A prospective study in heart and lung transplant recipients correlating persistent Epstein-Barr virus infection with clinical events

BACKGROUND

A 2-year prospective study was set up with 30 cardiothoracic transplant recipients to study Epstein-Barr virus (EBV) infection and immunity and their correlation with clinical events.

METHODS

Regression assays were used to measure EBV-specific cytotoxic T lymphocyte (CTL) function. Tissue culture, immunoblotting, and polymerase chain reaction were used for EBV detection and isolate variation studies.

RESULTS

CTL activity was significantly lower in pretransplant seropositive patients than in healthy controls (P<0.001). CTL response was undetectable in all patients during the first 6 months after transplantation, but returned at levels significantly lower than pretransplant and control levels during the second posttransplant year (P<0.001). Return of CTL function was directly correlated with time of last treated rejection episode (P<0.003) and duration of high plasma levels of cyclosporine (over 400 ng/ml; P<0.003). Significantly higher levels of EBV were detected in peripheral blood during the first 6 months than in pretransplant or control samples (P<0.05). Excretion of EBV in throat washings was significantly lower during the first 3 months when all patients were receiving acyclovir than in pretransplant and control samples (P=0.02). An increase in virus shedding was noted 3-6 months after transplantation, which was significantly higher than in pretransplant patients and controls (P<0.05). Comparison of recipients' and donors' virus isolates in 11 cases showed that seropositive recipients retained their original EBV isolate and did not acquire the donor virus.

CONCLUSIONS

Immunosuppression decreased EBV-specific host immune function, which in turn favored increased EBV load in peripheral blood and increased excretion in the oropharynx. The transfer of donor virus to the seropositive recipients was not observed.

Highlights of the Digital Imaging Network-Picture Archiving and Communications System Project

The Department of Defense issued its requirements for a Digital imaging Network-Picture Archiving and Communications System (DIN-PACS) in a Request for Proposals to industry in January, 1997. The DIN-PACS shall be an open systems network of digital devices designed for the effective acquisition, transmission, display and management of diagnostic imaging studies. This network is primarily based on two international standards, Digital imaging and Communications in Medicine (DICOM) and Health Level 7 (HL7). The DIN-PACS is required to communicate in a bidirectional manner with the Department of Defense standard hospital information system called the Composite Health Care System (CHCS) through an HL7 compliant interface. The DIN-PACS model and its published specifications stress functionality and performance rather than system architecture to allow industry to propose optimal approaches for implementation. This paper discusses the functional requirements of the DIN-PACS in terms of its internal operations as well as its communication with external systems and components. This is a US government work. There are no restrictions on its use.

Successful treatment of severe dysrhythmias in infants with respiratory syncytial virus infections: two cases and a literature review

OBJECTIVES

To describe severe myocardial manifestations in two infants with respiratory syncytial virus infection and to review published literature reporting cardiac involvement in patients with respiratory syncytial virus disease.

DESIGN

Case report and literature review.

SETTING

Tertiary care pediatric intensive care unit (ICU).

PATIENTS

Two infants admitted to the pediatric ICU for dysrhythmias and severe myocardial dysfunction and infected with respiratory syncytial virus.

INTERVENTIONS

Conventional cardiovascular, antidysrhythmic, and respiratory support, as well as extracorporeal membrane oxygenation and high-frequency oscillatory ventilation.

MEASUREMENTS AND MAIN RESULTS

Both patients had respiratory syncytial virus infections and clinical evidence of severe myocarditis, with dysrhythmias, cardiomegaly, and cardiogenic shock. Both infants survived their hospitalizations. To our knowledge, these two patients are the first reported cases of myocarditis in infants with respiratory syncytial virus infection.

CONCLUSIONS

Severe myocardial dysfunction and dysrhythmias may accompany respiratory syncytial virus infection in some infants and may be reversible with aggressive supportive therapy.

