Protein arginine N-methyltransferase 4 (PRMT4) contributes to lymphopenia in experimental sepsis

BACKGROUND

One hallmark of sepsis is the reduced number of lymphocytes, termed lymphopenia, that occurs from decreased lymphocyte proliferation or increased cell death contributing to immune suppression. Histone modification enzymes regulate immunity by their epigenetic and non-epigenetic functions; however, the role of these enzymes in lymphopenia remains elusive.

METHODS

We used molecular biological approaches to investigate the high expression and function of a chromatin modulator protein arginine N-methyltransferase 4 (PRMT4)/coactivator-associated arginine methyltransferase 1 in human samples from septic patients and cellular and animal septic models.

RESULTS

We identified that PRMT4 is elevated systemically in septic patients and experimental sepsis. Gram-negative bacteria and their derived endotoxin lipopolysaccharide (LPS) increased PRMT4 in B and T lymphocytes and THP-1 monocytes. Single-cell RNA sequencing results indicate an increase of PRMT4 gene expression in activated T lymphocytes. Augmented PRMT4 is crucial for inducing lymphocyte apoptosis but not monocyte THP-1 cells. Ectopic expression of PRMT4 protein caused substantial lymphocyte death via caspase 3-mediated cell death signalling, and knockout of PRMT4 abolished LPS-mediated lymphocyte death. PRMT4 inhibition with a small molecule compound attenuated lymphocyte death in complementary models of sepsis.

CONCLUSIONS

These findings demonstrate a previously uncharacterised role of a key chromatin modulator in lymphocyte survival that may shed light on devising therapeutic modalities to lessen the severity of septic immunosuppression.

CD4+ T-Cell Dysfunction in Severe COVID-19 Disease Is Tumor Necrosis Factor-α/Tumor Necrosis Factor Receptor 1-Dependent

Rationale: Lymphopenia is common in severe coronavirus disease (COVID-19), yet the immune mechanisms are poorly understood. As inflammatory cytokines are increased in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, we hypothesized a role in contributing to reduced T-cell numbers. Objectives: We sought to characterize the functional SARS-CoV-2 T-cell responses in patients with severe versus recovered, mild COVID-19 to determine whether differences were detectable. Methods: Using flow cytometry and single-cell RNA sequence analyses, we assessed SARS-CoV-2-specific responses in our cohort. Measurements and Main Results: In 148 patients with severe COVID-19, we found lymphopenia was associated with worse survival. CD4⁺ lymphopenia predominated, with lower CD4⁺/CD8⁺ ratios in severe COVID-19 compared with patients with mild disease (P < 0.0001). In severe disease, immunodominant CD4⁺ T-cell responses to Spike-1 (S1) produced increased in vitro TNF-α (tumor necrosis factor-α) but demonstrated impaired S1-specific proliferation and increased susceptibility to activation-induced cell death after antigen exposure. CD4⁺TNF-α⁺ T-cell responses inversely correlated with absolute CD4⁺ counts from patients with severe COVID-19 (n = 76; R = -0.797; P < 0.0001). In vitro TNF-α blockade, including infliximab or anti-TNF receptor 1 antibodies, strikingly rescued S1-specific CD4⁺ T-cell proliferation and abrogated S1-specific activation-induced cell death in peripheral blood mononuclear cells from patients with severe COVID-19 (P < 0.001). Single-cell RNA sequencing demonstrated marked downregulation of type-1 cytokines and NFκB signaling in S1-stimulated CD4⁺ cells with infliximab treatment. We also evaluated BAL and lung explant CD4⁺ T cells recovered from patients with severe COVID-19 and observed that lung T cells produced higher TNF-α compared with peripheral blood mononuclear cells. Conclusions: Together, our findings show CD4⁺ dysfunction in severe COVID-19 is TNF-α/TNF receptor 1-dependent through immune mechanisms that may contribute to lymphopenia. TNF-α blockade may be beneficial in severe COVID-19.

