Technical Aspects of Total Artificial Heart Implantation For Temporary Applications

Temporary use of the Jarvik-7 artificial heart in critically ill patients awaiting transplantation has prevented death in greater than 60% of attempts. Success is very dependent on meticulous surgical technique. Failures in the operating room cascade into enlarging problems postoperatively. Appropriately selected patients implanted without bleeding or fit problems recover quickly and are suitable candidates for transplantation within a few days. Even acute renal failure or pulmonary insufficiency from end-stage cardiac disease rapidly reverses upon restoration of normal hemodynamics. Anticoagulation is mandatory to prevent thromboembolism and continuous heparin plus oral dipyridamole is the most successful regimen to date. Primary intraoperative security of all suture lines or potential bleeding foci is thus essential. Bleeding has been associated with tamponade, pulmonary complications, and transfusion stimulated anti-HLA antibodies which can prevent subsequent transplantation. The length and suturing technique of the aortic conduit are critical. Compression of the mediastinal structures by the device can impede systemic or pulmonary venous return, with disastrous results. Displacement of the blood pumps away from the midline, usually into the pleural space, allows for more room when closing the sternum. The 100 cc blood pump fits best in patients greater than 85 kg, while the 70 cc model can be implanted in patients as small as 50-60 kg.     

Malnutrition and Clinical Outcomes: The Case for Medical Nutrition Therapy

Malnutrition is not a new or a rare problem. In studies involving more than 1,327 hospitalized adult patients, 40% to 55% were found to be either malnourished or at risk for malnutrition, and up to 12% were severely malnourished. Surgical patients with likelihood of malnutrition are two to three times more likely to have minor and major complications as well as increased mortality; and their length of stay can be extended by 90% compared with the stay of well-nourished patients. Hospital charges are reported to be from 35% to 75% higher for malnourished patients than for well-nourished patients. Obtaining data to assess the nutritional status of patients is essential to optimal patient care, especially for patients at high risk for malnutrition. Nutrition assessment can be done with readily available and relatively inexpensive methods. But it is not enough to assess and identify malnutrition. Outcomes are improved and costs are saved only when appropriate intervention follows. This article identifies many well-conducted, published studies that support the findings that health outcomes of malnourished patients can be improved and that overall use of resources can be reduced by nutrition counseling, oral diet and oral supplements, enteral formula delivered via tube, and parenteral nutrition support via central or peripheral line. Early nutrition assessment and appropriate nutrition intervention must be accepted as essential for the delivery of quality health care. Appropriately selected nutrition support can address the problem of malnutrition, improve clinical outcomes, and help reduce the costs of health care. J Am Diet Assoc. 1996; 96:361-366,369.     

Maternal-Fetal Histocompatibility in Intrauterine Growth Retarded and Normal Weight Babies

PROBLEM: To determine whether risk for intrauterine growth retardation (IUGR) is increased in HLA-DQA1 compatible pregnancies. METHOD: Paired maternal and cord blood samples were obtained from 30 IUGR and 31 non-IUGR pregnancies delivered at a university hospital. Samples were typed for eight HLA-DQA1 alleles using 10 sequence-specific oligonucleotide probes. Associations between IUGR and HLA-DQ compatibility status, and other risk factors were examined using logistic regression analysis. RESULTS: HLA-DQ compatibility and history of spontaneous abortion were not individually significant risk factors for IUGR; however, there was an interactive effect between these two factors and IUGR (P = 0.085) that improved the overall fit of the logistic model (P < 0.001). No individual allele was more common in IUGR pregnancies. CONCLUSION: HLA compatibility per se is not associated with sufficient inhibition of fetal growth to result in IUGR as defined. However, in women with a history of spontaneous abortion, HLA compatibility may have an effect.     

Spontaneous Activity in Transgenic Mouse Heart:

Spontaneous Activity in Transgenic Mouse Heart and AT-1 Myocytes. Introduction: We have generated transgenic animals that heritably develop atrial tumors composed of difTerentiated proliferating cardiomyocytes. Experiments were initiated to characterize (he electrical properties of these cells. Methods and Results: We show that the primary atrial tumors are composed of discrete foci that exhibit spontaneous automatic activity. A direct correlation was observed between tumor size and firing rate of these foci. In addition to the primary atrial tumors, we examined the propertie.s of cultured cardiomyocytes isolated from a transplantable transgenic tumor lineage (designated AT-1 cells). Cultured AT-1 cells arc al.so spontaneously automatic. The action potential eontiguration from these preparations is similar to that observed in nontransgenic atrial cardiomyocytes, albeit somewbat more depolarized and of longer duration. As would be expected for cardiomyocytes of atrial origin, the transgenic cardiornyocyte preparations hyperpolarize during muscarinic stimulation due to increased K⁺ conductance mediated by a pertussis toxin sensitive G-protein. Assessment of pbarmacologic blockage of the “i_f” pacemaker current suggests that the automaticity of both transgenic cardiomyocyte preparations may be of novel origin. In this context, the cultured AT-1 cells sbowed spontaneous bebavior that was clearly of cellular origin; this activity was manifest as transient bursts of electrical activity followed by periods of electrical quiescence. this bursting pattern is unusual for normal adult cardiomyocytes, but has been observed in several other cell types. In the primary tumors, automatic behavior may arise from a similar cellular origin or alternatively from a microreentrant phenomena. Conclusion: Primary tumors and AT-1 cells sbow essential atrial Electrophysiology with important novel features.     

