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Purpose: Microsporidiosis is an opportunistic infection that produces chronic diarrhoea and cholangiopathy in patients with AIDS, mainly caused by two species of microsporidia, Enterocytozoon bieneusi and Encephalitozon intestinalis. The aim of this work was to develop an integral system for the diagnosis of microsporidiosis of the intestine and biliary tract in HIV-infected patients, comprising microscopic and molecular techniques., Methods: The study population comprised 143 adult patients of both sexes with diagnosis of HIV infection, with chronic diarrhoea, and with or without HIV-associated cholangiopathy. Stool studies for microsporidia identification of spores were performed on each patient. A video esofagogastroduodenoscopy with biopsy collection was also carried out for routine histology and semi-thin sections stained with Azure II. Species identification was carried out by transmission electron microscopy and/or polymerase chain reaction for the species E. bieneusi and E. intestinalis., Results: Out of the 143 patients a total of 12.6% (n = 18) were infected with microsporidia. Microsporidia species identified in most cases was E. bieneusi (16/18 cases), followed by E. intestinalis (4/18), all of these last ones in coinfection with E. bieneusi., Conclusions: Clinical, imaging, microscopic and molecular analyses, when applied in a systematic and integrated approach, allow diagnosis and identification of microsporidia at species level in AIDS patients with chronic diarrhoea, and with or without HIV-associated cholangiopathy.

Microsporidia are eukaryotic, intracellular obligate parasites that infect invertebrate and vertebrate animals, and have emerged as important opportunistic parasites in AIDS patients. We used light microscopy to detect microsporidial spores in stool samples of a domestic cat confirmed as Encephalitozoon intestinalis by PCR, owned by an AIDS patient with chronic diarrhea and E. intestinalis infection. Cats can be considered hosts of E. intestinalis., (Copyright © 2012 Elsevier B.V. All rights reserved.)

Background: Several species of microsporidia and coccidia are protozoa parasites responsible for cholan-giopathy disease in patients infected with human immunodeficiency virus (HIV). The goals of this work were to identift opportunistic protozoa by molecular methods and describe the clinical manifestations at the gastrointestinal tract and the biliary system in patients with AIDS-associated cholangiopathy from Buenos Aires, Argentina., Material and Methods: This study included 11 adult HIV-infected individuals with diagnosis ofAIDS- associated cholangiopathy. An upper gastrointestinal endoscopy with biopsy specimen collection and a stool analysis for parasites were performed on each patient. The ultrasound analysis revealed bile ducts compromise. An endoscopic retrograde cholangiopancreatography and a magnetic resonance cholangiography were carried out. The identification to the species level was performed on biopsy specimens by molecular methods., Results: Microorganisms were identified in 10 cases. The diagnosis in patients with sclerosing cholangitis was cryptosporidiosis in 3 cases, cystoisosporosis in 1 and microsporidiosis in 1. In patients with sclerosing cholangitis and papillary stenosis the diagnosis was microsporidiosis in 2 cases, cryptosporidiosis in 2 and cryptosporidiosis associated with microsporidiosis in 1. In 3 cases with cryptosporidiosis the species was Cryptosporidium hominis, 1 of them was associated with Enterocytozoon bieneusi, and the other 2 were coinfected with Cryptosporidium parvum. In the 4 cases with microsporidiosis the species was Enterocytozoon bieneusi., Conclusions: These results suggest that molecular methods may be useful tools to identify emerging protozoa in patients with AIDS-associated cholangiopathy.

The complex and variable composition of natural sediments makes it difficult to predict the bioavailability and bioaccumulation of sediment-bound contaminants. Several approaches, including an experimental model using artificial particles as analogues for natural sediments, have been proposed to overcome this problem. For this work, we applied this experimental device to investigate the uptake and bioaccumulation of As(III) by the freshwater oligochaete Lumbriculus variegatus. Five different particle systems were selected, and particle-water partition coefficients for As(III) were calculated. The influence of different concentrations of commercial humic acids was also investigated, but this material had no effect on bioaccumulation. In the presence of particulate matter, the bioaccumulation of As(III) by the oligochaetes did not depend solely on the levels of chemical dissolved but also on the amount sorbed onto the particles and the strength of that binding. This study confirms that the use of artificial particles may be a suitable experimental model for understanding the possible interactions that may occur between contaminants and particulate matter. In addition, it was found that the most hydrophobic resin induced an increase in arsenic bioavailability, leading to the highest bioaccumulation to L. variegatus compared with animals that were exposed to water only., (© Springer Science+Business Media, LLC 2011)

