Preliminary results of a liver allocation plan using a continuous medical severity score that de-emphasizes waiting time

Liver allocation remains problematic because current policy prioritizes status 2B or 3 patients by waiting time rather than medical urgency. On February 21, 2000, we implemented a variance to the United Network for Organ Sharing liver allocation policy that redefined status 2A by much more rigid, definable criteria and prioritized status 2B patients by using a continuous medical urgency score based on the Child-Turcotte-Pugh score and other medical conditions. In this system, waiting time is used only to differentiate status 2B candidates with equal medical urgency scores. Comparing the 6-month period (period 1; n = 67) before implementation of this system to the 6-month period after implementation (period 2; n = 75), there was a significant reduction in the number of transplantations performed for patients listed as status 2A (46.3% to 14.7%; P =.002) and an increase in the number of patients listed as status 2B who received transplants (44.8% to 70.7%; P =.10). Most dramatically, there was a 37.1% reduction in overall deaths on the waiting list from 94 deaths in period 1 to 62 deaths in period 2 (P =.005), with the most significant reduction for patients removed from this list at status 2B (52 v 18 patients; P =.04). There were 3 postoperative deaths in each period, with only 1 graft lost in period 2. Status 2B patients with the greatest degree of medical urgency received transplants without multiple peer reviews requesting elevation to 2A status. We conclude that a continuous medical urgency score system allocates donor livers much more fairly to those in medical need and reduces waiting list mortality without sacrificing efficacy.

A novel approach in treating recurrent bilateral hepaticojejunostomy biliary strictures post-liver transplantation: Successful use of Simpson's atherectomy device

Biliary complications occur in 6% to 34% of patients who undergo orthotopic liver transplantation. Strictures at the anastomosis site or elsewhere in the biliary tract are common. These strictures are amenable to interventional radiological and surgical procedures; however, retransplantation is sometimes an inevitable outcome. An 8-year-old boy received combined liver and kidney transplants May 31, 1998. Hepatic artery thrombosis was diagnosed postoperative day 1 and treated with revascularization. The choledochojejunostomy was revised twice and resulted in a high hepaticojejunostomy. Significant strictures on both the right and left hepatic ducts at the anastomosis site were unsuccessfully treated by multiple interventional radiological procedures. The option of retransplantation was seriously explored. Simpson's atherectomy device was used in a novel approach February 24, 1999, and strictures on both ducts were successfully treated. At 1-year postprocedure, the patient has normal liver function with no evidence of recurrence of the strictures. Further experience with this novel technique is required to assess its role in treating biliary strictures post liver transplantation.

B cell receptor-stimulated mitochondrial phospholipase A2 activation and resultant disruption of mitochondrial membrane potential correlate with the induction of apoptosis in WEHI-231 B cells

Cross-linking of the Ag receptors on the immature B cell lymphoma, WEHI-231, leads to growth arrest and apoptosis. We now show that although commitment to such B cell receptor (BCR)-mediated apoptosis correlates with mitochondrial phospholipase A(2) activation, disruption of mitochondrial function, and ATP depletion, it is executed independently of caspase activation. First, we demonstrate a pivotal role for mitochondrial function in determining B cell fate by showing up-regulation of cytosolic phospholipase A(2) expression, induction of mitochondrial phospholipase A(2) activity, arachidonic acid-mediated collapse of mitochondrial transmembrane inner potential (Delta psi(m)), and depletion of cellular ATP under conditions of apoptotic, but not proliferative, signaling via the BCR. Importantly, disruption of Delta psi(m), ATP depletion, and apoptosis can be prevented by rescue signals via CD40 or by Delta psi(m) stabilizers such as antimycin or oligomycin. Second, we show that commitment and postmitochondrial execution of BCR-mediated apoptosis are not dependent on caspase activation by demonstrating that such apoptotic signaling does not induce release of cytochrome c from the mitochondria or activation of effector caspases, as evidenced by poly(ADP-ribose) polymerase or Bcl-x(L) cleavage. Indeed, apoptotic signaling via the BCR in WEHI-231 B cells does not stimulate the activation of caspase-3 and, consistent with this, BCR-mediated disruption of Delta psi(m) and commitment to apoptosis take place in the presence of caspase inhibitors. In contrast, BCR signaling induces the postmitochondrial activation of cathepsin B, and resultant apoptosis is blocked by the cathepsin B inhibitor, (23,35)trans-epoxysuccinyl-L-leucylamindo-3-methylbutane ethyl ester (EST) suggesting a key role for this executioner protease in Ag receptor-driven apoptosis of WEHI-231 immature B cells.

