Effects of cardiac growth on electrical dyssynchrony in the single ventricle patient.

Single ventricle patients, including those with hypoplastic left heart syndrome (HLHS), typically undergo three palliative heart surgeries culminating in the Fontan procedure. HLHS is associated with high rates of morbidity and mortality, and many patients develop arrhythmias, electrical dyssynchrony, and eventually ventricular failure. However, the correlation between ventricular enlargement and electrical dysfunction in HLHS physiology remains poorly understood. Here we characterize the relationship between growth and electrophysiology in HLHS using computational modeling. We integrate a personalized finite element model, a volumetric growth model, and a personalized electrophysiology model to perform controlled in silico experiments. We show that right ventricle enlargement negatively affects QRS duration and interventricular dyssynchrony. Conversely, left ventricle enlargement can partially compensate for this dyssynchrony. These findings have potential implications on our understanding of the origins of electrical dyssynchrony and, ultimately, the treatment of HLHS patients.

Megacolon tóxico en una paciente con colitis seudomembranosa / Toxic megacolon in a patient with colitis pseudomembranous

La colitis seudomembranosa es una patología relacionada con el uso de antibióticos. En raras ocasiones, evoluciona a megacolon tóxico que podría requerir resolución quirúrgica. Comunicamos el caso de una mujer de 22 años, que recibió amoxicilina/ácido clavulánico unos días antes de la consulta. Presentó diarrea, fiebre y vómitos. Radiografía y tomografía computarizada de abdomen: distensión de colon derecho >6 cm. Toxina para Clostridium: positiva. Comienza con el tratamiento médico y requiere cirugía por megacolon tóxico. El megacolon tóxico es una complicación infrecuente de la colitis seudomembranosa. Es rara en pacientes jóvenes y sin comorbilidades. Se llega al diagnóstico mediante los criterios de Jalan. La tasa de mortalidad se aproxima al 70%. Se debe mantener alto nivel de alerta ante signos de toxicidad sistémica y la dilatación colónica es diagnóstica de la entidad. El uso indiscriminado de antibióticos constituye un serio factor de riesgo.(AU)

Pseudomembranous colitis is a condition associated with the use of antibiotics. On rare occasions, it evolves to toxic megacolon which may require surgical resolution. We report the case of a 22-year-old woman who received amoxicillin/clavulanic acid a few days before the consultation. She referred diarrhea, fever and vomiting. Radiography and computed tomography of abdomen: distension of the right colon >6 cm. Clostridium toxin: positive. Medical treatment is administered and surgery is needed for toxic megacolon. Toxic megacolon is an infrequent complication of pseudomembranous colitis. It is rare in young patients without comorbidities. The diagnosis is reached using the Jalan criteria. The mortality rate approaches 70%. A high level of alertness should be maintained for signs of systemic toxicity and colonic dilation is diagnostic of the entity. Indiscriminate use of antibiotics is a serious risk factor.(AU)

Prognostic value of brachioradialis muscle oxygen saturation index and vascular occlusion test in septic shock patients / Valor pronóstico del índice de saturación de oxígeno y el test de oclusión vascular en el músculo braquiorradial de pacientes con shock séptico

OBJECTIVES: To compare rSO2 (muscle oxygen saturation index) static and dynamic variables obtained by NIRS (Near Infrared Spectroscopy) in brachioradialis muscle of septic shock patients and its prognostic implications. DESIGN: Prospective and observational study. SETTING: Intensive care unit. SUBJECTS: Septic shock patients and healthy volunteers. Interventions: The probe of a NIRS device (INVOS 5100) was placed on the brachioradialis muscle during a vascular occlusion test (VOT). VARIABLES: Baseline, minimum and maximum rSO2 values, deoxygenation rate (DeOx), reoxygenation slope (ReOx) and delta value. RESULTS: Septic shock patients (n = 35) had lower baseline rSO2 (63.8 ± 12.2 vs. 69.3 ± 3.3%, p < 0.05), slower DeOx (-(-0.54 ± 0.31 vs. -0.91 ± 0.35%/s, p = 0.001), slower ReOx (2.67 ± 2.17 vs. 9.46 ± 3.5%/s, p<0.001) and lower delta (3.25 ± 5.71 vs. 15.1 ± 3.9%, p < 0.001) when compared to healthy subjects (n=20). Among septic shock patients, non-survivors showed lower baseline rSO2 (57.0 ± 9.6 vs. 69.8 ± 11.3%, p = 0.001), lower minimum rSO2 (36.0 ± 12.8 vs. 51.3±14.8%, p < 0.01) and lower maximum rSO2 values (60.6 ± 10.6 vs. 73.3 ± 11.2%, p < 0.01). Baseline rSO2 was a good mortality predictor (AUC 0.79; 95% CI: 0.63-0.94, p < 0.01). Dynamic parameters obtained with VOT did not improve the results. CONCLUSION: Septic shock patients present an important alteration of microcirculation that can be evaluated by NIRS with prognostic implications. Monitoring microvascular reactivity in the brachioradialis muscle using VOT with our device does not seem to improve the prognostic value of baseline rSO2

