Expression of DC-SIGN and DC-SIGNRs in placentas of HIV-positive patients

Background. Human dendritic cell-specific intracellular adhesion molecule-3 (ICAM3)-grabbing non-integrin (DC-SIGN) is a mannose-binding lectin that initiates interaction between dendritic cells and resting T-lymphocytes. DC-SIGN is highly expressed in placental tissue on dendritic cells and Hofbauer cells, and it is suggested that HIV may become adsorbed to DC-SIGN on Hofbauer cells as part of the mechanism of mother-to-child HIV transmission. A possible mechanism of transfer of the virus from the Hofbauer cells to the fetus is the subsequent adsorption to DC-SIGN-related molecules (DC-SIGNRs), present on immediately adjacent capillary vascular endothelium. However, data on DC-SIGN and DC-SIGNR expression in the placenta are few. Methods. Forty term placentas from HIV-positive mothers and 21 term placentas from HIV-negative mothers underwent immunohistochemistry staining for DC-SIGN and DC-SIGNR expression. Five random sets of 10 villi were assessed, and the average number of positive cells were counted in each case. In addition, where possible, maternal and cord blood viral loads and maternal CD4+ counts were performed in the HIV-positive group only. Results. The median maternal CD4+ count was 377 cells/μl and 27% of participants had undetectable viral loads; the median detectable viral load was 3.72 log. Most (97%) of the cord bloods tested in infants from HIV-positive mothers had lower than detectable viral loads. HIV-positive cases had significantly greater expression of both DC-SIGNRs (median values in HIV-positive cases, 14.5 positive cells/10 villi (pc/10villi), compared with 11 pc/10villi in HIV-negative cases, p=0.020) and DC-SIGN (median value in HIV-positive cases, 26.5 pc/10villi, compared with 23 pc/10villi in HIV-negative cases, p=0.037). DC-SIGNR expression was also noted in Hofbauer cells and decidual macrophages in addition to endothelium (reported currently). There was no difference in expression of DC-SIGN and DC-SIGNRs in patients with or without chorioamnionitis, but there was an inverse relationship between DC-SIGN and DC-SIGNR expression and maternal CD4+ counts in HIV-positive cases. Conclusion. Both DC-SIGN and DC-SIGNR expression were higher in placentas from HIV-positive mothers compared with HIV-negative cases. These lectins may be potential new therapeutic targets for preventing vertical transmission of HIV

Short communication: The effect of ultrasound at 256 KHz on Microcystis aeruginosa, with and without gas vacuoles

The effect of ultrasound on the growth of M. aeruginosa confirmed to contain gas vacuoles and on a laboratory culture with no gas vacuoles was investigated. Both cultures were treated continuously for 9 d with an ultrasonic flow device. To evaluate the influence of ultrasound during the treatment, the chlorophyll-a concentration was measured daily. Furthermore, changes in culture characteristics, e.g., flotation and gas vesicle formation, were determined. The results showed that, in contrast to the control, both ultrasonic-treated cultures had a lower chlorophyll-a concentration and cell aggregates were disrupted. Transmission electron microscopy confirmed a collapse of gas vacuoles in the environmental culture, while the laboratory culture, which did not contain gas vacuoles, showed many membrane-damaged cells. It was concluded that ultrasonic treatment of M. aeruginosa caused the disruption of gas vacuoles and destruction of cell membranes.Keywords: Ultrasound, cyanobacteria, Microcystis aeruginosa, chlorophyll, gas vacuole

