Biomedical subjects

José Martín

Publications and source records attributed to José Martín.

16 recordsLinked to original sources

PubMed2007

Pregnant female lizards Iberolacerta cyreni adjust refuge use to decrease thermal costs for their body condition and cell-mediated immune response.

Lizards often respond to increased predation risk by increasing refuge use, but this strategy may entail a loss of thermoregulatory opportunities, which may lead to a loss of body condition. This may be especially important for pregnant oviparous female lizards, because they need to maintain optimal body temperatures as long as possible to maximize developmental embryos rate until laying. However, little is known about how increased time spent at low temperatures in refuges affects body condition and health state of pregnant female lizards. Furthermore, it is not clear how initial body condition affects refuge use. Female Iberian rock lizards forced to increase time spent at low temperatures showed lower body condition and tended to show lower cell-mediated immune responses than control females. Therefore, the loss of thermoregulatory opportunities seems to be an important cost for pregnant females. Nevertheless, thereafter, when we simulated two repeated predatory attacks, females modified refuge use in relation to their body condition, with females with worse condition decreasing time hidden after attacks. In conclusion, female lizards seemed able to compensate increased predation risk with flexible antipredatory strategies, thus minimizing costs for body condition and health state.

Analysis of Variance↗

PubMed2006

Decentralisation and convergence in health among the provinces of Spain (1980-2001).

This study measures the process of convergence in the state of health among the provinces and regions of Spain during 1980-2001 in order to analyse the possible influence of the decentralisation of healthcare management to the regions in this period. Sigma and beta convergence models, traditionally employed in macroeconomics, have been used, taking Life Expectancy at Birth (LEB) and Infant Mortality (IM) as health indicators. The analysis was carried out at two territorial levels: provinces and regions. The results reveal that the process of decentralisation either does not affect convergence or leads to divergence in health. Indeed, in the case of IM the so-called change of role scenario seems to have occurred. Thus, certain provinces with initially poor indicators have improved, overtaking those that were originally in a better position. The final result, however, is of greater dispersion than initially.

Empirical Research↗

PubMed2006

Refuge use: a conflict between avoiding predation and losing mass in lizards.

Prey often respond to predation risk by increasing refuge use, but this strategy may entail a loss of body condition. Factors responsible for this loss of body condition remain unclear. Also how prey deal with refuge use to cope with predation risk without incurring costs of body condition, and how initial body condition affects refuge use remain barely known. We analyzed in the field whether adult Iberolacerta cyreni lizards modify their escape strategies and refuge use in areas with different levels of habitat deterioration and ecotourism pressure, which represent different levels of predation risk, and the consequences of changes in antipredator behavior to body condition. Lizards inhabiting deteriorated areas, where risk is higher, remained closer to refuges, but decreased time spent hidden in refuges after attacks, probably to maintain similar body condition than lizards inhabiting natural areas. We performed two laboratory experiments to isolate potential costs of refuge use that might affect the body condition of male lizards: a) a decrease of the efficiency of digestion due to low temperatures inside refuges and/or b) a reduction in food intake. Results suggest that refuge use is costly in terms of body condition due to reduced food intake, but the loss of efficiency of digestion seems unimportant. Lizards modified refuge use in relation to their body condition, with lizards with worse condition decreasing time hidden after predatory attacks. We concluded that lizards compensated for increased predation risk with flexible antipredatory strategies, coping with risk without incurring costs for body condition.

Adaptation, Physiological↗

PubMed2006

Vitamin D supplementation increases the attractiveness of males' scent for female Iberian rock lizards.

Evolutionary theory proposes that signals used in sexual selection can only be stable if they are honest and condition dependent. However, despite the fact that chemical signals are used by many animals, empirical research has mainly focused on visual and acoustic signals. Vitamin D is an essential nutrient for lizards, but in some lizards its precursor (cholesta-5,7-dien-3-ol=provitamin D) is found in femoral gland secretions, which males use for scent marking and intraspecific communication. By allocating provitamin D to secretions, males might need to divert vitamin D from metabolism. This might be costly and condition dependent. We tested whether diet quality affected chemical signals of male Iberian rock lizards (Lacerta monticola) and its consequences for sexual selection. After experimental supplementation of dietary vitamin D, males increased the proportion of provitamin D in femoral secretions. Further experiments showed that females detected these changes in males' signals by chemosensory cues, and discriminated provitamin D, and changes in its concentration, from similar steroids (i.e. cholesterol) found in secretions. Moreover, females preferred areas scent marked by males with more provitamin D in their secretions. This mechanism would confer honesty to chemical signals of male lizards, and, thus, females may rely on it to select high-quality males. We suggest that the allocation of vitamins and other essential nutrients to either visual (e.g. carotenoids) or chemical ornaments might be the common basis of honest sexual displays in many animals.

