Cardiopulmonary bypass considerations for pediatric patients on the ketogenic diet.

BACKGROUND: There is a population of children with epilepsy that is refractory to anti-epileptic drugs. The ketogenic diet, a high-fat, low-carbohydrate regimen, is one alternative treatment to decrease seizure activity. Special considerations are required for patients on the ketogenic diet undergoing cardiopulmonary bypass (CPB) to prevent exposure to glucose substrates that could alter ketosis, increasing the risk of recurrent seizures. CASE STUDY: A 2-year-old, 9 kilogram male with a history of infantile spasms with intractable epilepsy, trisomy 21 status post tetralogy of Fallot repair, presented to the cardiac operating room for closure of a residual atrial septal defect. All disciplines of the surgical case minimized the use of carbohydrate-containing and contraindicated medications. Changes to the standard protocol and metabolic monitoring ensured the patient maintained ketosis. DISCUSSION: All disciplines within cardiac surgery need to be cognizant of patients on the ketogenic diet and prepare a modified protocol. Future monitoring considerations include thromboelastography, electroencephalography and continuous glucose measurement. Key areas of focus with this patient population in the cardiac surgical theater are to maintain a multidisciplinary approach, alter the required CPB prime components, address cardiac pharmacological concerns and limit any abnormal hematological occurrences.

A systematic evaluation of the core communication skills expected of a perfusionist.

BACKGROUND: The objective of this systematic evaluation was to identify the sentinel standards necessary to obtain a core level of communication required of a clinical perfusionist during cardiopulmonary bypass (CPB). Once these sentinel standards were identified and a core level of communication was established (via four simulated case scenarios), a team of cardiac healthcare professionals was assembled to interpret both the accuracy of response and the speed of response encountered in each case scenario. METHODS: Four simulated case scenarios were utilized in order to replicate the typical patterns of verbal exchange that occur during surgeries using extracorporeal technology. The simulated case scenarios included CPB interactions associated with preparation, initiation, maintenance, termination and post CPB. For all CPB interactions, two variables were measured: accuracy of the perfusionist's response and speed of the perfusionist's response. The cases took place in a controlled setting within an empty operating room at The Children's Hospital of Philadelphia. Four clinical perfusionists each represented the role of the "perfusionist" in all simulated case scenarios. RESULTS: When analyzing the accuracy and speed of the responses, each clinical perfusionist recorded an average score of 96.3% or higher with all case scenarios. Since the clinical perfusionists who participated in the scenarios were primarily pediatric perfusionists, the scores were best during the pediatric case scenario, 99.3% (Case Scenario #4). The lowest scores were captured during Case Scenario #3 (96.3%) which involved a more intense adult patient scenario. CONCLUSION: The systematic evaluation of both response accuracy and response time (presented in various adult and pediatric patient case scenarios) can be beneficial within the realm of perfusion education. Students will be introduced to core communication concepts within the clinical realm. This study supports the idea that simulation and evaluation may ease the transition for students from the didactic to clinical realm in terms of communication. Further studies need to be developed in order to define "standard" CPB communication guidelines for perfusion students.

Alimentação de porcas lactantes com dietas contendo silagem de grãos úmidos de milho e ácido fumárico / Lactating sows fed diets with high moisture corn silage and fumaric acid

Estudou-se o efeito de dietas elaboradas com silagem de grãos úmidos de milho e ácido fumárico sobre os desempenhos de porcas lactantes e suas leitegadas. Foram utilizadas 20 porcas de genética comercial em um delineamento de blocos ao acaso com quatro tratamentos - dieta basal (DB), elaborada a cada 24h; DB + 0,3 por cento de ácido fumárico - (AF); DB + 0,6 por cento AF; e DB + 0,9 por cento de AF, e cinco repetições. As dietas contendo ácido fumárico foram elaboradas a cada 48 horas. O consumo médio diário da dieta das porcas lactantes foi de 7,42kg de matéria natural e não houve diferença (P>0,05) entre os tratamentos. A adição de 0,9 por cento de ácido fumárico às dietas reduziu (P<0,01) em 6 por cento o pH do leite em relação à dieta-basal. A média de ganho diário e a média de peso dos leitões não diferiram (P>0,05) entre os tratamentos. A adição de ácido fumárico às dietas não alterou os desempenhos de porcas lactantes e de suas leitegadas. A adição de ácido fumárico às dietas de lactação elaboradas com silagem de grãos úmidos de milho reduziu o pH do leite e aumentou a frequência de fezes normais dos leitões lactentes.

