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Biomedical subjects

J Millán

Publications and source records attributed to J Millán.

At least 19 recordsLinked to original sources

Prevalence and intensity of blood and intestinal parasites in a field population of a Mediterranean lizard, Lacerta lepida.

We describe the blood and intestinal parasites in the Ocellated lizard, Lacerta lepida, examining the factors that determine the prevalence and intensity of infection of haemogregarines, and the prevalence of coccidia and nematodes. In relation to haemogregarines, no juveniles were detected as being infected, whereas 71.7 % of adults were infected. The prevalence of infection was positively related to the size of the adults. There were no differences between seasons or sexes in the prevalence or intensity of infection in adults. There were no significant differences in the prevalence of infection by nematodes between ages or sexes, nor in relation to the size of adult lizards, but adult lizards excreting coccidian oocysts tend to be smaller. During the mating period, reproductive activities lead to a decrease in the body condition. However, neither the intensity of haemogregarine's infection nor the prevalence of intestinal parasites was related to the lizards' body condition.

Animals↗

Descriptive study of an avian pox outbreak in wild red-legged partridges (Alectoris rufa) in Spain.

This study describes the dynamics and epidemiology of an outbreak of avian pox in free-living, red-legged partridges (Alectoris rufa) in southern Spain. Between March 2000 and January 2001, 115 free-living, red-legged partridges (70 juveniles, 45 adults) were captured and radio-tagged. This, together with the necropsy of 44 carcasses (10 juveniles, 34 adults) found in the study area, and the inspection of 108 shot birds (74 juveniles, 34 adults) after a hunting drive in October, permitted a close monitoring of the course of the disease. Forty-one per cent of radio-tagged juveniles but none of 45 radio-tagged adults showed pox-like lesions at the time of capture, recapture, or necropsy. At least 40% of the juveniles that survived into the hunting season, but only 2.9% of the adults inspected at the same time, showed lesions suggestive of infection with avian poxvirus. The survival of juveniles during the peak of the outbreak was much lower than that of the adults, but we found no significant differences between the survival probabilities of juvenile partridges with and without pox-like lesions. Nevertheless, some birds may have developed lesions after their capture. The occurrence and course of the disease in a managed area with intense predator control underlines the need for studies on the combined influence of diseases and predators on population dynamics. Also the need for early detection of diseases for the management of game species is emphasized.

Animals↗

Plasma chemistry reference values from captive red-legged partridges (Alectoris rufa).

1. Haematological and plasma biochemical parameters of 66 captive red-legged partridges (Alectoris rufa) of both sexes were analysed in order to determine reference values, taking sex and age into account. 2. There were no statistically significant differences in haematocrit, plasma glucose content or creatine kinase activity either with age or between sexes. 3. Plasma cholesterol concentrations showed differences between sexes, whereas the plasma concentrations of urea, uric acid and creatinine were significantly affected by age. 4. Plasma triglyceride and total protein concentrations were affected by both sex and age. 5. A peak at 6 months old in those parameters related to protein metabolism, such as urea, uric acid and creatinine may be related to the end of the growing period and the start of ovulation after moulting.

Aging↗

Salmonella isolates from wild birds and mammals in the Basque Country (Spain).

The authors investigated the prevalence of Salmonella spp. in 205 wild birds and mammals belonging to 45 species during the years 2001 and 2002 in the Basque Country (Spain). Salmonella was isolated from 16 (7.8%) animals. The prevalence was 8.5% (7/82) in birds, and 7.2% (9/123) in mammals. Nine serotypes, all of them belonging to the species Salmonella enterica, were identified: two isolates of Typhimurium (from 1/3 griffon vultures [Gyps fulvus], and 1/5 sparrowhawks [Accipiter nisus]); one of 6,14:z4, z23: (subsp. houtenae, 1/1 common kestrel [Falco tinnunculus]); one of Muenchen (1/1 captive Harris's hawk [Parabuteo unicinctus]); two of Enteritidis (1/5 tawny owls [Strix aluco], and 1/14 foxes [Vulpes vulpes]); one of Give, Newport and Umbilo and one untyped islolate (4/22 badgers [Meles meles]); two of Worthington and one of 38:IV:z35 (subsp. arizonae, 3/40 wild boars [Sus scrofa]); and three other untyped isolates (1/1 northern fulmar [Fulmarus glacialis], 1/11 buzzards [Buteo buteo], 1/4 genets [Genetta genetta]). Salmonella isolation was never associated with macroscopic or microscopic lesions. The results of this study confirm the importance of wildlife as a Salmonella reservoir and as a potential risk for humans and livestock.

