Oral lichenoid reaction to imatinib (STI 571, Gleevec)

Imatinib or STI 571 is a phenylaminopyrimidine derivative and a member of a new class of drugs known as signal transduction inhibitors. These compounds specifically inhibit the proliferation of v-abl- and bcr-abl-expressing cells and have recently been approved as treatment for chronic myeloid leukaemia (CML). Results have been promising, and imatinib may well be the best single agent for the treatment of CML in the near future. Here we report an erosive oral lichenoid eruption confined to the buccal mucosa and dorsum of the tongue which appeared 12 weeks after commencement of imatinib in a 72-year-old woman with CML. The histology was consistent with a lichenoid drug eruption. The lesions resolved upon withdrawal of the drug. To our knowledge, this is the first reported lichenoid reaction to imatinib, and in the setting of CML it must be differentiated from idiopathic lichen planus, paraneoplastic pemphigus and graft-versus-host disease.

Anti-septicaemic effect of polysaccharide from Panax ginseng by macrophage activation

The aim of the present research was conducted to elucidate anti-septicaemic effect of a polysaccharide (PS) isolated from Panax ginseng C.A. Meyer (Araliaceae) by nitric oxide production from stimulated macrophage. In vitro assays for the activity measurement of PS, NO production test with Greiss reagent, phagocytic activity test using zymosan and cytokines production test using ELISA kit were also conducted. In vivo anti-septicaemic activity was assessed by using C57BL/6J mice. This was done with Staphylococcus aureus infection test. PS used at 0.025 mg/kg concentration showed a potent anti-septicaemic activity (80%, survival). However, it did not directly inhibit S. aureus in a minimum inhibitory concentration (MIC) test, conducted in vitro (data not shown). Nitric oxide production via macrophage activation showed the highest value of 5.5 nmol/ml at 1 microg/ml PS. In in vitro phagocytic activity test, PS at 10 microg/ml concentration showed a potent phagocytic activity for zymosan with 167% of the control. Production of TNF-alpha by macrophage activation at 10 microg/ml of PS was 96% lysis of L929. Also production of IL-1 and IL-6 by stimulation of macrophage with 100 microg/ml PS dose increased to 235 pg/ml and 0.47 ng/ml, respectively. The low mortality of PS treated (0.025 mg/kg) infected mice was concurrent with decreased bacterial content in the blood. Nitric oxide production in S. aureus infected mice whose macrophage was stimulated by PS (0.025 mg/kg) increased approximately 4 times than the untreated S. aureus infected group at 24 and 48 h incubation. In the PS treated (0.025 mg/kg) group, the intracellular concentration of S. aureus in macrophages decreased approximately by 50%, compared with the untreated group. Combine treatment with PS (0.025 mg/kg body weight) and vancomycin (10 mg/kg B.W.) resulted in 100% survival of the animals, whereas only 67% or 50% of the animals survived, respectively, when treated with PS or vancomycin alone. These results suggest that PS from Panax ginseng possess a potent anti-septicaemic activity by stimulating macrophage and a potentiality as an immunomodulator against sepsis occurred by Staphylococcus aureus.

Grb2 dominantly associates with dynamin II in human hepatocellular carcinoma HepG2 cells

The two SH3 domains and one SH2 domain containing adaptor protein Grb2 is an essential element of the Ras signaling pathway in multiple systems. The SH2 domain of Grb2 recognizes and interacts with phosphotyrosine residues on activated tyrosine kinases, whereas the SH3 domains bind to several proline-rich domain-containing proteins such as Sos1. To define the difference in Grb2-associated proteins in hepatocarcinoma cells, we performed coprecipitation analysis using recombinant GST-Grb2 fusion proteins and found that several protein components (p170, p125, p100, and p80) differently associated with GST-Grb2 proteins in human Chang liver and hepatocarcinoma HepG2 cells. Sos1 and p80 proteins dominantly bind to Grb2 fusion proteins in Chang liver, whereas p100 remarkably associate with Grb2 in HepG2 cells. Also GST-Grb2 SH2 proteins exclusively bound to the p46(Shc), p52(Shc), and p66(Shc) are important adaptors of the Ras pathway in HepG2 cells. The p100 protein has been identified as dynamin II. We observed that the N-SH3 and C-SH3 domains of Grb2 fusion proteins coprecipitated with dynamin II besides Sos1. These results suggest that dynamin II may be a functional molecule involved in Grb2-mediated signaling pathway on Ras activation for tumor progression and differentiation of hepatocarcinoma cells.

