Incidence and clinical relevance of bacterial contamination in preservation solution for liver transplantation

OBJECTIVE

Postoperative infection is considered one of the most important causes of morbidity and mortality after liver transplantation. We prospectively studied the incidence and significance of infections in preservation solutions for liver transplantation.

MATERIALS AND METHODS

From March 2007 to March 2008, we cultured the University of Wisconsin preservation solution for 60 consecutive liver transplantations. Fluid samples were obtained at the beginning and at the end of the back table procedure. Our posttransplant infection prophylactic protocol consisted of ampicillin and cefotaxime for 48 hours.

RESULTS

Cultures were positive in 59 patients (98.4%). Seventy-five percent of the isolates were superficial saprophytic flora (SSF; Staphylococcus coagulase negative, Streptococcus viridans, and Corynebacterium), nevertheless in 15 cases (25.1%) we isolated high virulence pathogens (Staphylococcus aureus, Klebsiella, Escherichia coli, Enterobacter, and Pseudomonas aeruginosa). There were neither anaerobic nor fungal isolates. Sixteen patients (36%) from the group with SSF developed postoperative fever, including 12 with negative posttransplant cultures, while 4 patients showed positive cultures for various microorganisms distinct from those isolated from the preservation solution. Five patients (30%) with high virulence pathogens in the preservation solution developed posttransplant fever, although no pathogen was isolated.

CONCLUSIONS

Positive cultures of preservation fluids were observed in 98% of patients, although most of them (75%) were SSF. Microorganisms isolated from posttransplant cultures did not match the ones obtained from the preservation solution. Our results did not support routine culturing of the preservation solution provided that one administrator an adequate posttransplant antibiotic prophylactic regimen.

Acyclovir Delivery Matrices Based on Poly(Ethylene Glycol)/Chitosan Semi-Interpenetrating Networks

Chitosan matrix systems have been studied as potential vehicles for the prolonged release of acyclovir (ACV). The influence of chitosan concentration (from 0.83% to 1.67%) on viscoelastic properties of formulations with and without glyoxal was analyzed. For chitosan-poly(ethylene glycol) 400 formulations loss modulus (G'') are greater than storage modulus (G'). This corresponds to the characteristic behavior of nonstructured systems. When glyoxal was added to the chitosan-poly(ethylene glycol) 400 formulations, gelled matrix was obtained (i.e., G' is higher than G''), except for the lowest chitosan concentration. ACV release rates for the both types of systems, with and without glyoxal, were also determined. The ACV diffusion coefficient values from matrices are less than for the respective formulation without glyoxal and it was found to depend on the crosslink density within the matrices. Viscoelastic parameters, dynamic moduli (G', G''), and complex viscosity (eta*), were correlated with the ACV diffusion coefficients (D). The complex viscosity (eta*) could be used as a parameter of predictive value for the release rate of drugs.

Liver transplantation for hepatocellular carcinoma in cirrhotic patients

A consecutive series of 88 patients underwent transplantation for hepatocellular carcinoma with cirrhosis over a 7-year period. Liver transplantation was indicated because of the tumor in 75 cases (85.2%); tumor was an incidental finding in 13 cases (14.8%). One patient was retransplanted due to primary nonfunction. The perioperative mortality was 4.5%. Tumor recurrence was observed in seven patients (7.95%) with incidental tumor recurrence in one case. As in patients with known primary liver tumors pretransplant, a thorough follow-up is advisable to establish an early diagnosis of recurrence. The actuarial survival for nonincidental hepatocellular carcinoma at 1, 3, and 5 year was 92%, 77%, and 75%, respectively. The differences in actuarial survival between hepatitis C negative and positive hepatocellular carcinoma were not significant (log-rank test P=.27), though there was a clear improvement in results (94%, 85%, and 78% vs 90%, 71%, and 71%), at 1, 3, and 5 years meaning that HCV infection is an important prognostic factor. Although transplantation for HCC has the advantages of removing the tumor and the cirrhotic liver, it remains a controversial topic. In our experience patients showing lesions less than 5 cm or three or fewer lesions experience an equivalent survival to transplanted patients who do not have cancer.

