Housing with females increases testosterone and cortisol levels in captive groups of black-handed spider monkeys (Ateles geoffroyi).

The black-handed spider monkey (Ateles geoffroyi) is a seasonal reproducer that requires a seclusiveness to copulate and has a fusion-fission social system. These features impose important restrictions to achieve reproduction of captive animals. We investigated if group composition in captive spider monkeys has any endocrine effects. We compared testosterone and cortisol concentrations during the mating season in all-male and multifemale-multimale groups to study if the former condition impairs reproductive potential and increases stress. Concentrations of testosterone and cortisol of males living with females were higher than those of all-male groups. In the multifemale-multimale condition, dominant males had the highest levels of testosterone, while the youngest males showed the highest concentrations of cortisol. Results show that males adjust well to isosexual grouping, this being an appropriate condition to keep animals when controlled reproduction is sought.

Abscesos renales y peri-renales: análisis de 44 casos / Renal and perinephric abscesses: a series of 44 cases

Renal abscesses are infrequent event and may occasionally be fatal. In order to characterize its main clinical features, its diagnosis and evolution, a retrospective-descriptive study was done with cases identified between 1996 and 2006 in a teaching hospital. Forty-four cases were collected (mean age 49.9 years). Diabetes mellitus was present in 38.6 percent, urinary calculi in 36.4 percent, and previous urinary tract infection in 11.4 percent of the studied population. Enterobacteriaceae were the most frequent isolated microorganisms (44.4 percent), and 33.3 percent had a poli-microbial culture in abscess samples. S. aureus was rarely identified. Main therapeutic approaches were minimally invasive procedures (pigtails, percutaneous drainage or nephrostomy) in 50 percent followed by surgical interventions (nephrectomy or surgical debridement) in ~30 percent. Only 20.5 percent of patients were treated exclusively by antibiotics. Minimally invasive procedures were applied progressively after 2001 (p < 0.005). In this series case-fatality rate was 4.5 percent; 13.6 percent (n = 6) developed septic shock. Nephrectomy was performed in 9 cases (20.5 percent). Patients selected for nephrostomy had a lower risk for ICU admission (Odds Ratio 0.083 IC95 0.008-0.911). Renal abscesses are cause of morbidity but had a low case-fatality ratio; the therapeutic approach has changed in recentyears favoring at present minimally invasive procedures.

Los abscesos renales son eventos infrecuentes pero potencialmente letales. Objetivo: Conocer sus características clínicas, diagnóstico y evolución. Metodología: Se efectuó un trabajo descriptivo-retrospectivo con los casos detectados entre 1996 y el 2006 en un centro universitario. Resultados: Se identificaron 44 pacientes (edad promedio 49,9 años) asociados en algunos casos a diabetes mellitus (38,6 por ciento), litiasis urinaria (36,4 por ciento) o infección urinaria previa (11,4 por ciento). Los microorganismos más frecuentes fueron Enterobacteriaceae (44,4 por ciento) y 33,3 por ciento> de los cultivos fueron polimicrobianos. Staphylococcus aureus se identificó infrecuentemente. La estrategia terapéutica principal fue el uso de técnicas mínimamente invasoras (pigtails, drenaje percutáneo o nefrostomía; 50 por ciento), y luego quirúrgicas (nefrectomía o aseos quirúrgicos; ~30 por ciento>). Sólo 20,5 por cientoo fue tratado exclusivamente con antimicrobianos. Los procedimientos mínimamente invasores se usaron en forma progresiva después del 2001 (p < 0,005). La letalidad en esta serie fue 4,5 por ciento> (n = 2) y 13,6 por ciento (n = 6) desarrolló shock séptico. La nefrectomía se aplicó en 9 casos (20,5 por ciento). Los pacientes seleccionados para nefrostomía tuvieron menos riesgo de ingresar a UCI (Odds Ratio 0,083 IC95 0,008-0,911). Conclusiones: Los abscesos renales son causa de morbilidad mayor aunque de baja letalidad. Su estrategia terapéutica ha ido cambiando en los últimos años a favor de procedimientos mínimamente invasores como los drenajes percutáneos y/o endoscópicos.

[The absence of brainstem reflexes does not predict short term mortality in anoxic ischemic coma]. / Coma anóxico-isquémico en 46 pacientes. Evolución a treinta días y su relación con los reflejos de tronco.

