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Petr Jarolim

Publications and source records attributed to Petr Jarolim.

16 recordsLinked to original sources
PubMed2006

T-bet controls pathogenicity of CTLs in the heart by separable effects on migration and effector activity.

CD8+ CTL contribute to the pathogenesis of myocarditis and cardiac allograft rejection. Using a transgenic model of myocarditis, we examined the role of the transcription factor T-bet in the differentiation of pathogenic cardiac Ag-specific CTL. We demonstrate that T-bet-deficient CTL are significantly impaired in their ability to cause disease, despite intact proliferation and activation phenotypes. In the absence of T-bet, there is markedly reduced expression of the chemokine receptor CXCR3, and CXCR3-gene knockout CTL are significantly less pathogenic than control CTL. Retroviral-mediated CXCR3 expression in T-bet-deficient CD8+ T cells reconstitutes their ability to infiltrate but not to damage the heart, establishing that CD8+ T cell pathogenicity is related to T-bet-dependent CXCR3 expression, reduced cytotoxicity, and enhanced regulation. These findings highlight the potential therapeutic benefit of targeting T-bet-regulated gene expression and CXCR3-dependent migration in immune-mediated heart disease.

Animals↗
PubMed2006

Abrogation of functional selectin-ligand expression reduces migration of pathogenic CD8+ T cells into heart.

CD8+ T cells are involved in autoimmune and infectious myocarditis and cardiac allograft rejection. The role of selectins in cardiac recruitment of CD8+ T cells is not understood. In this study, the contribution of T cell selectin ligands to effector CD8+ T cell recruitment into the heart was examined using a model of myocarditis, which depends on transfer of OVA peptide-specific CD8+ T cells (OT-I) into mice (CMy-mOva) that express OVA in the heart. alpha-(1,3)-Fucosyltransferase (FucT)-VII-deficient OT-I cells displayed over a 95% reduction in their ability to interact with P-selectin under flow conditions in vitro, compared with wild-type OT-I cells. Interaction of FucT-VII-deficient OT-I cells with E-selectin was reduced approximately 50%. FucT-VII-deficient OT-I cells were also less efficiently recruited into a dermal site of Ag and adjuvant injection. Significantly, FucT-VII-deficient OT-I cells were also impaired in their ability to migrate into CMy-mOva hearts, compared with wild-type OT-I cells. Transfer of FucT-VII-deficient T cells caused less severe early myocarditis and myocyte damage than transfer of wild-type T cells. Combined FucT-IV/VII-deficient OT-I cells displayed a more profound reduction in E-selectin interactions in vitro compared with FucT-VII-deficient T cells, and the FucT-IV/VII-deficient T cells also showed less early recruitment and pathogenicity in the CMy-mOva myocarditis model. These results identify a prominent role for selectin ligands in contributing to effector CD8+ T cell recruitment into the myocardium and indicate that selectin-dependent T cell recruitment is relevant to other tissues besides the skin.

Adoptive Transfer↗
PubMed2006

Intensive statin therapy and the risk of hospitalization for heart failure after an acute coronary syndrome in the PROVE IT-TIMI 22 study.

OBJECTIVES: We aimed to determine whether intensive statin therapy reduces hospitalization for heart failure (HF) in high-risk patients. BACKGROUND: While the relationship between intensive statin therapy and ischemic events is well established, its relationship to the risk of HF after an acute coronary syndrome (ACS) is not well defined. METHODS: The Pravastatin or Atorvastatin Evaluation and Infection Trial-Thrombolysis In Myocardial Infarction 22 (PROVE IT-TIMI 22) study randomized 4,162 patients, stabilized after ACS, to either intensive statin therapy (atorvastatin 80 mg) or moderate statin therapy (pravastatin 40 mg). Hospitalization for HF occurring more than 30 days after randomization was determined during a mean follow-up of 24 months. B-type natriuretic peptide (BNP) levels were measured at baseline (median seven days after randomization). RESULTS: Treatment with atorvastatin 80 mg significantly reduced the rate of hospitalization for HF (2.3% vs. 3.9%, [corrected] hazard ratio [HR] 0.64, 95% confidence interval [CI] 0.45 to 0.91, p = 0.012) [corrected] independently of a recurrent myocardial infarction or prior history of HF. The risk of HF increased steadily with increasing quartiles of BNP (HR 2.45, 95% CI 1.33 to 4.52, p = 0.004 [corrected] for the highest quartile compared with the lowest). Among patients with elevated levels of BNP (>80 pg/ml), treatment with atorvastatin significantly reduced the risk of HF compared with pravastatin (HR 0.50, 95% CI 0.27 to 0.93, p = 0.028). [corrected]. A meta-analysis of four trials that included 27,546 patients demonstrates a 27% reduction in the odds of hospitalization for HF with intensive statin therapy. CONCLUSIONS: Intensive statin therapy reduces the risk of hospitalization for HF after ACS with the most gain in patients with elevated levels of BNP.

