Pacemaker Lead Perforation Mimicking Symptoms of Acute Pulmonary Embolism.

Myocardial perforation is a rare yet serious complication following cardiac pacemaker or defibrillator device procedures. In this article, the authors describe a case of right ventricular pacemaker lead perforation presenting to our hospital's medical assessment unit with a clinical presentation suggestive of an acute pulmonary embolism. Treatment dose low molecular weight heparin (LMWH) was commenced while awaiting CT scan. CT images were negative for PE however demonstrated RV lead perforation. Echocardiogram demonstrated pericardial effusion with the tip of RV lead in the pericardial free space. A rapid deterioration in the patient's haemodynamics prompted an emergency pericardial drain insertion and successful RV lead re-position in the cardiac catheter lab. The patient recovered well and was discharged with routine pacemaker clinic follow-up.

MR-Brain Causing Confusion.

An 82-year-old lady was found on the floor of her home, confused and surrounded by vomitus. She had a past medical history of type II diabetes, hypothyroidism, previous left total hip replacement, and previous hip fracture treated with right dynamic screw fixation. Prior to the current presentation she had been living alone, mobilizing independently with a walking stick and self-caring for her activities of daily living. She was last seen by her daughter on the previous day, and reported no concerning symptoms.

MR-Brain Causing Confusion.

This is a T2 weighted image (T2WI). In T2WI compartments filled with fluid appear brighter (as is the case of the CSF in the lateral ventricles). On the contrary, tissues with a high fat content appear as dark. This T2WI demonstrates layering of debris (figure 2- marked red star) in the occipital horn of the lateral ventricles. In this particular patient, the complete MRI report additionally demonstrated that the debris did not show a high T1 signal, demonstrated diffusion restriction, and a high FLAIR sequence. There was also restricting material observed in the fourth ventricle and the sylvian fissures bilaterally. There were no parenchymal changes or pathological contrast enhancements within the brain tissue. Whilst this appearance could represent blood, the appearance of the debrinous material itself was more in keeping with infective/pus material within the ventricles suggestive of ventriculitis.

Infectivity, transmission, and pathology of human-isolated H7N9 influenza virus in ferrets and pigs.

The emergence of the H7N9 influenza virus in humans in Eastern China has raised concerns that a new influenza pandemic could occur. Here, we used a ferret model to evaluate the infectivity and transmissibility of A/Shanghai/2/2013 (SH2), a human H7N9 virus isolate. This virus replicated in the upper and lower respiratory tracts of the ferrets and was shed at high titers for 6 to 7 days, with ferrets showing relatively mild clinical signs. SH2 was efficiently transmitted between ferrets via direct contact, but less efficiently by airborne exposure. Pigs were productively infected by SH2 and shed virus for 6 days but were unable to transmit the virus to naïve pigs or ferrets. Under appropriate conditions, human-to-human transmission of the H7N9 virus may be possible.

n-3 fatty acid-derived lipid mediators in the brain: new weapons against oxidative stress and inflammation.

Neuroprotectins, resolvins, and maresins are subfamilies of endogenous oxygenated metabolites derived from n-3 or ω-3 fatty acids (eicosapentaenoic and docosahexaenoic acids). These metabolites are associated with signal transduction processes involved in downregulation of oxidative stress, neuroinflammation and apoptosis. Eicosapentaenoic acid-derived E-series resolvins (RvE1 and RvE2) and docosahexaenoic acid-derived D-series resolvins (RvD1 and RvD2) and neuroprotectins have potent anti-inflammatory and proresolution, and antioxidant properties. They not only retard excessive inflammatory process, but also promote resolution by enhancing clearance of apoptotic cells and debris from inflamed brain tissue and vasculature leading to tissue homeostasis. These actions may underlie the beneficial effects of eicosapentaenoic acid and docosahexaenoic acid in normal human health, neurotraumatic and neurodegenerative diseases. Aspirin initiates resolution not only by exerting antithrombotic actions, but also triggering biosynthesis of specific and stereoselective epimers of resolvins, protectins, and maresins. In addition during the onset of resolution, these lipid mediators also display potent protective roles in neural systems, liver, lungs, and eyes. Potent anti-inflammatory actions of resolvins, and protectins in models of chronic human diseases indicate that down-regulation in resolution pathways may contribute to the decrease in the intensity of many chronic neurodegenerative and visceral diseases.