BACKGROUND: Anoxic-ischemic coma has a poor outcome with a high rate of mortality and morbidity. Therefore, clinical predictors of prognosis are needed for therapeutic decision-making. PATIENTS AND METHODS: Prospective analysis of 46 patients, 31 male, age range 19-85 years, with anoxic-ischemic coma following cardiac arrest. All the patients included in our study remained comatose with a Glasgow Coma Scale (GCS) score of six or less points, after their stabilization in the Intensive Care Unit. They were evaluated clinically using the pupillary light reflex, corneal reflex and vestibulo-ocular reflex testing, induced by caloric stimulation with cold water. Survival was evaluated using life tables. All patients were followed until the thirtieth day after the anoxic-ischemic event. RESULTS: Thirty five patients (76%) died within the next twenty-nine days, 8 patients (18%) reached the vegetative state, 2 patients (4%) achieved a recovery with disability, and only 1 patient (2%) was discharged without sequelae. One day, five and 30 days survival rates were 89, 53 and 29%, respectively. The abolition of all brainstem reflexes was not a predictor of mortality. CONCLUSION: Thirty day survival in this group of patients was 29% and the absence of brainstem reflexes was not a predictor of mortality.

Coma anóxico-isquémico en 46 pacientes: Evolución a treinta días y su relación con los reflejos de tronco / The absence of brainstem reflexes does not predict short term mortality in anoxic ischemic coma

Background: Anoxic-ischemic coma has a poor outcome with a high rate of mortality and morbidity. Therefore, clinical predictors of prognosis are needed for therapeutic decision-making. Patients and methods: Prospective analysis of 46 patients, 31 male, age range 19-85 years, with anoxic-ischemic coma following cardiac arrest. All the patients included in our study remained comatose with a Glasgow Coma Scale (GCS) score of six or less points, after their stabilization in the Intensive Care Unit. They were evaluated clinically using the pupillary light reflex, corneal reflex and vestibulo-ocular reflex testing, induced by caloric stimulation with cold water. Survival was evaluated using life tables. All patients were followed until the thirtieth day after the anoxic-ischemic event. Results: Thirty five patients (76%) died within the next twenty-nine days, 8 patients (18%) reached the vegetative state, 2 patients (4%) achieved a recovery with disability, and only 1 patient (2%) was discharged without sequelae. One day, five and 30 days survival rates were 89, 53 and 29%, respectively. The abolition of all brainstem reflexes was not a predictor of mortality. Conclusion: Thirty day survival in this group of patients was 29% and the absence of brainstem reflexes was not a predictor of mortality.

Laparoscopía en nefrectomías pediátricas / Laparoscopy in pediatric nephrectomy

La laparoscopía es una técnica quirúrgica que ha sido incorporada en la urología pediátrica en los últimos años. Se presenta como un procedimiento con ventajas respecto a la cirugía convencional, en relación con tiempo de estadía hospitalaria, dolor postoperatorio, estética y morbilidad. Presentar la casuística existente y resultados en nefrectomía laparoscópica en el Hospital Exequiel González Cortés, realizada entre los años 1997-2001. Se realizan 9 nefrectomías laparoscópicas, por vía transperitoneal o retroperitoneal. La distribución por sexo fue de 7 hombres y 2 mujeres, con un rango de edad entre 7 meses y 13 años, con un promedio de 52,2 meses. Se realizaron 9 nefrectomías por vía laparoscópica, 7 vía transperitoneal y 2 por vía retroperitoneal. 2 pacientes debieron ser convertidos al inicio de la serie clínica por inexperiencia (1 retroperitoneal y 1 transperitoneal). Los diagnósticos fueron: riñón multicístico (6), nefropatía por reflujo (1), obstrucción pieloureteral (1) y síndrome nefrótico corticorresistente (1). El tiempo quirúrgico promedio fue de 90 min (rango entre 30 y 240 min). No se describe dolor en el postoperatorio y el tiempo de estadía hospitalaria fue entre 1 y 8 días. No se registran complicaciones en el postoperatorio inmediato. La laparoscopía ha demostrado ser la primera alternativa para nefrectomía en la edad pediátrica, dado el bajo porcentaje de complicaciones reportadas, la menor estadía hospitalaria, mejor resultado estético y baja incidencia de dolor. Según nuestra experiencia, la técnica transperitoneal tiene ventajas comparativas en relación con la retroperitoneal, por presentar mejores reparos anatómicos, menor dificultad técnica y menor tiempo quirúrgico.