Association of the systemic host immune response with acute hyperglycemia in mechanically ventilated septic patients

Hyperglycemia during sepsis is associated with increased organ dysfunction and higher mortality. The role of the host immune response in development of hyperglycemia during sepsis remains unclear. We performed a retrospective analysis of critically ill adult septic patients requiring mechanical ventilation (n = 153) to study the relationship between hyperglycemia and ten markers of the host injury and immune response measured on the first day of ICU admission (baseline). We determined associations between each biomarker and: (1) glucose, insulin, and c-peptide levels at the time of biomarker collection by Pearson correlation; (2) average glucose and glycemic variability in the first two days of ICU admission by linear regression; and (3) occurrence of hyperglycemia (blood glucose>180mg/dL) by logistic regression. Results were adjusted for age, pre-existing diabetes mellitus, severity of illness, and total insulin and glucocorticoid dose. Baseline plasma levels of ST2 and procalcitonin were positively correlated with average blood glucose and glycemic variability in the first two days of ICU admission in unadjusted and adjusted analyses. Additionally, higher baseline ST2, IL-1ra, procalcitonin, and pentraxin-3 levels were associated with increased risk of hyperglycemia. Our results suggest associations between the host immune response and hyperglycemia in critically ill septic patients particularly implicating the interleukin-1 axis (IL-1ra), the interleukin-33 axis (ST2), and the host response to bacterial infections (procalcitonin, pentraxin-3).

Single cell RNA sequencing reveals novel inflammatory mechanisms of human acute respiratory distress syndrome

The acute respiratory distress syndrome (ARDS) is a common etiology of acute respiratory failure that results from overwhelming pulmonary inflammation. Since prior bulk RNA sequence analyses have provided limited insights into ARDS pathogenesis, we used the approach of single cell RNA sequencing (scRNA-seq) to probe ARDS at a higher resolution. Towards this end, scRNA-seq data of peripheral blood mononuclear cells (PBMCs) of patients with pneumonia and sepsis with early ARDS were compared to that of sepsis patients who did not develop ARDS. We detected a previously unrecognized reduced frequency of NK cells in the PBMCs of ARDS patients, which also showed complete loss of IFNGR1 expression. Monocyte clusters from ARDS patients revealed multiple distinguishing characteristics in comparison to monocytes from patients without ARDS. This included a pro-inflammatory signature with up-regulation of multiple type I IFN-induced genes, especially in CD16+ cells. To generate an ARDS risk score, we identified 29 differentially expressed genes in the monocytes of these patients, 17 of which showed a similar profile in cells of patients in independent cohorts. Genes with increased expression in monocytes that may have relevance in ARDS pathogenesis include RAB11A, known to inhibit neutrophil efferocytosis, ATP2B1, a calcium pump that exports Ca2+ implicated in endothelial barrier disruption, and SPARC, associated with processing of pro-collagen to collagen. Together, our findings identify molecules that are likely involved in ARDS pathogenesis that may inform biomarker and therapeutic development.

245. Plasma and Respiratory Specimen Metagenomic Sequencing for the Diagnosis of Severe Pneumonia in Mechanically-Ventilated Patients

Background

Metagenomic sequencing of respiratory microbial communities may overcome the limitations of culture-based pneumonia diagnostics. Nonetheless, respiratory metagenomics requires high-quality specimens, may miss deep-seated infections and cannot distinguish colonization from infection. Plasma microbial cell-free DNA (mcfDNA) sequencing may offer a noninvasive alternative for culture-independent diagnosis and help refine interpretations of respiratory metagenomics.

Methods

We obtained concurrent plasma and endo-tracheal aspirate (ETA) samples from 29 mechanically-ventilated patients (15 culture-positive, 11 culture-negative pneumonia, 3 uninfected control patients). We performed plasma mcfDNA sequencing (Karius^®Test, Redwood City, CA) and ETA metagenomics (MiNION, Oxford Nanopore Technologies). We compared sequencing results with clinical microbiologic cultures for identified DNA pathogens.