Syntheses and antimalarial activities of 10-substituted deoxoartemisinins

Two series of 10-substituted deoxoartemisinin derivatives have been synthesized. The first employed the reaction of dihydroartemisinin acetate with several silyl enol ethers in the presence of titanium tetrachloride. The second utilized the reaction of 10-(2-oxoethyl)deoxoartemisinin with several Grignard reagents. The in vitro antimalarial activities of both series were determined against two drug-resistant clones of P. falciparum. The activities of 13 beta and 15 beta were 5-7 times greater than that of artemisinin.

Block of the alpha9 nicotinic receptor by ototoxic aminoglycosides

In the present study, we report that the alpha9 nicotinic acetylcholine receptor (nAChR) expressed in Xenopus laevis oocytes is reversibly blocked by aminoglycoside antibiotics. The aminoglycosides tested blocked the alpha9 nAChR in a concentration-dependent manner with the following rank order of potency: neomycin>gentamicin>streptomycin>amikacin>kanamycin. The antagonistic effect of gentamicin was not overcome by increasing the concentration of acetylcholine (ACh), indicative of a non-competitive type of block. Blockage of ACh-evoked currents by gentamicin was found to be voltage-dependent, being more potent at hyperpolarized than at depolarized holding potentials. Furthermore, gentamicin blockage was dependent upon the extracellular Ca(2+) concentration, shown by the fact that increments in extracellular Ca(2+) significantly reduced the potency of this aminoglycoside to block the alpha9 nAChR. Possible mechanisms of blockage by the aminoglycosides are discussed. The present results suggest that the initial reversible actions of aminoglycosides at the organ of Corti, such as the elimination of the olivocochlear efferent function, are due in part to the interaction with the native alpha9-containing cholinergic receptor of the outer hair cells.

Mixed nicotinic-muscarinic properties of the alpha9 nicotinic cholinergic receptor

The rat alpha9 nicotinic acetylcholine receptor (nAChR) was expressed in Xenopus laevis oocytes and tested for its sensitivity to a wide variety of cholinergic compounds. Acetylcholine (ACh), carbachol, choline and methylcarbachol elicited agonist-evoked currents, giving maximal or near maximal responses. Both the nicotinic agonist suberyldicholine as well as the muscarinic agonists McN-A-343 and methylfurtrethonium behaved as weak partial agonists of the receptor. Most classical cholinergic compounds tested, being either nicotinic (nicotine, epibatidine, cytisine, methyllycaconitine, mecamylamine, dihydro-beta-erythroidine), or muscarinic (muscarine, atropine, gallamine, pilocarpine, bethanechol) agonists and antagonists, blocked the recombinant alpha9 receptor. Block by nicotine, epibatidine, cytisine, methyllycaconitine and atropine was overcome at high ACh concentrations, suggesting a competitive type of block. The present results indicate that alpha9 displays mixed nicotinic-muscarinic features that resemble the ones described for the cholinergic receptor of cochlear outer hair cells (OHCs). We suggest that alpha9 contains the structural determinants responsible for the pharmacological properties of the native receptor.

[Changes in medications acting on the cardiovascular system during hospitalization]

The present study was conducted to assess the extent to which the treatment of patients who take one or more cardiovascular drugs regularly is changed during hospitalisation and over the course of the subsequent two months after release from hospital. In order to elucidate the question more exactly, data was collected on 107 patient after a hospital stay on the internal medicine ward of a university hospital and on 107 patients who had been hospitalised in two non-university hospitals. The average number of changes in medication in patients in the university setting was 2.7 and in patients in the non-university setting it was 2.2. The treatment of patients who were hospitalised for cardiovascular complications was switched more often than that of patients whose circulation was stable at admission. Over the course of the subsequent two months after release, the attending general practitioners (GP) switched the medication at a much lower frequency than the hospitals had done. Within one specific drug class there was no more frequent changes in medication during the hospital stay as afterwards. A drug was discontinued in 107 patients in the university setting and in 124 cases in the two non-university hospitals. The same drug was prescribed again by the treating GP in 30 and 40 patients, respectively, after release. The results of the study show that treatment with drugs that have an effect on the patient's understanding of his illness with regard to its severity may be likely to cause doubts about the effectiveness of the drug and whether the therapeutic decisions that were made by the doctors for medical or other reasons were correct. Therefore, it makes more sense to avoid unnecessary changes in medication whenever possible and only then in unavoidable cases with a clear medical indication.

