Cleaning, disinfection and sterilization of surface prion contamination

BACKGROUND

Prion contamination is a risk during device reprocessing, being difficult to remove and inactivate. Little is known of the combined effects of cleaning, disinfection and sterilization during a typical reprocessing cycle in clinical practice.

AIM

To investigate the combination of cleaning, disinfection and/or sterilization on reducing the risk of surface prion contamination.

METHODS

In vivo test methods were used to study the impact of cleaning alone and cleaning combined with thermal disinfection and high- or low-temperature sterilization processes. A standardized test method, based on contamination of stainless steel wires with high titres of scrapie-infected brain homogenates, was used to determine infectivity reduction.

FINDINGS

Traditional chemical methods of surface decontamination against prions were confirmed to be effective, but extended steam sterilization was more variable. Steam sterilization alone reduced the risk of prion contamination under normal or extended exposure conditions, but did show significant variation. Thermal disinfection had no impact in these studies. Cleaning with certain defined formulations in combination with steam sterilization can be an effective prion decontamination process, in particular with alkaline formulations. Low-temperature, gaseous hydrogen peroxide sterilization was also confirmed to reduce infectivity in the presence and absence of cleaning.

CONCLUSION

Prion decontamination is affected by the full reprocessing cycle used on contaminated surfaces. The correct use of defined cleaning, disinfection and sterilization methods as tested in this report in the scrapie infectivity assay can provide a standard precaution against prion contamination.

Antiangiogenic agents and their promising potential in combined therapy

One of the most promising strategies for treating cancer is the addition of antiangiogenic therapy to therapeutic regimens. Angiogenesis, or the growth of new blood vessels from preexisting vessels, is essential both for the growth of a primary tumor and for successful metastasis. As a result of intense research in this field, a number of antiangiogenic agents have been identified and have demonstrated varying degrees of success in inhibiting the growth of solid tumors and metastases in preclinical and clinical studies. The real potential of antiangiogenic agents for cancer therapy resides in strategic combinations with each other, with chemotherapy, with radiation, and with tumor-targeting agents, such as radioimmunotherapy. Along with this new opportunity to develop synergistic therapy comes the challenging complexities of the physiologic systems regulating angiogenesis. These multifaceted systems could intimidate investigators seeking to take advantage of the potential synergy in combined cancer therapy. To aid in these efforts, this overview of key antiangiogenic agent mechanisms, combination strategies and initial studies of the potential synergy with chemotherapy, radiation and radioimmunotherapy is presented.

Sites of conditional essential fatty acid deficiency in end stage liver disease

BACKGROUND

End stage liver disease (ESLD) is a devastating illness. Its protean manifestations involve many different aspects of disturbed hepatic function. One consequence of ESLD is a decrease in plasma levels of very long chain polyunsaturated fatty acids (VL-PUFAs), particularly arachidonic acid (AA) and docosahexaenoic acid (DHA), the former important for eicosanoid metabolism and the latter for retinal and brain membrane structure. The purpose of this study was to define the VL-PUFA changes in liver disease by comparing plasma and tissue levels of VL-PUFAs in controls to patients with ESLD.

METHODS

Fatty acid profiles from plasma, red blood cell (RBC) membranes, muscle, liver, and fat tissue from ESLD patients undergoing liver transplants were measured and compared with control patients undergoing elective liver resection.

RESULTS

Fatty acid profiles from plasma and RBC membranes showed significant decreases in AA and DHA levels in patients with ESLD compared with controls. However, there were no significant differences in tissue fatty acid composition between ESLD patients and controls.

CONCLUSIONS

ESLD affects the liver's ability to maintain circulating levels of AA and DHA, and thereby presumably RBC membrane levels. However, solid tissues appear not to be affected by ESLD. Although the mechanism for these changes remains to be defined, it is consistent with hepatic impairment of elongation and desaturation to produce VL-PUFA for transport. The present results also suggest that dietary interventions to include preformed VL-PUFA rather than their precursors, linoleic and alpha linolenic acid, would be needed to normalize plasma VL-PUFA levels in patients with ESLD.

Hypocaloric total parenteral nutrition: effectiveness in prevention of hyperglycemia and infectious complications--a randomized clinical trial

OBJECTIVE

To determine whether the frequency rate of hyperglycemia and infectious complications can be reduced by an underfeeding strategy in patients requiring total parenteral nutrition (TPN), without deleterious effects on nitrogen balance.

DESIGN

Prospective, randomized, controlled nonblinded trial.

SETTING

A university-affiliated teaching hospital with a dedicated TPN service.

PATIENTS

TPN was initiated in 40 adult patients and continued for > or =5 days.

INTERVENTION

Two different TPN feeding strategies were compared: hypocaloric feeding (1 L containing 70 g protein and 1000 kcal) and standard weight-based regimen, begun in similar amounts initially, but advanced in increments toward 25 kcal and 1.5 g protein/kg dry (or adjusted ideal) weight.

MEASUREMENTS AND MAIN RESULTS

We evaluated the frequency rate of hyperglycemia, average blood glucose, numbers and types of infections while receiving nutritional support and nitrogen balance after 5 days of TPN. There were significant differences between the quantities of calories, dextrose, fat, and protein provided to the two groups. However, average blood glucose, frequency rate of hyperglycemia, and infection rates (from intravenous catheter, pneumonia, and wound/abdominal collection) were similar in each group. The control group showed a trend toward a higher insulin requirement. Nitrogen balance, only available as a subset, was significantly more negative in the hypocaloric group.

CONCLUSIONS

Provision of TPN to a goal of 25 kcal/kg was not associated with more hyperglycemia or infections than a deliberate underfeeding strategy. A regimen of 1.5 g/kg protein in conjunction with 25 kcal/kg did, however, provide significant nutritional benefit in terms of nitrogen balance in comparison with hypocaloric TPN.

