The organization of spines and filaments in whole worms and cytoskeletal fractions of adult Schistosoma mansoni was investigated. The ultrastructure of the spine revealed a closely packed filamentous organization of 3.5- to 5.6-nm elements and electron-lucent areas. Spines were surrounded at the base by electron-dense bodies and membrane invaginations, and covered at the tip by the syncytial surface membrane. Filaments, 7.5-11.1 nm in diameter, were closely associated with the base of the spines, between muscles, near mitochondria or nuclei, and in spaces of the subtegument. Cytoskeletal fractions prepared by homogenizing adults in Tris-HCl buffer, containing 0.6 M KCl and 1.0% Triton X-100, represented 19%-25% and 32%-38% of wet weight of males and females, respectively. The fractions contained nuclei, spines, 8 to 11 nm filaments, myofibrils, and granules. Vitellaria and egg shells were abundant in fractions from females. Six polypeptides with estimated molecular weights of 130, 96, 84, 78, 74 and 43 kdaltons were identified by sodium dodecyl sulfate-polyacrylamide gel electrophoresis as the major components of the cytoskeleton. Monoclonal antibody to chicken actin (MAA) was localized predominantly in surface spines and tubercles of adult schistosomes by the indirect immunofluorescence test, while immune serum from infected mice reacted less specifically with the tegument. A 43-kdalton polypeptide with electrophoretic mobility identical to that of vertebrate actin, identified in cytoskeletal and tegumental fractions of adult worms, reacted positively with MAA on immunoblotting.(ABSTRACT TRUNCATED AT 250 WORDS)

A system is described for the study of activation and motility of Ascaris spermatozoa in vitro. Activation was accomplished by addition of the sperm-activating substances (SAS), extracted from the male accessory gland, to cells incubated in phosphate-buffered saline (pH 7.4) at 37-39 degrees C under anaerobic conditions (95% N2, 5% CO2). Activation is characterized by a change from spherical to ameboid shape with coalescence of the refringent granules. The normal ameboid spermatozoa bear several stubby and needle-like filopodia at the lamellipodial margin. Within the lamellipodium are bundles of microfilament-like structures extending toward the pseudopodial membrane and concentrating within the needle-like filopodia. These filopodia exhibit a pendulous, sweeping motion with subsequent retraction and disappearence within the main lamellipodium. Membranes of the ameboid cells interact at the pseudopodial regions with partial fusion, as suggested by apparent membrane breakdown between interdigitating portions of the pseudopodia. Activation is complete in 5-15 min, is totally inhibited at 4 degrees C and/or by an atmospheric environment, but can be reinitiated by transfer to anaerobic conditions at 22-39 degrees C. Activation also requires favorable pH (6.8-8.7) and continual exposure to sufficiently high sodium concentrations (134-154 mM), i.e., lowering of sodium concentration to 10 mM causes irreversible inactivation. Sodium may be replaced by potassium or lithium but not by Tris or sucrose. Proteinases (10 microgram/ml) can act as activators even though SAS lack detectable proteolytic activity against azoalbumin, azocasein, TAME and BTEE and SAS activation was not inhibited by TLCK or soybean trypsin inhibitor.

Migration of neutrophils across epithelial or endothelial barriers in response to chemotactic stimuli occurs in inflammation and host defense. Leukotriene B4 (LTB4) may be synthesized by and certainly induces chemotaxis of neutrophils. To better understand the interaction between LTB4, neutrophils, and endothelium and epithelium, we compared the effects of LTB4 on human peripheral blood neutrophil migration through filters alone and on human umbilical vein endothelial (HUVE) cells and three different epithelial cell types, Madin-Darby canine kidney (MDCK) cells, human colon carcinoma (T84) cells, and rat type II alveolar cells, cultured on these filters. Significant LTB4-stimulated neutrophil migration occurred at the lowest (1 nM) dose and in the shortest period of time (15 min) across endothelial cells vs. all three epithelial cell types, and interestingly, vs. filters alone. Dose-response experiments (1-100 nM) indicated that at equimolar LTB4 concentrations neutrophil migration across endothelium was two- to threefold greater than that observed across filters alone and the three epithelial barriers. At higher LTB4 concentrations (100 nM), the degree of neutrophil migration through the three epithelial barriers was equivalent to that observed for filters alone. Overall, the data indicate that the various cellular barriers play an active role in inflammatory processes by regulating the transmigration of neutrophils in response to certain inflammatory chemotactic stimuli.

Stimulated neutrophil migration across lung endothelial and epithelial barriers is important in lung inflammatory processes. To better understand the interaction between chemoattractants, neutrophils, and endothelium and epithelium, we compared the ability of leukotriene B4 (LTB4), formylmethionylleucylphenylalanine (FMLP), and platelet-activating factor (PAF) to induce human neutrophil migration across 3-microns-pore filters alone and human umbilical vein endothelial (HUVE) cells and two different epithelial cell types, Madin-Darby canine kidney (MDCK) cells and human lung A549 cells, cultured in monolayers on these filters. LTB4, FMLP, and PAF induced neutrophil migration through naked filters, endothelial cells, and epithelial cells in a dose-related fashion. At optimal chemoattractant doses, LTB4, FMLP, and PAF induced relatively equivalent neutrophil migration through filters and endothelial and epithelial monolayers. However, the doses at which optimal neutrophil migration was observed to occur as well as the degree of neutrophil migration through the three barriers varied depending upon the chemoattractant. Based on dose-response experiments, the relative rank order of potency for the three chemoattractants was: LTB4 = FMLP greater than PAF for filter alone barrier; LTB4 greater than FMLP greater than PAF for HUVE cell barrier; and FMLP greater than LTB4 greater than PAF for MDCK and A549 epithelial cell barriers. Our data suggest that neutrophil chemotactic and subsequent lung inflammatory responses are interrelatedly influenced by both the quantity and type of chemoattractant present and the barrier through which the neutrophil must migrate.

With the introduction of mechanical circulatory support, mainly continuous-flow left ventricular assisted devices (CF-LVAD), prolonging survival in end-stage heart failure patients can be seen in a new light. We also anticipate its use as a definitive therapy to overcome the limited donor organ resources for cardiac transplant. However, LVADs also have undesirable device-related complications and questionable improvement in the quality of life. In this review, we searched published articles using PubMed and Google Scholar to identify the complications and outcome of post-LVAD patients from 2014 to 2019. The studies we used included all study design types and a wide range of demographic variables focusing on age, sex, choice of LVAD as a bridge to cardiac transplant, or definitive therapy. For patients with New York Heart Association (NYHA) Class III B or IV or heart failure with reduced ejection fraction (HFrEF) with maximal medication therapy, there is a significant increase in mean ejection fraction from 4% to 6%. For patients with drug-induced cardiac toxicity or other causes of cardiac toxicity, with no significant risk factors, the ejection fraction increased to nearly 50% within 10-25 days of LVAD usage. There is also a substantial improvement in the quality of life in this literature review comparing to the pre-LVAD stage, as long as complications are taken into account. Data is limited for making an accurate judgment on the quality of life and functional capacity of LVADs. We found that the use of LVADs is not fully cost-effective, but still less financially burdening than a cardiac transplant. Although data from worldwide is limited and restricted to studies having a range of one to two years of follow-up, we conclude that LVADs are promising in improving cardiac function and the best bridging therapy available for patients waiting on a transplant.