Publications by authors named "Constance E J VAN Rensburg"

Introduction: Clinicians' skepticism, fueled by evidence of inferiority of some multisource generic antimicrobial products, results in the underutilization of more cost-effective generics, especially in critically ill patients. The aim of this observational study was to demonstrate equivalence between the generic or comparator brand of meropenem (Mercide) and the leading innovator brand (Meronem) by means of an ex vivo technique whereby antimicrobial activity is used to estimate plasma concentration of the active moiety.

Methods: Patients from different high care and intensive care units were recruited for observation when prescribed either of the meropenem brands under investigation.

View Article and Find Full Text PDF

Humic substances are effective in the suppression of delayed type hypersensitivity, rat paw oedema, a graft-versus-host reaction and contact hypersensitivity in rats. They reduce the C-reactive protein levels of patients suffering from osteoarthritis of the knee and the wheel and flare reaction of patients suffering from hay fever. They have also been described as cardioprotective and pro-angiogenic.

View Article and Find Full Text PDF

Background: Ferrocene-containing β-diketones and cisplatin, [(NH(3))(2)PtCl(2)], possess strong antineoplastic activity. No information is available regarding the anticancer activity of the corresponding ruthenocene complexes. This study examined the cytotoxicity of stable ruthenocene-containing β-diketones.

View Article and Find Full Text PDF

Background: The water-soluble ionic gold(I) complex [Au(PPh(2)CH(2)CH(2)PPh(2))(2)]Cl possesses at least ten times stronger antineoplastic activity than the water-soluble neutral silver(I) carboxylates [AgO(2)C(CH(2)OCH(2))(n)H], 1, (n=1), 2 (n=2), or 3 (n=3) even though Au(I) and Ag(I) are isoelectronic d(10) metals lying one above the other in the periodic table of the elements. In this study we determined the cytotoxicity of the stable water-soluble gold(I) carboxylates [(Ph(3)P)AuO(2)C(CH(2)OCH(2))(n)H], 4 (n=1), 5 (n=2) and 6 (n=3) to compare the intrinsic antineoplastic activity of gold(I) and silver(I) under conditions where different complex charges do not influence the result.

Materials And Methods: The cytotoxicity of carboxylato gold complexes 4-6 towards the HeLa (human cervix epithelioid) cancer cell line ATCC CCL-2, resting lymphocytes and phytohaemagglutinin(PHA)-stimulated lymphocytes were determined.

View Article and Find Full Text PDF

A series of new neutral mononuclear or dinuclear gold(I) complexes and a cyclic cationic tetranuclear amidogold(I) complex comprising of the phosphines 1,2-bis(dimethylphosphino)ethane (dmpe), μ-1,2-bis(diphenylphosphino)ethane (dppe), μ-1,3-bis(diphenylphosphino)propane (dppp), μ-1,5-bis(diphenylphosphino)pentane (dpppe), μ-1,6-bis(diphenylphosphino)hexane (dpph) or trimethylphosphine, and several N-heterocyclic ring systems (imidazolate, pyrazolate, 1,2,3-triazolate, 1,2,4-triazolate, pyrrolate, 9H-purine-9-ate or 9H-purine-6-amine-9-ate) as ligands, reveal intermolecular aurophilic interactions and 2D channels available for solvent molecules in some of their crystal structures. The antitumour activity of the acyclic gold(I) compounds is highly dependent on the substituents on the phosphorus atoms being highest for phenyl groups and lower for methyl groups. The activity of these compounds against selected cell lines is linked to the length of the carbon bridge between the two phosphorus atoms being highest with a bridge consisting of 5 or 6 carbons.

View Article and Find Full Text PDF

Background: The purpose of this research was to determine the acute and subacute safety and proof-of-concept efficacy of carbohydrate-derived fulvic acid (CHD-FA).

Methods: In this double-blind study, 30 male volunteers with predetermined atopy were randomly assigned to either Group A or Group B, each consisting of 15 participants. In part 1 of the study, the groups were administered increasing amounts of CHD-FA, ranging from 5 mL to 40 mL, provided that no adverse events had occurred at the previous dosage.

View Article and Find Full Text PDF

Background: Gold(I) and platinum(II) d(10) and d(8) electronic complexes such as (Au(PPh(2)CH(2)CH(2)PPh(2))(2))Cl and cisplatin, ((H(3)N)(2)PtCl(2)), possess strong antineoplastic activities. Almost no information is available regarding the anticancer activity of isoelectronic silver(I) d(10) complexes. This study examined the cytotoxicity of stable water-soluble silver(I) carboxylates.

View Article and Find Full Text PDF

4-Aminoquinolines were hybridized with artemisinin and 1,4-naphthoquinone derivatives via the Ugi-four-component condensation reaction, and their biological activities investigated. The artemisinin-containing compounds 6a-c and its salt 6c-citrate were the most active target compounds in the antiplasmodial assays. However, despite the potent in vitro activities, they also displayed cytotoxicity against a mammalian cell-line, and had lower therapeutic indices than chloroquine.

View Article and Find Full Text PDF

Background: Ferrocene derivatives may possess antineoplastic activity. Those with low ferrocenyl reduction potentials often have the highest anticancer activity, as cell components have to oxidise them to the active ferrocenium species before cytotoxicity can be recorded. Some gold(I) complexes also possess anticancer activity.

View Article and Find Full Text PDF

A series of dihydroartemisinin derivatives were synthesized via an aza-Michael addition reaction to a dihydroartemisinin-based acrylate and were evaluated for antiplasmodial and antitumor activity. The target compounds showed excellent antiplasmodial activity, with dihydroartemisinin derivatives 5, 7, 9 and 13 exhibiting IC(50) values of ≤10 nM against both D10 and Dd2 strains of Plasmodium falciparum. Derivative 4d was the most active against the HeLa cancer cell line, with an IC(50) of 0.