Neovascular targeting with cyclic RGD peptide (cRGDf-ACHA) to enhance delivery of radioimmunotherapy

Radioimmunotherapy (RIT) has been hampered by delivery of only a small fraction of the administered dose of radiolabeled MAb to tumor. A strategy for creating and controlling tumor vascular permeability would enable more effective RIT. The alpha v beta 3 integrin receptor is an appealing target for strategies designed to enhance permeability of tumor vessels because it is highly and preferentially expressed in most tumors. In human tumor mouse models, apoptosis of neovascular endothelial cells has been demonstrated after treatment with alpha v beta 3 antagonists. Since this apoptotic effect could transiently increase permeability of tumor blood vessels, radiolabeled antibodies (MAb) circulating during this period would have increased access to extravascular tumor. To determine if this hypothesis was correct, a pharmacokinetic study of an immunospecific MAb given after an alpha v beta 3 antagonist was performed in nude mice bearing human breast cancer xenografts. The alpha v beta 3 antagonist, cyclic RGD pentapeptide (c-RGDf-ACHA; cyclo arginine glycine aspartic acid D-phenylalanine -1 amino cyclohexane carboxylic acid), inhibits alpha v beta 3 binding to its vitronectin ligand at nanomolar levels. Cyclic RGD peptide (250 micrograms i.p.) given 1 hour before 111In-ChL6 MAb resulted in a 40-50% increase in tumor uptake (concentration), when compared to the control tumor uptake, of MAb 24 hours after administration. When cyclic RGD peptide was given as a continuous infusion (17.5 micrograms/hr) for 1 or 24 hours before 111In-ChL6, tumor uptake of 111In-ChL6 was increased less, and, these data were not statistically different from the control data. There were no differences for any of the groups in the groups in the concentrations of 111In-ChL6 in normal organs or blood when compared to the control group. The results suggest that cyclic RGD peptide provided a temporary, selective increase in tumor vascular permeability, that allowed a larger fraction of the 111In-ChL6 to accumulate in the tumor.

Priming of the neutrophil respiratory burst is species-dependent and involves MAP kinase activation

BACKGROUND

Priming of the neutrophil respiratory burst has been implicated in the pathogenesis of multi-system organ failure (MSOF) after sepsis and trauma. The intracellular signal transduction pathways that mediate priming are unclear.

METHODS

Human, porcine, rabbit, rat, and mouse neutrophils were assayed by luminol-dependent chemiluminescence in whole blood and purified neutrophil preparations. Multiple priming agents and agonists were studied, as was inhibition of priming by the p38 mitogen-activated protein kinase (MAPK) inhibitor SB203580 and the Mek 1/2 inhibitor PD98059.

RESULTS

Priming by tumor necrosis factor alpha (TNF-alpha), interleukin-8 (IL-8), and granulocyte-macrophage colony-stimulating factor (GM-CSF) was significantly inhibited by SB203580, whereas platelet-activating factor (PAF) priming was unaffected. Neither TNF-alpha nor PAF primed polymorphonuclear neutrophils (PMNs) within whole blood for N-formyl-methionyl-leucyl-phenylalanine (f-MLP) activation, in contrast to activation by complement-opsonized zymosan (OPZ) or low-dose phorbolmyristate acetate (PMA). Both TNF-alpha and PAF, however, primed purified neutrophils for f-MLP activation. In contrast to human and porcine PMNs, rabbit, rat, and mouse PMNs could not be primed by TNF-alpha or PAF, regardless of the final agonist.

CONCLUSIONS

Priming of the PMN respiratory burst proceeds through multiple signaling pathways, depending on the particular priming agent and agonist pair. Differences in priming between PMNs in whole blood and purified preparations may be physiologically significant. There is a pronounced species dependency in the ability to prime the neutrophil respiratory burst.

Preclinical evaluation of chimeric L6 antibody for the treatment of Kaposi's sarcoma with radioimmunotherapy

L6 is a murine IgG2a monoclonal antibody with panadenocarcinoma reactivity. Chimeric L6 (ChL6), the variable region of murine L6 combined with a human IgG1 constant region, has been used in clinical trials for the delivery of radioimmunotherapy to patients with breast cancer. AIDS-associated Kaposi's sarcoma (KS), a malignancy of vascular endothelium, may be an excellent candidate for systemic radioimmunotherapy because KS is well vascularized and radioresponsive. Because ChL6 has been noted to bind vascular endothelium, our hypothesis was that ChL6 will recognize and bind KS tumors making this a potentially useful antibody for the treatment of KS with radioimmunotherapy. To test this hypothesis, 4 human KS spindle cell cultures established from cutaneous punch biopsy specimens (KS-MR, KS-NO, KS-JD and KS 6-3E) and one well-characterized human KS cell line (KS Y-1) were assessed for L6 immunoreactivity. All 5 cell cultures were L6 positive by immunohistochemistry. KS Y-1 cells grown as nude mouse xenografts were also L6 positive by immunohistochemistry. Competitive binding assays performed on the KS Y-1 and KS 6-3E cell cultures showed high density and high affinity cell binding. Biodistribution experiments performed on nude mice with KS Y-1 xenografts demonstrate tumor targeting by ChL6. These findings indicate that ChL6 may be a useful antibody for the radioimmunotherapy of KS. Future experiments will assess the therapeutic efficacy of radiolabeled ChL6 with and without concurrent systemic radiosensitizing chemotherapy.

Conditionally essential fatty acid deficiencies in end-stage liver disease

Patients with end-stage liver disease (ESLD) manifest a wide variety of functional abnormalities that lead eventually to their death. Such patients also often have low levels of long-chain polyunsaturated fatty acids (PUFA) of carbon length 20 or greater in plasma total lipids, triacylglycerols, cholesterol esters, and phospholipids. We hypothesize that, due to hepatic damage, there is an impairment in de novo synthesis of very long-chain (20-22) carbon PUFA from their essential fatty acid 18 carbon dietary precursors that normally takes place principally in the liver. This results in a "conditional" essential fatty acid deficiency that may, in fact, be responsible for some of the pathophysiologic effects in ESLD. We propose that direct supplementation with very long-chain PUFA will provide a unique advantage in the correction of this "conditional" essential fatty acid deficiency in patients with ESLD and lead to improvements in their clinical condition.

