Effects of cardiopulmonary bypass surgery on coronary flow in children assessed with transthoracic Doppler echocardiography

Perturbation of coronary blood flow (CF) is an important contributor to myocardium-related complications. The study was primarily designed to assess the impact of cardiopulmonary bypass (CPB) surgery on CF by aid of transthoracic Doppler echocardiography. Changes in CF after off-pump coarctation surgery were also studied. All ultrasounds were performed before and 5 +/- 1 days after surgery. Eighteen children underwent CPB surgery of ventricular left-to-right shunts at the mean age of 6 mo, while off-pump surgery (aortic coarctectomy) was undertaken at the mean age of 10 days in 12 children. After CPB surgery, both left anterior descending coronary artery mean diameter and basal CF increased from 1.7 +/- 0.3 to 2.1 +/- 0.4 mm (P = 0.001) and 27 +/- 10 to 47 +/- 15 ml/min (P = 0.0001), respectively. These two coronary variables decreased after off-pump coarctectomy: left anterior descending coronary artery mean diameter from 1.8 +/- 0.1 to 1.7 +/- 0.1 mm (P = 0.06), and CF from 44 +/- 12 to 25 +/- 8 ml/min (P = 0.001). The findings are in keeping with the hypothesis that the previously reported impairment of coronary flow reserve after CPB surgery could be due to increase in basal coronary flow after CPB. Off-pump coarctectomy seems to have little impact on CF, as the postsurgical decline in flow in these patients seems to relate to the reduction in cardiac pressure afterload.     

LPS-induced microvascular leukocytosis can be assessed by blue-field entoptic phenomenon

Administration of low doses of Escherichia coli endotoxin [a lipopolysaccharide (LPS)] to humans enables the study of inflammatory mechanisms. The purpose of the present study was to investigate whether the blue-field entoptic technique may be used to quantify the increase in circulating leukocytes in the ocular microvasculature after LPS infusion. In addition, combined laser Doppler velocimetry and retinal vessel size measurement were used to study red blood cell movement. Twelve healthy male volunteers received 20 IU/kg iv LPS as a bolus infusion. Outcome parameters were measured at baseline and 4 h after LPS administration. In the first protocol (n = 6 subjects), ocular hemodynamic effects were assessed with the blue-field entoptic technique, the retinal vessel analyzer, and laser Doppler velocimetry. In the second protocol (n = 6 subjects), white blood cell (WBC) counts from peripheral blood samples and blue-field entoptic technique measurements were performed. LPS caused peripheral blood leukocytosis and increased WBC density in ocular microvessels (by 49%; P = 0.036) but did not change WBC velocity. In addition, retinal venous diameter was increased (by 9%; P = 0.008), but red blood cell velocity remained unchanged. The LPS-induced changes in retinal WBC density and leukocyte counts were significantly correlated (r = 0.87). The present study indicates that the blue-field entoptic technique can be used to assess microvascular leukocyte recruitment in vivo. In addition, our data indicate retinal venous dilation in response to endotoxin.     

The extant Chaoborus assemblage can be assessed using subfossil mandibles

1. Assemblages of Chaoborus were examined in 80 thermally stratified southern central Canadian Shield lakes to explore whether subfossil mandibles could be useful in assemblage‐level studies of Chaoborus. 2. Chaoborus (Sayomyia) (probably Chaoborus punctipennis in this study region) and Chaoborus flavicans were the most common taxa recorded, while Chaoborus trivittatus was rarer. Chaoborus americanus was not recorded in subfossil assemblages, because no fishless lakes were included in this study. Chaoborus flavicans had higher relative abundances (%) in lakes with higher dissolved organic carbon (DOC), probably because of reduced fish predation in less transparent water. 3. Results from logistic regression indicate that patterns of presence/absence for Chaoborus mandibles in the study lakes were influenced primarily by hypolimnetic oxygen concentration, probably because of the presence or extent of a hypolimnetic refugium from fish predation. 4. Chaoborus species richness in lakes, derived from subfossil assemblages, did not differ significantly from species richness estimates derived from plankton sampling with a net. Patterns of dominance and coexistence [e.g. the widespread co‐occurrence of C. flavicans and C. (Sayomyia)] determined from subfossil assemblages agreed with previous studies of the contemporary living assemblage. 5. These results suggest that subfossil assemblages may be used as an alternative to nocturnal plankton sampling to carry out research on the community ecology of Chaoborus. 6. We propose a hierarchical conceptual model of assemblage‐level patterns of Chaoborus in temperate lakes. Chaoborus americanus dominates in fishless lakes, whereas in lakes with fish Chaoborus is typically absent where there is no anoxic hyplimnion. In lakes with anoxic strata, C. trivittatus tends to dominate in lakes with few fish; in the remaining lakes, C. flavicans and C. (Sayomyia) dominate, although C. flavicans is more relatively abundant in lakes with lower water clarity (higher DOC).     