Pieloplastía videoasistida en obstrucción pieloureteral / Video assisted pyeloplasty in pyeloureteral obstruction

El objetivo de este trabajo es dar a conocer la experiencia en el manejo videoasistido de la OPU en la edad pediátrica en el Hospital Exequiel González C, presentándolo como una técnica novedosa con ventajas comparativas a la cirugía abierta y a la técnica laparoscópica intracorpórea. En el año 2001 se han realizado 7 pieloplastías videoasistidas, técnica en la cual la disección de la unión pieloureteral es por vía laparoscópica y su plastía se realiza en forma extracorpórea con técnica de Anderson-Hynes o de Fender. Todos los pacientes fueron varones con un rango de edad entre 7 meses y 8 años (promedio 31,3 meses). La pesquisa de estos pacientes fue mediante diagnóstico antenatal en 4 pacientes, infección urinaria en 1 y dolor cólico abdominal en 2. De los 7 pacientes intervenidos, en 6 se realizó pieloplastía de A-Hynes y en 1 la técnica de Fender. El tiempo operatorio promedio fue 76 min. (rango 55 a 120 min). En 6 pacientes se utilizó sonda Foley en el postoperatorio (promedio 4,3 días) y en todos se dejó drenaje en fosa lumbar. La analgesia y antibioticoterapia endovenosa se utilizó en promedio 48 h, manteniéndose terapia antibiótica oral hasta retiro de sonda uretrovesical. La estadía hospitalaria fluctuó entre 2 y 13 días, con un promedio de 5 días. El paciente en el cual se realizó la técnica de Fender cursó con íleo intestinal prolongado secundario afiltración de la sutura, evolucionando a largo plazo con reestenosis de la unión pieloureteral y compromiso moderado de la función renal ipsilateral; fue reintervenido por técnica abierta a los 5 meses del primer procedimiento. Esta técnica tiene ventajas en relación con la vía de abordaje tradicional en cuanto al mejor manejo del dolor y menor estadía hospitalaria. Además, tiene ventajas sobre la plastía intracorpórea por vía laparoscópica, dada su menor dificultad técnica.

Actividad rítmica espontánea en vasos de placenta humana: ¿un marcapaso fisiológico en los vasos sanguíneos? / Spontaneous rhythmic contractions of human umbilical vessels, evidences for a physiological pacemaker in blood vessels?

Background: Placental vessels are not innervated. Therefore the vasomotor activity and vascular tone is not regulated by the nervous system. Aim: To assess the existence of pacemaker mechanisms related to rhythmic motor activity of blood vessels. Material and methods: Isometric contractions of rings from umbilical and chorionic vessels of term human placentas were monitored. Results: Recordings of the circular layer of chorionic and umbilical vessels revealed rhythmic spontaneous contractions with a frequency of 1,4ñ0,05 cycles/min, the duration of each cycle was 42,8ñ0,24 s (n=12). The amplitude of contractions was larger in veins than in arteries, predominating in umbilical vein biopsies, proximal to the fetus. Both the frequency and the amplitude of contractions were relatively constant during the first 30 min. However, after an hour, the frequency declined while the amplitude increased. The absence of the endothelium neither modified the frequency nor the amplitude of the rhythmic activity. Blockage of voltage dependent sodium channels or calcium channels did not alter the frequency of spontaneous contractions, although their magnitude was reduced. Glibenclamide, an ATP-dependent K+ channel blocker or the blockade of gap junctions ablated the frequency and amplitude of spontaneous contractions. Conclusions: We propose that rhythmic contractions are triggered by pacemaker cells located in the circular layer of the smooth muscle of blood vessels and spread via gap junctions; they likely contribute to the control of blood flow

Enzymes from extremophiles.

The industrial application of enzymes that can withstand harsh conditions has greatly increased over the past decade. This is mainly a result of the discovery of novel enzymes from extremophilic microorganisms. Recent advances in the study of extremozymes point to the acceleration of this trend. In particular, enzymes from thermophilic organisms have found the most practical commercial use to date because of their overall inherent stability. This has also led to a greater understanding of stability factors involved in adaptation of these enzymes to their unusual environments.

