Subvalvular membrane on the left ventricular outflow tract: multidetector computerised tomography imaging.

In this report, we describe a patient with a subvalvular membrane on the left ventricular outflow tract. Discrete subvalvular membrane is a cause of left ventricular outflow tract narrowing. Multidetector computerised tomography can demonstrate the anatomical three-dimensional view of this region and guide for surgery.

Mcl-1 is a potential therapeutic target in multiple types of cancer.

Resistance to apoptosis is a common challenge in human malignancies contributing to both progress of cancer and resistance to conventional therapeutics. Abnormalities in a variety of cell intrinsic and extrinsic molecular mechanisms cooperatively promote tumor formation. Therapeutic approaches that specifically target components of these molecular mechanisms are getting widespread attention. Mcl-1 is a highly expressed pro-survival protein in human malignancies and its cellular expression is tightly regulated via multiple mechanisms. Mcl-1 differs from other members of the Bcl-2 family in having a very short half-life. So inhibition of its expression and/or neutralization of its anti-apoptotic function will rapidly make Mcl-1-dependent cells more susceptible to apoptosis and provide an opportunity to combat several types of cancers. This review summarizes the current knowledge on the regulation of Mcl-1 expression and discusses the alternative approaches targeting Mcl-1 in human cancer cells whose survivals mainly depend on Mcl-1.

Alternative splicing of Bcl-2-related genes: functional consequences and potential therapeutic applications.

Apoptosis is a morphologically distinct form of cell death. It is executed and regulated by several groups of proteins. Bcl-2 family proteins are the main regulators of the apoptotic process acting either to inhibit or promote it. More than 20 members of the family have been identified so far and most have two or more isoforms. Alternative splicing is one of the major mechanisms providing proteomic complexity and functional diversification of the Bcl-2 family proteins. Pro- and anti-apoptotic Bcl-2 family members should function in harmony for the regulation of the apoptosis machinery, and their relative levels are critical for cell fate. Any mechanism breaking down this harmony by changing the relative levels of these antagonistic proteins could contribute to many diseases, including cancer and neurodegenerative disorders. Recent studies have shown that manipulation of the alternative splicing mechanisms could provide an opportunity to restore the proper balance of these regulator proteins. This review summarises current knowledge on the alternative splicing products of Bcl-2-related genes and modulation of splicing mechanisms as a potential therapeutic approach.

Regulation of neutrophil apoptosis via death receptors.

Human neutrophils constitutively undergo apoptosis, process which is critical for the successful resolution of inflammation by the safe removal of effete cells. A wide variety of agents can modulate neutrophil apoptosis and these act through multiple and complex receptor-signalling pathways. Whilst these pathways can be initiated via distinct cell surface receptors, many downstream intracellular pathways can converge, use common molecules or trigger similar cellular activities, such as activation of caspases and transcription factors. The cell surface receptors, TNFR and Fas both trigger apoptosis in certain cell types, including neutrophils. However, TNF receptors also activate survival mechanisms in human neutrophils. This review summarises current knowledge about the regulation of neutrophil apoptosis via death receptors, the molecular components involved in signalling and potential therapeutic targets that are based on death receptors or their signalling pathways.

BCL-2 family expression in human neutrophils during delayed and accelerated apoptosis.

The human neutrophil spontaneously undergoes apoptosis, but this type of cell death can be delayed or accelerated by a wide variety of agents. There are wide discrepancies in the literature regarding the expression of the Bcl-2 family of proteins in human neutrophils. Here, we show that A1, Mcl-1, Bcl-X(L), and Bad are major transcripts in human neutrophils and that levels of these transcripts are cytokine regulated. However, no Bcl-X(L) protein was detected in Western blots. Protein levels for the proapoptotic proteins Bad, Bax, Bak, and Bik remained constant during culture, despite changes in the levels of mRNA for these gene products. These proapoptotic proteins were extremely stable, having very long half-lives. In contrast, A1 and Mcl-1 transcripts were extremely unstable (with approximately 3-h half-lives), and Mcl-1 protein was also subject to rapid turnover. These results indicate that neutrophil survival is regulated by the inducible expression of the short-lived Mcl-1 and possibly the A1 gene products. In the absence of their continued expression, these prosurvival gene products are rapidly turned over, and then the activity of the stable death proteins predominates and promotes apoptosis.

Molecular control of neutrophil apoptosis.