Expression of DC-SIGN and DC-SIGNRs in placentas of HIV-positive patients

Background. Human dendritic cell-specific intracellular adhesion molecule-3 (ICAM3)-grabbing non-integrin (DC-SIGN) is a mannose-binding lectin that initiates interaction between dendritic cells and resting T-lymphocytes. DC-SIGN is highly expressed in placental tissue on dendritic cells and Hofbauer cells, and it is suggested that HIV may become adsorbed to DC-SIGN on Hofbauer cells as part of the mechanism of mother-to-child HIV transmission. A possible mechanism of transfer of the virus from the Hofbauer cells to the fetus is the subsequent adsorption to DC-SIGN-related molecules (DC-SIGNRs), present on immediately adjacent capillary vascular endothelium. However, data on DC-SIGN and DC-SIGNR expression in the placenta are few. Methods. Forty term placentas from HIV-positive mothers and 21 term placentas from HIV-negative mothers underwent immunohistochemistry staining for DC-SIGN and DC-SIGNR expression. Five random sets of 10 villi were assessed, and the average number of positive cells were counted in each case. In addition, where possible, maternal and cord blood viral loads and maternal CD4+ counts were performed in the HIV-positive group only. Results. The median maternal CD4+ count was 377 cells/µl and 27% of participants had undetectable viral loads; the median detectable viral load was 3.72 log. Most (97%) of the cord bloods tested in infants from HIV-positive mothers had lower than detectable viral loads. HIV-positive cases had significantly greater expression of both DC-SIGNRs (median values in HIV-positive cases, 14.5 positive cells/10 villi (pc/10villi), compared with 11 pc/10villi in HIV-negative cases, p=0.020) and DC-SIGN (median value in HIV-positive cases, 26.5 pc/10villi, compared with 23 pc/10villi in HIV-negative cases, p=0.037). DC-SIGNR expression was also noted in Hofbauer cells and decidual macrophages in addition to endothelium (reported currently). There was no difference in expression of DC-SIGN and DC-SIGNRs in patients with or without chorioamnionitis, but there was an inverse relationship between DC-SIGN and DC-SIGNR expression and maternal CD4+ counts in HIV-positive cases.  Conclusion. Both DC-SIGN and DC-SIGNR expression were higher in placentas from HIV-positive mothers compared with HIV-negative cases. These lectins may be potential new therapeutic targets for preventing vertical transmission of HIV

The clinical utility and cost effectiveness of routine thyroid screening in adult psychiatric patients presenting at Stikland Hospital, Cape Town, South Africa

Objective: The use of thyroid tests to assess psychiatric patients remains debatable. Therefore, this study was conducted to examine the utility and cost effectiveness of the current protocol used in thyroid testing in adult psychiatric patients presenting at Stikland Hospital, Cape Town, South Africa. Method: This was a retrospective chart review conducted at Stikland Hospital between 1 January 2000 and 31 December 2005. The following data was recorded: demographic variables, clinical diagnoses at admission and discharge, number of days from admission to a thyroid test request, the reason for thyroid screening, number of thyroid tests, their yield and costs involved, as well as the action taken following an abnormal thyroid test result. Results: The mean age of patients (n = 1080: n = 364 male, n = 716 female) was 42.8 years (SD ±16.6). Pre-existing thyroid disease was documented in 70 (6%) of patients. Normal Thyroid Stimulating Hormone (TSH) test results significantly (p = 0.0001) increased, whilst abnormal TSH test results significantly (p = 0.0001) decreased from baseline to follow-up. Except for gender, the outcome of TSH screening was independent of demographic and clinical diagnoses. Only 16% of TSH tests yielded clinically significant results. Conclusion: The findings of this study do not support the early, routine screening for thyroid dysfunction in psychiatric patients at this facility. It is possible that thyroid screening may present with transient abnormalities of no particular clinical significance, and would therefore not be a cost effective practice.Keywords: Psychiatry; Screening; Thyroid abnormality; Thyroid stimulating hormon

An investigation of impact breakage of rocks using the split Hopkinson pressure bar

Discrete element methods (DEM) are being used to provide detailed impact histories of the particles in comminution devices, such as mills. To match this immense detail of information, far more informative breakage tests than those that are generally conducted are now required. The split Hopkinson pressure bar apparatus is used in this study, as it allows the calculation of breakage forces and absorbed energies. The geometry of rock particles has been identified as significant, so this project undertook to identify the influence of shape on the breakage pattern of blue stone. Comparisons are then made between the breakage pattern of angular rocks and rounded, milled rocks for single impact fracture and consecutive impact loading at low energy. Results of this experiment indicate that although breakage for both geometries occurs over a similar energy range, rounded particles have the greater probability of fracture because they absorb more of the impact energy for a given loading. Size distributions of progeny show that five pebbles or more are sufficient to predict the distribution of most particles in small energy regimes. Cumulative impact testing shows that considerably more energy is required to break a rock through cumulative damage than through a single impact—this is of considerable importance in the light of the indications from DEM simulations that most breakage in a mill will be from cumulative damage rather than single impact breakage

Technical note The formulation of synthetic domestic wastewater sludge medium to study anaerobic biological treatment of acid mine drainage in the laboratory