Paclitaxel (Taxol): an inhibitor of angiogenesis in a highly vascularized transgenic breast cancer

Paclitaxel (Taxol), a promoter of microtubule polymerization and a radiosensitizing agent, is one of the more active anticancer drugs in the current treatment of solid tumors. In this study, we show that paclitaxel possesses an antiangiogenic property associated with a down-regulation of vascular endothelial growth factor (VEGF) in a highly-vascularized transgenic murine breast cancer (Met-1). Paclitaxel, at non-cytotoxic doses of 0, 3 and 6 mg/kg/day, was administered intraperitoneally for 5 days to nude mice bearing the Met-1 breast tumor. Extent of intratumoral angiogenesis, as indicated by microvessel tortuosity and microvessel density, was significantly reduced by paclitaxel in a dose-dependent manner. Paclitaxel also suppressed expression of VEGF in the Met-1 cells transplanted in nude mice or maintained in cell culture. These results indicate that antiangiogenesis associated with a down-regulation of VEGF is an additional mode of action of paclitaxel.

Improving protein therapeutics with sustained-release formulations

Although numerous protein therapeutics have been approved or are in advanced clinical testing, the development of more sophisticated delivery systems for this rapidly expanding class of therapeutic agents has not kept pace. The short in vivo half-lives, the physical and chemical instability, and the low oral bioavailability of proteins currently necessitate their administration by frequent injections of protein solutions. This problem can be overcome by use of injectable depot formulations in which the protein is encapsulated in, and released slowly from, microspheres made of biodegradable polymers. Although the first report of sustained release of a microencapsulated protein was more than 20 years ago, the instability of proteins in these dosage forms has prevented their clinical use. Advances in protein stabilization, however, have allowed development of sustained-release forms of several therapeutic proteins, and clinical testing of a monthly formulation human growth hormone is currently in progress. The obvious advantage of this method of delivery is that the protein is administered less frequently, sometimes at lower overall doses, than when formulated as a solution. More importantly, it can justify commercial development of proteins that, for a variety of reasons, could not be marketed as solution formulations.

Inhibitory avoidance and appetitive learning in aged normal mice: comparison with transgenic mice having elevated plasma growth hormone levels

Groups of 25-month-old ("old") B6C3 hybrid male mice, 6-month-old ("young") normal males, and their age-matched transgenic (TG) siblings overexpressing the bovine growth hormone gene were given an inhibitory avoidance training trial (0.20-mA electric shock, 1.0-s duration). The old B6C3 hybrids and the young TG mice displayed poorer retention (shorter latencies to enter the shock compartment) 24 h and 42 days after training than did the young normal mice. In a subsequent multiple-trial acquisition test, young TG and old normal mice required more trials to reach the criterion of complete inhibition of step-through responding for 300 s than did young normal mice. Young normal and young TG mice did not differ in trials to extinction, but TG mice met the extinction criterion sooner than did old normal mice, suggesting poorer longterm retention. In tests of T-maze appetitive learning, young normal, old normal, and young TG mice did not differ in acquisition or 24-h retention. Contrary to expectation, TG mice acquired T-maze reversal learning in fewer trials than did young normal or old normal mice. The TG and young normal mice did not differ in retention when retested 44 days after initial training, but old normal mice showed poorer retention than did the young normals. Results of locomotor activity and shock response tests suggested that learning impairments were not due to differences in locomotor activity or shock response thresholds in these animals. Tests in an elevated plus maze indicated that young TG mice were less anxious in a novel environment than their normal siblings, which may contribute to their impaired inhibitory avoidance learning. These findings suggest that 6-month-old TG mice overexpressing the bovine growth hormone gene display alterations in inhibitory avoidance (but not appetitive) learning similar to those occurring in 25-month-old normal mice. The neurobiological mechanisms mediating inhibitory avoidance and T-maze appetitive learning in these animals may be largely dissociated.

L-[1-(13)C] Phenylalanine oxidation as a measure of hepatocyte functional capacity in end-stage liver disease

BACKGROUND

Liver disease is associated with impaired metabolism of these amino acids phenylalanine and tyrosine. Decreased metabolism of these amino acids leads to abnormal plasma elevations and impaired clearance rates. We have developed a noninvasive breath test that measures hepatic cytosolic enzyme activity.

METHODS

The rate of hepatic phenylalanine metabolism was quantitatively calculated from the appearance of 13CO2 in the breath using the nonradioactive tracer L-[1-(13)C]phenylalanine.

RESULTS

Normal controls (n = 47) oxidized phenylalanine more than twice that of end-stage liver disease patients (n = 117). Significant differences in the percent of phenylalanine oxidized per hour (mean +/- SEM) were found between controls (7.08% +/- 0.33%, 95% CI: 6.42%-7.74%) and Child Pugh classification patients, class A (4.96% +/- 0.69%, 95% CI: 3.50%-6.42%), class B (2.88% +/- 0.13, 95% CI: 2.39%-3.38%) and class C (1.75% +/- 0.13, 95% CI: 1.50%-2.01%). The phenylalanine breath test score significantly correlated with albumin levels, prothrombin time and total bilirubin.

CONCLUSION

We have demonstrated that phenylalanine oxidation is significantly decreased with end-stage liver disease and is correlated with the best clinical measures of liver disease.

Determinants of plasma concentrations of insulin-like growth factor-I and albumin and their hepatic mRNAs: the role of dietary protein content and tumor necrosis factor in malnourished rats

Protein restriction decreases plasma concentrations of albumin and insulin-like growth factor-I (IGF-I) by reducing their hepatic mRNA levels, whereas protein restriction increases IGF-I binding protein-2 (IGFBP-2) gene expression in the liver. Tumor necrosis factor (TNF), as an inducer of the injury response, decreases plasma albumin concentration and albumin mRNA in the liver. The present study was designed to evaluate the effects of protein repletion and TNF on plasma albumin and IGF-I and their mRNAs and IGFBP-2 mRNA in the liver of protein-restricted rats. After 2 weeks of feeding a 2% casein diet, rats were assigned to four groups according to either being refed with a 2% or 20% casein diet or receiving saline or TNF by intraperitoneal injection (50 microg/kg x d) for 4 days. Plasma IGF-I and albumin were assayed. Hepatic mRNAs of IGF-I, albumin, and IGFBP-2 were determined. Protein repletion increased plasma concentrations of IGF-I and albumin and their mRNA content in the liver, but decreased IGFBP-2 mRNA. TNF did not alter plasma IGF-I concentration but did increase hepatic IGF-I mRNA in protein-repleted animals, and plasma albumin concentration was significantly decreased with unaltered hepatic albumin mRNA. Thus, protein repletion of malnourished rats increased plasma IGF-I and albumin concentrations in association with increased expression of their mRNAs in the liver. However, plasma albumin but not IGF-I decreased following TNF in protein-restricted rats, whereas TNF increased hepatic IGF-I mRNA in protein-repleted rats. Thus, only plasma albumin concentration responds to both principal determinants, diet and injury, in the development of malnutrition.

