Inhibition of myocardial reperfusion injury by ischemic postconditioning requires sirtuin 3-mediated deacetylation of cyclophilin D

RATIONALE

How ischemic postconditioning can inhibit opening of the mitochondrial permeability transition pore (PTP) and subsequent cardiac myocytes death at reperfusion remains unknown. Recent studies have suggested that de-acetylation of cyclophilin D (CyPD) by sirtuin 3 (SIRT3) can modulate its binding to the PTP.

OBJECTIVE

The aim of the present study was to examine whether ischemic postconditioning (PostC) might activate SIRT3 and consequently prevent lethal myocardial reperfusion injury through a deacetylation of CyPD.

METHODS AND RESULTS

Using hypoxia-reoxygenation (H/R) in H9C2 cells, we showed that SIRT3 overexpression prevented CyPD acetylation, limited PTP opening and reduced cell death by 24%. In vitro modification of the CyPD acetylation status in MEFs by site-directed mutagenesis altered capacity of PTP opening by calcium. Calcium Retention Capacity (CRC) was significantly decreased with CyPD-KQ that mimics acetylated protein compared with CyPD WT (871 ± 266 vs 1193 ± 263 nmoles Ca(2+)/mg protein respectively). Cells expressing non-acetylable CyPD mutant (CyPD-KR) displayed 20% decrease in cell death compared to cells expressing CyPD WT after H/R. Correspondingly, in mice we showed that cardiac ischemic postconditioning could not reduce infarct size and CyPD acetylation in SIRT3 KO mice, and was unable to restore CRC in mitochondria as it is observed in WT mice.

CONCLUSIONS

Our study suggests that the increased acetylation of CyPD following myocardial ischemia-reperfusion facilitates PTP opening and subsequent cell death. Therefore ischemic postconditioning might prevent lethal reperfusion injury through an increased SIRT3 activity and subsequent attenuation of CyPD acetylation at reperfusion.

Is malnutrition a risk factor of stroke?

Obesity is an established risk factor of stroke. Malnutrition in post-stroke period is common and can influence outcome. But malnutrition, though predicted, has not yet been established as a risk factor of stroke. This descriptive study was carried out in the Department of Neurology, Bangabandhu Sheikh Mujib Medical University (BSMMU), Dhaka and Department of Neurology, Dhaka Medical College (DMC), from January 2009 to December 2010 to explore whether malnutrition is an independent risk factor of stroke. Nutritional status of 100 stroke patients and 100 healthy controls were assessed in this study. Anthropometric measurements including Body Mass Index (BMI), Triceps skin fold (TSF), Mid-arm circumference (MAC) and Arm-muscle circumference (AMC) were measured within 7 days of stroke. Haemoglobin and haematocrit percentage, serum iron and serum albumin were measured at the same time. No significant difference was observed regarding TSF thickness, MAC, AMC, mean Hb and mean albumin level between the stroke patients and the control group, although iron level was significantly lower in stroke group. Multiple logistic regressions analysis showed that increase in age, smoking and decreased serum iron level has a positive association with stroke. Malnutrition is, according to this study, not a significant risk factor of stroke and triceps skin fold (TSF) thickness, mid-arm circumference (MAC), arm-muscle circumference (AMC), hemoglobin and serum albumin are not appropriate predictor of stroke.

Cyclophilin D and myocardial ischemia-reperfusion injury: a fresh perspective

Reperfusion is characterized by a deregulation of ion homeostasis and generation of reactive oxygen species that enhance the ischemia-related tissue damage culminating in cell death. The mitochondrial permeability transition pore (mPTP) has been established as an important mediator of ischemia-reperfusion (IR)-induced necrotic cell death. Although a handful of proteins have been proposed to contribute in mPTP induction, cyclophilin D (CypD) remains its only bona fide regulatory component. In this review we summarize existing knowledge on the involvement of CypD in mPTP formation in general and its relevance to cardiac IR injury in specific. Moreover, we provide insights of recent advancements on additional functions of CypD depending on its interaction partners and post-translational modifications. Finally we emphasize the therapeutic strategies targeting CypD in myocardial IR injury. This article is part of a Special Issue entitled "Mitochondria: From Basic Mitochondrial Biology to Cardiovascular Disease".