Acute Disease↗
PubMed2006

Validation of a formula that calculates the estimated risk of respiratory distress syndrome.

OBJECTIVE: Several groups, including ours, have developed probabilistic models that incorporate both the surfactant-to-albumin ratio (TDx-FLM II) and gestational age to more accurately predict the risk of neonatal respiratory distress syndrome (RDS) and eliminate the current categorical "immature"/"indeterminate"/"mature" interpretation. We validate our model using a separate data set, with the goal of providing the clinician with a risk score. METHODS: The medical records of all women who had TDx-FLM II testing performed at Brigham and Women's Hospital between January 1, 2003, and December 31, 2005, were reviewed to gather a population upon which to validate our previous logistic regression model. Receiver operating characteristic curve and Hosmer-Lemeshow analysis was conducted to determine the performance of our model and another model in this new population. RESULTS: A total of 233 mother-neonate pairs (21 RDS, 212 non-RDS) met criteria for analysis. The receiver operating characteristic analysis illustrated that our previous formula was a strong predictor of the risk of RDS with an area under the curve of 0.902 (95% confidence interval 0.849-0.955). In addition, using the Hosmer-Lemeshow analysis, our formula produced an excellent overall fit (P=.95), whereas another published model was a poor fit to our data (P=.002). CONCLUSION: Our previously derived logistic regression model formula incorporating TDx-FLM II results and gestational age to predict risk of neonatal respiratory distress syndrome was robust and stable over time in an independent data set. The results suggest that the equation can be implemented clinically to assist physicians and patients and used by other institutions after their own internal validation. LEVEL OF EVIDENCE: III.

Humans↗
PubMed2005

Prognostic value of serial B-type natriuretic peptide testing during follow-up of patients with unstable coronary artery disease.

CONTEXT: Elevated concentrations of B-type natriuretic peptide (BNP) at presentation in patients with acute coronary syndrome (ACS) are associated with long-term mortality. Few data exist regarding serial assessment of BNP levels during follow-up. OBJECTIVE: To determine whether concentrations of BNP at study entry (prior to hospital discharge for ACS) and at outpatient follow-up at 4 months and 12 months are associated with subsequent clinical outcomes. DESIGN, SETTING, AND PATIENTS: Prospective observational substudy of 4497 patients with non-ST-elevation or ST-elevation ACS who were enrolled in phase Z of the A to Z trial, which was conducted in 41 countries at 322 acute care hospitals between 1999 and 2003. MAIN OUTCOME MEASURE: Death from any cause or new onset of congestive heart failure (CHF) through 2 years. RESULTS: Levels of BNP were available in 4266 patients at study entry (prior to hospital discharge), 3618 patients at 4 months, and 2966 patients at 12 months. During follow-up there were 230 deaths and 163 incident cases of CHF. Adjusting for age, sex, index event, renal function, hypertension, prior heart failure, and diabetes, elevated levels of BNP (>80 pg/mL) were associated with subsequent death or new CHF when measured at study entry (111 [21%] vs 246 [7%]; adjusted hazard ratio [HR], 2.5; 95% confidence interval [CI], 2.0-3.3), at 4 months (34 [19%] vs 125 [4%]; adjusted HR, 3.9; 95% CI, 2.6-6.0), and at 12 months (19 [11%] vs 37 [1%]; adjusted HR, 4.7; 95% CI, 2.5-8.9). Patients with newly elevated levels of BNP at 4 months were at increased risk of death or new CHF (10 [15%] vs 105 [3%]); HR, 4.5; 95% CI, 2.3-8.6). Patients with elevated levels of BNP at study entry and with BNP levels lower than 80 pg/mL at 4 months tended to have only modestly increased risk (HR, 1.7; 95% CI, 1.0-2.9) compared with patients with BNP levels lower than 80 pg/mL at both visits. CONCLUSIONS: Serial determinations of BNP levels during outpatient follow-up after ACS predict the risk of death or new CHF. Changes in BNP levels over time are associated with long-term clinical outcomes and may provide a basis for enhanced clinical decision making in patients after onset of ACS.Clinical Trials Registration ClinicalTrials.gov Identifier: NCT00251576.

