Influence of environmental factors on the tropical peatlands diazotrophic communities from the Southern Brazilian Atlantic Rain Forest.

The tropical peatlands of southern Brazil are essential for the maintenance of the Atlantic Rain Forest, one of the 25 hotspots of biodiversity in the world. Although diazotrophic micro-organisms are essential for the maintenance of this nitrogen limited ecosystem, so far studies have focused only on micro-organisms involved in the carbon cycle. In this work, peat samples were collected from three tropical peatland regions during dry and rainy seasons and their chemical and microbial characteristics were evaluated. Our results showed that the structure of the diazotrophic communities in the Brazilian tropical peatlands differs in the evaluated seasons. The abundance of the genus Bradyrhizobium showed to be affected by rainfall and peat pH. Despite the shifts of the nitrogen-fixing population in the tropical peatland caused by seasonality it showed to be constantly dominated by α-Proteobacteria followed by Cyanobacteria. In addition, more than 50% of nifH gene sequences have not been classified, indicating the necessity for more studies in tropical peatland, since the reduction of N supply in the peatlands stimulates the recalcitrant organic matter decomposition performed by peatland micro-organisms, influencing the C stock.

Saving the Male Breast: A Systematic Literature Review of Breast-Conservation Surgery for Male Breast Cancer.

BACKGROUND: Male breast cancer (MBC) management is extrapolated from female BC. Mastectomy remains the most frequently used surgical procedure for male breast cancer (MBC). We performed a literature review to assess the use of breast-conservation (BCS) in MBC as well as outcomes following BCS. METHODS: A systematic literature was performed, and articles screened to identify studies that measured overall survival (OS), disease-free survival (DFS), or local recurrence (LR) in patients undergoing BCS. Weighted averages based on study size were performed for LR, DFS, and 5-year OS. RESULTS: Eight studies met the inclusion criteria with male breast surgery cases, and 859 (14.7%) underwent BCS. The mean follow-up time was 53 months, and mean age was 62.6 years, with stage II as the most common presentation. Two studies reported that 50-71.4% of patients underwent sentinel lymph node biopsy, and four studies reported axillary lymph node dissection in 14.3-100%. Five studies reported on adjuvant radiation therapy in 12.0-100% of total patients undergoing BCS. Four studies reported use of hormonal therapy in 73.8-100% of patients. Four studies reported use of chemotherapy in 25-66.7% of patients. Seven studies reported LR among 116 patients, with a weighted average of 9.9%. Three studies reported on DFS in 14 patients, with a weighted average 85.6%. Two studies report OS in 143 patients with a weighted average of 84.4%. CONCLUSIONS: Breast conservation may be considered a safe alternative in the surgical treatment of MBC. Future research should focus on better standardization of local therapy for MBC and improved reporting of outcomes.

Microbial community and performance of slaughterhouse wastewater treatment filters.

The performance of anaerobic filter bioreactors (AFs) is influenced by the composition of the substrate, support medium, and the microbial species present in the sludge. In this study, the efficiency of a slaughterhouse effluent treatment using three AFs containing different support media was tested, and the microbial diversity was investigated by amplified ribosomal DNA restriction analysis and 16S rRNA gene sequencing. The physicochemical analysis of the AF systems tested suggested their feasibility, with rates of chemical oxygen demand removal of 72±8% in hydraulic retention times of 1 day. Analysis of pH, alkalinity, volatile acidity, total solids, total volatile solids, total Kjeldahl nitrogen, and the microbial community structures indicated high similarity among the three AFs. The composition of prokaryotic communities showed a prevalence of Proteobacteria (27.3%) and Bacteroidetes (18.4%) of the Bacteria domain and Methanomicrobiales (36.4%) and Methanosarcinales (35.3%) of the Archaea domain. Despite the high similarity of the microbial communities among the AFs, the reactor containing pieces of clay brick as a support medium presented the highest richness and diversity of bacterial and archaeal operational taxonomic units.

