Maturation and development of fetal pig intestinal tissue in immunodeficient mice

Purpose: This study aimed to compare the degree of maturation and development of fetal pig segmental intestinal tissue with that of spheroids created by in-vitro reaggregation of dissociated fetal intestinal cells after transplantation into immunodeficient mice. Methods: Fetal pig small intestines were transplanted as segmental grafts into the omentum and subrenal capsules of immunodeficient mice or enzymatically treated to generate single cells. Spheroids made by in-vitro reaggregation of these cells were transplanted into the subrenal capsules of immunodeficient mice. The segmental grafts and spheroids were harvested four and eight weeks after transplantation, and the structural maturity and in-vivo development of these specimens were histologically evaluated. Results: The spheroids were engrafted and supplied blood vessels from the host mice, but an intestinal layered structure was not clearly observed, and there was almost no change in size. On the other hand, the segmental grafts formed deep crypts in the mucus membrane, the inner circular layer, and outer longitudinal muscles. The crypts of the transplanted grafts harvested at eight weeks were much deeper, and the smooth muscle layer and the enteric nervous system were more mature than those of grafts harvested at the fourth week, although the intestinal peristaltic wave was not observed. Conclusions: Spheroids created from fetal small intestinal cells could not form layered structures or mature sufficiently. Conversely, segmental tissues structurally matured and developed after in-vivo transplantation and are therefore potential grafts for transplantation.

Techniques of fragile renal organoids transplantation in mice

Purpose: This study aimed to develop a microsurgical technique to transplant extremely fragile renal organoids in vivo, created by in-vitro reaggregation of metanephros from fetal mice. These organoids in reaggregation and development were examined histologically after transplantation under the renal capsule. Methods: Initially, metanephros from fetal mice were enzymatically treated to form single cells, and spheroids were generated in vitro. Under a microscope, the renal capsule was detached to avoid bleeding, and the outer cylinder of the indwelling needle was inserted to detach the renal parenchyma from the renal capsule using water pressure. The reaggregated spheroid was aspirated from the culture plate using a syringe with an indwelling needle outer cylinder and carefully extruded under the capsule. Pathological analysis was performed to evaluate changes in reaggregated spheroids over time and the effects of co-culture of spinal cord and subcapsular implantation on maturation. Results: In vitro, the formation of luminal structures became clearer on day 5. These fragile organoids were successfully implanted without tissue crapes under the renal capsule and formed glomerular. The effect of spinal cord co-transplant was not obvious histrionically. Conclusions: A simple and easy method to transplant fragile spheroids and renal under the renal capsule without damage was developed.

Remote ischemic preconditioning and tacrolimus in the fetal small bowel transplant in mice.

PURPOSE:: To evaluate the effect of remote ischemic preconditioning (IPC-R) in the fetal small bowel transplantation model. METHODS:: Two groups were constituted: The Isogenic transplant (ISO, C57BL/6 mice, n=24) and the allogenic transplant (ALO, BALB/c mice, n=24). In each group, the animals were distributed with and without IPC-R. It was obtained the following subgroups: Tx, IPC-R, Fk, IPC-Fk, in both strains. Intestinal grafts were stained with hematoxylin and eosin and immunohistochemically. RESULTS:: The graft development evaluation in ISO group showed that IPC-R reduced the development compared with ISO-Tx (5.2±0.4 vs 9.0±0.8) and IPC-R-Fk increased the graft development compared with IPC-R (11.2±0.7 and 10.2±0.8). In ALO group, IPC-Fk increased the development compared with ALO-Tx and ALO with IPC-R (6.0±0.8, 9.0±1.2, 0.0±0.0, 0.5±0.3). The PCNA expression was increased in ISO group treated with Fk and IPC-R compared to other groups (12.2±0.8 vs Tx: 8.8±0.9, IPC-R: 8.0±0.4 and Fk: 9.0±0.6). The graft rejection was lower in groups treated with IPC-R (-18%), Fk (-68%) or both (-61%) compared with ALO-Tx. CONCLUSION:: Remote ischemic preconditioning showed benefic effect even associate with Tacrolimus on the development and acute rejection of the fetal small bowel graft in the Isogenic and Allogenic transplants.