Effect of aeration on pollutants removal, biofilm activity and protozoan abundance in conventional and hybrid horizontal subsurface-flow constructed wetlands

The large area demand of constructed wetlands (CWs) is documented as a weak point that can be potentially reduced by applying active aeration. The aim of this study was, therefore, to understand the effects of aeration on the treatment performance, the biofilm activity, the protozoan population size and potential CW footprint reduction of different horizontal flow (HF) CW configurations. Two experimental periods were considered: a first period with low organic loading rate (OLR) and a second period with high OLR. Three HF CW configurations were compared: a conventional (control), an aerated and a hybrid CW (aerated followed by a non-aerated CW). The results obtained reinforced the competence of aerated CW for organic matter removal (81-89% of chemical oxygen demand) while for nitrogen elimination the control (19-24%) and hybrid (8-41%) systems performed better than the aerated system (-6% to 33%). Biofilm activity and protozoa abundance were distinctly higher at the inlet zones when compared with the outlet zones of all CWs, as well as in the aerated systems when compared with the non-aerated CWs. The protozoan abundance increased with an increase in the OLR and ciliates were found to be the dominant group. Overall, the active aeration highlighted the efficiency and stability of the CWs for organic matter removal and thus can be used as a promising tool to enhance microbial activity and grazing by protozoa; eventually reducing solid accumulation in the bed media. These beneficial effects contribute to reduce the CWs' area requirements.

Metabolism-secretion coupling and mitochondrial calcium activities in clonal pancreatic β-cells

Pancreatic β-cells are the only cells capable of lowering blood glucose by secreting insulin. The β-cell continuously adjusts its secretory activity to substrate availability in order to keep blood glucose levels within the physiological range--a process called metabolism-secretion coupling. Glucose is readily taken up by the β-cell and broken down into intermediates that fuel oxidative metabolism inside the mitochondria to generate ATP. The resulting increase in the ATP/ADP ratio causes closure of plasma membrane KATP channels, thereby depolarizing the cell and triggering the opening of voltage-gated Ca²⁺ channels. Consequential oscillations of cytosolic Ca²⁺ not only mediate the exocytosis of insulin granules but are also relayed to other subcellular compartments including the mitochondria, where Ca²⁺ is required to accelerate mitochondrial metabolism in response to nutrient stimulation. The mitochondrial Ca²⁺ uptake machinery plays a fundamental role in this feed-forward mechanism that guarantees sustained insulin secretion and, thus, represents a promising therapeutic target for type 2 diabetes.

Molecularly distinct routes of mitochondrial Ca2+ uptake are activated depending on the activity of the sarco/endoplasmic reticulum Ca2+ ATPase (SERCA)

The transfer of Ca²⁺ across the inner mitochondrial membrane is an important physiological process linked to the regulation of metabolism, signal transduction, and cell death. While the definite molecular composition of mitochondrial Ca²⁺ uptake sites remains unknown, several proteins of the inner mitochondrial membrane, that are likely to accomplish mitochondrial Ca²⁺ fluxes, have been described: the novel uncoupling proteins 2 and 3, the leucine zipper-EF-hand containing transmembrane protein 1 and the mitochondrial calcium uniporter. It is unclear whether these proteins contribute to one unique mitochondrial Ca²⁺ uptake pathway or establish distinct routes for mitochondrial Ca²⁺ sequestration. In this study, we show that a modulation of Ca²⁺ release from the endoplasmic reticulum by inhibition of the sarco/endoplasmatic reticulum ATPase modifies cytosolic Ca²⁺ signals and consequently switches mitochondrial Ca²⁺ uptake from an uncoupling protein 3- and mitochondrial calcium uniporter-dependent, but leucine zipper-EF-hand containing transmembrane protein 1-independent to a leucine zipper-EF-hand containing transmembrane protein 1- and mitochondrial calcium uniporter-mediated, but uncoupling protein 3-independent pathway. Thus, the activity of sarco/endoplasmatic reticulum ATPase is significant for the mode of mitochondrial Ca²⁺ sequestration and determines which mitochondrial proteins might actually accomplish the transfer of Ca²⁺ across the inner mitochondrial membrane. Moreover, our findings herein support the existence of distinct mitochondrial Ca²⁺ uptake routes that might be essential to ensure an efficient ion transfer into mitochondria despite heterogeneous cytosolic Ca²⁺ rises.