Cystoisospora belli is a coccidian protozoan that can cause chronic diarrhoea, acalculous cholecystitis and cholangiopathy in AIDS patients. We applied molecular methods to identify Cystoisospora at species level in AIDS patients presenting with and without the presence of unizoites in lamina propria. Coprological and histological analyses were performed in stool and/or biopsy samples from 8 Cystoisospora-infected patients. DNA from the same samples was used to amplify 2 fragments of the SSU-rRNA gene and the ITS-1 region. Sequencing of the resulting amplicons identified C. belli infections in all cases, independent of the presence or absence of unizoite tissue cysts. Further work should be considered in order to find molecular targets related to strain variations in C. belli.

Cryptosporidium hominis (C hominis) is the most common protozoan parasite recognized in human patients with AIDS. We report the clinical features of a patient with chronic diarrhea and AIDS-related sclerosing cholangitis. The imaging studies with ultrasonography and endoscopic retrograde cholangiopancreatography disclosed intrahepatic and extrahepatic bile duct changes identical to those seen in sclerosing cholangitis. C hominis was detected in the duodenum and peri-papillary duodenum by means of light microscopy and confirmed by nested polymerase chain reaction (PCR) amplification from fresh biopsy specimens followed by restriction length polymorphism analysis. Chominis infection should be suspected in our country in patients with advanced immunodeficiency and AIDS-related sclerosing cholangitis.

Sarcocystis sp is a tissue coccidian parasite in humans that causes intestinal and muscular sarcocystosis in immunocompetent patients. Intestinal sarcocystosis can be diagnosed at the tissue level in the lamina propria of the small bowel and by fecal examination. Muscular sarcocystosis is diagnosed by microscopic examination of muscle biopsies. This report describes a case of systemic sarcocystosis in an HIV-infected patient. We studied a 31-year-old patient with AIDS, chronic diarrhea, cholestatic hepatitis, and musculoskeletal pain by stool analysis and endoscopy with duodenal and liver biopsy specimens that were processed for routine histology. The microgamete and macrogamete stages of Sarcocystis sp were present in the lamina propria, with sporulated oocysts in feces. Schizont stages of the protozoa were found in liver biopsy. In summary, sarcocystosis should be considered another opportunistic infection in HIV-infected patients.

Aluminum (Al) and iron (Fe) share several physicochemical characteristics and they both bind to transferrin (Tf), entering the cell via Tf receptors (TfR). Previously, we found similar values of affinity constant for the binding of TfR to Tf carrying either Al or Fe. The competitive interaction between both metals prevented normal Fe incorporation into K562 cells and triggered the upregulation of Fe transport. In the present work we demonstrated that Al modified Fe uptake without affecting the expression of Tf receptors. Both TfR and TfR2 mRNA levels, evaluated by RT-PCR, and TfR antigenic sites, analyzed by flow cytometry, were found unchanged after Al exposure. In turn, Al did induce upregulation of non-Tf bound Fe (NTBI) uptake. This modulation was not due to intracellular Fe decrease since NTBI transport proved not to be regulated by Fe depletion. Unlike its behavior in the presence of Tf, Al was unable to compete with NTBI uptake, suggesting that both metals do not share the same alternative transport pathway. We propose that Al interference with TfR-mediated Fe incorporation might trigger the upregulation of NTBI uptake, an adaptation aimed at incorporating the essential metal required for cellular metabolism without allowing the simultaneous access of a potentially toxic metal.

Cyclospora spp. is a protozoan parasite responsible for significant gastrointestinal disease in patients infected with the human immunodeficiency virus. We report the clinical features of two patients with chronic diarrhea and intestinal cyclosporosis caused by Cyclospora cayetanensis. The average value for CD4 count in these patients was lower than or equal to 100 cells/mm3. The oocysts were detected in smears from stool samples stained with modified acid-fast or safranin technique. Light microscopy revealed parasites in the enterocytes and these parasites were associated with villous atrophy. Cyclospora cayetanensis infection might be an important cause of diarrhea in patients with AIDS in Argentina.