Management of recurrent hepatitis C after liver transplantation: a concise review

Recurrent hepatitis C infection and subsequent graft failure are increasingly recognized problems after orthotopic liver transplantation. Although many prospective therapeutic, controlled trials in primary hepatitis C disease have been reported, large-scale studies are yet to be performed in patients with posttransplant recurrent hepatitis C after liver transplantation. In this review, we summarize the current literature on the therapeutic approaches for recurrent hepatitis C and discuss the results of published studies on therapy with ribavirin or interferon (IFN) alone and on combination therapy with IFN plus ribavirin. Further, we discuss results of prophylactic approaches to the problem of recurrent hepatitis C after transplant. Finally, we discuss additional aspects of anti-hepatitis C virus therapy after liver transplantation.

Nanoparticle arrays on surfaces for electronic, optical, and sensor applications

Particles in the nanometer size range are attracting increasing attention with the growth of interest in nanotechnological disciplines. Nanoparticles display fascinating electronic and optical properties as a consequence of their dimensions and they may be easily synthesized from a wide range of materials. The dimensions of these particles makes them ideal candidates for the nanoengineering of surfaces and the fabrication of functional nanostructures. In the last five years, much effort has been expended on their organization on surfaces for the construction of functional interfaces. In this review, we address the research that has led to numerous sensing, electronic, optoelectronic, and photoelectronic interfaces, and also take time to cover the synthesis and characterization of nanoparticles and nanoparticle arrays.

Acceptance of an ABO-incompatible mismatched (AB(+) to O(+)) liver allograft with the use of daclizumab and mycophenolate mofetil

Liver allograft survival rates of 50% to 60% are reported in blood group A, group B, group O (ABO)-incompatible mismatched grafts even when aggressive immunosuppressive protocols, including plasmapheresis, OKT(3), cyclophosphamide, cyclosporine, prostaglandin E(1), and steroids, are used. A 59-year-old woman, blood type O(+), required emergency retransplantation posttransplantation day 2 because of primary nonfunction of the liver allograft. A blood type AB(+) allograft was used. Induction immunosuppressive therapy included tacrolimus, mycophenolate mofetil, OKT(3) (muromonab-CD(3)), steroids, and prostaglandin E(1). In addition, plasmapheresis was performed daily for 9 days. OKT(3) and prostaglandin E(1) were also discontinued postoperative day 9. Biopsy-proven acute cellular rejection was diagnosed postoperative day 12 and was treated with double-dose OKT(3) (10 mg) for another 6 days. On the day OKT(3) was discontinued, daclizumab, 60 mg, was administered intravenously. This dose was repeated every 2 weeks for a total of 5 doses. At 1-year follow-up, the patient is doing very well with normal liver function. We are unaware of previous reports of the use of daclizumab and mycophenolate mofetil as part of an immunosuppressive protocol aimed to induce acceptance of ABO-incompatible mismatched liver allografts. Based on our experience with this case, it seems that mycophenolate mofetil is an adequate replacement for cyclophosphamide. We also believe daclizumab provided adequate protection at a critical time. Further experience with both these drugs is required to establish their role in ABO-incompatible mismatched liver allografts.

Cryopreservation of a small number of fresh human testicular spermatozoa and testicular spermatozoa cultured in vitro for 3 days in an empty zona pellucida