ATM--a key determinant of multiple cellular responses to irradiation

Ataxia-telangiectasia is a rare clinical disorder manifesting a variety of different abnormalities, including progressive neurodegeneration, increased cancer incidence, immune deficiency, sterility, and extreme radiosensitivity. Recent studies have demonstrated that the defective gene product in this disease, ATM, is a protein kinase. The identification of several different substrates for this kinase is beginning to explain the wide array of different physiologic abnormalities that occur when this gene product is dysfunctional. Since the ATM protein is a critical signaling molecule in the cellular response to ionizing irradiation, the identification of these substrates also results in elucidation of the steps involved in a number of different cellular signaling pathways initiated by irradiation. Such insights also result in the identification of potential new targets for enhancing the efficacy of radiation therapy.

Expression profiling of cardiac genes in human hypertrophic cardiomyopathy: insight into the pathogenesis of phenotypes

OBJECTIVES

The goal of this study was to identify genes upregulated in the heart in human patients with hypertrophic cardiomyopathy (HCM).

BACKGROUND

Hypertrophic cardiomyopathy is a genetic disease caused by mutations in contractile sarcomeric proteins. The molecular basis of diverse clinical and pathologic phenotypes in HCM remains unknown.

METHODS

We performed polymerase chain reaction-select complementary DNA subtraction between normal hearts and hearts with HCM and screened subtracted libraries by Southern blotting. We sequenced the differentially expressed clones and performed Northern blotting to detect increased expression levels.

RESULTS

We screened 288 independent clones, and 76 clones had less than twofold increase in the signal intensity and were considered upregulated. Sequence analysis identified 36 genes including those encoding the markers of pressure overload-induced ("secondary") cardiac hypertrophy, cytoskeletal proteins, protein synthesis, redox system, ion channels and those with unknown function. Northern blotting confirmed increased expression of skeletal muscle alpha-actin (ACTA1), myosin light chain 2a (MLC2a), GTP-binding protein Gs-alpha subunit (GNAS1), NADH ubiquinone oxidoreductase (NDUFB10), voltage-dependent anion channel 1 (VDAC1), four-and-a-half LIM domain protein 1 (FHL1) (also known as SLIM1), sarcosin (SARCOSIN) and heat shock 70kD protein 8 (HSPA8) by less than twofold. Expression levels of ACTA1, MLC2a and GNAS1 were increased in six additional and FHL1 in four additional hearts with HCM.

CONCLUSIONS

A diverse array of genes is upregulated in the heart in human patients with HCM, which could account for the diversity of clinical and pathologic phenotypes. Markers of secondary hypertrophy are also upregulated, suggesting commonality of pathways involved in HCM and the acquired forms of cardiac hypertrophy. Elucidation of the role of differentially expressed genes in HCM could provide for new therapeutic targets.

Angiotensin II blockade reverses myocardial fibrosis in a transgenic mouse model of human hypertrophic cardiomyopathy

BACKGROUND

-Hypertrophic cardiomyopathy (HCM), the most common cause of sudden cardiac death in the young, is characterized by cardiac hypertrophy, myocyte disarray, and interstitial fibrosis. We propose that hypertrophy and fibrosis are secondary to the activation of trophic and mitotic factors and, thus, potentially reversible. We determined whether the blockade of angiotensin II, a known cardiotrophic factor, could reverse or attenuate interstitial fibrosis in a transgenic mouse model of human HCM.