Animals↗

First occurrence of Mesocestoides sp. in a bird, the red-legged partridge, Alectoris rufa, in Spain.

Larvae of Mesocestoides sp. were found in the celomic cavity of one red-legged partridge (Alectoris rufa) from Azuara (Aragón, north-eastern Spain). This is the first report of this larval cestode occurring in birds from Spain. None of the other 36 partridges from this area nor 150 partridges from other Spanish localities were affected. The red-legged partridge does not seem to be an important link in the Mesocestoides sp. life-cycle.

Animals↗

[Laryngeal chondro-radionecrosis].

Laryngeal chondroradionecrosis is a complication following radiotherapy for laryngeal tumours that may appear many years after the treatment. We present the case of a 78 year old man, that come to the Accident and Emergency department with a prelaryngeal mass and hemoptysis. He had been treated 17 years before with radiotherapy for a vocal cond carcinoma. Posteriorly the lesion did a cutaneous fistula with complete laryngeal exposition and torpid evolution. Post-radiotherapy necrosis in the larynx is a serious complication though not a common one. A tumour recurrence needs to be excluded and even in this case a total laryngectomy is mandatory as it will end in total loss of laryngeal function.

Aged↗

Do helminths increase the vulnerability of released pheasants to fox predation?

The success of ring-necked pheasant (Phasianus colchicus) restocking in Asturias, northern Spain was assessed, and the role of parasites and predators in the mortality of released birds was studied. The experimental release of 56 radio-tagged pheasants showed that 98% of birds died within 12 days. As soon as 72 h after release, 67.5% of males and 55.0% of females were found dead. Foxes (Vulpes vulpes) killed 63% of the birds. The survival of those birds killed by foxes was lower than for birds which died due to other causes, and pheasants depositing eggs of the nematode Eucoleus contortus (Creplin, 1839) survived less than those apparently non-parasitized. No impact of the parasite on the pheasants' condition was found, but foxes preyed upon parasitized birds more than expected by random. The results suggest that: (i) the current pheasant releases in this area are unsuccessful and need to be improved; (ii) this is mainly due to intense predation by red foxes; and (iii) parasites could have some influence on the predation of released birds by foxes. However, the way parasites affect pheasant vulnerability remains unclear.

Animal Husbandry↗

Pathology of avian pox in wild red-legged partridges (Alectoris rufa) in Spain.

The diagnosis and pathology of an avian pox outbreak in free-living red-legged partridges in Cádiz, Southern Spain, is described. Diagnosis of the disease was based on histopathology, ultrastructural examination of, and virus isolation from lesions of necropsied animals. Lesions were present mainly in juvenile partridges (41%), and were observed primarily on the dorsal part of the digits or on the hock joint. The lesions ranged from small wartlike nodules to large tumor-like lesions. The presence of acute lesions of any grade as opposed to absence of lesions or healed lesions adversely affected body condition of the partridges (P <.01). Further investigations on the epidemiology of the disease and on the relation of the isolated strains to other avian poxviruses are under way.

Animals↗

Segregation of co-stimulatory components into specific T cell surface lipid rafts.

The glycosylphosphatidylinositol (GPI)-anchored protein CD59 and the ganglioside GM1 are present on lipid rafts that can be isolated in a detergent-insoluble membrane (DIM) fraction. TCR engagement promotes integration of components of the TCR/CD3 signaling machinery into DIM. As DIM are isolated as a heterogeneous mixture of coalescent membranes, it is uncertain whether the cofractionation of GPI-anchored proteins and GM1 reflects the existence of an association between these molecules within the same lipid rafts in the cell. We have studied the surface distribution of the co-stimulatory CD59 and GM1 molecules and their role in the recruitment of components of the TCR signaling machinery in DIM. Although both CD59 and GM1 are present in rafts, these molecules occur in a steady state, mainly clustered in different membrane subdomains. Multimerization of either molecule did not induce cocapping or co-internalization of the other. Aggregation of GM1, CD59 or TCR/CD3 increased tyrosine phosphorylation but only in the latter case was a significant increase observed in both tyrosine phosphorylation and recruitment of elements of the signaling machinery in DIM. Our results show the existence of specific co-stimulatory membrane microdomains that require a direct TCR/CD3 engagement for efficient recruitment of signaling machinery into rafts.