Matrix-assisted laser desorption ionization-time of flight mass spectrometry analysis of Escherichia coli categories.

The mass profiles of cell-free extracts of 180 commensal and pathogenic strains of Escherichia coli were determined by MALDI-TOF mass spectrometry (MS). While some peaks were highly conserved in all E. coli, several peaks occurred only in some strains, showing heterogeneity among them. We did not detect strain-specific peaks for any of the E. coli categories tested. However, review of the fully conserved and the variable peaks suggested that MALDI-TOF MS has the potential to distinguish commensal and uropathogenic E. coli strains. Additionally, eight Shigella sonnei isolates were tested and found to be indistinguishable from E. coli by MALDI-TOF MS under the test conditions.

Culture-independent analysis of endophytic bacterial communities associated with Brazilian sugarcane.

Sugarcane is an economically important culture in Brazil. Endophytic bacteria live inside plants, and can provide many benefits to the plant host. We analyzed the bacterial diversity of sugarcane cultivar RB-72454 by cultivation-independent techniques. Total DNA from sugarcane stems from a commercial plantation located in Paraná State was extracted. Partial 16S rRNA genes were amplified and sequenced for library construction. Of 152 sequences obtained, 52% were similar to 16S rRNA from Pseudomonas sp, and 35.5% to Enterobacter sp. The genera Pantoea, Serratia, Citrobacter, and Klebsiella were also represented. The endophytic communities in these sugarcane samples were dominated by the families Enterobacteriaceae and Pseudomonadaceae (class Gammaproteobacteria).

Prokaryotic communities of acidic peatlands from the southern Brazilian Atlantic Forest.

The acidic peatlands of southern Brazil are ecosystems essential for the maintenance of the Atlantic Forest, one of the 25 hot-spots of biodiversity in the world. In this work, we investigated the composition of prokaryotic communities in four histosols of three acidic peatland regions by constructing small-subunit (SSU) rRNA gene libraries and sequencing. SSU rRNA gene sequence analysis showed the prevalence of Acidobacteria (38.8%) and Proteobacteria (27.4%) of the Bacteria domain and Miscellaneous (58%) and Terrestrial (24%) groups of Crenarchaeota of the Archaea domain. As observed in other ecosystems, archaeal communities showed lower richness than bacterial communities. We also found a limited number of Euryarchaeota and of known methanotrophic bacteria in the clone libraries.

Influence of soil characteristics on the diversity of bacteria in the Southern Brazilian Atlantic Forest.

The Brazilian Atlantic Forest is one of the 25 biodiversity hot spots in the world. Although the diversity of its fauna and flora has been studied fairly well, little is known of its microbial communities. In this work, we analyzed the Atlantic Forest ecosystem to determine its bacterial biodiversity, using 16S rRNA gene sequencing, and correlated changes in deduced taxonomic profiles with the physicochemical characteristics of the soil. DNAs were purified from soil samples, and the 16S rRNA gene was amplified to construct libraries. Comparison of 754 independent 16S rRNA gene sequences from 10 soil samples collected along a transect in an altitude gradient showed the prevalence of Acidobacteria (63%), followed by Proteobacteria (25.2%), Gemmatimonadetes (1.6%), Actinobacteria (1.2%), Bacteroidetes (1%), Chloroflexi (0.66%), Nitrospira (0.4%), Planctomycetes (0.4%), Firmicutes (0.26%), and OP10 (0.13%). Forty-eight sequences (6.5%) represented unidentified bacteria. The Shannon diversity indices of the samples varied from 4.12 to 3.57, indicating that the soils have a high level of diversity. Statistical analysis showed that the bacterial diversity is influenced by factors such as altitude, Ca(2+)/Mg(2+) ratio, and Al(3+) and phosphorus content, which also affected the diversity within the same lineage. In the samples analyzed, pH had no significant impact on diversity.

