Additional dose constraints for analytical beam weighting optimization in IMRT.

This work presents an improvement to an algorithm for analytical beam weighting optimization where a flexible objective function, which considers 'importance factors' for each anatomical region and 'allowed deviations' from the prescribed dose, is defined. This upgrading allows forcing the mean value of the dose distribution to be the desired value, by using Lagrange multipliers. A real case is presented to show the effect of this change.     

Genetics of ABO, H, Lewis, X and Related Antigens

The present knowledge on chemical, enzymatic, serologic and genetic aspects of ABH antigens is reviewed in an effort to produce a simple and coherent genetic model for the biosynthesis of these antigens and chemically related structures. The genetic control of type 1 (Le(a), Le(b), Le(c) and Le(d)), type 2 (X, Y, I, and H), type 3 and type 4 ABH and related antigens in different animal and human tissues is analyzed, taking into account the properties of the glycosyltransferases which are involved in their synthesis and considering possible competition for common acceptor and donor substrates. The phylogeny of ABH determinants shows that they appeared as tissular antigens much earlier than as red cell antigens. The ontogeny of ABH antigens suggests that they behave as differentiation antigens, and an effort is made to correlate their tissular distribution in the adult with the embryological origin of each tissue.     

Prevención de la enfermedad tromboembólica venosa en cirugía general

Postoperative venous thromboembolic disease (VTED) affects approximately one in four general surgery patients who do not receive preventive measures. In addition to the risk of pulmonary embolism, which is often fatal, patients with VTED may develop long-term complications such as post-thrombotic syndrome or chronic pulmonary hypertension. In addition, postoperative VTED is usually asymptomatic or produces clinical manifestations that are attributed to other processes and consequently this complication is often unnoticed by the surgeon who performed the procedure. Thus, the most effective strategy consists of effective prevention of VTED using the most appropriate prophylactic measures against the patient's thromboembolic risk. There is sufficient evidence that VTED can be prevented by pharmacological methods, especially heparin and its derivatives and with mechanical methods such as support tights or intermittent pneumatic compression of the lower extremities.To reduce the incidence of VTED as far as possible, strategies have been proposed that include a combination of drugs and mechanical methods, new antithrombotic drugs, or prolonging the duration of prophylaxis in patients at very high risk, such as those who have undergone surgery for cancer. Another important aspect is the optimal moment to initiate prophylaxis with anticoagulant drugs with the aim of achieving an adequate equilibrium between antithrombotic efficacy and the risk of hemorrhagic complications. The present article reviews the available evidence to attempt to optimize prevention of VTED in general surgery and in some special groups, such as laparoscopic surgery, short-stay surgery and obesity.     

Does bupivacaine in laparoscopic ports reduce postsurgery pain in tubal ligation by electrocoagulation? A randomized controlled trial

BackgroundTubal ligation (TL) is the most popular method of permanent contraception. In order to reduce postoperative pain, different analgesic techniques have been proposed. The objective of this study was to compare the level of postoperative pain in patients submitted to TL with electrocoagulation, under general anesthesia, using bupivacaine infiltration vs. placebo in trocar ports.Study DesignConsecutive patients scheduled for laparoscopic TL were randomized by sequenced coded envelopes to receive bupivacaine 0.5% (n=29) or placebo (n=24). Pain was blindly assessed at 15 min, 30 min, 120 min and 14 h postoperatively, by verbal analogue scale (VAS). Standard pain medications (morphine, dipyrone and sodium diclofenac) were prescribed for the subjects and compared between groups.ResultsNo difference in pain assessment was found between bupivacaine and placebo groups at all times [median (25–75 quartiles)] (all p>.05): 15 min: 3 (1–6.3) vs. 4 (0–7); 30 min: 1.5 (0–4.3) vs. 2 (0–5); 2 h: 0 (0–0.5) vs. 0 (0–1); 14 h: 1 (0–4) vs. 0 (0–4); and for use of analgesics: dipyrone (g): 1 (0–1) vs. 1 (0–1); morphine (mg): 3 (0–3) vs. 3 (0–3.5); sodium diclofenac (mg): 0 (0–50) vs. 0 (0–50).ConclusionThe use of local injection of bupivacaine 0.5% in the trocar ports was not superior to placebo to reduce pain after laparoscopic TL with electrocoagulation under general anesthesia.     