Increased expression of acyl-coenzyme A: cholesterol acyltransferase-1 and elevated cholesteryl esters in the hippocampus after excitotoxic injury.

Significant increases in levels of cholesterol and cholesterol oxidation products are detected in the hippocampus undergoing degeneration after excitotoxicity induced by the potent glutamate analog, kainate (KA), but until now, it is unclear whether the cholesterol is in the free or esterified form. The present study was carried out to examine the expression of the enzyme involved in cholesteryl ester biosynthesis, acyl-coenzyme A: cholesterol acyltransferase (ACAT) and cholesteryl esters after KA excitotoxicity. A 1000-fold greater basal mRNA level of ACAT1 than ACAT2 was detected in the normal brain. ACAT1 mRNA and protein were upregulated in the hippocampus at 1 and 2 weeks after KA injections, at a time of glial reaction. Immunohistochemistry showed ACAT1 labeling of oligodendrocytes in the white matter and axon terminals in hippocampal CA fields of normal rats, and loss of staining in neurons but increased immunoreactivity of oligodendrocytes, in areas affected by KA. Gas chromatography-mass spectrometry analyses confirmed previous observations of a marked increase in level of total cholesterol and cholesterol oxidation products, whilst nuclear magnetic resonance spectroscopy showed significant increases in cholesteryl ester species in the degenerating hippocampus. Upregulation of ACAT1 expression was detected in OLN93 oligodendrocytes after KA treatment, and increased expression was prevented by an antioxidant or free radical scavenger in vitro. This suggests that ACAT1 expression may be induced by oxidative stress. Together, our results show elevated ACAT1 expression and increased cholesteryl esters after KA excitotoxicity. Further studies are necessary to determine a possible role of ACAT1 in acute and chronic neurodegenerative diseases.

Involvement of cytosolic phospholipase A(2), calcium independent phospholipase A(2) and plasmalogen selective phospholipase A(2) in neurodegenerative and neuropsychiatric conditions.

Enzymes belonging to the PLA(2) superfamily catalyze the hydrolysis of unsaturated fatty acids from the sn-2 position of glycerol moiety of neural membrane phospholipids. The PLA(2) superfamily is classified into cytosolic PLA(2) (cPLA(2)), calcium-independent PLA(2) (iPLA(2)), plasmalogen-selective PLA(2) (PlsEtn-PLA(2)) and secretory PLA(2) (sPLA(2)). PLA(2) paralogs/splice variants/isozymes are part of a complex signal transduction network that maintains cross-talk among excitatory amino acid and dopamine receptors through the generation of second messengers. Individual paralogs, splice variants and multiple forms of PLA(2) may have unique enzymatic properties, tissue and subcellular localizations and role in various physiological and pathological situations, hence tight regulation of all PLA(2) isoforms is essential for normal brain function. Quantitative RT-PCR analyses show significantly higher relative level of expression of iPLA(2) than cPLA(2) in all regions of the rat brain. Upregulation of the cPLA(2) family is involved in degradation of neural membrane phospholipids and generation of arachidonic acid-derived lipid metabolites that have been implicated in nociception, neuroinflammation, oxidative stress and neurodegeneration. In contrast, studies using a selective iPLA(2) inhibitor, bromoenol lactone, or antisense oligonucleotide indicate that iPLA(2) is an important "housekeeping" enzyme under basal conditions, whose activity is required for the prevention of vacuous chewing movements, a rodent model for tardive dyskinesia, and deficits in the prepulse inhibition of the auditory startle reflex, a common finding in schizophrenia. These studies support the view that PLA(2) activity may not only play a crucial role in neurodegeneration but depending on the isoform, could also be essential in prevention of neuropsychiatric diseases. The findings could open new doors for understanding and treatment of neurodegenerative and neuropsychiatric diseases.