Injury induces rapid changes in hepatocyte nuclear factor-1: DNA binding

BACKGROUND

Transcriptional regulation in the liver plays a critical role in mediating the acute phase response to injury. The molecular mechanisms driving these transcriptional events, however, are poorly defined in vivo. The liver-specific transcription factor hepatocyte nuclear factor (HNF)-1 binds to the 5' upstream region of many acute phase genes. To explore the connection between injury and transcriptional regulatory mechanisms, we investigated the effect of injury on HNF-1 binding activity.

METHODS

Liver nuclear extracts were prepared from animals after burn or anesthetized sham burn injury. HNF-1 binding activity, affinity, and off rate were assessed by electrophoretic mobility shift analysis.

RESULTS

HNF-1 binding activity decreased by 28% 1 1/2 hours after injury. The dissociation constant for HNF-1 increased from 0.6 nm to 11.8 nm at 1 1/2 hours after burn injury partly because of an increase in off rate for the HNF-1: DNA complex.

CONCLUSIONS

Burn injury leads to a significant decrease in HNF-1 binding activity as a result of decreased affinity of HNF-1 for DNA. These injury-induced alterations in binding of a liver-specific transcription factor for its DNA binding site represent a mechanism for rapidly modulating acute phase gene transcription in vivo.

High-energy, high-protein, oral, liquid, nutrition supplementation in patients with HIV infection: effect on weight status in relation to incidence of secondary infection

OBJECTIVE

to evaluate the use of high-energy, high-protein, oral, liquid, nutrition supplementation and nutrition counseling on the weight status of patients infected with the human immunodeficiency virus (HIV) with and without secondary infections.

DESIGN

Prospective, descriptive, intervention trial. Follow-up clinic visits were scheduled every 1 to 3 weeks for at least 6 weeks to monitor weight, gastrointestinal symptoms, number of supplements consumed, and incidence of secondary infections.

SUBJECTS/SETTING

Community-based, HIV-infected patients, with and without an acquired immunodeficiency syndrome (AIDS) defining illness, who were receiving outpatient medical care at Deaconess Hospital. Twenty-two patients enrolled; however, 4 dropped out and 1 died, so 17 were eligible for evaluation.

INTERVENTION

Dietary counseling consisted of recommendations to consume a high-protein diet (1.5 g/kg ideal body weight); select foods that minimize gastrointestinal complications; and take at least one high-energy, high-protein, oral, liquid, nutrition supplement daily.

MAIN OUTCOME MEASURES

Energy intake from the supplements and weight change over time in relation to whether a secondary infection occurred.

STATISTICAL ANALYSIS

Means, standard deviations, and frequency.

RESULTS

At the time of entry to the study, the patients with preexisting weight loss (16 of 17) were 14+/-8% below their usual body weight. On average, patients consumed 11+/-4 supplements per week for 6+/-3 weeks. The majority (12 of 17) were able to gain or maintain weight. Overall weight change was 1.1+/-2.2 kg. Only 5 of 17 patients lost weight, 4 of whom developed a secondary infection during the study (ie, after enrollment in the study). All of those who developed a secondary infection were classified as having AIDS and had lower mean CD4 counts at baseline than those who did not develop a secondary infection. Although those who developed a secondary infection had a higher incidence of weight loss, their consumption of oral supplements per week was greater than that of those without a secondary infection.

APPLICATIONS/CONCLUSIONS

In patients with HIV infection and in the early stages of AIDS without a secondary infection, weight gain and/or maintenance was achievable with a high-energy, high-protein, oral, liquid, nutrition supplement in conjunction with nutrition counseling. The majority of the patients who developed a secondary infection, however, lost weight despite the use of supplements and counseling. Use of a high-energy, high-protein, oral, liquid, nutrition supplement, with intact nutrients, should be the first-line nutrition treatment for malnourished, HIV-infected patients without secondary infections.

Detection of pelvic recurrence of colorectal carcinoma: prospective, blinded comparison of Tc-99m-IMMU-4 monoclonal antibody scanning and CT

PURPOSE

To prospectively compare the accuracy of imaging with technetium-99m-labeled Fab' fragment of the anti-carcinoembryonic antigen antibody (CEA) IMMU-4 with that of computed tomography (CT) for the detection of pelvic recurrence of colorectal carcinoma.

MATERIALS AND METHODS

In 61 patients, blinded interpretations of both modalities were correlated with surgical-pathologic (n = 23) or clinical and CT follow-up findings (n = 38).

RESULTS

Sensitivity and specificity with antibody scanning alone and combined with CT (79% and 84% vs 83% and 81%, respectively) were not significantly different from those values for CT alone (66% and 97%, respectively). Sensitivity of antibody scanning was greater for recurrences larger than 2 cm (94% vs 55% [P = .02]), serum CEA more than 2.5 ng/mL (91% vs 40% [P = .03]), and combined planar and single photon emission CT antibody scanning compared with planar alone (79% vs 48% [P = .03]), without a significant decrease in specificity.

CONCLUSION

Antibody scanning does not improve on findings at CT alone for recurrent colorectal carcinoma but can help differentiate recurrent tumor from fibrosis.

An educational intervention in the surgical intensive care unit to improve ethical decisions

BACKGROUND

The objective of this study was to determine whether an educational intervention on medical ethics offered during a surgical intensive care unit (SICU) rotation could effect meaningful change in a tertiary SICU.

METHODS

A case-based education program was presented weekly to the surgical residents during their SICU rotation. Cases for study were designed to deal with specific ethical issues common to the SICU. Cases were studied with the residents in a group facilitated by a SICU attending physician and a nursing director. The effect of the course was monitored by case review and by the length of stay (LOS) assessment for patients who died in the SICU during 1990, the base year, through 1993.

