Novel mutations in the lamin A/C gene in heart transplant recipients with end stage dilated cardiomyopathy.
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Adult↗
Biomedical subjects
M Kaartinen
Publications and source records attributed to M Kaartinen.
Electrocardiographic assessment of left ventricular hypertrophy with time-voltage QRS and QRST-wave areas.
The sum of time-voltage QRS areas in the 12-lead electrocardiogram (ECG) has outperformed other 12-lead ECG indices for detection of left ventricular hypertrophy (LVH). We assessed indices of time-voltage QRS and T-wave (QRST) areas from body surface potential mapping (BSPM) for detection of and quantitation of the degree of LVH. We studied 42 patients with echocardiographic LVH (LVH group) and 11 healthy controls (controls). QRST area sums were calculated from 123-lead BSPM and from the 12-lead ECG for comparison. Leadwise discriminant indices and correlation coefficients were used to identify optimal recording locations for QRST area-based LVH assessment. BSPM QRS area sum was greater in the LVH group than in controls (3752 +/- 1259 vs 2278 +/- 627 microV s, respectively; P<0.001) and at 91% specificity showed 74% sensitivity for LVH detection. The 12-lead QRS area sum performed similarly. Taking T-wave areas into account did not improve the results. QRS area sum from two most informative leads (located in the upper and lower right precordium) also separated the LVH group from controls (61.1 +/- 23.5 vs 27.8 +/- 6.5 microV s, respectively; P<0.00001). This 2-lead QRS area sum showed 90% sensitivity with 100% specificity for LVH detection and maintained high correlation to indexed left ventricular mass (r=0.732; P<0.001). In conclusion, the BSPM QRS area sum compared to 12-lead QRS area sum does not substantially improve LVH assessment. The 2-lead QRS area sum may improve ECG QRS area-based LVH assessment.
Body Surface Potential Mapping↗
Flow cytometric analysis of apoptotic subpopulations with a combination of annexin V-FITC, propidium iodide, and SYTO 17.
BACKGROUND: We have previously characterized apoptotic cell death induced in a follicular lymphoma cell line, HF-1, after triggering via the B-cell receptor (BCR) or treatment with Ca(2+) Ionophore A23187. We analyzed the kinetics of apoptosis induced by these two treatments, as two alternative models of classical apoptosis, by flow cytometry using a novel combination of cytofluorometric stains. METHODS: Cells were stained with a combination of Annexin V-FITC, propidium iodide (PI), and SYTO 17 and analyzed by a two-laser flow cytometry system using 488-nm argon and 633-nm HeNe air-cooled lasers. RESULTS: In both apoptotic models, the first apoptotic cells were detected by SYTO 17 staining. The alteration in SYTO 17 staining intensity was followed by an increased uptake of PI. Finally, the apoptotic cells were labeled with Annexin V in BCR-induced apoptosis. On the contrary, on treatment with Ca(2+) Ionophore A23187, cells became positive for Annexin V earlier than for PI. CONCLUSIONS: The novel cytofluorometric dye, SYTO 17, discriminates apoptotic alterations before Annexin V and PI. PI also discriminates apoptotic alterations before the loss of plasma membrane asymmetry by BCR but not by Ca(2+) Ionophore A23187-induced apoptosis. Finally, the combination of these three cytofluorometric dyes allows effective detection of apoptotic subpopulations and ordering of apoptotic events by flow cytometry.
Annexin A5↗
[Gene errors of dilated cardiomyopathy].
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Cardiomyopathy, Dilated↗
Expression of angiotensin II and interleukin 6 in human coronary atherosclerotic plaques: potential implications for inflammation and plaque instability.