Remote ischemic preconditioning and tacrolimus in the fetal small bowel transplant in mice

PURPOSE:To evaluate the effect of remote ischemic preconditioning (IPC-R) in the fetal small bowel transplantation model.METHODS:Two groups were constituted: The Isogenic transplant (ISO, C57BL/6 mice, n=24) and the allogenic transplant (ALO, BALB/c mice, n=24). In each group, the animals were distributed with and without IPC-R. It was obtained the following subgroups: Tx, IPC-R, Fk, IPC-Fk, in both strains. Intestinal grafts were stained with hematoxylin and eosin and immunohistochemically.RESULTS:The graft development evaluation in ISO group showed that IPC-R reduced the development compared with ISO-Tx (5.2±0.4 vs 9.0±0.8) and IPC-R-Fk increased the graft development compared with IPC-R (11.2±0.7 and 10.2±0.8). In ALO group, IPC-Fk increased the development compared with ALO-Tx and ALO with IPC-R (6.0±0.8, 9.0±1.2, 0.0±0.0, 0.5±0.3). The PCNA expression was increased in ISO group treated with Fk and IPC-R compared to other groups (12.2±0.8 vs Tx: 8.8±0.9, IPC-R: 8.0±0.4 and Fk: 9.0±0.6). The graft rejection was lower in groups treated with IPC-R (-18%), Fk (-68%) or both (-61%) compared with ALO-Tx.CONCLUSION:Remote ischemic preconditioning showed benefic effect even associate with Tacrolimus on the development and acute rejection of the fetal small bowel graft in the Isogenic and Allogenic transplants.(AU)

Remote ischemic preconditioning and tacrolimus in the fetal small bowel transplant in mice

ABSTRACT PURPOSE: To evaluate the effect of remote ischemic preconditioning (IPC-R) in the fetal small bowel transplantation model. METHODS: Two groups were constituted: The Isogenic transplant (ISO, C57BL/6 mice, n=24) and the allogenic transplant (ALO, BALB/c mice, n=24). In each group, the animals were distributed with and without IPC-R. It was obtained the following subgroups: Tx, IPC-R, Fk, IPC-Fk, in both strains. Intestinal grafts were stained with hematoxylin and eosin and immunohistochemically. RESULTS: The graft development evaluation in ISO group showed that IPC-R reduced the development compared with ISO-Tx (5.2±0.4 vs 9.0±0.8) and IPC-R-Fk increased the graft development compared with IPC-R (11.2±0.7 and 10.2±0.8). In ALO group, IPC-Fk increased the development compared with ALO-Tx and ALO with IPC-R (6.0±0.8, 9.0±1.2, 0.0±0.0, 0.5±0.3). The PCNA expression was increased in ISO group treated with Fk and IPC-R compared to other groups (12.2±0.8 vs Tx: 8.8±0.9, IPC-R: 8.0±0.4 and Fk: 9.0±0.6). The graft rejection was lower in groups treated with IPC-R (-18%), Fk (-68%) or both (-61%) compared with ALO-Tx. CONCLUSION: Remote ischemic preconditioning showed benefic effect even associate with Tacrolimus on the development and acute rejection of the fetal small bowel graft in the Isogenic and Allogenic transplants.

Estudo estrutural do pênis de fetos humanos normais e anencéfalos no segundo trimestre de gestação / Structural study of the penis of normal and anencephalic human fetuses in the second trimester of pregnancy