View Article and Find Full Text PDF

It has been shown in a previous study that brown coal-derived potassium humate is safe and effective in suppressing contact hypersensitivity in rats. In this study the efficacy of potassium humate on other types of inflammation was determined. Preparative TLC followed by mass spectroscopy was used in an attempt to fingerprint the product.

View Article and Find Full Text PDF

The effects of brown coal derived potassium humate on lymphocyte proliferation, cytokine production and complement activation were investigated in vitro. Potassium humate increased lymphocyte proliferation of phytohaemaglutinin A (PHA) and pokeweed mitogen (PWM) stimulated mononuclear lymphocytes (MNL) in vitro from concentrations of 20 to 80 microg/ml, in a dose dependant manner. On the other hand potassium humate, at 40 microg/ml, significantly inhibited the release of TNF-alpha, IL-1beta, IL-6 and IL-10 by PHA stimulated MNL.

View Article and Find Full Text PDF

Background: Oxidised ferrocenium compounds often possess antineoplastic activity. In contrast, reduced ferrocene derivatives frequently only show activity if cell components can oxidise them inside cells to the ferrocenium species. Ferrocene compounds having the lowest formal reduction potential are normally expected to be the most cytotoxic.

View Article and Find Full Text PDF

Background: Often potentially good chemotherapeutic drugs find limited clinical use due to the many negative medical and physical side-effects they may exhibit. To combat these negative side-effects, new antineoplastic materials are continuously being synthesised and evaluated. Ferrocene-containing compounds under certain conditions may show appreciable anticancer activity.

View Article and Find Full Text PDF

New 7-chloroquinolinyl thiourea derivatives derived from the corresponding 4,7-dichloroquinoline isothiocyanate were synthesized and evaluated for in vitro antimalarial and anticancer activity. The most active compound from the series displayed an inhibitory IC(50) value of 1.2 microM against the D10 strain of Plasmodium falciparum.

View Article and Find Full Text PDF

Crude methanol and water extracts of 36 plants, employed in the treatment of diseases of probable bacterial etiology by the Venda people, were screened for antibacterial activity. Combretum molle, Peltophorum africanum, Piper capense, Terminalia sericea and Zanthoxylum davyi were the most active and presented MIC values < or =1.00 mg/ml.

View Article and Find Full Text PDF

Background: Tumour hypoxia severely limits the success of radiotherapy. Radiosensitization of hypoxic tumour cells by drugs is thus an important clinical issue.

Materials And Methods: Two novel ferrocene-containing beta-diketonato complexes of the transition metals rhodium and iridium were examined for their cytotoxic activity against Chinese hamster ovary (CHO) cells by MTT and clonogenic assays.

View Article and Find Full Text PDF

Background: A dramatic increase in multiple-drug-resistant (MDR) Gram-positive pathogens has occurred in recent times, leading to increased rates or morbidity and mortality and also associated with high costs for the treatment of these infections. It is clear that there is an urgent need for the development of effective antimicrobial agents. The anti-bacterial activity of seven 2,2,6,6-tetramethylpiperidine (TMP)-substituted phenazines, compared to clofazimine (B663), were tested against 70 clinical isolates of methicillin-resistant Staphylococcus aureus, MDR Streptococcus pneumoniae and resistant Enterococcus sp.

View Article and Find Full Text PDF

In this study the anti-inflammatory potential of potassium humate, derived from bituminous coal, has been investigated in vitro. Exposure of resting and phorbol-12-myristate-13-acetate (PMA) stimulated human neutrophils to potassium humate resulted in a decreased expression of CR3 by activated, but not resting cells, in a dose-related way. Humate also inhibited the adhesion of PMA-stimulated neutrophils to a baby hamster kidney cell line expressing ICAM1 (the CR3 ligand) (BHK331-7).

View Article and Find Full Text PDF

One of the best-known multi-purpose medicinal plants in Southern Africa, Sutherlandia frutescens subsp. microphylla (family: Fabaceae/Leguminosa), is used for a wide range of conditions, including cancer, viral diseases and inflammatory conditions. Little scientific data has been documented on the mechanism by which Sutherlandia frutescens acts on the immune system.

View Article and Find Full Text PDF

A unique process has been developed to convert bituminous coal by controlled wet oxidation followed by base treatment to a water-soluble humate called oxihumate. The effects of oxihumate on the proliferative response of lymphocytes has been studied in vitro and ex vivo. Oxihumate increased the proliferative response of phytohaemagglutinin-stimulated human lymphocytes, from a concentration of 20 microg/ml and upwards.

View Article and Find Full Text PDF

Background: Mixed-valent diruthenium tetracarboxylate complexes were shown to have slight antineoplastic activity against P388 leukemia cell lines. However these complexes suffered from poor water-solubility, which may have detrimentally affected their activity.

Materials And Methods: Mixed-valent diruthenium tetracarboxylates of the type [Ru2(O2CR)4(L)2] (PF6) with L = imidazole, 1-methylimidazole and H2O when R = CH3, L = ethanol when R = Fc (ferrocenyl) or Fc-CH=CH- and of the type M3[Ru2(O2CR)4(H2O)2]4H2O, M = Na+ when R = m-C6H4SO3- and M = K+ when R = p-C6H4SO3-, were tested for cytotoxicity against HeLa and multidrug resistant CoLo 320DM human cancer cell lines.

View Article and Find Full Text PDF