Outcomes following liver transplantation for seronegative acute liver failure: experience during a 12-year period with more than 100 patients.

Seronegative hepatitis is a common cause of acute liver failure (ALF) requiring liver transplantation. The primary aim of this study was to examine outcomes following transplantation in this group and to identify factors associated with early (<2 months) mortality. Patients studied were 110 consecutive cases of seronegative ALF transplanted at the Queen Elizabeth Hospital, Birmingham, between January 1992 and January 2004. Univariate analysis of 44 pretransplantation recipient, donor, and operative variables was performed initially to identify factors associated with early posttransplantation mortality. Variables identified as significant or approaching significance were analyzed using stepwise multiple logistic regression analysis. Survival following transplantation for seronegative hepatitis was 83%, 81%, and 73% at 2, 12, and 60 months, respectively. The majority (71%) of deaths occurred within the 1st 2 months and sepsis / multiorgan dysfunction was the most common cause of early death. Univariate analysis revealed 9 variables predicting early death. Subsequent multivariate analysis identified high donor body mass index (BMI; a possible surrogate marker for hepatic steatosis) as the most important predictor of early death (P = .009; odds ratio, 1.2; 95% confidence interval, 1.0-1.3). Recipient age >50 (P = .015; odds ratio, 4.2; 95% confidence interval, 1.3-14.1) and non-Caucasian recipient ethnicity (P = .015; odds ratio, 4.9; 95% confidence interval, 1.2-19.2) were other variables associated with early death on multivariate analysis. This study specifically examined factors that determine the early outcome of transplanted seronegative ALF patients. In conclusion, we found that donor and recipient factors identify patients who have a high chance of early death after transplantation.     

Postoperative nausea and vomiting (PONV) after orthognathic surgery: a retrospective study and literature review.

PURPOSE: Postoperative nausea and vomiting (PONV) is the most common postoperative complication after surgery and general anesthesia. PONV occurs primarily within the first 24 hours and can lead to significant morbidity, delayed hospital discharge, increased hospital costs and perhaps most importantly, poor patient satisfaction. We sought, in this study, to determine the prevalence of PONV and to identify risk factors in patients who underwent orthognathic surgery. PATIENTS AND METHODS: We conducted a retrospective cross-sectional analytic survey of 553 consecutive patients over 14 years of age, who underwent maxillary and/or mandibular osteotomies at Kaiser Permanente Hospital (Oakland, CA), between January 2003 and March 2004. Patient-, anesthesia- and surgery-related factors that were considered to have a possible effect on the prevalence of PONV events were evaluated. RESULTS: A total of 514 patients met the inclusion criteria. Among these patients, 40.08% experienced PONV during the first 24 hours after surgery. The most important predictive factors associated with an increased risk of PONV were female gender, young patients (15 to 25 years old), nonsmoking status, presence of predisposing factors (ie, prior history of motion sickness and/or PONV, vertigo or migraine headaches), use of volatile general anesthetics, maxillary surgery, postoperative pain level (PACU) and the use of postoperative analgesic opioid drugs. We found a directly proportional relationship between the number of risk factors and the prevalence of PONV. CONCLUSION: We found PONV had a high prevalence among patients undergoing orthognathic surgery. Further studies are needed to develop effective protocols for preventing this common and unpleasant problem.     

Measurement of arterial input functions for dynamic susceptibility contrast magnetic resonance imaging using echoplanar images: comparison of physical simulations with in vivo results.

Measurement of the arterial input bolus shape is essential to the quantification of mean transit time and blood flow with dynamic susceptibility contrast (DSC) MRI. Input functions derived from the echoplanar signal intensity within or near arteries are highly nonlinear, yet such input functions are widely used. We employed a physical model for the echoplanar signal intensity from an artery as a function of contrast agent concentration, artery size, and angle to the magnetic field to test approaches for the measurement of the arterial input function. The simulated results confirmed the strong nonlinearity of signal in the neighborhood of vessels. Of the input function measurement methods considered, the simulations suggested that measurement of signal near but not within a large vessel is most accurate, but mean transit times (MTT) calculated with these input functions are highly sensitive to peak bolus concentration. Input functions determined from voxels demonstrating the shortest first moment overestimated the MTT but the measured MTTs were more robust to changes in peak concentration. Characteristics of the measured in vivo input functions were consistent with the simulations. Our results emphasize the important contribution of input function errors to the uncertainty in MTT and blood flow imaging with DSC MRI.     

In vivo MRI of cancer cell fate at the single-cell level in a mouse model of breast cancer metastasis to the brain.

Metastasis (the spread of cancer from a primary tumor to secondary organs) is responsible for most cancer deaths. The ability to follow the fate of a population of tumor cells over time in an experimental animal would provide a powerful new way to monitor the metastatic process. Here we describe a magnetic resonance imaging (MRI) technique that permits the tracking of breast cancer cells in a mouse model of brain metastasis at the single-cell level. Cancer cells that were injected into the left ventricle of the mouse heart and then delivered to the brain were detectable on MR images. This allowed the visualization of the initial delivery and distribution of cells, as well as the growth of tumors from a subset of these cells within the whole intact brain volume. The ability to follow the metastatic process from the single-cell stage through metastatic growth, and to quantify and monitor the presence of solitary undivided cells will facilitate progress in understanding the mechanisms of brain metastasis and tumor dormancy, and the development of therapeutics to treat this disease.     

Regulation of fluid intake in dogs following water deprivation

Whereas water loss in land living animals occurs continuously, water intake takes place discontinuously. At the normal operating set point of plasma osmolality, urine is more concentrated than plasma due to secretion of vasopressin. Thus animals operate around a state of mild dehydration. As water loss occurs, the severity of dehydration and thirst increase in intensity and at some point water intake occurs. Sufficient water is consumed to return plasma osmolality to the normal operating set point. Food intake and water balance are interdependent as food provides the osmoles which determine obligatory renal solute excretion. When dry food with the same osmotic content was substituted for canned food (water content 74%), dogs increased water intake from 24.2 +/- 4.3 to 62.2 +/- 8.8 ml/kg. Urine output and urine osmolality were unchanged, as under conditions of normal hydration, near maximal urine concentration is achieved. Changing water intake is the only available variable to maintain water balance. During water deprivation, the major renal mechanism appears to be natriuresis. In rehydration, satiety mechanisms ensure appropriate water intake and renal sodium conservation restores sodium balance.