The role of apoptosis in the development of AGM hematopoietic stem cells revealed by Bcl-2 overexpression

Apoptosis is an essential process in embryonic tissue remodeling and adult tissue homeostasis. Within the adult hematopoietic system, it allows for tight regulation of hematopoietic cell subsets. Previously, it was shown that B-cell leukemia 2 (Bcl-2) overexpression in the adult increases the viability and activity of hematopoietic cells under normal and/or stressful conditions. However, a role for apoptosis in the embryonic hematopoietic system has not yet been established. Since the first hematopoietic stem cells (HSCs) are generated within the aortagonad-mesonephros (AGM; an actively remodeling tissue) region beginning at embryonic day 10.5, we examined this tissue for expression of apoptosis-related genes and ongoing apoptosis. Here, we show expression of several proapoptotic and antiapoptotic genes in the AGM. We also generated transgenic mice overexpressing Bcl-2 under the control of the transcriptional regulatory elements of the HSC marker stem cell antigen-1 (Sca-1), to test for the role of cell survival in the regulation of AGM HSCs. We provide evidence for increased numbers and viability of Sca-1(+) cells in the AGM and subdissected midgestation aortas, the site where HSCs are localized. Most important, our in vivo transplantation data show that Bcl-2 overexpression increases AGM and fetal liver HSC activity, strongly suggesting that apoptosis plays a role in HSC development

Embryonal subregion-derived stromal cell lines from novel temperature-sensitive SV40 T antigen transgenic mice support hematopoiesis

Throughout life, the hematopoietic system requires a supportive microenvironment that allows for the maintenance and differentiation of hematopoietic stem cells (HSC). To understand the cellular interactions and molecules that provide these functions, investigators have previously established stromal cell lines from the late gestational stage and adult murine hematopoietic microenvironments. However, the stromal cell microenvironment that supports the emergence, expansion and maintenance of HSCs during mid-gestational stages has been largely unexplored. Since several tissues within the mouse embryo are known to harbor HSCs (i.e. aortagonads-mesonephros, yolk sac, liver), we generated numerous stromal cell clones from these mid-gestational sites. Owing to the limited cell numbers, isolations were performed with tissues from transgenic embryos containing the ts SV40 Tag gene (tsA58) under the transcriptional control of constitutive and ubiquitously expressing promoters. We report here that the growth and cloning efficiency of embryonic cells (with the exception of the aorta) is increased in the presence of the tsA58 transgene. Furthermore, our results show that the large panel of stromal clones isolated from the different embryonal subregions exhibit heterogeneity in their ability to promote murine and human hematopoietic differentiation. Despite our findings of heterogeneity in hematopoietic growth factor gene expression profiles, high-level expression of some factors may influence hematopoietic differentiation. Interestingly, a few of these stromal clones express a recently described chordin-like protein, which is an inhibitor of bone morphogenic proteins and is preferentially expressed in cells of the mesenchymal lineage

Conservative treatment for whiplash (Cochrane Review).

BACKGROUND: Many treatments are available for whiplash-patients, but to date, no evidence exists for their effectiveness. OBJECTIVES: The objective of this systematic review was to assess the efficacy of conservative treatment in patients with whiplash-injuries (rated as Whiplash-Associated Disorders [WAD] I or II). SEARCH STRATEGY: A computerized literature search of Medline, Embase, Cinahl, Psychlit and the Cochrane Controlled Trial Register through June 1998 was carried out. We also screened reference lists of publications of identified randomized trials and relevant systematic reviews. SELECTION CRITERIA: Studies were selected for inclusion if they fit the following criteria: design was a (randomized) clinical trial (RCT); all patients had suffered a whiplash-injury; the type of intervention was a conservative one; pain, global perceived effect, or participation in daily activities was used as one of the outcome measures; and the publication was written in English, French, German or Dutch. DATA COLLECTION AND ANALYSIS: The methodological quality of the studies was independently assessed by two reviewers using the Maastricht-Amsterdam list. Three quality scores were calculated using this criteria list: the Overall methodological Quality Score, the Internal Validity Score and the Delphi Quality Score. The conclusion of the review was based on articles that scored a quality score of at least 50 percent of the maximum available score on two out of three quality scores. MAIN RESULTS: Eleven studies met the inclusion criteria. A broad variety of conservative interventions were evaluated, and only one study was performed in chronic whiplash patients. Only three studies satisfied at least 50 percent on two out of three quality scores indicating poor overall methodological quality. A high rank correlation was observed among the three methods of quality. Because of the heterogeneity of patient selection, interventions and outcome measures, no statistical pooling was performed. This review indicates that active treatments show a beneficial effect on at least one of the primary outcome measures, preferably pain. REVIEWER'S CONCLUSIONS: It appears that "Rest makes rusty." In other words, rest and immobilization using collars are not recommended for the treatment of whiplash, while active interventions, such as advice to 'maintain usual activities' might be effective in whiplash-patients. Nevertheless, caution is needed when attempting to draw conclusions regarding the efficacy of conservative treatments in whiplash-patients, because of the paucity of high-quality studies. No conclusions can be drawn about the most effective therapy for chronic whiplash-patients because only one low quality trial was identified

Conservative treatment for whiplash (Cochrane Review).

