Echocardiographic Assessment of the Pulmonary Venous Flow: An Indicator of Increased Pulmonary Flow in Congenital Cardiac Malformations

OBJECTIVE: To identify the left inferior pulmonary vein as an indirect marker of increased pulmonary flow in congenital heart diseases.METHODS: We carried out a prospective consecutive study on 40 patients divided into 2 groups as follows: G1 - 20 patients diagnosed with congenital heart disease and increased pulmonary flow; G2 (control group) - 20 patients who were either healthy or had congenital heart disease with decreased or normal pulmonary flow. We obtained the velocity-time integral of the left inferior pulmonary vein flow, excluding the "reverse A" wave, with pulsed Doppler echocardiography.RESULTS: In G1, 19 out of the 20 patients had well-identified dilation of the left inferior pulmonary vein. No G2 patient had dilation of the left inferior pulmonary vein. Dilation of the left inferior pulmonary vein in conditions of increased pulmonary flow had sensitivity of 95%, specificity of 100%, positive predictive value of 100%, and negative predictive value of 95% (1 false-negative case). The integral of time and velocity of the pulmonary venous flow obtained with pulsed Doppler echocardiography was greater in the G1 patients (G1=25.0±4.6 cm versus G2=14.8±2.1 cm, p=0.0001).CONCLUSION: The identification of dilation of the left inferior pulmonary vein suggests the presence of congenital heart disease with increased pulmonary flow. This may be used as an indirect sign of increased flow, mainly in malformations of difficult diagnosis, such as atrial septal defects of the venous sinus or coronary sinus type.

Effects of high glucose concentrations on the endothelial function of the renal microcirculation of rabbits

OBJECTIVE: To assess the acute effects of high glucose concentrations on vascular reactivity in the isolated non diabetic rabbit kidney. METHODS: Rabbits were anaesthetized for isolation of the kidneys. Renal arteries and veins were cannulated for perfusion with Krebs-Henselleit solution and measurement of perfusion pressure. After 3 hours of perfusion with glucose 5,5 mM (control ) and 15 mM, the circulation was submitted to sub maximal precontraction (80% of maximal response) trough continuous infusion of noradrenaline 10 mM. Vascular reactivity was then assessed trough dose-responses curves with endothelium-dependent (acetylcholine) and independent (sodium nitroprusside) vasodilators. The influence of hyperosmolarity was analyzed with perfusion with mannitol 15mM. RESULTS: A significant reduction in the endothelium-dependent vasodilation in glucose 15mM group was observed compared to that in control, but there was no difference in endothelium-independent vasodilation. After perfusion with mannitol 15 mM, a less expressive reduction in endothelium-dependent vasodilation was observed, only reaching significance in regard to the greatest dose of acetylcholine. CONCLUSION: High levels of glucose similar to those found in diabetic patients in the postprandial period can cause significant acute changes in renal vascular reactivity rabbits. In diabetic patients these effects may also occur and contribute to diabetes vascular disease.

Development of Anatomophysiologic Knowledge Regarding the Cardiovascular System: From Egyptians to Harvey

Our knowledge regarding the anatomophysiology of the cardiovascular system (CVS) has progressed since the fourth millennium BC. In Egypt (3500 BC), it was believed that a set of channels are interconnected to the heart, transporting air, urine, air, blood, and the soul. One thousand years later, the heart was established as the center of the CVS by the Hippocratic Corpus in the medical school of Kos, and some of the CVS anatomical characteristics were defined. The CVS was known to transport blood via the right ventricle through veins and the pneuma via the left ventricle through arteries. Two hundred years later, in Alexandria, following the development of human anatomical dissection, Herophilus discovered that arteries were 6 times thicker than veins, and Erasistratus described the semilunar valves, emphasizing that arteries were filled with blood when ventricles were empty. Further, 200 years later, Galen demonstrated that arteries contained blood and not air. With the decline of the Roman Empire, Greco-Roman medical knowledge about the CVS was preserved in Persia, and later in Islam where, Ibn Nafis inaccurately described pulmonary circulation. The resurgence of dissection of the human body in Europe in the 14th century was associated with the revival of the knowledge pertaining to the CVS. The main findings were the description of pulmonary circulation by Servetus, the anatomical discoveries of Vesalius, the demonstration of pulmonary circulation by Colombo, and the discovery of valves in veins by Fabricius. Following these developments, Harvey described blood circulation.

