[Vertebral fractures: radiological diagnosis, differential diagnosis and prognostic implications]

Vertebral fractures are a relevant problem for the heavy clinical implications and carrying disability. Vertebral fractures can be traumatic or pathologic, the latter can be benign or malignant, both mostly frequent in the elderly. An initial approach to this issue can use plain radiographs, but the correct extension and evaluation must involve CT and MR imaging. In particular MR is a useful tool for the prognostic evaluation of spine marrow injuries and the differential diagnosis of osteoporotic and metastatic fractures.

Technical note: Detection of cat, dog, and rat or mouse tissues in food and animal feed using species-specific polymerase chain reaction

A PCR method based on the nucleotide sequence variation in the 12S ribosomal RNA, mitochondrial gene has been developed for the specific and qualitative detection and identification of cat, dog, and rat or mouse tissue in food and feedstuffs. The primers designed generated specific fragments of 108, 101, and 96 bp in length for cat, dog, and rat or mouse tissues, respectively. Specificity of the primers was tested against 32 nontarget species including mammals, birds, fish, and plant species. This PCR method allowed detection of raw and heated cat, dog, and rat or mouse tissues in meat/oats mixtures even when the concentration of the target species was reduced to 0.1%. Furthermore, the performance of the method was not affected by prolonged heat-treatment (up to 133 degrees C for 20 min at 300 kPa), and consequently, it could be very useful to verify the origin of raw materials in food and feedstuffs submitted to denaturing technologies, for which other methods cannot be applied.

Technical note: detection of chicken, turkey, duck, and goose tissues in feedstuffs using species-specific polymerase chain reaction

PCR method was applied for the qualitative identification of chicken (Gallus gallus), turkey (Meleagris gallipavo), duck (Anas platyrhynchos x Cairina muschata), and goose (Anser anser) tissues in feed-stuffs, on an individual basis. The assay uses oligonucleotide primers that are specific for each avian species, targeting the 12S rRNA mitochondrial gene. The primers designed generated amplicons of 95, 122, 64, and 98 bp length for chicken, turkey, duck, and goose, respectively. The specificity of the primers was tested against 29 animal species including mammals, birds, and fish, as well as 8 plant species. Analysis of experimental feedstuffs demonstrated the detection of each target species in the range of 0.1 to 100%. The performance of this method was not affected by prolonged heat-treatment (up to 133 degrees C for 20 min at 300 kPa), and consequently, it could be very useful for the accurate identification of tissues from these 4 avian species in products submitted to denaturing technologies, for which other methods cannot be applied.

Has evidence changed practice?: appropriateness of carotid endarterectomy after the clinical trials

OBJECTIVE

To assess how appropriateness of and indications for carotid endarterectomy (CEA) have changed following the publication of several large international randomized controlled trials (RCTs) designed to rationalize use of CEA.

METHODS

The New York Carotid Artery Surgery Study (NYCAS) is a population-based cohort study of all CEAs performed on elderly patients from January 1998 through June 1999 in New York State. Detailed clinical data were abstracted from medical charts to assess indications for and appropriateness of surgery using a list of 1,557 indications for CEA developed by national experts using RAND appropriateness methods. Deaths and strokes within 30 days of surgery were ascertained and confirmed by two physicians.

RESULTS

Among the 9,588 patients, the mean age was 74.6 years and 93.6% had 70 to 99% carotid stenosis. Nearly three-quarters of patients (72.3%) underwent CEA for asymptomatic stenosis, 18.6% for TIA, and 9.1% for stroke. Overall, 87.1% of operations were done for appropriate reasons, 4.3% for uncertain reasons, and 8.6% for inappropriate reasons (vs 32% inappropriate before the RCTs, p < 0.0001). Among procedures judged inappropriate, the most common reasons were high comorbidity in asymptomatic patients (62.2%), operating after a major stroke (14.2%), or for minimal stenosis (10.5%). Among asymptomatic patients, those with high comorbidity had over twice the risk of death or stroke compared to those without high comorbidity (7.13% vs 2.69%, p < 0.0001).