BACKGROUND: Patients with an activated renin-angiotensin system (RAS) or genetic alterations of the RAS are at increased risk of myocardial infarction (MI). Administration of ACE inhibitors reduces the risk of MI, and acute coronary syndromes are associated with increased interleukin 6 (IL-6) serum levels. Accordingly, the present study evaluated the expression of angiotensin II (Ang II) in human coronary atherosclerotic plaques and its influence on IL-6 expression in patients with coronary artery disease. METHODS AND RESULTS: Immunohistochemical colocalization of Ang II, ACE, Ang II type 1 (AT(1)) receptor, and IL-6 was examined in coronary arteries from patients with ischemic or dilated cardiomyopathy undergoing heart transplantation (n=12), in atherectomy samples from patients with unstable angina (culprit lesion; n=8), and in ruptured coronary arteries from patients who died of MI (n=13). Synthesis and release of IL-6 was investigated in smooth muscle cells and macrophages after Ang II stimulation. Colocalization of ACE, Ang II, AT(1) receptor, and IL-6 with CD68-positive macrophages was observed at the shoulder region of coronary atherosclerotic plaques and in atherectomy tissue of patients with unstable angina. Ang II was identified in close proximity to the presumed rupture site of human coronary arteries in acute MI. Ang II induced synthesis and release of IL-6 shortly after stimulation in vitro in macrophages and rat smooth muscle cells. CONCLUSIONS: Ang II, AT(1) receptor, and ACE are expressed at strategic sites of human atherosclerotic coronary arteries, suggesting that Ang II is produced primarily by ACE within coronary plaques. The observation that Ang II induces IL-6 and their colocalization with the AT(1) receptor and ACE is consistent with the notion that the RAS may contribute to inflammatory processes within the vascular wall and to the development of acute coronary syndromes.
Angina, Unstable↗
Permanent pacing-aid to carry out long-term lithium therapy in manic patient with symptomatic bradycardia.
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Adrenergic beta-Antagonists↗
Association between myocardial infarction and the mast cells in the adventitia of the infarct-related coronary artery.
BACKGROUND: Histamine, a product of mast cells, is an effective vasoconstrictor of atherosclerotic coronary arteries. Because it has been suggested that coronary spasm plays a role in acute coronary syndromes such as myocardial infarction (MI), we quantified and characterized the mast cells in the adventitia of infarct-related coronary arteries. METHODS AND RESULTS: In a series of 17 autopsied MI patients, we identified the segment of the left coronary artery with ruptured plaque responsible for the infarction. More distal segments from the infarct-related coronary artery, either with nonruptured plaques or with normal intima, were also studied. Corresponding segments taken from left coronary arteries obtained from 17 patients who had died of noncardiac causes served as controls. Adventitial mast cells in the infarct-related and the control coronary arteries were identified immunohistochemically by staining for tryptase. In the infarct-related coronary arteries, we also stained for chymase and histamine. Moreover, T lymphocytes and macrophages were identified immunohistochemically and counted. In the infarct-related coronary arteries, significantly larger numbers of mast cells were present in the adventitia backing ruptured plaques (98+/-40 mast cells/mm2, mean+/-SD) than in the adventitia backing nonruptured plaques (41+/-12 mast cells/mm2; P<0.001) or backing normal intima (19+/-8 mast cells/mm2; P<0.001). No such difference was found among the 3 different segments in the control coronary arteries. The majority of mast cells contained not only tryptase but also chymase. Mast cells were the only cells in the coronary adventitia that contained histamine. The proportion of adventitial mast cells that were degranulated was highest in the segments with ruptured plaques. The numbers of adventitial macrophages and T lymphocytes were also increased in the segments with plaque rupture. CONCLUSIONS: In infarct-related coronary arteries, the number of degranulated mast cells in the adventitia backing ruptured plaques is increased. Histamine released from the degranulated mast cells may reach the media, where it may locally provoke coronary spasm and thus contribute to the onset of MI.
Aged↗
A cloned human germ cell tumor-derived cell line differentiating in culture.