Estudos sobre a alimentação mineral do cafeeiro: VI Efeitos das deficiências de micronutrientes em Coffea arabica L. var. Mundo Novo cultivado em solução nutritiva

Young coffee plants (Coffea arabica L., var. Mundo Novo) were grown in nutrient solution purified from micronutrients contaminants by the method of MUNNS & JOHNSON (1960). All plants, except those in the control treatment, wer given all macronutrients and all micronutrients except one which was omitted in order to induce its shortage. Symptoms of deficiency were obtained for all known micronutrients but chlorine. Measurements, observations and chemical analysis of leaves allowed the following main conclusions to be drawn. 1. The relative influence of micronutrients in growth-measured by the fresh weight of the entire plant - was as follows: -Fe -Zn -Cu -Mo -Mn complete = -B = -CI. that is: the omission of iron from the nutrient solution caused the severest reduction in growth; lack of B and Cl had no effect. 2. Symptoms of deficiency of B, Fe, Mn, and Zn were found to be in good agreement with those in the literature. Effects of Cu and Mo shortage, however, had not been described so far: In the case of the Cu-deficient plants, the younger leaves were distorted, having an "S" shape, due probably to lack of growth of the veins; they lost their green color and developed rather large, necrotic patches near the margins. When molybdenum was omitted from the nutrient solution yellow spots develop near the margen of subterminal (fully mature) leaves; they became necrotic; there was a characteristic downward curling of the leaf blade along the mid rib so that the opposite edges touched each other underneath. 3. The levels of micronutrients found in normal and deficient leaves are given in Table 4. It is hoped that those values will serve as a basis of judgement of micronutrient contents found in leaves of field grown plants.

