Physiological and metabolic responses in newborn piglets associated with the birth order.

The objective of this study was to evaluate the effect of birth order on the physiological and metabolic responses of the newborn piglet the first hours after birth. A total of 281 randomly selected newborn piglets were included, classified according to birth order in 12 groups (L1-L12). The expulsion interval, neonatal vitality, latency in connecting to the maternal teat and physiological profile were recorded for each piglet. The number of piglets born alive and dead was also recorded. The blood gases, electrolytes and glucose levels of the neonates were obtained by means of an automatic blood gas and electrolyte analyzer. Groups L1, L2, L11, and L12 had the least score on the vitality scale, the longest expulsion intervals, and longest latency to connect with the maternal teat, as well as greater physiological alterations (hyperglycemia, hyperlactatemia and hypercapnia) compared to groups L4 to L9. Likewise, type-II stillbirths only occurred in the first and last quarter of the birth order of the litter. In conclusion, piglets born in the first and last quarter of the birth order of the litter had a greater risk of having physiological and behavioral alterations during farrowing.

Seroprevalence and risk factors associated with bovine herpesvirus 1 and bovine viral diarrhea virus in North-Eastern Mexico.

Bovine herpesvirus 1 (BoHV-1) and bovine viral diarrhea virus (BVDV) are well known etiological agents of cattle that produce important economic losses due to reproductive failures and calf mortality, as well as enteric and respiratory disease. Tamaulipas is located northeast of Mexico, an important cattle production and the principal exporter of calf and heifer to the United States. The objectives of this study were to estimate the seroprevalence of BoHV-1 and of BVDV, and to determine the effects of risk factors on these infections. Blood samples of cattle from 57 farms from rural districts of Tamaulipas were collected. The samples were tested for antibodies against BoHV-1 and BVDV using commercial ELISA kits. Data on potential risk factors were obtained using a questionnaire administered to the farmer at the time the blood samples were taken. The seroprevalences for BoHV-1 and BVDV were 64.4% and 47.8%, respectively. In the logistic regression analysis, the significant risk factors were rural district, herd size and cattle introduced to the farm. This study confirms the high seroprevalence of BoHV-1 and BVDV in unvaccinated cattle in Tamaulipas, Mexico. The results of this study could be used for the development of BoHV-1 and BVDV prevention and control program in North-Eastern, Mexico.

Evaluation of the protective effect of thiamine pyrophosphate based on the biochemical analysis of rabbit foetuses at 30 days of gestation.

This study evaluated the effects of thiamine pyrophosphate (PPT) on the biochemical profiles of full-term rabbit foetuses that were subjected to experimental ischemia followed by 24h reperfusion. A total of 16 gestating rabbit dams were divided into two groups, one of which was treated by administering PPT and subjected to a process ischemia. During this interval, fetal blood samples were drawn from each dam (in the ischemia group) at 0, 15 and 45min. Ischemia for 15 and 45min was not associated with changes in lactate levels of the Ischemia group foetuses. However, in the foetuses in the reperfusion groups without PPT lactate levels were significantly higher after 15 and 45min of arterial occlusion compared to time zero. These results demonstrate that PTT alters some acute and some longer-term biochemical outcomes of uterine ischemia perhaps important in preserving energy metabolism under hypoxic conditions.

A noninvasive imaging modality for cardiac arrhythmias.

BACKGROUND: The last decade witnessed an explosion of information regarding the genetic, molecular, and mechanistic basis of heart disease. Translating this information into clinical practice requires the development of novel functional imaging modalities for diagnosis, localization, and guided intervention. A noninvasive modality for imaging cardiac arrhythmias is not yet available. Present electrocardiographic methods cannot precisely localize a ventricular tachycardia (VT) or its key reentrant circuit components. Recently, we developed a noninvasive electrocardiographic imaging modality (ECGI) that can reconstruct epicardial electrophysiological information from body surface potentials. Here, we extend its application to image reentrant arrhythmias. METHODS AND RESULTS: Epicardial potentials were recorded during VT with a 490 electrode sock during an open chest procedure in 2 dogs with 4-day-old myocardial infarctions. Body surface potentials were generated from these epicardial potentials in a human torso model. Realistic geometry errors and measurement noise were added to the torso data, which were then used to noninvasively reconstruct epicardial isochrones, electrograms, and potentials with excellent accuracy. ECGI reconstructed the reentry pathway and its key components, including (1) the central common pathway, (2) the VT exit site, (3) lines of block, and (4) regions of slow and fast conduction. This allowed for detailed characterization of the reentrant circuit morphology. CONCLUSIONS: ECGI can noninvasively image arrhythmic activation on the epicardium during VT to identify and localize key components of the arrhythmogenic pathway that can be effective targets for antiarrhythmic intervention.