METHODS AND RESULTS

We randomized 24 adult cardiac troponin T (cTnT-Q(92)) mice, which exhibit myocyte disarray and interstitial fibrosis, to treatment with losartan or placebo and included 12 nontransgenic mice as controls. The mean dose of losartan and the mean duration of therapy were 14.2+/-5.3 mg. kg(-1). d(-1) and 42+/-9.6 days, respectively. Mean age, number of males and females, and heart/body weight ratio were similar in the groups. Collagen volume fraction and extent of myocyte disarray were increased in the cTnT-Q(92) mice (placebo group) compared with nontransgenic mice (9.9+/-6.8% versus 4.5+/-2.2%, P=0.01, and 27.6+/-10.6% versus 3.9+/-2.3%, P<0.001, respectively). Treatment with losartan reduced collagen volume fraction by 49% to 4.9+/-2.9%. The expression of collagen 1alpha (I) and transforming growth factor-beta1, a mediator of angiotensin II profibrotic effect, were also reduced by 50%. Losartan had no effect on myocyte disarray.

CONCLUSIONS

Treatment with losartan reversed interstitial fibrosis and the expression of collagen 1alpha (I) and transforming growth factor-beta1 in the hearts of cTnT-Q(92) mice. These findings suggest that losartan has the potential to reverse or attenuate interstitial fibrosis, a major predictor of sudden cardiac death, in human patients with HCM.

Variants of trophic factors and expression of cardiac hypertrophy in patients with hypertrophic cardiomyopathy

Patients with hypertrophic cardiomyopathy (HCM) exhibit variable expression of left ventricular hypertrophy (LVH), a major determinant of mortality and morbidity, which is partly due to the diversity of causal mutations, genetic background (modifier genes), and probably environmental factors. We determined association of functional variants of tumor necrosis factor (TNF)- alpha, interleukin-6 (IL6), insulin-like growth factor-2 (IGF2), transforming growth factor- beta 1 (TGFB1), and aldosterone synthase (CYP11B2) genes, all previously implicated in cardiac hypertrophy, with the severity of LVH in patients with HCM. Two-dimensional echocardiography was performed and demographic variables were recorded in 142 genetically independent patients. Indices of LVH including interventricular septal thickness (IVST), left ventricular mass index (LVMI), and LVH score were measured/calculated. TNF-alpha-308G/A, IL6-174G/C, IGF2 820G/A, TGFB1-509C/T, and CYP11B2-344T/C genotypes were determined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Genotypes were identified by the presence of specific electrophoretic patterns and their distributions were according to the Hardy-Weinberg equilibrium. Demographic variables were not significantly different among the genotypes. Subjects with the AA genotype of TNF-alpha (n=8) were approximately 13 years younger at the time of clinical diagnosis. Despite a younger age, they had a greater mean LVMI than those with the GG (n=94) or GA (n=33) genotypes (191.8+/-59.5 v 139.1+/-47.3 v 132.1+/-34.3, respectively, P=0.004). TNF-alpha-308G/A genotypes accounted for 6.0% of variability of LVMI (P=0.002). Mean IVST, LVEDD, and LVH score were not significantly different. Variants of IL6, IGF2, TGFB1, and CYP11B2 were not associated with indices of LVH. The uncommon allele of TNF-alpha-308G/A polymorphism, known to produce more TNF- alpha, was associated with greater LVMI and clinical diagnosis at a younger age in patients with HCM. Functional variants of other trophic factors, previously implicated in cardiac hypertrophy, were not associated with the indices of LVH. These results suggest that TNF-alpha is a modifier gene for HCM.

The many substrates and functions of ATM

As its name suggests, the ATM--'ataxia-telangiectasia, mutated'--gene is responsible for the rare disorder ataxia-telangiectasia. Patients show various abnormalities, mainly in their responses to DNA damage, but also in other cellular processes. Although it is hard to understand how a single gene product is involved in so many physiological processes, a clear picture is starting to emerge.