Estudos sobre thrombose cardiaca e endocardite parietal de origem não valvular

1.-Since the parietal endocarditis represents a chapter generally neglected, owing to the relative lack of cases, and somewhat confused because there various terms have been applied to a very same morbid condition, it justifies the work which previously we tried to accomplish, of nosographic classification. Taking into account the functional disturbances and the anatomical changes, all cases of parietal endocarditis referred to in the litterature were distributed by the following groups: A-Group-Valvulo-parietal endocarditis. 1st . type-Valvulo-parietal endocarditis per continuum. 2nd. type-Metastatic valvulo-parietal endocarditis. 3rd. type-Valvulo-parietal endocarditis of the mitral stenosis. B-Group-Genuine parietal endocarditis. a) with primary lesions in the myocardium. b) with primary lesions in the endocardium. 4th type-Fibrous chronic parietal endocarditis (B A Ü M L E R), « endocarditis parietalis simplex». 5th type-Septic acute parietal endocarditis (LESCHKE), «endocarditis parietalis septica». 6th type-Subacute parietal endocarditis (MAGARINOS TORRES), «endocarditis muralis lenta». 2.-Studying a group of 14 cases of fibrous endomyocarditis with formation of thrombi, and carrying together pathological and bacteriological examinations it has been found that some of such cases represent an infectious parietal endocarditis, sometimes post-puerperal, of subacute or slow course, the endocardic vegetations being contamined by pathogenic microörganisms of which the most frequent is the Diplococcus pneumoniae, in most cases of attenuated virulence. Along with the infectious parietal endocarditis, there occur arterial and venous thromboses (abdominal aorta, common illiac and femural arteries and external jugular veins). The case 5,120 is a typical one of this condition which we name subacute parietal endocarditis (endocarditis parietalis s. muralis lenta). 3.-The endocarditis muralis lenta encloses an affection reputed to be of rare occurrence, the «myocardite subaigüe primitive», of which JOSSERAND and GALLAVARDIN published in 1901 the first cases, and ROQUE and LEVY, another, in 1914. The «myocardite subaigüe primitive» was, wrongly, in our opinion, included by WALZER in the syndrome of myocardia of LAUBRY and WALZER, considering that, in the refered cases of JOSSERAND and GALLAVARDIN and in that of ROQUE and LEVY, there are described rather considerable inflammatory changes in the myocardium and endocardium. The designation «myocardia» was however especially created by LAUBRY and WALZER for the cases of heart failure in which the most careful aetiologic inquiries and the most minucious clinical examination were unable to explain, and in which, yet, the post-mortem examination did not reveal any anatomical change at all, it being forcible to admit, then, a primary functional change of the cardiac muscle fibre. This special cardiac condition is thoroughly exemplified in the observation that WALZER reproduces on pages 1 to 7 of his book. 4.-The clinical picture of the subacute parietal endocarditis is that of heart failure with oedemas, effusion in the serous cavities and passive chronic congestion of the lungs, liver, kideys and spleen associated, to that of an infectious disease of subacute course. The fever is rather transient oscillating around 99.5 F., being intersected with apyretic periods of irregular duration; it is not dependent on any evident extracardiac septic infection. In other cases the fever is slight, particularly in the final stage of the disease, when the heart failure is well established. The rule is to observe then, hypothermy. The cardiac-vascular signs consist of enlargement of the cardiac dullness, smoothing of the cardiac sounds, absence of organic murmurs and accentuated and persistent tachycardia up to a certain point independent of fever. The galloprhythm is present, in most cases. The signs of the pulmonary infarct are rather expressed by the aspect of the sputum, which is foamy and blood-streaked than by the classic signs. Cerebral embolism was a terminal accident on various cases. Yet, in some of them, along with the signs of septicemia and of cardiac insufficiency, occurred vascular, arterial (abdominal aorta, common illiac and femurals arteries) and venous (extern jugular veins) thromboses. 5. The autopsy revealed an inflammatory process located on the parietal endocardium, accompanied by abundant formation of ancient and recent thrombi, being the apex of the left ventricle, the junction of the anterior wall of the same ventricle, with the interventricular septum, and the right auricular appendage, the usual seats of the inflammatory changes. The region of the left branch of HIS’ bundle is spared. The other changes found consist of fibrosis of the myocardium (healed infarcts and circumscribed interstitial myocarditis), of recent visceral infarcts chiefly in lungs, spleen and brain, of recent or old infarcts in the kidneys (embolic nephrocirrhosis) and in the spleen, and of vascular thromboses (abdominal aorta, common illiacs and femurals arteries and external jugular veins), aside from hydrothorax, hydroperitoneum, cutaneous oedema, chronic passive congestion of the liver, lungs, spleen and kidneys and slight ictericia. 6. In the subacute parietal endocarditis the primary lesions sometimes locate themselves at the myocardium, depending on the ischemic necrosis associated to the arteriosclerosis of the coronariae arteries, or on an specific myocarditis. Other times, the absence of these conditions is suggestive of a primary attack to the parietal endocardium which is then the primary seat of the lesions. It matters little whatever may be the initial pathogenic mechanism; once injured the parietal endocardium and there being settled the infectious injury, the endocarditis develops with peculiar clinical and anatomical characters of remarkable uniformity, constituting an anatomo-clinical syndrome. 7.-The histologic sections show that recent lesions…

Prevalence and clinical importance of mesenteric venous thrombosis in the swiss inflammatory bowel disease cohort.

