In vitro toxicity and internalization of gold nanoparticles (AuNPs) in human epithelial colorectal adenocarcinoma (Caco-2) cells and the human skin keratinocyte (HaCaT) cells.

Ingestion and transdermal delivery are two common routes of nanoparticle (NP) exposure. In this study, the intracellular uptake, cytotoxicity and genotoxicity of 14 nm and 20 nm citrate-stabilized gold nanoparticles (AuNPs), 14 nm polyethylene glycol (PEG)-liganded carboxyl AuNPs, 14 nm PEG-liganded hydroxyl AuNPs and 14 nm PEG-liganded amine AuNPs were assessed on human epithelial colorectal adenocarcinoma (Caco-2) cells and the human skin keratinocyte (HaCaT) cells. The uptake of AuNPs in the cells was confirmed through darkfield microscopy and hyperspectral imaging followed by spectral angle mapping (SAM). A high level of citrate AuNPs was found in both cell lines whilst uptake of PEGylated AuNPs was low, irrespective of their functional groups. Cytotoxicity assessed by cell impedance was only observed for the 14 nm citrate-stabilized AuNPs. Enhanced cell proliferation was also observed in 14 nm PEG-liganded hydroxyl and 14 nm PEG-liganded amine AuNP-treated Caco-2 and HaCaT cells. For the assessment of genotoxicity, the in vitro micronucleus assay was used. Dose-dependent genotoxicity was observed in both Caco-2 and HaCaT cells, with all the AuNPs inducing genotoxicity. In conclusion, the entry of NPs into the cells as well as toxicity was dependent on their physicochemical properties such as surface coating and different chemical functional groups.

Hydrolysis of nitriles by soil bacteria: variation with soil origin.

AIMS: The aim of this study was to explore bacterial soil diversity for nitrile biocatalysts, in particular, those for hydrolysis of ß-substituted nitriles, to the corresponding carboxamides and acids that may be incorporated into peptidomimetics. To achieve this, we needed to compare the efficiency of isolation methods and determine the influence of land use and geographical origin of the soil sample. METHODS AND RESULTS: Nitrile-utilizing bacteria were isolated from various soil environments across a 1000 km long transect of South Africa, including agricultural soil, a gold mine tailing dam and uncultivated soil. The substrate profile of these isolates was determined through element-limited growth studies on seven different aliphatic or aromatic nitriles. A subset of these organisms expressing broad substrate ranges was evaluated for their ability to hydrolyse ß-substituted nitriles (3-amino-3-phenylpropionitrile and 3-hydroxy-4-phenoxybutyronitrile) and the active organisms were found to be Rhodococcus erythropolis from uncultivated soil and Rhodococcus rhodochrous from agricultural soils. CONCLUSIONS: The capacity for hydrolysis of ß-substituted nitriles appears to reside almost exclusively in Rhodococci. Land use has a much greater effect on the biocatalysis substrate profile than geographical location. SIGNIFICANCE AND IMPACT OF THE STUDY: Enzymes are typically substrate specific in their catalytic reactions, and this means that a wide diversity of enzymes is required to provide a comprehensive biocatalysis toolbox. This paper shows that the microbial diversity of nitrile hydrolysis activity can be targeted according to land utilization. Nitrile biocatalysis is a green chemical method for the enzymatic production of amides and carboxylic acids that has industrial applications, such as in the synthesis of acrylamide and nicotinamide. The biocatalysts discovered in this study may be applied to the synthesis of peptidomimetics which are an important class of therapeutic compounds.

Characterisation of two bifunctional cellulase-xylanase enzymes isolated from a bovine rumen metagenome library.

Ruminant digestive tract microbes hydrolyse plant biomass, and the application of metagenomic techniques can provide good coverage of their glycosyl hydrolase enzymes. A metagenomic library of circa 70,000 fosmids was constructed from bacterial DNA isolated from bovine rumen and subsequently screened for cellulose hydrolysing activities on a CMC agar medium. Two clones were selected based on large clearance zones on the CMC agar plates. Following nucleotide sequencing, translational analysis and homology searches, two cellulase encoding genes (cel5A and cel5B) belonging to the glycosyl hydrolyse family 5 were identified. Both genes encoded pre-proteins of about 62 kDa, containing signal leader peptides which could be cleaved to form mature proteins of about 60 kDa. Biochemical characterisation revealed that both enzymes showed alkaline pH optima of 9.0 and the temperature optima of 65 °C. Substrate specificity profiling of the two enzymes using 1,4-ß-D-cello- and xylo-oligosaccharides revealed preference for longer oligosaccharides (n ≥ 3) for both enzymes, suggesting that they are endo-cellulases/xylanases. The bifunctional properties of the two identified enzymes render them potentially useful in degrading the ß-1,4 bonds of both the cellulose and hemicellulose polymers.

Differential sperm motility scoring and sperm ATP concentrations.

Sperm motility is one of the most important parameters in semen analysis. In this study the motility scoring method of Hellinga was used. Adenosine triphosphate (ATP) is the main energy source used by the sperm flagellum to initiate and propagate forward motility. This study was conducted to evaluate the interrelationships between sperm ATP and differential motility. The differential motility method supplemented the conventional by which the quantitative and qualitative motility were estimated. There was a good correlation between the differential motility scoring method and sperm [ATP], although the latter did not necessarily improve the diagnostic capacity.

