Hepatic Disease with Portal Hypertension and Acute Juvenile Paracoccidioidomycosis: A Report of Two Cases and Literature Review

Paracoccidioidomycosis (PCM) is a neglected systemic mycosis endemic to Latin America caused by dimorphic fungi of the genus Paracoccidioides. The acute juvenile PCM is a severe type of presentation that usually affects young vulnerable patients and rarely progresses to portal hypertension. Here, two cases of liver disease and portal hypertension as complications of acute juvenile PCM are reported. Diagnosis of PCM was performed by isolation of the fungus and molecular identification of the strains provided through partial sequencing of two protein encoding genes, arf and gp43. Genotypic analysis revealed that Paracoccidioides brasiliensis S1 was the phylogenic species involved in both cases. Patients presented a good clinical response to amphotericin B and sulfamethoxazole–trimethoprim. These results highlight the importance of the interdisciplinary approach in patients with severe forms of PCM to avoid and treat complications, and the necessity of further investigations focusing on host-pathogen interaction in order to explain the broad clinical spectrum in PCM as well as the severity and poor outcome in some clinical cases.     

A new multigene family encoding calcium-dependent calmodulin-binding membrane proteins of Paramecium tetraurelia

Ca2+/calmodulin (CaM) regulates various physiological processes in a wide variety of organisms, metazoa and protists alike. To better understand Ca2+/CaM-dependent processes, particularly those with membrane-associated components, we studied Ca2+/CaM-binding membrane proteins in Paramecium tetraurelia, a unicellular model system. A CaM-binding protein, PCM1 (Paramecium CaM-binding membrane-bound protein), from a detergent-solubilized ciliary membrane fraction was identified and purified through Ca2+-dependent CaM-affinity chromatography. PCM1 has an apparent molecular mass of approx. 65kDa. It binds radiolabeled CaM in blot overlay assays and binds to CaM-affinity columns, both only in the presence of 10 microM or higher Ca2+. Three peptide sequences from PCM1 were obtained, and polymerase chain reaction (PCR) and Southern hybridization experiments were designed accordingly, leading to a partial cDNA clone for PCM1 and the discovery of three homologs: PCM2, PCM3 and PCM4. Amino acid sequences predicted by the full-length coding sequence for PCM3 and partial genes for PCM1, PCM2 and PCM4 are very similar (approx. 85% amino-acid identities). Their sequences indicate that they are hitherto novel proteins with beta/gamma-crystallin domains, cysteine-rich regions and potential CaM-binding domains. These protein motifs are suggested to mediate protein-protein interaction important for Ca2+/CaM signal transduction event(s) through the PCM family of proteins.     

Purification and characterization of protein carboxyl methyltransferase from Torpedo ocellata electric organ

Posttranslational modification of proteins by the enzyme protein carboxyl methyltransferase (PCM) has been associated with a variety of cellular functions. A prerequisite for the understanding of cellular mechanisms associated with PCM is the characterization of purified PCMs from different tissues. We describe here the purification and characterization of PCM from the electric organ of Torpedo ocellata. The enzyme was purified to homogeneity by ion-exchange chromatography and ammonium sulfate precipitation, followed by chromatography on Sephadex G-100 and hydroxylapatite columns. When visualized by silver staining, the 700-fold-purified PCM exhibited a single band on sodium dodecyl sulfate-polyacrylamide gels, corresponding to a polypeptide of Mr 29,000. The molecular weight of the nondenatured enzyme (as determined by rechromatography on Sephadex G-100 column) was also 29,000, suggesting that the enzyme is a monomer. Two isoelectric forms of PCM (pI = 6.1 and pI = 6.4) were detected in the purified enzyme preparation. The enzyme methylates various exogenous and endogenous proteins, including the acetylcholine receptor. Of the four different polypeptides of the acetylcholine receptor, the gamma and beta polypeptides were selectively methylated by the purified PCM. Purified Torpedo PCM is highly sensitive to sulfhydryl reagents. The competitive inhibitor of PCM S-adenosyl-L-homocysteine (AdoHcy) protected the enzyme from inactivation by sulfhydryl reagents, suggesting the existence of a cysteine residue at the active site of the enzyme. The purified PCM has a low affinity toward DEAE-cellulose and toward AdoHcy-agarose. This property, as well as the relatively high molecular weight and the marked sensitivity to sulfhydryl reagents, distinguishes between the electric organ PCM and analogous enzymes of mammalian tissues.     