Results

Uninfected control patients had a negative signal for mcfDNA in plasma and oral bacteria in ETA specimens. In culture-positive pneumonia samples, Karius testing identified a median of 2 pathogens per sample (range 0–10), which were concordant with clinical isolates in 11/15 (73%) cases (figure). In 5/11 (45%) of concordant cases, Karius and MiNION suggested polymicrobial infections with additional pathogens not identified by cultures. In culture-negative cases, Karius detected potential pathogens in 8/11 (73% cases), which matched the species identified in ETA specimens by MiNION. In cases of clinical aspiration, Karius detected more organisms (median 8, range 0–14) per sample mainly consisting of oral origin bacteria compared with cases without history of aspiration (median 1, range 0–6, P = 0.04).

Conclusion

Metagenomic sequencing in plasma and ETA samples showed good concordance between the blood and lung compartments as well as with culture results in pneumonia patients. Metagenomics revealed potential pathogens missed by cultures in ~75% of culture-negative pneumonias and suggested polymicrobial infections especially in cases with aspiration. Further research is needed to evaluate the clinical utility of real-time metagenomics for pneumonia diagnosis in mechanically ventilated patients.

Disclosures

All authors: No reported disclosures.

Cyclin dependent protein kinases and stress responses in plants

Plants have to adjust, grow and establish themselves in various changing environmental conditions. Additionally, the sessile life-style of plants requires the development of response mechanisms for their adaptation in such environmental cues. Under biotic and abiotic stress, plant growth is negatively affected mainly as a result of cell cycle inhibition. The perception of stress involves the activation of signaling cascades that result in a prolonged S-phase and delayed entry into mitosis. Although the molecular interactions that link the cell cycle machinery to perception of stress are not fully understood, recent studies indicated the involvement of Cyclin Dependent Kinases (CDKs) in the plant response machinery. CDKs are core cell cycle regulators but their activity has been implicated in additional diverse cellular processes. Here we review the impact of different types of abiotic stress on plant cell cycle progression and CDK activity, and discuss the contribution of CDK function in the signaling control of stress tolerance.

Against pragmatism: on efficacy, effectiveness and the real world

Explanatory and pragmatic trials represent ends of a continuum of attitudes about clinical trial design. Recent literature argues that pragmatic trials are more informative about clinical care in the real world. Although there is place for more pragmatic studies to inform clinical practice and health policy decision-making, we are concerned that it is generally under-appreciated that extrapolating the results of broadly inclusive pragmatic trials to the care of real patients may often be as problematic as extrapolating the results of narrowly focused explanatory or efficacy trials. Simplistic interpretation of pragmatic trials runs the risk of driving harmful policies.

ACE (I/D) polymorphism and response to treatment in coronary artery disease: a comprehensive database and meta-analysis involving study quality evaluation

BACKGROUND

The role of angiotensin-converting enzyme (ACE) gene insertion/deletion (I/D) polymorphism in modifying the response to treatment modalities in coronary artery disease is controversial.

METHODS

PubMed was searched and a database of 58 studies with detailed information regarding ACE I/D polymorphism and response to treatment in coronary artery disease was created. Eligible studies were synthesized using meta-analysis methods, including cumulative meta-analysis. Heterogeneity and study quality issues were explored.

RESULTS

Forty studies involved invasive treatments (coronary angioplasty or coronary artery by-pass grafting) and 18 used conservative treatment options (including anti-hypertensive drugs, lipid lowering therapy and cardiac rehabilitation procedures). Clinical outcomes were investigated by 11 studies, while 47 studies focused on surrogate endpoints. The most studied outcome was the restenosis following coronary angioplasty (34 studies). Heterogeneity among studies (p < 0.01) was revealed and the risk of restenosis following balloon angioplasty was significant under an additive model: the random effects odds ratio was 1.42 (95% confidence interval:1.07-1.91). Cumulative meta-analysis showed a trend of association as information accumulates. The results were affected by population origin and study quality criteria. The meta-analyses for the risk of restenosis following stent angioplasty or after angioplasty and treatment with angiotensin-converting enzyme inhibitors produced non-significant results. The allele contrast random effects odds ratios with the 95% confidence intervals were 1.04(0.92-1.16) and 1.10(0.81-1.48), respectively. Regarding the effect of ACE I/D polymorphism on the response to treatment for the rest outcomes (coronary events, endothelial dysfunction, left ventricular remodeling, progression/regression of atherosclerosis), individual studies showed significance; however, results were discrepant and inconsistent.