Imaging dispersion of myocardial repolarization, I: comparison of body-surface and epicardial measures.

BACKGROUND: Body-surface ECG measures (QT dispersion [QTd], QRST integrals) have been used as indices of myocardial repolarization abnormalities with the goal of identifying patients at risk of fatal arrhythmias. The clinical utility of these measures has been questioned. We investigate the complex relationship between epicardial and body-surface potentials in the context of regionally abnormal myocardial repolarization. METHODS AND RESULTS: Epicardial potentials were recorded with a 224-electrode sock from an open-chest dog during control, regional epicardial warming, cooling, and adjacent warming and cooling to induce localized alterations in myocardial repolarization and regions of increased repolarization dispersion. Body-surface potentials were generated from these epicardial potentials in a human torso model. Epicardial estimates of repolarization (activation recovery intervals [ARIs] and QRST integrals) were evaluated for their ability to identify regions with increased repolarization dispersion. Body-surface QRST integrals and QTd in 12-lead ECG and 64-lead body-surface potential maps were evaluated for their ability to detect increased dispersion of myocardial repolarization. Epicardial ARI and QRST integral maps successfully located epicardial regions with increased dispersion of repolarization. The increased dispersion was not consistently reflected in the 12-lead or 64-lead ECG QTd or in the body-surface QRST integral maps. CONCLUSIONS: This study demonstrates the inadequacy of body-surface measures that are thought to reflect myocardial dispersion of repolarization. In contrast, measures based on epicardial electrograms (ARI or epicardial QRST integral maps) provide physiologically relevant information about myocardial repolarization and can locate regions of increased dispersion.

Imaging dispersion of myocardial repolarization, II: noninvasive reconstruction of epicardial measures.

BACKGROUND: Dispersion of myocardial repolarization supports the development and maintenance of life-threatening arrhythmias. Current noninvasive approaches for detecting substrates with increased dispersion based on ECG measures (eg, QT dispersion) have shown limited success and inconsistencies. The companion article shows that, in contrast, epicardial potentials and derived measures reflect local dispersion of repolarization. Here, using a recently developed ECG imaging method, we evaluate the feasibility of noninvasive reconstruction of such epicardial measures from body-surface ECG data. METHODS AND RESULTS: Epicardial potentials were recorded with a 224-electrode sock from an open-chest dog during control, regional warming, cooling, and simultaneous adjacent warming and cooling to induce localized changes in myocardial repolarization and regions of increased dispersion. Body-surface potentials were generated from these epicardial potentials in a human torso model. Realistic geometric errors and measurement noise were added to the torso data, which were then used to noninvasively reconstruct epicardial measures of repolarization dispersion (activation recovery intervals [ARIs] and QRST integrals). Repolarization properties were accurately depicted by ECG imaging, including (1) shortened ARIs and increased QRST integrals over the warmed region, (2) prolonged ARIs and decreased QRST integrals over the cooled region, and (3) high gradients of ARIs and QRST integrals over the adjacent warmed and cooled regions. CONCLUSIONS: ECG imaging can reconstruct repolarization properties accurately and localize areas of increased dispersion of repolarization in the heart noninvasively. Its clinical significance lies in the possibility of noninvasive risk stratification and in guidance and evaluation of therapy.

Noninvasive ECG imaging of electrophysiologically abnormal substrates in infarcted hearts : A model study.

BACKGROUND: Myocardial infarction and subsequent remodeling create substrates with altered electrophysiological (EP) properties that are highly arrhythmogenic. Existing ECG methods cannot always detect the existence of such substrates nor provide any detailed information about their EP characteristics. A noninvasive method with such capabilities is greatly needed for identifying patients at risk of arrhythmias and for guidance and evaluation of therapy. Recently, we developed a noninvasive ECG imaging modality that can reconstruct epicardial EP information from body surface potentials. We extended its application to hearts with structural disease and examined its ability to detect and characterize abnormal EP substrates. METHODS AND RESULTS: Epicardial potentials were recorded with a 490-electrode sock from an open-chest dog. Recordings were obtained from a normal heart and from the same heart 2 hours after left anterior descending coronary artery occlusion and ethanol injection to create an infarct. Body surface potentials were generated from these epicardial potentials in a human torso model. Realistic geometry errors and measurement noise were added to the torso data, which were then used to noninvasively reconstruct epicardial potentials and electrograms (EGMs), with excellent accuracy. EP characteristics associated with the infarct substrate were reconstructed, including (1) a negative region over the infarct, (2) EGMs with large predominant negative deflections (eg, Q-wave EGMs), (3) Q-wave EGMs with superimposed RS deflections reflecting local activation of surviving myocardium within the infarct border zone, (4) reduced magnitudes of EGM negative derivatives, and (5) negative QRS integrals of EGMs over the infarct. CONCLUSIONS: ECG imaging can noninvasively detect and map abnormal EP substrates associated with infarction and structural heart disease.

