Continuous synthesis of Zn2Al–CO3layered double hydroxides: a comparison of bench, pilot and industrial scale syntheses

Zn₂Al–CO₃was produced continuously at bench (g h⁻¹), pilot (100s g h⁻¹) and industrial scale (10s kg h⁻¹).

Phylogenomic history of enigmatic pygmy perches: implications for biogeography, taxonomy and conservation

Pygmy perches (Percichthyidae) are a group of poorly dispersing freshwater fishes that have a puzzling biogeographic disjunction across southern Australia. Current understanding of pygmy perch phylogenetic relationships suggests past east-west migrations across a vast expanse of now arid habitat in central southern Australia, a region lacking contemporary rivers. Pygmy perches also represent a threatened group with confusing taxonomy and potentially cryptic species diversity. Here, we present the first study of the evolutionary history of pygmy perches based on genome-wide information. Data from 13 991 ddRAD loci and a concatenated sequence of 1 075 734 bp were generated for all currently described and potentially cryptic species. Phylogenetic relationships, biogeographic history and cryptic diversification were inferred using a framework that combines phylogenomics, species delimitation and estimation of divergence times. The genome-wide phylogeny clarified the biogeographic history of pygmy perches, demonstrating multiple east-west events of divergence within the group across the Australian continent. These results also resolved discordance between nuclear and mitochondrial data from a previous study. In addition, we propose three cryptic species within a southwestern species complex. The finding of potentially new species demonstrates that pygmy perches may be even more susceptible to ecological and demographic threats than previously thought. Our results have substantial implications for improving conservation legislation of pygmy perch lineages, especially in southwestern Western Australia.

Introducing holmium laser enucleation of the prostate alongside transurethral resection of the prostate improves outcomes of each procedure

INTRODUCTION

Holmium laser enucleation of the prostate (HoLEP) is recognised as an alternative to transurethral resection of the prostate (TURP). HoLEP has been demonstrated to be at least as effective as TURP with less morbidity but its introduction to practice has been limited in part by the learning curve of a novel procedure. This study examined the effects of introducing HoLEP alongside an established practice of TURP on early morbidity and length of hospital stay (LOS).

METHODS

A retrospective review of all patients who underwent HoLEP and TURP between April 2007 and July 2011 was undertaken. HoLEP was introduced in April 2008; patients undergoing TURP before this were considered as a historical control group. Data were collected concerning resection/enucleation weight, blood transfusions and LOS.

RESULTS

Overall, 772 patients underwent HoLEP or TURP within the 52-month study period: 164 underwent TURP prior to the introduction of HoLEP (TURP-A), 425 had TURP after the introduction of HoLEP (TURP-B) and 183 underwent HoLEP. The mean removed weight was 24g (standard deviation [SD]: 21g) for TURP-A, 19g for TURP-B (SD: 16g) and 38g (SD: 32g) for HoLEP (p<0.005). Blood transfusion rates were 5.5%, 2.2% and 1.6% for the TURP-A, TURP-B and HoLEP groups respectively (p<0.05). For TURP-A patients, the mean LOS was 5.6 days (SD: 3.5 days, 95% confidence interval [CI]: 5.3-6.0 days). The mean LOS for TURP-B patients was 4.4 days (SD: 4.4 days, 95% CI: 4.2-4.8 days). HoLEP patients had a mean LOS of 3.0 days (SD: 3.0 days, 95% CI: 2.6-3.4 days).

CONCLUSIONS

The introduction of HoLEP alongside TURP is associated with lower rates of blood transfusion and shorter LOS for all patients. This is likely to be due to the use of HoLEP rather than TURP in patients with larger prostates, who are more likely to have complications.

Intracellular sequestration of amiodarone: role of vacuolar ATPase and macroautophagic transition of the resulting vacuolar cytopathology

BACKGROUND AND PURPOSE

Tissue deposits of the anti-arrhythmic drug amiodarone are a major source of side effects (skin discoloration, etc.). We addressed the mechanism of the concentration of amiodarone in cells, and characterized the resulting vacuolar cytopathology and its evolution towards macroautophagy.