RESULTS

Discussions of an ethical nature occurred more regularly and earlier during these 4 years as determined by case reviews. For patients who died after being in the SICU a minimum of more than 30 days, a marked decrease occurred in the SICU LOS from 27.8 +/- 3.7 days in 1990 to 15.7 +/- 2.4 days in 1993 (p < 0.05). The number of deaths per year and the average acuity measured by the diagnosis related group score were similar during the 4 years. The LOS in the hospital for dying patients from non-SICU services remained similar during the same time frame. These changes resulted in the dying patients using 1003 SICU days in 1993, down from the 2028 days used in 1990 (p < 0.05).

CONCLUSIONS

We conclude that through offering a clinical ethics program during the SICU portion of the residency training, residents increased knowledge and skill in addressing and integrating practical ethical issues into their surgical resident practice. In addition, patient care directly improved with an associated reduced SICU LOS and reduced cost.

Effects of prostaglandin E2, cholera toxin and 8-bromo-cyclic AMP on lipopolysaccharide-induced gene expression of cytokines in human macrophages

Prostaglandin E2 (PGE2) appears to regulate macrophage cytokine production through the stimulatory GTP-binding protein (Gs protein)-mediated cyclic AMP (cAMP)-dependent transmembrane signal transduction pathway. In this study, we used PGE2, cholera toxin (CT; a direct G alpha s protein stimulator) and 8-bromo-cAMP (a membrane permeable cAMP analogue) to stimulate this pathway, and investigated their influence on cytokine gene expression in lipopolysaccharide (LPS)-activated human macrophages. The mRNA expression for interleukin-1 alpha (IL-1 alpha), IL-1 beta, tumour necrosis factor-alpha (TNF-alpha), IL-6 and IL-8 were determined employing reverse transcription polymerase chain reaction (RT-PCR) using specific primers. We demonstrated that PGE2, CT and 8-bromo-cAMP inhibited the LPS-induced gene activation of TNF-alpha and IL-1 alpha, and had no effect on the gene activation of IL-1 beta and IL-8. Further, our data indicate that PGE2 suppressed the gene activation of IL-6 following LPS stimulation, but neither CT nor 8-bromo-cAMP had an effect. These data suggest that PGE2 alters LPS-stimulated gene activation of only some of the early macrophage cytokines, and does so either by a Gs transmembrane cAMP-dependent or an independent system.

Vascular endothelial growth factor causes endothelial proliferation after vascular injury

Vascular endothelial growth factor was infused into rat carotid arteries for 3 minutes immediately after endothelial denudation by balloon injury. Endothelial proliferation was determined by immunohistochemical labelling of proliferating cell nuclear antigen using Häutchen preparations. The proliferation index, or number of proliferating cells/total cells, measured at 25.5 or 30 hours was markedly increased after infusion of vascular endothelial growth factor. In addition, the total number of proliferating cells increased with increasing doses up to 100 micrograms total dose per infusion. These data indicate that infusion of vascular endothelial growth factor increases endothelial cell proliferation after mechanical denudation injury of the vascular wall.

Rapid modulation of liver-specific transcription factors after injury

BACKGROUND

The reaction to injury is a well-orchestrated physiologic response involving the coordinated actions of multiple integrated systems. It initially occurs at the molecular level and involves changes in gene transcription. We hypothesized that the molecular mechanisms regulating the generation of an inflammatory response are similar to those orchestrating developmental and tissue-specific expression of proteins and, in the case of the acute phase response, occur through manipulation of liver-specific transcription factors and their binding activity.

METHODS

Female BALB/c mice, 7 to 8 weeks old, were subjected to a 15% body surface area burn. Total and polyadenylated liver RNA was isolated, and Northern blot analysis was performed to determine the kinetics of the acute phase proteins albumin and fibrinogen and the liver-specific transcriptional factors CCAAT-enhancer binding protein (C/EBP) alpha, hepatocyte nuclear factor (HNF)-1 alpha, and HNF-4.

RESULTS

Induction of the injury response was shown by an increase in fibrinogen messenger RNA levels and a decrease in albumin mRNA levels. The liver-specific transcription factor C/EBP alpha decreased after injury and remained significantly lower than control at 3 hours. HNF-4 mRNA levels fell more slowly, reaching significantly lower levels at 6 hours and remaining suppressed at 34 hours. HNF-1 alpha showed the most rapid fall in mRNA levels at 30 minutes after injury and remained significantly below control levels at 34 hours.

CONCLUSIONS

The minimal burn injury model leads to the molecular induction of the acute phase response and induces significant and rapid changes in the liver-specific transcription factors C/EBP alpha, HNF-1 alpha, and HNF-4. These changes may represent a mechanism through which the organ-specific response to injury is mediated.

Assessment of the cytokine response in liver donors at the time of organ procurement and association with allograft function after orthotopic transplantation

BACKGROUND

The cause of allograft liver dysfunction after transplantation is unresolved. We tested the hypothesis that human donor liver may be predisposed to ischemia reperfusion injury, and graft dysfunction subsequent to ongoing inflammatory processes during donor hospitalization.

STUDY DESIGN

A prospective study of organ donors and transplant recipients of allograft livers from these donors was conducted. Portal venous, inferior vena caval, and superior vena caval blood samples were obtained from 16 clinical organ donors at the time of organ procurement (one to 12 days post-trauma) to characterize the hepatic cytokine and acute phase protein response, to determine whether or not this response resulted from bacterial or endotoxin translocation to the portal circulation, and to assess whether or not transplant outcome was associated with plasma levels of cytokines in the donor.

RESULTS

In comparison with systemic blood samples from ten healthy persons, all 16 donors exhibited significantly (p < 0.05) elevated plasma concentrations of interleukin-6, interleukin-8, soluble p55 tumor necrosis factor receptor type I (sTNFr-I), and C-reactive protein. No concentration differences existed among portal venous, inferior vena caval, and superior vena caval blood samples for any cytokine or acute phase protein measured. Donor levels of endotoxin, TNF-alpha, soluble intercellular adhesion molecule-1 (sICAM-1), alpha 1-acid glycoprotein, alpha 1-antitrypsin, and haptoglobin were comparable with those in the healthy persons. Bacterial cultures of portal blood were negative. There was no association between the causation of donor trauma and either donor cytokine response or function and quality of the allograft liver after transplantation. Nor could an association between donor cytokine response and either early allograft function (less than 96 hours) or eventual transplant outcome in the recipients be detected.