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Marked differences in the splanchnometry of farm-bred and wild red-legged partridges (Alectoris rufa L.).

Relative weights of heart, spleen, pancreas, and liver and the relative lengths of the small intestine and the cecum were taken from 40 farm-bred and 43 wild juvenile red-legged partridges (Alectoris rufa Linnaeus) in central Spain. Expressed as a ratio to head and body length, farm-bred partridges had lighter hearts (17% lighter), spleens (78%), and livers (29%) and shorter small intestines (15%) and cecae (20%), than wild birds of the same age. When expressed as a ratio to body weight, farm-bred juvenile red-legged partridges had lighter hearts (12%) and livers (23%) and shorter small intestines (9%) and cecae (12%) than wild partridges. Those differences might have been produced by diet differences (such as fiber-poor, high-energy feeds used on farms) and may affect the survival of farm-bred partridges after release.

Animals↗

The role of lipid rafts in signalling and membrane trafficking in T lymphocytes.

Combinatorial association of different lipid species generates microheterogeneity in biological membranes. The association of glycosphingolipids with cholesterol forms membrane microdomains--lipid rafts--that are involved in specialised pathways of protein/lipid transport and signalling. Lipid rafts are normally dispersed in cellular membranes and appear to require specialised machinery to reorganise them to operate. Caveolin-1 and MAL are members of two different protein families involved in reorganisation of lipid rafts for signalling and/or intracellular transport in epithelial cells. T cell activation induces a rapid compartmentalisation of signalling machinery into reorganised rafts that are used as platforms for the assembly of the signalling complex. Costimulatory molecules participate in this process by providing signals that mobilise raft lipids and proteins, and remodel the cytoskeleton to the contact site. As in epithelial cells, rafts are used also as vesicular carriers for membrane trafficking in T lymphocytes. Furthermore, there are potential similarities between the specialised protein machinery underlying raft-mediated processes in T lymphocytes and polarised epithelial cells.

Animals↗

Red wine intake prevents nuclear factor-kappaB activation in peripheral blood mononuclear cells of healthy volunteers during postprandial lipemia.

BACKGROUND: Several epidemiological studies have demonstrated the beneficial effect of red wine intake in reducing total and cardiovascular mortality. This effect has been attributed in part to its antioxidant properties. Because the monocytes/macrophages and the nuclear transcription factor kappaB (NF-kappaB) are implicated in the pathogenesis of atherosclerotic lesions, we examined the effect of red wine intake on the activation of NF-kappaB in peripheral blood mononuclear cells. METHODS AND RESULTS: Sixteen healthy volunteers were studied 3 times each: after a moderate dose, a low dose, and no wine with a fat-enriched breakfast. Lipid profile and NF-kappaB activation (electrophoretic mobility shift assay) were examined in blood samples taken before and 3, 6, and 9 hours after wine intake. In addition, mononuclear cells were incubated with VLDL in the presence of some antioxidants (quercetin and alpha-tocopherol succinate) contained in red wine to study their effects on NF-kappaB activation. Subjects receiving a fat-enriched breakfast had increased NF-kappaB activation in peripheral blood mononuclear cells coinciding with the augmentation in total triglycerides and chylomicrons. Red wine intake prevented NF-kappaB activity even though it induced a certain increase in serum lipids, particularly VLDL, that did not increase after the fat ingestion alone. However, another form of alcohol intake (vodka) did not modify the NF-kappaB activation provided by postprandial lipemia. In cultured mononuclear cells, isolated human VLDL caused NF-kappaB activation in a time-dependent manner that did not occur in the presence of the red wine antioxidants quercetin and alpha-tocopherol. CONCLUSIONS: Our results provide a new potential mechanism to explain the beneficial effects of red wine intake in the reduction of cardiovascular mortality.

Adult↗

The MAL proteolipid is necessary for the overall apical delivery of membrane proteins in the polarized epithelial Madin-Darby canine kidney and fischer rat thyroid cell lines.