OBJECTIVE. The purpose of this study was to evaluate the prevalence of mesenteric venous thrombosis (MVT) in the Swiss Inflammatory Bowel Disease Cohort Study and to correlate MVT with clinical outcome. MATERIALS AND METHODS. Abdominal portal phase CT was used to examine patients with inflammatory bowel disease (IBD). Two experienced abdominal radiologists retrospectively analyzed the images, focusing on the superior and inferior mesenteric vein branches and looking for signs of acute or chronic thrombosis. The location of abnormalities was registered. The presence of MVT was correlated with IBD-related radiologic signs and complications. RESULTS. The cases of 160 patients with IBD (89 women, 71 men; Crohn disease [CD], 121 patients; ulcerative colitis [UC], 39 patients; median age at diagnosis, 27 years for patients with CD, 32 years for patients with UC) were analyzed. MVT was detected in 43 patients with IBD (26.8%). One of these patients had acute MVT; 38, chronic MVT; and four, both. The prevalence of MVT did not differ between CD (35/121 [28.9%]) and UC (8/39 [20.5%]) (p = 0.303). The location of thrombosis was different between CD and UC (CD, jejunal or ileal veins only [p = 0.005]; UC, rectocolic veins only [p = 0.001]). Almost all (41/43) cases of thrombosis were peripheral. MVT in CD patients was more frequently associated with bowel wall thickening (p = 0.013), mesenteric fat hypertrophy (p = 0.005), ascites (p = 0.002), and mesenteric lymph node enlargement (p = 0.036) and was associated with higher rate of bowel stenosis (p < 0.001) and more intestinal IBD-related surgery (p = 0.016) in the outcome. Statistical analyses for patients with UC were not relevant because of the limited population (n = 8). CONCLUSION. MVT is frequently found in patients with IBD. Among patients with CD, MVT is associated with bowel stenosis and CD-related intestinal surgery.

Extracorporeal membrane oxygenation support after heart explantation: a proposal on how to deal with hyperacute rejection of heart transplant

Purpose: In extreme situations, such as hyperacute rejection of heart transplant or major bleeding per-operating complications, an urgent heart explantation might be the only means of survival. The aim of this experimental study was to improve the surgical technique and the hemodynamics of an Extracorporeal Membrane Oxygenation (ECMO) support through a peripheral vascular access in an acardia model. Methods: An ECMO support was established in 7 bovine experiments (59±6.1 kg) by the transjugular insertion to the caval axis of a self-expanded cannula, with return through a carotid artery. After baseline measurements of pump flow and arterial and central venous pressure, ventricular fibrillation was induced (B), the great arteries were clamped, the heart was excised and right and left atria remnants, containing the pulmonary veins, were sutured together leaving an atrial septal defect (ASD) over the cannula in the caval axis. Measurements were taken with the pulmonary artery (PA) clamped (C) and anastomosed with the caval axis (D). Regular arterial and central venous blood gases tests were performed. The ANOVA test for repeated measures was used to test the null hypothesis and a Bonferroni t method for assessing the significance in the between groups pairwise comparison of mean pump flow. Results: Initial pump flow (A) was 4.3±0.6 L/min dropping to 2.8±0.7 L/min (P B-A= 0.003) 10 minutes after induction of ventricular fibrillation (B). After cardiectomy, with the pulmonary artery clamped (C) it augmented not significantly to 3.5±0.8 L/min (P C-B= 0.33, P C-A= 0.029). Finally, PA anastomosis to the caval axis was followed by an almost to baseline pump flow augmentation (4.1±0.7 L/min, P D-B= 0.009, P D-C= 0.006, P D-A= 0.597), permitting a full ECMO support in acardia by a peripheral vascular access. Conclusions: ECMO support in acardia is feasible, providing new opportunities in situations where heart must urgently be explanted, as in hyperacute rejection of heart transplant. Adequate drainage of pulmonary circulation is pivotal in order to avoid pulmonary congestion and loss of volume from the normal right to left shunt of bronchial vessels. Furthermore, the PA anastomosis to the caval axis not only improves pump flow but it also permits an ECMO support by a peripheral vascular access and the closure of the chest.