CONCLUSION

In view of available evidence, genetic testing of ACE I/D polymorphism prior to clinical decision making is not currently justified. The relation between ACE genetic variation and response to treatment in CAD remains an unresolved issue. The results of long-term and properly designed prospective studies hold the promise for pharmacogenetically tailored therapy in CAD.

ENDOSPERM DEFECTIVE1 Is a Novel Microtubule-Associated Protein Essential for Seed Development in Arabidopsis

Early endosperm development involves a series of rapid nuclear divisions in the absence of cytokinesis; thus, many endosperm mutants reveal genes whose functions are essential for mitosis. This work finds that the endosperm of Arabidopsis thaliana endosperm-defective1 (ede1) mutants never cellularizes, contains a reduced number of enlarged polyploid nuclei, and features an aberrant microtubule cytoskeleton, where the specialized radial microtubule systems and cytokinetic phragmoplasts are absent. Early embryo development is substantially normal, although occasional cytokinesis defects are observed. The EDE1 gene was cloned using a map-based approach and represents the pioneer member of a conserved plant-specific family of genes of previously unknown function. EDE1 is expressed in the endosperm and embryo of developing seeds, and its expression is tightly regulated during cell cycle progression. EDE1 protein accumulates in nuclear caps in premitotic cells, colocalizes along microtubules of the spindle and phragmoplast, and binds microtubules in vitro. We conclude that EDE1 is a novel plant-specific microtubule-associated protein essential for microtubule function during the mitotic and cytokinetic stages that generate the Arabidopsis endosperm and embryo.

Angiotensin-converting enzyme insertion/deletion gene polymorphic variant as a marker of coronary artery disease: a meta-analysis

BACKGROUND

Many studies have investigated the association between the angiotensin-converting enzyme (ACE) gene insertion (I)/deletion (D) polymorphic variant and coronary artery disease (CAD). However, the evidence is inadequate to draw robust conclusions because most studies were generally small and conducted in heterogeneous samples. To shed light on these inconclusive findings, we conducted a meta-analysis of studies relating the ACE I/D polymorphic variant to the risk of CAD.

METHODS

We searched the PubMed database for English-language articles on CAD in humans. We estimated summary odds ratios and explored potential sources of heterogeneity and bias.

RESULTS

The 118 studies chosen for the analysis involved 43 733 cases with CAD and 82 606 controls. The heterogeneity between studies was significant. When we compared homozygotes with the D and I alterations, the ACE I/D polymorphic variant was associated with a 25% increased risk of CAD (odds ratio, 1.25; 95% confidence interval, 1.16-1.35). Subgroup analyses for myocardial infarction, diabetes mellitus, male sex, white race, East Asian subjects, and Turkish subjects showed significant associations. No association was found in other racial/ethnic groups, in women, in premature cases, or in cases with low levels of risk factors. The major sources of heterogeneity were due to racial/ethnic diversity, genotyping procedure, and age matching. Cumulative meta-analysis for the allelic contrast showed a trend of association as information accumulated. There was a differential magnitude of effect in large vs small studies.

CONCLUSIONS

The meta-analysis demonstrated evidence of a modest positive association between ACE I/D polymorphic variant and CAD. The meta-analysis also highlights the heterogeneity of reported results, considerable gaps in research, and the need for future studies focused on certain high-risk patient populations.

A cyclin-dependent protein kinase, CDKC2, colocalizes with and modulates the distribution of spliceosomal components in Arabidopsis

Cyclin-dependent kinases (CDKs) play key regulatory roles in diverse cellular functions, including cell-cycle progression, transcription and translation. In plants, CDKs have been classified into several groups, named A through to G, but the functions of most are poorly characterized. CDKCs are known to phosphorylate the C-terminal domain (CTD) of RNA polymerase II (RNAP II), and therefore the CDKC-cyclinT (CycT) complex may have a role similar to the animal CDK9-CycT complex of the positive transcription elongation factor b (P-TEFb). However, we found that the predicted structure of the Arabidopsis CDKC2 protein is more similar to the mammalian cdc2-related kinase, CRK7, than to CDK9. CRK7 is proposed to link transcription with splicing, and CDKC2 contains all the structural features of CRK7 that make the latter distinct from CDK9. Consistent with this, we show that GFP-CDKC2 fusion proteins co-localize with spliceosomal components, that the expression of CDKC2 modifies the location of these components, and that co-localization was dependent on the transcriptional status of the cells and on CDKC2-kinase activity. We propose, therefore, that the Arabidopsis CDKC2 combines the functions of both CRK7 and CDK9, and could also couple splicing with transcription.