Caracterización clínica de 450 pacientes con enfermedad cerebrovascular ingresados a un hospital público durante 1997 / Retrospective analysis of 450 patients with cerebrovascular disease admitted to a public hospital during 1997

Background: In Chile, cerebrovascular diseases are the fifth cause of death among men and the third cause among women. Aim: To assess the clinical features and management of patients with cerebrovascular disease admitted to a public hospital during 1997. Patients and methods: A retrospective analysis of clinical records of patients discharged with a diagnosis of cerebrovascular disease. Those records in which there was discordance between the discharge diagnosis and the clinical picture were not considered in the analysis. Results: Of the 563 discharges from the hospital with the diagnosis of cerebrovascular disease, 487 records were located and 450 were considered in the analysis. Fifty four percent of patients were male and ages ranged from 17 to 96 years old...

Implantation of bone marrow beneath the kidney capsule results in transfer not only of functional stroma but also of hematopoietic repopulating cells.

Renal ossicles are ossified structures developed after the implantation of a bone marrow (BM) plug beneath the kidney capsule. The authors have investigated the origin of the hematopoietic cells in murine renal ossicles by conducting sex-mismatched implants into Ly-5 congenic mice. BM plugs from transgenic mice provided additional genotypic tracers. Flow cytometry analyses on nonadherent cells from long-term cultures established with ossicles excised at 17 to 40 weeks postimplantation evidenced the presence of 5% to 70% of donor-derived myeloid cells. The genetic analysis of the day 12 colony-forming unit (CFU-S(12)) population in ossicles excised at 10 to 40 weeks postimplantation revealed that 16% to 93% of the colonies were of donor origin. Moreover, we describe for the first time the presence of long-term repopulating cells of donor origin in ossicles excised at 10 to 19 weeks postimplantation.

Insertion of enhanced green fluorescent protein into the lysozyme gene creates mice with green fluorescent granulocytes and macrophages.

Pluripotent hematopoietic stem cells have been studied extensively, but the events that occur during their differentiation remain largely uncharted. To develop a system that allows the differentiation of cultured multipotent progenitors by time-lapse fluorescence microscopy, myelomonocytic cells were labeled with green fluorescent protein (GFP) in vivo. This was achieved by knocking the enhanced GFP (EGFP) gene into the murine lysozyme M (lys) locus and using a targeting vector, which contains a neomycin resistant (neo) gene flanked by LoxP sites and "splinked" ends, to increase the frequency of homologous recombination. Analysis of the blood and bone marrow of the lys-EGFP mice revealed that most myelomonocytic cells, especially mature neutrophil granulocytes, were fluorescence-positive, while cells from other lineages were not. Removal of the neo gene through breeding of the mice with the Cre-deleter strain led to an increased fluorescence intensity. Mice with an inactivation of both copies of the lys gene developed normally and were fertile. (Blood. 2000;96:719-726)

Residual damage of lymphohematopoietic repopulating cells after irradiation of mice at different stages of development.

OBJECTIVE: The purpose of this study was to evaluate the repopulating properties of bone marrow (BM) from mice irradiated during embryonic and adult stages of development. MATERIALS AND METHODS: Four-day-old embryos, 17-day-old fetuses, and 12-week-old mice were irradiated with of 1 or 3 Gy of x-rays. At 3 and 9 months postirradiation, the effects generated within the different compartments of repopulating cells (RCs) were evaluated by determining, in a BM competition assay, the contribution of the irradiated precursors to the lymphohematopoiesis of recipients at different times posttransplantation (3, 9, and 15 months). RESULTS: The irradiation of 4-day-old embryos with either 1 or 3 Gy did not produce residual repopulation or differentiation effects within the different RCs assayed. However, significant impairments in RC functionality were observed in mice irradiated on the 17th day postconception or at the 12th week of age. Whereas irradiation of these animals with 1 Gy did not impair the long-term functionality of the very primitive 15-month-old RCs, irradiation with 3 Gy generated sustained impairment in all tested types of hematopoietic progenitors and RCs. Moreover, repopulation data derived from the analysis of recipient BM and thymus strongly suggested that the observed effects were produced within the multipotent pool of lymphohematopoietic RCs. CONCLUSIONS: Our data show the generation of long-term effects in the multipotent RCs of mice irradiated at fetal and adult stages of growth and reveals the normal functionality of the RCs from animals irradiated during the early stages of embryonic development.