OBJETIVO: Comparar las variables microcirculatorias estáticas y dinámicas obtenidas mediante espectroscopia cercana al infrarojo en el músculo braquiorradial de pacientes con shock séptico y sus implicaciones pronósticas. DISEÑO: Estudio prospectivo y observacional. ÁMBITO: Unidad de Cuidados Intensivos. PACIENTES: Pacientes con shock séptico y voluntarios sanos. Intervenciones: En el músculo braquioradial de todos los sujetos se realizaron mediciones NIRS (del inglés Near Infrared Spectroscopy) durante un test de oclusión vascular. Variables: Valores rSO2 basal, mínimo y máximo, pendiente de desoxigenación, pendiente de reoxigenación y valor delta. Resultados: Los pacientes con shock séptico (n = 35) presentaron unos valores basales de rSO2 más bajos (63,8 ± 12,2 frente a 69,3 ± 3,3%; p< 0,05), una pendiente de desoxigenación y reoxigenación más lenta (-0,54 ± 0,31 frente a -0,91 ± 0,35 %/s, p = 0,001; 2,67 ± 2,17 frente a 9,46 ± 3,5%/s, p < 0,001) y un delta menor (3,25±5,71 frente a 15,1 ± 3,9%; p < 0,001) en comparación con los sujetos sanos (n = 20). De los pacientes con shock séptico, los no supervivientes presentaron unos valores basales de rSO2 más bajos (57,0 ± 9,6 frente a 69,8 ± 11,3%; p = 0,001), de rSO2 mínimo y máximo igualmente inferiores (36,0 ± 12,8 frente a 51,3 ± 14,8%; p < 0,01; 60,6 ± 10,6 frente a 73,3 ± 11,2%; p < 0,01). El rSO2 basal fue un buen factor predictivo de mortalidad (AUC 0,79; IC del 95%: 0,63-0,94; p < 0,01). Los parámetros dinámicos obtenidos mediante la prueba de oclusión vascular no mejoraron los resultados. Conclusión: Los pacientes con shock séptico presentan una alteración importante de la microcirculación que se puede evaluar mediante la espectroscopia cercana al infrarrojo con implicaciones pronósticas. La monitorización de la reactividad microvascular en el músculo braquiorradial mediante el test de oclusión vascular con nuestro dispositivo no parece mejorar el valor pronóstico de la rSO2 basal

Prognostic value of brachioradialis muscle oxygen saturation index and vascular occlusion test in septic shock patients.

