The impact of diaphragm management on prolonged ventilator support after thoracoabdominal aortic repair

PURPOSE: The relationship of the division of the diaphragm during thoracoabdominal aortic repair to prolonged ventilator support has not been studied. The purpose of this study was (1) to determine whether preservation of diaphragm integrity has a significant effect on postoperative ventilator duration and (2) to elucidate other pulmonary risk factors related to thoracoabdominal aortic surgery and to study the relationship of these factors to the intact diaphragm technique. METHODS:Between February 1991 and January 1997, we repaired 397 descending and thoracoabdominal aortic aneurysms. Descending thoracic aneurysms were not included in the study because their repair does not include the diaphragm. A total of 256 patients participated in this study. The diaphragm was divided in 150 patients and left intact in 106 patients. Examined as potential risk factors were patient demographics, history and physical findings, aneurysm extent, urgency of the procedure, acute dissection, cross-clamp time, homologous and autologous blood product consumption, and adjunctive operative techniques. FEV1 also was considered in the 197 patients for whom preoperative spirometry was available. Prolonged mechanical ventilation was defined as ventilator support for >72 hours. Data were analyzed by univariate contingency table and multiple logistic regression methods. RESULTS: Increasing age (odds ratio [OR], 1.02/y; P <.02), current smoking (OR, 2.6; P <.0008), total cross-clamp time (OR, 1.0/min; P <.008), units packed red blood cells transfused (OR, 1.06/unit; P <.008), and division of the diaphragm (OR, 2.03; P <.02) were significant, independent predictors of prolonged ventilation. Sixty-seven percent of patients (71 of 106) whose diaphragms were preserved were extubated in <72 hours compared with 52% of patients (78 of 150) who underwent diaphragm division (OR, 0.53; P <.02). CONCLUSION: Independently of well known pulmonary risk factors, an intact diaphragm during thoracoabdominal aortic repair results in a higher probability of early ventilator weaning.     

Clinical computed tomographic correlations in children from a group at high risk for schizophrenia

Computed tomography (CT) was performed in 189 individuals: in 44 children of schizophrenic parents (high risk group, HRG), in 39 parents with schizophrenia or with schizophrenic disturbance, in 56 children with schizophrenia, in 50 children with consequences of early organic damages of central nervous system (mental retardation syndrome and generalized tic syndrome). The frequency of CT changes was equal in the mentioned groups but their character was quite different. The widening of brain's liquor system (89.7%), the signs of frontal and temporal atrophia (31%), foci of decreased density of cerebral brain's matter, closer in subcortical ganglia and periventricular zone, and different anomalies of brain were observed in HRG children.     

Biologic glue increases capillary ingrowth after cardiomyoplasty in an ischemic cardiomyopathy model

The authors investigated the multi-step mechanism of healing after cardiomyoplasty, focusing on the process of angiogenesis. The authors contend that enhancement of angiogenesis and prevention of ischemia-reperfusion injuries immediately after muscle mobilization will be effective in improving cardiomyoplasty results. After cardiomyoplasty, autologous biologic glue (ABG) was administered between the latissimus dorsi muscle (LDM) and myocardium. By 2 months, a new pseudo interlayer was present that bridged the gap between the LDM and myocardium. Neovascularization was visible in the form of numerous small capillaries. Marked degeneration of the LDM was noted, possibly caused by muscle ischemia-reperfusion damage after mobilization. Pockets were created of ischemic and nonischemic LDM to test for angiogenesis. One was left free of ABG (control); one received ABG only; one received ABG and pyrrolostatin. Some of the capillaries were large and had erythrocytes inside. biopsy samples showed 9.4 +/- 1.9% of the sample was occupied by blood vessels (compared with 3.6 +/- 0.7% in control muscle). These preliminary studies prove the feasibility of the authors' concept and provide evidence that angiogenesis can accelerate the healing process and provide an organic bridge between the LDM and myocardium after cardiomyoplasty.     

Polymerase chain reaction in the diagnosis of tuberculosis. Comparison of two target sequences for amplification

Amplification of a 340 bp sequence of the 38 kDa protein gene of Mycobacterium tuberculosis by the polymerase chain reaction has been developed. The sensitivity of this PCR was shown to be 10 fg both by agarose gel electrophoresis and Southern blot hybridisation being equivalent to 2-3 organisms and highly specific to M. tuberculosis and excluding even M. tuberculosis H37Ra and Mycobacterium bovis BCG. Sputum samples from patients with pulmonary tuberculosis gave a positivity rate of 45%. PCR was also performed using pt8 and pt9 primers which amplified a 541 bp sequence of IS6110. 41% of the above samples gave positive amplification. Three samples that were positive for 38 kDa sequence were negative for IS6110.     

Tau self-association: stabilization with a chemical cross-linker and modulation by phosphorylation and oxidation state

tau is a major component of paired helical filaments found in the neurofibrillary tangles of Alzheimer's diseased brain. However, the mechanism or mechanisms responsible for the association of tau to form these aggregates remains unknown. In this study, the role of intermolecular disulfide bonds in the formation of higher order oligomers of bovine tau and the human recombinant tau isoform T3 was examined using the chemical cross-linking agent disuccinimidylsuberate (DSS). In addition, the role of phosphorylation and oxidation state on the in vitro self-association of tau was studied using this experimental model. Stabilization of tau-tau interactions with DSS indicated that intermolecular disulfide bonds probably play a predominant role in dimer formation, but the formation of higher order oligomers of tau cannot be attributed to these bonds alone. tau-tau interactions were significantly decreased either by blocking Cys residues or by exposing the tau to a reducing (nitrogen and dithiothreitol), instead of an oxidizing, environment. tau self-association was also significantly decreased by prior phosphorylation with calcium/calmodulin-dependent protein kinase II. Phosphorylation by cyclic AMP-dependent protein kinase or dephosphorylation by alkaline phosphatase did not alter tau self-assembly. These data suggest a role for several factors that may modulate tau self-association in vivo.