Beware of effects on isotopes of dissolved oxygen during storage of natural iron-rich water samples: A technical note.

RATIONALE: Investigations of the isotope ratios of dissolved oxygen (δ18 ODO ) provide valuable information about the oxygen cycle in aquatic systems. However, oxidation of Fe(II) may change pristine δ18 ODO values during storage and can lead to a misinterpretation. We sampled an Fe(II)-rich spring system and measured δ18 ODO values at various time intervals in order to determine influences of Fe-oxidation. METHODS: Water samples were collected from an Fe-rich spring and related stream and the δ18 ODO values were measured in fresh, 4- and 13-day-old samples with an isotope ratio mass spectrometer. Three replicates were measured for each sample with a 1σ of ± 0.2‰. On-site parameters and Fe(II) contents were also measured over the course of the spring system by multi-parameter probes and spectrophotometry. RESULTS: The δ18 ODO values over the course of the spring system in fresh, 4- and 13-day-old samples revealed differences of up to 8‰. We explain this increase by the consumption of DO by Fe(II)-oxidation. After a flow length of 85 m the differences in δ18 ODO values between fresh and older samples decreased because most of the Fe(II) was consumed. CONCLUSIONS: False interpretations of δ18 ODO values are possible if Fe-rich water samples are measured after too long storage, and we recommend measurement immediately after sampling.

Impact of Hydrous Manganese and Ferric Oxides on the Behavior of Aqueous Rare Earth Elements (REE): Evidence from a Modeling Approach and Implication for the Sink of REE.

In this study, models were used for the first time to investigate the fate and transport of rare earth elements (REE) in the presence of hydrous manganese and ferric oxides in groundwaters from the coastal Bohai Bay (China). Results showed that REE sorption is strongly dependent on pH, as well as hydrous manganese and ferric oxide content. Higher proportions of REE were sorbed by hydrous manganese oxide as compared to hydrous ferric oxides, for example in the presence of neodymium. In this case, a mean 28% of this element was sorbed by hydrous manganese oxide, whereas an average 7% sorption was observed with hydrous ferric oxides. A contrasting REE sorption behavior was observed with hydrous manganese and ferric oxide for all investigated groundwaters. Specifically, REE bound to hydrous manganese oxides showed decreasing sorption patterns with increasing atomic number. The opposite trend was observed in the presence of hydrous ferric oxides. In addition, these results suggested that light REE (from La to Sm) rather than heavy REE (from Eu to Lu) are preferentially scavenged by hydrous manganese oxide. However, the heavy REE showed a greater affinity for hydrous ferric oxides compared to light REE. Therefore, both hydrous manganese and ferric oxide are important scavengers of REE. This study shows the implication of hydrous manganese and ferric oxide sorption for the sink of REE in groundwater.

Electronic cigarettes: The nicotyrine hypothesis.

There are conflicting reports about the efficacy of electronic cigarettes (e-cigs) as nicotine delivery devices and smoking cessation products. In addition, smokers' responses to some nicotine dependence questions often change as they transition to exclusive e-cig use. Nicotyrine may explain these observations. Nicotyrine forms by the gradual oxidation of nicotine in e-liquids exposed to air. E-cigs aerosolize nicotyrine along with nicotine. Nicotyrine inhibits the cytochrome P450 2A family of enzymes (CYP2A) in airways and liver. These enzymes metabolize nicotine to cotinine, and then cotinine to trans 3-hydroxycotinine. In humans, nicotine is metabolized primarily by hepatic CYP2A6. We propose that e-cig users (vapers) achieve measurable serum nicotine levels when they inhale nicotine and nicotyrine together, because nicotyrine reversibly inhibits nicotine metabolism by CYP2A13 in airways. Consuming nicotyrine by any route should irreversibly inhibit hepatic CYP2A6. When CYP2A6 is substantially inhibited, nicotine clearance is delayed and nicotine withdrawal symptoms are attenuated. Small, relatively infrequent nicotine doses can then sustain satisfying nicotine levels. This theory has numerous implications for e-cig research and tobacco control. Behavioral and pharmacokinetic e-cig studies should be interpreted with attention to likely levels of nicotyrine delivery: e-cig studies may need to routinely measure nicotyrine exposure, assess CYP2A6 activity, confirm nicotine delivery, or deliberately compare unoxidized and oxidized e-liquids. The risks of nicotyrine exposure include impaired clearance of all CYP2A substrates and any effects of the metabolic products of nicotyrine. CYP2A inhibitors like nicotyrine may be useful for future smoking cessation therapy.