Transition probabilities for the Au ((2)S, (2)D, and (2)P) with SiH(4) reaction.

Transition probabilities on the interaction of the ground and the lowest excited states of gold Au ((2)S:5d(10)6s(1), (2)D:5d(9)6s(2), and (2)P:5d(10)6p(1)) with silane (SiH(4)) are studied through ab initio Hartree-Fock self-consistent field calculations, where the atom's core is represented by relativistic effective core potentials. These calculations are followed by a multiconfigurational self-consistent field study. The correlation energy is accounted for through extensive variational and perturbative second order multireference Moller-Plesset configuration interaction analysis of selected perturbations obtained by iterative process calculations using the CIPSI program package. It is found that the Au atom in the ((2)P:5d(10)6p(1)) state inserts in the Si-H bond. In this interaction its corresponding D (2)A(') potential energy surface is initially attractive and only becomes repulsive after encountering an avoided crossing with the initially repulsive C (2)A(') surface linked to the Au((2)D:5d(9)6s(2))-SiH(4) fragments. The A, B, and C (2)A(') curves derived from the Au((2)D:5d(9)6s(2)) atom interaction with silane are initially repulsive, each one of them showing two avoided crossings, while the A (2)A(') curve goes sharply downwards until it meets the X (2)A(') curve interacting adiabatically, which is linked with the Au((2)S:5d(10)6s(1))-SiH(4) moieties. The A (2)A(') curve becomes repulsive after the avoided crossing with the X (2)A('), curve. The lowest-lying X (2)A(') potential leads to the HAuSiH(3) X (2)A(') intermediate molecule. This intermediate molecule, diabatically correlated with the Au((2)P:5d(10)6p(1))+SiH(4) system which lies 3.34 kcal/mol above the ground state reactants, has been carefully characterized as have the dissociation channels leading to the AuH+SiH(3) and H+AuSiH(3) products. These products are reached from the HAuSiH(3) intermediate without any activation barrier. The Au-SiH(4) calculation results are successfully compared to experiment. Landau-Zener theory of avoided crossings is applied to these interactions considering the angle theta instead of the distance r as the reaction coordinate.

Chemical composition of lipopolysaccharides isolated from various endophytic nitrogen-fixing bacteria of the genus Herbaspirillum.

Bacteria from the genus Herbaspirillum are endophytes responsible for nitrogen fixation in gramineous plants of economic importance such as maize, sugarcane, sorghum, rice, and wheat. Some species are known to produce plant growth substances. In contrast, Herbaspirillum rubrisubalbicans strains are known to be mild plant pathogens. The molecular communication between the plant and the microbes might involve lipopolysaccharides present in the outer membrane of these gram-negative bacteria. Phenol-water extraction was used to obtain lipopolysaccharides from 7 strains of Herbaspirillum seropedicae (SmR1, Z67, Z78, ZA95, and M2) and H. rubrisubalbicans (M1 and M4). The electrophoretic profiles and chemical composition of the lipopolysaccharides obtained in the phenol and aqueous extracts were shown herein.

Diversity of endophytic bacteria in Brazilian sugarcane.

Endophytic bacteria live inside plant tissues without causing disease. Studies of endophytes in sugarcane have focused on the isolation of diazotrophic bacteria. We examined the diversity of endophytic bacteria in the internal tissues of sugarcane stems and leaves, using molecular and biochemical methods. Potato-agar medium was used to cultivate the endophytes; 32 isolates were selected for analysis. DNA was extracted and the 16S rRNA gene was partially sequenced and used for molecular identification. Gram staining, catalase and oxidase tests, and the API-20E system were used to characterize the isolates. The strains were divided into five groups, based on the 16S rRNA sequences. Group I comprised 14 representatives of the Enterobacteriaceae; group II was composed of Bacilli; group III contained one representative, Curtobacterium sp; group IV contained representatives of the Pseudomonadaceae family, and group V had one isolate with an uncultured bacterium. Four isolates were able to reduce acetylene to ethylene. Most of the bacteria isolated from the sugarcane stem and leaf tissues belonged to Enterobacteriaceae and Pseudomonaceae, respectively, demonstrating niche specificity. Overall, we found the endophytic bacteria in sugarcane to be more diverse than previously reported.

