The advantages of delayed imaging and radiographic correlation in scintigraphic localization of gastrointestinal bleeding

Two cases in which gastrointestinal bleeding was localized by serial scintigraphic imaging with red blood cells labeled in vivo with 99mTc-PYP are reported. The importance of both early serial imaging and delayed imaging and of the correlation with other radiographic techniques is demonstrated. Reflux of blood from the sigmoid into the proximal colon was observed in both cases. In one case, contrast material injected into a resected specimen confirmed the scintigraphic localization of the site of bleeding.     

Neuropsychological and linguistic follow-up studies of children with galactosaemia from an unscreened population

Many galactosaemics appear to have neuropsychological and/or linguistic problems in spite of dietary treatment. Because the neonatal screening program in Norway does not include galactosaemia, we have re-examined Norwegian galactosaemics. Of 16 known patients, 8 patients participated in the study. They had been diagnosed between 2 and 11 weeks of age, and were between 9 months and 19 years old at the time of this study. All had very low or 0 activity of galactose-1-phosphate uridyl transferase. As part of the study all were examined neurologically, and had an age-appropriate developmental/IQ test, an ABR and an EEG, and a comprehensive psycholinguistic evaluation. The three youngest patients had normal developmental/IQ tests, while the five older patients had IQ scores in or below low range of normal. The majority had delayed language development and three patients were classified as having verbal dyspraxia. ABR and EEG showed mild pathology in the oldest patient only. Galactosaemia appears to be associated with significant risks of developmental and language delays in this unscreened population.     

Extrachromosomal inheritance of susceptibility to trypanosome infection in tsetse flies. I. Selection of susceptible and refractory lines of Glossina morsitans morsitans

Differences in susceptibility to infection with Trypanosoma congolense between F1 families of Glossina morsitans morsitans indicated that susceptibility is maternally inherited in this species of tsetse fly. Twelve F1 families, six selected for susceptibility and six selected for refractoriness to infection, have been bred for up to 13 generations. The reciprocal differences demonstrated in the F1 generation persisted in these selected families over many generations, indicating that susceptibility/refractoriness to T. congolense infection is extrachromosomally inherited in G. m. morsitans. Repeated 'backcrossing' to males of the opposite strain showed that infection rates within families were independent of the contribution of the male parent. Susceptible families had a mean midgut infection rate of 76.9% and a mature (hypopharyngeal) infection rate of 47.9%. In the refractory families 88.9% of the flies failed to develop an infection, 11.1% had midgut infections and only 6.3% developed mature infections. Levels of midgut infection remained remarkably constant within families over generations, whether refractory or susceptible, while maturation rates varied between generations and between sexes. Males matured a significantly greater proportion of midgut infections than females in the susceptible families. It is suggested that the inheritance of susceptibility/refractoriness relates primarily to the establishment of midgut infections in G. m. morsitans, and that maturation of midgut infections is dependent upon environmental factors such as diet, and differences between sexes probably reflecting differences in rates of bloodmeal digestion.(ABSTRACT TRUNCATED AT 250 WORDS)     

Serum factors and the maturation ofTrypanosoma congolense infections inGlossina morsitans

Removal of certain components from pig or cow blood greatly reduces the maturation rate ofTrypanosoma congolense infections inGlossina morsitans fed on such diets. In particular, delipidation of serum has the same effect as complete removal of dietary serum with few midgut infections reaching maturity. The addition of gamma-globulin to red cells partially restores the ability of immature infections to transform suggesting that serum lipids or other serum factors are not acting directly on midgut trypanosome metabolism but indirectly through interactions between dietary constituents and the flies' metabolic processes. As susceptibility toT. congolense infection is known to be maternally inherited inG. morsitans, it is suggested that serum factors act through the flies' symbionts to induce maturation in midgut infections.     

Evidence of both ontogeny and transplant dose-regulated expansion of hematopoietic stem cells in vivo

Recent assessment of the long-term repopulating activity of defined subsets of hematopoietic cells has offered new insights into the characteristics of the transplantable stem cells of this system; however, as yet, there is very little known about mechanisms that regulate their self-renewal in vivo. We have now exploited the ability to quantitate these cells using the competitive repopulating unit (CRU) assay to identify the role of both intrinsic (ontological) and extrinsic (transplanted dose-related) variables that may contribute to the regulation of CRU recovery in vivo. Ly5.1 donor cells derived from day-14.5 fetal liver (FL) or the bone marrow (BM) of adult mice injected 4 days previously with 5-fluorouracil were transplanted at doses estimated to contain 10, 100, or 1,000 long-term CRU into irradiated congenic Ly5.2 adult recipient mice. Eight to 12 months after transplantation, there was a complete recovery of BM cellularity and in vitro clonogenic progenitor numbers and a nearly full recovery of day-12 colony-forming unit-spleen numbers irrespective of the number or origin of cells initially transplanted. In contrast, regeneration of Ly5.1+ donor-derived CRU was incomplete in all cases and was dependent on both the origin and dose of the transplant, with FL being markedly superior to that of adult BM. As a result, the final recovery of the adult marrow CRU compartment ranged from 15% to 62% and from 1% to 18% of the normal value in recipients of FL and adult BM transplantation, respectively, with an accompanying maximum CRU amplification of 150- fold for recipients of FL cells and 15-fold for recipients of adult BM cells. Interestingly, the extent of CRU expansion from either source was inversely related to the number of CRU transplanted. These data suggest that recovery of mature blood cell production in vivo may activate negative feedback regulatory mechanisms to prematurely limit stem cell self-renewal ability. Proviral integration analysis of mice receiving retrovirally transduced BM cells confirmed regeneration of totipotent lymphomyeloid repopulating cells and provided evidence for a greater than 300-fold clonal amplification of a single transduced stem cell. These results highlight the differential regenerative capacities of CRU from fetal and adult sources that likely reflect intrinsic, genetically defined determinants of CRU expansion but whose contribution to the magnitude of stem cell amplification ultimately obtained in vivo is also strongly influenced by the initial number of CRU transplanted. Such findings set the stage for attempts to enhance CRU regeneration by administration of agents that may enable full expression of regenerative potential or through the expression of intracellular gene products that may alter intrinsic regenerative capacity.