A anecencefalia é o Defeito do Tubo Neural (DTN) mais severo em fetos humanos. Há uma demanda crescente para reposição tissular em doenças crônicas e cirurgias reconstrutoras. Tecidos fetais têm sido utilizados como substitutos para órgãos sólidos. Comparar a estrutura e morfologia do corpo cavernoso e corpo esponjoso de pênis de fetos humanos anencéfalos e de controle a fim de propor um novo modelo para estudos biológicos e transplantes teciduais. Foram estudados 11 pênis de fetos de controle de 14 a 23 Semanas Pós Concepção (SPC), e cinco pênis de fetos anencéfalos de 18 a 22 SPC. Os órgãos foram removidos e processados pelas técnicas histo e imunohistoquímicas rotineiras. A análise do tecido conjuntivo, células musculares lisas e fibras elásticas foram realizadas em lâminas dos espécimes. Os dados foram expressos em Densidade de àrea (Da) utilizando-se um software de processamento digital. As médias foram comparadas utilizando-se o Teste - T não pareado e quando aplicável, a regressão linear simples foi utilizada. Foi considerada significância estatística se p<0,05. O septo intercavernoso encontrava-se presente em todas as amostras. Não foram observadas diferenças da Da do tecido colágeno e musculatura lisa dos pênis de fetos anencéfalos quando comparados aos normais. A regressão linear simples sugere que durante o desenvolvimento humano há um aumen2to gradual do tecido colágeno (R2=0,45) e uma diminuição da musculatura lisa (R =0,62) no corpo cavernoso de ambos os grupos. A elastina encontrava-se presente apenas em fetos a partir da 20ª SPC. Não houve diferença na estrutura da genitália entre fetos normais e enencéfalos. Apresença da elastina em fetos a partir da 20ª SPC é um dado objetivo da manutenção da capacidade de ereção nestes grupos. A histo e imunohistoquímica sugerem que o desenvolvimento do pênis destes fetos encontra-se inalterado. Futuros estudos deverão ser realizados com o objetivo de avaliar fetos anencéfalos como um potencial ...

Anencephaly is the most severe neural tube defect (NTD) in human fetuses. There is an increasing need for tissue replacement in chronic diseases and reconstructive surgeries. Fetal tissues have been used as a substitute for native organs. Compare the structure and morphology of the corpora cavernosa and spongiosum of penises from anencephalic and normal human fetuses to propose a new model for biological studies and tissue transplantation. We studied 11 penises from normal human fetuses, aged 14 to 23 weeks post-conception (WPC), and 5 penises from anencephalic fetuses, aged 18 to 22 WPC. The organs were removed and processed by routine histological and immunolabeling techniques. Analysis of connective tissue (Cot), smooth muscle (SMC) and elastic fibers (EF) were performed in sections. Data were expressed as area density (Ad) using digital processing and software. Means were statistically compared using the unpaired t test and linear regression was performed. Statistical significance was considered if p < 0.05. The Intracavernosal septum was present in all samples. We did not observe differences in the Ad of Cot and SMC in the penises of anencephalic fetuses when compared to normal ones. The simple linear regression suggested that during human development there is a gradual increase in Cot (R2= +0.45) and a decrease of SMC (R2=- 0.62) in the corpora cavernosa in both groups studied. Elastin was observed only in fetuses from 20th WPC. There was no difference in the structure of the corpora cavernosa and corpus spongiosum of anencephalic fetuses compared to normal ones. Elastin was documented from 20th WPC, which suggests the maintenance of erectile function. Histochemistry and immunolabeling suggested that penile shaft development is maintained and unaltered in anencephalic fetuses. Further studies should be performed to analyze anencephalic fetuses as a potential tissue donating group and a model for biological studies

[An exploratory study regarding the hypothetical human embryo donation in Chile]. / Un estudio exploratorio sobre la donación hipotética de embriones humanos en Chile.

OBJECTIVE: To explore opinions of patients who undergone to complex ART towards gamete and embryo donation, as well as the reasons to do it or not. PATIENTS AND METHODS: The seat was the Hospital Clínico de la Universidad de Chile. There were interviewed ten participants (seven women, three men), who had undergone at least to one ART, without comprising of donation programs. It was a cross-sectional study of descriptive bioethics, done with ethnographic qualitative methodology with a semistructured interview applying speech analysis to the resulting text. RESULTS: Regarding embryo donation, six participants would accept to donate them, five to fertility therapy and one to research. Regarding the cryopreservation, three participants would always accept it, and three with some restrictions, just one on them would rather to discard instead of donating a cryopreserved embryo. DISCUSSION: It could be suggested: gamete donation is more commented and generally accepted; embryo donation is a more conflicting and less discussed subject, as much to donate as to accept; cryopreservation is a complex subject, commented but also conflicting, whose acceptance or not, as well as the destiny of the probably cryopreserved embryos, depends on the believes that participants have about the origin of the life, personal ethics, and the religion. It could be possible to say that a hypothesis constructed in this study (to be verified in future quantitative researches) is that embryo donation could take place, for therapy of fertility, and exceptionally to research.