Coronary flow reserve is reflective of myocardial perfusion status in acute anterior myocardial infarction

Our objective was to determine whether coronary vasodilatory reserve (CVR) correlates with the perfusion state of infarct zone in early recovery phase of acute anterior myocardial infarction (AMI). We studied 14 patients (11 males; mean age, 46 years) who had AMI and 6 control subjects who had chest pain but normal coronary angiograms. All patients underwent successful percutaneous revascularization of left anterior descending (LAD) coronary artery. Coronary flow velocity was measured using intracoronary (IC) Doppler at baseline and following IC injection of 18 microg of adenosine. Myocardial perfusion was evaluated by myocardial contrast echocardiography (MCE). CVR was higher in patients without a perfusion defect on MCE than in those with (2.48 +/- 0.21 vs. 1.66 +/- 0.13, P = 0.001). Subjects with a perfusion defect had a lower CVR than controls (1.66 +/- 0.13 vs.2.40 +/- 0.18, P < 0.05). CVR was > 2.0 in all subjects without a perfusion defect. There was a strong correlation between the magnitude of myocardial opacification in the LAD territory and CVR (r = 0.80, P < 0.01). Increase in peak diastolic flow velocity after adenosine infusion, but not systolic flow velocity, correlated with myocardial opacification index (r = 0.63, P = 0.016). CVR of infarct-related artery correlated closely with the perfusion status of the myocardium in infarct zone and those with a CVR > 2.0 had normal myocardial perfusion. These data suggest that CVR may be used to determine the perfusion state of the myocardium in the infarct zone, which is a known predictor of myocardial viability. Cathet. Cardiovasc. Intervent. 51:281-286, 2000.

Enhancement of adenoviral transduction with polycationic liposomes in vivo

Although the high transfection efficiency with adenovirus in vitro is well documented, it is still not clear whether adenoviral vectors are effective in vivo in solid tumor models. In our preliminary experiment, transduction of tumor tissue was limited to just around the injection site after intratumoral injection of the adenoviral vector. To improve the transduction efficiency in vivo, we tried a combination of adenoviral vector and liposome in our animal model. Adenovirus carrying human placental alkaline phosphatase (AdALP) and Lipofectamine or 1,3-di-oleoyloxy-2-(6-carboxyspermyl)-propylamide were used as a marker gene and the cationic liposome, respectively. A >15-fold increase in the transfection efficiency was observed in CT26 tumor cell lines with the combination of AdALP adenovirus carrying murine granulocyte-macrophage colony-stimulating factor (AdmGM-CSF), and liposome compared with adenovirus alone, showing the feasibility of the combination treatment. In the animal model, with the combination of liposome and AdALP, deeper and wider distribution of the marker gene in the tumor mass was shown. We conclude that the limitations of direct application of adenoviral vectors in a solid tumor model could be overcome by the use of cationic liposomes. This approach will facilitate the more effective delivery of adenoviral vectors in a clinical trial setting.

Tissue Doppler imaging consistently detects myocardial contraction and relaxation abnormalities, irrespective of cardiac hypertrophy, in a transgenic rabbit model of human hypertrophic cardiomyopathy

BACKGROUND

Hypertrophic cardiomyopathy (HCM) is diagnosed clinically by the presence of left ventricular hypertrophy (LVH). However, LVH is absent in a significant number of genotype-positive patients. Because myocyte dysfunction and disarray are the primary abnormalities in HCM, we reasoned that tissue Doppler imaging could identify contraction and relaxation abnormalities, irrespective of hypertrophy, in a transgenic rabbit model of human HCM.