The MAL proteolipid has been recently demonstrated as being necessary for correct apical sorting of the transmembrane influenza virus hemagglutinin (HA) in Madin-Darby canine kidney (MDCK) cells. The fact that, in contrast to MDCK cells, Fischer rat thyroid (FRT) cells target the majority of glycosylphosphatidylinositol (GPI)-anchored proteins to the basolateral membrane provides us with the opportunity to determine the role of MAL in apical transport of membrane proteins under conditions in which the majority of GPI-anchored proteins are (MDCK cells) or are not (FRT cells) targeted to the apical surface. Using an antisense oligonucleotide-based strategy to deplete endogenous MAL, we have observed that correct transport of apical transmembrane proteins associated (HA) or not (exogenous neurotrophin receptor and endogenous dipeptidyl peptidase IV) with lipid rafts, as well as that of the bulk of endogenous apical membrane, takes place in FRT cells by a pathway that requires normal MAL levels. Even transport of placental alkaline phosphatase, a GPI-anchored protein that is targeted apically in FRT cells, was dependent on normal MAL levels. Similarly, in addition to the reported effect of MAL on HA transport, depletion of MAL in MDCK cells caused a dramatic reduction in the apical delivery of the GPI-anchored gD1-DAF protein, neurotrophin receptor, and the bulk of membrane proteins. These results suggest that MAL is necessary for the overall apical transport of membrane proteins in polarized MDCK and FRT cells.

Animals↗

Linear classification of low-resolution EEG patterns produced by imagined hand movements.

Electroencephalograph (EEG)-based brain-computer interfaces (BCI's) require on-line detection of mental states from spontaneous EEG signals. In this framework, surface Laplacian (SL) transformation of EEG signals has proved to improve the recognition scores of imagined motor activity. The results we obtained in the first year of an European project named adaptive brain interfaces (ABI) suggest that: 1) the detection of mental imagined activity can be obtained by using the signal space projection (SSP) method as a classifier and 2) a particular type of electrodes can be used in such a BCI device, reconciling the benefits of SL waveforms and the need for the use of few electrodes. Recognition of mental activity was attempted on both raw and SL-transformed EEG data from five healthy people performing two mental tasks, namely imagined right and left hand movements.

Adult↗

The MAL proteolipid is necessary for normal apical transport and accurate sorting of the influenza virus hemagglutinin in Madin-Darby canine kidney cells.

The MAL (MAL/VIP17) proteolipid is a nonglycosylated integral membrane protein expressed in a restricted pattern of cell types, including T lymphocytes, myelin-forming cells, and polarized epithelial cells. Transport of the influenza virus hemagglutinin (HA) to the apical surface of epithelial Madin-Darby canine kidney (MDCK) cells appears to be mediated by a pathway involving glycolipid- and cholesterol- enriched membranes (GEMs). In MDCK cells, MAL has been proposed previously as being an element of the protein machinery for the GEM-dependent apical transport pathway. Using an antisense oligonucleotide-based strategy and a newly generated monoclonal antibody to canine MAL, herein we have approached the effect of MAL depletion on HA transport in MDCK cells. We have found that MAL depletion diminishes the presence of HA in GEMs, reduces the rate of HA transport to the cell surface, inhibits the delivery of HA to the apical surface, and produces partial missorting of HA to the basolateral membrane. These effects were corrected by ectopic expression of MAL in MDCK cells whose endogenous MAL protein was depleted. Our results indicate that MAL is necessary for both normal apical transport and accurate sorting of HA.

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CD4 segregates into specific detergent-resistant T-cell membrane microdomains.

In T cells, glycolipids, glycoproteins attached to the membrane via a glycosylphosphatidylinositol (GPI) anchor, and Src-like tyrosine kinases are highly enriched in a membrane fraction resistant to solubilization by nonionic detergents. We have investigated the distribution of CD4 in T-cell membranes and found that approximately 10% of the CD4 co-receptor is associated with detergent-insoluble membrane microdomains, whilst the remaining 90% is in soluble membranes. Moreover, approximately 60% of the "insoluble CD4" is present in membrane microdomains containing GPI-anchored proteins and high glycolipid-dependent kinase activity, whereas the remaining 40% displays no association with GPI-anchored proteins and lacks glycolipid-associated kinase activity These results indicate that CD4 segregates at least into three different membrane microenvironments: 1) soluble membranes; 2) insoluble membrane microdomains containing GPI-anchored proteins; and 3) insoluble membrane microdomains devoid of GPI-anchored proteins. The level of CD4 in insoluble membranes was not modified upon triggering activation by T-cell receptor-crosslinking but detectable amounts of CD3 subunits were recruited into these specialized membranes under those conditions. The physical separation of CD4 into different membrane microenvironments raises the possibility of that some of the multiple functions of CD4 might segregate into distinct types of lipid microenvironment. The fact that components of T-cell receptor/CD3 complex were recruited into insoluble membranes upon stimulation is consistent with the CD4 present in this membrane fraction might participate in T-cell receptor-triggered activation events.

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