Parámetros mamográficos: compresión, dosis y disconfort / Mammography parameters: compression, dose, and discomfort

Objetivo: Confirmar la importancia de la compresión en mamografía, y relacionarla con el disconfort manifestado por las pacientes. Materiales y métodos: Se emplearon 2 muestras de 402 y 268 mamografías, obtenidas en dos centros de diagnóstico que poseen el mismo equipo mamográfico pero diferentes técnicas de compresión. Las edades variaron entre los 21 y los 50 años. Resultados: Se observó una sensible disminución en la dosis recibida a mayor compresión. Sin embargo, no se obtuvo una diferencia significativa en lo que respecta a los reclamos de las pacientes en relación con el disconfort experimentado. Discusión y Conclusión: La compresión en mamografía, siguiendo los estándares internacionales de una fuerza entre 80-120 N, es efectiva en cuanto a la reducción de dosis, sin por eso ser insoportable para la paciente. Este disconfort tampoco está relacionado con la glandularidad de la mama.

Objective: To confirm the importance of compression in mammography and relate it to the discomfort expressed by the patients. Materials and methods: Two samples of 402 and 268 mammographies were obtained from two diagnostic centres that use the same mammographic equipment, but different compression techniques. The patient age range was from 21 to 50 years old. Results: A significant decrease in the dose received was observed at higher compression. However, there was no significant difference as regards patients complaining about the discomfort experienced. Discussion and Conclusion: Compression in mammography, following the international standards of a pressure between 80-120 N, is effective in reducing the dose without being unbearable for the patient. This discomfort is also unrelated to the glandularity of the breast.

Células mesenquimales de médula osea: diferenciación y potencial reemplazo neuronal / Mesenchymal stem cells: differentiation and alternative source of neural tissue

Embryonic stem cells are a population of cells located in the blastocyst, committed to specific differentiation according to spatial and temporal factors such as age and place of final location. Despite the final fate of hematic cells, hemopoietic cells retain a relative degree of plasticity dependent on environmental factors. Mesenchymal cells are a well differentiated population of bone marrow derived non hemopoietic cells with totipotential properties. The medical interest of such totipotentiality rests in the potential of such cells to repair damaged tissues. Particularly neuronal differentiation from progenitors obtained from mesenchymae non hemopoietic cells offers a new possibility in the field of neural transplantation and tissue engineering to repair functional entities in the nervous system.

Las células troncales embrionarias son totipotentes y se encuentran en pequeño número en el blastocisto donde pueden expandirse en forma indiferenciada durante un corto tiempo y de acuerdoal sitio donde se alojan, ellas adquirirán determinados fenotipos de diferenciación. Las células hemopoyéticas troncales se caracterizan por poseer un gran potencial proliferativo, cuyo modelo de regulación es jerárquico. Ellas retienen, a lo largo de su existencia, un cierto grado de plasticidad, lo cual hace que se puedan diferenciar en distintos tipos de células o de tejidos no hemopoyéticos, de acuerdo al microambiente donde se encuentran o bien a la presencia de ciertos factores estimulantes. En trabajos recientes se han podido aislar, por adherencia al plástico, en cultivo in vitro de médula ósea, células no hemopoyéticas que fueron llamadas mesenquimales por su semejanza con el tejido mesenquimal del embrión. Estas células, in vitro, pueden ser inducidas hacia nuevas líneas celulares, que se diferenciarán en nuevos tejidos. Las expectativas del beneficio terapéutico del transplante de médula ósea como el de células mesenquimales en enfermedades no hemopoyéticas son grandes, porque al utilizar tejidos o células autólogas, se evitan los graves problemas del rechazo inmunológico. En el caso del tejido nervioso la problemática de una fuente adecuada de donantes hace el tema especialmente interesante.

Cyclospora cayatanensis en pacientes con SIDA y diarrea crónica / Cyclospora cayetanensis in patients with AIDS and chronic diarrhea

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.

Cyclospora cayatanensis en pacientes con SIDA y diarrea crónica / Cyclospora cayetanensis in patients with AIDS and chronic diarrhea

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. (AU)

Células mesenquimales de médula osea: diferenciación y potencial reemplazo neuronal / Mesenchymal stem cells: differentiation and alternative source of neural tissue

Embryonic stem cells are a population of cells located in the blastocyst, committed to specific differentiation according to spatial and temporal factors such as age and place of final location. Despite the final fate of hematic cells, hemopoietic cells retain a relative degree of plasticity dependent on environmental factors. Mesenchymal cells are a well differentiated population of bone marrow derived non hemopoietic cells with totipotential properties. The medical interest of such totipotentiality rests in the potential of such cells to repair damaged tissues. Particularly neuronal differentiation from progenitors obtained from mesenchymae non hemopoietic cells offers a new possibility in the field of neural transplantation and tissue engineering to repair functional entities in the nervous system.(AU)