METHODS AND RESULTS

M-mode, 2D, Doppler echocardiography and tissue Doppler imaging were performed in nontransgenic (n=24), wild-type beta-myosin heavy chain-arginine(403) (n=14), and mutant beta-myosin heavy chain-glutamic acid(403) (n=24) transgenic rabbits. Mean septal thicknesses were 2.0+/-0.3, 2.0+/-0.25, and 2.75+/-0.3 mm in the 3 groups, respectively (P:=0.001). LVH was absent in 9 of the 24 mutant rabbits. Left ventricular dimensions, systolic function, heart rate, mitral inflow velocities, and time intervals were similar in the groups. However, the difference between atrial reversal and transmitral A wave duration was increased in the mutant rabbits (P:<0.001). More importantly, systolic and early diastolic tissue Doppler velocities were significantly lower in all mutant rabbits (7.45+/-2.2 versus 10.8+/-2.3 cm/s in nontransgenic and 9. 0+/-0.76 cm/s in wild-type; P:<0.001), including the 9 without LVH. A systolic velocity <8.5 cm/s had an 86% sensitivity and 100% specificity in identifying the mutant transgenic rabbits.

CONCLUSIONS

Myocardial contraction and relaxation were reduced in the mutant beta-myosin heavy chain-glutamic acid(403) transgenic rabbit model of human HCM, irrespective of the presence or absence of LVH. In addition, tissue Doppler imaging is more sensitive than conventional echocardiography for HCM screening.

Analysis of ku80-mutant mice and cells with deficient levels of p53

Absence of Ku80 results in increased sensitivity to ionizing radiation, defective lymphocyte development, early onset of an age-related phenotype, and premature replicative senescence. Here we investigate the role of p53 on the phenotype of ku80-mutant mice and cells. Reducing levels of p53 increased the cancer incidence for ku80(-/-) mice. About 20% of ku80(-/-) p53(+/-) mice developed a broad spectrum of cancer by 40 weeks and all ku80(-/-) p53(-/-) mice developed pro-B-cell lymphoma by 16 weeks. Reducing levels of p53 rescued populations of ku80(-/-) cells from replicative senescence by enabling spontaneous immortalization. The double-mutant cells are impaired for the G(1)/S checkpoint due to the p53 mutation and are hypersensitive to gamma-radiation and reactive oxygen species due to the Ku80 mutation. These data show that replicative senescence is caused by a p53-dependent cell cycle response to damaged DNA in ku80(-/-) cells and that p53 is essential for preventing very early onset of pro-B-cell lymphoma in ku80(-/-) mice.

Anti-leukaemic and anti-mutagenic effects of di(2-ethylhexyl)phthalate isolated from Aloe vera Linne

Extracts of Aloe vera Linne have been found to exhibit cytotoxicity against human tumour cell lines. This study examines the anti-tumour effects of di(2-ethylhexyl)phthalate (DEHP) isolated from Aloe vera Linne, in human and animal cell lines. Its anti-mutagenic effects were examined using Salmonella typhimurium TA98 and TA100 strains. Growth inhibition was specifically exerted by DEHP against three leukaemic cell lines at concentrations below 100 microg mL(-1). At 100 microg mL(-1) DEHP, K562, HL60 and U937 leukaemic cell lines showed growth inhibition of 95, 97 and 95%, respectively. DEHP exhibited an inhibitory activity of 74, 83 and 81%, respectively, in K562, HL60 and U937 cell lines at a concentration of 10 microg mL(-1). At a concentration of 1 microg mL(-1), DEHP exerted an inhibitory activity of 50, 51 and 52%, respectively, in K562, HL60 and U937. In a normal cell line, MDBK, DEHP exerted 30% growth inhibition at a concentration of 100 microg mL(-1), and showed no inhibitory activity at concentrations below 50 microg mL(-1). It was found that DEHP exerted anti-mutagenic activity in the Salmonella mutation assay. The number of mutant colonies of Salmonella typhimurium strain TA98 upon exposure to AF-2 (0.2 microg/plate) decreased in a concentration-dependent manner in the presence of different DEHP concentrations (decreasing to 90.4, 83.9, 75.4, 69.6 and 46.9%, respectively, for DEHP concentrations of 100, 50, 10, 5 and 1 microg/plate). In the case of Salmonella typhimurium strain TA100, DEHP reduced AF-2-induced mutagenicity at 1, 5, 10, 50 and 100 microg/plate to 57.4, 77.5, 80.0, 89.0 and 91.5%, respectively. The isolated compound from Aloe vera Linne, DEHP, was considered to be the active principle responsible for anti-leukaemic and anti-mutagenic effects in-vitro.