La integración de la cirugía y el tratamiento quimioterápico en el cáncer de vejiga infiltrante

IntroductionTreating patients with invasive transitional cell carcinoma of the bladder remains difficult due to the multiple biological behaviour patterns found in this disease. There is still controversy regarding the use of systemic treatment in invasive bladder carcinoma and the ideal moment for launching perioperative chemotherapy. We present an overview of current trends for systemic treatment of invasive bladder carcinoma.Material and methodsUsing MEDLINE, we reviewed relevant English and Spanish language literature published during the last five years, with “chemotherapy in bladder cancer” as keywords. We selected randomized trials, meta-analyses and clinical trials.ResultsWe obtained a total of 241 articles. Thirty-one of them referred to neoadjuvant and adjuvant chemotherapy in invasive bladder cancer. We classified the articles in three different groups neoadjuvant, adjuvant and neoadjuvant plus chemotherapy. All of that information is displayed in the tables within the text.ConclusionsA multidisciplinary approach to the treatment of invasive bladder cancer is essential to guarantee adequate oncological control. A detailed evaluation and proper selection of each patient is fundamental in determining the best moment to start chemotherapy.     

Ex vivo analysis of dialysis effluent-derived mesothelial cells as an approach to unveiling the mechanism of peritoneal membrane failure.

During peritoneal dialysis (PD), the peritoneum is exposed to bioincompatible dialysis fluids, which causes progressive fibrosis and angiogenesis and, ultimately, ultrafiltration failure. In addition, repeated episodes of peritonitis or hemoperitoneum may accelerate all these processes. Fibrosis has been classically considered the main cause of peritoneal membrane functional decline. However, in parallel with fibrosis, the peritoneum also displays increases in capillary number (angiogenesis) and vasculopathy in response to PD. Nowadays, there is emerging evidence pointing to peritoneal microvasculature as the main factor responsible for increased solute transport and ultrafiltration failure. However, the pathophysiologic mechanism(s) involved in starting and maintaining peritoneal fibrosis and angiogenesis remain(s) elusive. Peritoneal stromal fibroblasts have been considered (for many years) the cell type mainly involved in structural and functional alterations of the peritoneum; whereas mesothelial cells have been considered mere victims of peritoneal injury caused by PD. Recently, ex vivo cultures of effluent-derived mesothelial cells, in conjunction with immunohistochemical analysis of peritoneal biopsies from PD patients, have identified mesothelial cells as culprits, at least in part, in peritoneal membrane deterioration. This review discusses recent findings that suggest new peritoneal myofibroblastic cells may arise from local conversion of mesothelial cells by epithelial-to-mesenchymal transition during the repair responses that take place in PD. The transdifferentiated mesothelial cells may retain a permanent mesenchymal state, as long as initiating stimuli persist, and contribute to PD-induced fibrosis and angiogenesis, and hence to membrane failure. Future therapeutic interventions could be designated in order to prevent or reverse epithelial-to-mesenchymal transition of mesothelial cells, or its pernicious effects.     

Diagnosing insulin resistance by simple quantitative methods in subjects with normal glucose metabolism

OBJECTIVE: To identify a reliable yet simple indirect method for detection of insulin resistance (IR). RESEARCH DESIGN AND METHODS: A total of 65 subjects (44 men and 21 women aged 30-60 years) were selected by a simple random sampling method. Inclusion criteria were voluntary participation from staff and hospital personnel, absence of abnormal glucose tolerance, and normal results of lipid profile and basic blood chemistry. A blood sample was taken after a 12-h overnight fast to determine plasma lipid, glucose, and insulin levels. An intravenous glucose tolerance test with administration of insulin after 20 min and extraction of multiple blood samples for glucose and insulin measurements and calculation of the minimal model approximation of the metabolism of glucose (MMAMG) S(i) value were performed. Three indirect indexes used to predict insulin sensitivity or IR were calculated, and metabolic syndrome was diagnosed using the Adult Treatment Panel III (ATP III) criteria. All results were correlated with those of the MMAMG. RESULTS: The 75th percentile value as the cutoff point to define IR corresponded with a fasting plasma glucose level of 12 mU/l, a homeostasis model assessment of 2.6, a 25th percentile for S(i) value of 21, and QUICKI (quantitative insulin sensitivity check index) and McAuley indexes of 0.33 and 5.8, respectively. The S(i) index correlated (P < 0.001) with all the indirect indexes and parameters of the metabolic syndrome. CONCLUSIONS: When compared with the S(i) index, the most sensitive and specific indirect method was the score proposed by McAuley et al. (specificity 0.91, sensitivity 0.75, 9.2 probability ratio of a positive test), followed by the existence of metabolic syndrome (specificity 0.91, sensitivity 0.66, 7.8 probability ratio of a positive test).