Chromosomes 22q11 deletion syndrome: an update and review for the primary pediatrician

Chromosome 22q11 deletion syndrome is a relatively newly described syndrome that encompasses the majority of patients previously felt to have velo-cardio-facial syndrome, DiGeorge syndrome, and conotruncal anomaly face syndrome. The disorder is characterized by a deletion of band 11 on the long arm of chromosome 22 most often recognized by fluorescent in situ hybridization (FISH) techniques. Extensive laboratory investigations are currently ongoing to uncover the specific genes involved and their functions. Phenotypically, individuals present with congenital heart disease, palatal abnormalities, facial dysmorphism, and developmental delay, as well as variable degrees of immunodeficiency, hypocalcemia, and endocrine abnormalities. The primary care physician has an important role in caring for these patients and their families. We review the current state of knowledge regarding chromosome 22q11 deletion syndrome, with an emphasis on the clinical presentation and on prevention and treatment of the known complications associated with this multisystem disorder. Chromosome 22q11 deletion syndrome can be inherited in an autosomal dominant fashion or result from a de novo deletion or translocation. Hence, this syndrome may have significant reproductive risks to affected individuals and families.

Is atelectasis following aortocoronary bypass related to temperature?

OBJECTIVE

To determine the frequency of acute postoperative atelectasis in patients undergoing aortocoronary bypass with either normothermic (warm) or hypothermic (cold) technique.

DESIGN

Prospective, randomized study comparing two groups.

SETTING

University-affiliated hospital.

PATIENTS

Three hundred thirty-one patients (166 cold and 165 warm) undergoing isolated aortocoronary bypass.

MEASUREMENTS

Chest radiographs were obtained preoperatively, on the day of surgery, and subsequently as clinically indicated until discharge from the hospital. Radiologist (blinded to the patient allocation into warm or cold group) scored the atelectasis from 0 to 3 based on its severity. Regression analysis was used to determine if there was any difference in the atelectasis scores between the two groups.

RESULTS

Mean daily postoperative atelectasis scores were not different between the cold and warm groups. The number of patients requiring chest radiographs was similar in both groups. The percent of patients with abnormal chest radiographs was similar in both groups.

CONCLUSION

The temperature of cardioplegia has no effect on the development of atelectasis following aortocoronary bypass, and therefore temperature-related cold injury is not a major cause of atelectasis following this type of surgery.

Steroids inhibit uptake and/or processing but not presentation of antigen by airway dendritic cells

Recent studies from our laboratory indicate that local and (particularly) systemic steroids can modulate the traffic of dendritic cells (DC) through resting and inflamed airway epithelial tissues. The present report focuses upon the T-cell activating properties of DC, which are controlled by granulocyte-macrophage colony-stimulating factor (GM-CSF) signals, and in particular the question of whether the DC-stimulating effects of GM-CSF are susceptible to regulation by steroids. We present evidence that while dexamethasone inhibited GM-CSF-dependent uptake and/or processing of exogenous antigen by DC, it was ineffective in blocking the presentation of preprocessed self antigen to alloreactive T cells in a one-way mixed lymphocyte reaction (MLR). Associated GM-CSF-induced up-regulation of major histocompatability complex (MHC) class II and CTLA4 ligand expression by DC were also unaffected by dexamethasone phosphate (DX), reinforcing the view that the inhibitory effects of steroids on the T-cell activating functions of DC are restricted to steps upstream from presentation of processed antigen to the T-cell receptor (TCR). These findings have potentially important implications in relation to the use of topical steroids in the treatment of atopic asthma, a disease in which local T-cell activation in airway tissue is a key pathogenic factor, and which furthermore is characterized by intense production of GM-CSF within the airway epithelium.