CONCLUSIONS

These results indicate that, although an ongoing inflammatory response to injury was evident in these donors at the time of organ procurement, there were no apparent adverse effects arising from these inflammatory processes on the function and quality of the donor liver after transplantation. Bacterial translocation does not seem to be a component of the pathogenesis of inflammation. Whether or not the presence of inflammation in the donor alters the metabolic responses of the allograft liver and recipient to transplant operation is unknown.

Alterations in Ca2+ signal transduction in critically ill surgical patients

BACKGROUND

Despite improvements in supportive care and pharmacologic therapies, sepsis and related disorders such as systemic inflammatory response syndrome (SIRS) continue to be a leading cause of death in the intensive care unit. We hypothesized that immune dysfunction in this setting may in part be mediated at the level of early signal transduction in monocytes and neutrophils as manifested by changes in intracellular free Ca2+.

METHODS

Monocytes and neutrophils were isolated from patients in the intensive care unit who met the criteria for SIRS and from normal volunteers. Cells were loaded with the Ca(2+)-sensitive fluorescent dye Indo-1 and stimulated with the chemotactic peptide f-Met-Leu-Phe (fMLP). Changes in intracellular calcium ion concentration were measured by flow cytometry.

RESULTS

Patient monocytes exhibited a decreased Ca2+ flux (43% +/- 3.1%) as compared with normal monocytes (63% +/- 2.5%) (p < 0.05). Patient neutrophils also exhibited a decreased Ca2+ flux in response to fMLP of 58% +/- 3.7% versus 69.3% +/- 3.1% for normal neutrophils (p < 0.05). Incubation of patient cells in normal plasma reversed this dysfunction and showed an improved Ca2+ flux to 60% +/- 2.7% for monocytes and 71% +/- 3.7% for neutrophils (p < 0.05). Conversely, calcium flux was decreased in both normal monocytes (42.3% +/- 3.1%) and normal neutrophils (55.4% +/- 3.8%) after incubation in SIRS patient plasma (p < 0.05). Incubation of normal monocytes and neutrophils in interleukin-1, interleukin-2, interleukin-6, tumor necrosis factor, or lipopolysaccharide did not show a statistically significant alteration in calcium flux in response to fMLP.

CONCLUSIONS

Patients with SIRS exhibit alterations in early signal transduction after stimulation with fMLP in monocytes and neutrophils. This effect appears to be mediated by a soluble factor because the defect in SIRS patient cells can be reversed by incubation in normal plasma and normal cells appear to acquire this defect after incubation in patient plasma. Further studies are underway to identify the factor or factors responsible for this functional defect.

Suicide over 60: the San Diego study

OBJECTIVES

To see if selected clinical factors characterize suicides over the age of 60 differently from younger suicides and to ascertain if those factors characterize female and male suicides over the age of 60 differently.

DESIGN

A group of consecutive suicides aged 60-88 was compared with groups of consecutive suicides aged 31-59 and 16-30. The female suicides aged 60-88 were also compared with the male suicides in that age group. Data were gathered from a variety of informants using a structured interview format.

SETTING

The sample was gathered in San Diego County, California, between November, 1981 and September 1982.

PARTICIPANTS

The sample consisted of 204 consecutive suicides. These included 49 cases aged 60-88, 94 cases aged 31-59, and 61 cases aged 16-30. The older group consisted of 20 females and 29 males.

MEASUREMENTS

Comparisons were made in demographic, diagnostic, and other clinical characteristics.

RESULTS

There were no significant differences between female and male suicides over age 60 on any of the variables examined. Only minor differences were found among the groups in patterns of mental disorders diagnosed. Older suicides were significantly more likely to be married or, if not married, widowed than either of the two younger groups. They were also significantly more likely to be stressed by medical illness. They were significantly less likely to have financial problems as stressors. They were significantly less likely to have talked about suicide or made prior suicide attempts than either of the two younger groups.

CONCLUSIONS

Patterns of certain characteristics of suicides are very similar regardless of age. However, specific age-related differences occur that need to be considered when assessing suicide risk. Older suicides may be harder for clinicians to predict and, therefore, prevent.

Regulation of cytokine mRNA expression in lipopolysaccharide-stimulated human macrophages

One of the responses of the human macrophage to lipopolysaccharide (LPS) is the production of a number of cytokines. The regulation of these cytokines is still not clearly understood. To study this regulation, mRNA levels of interleukin 1 alpha (IL-1 alpha), IL-1 beta, tumor necrosis factor alpha (TNF-alpha), IL-6, granulocyte-macrophage colony-stimulating factor (GM-CSF), and IL-8/neutrophil chemotactic factor were determined in 10-day-old differentiated macrophages following stimulation with a low dose of LPS (0.001 to 10 ng/mL) with use of the polymerase chain reaction. Increased levels of mRNA for IL-8 were detectable after exposure to a very low dose of LPS (0.001 ng/mL) and levels of IL-1 beta and TNF-alpha were detectable only after stimulation with doses of 0.01 ng/mL. The mRNA for IL-8 was detected 30 minutes after the addition of LPS, while those for IL-1 beta and TNF-alpha were only measurable at 1 hour. The mRNAs for IL-1 alpha, IL-6, and GM-CSF were detectable only with a higher dose of lipopolysaccharide and only after a longer exposure time. In addition, the messages for IL-6 and GM-CSF were measurable for a short time, while those of IL-8 and of IL-1 beta were detectable for a longer time. The secretion of TNF-alpha and GM-CSF tightly followed gene activation, and that of IL-6 and IL-8 steadily increased even after the mRNA level of these cytokines returned to baseline. Secretion of IL-1 alpha and IL-1 beta was hardly detected, although their gene activation was obvious. These data indicate that cytokine mRNA levels following lipopolysaccharide stimulation are highly regulated. Individual cytokines show variable patterns of response. These responses are both dose and time dependent and are not necessarily associated with the secretion of protein.

Biliary duct granular cell tumor: a rare but surgically curable benign tumor

Granular [correction of Granulosa] cell tumors are rare benign tumors which may be found throughout the body. Rare cases are isolated within the biliary tree. If completely resected, surgical excision is curative. A case of biliary duct granular [correction of granulosa] cell tumor is presented with review of the world's literature on this topic.