OBJECTIVES: To compare rSO2 (muscle oxygen saturation index) static and dynamic variables obtained by NIRS (Near Infrared Spectroscopy) in brachioradialis muscle of septic shock patients and its prognostic implications. DESIGN: Prospective and observational study. SETTING: Intensive care unit. SUBJECTS: Septic shock patients and healthy volunteers. INTERVENTIONS: The probe of a NIRS device (INVOS 5100) was placed on the brachioradialis muscle during a vascular occlusion test (VOT). VARIABLES: Baseline, minimum and maximum rSO2 values, deoxygenation rate (DeOx), reoxygenation slope (ReOx) and delta value. RESULTS: Septic shock patients (n=35) had lower baseline rSO2 (63.8±12.2 vs. 69.3±3.3%, p<0.05), slower DeOx (-0.54±0.31 vs. -0.91±0.35%/s, p=0.001), slower ReOx (2.67±2.17 vs. 9.46±3.5%/s, p<0.001) and lower delta (3.25±5.71 vs. 15.1±3.9%, p<0.001) when compared to healthy subjects (n=20). Among septic shock patients, non-survivors showed lower baseline rSO2 (57.0±9.6 vs. 69.8±11.3%, p=0.001), lower minimum rSO2 (36.0±12.8 vs. 51.3±14.8%, p<0.01) and lower maximum rSO2 values (60.6±10.6 vs. 73.3±11.2%, p<0.01). Baseline rSO2 was a good mortality predictor (AUC 0.79; 95%CI: 0.63-0.94, p<0.01). Dynamic parameters obtained with VOT did not improve the results. CONCLUSION: Septic shock patients present an important alteration of microcirculation that can be evaluated by NIRS with prognostic implications. Monitoring microvascular reactivity in the brachioradialis muscle using VOT with our device does not seem to improve the prognostic value of baseline rSO2.

Role of peripheral hyperpolarization-activated cyclic nucleotide-modulated channel pacemaker channels in acute and chronic pain models in the rat.

Hyperpolarization-activated, cyclic nucleotide-modulated (HCN) channels contribute to rhythmic spontaneous activity in the heart and CNS. Ectopic spontaneous neuronal activity has been implicated in the development and maintenance of acute and chronic hyperalgesia, allodynia and spontaneous pain. Previously, we documented that systemic administration of ZD7288, a specific blocker of pacemaker current (I(h)), decreased ectopic activity in dorsal root ganglion (DRG) and reversed tactile allodynia in spinal nerve ligated (SNL) rats [Chaplan SR, Guo HQ, Lee DH, Luo L, Liu C, Kuei C, Velumian AA, Butler MP, Brown SM, Dubin AE (2003) Neuronal hyperpolarization-activated pacemaker channels drive neuropathic pain. J Neurosci 23:1169-1178]. Spontaneous pain is the chief clinical manifestation of peripheral nerve injury; however, a role for I(h) in spontaneous pain has not been described. Here, in further rat studies, we report that systemic administration of ZD7288 reversed spontaneous pain induced by mild thermal injury (MTI) and tactile allodynia induced by SNL and MTI. In contrast, ZD7288 did not reduce thermal hyperalgesia. An important locus of action appears to be in the skin since intraplantar (local) administration of ZD7288 completely suppressed tactile allodynia arising from MTI and SNL and reduced spontaneous pain due to MTI. Immunohistochemical staining of plantar skin sections detected HCN1-HCN4 expression in mechanosensory structures (e.g., Meissner's corpuscles and Merkel cells). Collectively, these data suggest that expression and modulation of I(h) in the peripheral nervous system, including specialized sensory structures, may play a significant role in sensory processing and contribute to spontaneous pain and tactile allodynia.

[Identification and localization of virus RNA in pepper (Capsicum anuum L.) chloroplasts by means of the PCR method]. / Identifikatsiia i opredelenie lokalizatsii virusnoi RNK v khloroplastakh pertsa (Capsicum annuum L.) metodom polimeraznoi tsennoi reaktsii.

Localization of virus RNA in stroma of Capsicum anuum L. chloroplasts was determined by the PCR method. Accumulation of virus protein in the membranes and stroma of infected pepper chloroplasts has been studied. It is concluded that the virus protein synthesis takes place in the pepper chloroplasts.

[Detection and identification of the transgenes in genetically modified plants on the example of Bt-potato]. / Detektsiia ta identyfikatsiia transheniv u henetychno modyfikovanykh roslynakh na prykladi Bt-kartopli.

We have developed diagnostic system for revealing 35S promoter CaMV and transgene CryIIIA in transgenic potato NL Russet Burbank and NL Superior companies Monsanto. Using the data about nucleotide sequences of 35S promoter (AF234316 GenBank) and gene CryIIIA (X70979 GenBank) oligonucleotides primers were synthesized for polymerase chain reaction (PCR). The technique of genomic DNA isolation from plant material, suitable for PCR has been optimized. Using Touchdown PCR method presence of specific transgene in a Bt-potato was shown. This method can be used in routine laboratory practice for revealing 35S promoter in genetically modified plants and for identification of specific transgene CryIIIA in the transformed Bt-plants.