Allogeneic acute rejection on fetal small-bowel graft: role of gangliosides.

In previous work, it was shown that gangliosides (Gang) have an inhibitory effect on lymphocyte proliferation as well as on delayed-type hypersensitivity response and mixed lymphocyte reaction. Therefore, we decided to examine the effect of gangliosides in acute allorejection after fetal intestinal transplantation. We used two female C57BL/6 mice on pregnancy day 19 as a source of fetal intestine. All animals were anesthetized with ketamine (70 mg/kg) and xylazine (10 mg/kg), intramuscularly. We harvested intestinal segments of 1 cm to transplant into BALB/c and C57BL/6 mice (male, weighing around 20 g) used as recipients. They were divided into groups of six animals each: isogeneic and allogeneic without treatment, or treated with tacrolimus 1 mg/kg/day, or gangliosides 3 and 9 mg/kg/day, during 7 days posttransplantation, intramuscularly. On postoperative day 7, intestinal grafts were collected and fixed in 10% formalin solution. Using an anesthetic overdose as euthanasia, we removed the intestinal grafts. Tissue samples were stained with hematoxylin-eosin for histological analysis regarding grafts development (D) and rejection (R) aspects. Data were analyzed by the Kruskal-Wallis test, considering P < or = 0.05 as significant. In the isogeneic and tacrolimus groups, we observed a very good degree of development (D = 9 +/- 0.5; D = 9 +/- 0.4, respectively), but a severe degree of rejection (R = 15 +/- 1.3) and a low degree of development (D = 1 +/- 0.8) in animals without treatment. The ganglioside groups showed D = 5 +/- 1.6 and R = 13 +/- 3.3, and D = 7 +/- 2.9 and R = 9 +/- 1.9, for the 3-mg and 9-mg groups, respectively. There was a statistically significant difference between the ganglioside groups and allogeneic groups without treatment. Based on the above data, we conclude that avascular fetal intestine transplantation is a good experimental model for studying immunological events, and that gangliosides only partially modulate the allorejection response, allowing intestinal development, mainly at the highest ganglioside dose. Maybe immunomodulation would be better observed by using isolated types of gangliosides or association with other immunosuppressive drugs.

Murine fetal small-intestine grafts: morphometric and immunohistochemical evaluation.

We investigated histopathological changes following murine fetal intestinal transplantation. Fetal intestine, obtained from a pregnant C57BL/6 mouse, was transplanted into BALB/c and C57Bl/6 mice. Recipients were divided into three groups: isogeneic, and allogeneic treated with 3 mg/kg/day gangliosides (Allo-a) or 9 mg/kg/day (Allo-b). One week after transplant, all grafts showed good viability, confirmed by cellular mitosis in the mucosa and a well-defined propria muscular layer. Isogeneic grafts showed a thicker muscular layer than in the Allo-a (P = 0.02) and Allo-b (P = 0.004) groups. There was no difference in number of mitotic cells among groups. Goblet cells were significantly reduced in allografts treated with 3 mg gangliosides (P = 0.013) or 9 mg gangliosides (P = 0.002) compared to isografts. Villi height was similar in all studied groups. There was no difference in positivity of the enteric nervous system among groups. Atrophy was more common in the allogeneic groups, suggesting that isografts had better development than allografts treated with gangliosides. (

Trasplante de células progenitoras hematopoyéticas en pediatría: Una alternativa de tratamiento en inmunodeficiencias primarias / Hematopoietic stem cell transplant in combined immunodeficiency syndromes of childhood: An optimal treatment for primary immunodeficiency

The congenital immunodeficiency disorders in which the defect has been clearly traced to the stem cell can be cured with allogeneic stem-cell transplantation (SCT) from an unaffected donor. Widespread application of this treatment modality has been tempered by the fact that risk-benefit considerations do not always favor a procedure that carries a significant risk for morbidity and mortality. Some malignant disorders of childhood eventually have to be treated by an autologous or allogeneic SCT, however nonmalignant disorders can also be treated with this approach. This article reviews the current status of SCT for nonmalignant inherited immunodeficiency disorders.

