Novel insights into bicuspid aortic valve (BAV) aortopathy: Long non-coding RNAs TUG1 and MIAT are differentially expressed in BAV ascending aortas

BACKGROUND

Whilst a combination of genetically mediated vulnerability and haemodynamic insult is suspected to contribute to bicuspid aortic valve (BAV) aortopathy, the underlying pathophysiological mechanisms are poorly understood.

METHODS

Utilising RT-qPCR, we compared the expression of 28 potentially relevant long non-coding RNA (lncRNA) in aortic tissue from BAV patients undergoing aortic surgery for aortopathy, to healthy controls. Relative lncRNA expression was measured using ΔΔCT, with fold-change calculated as RQ=2^-ΔΔCT.

RESULTS

When comparing samples from BAV patients (n=29, males n=25; median age 58 years, Q1-Q3 51-65, maximum aortic dimension 50±5mm) with healthy controls (n=7; males n=4, p=0.12; median age 39 years, Q1-Q3 18-47, p=0.001), there were two differentially expressed lncRNA: TUG1 expression was significantly lower in BAV aortic tissue (RQ 0.59, 95% CI 0.50-0.69, p=0.02), whilst MIAT expression was significantly higher (RQ 2.87, 95% CI 1.96-4.20, p=0.01). Sensitivity analysis including only patients with normal BAV function showed similar trends of differential expression of TUG1 (RQ 0.69, 95% CI 0.50-0.90, p=0.29) and MIAT (RQ 2.55, 95% CI 1.21-5.36, p=0.29) compared to controls.

CONCLUSIONS

LncRNA TUG1 and MIAT are differentially expressed in BAV aortopathy compared to healthy controls, independent of BAV haemodynamics. Aberrant lncRNA expression may be involved in the pathogenesis of BAV aortopathy.

Racial and gender pay disparities: The role of education

We investigate whether white women, black women, and black men earn less than white men because of 1) lower educational attainment and/or 2) lower wage returns to the same levels and academic fields of attainment. Using the 1979-2012 waves of the American National Longitudinal Survey of Youth (NLSY79), we examine how educational attainment and academic fields of study impact pay. Regression decompositions show that differences in attainment and in academic fields explain 13 to 23 percent of the racial pay gaps, but none of the gender pay gaps. Random effects models test for race and gender differences in the wage returns to education. Men of both races receive higher wage returns relative to women, while black women receive lower returns relative to all groups for master's degrees. Our intersectional approach reveals that equalizing educational attainment would reduce racial pay gaps, whereas equalizing wage returns to education would reduce gender pay disparities. Moreover, black women's earnings are multiply disadvantaged, both by their lower attainment relative to white women, and their lower returns to education relative to all groups studied.

1162 Financial Savings and Improved Outcomes from an Innovative, Integrated Sleep Apnea Management Program for a Safety Net Population: 5-Year Results

Introduction

Sleep disorders are extremely common in the general population and are associated with an increased risk for fatal accidents, heart disease, stroke, neurocognitive decline, and diabetes. Sleep problems disproportionately affect socioeconomically disadvantaged and under resourced communities. We present here a 5-year analysis of a private-public partnership between a private sleep medicine practice (Redwood Pulmonary Medical Associates, RPMA) and county medical system (the Health Plan of San Mateo) to provide a coordinated, value-based sleep apnea program to adult residents of San Mateo County, CA.

Methods

Referring providers send referrals to a single location (RPMA), and sleep consultations, testing, follow-up care, and CPAP management occur out of the same location by a dedicated staff. Limited channel cardiopulmonary (CP) sleep testing initiated in the office and completed at home was done for most patients. Patients with AHI>5 plus daytime sleepiness were offered nasal CPAP, unlimited mask fittings, and compliance checks.

Results

2101 CP tests were successfully completed (93.5%). There were 49.6% females and 50.4% males, with an average age of 51.6 years. 31% had severe obstructive sleep apnea (OSA) and 59% were moderate or severe. 1471 (65%) of patients were given prescriptions for CPAP and 471 (32%) were still using CPAP at 5 years, 68.7% of whom were initiated within 3 years of the analysis. Of the patients returning satisfaction surveys, 97% would recommend the program to a relative or friend, and all respondents (99 to date) who were using CPAP felt it had benefitted their health overall. Comparing actual costs of the program to projected fee-for-service costs for the same services, the program saved the Health Plan of San Mateo $1,132,510, or 51.4%.

Conclusion

This program demonstrates the potential clinical and financial benefit of private-public partnerships in administering clinical programs to high risk populations, as private businesses can quickly adapt to new technologies, financial metrics, and standards of care.

Support

No outside financial support was provided

Targeted Delivery of Iron Oxide Nanoparticle-Loaded Human Embryonic Stem Cell-Derived Spherical Neural Masses for Treating Intracerebral Hemorrhage

This study evaluated the potential of iron oxide nanoparticle-loaded human embryonic stem cell (ESC)-derived spherical neural masses (SNMs) to improve the transportation of stem cells to the brain, ameliorate brain damage from intracerebral hemorrhage (ICH), and recover the functional status after ICH under an external magnetic field of a magnet attached to a helmet. At 24 h after induction of ICH, rats were randomly separated into three experimental groups: ICH with injection of phosphate-buffered saline (PBS group), ICH with intravenous injection of magnetosome-like ferrimagnetic iron oxide nanocubes (FION)-labeled SNMs (SNMs* group), and ICH with intravenous injection of FION-labeled SNMs followed by three days of external magnetic field exposure for targeted delivery by a magnet-embedded helmet (SNMs*+Helmet group). On day 3 after ICH induction, an increased Prussian blue-stained area and decreased swelling volume were observed in the SNMs*+Helmet group compared with that of the other groups. A significantly decreased recruitment of macrophages and neutrophils and a downregulation of pro-inflammatory cytokines followed by improved neurological function three days after ICH were observed in the SNMs*+Helmet group. Hemispheric atrophy at six weeks after ICH was significantly decreased in the SNMs*+Helmet group compared with that of the PBS group. In conclusion, we have developed a targeted delivery system using FION tagged to stem cells and a magnet-embedded helmet. The targeted delivery of SNMs might have the potential for developing novel therapeutic strategies for ICH.