Detection of cerebral embolism using transcranial Doppler sonography: can artifacts be reliably recognized?]

A requirement for the use of TCD for the detection of emboli in the field of cardiac and vascular surgery is the reliable differentiation between true emboli and artifacts. In ten healthy volunteers we carried out a study to establish the method with which artefacts can most reliably be identified. Automatic detection of increasing signal intensity misinterpreted 14% of all artifacts as emboli; 1.7% of all artifacts sounded suspicious for embolism, and 0.6% met the classical criteria of an embolus. Using simultaneous recording of the flow signal in two sections of the middle cerebral artery, all artifacts were identified on the basis of their simultaneous manifestation. Reliable intra-operative differentiation of emboli from artifacts requires attentive, continuous acoustic and visual analysis of signals by an experienced investigator familiar with the surgical procedure. The introduction of a multiple-depth algorithm might significantly improve the automatic detection program.     

Coronary flow reserve and heart failure in experimental coxsackievirus myocarditis. A transthoracic Doppler echocardiography study

The objective of this study was to apply transthoracic Doppler echocardiography (TTDE) in mice to study coronary flow reserve (CFR), an index of coronary microvascular function, in mild and severe forms of experimental viral myocarditis. Regarding methodology, BALB/c mice were infected with cardiotropic coxsackieviruses causing either a mild (Nancy strain) or a severe (Woodruff strain) myocarditis. Left ventricular dimensions, fractional shortening, and CFR (ratio of left coronary artery flow velocity during maximal adenosine-induced vasodilatation to rest) were measured by TTDE before infection and again 1 or 2 wk after infection. As a result, the resting flow velocity did not change after infection. In contrast, CFR reduced significantly 1 wk after infection with either virus variant [from 2.5 (SD 0.3) to 1.4 (SD 0.1) in severe and from 2.4 (SD 0.4) to 2.1 (SD 0.3) in mild myocarditis], being significantly lower in the severe than mild myocarditis. CFR remained low in severe myocarditis 2 wk after infection. Fractional shortening decreased to the same levels 1 wk after infection with either virus variant [from 0.54 (SD 0.02) to 0.43 (SD 0.03) in severe and from 0.51 (SD 0.03) to 0.44 (SD 0.02) in mild myocarditis, P < 0.05]. However, 2 wk after infection, mice with severe myocarditis had enlarged left ventricles and lower fractional shortening [0.31 (SD 0.03)] than mice with mild myocarditis [0.47 (SD 0.02), P < 0.01]. In conclusion, CFR measured with TTDE is reduced in coxsackievirus myocarditis in mice. Low CFR is associated with progressive heart failure, indicating that dysfunction of coronary microcirculation is a determinant of poor outcome in viral myocarditis.     

Time of death of CNS tumor-bearing rats can be reliably predicted by body weight-loss patterns.