The effect of lactation diets containing high moisture corn silage and fumaric acid was evaluated on the performance of lactating sows and their piglets. Twenty sows of commercial genetic lines were used in a randomized complete block experimental design with four treatments (basal diet - BD, elaborated each 24h; BD + 0.3 percent fumaric acid - FA; BD + 0.6 percent FA; and BD + 0.9 percent FA) and five replicates. Diets with fumaric acid were elaborated each 48 hours. The average daily feed intake of lactating sows was 7.42kg of natural matter and it was not affected (P>0.05) by treatments. The 0.9 percent fumaric acid addition in diets reduced in 6 percent (P<0.01) the pH of milk compared to basal diet. The average daily weight gain and average weaning live weight of piglets were not influenced (P>0.05) by treatments. The addition of fumaric acid in diets did not alter the performance of lactating sows and piglets. The addition of fumaric acid in lactation diets elaborated with high moisture corn silage increased the normal feces frequency in sucking piglets.

Characteristics associated with the dropout of hypertensive patients followed up in an outpatient referral clinic.

OBJECTIVE: To determine the characteristics associated with the dropout of patients followed up in a Brazilian out patient clinic specializing in hypertension. METHODS: Planned prospective cohort study of patients who were prescribed an antihypertensive treatment after an extensive initial evaluation. The following parameters were analyzed: sex, age, educational level, duration of disease, pressure level used for classifying the patient, previous treatment, physical activity, smoking, alcohol consumption, familial history of hypertension, and lesion in a target organ. RESULTS: We studied 945 hypertensive patients, 533 (56%) of whom dropped out of the follow-up. The mean age was 52.3+/-12.9 years. The highest probabilities of dropout of the follow-up were associated with current smoking, relative risk of 1.46 (1.04-2.06); educational level equal to or below 5 years of schooling, relative risk of 1.52 (1.11-2.08); and hypertension duration below 5 years, relative risk of 1.78 (1.28-2.48). Age increase was associated with a higher probability of follow-up with a relative risk of 0.98 (0.97-0.99). CONCLUSION: We identified a group at risk for dropping out the follow-up, which comprised patients with a lower educational level, a recent diagnosis of hypertension, and who were smokers. We think that measures assuring adherence to treatment should be directed to this group of patients.

Alpha2-macroglobulin does not function as a C3 homologue in the plasma hemolytic system of the American horseshoe crab, Limulus.

A major problem of comparative immunology is the characterization of the internal defense systems that lyse foreign cells, such as bacteria and other microbial pathogens that have gained entry into the body. The plasma cytolytic system of the American horseshoe crab, Limulus polyphemus, is sensitive to treatment with methylamine, which inactivates the abundant plasma defense protein alpha2-macroglobulin. This has been interpreted to mean that alpha2-macroglobulin plays an important role in hemolysis, analogous to the role of complement component C3 of the mammalian complement system (Enghild et al., 1990). Sensitivity to methylamine has been suggested to reflect an evolutionary homology with the plasma cytolytic system of mammals, in which the complement system is inactivated by the reaction of methylamine with complement components C3 and C4. C3, C4 and alpha2-macroglobulin contain an internal thiol ester bond linking cysteinyl and glutamic acid residues and methylamine inactivates all three proteins by reaction with the thiol-esterified glutamic acid. However, we have recently shown that the principal effector of hemolysis in Limulus is the plasma lectin, limulin (Armstrong et al., 1996). In this article we show that native, unreacted alpha2-macroglobulin is not involved directly in hemolysis but instead that methylamine-reacted alpha2-macroglobulin inhibits the hemolytic activity of limulin. Thus the thiol ester proteins alpha2-macroglobulin and C3 operate very differently in the hemolytic systems of Limulus and mammals and are not functionally homologous. Limulus alpha2-macroglobulin functions indirectly in hemolysis: its inactivation yields an inhibitory molecule for limulin-mediated hemolysis.

Expression of the tumor suppressor gene product p16INK4 in benign and malignant melanocytic lesions.