On-Line Chemical Composition Analysis of Refillable Electronic Cigarette Aerosol-Measurement of Nicotine and Nicotyrine.

INTRODUCTION: Electronic cigarettes (e-cigs) generate aerosols that users inhale. Analyses of e-liquids inconsistently report nicotyrine, a nicotine analog that could impede nicotine metabolism, raising questions about nicotyrine formation. METHODS: E-cig aerosols were analyzed on-line using a Thermal Desorption Aerosol Gas Chromatograph. Three e-liquids were tested: an unflavored solution in propylene glycol (PG); an unflavored solution in PG and vegetable glycerin (VG), and a flavored solution in PG and VG. A heating duration experiment determined the nicotyrine to nicotine ratio (NNR) in particle phase as a function of the duration of e-cig activation. An aging experiment determined the NNR in e-liquids and aerosols as a function of time since initial exposure to air and storage condition. RESULTS: Nicotine and nicotyrine were quantified in all 3 e-liquids and aerosols. Duration of e-cig activation was inversely related to NNR (NNR = 0.04 with 3-s activation, 0.26 with 0.5 s). Aging influenced both e-liquid NNR and aerosol NNR. On average, the e-liquid NNR increased from 0.03 at 11 days after opening to 0.08 after 60 days. For similar heating durations, aerosol NNR increased from 0.05 at 11 days to 0.23 after 60 days. Storage conditions had little effect on NNR. CONCLUSIONS: E-cig aerosols have variable nicotyrine quantities. Aerosol NNR depends on vaping technique and time elapsed since the e-liquid was exposed to air. It is hypothesized that aerosolized nicotyrine could facilitate nicotine absorption, inhibit the metabolism of nicotine, and reduce a user's urge to smoke.

Modeling of rare earth element sorption to the Gram positive Bacillus subtilis bacteria surface.

In this study, rare earth element (REE) binding constants and site concentration on the Gram+ bacteria surfaces were quantified using a multi-site Langmuir isotherm model, along with a linear programming regression method (LPM), applied to fit experimental REE sorption data. This approach found one discrete REE binding site on the Gram+ Bacillus subtilis surface for the pH range of 2.5-4.5. Average log10 REE binding constants for a site j on these bacteria ranged from 1.08±0.04 to 1.40±0.04 for the light REE (LREE: La to Eu), and from 1.36±0.03 to 2.18±0.14 for the heavy REE (HREE: Gd to Lu) at the highest biomass concentration of 1.3 g/L of B. subtilis bacteria. Similar values were obtained for bacteria concentrations of 0.39 and 0.67 g/L indicating the independence of REE sorption constants on biomass concentration. Within the experimental pH range in this study, B. subtilis was shown to have a lower affinity for LREE (e.g. La, Ce, Pr, Nd) and a higher affinity for HREE (e.g. Tm, Yb, Lu) suggesting an enrichment of HREE on the surface of Gram+ bacteria. Total surface binding site concentrations of 6.73±0.06 to 5.67±0.06 and 5.53±0.07 to 4.54±0.03 mol/g of bacteria were observed for LREE and HREE respectively, with the exception of Y, which showed a total site concentration of 9.53±0.03, and a log K(REE,j) of 1.46±0.02 for a biomass content of 1.3 g/L. The difference in these values (e.g. a lower affinity and increased binding site concentration for LREE, and the contrary for the HREE) suggests a distinction between the LREE and HREE binding modes to the Gram+ bacteria reactive surface at low pH. This further implies that HREE may bind more than one monoprotic reactive group on the cell surface. A multisite Langmuir isotherm approach along with the LPM regression method, not requiring prior knowledge of the number or concentration of cell surface REE complexation sites, were able to distinguish between the sorption constant and binding site concentration patterns of LREE and HREE on the Gram+ B. subtilis surface. This approach quantified the enrichment of Tm, Yb and Lu on the bacteria surface and it has therefore proven to be a useful tool for the study of natural reactive sorbent materials controlling REE partitioning in the natural environment.

Open-pit coal-mining effects on rice paddy soil composition and metal bioavailability to Oryza sativa L. plants in Cam Pha, northeastern Vietnam.