Evidence of late Palaeocene-early Eocene equatorial rain forest refugia in southern Western Ghats, India.

Equatorial rain forests that maintain a balance between speciation and extinction are hot-spots for studies of biodiversity. Western Ghats in southern India have gained attention due to high tropical biodiversity and endemism in their southern most area. We attempted to track the affinities of the pollen fl ora of the endemic plants of Western Ghat area within the fossil palynoflora of late Palaeocene-early Eocene (approximately 55-50 Ma) sedimentary deposits of western and northeastern Indian region. The study shows striking similarity of extant pollen with twenty eight most common fossil pollen taxa of the early Palaeogene. Widespread occurrences of coal and lignite deposits during early Palaeogene provide evidence of existence of well diversified rain forest community and swampy vegetation in the coastal low lying areas all along the western and northeastern margins of the Indian subcontinent. Prevalence of excessive humid climate during this period has been seen as a result of equatorial positioning of Indian subcontinent, superimposed by a long term global warming phase (PETM and EECO) during the early Palaeogene. The study presents clear evidence that highly diversifi ed equatorial rain forest vegetation once widespread in the Indian subcontinent during early Palaeogene times, are now restricted in a small area as a refugia in the southernmost part of the Western Ghat area. High precipitation and shorter periods of dry months seem to have provided suitable environment to sustain lineages of ancient tropical vegetation in this area of Western Ghats in spite of dramatic climatic changes subsequent to the post India-Asia collision and during the Quaternary and Recent times.

Informed consent in the Pakistani milieu: the physician's perspective.

Informed consent enjoys an unassailable position in both clinical and research situations as a safeguard of patients' rights. Keeping the patient involved in the decision making process is easier when there is direct communication with the individual. The Pakistani milieu offers challenges to this process because crucial decision making is often done by family members or is left entirely up to the attending physician. There seems to be a general acceptance of this shifting of focus from the individual to other players. This also raises certain ethical dilemmas for physicians who may feel uncomfortable with communication which excludes the patient or in accepting a paternalistic primary decision making role. The objective of this informal qualitative study was to ascertain physicians' perceptions regarding the process of information delivery to the patient in the Pakistani context and the various influences acting upon it.

Group IIA secretory phospholipase A2 stimulates exocytosis and neurotransmitter release in pheochromocytoma-12 cells and cultured rat hippocampal neurons.

Recent evidence shows that secretory phospholipase A2 (sPLA2) may play a role in membrane fusion and fission, and may thus affect neurotransmission. The present study therefore aimed to elucidate the effects of sPLA2 on vesicle exocytosis. External application of group IIA sPLA2 (purified crotoxin subunit B or purified human synovial sPLA2) caused an immediate increase in exocytosis and neurotransmitter release in pheochromocytoma-12 (PC12) cells, detected by carbon fiber electrodes placed near the cells, or by changes in membrane capacitance of the cells. EGTA and a specific inhibitor of sPLA2 activity, 12-epi-scalaradial, abolished the increase in neurotransmitter release, indicating that the effect of sPLA2 was dependent on calcium and sPLA2 enzymatic activity. A similar increase in neurotransmitter release was also observed in hippocampal neurons after external application of sPLA2, as detected by changes in membrane capacitance of the neurons. In contrast to external application, internal application of sPLA2 to PC12 cells and neurons produced blockade of neurotransmitter release. Our recent studies showed high levels of sPLA2 activity in the normal rat hippocampus, medulla oblongata and cerebral neocortex. The sPLA2 activity in the hippocampus was significantly increased, after kainate-induced neuronal injury. The observed effects of sPLA2 on neurotransmitter release in this study may therefore have a physiological, as well as a pathological role.

Induction of astrocytic cytoplasmic phospholipase A2 and neuronal death after intracerebroventricular carrageenan injection, and neuroprotective effects of quinacrine.