Environmental isolation of black yeast-like fungi involved in human infection.

The present study focuses on potential agents of chromoblastomycosis and other endemic diseases in the state of Paraná, Southern Brazil. Using a highly selective protocol for chaetothyrialean black yeasts and relatives, environmental samples from the living area of symptomatic patients were analysed. Additional strains were isolated from creosote-treated wood and hydrocarbon-polluted environments, as such polluted sites have been supposed to enhance black yeast prevalence. Isolates showed morphologies compatible with the traditional etiological agents of chromoblastomycosis, e.g. Fonsecaea pedrosoi and Phialophora verrucosa, and of agents of subcutaneous or systemic infections like Cladophialophora bantiana and Exophiala jeanselmei. Some agents of mild disease were indeed encountered. However, molecular analysis proved that most environmental strains differed from known etiologic agents of pronounced disease syndromes: they belonged to the same order, but mostly were undescribed species. Agents of chromoblastomycosis and systemic disease thus far are prevalent on the human host. The hydrocarbon-polluted environments yielded yet another spectrum of chaetothyrialean fungi. These observations are of great relevance because they allow us to distinguish between categories of opportunists, indicating possible differences in pathogenicity and virulence.

Topical anesthesia versus sub-Tenon block for cataract surgery: surgical conditions and patient satisfaction.

PURPOSE: To compare the surgical conditions and complications and patient and surgeon satisfaction in cataract surgery by phacoemulsification under topical anesthesia (TA) versus sub-Tenon block (STB). METHODS: Prospective randomized comparative blind study, without placebo control. Patient satisfaction evaluated by the Iowa Satisfaction with Anesthesia Scale (ISAS). RESULTS: The authors prospectively enrolled 59 patients (61% female) in the study, who were randomized into groups: 26 in the TA group and 33 in the STB. There was no statistically significant difference between the groups in terms of age, sex, waiting time for surgery, ASA (American Society of Anesthesiologists) state, eye laterality, cataract density, pupillary dilation, or surgery duration, but patient collaboration was better in the STB group. We found a mean 2.2 mmHg post-anesthetic rise in intraocular pressure in the STB group, with normalization at 24 hours, and no rise in the TA group. Subconjunctival hemorrhage and chemosis were more prevalent in the STB group, and the improvement of visual acuity was similar in both groups. Subjective satisfaction with the anesthetic technique, both for the surgeon and for the patient, was more elevated in the STB group. The final ISAS scores were 1.87 in the TA group and 2.71 in the STB (p<0.005). CONCLUSIONS: The data indicate that more significant anesthesia and analgesia was achieved with the STB, leading to more favorable surgical conditions and enhanced patient and surgeon satisfaction.

A simple and efficient method for poly-3-hydroxybutyrate quantification in diazotrophic bacteria within 5 minutes using flow cytometry.

The conventional method for quantification of polyhydroxyalkanoates based on whole-cell methanolysis and gas chromatography (GC) is laborious and time-consuming. In this work, a method based on flow cytometry of Nile red stained bacterial cells was established to quantify poly-3-hydroxybutyrate (PHB) production by the diazotrophic and plant-associated bacteria, Herbaspirillum seropedicae and Azospirillum brasilense. The method consists of three steps: i) cell permeabilization, ii) Nile red staining, and iii) analysis by flow cytometry. The method was optimized step-by-step and can be carried out in less than 5 min. The final results indicated a high correlation coefficient (R2=0.99) compared to a standard method based on methanolysis and GC. This method was successfully applied to the quantification of PHB in epiphytic bacteria isolated from rice roots.