The gene MTS1 encodes p16INK4, an inhibitor of cyclin-dependent kinase 4, and is frequently deleted, mutated, or silenced by promoter methylation in melanoma cells and in the germline of familial melanoma patients. Although MTS1 may thus be the candidate melanoma suppressor gene that maps to chromosome 9p21, it is not clear how dysfunction at that locus temporally relates to melanoma progression. To further test its role in sporadic melanoma, the expression of p16INK4-protein and -mRNA was characterized in melanomas and melanocytic nevi by immunocytochemistry and in situ reverse transcriptase-polymerase chain reaction. Histologic tissue sections were immunolabeled with anti-p16INK4 antibody for 108 melanocytic lesions, including common and atypical nevi, in situ melanomas, primary invasive melanomas, and metastatic tumors. A subset of the lesions was analyzed for expression of p16INK4-mRNA, employing forward and reverse intron-bridging primers for reverse transcriptase-polymerase chain reaction amplification of the transcript corresponding to exons 1 and 2 of MTS1. Strong immunolabeling was detected in the melanocytes of common nevi and of nevi with architectural disorder and cytologic atypia. By digital image analysis, in contrast, labeling intensity decreased significantly and progressively in the melanocytes of in situ, invasive, and metastatic melanomas. Results from the in situ reverse transcriptase-polymerase chain reaction analysis were confirmatory, showing a strong signal in the melanocytic nevi but progressive signal attenuation with increasing stage of melanoma. These data indicate correlation between gradual loss of expression of the MTS1 locus and progression of melanoma, further supporting an emerging role for the gene in the malignant transformation of melanocytes. The failure to demonstrate reduced expression in nevi suggests either that these lesions are not an early stage in melanoma development, in contrast to prevailing assumptions, or that loss of p16INK4 function is not an initiating event in melanocyte transformation.

Alpha 2-macroglobulin-mediated clearance of proteases from the plasma of the American horseshoe crab, Limulus polyphemus.

Because proteases free in the body are damaging to the tissues, animals have evolved various agents for their inactivation and clearance. Mammals, for instance, have a diverse array of active site protease inhibitors in the plasma. In addition, mammals have alpha 2-macroglobulin (alpha 2M), which binds active proteases, and the alpha 2M-protease complex is then cleared from the plasma by a receptor-mediated endocytotic process. alpha 2M is also present in the plasma of many invertebrates, and in the American horseshoe crab, Limulus polyphemus, it is the only protease inhibitor in the plasma. To search for a clearance process for proteases in Limulus, fluorescein isothiocyanate (FITC)-labeled proteins were injected into the blood, and the fluorescence in the plasma and associated with the blood cells was determined. FITC-labeled trypsin was cleared with an initial mixing period (0-10 min) and a rapid clearance period (10-30 min), followed by the reappearance of FITC in the plasma (45-90 min). Before and during the clearance process, the labeled trypsin was associated with a complex having a molecular mass identical to that of Limulus alpha 2M, and that was precipitated by antibodies directed against Limulus alpha 2M. The fluoresceinated material that reappeared in the plasma after 45 min was of low molecular mass (< 10 kDa) and thus appears to have experienced degradation. The clearance of trypsin requires its protease activity, since phenylmethylsulfonyl fluoride-inactivated, FITC-labeled trypsin was cleared only very slowly if at all (t1/2 > 180 min). FITC-labeled, trypsin-reacted Limulus alpha 2M was cleared rapidly from the plasma of Limulus, whereas FITC-labeled, native Limulus alpha 2M persisted undiminished in excess of 400 min. The blood cells of Limulus bound FITC-labeled trypsin-reacted Limulus alpha 2M, and the peak of recovery from the blood cells coincided with the minimum concentration of FITC-labeled protein in the plasma, suggesting that the blood cells participate in the clearance of alpha 2M-protease complex from the plasma. Thus, we have demonstrated the existence of a clearance pathway in Limulus that operates selectively on enzymatically active proteases and have shown that Limulus alpha 2M is the probable agent for protease clearance. This is the first documentation of a protease clearance pathway in invertebrates and represents the first identified physicological function for alpha 2M in invertebrates.

The response of rat liver perisinusoidal lipocytes to polypeptide growth regulator changes with their transdifferentiation into myofibroblast-like cells in culture.

During culture on uncoated plastic wells rat liver perisinusoidal lipocytes change their differentiated phenotype (transdifferentiate) within 1-2 weeks and obtain a myofibroblast-like phenotype (myofibroblast-like cells). This transdifferentiation was documented by morphologic (loss of fat droplets, flat cell shape, cytoplasmic extensions, expression of iso-alpha smooth muscle actin) and biochemical criteria (loss of retinyl-palmitate, enhanced matrix synthesis). Whereas transforming growth factor alpha (TGF alpha) stimulated and transforming growth factor beta (TGF beta 1) inhibited the proliferation of perisinusoidal lipocytes (early culture) these cytokines did not effect the growth of the myofibroblast-like cells. Opposite effects were obtained with platelet-derived growth factor (PDGF) which stimulated the growth of myofibroblast-like cells only. Insulin-like growth factor (IGF1) was mitogenic in both perisinusoidal lipocytes and myofibroblast-like cells, respectively. Furthermore, whereas the expression of the mRNAs of decorin and biglycan was stimulated by TGF beta 1 in perisinusoidal lipocytes, the synthesis of these mRNAs was stimulated in myofibroblast-like cells predominantly by TGF alpha. Similar effects of TGF alpha and TGF beta 1 have been observed on the glycosaminoglycan-([35S]sulfate incorporation) and proteoglycan level ([3H]leucin incorporation into decorin and biglycan). Neither IGF1 and PDGF stimulated glycosaminoglycan synthesis in perisinusoidal lipocytes or in myofibroblast-like cells. The results demonstrate that the effects of the polypeptide growth regulators TGF alpha, TGF beta 1 and PDGF depend on the cell phenotype (stage of cell activation/transdifferentiation) and may be completely different in perisinusoidal lipocytes and its transformed counterpart the myofibroblast-like cells.