EXPERIMENTAL APPROACH

Sequestration of amiodarone in human cells (macrophages, smooth muscle cells, HEK 293a cells) was evaluated using its violet fluorescence and cytopathology using GFP-conjugated subcellular markers. Autophagic signalling was probed by immunoblotting for the effector protein LC3. A patient biopsy of amiodarone-induced blue-gray skin discoloration was investigated for the presence of macroautophagy (immunofluorescence for LC3).

KEY RESULTS

Most of the amiodarone (1-20 microM, 4-24 h) captured by cultured cells (macrophages were most avid) was present in enlarged vacuoles. The specific vacuolar ATPase (V-ATPase) inhibitors, bafilomycin A1 or FR167356, prevented vacuolization and drug uptake. Vacuoles in HEK 293a cells were positive for markers of late endosomes and lysosomes (GFP-Rab7, -CD63) and for an effector of macroautophagy, GFP-LC3. The vacuoles accumulated endogenous LC3 and filled with lipids (Nile red staining) following longer amiodarone treatments (> or =24 h). The electrophoretic mobility of both GFP-LC3 and endogenous LC3 changed, showing activation in response to amiodarone. Paraffin tissue sections of the pigmented skin exhibited granular LC3 accumulation in superficial dermis macrophages.

CONCLUSION AND IMPLICATIONS

Vacuolar sequestration of amiodarone occurs at concentrations close to therapeutic levels, is mediated by V-ATPase and evolves towards persistent macroautophagy and phospholipidosis. This cytopathology is not cell type specific, but tissue macrophages appear to be particularly susceptible.

Influence of human immunodeficiency virus type 1 envelope glycoprotein YXXL endocytosis/polarization signal on viral accessory protein functions

INTRODUCTION

A tyrosine-based targeting signal in the intracytoplasmic domain of human immunodeficiency virus type 1 (HIV-1) envelope glycoprotein is required for basolateral targeting of viral budding in polarized epithelial cells, concentration of viral assembly at one pole of infected lymphocytes, and rapid endocytosis of the glycoprotein from the plasma membrane. In HIV-1, the process of viral assembly and budding is complex and involves the participation of viral accessory proteins.

STUDY DESIGN/METHODS

In this study, we examined whether the functions of the Nef, Vif, and Vpu proteins can influence or be influenced by the presence of envelope targeting signal in epithelial cells or lymphocytes. A series of proviral DNAs combining a mutation that inactivates the targeting signal with independent mutations in the three accessory proteins was constructed for this purpose.

RESULTS

It was found that none of these three accessory proteins affected the basolateral release of the virus in polarized MDCK cells. Reciprocally, a mutation abolishing targeting of the viral envelope glycoprotein did not affect the phenotype conferred by the accessory proteins. Interestingly, the mutation abolishing targeting increased viral infectivity only in the presence of the Vpu protein. This phenotype was found to be associated with the release-enhancing function of Vpu and with an increased incorporation of viral envelope glycoprotein in virions.

CONCLUSIONS

These data clearly show that accessory protein functions, and more specifically Vpu modulation of viral infectivity, can be affected by variations in the viral envelope glycoprotein.

Ethanol-glycine irrigating fluid for transurethral resection of the prostate in practice

OBJECTIVE

To evaluate the usefulness of a tracer of 1% ethanol in 1. 5% glycine in the early detection of irrigation fluid absorption during transurethral resection of the prostate (TURP).

PATIENTS AND METHODS

Patients (120) undergoing TURP were irrigated with 1% ethanol in 1.5% glycine solution and their expired air tested for alcohol every 10 min during the procedure.

RESULTS

In all, 112 patients were assessed; over half of the patients absorbed the irrigation fluid and they had a significantly lower postoperative serum sodium concentration (P < 0.002). Fourteen patients (12.5%) absorbed over 500 mL and two (1.8%) developed clinical features of the TUR syndrome. The experience of the surgeon, the weight of resected chips and the operative duration were not significantly predictive of absorption.

CONCLUSION

A tracer amount of ethanol in the irrigant is reliable for detecting absorption. Irrigating fluid absorption was unpredictable, thus supporting the case for routine monitoring.