A request by the Institutional Animal Care and Use Committee for an alternative to death as an end point in a cancer research project using a rat brain 9L tumor cell model led to a search for reliable criteria for predicting time of death in this type of experiment. These experiments evaluated the therapeutic effectiveness of radiation alone, continuous intracerebral infusions of 5-iodo-2-deoxyuridine (IUDR) alone, and a combination of both therapies. We found that a characteristic pattern of body weight changes occurs after injection of 9L tumor cells into the brain ventricles or parenchyma. The initial phase was characterized by a loss of body weight which appeared to be related to surgery and, in the irradiated groups, to the subsequent doses of radiation under anesthesia on days 4, 6, and 7. After this initial phase (phase 1), a second period of weight change (phase 2) which was characterized by an overall gain of body weight interrupted temporarily in 76 out of the 149 rats by reversible episodes of weight loss of 1 to 5 days duration. The length of this phase 2 weight gain period was significantly extended by XRT-IUDR treatment in the rats with intraparenchymal tumors. The third and final phase consisted of a period of irreversible weight loss which may be related to cachexia. The third phase was similar in duration for control, XRT, IUDR and XRT-IUDR groups of rats and had a mean length of 9.8 +/- 0.27 days.(ABSTRACT TRUNCATED AT 250 WORDS)     

KRAS and BRAF mutation analysis can be reliably performed on aspirated cytological specimens of metastatic colorectal carcinoma

N. K. B. Pang, M. E. Nga, S. Y. Chin, T.‐M. Ismail, G. L. Lim, R. Soong and M. Salto‐Tellez
KRAS and BRAF mutation analysis can be reliably performed on aspirated cytological specimens of metastatic colorectal carcinoma Background: Sanger sequencing is one of several reliable methods in use to detect KRAS and BRAF mutations to facilitate clinical patient selection for anti‐epidermal growth factor receptor (EGFR) monoclonal antibody therapy in unresectable metastatic colorectal adenocarcinoma (CRC). Most analyses are made on pretreatment biopsy or resection specimens. There is a scarcity of published studies on the suitability of cytological samples for KRAS testing in this setting. Methods: DNA extraction was attempted on 11 search‐retrieved paired cases of histological resections or excisions of CRC and their corresponding cytological samples (representing metastases) and tested for KRAS mutations in exon 2 and 3, as well as BRAF exon 15 mutations by Sanger sequencing. Only KRAS wild‐type cases were subjected to BRAF analysis because this is the setting with true diagnostic value, as these mutations are mutually exclusive. Results: Of the 11 paired cases analysed, only eight histology cases showed satisfactory DNA quality for sequencing. Thus, only eight of the corresponding cytology cases were analysed. Seven of the eight cases tested showed the same KRAS genotype on both the aspirated cytology specimen of metastatic carcinoma and the primary tumour (histological specimen), from which we derive an overall concordance rate of 87.5%. The single discordant case was likely to be a true difference as it was demonstrated again on repeat testing of both samples. No BRAF mutations were detected on the four KRAS wild‐type cases. Conclusion: A range of cytological samples are suitable for KRAS and BRAF mutation testing, be it from previously stained preparations or cell blocks. These samples would be highly valuable in cases where cytological samples are the only material available for mutation testing.     

The interplay between phenotypic and ontogenetic plasticities can be assessed using reaction-diffusion models

Every morphological, behavioral, or even developmental character expression of living beings is coded in its genotype and is expressed in its phenotype. Nevertheless, the interplay between phenotypic and ontogenetic plasticities, that is, the capability to manifest trait variations, is a current field of research that needs morphometric, numerical, or even mathematical modeling investigations. In the present work, we are searching for a phenotypic index able to identify the underlying correlation among phenotypic, ontogenetic, and geographic distribution of the evolutionary development of species of the same genus. By studying the case of Pseudoplatystoma fishes, we use their skin patterns as an auxiliary trait that can be reproduced by means of a reaction diffusion (RD) model. From this model, we infer the phenotypic index in terms of one of the parameters appearing in the mathematical equations. To achieve this objective, we perform extensive numerical simulations and analysis of the model equations and link the parameter variations with different environmental and physicochemical conditions in which the individuals develop, and which may be regulated by the ontogenetic plasticity of the species. Our numerical study indicates that the patterns predicted by a set of reaction diffusion equations are not uniquely determined by the value of the parameters of the equation, but also depend on how the process is initiated and on the spatial distribution of values of these parameters. These factors are therefore significant, since they show that an individual’s growth dynamics and apparent secondary transport processes, like advection, can be determinant for the alignment of motifs in a skin pattern. Our results allow us to discern the correlation between phenotypic, ontogenetic, and geographic distribution of the different species of Pseudoplatystoma fishes, thus indicating that RD models represent a useful taxonomic tool able to quantify evolutionary indexes.     