The localization of protein carboxyl-methylase in sperm tails

Protein carboxyl-methylase (PCM), an enzyme known to be involved in exocytotic secretion and chemotaxis, has been studied in rat and rabbit spermatozoa. PCM activity and its substrate methyl acceptor protein(s) (MAP) were demonstrated in the supernate after solubilization of the sperm cell membrane by detergent (Triton X-100). A protein methylesterase that hydrolyzes methyl ester bonds created by PCM was demonstrated in rabbit but not in rat spermatozoa. This enzyme was not solubilized by nonionic detergent. The specific activities of PCM in rat spermatozoa from caput and cauda epididymis were similar and lower than that found in testis. By contrast, MAP substrates were low in testis and increased in parallel with sperm maturation in the epididymis. Multiple MAP were demonstrated in spermatozoa by polyacrylamide gel electrophoresis. The pattern of these proteins was similar in spermatozoa from different portions of the reproductive tract. Fractionation of heads and tails of rat spermatozoa on sucrose gradients indicated that PCM was found exclusively in the tail fraction, whereas MAP was detected both in head and tail fractions. The presence of all the components of the protein carboxyl-methylation system in spermatozoa and the localization of PCM and some of its substrates in the sperm tail are consistent with their involvement in sperm cell motility.     

Synthetic Peptides Mimic gp75 from Paracoccidioides brasiliensis in the Diagnosis of Paracoccidioidomycosis

Paracoccidioidomycosis (PCM) is a systemic granulomatous disease, endemic in Latin America, caused by the thermal dimorphic fungus Paracoccidioides brasiliensis. Although some fungal antigens have already been characterized and used for serological diagnosis, cross-reactions have been frequently observed. Thus, the examination of fungal forms in clinical specimens or isolation of P. brasiliensis by culture is still the most frequent method for the diagnosis of this mycosis. In this study, a random peptide phage display library was used to select mimotopes of P. brasiliensis, which were employed as antigens in an indirect enzyme-linked immunosorbent assay. The protective monoclonal antibody against experimental PCM (anti-gp75) was used as molecular target to screen a phage display library. That approach led to a synthetic peptide named P2, which was synthesized and tested against PCM patients' sera to check whether it was recognized. There was significant recognition of P2 by sera of untreated PCM patients when compared with normal human sera. Sera from treated PCM group, patients with other mycosis or co-infected with HIV had much lower recognition of P2 than untreated patient group. The test showed a sensitivity of 100 and 94.59% of specificity in relation to human sera control. These data indicate a potential use of P2 as diagnostic tool in PCM. Its application for serological diagnosis of PCM may contribute to the development and standardization of simpler, faster and highly reproducible immunodiagnostic tests at low cost.     

Purification and Characterization of Two Distinct Isozymes of Protein Carboxymethylase from Bovine Brain

Protein carboxymethylase (EC 2.1.1.24) from cytosol of bovine brain was found to exist as two apparent isozymes that could be separated by chromatography on DEAE-cellulose at pH 8.O. Rechromatography of the two forms, designated PCM I and PCM II, indicated that they are not interconvertible. Both enzymes have a molecular weight of 24,300 by sodium dodecyl sulfate-polyacryl-amide gel electrophoresis. PCM I consists mainly of one isoelectric form, pI 6.5, whereas PCM II resolves into two forms of pI 5.6 and 5.7. The relative amounts of PCM I and PCM II show a marked tissue dependence. Brain has approximately twice as much PCM I as II, whereas liver contains only the type II enzyme. The two enzymes were found to have similar substrate specificities when tested with five different methyl-accepting proteins. Synapsin I, a basic protein associated with synaptic vesicles, was found to be an excellent methyl-accepting protein with regard to its K_m (1.2 μM), but it exhibited a low stoichiome-try of methyl incorporation.     

Dendritic cells transfected with scFv from Mab 7.B12 mimicking original antigen gp43 induces protection against experimental Paracoccidioidomycosis

Paracoccidioidomycosis (PCM), endemic in Latin America, is a progressive systemic mycosis caused by Paracoccidioides brasiliensis (P. brasiliensis), which primarily attacks lung tissue. Dendritic cells (DCs) are able to initiate a response in naïve T cells, and they also participate in Th-cell education. Furthermore, these cells have been used for therapy in several disease models. Here we transfected DCs with a plasmid (pMAC/PS-scFv) encoding a single chain variable fragment (scFv) of an anti-Id antibody that is capable of mimicking gp43, the main antigenic component of P. brasiliensis. First, Balb/c mice were immunized subcutaneously with pMAC/PS-scFv and, after seven days, scFv protein was presented to the regional lymph nodes cells. Moreover, we showed that the DCs transfected with scFv were capable of efficiently activating proliferation of total lymph node cells and inducing a decrease in lung infection. Therefore, our results suggested that the use of scFv-transfected DCs may be a promising therapy in the paracoccidioidomycosis (PCM) model.     