Rapidly Progressive Small Bowel Necrosis in a Previously Healthy Child without Proven Mechanical Obstruction

Bowel ischemia is a life-threatening surgical emergency. We report a case of rapidly progressive bowel necrosis in a previously healthy child without proven mechanical small bowel obstruction. The definite diagnosis was established at the time of an exploratory operation. Of note, imaging studies and even a laparotomy did not reveal any evidence of acute appendicitis or mechanical obstruction such as intussusception or Meckel's diverticulum. During hospitalization, since we could not rule out surgical abdomen after inconclusive image findings, we closely followed the patient and repeated physical examinations carefully. Eventually surgical exploration was performed based on changes in clinical condition, which proved to be the right decision for the patient. We propose that in children with suspected strangulation of small bowel obstruction, especially when imaging findings do not provide a conclusive diagnosis, the timely exploratory surgical approach ought to be chosen based on carefully observed clinical findings and other evaluations.

Human papillomavirus (HPV) and somatic EGFR mutations are essential, mutually exclusive oncogenic mechanisms for inverted sinonasal papillomas and associated sinonasal squamous cell carcinomas

Background

Inverted sinonasal (Schneiderian) papilloma (ISP) is a locally aggressive neoplasm often associated with sinonasal squamous cell carcinoma (SNSCC). While the etiology of ISP is not well understood, human papillomavirus (HPV) has been detected in a subset of cases. Our group recently identified activating somatic EGFR mutations in the majority of ISP and ISP-associated SNSCC. However, the relationship between EGFR mutations and HPV infection has not been explored.

Patients and methods

We evaluated 58 ISP and 22 ISP-associated SNSCC (including 13 patients with matched ISP/SNSCC samples), as well as 14 SNSCC without clinical or pathologic evidence of an associated ISP. Formalin-fixed, paraffin-embedded samples were evaluated for EGFR mutations using Sanger sequencing and for HPV infection using GP5+/GP6+ PCR. HPV subtyping based on the L1 sequence was done for HPV positive cases including temporally distinct tumors for four patients. Clinicopathologic data including progression free survival was also analyzed.

Results

All ISP and ISP-associated SNSCC demonstrated either an EGFR mutation or HPV infection. HPV and EGFR mutation were mutually exclusive in all cases of ISP-associated SNSCC and all but one ISP; this case was only weakly HPV positive, and analysis of a prior temporally distinct ISP specimen from this patient failed to show HPV infection, suggesting transient infection/incidental colonization. HPV subtypes in ISP and ISP-associated SNSCC were predominantly low-risk, in contrast with SNSCC without ISP association, which showed frequent high-risk HPV. All paired ISP and associated SNSCC samples demonstrated concordant HPV status and EGFR genotypes. ISP progression to SNSCC was significantly associated with the presence of HPV infection and the absence of an EGFR mutation (log-rank = 9.620, P = 0.002).

Conclusions

Collectively our data show that EGFR mutations and HPV infection represent essential, alternative oncogenic mechanisms in ISP and ISP-associated SNSCC.

The utility of the radionuclide probe in parathyroidectomy for primary hyperparathyroidism

INTRODUCTION Parathyroidectomy is the definitive treatment for primary hyperparathyroidism but the intraoperative identification of adenomas is challenging. The aim of this study was to evaluate the utility of a radionuclide probe (RNP) in addition to intraoperative parathyroid hormone ( IOPTH) measurement as an intraoperative diagnostic adjunct in patients undergoing parathyroidectomy for primary hyperparathyroidism. METHODS This was a retrospective cohort study of patients treated between 2004 and 2015 in a university affiliated teaching hospital. Patients were grouped into those with RNP use (RNP+) and those without (RNP-). The primary outcome measure was rate of operative failure, which included false positives. The diagnostic sensitivity and positive predictive value of both RNP and IOPTH were also evaluated. RESULTS A total of 298 patients were included in the study, 127 (42.6%) being in the RNP+ group and 171 (57.4%) in the RNP- group. The false positive rate for the RNP+ patients was 1.6% compared with 9.4% for RNP- patients (p=0.006, hazard ratio [HR]: 6.45). The rates of operative failure were 6.3% and 11.7% respectively (p=0.159, HR: 1.97). RNP use had a sensitivity of 92.0% and a positive predictive value of 98.3% compared with 78.6% and 95.2% respectively for IOPTH monitoring. CONCLUSIONS RNP use is associated with fewer false positives and reduced operative failure than IOPTH measurement. It also has a higher sensitivity and positive predictive value. RNP use is recommended in centres that have the required facilities.

Effects of Melatonin on Colchicine-Treated PLBs of Dendrobium sonia-28 Orchid

Dendrobium hybrid orchid is popular in orchid commercial industry due to its short life cycle and ability to produce various types of flower colours. This study was conducted to identify the morphological, biochemical and scanning electron microscopy (SEM) analysis in the Dendrobium sonia-28 orchid plants. In this study, 0.05 and 0.075 % of colchicine-treated Dendrobium sonia-28 (4-week-old culture) protocorm-like bodies (PLBs) were treated in different concentrations of melatonin (MEL) posttreatments (0, 0.05, 0.1, 0.5, 1, 5 and 10 μM). Morphological parameters such as number of shoots, growth index and number of PLBs were determined. In the 0.05 and 0.075 % of colchicine-treated PLBs which were posttreated with 0.05 μM MEL resulted in the highest value of the morphological parameters tested based on the number of shoots (84.5 and 96.67), growth index (16.94 and 12.15) and number of PLBs (126.5 and 162.33), respectively. SEM analysis of the 0.05 μM MEL posttreatment on both the colchicine-treated regenerated PLBs showed irregular cell lineages, and some damages occurred on the stomata. This condition might be due to the effect of plasmolyzing occurred in the cell causing irregular cell lineages.

Population pharmacokinetic and pharmacodynamic modeling of transformed binary effect data of triflusal in healthy Korean male volunteers: a randomized, open-label, multiple dose, crossover study

Background

Triflusal is a drug that inhibits platelet aggregation. In this study we investigated the dose-exposure-response relationship of a triflusal formulation by population pharmacokinetic (PK) and pharmacodynamic (PD) modeling of its main active metabolite, hydroxy-4-(trifluoromethyl) benzoic acid (HTB).

Methods

This study was a randomized, open-label, multiple-dose, two-period, two-treatment, comparative crossover design. All volunteers received a single oral loading dose of 900 mg of triflusal on Day 1, followed by a dose of 600 mg/day from Day 2 to 9. Using data from 34 healthy volunteers, 476 HTB plasma concentration data points and 340 platelet aggregation data points were used to construct PK and PD models respectively using NONMEM (version 6.2). As the PD endpoint was qualitative, we implemented binary analysis of ‘inhibition’ and ‘non-inhibition’ rather than using the actual value of the test. The final PK-PD model was evaluated using a visual predictive check (VPC) and bootstrap.