Pkd1 Regulates Lymphatic Vascular Morphogenesis during Development.

Lymphatic vessels arise during development through sprouting of precursor cells from veins, which is regulated by known signaling and transcriptional mechanisms. The ongoing elaboration of vessels to form a network is less well understood. This involves cell polarization, coordinated migration, adhesion, mixing, regression, and shape rearrangements. We identified a zebrafish mutant, lymphatic and cardiac defects 1 (lyc1), with reduced lymphatic vessel development. A mutation in polycystic kidney disease 1a was responsible for the phenotype. PKD1 is the most frequently mutated gene in autosomal dominant polycystic kidney disease (ADPKD). Initial lymphatic precursor sprouting is normal in lyc1 mutants, but ongoing migration fails. Loss of Pkd1 in mice has no effect on precursor sprouting but leads to failed morphogenesis of the subcutaneous lymphatic network. Individual lymphatic endothelial cells display defective polarity, elongation, and adherens junctions. This work identifies a highly selective and unexpected role for Pkd1 in lymphatic vessel morphogenesis during development.

An adapted model of ex vivo vein perfusion: the key to understand vessel wall remodeling

Objective: Saphenous vein graft bypass remains the salvage option when¦endovascular procedure has failed or was contraindicated due to extensive¦occlusive lesions. However, pathological wall remodeling leading leading to¦graft failure is one of the most limiting factors of this therapy. Therefore, the¦understanding of this remodeling process of human vein is essential to the design¦of future effective therapeutics and it requires an adapted model of ex-vivo vein¦perfusion.¦Methods: We have developed an ex vivo vein support system (EVVSS), which¦uses standardized and controlled hemodynamic parameters for the pulsatile¦perfusion of saphenous vein segments. The morphological and molecular¦parameters involved in the remodeling process under an arterial shear stress¦associated to low (7 mm Hg) or high (70 mm Hg) pressure conditions can be¦analyzed.¦Results: Histomorphometric analysis showed that the vein segments perfused¦during 7 days under high pressure undergo a significant neointima development¦compared to veins exposed to low pressure conditions. The application of an¦arterial shear stress in the vein under low pressure induced an elevation of the¦MMP-2 and MMP-9 expression, activity and transcription. The application of¦higher pressure is associated to increased MMP2 expression and transcription¦and MMP9 transcription. TIMP1 expression and transcription were initiated by¦the application of an arterial shear stress but not modified by the modification¦of the pressure. However, TIMP2 expression was increased under high¦pressure conditions but its transcription was inhibited by arterial shear stress,¦independently of the pressure. The values of transcription and expression of¦PAI-1 were not modified by high pressure. Eph-B4 transcription and expression¦were significantly decreased under arterial shear stress.¦Conclusion: These data show that our EVVSS is a valuable setting to study¦ex vivo remodeling of human saphenous veins submitted to arterial conditions.¦The intimal hyperplasia as well as MMP 2, 9 and TIMP 2 seem to be influenced¦by the pressure.

Shallow-level migmatization of gabbros in a metamorphic contact aureole, Fuerteventura Basal Complex, Canary Islands