It is known that the motility of human testicular sperm can be improved when they are cultured in vitro for a few days. The purpose of this study was to determine whether it is better to freeze human testicular spermatozoa on the day of biopsy (fresh) or after they were cultured for 3 days. A modified, single-sperm freezing technique was used in this study. The study consisted of two parts: (1) ejaculated spermatozoa were used to examine the influence of different concentrations of glycerol and synthetic serum substitute (SSS) on the survival rate after cryopreservation, and (2) the survival rates between cryopreserved fresh testicular spermatozoa (Group 1) and testicular spermatozoa that were cultured for 3 days before freezing (Group 2) were compared. Empty zonae pellucidae were obtained from mouse eggs. Five to 10 motile spermatozoa were selected and injected into an empty zona pellucida. For freezing, the zona pellucida with spermatozoa was transferred into a HEPES-buffered human tubal fluid containing different concentrations of glycerol and kept at room temperature for 10 to 15 minutes, and then loaded into a 0.25-ml-plastic straw. The straws were exposed to liquid nitrogen vapor for 2 hours and then plunged into liquid nitrogen. For thawing, the straws were taken out of liquid nitrogen and placed into a 37 degrees C waterbath for 25 to 30 seconds. There was no statistically significant difference in survival rates between 3% and 10% SSS with different glycerol concentrations. There was no statistically significant difference in the survival rates of spermatozoa between Group 1 and Group 2 after cryopreservation. It appears that in vitro culture of testicular spermatozoa before freezing does not increase survival rate.

Synthesis and antimalarial activities of base-catalyzed adducts of 11-azaartemisinin

A series of N-substituted 11-azaartemisinins were prepared in high yield employing base-catalyzed additions to an amide nitrogen of olefins and terminal acetylenes conjugated with electron withdrawing groups (EWGs). When the terminal acetylene was conjugated with carbomethoxy, N,N-dimethyl amide or carbonyl groups, the E-adducts resulted. A mixture of E- and Z-adducts were obtained when the EWG was a nitrile. In vitro antimalarial activities of each compound were determined against two drug-resistant strains of Plasmodium falciparum. Many of the compounds prepared were several times more active than artemisinin.

The antiviral activity exerted by vaccinia virus on the growth of herpes simplex virus in BS-C-1 cells

The growth of herpes simplex virus type 2 (HSV-2) in BS-C-1 cells, was inhibited following super-infection with vaccinia virus. This inhibition was efficiently induced by both the intracellular mature virus (IMV) form of vaccinia virus and the extracellular enveloped virus (EEV), containing an additional external viral membrane. Treatment of vaccinia IMV with the detergents NP-40, Brij-58 or n-octyl-alpha-D-glucopyranoside, abolished its ability to inhibit the growth of HSV-2. Ultraviolet irradiation of vaccinia virus, that completely inactivated the infectivity of the virus, resulted in partial loss of the capability to inhibit the growth of HSV-2: 16-fold more irradiated virus was needed for the inhibition. Electron microscopy showed that the irradiated vaccinia virus adsorbed and penetrated into the HSV-infected cells but remained morphologically intact within the cells for at least 22 h. When the steps in the growth of HSV affected by the irradiated vaccinia virus were followed, it was found that while the synthesis of HSV DNA was partially decreased, the synthesis of HSV proteins was very strongly inhibited and virus particles were not formed.

Integration of Layered Redox Proteins and Conductive Supports for Bioelectronic Applications

Integration of redox enzymes with an electrode support and formation of an electrical contact between the biocatalysts and the electrode is the fundamental subject of bioelectronics and optobioelectronics. This review addresses the recent advances and the scientific progress in electrically contacted, layered enzyme electrodes, and discusses the future applications of the systems in various bioelectronic devices, for example, amperometric biosensors, sensoric arrays, logic gates, and optical memories. This review presents the methods for the immobilization of redox enzymes on electrodes and discusses the covalent linkage of proteins, the use of supramolecular affinity complexes, and the reconstitution of apo-redox enzymes for the nanoengineering of electrodes with protein monolayers of electrodes with protein monolayers and multilayers. Electrical contact in the layered enzyme electrode is achieved by the application of diffusional electron mediators, such as ferrocene derivatives, ferricyanide, quinones, and bipyridinium salts. Covalent tethering of electron relay units to layered enzyme electrodes, the cross-linking of affinity complexes formed between redox proteins and electrodes functionalized with relay-cofactor units, or surface reconstitution of apo-enzymes on relay-cofactor-functionalized electrodes yield bioelectrocatalytic electrodes. The application of the functionalized electrodes as biosensor devices is addressed and further application of electrically "wired" enzymes as catalytic interfaces in biofuel cells is discussed. The organization of sensor arrays, self-calibrated biosensors, or gated bioelectronic devices requires the microstructuring of biomaterials on solid supports in the form of ordered micro-patterns. For example, light-sensitive layers composed of azides, benzophenone, or diazine derivatives associated with solid supports can be irradiated through masks to enable the patterned covalent linkage of biomaterials to surfaces. Alternatively, patterning of biomaterials can be accomplished by noncovalent interactions (such as in affinity complexes between avidin and a photolabeled biotin, or between an antibody and a photoisomerizable antigen layer) to provide a means of organizing protein microstructures on surfaces. The organization of patterned hydrophilic/hydrophobic domains on surfaces, by using photolithography, stamping, or micromachining methods, allows the selective patterning of surfaces by hydrophobic, noncovalent interactions. Photoactivated layered enzyme electrodes act as light-switchable optobioelectronic systems for the amperometric transduction of recorded photonic information. These systems can act as optical memories, biomolecular amplifiers, or logic gates. The photoswitchable enzyme electrodes are generated by the tethering of photoisomerizable groups to the protein, the reconstitution of apo-enzymes with semisynthetic photoisomerizable cofactor units, or the coupling of photoisomerizable electron relay units.