We have derived a clonal cell line (HGCT-1) from a lymph node metastasis of a primary testicular germ cell tumor (GCT). The tumor was negative for the embryonal carcinoma (EC) cell marker BerH2 but positive for vimentin, cytokeratin (CK) and desmin. Comparative genomic hybridization (CGH) revealed a high-level amplification at 12p that was observed in both the metastatic tumor and in the cultured HGCT-1 cells. In vitro, the phenotype of HGCT-1 cells was modulated by the culture conditions. In the presence of 10% fetal calf serum (FCS), the majority of HGCT-1 cells lacked CK and desmin. If cultured in 0.5% FCS, HGCT-1 cells acquired a uniform co-expression of vimentin, CK and desmin. Upon treatment with retinoic acid (RA), HGCT-1 cells lost the expression of desmin, but exhibited abundant CK filaments. Simultaneously, they started to express desmoplakin, form desmosomes and flatten on the culture substratum. The RA-induced changes were irreversible, whereas those following the culture in 0.5% FCS were at least partially reversible. When xenografted into an immunosuppressed rat, HGCT-1 cells formed a tumor consisting of epithelial- and mesenchymal-like structures. HGCT-1 cells thus represent a pluripotential cell system with a capacity for reversible phenotypic modulation and for irreversible differentiation into epithelial-type cells. The behavior of this novel cell line, distinct from established EC cell models, suggests a complex regulation of GCT cell differentiation.
Animals↗
Mast cell infiltration in acute coronary syndromes: implications for plaque rupture.
OBJECTIVES: To define the role of mast cells in plaque destabilization. BACKGROUND: Inflammation is an essential feature of human coronary plaques. Macrophages and T lymphocytes are considered to contribute to destabilization of the plaques. The role of mast cells in this setting is less well studied. We therefore counted the mast cells in coronary atherectomy specimens from patients with chronic stable angina, unstable angina and severe unstable angina. METHODS: Patients studied had chronic stable angina (group 1, n=11), "stabilized" unstable angina (group 2; Braunwald's class I and II, n=11) and "refractory" unstable angina (group 3; Braunwald's class III, n=7). Samples of culprit lesions (n=29) were obtained by directional atherectomy, snap-frozen and analyzed immunohistochemically. The numbers of mast cells and T lymphocytes per square millimeter squared were counted and the areas containing macrophages and smooth muscle cells were measured by computed planimetry. RESULTS: We found that the numbers of mast cells and T lymphocytes increased from group 1 through groups 2 to 3. Specimens from group 3 also contained the largest numbers of tumor necrosis factor alpha (TNF-alpha)-positive mast cells and of matrix metalloproteinase (MMP)-9 (92 kD gelatinase)-positive macrophages. CONCLUSIONS: Unstable coronary syndromes are associated with increased numbers of mast cells in culprit lesions. Activated mast cells secrete neutral proteases capable of degrading the extracellular matrix and TNF-alpha, capable of stimulating macrophages to synthesize MMP-9. Our observations suggest that mast cells, in addition to macrophages, contribute to matrix degradation and, hence, to progression of coronary syndromes.
Adult↗
p72syk protein tyrosine kinase: an early transducer of sIgG-triggered apoptotic signalling in human follicular lymphoma cells.
Cross-linking of B cell antigen receptor (sIg) elicits different biological responses, including cell activation, proliferation, differentiation, anergy and cell death depending on the maturational stage of the cell. We established the tumor cell lines HF-1.3.4 and HF-4-9 from two patients with follicular lymphoma. Both cell lines carry the characteristic t(14;18) chromosomal translocation and display constitutively overexpressed Bcl-2. HF-1.3.4 represents a mature B cell with sIgG and several somatic hypermutations in its Ig genes, while HF-4-9 is a less mature B cell, expressing sIgM and only a few mutations in its Ig genes. Cross-linking of sIg with antibodies leads to apoptosis in HF-1.3.4 cells but not in HF-4-9 cells. Triggering of sIg induced, within seconds, identical tyrosine phosphorylation of p53/56lyn protein tyrosine kinase (PTK) and p55blk PTK in both of the cell lines; however, a prominent tyrosine phosphorylation and activation of p72syk PTK only in HF-1.3.4 cells. We conclude that p72syk PTK is of importance in relaying apoptotic signalling upon sIg cross-linking in the HF-1.3.4 cell line. Given the mature phenotype of the HF-1.3.4 cell line it serves as a model for the late negative selection during B cell ontogeny. Moreover, our results question the current concept that a constitutive overexpression of BcI-2 confers resistance to sIg ligation-induced apoptosis in lymphoma cells.