Inactivation of olfactory sensilla of a single morphological type differentially affects the response of Drosophila to odors.

The olfactory organs on the head of Drosophila, antennae and maxillary palps, contain several hundred olfactory hairs, each with one or more olfactory receptor neurons. Olfactory hairs belong to one of three main morphological types, trichoid, basiconic, and coeloconic sensilla, and show characteristic spatial distribution patterns on the surface of the antenna and maxillary palps. Here we show that targeting expression of the cell-death gene reaper to basiconic sensilla (BS) causes the specific inactivation of most olfactory sensilla of this type with no detectable effect on other types of olfactory sensilla or the structure of the antennal lobe. Our data suggest that BS are required for a normal sensitivity to many odorants with a variety of chemical structures, through a wide range of concentrations. Interestingly, however, in contrast to other odorants tested, the behavioral response of ablated flies to intermediate concentrations of propionic and butyric acids is normal, suggesting the involvement of sensilla unaffected by ectopic reaper expression, probably coeloconic sensilla that respond strongly to these two organic acids. As inactivation of BS causes an underestimation of the concentration of both acids detectable at both the highest and lowest odorants concentrations, our results suggest that concentration coding for these two odorants relies on the integration of signals from different subsets of sensilla, most likely of different morphological types.

Spectrum and progression of conduction abnormalities in infants born to mothers with anti-SSA/Ro-SSB/La antibodies.

The classic cardiac manifestation of neonatal lupus is congenital heart block, attributed to antibody-mediated inflammation and subsequent fibrosis of the atrioventricular (AV) node. In considering the pathologic process of injury it may be that tissue damage results in a range of conduction abnormalities. Identification of less-advanced degrees of block or of fibrosis around the AV node without any conduction abnormality on EKG would support this pathologic model, and serve as a potential marker for treatment if the conduction defect could be shown to progress. To ascertain the spectrum of arrhythmias associated with maternal anti-SSA/Ro-SSB/La antibodies, records of all children enrolled in the Research Registry for Neonatal Lupus were reviewed. Of 187 children with congenital heart block whose mothers have anti-SSA/Ro-SSB/La antibodies, nine had a prolonged PR interval on EKG at birth, four of whom progressed to more advanced AV block. A child whose younger sibling had third degree block was diagnosed with first degree block at age 10 years at the time of surgery for a broken wrist. Two children diagnosed in utero with second degree block were treated with dexamethasone and reverted to normal sinus rhythm by birth, but ultimately progressed to third degree block. Four children had second degree block at birth: of these, two progressed to third degree block. Sinus bradycardia (< 100 bpm) was present in three (3.8%) of 78 fetuses for whom atrial rates were recorded by echocardiogram. Of 40 neonates for whom EKGs were available, the mean atrial rate was 137+/-20 bpm (range 75-200). These data have important research and clinical implications. In contrast to the AV node, permanent sinoatrial nodal involvement is not clinically apparent. Perhaps many fetuses sustain mild inflammation, but resolution is variable, as suggested by the presence of incomplete AV block. Since subsequent progression of less-advanced degrees of block can occur, an EKG should be performed on all infants born to mothers with anti-SSA/Ro-SSB/La antibodies.

Reentrant tachycardia using two discrete atrioventricular nodes and a concealed atriofascicular pathway.

We describe a case of reentrant supraventricular tachycardia using two discrete atrioventricular (AV) nodes in the antegrade direction and a concealed atriofascicular pathway in the retrograde direction in a 21-year-old woman with superior-inferior ventricles and ventricular inversion. Using the Carto endocardial mapping system, two discrete AV nodes were identified as well as a separate decremental AV pathway located midway between the two nodes. Ablation of the separate pathway resulted in elimination of inducible tachycardia without loss of either AV node.

Pharmacological comparison of human homomeric 5-HT3A receptors versus heteromeric 5-HT3A/3B receptors.

The present study determined the detailed pharmacological profile of heterologously expressed human (h) homomeric 5-HT3A receptors in direct comparison to heteromeric h5-HT3A/3B receptors. The very minor differences in their respective pharmacological profiles indicates that the 5-HT3B receptor subunit alters, predominantly, the biophysical rather than the pharmacological properties of the 5-HT3 receptor.