Ultrasonic contrast studies for the detection of cardiac shunts.

Contrast echocardiography has achieved importance in the diagnosis of cardiac shunt lesions. The technique provides information about flow patterns and serves as an adjunct to identifying communications that may be too small to image, even with high resolution real time scanning. This report reviews clinical applications and experiences in the use of standard, peripherally injected echocardiographic contrast agents for the detection of atrial septal defect, ventricular septal defect and patent ductus arteriosus. The importance and development of transpulmonary contrast agents capable of crossing the pulmonary capillary bed to opacify the left ventricle are reviewed and experience with a variety of experimental echocardiographic contrast agents is presented. Agents opacifying the left ventricle after intravenous injection are capable of providing direct ultrasonic contrast imaging of congenital left to right shunts. Further, recent experience with an experimental standardized, gas-producing contrast agent in an open chest animal model with an experimentally produced ventricular septal defect suggests that a combination of an experimental right heart agent that produces a measurable and reproducible amount of contrast effect, with a videodensitometric system capable of quantifying both positive and negative contrast effects, may provide an ultrasonic method for evaluating the magnitude of cardiac shunts.

Noninvasive quantification of stenotic semilunar valve areas by Doppler echocardiography.

Fourteen patients, aged 1 month to 13 years, with congenital semilunar valve stenosis (11 pulmonary and 3 aortic) were studied for orifice area quantification calculated from a Doppler echocardiographic equation: Area = SV/0.88 X V2 X VET, where SV = stroke volume, V2 = maximal velocity and VET = ventricular ejection time. Results from individual measurements used in this formula and derived area were compared with individual results from cardiac catheterization and valve area derived from the Gorlin formula. Ventricular ejection time by cardiac catheterization ranged from 0.17 to 0.44 second (mean +/- standard deviation [SD] 0.27 +/- 0.09), and by Doppler study from 0.20 to 0.41 second (mean +/- SD 0.29 +/- 0.06) (r = 0.65, standard error of the estimate [SEE] = 0.03, y = 0.149 + 0.528x). Pressure gradient by catheterization ranged from 30 to 125 mm Hg (mean +/- SD 56.6 +/- 33.1), and by Doppler study from 17.6 to 100 mm Hg (mean +/- SD 46.8 +/- 27.9) (r = 0.91, SEE = 8.8, y = 1.23 + 0.904x). Stroke volume was measured by Doppler study simultaneously with cardiac catheterization in nine patients; results at cardiac catheterization with thermodilution measurements (cardiac output/heart rate) ranged from 5.5 to 53.4 cc (mean +/- SD 24.7 +/- 20), and by Doppler study from 5.8 to 46.9 cc (mean +/- SD 23 +/- 18) (r = 0.96, SEE = 3.5). Area quantification was performed in two ways. In Group 1, heart rate-matched stroke volumes from cardiac catheterization were used in the derived equation for Doppler study (all patients). In Group 2, the stroke volume used was that obtained by Doppler study, which was performed simultaneously with cardiac catheterization (nine patients).(ABSTRACT TRUNCATED AT 250 WORDS)

Prediction of gradients in fibrous subaortic stenosis by continuous wave two-dimensional Doppler echocardiography: animal studies.