The endocannabinoid N-arachidonoyl glycine (NAGly) inhibits store-operated Ca2+ entry by preventing STIM1-Orai1 interaction

The endocannabiniod anandamide (AEA) and its derivate N-arachidonoyl glycine (NAGly) have a broad spectrum of physiological effects, which are induced by both binding to receptors and receptor-independent modulations of ion channels and transporters. The impact of AEA and NAGly on store-operated Ca(2+) entry (SOCE), a ubiquitous Ca(2+) entry pathway regulating many cellular functions, is unknown. Here we show that NAGly, but not AEA reversibly hinders SOCE in a time- and concentration-dependent manner. The inhibitory effect of NAGly on SOCE was found in the human endothelial cell line EA.hy926, the rat pancreatic β-cell line INS-1 832/13, and the rat basophilic leukemia cell line RBL-2H3. NAGly diminished SOCE independently from the mode of Ca(2+) depletion of the endoplasmic reticulum, whereas it had no effect on Ca(2+) entry through L-type voltage-gated Ca(2+) channels. Enhanced Ca(2+) entry was effectively hampered by NAGly in cells overexpressing the key molecular constituents of SOCE, stromal interacting molecule 1 (STIM1) and the pore-forming subunit of SOCE channels, Orai1. Fluorescence microscopy revealed that NAGly did not affect STIM1 oligomerization, STIM1 clustering, or the colocalization of STIM1 with Orai1, which were induced by Ca(2+) depletion of the endoplasmic reticulum. In contrast, independently from its slow depolarizing effect on mitochondria, NAGly instantly and strongly diminished the interaction of STIM1 with Orai1, indicating that NAGly inhibits SOCE primarily by uncoupling STIM1 from Orai1. In summary, our findings revealed the STIM1-Orai1-mediated SOCE machinery as a molecular target of NAGly, which might have many implications in cell physiology.

Spatiotemporal correlations between cytosolic and mitochondrial Ca(2+) signals using a novel red-shifted mitochondrial targeted cameleon

The transfer of Ca²⁺ from the cytosol into the lumen of mitochondria is a crucial process that impacts cell signaling in multiple ways. Cytosolic Ca²⁺ ([Ca²⁺]_cyto) can be excellently quantified with the ratiometric Ca²⁺ probe fura-2, while genetically encoded Förster resonance energy transfer (FRET)-based fluorescent Ca²⁺ sensors, the cameleons, are efficiently used to specifically measure Ca²⁺ within organelles. However, because of a significant overlap of the fura-2 emission with the spectra of the cyan and yellow fluorescent protein of most of the existing cameleons, the measurement of fura-2 and cameleons within one given cell is a complex task. In this study, we introduce a novel approach to simultaneously assess [Ca²⁺]_cyto and mitochondrial Ca²⁺ ([Ca²⁺]_mito) signals at the single cell level. In order to eliminate the spectral overlap we developed a novel red-shifted cameleon, D1GO-Cam, in which the green and orange fluorescent proteins were used as the FRET pair. This ratiometric Ca²⁺ probe could be successfully targeted to mitochondria and was suitable to be used simultaneously with fura-2 to correlate [Ca²⁺]_cyto and [Ca²⁺]_mito within same individual cells. Our data indicate that depending on the kinetics of [Ca²⁺]_cyto rises there is a significant lag between onset of [Ca²⁺]_cyto and [Ca²⁺]_mito signals, pointing to a certain threshold of [Ca²⁺]_cyto necessary to activate mitochondrial Ca²⁺ uptake. The temporal correlation between [Ca²⁺]_mito and [Ca²⁺]_cyto as well as the efficiency of the transfer of Ca²⁺ from the cytosol into mitochondria varies between different cell types. Moreover, slow mitochondrial Ca²⁺ extrusion and a desensitization of mitochondrial Ca²⁺ uptake cause a clear difference in patterns of mitochondrial and cytosolic Ca²⁺ oscillations of pancreatic beta-cells in response to D-glucose.