Visualization of enzyme-catalyzed reactions using pH indicators: rapid screening of hydrolase libraries and estimation of the enantioselectivity.

The use of pH indicators to monitor hydrolase-catalyzed reactions is described. The formation of acid following an enzyme-mediated hydrolysis causes a drop in the pH that can be visualized by a change in the color of the indicator-containing solution. The best indicators are those showing a color transition within the operational pH range of the hydrolases, like bromothymol blue and phenol red. The enantioselectivity of lipases and esterases can be estimated using single isomers under the same conditions and comparing the color turnover for each one. The method has been tested to quickly evaluate the enantioselectivity of a lipase towards a set of ester substrates and applied to the hierarchical screening of a library of thermophilic esterases.

Synthesis of sialyl Lewis x mimetics as selectin inhibitors by enzymatic aldol condensation reactions.

Several D-mannosyl phosphate/phosphonate derivatives have been enzymatically prepared as sialyl Lewis x tetrasaccharide mimics, which showed strong-to-moderate inhibition against E-, P-, and L-selectins. The synthesis of these mimics is very straightforward; mannosyl aldehyde derivatives are condensed with dihydroxyacetone phosphate (DHAP) in the presence of a DHAP-dependent aldolase to provide mannosyl phosphates.

Restrictions in the stem cell function of murine bone marrow grafts after ex vivo expansion of short-term repopulating progenitors.

We investigated the in vivo implications associated with the ex vivo expansion of 5-fluorouracil (5-FU) preactivated murine bone marrow (BM) grafts. Analysis of cultures established with BM cells collected 2 and 4 days after 5-FU treatment (2d and 4d 5-FU BM, respectively) and stimulated with IL-3 + IL-6 and IL-3 + SCF resulted in the generation of samples highly enriched for colony-forming units granulocyte/macrophage (CFU-GMs). This result was best shown in cultures established with 4d 5-FU BM and incubated for 3 days with IL-3 + SCF; in these samples up to 10% of the cellularity consisted of CFU-GMs. Analyses of the spleen colony-forming unit (CFU-S)12/CFU-S8 ratio revealed a continuous decline in this parameter during the expansion process, suggesting a predominant differentiation stimulus in the cultures. Transplantation of BM grafts into myeloablated recipients revealed a marked improvement in the short-term radioprotection capacity (30 days survival) of ex vivo expanded BM, which was most significant in the case of 3-day expanded grafts. In contrast to this finding, progressive impairment of the long-term radioprotection capacity of the grafts was found to be associated with the expansion process. Irrespective of the type of ex vivo manipulation used, a predominantly lymphohematopoietic repopulation by donor cells was observed in all recipients analyzed in the long term (4-7 months) posttransplantation. To investigate more thoroughly whether the repopulation ability of the grafts was modified to some extent during the ex vivo expansion process, BM competition assays were performed. The data obtained at 30 and 120 days posttransplantation indicated that under the best conditions assayed (4d 5-FU BM expanded for 3 days with IL-3 + SCF) almost no change in the competitive repopulation ability of the grafts was produced. However, when analysis was delayed to 300 days posttransplantation, a twofold reduction in the stem cell function of the expanded grafts was noted. Based on this data it is proposed that, under our experimental conditions, a significant expansion in the number of short-term repopulating progenitors is produced concomitantly with a differentiation stimulus of the culture, which moderately restricts the number and/or the longevity of the self-renewing stem cells.

C2-symmetrical tetrahydroxyazepanes as inhibitors of glycosidases and HIV/FIV proteases.

C2-Symmetrical tetrahydroxyazepanes were synthesized as inhibitors for glycosidases. Tetrahydroxyazepane 1 is a non-specific inhibitor of various glycosidases, while compounds 2, 3 and 4 specifically inhibit beta-N-acetylglucosaminidase, beta-glucosidase, and alpha-fucosidase, respectively, with Ki in the micromolar range. Compound 1 is not an inhibitor of HIV/FIV proteases, but its 3,6-difluorobenzyl derivatives are moderate inhibitors of both enzymes.

Relevance of myeloablative conditioning in the engraftment of limiting numbers of normal and genetically marked lympho-hematopoietic stem cells.