The effect of dimethylsulphoxide on the microtubular system of the mouse oocyte

The effect of dimethylsulphoxide (DMSO) on the organization of the microtubular system of the mouse oocyte has been examined. Exposure to DMSO causes the immediate appearance of multiple, cold-resistant microtubular asters associated with the foci of pericentriolar material (PCM) normally present in the oocyte. More prolonged exposure to DMSO leads to progressive disassembly of the spindle, and as a result dispersal of the chromosomes and polar PCM foci occurs, and tubulin polymerization becomes confined to PCM-organized asters. Those astral microtubules located between the PCM foci and the cortex of the oocyte appear to be particularly stable, resulting in the development of lengthening radial bundles of microtubules between the PCM and the surface and the progressive movement of the PCM foci towards the centre of the cell. In contrast, after activation of the oocyte the microtubules generated in the presence of DMSO remain located in a cortical mesh. The effects of DMSO do not appear to be fully reversible in most oocytes. We discuss the implications of these results both for the cytoplasmic organization of the oocyte and zygote, and for the attempts at cryopreservation of human oocytes for therapeutic use in infertility programmes.     

Further investigations on the clastogenicity of paracetamol and acetylsalicylic acid in vitro

Paracetamol (PCM) and acetylsalicylic acid (ASA), both widely used analgesics, were tested for their clastogenicity in V79 cells in vitro. Rat liver S9 mix and primary rat hepatocytes (PRH) were used as external activation systems. ASA was found to be negative with and without activation system in concentrations up to 10(-2) M. In contrast PCM induced concentration-dependent chromosomal aberrations with and without activation system within the range of 3 x 10(-3) and 10(-2) M. The greatest effects were observed following continuous treatment with PRH activation and without external metabolization. Pulse treatments without external metabolization, with S9 mix and PRH were less effective. The clastogenic potency of PCM seems to be partly independent of metabolic activation. Although clastogenic effects in vitro were observed only in very high concentrations pharmacokinetic data and other published mutagenicity data indicate that there might be a risk for human use. Peak plasma levels of more than 10(-4) M have been reported (Forrest et al., 1982) and 2 groups of investigators (Kocisova et al., 1988; Hongslo et al., 1990) found PCM to be weakly clastogenic in human lymphocytes in vivo in the maximum human therapeutic dose range.     

HIV Immune Recovery Inflammatory Syndrome and Central Nervous System Paracoccidioidomycosis

The immune reconstitution inflammatory syndrome (IRIS) is a deregulated inflammatory response to invading microorganisms. It is manifested when there is an abrupt change in host immunity from an anti-inflammatory and immunosuppressive state to a pro-inflammatory state as a result of rapid depletion or removal of factors that promote immune suppression or inhibition of inflammation. The aim of this paper is to discuss and re-interpret the possibility of association of paracoccidioidomycosis (PCM) with IRIS in the central nervous system (CNS) in a case from Brazil published by Silva-Vergara ML. et al. (Mycopathologia 177:137–141, 6). An AIDS patient who was not receiving medical care developed pulmonary PCM successfully treated with itraconazole. The patient developed central nervous system PCM (NPCM) after starting the ARV therapy with recovery of immunity and control of HIV viral load, although it was not interpreted as IRIS by the authors, it fulfills the criteria for CNS IRIS. This could be the first case of NPCM associated with IRIS described. Although not frequent, IRIS must be considered in PCM patients and HIV, from endemic areas or patients that traveled to endemic areas, receiving ARV treatment and with worsening symptoms.     

A biomechanical role for perlecan in the pericellular matrix of articular cartilage

Chondrocytes are surrounded by a narrow pericellular matrix (PCM) that is biochemically, structurally, and biomechanically distinct from the bulk extracellular matrix (ECM) of articular cartilage. While the PCM is often defined by the presence of type VI collagen, other macromolecules such as perlecan, a heparan sulfate (HS) proteoglycan, are also exclusively localized to the PCM in normal cartilage and likely contribute to PCM structural integrity and biomechanical properties. Though perlecan is essential for normal cartilage development, its exact role in the PCM is unknown. The objective of this study was to determine the biomechanical role of perlecan in the articular cartilage PCM in situ and its potential as a defining factor of the PCM. To this end, atomic force microscopy (AFM) stiffness mapping was combined with dual immunofluorescence labeling of cryosectioned porcine cartilage samples for type VI collagen and perlecan. While there was no difference in overall PCM mechanical properties between type VI collagen- and perlecan-based definitions of the PCM, within the PCM, interior regions containing both type VI collagen and perlecan exhibited lower elastic moduli than more peripheral regions rich in type VI collagen alone. Enzymatic removal of HS chains from perlecan with heparinase III increased PCM elastic moduli both overall and locally in interior regions rich in both perlecan and type VI collagen. Heparinase III digestion had no effect on ECM elastic moduli. Our findings provide new evidence for perlecan as a defining factor in both the biochemical and biomechanical properties of the PCM.     