This study quantified Cd, Pb, and Cu content, and the soil-plant transfer factors of these elements in rice paddies within Cam Pha, Quang Ninh province, northeastern Vietnam. The rice paddies are located at a distance of 2 km from the large Coc Sau open-pit coal mine. Electron microprobe analysis combined with backscattered electron imaging and energy-dispersive spectroscopy revealed a relatively high proportion of carbon particles rimmed by an iron sulfide mineral (probably pyrite) in the quartz-clay matrix of rice paddy soils at 20-30 cm depth. Bulk chemical analysis of these soils revealed the presence of Cd, Cu, and Pb at concentrations of 0.146±0.004, 23.3±0.1, and 23.5±0.1 mg/kg which exceeded calculated background concentrations of 0.006±0.004, 1.9±0.5, and 2.4±1.5 mg/kg respectively at one of the sites. Metals and metalloids in Cam Pha rice paddy soils, including As, Cd, Cr, Cu, Hg, Mn, Ni, Pb, and Zn, were found in concentrations ranging from 0.2±0.1 to 140±3 mg/kg, which were in close agreement with toxic metal contents in mine tailings and Coc Sau coal samples, suggesting mining operations as a major cause of paddy soil contamination. Native and model Oryza sativa L. rice plants were grown in the laboratory in a growth medium to which up to 1.5 mg/kg of paddy soil from Cam Pha was added to investigate the effects on plant growth. A decrease in growth by up to 60% with respect to a control sample was found for model plants, whereas a decrease of only 10% was observed for native (Nep cai hoa vang variety) rice plants. This result suggests an adaptation of native Cam Pha rice plants to toxic metals in the agricultural lands. The Cd, Cu, and Pb contents of the native rice plants from Cam Pha paddies exceeded permitted levels in foods. Cadmium and Pb were highest in the rice plant roots with concentrations of 0.84±0.02 and 7.7±0.3 mg/kg, suggesting an intake of these metals into the rice plant as shown, for example, by Cd and Pb concentrations of 0.09±0.01 and 0.10±0.04 mg/kg respectively in the rice grain endosperm. The adaptation of native rice plants, combined with bioaccumulation ratios of 1±0.6 to 1.4±0.7 calculated for Cd transfer to the rice grain endosperm, and maximum Cd transfer factors of 4.3±2.1 to the plant roots, strongly suggest a continuous input of some toxic metals from coal-mining operations to agricultural lands in the region of Cam Pha. In addition, our results imply a sustained absorption of metals by native rice plant varieties, which may lead to metal accumulation (e.g., Cd) in human organs and in turn to severe disease.

Proton-binding capacity of Staphylococcus aureus wall teichoic acid and its role in controlling autolysin activity.

Wall teichoic acid (WTA) or related polyanionic cell wall glycopolymers are produced by most gram-positive bacterial species and have been implicated in various cellular functions. WTA and the proton gradient across bacterial membranes are known to control the activity of autolysins but the molecular details of these interactions are poorly understood. We demonstrate that WTA contributes substantially to the proton-binding capacity of Staphylococcus aureus cell walls and controls autolysis largely via the major autolysin AtlA whose activity is known to decline at acidic pH values. Compounds that increase or decrease the activity of the respiratory chain, a main source of protons in the cell wall, modulated autolysis rates in WTA-producing cells but did not affect the augmented autolytic activity observed in a WTA-deficient mutant. We propose that WTA represents a cation-exchanger like mesh in the gram-positive cell envelopes that is required for creating a locally acidified milieu to govern the pH-dependent activity of autolysins.

Surface binding site analysis of Ca2+-homoionized clay-humic acid complexes.

Clay-humic substance complexes play a major role in controlling the mobility of toxic metals in contaminated soils. However, our understanding of the underlying mechanisms is limited. Binding site analysis of clay and clay-mineral-humic composites, in this study, revealed an enhanced surface reactivity for the clay surface by the sorbed humic substances. Kaolinite and illite had three binding sites with pK(a) values ranging from ∼4.5 to 9.6 at Ca(2+) concentrations of 0.01 and 0.1 M respectively. In the presence of peat humic acid (PHA), four or five binding sites were observed for humics sorbed kaolinite surface at Ca(2+) concentrations of 0.01 and 0.1 M respectively. pK(a) values ranged from ∼4.4 to 9.6 for humic acid concentration of 0.01 and 0.1 mg/mL. For illite, four or five binding sites were found with pK(a)s ranging from ∼4.1 to 9.4. From zeta potential measurements of PHA-kaolinite or PHA-illite suspensions, the already negative potential decreased by 30 mV from pH 4 to 7, and by 10 mV for pH values greater than 7. For illite the initial negative surface potential decreased by 15 mV up to a pH of 9. Above this pH, the potential decrease diminished to 2 or 5 mV. These changes in surface potential confirm the adsorption of PHA to the clay mineral surface. FTIR measurements of clay samples were able to identify the kaolinite and illite phases. In addition, FTIR absorption bands found in the range of 1950-1800 cm(-1), suggest the interaction of PHA with kaolinite and illite surfaces. The results of this study indicate that the sorption of humic substances increases the availability of clay surface functional groups for deprotonation and potential sorption of toxic metal cations.