We have studied the relevance of using myeloablative conditioning in the engraftment of limiting numbers of normal and retrovirally transduced bone marrow (BM) cells. The administration of high doses (10-12 Gy) of split-dose irradiation (4 h or 24 h intervals) to mice transplanted with small grafts (10(4)-10(6) cells) of normal BM not only minimized the endogenous reconstitution of recipients but also increased, with respect to single irradiation protocols, the survival rate of the animals in the long-term. The efficiency of these myeloablative regimens in BM transplantation protocols involving the use of transduced grafts was tested in mice transfused with 5 x 10(4)-2 x 10(6) genetically marked BM cells. Ninety percent of recipients survived in the long-term and, in most cases, predominant engraftment of the transduced population was apparent for up to 11 months post-transplantation. This was confirmed in hematopoietic samples corresponding to the CFU-S, the preCFU-S and the long-term repopulating cells of primary recipients. It was of significance, however, that reductions in the engraftment of the genetically marked cells were not associated with the engraftment of exogenous untransduced cells, but rather with rises in the extent of endogenous repopulation, revealing the difficulties of preventing the repopulation of residual endogenous stem cells when limiting numbers of transduced cells are transplanted. Our results emphasize the relevance of using efficient myeloablative conditioning regimens in those cases in which predominant and sustained engraftment of limiting numbers of transduced repopulating cells is required.

Granulocyte colony-stimulating factor mobilizes into peripheral blood the complete clonal repertoire of hematopoietic precursors residing in the bone marrow of mice.

We have established the clonal relationships between the hematopoietic precursors residing in the bone marrow (BM) and the peripheral blood (PB) of mice treated with granulocyte colony-stimulating factor (G-CSF). The use of animals whose hematopoiesis was reconstituted with genetically labeled stem cells has allowed us to show that an almost identical repertoire of clones is found in the colony-forming unit (CFU-S) population present in the BM and mobilized PB. Moreover, our data has shown that the frequency of expression of the repopulating clones in both types of CFU-S populations is the same, evidencing that G-CSF mobilized PB progenitor cells (PBPCs) closely reflect the clonal make-up of the hematopoietic precursors residing in the BM. When secondary recipients were transplanted with BM or mobilized PB grafts that had been harvested from the genetically marked mice, the presence of long-term lympho-hematopoietic repopulating clones was showed not only in the BM but also in the PB samples. No new clones were identified in the long-term repopulating cells of the mobilized animals with respect to those found in the CFU-S population. Moreover, the hematopoietic precursors that were capable of long-term reconstitution corresponded to the clones, which were most highly represented in the CFU-S compartment, suggesting, at least in the case of G-CSF treated mice, that the frequency of expression of the repopulating clones in the CFU-S population is prognostic for the clone longevity. Based on our experimental data, new advantages for the use of mobilized PBPCs in place of hematopoietic grafts procured from limited areas of BM are proposed.

Accelerated and long-term hematopoietic engraftment in mice transplanted with ex vivo expanded bone marrow.

Using a murine experimental model, we investigated whether ex vivo expansion of BM grafts under IL-3/IL-6 stimulation accelerates the early hematopoietic recovery of recipients of BM transplants. To facilitate the ex vivo expansion of hematopoietic progenitors, BM was first enriched in proliferatively active hematopoietic stem cells by a single treatment with 5-fluorouracil (5FU) 4 days prior to the BM harvest. The results showed that the number of CFU-GM and CFU-S12 progenitors in the graft was significantly increased (56-fold and 14-fold, respectively), as a result of a 3 day incubation in the presence of IL-3 and IL-6. Daily analysis of animals transplanted with 5 x 10(4) BM cells, either freshly harvested or expanded for 3 days, showed that the expanded grafts consistently allowed a faster hematopoietic recovery of recipients. Differences between both groups of transplanted animals were most evident when the number of either femoral or splenic CFU-GMs were compared, with increases close to 70-fold at the fifth day of engraftment being observed. Similarly, mice transplanted with expanded grafts showed a hastened recovery in the cellularity of both organs that was most significant during the second week following transplantation, with maximal increases of 15 and 40-fold in the BM and spleen, respectively. Differences in peripheral leukocyte numbers between both groups of recipients were much less remarkable than those observed in the hematopoietic organs, although from the nadir period to the 11th day post-transplantation differences ranging from twofold to sixfold were apparent, consistent with a higher rate of mouse survival.(ABSTRACT TRUNCATED AT 250 WORDS)