High seminal sialic acid concentrations in patients with severe teratozoospermia.

Seminal plasma and sperm-bound sialic acid (SA) concentrations were evaluated in patients with severe teratozoospermia (less than 5% morphologically normal sperm) and correlated with values of a control group with greater than 20% morphologically normal sperm. The SA concentrations both in seminal plasma and on sperm were significantly higher in teratozoospermia, but the ratio of sperm-bound SA to seminal plasma SA remained virtually the same. The causes and consequences of high SA in these patients need further study.

alpha-Glucosidase, sperm ATP concentrations, and epididymal function.

It has been suggested that alpha-glucosidase may be a marker of epididymal patency and function. Spermatozoal ATP concentrations decrease during passage through the epididymis, indicating efficient maturation. We correlated sperm motility with seminal plasma alpha-glucosidase activity and spermatozoal ATP. The sperm motility correlation with alpha-glucosidase activity was significantly positive, and the sperm motility correlation with spermatozoal ATP was significantly negative. It appears that high-alpha-glucosidase activity and low-spermatozoal ATP were present in semen with good sperm motility and could possibly indicate efficient epididymal function.

Impaired epididymal function in patients with detached ciliary tufts in semen: a preliminary report.

Low spermatozoal ATP concentration in the presence of high alpha-glucosidase activity may indicate efficient epididymal function. It was suggested that detached ciliary tufts (DCTs) originated from the epididymis. We compared the spermatozoal ATP concentration and alpha-glucosidase activity in semen of patients with DCTs to that of a control group. Higher ATP concentration and lower alpha-glucosidase activity were found in patients with DCTs in their semen compared to the control group. These results might probably point out impaired epididymal function and further support the proposed epididymal origin of these tufts.

Alpha-glucosidase activity and sperm motility.

We correlated the activity of alpha-glucosidase in seminal plasma with the motility and differential motility of sperm. Significant positive correlations were found between the alpha-glucosidase activity and both motility and the percentage sperm with good forward progression. This supports the use of alpha-glucosidase in semen as a marker of epididymal function and specifically of the development of motility.

[The use of medicines by children attending the outpatient clinic at Kafalong Hospital]. / Gebruik van medisyne deur kinders wat die buitepasiëntkliniek, Kalafong-hospitaal, besoek het.

Repeated visits by some children to the outpatient department of Kalafong Hospital seem to cast doubt on the efficacy of treatment taken at home. Four hundred persons accompanying children less than 14 years of age were interviewed. Most of the children were less than 6 years old, with a mean age of 36.6 months. Three or fewer drugs were issued to more than 80% of the children and 72% of the accompanying adults in this group knew the correct dosage. However, when 4 or more items were issued, only 52% knew the correct dosage. Understanding of the required duration of therapy was inadequate. The correct administration of the prescribed drugs correlated well with a higher education of the patient escorts. People living in the urban areas were better educated and had fewer children than those from rural localities. Some recommendations are made to improve drug administration by supervising adults.

Exogenous ochronosis: an epidemiological study.

A survey was conducted to investigate the relationship between exogenous ochronosis and the use of skin lightening preparations amongst black individuals attending general outpatient departments in two South African hospitals. In the sample, 15% of males and 42% of females were found to have exogenous ochronosis. The prevalence amongst users of skin lighteners was 69%. The main demographic associations with ochronosis were an inverse relationship to education, and predominance of the female sex. Clinical and behavioural aspects were also recorded. Even products limited to 2% hydroquinone or less, and combined with a sunscreen, were found to cause ochronosis.

Treatment and prognosis of metastatic carcinoma of unknown primary: analysis of 100 patients.

One hundred patients with metastatic carcinoma of unknown primary were analyzed to assess the importance of prognostic factors on survival. Patients were treated with cytostatic combinations, single drugs, or symptomatic care only. Response in the treatment groups ranged from 10% to 33%. The median survival of all patients was 124 days. In a univariate analysis good performance status, the presence of lymph node metastases, and the absence of liver metastases favorably influenced survival. In a Cox proportional hazards model, good performance status contributed significantly to a better survival. In addition there was a trend for female patients, patients with lymph node metastases, and patients without liver metastases to survive longer. These patient subsets deserve optimal treatment despite the dismal prognosis of this disease.

A progressive radiorenographic (99mTc-DTPA) presentation of surgically induced renal vein hypertension in baboons.

A 99mTc-DTPA radiorenographic study, supported by excretory urography, blood chemistry and eventually histology was performed on 8 chacma baboons (Papio ursinus) after surgical induction of unilateral renal vein hypertension. Frequent sequential repeat renograms during 6 post-operative months detected fluctuating renal behaviour but did not reveal typical course of the disease. Neither did any one of the radiorenographic parameters (TP, T1/2, FF, relative clearances and perfusion) prove to be more sensitive than the others in detecting abnormalities. Initial microscopic or macroscopic haematuria and proteinuria in general eventually cleared up. Light microscopy demonstrated only mild abnormalities. The effects of venous occlusion of the kidney and the prognosis seemed to be variable as was reflected by radiorenography.