CONCLUSIONS

Since publication of the randomized controlled trials, there has been a reduction in the proportion of patients undergoing carotid endarterectomy (CEA) for inappropriate reasons. The shift toward many asymptomatic patients undergoing CEA is concerning because the net benefit from surgery for these patients is low and is reduced further for patients with high comorbidity.

Blood pressure early in diabetes depends on a balance between glomerular filtration rate and the renin-angiotensin system

Onset of diabetes increases plasma renin activity (PRA) and glomerular filtration rate (GFR), but blood pressure (BP) is normal. In this study, a 70% surgical reduction in kidney mass (RK) was used to decrease baseline GFR and to prevent hyperfiltration during diabetes, and angiotensin converting enzyme inhibitors (ACEI) were used to inhibit angiotensin II (AngII) production, to test the hypothesis that a balance between GFR and AngII is required for normal BP early in diabetes. Diabetes was induced with streptozotocin (STZ) (35 mg/kg intravenously); and after 7 days of hyperglycemia (range: 408 to 486 mg/dL), insulin was intravenously infused continuously for a 4-day normoglycemic recovery period. In normal kidney (NK) rats, diabetes increased PRA (2.4 +/- 0.6 to 4.6 +/- 0.5 ngAI/mL/h) and GFR (2.9 +/- 0.1 to 3.5 +/- 0.2 mL/min), and there was no change in mean arterial pressure (MAP) (89 +/- 1 v 91 +/- 1 mm Hg, measured 18 h/day). There was no change in either GFR or AngII during diabetes in RK+ACEI rats, and their MAP also did not change. Thus, the maintenance of normal MAP was accompanied by a balance between GFR and AngII in both of those groups. In NK+ACEI rats, however, GFR increased significantly with no change in AngII, and MAP decreased significantly during diabetes by approximately 8 mm Hg. In RK rats, PRA increased (0.5 +/- 0.1 to 2.6 +/- 0.5) but GFR did not increase, and MAP increased significantly by approximately 16 mm Hg. All rats were in sodium balance by day 4 of diabetes. These data support the hypothesis that normotension early in diabetes requires a balance between the increased AngII and GFR, and that BP will increase if AngII increases but GFR does not.

Conceptos actuales en la fisiopatología, monitorización y resolución del edema pulmonar

Pulmonary edema, both in its lesional as well as hydrostatic version, is a frequent cause of acute respiratory failure. From the pathophysiological point of view, the most important advance is undoubtedly the knowledge that the reabsorption process of pulmonary edema is an active process with energy consumption. This concept has revolutionized this field due to the possibility of finding substances or factors that stimulate or inhibit this reabsorption. Furthermore, in the monitoring field, significant advances have also been experimented due to the possibility of quantifying the edema in a simple and reliable way with transpulmonary thermodilution.

Greengenes, a chimera-checked 16S rRNA gene database and workbench compatible with ARB

A 16S rRNA gene database (http://greengenes.lbl.gov) addresses limitations of public repositories by providing chimera screening, standard alignment, and taxonomic classification using multiple published taxonomies. It was found that there is incongruent taxonomic nomenclature among curators even at the phylum level. Putative chimeras were identified in 3% of environmental sequences and in 0.2% of records derived from isolates. Environmental sequences were classified into 100 phylum-level lineages in the Archaea and Bacteria.

Greengenes, a chimera-checked 16S rRNA gene database and workbench compatible with ARB

A 16S rRNA gene database (http://greengenes.lbl.gov) addresses limitations of public repositories by providing chimera screening, standard alignment, and taxonomic classification using multiple published taxonomies. It was found that there is incongruent taxonomic nomenclature among curators even at the phylum level. Putative chimeras were identified in 3% of environmental sequences and in 0.2% of records derived from isolates. Environmental sequences were classified into 100 phylum-level lineages in the Archaea and Bacteria.

Greengenes, a Chimera-Checked 16S rRNA Gene Database and Workbench Compatible with ARB

A 16S rRNA gene database ( http://greengenes.lbl.gov ) addresses limitations of public repositories by providing chimera screening, standard alignment, and taxonomic classification using multiple published taxonomies. It was found that there is incongruent taxonomic nomenclature among curators even at the phylum level. Putative chimeras were identified in 3% of environmental sequences and in 0.2% of records derived from isolates. Environmental sequences were classified into 100 phylum-level lineages in the Archaea and Bacteria .