Solid-state NMR assessment of enzyme active center structure under nonaqueous conditions

By using solid-state NMR spectroscopy, the integrity of the active center of alpha-chymotrypsin was investigated under a variety of nonaqueous conditions. Specifically, 13C cross-polarization/magic angle spinning NMR was used to analyze the ability of alpha-chymotrypsin to stabilize a transition state intermediate analog after freezing, drying, and addition of organic solvents (both anhydrous and hydrated) to the resultant powder. Lyophilization disrupted 42 +/- 5% of the active centers; it was determined that this occurred during drying, as opposed to freezing. Seven anhydrous solvents caused 0-50% additional disruption, which occurred immediately on addition of the solvent to the enzyme powder. The extent of structural integrity loss correlated with the solvent hydrophobicity, indicating that further dehydration, i.e. stripping of water retained by the enzyme during lyophilization, was the cause. Enzyme samples prepared with lyoprotecting additives, sucrose and ammonium sulfate, exhibited varying degrees of stabilization against the drying step of lyophilization. Moreover, when hydrophilic anhydrous solvents, which had the highest propensity to strip bound water, were added to the resultant enzyme powders, no additional damage occurred.

Negative regulation of the major histocompatibility complex class I promoter in embryonal carcinoma cells

Transcription of major histocompatibility complex (MHC) class I genes is negatively regulated in undifferentiated F9 mouse embryonal carcinoma cells via the conserved upstream regulatory region. This region contains constitutive enhancers and an inducible enhancer, the interferon consensus sequence (ICS), that is responsible for interferon-induced transcription. A series of mutations in the ICS, but not in the enhancer elements, resulted in an increase in expression of the MHC class I promoter in F9 cells. However, these ICS mutants did not increase promoter activity in F9 cells differentiated after retinoic acid treatment. Results of mobility-shift DNA-binding assays and methylation interference experiments showed that undifferentiated F9 cells contained a factor(s) that bound to a sequence within the 5' and central part of the ICS. This binding site, termed the MHC negative regulatory element (NRE), coincided with the site of mutations that increased promoter activity in F9 cells and was distinct from the element to which interferon-response factors bind. The factor(s) that binds to the MHC NRE was not detected in differentiated F9 cells treated with retinoic acid or in other cells expressing MHC class I genes. Finally, introduction of concatenated, double-stranded NRE oligomers, but not oligomers of unrelated sequences, into F9 cells abolished negative regulation of the MHC class I promoter activity, providing evidence that the NRE binding factor is responsible for repression of the MHC class I genes in F9 cells.

Neonatal induction of a nuclear protein that binds to the c-fos enhancer

The expression of the c-fos gene is transiently induced at birth in most organs in the mouse. To study the basis of this induction we searched for a nuclear factor that binds to the 5' regulatory region of the c-fos gene. Gel mobility shift assays with tissue extracts revealed fast (band I) and slow (band III) migrating bands, which represent factor binding to the c-fos enhancer, termed the serum response element (SRE). Neonatal extracts preferentially elicited band I, with low or undetectable levels of band III, whereas fetal and adult extracts generated predominantly band III, with reduced levels of band I. These results indicate that the SRE-binding activity changes during perinatal development and that the appearance of band I, which coincides with diminution of band III, correlates with neonatal c-fos induction. Methylation interference and competition analyses showed that the neonatal factor (band I) binds to the SRE at a site different from the adult factor (band III). DNA-binding activity of the adult factor, but not the neonatal factor, was sensitive to phosphatase treatment. Furthermore, the adult factor, but not the neonatal factor, shared antigenic specificity with the human serum response factor (SRF) that is expressed in cultured cells irrespective of c-fos gene induction. We conclude that band I in neonates represents a SRE-binding factor that is distinct from the SRF, which may be responsible for the neonatal induction of the c-fos gene. The band III factor was indistinguishable from the SRF in all criteria tested.

Developmental and tissue-specific expression of nuclear proteins that bind the regulatory element of the major histocompatibility complex class I gene

Expression of MHC class I genes varies according to developmental stage and type of tissues. To study the basis of class I gene regulation in tissues in vivo, we examined binding of nuclear proteins to the conserved cis sequence of the murine H-2 gene, class I regulatory element (CRE), which contains two independent factor-binding sites, region I and region II. In gel mobility shift analyses we found that extracts from adult tissues that express class I genes, such as spleen and liver, had binding activity to region I. In contrast, extracts from brain, which does not express class I genes, did not show region I binding activity. In addition, fetal tissues that express class I gene at very low levels, also did not reveal region I binding activity. Binding activity to region I became detectable during the neonatal period when class I gene expression sharply increases. Most of these tissues showed binding activity to region II, irrespective of class I gene expression. Although region II contained a sequence similar to the AP-1 recognition site, AP-1 was not responsible for the region II binding activity detected in this work. These results illustrate a correlation between region I binding activity and developmental and tissue-specific expression of MHC class I genes. The CRE exerts an enhancer-like activity in cultured fibroblasts. We evaluated the significance of each factor binding to CRE. Single 2-bp mutations were introduced into the CRE by site-directed mutagenesis and the ability of each mutant to elicit the enhancer activity was tested in transient CAT assays. A mutation that eliminated region I protein binding greatly impaired enhancer activity. A mutation that eliminated region II binding also caused a lesser but measurable effect. We conclude that region I and region II are both capable of enhancing transcription of the class I gene. These results indicate that in vivo regulation of MHC class I gene expression is mediated by binding of trans-acting factors to the CRE.

Site-specific mutagenesis of the class I regulatory element the Q10 gene allows expression in non-liver tissues

Classical transplantation Ag are found on nearly all cells, whereas Ag encoded by the genes of the Qa/Tla region have a restricted tissue distribution. To investigate the cause of these different patterns of expression, we have compared the regulatory regions of Q10, a Qa region gene that is expressed only in liver, with those of H-2Ld. Gel retardation analysis shows that the nuclear factor (rI) that binds to the inverted repeat (TGGGGATTCCCCA) of the class I regulatory element (CRE) present in H-2Ld and other classical class I genes does not bind to the equivalent region of the Q10 gene. However, the Q10 CRE binds another nuclear factor (rII) that binds to the H-2Ld CRE. The sequence of the Q10 CRE differs from the sequence present in classical class I genes by three nucleotides, two of these changes are within the inverted repeat sequence (TGaGGAcTCCCCA) and disrupt the region of dyad symmetry. We have used site-specific in vitro mutagenesis to individually change these two nucleotides and have investigated the ability of this region to promote transcription with and without these substitutions. A change of either base restores transcriptional activity in chloramphenicol acetyl transferase assays and allows for binding of the rI nuclear factor. These results suggest that the failure of the Q10 CRE to bind the rI nuclear factor may play a role in preventing Q10 expression in tissues other than the liver and fetal yolk sac. Thus, the dichotomy between the widespread tissue expression of classical class I genes and the restricted tissue expression of class I genes of the Qa/Tla region may be due in part to differences in the cis acting regulatory sequences that interact with trans-acting nuclear factors to direct transcription.

