Native associations of early hematopoietic stem cells and stromal cells isolated in bone marrow cell aggregates

In suspensions of murine bone marrow, many stromal cells are tightly entwined with hematopoietic cells. These cellular aggregations appear to exist normally within the marrow. Previous studies showed that lymphocytes and stem cells adhered to stromal cells via vascular cell adhesion molecule 1 (VCAM1). Injection of anti-VCAM1 antibody into mice disrupts the aggregates, showing the importance of VCAM1 in the adhesion between stromal cells and hematopoietic cells in vivo. Early hematopoietic stem cells were shown to be enriched in aggregates by using a limiting-dilution culture assay. Myeloid progenitors responsive to WEHI-3CM in combination with stem cell factor (c-kit ligand) and B220- B-cell progenitors responsive to insulin-like growth factor-1 in combination with interleukin-7 are not enriched. We propose a scheme of stromal cell-hematopoietic cell interactions based on the cell types selectively retained within the aggregates. The existence of these aggregates as native elements of bone marrow organization presents a novel means to study in vivo stem cell-stromal cell interaction.     

Prevalencia del síndrome complejo de malnutrición e inflamación y su correlación con las hormonas tiroideas en pacientes en hemodiálisis crónica

Introduction

Low levels of thyroid hormones, total triiodothyronine (T3) and free triiodothyronine (FT3) in haemodialysis patients is a marker of malnutrition and inflammation and are predictors of mortality. The aim of this study was to determine the prevalence of malnutrition-inflammation complex syndrome in haemodialysis and its relationship with the thyroid hormones thyrotropin, T3, FT3 and free thyroxine (FT4), as well as to evaluate the prevalence of low FT3 syndrome and its correlation with nutritional and inflammatory markers.

Complete pathological response to Imatinib mesylate in an extraintestinal gastrointestinal stromal tumor

INTRODUCTION

Gastrointestinal stromal tumors (GIST) are the most frequent mesenchymal tumors of the digestive tract. Extraintestinal locations (EGIST) have been described showing similar pattern of immunohistochemical markers than GIST. Inhibitors of tyrosine kinases such as Imatinib or Sunitinib are the mainstay treatment in the management of advanced or metastatic GIST. Complete pathological response to these agents is an extremely rare event, especially in the case of EGIST due to its more aggressive behavior reported.

PRESENTATION OF CASE

Here we describe the case of a 61 years old woman, with an advanced GIST, who was operated after 10 months of Imatinib mesylate. The biopsy demonstrated the extra intestinal location of the tumor and a complete pathological response was confirmed.

DISCUSSION

Complete pathological response to Imatinib is a rare event. To our knowledge, this is the first report of complete response in an EGIST. New clinical, radiological and metabolic criteria of tumoral response to neoadjuvant treatment are revised.

CONCLUSION

EGIST complete pathological response to Imatinib can be achieved. However, recommendation of systematic neoadjuvant therapy with Imatinib remains investigational and more studies are warranted in the future.     

Surgical treatment of unstable pelvic fracture in children: Long term results

Paediatric pelvic fractures are rare lesions. In the literature still controversy exists regarding the management of these injuries. The sequelae of these types of lesions has been described. We report the management and long term outcome of 8 patients with paediatric pelvic fractures treated in our institution. Associated injuries to the Risser's growth nuclei are described that has not been previously reported. Anatomical reduction of the displaced fracture should be considered to minimise the risk of long term functional impairment.     

Gallbladder cancer: a morphological and molecular update

Gallbladder cancer (GBC) shows a marked geographical variation in its incidence, with the highest figures being seen in India and Chile and relatively low levels in many Western countries. Risk factors for its development include the presence of gallstones, infection and the presence of an anomalous pancreatobiliary ductal junction. It can arise from either a pathway involving metaplasia or dysplasia or one in which there is a pre-existing adenoma. The former is the more common and, because it is often not associated with a macroscopically recognizable lesion, leads to the recommendation that all gallbladders need to be examined microscopically. Accurate staging of invasive cancers is essential to determine prognosis and treatment, and this requires extensive tumour sampling. A number of genetic alterations have been identified in the preinvasive and invasive stages of GBC and they support the morphological evidence of there being two pathways by which tumours develop. Some of these genetic changes are associated with particular risk factors. For example, cases with anomalous pancreatobiliary ductal junction show a higher frequency of K-ras mutations. Some changes are associated with differences in prognosis. For example, cancers without expression of p21 but with expression for p27 have a better prognosis, whereas those that express c-erb-B2 have a worse one. Work has also been done on identifying clinical, imaging and other factors that indicate that patients have a higher risk of having GBC. This is particularly important in high-incidence areas in which GBC is a significant public health problem.     

Alterations in piglet small intestine after cholesterol deprivation

Mammalian cells require cholesterol for normal cell function. This requirement can be fulfilled by endogenous biosynthesis or by extracellular supplementation. Infants fed with human milk receive greater quantities of cholesterol than those fed commercial formulas. Whether this lack of cholesterol in commercial formulas poses a threat to normal neonatal cell function is not known. We compared small intestinal microvillus membrane fluidity, hydrolase activities, protein concentration, permeability to nonabsorbable markers, and weight gain in neonatal piglets receiving restricted intake of isocaloric formulas containing either normal amounts of cholesterol (145 mg/dl) or very low levels of cholesterol (less than 2 mg/dl). Using the fluorescent probe, diphenylhexatriene, and fluorescence polarization, microvillus membranes from cholesterol deprived piglets demonstrated higher fluidities than did microvillus membranes from animals fed normal concentrations of cholesterol. Cholesterol-deprived animals, even though their caloric intake was similar to cholesterol-fed animals, demonstrated a net weight loss per animal whereas the cholesterol-fed animals demonstrated a weight gain. These results demonstrate that in a pig model on a restricted intake, cholesterol deprivation alters the biophysical properties of the microvillus membrane.     

The gastroprotective effect of tannins extracted from duhat (Syzygium cumini Skeels) bark on HCl/ethanol induced gastric mucosal injury in Sprague-Dawley rats

The gastroprotective effect of quantified tannins (13.4%) from Syzygium cumini was determined. Gastric mucosal damage was induced in sixty eight rats by oral gavage administration of HCl/ethanol solution. For macroscopic and microscopic studies, 30 rats were divided into three groups consisting of a negative control, an Omeprazole group and a Tannins group. There was no significant difference in the number, size and surface area of macroscopic lesions between the three groups. Microscopic examination using Best's Ulcer Staging Index showed that Tannins had a very significant decrease in gastric mucosal damage with p<0.01. Average lymphocyte populations in the three groups showed no significant difference, although both the Tannins and Omeprazole group had fewer lymphocytes. Thirty-eight rats were studied for the amount of free radicals present after induction of gastric damage. A dose which consisted of 20.0 g tannins/kg rat weight showed significantly lower stomach free radical concentrations. These findings suggest that tannins extracted from S. cumini have gastroprotective and anti-ulcerogenic effects.