Apoptosis↗
Helicobacter salomonis sp. nov., a canine gastric Helicobacter sp. related to Helicobacter felis and Helicobacter bizzozeronii.
During a study of the prevalence and distribution of gastric helicobacters in domestic pets, a novel group of Helicobacter-like organisms were identified. These "Helicobacter group 2" strains were initially distinguished from the species Helicobacter felis and Helicobacter bizzozeronii by their cellular morphology and the type of motility exhibited. Bacterial cells were only slightly spiral, 5 to 7 microns long, and 0.8 to 1.2 microns wide and showed an unusual slow wavelike motion. Each cell had tufts of sheathed flagella at one or both ends. Phylogenetic analysis by 16S ribosomal DNA sequence comparison revealed that H. felis, H. bizzozeronii, "Gastrospirillum hominis" 2, and the new group of helicobacters formed a distinct cluster with intraspecies similarity values of more than 98%. These taxa were clearly separated from all other known Helicobacter species. Dot blot DNA-DNA hybridization studies indicated that the Helicobacter group 2 strains are genetically homogeneous and distinct from other canine and feline gastric helicobacters. Quantitative DNA-DNA hybridization experiments showed that Helicobacter group 2 strains exhibit > 90% DNA homology to each other, but < 39% homology to the phylogenetically related taxa H. felis and H. bizzozeronii. We propose the name Helicobacter salomonis for the novel Helicobacter group 2 strains. The type strain is H. salomonis Inkinen (= CCUG 37845).
Animals↗
Mast cells in rupture-prone areas of human coronary atheromas produce and store TNF-alpha.
BACKGROUND: Mast cells, a cell type involved in inflammatory reactions, are present in coronary atheromas and localize to the erosion or rupture site of atheromas in myocardial infarction. Here we report the presence of TNF-alpha, a proinflammatory cytokine, in mast cells of human coronary atheromas. METHODS AND RESULTS: From samples of 37 coronary arteries from subjects autopsied for medicolegal reasons, sections of the bifurcation area of the left coronary artery were stained immunohistochemically for mast cells and TNF-alpha. In addition, macrophages, T lymphocytes, smooth muscle cells, and endothelial cells were investigated for their content of TNF-alpha. In normal intimas and fatty streaks, none of the cell types studied were TNF-alpha-positive. In 14 of the 24 atheromas found, TNF-alpha-positive cells were present. Of the total number of mast cells, 23% stained for TNF-alpha; of the macrophages, 1.3%; and of the smooth muscle cells, 0.4%. The majority (55%) of TNF-alpha-positive mast cells in the atheromas were located in the shoulder region and the remaining 35% in the cap and 10% in the core regions. Immunoelectron microscopy showed that the TNF-alpha in mast cells resided within their cytoplasmic secretory granules, demonstrating that these cells contain stores of TNF-alpha that will be released on degranulation. CONCLUSIONS: This study demonstrates the presence of mast cells with TNF-alpha-containing secretory granules, particularly in the shoulder region of human coronary atheromas. By releasing their TNF-alpha, mast cells may play an active role in the inflammatory reactions of these rupture-prone areas of atheromas.
Adult↗
Mast cells accompany microvessels in human coronary atheromas: implications for intimal neovascularization and hemorrhage.