Noninvasive electrocardiogram imaging of substrate and intramural ventricular tachycardia in infarcted hearts.

OBJECTIVES: The goal of this study was to experimentally evaluate a novel noninvasive electrocardiographic imaging modality during intramural reentrant ventricular tachycardia (VT). BACKGROUND: Myocardial infarction and subsequent remodeling produce abnormal electrophysiologic substrates capable of initiating and maintaining reentrant arrhythmias. Existing noninvasive electrocardiographic methods cannot characterize abnormal electrophysiologic substrates in the heart or the details of associated arrhythmias. A noninvasive method with such capabilities is needed to identify patients at risk of arrhythmias and to guide and evaluate therapy. METHODS: A dog heart with a four-day-old infarction was suspended in a human shaped torso-tank. Measured body surface potentials were used to noninvasively compute epicardial potentials, electrograms and isochrones. Accuracy of reconstruction was evaluated by direct comparison to measured data. Reconstructions were performed during right atrial pacing and nine cycles of VT. RESULTS: Noninvasively reconstructed potential maps, electrograms and isochrones identified: 1) the location of electrophysiologically abnormal infarct substrate; 2) the epicardial activation sequences during the VTs; 3) the locations of epicardial breakthrough sites; and 4) electrophysiologic evidence for activation of the Purkinje system and septum during the reentrant beats. CONCLUSIONS: Electrocardiographic imaging can noninvasively reconstruct electrophysiologic information on the epicardium during VT with intramural reentry, provide information about the location of the intramural components of reentry and image abnormal electrophysiologic substrates associated with infarction.

Plasma carnitine levels in patients receiving home parenteral nutrition.

Patients on long-term home parenteral nutrition (HPN) are known to frequently develop hepatic steatosis or steatohepatitis. The etiology of this steatosis or steatohepatitis is unknown, but carnitine deficiency has been one of the postulated mechanisms. The importance of L-carnitine in hepatic fatty acid oxidation and the steatosis observed in primary and acquired carnitine deficiencies prompted us to determine plasma carnitine levels in 37 patients receiving long-term HPN. Thirteen patients (35%) had low total and free plasma carnitine levels. Fifteen of the 37 HPN patients were matched for age and sex with 15 patients with Crohn's disease who did not require HPN. Mean total and free plasma carnitine values were significantly lower (p less than 0.001) in these 15 HPN patients (32.2 +/- 11.9 and 28.4 +/- 10.8) when compared to Crohn's patients not requiring HPN (49.1 +/- 10.9 and 46.4 +/- 11.5). Associations were not detected between plasma carnitine and clinical or biochemical parameters that might have explained the low values.

A randomized prospective trial comparing a defined formula diet, corticosteroids, and a defined formula diet plus corticosteroids in active Crohn's disease.

Although defined formula diets may be useful for initial episodes of Crohn's disease, the effects of these diets on subsequent attacks of Crohn's disease or in conjunction with corticosteroids are unknown. To evaluate these issues, we studied 27 patients in a randomized prospective trial. Ten patients received only prednisone (group I), nine received only a defined formula diet (Vital HN [high nitrogen]) (group II), and eight received a combination of prednisone and Vital HN (group III). At the time of entry into the study, the groups were similar with respect to age, sex, Crohn's Disease Activity Index, previous and current treatments, anatomic site of disease, and nutritional status. After 1 month of treatment, we noted seven successes (70%) and three failures in group I (prednisone only), three successes (33%) and six failures in group II (Vital HN only), and six successes (75%) and two failures in group III (combination therapy). Four patients randomized to receive only Vital HN were unable or unwilling to tolerate the defined formula diet. Of the five patients who were able to take the defined formula diet for 1 month, however, three (60%) were successfully treated. The patients who received prednisone (groups I and III) responded better than did the patients who received only the defined formula diet. These results may be attributable to the use of a nonelemental diet or the treatment of patients who were not experiencing an initial attack of Crohn's disease or who had previously received corticosteroids. The expensive and often poorly tolerated defined formula diets should not be considered as a substitute for standard therapy with corticosteroids in Crohn's disease.