Glial reaction is often associated with nervous tissue injury, but thus far, few studies have examined whether it can be a cause of neuronal injury. We now study the effect of intracerebroventricular injection of a carrageenan on cytoplasmic phospholipase A(2) (cPLA(2)) expression and neuronal injury in the hippocampus. The enzyme cPLA(2) hydrolyzes neural membrane glycerophospholipids and generates precursors for proinflammatory mediators. An induction of cPLA(2) in astrocytes and death of neurons in the hippocampus were observed following glial reaction induced by intracerebroventricular injections of carrageenan. cPLA(2) levels and neuronal death were modulated by daily intraperitoneal injections of quinacrine, an inhibitor of phospholipase A(2) that can cross the blood brain barrier. These observations support a role for astrocytic cPLA(2) in mediating neuronal death.

Secretory phospholipase A2 activity in the normal and kainate injected rat brain, and inhibition by a peptide derived from python serum.

The present study aimed to elucidate sPLA(2) activity in the normal and kainate-lesioned hippocampus using selective inhibitors of sPLA(2). In normal rats the highest levels of sPLA(2) were observed in the hippocampus, pons, and medulla, followed by the cerebral neocortex and caudate nucleus. After intracerebroventricular kainate injections an increase in total PLA(2) activity was observed in the rat hippocampus. Using a selective sPLA(2) inhibitor 12-epi-scalaradial, sPLA(2) activity was found to be significantly increased by 2.5-fold on the side of the intracerebroventricular injection compared to the contralateral side. A peptide P-NT.II, derived from the amino acid sequence of "PLA(2)-inhibitory protein," discovered in the serum of the reticulated python, also showed potent sPLA(2) inhibitory activity in homogenates from the kainate-injected hippocampus. These results show that there is a high level of sPLA(2) activity in the normal hippocampus, pons, and medulla oblongata, and that the level increases further in the hippocampus after kainate-induced excitotoxic injury. The increased PLA(2) activity was inhibited by P-NT.II, indicating a potential use of this peptide as a PLA(2) inhibitory agent in the brain.

Clinical and laboratory features of systemic lupus erythematosus (SLE) in Pakistani patients.

OBJECTIVES: To study the clinico-pathological features of systemic lupus erythematosus (SLE) in Pakistani patients at the time of presentation in the four teaching hospitals of Rawalpindi-Islamabad area. SETTINGS: Department of Immunology, Armed Forces Institute of Pathology (AFIP), Rawalpindi, Military Hospital (MH), Rawalpindi, Armed Forces Institute of Urology (AFIU), Rawalpindi, Combined Military Hospital (CMH), Rawalpindi, Department of Rheumatology, Pakistan Institute of Medical Sciences (PIMS), Islamabad. SUBJECTS: Patients suffering from SLE, diagnosed on the basis of the ARA criteria. MAIN OUTCOME MEASURES: Clinico-pathological features at the time of presentation. RESULTS: Twelve male patients in age range 5-30 years (mean 21.6 years) and 38 female patients in age range 8-37 years (mean 22.2 years) were included in the study, showing a female to male ratio of 3:1. Fever was the most common presenting feature (100%), followed by arthralgias/arthritis (98%), malar rash (64%) and oral ulcers (58%). Laboratory results showed antinuclear antibody to be positive in all patients followed by anti double stranded DNA antibodies (anti DNA antibodies: 64%), anti extractable nuclear antigen antibodies (anti ENA antibodies: 64%) and evidence of complement consumption in 64% of the patients. Erythrocyte Sedimentation Rate (ESR) was found to be increased with a mean of 64 mm first hour fall in males and a mean of 87 mm first hour fall in the female patients. The C reactive protein was detected to be normal or marginally increased inspite of the increased ESR with mean of 7 mg/l for male patients and 5 mg/1 for the females. CONCLUSION: The subject patient population presented almost universally with fever and arthralgias or arthritis in combination with malar rash or oral ulcers and in some patients a combination of all of the above was observed. A combination of positive anti nuclear antibody test, evidence for consumption of the complement in form of low C4 and C3, increased ESR and low C reactive protein were found to be a sensitive and cost effective set of laboratory findings for the diagnosis of patients suffering from SLE. The above mentioned set of clinical and laboratory features would help in the correct and early diagnosis of patients suffering from SLE, a relatively rare disease, in the busy medical out patient departments in our set up.

