Pediatric liver transplantation: patient evaluation and selection, infectious complications, and life-style after transplantation

Liver transplantation is an increasingly accepted treatment for children with end-stage liver disease. Evaluation of the patient and appropriate patient selection for transplantation will become increasingly important issues as more and more children come to transplantation and compete for available organs. Numerous complications occur after transplantation, including infections. We have summarized our experience with bacterial, fungal, and viral infections in these patients and emphasize the need for continued improvement in immune suppressive drugs and regimens to minimize such complications. And finally, information presented on 65 pediatric patients followed 2 to 5 years suggests that, despite numerous complications and often prolonged hospitalization for transplantation, life-style after transplantation appears to be significantly improved.     

Evaluation of prognostic factors in the burned patient]

Mortality predictive factors of burned patients are analyzed in a population of 1929 patients by the statistical method of logistic regression. Among the variables studied (total burn skin area, deep burn area, superficial burn area, age, sex, burn location, preexisting disorders), two only, deep burn area and age, have been retained as predictive factors which, when associated, allow to classify 94.47% of the patients in either survival or death group. The prognosis weight of the deep burn area (SBP) is superior to that of the total burn skin area, yet retained in most previous studies. The superficial burn area, the inhalation injuries and the preexisting disorders are not factors determining prognosis. The F equation = e(-6.0061 + (0.0829*SBP) + (0.0443*%AGE)) resulting of the logistic regression, allows a direct evaluation of the death probability. A simple linear relation can be proposed as score of severity: IG = (2 x %SBP) + age. Below 80, mortality is close to zero, above mortality increases linearly up to 210, reaching 100%. This relation must be handled cautiously when comparing the severity score of two groups of patients, just as any other severity score that uses a linear relation with the burnt area associated or not to age.     

Decreased Streptococcus pneumoniae susceptibility to oral antibiotics among children in rural Vietnam: a community study

Background  

Streptococcus pneumoniae is the most significant bacterial cause of community-acquired pneumonia among children under five years worldwide. Updated resistance information of S. pneumoniae among children is essential to adjust the recommendations for empirical treatment of community-acquired pneumonia, which will have immense implications for local and global health. This study investigated the prevalence of antibiotic resistance in isolated strains of S. pneumoniae and relationship with antibiotic use and demographic factors of children under five in rural Vietnam in 2007.     

Graft-versus-host reactions in the beige mouse. An investigation of the role of host and donor natural killer cells in the pathogenesis of graft-versus-host disease

To investigate the role of natural killer (NK) cells in the induction and pathogenesis of graft-versus-host (GVH) disease, +/beige (+/bg; normal NK cell activity) and beige/beige (bg/bg; deficient NK cell activity) parental C57BL/6 (B6) lymphoid cells were used to induce GVH reactions in either B6 X C3H/Hej +/bg (+/bgF1) or B6 X C3H/HeJF1 bg/bg (bg/bg F1) hybrid mice. When B6 bg/bg parental lymphoid cells (PLC) were injected into bg/bg F1 mice, early splenomegaly, early severe suppression of the plaque-forming cell (PFC) response to sheep red blood cell (SRBC), and only partial suppression of T cell mitogen responses to concanavalin A (Con A) and phytohemagglutin (PHA) were observed on day 12 after GVH induction. In the same GVH combination, slightly augmented NK cytotoxic activity was induced and no GVH-induced moderate-to-severe pathological alterations in the liver and pancreas were observed. When bg/bg PLC were injected into +/bg F1 mice, early splenomegaly and pronounced immunosuppression of the PFC response to SRBC and partial suppression of Con A and PHA responses were observed on day 12 after GVH induction. In this combination (bg/bg----+/bg F1), significant NK cell activity was induced, but no moderate-to-severe histopathological alterations were observed. In contrast, when B6 +/bg PLC were injected into either +/bg F1 or bg/bg F1 hybrids, early splenomegaly, and severe immunosuppression of both the PFC response to SRBC and the T cell mitogen responses to Con A and PHA were observed by day 12--which persisted until day 30 after GVH induction. Furthermore, high NK cell activity was recorded and moderate-to-severe histopathological alterations appeared in both +/bg F1 and bg/bg F1 recipients. These results show that the bg/bg PLC can induce GVH-associated early splenomegaly and immunosuppression of the PFC response to SRBC in both the bg/bg F1 and +/bg F1 hybrids, but that it failed to induce moderate-to-severe histopathological alterations, even though NK cell activity of host origin was activated during GVH reactions. Conversely, when +/bg donor cells were used to induce the GVH reaction, splenomegaly and immunosuppression, as well as moderate-to-severe histopathological lesions were induced. These results suggest that donor NK cells rather than host NK cells play an active role in GVH-associated tissue damage, which in turn contributes to the long-term suppression.     