Results

The time-concentration profile of HTB over the entire dosing period was described by a one-compartment model with a first-order formation rate constant for HTB. Weight was selected as a covariate for clearance and volume of triflusal, respectively. The structure and the population estimates for triflusal PK were as follows: oral clearance (CL/F) = 0.2 · (weight/71.65)^0.845 L/h, oral volume of distribution (V/F) = 8.3 · (weight/71.65) L, and k_f = 0.341 h^-1. A sigmoid relationship between triflusal concentration and the probability of significant inhibition with shape factor was chosen as the final PD model. No time delay between concentration and response was identified. The final structure between predicted concentration and the probability of inhibition of platelet aggregation (IPA) relationship was as follows: Probability of . Thus, we concluded this relationship is more like quantal concentration-response relationship. The current dosing regimen was considered to be efficacious based on the EC₅₀ estimate of 84.9 μg/mL obtained in this study.

Conclusions

A PK and binary probability PD model of triflusal was successfully developed for Korean healthy volunteers. The model may be used to further prediction inhibition of platelet aggregation by triflusal.

Trial registration

Clinical Research Information Service (CRIS), KCT0001299 (Registered December 5, 2014)

Rapid genotyping of Plasmodium vivax Pvs25 and Pv38 genes by using mismatch specific endonuclease

Mismatch specific endonuclease (MSE) method was used to detect natural polymorphisms in Pvs25 and Pv38 genes of Plasmodium vivax. Eighty seven patients with P. vivax were recruited in the Republic of Korea (ROK). Pvs25 and Pv38 genes were amplified by polymerase chain reaction (PCR), and the PCR amplicons were mixed with reference DNA sequences. Following the denaturation and gradual annealing, the product mixtures were cleaved by the MSE. Heteroduplex types were readily detected by gel electrophoresis, where extra bands with shorter sizes would appear from the cleavage. After MSE cleavage of 657- bp product from Pvs25 mixtures, three genotypes were detected, while Pv38 mixtures with 1220-bp products presented two genotypes in ROK isolates. After the MSE cleavage, the mismatched samples of Pvs25 and Pv38 were completely sequenced, and the results were in complete agreement with the MSE analyses. In conclusion, genotyping of Pvs25 and Pv38 with MSE cleavage could be a potential method for the high-throughput screening of the large field samples.

Quantile normalization approach for liquid chromatography-mass spectrometry-based metabolomic data from healthy human volunteers

In metabolomic research, it is important to reduce systematic error in experimental conditions. To ensure that metabolomic data from different studies are comparable, it is necessary to remove unwanted systematic factors by data normalization. Several normalization methods are used for metabolomic data, but the best method has not yet been identified. In this study, to reduce variation from non-biological systematic errors, we applied 1-norm, 2-norm, and quantile normalization methods to liquid chromatography-mass spectrometry (LC-MS)-based metabolomic data from human urine samples after oral administration of cyclosporine (high- and low-dose) in healthy volunteers and compared the effectiveness of the three methods. The principal component analysis (PCA) score plot showed more obvious groupings according to the cyclosporine dose after quantile normalization than after the other two methods and prior to normalization. Quantile normalization is a simple and effective method to reduce non-biological systematic variation from human LC-MS-based metabolomic data, revealing the biological variance.

Pattern recognition analysis for hepatotoxicity induced by acetaminophen using plasma and urinary 1H NMR-based metabolomics in humans

Drug-induced liver injury (DILI) is currently an increasingly relevant health issue. However, available biomarkers do not reliably detect or quantify DILI risk. Therefore, the purpose of this study was to comparatively evaluate plasma and urinary biomarkers obtained from humans treated with acetaminophen (APAP) using a metabolomics approach and a proton nuclear magnetic resonance (NMR) platform. APAP (3 g/day, two 500 mg tablets every 8 h) was administered to 20 healthy Korean males (age, 20-29 years) for 7 days. Urine was collected daily before and during dosing and 6 days after the final dose. NMR spectra of these urine samples were analyzed using principal component analysis (PCA) and partial least-squares-discrimination analysis. Although the activities of aspartate aminotransferase and lactate dehydrogenase were significantly increased 7 days post-APAP treatment, serum biochemical parameters of aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, total bilirubin, γ-glutamyl transpeptidase, and lactate dehydrogenase were within normal range of hepatic function. However, urine and plasma (1)H NMR spectroscopy revealed different clustering between predosing and after APAP treatment for global metabolomic profiling through PCA. Urinary endogenous metabolites of trimethylamine-N-oxide, citrate, 3-chlorotyrosine, phenylalanine, glycine, hippurate, and glutarate as well as plasma endogenous metabolites such as lactate, glucose, 3-hydroxyisovalerate, isoleucine, acetylglycine, acetone, acetate, glutamine, ethanol, and isobutyrate responded significantly to APAP dosing in humans. Urinary and plasma endogenous metabolites were more sensitive than serum biochemical parameters. These results might be applied to predict or screen potential hepatotoxicity caused by other drugs using urinary and plasma (1)H NMR analyses.

Pharmacometabolomic approach to predict QT prolongation in guinea pigs

Drug-induced torsades de pointes (TdP), a life-threatening arrhythmia associated with prolongation of the QT interval, has been a significant reason for withdrawal of several medicines from the market. Prolongation of the QT interval is considered as the best biomarker for predicting the torsadogenic risk of a new chemical entity. Because of the difficulty assessing the risk for TdP during drug development, we evaluated the metabolic phenotype for predicting QT prolongation induced by sparfloxacin, and elucidated the metabolic pathway related to the QT prolongation. We performed electrocardiography analysis and liquid chromatography-mass spectroscopy-based metabolic profiling of plasma samples obtained from 15 guinea pigs after administration of sparfloxacin at doses of 33.3, 100, and 300 mg/kg. Principal component analysis and partial least squares modelling were conducted to select the metabolites that substantially contributed to the prediction of QT prolongation. QTc increased significantly with increasing dose (r = 0.93). From the PLS analysis, the key metabolites that showed the highest variable importance in the projection values (>1.5) were selected, identified, and used to determine the metabolic network. In particular, cytidine-5'-diphosphate (CDP), deoxycorticosterone, L-aspartic acid and stearic acid were found to be final metabolomic phenotypes for the prediction of QT prolongation. Metabolomic phenotypes for predicting drug-induced QT prolongation of sparfloxacin were developed and can be applied to cardiac toxicity screening of other drugs. In addition, this integrative pharmacometabolomic approach would serve as a good tool for predicting pharmacodynamic or toxicological effects caused by changes in dose.