Mitochondrial Ca2+ uptake 1 (MICU1) and mitochondrial ca2+ uniporter (MCU) contribute to metabolism-secretion coupling in clonal pancreatic β-cells

In pancreatic β-cells, uptake of Ca²⁺ into mitochondria facilitates metabolism-secretion coupling by activation of various matrix enzymes, thus facilitating ATP generation by oxidative phosphorylation and, in turn, augmenting insulin release. We employed an siRNA-based approach to evaluate the individual contribution of four proteins that were recently described to be engaged in mitochondrial Ca²⁺ sequestration in clonal INS-1 832/13 pancreatic β-cells: the mitochondrial Ca²⁺ uptake 1 (MICU1), mitochondrial Ca²⁺ uniporter (MCU), uncoupling protein 2 (UCP2), and leucine zipper EF-hand-containing transmembrane protein 1 (LETM1). Using a FRET-based genetically encoded Ca²⁺ sensor targeted to mitochondria, we show that a transient knockdown of MICU1 or MCU diminished mitochondrial Ca²⁺ uptake upon both intracellular Ca²⁺ release and Ca²⁺ entry via L-type channels. In contrast, knockdown of UCP2 and LETM1 exclusively reduced mitochondrial Ca²⁺ uptake in response to either intracellular Ca²⁺ release or Ca²⁺ entry, respectively. Therefore, we further investigated the role of MICU1 and MCU in metabolism-secretion coupling. Diminution of MICU1 or MCU reduced mitochondrial Ca²⁺ uptake in response to d-glucose, whereas d-glucose-triggered cytosolic Ca²⁺ oscillations remained unaffected. Moreover, d-glucose-evoked increases in cytosolic ATP and d-glucose-stimulated insulin secretion were diminished in MICU1- or MCU-silenced cells. Our data highlight the crucial role of MICU1 and MCU in mitochondrial Ca²⁺ uptake in pancreatic β-cells and their involvement in the positive feedback required for sustained insulin secretion.

Inhibition of autophagy rescues palmitic acid-induced necroptosis of endothelial cells

Accumulation of palmitic acid (PA) in cells from nonadipose tissues is known to induce lipotoxicity resulting in cellular dysfunction and death. The exact molecular pathways of PA-induced cell death are still mysterious. Here, we show that PA triggers autophagy, which did not counteract but in contrast promoted endothelial cell death. The PA-induced cell death was predominantly necrotic as indicated by annexin V and propidium iodide (PI) staining, absence of caspase activity, low levels of DNA hypoploidy, and an early ATP depletion. In addition PA induced a strong elevation of mRNA levels of ubiquitin carboxyl-terminal hydrolase (CYLD), a known mediator of necroptosis. Moreover, siRNA-mediated knockdown of CYLD significantly antagonized PA-induced necrosis of endothelial cells. In contrast, inhibition and knockdown of receptor interacting protein kinase 1 (RIPK1) had no effect on PA-induced necrosis, indicating the induction of a CYLD-dependent but RIPK1-independent cell death pathway. PA was recognized as a strong and early inducer of autophagy. The inhibition of autophagy by both pharmacological inhibitors and genetic knockdown of the autophagy-specific genes, vacuolar protein sorting 34 (VPS34), and autophagy-related protein 7 (ATG7), could rescue the PA-induced death of endothelial cells. Moreover, the initiation of autophagy and cell death by PA was reduced in endothelial cells loaded with the Ca(2+) chelator 1,2-bis(o-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid-(acetoxymethyl) ester (BAPTA-AM), indicating that Ca(2+) triggers the fatal signaling of PA. In summary, we introduce an unexpected mechanism of lipotoxicity in endothelial cells and provide several novel strategies to counteract the lipotoxic signaling of PA.