ATM phosphorylates p95/nbs1 in an S-phase checkpoint pathway

The rare diseases ataxia-telangiectasia (AT), caused by mutations in the ATM gene, and Nijmegen breakage syndrome (NBS), with mutations in the p95/nbs1 gene, share a variety of phenotypic abnormalities such as chromosomal instability, radiation sensitivity and defects in cell-cycle checkpoints in response to ionizing radiation. The ATM gene encodes a protein kinase that is activated by ionizing radiation or radiomimetic drugs, whereas p95/nbs1 is part of a protein complex that is involved in responses to DNA double-strand breaks. Here, because of the similarities between AT and NBS, we evaluated the functional interactions between ATM and p95/nbs1. Activation of the ATM kinase by ionizing radiation and induction of ATM-dependent responses in NBS cells indicated that p95/nbs1 may not be required for signalling to ATM after ionizing radiation. However, p95/nbs1 was phosphorylated on serine 343 in an ATM-dependent manner in vitro and in vivo after ionizing radiation. A p95/nbs1 construct mutated at the ATM phosphorylation site abrogated an S-phase checkpoint induced by ionizing radiation in normal cells and failed to compensate for this functional deficiency in NBS cells. These observations link ATM and p95/nbs1 in a common signalling pathway and provide an explanation for phenotypic similarities in these two diseases.

Assessment of coronary flow reserve with transthoracic Doppler echocardiography: comparison with intracoronary Doppler method

To evaluate the feasibility and usefulness of transthoracic Doppler echocardiography (TTDE) as a non-invasive method in recording distal anterior descending (LAD) coronary flow velocity, we compared coronary flow reserve (CFR) measured by TTDE with measurements by intracoronary Doppler wire (ICDW). Twenty-one patients without LAD stenosis were studied. ICDW performed at baseline and after intracoronary injection of 18 microg adenosine. TTDE was performed at baseline and after intravenous adenosine (140 microg/kgmin for 2 min). Adequate Doppler recordings of coronary flow velocities during systole were obtained in 14 of 21 study patients (67%) and during diastole in 17 (81%) patients. Baseline and hyperemic peak diastolic flow velocities measured by TTDE were significantly smaller than those obtained by ICDW (p<0.05). However, diminishing trends of diastolic and systolic velocity ratio after hyperemia were similarly observed in both methods. CFR obtained by TTDE (3.0+/-0.5), was higher than the value calculated by ICDW (2.5+/-0.4). There were significant correlations between the values obtained by the two methods (r=0.72, p<0.01). It is concluded that TTDE is a feasible method in measuring coronary flow velocity and appears to be a promising non-invasive method in evaluating CFR.

Ionizing radiation activates the ATM kinase throughout the cell cycle

The ATM protein kinase is a critical intermediate in a number of cellular responses to ionizing irradiation (IR) and possibly other stresses. ATM dysfunction results in abnormal checkpoint responses in multiple phases of the cell cycle, including G1, S and G2. Though downstream targets of the ATM kinase are still being elucidated, it has been demonstrated that ATM acts upstream of p53 in a signal transduction pathway initiated by IR and can phosphorylate p53 at serine 15. The cell cycle stage-specificity of ATM activation and p53Ser15 phosphorylation was investigated in normal lymphoblastoid cell line (GM536). Ionizing radiation was found to enhance the kinase activity of ATM in all phases of the cell cycle. This enhanced activity was apparent immediately after treatment of cells with IR, but was not accompanied by a change in the abundance of the ATM protein. Since IR activates the ATM kinase in all phases of the cell cycle, DNA replication-dependent strand breaks are not required for this activation. Further, since p53 protein is not directly required for IR-induced S and G2-phase checkpoints, the ATM kinase likely has different functional targets in different phases of the cell cycle. These observations indicate that the ATM kinase is necessary primarily for the immediate response to DNA damage incurred in all phases of the cell cycle.