High calcium permeability and calcium block of the alpha9 nicotinic acetylcholine receptor

At the synapse between olivocochlear efferent fibers and outer hair cells (OHCs) of the cochlea, a non-classical ionotropic cholinergic receptor allows Ca(2+) entry into the hair cell, thus activating a Ca(2+)-sensitive K(+) current which hyperpolarizes the cell's membrane. In the mammalian ear, this leads to a reduction in basilar membrane motion, altering auditory nerve fiber activity and reducing the dynamic range of hearing. The alpha9 nicotinic acetylcholine receptor (nAChR) subunit mediates synaptic transmission between cholinergic olivocochlear fibers and OHCs. Given that Ca(2+) is a key player at this inhibitory synapse, we evaluated the permeability to Ca(2+) of the recombinant alpha9 receptor expressed in Xenopus laevis oocytes and the modulation of its activity by extracellular Ca(2+). Our results show that the alpha9 receptor is highly permeable to Ca(2+) and that this cation potently blocks monovalent currents through this channel (IC(50)=100 microM, at -70 mV) in a voltage-dependent manner. At a Ca(2+) concentration similar to that found in the perilymph bathing the base of the OHCs, approximately 90% of the Na(+) current through the alpha9 receptor is blocked, suggesting that one of the main functions of this channel could be to provide a pathway for Ca(2+) influx.

Sensing of acetylcholine by a tricomponent-enzyme layered electrode using faradaic impedance spectroscopy, cyclic voltammetry, and microgravimetric quartz crystal microbalance transduction methods

A three-enzyme layered assembly on Au electrodes or Au-quartz crystals, consisting of horseradish peroxidase, HRP, choline oxidase, ChO, and acetylcholine esterase, AChE, is used to sense acetylcholine by the HRP-mediated oxidation of 3,3',5,5'-tetramethylbenzidine, TMB (1), by H2O2, and the formation of the insoluble product (2) on the respective transducers. The analyte-substrate, acetylcholine, is hydrolyzed by AChE to choline that is oxidized by ChO and O2 to yield the respective betaine and H2O2. The amounts of generated H2O2 and the resulting insoluble product on the transducers correlate with the concentration of acetylcholine in the samples. The formation of the insoluble product (2) on electrode supports is followed by faradaic impedance spectroscopy that probes the increased interfacial electron-transfer resistance upon the formation of 2, and by cyclic voltammetry that reflects electron-transfer barriers upon the formation of the precipitate. The frequency of the Au-quartz crystal decreases as a result of the accumulation of the insoluble precipitate. The amount of insoluble product formed on the transducers is controlled by the concentration of acetylcholine and by the time interval of biocatalyzed precipitation. The generation of the insoluble product provides a means to amplify the sensing processes. Acetylcholine concentrations corresponding to 1 x 10(-5) M are easily sensed by the different transducers.