Mast cells have been assigned a role in neovascularization. Therefore, we examined the deep regions of human coronary atheromas, the areas known to be prone to neovascularization, for the presence of mast cells. Specimens of atherosclerotic human coronary intima from 37 autopsy cases with ages of 24-84 years were stained with elastica-van Gieson to detect atheroma formation and with monoclonal antibody against von Willebrand factor to detect neovascularization. Mast cells were detected by staining the atheromas with monoclonal antibodies against the two major proteases of mast cells, tryptase and chymase. Of the 24 coronary atheromas found, 13 contained mast cells in the deep regions. All these 13 deep regions also displayed neovascularization, and the number of microvessels and the number of mast cells around the microvessels correlated strongly with the size of the atheroma. On the other hand, of the 11 deep regions lacking mast cells, only one displayed neovascularization. In the neovascularized areas of the coronary atheromas, the mast cells were in close proximity to the microvessels. All the mast cells contained tryptase, and some of them chymase, both known for their angiogenic and matrix-degrading potential. In light microscopic studies, degranulated mast cells were observed indicating activation of these cells, with release of tryptase and chymase. The selective localization of activated mast cells containing angiogenic factors around newly formed microvessels in human coronary atheromas suggests that mast cells play a role in the neovascularization of these lesions. Moreover, mast cells may also, by virtue of their neutral proteases, injure the microvessels, and thereby produce intraplaque hemorrhages and, ultimately, unstable lesions.
Adult↗
Distribution and nucleotide biases of the somatic hypermutations in the functional kappa light chain gene of a human follicular lymphoma line.
The immunoglobulin kappa chain gene of human lymphoma cell line HF-1.3.4 was partially sequenced from the 3' end of the leader exon 2.0 kb downstream. The sequenced stretch of DNA included 1.5 kb of the non-coding JK region 3' to the JK2 element of the mature gene. Among the known VK germline genes the closet relative was KV328, which was 91% homologous to HF-1.3.4. In the 1.5 kb JK region homology with JK allele of Whitehurst et al. (allele 2) was 89%, with the allele of Hieter et al. (allele 1) 87%. The vast majority of the differences located in the leader intron, the VJ exon or 0.6 kb 3' to the exon, a localization characteristic of somatic hypermutations of immunoglobulin genes. Another indication that most of the differences observed were due to somatic hypermutations is that the 153 bp stretch of the kappa constant gene (CK) sequenced from the mRNA was 100% homologous with the published CK sequence. The most differences between the JK region sequence and that of Whitehurst et al. probably represent somatic mutations: 43% were transversions, 55% transitions and 2% deletions. In the non-coding JK region transversions of C.G to G.C rather than to A.T were heavily over-represented. This is possibly a feature of B-cell hypermutations in humans and mice.
Amino Acid Sequence↗
Infiltrates of activated mast cells at the site of coronary atheromatous erosion or rupture in myocardial infarction.
BACKGROUND: Erosion and rupture of coronary atheromas are the events preceding the vast majority of acute coronary syndromes. The shoulder regions of atheromas, the sites at which erosion or rupture is most likely to occur, are the sites at which mast cells accumulate. These cells are filled with neutral proteases capable of triggering extracellular matrix degradation via activation of matrix metalloproteinases. To obtain more direct evidence for the participation of mast cells in the acute coronary syndromes, we quantified the numbers of mast cells at eroded or ruptured sites of coronary atheromas in patients who died of myocardial infarction. METHODS AND RESULTS: In specimens of coronary arteries from 20 patients who had died of acute myocardial infarction, the site of atheromatous erosion or rupture was identified. The specimens were stained with monoclonal antibodies against the two major proteases of mast cells, tryptase and chymase, and against macrophages, T lymphocytes, and smooth muscle cells. At the immediate site of erosion or rupture, mast cells amounted to 6% of all nucleated cells, in the adjacent atheromatous area to 1%, and in the unaffected intimal area to 0.1%. The proportions of these mast cells that were activated, ie, had been stimulated to degranulate and release some of their tryptase and chymase contents, were 86% at the site of erosion or rupture, 63% in the adjacent atheromatous area, and 27% in the unaffected intima. At the site of erosion or rupture, the numbers of macrophages and T lymphocytes were also increased, but the number of smooth muscle cells was decreased. CONCLUSIONS: The accumulation of activated mast cells (200-fold more than in the unaffected coronary intima) at the site of atheromatous erosion or rupture suggests that in thrombotic coronary occlusion the role played by mast cells is significant.
Cell Count↗
A human follicular lymphoma B cell line hypermutates its functional immunoglobulin genes in vitro.
