physical examination was performed. We obtained 738 complete answers (response rate 85%). Mean sleep hours during working days was 3.76 (SD 2.40). Mean driving hours was 15.9 (SD 5.60) per day. Frequent sleepiness while driving was reported by 43.7% of responders. Sleepiness while driving was associated with Epworth Sleepiness Scale values >10 (odds ratio 1.85, 95% confidence interval = 1.20-2.85). Snoring was reportea by 71% of drivers and was frequent in 43.8%. Snoring more than 3 times a week (odds ratio 1.73, 95% confidence interval = 1.23-2.44), sleepiness while driving (OR 1.92, 95% confidence interval = 1.08-1.96), and Epworth Sleepiness Scale score > 10 (odds ratio 2.53, 95% confidence interval = 1.61-3.97) were independently associated with reporting of accidents or near accidents. Sleep deprivation and long driving shifts were prevalent in our study. Accident risk was associated with frequent snoring, daytime sleepiness, and reporting of sleepiness at the wheel. This study highlights the need of improving working conditions in this highly exposed population.

Early adoption modifies the effects of prenatal stress on dopamine and glutamate receptors in adult rat brain.

Stressful stimuli during pregnancy induce complex effects that influence the development of offspring. These effects can be prevented by environmental manipulations during the early postnatal period. Repeated restraint during the last week of pregnancy was used as a model of prenatal stress, and adoption at birth was used to change the postnatal environment. No differences were found in various physical landmarks, except for testis descent, for which all prenatally stressed pups showed a 1-day delay in comparison with control rats, regardless of the postnatal adoption procedure. Levels of dopamine (DA) D(2) and glutamate (Glu) N-methyl-D-aspartate (NMDA) receptors were differentially regulated in different forebrain regions of cross-fostered adult offspring. Increased concentrations of cortical D(2) receptors detected in stressed pups, raised by a gestationally stressed biological mother, were not detected when the pups were raised by a control mother. Control pups raised by a foster mother whether gestationally stressed or not had higher levels of NMDA receptors in cortical areas. These findings suggest that the normal expression of DA and Glu receptors is influenced by in utero experience and by lactation. The complex pattern of receptor changes reflects the high vulnerability of DA and Glu systems to variations both in prenatal and in postnatal environment, particularly for cortical D(2) receptors and NMDA receptors in cerebral cortex and nucleus accumbens. In contrast, testis descent appears to be more susceptible to prenatal than to postnatal environmental events.

Fermented milk-starch and milk-inulin products as vehicles for lactic acid bacteria.

Formulations using cassava starch or inulin plus milk were fermented with three different lactic acid bacteria (LAB) strains: Lactobacillus plantarum D34, Lactobacillus sp. SLH6, and Streptococcus thermophilus ST4. Growth and acidification were followed in 3% powdered milk (M3), 3% milk-6% starch (M3-S6), and 3% milk-6% inulin (M3-In6). D34 and SLH6 growth was enhanced by starch in M3-S6, when compared to the count (CFU/ml) obtained in M3. Growth of all strains was promoted by inulin. All fermented products showed LAB counts of 8.0 log or higher. Carbohydrate utilization was in agreement with growth and acidification results. The highest increase in CFU in rat feces was observed in M3-S6 fermented with ST4; the D34 fermented product also increased CFU but SLH6 did not, either with starch or inulin. This suggests that ST4 and D34 strains provide a good choice to ferment the proposed formulations in order to obtain a marked improvement of natural intestinal flora.

Cytoprotection by melatonin and growth hormone in early rat myocardial infarction as revealed by Feulgen DNA staining.

OBJECTIVE: To examine the cytoprotective effect of melatonin or recombinant human growth hormone (hGH) on the early phase of a running myocardial infarction in rats by using the Feulgen staining. METHODS: Rats were subjected to surgical ligature of the left coronary artery or its sham-operation and were studied 1.5 3 h later. Melatonin was administered in the drinking water (100 microg/ml water) for 7 days before surgery. Recombinant hGH (2 IU/kg) was given ip at the time of surgery. Feulgen-stained histological cardiac sections were examined by light microscopy and image analysis. RESULTS: Infarcted rats receiving vehicle exhibited large, diffuse cardiac lesions with a marked positivity for Feulgen reaction. About 18 20% of the total area recorded became injured 1.5 or 3 h after infarction, respectively. Infarcted rats treated with melatonin or hGH, or the combination of both, and killed 3 h after surgery, showed cardiac sections with scattered lesions and only a few isolated injured muscle fibers. A similar effectiveness of melatonin and hGH, alone or in combination, to decrease injured area by 86 87% and the number of cardiac lesions by 75 80% was observed. CONCLUSION: A significant cytoprotective effect of melatonin or hGH is demonstrable in an early phase of myocardial infarction in rats.

The molar ratio of retinol-binding protein to transthyretin in the assessment of vitamin A status in adults. Proposal of a cut-off point.

The molar ratio of retinol-binding protein to transthyretin (RBP:TTR) has been proposed as an indirect method to assess vitamin A status in children with inflammation. Neither reference values nor appropriate cut-off point are available for adults. RBP, TTR and retinol were determined in plasma from 100 healthy adults and 31 low-risk surgical patients with no inflammatory response. RBP:TTR percentile distribution from 99 healthy adults with plasma retinol > or = 0.7 micromol/l was: 2.5th = 0.24; 5th = 0.31; 10th = 0.32; 25th = 0.41; 50th = 0.47; 75th = 0.54; 90th = 0.67; 95th = 0.78 and 97.5th = 0.81. In order to define a cut-off point, receiver operating characteristic (ROC) curve was constructed, using plasma retinol as gold standard. ROC curve was based on data from the 131 studied subjects, 11 of whom (8.4%) were classified as deficient on the basis of plasma retinol < 0.7 pmol/l. According to ROC curve criteria, RBP:TTR ratio was considered a good test, the area under the curve being 0.822, p < 0.001. A cut-off-point of < or = 0.37 is proposed to detect vitamin A deficiency in adults, since it allows reaching high sensitivity (81.8%), specificity (79.2%) and predictive value (79.4%). The proposed cut-off point falls between 13th and 14th percentiles.