Choices between red clover and fescue in the diet can be reliably estimated in heifers post-weaning using n-alkanes

Measuring diet choice in grazing animals is challenging, complicating the assessment of feed efficiency in pasture-based systems. Furthermore, animals may modify their intake of a forage species depending on its nutritive value and on their own physiological status. Various fecal markers have been used to estimate feed intake in grazing animals. However, plant-wax markers such as n-alkanes (ALK) and long-chain alcohols may provide reliable estimates of both dietary choices and intakes. Still, their use in beef cattle has been relatively limited. The present study was designed to test the reliability of the ALK technique to estimate diet choices in beef heifers. Twenty-two Angus-cross heifers were evaluated at both post-weaning and yearling age. At each age, they were offered both red clover and fescue hay as cubes. Following 3-week acclimation periods, daily intake of each forage species was assessed daily for 10 days. During the final 5 days, fecal grab samples were collected twice daily. The ALK fecal concentrations were adjusted using recovery fractions compiled from literature. Diet composition was estimated using two statistical methods. Post-weaning, dietary choices were reliably estimated, with low residual error, regardless of the statistical approach adopted. The regression of observed on estimated red clover proportion ranged from 0.85±0.08 to 1.01±0.09 for fecal samples collected in the p.m. and for daily proportions once averaged, respectively. However, at yearling age, the estimates were less reliable. There was a tendency to overestimate the red clover proportion in diets of heifers preferring fescue, and vice versa. This was due to greater variability in ALK fecal concentrations in the yearling heifers. Overall, the ALK technique provided a reliable tool for estimating diet choice in animals fed a simple forage diet. Although further refinements in the application of this methodology are needed, plant-wax markers provide opportunities for evaluating diet composition in grazing systems in cattle.     

Type III collagen can be present on banded collagen fibrils regardless of fibril diameter

Monoclonal antibodies that recognize an epitope within the triple helix of type III collagen have been used to examine the distribution of that collagen type in human skin, cornea, amnion, aorta, and tendon. Ultrastructural examination of those tissues indicates antibody binding to collagen fibrils in skin, amnion, aorta, and tendon regardless of the diameter of the fibril. The antibody distribution is unchanged with donor age, site of biopsy, or region of tissue examined. In contrast, antibody applied to adult human cornea localizes to isolated fibrils, which appear randomly throughout the matrix. These studies indicate that type III collagen remains associated with collagen fibrils after removal of the amino and carboxyl propeptides, and suggests that fibrils of skin, tendon, and amnion (and presumably many other tissues that contain both types I and III collagens) are copolymers of at least types I and III collagens.     

The likelihood of aggregation during protein renaturation can be assessed using the second virial coefficient

Protein aggregation is commonly observed during protein refolding. To better understand this phenomenon, the intermolecular interactions experienced by a protein during unfolding and refolding are inferred from second virial coefficient (SVC) measurements. It is accepted that a negative SVC is indicative of protein-protein interactions that are attractive, whereas a positive SVC indicates net repulsive interactions. Lysozyme denatured and reduced in guanidinium hydrochloride exhibited a decreasing SVC as the denaturant was diluted, and the SVC approached zero at approximately 3 M GdnHCl. Further dilution of denaturant to renaturation conditions (1.25 M GdnHCl) led to a negative SVC, and significant protein aggregation was observed. The inclusion of 500 mM L-arginine in the renaturation buffer shifted the SVC to positive and suppressed aggregation, thereby increasing refolding yield. The formation of mixed disulfides in the denatured state prior to refolding also increased protein solubility and suppressed aggregation, even without the use of L-arginine. Again, the suppression of aggregation was shown to be caused by a shift from attractive to repulsive intermolecular interactions as reflected in a shift from a negative to a positive SVC value. To the best of our knowledge, this is the first time that SVC data have been reported for renaturation studies. We believe this technique will aid in our understanding of how certain conditions promote renaturation and increase protein solubility, thereby suppressing aggregation. SVC measurements provide a useful link, for protein folding and aggregation, between empirical observation and thermodynamics.     