Carboxyl-methylation of prenylated calmodulin CaM53 is required for efficient plasma membrane targeting of the protein

Prenylation is necessary for association of the petunia calmodulin CaM53 with the plasma membrane. To determine whether post-prenylation processing of the protein was also required for plasma membrane targeting, we studied the subcellular localization of a GFP-labelled CaM53 reporter in yeast and plant cells. Blocking of carboxyl-methylation of prenylated proteins either by a specific inhibitor or in mutant yeast cells resulted in localization of green fluorescence to what appears to be the endomembrane system, in contrast with the plasma membrane localization observed in control cells. We show that a prenyl-cysteine methyltransferase (PCM) activity that carboxyl-methylates prenylated CaM53 also exists in plant cells, and that it is required for efficient plasma membrane targeting. We also report an Arabidopsis gene with homology to PCM and demonstrate that it encodes a protein with PCM activity that localizes to the endomembrane system of plant cells, similar to prenylated but unmethylated CaM53. Together, our data suggest that, following prenylation, CaM53 is probably associated with the endomembrane system, where a PCM activity methylates the prenylated protein prior to targeting it to its final destination in the plasma membrane.     

Ex vivo differentiation of umbilical cord blood progenitor cells in the presence of placental conditioned medium

Hematopoetic stem cells (HSC) are the progenitors for the lympho-hematopoietic system, with long lifespan and high proliferation potential. Transplantation of HSC from bone marrow or peripheral blood represents a standard therapy in severe hematological conditions. A possible alternative source of HSC is the umbilical cord blood, prepared by various separation procedures followed by expansion in cultures supplemented with hematopoietic growth factors. In order to check the effects of placental conditioned medium (PCM) from placental cells culture upon viability of HSC, we added plasma, PCM, dimetil sulfoxyde or hemin in HSC cultures. Flow cytometry or direct scoring of solid cultures using CD45+, CD34+, CD71+ and CD14+ fluorescent-labeled monoclonal antibodies evaluated the effects upon cell proliferation and colony forming ability of HSC cultures, versus controls. PCM produced the highest proliferation, followed by plasma, DMSO and hemin. PCM improved the survival time and maintained a higher proportion of immature cells. PCM stimulates the differentiation towards myeloid lineage progenitor cells (>90% being CD45+), increasing the percentage of CD14+, granulocites /monocytes precursors. It is highly suggestive that PCM contains growth factors or cytokines, which regulate the development of HSC. Characterization of these factors is in progress.     

Calmodulin gene family in potato: developmental and touch-induced expression of the mRNA encoding a novel isoform

Eight genomic clones of potato calmodulin (PCM1 to 8) were isolated and characterized. Sequence comparisons of different genes revealed that the deduced amino acid sequence of PCM1 had several unique substitutions, especially in the fourth Ca²⁺-binding area. The expression patterns of different genes were studied by northern analysis using the 3-untranslated regions as probes. The expression of PCM1, 5, and 8 was highest in the stolon tip and it decreased during tuber development. The expression of PCM6 did not vary much in the tissues tested, except in the leaves, where the expression was lower; whereas, the expression of PCM4 was very low in all the tissues. The expression of PCM2 and PCM3 was not detected in any of the tissues tested. Among these genes, only PCM1 showed increased expression following touch stimulation. To study the regulation of PCM1, transgenic potato plants carrying the PCM1 promoter fused to the -glucuronidase (GUS) reporter gene were produced. GUS expression was found to be developmentally regulated and touch-responsive, indicating a positive correlation between the expression of PCM1 and GUS mRNAs. These results suggest that the 5-flanking region of PCM1 controls developmental and touch-induced expression. X-Gluc staining patterns revealed that GUS localization is high in meristematic tissues such as the stem apex, stolon tip, and vascular regions.     