Clinical evaluation of efficacy and tolerability of HMC05 in healthy subjects with normal and high-normal blood pressure: a pilot study

HMC05, a formulation containing eight different herbal extracts, has been used widely for several thousand years in China, Japan, and Korea as a remedy for hypertension and headache. Although its anti-inflammatory effects in mouse monocytic cell lines and anti-atherosclerotic effects in apoE-knockout mice have been reported, the pharmacodynamic effects of HMC05 in human subjects have not yet been investigated. We evaluated the efficacy and tolerability of this drug in 14 healthy male Korean subjects with normal or high-normal blood pressure (BP) in a randomized, single-blind, crossover study with a 2-week washout period. Four 500-mg tablets of HMC05 or placebo were orally administered three times daily to nine subjects with normal BP and five subjects with high-normal BP for 4 weeks. To assess the pharmacodynamic effects of HMC05, levels of high-sensitivity C-reactive protein and homocysteine, BP, and flow-mediated vasodilation were measured before and after the 4-week medication period with evaluation of tolerability. All 14 subjects completed the study, and HMC05 was well tolerated with no significant adverse events. HMC05 did not exhibit a significant BP-lowering effect in either BP group, and there were no significant differences in other pharmacodynamic values after HMC05 or placebo administration in the two groups. Further study is needed to evaluate the efficacy and tolerability of HMC05 in an adequate number of patients with hypertension.

Hepatocyte-like cells from human mesenchymal stem cells engrafted in regenerating rat liver tracked with in vivo magnetic resonance imaging

Cell transplantation using hepatocytes derived from stem cells has been regarded as a possible alternative treatment for various hepatic disorders. Recently, mesenchymal stem cells (MSCs) from the bone marrow have shown the potential to differentiate into hepatocytes in in vitro and in vivo conditions. Noninvasive imaging techniques allowing in vivo assessment of the location of cells are of great value for experimental studies in which these cells are transplanted. We labeled human mesenchymal stem cells (hMSCs) with green fluorescence protein (GFP) and superparamagnetic iron oxide (SPIO) using a transfection agent (GenePORTER). Cellular labeling was evaluated with magnetic resonance (MR) imaging of labeled suspensions, and Prussian blue staining for iron assessment. hMSCs labeled with SPIO and GFP were injected into the portal veins of immunosuppressed, hepatic-damaged rats. MR imaging findings were compared histologically. To identify the differentiation of hMSCs into hepatocytes and to trace the hepatocytes with molecular imaging, we observed the potential of SPIO and GFP double-labeled hMSCs to differentiate into hepatocyte-like cells in the regenerating rat liver. Serial MR imaging showed the possible detection of transplanted cells in the early period of transplantation. Our results indicate that magnetic labeling of hMSCs with SPIO may enable cellular MR imaging and tracking in experimental in vivo settings.

Detection of the c-kit D816V mutation in systemic mastocytosis by allele-specific PCR

AIMS

The c-kit D816V activating mutation is found in >80% of cases of systemic mastocytosis (SM) and represents a potential drug target. Furthermore, because D816V is one of the diagnostic criteria for SM, it is clinically relevant to determine whether the mutation is present. Traditional techniques such as DNA sequencing are often not sensitive enough to detect mutations in low-abundance tumour cells, including SM. Here, an allele-specific assay to detect the D816V mutation in DNA from archived formalin-fixed paraffin-embedded tissues is described.

METHODS

A two-tube PCR format was employed to amplify c-kit exon 17 as a control and an allele-specific reaction to selectively amplify the D816V mutant allele using standard oligonucleotides. A D816V-mutant plasmid control was generated by site-directed mutagenesis of wild-type cells. 14 cases of SM, one D816V-positive seminoma sample, and 35 cases without SM were analysed using the assay.

RESULTS

The assay successfully amplified D816V in the mutant plasmid control, 13/14 cases of SM, and confirmed D816V in a seminoma sample. In addition, D816V was not amplified in 35/35 cases without SM. Serial dilution experiments demonstrated sensitivity down to <1%.

CONCLUSION

A sensitive, specific and cost-effective assay to detect the D816V mutation in archived formalin-fixed paraffin-embedded tissues from cases of SM has been developed.

Loss of Ubr1 promotes aneuploidy and accelerates B-cell lymphomagenesis in TLX1/HOX11-transgenic mice

The TLX1/HOX11 homeobox gene was originally identified at the recurrent t(10;14)(q24;q11) translocation breakpoint, a chromosomal abnormality observed in 5-7% of T-cell acute lymphoblastic leukemias (T-ALLs). Proviral insertional mutagenesis studies performed on transgenic mice ectopically expressing TLX1/HOX11 in B lymphocytes (IgHmu-HOX11(Tg) mice) revealed the Ubr1 gene locus as a frequent site of proviral insertion, concomitant with accelerated development of diffuse large B-cell lymphoma. Insertion into this genomic region was confirmed by Southern blotting and by the ability to generate a polymerase chain reaction (PCR) amplicon across the viral-genome junction. Western immunoblot and semiquantitative reverse transcriptase-PCR analysis revealed downregulated expression of the Ubr1 gene product subsequent to viral integration. Loss or reduced levels of Ubr1 expression was associated with 5/14 spontaneous B-cell lymphomas in IgHmu-HOX11(Tg) mice and one of nine primary human T-ALLs. To gain mechanistic insight into the cooperativity between TLX1/HOX11 and Ubr1, IgHmu-HOX11(Tg)/Ubr1(-/-) mice were generated. IgHmu-HOX11(Tg)/Ubr1(-/-) mice exhibited a modest but statistically significant acceleration of disease onset relative to IgHmu-HOX11(Tg)/Ubr1(+/-) mice. Moreover, micronucleus assays to detect for chromosome missegregation were conducted and revealed increased presence of micronuclei in IgHmu-HOX11(Tg)/Ubr1(-/-) primary B lymphocyte cultures, and in both TLX1/HOX11-overexpressing T cell lines and fibroblast cultures following transfection with short interfering RNAs (siRNAs) targeting Ubr1. Karyotyping of primary B lymphocyte cultures revealed increased incidences of hypodiploid karyotypes. Finally, mitotic figures analysed from Ubr1 siRNA-transfected fibroblast cultures revealed no defects in chromosome congression to the metaphase plate, but increased incidences of atypical anaphase figures, including the development of anaphase bridges and lagging chromosomes. Based on these findings, we identify a synergistic role between TLX1/HOX11 overexpression and Ubr1 inactivation in promoting chromosome missegregation, permitting the accrual of additional chromosome losses and cytogenic abnormalities en route to malignancy.