S-glutathiolated hepatocyte proteins and insulin disulfides as substrates for reduction by glutaredoxin, thioredoxin, protein disulfide isomerase, and glutathione

The disulfide-reducing activities of glutaredoxin, thioredoxin, protein disulfide isomerase, glutathione, and cysteine were directly compared with a mixture of hepatocyte 35S-glutathiolated proteins as the substrate. Dethiolation of individual 35S-labeled protein bands from the mixture of hepatocyte proteins was analyzed by SDS-PAGE. All of the 35S-labeled protein bands could be completely dethiolated by glutaredoxin, thioredoxin, protein disulfide isomerase, glutathione, or cysteine. On a molar basis glutaredoxin was over 10 times more effective than either thioredoxin or protein disulfide isomerase. Dethiolation rates of individual proteins varied in minor ways. For example, glutaredoxin dethiolated the 15-, 30-, and 48-kDa protein bands 3 to 4 times faster than the 27-, 28-, and 77-kDa bands. Glutaredoxins from pig liver or from bovine heart had the same specificity and similar activity. The rate of dethiolation by glutathione alone was low compared to the glutaredoxin-catalyzed process, but all 35S-labeled protein bands could be reduced by glutathione, cysteine, or dithiothreitol. Glutathione was clearly more effective than cysteine when these two thiols were compared on the basis of the concentration of thiolate anion available at neutral pH. Therefore, glutathione is a more specific reductant of S-glutathiolated proteins than is cysteine but it is much less effective than glutaredoxin. Since glutaredoxin activity in cells is 10 times higher than the concentration used in these experiments, ample activity is available to account for substantial rates of dethiolation in vivo. Thioredoxin is quite inefficient as a reductant of S-glutathiolated proteins, but it was reasoned that it might first reduce glutaredoxin, which then could reduce the S-glutathiolated protein. A combination of thioredoxin and glutaredoxin was effective. It is proposed that glutaredoxin is the principal agent responsible for protein dethiolation in vivo. The effectiveness of glutaredoxin, thioredoxin, and protein disulfide isomerase as reductants for protein disulfide bonds was examined with insulin as the substrate. Protein disulfide isomerase was very effective and thioredoxin was nearly as effective. Human thioredoxin was similar to Escherichia coli thioredoxin in reactivity and specificity. Glutaredoxin did not facilitate insulin reduction at equal concentrations. Thus, protein disulfide isomerase and thioredoxin are more effective than glutaredoxin as reductants of insulin protein disulfides. The apparent reduction potential of pig liver glutaredoxin (-0.159 +/- 0.004 V) was determined by measuring the amount of reduced glutaredoxin in equilibrium with mixtures of glutathione and glutathione disulfide. Glutaredoxin was a weaker reductant than E. coli thioredoxin (-0.260 V) and was similar to protein disulfide isomerase (-0.11 to -0.19 V). The role of these proteins as disulfide reductants is not determined solely by thermodynamic considerations. A glutathione binding site at the dithiol region of glutaredoxin may be of primary importance for its function in protein dethiolation, while a different specific peptide binding site in thioredoxin may be more suited to certain protein disulfide structures.

beta-mercaptoethanol enhances blastocyst formation rate of bovine in vitro-matured/in vitro-fertilized embryos

The objectives of this research were to determine the effects of beta-mercaptoethanol (beta-ME) and fetal bovine serum (FBS) on in vitro development of bovine embryos derived from oocytes matured and fertilized in vitro and to examine the mechanism through which beta-ME may influence embryo development. A 2 x 2 factorial treatment arrangement was used to evaluate the effect of 0 or 100 microM beta-ME and 0% or 10% FBS on embryos cultured in Medium 199 (M199) in the absence of somatic cells. Embryos were randomly allocated within stage of development (< 8 cells or 8-16 cells) to one of four treatment combinations and were cultured for 6 days. Both beta-ME and FBS promoted increased (p < 0.01) development of embryos to the blastocyst stage, and their effects were greater (p < 0.01) in 8- to 16-cell embryos than in embryos having fewer than 8 cells at the initiation of treatment. The cysteine and cystine content of M199, with and without beta-ME, were determined by HPLC. Medium supplemented with beta-ME contained neither cysteine nor cystine, and it is suggested that these compounds were converted into a mixed disulfide between cysteine and beta-ME. These results indicate that beta-ME is capable of enhancing bovine embryo development in a cell-free, serum-free culture system.

