Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0038187 (starvation)
 24,951 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The author discusses the health status of 800 million persons who live in developing countries under conditions of absolute misery, and the 450 million on the brink of starvation, taking into account environmental factors which directly affect this situation of shortages, illness and death. Data are presented on diseases directly related to environmental conditions: 200 million people infested with schistosomes and 500 million at risk of infestation. In the case of Chagas' disease, 16 to 18 million are infected and 90 million at risk. The epidemiological situation regarding plague, the epidemiological risks of leptospirosis, the taeniasis-cysticercosis complex and other infectious and parasitic diseases are discussed. A description is given of the organisation and function of veterinary public health services, with comments on, and justification of the various activities which can be undertaken to prevent, reduce and even eradicate various diseases associated with poor hygienic conditions in the environment. Finally, proposals are made to revise the academic instruction of veterinarians. There is an urgent need to promote collaboration between institutes and between disciplines if the environment is to be protected and lives saved.
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PMID:[Protection of the environment and veterinary public health activities]. 152 17

Defaecation timing of the Triatominae vectors of Trypanosoma cruzi directly affects the transmission probability of Chagas disease to mammal hosts. Experimental studies with fifth instar nymphs of Triatoma infestans showed that defaecation time was negatively affected by blood meal size and positively affected by starvation period and bug initial weight. Since blood meal size and starvation period are both density-dependent, low density domestic populations of T. infestans would represent a higher transmission risk than high density populations. As low density populations could occur in recently reinfested houses after control using insecticide, vigilance activities should be reinforced to protect the human population at the highest risk of disease transmission.
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PMID:Density-dependent timing of defaecation by Triatoma infestans. 180 60

Labial salivary glands are found in the majority of insects. They are relatively large, extend back into the thorax, and in Rhodnius, they are cherry red in color due to a pigment derived from traces of hemoglobin absorbed form the gut. In most insects they are acinous shaped, with long excretion channels that present differentiated regions which from salivary reservoirs. The glands may be relatively simple or complexly branched and convoluted. In Rhodnius they are described as being unilobed with no traces of division. The main duct leaves the gland at its anterior extremity. The acini have different kinds of cells but all of them are seen as sources of secretion. Our material has a different shape due to the fact that the animals spent 20 days under starvation conditions. New data are also obtained through treatment with collagenase and HCl. The importance of the study of these glands lies in the fact that it will further understanding of the transmission of Chagas' disease.
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PMID:Scanning electron microscopy of the Rhodnius neglectus (Hemiptera) labial salivary glands after starvation. 825 Feb 70

In epimastigotes of Trypanosoma cruzi, the etiological agent of Chagas' disease, arginine kinase activity increased continuously during the exponential phase of growth. A correlation between growth rate, enzyme-specific activity and enzyme protein was observed. Arginine kinase-specific activity, expressed as a function of enzyme protein, remains roughly constant up to 18 days of culture. In the whole range of the culture time mRNA levels showed minor changes indicating that the enzyme activity is post-transcriptionally regulated. Arginine kinase could be proposed as a modulator of energetic reserves under starvation stress condition.
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PMID:Arginine kinase of the flagellate protozoa Trypanosoma cruzi. Regulation of its expression and catalytic activity. 1138 91

Data from the Chagas Disease Control Program indicate a growing domiciliary and peridomiciliary invasion of Triatoma rubrovaria in the State of Rio Grande do Sul, where it has become the most frequent triatomine species captured there since the control of T. infestans. Bionomic characteristics that could influence the vectorial capacity of T. rubrovaria as vector of Trypanosoma cruzi were evaluated: patterns of (i) feeding, (ii) defecation, and (iii) resistance to starvation, using insects fed on mice. Fifty three percent of the females showed a defecation pattern conducive to chagasic transmission, defecating either on or near the bite site. The averages of the resistance to starvation varied from 48.1 to 179 days, for the first and fifth nymphal stages, respectively. Our study shows that with respect to the patterns of feeding, defecation and resistance to fasting, T. rubrovaria presented similar rates to the ones observed for other effective vector species, such as T. infestans. Thus, based on our studies we conclude that T. rubrovaria has biological characteristics that can positively influence its capacity to become infected and transmit T. cruzi, and also to keep residual populations after chemical control interventions.
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PMID:Triatoma rubrovaria (Blanchard, 1843) (Hemiptera-Reduviidae-Triatominae) III: patterns of feeding, defecation and resistance to starvation. 1288 16

The present work examines the thermal preference of adult Rhodnius prolixus along a temperature gradient. The mean preferred temperature differed slightly between sexes: 25.0 degrees C for males versus 25.4 degrees C for females. This preference was not constant, but varied daily by about 0.2 degrees C for both sexes, and reached its highest value at the onset of the dark phase and was lowest during the light phase. A change in the preferred temperature with the level of starvation was also observed (about 1 degrees C lower after 20 days of starvation). Changes in environmental temperature strongly affected the rate of weight loss for both sexes. When insects were maintained for 20 days in a chamber at 32 degrees C, they lost significantly more weight than when kept at 24 degrees C; both water loss and nutrient conversion processes are involved. This increase in weight loss rate with increasing temperature would cause a higher biting rate and consequently higher probability of Chagas' disease transmission. Females oviposit across a range of temperatures from 22 to 33 degrees C with a peak at 25-26 degrees C. These results are compared with patterns of thermopreference in other species of triatomine, as related to differences in their distribution and tolerance to starvation.
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PMID:Temperature preference in Rhodnius prolixus, effects and possible consequences. 1473 30