Cisapride associated with QTc prolongation in very low birth weight preterm infants.

OBJECTIVE: No systematic study has been performed to evaluate the effect of cisapride on the QT interval in premature infants. Cisapride, which has recently been withdrawn by the Food and Drug Administration and is no longer an approved therapy, was commonly used for preterm infant care to improve the advance of enteral feedings and to reduce reflux and associated apnea. Our aim was to evaluate the effect of recommended doses of cisapride on the QT interval in this population. STUDY DESIGN: Prospective blinded evaluation of electrocardiogram for QT, JT, QTc, and JTc measurements in 25 preterm infants before and after cisapride administration. RESULTS: Twelve of 25 infants (48%) developed repolarization abnormalities with cisapride administration: 32% of the infants (8/25) studied had QTc prolongation (>/=0.450 seconds), whereas 10/25 had JTc prolongation (>/=0.360 seconds). Preterm infants <32 weeks significantly prolonged their QTc interval from 0.41 +/- 0.02 to 0.44 +/- 0.02. The QTc and/or JTc was prolonged in 54% of infants receiving 0.1 mg/kg/dose and 42% receiving 0.2 mg/kg/dose. CONCLUSIONS: The QTc and JTc interval significantly prolonged in preterm infants <32 weeks on the recommended dose of cisapride therapy. A QTc >/=0.450 seconds developed in 32% of infants treated with cisapride, whereas the JTc prolonged in 40%. A significant percentage of infants (54%) developed prolonged QTc intervals at a dose of 0.1 mg/kg/dose. From these data we conclude that there is a higher risk of prolongation of the QTc interval and risk of arrhythmias with greater prematurity.

Effect of antimicrobial apomyoglobin 56-131 peptide on liposomes and planar lipid bilayer membrane.

The horse apomyoglobin 56-131 peptide is a convenient object for studies on the recently discovered antimicrobial activities of haem-binding protein fragments called haemocidins. The purpose of this study was to determine the effect of this peptide on planar lipid bilayer membranes and on liposomes of different lipid compositions. Micromolar concentrations of the apomyoglobin 56-131 fragment disrupt phosphatidylserine/phosphatidylethanolamine planar lipid bilayers without discrete conductance changes. The observed detergent-like action is dependent on peptide concentration; the lower amount of peptide resulted in longer bilayer lifetime. The cholesterol has an inhibitory effect on peptide-induced liposome lysis as shown by calcein release from liposomes. Additionally, there was considerable lytic activity on liposomes formed from anionic lipids of the sort found in bacterial membranes. Circular dichroism (CD) experiments showed that the peptide had a disordered structure in aqueous solutions and folds gradually to form helices in both membrane-mimetic trifluoroethanol solutions as well as in liposome suspensions. The features of the apomyoglobin 56-131 fragment that are similar to the cationic antimicrobial peptides acting in a 'carpet-like' manner are discussed.

Molecular cloning and biochemical characterisation of proteases from Staphylococcus epidermidis.

We report the complete coding sequence and the partial amino acid sequence (determined by chemical sequencing) of Staphylococcus epidermidis extracellular cysteine (Ecp) and serine (Esp) proteases. The first enzyme shows an extended sequence similarity to Staphylococcus aureus cysteine protease (staphopain) and the second one resembles the serine protease produced by that species. The region directly upstream of the sequence coding for the mature protein in both enzymes displays significant homology to the profragments encoded by sspB and sspA, respectively, thus suggesting that the characterised enzymes may also be produced as proproteins. Furthermore, we report some biological properties of the cysteine protease, contributing to a better understanding of its role as a possible virulence factor. The proteolytic activity of this enzyme was rapidly and efficiently inhibited by human alpha-2-macroglobulin; however, human kininogen as well as cystatins (A, C and D) were not inhibitory. Moreover, the protease was capable of inactivating, by limited proteolysis, both alpha-1-antitrypsin and HMW-kininogen, but neither alpha-1-antichymotrypsin nor antithrombin III.

Effects of hemorrhage on gastrointestinal oxygenation.