Constitutively active human estrogen receptors containing amino acid substitutions for tyrosine 537 in the receptor protein

To better understand structure-activity relationships in the human estrogen receptor (ER), we examined the role of tyrosine 537 in the transcriptional response of the receptor, since this residue is close to a region of the hormone-binding domain shown previously to be important in hormone-dependent transcriptional activity and because this amino acid has been proposed to be a tyrosine kinase phosphorylation site important in the activity of the ER. We substituted five amino acids at this position (alanine, phenylalanine, glutamic acid, lysine, or serine) and screened these mutants for their biological activities in the presence and absence of estradiol. Two of the ER mutants, Y537A and Y537S, displayed estrogen-independent constitutive activity that was approximately 20% or 100%, respectively, of the activity of the wild type receptor with estradiol, when assessed in two different cell backgrounds using three different estrogen-responsive promoters. In some circumstances, the Y537E and Y537K proteins also exhibited some low level of constitutive activity. The constitutive activity of the mutants, as well as their activity in the presence of E2, was fully suppressed by antiestrogen. The extent of interaction of the constitutively active ERs with the steroid receptor coactivator-1 (SRC-1) closely parallel the magnitude of transcriptional activity of the receptor. Whereas wild type ER showed interaction with SRC-1 only in the presence of estrogen, Y537A and Y537S ER showed moderate or full interaction in the absence of ligand, an interaction that was blocked by antiestrogen, and the magnitude of interaction was increased to or remained at 100% upon estradiol treatment, implying that the ability of an ER to associate with SRC-1 is a good indicator of a transcriptionally active conformational state of the receptor. Our findings indicate that tyrosine 537 is in a region important in the ligand regulation of ER transcriptional activity and that the presence of certain amino acids at this position can shift ER into a conformation that is active even without ligand. However, tyrosine is not required at this site for estrogen binding or transcriptional response to estrogen in the systems investigated. Our findings, interpreted in light of the recently published x-ray crystal structure of the ligand-binding domains of three related receptors of the nuclear receptor superfamily, suggest that some of the amino acid substitutions introduced at position 537 may facilitate the shift of helix 12 of the ER into an active conformation and/or allow for differential stabilization of the receptor in its active form.

Epstein-Barr virus associated Burkitt lymphoma in a heart transplant recipient

This report describes a case of Epstein-Barr [correction of Epstein Barr] Virus related post-transplantation B lymphoproliferative disease of unusual Burkitt lymphoma (BL) type in which combined cytotoxic agents (PACE BOM) successfully produced complete and long-term tumor remission.

Transmission of donor Epstein-Barr virus (EBV) in transplanted organs causes lymphoproliferative disease in EBV-seronegative recipients

Epstein-Barr virus (EBV) is associated with post-transplant lymphoproliferative disease (PTLD). To determine whether the donor EBV isolate is transmitted to the recipient via the allograft and causes PTLD, EBV isolates from four cases of PTLD in cadaveric heart and/or lung transplant recipients were compared with the donor isolates by PCR and DNA sequence analysis. Two recipients who were EBV seronegative at transplantation acquired an EBV isolate indistinguishable from that of the donor and developed PTLD. In contrast, in two patients who were seropositive before transplantation, the donor isolate differed from that present in PTLD of the recipient. The results suggest that the acquisition of donor EBV is a risk factor for PTLD development in a previously seronegative transplant recipient.