We have recently reported that Trypanosoma cruzi infection protects cardiomyocytes against apoptosis induced by growth factor deprivation. Cruzipain, a major parasite antigen, reproduced this survival effect by a Bcl-2-dependent mechanism. In this study, we have investigated the molecular mechanisms of cruzipain-induced cardiomyocyte protection. Neonatal BALB/c mouse cardiac myocytes were cultured under minimum serum conditions in the presence of cruzipain or T. cruzi (Tulahuen strain). Some cultures were pretreated with the phosphatidylinositol 3-kinase (PI3K) inhibitor Ly294002 or specific inhibitors of the mitogen-activated protein kinase (MAPK) family members such as the mitogen-activated protein kinase kinase (MEK1) inhibitor PD098059, Jun N-terminal kinase (JNK) inhibitor SP600125, p38 MAPK inhibitor SB203580. Inhibition of PI3K and MEK1 but not JNK or p38 MAPK increased the apoptotic rate of cardiomyocytes treated with cruzipain. Phosphorylation of Akt, a major target of PI3K, and ERK1/2, MEK1-targets, was achieved at 15 min and 5 min, respectively. In parallel, these kinases were strongly phosphorylated by T. cruzi infection. In cultures treated with cruzipain, cleavage of caspase 3 was considerably diminished after serum starvation; Bcl-2 overexpression was inhibited by PD098059 but not by Ly294002, whereas Bad phosphorylation and Bcl-xL expression were increased and differentially modulated by both inhibitors. The results suggest that cruzipain exerts its anti-apoptotic property in cardiac myocytes at least by PI3K/Akt and MEK1/ERK1/2 signaling pathways. We further identified a differential modulation of Bcl-2 family members by these two signaling pathways.
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PMID:Different signaling pathways are involved in cardiomyocyte survival induced by a Trypanosoma cruzi glycoprotein. 1681 23

Autophagy is the major mechanism used by eukaryotic cells to degrade and recycle proteins and organelles. Bioinformatics analysis of the genome of the protozoan parasite Trypanosoma cruzi revealed the presence of all components of the Atg8 conjugation system, whereas Atg12, Atg5, and Atg10 as the major components of the Atg12 pathway could not be identified. The two TcATG4 (autophagin) homologs present in the genome were found to correctly process the two ATG8 homologs after the conserved Gly residue. Functional studies revealed that both ATG4 homologues but only one T. cruzi ATG8 homolog (TcATG8.1) complemented yeast deletion strains. During starvation of the parasite, TcAtg8.1, but not TcAtg8.2, was found by immunofluorescence to be located in autophagosome-like vesicles. This confirms its function as an Atg8/LC3 homolog and its potential to be used as an autophagosomal marker. Most importantly, autophagy is involved in differentiation between developmental stages of T. cruzi, a process that is essential for parasite maintenance and survival. These findings suggest that the autophagy pathway could represent a target for a novel chemotherapeutic strategy against Chagas disease.
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PMID:Autophagy is involved in nutritional stress response and differentiation in Trypanosoma cruzi. 1803 53

The genome of Trypanosoma cruzi was surveyed for autophagy-related genes. We have identified all the essential genes except for the Atg12 conjugation system and demonstrated functionality of the putative ATG4 and ATG8 homologs. TcAtg4.1 was primarily involved in the proteolytic processing of TcAtg8.1, the ATG8-homolog that was found to be localized to autophagosomal membranes during starvation. Autophagy was also found to be strongly upregulated during differentiation between developmental stages, a process that is essential for the propagation of the parasite. Based on our work, new strategies for treatment of Chagas disease, a chronic debilitating condition still without suitable chemotherapy, can be envisioned.
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PMID:Blocking autophagy to prevent parasite differentiation: a possible new strategy for fighting parasitic infections? 1821 33

The etiologic agent of Chagas disease, Trypanosoma cruzi, infects mammalian cells activating a signal transduction cascade that leads to the formation of its parasitophorous vacuole. Previous works have demonstrated the crucial role of lysosomes in the establishment of T. cruzi infection. In this work we have studied the possible relationship between this parasite and the host cell autophagy. We show, for the first time, that the vacuole containing T. cruzi (TcPV) is decorated by the host cell autophagic protein LC3. Furthermore, live cell imaging experiments indicate that autolysosomes are recruited to parasite entry sites. Interestingly, starvation or pharmacological induction of autophagy before infection significantly increased the number of infected cells whereas inhibitors of this pathway reduced the invasion. In addition, the absence of Atg5 or the reduced expression of Beclin 1 -- two proteins required at the initial steps of autophagosome formation -- limited parasite entry and reduced the association between TcPV and the classical lysosomal marker Lamp-1. These results indicate that mammalian autophagy is a key process that favors the colonization of T. cruzi in the host cell.
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PMID:The autophagic pathway is a key component in the lysosomal dependent entry of Trypanosoma cruzi into the host cell. 1911 81


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