Genetic variation associated with ischemic heart failure: a HuGE review and meta-analysis

The ischemic etiology of heart failure is an independent prognostic factor associated with worse long-term outcome. Recent evidence indicates a role for genetic susceptibility to ischemic heart failure. The authors systematically reviewed all known case-control studies that investigated the association between genetic variants and ischemic heart failure. Twenty-two articles, which examined 24 gene polymorphisms, were identified. In 22 polymorphisms, the variant form had a functional effect. Twenty-two polymorphisms were variants of genes involved in the maladaptive neurohormonal activation. Seven polymorphisms (ACE I/D, AGT M235T, ADRA2C Del322-325, ADRB2 Arg16Gly, ADRB2 Gln27Glu, EDN1 Lys198Asn, VEGF G-405C) showed a significant association in individual studies. Five polymorphisms (ACE I/D, ADRB1 Arg389Gly, ADRB2 Arg16Gly, ADRB2 Gln27Glu, TNF G308A) were examined by more than one study, and meta-analyses were performed. The meta-analyses showed no significant sign of heterogeneity. In all settings, there was no significant association, except for polymorphism ADRB2 Arg16Gly under a recessive model (fixed-effects odds ratio = 1.32, 95% confidence interval: 1.05, 1.65). Taking into account that ischemic heart failure is a complex disease with multifactorial etiology, a minor contributing pathogenetic role of the investigated gene polymorphisms cannot be totally excluded. Case-control studies that investigate gene-gene and gene-environment interactions might further elucidate the genetics of ischemic heart failure.

Genome-wide scans meta-analysis for pulse pressure

Genome scans for identifying susceptibility loci for pulse pressure have produced inconclusive results. A heterogeneity-based genome search meta-analysis was applied to available genome-scan data on pulse pressure. A genome search meta-analysis divides the whole genome into 120 bins and identifies bins that rank high on average in terms of linkage statistics across genome scans unweighted or weighted by study size. The significance of each bin's average rank (right-sided test) and heterogeneity among studies (left-sided test) was calculated using a Monte Carlo test. The meta-analysis involved 7 genome scans, 3 consisting of subjects of European descent. Of the 120 bins, 5 bins had significant average rank (P(rank)<or=0.05) by either unweighted or weighted analyses, 4 of which (bins 21.2: 21q22.11 to 21q22.3, 18.3: 18q12.2 to 18q21.33, 18.4: 18q21.33 to 18q23, and 6.2: 6p22.3 to 6p21.1) were significant by both. In subjects of European descent, 3 bins (22.1: 22q11.1 to 22q12.3, 22.2: 22q12.3 to 22q13.3, 10.4: 10q22.1 to 10q23.32) had P(rank)<or=0.05 with both unweighted and weighted analyses. Bin 10.4 showed low heterogeneity (P(Q)=0.04). None of the bins showed low heterogeneity (P(Q)>0.05), indicating variation in the strength of association. Further investigation of these regions may help to direct the identification of candidate genes for pulse pressure variation.