Tradicionalmente el trasplante de células progenituras hematopoyéticas (TCPH) se ha utilizado en pacientes pediátricos para el tratamiento de padecimientos malignos. Sin embargo, también existen indicaciones y experiencia para padecimientos benignos dentro de los cuales se encuentran los síndromes de inmunodeficiencia combinada primaria. Estos síndromes de la infancia constituyen una serie de padecimientos que aun cuando son infrecuentes en la patología infantil constituyen un grupo de alteraciones que hasta hace más de tres décadas eran irremediablemente fatales. Con el advenimiento del TCPH el pronóstico de estos síndromes ha mejorado sustancialmente, por lo que es importante conocer sus resultados, así como su morbimortalidad asociada.

[Survival of dopaminergic neurons that were hibernated in vitro for seven days]. / Supervivencia in vitro de neuronas dopaminérgicas hibernadas durante siete días.

INTRODUCTION: The use of fresh foetal tissue in neurotransplants entails considerable problems of logistics that limit its clinical applicability, something that can be resolved by the development of optimal tissue storage procedures that do not affect in vivo viability and survival of dopamine. AIMS. To determine whether 7 days' hibernation affects the survival of mesencephalic tissue in vitro, and to compare it to fresh tissue. MATERIALS AND METHODS: The midbrains of rats were hibernated for 1, 3, 5 and 7 days at 4 degrees C. A cellular suspension was prepared for culture throughout a 7-day period. The number of TH+ cells present in the fresh and hibernated cultures was determined. RESULTS: The morphology of the hibernated and cultured dopaminergic neurons was very similar to that of the fresh cells. Comparing the viability of the hibernated and fresh cells did not reveal any significant differences. No significant differences between the numbers of TH+ neurons were observed at any of the hibernation times. The lowest rate of TH+ cell survival was reached at seven days' hibernation. Significant differences (p < 0.05) were found between the number of TH+ neurons for fresh and hibernated tissue. CONCLUSIONS: Hibernation at 4 degrees C for up to five days guarantees the survival of TH+ cells in vitro, but it is affected by longer times. This procedure could be considered useful for preserving human tissue in clinical transplant applications. These results refer to in vitro conditions; therefore, studies must be conducted to investigate the survival and functionality of hibernated and transplanted neurons in animal models to enable us to evaluate its applicability in neurorestorative therapy.

[Hematopoietic stem cell transplant in combined immunodeficiency syndromes of childhood: an optimal treatment for primary immunodeficiency]. / Trasplante de células progenitoras hematopoyéticas en pediatría: una alternativa de tratamiento en inmunodeficiencias primarias.

The congenital immunodeficiency disorders in which the defect has been clearly traced to the stem cell can be cured with allogeneic stem-cell transplantation (SCT) from an unaffected donor. Widespread application of this treatment modality has been tempered by the fact that risk-benefit considerations do not always favor a procedure that carries a significant risk for morbidity and mortality. Some malignant disorders of childhood eventually have to be treated by an autologous or allogeneic SCT, however nonmalignant disorders can also be treated with this approach. This article reviews the current status of SCT for nonmalignant inherited immunodeficiency disorders.