Coronary Disease↗
PubMed2005

Point-of-care (POC) versus central laboratory instrumentation for monitoring oral anticoagulation.

Point-of-care (POC) instruments employing fingerstick whole blood to monitor patients treated with warfarin are a popular alternative to complex, central laboratory coagulation analyzers utilizing citrated plasma derived from venipuncture. We investigated the accuracy of two widely utilized POC instruments for oral anticoagulation monitoring compared with a central laboratory instrument. Instrument-to-instrument variation differed for the two POC instruments, which correlated with the central laboratory instrument, but exhibited positive bias of 0.24 - 0.35 INR units. Positive bias increased as the INR values increased. We conclude that clinicians should exercise caution when interpreting results generated by POC monitors, particularly at high INR values. A high POC measurement of INR does not necessarily warrant decreasing the warfarin dose. Instead, a predefined cut-off range for high INR values generated by POC instruments should mandate confirmatory testing with central laboratory instrumentation.

Anticoagulants↗
PubMed2004

Timing and magnitude of increases in levothyroxine requirements during pregnancy in women with hypothyroidism.

BACKGROUND: Hypothyroidism during pregnancy has been associated with impaired cognitive development and increased fetal mortality. During pregnancy, maternal thyroid hormone requirements increase. Although it is known that women with hypothyroidism should increase their levothyroxine dose during pregnancy, biochemical hypothyroidism occurs in many. In this prospective study we attempted to identify precisely the timing and amount of levothyroxine adjustment required during pregnancy. METHODS: Women with hypothyroidism who were planning pregnancy were observed prospectively before and throughout their pregnancies. Thyroid function, human chorionic gonadotropin, and estradiol were measured before conception, approximately every two weeks during the first trimester, and monthly thereafter. The dose of levothyroxine was increased to maintain the thyrotropin concentration at preconception values throughout pregnancy. RESULTS: Twenty pregnancies occurred in 19 women and resulted in 17 full-term births. An increase in the levothyroxine dose was necessary during 17 pregnancies. The mean levothyroxine requirement increased 47 percent during the first half of pregnancy (median onset of increase, eight weeks of gestation) and plateaued by week 16. This increased dose was required until delivery. CONCLUSIONS: Levothyroxine requirements increase as early as the fifth week of gestation. Given the importance of maternal euthyroidism for normal fetal cognitive development, we propose that women with hypothyroidism increase their levothyroxine dose by approximately 30 percent as soon as pregnancy is confirmed. Thereafter, serum thyrotropin levels should be monitored and the levothyroxine dose adjusted accordingly.

Adult↗
PubMed2004

Characterization of a highly polymorphic marker adjacent to the SLC4A1 gene and of kidney immunostaining in a family with distal renal tubular acidosis.