Analysis of Variance↗

PubMed2006

Reliable signaling by chemical cues of male traits and health state in male lizards, Lacerta monticola.

In spite of the importance of chemoreception in social organization and sexual selection of lizards, there is a lack of general knowledge on how the characteristics of chemical signals mediate these behaviors. Moreover, it is unknown which are the mechanisms that might confer honesty to the information provided by chemical signals. We analyzed here whether characteristics of the lipophilic fraction of femoral gland secretions of Lacerta monticola male lizards can be related to the morphology, physical condition, and health state of the sender. Our results indicated that some male traits, such as body size, number of blue spots, and number of femoral pores and their level of fluctuating asymmetry, were related to variability in the relative proportions of some lipophilic chemical compounds found in secretions. Thus, conspecifics could obtain reliable information on the producer of a scent mark based on chemicals alone, and this might be the basis of female choice observed in this lizard. Moreover, only males with a greater T-cell immune response had higher proportions of two steroids (ergosterol and dehydrocholesterol) in their femoral secretions, which might suggest that the signal is honest and costly to produce. We suggest that only high-quality males could divert these compounds from metabolism to secretions in order to produce an exaggerated and honest "chemical ornament."

Animals↗

PubMed2006

[Utility of magnetic resonance cholangiography prior to cholecystectomy in acute biliary pancreatitis].

AIM: To analyze the role of magnetic resonance cholangiography (MRC) in candidates for cholecystectomy after acute biliary pancreatitis (ABP). METHODS: We performed a prospective study of patients with mild ABP (Atlanta criteria) admitted to our hospital from January 2004 to March 2005. Diagnosis of ABP was based on clinical features, serum amylase levels more than 3 times higher than the upper level of normality, and gallstones detected by ultrasonography. In all patients, MRC was performed preoperatively. If positive for common bile duct stones (CBDS), endoscopic retrograde cholangiopancreatography (ERCP) with endoscopic sphincterotomy (ES) was performed, followed by laparoscopic cholecystectomy (LC). When MRC was negative, LC was performed directly. Intraoperative cholangiography was not routinely performed . RESULTS: Of the 31 patients admitted, 27 were included (mean age 66.4 +/- 18 years, 78% female). Four patients were excluded: 2 refused to undergo cholecystectomy and two had severe ABP. The mean interval between onset of ABP and cholecystectomy was 1.7 months +/- 1.2. Three patients (11.1%) experienced recurrence within 4 weeks of the index admission. MRC revealed CBDS in four patients (14.8%). In 3 patients, all the gallstones were removed by ERCP and ES. In one patient, 12 gallstones were retrieved but attempts to remove a stone from the cystic duct were unsuccessful. One patient with preoperative CBDS was readmitted 4 weeks after cholecystectomy due to recurrence. Another patient with negative findings on preoperative MRC was also readmitted with postcholecystectomy ABP. Twenty-five of the 27 patients (93%) have remained asymptomatic after cholecystectomy (median follow-up: 16 months [8-22 months]). CONCLUSIONS: MRC should not be routinely used in the preoperative evaluation of patients with ABP but is an accurate tool in selected patients with this disease.

Acute Disease↗

PubMed2005

Female Iberian wall lizards prefer male scents that signal a better cell-mediated immune response.

In spite of the importance of chemoreception in sexual selection of lizards, only a few studies have examined the composition of chemical signals, and it is unknown whether and how chemicals provide honest information. Chemical signals might be honest if there were a trade-off between sexual advertisement and the immune system. Here, we show that proportions of cholesta-5,7-dien-3-ol in femoral secretions of male Iberian wall lizards (Podarcis hispanica) were related to their T-cell-mediated immune response. Thus, only males with a good immune system may allocate higher amounts of this chemical to signalling. Furthermore, females selected scents of males with higher proportions of cholesta-5,7-dien-3-ol and lower proportions of cholesterol. Thus, females might base their mate choice on the males' quality as indicated by the composition of their chemical signals.

Animals↗

PubMed2005

Intersexual differences in chemical composition of precloacal gland secretions of the amphisbaenian Blanus cinereus.