Endotracheal tube cuff ignited by electrocautery during tracheostomy

A 64-year old female requiring prolonged ventilatory support was scheduled for an elective tracheostomy. Anesthesia consisted of surgical infiltration of 1% lidocaine and supplemental isoflurane. The patient was mechanically ventilated with an FIO2 of 1.0. An incision was made over the third and fourth tracheal rings. Opening the trachea with electrocautery resulted in a large leak around the endotracheal tube. The cuff was visualized through the tracheal incision and noted to be deflated. A small bleeder was coagulated on the tracheal ring. At this point, a flash fire occurred rising about one-inch high through the tracheal incision. The surgeon immediately covered the site with his hand. The anesthetist promptly disconnected the anesthesia circuit and removed the endotracheal tube. The surgeon inserted the tracheostomy tube and ventilation resumed. The fire lasted approximately 1-2 seconds. Dexamethasone 10 mg was administered intravenously. End-tidal CO2 and oxygen saturation levels were unchanged. The endotracheal tube was inspected. Approximately one-third to one-half of the cuff was charred. Proper management of an endotracheal tube fire includes stopping ventilation, disconnecting the oxygen source, removing the endotracheal tube, diagnosing injury, administering short-term steroids, administering antibiotics if indicated, providing ventilation and medical support as necessary and monitoring the patient for at least 24 hours. Extreme caution is necessary when using electrocautery in close proximity to an endotracheal tube. If electrocautery is used in close proximity to an endotracheal tube, an FIO2 of 0.3 or less with helium should be used.     

Expression of interleukin 2 receptors by monocytes from patients with acquired immunodeficiency syndrome and induction of monocyte interleukin 2 receptors by human immunodeficiency virus in vitro.

A population of circulating mononuclear cells from patients with AIDS was identified which expressed interleukin 2 receptors (IL-2R). By dual-fluorescence flow microfluorometry, the patients' IL-2R+ cells were further identified as Leu M3+ monocytes (29.4 +/- 5.2% of the Leu M3+ cells were IL-2R+, n = 15), whereas Leu M3+ monocytes from normal subjects were IL-2R negative (2.0 +/- 0.42%; P less than 0.001). By Northern analysis, monocytes from AIDS patients, but not control subjects, constitutively expressed steady-state levels of IL-2R mRNA. Functionally, the IL-2R+ monocytes were capable of depleting IL-2 from culture supernatants, suggesting a mechanism for the reduced IL-2 levels commonly seen in AIDS patients. IL-2R+ monocytes also expressed increased levels of surface HLA-DR which may favor monocyte T-cell interactions and the transmission of human immunodeficiency virus (HIV). In additional studies, normal monocytes were infected with a macrophage-tropic HIV isolate in vitro and monitored for IL-2R and HLA-DR expression. Within 24-48 h after exposure to HIV in vitro, but before evidence of productive infection, greater than 25% of the monocytes became IL-2R+ with increasing numbers of IL-2R+ cells and HLA-DR levels through day 6. These early signaling effects of HIV could be mimicked by adding purified HIV envelope glycoprotein gp120 to the monocytes. This stimulation of monocytes before or independent of productive infection of the cells by HIV is consistent with in vivo observations of activated and/or abnormal functions by monocytes that do not appear to be infected with HIV in AIDS patients.     

Antagonism of P2Y₁₂ reduces physiological thromboxane levels

Antiplatelet therapy for the management of patients with cardiovascular risks often includes a combination therapy of aspirin and clopidogrel, acting through inhibition of thromboxane generation and blockade of G(i)-coupled P2Y?? receptor, respectively. We hypothesized that ADP acting through P2Y?? regulates physiological thromboxane levels. The serum thromboxane levels in mice (n?=?3) dosed with clopidogrel and prasugrel were decreased by 83.1?±?5.3% and 94.26?±?1.75% respectively compared to untreated mice. Pre-treatment of human blood (n?=?3) ex vivo with active metabolites of clopidogrel or prasugrel led to a reduction in thromboxane levels to 16.3?±?3.2% and 4.9?±?0.8% respectively, compared to untreated human serum. We also evaluated serum thromboxane levels in P2Y receptor null mice (n?=?4). Whereas serum thromboxane levels in P2Y? null mice were similar to those in wild type littermates, those in the P2Y?? null mice were inhibited by 83.15?±?3.8%. Finally, in a pilot study, serum thromboxane levels were reduced by 76.05?±?8.41% in healthy human volunteers (n?=?6) upon dosing with clopidogrel, compared to the levels before dosing. In conclusion, P2Y?? antagonism alone can decrease physiological thromboxane levels. Thus, this study could pave way the for newer/modified treatment regimens for the management of patients with thrombotic complications who are allergic or non-responsive to aspirin.     

Immunoreactivity of calcium binding protein secretagogin in the human hippocampus is restricted to pyramidal neurons

Disturbed calcium homeostasis plays a crucial role in the aetiology of Alzheimer's disease (AD) and the aging process. We evaluated immunoreactivity of secretagogin, a recently cloned calcium binding protein, in hippocampus and adjacent entorhinal cortex of 30 neuropathologically examined post mortem brains (m:f=12:18; mean age, 79.8+/-15.1 years). The study group consisted of 15 cases fulfilling the criteria for high probability of AD according to the NIA-Reagan Institute Criteria and 15 cases with no to medium probability. Sections were incubated with secretagogin-specific antibodies and the number of immunoreactive neurons as well as staining intensities in both neurons and neuropil were assessed. Both cellular and neuropil immunoreactivity were restricted to subiculum and Ammons horn. Cellular immunoreactivity was further restricted to pyramidal neurons and showed a hierarchical distribution: the mean percentage of immunoreactive neurons was highest in sector CA3 (64.41%), followed by CA2 (44.09%), CA4 (34.38%), CA1 (10.9%), and the subiculum (2.92%; P<0.001, except CA2-CA4, P>0.05), while it did not differ significantly between groups with different degrees of AD pathology. The pattern of secretagogin immunoreactivity resembles that of calcium sensor proteins as it is restricted to a subset of neurons and therefore secretagogin could serve highly specialized tasks in neuronal calcium signalling.