Dysregulated expression of mitotic regulators is associated with B-cell lymphomagenesis in HOX11-transgenic mice

Dysregulated expression of the homeobox gene, HOX11 is a frequent etiologic event in T-cell acute lymphoblastic leukemias. HOX11-transgenic mice (IgHmu-HOX11Tg)-expressing HOX11 in the B-cell compartment develop B-cell lymphomas with extended latency. The latency suggests that additional genetic events are required prior to the onset of malignant lymphoma. We report the identification of 17 HOX11 collaborating genes, revealed through their propensity to be targeted in a proviral insertional mutagenesis screen. Seven integrations disrupted genes in mitotic spindle checkpoint control, suggesting that cells with elevated HOX11 expression are especially sensitive to dysregulation of chromosome segregation during mitosis. IgHmu-HOX11Tg primary B-lymphocyte cultures exposed to the aneugenic agents, colchicine and colcemid, exhibited increased incidences of chromosome missegregation as assessed by cytokinesis-block micronucleus assays. Additionally, IgHmu-HOX11Tg cultures were shown to exhibit aberrant bypass of spindle checkpoint arrest, as assessed by the increased presence of cycling cells determined by assessment of DNA content and by BrdU immunolabelling. Western immunoblotting revealed elevated expression of the mitotic effector molecules, cyclin A, cyclin B1 and cdc20 in IgHmu-HOX11Tg cultures. Moreover, spontaneously arising lymphoid neoplasms in IgHmu-HOX11Tg mice frequently exhibit aberrant expression of mitotic regulators, concomitant with increased development of micronuclei, abnormal mitotic checkpoint control and increased incidences of abnormal karyotypes when expanded in culture. Collectively, these findings indicate that abnormal regulation of spindle checkpoint control as a result of HOX11 overexpression leads to a heightened predisposition for development of aneuploidy, contributing to oncogenesis.

Validation of cDNA microarray gene expression data obtained from linearly amplified RNA

BACKGROUND

DNA microarray technology has permitted the analysis of global gene expression profiles for several diseases, including cancer. However, standard hybridisation and detection protocols require micrograms of mRNA for microarray analysis, limiting broader application of this technology to small excisional biopsies, needle biopsies, and/or microdissected tissue samples. Therefore, linear amplification protocols to increase the amount of RNA have been developed. The correlation between the results of microarray experiments derived from non-amplified RNA and amplified samples needs to be evaluated in detail.

METHODS

Total RNA was amplified and replicate hybridisation experiments were performed with linearly amplified (aRNA) and non-amplified mRNA from tonsillar B cells and the SUDHL-6 cell line using cDNA microarrays containing approximately 4500 genes. The results of microarray differential expression using either source of RNA (mRNA or aRNA) were also compared with those found using real time quantitative reverse transcription polymerase chain reaction (QRT-PCR).

RESULTS

Microarray experiments using aRNA generated reproducible data displaying only small differences to data obtained from non-amplified mRNA. The quality of the starting total RNA template and the concentration of the promoter primer used to synthesise cDNA were crucial components of the linear amplification reaction. Approximately 80% of selected upregulated and downregulated genes identified by microarray analysis using linearly amplified RNA were confirmed by QRT-PCR using non-amplified mRNA as the starting template.

CONCLUSIONS

Linear RNA amplification methods can be used to generate high fidelity microarray expression data of comparable quality to data generated by microarray methods that use non-amplified mRNA samples.

An immunophenotypic and molecular study of primary large B-cell lymphoma of bone

Primary non-Hodgkin's lymphomas of bone (PNHLB) is a rare form of extranodal lymphoma. Many studies have reported the clinical, radiologic, and histopathologic characteristics of PNHLB; however, their molecular features have not been well studied. In this report, we present the immunophenotypic and molecular characteristics of 20 primary large B-cell lymphoma (PLBCL) of bone from 20 adults. Most demonstrated centroblastic morphology, with the majority exhibiting nuclear multilobation. One case (5%) demonstrated anaplastic features with strong CD30 expression but was ALK-1 negative. BCL-6 expression was seen in 6 of 20 cases, and strong p53 protein expression was seen in 11 of 20 (55%) cases. The majority of cases analyzed (13/18 = 72%) demonstrated a clonal B-cell process by IgH gene rearrangement studies. Of the five cases that did not demonstrate a clonal population, two expressed BCL-6 protein. No cases demonstrated a bcl-2/JH rearrangement, but BCL-2 protein expression was seen in 11 of 20 (55%) cases. In summary, primary lymphoma of bone is largely a non-Hodgkin's lymphoma of large B-cell type. Our studies demonstrate that p53 and BCL-2 expression may play a role in the pathogenesis of PLCBL of bone. In addition, a subset of the cases are of putative germinal center B-cell origin based on the expression of BCL-6 protein and may be genetically distinct from follicle center lymphomas. The results provide evidence for molecular heterogeneity within primary large B-cell lymphomas of bone.

ALVAC-mediated gene transfer is efficient in lymphoid malignancies of T-and early B-cell origin, but not in tumors arising from mature B-cells

Natural attenuation of ALVAC virus in mammals makes it an attractive vector for cancer vaccine therapy of immunocompromised hosts, such as patients with lymphoid malignancies. However, the transduction efficiency of ALVAC constructs in lymphoid tumors has not yet been characterized. We studied a wide spectrum of human T- and B-cell leukemia and lymphomas and found significant heterogeneity of the ALVAC-mediated gene product expression in these tumors. While ALVAC-B7.1, ALVAC-B7.2, or ALVAC-luciferase vectors effectively expressed recombinant genes in malignancies arising from T- or early B-cell precursors, negative or low expression of ALVAC recombinant genes occurred in tumors arising from mature B-cells. We showed that ALVAC-encoded B7.1 or B7.2 was continuously expressed on the infected, and subsequently irradiated, leukemia cells, and only cells with ALVAC-mediated expression of costimulatory molecules (but not unmodified leukemia cells or those infected with the ALVAC-parental vector) induced significant proliferation and IFN-gamma production by alloreactive T-cells. These data provide the rationale for clinical studies using the ALVAC vector system for gene transfer into lymphoid tumors of T- and early B-cell origin to render them more immunogenic, while alternative strategies should be considered for immunotherapy of mature B-cell malignancies.