Tumor necrosis factor alpha (TNF alpha) and transforming growth factor beta 1 (TGF beta 1) stimulate fibronectin synthesis and the transdifferentiation of fat-storing cells in the rat liver into myofibroblasts.

Transforming growth factor-beta (TGF beta 1) and tumor necrosis factor alpha (TNF alpha) stimulate the transdifferentiation of fat-storing cells (FSC) in the rat liver into highly active and "synthetic" myofibroblast-like cells (MFBIC). This activation has been documented by differential-interference contrast and light microscopy using morphologic criteria (a reduction in the number and size of fat droplets, cell flattening and the development of long cytoplasmic extensions), by the loss of retinyl-palmitate (measured by HPLC) and by the enhanced expression of iso-alpha smooth muscle actin (demonstrated by immunofluorescence microscopy). Furthermore, while cell growth measured by the cell count and DNA content is slightly inhibited by TGF beta 1 (0.81 of the control), the combination of TGF beta 1 with TNF alpha stimulates cell proliferation to 1.44 times of the control. In addition the combination of TGF beta and TNF alpha potentiated the stimulatory effect on fibronectin synthesis (TGF beta alone: 1.4 times control; TNF alpha alone: 2.2 times control; TGF beta plus TNF alpha: 4.7 times control). The total protein synthesis was not altered by TGF beta or TNF alpha. In summary the results obtained identify TGF beta and TNF alpha as mediators stimulating key events in liver fibrogenesis (i.e. FSC proliferation, FSC transdifferentiation into MFBIC, and fibronectin synthesis).

The role of thrombocytes in liver fibrogenesis: effects of platelet lysate and thrombocyte-derived growth factors on the mitogenic activity and glycosaminoglycan synthesis of cultured rat liver fat storing cells.

A central problem in the study of the pathogenesis of liver fibrosis (fibrogenesis) is the identification of the cellular sources of the extracellular matrix and the dissection of the molecular mediators stimulating connective tissue synthesis in certain hepatic target cells. In the present study the role of platelets and of some platelet-derived polypeptide growth factors in the proliferation and proteoglycan synthesis of rat liver fat storing cells in culture (the principle connective tissue-producing cell type in liver) was determined. Fat storing cell proliferation was determined by measurement of the DNA-content, and [3H]thymidine- and bromodeoxyuridine-incorporation. Glycosaminoglycan synthesis was determined by the measurement of [35S]sulphate incorporation. Human platelet lysate (0.3 to 2.6 g protein per litre medium) stimulated, in a dose-dependent manner, both the proliferation and glycosaminoglycan synthesis of rat liver fat storing cells kept as a primary culture in Dulbecco's modification of Eagle's medium in the absence of foetal calf serum. More than 70% of the newly synthesized glycosaminoglycans were found in the medium. Among the various thrombocyte-derived polypeptides tested as candidate mediators of the platelet-derived fibrogenic activity, platelet derived growth factor was not effective in enhancing glycosaminoglycan synthesis, and it stimulated the proliferation of fat storing cells only about 2 fold. On the other hand, epidermal growth factor proved to be a stimulus of both processes. Transforming growth factor beta (greater than 10 pmol/l) inhibited foetal calf serum (Dulbecco's modification of Eagle's medium with a fraction of foetal calf serum of 0.1) and epidermal growth factor stimulated proliferation but enhanced the synthesis of sulphated glycosaminoglycans about 2-fold. These results suggest the possible role of transforming growth factor beta as a negative modulator for fat storing cells proliferation but a positive modulator for fat storing cell transformation and extracellular glycosaminoglycan matrix synthesis. Furthermore, our results indicate a cooperation between different hepatic and extrahepatic cell types by paracrine stimulation of fat storing cells. Transforming growth factor beta in combination with epidermal growth factor appear to be candidate mediators of the platelet-derived fibrogenic activity, which stimulates fat storing cells in culture, and might also be effective in vivo during hepatic repair processes following liver injury.