Neurochemical consequences of kainate-induced toxicity in brain: involvement of arachidonic acid release and prevention of toxicity by phospholipase A(2) inhibitors.

In kainate-induced neurotoxicity, the stimulation of kainate receptors results in the activation of phospholipase A(2) and a rapid release of arachidonic acid from neural membrane glycerophospholipids. This process raises arachidonic acid levels and produces alterations in membrane fluidity and permeability. These result in calcium influx and stimulation of lipolysis and proteolysis, production of lipid peroxides, depletion of ATP, and loss of reduced glutathione. As well as the above neurochemical changes, stimulation of ornithine decarboxylase, altered activities of protein kinase C isozymes, and expression of immediate early genes, cytokines, growth factors, and heat shock proteins have also been reported. Kainate-induced stimulation of arachidonic acid release, calcium influx, accumulation of lipid peroxides and products of their decomposition, especially 4-hydroxynonenal (4-HNE), along with alterations in cellular redox state and ATP depletion may play important roles in kainate-induced cell death. Thus the consequences of altered glycerophospholipid metabolism in kainate-induced neurotoxicity can lead to cell death. Kainate-induced neurotoxicity initiates apoptotic as well as necrotic cell death depending upon the intensity of oxidative stress and abnormality in mitochondrial function. Other neurochemical changes may be related to synaptic reorganization following kainate-induced seizures and may be involved in recapitulation of hippocampal development and synaptogenesis.

Effect of D609 on phosphatidylcholine metabolism in the nuclei of LA-N-1 neuroblastoma cells: a key role for diacylglycerol.

In our previous studies, TPA treatment of LA-N-1 cells stimulated the production of diacylglycerol in nuclei, probably through the activation of a phospholipase C. Stimulation of the synthesis of nuclear phosphatidylcholine by the activation of CTP:phosphocholine cytidylyltransferase was also observed. The present data show that both effects were inhibited by the pretreatment of the cells with D609, a selective phosphatidylcholine-phospholipase C inhibitor, indicating that the diacylglycerol produced through the hydrolysis of phosphatidylcholine in the nuclei is reutilized for the synthesis of nuclear phosphatidylcholine and is required for the activation of CTP:phosphocholine cytidylyltransferase.

Plasmalogens: workhorse lipids of membranes in normal and injured neurons and glia.

Plasmalogens are unique glycerophospholipids because they have an enol ether double bond at the sn-1 position of the glycerol backbone. They are found in all mammalian tissues, with ethanolamine plasmalogens 10-fold higher than choline plasmalogens except in muscles. The enol ether double bond at the sn-1 position makes plasmalogens more susceptible to oxidative stress than the corresponding ester-bonded glycerophospholipids. Plasmalogens are not only structural membrane components and a reservoir for second messengers but may also be involved in membrane fusion, ion transport, and cholesterol efflux. Plasmalogens may also act as antioxidants, thus protecting cells from oxidative stress. Receptor-mediated degradation of plasmalogens by plasmalogen-selective phospholipase A2 results in the generation of arachidonic acid, eicosanoids, and platelet activating factor. Low levels of these metabolites have trophic effects, but at high concentration they are cytotoxic and may be involved in allergic response, inflammation, and trauma. Levels of plasmalogens are decreased in several neurological disorders including Alzheimer's disease, ischemia, and spinal cord trauma. This may be due to the stimulation of plasmalogen-selective phospholipase A2. A deficiency of plasmalogens in peroxisomal disorders and Niemann-Pick type C disease indicates that this deficiency may be due to the decreased activity of plasmalogen synthesizing enzymes that occur in peroxisomes.