Down-regulation of telomerase activity in malignant lymphomas by radiation and chemotherapeutic agents

The effects of radiation and cytotoxic agents on telomerase activity in lymphoma cells were analyzed by a polymerase chain reaction-based telomeric repeat amplification protocol coupled with an enzyme-linked immunosorbent assay, reverse transcriptase-polymerase chain reaction for the expression of the catalytic subunit of telomerase (hTERT), and by Western blot analysis in three lymphoma cell lines (Jurkat, Raji, CEM-6). Telomeric repeat amplification protocol-enzyme-linked immunosorbent assay demonstrated high basal levels of telomerase activity in all cell lines compared to normal and activated peripheral blood lymphocytes. A significant decrease in telomerase activity was observed in all cell lines after exposure to vincristine for 24 hours. The decrease in telomerase activity paralleled the decrease in cell viability in Jurkat and CEM-6 cells but not in Raji cells. Radiation exposure inhibited the telomerase activity of Jurkat and CEM-6 cells whereas Raji cells were unaffected. Cell cycle analysis demonstrated a significant G(2)/M arrest by cisplatin, VP-16, and vincristine. In contrast to the decline in telomerase activity, the level of hTERT RNA and protein increased. Furthermore, the induction of hTERT was preceded by increased expression of the cyclin-dependent kinase inhibitor, p27/Kip1 protein, and p53. These results indicate that telomerase activity is down-regulated by anti-neoplastic agents in lymphoma cells, however expression of hTERT may not be correlated with telomerase activity. We also show that p27/Kip1 may be involved in the G(2)/M growth arrest induced by anti-neoplastic agents.

Heterogeneity of functional GABA(A) receptors in rat dentate gyrus neurons revealed by a change in response to drugs during the whole-cell current time-course

We examined if the drug sensitivity of GABA(A) receptors in dentate gyrus granule neurons changed during the whole-cell current time-course. Effects of drugs on currents evoked immediately (the peak current) upon drug application and currents remaining about two seconds later (semi-plateau current) were compared. The apparent affinity for GABA (EC(50)) of the peak and the semi-plateau current were 14 and 4 microM, respectively. Bicuculline inhibited 50% of the peak and the semi-plateau current (IC(50)) at 7 and 36 microM, respectively, while 100 microM was required for full inhibition of the 100 microM GABA-evoked current. Zinc inhibited about 50% of the peak current with an IC(50) value of 94 microM whereas biphasic, but complete inhibition of the semi-plateau current was recorded with IC(50) values of 3 and 558 microM. The decay phase of the 100 microM GABA-evoked current was fitted by a fast (tau(1), 100-300 ms) and a slow (tau(2), 1-2 s) time-constants in all cells. The relative current amplitude associated with the fast (A1) and the slow (A2) component varied. The A1 current amplitude appeared more sensitive to bicuculline than the A2 current while the opposite was true for zinc. The results are consistent with heterogenous population of functional GABA(A) receptors in the dentate gyrus granule neurons.

Frequent cyclin D1 gene amplification and protein overexpression in oral epithelial dysplasias

Amplification of the cyclin D1 gene has been identified in 17-55% of head and neck squamous cell carcinoma. In some tumors, this alteration has been associated with decreased survival and increased recurrence rates. In precancerous lesions of the mouth, the frequency of cyclin D1 gene amplification is not known. In addition, it is unknown whether amplification of the gene translates to overexpressed cyclin D1 protein in these lesions. We examined 59 formalin-fixed, paraffin embedded tissue biopsies of oral epithelial dysplasias (OED) and 25 oral squamous cell carcinoma (SCC) from the floor of the mouth for cyclin D1 gene and protein levels. Genomic DNA was extracted from laser microdissected lesional tissue and a duplex, quantitative PCR assay was used to determine the amplification of the cyclin D1 gene relative to interferon-gamma. Cyclin D1 protein expression was determined using immunohistochemistry and counting positive nuclei by computer image analysis. We found cyclin D1 gene amplification in 41% of mild, 45% of moderate and 24% of severe OEDs. Cyclin D1 was amplified in 36% of SCC. Overexpression of cyclin D1 protein was identified in 29% of mild, 47% of moderate, 29% of severe OED's, and in 32% of SCC. Overexpression of cyclin D1 protein was identified in similar proportions of all grades of dysplasia and SCC. There were statistically significant correlations identified between gene and protein levels in all categories of disease. We concluded that amplification of the cyclin D1 gene is frequent in OED and that duplex, quantitative polymerase chain reaction is a reliable method to detect this change in routinely processed biopsies. The strong correlation between cyclin D1 gene amplification and protein levels suggests that this method may be suitable to assess cyclin D1 gene status in tissues not suitable for protein analysis.

Tissue inhibitor of metalloproteinases 1 regulation of interleukin-10 in B-cell differentiation and lymphomagenesis

Tissue inhibitors of metalloproteinases (TIMPs), first described as specific inhibitors of matrix metalloproteinases, have recently been shown to exert growth factor activities. It was previously demonstrated that TIMP-1 inhibits apoptosis in germinal center B cells and induces further differentiation. Interleukin-10 (IL-10) is reported as a vital factor for the differentiation and survival of germinal center B cells and is also a negative prognostic factor in non-Hodgkin lymphoma (NHL). However, the mechanism of IL-10 activity in B cells and the regulation of its expression are not well understood. IL-10 has been shown to up-regulate TIMP-1 in tissue macrophages, monocytes, and prostate cancer cell lines, but IL-10 modulation of TIMP-1 in B cells and the effect of TIMP-1 on IL-10 expression has not been previously studied. It was found that TIMP-1 expression regulates IL-10 levels in B cells and that TIMP-1 mediates specific B-cell differentiation steps. TIMP-1 inhibition of apoptosis is not IL-10 dependent. TIMP-1 expression in B-cell NHL correlates closely with IL-10 expression and with high histologic grade. Thus, TIMP-1 regulates IL-10 expression in B-cell NHL and, through the inhibition of apoptosis, appears responsible for the negative prognosis associated with IL-10 expression in these tumors.

EBV-associated perianal Hodgkin's disease in an HIV-positive individual

Hodgkin's disease (HD) has a higher incidence in HIV-positive individuals. It tends to occur at extranodal sites, frequently exhibits an unfavorable histological type with large numbers of neoplastic cells, and almost invariably harbors Epstein-Barr Virus (EBV). We describe a case of a 33-year-old HIV-positive man who presented with anal pain from a 4-cm mass in the anorectal canal. He had no B symptoms or peripheral lymphadenopathy. A chest X-ray was within normal limits. A biopsy showed an ulcerated mass composed of a mixed infiltrate of lymphocytes, plasma cells, eosinophils, and Reed-Sternberg (RS) cells positive for CD15 and strongly positive for CD30. They were negative for CD45 and CD20. Numerous RS cells and lymphocytes were positive for EBV RNA using the EBER-1 probe. This highly unusual presentation of HD may reflect the greater incidence of anorectal lymphoma and of extranodal HD in the HIV-positive population.

