Spectrum of medulloblastomas demonstrated by computed tomography

Twenty-two patients with medulloblastomas were evaluated by computed tomography. Pretreatment evaluation in 13 patients has shown the various presentations of the tumor. Eighteen of the patients have had post-therapy computed tomographic studies. Computed tomography is sensitive in detecting residual and locally recurrent tumor as well as tumor seeding by cereborspinal fluid pathways. Computed tomography has proved to be valuable in patient management and in evaluating the effectiveness of various forms of treatment. The present group of medulloblastomas is compared to other pediatric posterior fossa tumors and differential diagnoses are discussed.     

Relationship of dialysis membrane and cause-specific mortality

A number of studies have suggested that type of dialysis membrane is associated with differences in long-term outcome of patients undergoing hemodialysis, both in terms of morbidity and mortality. The purpose of this study was to determine the relationship of membrane type and specific causes of death. Data from the United States Renal Data System Case Mix Adequacy Study, a national random sample of hemodialysis patients who were alive on December 31, 1990, were used. Our study was limited to patients in this data set who were undergoing dialysis for at least 1 year (n = 4,055). For the main analytic models, membrane type was classified into two categories: unmodified cellulose or MC/SYN (which combines modified cellulose [MC] and synthetic membranes [SYN]). The relationships of membrane type and major causes of mortality were analyzed using Cox proportional hazards models, which adjusted for multiple (21) covariates, including demographics, comorbidity, Kt/V, and other parameters. Patients were censored at transplantation or 60 days after a switch to peritoneal dialysis. Compared with patients dialyzed with unmodified cellulose membranes, the adjusted relative mortality risk (RR) from infection was 31% lower (RR = 0.69; P = 0.03) and from coronary artery disease was 26% lower (RR = 0.74; P = 0.07) for patients dialyzed with MC/SYN membranes. No statistically significant difference (all P > 0.1) was found in mortality risk from cerebrovascular disease (RR = 1.08), other cardiac causes (RR = 0.86), malignancy (RR = 0.90), or other known causes (RR = 0.82) between patients dialyzed with MC/SYN compared with unmodified cellulose membranes. These results offer support to reported experimental and observational clinical studies that have found that unmodified cellulose membranes may increase the risk for both infection and atherogenesis. Further studies are necessary to evaluate the possibility of confounding factors, compare more specific membrane types, and determine the pathophysiology linking membrane type to cause-specific mortality.     

Effect of modulators of erythropoiesis on the hemoglobinization of human erythroid cell cultures

A rapid spectrophotometric assay capable of detecting the hemoglobin content of 1000 mature erythrocytes has been utilized to quantitate the total hemoglobin synthesized by the progeny of circulating human erythroid progenitors in both the plasma clot and methylcellulose culture systems. The pronounced variation in the effect of different erythropoietin preparations on the hemoglobin content of cultured human peripheral blood bursts, previously described in a subjective manner, has been objectively quantitated. Further experiments demonstrated that both lymphocyte conditioned media and dexamethasone substantially increased the total hemoglobin synthesized by the progeny of cultured erythroid progenitors. The elevated amount of hemoglobin present in erythroid cultures containing either lymphocyte conditioned media and/or dexamethasone was due to both increased colony numbers and colony size. Assay of the total hemoglobin content per erythroid culture is an accurate, sensitive, measure of erythropoiesis in vitro and should be a valuable adjunct to the enumeration of BFU-E-derived erythroid colonies.     

Therapeutic angiogenesis with vascular endothelial growth factor in peripheral and coronary artery disease: a review

Therapeutic angiogenesis constitutes an alternative treatment for patients with extensive tissue ischaemia in whom primary vascular reconstruction procedures are not feasible or have previously failed. At present vascular endothelial growth factor (VEGF) has been the most widely used angiogenic factor in experimental and human clinical trials. Early clinical data provide evidence that gene transfer of the VEGF gene can achieve beneficial angiogenesis, with minimal side-effects. Ongoing phase III clinical studies will reveal definitive efficacy.     

Effects of transforming growth factor beta on the production of prostaglandin E and caseinase activity of unstimulated and interleukin 1-stimulated human articular chondrocytes in culture

Transforming growth factor beta (TGF beta) has previously been shown to have actions on chondrocytes and cartilage both in vitro and in vivo which suggest a role in connective tissue repair. In particular, some of its actions have been shown to be antagonistic to those of interleukin 1 (IL-1). In this study, the effects of TGF beta on prostaglandin E (PGE) production and caseinase activity, in the presence and absence of IL-1, in human articular chondrocytes were investigated. TGF beta 1 and TGF beta 2 were shown to modulate IL-1 beta-stimulated PGE production and caseinase activity. Both TGF beta 1 and beta 2 inhibited IL-1 beta-stimulated PGE production in the absence of serum and augmented it in the presence of serum. TGF beta 1 and TGF beta 2 inhibited IL-1-stimulated caseinase activity with and without serum. In general, the TGF beta s had little or no effect on basal PGE or caseinase levels. TGF beta s may be important modulators of chondrocyte metabolism, their effects on PGE production may depend on cytokine interactions; furthermore, their effects on caseinase activity may help prevent cartilage breakdown.      

Sugars and beyond. The role of sugars and the other nutrients and their potential impact on caries

The traditional concept of caries as a multifactorial transmittable and infectious disease has been challenged. Novel conceptual ideas have come to add to the complexity of this highly prevalent disease worldwide. Current etiological understanding of the disease has emphasized the pivotal role of sugars in caries. In fact, current definition points toward an ecological disease caused by the commensal microbiota that under ecological imbalances, mainly due to high and or frequent sugars consumption, creates a state of dysbiosis in the dental biofilm. This modern conceptual idea, however, tends to underrate a key issue. As humans are omnivore and consume a mix diet composed by a multitude of substances, the role of the diet in caries must not be restricted only to the presence of fermentable sugars. This review explores the contribution of other food components, ubiquitous to the diet, mostly as potentially protective factors. Anticaries nutrients might determine an environmental change, affecting the ecology of the oral microbiome and partially mitigating the effect of sugars. Understanding the function of the food usually consumed by the people will contribute new knowledge on the mechanisms associated with the onset of caries, on new caries risk variables and on potential novel strategies for the prevention and treatment of the disease.