Aluminium (Al) affects erythropoiesis but the real mechanism of action is still unknown. Transferrin receptors (TfR) in K562 cells are able to bind Tf, when carrying either iron (Fe) or Al, with similar affinity. Then, the aim of this work was to determine whether Al could interfere with the cellular Fe uptake and utilisation. K562 cells were induced to erythroid differentiation by either haemin (H) or sodium butyrate (B) and cultured with and without Al. The effect of Al on cellular Fe uptake, Fe incorporation to haem and cell differentiation was studied. H- and B-stimulated cells grown in the presence of 10 microM Al showed a reduction in the number of haemoglobinised cells (by 18% and 56%, respectively) and high amounts of Al content. Al(2)Tf inhibited both the (59)Fe cellular uptake and its utilisation for haem synthesis. The removal of Al during the (59)Fe pulse, after a previous incubation with the metal, allowed the cells to acquire Fe quantities in the normal range or even exceeding the amounts incorporated by the respective control cells. However, the Fe incorporated to haem could not reach control values in B-stimulated cells despite enough Fe acquisition was observed after removing Al. Present results suggest that Al might exert either reversible or irreversible effects on the haemoglobin synthesis depending on cellular conditions.

Primordial germ cells (PGC) are a population of cells characterised by a positive reaction to alkaline phosphatase, usually present in the mouse embryo at 7.5 days post coitus (dpc). These cells migrate through various tissues before they become incorporated into the gonadal ridges. Hematopoiesis is a complex developmental system in which the hemopoietic stem cells (HSC) were experimentally shown to have been derived from a single multipotent stem cell. PGC, as well as HSC are regulated by a range of growth factors that control both proliferative and differentiative processes. Leukemia inhibitory factor (LIF) is a cytokine that regulates the differentiation and the totipotentional phenotype of PGC. Recently, other growth factors, such as stem cell factor (SCF), macrophage growth factor (MGF), and forskolin (FRKL) have been proposed as the possible in vivo and in vitro regulators for PGCs and HSCs. Induction of hematopoiesis in an embryonic germ cell derived from PGCs indicates that germ cells acquire the potentiality to differentiate toward hematopoietic cells. The coincidental presence of both PGCs and HSCs at the sites where early hemopoiesis is established, together with similar growth factor requirements support the hypothesis that PGCs may also be considered hemopoiesis initiating cells.

It has been suggested that aluminium (Al) has a deleterious effect on erythropoiesis. However, there is still uncertainty as to its action mechanism. The present work was designed to determine how Al could affect the iron (Fe) metabolism in the human erythroleukaemia cell line K562. These cells, that express surface transferrin receptors (TfRs), were induced to erythroid differentiation by either haemin or hydroxyurea in 72 h cultures in media containing apotransferrin (apoTf). In the presence of aluminium citrate, the number of benzidine-positive cells decreased 18% when the cultures were induced by haemin, and 30% when hydroxyurea was the inducer. Cell viability was always unaffected. From competition assays, surface binding of 125I-Tf-Fe2 was found to be inversely related (p < 0.05) to Tf-Al2 concentration (from 2.5 to 10 nM). The dissociation constants (Kd) of the binding reaction between TfRs and the ligands Tf-Fe2 and Tf-Al2 were calculated. Kd values of the same order of magnitude demonstrated that TfR has a similar affinity for Tf-Fe2 (Kd = 1.75 x 10(-9) M) and Tf-Al2 (Kd = 1.37 x 10(-9) M). The number of surface TfRs, measured by kinetic 125I-Tf-Fe2 binding assays, was higher in induced cells cultured in the presence of Al. Nevertheless, in spite of the inhibition of cell haemoglobinization observed, 59Fe incorporation values were not different from those measured in control cultures for 72 h. As a consequence, it can be suggested that cellular Fe utilisation, and not Fe uptake, might be the main metabolic pathway impaired by Al.

Bone marrow (BM) and peripheral blood stem cell (PBSC) samples from patients undergoing autologous transplant were tested to evaluate the effects of cryopreservation. Cell viability was assessed as well as the proliferative capability of CFU-GM and BFU-E (myeloid and erythroid progenitors respectively). Moreover, long term culture (LTC) of stromal cells was used to test their functionality. A total of 23 samples were studied: 5 from AML patients, 7 MM, 6 NHL, 3 ALL and 2 HL. Nine patients received autologous bone marrow transplant (ABMT) and the remaining 14 PBSC. The cells were frozen during 24 to 33 days before infusion and 16 to 40 months before culture. Forty percent of AML and MM samples gave rise to colonies in vitro while the other hematology diseases tested showed colony growth in almost 100% of the cases. Samples from patients with lymphoid diseases exhibited a good correlation between the percentage of CD34+ cells and the number of colonies developed in culture. Nevertheless, there was no correlation when ALL and MM were tested suggesting that the underlying disease may have affected the growth in culture. The stromal layer was fully developed on BM samples, but on PBSC samples it only generated macrophages and fibroblasts. Our results suggest that the efficacy of cryopreservation of hematopoietic cells can be measured by means of CFU-GM and BFU-E culture and that the period the samples remained frozen did not affect the growth capability of the cells.