A variant of p22(phox), involved in generation of reactive oxygen species in the vessel wall, is associated with progression of coronary atherosclerosis

A series of pro-oxidant and antioxidant enzymes, such as the NADPH oxidase system, maintain the redox state in the vessel wall. A major component of NADPH oxidase is p22(phox), which is implicated in atherosclerosis. We prospectively studied the association of the histidine (H)(72)-->tyrosine (Y) mutation in p22(phox) with the severity and progression/regression of coronary artery disease (CAD), plasma lipid levels, clinical events, and response to treatment with fluvastatin in a well-characterized population. Genotypes were determined by polymerase chain reaction and restriction digestion with RsaI enzyme in 368 subjects in the Lipoprotein and Coronary Atherosclerosis Study (LCAS). Fasting plasma lipids and quantitative coronary angiograms were obtained at baseline and 2.5 years after randomization to fluvastatin or placebo. Subjects with CC genotype (n=157) were identified by the presence of 396-bp and 113-bp products on gel electrophoresis. Those with TT (n=39) were identified by the presence of 316-bp, 113-bp, and 80-bp products, and those with CT (n=172) by the presence of 396-bp, 316-bp, 113-bp, and 80-bp products. Baseline and final plasma levels of lipids and the baseline severity of CAD were not significantly different among the genotypes. In the placebo group, subjects with the mutation had a 3- to 5-fold greater loss in mean minimum lumen diameter (MLD) (TT: -0.15+/-0.15; CT: -0.17+/-0.26; and CC: -0.03+/-0.22 mm; P=0. 006) and lesion-specific MLD (TT: -0.15+/-0.06; CT: -0.18+/-0.03; and CC: -0.06+/-0.03 mm; P=0.038) than those without. Progression was also more (TT: 8/17 [47%]; CT: 35/73 [48%]; and CC: 17/62 [27%]) and regression less (TT: 0/17 [0%]; CT: 1/73 [1%]; and CC: 11/72 [18%]) common in those with the mutation (P=0.002). The C(242)T mutation in p22(phox), involved in maintaining the redox state in the vessel wall, is associated with progression of coronary atherosclerosis in the LCAS population.

Decreased left ventricular ejection fraction in transgenic mice expressing mutant cardiac troponin T-Q(92), responsible for human hypertrophic cardiomyopathy

The causality of mutant sarcomeric proteins in hypertrophic cardiomyopathy (HCM) is well established. The current emphasis is to elucidate the pathogenesis of HCM in transgenic animal models. We determined the left ventricular ejection fraction (LVEF) in transgenic mice expressing mutant cardiac troponin T (cTnT)-Q(92), known to cause HCM in humans. Transgenes were constructed by placing wild-type (R(92)) or mutant (Q(92)) full-length human cTnT cDNAs 3' into a 5.5-kb murine [alpha -myosin heavy chain (MyHC)] promoter injected into fertilized zygotes. Three wild-type and six mutant lines were produced. Transgene mRNA and proteins, detected using transgene-specific probes were expressed at high levels in all wild-type and three mutant lines. The total cTnT mRNA pool was increased by up to five-fold in transgenic mice, but the total cTnT protein remained unchanged. The mean values of LVEF, determined by(178)Ta radionuclide angiography, were 57.8+/-6% (n=4) in non-transgenic littermate (NLM), 53.3+/-10 (n=6) in wild-type and 39. 4+/-6 (n=5) in mutant transgenic mice (P=0.009). The heart/body weight ratios and the number of cells stained with terminal deoxynucleotidyl transferase (TdT)-mediated nick end-labeling were similar among the groups. Three mutant mice had myocyte disarray and excess interstitial collagen and two had normal myocardial structure despite having reduced LVEF. Thus, in vivo expression of the mutant cTnT-Q(92)protein, responsible for human HCM, impaired global cardiac systolic function in transgenic mice, which also occurred in the absence of myocyte disarray and increased interstitial collagen.