Plasmalogens, phospholipase A2, and docosahexaenoic acid turnover in brain tissue.

Plasmalogens are glycerophospholipids of neural membranes containing vinyl ether bonds. Their synthetic pathway is located in peroxisomes and endoplasmic reticulum. The rate-limiting enzymes are in the peroxisomes and are induced by docosahexaenoic acid (DHA). Plasmalogens often contain arachidonic acid (AA) or DHA at the sn-2 position of the glycerol moiety. The receptor-mediated hydrolysis of plasmalogens by cytosolic plasmalogen-selective phospholipase A2 generates AA or DHA and lysoplasmalogens. AA is metabolized to eicosanoids. The mechanism of signaling with DHA is not known. The plasmalogen-selective phospholipase A2 differs from other intracellular phospholipases A2 in molecular mass, kinetic properties, substrate specificity, and response to glycosaminoglycans, gangliosides, and sialoglycoproteins. A major portion of [3H]DHA incorporated into neural membranes is found at the sn-2 position of ethanolamine glycerophospholipids. Studies with a mutant cell line defective in plasmalogen biosynthesis indicate that the incorporation of DHA is reduced in this RAW 264.7 cell line by 50%. In contrast, the incorporation of AA remains unaffected. This is reversed completely when the growth medium is supplemented with sn-1-hexadecylglycerol, suggesting that DHA can be selectively targeted for incorporation into plasmalogens. We suggest that deficiencies of DHA and plasmalogens in peroxisomal disorders, Alzheimer's disease (AD), depression, and attention deficit hyperactivity disorders (ADHD) may be responsible for abnormal signal transduction associated with learning disability, cognitive deficit, and visual dysfunction. These abnormalities in the signal-transduction process can be partially corrected by supplementation with a diet enriched with DHA.

Effect of retinoic acid on the Ca2+-independent phospholipase A2 in nuclei of LA-N-1 neuroblastoma cells.

LA-N-1 neuroblastoma cell cultures contain Ca2+-independent phospholipases A2 hydrolyzing phosphatidylethanolamine and ethanolamine plasmalogens. These enzymes differ from each other in their molecular mass, substrate specificity, and kinetic properties. Subcellular distribution studies have indicated that the activity of these phospholipases is not only localized in the cytosol but also in non-nuclear membranes and in nuclei. The treatment of LA-N-1 neuroblastoma cell cultures with retinoic acid results in a marked stimulation of Ca2+-independent phospholipases A2 hydrolyzing phosphatidylethanolamine and plasmenylethanolamine. The increase of the activities of both enzymes was first observed in nuclei followed by those present in the cytosol. No effect of retinoic acid on either phospholipase activity could be observed in non-nuclear membranes. The stimulation of these enzymes may be involved in the generation and regulation of arachidonic acid and its metabolites during differentiation.

Differential effects of calcium-dependent and calcium-independent phospholipase A(2) inhibitors on kainate-induced neuronal injury in rat hippocampal slices.

Brain tissue contains multiple forms of intracellular phospholipase A(2) (PLA(2)) activity that differ from each other in many ways including their response to specific inhibitors. The systemic administration of kainic acid to rats produces a marked increase in cPLA(2) activity in neurons and astrocytes. This is associated with increased lipid peroxidation as evidenced by accumulation of 4-hydroxynonenal (4-HNE) modified proteins. The present study describes the effect of specific inhibitors of Ca(2+)-dependent or Ca(2+)-independent PLA(2) on kainite-induced excitotoxic injury in rat hippocampal slices. Specific inhibitors of Ca(2+)-dependent PLA(2) prevented the decrease of a neuronal marker, GluR1, and increase in cPLA(2) and 4-HNE immunoreactivities in slices treated with kainate. This shows that cPLA(2) plays an important role in kainite-induced neurotoxicity and that cPLA(2) inhibitors can be used to protect hippocampal slices from damage induced by kainate.