Hunter-McAlpine craniosynostosis phenotype associated with skeletal anomalies and interstitial deletion of chromosome 17q

Hunter-McAlpine syndrome is an autosomal dominant disorder consisting of variable manifestations including craniosynostosis, almond-shaped palpebral fissures, small mouth, mild acral-skeletal anomalies, short stature, and mental deficiency. We report on a 9-year-old boy with this phenotype with more severe skeletal abnormalities than previously described. Chromosomes showed del(17)(q23.1-->q24.2); the more severe phenotype may be explained by the deletion. The deletion also suggests the possibility that the gene for Hunter-McAlpine syndrome might map to that region.

Risk assessment of polymyositis/dermatomyositis after treatment with injectable bovine collagen implants

BACKGROUND

Questions have been raised about a possible relation between injectable collagen and polymyositis and dermatomyositis (PM/DM). Predictions of the prevalence of PM/DM have been based on anecdotal estimates of the duration of follow-up for the collagen-treated population.

OBJECTIVE

Our purpose was to study the duration of follow-up for a large sample of collagen-treated patients.

METHODS

Physicians in North America who purchased collagen implants during fiscal year 1988 were categorized according to collagen practice size; one third were randomly invited to participate in the study.

RESULTS

Review of 2622 patient records yielded an average duration of follow-up of 4 years.

CONCLUSION

Five-year incidence rates were used to estimate the expected number of cases of PM/DM in the collagen-treated population. Through June 1993 the expected number was 30.2. The number of confirmed cases after treatment was seven, less than one fourth of the number of cases expected for a model of the collagen-treated population, matched for age, sex, and race.

Protein S-thiolation and dethiolation during the respiratory burst in human monocytes. A reversible post-translational modification with potential for buffering the effects of oxidant stress

Stimulation of the respiratory burst in mouse macrophages or human neutrophils results in the formation of disulfide bonds between low m.w. thiols and sulfhydryl groups on specific cytosolic proteins (S-thiolation). S-thiolation is reversible in certain chemical systems. The aim of the present study was to analyze the dynamic nature of this process in human monocytes under physiologic conditions. We report here that the extent of S-thiolation and the rate of respiratory burst stimulated by opsonized zymosan or phorbol diester increased for 10 to 20 min and then declined (dethiolation) in close association. Individual proteins underwent S-thiolation and dethiolation at different rates. H2O--appeared particularly effective in mediating S-thiolation, based on inhibition of S-thiolation by added catalase and accentuation by azide, which inhibits cellular catalase. S-thiolation did not occur in stimulated monocytes from patients with chronic granulomatous disease. The addition of H2O2 to monocytes or lymphocytes induced rapid S-thiolation (1 to 3 min); a subsequent dethiolation returned most of the proteins to baseline by 15 to 30 min. At 0 degrees C and after addition of 1,3-bis-(2-chloroethyl)-1-nitrosourea, there was effective S-thiolation on exposure to H2O2, but dethiolation was inhibited, suggesting a possible role for glutathione (GSH)/thioredoxin reductase systems in this process. GSH was determined to be the most abundant low m.w. thiol bound to S-thiolated proteins, but gamma-glutamylcysteine and cysteine were also bound. The time of maximal reduction in cytosolic GSH during the respiratory burst (10 min) coincided with the time at which protein-bound GSH was highest. S-thiolation-dethiolation represents a reversible post-translational modification that could protect cellular proteins from irreversible oxidative damage.

Protein S-thiolation and dethiolation during the respiratory burst in human monocytes. A reversible post-translational modification with potential for buffering the effects of oxidant stress