Migmatization of gabbroic rocks at 2-3 kbar has occurred in the metamorphic contact aureole of a mafic pluton in the Fuerteventura Basal Complex (Canary Island;). Migmatites are characterized by a dense network: of closely spaced millimetre-wide leucocratic veins with perfectly preserved igneous textures. They are all relatively enriched in Al, Na I: Sr Ba, Nb, Y and the rare earth elements compared with the unaffected country rock beyond the aureole. Migmatization under such low-pressure conditions war possible because of the unusual tectonic and magmatic contact in which ii occurred. Multiple basic intrusions associated with extrusive volcanic activity created high heat flow in a small area. Alkaline and metasomatized rocks present in the country rock of the intruding pluton were leached by high-temperature fluids during contact metamorphism. These enriched fluids then favoured partial melting of the host gabbroic rocks, and contaminated both the leucosomes and melanosomes. A transpressive tectonic setting at the time of intrusion created shearing along the contact between the intrusion and its host rock. This shearing enhanced circulation of the fluids and allowed segregation of the nea-formed melts from their restite by opening tension veins into which the melts migrated. Depending on the relative timing of melt segregation and recrystallization leucosomes range in composition from a 40-60% mixture of clinopyroxene (+/- amphibole) and plagioclase to almost pure feldspathic veins. Comparable occurrences of gabbros migmatized at low pressure are expected only at a snail scale in localized areas of high heat flow in the presence of fluids, such as in. mid-ocean ridges or ocean-islands.

Autoradiographic analysis of Schistosoma mansoni migration in the NZ rabbit

The migration of larval Schistosoma mansoni was tracked by means of autoradiographic analysis in naive rabbits percutaneously exposed to L-(**75 Se) selenomethionine-labeled cercariae on serial intervals of 1, 2, 4, 6, 8, 10, 15, 20, 25, 30, 40 and 50 days post-infection. Autoradiographic foci were detected from the 1st day in the skin, up to the 15th day in the liver. Adult and mature worms were recovered either paired or not 60 days after infection, by perfusion of hepatic and mesenteric veins. Morphometric analysis under optical microscopy, showed that worms were within regular dimention limits as compared to adult worms harboured by other host species. These observations extend previous informations on the S. mansoni-rabbit association and clearly demonstrate the post-liver phase of S.mansoni life-cycle in this host.

Permian-polysulphide-siderite-barite-haematite deposit Rude in Samoborska Gora Mts., Zagorje-Mid-Transdanubian zone of the Inner Dinarides

Samoborska Gora Mts. is situated within the westernmost part of the Zagorje-Mid-Transdanubian zone of the Internal Dinarides. The Samoborska Gora Mts. predominantly consists of Permian unmetamorphosed siliciclastic sediments and evaporites, overlain by Lower Triassic sediments. Rude mineralisation is hosted by Permian siliciclastic sediments, below gypsum and anhydrite strata. The central part of the deposit consists of a 1.5 km long stratabound mineralisation, grading laterally into ferruginous sandstone and protruding vertically into a gypsum-anhydrite layer. Siderite-polysulphide-barite-quartz veins are located below the stratabound mineralisation. The stratiform part of the deposit is situated above the stratabound and consists of haematite layer with barite concretions and veinlets. Late stage galena-barite veins overprint earlier types of mineralisation. The Rude ore deposit was generated by predominantly NaCl +/- CaCl(2)-H(2)O solutions. Detrital quartz from stratiform mineralisation contains fluid inclusions with salinities between 7 and 11 wt. % NaCl equ., homogenizing between 150 degrees C to 230 degrees C. Stratabound/siderite-polysulphide-barite-quartz vein type mineralisation was derived from solutions with salinities between 5 and 19 wt. % NaCl equ., homogenizing between 60 degrees C and 160 degrees C, while late stage galenabarite veins were precipitated from solutions with salinities between 11 and 16 wt. % NaCl equ., homogenizing between 100 degrees C to 140 degrees C. Fluid inclusion bulk leachate chemistry recorded Na(+)> Mg(2+)>K(+)>Ca(2+)>Li(+) and Cl-> SO(4)(2-) ions. Sulphur isotope composition of barites and overlying gypsum stems from Permian seawater sulphate, supported by increased Br(-) content, which follows successively the seawater evaporation line. The sulphur isotopic composition of sulphides varies between -0.2 and + 12.5 parts per thousand , as a result of thermal reduction of Permian marine sulphate. Ore-forming fluids were produced by hydrothermal convective cells (reflux brine model), and were derived primarily from Permian seawater, modified by evaporation and interaction with Permian sedimentary rocks. Rude deposits in Samoborska Gora Mts. may be declared as a prototype of the Permian siderite-polysulphide-barite deposits (products of rifting along the passive Gondwana margin), in the Inner Dinarides, and their equivalents extending northeastward into the Zagorje-Mid-Transdanubian Zone and the Gemerides, and southeastward to the Hellenide-Albanides.