Rdp1, a novel zinc finger protein, regulates the DNA damage response of rhp51(+) from Schizosaccharomyces pombe

The Schizosaccharomyces pombe DNA repair gene rhp51(+) encodes a RecA-like protein with the DNA-dependent ATPase activity required for homologous recombination. The level of the rhp51(+) transcript is increased by a variety of DNA-damaging agents. Its promoter has two cis-acting DNA damage-responsive elements (DREs) responsible for DNA damage inducibility. Here we report identification of Rdp1, which regulates rhp51(+) expression through the DRE of rhp51(+). The protein contains a zinc finger and a polyalanine tract similar to ones previously implicated in DNA binding and transactivation or repression, respectively. In vitro footprinting and competitive binding assays indicate that the core consensus sequences (NGG/TTG/A) of DRE are crucial for the binding of Rdp1. Mutations of both DRE1 and DRE2 affected the damage-induced expression of rhp51(+), indicating that both DREs are required for transcriptional activation. In addition, mutations in the DREs significantly reduced survival rates after exposure to DNA-damaging agents, demonstrating that the damage response of rhp51(+) enhances the cellular repair capacity. Surprisingly, haploid cells containing a complete rdp1 deletion could not be recovered, indicating that rdp1(+) is essential for cell viability and implying the existence of other target genes. Furthermore, the DNA damage-dependent expression of rhp51(+) was significantly reduced in checkpoint mutants, raising the possibility that Rdp1 may mediate damage checkpoint-dependent transcription of rhp51(+).

Small lymphocytic lymphoma with perifollicular, marginal zone, or interfollicular distribution

Chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) typically involves nodal or extranodal tissues as a diffuse proliferation with pseudofollicular growth centers obliterating normal architecture. We describe 16 cases of CLL/SLL in which the neoplasm was confined to the marginal zone, perifollicular, or interfollicular regions surrounding benign lymphoid follicles in either nodal or extranodal sites. Twelve of 12 (100%) patients with adequate staging data had disseminated disease (Stage III or IV) at presentation. Eight of the 16 (50%) patients had absolute peripheral lymphocytosis (range, 5 to 30 x 10(9)/L). Pseudofollicular growth centers were identified in 14 of 16 cases (87.5%). Immunophenotypic studies revealed that the tumor cells were positive for CD20 (16/16) and CD5 (11/11) in all cases examined. CD23 was positive in 12 of 14 (86%) interpretable cases. IgM and IgD were positive in 13 of 14 (93%) and 10 of 10 (100%) interpretable cases, respectively. All cases were negative for CD3 (16/16), CD45RO (16/16), CD10 (15/15), and cyclin D1 (15/15). We conclude that CLL/SLL can have unusual patterns of involvement, including marginal zone, perifollicular, and interfollicular patterns that can be difficult to recognize histologically. Thirteen of 16 (81%) cases in this study were misinterpreted by the referring pathologists. Recognition of proliferation centers coupled with demonstration of a CD5+ CD23+ B-cell immunophenotype establishes the correct diagnosis of CLL/SLL.

Primary Hodgkin's disease of the CNS in an immunocompetent patient: a case study and review of the literature

Primary Hodgkin's disease limited to the CNS is exceedingly rare. Little is known regarding etiologic risk factors, optimal management, and prognosis. A case of Hodgkin's disease confined to the CNS, with cerebrospinal fluid negative for cytology, is described in an immunocompetent patient previously treated for hyperthyroidism with 131I. The patient underwent craniotomy, with resection of two lesions in close proximity within the parenchyma of the temporoparietal lobe. Histopathology revealed classic nodular sclerosing Hodgkin's disease, without evidence of Epstein-Barr viral infection. Treatment included radiation to the whole brain with a boost to the tumor bed. The patient made a full neurologic recovery and remains free of disease recurrence 21 months after treatment. A literature review has identified only 9 additional cases. Seven of 8 evaluable patients remain alive and free of recurrence with a median follow-up of 13 months. The risk factors for this presentation remain undefined. Although follow-up is short, radiotherapy alone appears to provide excellent disease-free survival. Chemotherapy may be reserved for patients with positive cerebrospinal fluid, extracranial disease, or subsequent relapse.

Spontaneously opening GABA(A) channels in CA1 pyramidal neurones of rat hippocampus

Spontaneous, single channel, chloride currents were recorded in 48% of cell-attached patches on neurones in the CA1 region of rat hippocampal slices. In some patches, there was more than 1 channel active. They showed outward rectification: both channel conductance and open probability were greater at depolarized than at hyperpolarized potentials. Channels activated by gamma-aminobutyric acid (GABA) in silent patches on the same neurones had similar conductance and outward rectification. The spontaneous currents were inhibited by bicuculline and potentiated by diazepam. It was concluded that the spontaneously opening channels were constitutively active, nonsynaptic GABA(A) channels. Such spontaneously opening GABA(A) channels may provide a tonic inhibitory mechanism in these cells and perhaps in other cells that have GABA(A) receptors although not having a GABA(A) synaptic input. They may also be a target for clinically useful drugs such as the benzodiazepines.

Vitamin E status of infants at birth

Preterm infants may be susceptible to chronic lung disease and retinopathy of prematurity because of deficient antioxidant mechanisms including deficiency of vitamin E. The aim of this study was to evaluate the status of the antioxidant vitamin E among preterm and term livebirths. Umbilical cord blood samples collected from 40 preterm and 180 term babies were analyzed for vitamin E levels using high performance liquid chromatography. Linear regression analysis was used to examine the relationship of vitamin E with gestational age, birth weight and appropriateness of weight for gestational age. The median vitamin E level of preterm babies (2.61 mg/L) was not significantly different from that of term babies (2.77 mg/L), p = 0.2. Linear regression analysis demonstrated a weak but statistically significant correlation between cord blood vitamin E levels and gestational age (r = 0.14, p = 0.046). Vitamin E levels did not correlate with birth weight or weight for gestational age. Preterm babies had a higher incidence of vitamin E deficiency compared to term babies (38% v 19%, p = 0.02). Our findings lead us to conclude that vitamin E accumulates in the fetus throughout the third trimester so that preterm infants are likely to have vitamin E deficiency.