A bioética frente às situações emergentes: a esperança depositada em um cordão umbilical / Bioethics in Emerging Situations - Hope Deposited in an Umbilical Cord

A terapia celular carrega a promessa de se tornar a medicina do futuro, recuperando tecidos danificados ou mesmo eliminando a fila de transplantes. As células-tronco constituem um grupo celular que preserva a capacidade de auto-renovação, podendo diferenciar-se em tipos celulares diversos. A utilização de células-tronco de cordão umbilical, apesar de menos polêmica que as embrionárias, revela muitos aspectos de natureza moral e ética que emergem em relação aos bancos de armazenamento de uso autólogo e alogênico. Hoje, o uso da terapia celular ainda é bastante restrito e depende de um amplo desenvolvimento de pesquisas, contudo, uma grande esperança lhe é depositada. A Bioética é uma ferramenta para o delineamento de parâmetros éticos ao desenvolvimento tecno-científico. O presente estudo revelou que os limites e fronteiras de regulação de seu uso não estão claramente delineados e se mantém em constante transformação, percebendo-se uma clara tendência mundial no incentivo ao modelo alôgenico, a exemplo do Brasil e do Brasilcord. Em decorrência disso, o presente trabalho apresenta uma avaliação da utilização de células-tronco de cordão umbilical frente a visão da autonomia, da vulnerabilidade, da justiça, da equidade, da proteção, da precaução, da responsbilidade, da utilidade e da solidariedade.

Morphological changes on small-bowel fetal allografts in mice.

The aim of this study was to evaluate the early morphological development and acute rejection process in fetal intestine allografts. Grafts from C57BL/6 fetal intestines were implanted in an avascular form in BALB/C recipients. A syngeneic group of animals was used to compare the evolution. The allogeneic recipients were distributed in 6 groups, according to the day of sacrifice (3rd, 4th, 5th, 6th, 7th, and 10th postoperational day (POD)) and the control group on the 2nd, 5th, and 7th POD. These grafts were stained with hematoxylin and eosin for histological evaluation, in agreement with the classification of Auber et al. (Chirurgie 123:122-130, 1998). Data showed a progressive development of the graft until POD 5. On POD 3 and 4, a top grade of development and an initial rejection were observed. From POD 5-7 and on POD 10, the acute rejection reaction was more important than the development process. The higher level of rejection was observed on POD 10, and it was similar to the 7th POD. Our results showed good graft development until POD 5. After that, the acute rejection response impeded analysis of the development process.

Membrana amniótica no tratamento dos afinamentos corneais e esclerais / Amminiotic membrane in the treatment of corneal and scleral thinning

Objetivo: investigar a utilização da membrana amniótica como adjuvante no tratamento e restabelecimento de espessura dos afinamentos córneo-esclerais e epitelização corneal. Métodos: A membrana amniótica foi captada a partir de parto cesáreo e conservada em meio de preservação de córnea e glicerol 1:1 e conservada a - 80 graus centígrados. Sete olhos de 7 pacientes, sendo 4 portadores de afinamento corneal por afecções neurotróficas (Grupo 1: 2 herpes simples vírus; 1 após transplante de córnea; 1 por radioterapia) e 3 portadores de afinamento escleral após exerése de pterígio(Grupo 2: 2 com beta-terapia e 1 sem beta-terapia) foram submetidos à cirurgia para restabelecimento da superfície ocular e espessura córneo-escleral empregando membrana amniótica. Resultados: O tempo médio de seguimento foi de 12 meses (variação entre 11 meses e 15 meses). Um caso de úlcera neurotrófica secundária a radioterapia apresentou insucesso. Obtivemos sucesso do restabelecimento da superfície ocular e da espessura nos outros seis casos. Em relação à acuidade visual, 1 caso obteve melhora e os outros 6 permaneceram inalterados. A média de tempo de epitelização foi de 26,6 +/- 5,8 dias para o grupo 1 e 10,6 +/- 4,0 dias para o grupo 2. Conclusões: O uso de membrana amniótica constitui opção alternativa de grande utilidade na reconstrução da superfície ocular dos casos de afinamento córneo-escleral. Estudos com maior casuística e tempo de seguimento são necessários para melhor avaliar esse procedimento.

[Principles and juridical limits to human embryo research]. / Principios y límites jurídicos de la investigación con embriones humanos.

This work intends to provide a wide scope of the legal situation in Brazil referred to Human Embryos and how it has been developed through the 20th century. Across the last century, the human being got the possibility of making genetic experiments with human embryos. Our main goal is to assume the future responsibility of these actions through a juridical and ethical point of view.