Item does not contain fulltextBACKGROUND: Many treatments are available for whiplash-patients, but to date, no evidence exists for their effectiveness. OBJECTIVES: The objective of this systematic review was to assess the efficacy of conservative treatment in patients with whiplash-injuries (rated as Whiplash-Associated Disorders [WAD] I or II). SEARCH STRATEGY: A computerized literature search of Medline, Embase, Cinahl, Psychlit and the Cochrane Controlled Trial Register through June 1998 was carried out. We also screened reference lists of publications of identified randomized trials and relevant systematic reviews. SELECTION CRITERIA: Studies were selected for inclusion if they fit the following criteria: design was a (randomized) clinical trial (RCT); all patients had suffered a whiplash-injury; the type of intervention was a conservative one; pain, global perceived effect, or participation in daily activities was used as one of the outcome measures; and the publication was written in English, French, German or Dutch. DATA COLLECTION AND ANALYSIS: The methodological quality of the studies was independently assessed by two reviewers using the Maastricht-Amsterdam list. Three quality scores were calculated using this criteria list: the Overall methodological Quality Score, the Internal Validity Score and the Delphi Quality Score. The conclusion of the review was based on articles that scored a quality score of at least 50 percent of the maximum available score on two out of three quality scores. MAIN RESULTS: Eleven studies met the inclusion criteria. A broad variety of conservative interventions were evaluated, and only one study was performed in chronic whiplash patients. Only three studies satisfied at least 50 percent on two out of three quality scores indicating poor overall methodological quality. A high rank correlation was observed among the three methods of quality. Because of the heterogeneity of patient selection, interventions and outcome measures, no statistical pooling was performed. This review indicates that active treatments show a beneficial effect on at least one of the primary outcome measures, preferably pain. REVIEWER'S CONCLUSIONS: It appears that "Rest makes rusty." In other words, rest and immobilization using collars are not recommended for the treatment of whiplash, while active interventions, such as advice to 'maintain usual activities' might be effective in whiplash-patients. Nevertheless, caution is needed when attempting to draw conclusions regarding the efficacy of conservative treatments in whiplash-patients, because of the paucity of high-quality studies. No conclusions can be drawn about the most effective therapy for chronic whiplash-patients because only one low quality trial was identified

Diagnosing inborn errors of lipid metabolism with proton nuclear magnetic resonance spectroscopy.

Contains fulltext : 50577.pdf (publisher's version ) (Closed access)BACKGROUND: Many severe diseases are caused by defects in lipid metabolism. As a result, patients often accumulate unusual lipids in their blood and tissues, and proper identification of these lipids is essential for correct diagnosis. In this study, we investigated the potential use of proton nuclear magnetic resonance (1H-NMR) spectroscopy to simultaneously identify and quantify (un)usual lipids present in the blood of patients with different inborn errors of lipid metabolism. METHODS: We extracted blood plasma or serum lipids in chloroform-methanol (2:1 by volume). After addition of the nonvolatile chemical shift and concentration reference compound octamethylcyclotetrasiloxane, we performed 1H-NMR measurements on a 500-MHz spectrometer. Assignments were based on the literature, computer simulations, and reference spectra of relevant authentic standards. RESULTS: Spectra of normal plasma samples allowed the identification of 9 lipid species. We found good correlation between conventional methods and 1H-NMR for cholesterol and triglyceride concentrations. We also investigated 4 inborn errors of lipid metabolism (3 in sterol metabolism and 1 in fatty acid metabolism). NMR analysis led to a correct diagnosis for all 4 diseases, whereas the concentration of the diagnostic metabolite could be determined for 3. CONCLUSIONS: 1H-NMR spectroscopy of blood plasma or serum lipid extracts can be used to accurately identify and quantify lipids. The method can also identify unusual lipids in the blood of patients with inborn errors of lipid metabolism. This technique may therefore be applicable in clinical diagnosis and follow-up

The efficacy of conservative treatment in patients with whiplash injury: a systematic review of clinical trials.

Item does not contain fulltextSTUDY DESIGN: A systematic review of the literature. OBJECTIVES: To assess the efficacy of conservative treatment in patients with whiplash injuries. SUMMARY OF BACKGROUND DATA: Many treatments are available for patients with whiplash injury, but there continues to be no evidence for their accepted use. METHODS: A computerized literature search of Medline, Embase, Cinahl, Psychlit, and the Cochrane Controlled Trial Register was performed. Studies were selected if the design was a (randomized) clinical trial; if all patients had sustained a whiplash injury; if the type of intervention was a conservative one; if pain, global perceived effect, and participation in daily activities were used as one of the outcome measures, and if the publication was written in English, French, German, or Dutch. The methodologic quality was independently assessed by two reviewers by using the Maastricht-Amsterdam list. Three quality scores were calculated using this criteria list: the Overall Methodologic Quality Score, the Internal Validity Score, and the Delphi Quality Score. The conclusion of the review was based on articles that scored a quality score of at least 50% of the maximum available score on two of three quality scores. RESULTS: Eleven studies met the inclusion criteria. Only three studies satisfied at least 50% on two of three ways of calculating a quality score, indicating overall poor methodology. There was a high rank correlation among the three ways of calculating a quality score. No statistical pooling was performed because of the heterogeneity of the interventions. This review indicates that active treatments show a beneficial long-term effect on at least one of the primary outcome measures. CONCLUSION: Caution is needed when drawing a valid conclusion on the efficacy of conservative treatments in patients with whiplash injury. It appears that "rest makes rusty," whereas active interventions have a tendency to be more effective in patients with whiplash injury