The induction of congenital spinal deformities in mice by maternal carbon monoxide exposure

Carbon monoxide (CO) has been shown to be teratogenic in mice. High altitude hypoxia has also been shown to induce congenital vertebral anomalies in mice. The purpose of this study was to investigate the effect of maternal hypoxia owing to CO exposure and the production of congenital spinal deformities in the offspring. Sixty DBA-1J mice were bred using polygamous timed breeding methods. Pregnant females were exposed to 200, 400, or 600 ppm CO using a custom-designed gas blender system. Seven-hour exposures were performed on day 8.5, 9.5, or 10.5 of the 21-day gestation cycle. The neonates were euthanized at birth; the specimens were fixed, eviscerated, and radiographed. Congenital spinal deformities were observed (wedge, hemi, fused, and missing vertebrae; fused ribs) and were located in all regions of the spine. There was a statistically significant difference in the number of spinal deformities between all groups, with no defects in the controls and a 77% incidence at 600 ppm (p < 0.0001). There was no apparent correlation between the time of exposure and defect location. The most sensitive time of gestation was 9.5 days. We identified an animal model of congenital spinal deformities that compares favorably with the evidence of human congenital spinal deformities in cases of maternal exposure to CO and other gas and chemical fumes.

Programme of education for obese patients. Preliminary results after one year

We have evaluated the effects of a Programme of education for Obese Patients with a duration of 12 hours on weight loss and the modification of other indices for cardiovascular risk in 88 obese patients, during the first year of therapy. The BMI dropped from 33.1 +/- 0.2 Kg/m2 to 31.7 +/- 0.7 (p less than 0.01) and 30.9 +/- 0.7) (p less than 0.01) at 5 and 10 weeks respectively, stabilizing subsequently at 35 and at 55 weeks. This was accompanied by a decrease of the triglycerides levels (141 +/- 9 vs 111 +/- 6 mg/dl; p less than 0.01) and of the total cholesterol/HDL-cholesterol ratio (4.7 +/- 0.3 vs 4.2 +/- 0.12; p less than 0.05), as well as of the values for systolic blood pressure (143 +/- 3 vs 121 +/- 3 mm Hg; p less than 0.05) and diastolic blood pressure 81 +/- 2 vs 64 +/- 1 mm Hg; p less than 0.01) at the end of the study. In terms of OGTT, initially 23 patients were classified as diabetic (BMI 32 +/- 0.9 Kg/m2), 25 presented intolerance to carbohydrates (BMI 34.1 +/- 1.6 Kg/m2) and 40 were normal (BMI 33.2 +/- 1.2 Kg/m2). The weight loss in the first 5 weeks was less in patients with diabetes then in those with carbohydrate intolerance and in the normal patients (2.2 vs 3.7 vs 5.9 Kg; p less than 0.01). From the 10th week on no differences were recorded.(ABSTRACT TRUNCATED AT 250 WORDS)

Colorectal cancer. The bases for a comprehensive follow-up

The purpose of this article was to review the effectiveness of follow-up in patients with colorectal cancer submitted to curative treatment. A comprehensive follow-up involves rational initial management of the primary tumor, knowledge of prognostic factors, selection of the patient to be followed, determination of the time for follow-up, use of the most appropriate tests for early diagnosis of recurrence, and eventual curative treatment. The updated answers to all these questions are given through an extensive review of the world literature and confronted with the authors' experience of eight years of follow-up in a series of 170 colorectal cancer patients treated for cure. Although the future might be more promising, past world experience suggests only a few patients could be saved. It is concluded that there is no place for incomplete and disperse screening tests, and only comprehensive, intensive, and very well-coordinated follow-up programs should be undertaken if better results are hoped to be achieved.

The effect of lactacidemia on regional cerebral blood flow in the newborn dog

The effects of lactacidemia on regional cerebral blood flow (rCBF) were determined in newborn dogs using [14C]iodoantipyrine autoradiography. Measurements of rCBF were made in normoxic, normocarbic, normotensive newborn dogs which were paralyzed and passively ventilated with 70% N2O and 30% O2. In 6 dogs rendered lactacidemic by the intravenous infusion of a 2% unneutralized L-lactic acid solution, arterial lactate concentrations increased by 268% while arterial pH decreased to a mean value of 7.105 +/- 0.051. Lactacidemia also increased mean arterial pCO2 values to 48.3 +/- 4.3 Torr from their original pre-infusion levels of 38.8 +/- 3.1 Torr. Although there were apparent increases in rCBF ranging from 26 to 54% above control levels, upon correction of each region's blood flow values for changes in arterial pCO2, there were no statistically significant differences between rCBF in the control and experimental animals. These results suggest that lactacidemia does not directly alter the cerebral circulation of the normoxic newborn dog.