BACKGROUND: Mutations in the human SLC4A1 (AE1/band 3) gene are associated with hereditary spherocytic anaemia and with distal renal tubular acidosis (dRTA). The molecular diagnosis of AE1 mutations has been complicated by the absence of highly polymorphic genetic markers, and the pathogenic mechanisms of some dRTA-associated AE1 mutations remain unclear. Here, we characterized a polymorphic dinucleotide repeat close to the human AE1 gene and performed an immunocytochemical study of kidney tissue from a patient with inherited dRTA with a defined AE1 mutation. METHODS: One CA repeat region was identified in a phage P1-derived artificial chromosome (PAC) clone containing most of the human AE1 gene and the upstream flanking region. We determined its heterozygosity value in multiple populations by PCR analysis. Genotyping of one family with dominant dRTA identified the AE1 R589H mutation, and family member genotypes were compared with the CA repeat length. AE1 and vH(+)-ATPase polypeptides in kidney tissue from an AE1 R589H patient were examined by immunocytochemistry for the first time. RESULTS: This CA repeat, previously reported as D17S1183, is approximately 90 kb upstream of the AE1 gene and displayed considerable length polymorphism, with small racial differences, and a heterozygosity value of 0.56. The allele-specific length of this repeat confirmed co-segregation of the AE1 R589H mutation with the disease phenotype in a family with dominant dRTA. Immunostaining of the kidney cortex from one affected member with superimposed chronic pyelonephritis revealed vH(+)-ATPase-positive intercalated cells in which AE1 was undetectable, and proximal tubular epithelial cells with apparently enhanced apical vH(+)-ATPase staining. CONCLUSIONS: The highly polymorphic dinucleotide repeat adjacent to the human AE1 gene may be useful for future studies of disease association and haplotype analysis. Intercalated cells persist in the end-stage kidney of a patient with familial autosomal dominant dRTA associated with the AE1 R589H mutation. The absence of detectable AE1 polypeptide in those intercalated cells supports the genetic prediction that the AE1 R589H mutation indeed causes dominant dRTA.

Acidosis, Renal Tubular↗
PubMed2004

Substitution Glu480Lys in erythroid band 3 corresponds to the Fr(a) blood group antigen and supports existence of the second ectoplasmic loop of band 3.

BACKGROUND: Polymorphisms in extracellular loops of RBC band 3 correspond to antigens of the Diego blood group system. Of the seven putative extracellular loops, no mutations have until recently been found in the second, fifth, and sixth loops. We detected a substitution Glu480Lys that would be located in its second ectoplasmic loop. We hypothesized the substitution may underlie a novel antigen of the Diego system. STUDY DESIGN AND METHODS: IAT was performed using two different multispecific sera containing anti-Fr(a) and a series of multispecific sera containing antibodies against other blood group antigens of the Diego blood group system but not agglutinating Fr(a+) RBCs. Biosynthesis of band 3 was studied by RT-PCR of reticulocyte RNA and electrophoresis of solubilized RBC membranes. Anion exchange function of band 3 was studied by measuring the influx of radiolabeled sulfate. RESULTS: RBCs from the Glu480Lys carrier were agglutinated with sera containing anti-Fr(a) and not by sera with specificities for other antigens of the Diego system. We detected identical quantities of mRNA corresponding to the two band-3 alleles and normal content of band 3 in the RBC membranes, as well as normal sulfate influx into RBCs from the Fr(a) heterozygote. CONCLUSIONS: We confirmed the previously reported molecular basis of the Fr(a) antigen, thus providing supportive evidence for the existence of the second extracellular loop of band 3. We also demonstrated that this substitution does not affect mRNA stability, surface expression, and anion exchange function of band 3.

Amino Acid Sequence↗
PubMed2003

Elevated plasma levels of the atherogenic mediator soluble CD40 ligand in diabetic patients: a novel target of thiazolidinediones.

