The CD11b promoter directs high-level expression of reporter genes in macrophages in transgenic mice [published erratum appears in Blood 1995 Apr 1;85(7):1983]

CD11b is the alpha chain of the Mac-1 integrin and is preferentially expressed in myeloid cells (neutrophils, monocytes, and macrophages). We have previously shown that the CD11b promoter directs cell-type- specific expression in myeloid lines using transient transfection assays. To confirm that these promoter sequences contain the proper regulatory elements for correct myeloid expression of CD11b in vivo, we have used the -1.7-kb human CD11b promoter to direct reporter gene expression in transgenic mice. Stable founder lines were generated with two different reporter genes, a Thy 1.1 surface marker and the Escherichia coli lacZ (beta-galactosidase) gene. Analysis of founders generated with each reporter demonstrated that the CD11b promoter was capable of driving high levels of transgene expression in murine macrophages for the lifetime of the animals. Similar to the endogenous gene, transgene expression was preferentially found in mature monocytes, macrophages, and neutrophils and not in myeloid precursors. These experiments indicate that the -1.7 CD11b promoter contains the regulatory elements sufficient for high-level macrophage expression. This promoter should be useful for targeting heterologous gene expression to mature myeloid cells.     

Effect of Octreotide on Human Sphincter of Oddi Motility Following Liver Transplantation

The effect of octreotide on sphincter of Oddimotility was investigated in six liver transplantpatients, employing percutaneous (through the T-tubetract) manometry. Continuous and simultaneous sphincter of Oddi and duodenal motor activities wererecorded before and for 60 min after the administrationof octreotide (100 g subcutaneously) and after theinjection of cholecystokinin (0.02 g/kgintravenously). With octreotide, contraction frequency andbasal pressure significantly increased (P < 0.05).This effect lasted more than 60 min, long afteroctreotide-induced duodenal migrating motor complexphase III activity had ceased. Sphincter of Oddicontraction amplitude and duration were unaffected byoctreotide. Subsequent cholecystokinin administrationtransiently reduced sphincter of Oddi basal pressure and contraction frequency. We conclude thatoctreotide significantly increases sphincter of Oddibasal pressure and contraction frequency. This effect isdistinct from octreotide induction of migrating motor complex phase III activity, persists for aprolonged period, and is inhibited bycholecystokinin.     

Characterization of the p67phox gene: genomic organization and restriction fragment length polymorphism analysis for prenatal diagnosis in chronic granulomatous disease

The genetic defect in the p67phox-deficient form of chronic granulomatous disease (CGD) follows an autosomal recessive pattern of inheritance. When genomic DNA from normal individuals is digested with HindIII and probed with p67phox cDNA an allelic restriction fragment length polymorphism (RFLP) of 4.0 kb or 2.3 kb is detected. We cloned and characterized the p67phox gene using the cDNA and sequenced the exon/intron boundaries, mapping 16 exons on the 40-kb gene. The polymorphic region was then sequenced to identify the inheritance pattern of amniocentesis-derived fetal cells by genomic amplification. The proband, a 9-year-old female patient with p67phox-deficient CGD, and her phenotypically normal mother are homozygous for the RFLP marker, whereas the father and two brothers are heterozygous. The fetus was shown to be heterozygous as well, showing it had inherited at least one normal p67phox gene from the father and that it was predicted to have a normal phenotype. Cord blood samples at birth showed normal oxidative function. Amplification allows rapid detection of the inheritance pattern for fetal diagnosis in informative families. We report the genomic structure of p67phox and an amplification-based method for detection of the marker on chromosome 1q25, used here for prenatal diagnosis of CGD.     

Rationale and design of a prospective study of the clinical significance of atrial arrhythmias detected by implanted device diagnostics: The TRENDS study

Background: Sustained atrial fibrillation (AF) is a common risk factor for stroke. While intermittent AF also appears to pose a substantial stroke risk, the quantitative relationship between the percentage of time spent in AF and stroke risk is poorly specified and “intermittent” AF is not the same as paroxysmal AF. Improved assessment of the impact of AF burden on stroke risk will allow more targeted and safer use of antithrombotic therapy. Methods and Results: The primary objective of this study is to determine if AT/AF (all device detected atrial tachyarrhythmias, including atrial flutter, atrial fibrillation, and atrial tachycardia) burden over a 30 day period is an independent predictor of the occurrence of ischemic stroke, transient ischemic attack (TIA) and/or systemic embolism in subjects not receiving anticoagulation therapy. TRENDS is a prospective, post-market, non-randomized, multicenter study designed to enroll 3100 subjects who have an independent Class I/II indication for cardiac rhythm device implantation and who have demographic features suggestive of an increased risk for thromboembolic complications related to AT/AF. All implanted devices will have the ability to collect long-term AT/AF burden trending data and will be equivalently programmed to ensure consistent data collection. All subjects will be followed with device interrogations every 3 months and clinic visits every 6 months for 1 year. Subjects with a documented history of AT/AF prior to enrollment and those who develop AT/AF during the 12-month follow-up will be followed until the last subject enrolled in the study has completed their 24-month follow-up. Conclusions: The results of the TRENDS study should help clarify the implications of data retrieved from an implantable device with regard to the risk for thromboembolic complications from atrial arrhythmias, even in the absence of symptoms.     