The functional immunoglobulin (Ig) genes of B lymphocytes undergo somatic mutations during immune responses. These mutations modify the antigen binding site of the immunoglobulins, thereby enhancing the average affinity of the antibodies produced. The molecular mechanism underlying these B cell hypermutations remains unresolved, partly because it is difficult to grow normal B cells in long-term cell cultures and because there is no suitable transformed or malignant B cell line which generates mutations in its immunoglobulin genes in vitro. Here, we show that the recently established follicular lymphoma line HF-1.3.4 generates somatic hypermutations in vitro at a high frequency of 0.7 x 10(-6) mutations per base pair per generation in standard cell cultures (RPMI 1640 + 5% fetal calf serum). This shows for the first time that B cell hypermutation can occur without T cells or T cell factors. The mutation frequency increased approximately tenfold to 1 x 10(-5) mutations/base pair/generation with B cell-specific growth factors (interleukins-2 and -4 and three antibodies stimulatory to HF-1.3.4 cells). This HF-1.3.4 lymphoma line may help to elucidate the molecular mechanism of Ig gene hypermutation.
Amino Acid Sequence↗
The somatic hypermutation activity of a follicular lymphoma links to large insertions and deletions of immunoglobulin genes.
A biopsy specimen from a patient with follicular lymphoma was divided into two fragments. DNA was extracted from one fragment and a 1.2 kb region of the functional heavy chain (IgH) gene was amplified, cloned and sequenced (eight clones). From the other fragment a cell line (HF-1) was started. The IgH gene region was amplified from the cell line, and sequenced without cloning. The nine sequences obtained could be arranged into a genealogical tree where the individual sequences differed from the deduced ancestor by 16-29 single nucleotide changes, some also by an insertion and/or a deletion. It is apparent that the sequence alterations were caused by somatic mutations during the growth of the lymphoma. The comparison of the sequences with two published (allelic) germline sequences of the human JH region showed approximately 20% non-homology. The differences included five additional multinucleotide insertion/deletion changes, the longest of them a 101-nucleotide insertion. Two long insertions were homologous to the adjacent germline sequences. We propose that most of the changes observed, including long deletions and insertions, represent or are linked to somatic hypermutation events of the Ig gene type. Although in a few cases large deletions and insertions (> 2 bp) have been found in mutated immunoglobulin genes, our results, for the first time, firmly link these deletions/insertions to somatic hypermutations; their frequency was found to be 2.2% of the observed mutational events in the non-translated gene regions. HF-1 is the first follicular lymphoma line successfully established from a lymphoma known to have hypermutated its Ig genes during the malignant growth. It is a candidate cell line to be studied for its ability to generate mutations of B cell type in cell cultures.
Base Sequence↗
Extracellular mast cell granules carry apolipoprotein B-100-containing lipoproteins into phagocytes in human arterial intima. Functional coupling of exocytosis and phagodytosis in neighboring cells.
In experimental studies in vitro, mast cells have induced uptake of apolipoprotein B-100 (apoB-100)-containing low-density lipoproteins by macrophages, with the subsequent formation of foam cells, the hallmarks of atherosclerosis. Recently, increased numbers of activated, ie, degranulated, mast cells were found to be present in human coronary fatty streaks and atheromas. We therefore sought evidence of a connection between mast cells and foam cell formation in vivo. In electron microscopic studies of human aortic and coronary fatty streaks and atheromas, exocytosed cytoplasmic secretory granules of mast cells were detected in the vicinity of their parent cells. These exocytosed granules had bound apoB-100-containing lipoproteins, as indicated by their positive staining with MB 47, a monoclonal antibody against apoB-100. A smooth muscle cell was observed to be in the process of phagocytosing one such exocytosed granule, and in the vicinity of a degranulated mast cell a foam cell contained an ingested mast cell granule. Therefore, the micrographs show that exocytosed granules of intimal mast cells may contribute to intimal foam cell formation and suggest a role for mast cells in human atherogenesis. More generally, the findings provide evidence that phagocytosis of apoB-100-carrying particles is one mechanism by which lipoproteins enter human arterial intimal cells.
Adult↗