Polarized human immunodeficiency virus budding in lymphocytes involves a tyrosine-based signal and favors cell-to-cell viral transmission

Maturation and release of human immunodeficiency virus type 1 (HIV-1) is targeted at the pseudopod of infected mononuclear cells. However, the intracellular mechanism or targeting signals leading to this polarized viral maturation are yet to be identified. We have recently demonstrated the presence of a functional YXXL motif for specific targeting of HIV-1 virions to the basolateral membrane surface in polarized epithelial Madin-Darby canine kidney cells (MDCK). Site-directed mutagenesis was used to demonstrate that the membrane-proximal tyrosine in the intracytoplasmic tail of the HIV-1 transmembrane glycoprotein (gp41) is an essential component of this signal. In the present study, immunolocalization of viral budding allowed us to establish that this tyrosine-based signal is involved in determining the exact site of viral release at the surface of infected mononuclear cells. Substitution of the critical tyrosine residue was also shown to increase the amount of envelope glycoprotein at the cell surface, supporting previous suggestions that the tyrosine-based motif can promote endocytosis. Although alteration of the dual polarization-endocytosis motif did not affect the infectivity of cell-free virus, it could play a key role in cell-to-cell viral transmission. Accordingly, chronically infected lymphocytes showed a reduced ability to transmit the mutant virus to a cocultivated cell line. Overall, our data indicate that the YXXL targeting motif of HIV is active in various cell types and could play an important role in viral propagation; this may constitute an alternative target for HIV therapeutics and vaccine development.

MuLV-based vectors pseudotyped with truncated HIV glycoproteins mediate specific gene transfer in CD4+ peripheral blood lymphocytes

Human immunodeficiency virus (HIV) infection ultimately leads to the destruction of the CD4+ lymphocyte subset and the onset of AIDS. In recent years, several gene therapy procedures making use of retroviral vectors that selectively target HIV susceptible cells have been proposed in order to interfere with HIV productive infection. However, the HIV glycoproteins' inability to be incorporated in other heterologous retroviruses considerably limits true HIV cell tropism of such vectors. We now report the use of murine leukemia virus (MuLV) viral particles harboring a truncated form of the HIV glycoprotein for specific gene delivery. Reporter lacZ gene transfer was determined to be appropriately specific to CD4+ cells when HeLaCD4 cells or peripheral blood lymphocytes (PBLs) were infected with these pseudotyped MuLV virus vectors. In contrast, MuLV viruses harboring amphotropic MuLV envelope glycoproteins displayed a broad and nonspecific infection of PBL subpopulations. This new approach, taking advantage of the ability of truncated HIV envelope glycoproteins to be incorporated into heterologous retroviral particles, may foreseeably be used in future interventions based on the coordinated delivery of therapeutic gene products specifically to cell types susceptible to HIV infection.

Human immunodeficiency virus type 1 Vpr is a positive regulator of viral transcription and infectivity in primary human macrophages

It is currently well established that HIV-1 Vpr augments viral replication in primary human macrophages. In its virion-associated form, Vpr has been suggested to aid efficient translocation of the proviral DNA into the cell nucleus. Although Vpr growth-arrests dividing T cells, the relevance of this biological activity in nondividing macrophages is unclear. Here we use Vpr-mutants to demonstrate that the molecular determinants involved in G2-arresting T cells are also involved in increasing viral transcription in macrophages, even though these cells are refractive to the diploid DNA status typical of G2 phase. Our results suggest that the two phenotypes, namely the nuclear localization and the G2-arrest activity of the protein, segregate functionally among the late and early functions of Vpr. The nuclear localization property of Vpr correlates with its ability to effectively target the proviral DNA to the cell nucleus early in the infection, whereas the G2-arrest phenotype correlates with its ability to activate viral transcription after establishment of an infection. These two functions may render Vpr's role essential and not accessory under infection conditions that closely mimic the in vivo situation, that is, primary cells being infected at low viral inputs.

Two distinct oncornaviruses harbor an intracytoplasmic tyrosine-based basolateral targeting signal in their viral envelope glycoprotein

It has been clearly established that the budding of the human immunodeficiency virus (HIV-1), a lentivirus, occurs specifically through the basolateral membrane in polarized epithelial cells. More recently, the signal was assigned to a tyrosine-based motif located in the intracytoplasmic domain of the envelope glycoprotein, as previously observed on various other viral and cellular basolateral proteins. In the present study, expression of human T-cell leukemia virus type 1 (HTLV-1) or Moloney murine leukemia virus envelope glycoproteins was used for trans-complementation of an envelope-negative HIV-1. This demonstrated the potential of oncornaviral retrovirus envelope glycoproteins to confer polarized basolateral budding in epithelial Madin-Darby canine kidney cells (MDCK cells). Site-directed mutagenesis confirmed the importance of a common motif encompassing at least one crucial membrane-proximal intracytoplasmic tyrosine residue. The conservation of a similar basolateral maturation signal in different retroviruses further supports its importance in the biology of this group of viruses.