OBJECTIVES: (1) To demonstrate that metabolic parameters are better indicators of tissue hypoxia than regional and whole oxygen consumption (VO(2)). (2) To compare intramucosal pH (pHi) in different gastrointestinal segments. DESIGN: Prospective, interventional study. SETTING: Research laboratory at a university center. SUBJECTS: Fourteen anesthetized, mechanically ventilated dogs. INTERVENTIONS: Twenty milliliters per kilogram bleeding. MEASUREMENTS AND MAIN RESULTS: We placed pulmonary, aortic and mesenteric venous catheters, and an electromagnetic flow probe in the superior mesenteric artery, and gastric, jejunal and ileal tonometers to measure flows, arterial and venous blood gases and lactate, and intramucosal PCO(2). We calculated systemic and intestinal oxygen transport (DO(2)) and consumption (VO(2)), pHi and arterial minus intramucosal PCO(2) (DeltaPCO(2)). Then, we bled the dogs and repeated the measurements after 30 min. Systemic and intestinal DO(2) fell (26.0+/-7.3 versus 8.9+/-2.6 and 71.9+/-17.3 versus 24.6+/-9.6 ml/min per kg, respectively, p<0.0001). Systemic and intestinal VO(2) remained unchanged (5.5+/-1.3 versus 5.4+/-1.3 and 15.7+/-5.0 versus 14.9+/-5.3 ml/min per kg, respectively). Gastric, jejunal and ileal pHi (7.13+/-0.11 versus 6.96+/-0.17, 7.18+/-0.06 versus 6.97+/-0.15, 7.12+/-0.11 versus 6.94+/-0.14, p<0.05) and DeltaPCO(2) (21+/-13 versus 35+/-23, 15+/-5 versus 33+/-16, 23+/-17 versus 38+/-20, p<0.05) changed accordingly. Arterial and mesenteric venous lactate and their difference, rose significantly (1.7+/-0.9 versus 3.7+/-1.4 and 1.8+/-0.8 versus 4.3+/-1.5 mmol/l, 0.1+/-0.6 versus 0.6+/-0.7 mmol/l, p<0.05). CONCLUSIONS: During hemorrhage, systemic and intestinal VO(2) remained stable. However, hyperlactatemia and intramucosal acidosis evidenced anaerobic metabolism. pHi changes paralleled in the three intestinal segments.

Using 12-lead ECG and synthesized VCG in detection of right ventricular hypertrophy with terminal right conduction delay versus partial right bundle branch block in the pediatric population.

In pediatric electrocardiogram (ECG) analysis, mild right ventricular hypertrophy (RVH) and especially mild RVH with terminal right conduction delay (RVHtcd) are often confused with partial right bundle branch block (PRBBB). This is problematic for computer ECG analysis algorithms and even for most experienced pediatric cardiologists. This study was designed to achieve better classification of mild RVHtcd and PRBBB by combining the 12-lead synthesized vectocardiogram (VCG) transverse plane measurements with scalar ECG measurements. Pediatric ECGs used in the study were recorded with 15 leads and a 500 Hz sampling rate at the Lucile Salter Packard Children's Hospital, Stanford University Medical Center. Out of 4,200 ECGs collected consecutively over a period of 18 months, 447 RVH, 335 RBBB and 589 Normal were interpreted by expert pediatric cardiologists, and were included in the study. Statistical comparison of ECG and VCG measurements were done in stratified ECG sets (412) that have a visually indistinguishable waveform pattern, 117 RVHtcd, 96 PRBBB and 199 normal, showed significant differences in initial and terminal vectors in the transverse plane. The mean angle of the initial vector was anterior (57.2 degrees +/- 41.8) in the normal group, left anterior in the PRBBB group (34.4 degrees +/- 39.5) and in the RVHtcd group (31.9 degrees +/- 41.0) and. The mean angle of the terminal vector was right anterior (158.3 degrees +/- 36.8) in the PRBBB group, rightward (179.7 degrees +/- 29.9) in the RVHtcd group and right posterior (212.6 degrees +/- 37.8) in the normal group. These are clearly applicable features for a classification algorithm. Significantly improved classification results were obtained from a new algorithm using combined ECG and VCG measurements versus an existing algorithm. The limitation of this study stems from the unavailability of a more reliable gold standard. It may be necessary to used body surface potentials obtained with a large number of electrodes to accurately differentiate the study groups.