Pheromonal communication seems to be especially important in amphisbaenians, a group of reptiles morphologically and functionally adapted to fossorial life. Both male and female amphisbaenians (Blanus cinereus) produce copious amounts of a secretion from the precloacal glands. Analysis by gas chromatography-mass spectrometry revealed that these secretions contain 29 major lipophilic compounds, including several steroids (mainly cholesterol and cholesteryl methyl ether), n-C9 to n-C18 carboxylic acids (more diverse in males), and methyl and long-chain (waxy)-type esters of carboxylic acids, along with squalene (mainly in males) and tocopherol (only in females). There were clear intersexual differences in the presence/absence of some compounds, such as some fatty acids, steroids, and tocopherol, and in the relative proportions of some shared compounds, such as squalene. These differences may explain how the sexes of this amphisbaenian discriminate one another based on scent alone. The abundance of steroids and waxy esters in secretions of both male and female amphisbaenians may be useful to scent mark underground tunnels to facilitate orientation by these organisms.

Animals↗

PubMed2005

Expression of CD45 and proliferative response to CD3 as suitable classification markers of patients with gastric adenocarcinoma.

25 patients with resectable gastric adenocarcinoma, subdivided according to the absence or presence of residual neoplasic disease (RND- or RND+, respectively), were studied. Cytofluorometric analysis and proliferative responses to mitogens was performed in peripheral blood mononuclear cells of patients. When compared to healthy subjects, the percentage of CD3-expressing cells was significantly reduced in both groups of patients studied (p < 0.0001 in all instances). However, when CD45 is considered instead of (CD3, its expression is found to be significantly reduced only in the RND+ patients (72% +/- 11), when compared with the control group (96 +/- 1%, p < 0.0001). Likewise, cells from these patients significantly less proliferated when stimulated with monoclonal antibodies to CD3 than control cells (18,920 +/- 6,019 cpm vs. 42,697 +/- 1,798 cpm, p = 0.0036); a difference not found if RND- patients (33,619 +/- 11,733 cpm) were considered. We propose that the low expression of CD45 and the poor response to CD3 are markers that are able to identify the subgroup of patients in whom the disease will tend to progress more rapidly. We also suggest the use of such markers as additional criteria for the classification of patients with gastric adenocarcinoma or to identify patients who require more aggressive therapeutic strategies.

Adenocarcinoma↗

PubMed2004

Thermal dependence of chemical assessment of predation risk affects the ability of wall lizards, Podarcis muralis, to avoid unsafe refuges.

Prey often respond to predators by increasing refuge use, but some refuges may expose prey to other types of predators. Because predators are not always visible inside refuges, their chemical stimuli may provide early warning of their presence. However, in ectotherms, chemosensory detection of predators may be thermally dependent. Lizards often hide in cold refuges, where their body temperature (Tb) may decrease, and this might affect their ability to detect chemicals of saurophagous snakes that ambush inside refuges. We examined the effects of Tb of wall lizards, Podarcis muralis, on their ability to detect chemicals of smooth snakes, Coronella austriaca. Differential tongue flick (TF) rates and behavioral patterns of lizards in response to scent of smooth snakes showed that lizards with optimal Tb discriminated and avoided the snake's scent, whereas lizards with suboptimal Tb did not. We also examined the importance of this effect on movement patterns and refuge use by lizards in terraria with safe (odorless) or unsafe refuges (snake-scented). While results of this experiment were variable, there was evidence of snake avoidance in that lizards at optimal Tb spent less time in snake-scented refuges relative to odorless refuges. Therefore, this study provides evidence that chemosensory discrimination of snake chemicals is thermally dependent, and, thus, suboptimal Tb impedes a lizard's ability to avoid snake-scented refuges.

Analysis of Variance↗

PubMed2004

Double gametocyte infections in apicomplexan parasites of birds and reptiles.

The simultaneous occurrence of male and female gametocytes inside a single host blood cell has been suggested to enhance apicomplexan transmission ["double gametocyte infection (DGI) hypothesis"]. We did a bibliographic search and a direct screen of blood smears from wild birds and reptiles to answer, for the first time, how common are these infections in the wild. Taking these two approaches together, we report here cases of DGIs in Plasmodium, Haemoproteus, Leucocytozoon and Hepatozoon, and cases of male-female DGIs in Haemoproteus of birds and reptiles and in Leucocytozoon of birds. Thus, we suggest that DGIs and male female DGIs are more widespread than previously thought, opening a new research avenue on apicomplexan transmission.

Animals↗

PubMed2004

Detection and discrimination of conspecific scents by the anguid slow-worm Anguis fragilis.