The membrane-proximal intracytoplasmic tyrosine residue of HIV-1 envelope glycoprotein is critical for basolateral targeting of viral budding in MDCK cells

Budding of retroviruses from polarized epithelial Madin-Darby canine kidney cells (MDCK) takes place specifically at the basolateral membrane surface. This sorting event is suspected to require a specific signal harbored by the viral envelope glycoprotein and it was previously shown that, as for most basolateral proteins, the intracytoplasmic domain plays a crucial role in this targeting phenomenon. It is well known that tyrosine-based motifs are a central element in basolateral targeting signals. In the present study, site-directed mutagenesis was used to generate conservative or non-conservative substitutions of each four intracytoplasmic tyrosines of the human immunodeficiency virus (HIV-1) envelope glycoprotein. This approach revealed that the membrane-proximal tyrosine is essential to ensure both the basolateral localization of envelope glycoprotein and the basolateral targeting of HIV-1 virions. Substitutions of the membrane-proximal tyrosine did not appear to affect incorporation of envelope glycoprotein into the virions, as assayed by virion infectivity and protein content, nor its capability to ensure its role in viral infection, as determined by viral multiplication kinetics. Altogether, these results indicate that the intracytoplasmic domain of the HIV-1 envelope glycoprotein harbors a unique, tyrosine-based, basolateral targeting signal. Such a tyrosine-based targeting signal may play a fundamental role in HIV transmission and pathogenesis.

The intracytoplasmic domain of gp41 mediates polarized budding of human immunodeficiency virus type 1 in MDCK cells

Human immunodeficiency virus type 1 (HIV-1) has been shown to exhibit a specific basolateral release in polarized epithelial cells. Previous investigators have used vaccinia virus recombinants expressing HIV proteins to demonstrate that virus release is nonpolarized in the absence of viral envelope glycoproteins. In this study, we developed a transient expression system which allows the use of Madin-Darby canine kidney polarized epithelial cells directly grown on semipermeable membranes. This procedure allowed us to investigate polarized HIV viral budding following introduction of proviral DNA constructs. Expression of env gene products in trans demonstrated the ability to polarize env-negative viruses in a dose-dependent manner. The targeting signal for polarized virus release was shown to be present in the envelope gp41 transmembrane protein and absent from the gp120 portion of env. At least part of this signal is within the gp41 intracytoplasmic domain. Mutants of the p17gag matrix protein were shown to be nonpolarized only when unable to interact with the envelope glycoproteins. Together, these data are consistent with a model of polarized virus budding in which capsid proteins, lacking a targeting signal, are targeted for specific basolateral release via an interaction of p17 with the envelope glycoprotein containing the polarization signal in its intracytoplasmic domain.

Recurrent cerebral ischemia and mitral valve vegetation in a patient with antiphospholipid antibodies

A 37-year-old woman presented with a history of acute loss of vision in her left eye and a history of recurrent transient ischemic attacks. Subsequent investigations revealed a prolonged PTT. The lupus anticoagulant and anticardiolipin antibodies (aCL) were identified in her serum. A cardiac murmur was heard and echocardiography demonstrated a mass on the mitral valve. Extensive studies for infection were negative. Cardioembolic phenomena were considered a possible cause of her cerebral ischemic events. The occurrence of nonbacterial endocardial verrucae is well described in systemic lupus erythematosus. The pathogenesis of this lesion remains speculative, however, its occurrence in our patient, with a lupus anticoagulant and aCL suggests a possible association. The clinical manifestations of thrombosis in patients with antiphospholipid antibodies are varied, and may include the development of thrombotic endocardial lesions.

Adjuvant effect of bendrofluazide on propranolol in hypertension

A double-blind trial was undertaken to assess the effect of bendro-fluazide in lowering the blood pressure in patients with essential hypertension controlled on propranolol. An increased hypotensive effect was found and the greatest fall occurred in the supine systolic blood pressure. Side-effects were mild and transient and did not interfere with treatment.