Cryptosporidium sp., a protozoa organism, has been increasingly recognized in association with severe enteritis in patients with the Acquired Immunodeficiency Syndrome. The studied subjects included 84 adult patients with AIDS and chronic diarrhea. We describe 14 patients with intestinal infection caused by Cryptosporidium sp. The mean CD4 count in these patients was < or = 300 cells/mm3 (7 out of 14). Examination of duodenal aspirates and feces included dimethylsulfoxide, auramine and acid-fast preparation of concentrated samples. We carried out videoesophagogastroduodenoscopy (VEDA) to visually inspect the mucosa and obtain biopsy specimens. VEDA revealed granular duodenum in ten patients and jasper duodenum in one of them. Duodenal biopsy specimens were stained with hematoxylin-eosin, Giemsa and Azure II. Histologic changes included atrophy (3/14), duodenitis (2/14) or both (3/14). Transmission electron microscopy was used for the identification of developmental stages of Cryptosporidium sp.

Unlabelled: The aim was to obtain the ex vivo expansion of human umbilical cord blood (HUCB) cells. A total of 19 samples were assayed to evaluate the number and type of hemopoietic progenitor cells, their proliferating capacity and the stimulating potency of cord blood serum., Methods: a) CFU-GM, CFU-GEMM and BFU-E cultures in the presence of CSF, BM serum or HUCB serum; b) 35 day LTC in liquid media whether in presence of IL-3 + GM-CSF + SCF or autologous serum (AS). Cells were demidepopulated at 7-day intervals and fresh medium and cytokines were added. Harvested cells were cultured in bone marrow (BM)/ SM and colonies were evaluated after 10 days., Results: The mean number of CFU-GM was similar to BM values; the maximum number of colonies was observed at day 7 and remained high until day 21 whether in addition of cytokines or AS. A total of 8 samples gave rise to colonies up to day 35; these samples showed higher values than BM in SM; HUCB serum has a great stimulating effect on BM cells and HUCB cells compared with nonspecific stimulating factors; moreover, HUCB showed a large dispersion., Conclusion: 1) HUCB contains a high number of hemopoietic progenitor cells with a large dispersion coefficient, 2) HUCB plasma has a great stimulatory capacity, 3) it is possible to induce the expansion of HUCB progenitors in LTC either in the presence of cytokines or of AS without loss of potency.

Microsporidia are protozoan parasites responsible for significant gastrointestinal disease in patients infected with the human immunodeficiency virus. We report the clinical features of three patients with chronic diarrhea and intestinal microsporidiosis caused by Enterocytozoon bieneusi. The average value for CD4 in these patients was < or = 50 cells/mm3. The spores were detected in smears from stool samples and duodenal aspirates stained with trichrome blue in all patients. Light microscopy of semi-thin plastic sections revealed parasites and spores in the enterocytes and were associated with villous atrophy (2 out of 3). Thin section-electron microscopy showed a variety of developmental stages of the microsporidio. Patients treated with Albendazole had an unsatisfactory clinical response to therapy. Enterocytozoon bieneusi infection may be an important cause of diarrhea in patients with AIDS in our country.

The case of a 33 year old woman with a large granular lymphocytic leukemia is presented. The main symptoms were neutropenia and recurrent respiratory bacterial infections. No enlargement of the liver, spleen or lymph nodes was noted. Circulating lymphocytes averaged 3000/microliter with 35% of large granular cells. The bone marrow biopsy showed lymphatic infiltration with both nodular and interstitial pattern. Lymphocytes bore the T suppressor phenotype (CD8+, CD45 RO+, CD20-, kappa-, lambda-). Cytogenetic studies revealed a low expression clone with 7q-: del (7)(q36). Gene rearrangements for immunoglobulins or T-cell receptors could not be demonstrated by Southern Blot. Bone marrow cultures grew normally while both normal and patient bone marrow showed marked inhibition when incubated with patients serum. Normalization of the peripheral granulocytic count was obtained with prednisone, while granulocytic-stimulating factors, chlorambucil, and cyclosporine A were partially active or inactive. We suggest that this case represents a form of the lymphoproliferative disease of granular lymphocytes. To our knowledge, the deletion of the long arm of chromosome 7 has not been described in this disease.