We tested the ability of male slow-worms, Anguis fragilis, a limbless anguid lizard with secretive, semifossorial habits, to detect chemical associated with conspecifics by using a T-maze in the laboratory. Male slow-worms discriminated conspecific male and female scent deposits. Males selected the arm with female scent, suggesting that scent deposits may be used to locate potential mates. Also, male slow-worms did not avoid the chemicals of other males, suggesting that they are not territorial. However, males discriminated their own scent from those of other males, and spent more time exploring the arm with other male scent, which suggests that scent marks may bear information that could be used in future intrasexual social contexts. We conclude that discrimination of conspecifics based on scents may be more widespread than previously expected among lizards inhabiting visually restricted environments.

Animals↗

PubMed2004

Iberian rock lizards (Lacerta monticola) assess short-term changes in predation risk level when deciding refuge use.

Prey might assess that risk level estimated in the first encounter with a predator was fixed in subsequent responses, whereas prey using flexible behavior would track short-term changes in risk. The authors examined, in the field, refuge use of Iberian rock lizards (Lacerta monticola) after simulated predator attacks and tested (a) how risk was assessed when multiple sources of risk were present simultaneously, (b) how short-term changes in risk level of successive attacks affected refuge use, and (c) whether the interval between attacks was important, insofar as attacks were considered to be coming from the same or different predators. Results suggest that lizards have a flexible estimate of risk that is based on multiple sources and flexibly dependent on previous estimates.

Animals↗

PubMed2003

Preventive effect of zaprinast and 3-isobutyl, 1-methylxanthine (phosphodiesterase inhibitors) on gastric injury induced by nonsteroidal antiinflammatory drugs in rats.

Cyclic GMP plays an important role in maintaining homeostasis in the gastric mucosa. NSAIDs damage the mucosa by mechanisms that may be mediated by alterations in the intragastric concentration of cyclic GMP. To test this hypothesis we studied the effects of the oral administration of acetylsalicylic acid (100, 300, and 500 mg/kg), piroxicam (5, 10, and 20 mg/kg) and sodium diclofenac (10, 25, 50, and 100 mg/kg), and of their interaction with zaprinast (5 mg/kg) and IBMX (10 mg/kg), on intragastric concentrations of cyclic GMP and the gastric erosive index in rats. All determinations were done 3 hr after the NSAID was given. All NSAIDs induced dose-dependent decreases in mucosal concentrations of cyclic GMP, which correlated inversely with the surface area showing mucosal injury. In contrast, cyclic GMP concentrations remained normal, and no intragastric damage was seen in rats given zaprinast (cyclic GMP-specific phosphodiesterase inhibitor) or IBMX (non-specific phosphodiesterase inhibitor) or in combination with NSAIDs. These findings are in line with the hypothesis that cyclic GMP is involved in the biochemical mechanisms of NSAID-induced gastric injury.

1-Methyl-3-isobutylxanthine↗

PubMedDate not supplied

Chemical compounds from femoral gland secretions of male Iberian rock lizards, Lacerta monticola cyreni.

In spite of the importance of chemoreception and chemical signals in the social organization of lizards, there are only a few studies examining the chemical composition of secretions of lizards used for scent marking. The secretion of the femoral glands of male Iberian rock lizards (Lacerta monticola cyreni) contains 44 lipophilic compounds, including several steroids (mainly cholesterol), and n-C6 to n-C22 carboxylic acids, and minor components such as esters of carboxylic acids, alcohols, squalene, and one lactone. These compounds were identified on the basis of mass spectra, obtained by GC-MS. Most lipids were detected in all individuals, although relative proportions of each chemical show a high interindividual variability. This variability might be related to the characteristics or physical and health condition of males and might be the basis of female choice based on chemical cues observed in this lizard species.

Animals↗

PubMedDate not supplied

Lipids in the femoral gland secretions of male Schreiber's green lizards, Lacerta schreiberi.

In spite of the importance of chemoreception and chemical signals in social organization of lizards, only a few studies have examined the chemical composition of secretions that lizards use for intraspecific communication. The secretion of the femoral glands of male Schreiber's green lizards (Lacerta schreiberi) contains 51 lipophilic compounds, including several steroids, a-tocopherol, n-C9 to n-C22 carboxylic acids and their esteres, and minor components such as alcohols between C12 and C24, two lactones, two ketones, and squalene. These compounds were identified on the basis of mass spectra, obtained by GC-MS. We compared these chemicals with those found in other lizard species, and discussed how environmental conditions could explain the differential presence of chemicals in different lizards. Particularly, the high abundance of a-tocopherol in this lizard is suggested to contribute to avoid oxidation of other lipids in secretions, increasing chemical stability of scent marks in the humid conditions of its habitat.

Animals↗