Prevalence and clinical importance of mesenteric venous thrombosis in the Swiss Inflammatory Bowel Disease Cohort

OBJECTIVE: The purpose of this study was to evaluate the prevalence of mesenteric venous thrombosis (MVT) in the Swiss Inflammatory Bowel Disease Cohort Study and to correlate MVT with clinical outcome. MATERIALS AND METHODS: Abdominal portal phase CT was used to examine patients with inflammatory bowel disease (IBD). Two experienced abdominal radiologists retrospectively analyzed the images, focusing on the superior and inferior mesenteric vein branches and looking for signs of acute or chronic thrombosis. The location of abnormalities was registered. The presence of MVT was correlated with IBD-related radiologic signs and complications. RESULTS: The cases of 160 patients with IBD (89 women, 71 men; Crohn disease [CD], 121 patients; ulcerative colitis [UC], 39 patients; median age at diagnosis, 27 years for patients with CD, 32 years for patients with UC) were analyzed. MVT was detected in 43 patients with IBD (26.8%). One of these patients had acute MVT; 38, chronic MVT; and four, both. The prevalence of MVT did not differ between CD (35/121 [28.9%]) and UC (8/39 [20.5%]) (p = 0.303). The location of thrombosis was different between CD and UC (CD, jejunal or ileal veins only [p = 0.005]; UC, rectocolic veins only [p = 0.001]). Almost all (41/43) cases of thrombosis were peripheral. MVT in CD patients was more frequently associated with bowel wall thickening (p = 0.013), mesenteric fat hypertrophy (p = 0.005), ascites (p = 0.002), and mesenteric lymph node enlargement (p = 0.036) and was associated with higher rate of bowel stenosis (p < 0.001) and more intestinal IBD-related surgery (p = 0.016) in the outcome. Statistical analyses for patients with UC were not relevant because of the limited population (n = 8). CONCLUSION: MVT is frequently found in patients with IBD. Among patients with CD, MVT is associated with bowel stenosis and CD-related intestinal surgery.

Natural infection of wild rodents by Schistosoma mansoni parasitological aspects

The evaluation of the role of rodents as natural hosts of Schistosoma mansoni was studied at the Pamparrão Valley, Sumidouro, RJ, with monthly captures and examination of the animals. Twenty-three Nectomys squamipes and 9 Akodom arviculoides with a shistosomal infection rate of 56.5% and 22.2% respectively eliminated a great majority of viable eggs. With a strain isolated from one of the naturally infected N. squamipes, we infected 75% of simpatric Biomphalaria glabrata and 100% of albino Mus musculus mice. The adult worms, isolated from N. squamipes after perfusion were located mainly in the liver (91.5%) and the mesenteric veins (8.5%). The male/female proportion was 2:1. The eggs were distributed on small intestine segments (proximal, medial and distal portions) and the large intestine without any significant differences in egg concentration of these segments. In A. arviculoides, the few eggs eliminated by the stools were viable and there was litlle egg retention on intestinal segments. Considering the ease to complete S. mansoni biological cycle in the Nectomys/Biomphalaria/Nectomys system under laboratory conditions, probably the same is likely to occur in natural conditions. In support to this hypotesis there are also the facts that human mansonic shistosomiasis has a very low prevalence in Sumidouro and endemicity among the rodents has not changed even after repetead treatments of the local patients. Based on our experiments, we conclude that N. squamipes has become a natural host of S. mansoni and possibly may participate in keeping the cycle of schistosomiasis transmission at Pamparrão Valley.