Requirements for successful biological treatment of acid mine drainage (AMD) rely on the reduction of sulphates by microorganisms using a suitable organic carbon source. Various carbon sources, such as domestic wastewater sludge, have previously been used in the semi-passive biological treatment of  AMD. Domestic wastewater sludge is however highly variable in its composition, making laboratory  experimentation difficult. Synthetic medium was therefore formulated based on the chemical oxygen demand (COD) and the biological degradable organic matter (BOD) of domestic wastewater sludge. Four synthetic media compositions were formulated consisting of different ratios of meat extract,  vegetable extract, sodium chloride, potassium phosphate, urea, ammonium chloride, iron sulphate, magnesium sulphate and glucose. The media composition with BOD and COD measurements closest to that of anaerobic domestic wastewater sludge was selected for further studies. The combination of AMD to synthetic wastewater sludge in 3 ratios was determined for COD and sulphate reduction in bioreactors over a period of 90 d. The highest reduction of 86.76% in COD and 99.22% in sulphate content were obtained in a 1:1 AMD: synthetic domestic wastewater sludge (SDWWS) ratio that calculated to a COD/sulphate ratio of 3.Keywords: acid mine drainage, synthetic domestic wastewater sludge, sulphates, CO

Evaluation of a Lagrangian Discrete Phase Modeling Approach for Application to Industrial Scale Bubbling Fluidized Beds

Industrial scale bubbling fluidized bed simulations were carried out within the Kinetic Theory of Granular Flows (KTGF). The KTGF was applied within two different modelling frameworks, the traditional Two Fluid Model (TFM) and a new approach in the form of the Dense Discrete Phase Model (DDPM), in order to identify any differences in performance. Only the DDPM was able to attain fully grid independent results for industrial scale 2D simulations. In fact, the performance was sufficiently good to enable the completion of reasonably affordable full 3D simulations. These simulations revealed some differences between 2D and 3D, but the global system behaviour remained relatively similar. Comparisons to experimental pressure drop data for both 2D and 3D simulations were acceptable

A retrospective review of trends and clinical characteristics of methamphetamine-related acute psychiatric admissions in a South African context

Objective: Epidemiological studies indicate that methamphetamine (MA) abuse poses a major challenge to health in the Western Cape. The objectives of this study were to retrospectively assess the trends, clinical characteristics and treatment demand of MArelated admissions to a psychiatric ward in this region. Method: The clinical records of patients admitted to an acute psychiatric admission ward at Tygerberg Hospital from 1 January 2002 to 30 June 2002 and 1 January 2006 to 30 June 2006, were retrospectively reviewed. Admission numbers including those of adolescent and adult substance users were compared for both study periods. Study samples comparing demographic profile, admission status, length of stay, psychopathology, treatment requirements and referral pattern to other disciplines between MA users and non-users were collected for the 2006 period. Results: There was a significant (

Assessment of the genetic diversity of geographical unrelated Microcystis aeruginosa strains using amplified fragment length polymorphisms (AFLPs)

Molecular marker analysis is becoming increasingly capable of identifying informative genetic variation. Amplified fragment length polymorphism markers (AFLPs) are among the recent innovations in genetic marker technologies, and provide a greater capacity for genome coverage and more reproducible results than previous technologies. We have investigated the usefulness of AFLP, which is based on the selective amplification of genomic restriction fragments by PCR, to differentiate between geographical unrelated Microcystis strains. In total 23 strains were subjected to the AFLP fingerprinting. After analysis of the data on the basis of the average linkage method, known as the Unweighted Pair Group Method using Arithmetic averages (UPGMA), a dendrogram with four clusters was obtained. Cluster 1 consisted mainly of the NIES strains that originated from Japan, while in cluster 2 the European strains grouped together. The South African strains that originated from the northern part of the country group together in cluster 3, while the strains collected from the central and southern regions group together with the US strains in cluster 4. The study had reveals extensive evidence for the applicability of AFLP in cyanobacterial taxonomy, and furthermore clearly demonstrates the superior discriminative power of AFLP towards the differentiation of geographical unrelated Microcystis aeruginosa strains that belong to the same species, as well as highlighting the potential of this fingerprinting method in evolutionary studies.African Journal of Biotechnology Vol. 4 (5), pp. 389-399, 200