Studying mitochondrial Ca(2+) uptake - a revisit

Mitochondrial Ca(2+) sequestration is a well-known process that is involved in various physiological and pathological mechanisms. Using isolated suspended mitochondria one unique mitochondrial Ca(2+) uniporter was considered to account ubiquitously for the transfer of Ca(2+) into these organelles. However, by applying alternative techniques for measuring mitochondrial Ca(2+) uptake evidences for molecularly distinct mitochondrial Ca(2+) carriers accumulated recently. Herein we compared different methodical approaches of studying mitochondrial Ca(2+) uptake. Patch clamp technique on mitoplasts from endothelial and HeLa cells revealed the existence of three and two mitoplast Ca(2+) currents (I(CaMito)), respectively. According to their conductance, these channels were named small (s-), intermediate (i-), large (l-) and extra-large (xl-) mitoplast Ca(2+) currents (MCC). i-MCC was found in mitoplasts of both cell types whereas s-MCC and l-MCC or xl-MCC were/was exclusively found in mitoplasts from endothelial cells or HeLa cells. The comparison of mitochondrial Ca(2+) signals, measured either indirectly by sensing extra-mitochondrial Ca(2+) or directly by recording changes of the matrix Ca(2+), showed different Ca(2+) sensitivities of the distinct mitochondrial Ca(2+) uptake routes. Subpopulations of mitochondria with different Ca(2+) uptake capacities in intact endothelial cells could be identified using Rhod-2/AM. In contrast, cells expressing mitochondrial targeted pericam or cameleon (4mtD3cpv) showed homogeneous mitochondrial Ca(2+) signals in response to cell stimulation. The comparison of different experimental approaches and protocols using isolated organelles, permeabilized and intact cells, pointed to cell-type specific and versatile pathways for mitochondrial Ca(2+) uptake. Moreover, this work highlights the necessity of the utilization of multiple technical approaches to study the complexity of mitochondrial Ca(2+) homeostasis.

The outcome of kidney transplants with multiple renal arteries

The use of grafts with multiple renal arteries has been considered a relative contraindication because of the increased incidence of vascular and urologic complications. The aim of this retrospective study is to determine whether the kidney grafts with multiple arteries have any adverse effect upon post transplant graft and patient survival. After reviewing the records of 35 adult kidney transplants done consecutively at Bangabandhu Sheik Mujib Medical University over a period of 3 years (Jan 2005 to Dec 2007). Mean age of recipients. 43.46±12.11 years and donors 40.33±11.46 years. Twenty patients (Group A) had grafts with single renal artery and 15 patients (Group B) had grafts with multiple renal arteries. The incidence of vascular complications, ureteral complications, post surgical haemorrhage, mean serum creatinine level and acute tubular necrosis in both Group A & B were observed. Complications developed in 15(43%) patients in this series. In Group A, 1(5%) developed post operative bleeding cause perinephric hematoma, 1(5%) technical obstruction of ureter, 1(5%) sloughed ureter, graft nephrectomy 1(5%) and acute tubular necrosis 1(5%) patient. In Group B, 2(13%) patients developed hematoma, urine leak 3(20%), sloughed ureter 1(6%), graft nephrectomy 1(6%) and acute tubular necrosis 3(20%) patients. Though the kidney grafts with multiple renal arteries have been considered a relative contraindication because of the increased risk of complication. In this series incidence of complication was 43%. The higher rate probably reflects the small number of living related donors.

Tuberculous pleural effusion

Despite prevention programs, tuberculosis is still endemic in developing countries. Extrapulmonary tuberculosis is increasing globally in the face of recent emergence of Human Immunodeficiency Virus (HIV) infection. Pleural tuberculosis is a common problem in daily clinical practice. We assessed 26 cases of tuberculous pleural effusion admitted in Bangabandhu Sheikh Mujib Medical University from 2002 to 2007. The diagnosis was based upon clinical examination, tuberculin reaction, imaging, pleural fluid analysis and response to antitubercular chemotherapy a surrogate clinical determinant. Apparently promising newer biochemical pleural fluid measurements were not utilized due to a number of limitations. The presenting symptoms found in this prospective analysis are fever (100%), nonproductive cough (73%), pleuritic chest pain (38%), loss of weight (38%) and shortness of breath (38%). A high index of suspicion after confident exclusion of malignancy and pneumonia is a clue to diagnosis. Out of 80 cases of extrapulmonary tuberculosis admitted during the study period, tuberculous pleural effusion constitutes 32.50%.