Identification of chromosomal regions linked to premature myocardial infarction: a meta-analysis of whole-genome searches

Myocardial infarction (MI) is a complication of coronary artery disease and the leading cause of death in the Western world. MI is considered a distinct phenotype with an increased genetic component for its premature type. MI's exact inheritance pattern is still unknown. Genome searches for identifying susceptibility loci for premature MI produced inconclusive or inconsistent results. Thus, a genome search meta-analysis (GSMA) was applied to available genome search data on premature MI. GSMA is a non-parametric method to identify genetic regions that rank high, on average in terms of linkage statistics across genome searches unweighted or weighted by study size. The significance of each region's average and heterogeneity, unadjusted or adjusted by neighbouring average simulated ranks, was calculated using a Monte Carlo test. The meta-analysis involved five genome searches in Caucasians. Eight regions (6p22.3-6p21.1, 14p13-14q13.1, 13q33.1-13q34, 5p15.33-5p15.1, 8q13.2-8q22.2, 1p36.21-1p35.2, 12q24.31-12q24.33, 8q24.21-8q24.3) were found to have significant average rank by either unweighted or weighted analyses. In addition, region 8q24.21-8q24.3 produced significant low heterogeneity (P (unadjusted)=0.03 and P (adjusted)=0.05). Four regions (6p22.3-6p21.1, 14p13-14q13.1, 8q13.2-8q22.2, 8q24.21-8q24.3) were not identified by the individual studies. The meta-analysis suggests that these four regions should be further investigated for genes that confer susceptibility to MI.

Endothelial NO synthase gene polymorphisms and hypertension: a meta-analysis

Studies investigated the association between endothelial NO synthase gene polymorphisms and hypertension-reported contradicted or nonconclusive results. A meta-analysis of 35 genetic association studies that examined the relation between hypertension and the G894T, 4a/b, T786C, and G23T polymorphisms of the endothelial nitric oxide synthase gene was carried out. Subgroup analysis by ethnicity and potential sources of heterogeneity and bias were explored. The meta-analysis included genotype data on 7779/10 498, 2216/3222, 2491/3913, and 833/587 cases/controls for G894T, 4b/a, T786C, and G23T, respectively. For the 4b/a polymorphism, overall, the heterogeneity between studies was not significant (P=0.82), and the allele b was associated with a 15% decreased risk of hypertension relative to allele a (odds ratio: 0.85; 95% CI: 0.74 to 0.98). Overall and in whites, the recessive model for allele b produced significant results (odds ratios: 0.78; 95% CI: 0.68 to 0.90 and OR: 0.76 95% CI: 0.62 to 0.92, respectively), whereas the dominant model produced nonsignificant results. In studies involved East Asians and blacks, an association was not demonstrated. Regarding the G894T, T768C, and G23T polymorphisms, in no case (ie, overall, in whites, or in East Asians) was a statistically significant association and heterogeneity found. There was no substantial source of bias in the selected studies. In conclusion, there is evidence of association only between 4b/a polymorphism and hypertension; however, studies exploring combinations of the polymorphisms may help us better understand the genetics of hypertension.

Heterogeneity-based genome search meta-analysis for preeclampsia

Preeclampsia is a pregnancy-related disorder that causes maternal and fetal morbidity and mortality. Its exact inheritance pattern is still unknown, and genome searches for identifying susceptibility loci for preeclampsia have thus far produced inconclusive or inconsistent results. We performed a heterogeneity-based genome search meta-analysis (HEGESMA) that synthesized the available genome scan data on preeclampsia. HEGESMA identifies genetic regions (bins) that rank highly on average in terms of linkage statistics across genome scans (searches). The significance of each bin's average rank and heterogeneity across scans was calculated using Monte Carlo tests. The meta-analysis involved four genome-scans on general preeclampsia and five scans on severe preeclampsia. In general preeclampsia, 13 bins had significantly high average rank (Prank< 0.05) by either unweighted or weighted analyses, while four of them (2p11.2-2q21.1, 9q21.32-9q31.2, 2p15-2p11.2, 2q32.1-2q35) were formally significant by both analyses. Heterogeneity of bin 2.8 (2q32.1-2q35) was significantly low in both unweighted and weighted analysis (PQ< 0.01). In severe preeclampsia, 10 bins had significantly high average rank by either unweighted or weighted analyses and five of them (3q11.1-3q21.2, 2q37.1-2q37.3, 18p11.32-18p11.22, 2p15-2p11.2, 7q34-7q36.3) were significant by both analyses. Bin 2q37.1-2q37.3 showed marginal low heterogeneity in unweighted and weighted analysis (PQ= 0.06). Results should be interpreted with caution as the p values were modest. Further investigation of these regions by genotyping with additional markers and families may help to direct the identification of candidate genes for preeclampsia.

