IMRT planning parameter optimization for spine stereotactic radiosurgery

Spine stereotactic radiosurgery (SSRS) is a noninvasive treatment for metastatic spine lesions. MD Anderson Cancer Center reports a quality assurance (QA) failure rate approaching 15% for SSRS cases, which we hypothesized is due to difficulties in accurately calculating dose resulting from a large number of small-area segments. Clinical plans typically use 9 beams with an average of 10 segments per beam and minimum segment area of 2-3 cm². The purpose of this study was to identify a set of intensity-modulated radiation therapy (IMRT) planning parameters that attempts to optimize the balance among QA passing rate, plan quality, dose calculation accuracy, and delivery time for SSRS plans. Using Pinnacle version 9.10, we evaluated the effects of 2 IMRT parameters: maximum number of segments and minimum segment area. Initial evaluation of the data revealed that 5 segments per beam along with minimum segment area of 4 cm² and 4 monitor units (MU) per segment (5-4-4 plans) was the most promising. IMRT QA was performed using a PTW OCTAVIUS 4D phantom with a 2D detector array. Our data showed no significant plan quality change with decreased number of segments and increased minimum segment area. The average coverage of GTV and CTV was 82.5 ± 13% (clinical) vs 82.5 ± 13% (5-4-4) and 92.3 ± 8% (clinical) vs 91.5 ± 8% (5-4-4). Maximum point dose to cord was 11.4 ± 3.5 Gy (clinical) vs 11.0 ± 4.0 Gy (5-4-4). Total plan delivery time was decreased by an average of 11.3% for the 5-4-4 plans. For IMRT QA, the gamma index passing rate (distance to agreement: 2.5 mm, local dose difference: 4%) for the original plans vs the 5-4-4 plans averaged 90.3% and 91.9%, respectively. In conclusion, IMRT parameters of 5 segments per beam and 4 cm² minimum segment areas provided a better balance of plan quality, delivery efficiency, and plan dose calculation accuracy for SSRS.     

Prognostic indexes in primary dilated cardiomyopathy

The purpose of this study was to investigate, if besides the hypocontractility, which is the main finding in Primary Cardiomyopathy (PDC) there was some other mechanism in the development of heart failure and if this fact could influence in it's prognosis. We studied 13 patients with PDC in the hemodynamic cardiac laboratory from January 1982 to January 1988, these with systemic arterial hypertension. Coronary heart disease, myocarditis, primary valvular lesion, infiltrative disease, nephropathy, congenital heart disease, diabetes and alcoholism, were excluded. The control group was formed by 12 healthy subjects, which were studied for another purpose. We analyzed nine variables, including ejection fraction, peripheral vascular resistance, systolic and diastolic circumferential stress, left ventricular mass, left ventricular end diastolic and systolic volumes as well as force-velocity and force-fiber length relationship. The patients were followed up from 8 to 60 months (average 39 months). The cases with PDC were divided in two groups, "compensated" and "decompensated". The last ones with low ejection fraction and significantly increases systolic stress. We investigated which was the mechanism of compensation and decompensation through the force-velocity and force-fiber length relation. We found that compensation is associated with great increase of the after-load forces, the more end systolic volume at the end of the systole is not only controlled by the "force", but the decompensation is developed when the hypocontractility is added to the incompetence to compensate the after load. We found that the three deaths in this study had these hemodynamic characteristics, being the cause of death: the presence of heart failure in two patients and ventricular fibrillation in one.(ABSTRACT TRUNCATED AT 250 WORDS)     

Non-insulin-dependent diabetes mellitus and hyperlipoproteinemia in patients with ischemic cardiopathy

Cardiovascular disease (CVD) constitutes the main cause of death in diabetes mellitus (DM): Previous studies at the "Instituto Nacional de Cardiología de México" have investigated the metabolic alterations of survivors of a myocardial infarction (MI), but none of them had focused on the metabolic profile of the diabetic patient. We compared two groups of patients with ischemic heart disease (IHD), one with (DMG) and one without (NDMG) Diabetes Mellitus, to investigate differences in the prevalence and nature of hyperlipoproteinemias (HLP) and other risk factors of atherosclerosis. DMG consisted of 117 patients (75 male, 42 female) and NDMG consisted of 119 patients (91 male y 28 female). (Female NDMG vs female DMG p less than 0.05). The presence of risks factors of atherosclerosis was investigated in all patients, and total cholesterol (chol) triglycerides (TG) and glucose were measured in post-absorptive phase. There were no differences regarding mean age (DMG: 60 +/- 8 years, NDM: 60 +/- 11 years), Quetelet Index (Kg./mt2: DMG: 26.5 +/- 3, NDMG: 26.7 +/- 3), TG: (DMG: 246.2 +/- 125, NDMG: 223.5 +/- 129) or Chol (DMG: 216 +/- 42 mg/dl, NDMG: 225 +/- 45 mg/dl). Hypertriglyceridemia was significantly higher in patients with DM, as a whole and when both sexes were studied separately (p less than 0.05). Hypercholesterolemia was significantly higher in NDMG (p less than 0.05) and without significance, in diabetic women. (p less than 0.05). Type IV phenotype was higher in DMG (p less than 0.05) whereas phenotypes IIa and IIa + IIb were more prevalent among non-diabetics (p less than 0.001, p less than 0.0001, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)     