The purpose of this study was to assess the accuracy of continuous wave, two-dimensional Doppler echocardiography for predicting pressure gradients across discrete subaortic stenoses. Twenty-three Newfoundland dogs with subaortic stenosis were studied by closed chest Doppler interrogation of aortic velocity from an apical view of the left ventricular outflow tract simultaneously with measurements of pressure gradient during cardiac catheterization. Continuous mode Doppler interrogation was used with two-dimensional echographic guidance (Irex model IIIB) to compare the Doppler-derived maximal velocity with the pressure gradient across the obstruction at rest and after provocation with amyl nitrite inhalation and isoproterenol infusion. The maximal velocities recorded by Doppler ranged from 98 to 539 cm/s and correlated with hemodynamic gradients ranging from 3 to 123 mm Hg (r = 0.92, SEE = 37 cm/s). Doppler velocities were converted to gradients using a simplification of the Bernoulli relation (gradient = 4 X maximal velocity2); the resulting Doppler-derived gradients also correlated closely with the catheterization-measured pressure gradients (r = 0.95, SEE = 7.1 mm Hg). The predictive capability of Doppler echocardiography for estimating the pressure gradient across fibromuscular subaortic obstructions in this group of dogs with a spectrum of disease similar to that found in human beings was validated. The results also indicate that Doppler methods may have clinical applications in patients with subaortic stenosis.

Doppler color flow mapping of simulated in vitro regurgitant jets: evaluation of the effects of orifice size and hemodynamic variables.

The spatial distribution of simulated regurgitant jets imaged by Doppler color flow mapping was evaluated under constant flow and pulsatile flow conditions. Jets were simulated through latex tubings of 3.2, 4.8, 6.35 and 7.9 mm by varying flow rates from 137 to 1,260 cc/min. Color jet area was linearly related to flow rate at each orifice (r = 0.96, SEE = 3.4; r = 0.99, SEE = 1.6; r = 0.97, SEE = 2.3; r = 0.97, SEE = 3.2, respectively), but significantly higher flow rates were required to maintain the same maximal spatial distribution of the jet at the larger regurgitant orifices. Constant flow jets were also simulated through needle orifices of 0.2, 0.5 and 1 mm, with a known total volume (5 cc) injected at varying flow rates and with differing absolute volumes injected at the same flow rate (0.2, 1.0 and 2.0 cc/s, respectively). Again, maximal color jet area was linearly related to flow rate at each orifice (r = 0.97, SEE = 2.3; r = 0.97, SEE = 2.4; r = 0.92, SEE = 3.9, respectively), but was not related to the absolute volume of regurgitation. Color encoding of regurgitant jets on Doppler color flow maps was demonstrated to be highly dependent on velocity and, hence, driving pressure, such that color encoding was obtained from a constant flow jet injected at a velocity of 4 m/s through an orifice of 0.04 mm diameter with flow rates as low as 0.008 cc/s. Mitral regurgitant jets were also simulated in a physiologic in vitro pulsatile flow model through three prosthetic valves with known regurgitant orifice sizes (0.2, 0.6 and 2.0 mm2). For each regurgitant orifice size, color jet area at each was linearly related to a regurgitant pressure drop (r = 0.98, SEE = 0.15; r = 0.97, SEE = 0.20; r = 0.97, SEE = 0.23, respectively), regurgitant stroke volume (r = 0.77, SEE = 0.55; r = 0.94, SEE = 0.30; r = 0.91, SEE = 0.41, respectively) and peak regurgitant flow rate (r = 0.98, SEE = 0.16; r = 0.97, SEE = 0.21; r = 0.93, SEE = 0.37, respectively), but the spatial distribution of the regurgitant jets was most highly dependent on the regurgitant pressure drop. Jet kinetic energy calculated from the summation of the individual pixel intensities integrated over the jet area was closely related to driving pressure (r = 0.84), but integration of the power mode area times pixel intensities provided the best estimation of regurgitant stroke volume (r = 0.80).(ABSTRACT TRUNCATED AT 400 WORDS)

A new method for noninvasive estimation of ventricular septal defect shunt flow by Doppler color flow mapping: imaging of the laminar flow convergence region on the left septal surface.