Intrathoracic kidney in adult with an abnormal presentation

Intra thoracic kidney is a rare congenital anomaly. Pathologically thoracic renal ectopia is due to eventration of the diaphragm. Usually symptoms appear in infancy and rarely in adult with respiratory problems and with organ involved. This only patient presented with left sided chest pain and abdominal discomfort at the age of 52 years having repeated previous similar attack in the department of Cardiology. Chest X ray and ultrasonography of whole abdomen was done along with other routine investigations, which reveals an ectopic and elevated left kidney. Five percent of the renal ectopia is intrathoracic kidney. It usually is symptomatic in infantile age but adult presentation is also found.

Factors limiting the health of semi-scavenging ducks in Bangladesh

Duck rearing is well suited to coastal and lowland areas in Bangladesh. It is an important component of sustainable livelihood strategies for poor rural communities as an additional source of household income. An epidemiological study was conducted during January 2005-June 2006 on 379 households in Chatkhil of the Noakhali District, Bangladesh which were using the recently devised "Bangladesh duck model". The overall objective of the study was to identify factors that significantly contributed to mortality and constrained productivity and to generate sufficient knowledge to enable establishment of a disease surveillance system for household ducks. The overall mortality was 15.0% in Chatkhil, with predation causing a significantly higher mortality compared with diseases (p < 0.001). Common diseases were duck plague and duck cholera. Morbid ducks frequently displayed signs associated with diseases affecting the nervous and digestive systems. Haemorrhagic lesions in various organs and white multiple foci on the liver were frequently observed in dead ducks. Epidemiological analysis with a shared frailty model that accounted for clustering of data by farm was used to estimate the association between survival time and risk factors. The overall mortality rate due to disease was significantly lower in vaccinated than in non-vaccinated ducks in all zones except zone 2 (p < 0.001). Only vaccinated ducks survived in zone 1. In conclusion, duck mortality and untimely sale of ducks appeared to be important constraints for household duck production in Chatkhil. Vaccination against duck plague appears to be an effective preventive strategy in reducing the level of associated duck mortality. A successful network was established amongst farmers and the surveillance team through which dead ducks, with accompanying information, were readily obtained for analysis. Therefore, there is an opportunity for establishing a long-term disease surveillance programme for rural ducks in Chatkhil of the Noakhali District of Bangladesh.

Extramedullary hematopoiesis and paraplegia in a patient with hemoglobin e-Beta thalassemia

Extramedullary hematopoiesis (EMH) occurs in patients with various hematologic disorders involving a chronic increase in the production of red blood cells, and is often associated polycythemia vera and sickle cell anaemia, but is less common with thalassemia especially with hemoglobin E-beta thalassemia. Spinal cord compression due to EMH is a extremely rare complication of thalassemia and may present with paraparesis or paraplegia with or without sensory impairment. Treatment options mostly include surgery and/or radiotherapy. Whereas cases presenting with paraplegia have been treated with either surgery or radiotherapy with equal frequency and efficacy, almost all reported cases with paraplegia have been treated with surgery with or without radiation therapy. We hereby report a case of hemoglobin E-beta thalassemia with paraplegia treated successfully with radiotherapy.

Lipid profile among ischemic and haemorrhagic stroke patients

This study is a prospective cross- sectional study conducted in the Neurology and Medicine department of Mymensingh Medical college Hospital (MMCH) to see the association of different components of serum lipids among ischemic and hemorrhagic stroke patients. Cases were selected following certain inclusion and exclusion criteria. Result showed that both types of stroke were more common after the age of 50 years. Male suffered more than female. M:F in ischemic stroke group was 1.73:1, and in hemorrhagic group was 1.42:1. Both types of stroke belong to middle class people. Smoking, hypertension and diabetes mellitus were equally common in both types of stroke. Low density lipoprotein (LDL) level were more than desired level in both types of stroke and there was no significant difference between two groups (p>0.05). Other components of lipid profile (total cholesterol, HDL, Triglyceride) were within normal range and there was no significant difference between two groups (p>0.05).