Modeling lanthanide series binding sites on humic acid.

Lanthanide (Ln) binding to humic acid (HA) has been investigated by combining ultrafiltration and ICP-MS techniques. A Langmuir-sorption-isotherm metal-complexation model was used in conjunction with a linear programming method (LPM) to fit experimental data representing various experimental conditions both in HA/Ln ratio (varying between 5 and 20) and in pH range (from 2 to 10) with an ionic strength of 10(-3) mol L(-1). The LPM approach, not requiring prior knowledge of surface complexation parameters, was used to solve the existing discrepancies in LnHA binding constants and site densities. The application of the LPM to experimental data revealed the presence of two discrete metal binding sites at low humic acid concentrations (5 mg L(-1)), with log metal complexation constants (logK(S,j)) of 2.65+/-0.05 and 7.00 (depending on Ln). The corresponding site densities were 2.71+/-0.57x10(-8) and 0.58+/-0.32x10(-8) mol of Ln(3+)/mg of HA (depending on Ln). Total site densities of 3.28+/-0.28x10(-8), 4.99+/-0.02x10(-8), and 5.01+/-0.01x10(-8) mol mg(-1) were obtained by LPM for humic acid, for humic acid concentrations of 5, 10, and 20 mg L(-1), respectively. These results confirm that lanthanide binding occurs mainly at weak sites (i.e., ca. 80%) and second at strong sites (i.e., ca. 20%). The first group of discrete metal binding sites may be attributed to carboxylic groups (known to be the main binding sites of Ln in HA), and the second metal binding group to phenolic moieties. Moreover, this study evidences heterogeneity in the distribution of the binding sites among Ln. Eventually, the LPM approach produced feasible and reasonable results, but it was less sensitive to error and did not require an a priori assumption of the number and concentration of binding sites.

Surface charge and zeta-potential of metabolically active and dead cyanobacteria.

Zeta potential and acid-base titrations of active, inactivated, and dead Planktothrix sp. and Synechococcus sp. cyanobacteria were performed to determine the degree to which cell surface electric potential and proton/hydroxyl adsorption are controlled by metabolism or cell membrane structure. Surface OH(-) excess from potentiometric data, showed differences in surface charge between active and dead cyanobacteria from pH 3 to 10. Average zero salt effect pH (pH(pzse)) of 5.8+/-0.1 and 6.3+/-0.1 were obtained for active Planktothrix sp. and Synechococcus sp., respectively. Similarly for dead cyanobacteria pH(pzse) values of 5.8+/-0.1 and 4.6+/-0.1 were obtained. Zeta potentials of active Planktothrix sp. and Synechococcus sp. were positive at alkaline conditions, with a maximum of +13.7+/-1.5 mV at a pH of 9.0+/-0.1 for both species. This positive potential diminished in the presence of 1 mM HCO(-)(3). The zeta potential of Planktothrix sp. and Synechococcus sp. cells was negative at alkaline pH following their exposure to NaN(3), a metabolic inhibitor. The zeta potential of dead cyanobacteria was negative for Planktothrix sp., from pH 2.5 to 10.5, at -30 to -20 mV. Dead Synechococcus sp. exposed to a pH 2.5 solution recorded negative potentials to a minimum of -30 mV at pH 8, but positive potentials were found at higher pH reaching a maximum of +10 mV at pH 9.1. Zeta potentials for dead, but non-acidified Synechococcus sp. remained negative at -30 mV from an initial pH of 5.6 to 10.5, reflecting differences in cell wall structure between these species. These results indicate that Planktothrix sp. and Synechococcus sp. may metabolically control their surface charge to electrostatically attract bicarbonate anions at alkaline pH, required for photosynthesis.

Cadmium inhibits both intrinsic and extrinsic apoptotic pathways in renal mesangial cells.