Improved specificity and sensitivity when using pronase-digested lymphocytes to perform flow-cytometric crossmatch prior to renal transplantation

Several laboratories have resorted to flow-cytometric crossmatch (FCXM) in an effort to prevent hyperacute and accelerated renal allograft rejections. The currently employed FCXM has problems with both false-positive and -negative reactions, largely as a result of irrelevant IgG binding to Fc IgG receptors. In 1980, we circumvented this problem by digesting Fc IgG receptors with pronase, and demonstrated that, with immunofluorescence microscopy (IF), detection of IgG anti-HLA antibodies was highly sensitive and specific. In 1995, we introduced the pronase technique to FCXM and showed that this enzyme did not decrease HLA expression. We present herein a prospective study at our institution to determine whether FCXM using pronase-digested (PD) lymphocytes is as sensitive and more specific than FCXM with undigested (UD) lymphocytes when compared with the highly sensitive and specific IF assay. In analyzing the 186 donor-specific pre-renal-transplant crossmatches, we found that PD FCXM was as sensitive and specific as IF and was able to detect weak IgG anti-HLA antibodies that bound to B cells. Fourteen of these patients would have been denied transplants if one were to have relied on UD FCXM. The data clearly indicate that PD FCXM can reliably be used to detect weak IgG anti-HLA antibodies before renal transplantation.     

Diagnosis and Management of Tuberculosis in Transplant Donors: A Donor‐Derived Infections Consensus Conference Report†

Mycobacterium tuberculosis is a ubiquitous organism that infects one‐third of the world's population. In previous decades, access to organ transplantation was restricted to academic medical centers in more developed, low tuberculosis (TB) incidence countries. Globalization, changing immigration patterns, and the expansion of sophisticated medical procedures to medium and high TB incidence countries have made tuberculosis an increasingly important posttransplant infectious disease. Tuberculosis is now one of the most common bacterial causes of solid‐organ transplant donor‐derived infection reported in transplant recipients in the United States. Recognition of latent or undiagnosed active TB in the potential organ donor is critical to prevent emergence of disease in the recipient posttransplant. Donor‐derived tuberculosis after transplantation is associated with significant morbidity and mortality, which can best be prevented through careful screening and targeted treatment. To address this growing challenge and provide recommendations, an expert international working group was assembled including specialists in transplant infectious diseases, transplant surgery, organ procurement and TB epidemiology, diagnostics and management. This working group reviewed the currently available data to formulate consensus recommendations for screening and management of TB in organ donors.     

In vivo behavior of human radioiodinated antithrombin III: distribution among three physiologic pools

It has recently been shown that antithrombin III (AT) distributes between plasma, a noncirculating vascular-associated pool and an extravascular pool in rabbit. Study of the in vivo behavior of autologous human 131I-AT demonstrates that in humans AT also distributes among three pools that are analogous to those found in rabbit. From the in vivo kinetic behavior of the 131I-labeled AT, the fractions of total-body AT in the plasma, noncirculating vascular- associated, and extravascular pools were calculated to be 0.393 +/- 0.015, 0.109 +/- 0.016, and 0.496 +/- 0.014, respectively. From three- exponential plasma radioactivity disappearance curves, an average plasma fractional catabolic rate, j3, of 0.576 +/- 0.034 day-1 was obtained for five healthy young men. This is almost identical to the result obtained if plasma 131I-AT disappearance is assumed to fit a two- exponential curve (0.546 +/- 0.038), where the constant C2 from *Ap(t) = C1e-a1t + C2e-a2t is assumed to be equal to 1 - C1. The fraction of the total vascular AT catabolized daily, j3.5, was calculated to be 0.457 +/- 0.034, and the fractional catabolic rate of total-body AT, jT, averaged 0.2271 +/- 0.0176. The results give further support to a model of in vivo behavior in which the vascular AT distributes between plasma and an endothelial receptor. Thus, the latter may serve to mediate activation of AT for its reaction with coagulation proteases and to mediate its entrance into the endothelial cell, where it is either transported to the extravascular fluids or is catabolized.     

Elderly recipients of hepatitis C positive renal allografts can quickly develop liver disease

Our institution explored using allografts from donors with Hepatitis C virus (HCV) for elderly renal transplantation (RT). Thirteen HCV- elderly recipients were transplanted with HCV+ allografts (eD+/R-) between January 2003 and April 2009. Ninety HCV- elderly recipients of HCV- allografts (eD-/R-), eight HCV+ recipients of HCV+ allografts (D+/R+) and thirteen HCV+ recipients of HCV- allografts (D-/R+) were also transplanted. Median follow-up was 1.5 (range 0.8-5) years. Seven eD+/R- developed a positive HCV viral load and six had elevated liver transaminases with evidence of hepatitis on biopsy. Overall, eD+/R- survival was 46% while the eD-/R- survival was 85% (P = 0.003). Seven eD+/R- died during follow-up. Causes included multi-organ failure and sepsis (n = 4), cancer (n = 1), failure-to-thrive (n = 1) and surgical complications (n = 1). One eD+/R- died from causes directly related to HCV infection. In conclusion, multiple eD+/R- quickly developed HCV-related liver disease and infections were a frequent cause of morbidity and mortality.