Relative frequency of malaria pigment-carrying monocytes of nonimmune and semi-immune patients from flow cytometric depolarized side scatter

BACKGROUND: Recently, it was observed that malaria can be detected by performing automated complete blood count analysis including depolarization measurement of scattered laser light. To explain large discrepancies in sensitivity and specificity observed in semi-immune and nonimmune malaria patients, we determined the relative frequencies of malaria pigment-carrying monocytes (PCM) by flow cytometric measurements combined with rare event analysis. METHODS: An experimental cell-sorting unit utilizing argon, krypton, and helium-neon lasers measured the relative frequencies of leukocytes of malaria patients. Single white blood cells showing high intensity in their depolarized side scatter were sorted for subsequent microscopic analysis. RESULTS: From microscopic inspection of sorted cells, we identified malaria PCM as a distinct cluster in scatter diagrams that is well separated from normal leukocytes. For nonimmune patients, the average relative frequency of PCM is 1.5 x 10(-4) (median), for semi-immune patients 8.8 x 10(-4), and for malaria-negative persons 4.4 x 10(-6). Results derived from depolarized side scatter at 488, 633, or 647 nm agree well. Furthermore, malaria pigment-carrying neutrophilic granulocytes were identified microscopically after sorting. We discuss briefly how pigment-carrying neutrophils might be differentiated from normal leukocytes and PCM by using flow cytometry and measuring depolarized side scatter at two wavelengths. CONCLUSION: Our results confirm the feasibility of malaria detection by flow cytometry for semi-immune patients and extend malaria detection to nonimmune patients with low frequencies of PCM. High sensitivity and specificity for malaria detection were obtained.     

Osteoarthritic changes in the biphasic mechanical properties of the chondrocyte pericellular matrix in articular cartilage

The pericellular matrix (PCM) is a narrow region of cartilaginous tissue that surrounds chondrocytes in articular cartilage. Previous modeling studies indicate that the mechanical properties of the PCM relative to those of the extracellular matrix (ECM) can significantly affect the stress-strain, fluid flow, and physicochemical environments of the chondrocyte, suggesting that the PCM plays a biomechanical role in articular cartilage. The goals of this study were to measure the mechanical properties of the PCM using micropipette aspiration coupled with a linear biphasic finite element model, and to determine the alterations in the mechanical properties of the PCM with osteoarthritis (OA). Using a recently developed isolation technique, chondrons (the chondrocyte and its PCM) were mechanically extracted from non-degenerate and osteoarthritic human cartilage. The transient mechanical behavior of the PCM was well-described by a biphasic model, suggesting that the viscoelastic response of the PCM is attributable to flow-dependent effects, similar to that of the ECM. With OA, the mean Young's modulus of the PCM was significantly decreased (38.7+/-16.2 kPa vs. 23.5+/-12.9 kPa, p < 0.001), and the permeability was significantly elevated (4.19+/-3.78 x10(-17) m(4)/Ns vs. 10.2+/-9.38 x 10(-17) m(4)/Ns, p < 0.01). The Poisson's ratio was similar for both non-degenerate and OA PCM (0.044+/-0.063 vs. 0.030+/-0.068, p > 0.6). These findings suggest that the PCM may undergo degenerative processes with OA, similar to those occurring in the ECM. In combination with previous theoretical models of cell-matrix interactions in cartilage, our findings suggest that changes in the properties of the PCM with OA may have an important influence on the biomechanical environment of the chondrocyte.     

Adhesion-promoting factor from embryonic fibroblasts for normal liver epithelial cells

In the present study we show that adhesion of normal rat liver epithelial cells (RL34) to substratum coated with type I collagen (collagen substratum) is promoted by a factor involved in 80% ammonium sulfate precipitated proteins from serum-free conditioned medium (PCM) of rat embryo fibroblasts. Adhesion of RL34 cells to collagen substratum was promoted dose dependently by whole PCM and the maximum effects on adhesion could be achieved by 200 micrograms/ml whole PCM. Kinetics studies with 100 micrograms/ml whole PCM showed that adhesion proceeded very slowly, taking 16 h to reach a plateau. Adhesion-promoting activity in whole PCM was sensitive to treatments with trypsin, acid, and heat but stable to dithiothreitol treatment. Further purification of whole PCM was performed using a combination of chromatography on blue Sepharose column, gel filtration column and heparin Sepharose column. The partially purified proteins, referred to as heparin PCM, are not bound or only weakly bound to heparin under physiological ion strength and pH, and the apparent molecular weight (Mr) range is estimated to be 40,000 to 60,000 from gel filtration chromatography and SDS-polyacrylamide gel electrophoresis. When whole PCM or heparin PCM was used for coating on plastic or collagen substratum, they no longer exerted the promoting activity.