Human neutrophils constitutively undergo apoptosis and this process is critical for the resolution of inflammation. Whilst neutrophil apoptosis can be modulated by a wide variety of agents including GM-CSF, LPS and TNF-alpha, the molecular mechanisms underlying neutrophil death and survival remain largely undefined. Recent studies have shown the involvement of members of the Bcl-2 protein family (especially Mcl-1 and A1) and caspases in the regulation and execution of neutrophil apoptosis. Cell surface receptors and protein kinases, particularly mitogen-activated protein kinases, also play critical roles in transducing the signals that result in neutrophil apoptosis or extended survival. This review summarises current knowledge on the molecular mechanisms and components of neutrophil apoptosis.

Alterations of total and lipid-bound sialic acid levels in recurrent abortion.

OBJECTIVE: Sialic acid, a terminal component of glycoproteins and glycolipids, is found to be elevated in many pathologic conditions, including preterm deliveries and uterine dysfunction. Along with increased lipid peroxides, it is one of the indices of oxidative stress seen in recurrent abortion. This article investigates whether changes in plasma total sialic acid (TSA) and lipid-bound sialic acid (LSA) contribute to this condition. PATIENTS AND METHODS: Plasma samples of 25 nonpregnant (NP) healthy women, 25 normotensive pregnant women (NTP), and 120 women with recurrent abortion (RA) were assayed for TSA, LSA, total protein (TP), and TSA/TP. Recurrent aborters were divided into four subgroups according to etiology: 25 autoimmune (AUTO), 25 luteal phase defect (LPD), 20 anatomical defect (AD), and 50 with unexplained etiology (UNEx). RESULTS: Plasma TSA and LSA levels were significantly elevated in AUTO aborters in comparison with controls (NP and NTP) and other recurrent abortion subgroups. TSA/TP value was significantly increased in abortion with immunological and unexplained etiology (AUTO and UNEx). CONCLUSIONS: According to our results we can suggest that elevation of TSA and LSA is indeed a reflection of the immunologic abnormalities in the AUTO group, and that TSA and LSA increase is secondary to the underlying disease of AUTO aborters.

Functional analysis of the human MCL-1 gene.

We have isolated a 6.5-kb human genomic fragment that encodes the MCL-1 gene. Comparison of the coding region with the published full-length cDNA reveals that the gene contains three exons and two introns, and that our clone contains 370 bp of the 3'-untranslated region. We have mapped a major transcriptional start site to 80 residues upstream of the translation initiation codon. Reporter gene assays indicate that regulatory sequences responsible for phorbol ester (PMA)-stimulated activity and granulocyte-macrophage-colony-stimulating factor (GM-CSF)-stimulated activity were located within the first 294 bp of the 5'-flanking region upstream from the transcription start site. A deletion mutant was generated that lacked 47 bp between residues --215 and -- 168: in this mutant, six out of seven GGCCCC repeats and two GCTCA repeats were deleted. Serum-stimulated and GM-CSF-stimulated reporter activity were greatly decreased in this deletion mutant and PMA-stimulated activity was slightly decreased. While the coding and 3'-untranslated regions of the human and mouse genes have significant sequence similarity, there was very little sequence similarity in the 5'-flanking regions of the genes from these two species. Nevertheless, some consensus sequences for a number of transcription-factor-binding sites were detected in the two genes, indicating that transcription may be regulated by similar signalling pathways in these different species.

In vivo localisation and stability of human Mcl-1 using green fluorescent protein (GFP) fusion proteins.

Mcl-1 is an anti-apoptotic member of the Bcl-2 family of proteins. We have expressed full length and mutated GFP:Mcl-1 fusion proteins to define structural motifs that control protein localisation and stability. When expressed in U-937 cells, full length Mcl-1 locates primarily within mitochondria and its half-life was approximately 3 h, which was identical to the native, endogenously expressed protein. When the terminal 20 amino acids from the C-terminus of the protein were detected, the protein was diffused in the cytoplasm, but its stability was unaffected. This confirms that this region is responsible for efficient targeting to mitochondria. Surprisingly, deletion of 104 amino acids (residues 79-183) that contain putative PEST sequences and other stability regulating motifs, did not affect protein stability.

Antioxidant defence in recurrent abortion.