Anaemia as a symptom of right colon cancer

BACKGROUND

The aim of our study is to determine the proportion of iron deficiency anaemia in patients with right colon cancer at diagnosis and to remind of the need of investigation of the large bowel in patients presenting with anaemia.

PATIENTS AND METHODS

From 1988 to 2003, 86 patients with right colon cancer underwent operative management.

RESULTS

Seventy-five patients (87.2%) with right colon cancer had anaemia at diagnosis. The mean Ht value was 33.00% (ranging from 16 to 47%).

CONCLUSIONS

Iron deficiency anaemia is a common symptom of right colon cancer. During the evaluation of patients with iron deficiency anaemia, examination of the right colon is needed.

Alarming atrioventricular block and mitral valve prolapse in the Kearns-Sayre syndrome

Kearns-Sayre syndrome (KSS) is a multisystem mitochondrial disorder characterized by the invariant triad: onset before 20, progressive external ophthalmoplegia and pigmentary retinal degeneration, plus at least one of the following: complete (or not) heart block, cereberal dysfunction and CSF protein above 100 mg/dl. Autopsies from patients with KSS revealed widespread tissue distribution mtDNA deletions. These deletions result in significantly lower activities of the enzymes of the respiratory chain. The same deletion of mitochondrial DNA present in skeletal muscle is found in myocardial tissue. An 18-year-old girl diagnosed with the KSS was admitted to our hospital because of an upper respiratory tract infection and dysphagia. ECG showed cardiac conduction defects. The patient had no history of syncope. At her surface ECG there was a complete RBBB (QRS duration approximately 130 ms), a clockwise rotation with an axis of approximately 90 degrees and a slight QT prolongation (420 ms). Echocardiography showed prolapse with thickening and degeneration of both mitral valve leaflets but without mitral regurgitation. The patient was started on a diet rich in potassium and pharmaceutical therapy with magnesium oxide (240 mg of elemental Mg p.o. per day), 1 g of calcium carbonate t.i.d., vitamin D (calcitriol 0.25 microg p.o. per day) and coenzyme Q(10) 100 mg daily and discharged 6 days later with slightly improved biochemical profile but apparent clinical improvement. Urgent pacemaker implantation was decided but unfortunately the patient died due to acute cardiac arrest 10 days later.

Evaluation of tear break-up time, Schirmer's-I test and rose bengal staining as confirmatory tests for keratoconjunctivitis sicca

The tear break-up time (BUT), Schirmer's I test (S-I) and slit lamp examination after rose Bengal staining (RBS) are simple tests for evaluation of keratoconjunctivitis sicca (KCS). Discrepancies, however, regarding the range of normal values and the specificity and sensitivity of these methods prompted us to reevaluate them in 81 primary Sjögren's syndrome patients (Ss) and 276 normal volunteers. In normal volunteers, BUT values ranged from 4 sec. to 32 sec. (means +/- SD: 13 +/- 6 sec.) and in primary Ss from 1 sec. to 15 sec. (means +/- SD: 7 +/- 3 sec.). Ninety five percent (95%) of the values from primary Ss patients were below 12 sec. Forty two percent (42%) of the values obtained from normal individuals fall within this range. Schirmer's I test values in normal individuals ranged from 0 mm/5 min. to 30 mm/5 min. (means +/- SD: 10 +/- 9 mm) and in primary Ss patients from 0 mm/5 min. to 30 mm/5 min. (means +/- SD: 4 +/- 7 mm.). Ninety five percent (95%) of the primary Ss patients' values were below 19 mm/5 min. Sixty eight percent (68%) of the normal individual values fall into this range. Rose Bengal staining values ranged in normals from 0 to 7 (means +/- SD: 1 +/- 1) and in primary Ss patients from 1 to 8 (means +/- SD: 5 +/- 2). Ninety five percent (95%) of the primary Ss patients' values were above 2. Only 7% of normal individual values fall into this range. From these data we conclude that rose Bengal staining is the best test for evaluation of keratoconjunctivitis sicca.