Stimulation of the respiratory burst in mouse macrophages or human neutrophils results in the formation of disulfide bonds between low m.w. thiols and sulfhydryl groups on specific cytosolic proteins (S-thiolation). S-thiolation is reversible in certain chemical systems. The aim of the present study was to analyze the dynamic nature of this process in human monocytes under physiologic conditions. We report here that the extent of S-thiolation and the rate of respiratory burst stimulated by opsonized zymosan or phorbol diester increased for 10 to 20 min and then declined (dethiolation) in close association. Individual proteins underwent S-thiolation and dethiolation at different rates. H2O--appeared particularly effective in mediating S-thiolation, based on inhibition of S-thiolation by added catalase and accentuation by azide, which inhibits cellular catalase. S-thiolation did not occur in stimulated monocytes from patients with chronic granulomatous disease. The addition of H2O2 to monocytes or lymphocytes induced rapid S-thiolation (1 to 3 min); a subsequent dethiolation returned most of the proteins to baseline by 15 to 30 min. At 0 degrees C and after addition of 1,3-bis-(2-chloroethyl)-1-nitrosourea, there was effective S-thiolation on exposure to H2O2, but dethiolation was inhibited, suggesting a possible role for glutathione (GSH)/thioredoxin reductase systems in this process. GSH was determined to be the most abundant low m.w. thiol bound to S-thiolated proteins, but gamma-glutamylcysteine and cysteine were also bound. The time of maximal reduction in cytosolic GSH during the respiratory burst (10 min) coincided with the time at which protein-bound GSH was highest. S-thiolation-dethiolation represents a reversible post-translational modification that could protect cellular proteins from irreversible oxidative damage.

Recent developments and perspectives of biotechnology-derived products

Recent advances in molecular biology especially in the area of rDNA, gene transfer, polymerase chain reaction and hybridoma techniques have provided the necessary molecular tools for the development of a new class of biopharmaceuticals. These biopharmaceuticals include antisense drugs, carbohydrate-based macromolecules and agents that interfere with apoptosis pathways. Cytokines and other immunomodulators also represent an exciting class of new therapeutic entities. The safety evaluation, efficacy, manufacturing and quality control of these complex biopharmaceuticals represent a challenge to the pharmacologist and toxicologist. Finally, the regulatory issues associated with the new biopharmaceuticals need to be addressed to insure the safety of these evolving therapeutic substances.

Drug-nutrient interactions

Nutrition status plays a significant role in a drug's pharmacodynamics. Some disease states and other special conditions affect nutrient status and a drug's therapeutic efficacy. Many classes of drugs, including antimicrobials, hypoglycemics, and hypocholesterolemic agents, can be affected by the presence of food, with the geriatric patient particularly at risk. While a drug's pharmacokinetic profile can usually be predicted, it can be modified by nutrients and by certain pathophysiologic conditions, including aging, hepatic dysfunction, and micronutrients.

Programmable diffractive optical element using a multichannel lanthanum-modified lead zirconate titanate phase modulator

We introduce a programmable diffractive optical element based on an electro-optic phased array implemented with a multichannel lanthanum-modified lead zirconate titanate phase modulator. The design and fabrication procedures are outlined, along with an experimental demonstration of the device. Experimental results from a 16-channel device operating with a 2pi ; voltage of 300 V demonstrate selective beam steering. The programmable diffractive optical element allows for efficient, high-speed high-resolution random-access optical beam steering over a continuous scanning range.

Protein sulfhydryls and their role in the antioxidant function of protein S-thiolation

Protein S-thiolation/dethiolation, i.e., the oxidation of protein sulfhydryls to mixed disulfides and their reduction back to sulfhydryls, is an early cellular response to oxidative stress (1-5). This response may be elicited by oxidative phenomena of diverse origins, and the few cases that have been studied extensively give a limited insight into the metabolic roles and the molecular mechanism of the process. Much of our current understanding arose from experiences with isolated proteins containing "reactive" sulfhydryls (6, 7), but recent experiments at the cellular level have begun to reveal interesting insights that suggest a complexity and importance not appreciated previously (8). This article will discuss the current status of experiments that relate to both the role of the cellular process and to the reactivity of selected proteins that participate in the cellular processes. The discussion will center on the role of glutathione, a molecule of central interest in every aspect of protein S-thiolation and dethiolation.