Occurrence of vomiting and diarrhea in patients with acquired immunodeficiency syndrome was most frequently attributed to enteropathogens organism that invade the gastrointestinal tract because of the immunologic unbalance of the host... Among several causes the cryptosporidium has been detected quite often and its predominant localization was the gastrointestinal tract, although other extraintestinal sites has also been reported. In both cases, erosive congestive gastritis was found, while histological examination showed cryptosporidium in gastric biopsy specimens.

Positive and negative signals are crucial in the regulation of the hematopoietic system. In the last 30 years, more than 20 molecules (glycoproteins) with biological activity upon the hematopoietic progenitor cells and even on the mature blood cells have been purified. The best known of these biomolecules are the hematopoietic growth factors (colony stimulating factors and interleukins), which are able to stimulate bone marrow cells to give mature progeny. At present, not only the sequence of the majority of these glycoproteins and their codifying genes has been determined, but also their target cells and cellular receptors. Research studies of the interaction between the hematopoietic progenitor cells and their stimulating and inhibiting factors are very helpful in the development of clinical trials and have become important tools to explore the origin of a great number of hematological diseases. However, the mechanisms underlying growth/inhibitory factor production and progenitor cell proliferation remain poorly understood.

The object of this study was to determine whether the "in vitro" parameters of medullary and blood granulopoiesis in patients with MDS, furnish information of either prognostic or diagnostic value. This study covered 94 patients with MDS. All patients were studied at the onset of disease. In order to identify the factors related to patients' survival, Cox Multiple Regression analysis was performed by the BMD P2L program. When analyzing by means of actuarial curves the survival probability of patients with benign development versus those of malignant development (those who developed ANLL), the significance between both groups was p = 0.0001. Different variables of patients included in this study were analyzed and all showed great significances. Fab: p = 0.0022, disease evolution: p = 0.0001 and presence of blastic aggregates: p = 0.0011. Cox's regression analysis revealed that the only predictable survival variable is the presence of blastic colonies and/or clusters. Accordingly, two groups were constructed: favourable and unfavourable. In the favourable group, 40% of the patients belonged to the RA group, while in the unfavourable group, 55% belonged to the RAEB group. This study shows the validity of the elaboration of prognostic groups in MDS according to the presence of blastic colonies and/or clusters in CFUGM medullary and/or peripheral cultures. The "in vitro" myeloid progenitors culture techniques may therefore be advantageously applied in these disorders for formulating a diagnosis and predicting the patient's short term evolution.

Myelodysplastic syndromes (SMD) were studied in 58 patients (37 men, 21 women; mean age 61 years, range 18-81) who were grouped according to FAB criteria (Table 1). None of them showed a secondary SMD to medullary toxic agents or cytostatic treatments although 5 presented concomitant neoplastic disease. Morphologic alterations in peripheral blood smears and bone marrow were registered by 3 hematologists working independently. The intracellular and extracellular iron deposits were evaluated in every case with Perls; peroxidase activity was determined in 16 patients and intraleucocitary alkaline phosphatase reaction was carried out in 17 patients. Twenty five patients (43%) had refractory anemia (RA); 10 (17%) sideroblastic anemia; 13 (25%) refractory anemia with excess of blasts (AREB); 3 (5%) AREB in transformation (AREB-T) and 7 myelomonocytic leukemia (LMMC). Clinical manifestations at diagnosis are described in Table 2. In the observation period there were cases of anemia requiring transfusion, bacterial infections, muco-cutaneous hemorrhage and hemorrhagic episodes in the central nervous system. In the bone marrow smears the cellularity was normal or increased in 53 cases and diminished in only 3. The degree of dysplastic characteristics (erythroid, granulocytic and megakaryocytic) ranged from low to severe. It was low in most of AR, being the erythroid population the most affected in AS and the granulocytic one in AREB and AREB-T. Patients with LMMC showed similar characteristics to those with myeloproliferative syndromes and the differential diagnosis were sometimes difficult, accounting for their separate inclusion in Table 4. Out of 23 patients, 5 presented clonal pathology detected in cytogenetic studies.(ABSTRACT TRUNCATED AT 250 WORDS)