Increased free radical activity has been implicated in the pathogenesis of recurrent abortion. This investigation was conducted to determine if changes in some parameters of the antioxidant system contribute to this condition. Plasma ascorbic acid, alpha-tocopherol, total thiols, ceruloplasmin, uric acid, albumin, and erythrocyte glutathione (GSH) were assayed in 25 nonpregnant (NP) healthy women, 25 normotensive pregnants (NTP), and 120 women with recurrent abortion. Recurrent aborters were divided into four subgroups according to the etiology: autoimmune (AUTO, n=25), luteal phase defect (LPD, n=25), anatomical defect (AD, n=20) and unexplained (UNEx, n=50). Plasma levels of ascorbic acid, alpha-tocopherol, and erythrocyte GSH were significantly decreased in AUTO, UNEx and LPD subgroups than those in two control groups and the AD group (ANOVA). Plasma thiols of UNEx and AUTO aborters were diminished according to controls and other abortion subgroups (ANOVA). Ceruloplasmin levels showed a decline in AUTO and UNEx subgroups when compared to controls, AD and LPD aborters (ANOVA). When UNEx, AUTO and LPD recurrent abortion subgroups were compared with each other (Student's t-test) total thiols and erythrocyte GSH of UNEx and AUTO subgroups were diminished in comparison with LPD. We suggest that decreased concentrations of plasma ascorbic acid, alpha-tocopherol, total thiols and erythrocyte GSH in UNEx, AUTO and LPD reflect the increased oxidative stress, expressing a progress of the condition. Also, the imbalance between antioxidant defence and free radical activity is more evident in the AUTO subgroup. As a conclusion, although impaired antioxidant defence may be responsible for recurrent abortions, the recurrent abortions may also result in oxidative stress and depletion and weakness of antioxidant defence.

Hormone replacement therapy and urinary prostaglandins in postmenopausal women.

The objective of the study was to observe the effects of hormone replacement therapy upon urinary prostaglandin E2 and prostaglandin F2 alpha levels in postmenopausal patients. A total number of 55 women were enrolled in this study and 15 premenopausal (PreM) healthy subjects constitute the control group. A total of 40 patients at least 12 months after their natural menopause were divided into two groups: 15 of them was not medicated hormone replacement therapy (which composed NRHRT group) while 25 of the rest, received conjugated estrogen (Premarin) 0.625 mg/day orally plus medroxyprogesterone acetate (Farlutal) 10 mg/day orally built up the RHRT group. PGE2 and PGF2 alpha levels were measured with PGE2 [125I] and PGF2 alpha [3H] RIA kits. Statistical significance was analyzed by Student's t-test for impaired data. NRHRT and RHRT patients had had increased urinary PGE2 levels when compared with PreM (P < 0.001). HRT caused a significant decrease in PGE2 levels in menopausal women (P < 0.001). Urinary PGF2 alpha values of NRHRT and RHRT were significantly lower (P < 0.001) in comparison with PreM group. There was no difference in PGF2 alpha values between two postmenopausal groups. HRT given to postmenopausal patients might have a positive impact on prostaglandins and therefore on bone turnover in a series of various mechanisms.

Impact of calcitonin on urinary excretion of prostaglandins during menopause.

The aim of this study was to investigate the effects of calcitonin as an antiresorptive agent in postmenopausal osteoporosis in prostaglandin metabolism. Urinary prostaglandin E2 (PGE2) concentrations were determined by PGE2 (125I) RIA kit in a total number of 37 patients in postmenopause; 27 in study group with established osteoporosis (WEO) and 10 in another group without osteoporosis (WO). An additional group of 12 patients in the premenopausal period were selected as controls (PreM). Data were given as mean +/- SD and statistical analysis was performed by Student's t test for paired and unpaired values. A significant decrease in urinary PGE2 concentrations was observed in WEO (7.91 +/- 3.08 vs. 3.79 +/- 3.01 ng/l) (p < 0.001), WO (9.06 +/- 6.76 vs. 6.06 +/- 3.90 ng/l) (p < 0.05) and PreM (7.14 +/- 1.68 vs. 5.16 +/- 1.91 ng/l) (p < 0.01). As a conclusion, calcitonin seems to exert a negative effect on prostaglandin metabolism resulting in reduced new prostaglandin formation.

Urinary PGE2 and PGF2alpha levels and renal functions in preeclampsia.

The role of prostaglandin E2 (PGE2) and prostaglandin F2alpha (PGF2alpha) in the pathogenesis of hypertension and altered renal functions, which are the main symptoms of preeclampsia, has gained importance. Serum and urine samples of 59 women (24 preeclamptic pregnant (PEP), 20 normotensive pregnant (NTP) and 15 nonpregnant) were investigated by means of prostaglandin levels and urea, creatinine and creatinine clearance values. PEP patients, when compared with NTP patients, show a significant decrease in PGE2 and PGF2alpha levels (p < 0.01 and p < 0.05, respectively) accompanied by changes in some parameters of renal function such as serum urea, creatinine and creatinine clearance. Although disorders in prostaglandin levels may be responsible for some renal pathologic changes, renal functional and morphologic alterations may also result in abnormal prostaglandin activity.