Pathological findings in human autoimmune lymphoproliferative syndrome

The defects in lymphocyte apoptosis that underlie the autoimmune lymphoproliferative syndrome (ALPS) are usually attributable to inherited mutations of the CD95 (Fas) gene. In this report, we present the histopathological and immunophenotypic features seen in the lymph nodes (n = 16), peripheral blood (n = 10), bone marrow (n = 2), spleen (n = 3), and liver (n = 2) from 10 patients with ALPS. Lymph nodes showed marked paracortical hyperplasia. Interfollicular areas were expanded and populated by T cell receptor-alphabeta CD3+ CD4-CD8- (double-negative, DN) T cells that were negative for CD45RO. CD45RA+ T cells were increased in all cases studied. The paracortical infiltrate was a result of both reduced apoptosis and increased proliferation, as measured by in situ detection of DNA fragmentation and staining with MIB-1, respectively. The paracortical proliferation may be extensive enough to suggest a diagnosis of malignant lymphoma. Many of the paracortical lymphocytes expressed markers associated with cytotoxicity, such as perforin, TIA-1, and CD57. CD25 was negative. In addition, most lymph nodes exhibited florid follicular hyperplasia, often with focal progressive transformation of germinal centers; in some cases, follicular involution was seen. A polyclonal plasmacytosis also was present. The spleens were markedly enlarged, more than 10 times normal size. There was expansion of both white pulp and red pulp, with increased DN T cells. DN T cells also were observed in liver biopsies exhibiting portal triaditis. In the peripheral blood, the T cells showed increased expression of HLA-DR and CD57 but not CD25. CD45RA+ T cells were increased in the four cases studied. Polyclonal B cell lymphocytosis with expansion of CD5+ B cells was a characteristic finding. Taken together, the histopathological and immunophenotypic findings, particularly in lymph nodes and peripheral blood, are sufficiently distinctive to suggest a diagnosis of ALPS. Of note, two affected family members of one proband developed lymphoma (T-cell-rich B-cell lymphoma and nodular lymphocyte predominance Hodgkin's disease, respectively).

Homozygous deletions at chromosome 9p21 involving p16 and p15 are associated with histologic progression in follicle center lymphoma

Low-grade follicle center lymphoma (LGFCL) is characterized genetically by the t(14;18) translocation and an indolent clinical course. Histologic progression from LGFCL to an aggressive diffuse large B-cell lymphoma (DLCL) occurs in 60% to 80% of cases, and this transformation is associated with the accumulation of secondary genetic alterations. Using 10 polymorphic microsatellite markers spanning the chromosome 9p21 region harboring the p15 (p15(INK4B)/MTS-2/CDKN2B) and p16 (p16(INK4A)/MTS-1/CDKN2) tumor-suppressor gene loci, we analyzed 11 matched pairs of LGFCL and their corresponding progressed DLCL biopsies for loss of heterozygosity and homozygous deletions at 9p21. A comparative multiplex polymerase chain reaction assay was also used for the detection of homozygous deletions. Deletions were identified in 8 of the 11 cases studied (73%): 6 homozygous (54%) and 2 hemizygous (18%). The deletions were identified exclusively in the progressed DLCL biopsies. Immunohistochemical studies showed an excellent correlation with the results from the genetic analyses. Of the 9 matched pairs of LGFCL and progressed DLCL with interpretable immunohistochemical staining, 9 of 9 (100%) of the LGFCL showed diffuse reactivity for p16. Four of the 9 (44%) immunohistochemically evaluable cases of progressed DLCL showed loss of or, in 1 case, markedly diminished p16 expression. All 4 of these cases correspondingly showed homozygous deletions at 9p21. Five of the 9 progressed DLCL cases showed p16 expression and demonstrated retention of one or both 9p21 alleles by genetic analysis. This is the first longitudinal series examining sequential biopsy specimens of low-grade and progressed FCL for genetic loss at 9p21 encompassing the p16 and p15 loci. The high frequency and exclusive occurrence of deletions involving p16 in the progressed DLCLs suggests that genetic loss at 9p21 targeting p16 and/or p15 is an important secondary genetic event in the histologic progression of FCL.

Proteolytic activity of human non-Hodgkin's lymphomas

This study was conducted to assess the net proteolytic activity of human non-Hodgkin's lymphomas (NHLs). We have compared the extracellular matrix (ECM)-degradative abilities of human NHLs, reactive lymphoid hyperplasias, and established lymphoid cell lines using Matrigel invasion and elastin degradation assays. The inhibition studies allowed identification of the classes of proteinases involved in ECM degradation. Our results indicate that lymphocytes and other leukocytes derived from both human NHLs and reactive lymphoid hyperplasias are capable of Matrigel penetration, but only cells derived from the high-grade human NHLs degrade elastin in vitro. Established lymphoid cell lines (both malignant and Epstein-Barr virus immortalized) do not produce MMP-9, do not penetrate the Matrigel, and do not degrade elastin. Moreover, in human NHLs, elastolytic activity is blocked by metalloproteinase inhibitors, while inhibitors of the other classes of proteolytic enzymes have only minor effects. This study identifies metalloproteinases as the most important class of proteinases involved in ECM degradation by NHLs. The previous studies suggest that, within this class, MMP-9 represents the key enzyme that plays a role in the biological aggressiveness of human NHLs.

Clincal, immunologic, and genetic features of an autoimmune lymphoproliferative syndrome associated with abnormal lymphocyte apoptosis

Programmed cell death (apoptosis) of activated lymphocytes is critical to immune homeostasis. The cell surface protein Fas (CD95) and its ligand play a pivotal role in regulating lymphocyte apoptosis, and defective expression of either Fas or Fas ligand results in marked over accumulation of mature lymphocytes and autoimmune disease in mice. The results of recent studies suggest that defective lymphocyte apoptosis caused by mutations of the Fas gene can result in a severe autoimmune lymphoproliferative syndrome (ALPS) in humans. To define the clinical, genetic, and immunologic spectrum of ALPS, 9 patients and their families were extensively evaluated with routine clinical studies, lymphocyte phenotyping, genotyping, and in vitro assays for lymphocyte apoptosis. Individual patients were followed up for 3 months to 6 years. ALPS was identified in 9 unrelated children as manifested by moderate to massive splenomegaly and lymphadenopathy, hypergammaglobulinemia, autoimmunity, B-cell lymphocytosis, and the expansion of an unusual population of CD4- CD8- T cells that express the alpha/beta T-cell receptor (TCR). All patients showed defective lymphocyte apoptosis in vitro. Heterozygous mutations of the Fas gene were detected in 8 patients. One ALPS patient lacked a Fas gene mutation. Healthy relatives with Fas mutations were identified in 7 of 8 ALPS kindreds. These relatives also showed in vitro abnormalities of Fas-mediated lymphocyte apoptosis, but clinical features of ALPS were not present in the vast majority of these individuals. ALPS is a unique clinical syndrome in which in vitro abnormalities of lymphocyte apoptosis are associated with abnormal lymphoproliferation and autoimmunity. These findings provide evidence that apoptosis of activated lymphocytes is an important mechanism for maintaining immunologic homeostasis and self-tolerance in humans. Fas gene mutations account for impaired lymphocyte apoptosis in only a subset of patients with ALPS.