BACKGROUND: Considerable evidence implicates the proinflammatory cytokine CD40 ligand (CD40L) in atherosclerosis and accumulating data link type 1 and 2 diabetes, conditions associated with accelerated atherosclerosis, to inflammation. This study therefore evaluated the hypothesis that diabetic patients have elevated plasma levels of soluble CD40L (sCD40L) and that treatment with the insulin-sensitizing thiazolidinediones lowers this index of inflammation. METHODS AND RESULTS: Subjects with type 1 (n=49) or type 2 diabetes (n=48) had higher (P<0.001) sCD40L plasma levels (6.56+/-3.27 and 6.67+/-2.90 ng/mL, respectively) compared with age-matched control groups (1.40+/-2.21 and 1.32+/-2.68 ng/mL, respectively). Multiple regression analysis demonstrated a significant (P<0.001) association between plasma sCD40L and type 1 as well as type 2 diabetes, independent of total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, triglycerides, blood pressure, body mass index, gender, C-reactive protein, and soluble intracellular adhesion molecule-1. Furthermore, in a pilot study, administration of troglitazone (12 weeks, 600 mg/day), but not placebo, to type 2 diabetics (n=68) significantly (P<0.001) diminished sCD40L plasma levels by 29%. The thiazolidinedione lowered plasma sCD40L in type 2 diabetic patients with long-standing disease (>3 years) with or without macrovascular complications (-34% and -29%, respectively) as well as in type 2 diabetic patients with more recent (<3 years) onset of the disease (-27%; all P<0.05). CONCLUSIONS: This study provides new evidence that individuals with type 1 or 2 diabetes have a proinflammatory state as indicated by elevated levels of plasma sCD40L. Troglitazone treatment of type 2 diabetic patients diminishes sCD40L levels, suggesting a novel antiinflammatory mechanism for limiting diabetes-associated arterial disease.

Acute Disease↗
PubMed2003

Simultaneous (AC)n microsatellite polymorphism analysis and single-stranded conformation polymorphism screening is an efficient strategy for detecting ankyrin-1 mutations in dominant hereditary spherocytosis.

Nonsense/stop mutations in the ankyrin-1 gene (ANK1) are a major cause of dominant HS (dHS) (frequency of 23% in German dHS patients). To date, no common mutation has been found and therefore a simple mutation screening is not feasible. The reduced expression of one cDNA allele in the (AC)n microsatellite polymorphism of the ankyrin-1 gene, as seen in about 20% of Czech patients with dHS, may identify candidates with a possible frameshift/nonsense mutation. In order to verify the efficiency of this screening we screened the ankyrin-1 gene of 22 Czech dHS patients for both the reduced cDNA allele expression in the frequent (AC)n and the common exonic 26/39 polymorphisms, as well as for polymerase chain reaction (PCR) single-stranded conformation polymorphisms in any one of the 42 exons of ANK1. Anomalous PCR products were sequenced. We found seven new ANK1 frameshift/nonsense mutations in nine patients with, but in none of six patients without, a reduced cDNA allele expression (efficiency of 78%). We conclude that screening of dHS patients for such a reduced allele expression in common ANK1 polymorphisms is an efficient procedure for the identification of candidates for frameshift/nonsense mutations in the ankyrin-1 gene.

Ankyrins↗
PubMed2003

The relative toxicity of amitriptyline, bupivacaine, and levobupivacaine administered as rapid infusions in rats.

UNLABELLED: Intravascular injection of local anesthetics carries the risk of cardiovascular (CV) and central nervous system (CNS) toxicity. Amitriptyline, a tricyclic antidepressant, has local anesthetic potency that is more than that of bupivacaine. In this study, we compared the CV and CNS toxicity of the local anesthetics bupivacaine and levobupivacaine with that of amitriptyline. Twenty-nine Sprague-Dawley rats had their right external jugular vein and carotid artery cannulated under general anesthesia. On Day 2, rats were sedated with midazolam (0.375 mg/kg intraperitoneally) and received rapid infusions of either 1) bupivacaine, levobupivacaine, or amitriptyline at 2 mg x kg(-1) x min(-1) (5 mg/mL concentration) or 2) normal saline (400 micro L x kg(-1) x min(-1)) through an external jugular vein cannula. Electrocardiogram and arterial blood pressure were measured until the dose to cause impending death was reached (heart rate 50 bpm/asystole or apnea for >30 s). The mean dose required to cause apnea and impending death was significantly larger for amitriptyline (74.0 +/- 21 mg/kg and 74.5 +/- 21 mg/kg, respectively) than for levobupivacaine (32.2 +/- 20 mg/kg and 33.9 +/- 22 mg/kg, respectively) or bupivacaine (21.5 +/- 7 mg/kg and 22.7 +/- 7 mg/kg, respectively) (P < 0.05). A significantly larger dose of amitriptyline, given by rapid infusion, is required to cause CV and CNS toxicity in rats, when compared with bupivacaine and levobupivacaine. IMPLICATIONS: Amitriptyline, a tricyclic antidepressant, has local anesthetic properties and is more potent than bupivacaine. Significantly larger doses of amitriptyline, given by rapid infusion, are required to cause cardiovascular and central nervous system toxicity in rats, when compared with bupivacaine and levobupivacaine.