Apoptosis as a mechanism of natural resistance to HIV-1 infection in an exposed but uninfected population

BACKGROUND

Apoptosis, also known as programmed cell death, has been reported not only as a pathogenic mechanism, but also as a mechanism of resistance and control of a variety of infections. Particularly during HIV-1 infection, apoptosis is the main mechanism by which infected and uninfected CD4+ lymphocytes are eliminated. However, apoptosis as a mechanism of natural resistance to HIV infection has this far not been explored.

OBJECTIVE

To determine whether apoptosis could explain, at least in part, the natural resistance to HIV infection observed in some exposed but uninfected individuals (ESN).

RESULTS

Our data shows that peripheral blood monocytes in the ESN group has a predisposition to undergo spontaneous apoptosis, as well as apoptosis induced by HIV infection in vitro, compared with monocyte population from the control group at low risk of HIV infection.

CONCLUSIONS

These findings suggest that, in some ESN individuals, monocytes could play an important role in the control of HIV infection by undergoing apoptosis. However, since the variability among individuals is large, studies with larger cohorts focusing in monocyte apoptosis as pathogenic mechanisms are required.

Latin America's present and future challenges in toxicology education

Industrialization that Latin America has experienced during the past 50 years, the increase of population and the growth of chemical-related industries has generated a variety of environmental problems that must be addressed. After assessing these profound changes, greater emphasis should be placed on the study of environmental health and toxicology. Latin American countries face many problems that are common to other developing nations. Therefore, there is a demand for safety assessment and regulatory control of chemicals that create a need for increasing numbers of toxicologists. To meet this demand, educational programs in toxicology have to be designed. This paper utilizes a consultation questionnaire that includes toxicology-network members, scientists and educational institutions where toxicology is taught. An analysis of the information collected is made, with an emphasis on what we currently lack and on future challenges for toxicology professionals. Although the response from the study institutions was 65% (13 countries out of 20), the paper aims to assess the present situation of toxicology. The convenience for a certification/recognition for toxicologists is also evaluated. Action needs to be taken to promote scientific development based on regional specific needs that require increasing at the number of toxicology programs, and promoting of cooperation between academics and researchers. Among the limitations we have are the variability of curricula, objectives and priorities. The increasing globalization of markets and regulations requires the harmonization of graduate/postgraduate programs to ensure that risk assessment and management are dealt with uniformly. Cooperation among our countries and international assistance should play a more prominent role in the promotion of regional integration and the more efficient utilization of international experience in defining educational policies.

Human skin keratinocytes modified by a Friend-derived retroviral vector: a functional approach

The goal of this study was to test the efficiency and possible functional effects of a Friend Leukemia derived retrovirus vector (FOCH29-NeoR) on cultured human keratinocytes, obtained from skin biopsy samples. The keratinocytes were grown and infected with filtered Friend vector supernatant. After one or two doses of infection, one duplicate of the culture was submitted to selection with G418; the other one was utilized for DNA extraction and PCR modification detection. Transduction efficiency was 46.66 percent and 47.22 percent for one and two doses of infection respectively (range 100 to 15 %). Colony Forming Efficiency (CFE) assays were done with Rodhamine-B staining in nonselected modified cultures and negative controls. There was no difference in CFE (% CFE= 10.74+/-6.53 negative control vs % CFE= 9.22+/-5.45 with one dose, and % CFE= 10.03+/-5.74 with two doses of infection). Nevertheless, the cell-cycle analysis done by Propidium Iodade (PI) incorporation and colchicine-arrest assays in nonselected transduced and nontransduced cells show that transduced keratinocytes have a longer time to enter G2. As far as we know, this is the first report of retroviral transduction-induced changes in the cell cycle done on human keratinocytes. This observation is very important because retroviral vectors of genes, such as platelet derived growth factor (PDGF) or vascular endothelial growth factor (VEGF), are expected to facilitate the implementation of these modified cultures for tissue grafting and skin substitute development and potentiate the effectiveness of the grafts.