An accurate but simple and noninvasive method for quantifying flow across a ventricular septal defect has yet to be implemented for routine clinical use. A region of flow convergence is commonly imaged by Doppler color flow mapping on the left septal surface of the ventricular septal defect, appearing as a narrowed region of laminar flow with aliased flow velocities entering the orifice. If the first aliasing region represents a hemispheric isovelocity boundary of a surface of flow convergence and all flow at this surface crosses the ventricular septal defect, the flow through the defect can be estimated by using the radius (R), measured from the first alias to the orifice, and the Nyquist limit (NL) velocity (the flow velocity at the first alias). Doppler color flow imaging was performed in 18 children with a single membranous ventricular septal defect undergoing cardiac catheterization at a mean age of 29.8 months (Group I). Indexes of maximal flow rate across the defect were developed from either the radius or the area, obtained by planimetry, of the first alias, based on Doppler color flow images. All indexes were corrected for body surface area and compared with shunt flow (Qp-Qs) and pulmonary to systemic flow ratio (Qp/Qs) determined at cardiac catheterization. Doppler color flow indexes derived from images of flow convergence in both the long-axis (n = 15) and oblique four-chamber (n = 10) views correlated closely with Qp/Qs (r = 0.71 to 0.92) and Qp - Qs (r = 0.69 to 0.97).(ABSTRACT TRUNCATED AT 250 WORDS)

Real-time Doppler color flow mapping for detection of patent ductus arteriosus.

In this study, ultrasound Doppler color flow mapping systems were utilized to examine flow in the pulmonary artery in 31 premature and term infants (aged 4 hours to 9 months) with patent ductus arteriosus accompanying respiratory distress syndrome, as an isolated lesion, or with patent ductus in association with other cyanotic or acyanotic congenital heart disorders. The flow mapping patterns were compared with those of a control population of 15 infants who did not have patent ductus arteriosus. In unconstricted ductus arteriosus, the flow from the aorta into the pulmonary artery was detected in late systole and early diastole and was distributed along the superior leftward lateral wall of the main pulmonary artery from the origin of the left pulmonary artery back in a proximal direction toward the pulmonary valve. In constricted patent ductus arteriosus, or especially in a ductus in association with cyanotic heart disease, the position of the ductal shunt in the pulmonary artery was more variable, often directed centrally or medially. Waveform spectral Doppler sampling could be performed in specific positions guided by the Doppler flow map to verify the phasic characteristics of the ductal shunt on spectral and audio outputs. Shunts through a very small patent ductus arteriosus were routinely detected in this group of infants, and right to left ductal shunts could also be verified by the Doppler flow mapping technique. This study suggests substantial promise for real-time two-dimensional Doppler echocardiographic flow mapping for evaluation of patent ductus arteriosus in infants.

Detection of deterioration or infection of homograft and porcine xenograft bioprosthetic valves in mitral and aortic positions by two-dimensional echocardiographic examination.

Results of two-dimensional echocardiographic examinations were compared with angiographic, hemodynamic and surgical results in 44 patients with bioprosthetic valves in mitral and aortic positions who were undergoing elective or urgent reinvestigation 24 to 87 months (mean 34) after implantation. In these patients, there were 18 homograft aortic valves in the aortic position, 9 stent-mounted homograft aortic valves in the mitral position, 13 porcine xenograft valves in the mitral position and 12 in the aortic position. Poor cusp support, gross fluttering and prolapse of cusps behind or below the anulus identified aortic insufficiency by two-dimensional echocardiography in six patients with an aortic homograft and four patients were identified with insufficiency of a stent-mounted aortic homograft in the mitral position. Two-dimensional echocardiographic examination revealed mitral stenosis in three patients with a porcine xenograft valve in the mitral position and suggested mitral insufficiency in two others. Bacterial endocarditis on homograft or porcine xenograft valves was associated with easily imaged vegetations by two-dimensional echocardiography in 10 patients. Despite difficulties in imaging valve cusps, and the skill required to obtain good echocardiographic images of bioprosthetic valves, significant valve deterioration or infected prostheses were quite effectively imaged by two-dimensional echocardiography in this study.