A Comparative Double-Blind Trial of Mannitol and Magnesium Citrate/Bisacodyl (MCB)* in the Preparation of Barium Enema Patients

In preparation of the large bowel prior to barium enema a double blind trial of 257 patients was performed comparing a regime of oral mannitol with a regime of magnesium citrate, bisacodyl and a 3 day low residue diet. Faecal residue and the quality of mucosal coating with barium were assessed. No significant differences were found between the sexes or in the mucosal coating. MCB regime was significantly better than the mannitol regime in cleansing of the large bowel, though there is room for improvement with the former.     

Toward a stepped care approach to treating problem drinkers: the predictive utility of within-treatment variables and therapist prognostic ratings

Aims. Cost containment, a central issue in current health planning, encourages the use of brief interventions. Although brief interventions for problem drinkers have proved successful, a portion of such individuals do not change their alcohol use during treatment. Design. within-treatment and 6 months post-treatment). Setting and participants. risk for continued problem drinking, predictors of post-treatment drinking were examined for 212 problem drinkers who presented for treatment in an outpatient treatment clinic. Intervention. completed a brief cognitive behavioral motivational intervention. Measurements. assessment demographic, drinking pattern, severity of dependence and other cognitive variables (e.g. self-efficacy, goal choice) were collected. Within-treatment, drinking pattern and cognitive variables such as self-efficacy and goal choice were again measured. Findings. prognosis ratings contributed significantly to the prediction of outcome even when pre-treatment variables were controlled. However, when within-treatment variables were included in the prediction, variables such as within treatment drinking eliminated the predictive utility of therapist prognosis ratings. This pattern held for both percentage of days abstinent and drinks per drinking day at a 6-month follow-up. Conclusions. is suggested that a stepped care approach based on prediction models that include clients' within-treatment response can be applied to the treatment of problem drinkers who show little initial response to treatment. Repeated measures design (pre-treatment, To identify individuals at All participants At the pre-treatment Regression analyses showed that therapist It     

Pericardial Repair of Endocardial Defect Following Regional Endocardial Resection for Ventricular Tachycardia

Regional endocardial resection is the accepted surgical treatment for sustained monomorphic ventricular tachycardia. In patients requiring extensive endocardial resection, or with large aneurysms involving the interventricular septum, the resulting defect may result in weakened myocardium and, ultimately, ventricular septal defect or ventricular rupture. A new approach for repair of the resulting defect is proposed using an autogenous pericardial patch sutured to normal endocardium and included in the aneurysm repair. This technique was performed in six patients undergoing surgery for drug refractory ventricular tachycardia. All patients had large anterior left ventricular aneurysms with endocardial scar extending onto the septum. The large endocardial defect left after endocardial resection and aneurysmectomy was repaired with a pericardial patch. No intraoperative complications (e.g., suture line bleeding) were observed as a result of this technique. All patients are alive, and five of the six patients no longer have inducible ventricular tachycardia. An improvement in congestive heart failure symptoms at 1-9 months of follow-up was noted following surgery. We conclude that the pericardium can be safely used to cover endocardial defects resulting from regional endocardial resection for sustained ventricular tachycardia.     

The intestinal epithelial stem cell: the mucosal governor

All epithelial cells in the small and large intestine are thought to originate from stem cells located towards the base of the crypts of Lieberkühn. To-date, there are no specific intestinal stem cell markers, hence stem cell properties can only be inferred. A range of experimental techniques have been employed including cell position mapping, radiation regeneration (clonogenic) assays, chimeric and transgenic mice. This review discusses the implications of experiments performed using these techniques in order to deduce the number, location and functional properties of stem cells. Stem cell homeostasis is maintained by cell proliferation and death 'through apoptosis'. The various growth and matrix factors and genes which may control these processes, and be important for stem cell function, are discussed along with their carcinogenic and clinical implications.