An experimental model for the transplantation of fetal central nervous system cells to the injured spinal cord in rats

INTRODUCTION: Traumatic spinal cord injury is one of the most disabling conditions occurring in man and thus stimulates a strong interest in its histopathological, biochemical, and functional changes, primarily as we search for preventive and therapeutic methods. PURPOSE: To develop an experimental model for transplantation of cells from the fetal rat central nervous system to the site of an injured spinal cord of an adult rat in which the transplanted cells survive and become integrated. This experimental model will facilitate investigations of factors that promote regeneration and functional recovery after spinal cord trauma. MATERIAL AND METHODS: Fifteen adult Wistar rats underwent laminectomy, and an spinal cord lesion was made with microdissection. Fetal spinal cord tissue was then transplanted to the site of the injury. The rats were monitored over a 48-hour period, and then their vertebral column was completely removed for histological analysis. RESULTS: In 60 percent of transplanted rats, the fetal tissue at the injured site remained viable in the site of the lesion

Regeneration of natural antibody repertoire after massive ablation of lymphoid system: robust selection mechanisms preserve antigen binding specificities.

Natural Abs (NAbs) are Igs present in the serum and body fluids of healthy vertebrate animals, without any previous intentional immunization. NAbs often exhibit autoreactivity but also play an essential role in immunity, being a first line of defense against infectious microorganisms. We have previously analyzed the natural serum IgM Ab repertoire of normal mice, characterizing their reactivity with hundreds/thousands of self Ags; a significant similarity among different individuals was observed, and it was found that many reactivities of NAbs stably kept during adulthood were established early in life, implicating that period as a critical time window in the physiology of NAb repertoire selection. In the work reported here, experiments were conducted to address the role of normal lymphocyte ontogeny to the formation and stability of adult NAb repertoire. The massive destruction of the lymphoid system was promoted in adult mice with gamma-irradiation, and regeneration of hemopoietic tissues was granted by bone marrow or fetal liver inoculum. NAb repertoire regeneration was followed for 60 days after gamma-irradiation in bone marrow or fetal liver chimeric animals. The analysis of serum IgM reactivity with hundreds/thousands of self Ags showed that the NAb repertoire regenerated most of its original format after massive destruction of lymphoid compartments, characterizing autoreactive repertoire selection as a robust biological process. The data also show that regeneration of the NAb repertoire occurred similarly in fetal liver and bone marrow chimeras, although the latter animals poorly reconstituted their CD5(+) B1 cell compartment, suggesting that B1 cells are not essential for natural Ab regeneration.

[In vitro viability and glutathione levels in mesencephalic neurons after seven days hibernation]. / Viabilidad in vitro y niveles de glutati n en neuronas mesencef licas hibernadas durante siete d as.

In embryonic mesencephalic transplant in patients with Parkinson s disease dopaminergic survival is low (5 10%), and for this reason the use of multiple donors has been considered. The difficulty of obtaining more tissue determines the need for a procedure that enables human nigral tissue to be stored for a time without affecting its physiological state in any significant way. This study was designed to determine whether hibernation of tissue fragments has any influence on viability, how the viability of the mesencephalic cells behaves after 7 days hibernation and the glutathione levels in the hibernated tissue (HT). The viability of the HT in pieces (82.37 2.12) was found to be higher than the value for the whole mesencephalon (70.29 3.43). Viability of the HT, seven days at 4 C, at different post dissociation times, did not differ significantly. Despite the significant differences found between hibernated and fresh tissue at t= 0, this procedure does not seem to affect the mesencephalic tissue in any significant way, as it conserved a 94% viability after hibernation. No evidence was found of increased glutathione content as an antioxidizing response to the damage that might be caused by hibernation. These results suggest that since hibernation does not have any significant effect on the state of the cells it could be considered a useful procedure for conserving tissue to be used in clinical transplants. Moreover, further research is needed on survival and functionality of hibernated cells after being transplanted into animal models in order to evaluate their potential for use in cell therapy.