National Immunization Commission: Strengthening evidence-based decision making in Argentina

In Argentina, the National Technical Advisory Group on Immunizations is represented by the National Immunization Commission (CoNaIn), an organization created by the Ministry of Health in 2000. Recently, the Argentine government has decided to prioritize vaccination as a state policy, emphasizing this strategy as a sign of social equity so CoNaIn was restructured to increase its capacity to formulate sound and evidence-based recommendations. The commission shall consist of a group of immunization experts, representatives of scientific societies, the immunization program and the Ministry of Health. Its functions include the formulation of recommendations on the introduction of vaccines into the immunization program. The recommendations are based on technical, programmatic and social criteria. This decision-making process transparent with the support and advice of experts and scientific societies and guided by available evidence decisions help strengthen the Ministry of Health immunization policy generating greater confidence and support from the population and health professionals.     

Chronic inflammatory demyelinating polyradiculoneuropathy in a boy with systemic lupus erythematosus

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is an acquired, autoimmune peripheral neuropathy. Systemic lupus erythematosus (SLE) is a multisystemic, autoimmune disease that can affect the central nervous system in about 40% of patients, with prevalence and incidence unknown in the pediatric population due to lack of multicenter studies. We report the case of a 13-year-old Mexican boy, diagnosed with CIDP at the onset of SLE, beginning with progressive muscle weakness of lower and upper limbs, without affection of the central nervous system. The patient had positive ANA, antiDNAdc, antiBeta2glycoprotein, anti-cardiolipin, ANCA-C and X. He received intravenous immunoglobulin, cyclophosphamide, steroids, and azathioprine and showed clinical improvement. It is important to take into account the presence of peripheral neurological disorders in patients with pediatric SLE, considering CIDP as an uncommon presentation, making the diagnosis important for better treatment and evolution.     

ANALYSIS OF THE ETHICAL ASPECTS OF PROFESSIONAL CONFIDENTIALITY IN DENTAL PRACTICE

From the point of view of deontological ethics, privacy is a moral right that patients are entitled to and it is bound to professional confidentiality. Otherwise, the information given by patients to health professionals would not be reliable and a trustable relationship could not be established. The aim of the present study was to assess, by means of questionnaires with open and closed questions, the awareness and attitudes of 100 dentists working in the city of Andradina, São Paulo State, Brazil, with respect to professional confidentiality in dental practice. Most dentists (91.43%) reported to have instructed their assistants on professional confidentiality. However, 44.29% of the interviewees showed to act contradictorily as reported talking about the clinical cases of their patients to their friends or spouses. The great majority of professionals (98.57%) believed that it is important to have classes on Ethics and Bioethics during graduation and, when asked about their knowledge of the penalties imposed for breach of professional confidentiality, only 48.57% of them declared to be aware of it. Only 28.57% of the interviewees affirmed to have exclusive access to the files; 67.14% reported that that files were also accessed by their secretary; 1.43% answered that their spouses also had access, and 2.86% did not answer. From the results of the present survey, it could be observed that, although dentists affirmed to be aware of professional confidentiality, their attitudes did not adhere to ethical and legal requirements. This stand of health professionals has contributed to violate professional ethics and the law itself, bringing problems both to the professional and to the patient.     

Immunogenicity and some safety features of a VEGF-based cancer therapeutic vaccine in rats,rabbits and non-human primates

We have developed a cancer vaccine candidate (hereafter denominated CIGB-247), based on recombinant modified human vascular endothelial growth factor (VEGF) as antigen, and the adjuvant VSSP (very small sized proteoliposomes of Neisseria meningitidis outer membrane). In mice, previous work of our group had shown that vaccination with CIGB-247 extended tumor-take time, slowed tumor growth, and increased animal survival. Immunization elicited anti-human and murine VEGF-neutralizing antibodies, and spleen cells of vaccinated mice are cytotoxic in vitro to tumor cells that produce VEGF.