Cadmium is a potent nephrotoxin that has been shown to induce apoptosis in some cells but also to prevent it under certain circumstances. In several clinical situations and experimental models of injury to the renal glomerulus, pathological proliferation of mesangial cells is followed by resolution involving mesangial cell apoptosis. We investigated the effects of Cd(2+) on rat mesangial cells induced to undergo apoptosis through either the extrinsic receptor-mediated pathway or the intrinsic mitochondrial-dependent pathway. Camptothecin initiated the intrinsic pathway with activation of caspase-9 and caspase-dependent cleavage of procaspase-3. Tumor necrosis factor-alpha (TNF-alpha) initiated caspase-8 activity and cleavage of pro-caspase-3 at the convergence point of the two pathways. However, pro-caspase-8 levels were low, and caspase-9 was also activated in response to TNF-alpha, characteristic of what have been termed type II cells. With both TNF-alpha and camptothecin, concurrent exposure to 10 microM CdCl(2) suppressed DNA laddering, nuclear condensation, and pro-caspase-3 cleavage. It also decreased activity of both caspase-8 and caspase-9, prevented caspase-8-dependent cleavage of the proapoptotic factor Bid, and suppressed release of cytochrome c from mitochondria. At this 10-microM concentration, Cd(2+) was unique among a number of metal ions in preventing DNA fragmentation. We conclude that Cd(2+) is anti-apoptotic in rat mesangial cells, acting by a mechanism that may involve general caspase inhibition. This may have consequences for the resolution of nephritis in situations of mesangial cell hyperproliferation.

Cadmium complexation by bacteriogenic iron oxides from a subterranean environment.

This study quantifies the metal sorption characteristics of subterranean bacteriogenic iron oxides (BIOS) and their organic phases (intermixed intact and fragmented bacteria). A Cd2+ ion-selective electrode was used to generate high-resolution metal sorption data as a function of increasing pH. A multisite Langmuir model, along with a linear programming regression method (LPM), was applied to fit experimental data. This approach found two discrete Cd2+ binding sites for the BIOS with average -log10 equilibrium constants (pK(S,j)) of 1.06 +/- 0.19 and 2.24 +/- 0.28. Three discrete sites were obtained for the bacterial fraction, with pK(S,j) values of -0.05 +/- 0.12, 1.18 +/- 0.02, and 3.81 +/- 0.16. This indicated that the BIOS surface had a lower affinity for Cd2+ than that of the bacteria. pK(S,j) values for the BIOS were similar to those reported for pure iron oxide phases, while the organic fraction pK(S,j) spectrum was consistent with previous spectra for intact bacteria. Individual binding site densities of 0.04 +/- 0.01 and 0.05 +/- 0.02 and 0.29 +/- 0.05, 0.11 +/- 0.01, and 0.09 +/- 0.02 micromol/mg of BIOS corresponded to the iron oxide mixture and bacteria fraction, respectively. These values indicated high concentrations of strong affinity Cd2+ complexing groups on the bacterial surface. Comparison of total site densities of 0.08 +/- 0.02 and 0.48 +/- 0.06 micromol/mg of BIOS for the mixture and the bacterial phase, respectively, suggested a nonadditive character for the BIOS surface reactivity. This was emphasized by a higher affinity for Cd2+, as well as an increase in total site concentration observed for the bacterial phase. LPM was able to distinguish between the BIOS mixture and its organic fraction Cd2+ complexation characteristics. This approach is therefore a useful tool for the study of natural sorbent materials controlling metal partitioning in contaminated and pristine environments.

Surface chemical heterogeneity of bacteriogenic iron oxides from a subterranean environment.