Frequency and distribution of patellar luxation in dogs. 134 cases (2000 to 2005)

This study investigated the frequency and distribution of patellar luxation in the dogs presented to the Chonbuk National University Animal Medical Centre during January 2000 to September 2005. Patellar luxations were classified as medial or lateral, and unilateral or bilateral, were graded I to IV, and were subdivided according to age, sex and size of the dogs. The incidence of medial patellar luxation (MPL) was greater than the incidence of lateral patellar luxation (LPL) in both small and large dogs. Small-breed dogs were admitted almost exclusively with MPL. LPL was found uncommon; however it was observed more often in larger-breed dogs. Surgical correction was performed primarily in the dogs (165 stifles in 111 dogs) with grade II, III and IV patellar luxations following different surgical techniques. The combination of the surgical techniques was found to be more effective for the management of the disease. The prognosis was found to be favourable, because when the grade was low, the dog was younger, without cruciate ligament rupture, and as the surgical correction was performed with combination of more techniques.

Placebo controlled trial of methotrexate in systemic sclerosis

Eighteen adult patients of systemic sclerosis were included in this prospective study from Rheumatology Clinic of Bangabandhu Sheikh Mujib Medical University (BSMMU), Dhaka during the period of July 1997 to December 1999 to observe the effectiveness of treatment with methotrexate (MTX) versus placebo. Among the eighteen patients 9 patients were randomly assigned to MTX and 9 to placebo therapy. Nine patients were dropped out (6 in placebo and 3 in the MTX group), because of toxicity and non-compliance. Clinical improvement following treatment was observed in 33.33% of the patient in MTX group but none in placebo group, but this difference was not statistically significant. Anorexia, nausea and occasional vomiting were common side effects in MTX group and subsided in most cases with the passage of time despite the continuation of therapy.

Solid-Phase synthesis of a library constructed of aromatic phosphate, long alkyl chains and tryptophane components, and identification of potent dipeptide telomerase inhibitors

Telomerase inhibitors are expected as a new candidate of therapeutic agents for cancer. Recently, we have found novel inhibitors based on the bisindole skeleton. In this study, solid-phase synthesis was applied to construct a library of inhibitors having aromatic phosphate, long alkyl chain and tryptophane components, from which a D,D-ditryptophane derivative has been identified as a new potent telomerase inhibitor with IC(50) values of 0.3 microM. A hypothetical binding model for the new inhibitors has been proposed based on the structure-activity relationship.

Heteroresistance to vancomycin in Enterococcus faecium

This study presents the first report of vancomycin heteroresistance in an Enterococcus faecium isolate from a patient. The original isolate was susceptible in vitro to vancomycin. E-tests showed growth of subcolonies in a zone of inhibition with a vancomycin MIC of >256 microg/ml. Both the susceptible and resistant colonies were from the same strain as determined by PFGE, and both contained the vanA gene as determined by PCR.

Signaling mediated by the cytosolic domain of peptidylglycine alpha-amidating monooxygenase

The luminal domains of membrane peptidylglycine alpha-amidating monooxygenase (PAM) are essential for peptide alpha-amidation, and the cytosolic domain (CD) is essential for trafficking. Overexpression of membrane PAM in corticotrope tumor cells reorganizes the actin cytoskeleton, shifts endogenous adrenocorticotropic hormone (ACTH) from mature granules localized at the tips of processes to the TGN region, and blocks regulated secretion. PAM-CD interactor proteins include a protein kinase that phosphorylates PAM (P-CIP2) and Kalirin, a Rho family GDP/GTP exchange factor. We engineered a PAM protein unable to interact with either P-CIP2 or Kalirin (PAM-1/K919R), along with PAM proteins able to interact with Kalirin but not with P-CIP2. AtT-20 cells expressing PAM-1/K919R produce fully active membrane enzyme but still exhibit regulated secretion, with ACTH-containing granules localized to process tips. Immunoelectron microscopy demonstrates accumulation of PAM and ACTH in tubular structures at the trans side of the Golgi in AtT-20 cells expressing PAM-1 but not in AtT-20 cells expressing PAM-1/K919R. The ability of PAM to interact with P-CIP2 is critical to its ability to block exit from the Golgi and affect regulated secretion. Consistent with this, mutation of its P-CIP2 phosphorylation site alters the ability of PAM to affect regulated secretion.