Site-specific mutagenesis of the class I regulatory element the Q10 gene allows expression in non-liver tissues

Classical transplantation Ag are found on nearly all cells, whereas Ag encoded by the genes of the Qa/Tla region have a restricted tissue distribution. To investigate the cause of these different patterns of expression, we have compared the regulatory regions of Q10, a Qa region gene that is expressed only in liver, with those of H-2Ld. Gel retardation analysis shows that the nuclear factor (rI) that binds to the inverted repeat (TGGGGATTCCCCA) of the class I regulatory element (CRE) present in H-2Ld and other classical class I genes does not bind to the equivalent region of the Q10 gene. However, the Q10 CRE binds another nuclear factor (rII) that binds to the H-2Ld CRE. The sequence of the Q10 CRE differs from the sequence present in classical class I genes by three nucleotides, two of these changes are within the inverted repeat sequence (TGaGGAcTCCCCA) and disrupt the region of dyad symmetry. We have used site-specific in vitro mutagenesis to individually change these two nucleotides and have investigated the ability of this region to promote transcription with and without these substitutions. A change of either base restores transcriptional activity in chloramphenicol acetyl transferase assays and allows for binding of the rI nuclear factor. These results suggest that the failure of the Q10 CRE to bind the rI nuclear factor may play a role in preventing Q10 expression in tissues other than the liver and fetal yolk sac. Thus, the dichotomy between the widespread tissue expression of classical class I genes and the restricted tissue expression of class I genes of the Qa/Tla region may be due in part to differences in the cis acting regulatory sequences that interact with trans-acting nuclear factors to direct transcription.

Interferon-induced transcription of a major histocompatibility class I gene accompanies binding of inducible nuclear factors to the interferon consensus sequence

Interferon (IFN) induces transcription of major histocompatibility class I genes by way of the conserved cis-acting regulatory element, termed the IFN consensus sequence (ICS). Binding of nuclear factors to the ICS was studied in gel mobility shift assays with the 5' upstream region of the murine H-2Ld gene. We found that the ICS binds a constitutive nuclear factor present in lymphocytes and fibroblasts regardless of IFN treatment. Within 1 hr after IFN treatment, new ICS binding activity was induced, which consisted of at least two binding activities distinguished by their requirement for de novo protein synthesis. Methylation interference and competition experiments showed that both constitutive and induced factors bind to the same approximately equal to 10-base-pair binding site within the ICS. Site-directed mutagenesis of H-2Ld-chloramphenicol acetyltransferase fusion genes showed that mutations in the binding site, but not in other regions of the ICS, abolish transcriptional activation of class I genes by IFN, providing evidence that specific binding of nuclear factors to the ICS is an essential requirement for transcriptional induction. Finally, we show that IFN-inducible genes of various species share a sequence motif that is capable of competing for the nuclear factors identified here. We propose that specific protein binding to the conserved motif represents a basic mechanism of IFN-mediated transcriptional induction of a number of genes.

Binding of multiple nuclear factors to the 5' upstream regulatory element of the murine major histocompatibility class I gene

Transcription of mouse major histocompatibility complex class I genes is controlled by the conserved class I regulatory element (CRE) in the 5' flanking region. The CRE, approximately 40 base pairs long, acts as a negative control element in undifferentiated F9 embryonal carcinoma cells which do not express the major histocompatibility complex genes. The same element, however, acts as a positive control element in cells expressing the genes at high levels. To investigate the molecular basis of the regulatory role of the CRE, we studied the binding of nuclear proteins to the CRE of the H-2Ld gene by gel mobility shift and methylation interference experiments. Nuclear extracts from L fibroblasts and LH8 T lymphocytes revealed three distinct factors that bind discrete sequences within the CRE. The three sequences correspond to the inverted and direct repeats within the CRE. In contrast, F9 extracts exhibited factor binding to only two of the three sequences and lack a major factor detected in the above two cell types. Protein-binding sites within each of the three sequences were identified by methylation interference experiments. These data were in full agreement with results obtained by a competition assay performed with a series of mutant oligonucleotides containing a few nucleotide substitutions in each of the three regions. The results illustrate complex DNA-protein interactions in which several independent proteins bind to overlapping sequences in the CRE in a cell type-specific fashion.

Prophylactic carotid endarterectomy for asymptomatic bruit. A look at cardiac risk

We assessed the influence of preoperative cardiac risk factors in 57 patients undergoing 70 prophylactic carotid endarterectomies (PCE) and found that: (1) 47 (83%) had at least one cardiac risk factor and (2) nine of 15 deaths occurring in the late follow-up period (40 to 120 months) were due to cardiac causes. Perioperatively, one patient sustained a mild stroke. Although the cumulative stroke-free occurrence rate was kept to less than 6% over the five-year period, cardiac morbidity and mortality greatly influenced the quality of life after PCE. Therefore, PCE is suggested only for patients who have minimal preoperative cardiac risk factors or for those patients whose cardiac risk factors can be improved by medical therapy.

The beneficial effect of early excision on clinical response and thymic activity after burn injury

Catabolic response and immunodepression were studied in guinea pigs with scald burns that were excised on day 1 postburn and those that were scald burned but unexcised. Weight gain returned to normal by day 6 in the excised group but remained depressed in burned but unexcised animals whose wounds were untreated, or in unexcised animals whose wounds were treated by topical silver sulfadiazine. Thymic DNA synthesis returned to normal by day 6 in the excised group but remained depressed in the unexcised group. Plasma and thymic-free cortisol returned to normal by day 6 in the excised group but remained markedly elevated in the burned, unexcised animals. These studies indicate early excision and early wound closure reduce the catabolic response and immunodepression of guinea pigs following burn injury.