Diagnosis of intra- and pericardial tumor with transthoracic and transesophageal 2D echocardiography

To examine the value of the combined approach of transthoracic and transesophageal 2D-echocardiography in diagnosis of heart tumors this study was performed on 30 patients (11 males, 19 females, age 15 to 82 years) with atrial (n = 17) and pericardial (n = 13) tumors. Echocardiography was performed using an electronic sector scanner (Varian 3400 R) and a 2.25 MHz transducer for the transthoracic approach and a 3.5 MHz transducer at the tip of a 9 mm gastroscope for examination from the esophagus. In 9 of 11 patients with atrial myxoma diagnosis was established by transthoracic echocardiography, whereas in 2 cases with reduced image quality at the conventional approach the tumor was identified by the transesophageal technique. In one of 5 patients with atrial thrombi acoustic properties and mobility could be better judged by transesophageal echocardiography. In 7 of 13 cases with pericardial tumors diagnosis was established by transthoracic echocardiography, whereas in 6 cases diagnosis was achieved by the transesophageal approach only. Thus, transesophageal echocardiography is suggested a decisive additional tool in diagnosis of heart tumors.     

Activated platelets in carotid artery thrombosis in mice can be selectively targeted with a radiolabeled single-chain antibody

Background

Activated platelets can be found on the surface of inflamed, rupture-prone and ruptured plaques as well as in intravascular thrombosis. They are key players in thrombosis and atherosclerosis. In this study we describe the construction of a radiolabeled single-chain antibody targeting the LIBS-epitope of activated platelets to selectively depict platelet activation and wall-adherent non-occlusive thrombosis in a mouse model with nuclear imaging using in vitro and ex vivo autoradiography as well as small animal SPECT-CT for in vivo analysis.

Methodology/Principal Findings

LIBS as well as an unspecific control single-chain antibody were labeled with ¹¹¹Indium (¹¹¹In) via bifunctional DTPA ( = ¹¹¹In-LIBS/¹¹¹In-control). Autoradiography after incubation with ¹¹¹In-LIBS on activated platelets in vitro (mean 3866±28 DLU/mm², 4010±630 DLU/mm² and 4520±293 DLU/mm²) produced a significantly higher ligand uptake compared to ¹¹¹In-control (2101±76 DLU/mm², 1181±96 DLU/mm² and 1866±246 DLU/mm²) indicating a specific binding to activated platelets; P<0.05. Applying these findings to an ex vivo mouse model of carotid artery thrombosis revealed a significant increase in ligand uptake after injection of ¹¹¹In-LIBS in the presence of small thrombi compared to the non-injured side, as confirmed by histology (49630±10650 DLU/mm² vs. 17390±7470 DLU/mm²; P<0.05). These findings could also be reproduced in vivo. SPECT-CT analysis of the injured carotid artery with ¹¹¹In-LIBS resulted in a significant increase of the target-to-background ratio compared to ¹¹¹In-control (1.99±0.36 vs. 1.1±0.24; P<0.01).

Conclusions/Significance

Nuclear imaging with ¹¹¹In-LIBS allows the detection of platelet activation in vitro and ex vivo with high sensitivity. Using SPECT-CT, wall-adherent activated platelets in carotid arteries could be depicted in vivo. These results encourage further studies elucidating the role of activated platelets in plaque pathology and atherosclerosis and might be of interest for further developments towards clinical application.     

Imaging of a non-coronary sinus of Valsalva aneurysm with transthoracic echocardiography and multi-slice computed tomography

A 46-year-old female with a giant aneurysm of the non-coronary sinus of Valsalva, associated with moderate aortic valve regurgitation, is described. The aneurysm was detected by echocardiography in a patient who was complaining of paroxysmal palpitations. The patient was accepted for aneurysmectomy. In this case report the possible aetiologies and clinical aspects of the aneurysm are reviewed. Treatment and the role of multi-sliced computed tomography (MSCT) in heart disease are discussed.