Regional cerebral blood flow, cerebral blood velocity, and pulsatility index in newborn dogs

A technique employing a Doppler ultrasound probe to measure cerebral blood velocity was used to study the cerebral circulation continuously in 30 newborn mongrel dogs. Utilizing a transfontanelle approach, the probe was maintained in fixed position throughout a given experiment. In 20 animals, changes in systolic, diastolic, and mean cerebral blood velocity during hypo- and hypercarbia were directly correlated (P less than 0.01) with changes in regional cerebral blood flow (rCBF) determined in 12 regions of the brain by the [14C]iodoantipyrine autoradiography technique. In an additional 10 dogs, multiple determinations of systolic, diastolic, and mean blood velocity were made over a wide range of PaCO2 values and found to be directly related to the PaCO2 (P less than 0.001). These data suggest that changes in cerebral blood velocity are closely related to changes in cerebral blood flow. We also calculated the pulsatility index (PI) from the peak systolic and end diastolic velocities and found a poor, but direct (r = 0.28, P less than 0.05) relationship between the PI and PaCO2 rather than the indirect relationship, which has been suggested in published clinical studies. We conclude that the Doppler technique may be valuable in monitoring dynamic events of the neonatal cerebral circulation if a constant probe position is maintained. Our results suggest, however, that the PI is not a reliable index of cerebral vascular resistance.

Selective reduction of blood flow to white matter during hypotension in newborn dogs: a possible mechanism of periventricular leukomalacia

The cerebrovascular response of newborn animals to hypotension has not been defined on a regional basis. Using an autoradiographic technique employing 14C-iodoantipyrine as indicator, we studied the cerebral physiological responses of newborn dogs to hypotension induced by exsanguination or by administration of Escherichia coli endotoxin. Regional cerebral blood flow (rCBF) to all gray matter structures was preserved, even at mean arterial pressures as low as 20 mm Hg. In contrast, rCBF to periventricular and occipital white matter decreased significantly during severe hypotension. The selective hypoperfusion of cerebral white matter during severe hypotension may provide a mechanistic explanation for the pathogenesis of periventricular leukomalacia.

Regional neurohypophyseal blood flow and its control in adult sheep

Regional neurohypophyseal and cerebral blood flows were measured by the radiolabeled microsphere technique in 30 adult sheep under light barbiturate anesthesia. Regional blood flows were determined under basal conditions. The responses of regional blood flow to alterations in arterial PCO2 and to changes in arterial blood pressure wee also determined. In addition, the relationship between regional neurohypophyseal blood flow and neurosecretory activity as judged by plasma arginine vasopressin levels was assessed. Under basal conditions median eminence blood flow averaged 461 ml.100 g-1.min-1 and did not significantly differ from neural lobe blood flow (436 ml.100 g-1.min-1). Blood flow in the neurohypophysis was about 8 times cortical and 16 times white matter blood flow in these animals. Median eminence and neural lobe blood flow proportionately increased far less than regional cortical or white matter blood flow under conditions of hypercarbia. With alteration of arterial blood pressure, regional neurohypophyseal blood flow remained constant beyond the limits of cerebral autoregulation. The neurohypophysis demonstrates a degree of blood flow homeostasis that exceeds that of any other brain area studied. Although the neurohypophysis is a diverticulum of the brain, its vascular system forms a unique functional as well as a unique anatomic unit.

Airway response to inhaled histamine in asymptomatic long-term marijuana smokers

Bronchial challenge with histamine was used to assess bronchial reactivity in asymptomatic individuals who were long-term social smokers of marijuana. Their reactivity was compared to that of nonsmokers and asthmatics. Spirometry results were normal in the marijuana users. There was no significant difference in bronchial reactivity between marijuana smokers and nonsmoking controls, whereas the asthmatics demonstrated the expected hyperreactivity. These observations suggest that customary social use of marijuana may not produce abnormalities in airway function detectable by spirometry or bronchoprovocation.

Rapid, shallow ventilatory pattern during exercise after histamine, bronchopprovocation

The ventilatory response to inhaled histamine sufficient to double specific airway resistance was studied at rest and with exercise in normal subjects. There were no ventilatory alterations at rest but during steady-state exercise the subjects adopted a rapid, shallow breathing pattern. Despite this change and increased resistance over-all ventilation and oxygen consumption were unchanged.