Amitriptyline↗
PubMed2002

Modulation of Gardos channel activity by cytokines in sickle erythrocytes.

It has recently been shown that the Gardos channel activity of mouse erythrocytes can be modified by endothelins, suggesting a functional linkage between endothelin receptors and the Gardos channel. Using (86)Rubidium ((86)Rb) influx, effects were estimated of proinflammatory molecules such as platelet activator factor (PAF), endothelin-1 (ET-1), interleukin-10 (IL-10), and regulated on activation normal T cells expressed and secreted (RANTES) on the Gardos channel activity in human normal and sickle red cells. It was found that PAF (EC(50): 15 +/- 7 nM), RANTES (EC(50), 9 +/- 6 ng/mL [1.2 +/- 0.8 nM]), IL-10 (EC(50), 11 +/- 8 ng/mL [204 +/- 148 nM]), and ET-1 (EC(50), 123 +/- 34 nM) induce a significant increase in Gardos channel activity-between 28% and 84%-over the control. In addition, these agents modify the Gardos channel affinity for internal Ca(++) (K(0.5)) by 2- to 6-fold. Biochemical evidence is provided for the presence of ET receptor subtype B in sickle and normal red cells. Furthermore, it was found that ET-1, PAF, RANTES, and IL-10 induce a significant increase in red cell density (P <.05). These data suggest that activation of the Gardos channel is functionally coupled to receptor motifs such as C-X-C (PAF), C-C (RANTES), and ET receptor subtype B. Thus, cell volume regulation or erythrocyte hydration states might be altered by activation of the Gardos channel by cytokines in vivo. The role of these mediators in promoting sickle cell dehydration in vivo is under investigation.

Anemia, Sickle Cell↗
PubMedDate not supplied

Serum biomarkers for heart failure.

The incidence of heart failure has been steadily increasing over the past several decades. High readmission rates in patients with acute decompensated heart failure led to the search for biomarkers that could predict future clinical course and would, in an ideal case, enable monitoring of patients with heart failure and guidance of their therapy. From among several promising markers, the B-type natriuretic peptide and the biologically inactive N-terminal portion of its pro-hormone, NT-proBNP, have become the most frequently used analytes. Other known markers, such as atrial natriuretic peptide and endothelin-1, are currently used for research purposes. The development of additional biomarkers will be an important step from improving diagnosis and treatment of patients with chronic and acute decompensated heart failure.

Amino Acid Sequence↗
PubMedDate not supplied

Gene expression profiles of microvascular endothelial cells after stimuli implicated in the pathogenesis of vasoocclusion.

Altered gene expression in endothelial cells interacting with sickle red blood cells (RBC) and other blood components, in particular the pro-inflammatory cytokines, is an essential step in the pathogenesis of vasoocclusive crises in sickle cell disease (SCD). Using cDNA arrays, we monitored gene expression profiles of human lung microvascular endothelial cells (HMVEC-L) after stimuli that are likely involved in the pathogenesis of vasoocclusion. We detected increased expression of multiple genes in HMVEC-L after their exposure to pro-inflammatory cytokines TNFalpha and IL-1beta and to RBC with increased external exposure of phosphatidylserine and RBC from a patient with SC hemoglobin. While some of these genes have previously been implicated in vascular damage, many represent new targets for investigation of the pathogenesis of vasoocclusion in SCD.

Cells, Cultured↗