The brief abstinence test: voucher-based reinforcement of cocaine abstinence

This study assessed the effectiveness of a brief abstinence reinforcement procedure for initiating cocaine abstinence in methadone maintenance patients. On Monday of the test week, 72 cocaine-abusing methadone patients were offered a $100 voucher if urine samples collected on Wednesday indicated that they had abstained from cocaine across that 2-day period. A patient was considered abstinent and the voucher delivered if the urine benzoylecgonine concentration decreased by 50% from Monday to Wednesday (quantitative criterion) or if the concentration of Wednesday's urine sample was < or = 300 ng/ml. Overall, 79% of study patients showed urinalysis evidence of abstention from cocaine between Monday and Wednesday of the test week. In a subsample with complete data (n = 50), significantly more patients abstained from cocaine from Monday to Wednesday of the test week (84%) than from Monday to Wednesday of the week before (36%) or after (32%) the test week. Furthermore, while almost all patients (94%) decreased their benzoylecgonine concentration from Monday to Wednesday of the test week, significantly fewer patients' benzoylecgonine concentrations decreased from Monday to Wednesday of the week before (56%) or after (48%) the test week. This highly efficacious procedure may have clinical application where reliable abstinence initiation is desired, either on a temporary basis (e.g. sobriety sampling) or at the start of longer-term interventions. It may also be possible to use the brief abstinence test as an experimental model to assess the effects of other therapeutic interventions on abstinence initiation in treatment settings.

Bile acids in xenogeneic ex-vivo liver perfusion: function of xenoperfused livers and compatibility with human bile salts and porcine livers

BACKGROUND

In recent years, hepatic support systems using xenogeneic cells have been developed to support patients in fulminant hepatic failure. The extent to which xenogeneic hepatocytes metabolize and excrete human organic anions is unclear. In these studies we examined the ability of the ex vivo porcine liver to clear human bile acids during extracorporeal liver perfusion (ELP).

METHODS

Four patients with fulminant hepatic failure underwent extracorporeal liver perfusion with 9 porcine livers. The venovenous circuit was designed as previously described (NEJM,1994,331:234) as were the immunologic features (Transplantation 1994,58:1162). Bile from the porcine liver and serum samples were collected hourly during perfusion. Three bile acids (glycocholic, glycodeoxycholic, taurodeoxycholic acid) were selected as markers for human bile and three (glycohyocholic, glycohyodeoxycholic, and glyco-3alpha-hydroxy-6-oxo-5beta-cholanoic acid) for markers of pig bile. Bile acids from both serum and bile were processed and analyzed through high performance liquid chromatography. The Students' t test was used for statistical analysis.

RESULTS

The mean duration of perfusions was 4.1+/-1.5 hr. The mean total bile acid clearance from serum (243+/-44 micromol/h) was similar to the total bile acid biliary excretion (286+/-84 micromol/hr, P = 0.06). After 1 hr of perfusion, bile samples demonstrated a predominance of pig bile salts (65%). After 3 hr of perfusion, human bile acids made up 85% of total biliary bile acids. Pig bile acids appeared in patients' sera after 1 hr of perfusion, and after 3 hr, 35% of serum bile salts were pig-specific.

CONCLUSIONS

Porcine livers perfused with human blood can clear the serum of potentially toxic human bile acids and excrete them into bile. Simultaneously, the percentage of pig-specific bile acids in patient serum increases during xenogeneic perfusion for unknown reasons. The relative hepatic uptake of bile acid from serum is similar to bile acid excretion in bile. Further development of systems using porcine livers or hepatocytes is warranted.

Technologies to minimize blood transfusion in cardiac and orthopedic surgery. Results of a practice variation survey in nine countries. International Study of Peri-operative Transfusion (ISPOT) Investigators

OBJECTIVES

Due to the discovery in the 1980s that blood transfusion can transmit HIV, there has been increased interest in technologies that reduce the amount of allogeneic blood used during and after surgery. These technologies include drugs (aprotinin, tranexamic acid, epsilon-aminocaproic acid, erythropoietin), devices (cell salvage), and techniques (acute hemodilution, predeposited autologous donation). The purpose of this study was to ascertain the degree of practice variation, if any, that exists for eight technologies in nine countries in orthopedic and cardiac surgery.

METHODS

In each country, either all hospitals or a random sample of hospitals with medical/surgical beds were surveyed between 1995 and 1997. Two instruments were used. The first instrument was a postcard that asked recipients whether the technologies were currently being used in their hospital for orthopedic and/or cardiac surgery to reduce perioperative allogeneic transfusion. The second questionnaire elicited information regarding the degree of use both in qualitative and quantitative terms. Data were collected, entered, and analyzed in each country, with summary results submitted to the Canadian coordinating center on a standardized data collection form.