Las células troncales embrionarias son totipotentes y se encuentran en pequeño número en el blastocisto donde pueden expandirse en forma indiferenciada durante un corto tiempo y de acuerdoal sitio donde se alojan, ellas adquirirán determinados fenotipos de diferenciación. Las células hemopoyéticas troncales se caracterizan por poseer un gran potencial proliferativo, cuyo modelo de regulación es jerárquico. Ellas retienen, a lo largo de su existencia, un cierto grado de plasticidad, lo cual hace que se puedan diferenciar en distintos tipos de células o de tejidos no hemopoyéticos, de acuerdo al microambiente donde se encuentran o bien a la presencia de ciertos factores estimulantes. En trabajos recientes se han podido aislar, por adherencia al plástico, en cultivo in vitro de médula ósea, células no hemopoyéticas que fueron llamadas mesenquimales por su semejanza con el tejido mesenquimal del embrión. Estas células, in vitro, pueden ser inducidas hacia nuevas líneas celulares, que se diferenciarán en nuevos tejidos. Las expectativas del beneficio terapéutico del transplante de médula ósea como el de células mesenquimales en enfermedades no hemopoyéticas son grandes, porque al utilizar tejidos o células autólogas, se evitan los graves problemas del rechazo inmunológico. En el caso del tejido nervioso la problemática de una fuente adecuada de donantes hace el tema especialmente interesante.(AU)

Disturbance of cellular iron uptake and utilisation by aluminium.

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.

[Characteristics of murine primordial germ cells and their relation with hemopoiesis]. / Características de las células primordiales germinales murinas y su relación con la hemopoyesis.

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.

Características de las células primordiales germinales murinas y su relación con la hemopoyesis. / [Characteristics of murine primordial germ cells and their relation with hemopoiesis]

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.

In vitro inhibition of murine hematopoietic progenitors and stromal cells by vinorelbine.

Hematopoietic progenitor colony assays were used to establish the effects of the vinca alkaloid vinorelbine (VRB) on murine bone marrow. The in vitro growth of colony-forming units-granulocyte/macrophage (CFU-GM), burst forming units-erythroid (BFU-E) and colony-forming units-mix (CFU-mix) was dose-dependently inhibited by VRB. The highest dose assayed (0.02 microg/ml) suppressed all of the different progenitor cells by 100%. A comparison of the dose-response curves showed that CFU-GM, BFU-E, and CFU-mix exhibited similar-patterns of sensitivity to the cytotoxic action of VRB. Long-term bone marrow cultures have provided a valuable in vitro model for studying the role of the microenvironment of bone marrow. Cellularity of stromal layers was reduced with increasing doses of VRB. The appearance of these layers was altered minimally with the lowest dose used; a gradual loss of cellularity was seen in cultures exposed to 0.05 and 0.075 microg/ml; and a marked loss at the dose of 0.1 microg/ml. Our results show that VRB has an important effect on hematopoietic progenitors at the highest dose tested, while the stromal cells were not affected at a similar dose (0.025 microg/ml), suggesting that the stroma is more resistant to this drug.

Interference of aluminium on iron metabolism in erythroleukaemia K562 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.

[Analysis of hemopoietic progenitor cells in bone marrow and peripheral blood samples which have undergone different periods of cryopreservation]. / Analisis de progenitores hemopoyéticos en muestras de medula osea y de sangre periférica en periodos variables de criopreservación.

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.

Analisis de progenitores hemopoyéticos en muestras de medula osea y de sangre periférica en periodos variables de criopreservación. / [Analysis of hemopoietic progenitor cells in bone marrow and peripheral blood samples which have undergone different periods of cryopreservation]

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.

[Classic strategies for diagnosis of cryptosporidiosis in patients with AIDS and chronic diarrhea]. / Estrategias clásicas para el diagnóstico de criptosporidiosis en pacientes con SIDA y diarrea crónica.

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.

[In vitro study of hemopoietic progenitors in human umbilical cord blood treated with different cytokines and autologous serum]. / Estudio in vitro de progenitores hemopoyéticos de sangre de cordón umbilical humano frente a diferentes citoquinas y suero autólogo.

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.

[Large granular lymphocytic leukemia. Case report with scarce expression in peripheral blood]. / Leucemia de linfocitos grandes granulares. Presentación de un caso con escasa expresión en sangre periférica.

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.

[Morphological study of Enterocytozoon bineousi in patients with AIDS and chronic diarrhea]. / Estudio morfólogico de Enterocytozoon bieneusi en pacientes con SIDA y diarrhea crónica.

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.