This study quantifies the surface chemical heterogeneity of bacteriogenic iron oxides (BIOS) and its end-members (2-line ferrihydrite and intermixed intact and fragmented bacteria). On a dry weight basis, BIOS consisted of 64.5 +/- 1.8% ferrihydrite and 34.5 +/- 1.8% organic matter. Enrichment of Al, Cu, Cr, Mn, Sr, and Zn was shown in the solid versus the aqueous phase (1.9 < log Kd < 4.2). Within the solid-phase Al (69.5%), Cu (78.7%), and Zn (77.9%) were associated with the bacteria, whereas Cr (59.8%), Mn (99.8%), and Sr (79.4%) preferred ferrihydrite. Acid-base titration data from the BIOS and bacteria were fitted using FOCUS pKa spectroscopy. The bacteria spectrum with pKa's of 4.18 +/- 0.37, 4.80 +/- 0.54, 6.98 +/- 0.45, and 9.75 +/- 0.68 was similar to discrete and continuous spectra for intact and fragmented bacteria. The BIOS spectrum recorded pKa's of 4.27 +/- 0.51, 6.61 +/- 0.51, 7.89 +/- 1.10, and 9.65 +/- 0.66 and was deconvoluted to remove overlapping binding site contributions from the bacteria. The resulting residual iron oxide spectrum coincided with discrete MUSIC spectra for goethite and lepidocrocite with pKa values of 4.10 +/- 0.43, 6.53 +/- 0.45, 7.81 +/- 0.76, and 9.51 +/- 0.68. Surface site density analysis showed that acidic sites (pKa < 6) were contributed by the bacteria (37%), whereas neutral sites (6 < pKa < 8) were characteristic of the iron oxide fraction (35%). Basic sites (8 < pKa) were higher in the bacteria (57%), than in the BIOS (44%) or iron oxide fractions (47%). This analysis suggested a high degree of bacterial group masking and a similarity between the BIOS and goethite surface reactivity. An understanding of the BIOS surface chemical heterogeneity and inherent proton and metal binding capacity was obtained through the use of FOCUS apparent pKa spectroscopy.

Determination of intrinsic bacterial surface acidity constants using a donnan shell model and a continuous pK(a) distribution method.

Intrinsic acidity constants (pK(a)(int)) for Bacillus subtilis (Gram+) and Escherichia coli (Gram-) cells were calculated from potentiometric titration data at different salt concentrations. Master curves were generated by replotting charge excess data as a function of pH(S) (pH at the location of surface reactive sites) where pH(S) was determined as a function of Donnan potential, Psi(DON). This potential decreased in magnitude with increasing ionic strength, from -48.5+/-0.2 to -3.5+/-0.0 mV for B. subtilis and -47.9+/-0.3 to -3.5+/-0.0 mV for E. coli at 0.01 and 0.5 M K(+), respectively, indicating an efficient surface charge neutralization by counterions. A fully optimized continuous (FOCUS) pK(a) distribution method revealed four binding sites on B. subtilis and E. coli surfaces from the master curves with pK(a)(int) values of 3.59+/-0.38, 4.33+/-0.57, 5.94+/-0.66, and 8.64+/-0.57 for B. subtilis and 3.73+/-0.44, 4.85+/-0.71, 6.56+/-0.64, and 8.79+/-0.62 for E. coli. These were assigned to functional groups according to reported pK(a) ranges of 2.0-6.0 (carboxylic acid), 3.2-3.5 (phosphodiesters), 5.6-7.2 (phosphoric acid), and 9.0-11.0 (amine groups). Average points of zero salt effect (pH(pzse)) for B. subtilis experiments were 6.63+/-0.21 and 6.42+/-0.08 as a function of pH(bulk) and pH(S), respectively. Under the same criteria, E. coli calculations yielded 5.73+/-0.23 and 5.45+/-0.05. An understanding of metal and proton reactivity on bacterial cell surfaces can be addressed quantitatively through the use of electrostatic and chemical equilibrium modeling techniques proposed in this study. The results are consistent with those of electrical force microscopy studies used to document the intrinsic electrochemical heterogeneity of bacterial cell surfaces.

Lipoma submucoso de colón / Submucous lipoma of the colon

Se presentan 4 casos de lipoma submucoso de colon. Dos de ellos de localización sigmoidea y dos cecoascendente. El dolor típico cólico, la hemoproctorragia y la mucorrea fueron los síntomas de presentación. La radiología con técnica de doble contraste y técnica de enema de agua y bajo kilovoltaje efectuó el diagnóstico en la totalidad de los casos. Todos fueron tratados mediante laparotomía exploradora. Tres mediante colotomía y extirpación y uno mediante hemicolectomia derecha. La describe la frecuencia, sintomatología, diagnóstico radiológico, anatomía patológica y tratamiento de estos raros tumores (AU)

Lipoma submucoso de colón / Submucous lipoma of the colon

Se presentan 4 casos de lipoma submucoso de colon. Dos de ellos de localización sigmoidea y dos cecoascendente. El dolor típico cólico, la hemoproctorragia y la mucorrea fueron los síntomas de presentación. La radiología con técnica de doble contraste y técnica de enema de agua y bajo kilovoltaje efectuó el diagnóstico en la totalidad de los casos. Todos fueron tratados mediante laparotomía exploradora. Tres mediante colotomía y extirpación y uno mediante hemicolectomia derecha. La describe la frecuencia, sintomatología, diagnóstico radiológico, anatomía patológica y tratamiento de estos raros tumores