RESULTS

Pharmaceuticals were generally used in a much smaller proportion of hospitals in orthopedic than in cardiac surgery. Aprotinin and tranexamic acid were the drugs most frequently used in cardiac surgery. Nonpharmacological technologies were used to a greater degree than drugs in orthopedic surgery, although there was wide variation among technologies and countries. Acute hemodilution and cell salvage were used in a greater proportion of hospitals for cardiac surgery than orthopedic surgery.

CONCLUSIONS

The results of this survey indicate that there is considerable practice variation in the use of technologies to minimize exposure to perioperative allogeneic transfusion within and between countries.

Co-infection of acyclovir-resistant and acyclovir-sensitive herpes simplex type 2 virus strains in BS-C-1 cells

Co-infection of BS-C-1 cells by the herpes simplex virus type 2 (HSV-2) Curtis strain with its acyclovir (ACV)-resistant mutant (HSV-2-ACV(R)), resulted in a severalfold increase in virus yield, as compared to a single infection. On the other hand, when two viruses (G strain and HSV-2-ACV(R)) belonging to different strains of HSV-2 were involved, their growth was significantly inhibited; the decrease in the titer of the second virus to infect the cells was greater when its infection took place at later times following infection by the first. This inhibition was not due to the shut-off of host cell protein synthesis caused by the first virus, since an HSV-2 mutant which is unable to inhibit the protein synthesis of the host cell was still capable of efficiently inhibiting the growth of the superinfecting virus.

Structure and antimalarial activity of adducts of 11-azaartemisinin with conjugated terminal acetylenes

Several N-substituted 11-azaartemisinins were prepared from 11-azaartemisinin in high yield by the DMAP catalyzed addition of terminal acetylenes conjugated with electron-withdrawing groups. Their antimalarial activities against two drug-resistant strains of Plasmodium falciparum were determined.

Precipitation of an insoluble product on enzyme monolayer electrodes for biosensor applications: characterization by Faradaic impedance spectroscopy, cyclic voltammetry, and microgravimetric quartz crystal microbalance analyses

Precipitation of an insoluble, insulating product on monolayer-functionalized electrodes enables the development of new electrochemical biosensors. Faradaic impedance spectroscopy and cyclic voltammetry are used to probe the electron-transfer resistance at the conductive support upon the accumulation of the insoluble product on the electrode surface. Similarly, microgravimetric quartz crystal microbalance, QCM, analyses were used to assay the formation of the precipitate on the electrode. A horseradish peroxidase, HRP, monolayer electrode is used to analyze H2O2 via the biocatalyzed oxidation of 4-chloro-1-naphthol (1) and the precipitation of the insoluble product (2). A bienzyme-layered electrode consisting of HRP and glucose oxidase, GOx, is used to sense glucose. Biocatalyzed oxidation of glucose by O2, in the presence of GOx, yields H2O2, and the generated hydrogen peroxide effects the formation of the insoluble product (2) in the presence of HRP. The insoluble product accumulated on the electrode, and the extent of the resulting electron-transfer resistance, correlated with the amounts of H2O2 or glucose, and appropriate calibration curves are extracted.

The value of intravenous heme-albumin and plasmapheresis in reducing postoperative complications of orthotopic liver transplantation for erythropoietic protoporphyria

Erythropoietic protoporphyria (EPP) is marked by a deficiency of ferrochelatase, which occurs in all cells and tissues, preventing effective conversion of proto porphyrin IX to heme and thereby blocking effective feedback inhibition of heme synthesis. The major source of the excess protoporphyrin is the bone marrow. Protoporphyrin IX may accumulate, with resultant toxicity chiefly of the marrow, skin, nervous system, and liver. Orthotopic liver transplantation (OLT) is, at present, the only adequate intervention for severe liver compromise secondary to protoporphyrin deposition, but it has been complicated by severe photosensitivity and polyneuropathy. Intravenous heme and plasmapheresis have been proposed but not previously reported as means to reduce the protoporphyrin burden before liver transplantation. We report a man with EPP who underwent preoperative heme-albumin administration and plasmaphereses that led to marked reductions in plasma and erythrocyte protoporphyrin levels. His OLT was uneventful, and he developed neither polyneuropathy nor exacerbation of photosensitivity.