Cytotoxic and antimalarial azaphilones from Chaetomium longirostre

Four new azaphilones named longirostrerones A-D (1-4) and three known sterols, ergosteryl palmitate, ergosterol, and ergosterol peroxide, have been isolated from ethyl acetate extract of the fungus Chaetomium longirostre. These structures were determined by 1D and 2D NMR, IR, UV, MS, and CD spectroscopy. Compounds 1-4 exhibited strong cytotoxicity against KB cancer cell lines (IC(50) 0.23-6.38 μM), while only 1 showed potent cytotoxicity against MCF7 and NCI-H187 cell lines (IC50 0.24 and 3.08 μM, respectively). In addition, 1-3 showed antimalarial activity against Plasmodium falciparum (IC50 0.62-3.73 μM).     

The 2008 cholera epidemic in Zimbabwe: experience of the icddr,b team in the field

During August 2008-June 2009, an estimated 95,531 suspected cases of cholera and 4,282 deaths due to cholera were reported during the 2008 cholera outbreak in Zimbabwe. Despite the efforts by local and international organizations supported by the Zimbabwean Ministry of Health and Child Welfare in the establishment of cholera treatment centres throughout the country, the case-fatality rate (CFR) was much higher than expected. Over two-thirds of the deaths occurred in areas without access to treatment facilities, with the highest CFRs (>5%) reported from Masvingo, Manicaland, Mashonaland West, Mashonaland East, Midland, and Matabeleland North provinces. Some factors attributing to this high CFR included inappropriate cholera case management with inadequate use of oral rehydration therapy, inappropriate use of antibiotics, and a shortage of experienced healthcare professionals. The breakdown of both potable water and sanitation systems and the widespread contamination of available drinking-water sources were also considered responsible for the rapid and widespread distribution of the epidemic throughout the country. Training of healthcare professionals on appropriate cholera case management and implementation of recommended strategies to reduce the environmental contamination of drinking-water sources could have contributed to the progressive reduction in number of cases and deaths as observed at the end of February 2009.     

Cytotoxic lasiodiplodin derivatives from the fungus <Emphasis Type="Italic">Syncephalastrum racemosum</Emphasis>

Chemical investigation of fungal biomass of the fungus Syncephalastrum racemosum led to the isolation of new natural products (3R),(5S)-5-hydroxy-de-O-methyllasiodiplodin (1), 6-oxode-O-methyllasiodiplodin (2), in addition to five known compounds, de-O-methyllasiodiplodin (3), lasiodiplodin (4), (3R),(5R)-5-hydroxy-de-O-methyllasiodiplodin (5), ergosterol (6), and ergosterol peroxide (7). Their structures were elucidated by spectroscopic techniques. The absolute configuration of 1 was determined by a modified Mosher’s method. Compound 1 showed cytotoxicity against cholangiocarcinoma, KKU-M139, KKU-M156, and KKU-M213 cell lines with IC₅₀ values in the range of 14–19 μg/mL, while 3 showed cytotoxicity against KB, BC1, and NCI-H187 cell lines with IC₅₀ values of 12.67, 9.65, and 11.07 μg/mL, respectively.     

Human monoclonal single chain antibodies (HuScFv) that bind to the polymerase proteins of influenza A virus

Current anti-influenza drugs target the viral neuraminidase or inhibit the function of the ion channel M2 protein. Not only is the supply of these drugs unlikely to meet the demand during a large influenza epidemic/ pandemic, but also has an emergence of drug resistant influenza virus variants been documented. Thus a new effective drug or antiviral alternative is required. The influenza virus RNA polymerase complex consists of nucleoproteins (NP) that bind to three polymerase subunits: two basic polymerases, PB1 and PB2, and an acidic polymerase (PA). These proteins play a pivotal role in the virus life cycle; thus they are potential targets for the development of new anti-influenza agents. In this study, we produced human monoclonal antibodies that bound to the influenza A polymerase proteins by using a human antibody phage display library. Complementary DNA was prepared from the total RNA of a highly pathogenic avian influenza (HPAI) virus: A/duck/Thailand/144/2005(H5N1). The cDNA synthesized from the total virus RNA was used as template for the amplification of the gene segments encoding the N-terminal halves of the PB1, PB2 and PA polymerase proteins which encompassed the biologically active portions of the respective proteins. The cDNA amplicons were individually cloned into appropriate vectors and the recombinant vectors were introduced into Escherichia coli bacteria. Transformed E. coli clones were selected, and induced to express the recombinant proteins. Individually purified proteins were used as antigens in bio-panning to select the phage clones displaying specific human monoclonal single chain variable fragments (HuScFv) from a human antibody phage display library constructed from Thai blood donors in our laboratory. The purified HuScFv that bound specifically to the recombinant polymerase proteins were prepared. The inhibitory effects on the biological functions of the respective polymerase proteins should be tested. We envisage the use of the HuScFv in their cell penetrating version (transbodies) as an alternative influenza therapeutic to current anti-virus drugs.     

Launching a paradigm for first and redo-surgery in primary congenital glaucoma: institutional experience

AIM: To evaluate the outcome of the initial and the redo-surgeries for primary congenital glaucoma (PCG) correlated to its degree of severity. METHODS: A retrospective study involved patients with PCG presented between 2010 and 2018. Medical records were reviewed to assess the degree of the preoperative severity according to the intraocular pressure (IOP), corneal diameter and corneal edema. Success and failure rates were calculated for both first and redo-surgeries at 6 and 12mo respectively then correlated to the severity of the cases. RESULTS: Complete records were retrieved for 272 eyes (153 patients) with PCG: 43 eyes were mild, 136 moderate and 93 severe. Combined trabeculotomy and trabeculectomy (CTT) had the highest success rate in moderate (96.4%) and severe cases (59.3%) while trabeculotomy had the highest success rate in mild cases (96.3%). Medical records of 88 eyes (63 patients) with recurrent PCG were analyzed, most with severe presentation (59 eyes). Ahmed glaucoma valve (AGV) was used in 67 (76%) eyes and augmented trabeculectomy in 21 (24%) eyes. At 12mo, there was no statistically significant difference between both surgeries in total success rate (P=0.256). For mild cases, success rate was 100% for both surgeries. Severe cases had higher success rates following AGV (87%) than augmented trabeculectomy (20%). Preoperative severity of the disease was an independent factor affecting the failure rate in secondary trabeculectomy but not in AGV. Patients younger than 24mo had higher probabilities of failure following both redo-surgeries with hazard ratio =1.325 and 0.37 for augmented trabeculectomy and AGV respectively. CONCLUSION: Preoperative assessment of the severity of eyes with PCG helps in the selecting the optimal primary and secondary surgery. For first surgery, trabeculotomy is more effective in mild cases whereas; CTT and augmented subscleral trabeculectomy (SST) are appropriate for moderate and severe cases. AGV proved to be superior to augmented SST in severe recurrent cases.     

Traumatic pericardial tamponade: relearning old lessons.

Traumatic pericardial tamponade is a serious and rapidly fatal injury. As penetrating chest wounds are becoming more common, early diagnosis of tamponade is important so that life saving treatment can be started. The classical features of tamponade may be modified by hypovolaemia and the presence of associated injuries; acute tamponade may also be precipitated by rapid administration of large volumes of fluid. Pericardiocentesis, while sometimes life saving, is dangerous and of limited value. Echocardiography is limited by availability and operator dependence. A high degree of clinical suspicion in patients with chest injuries, together with close monitoring and reevaluation, particularly during volume replacement, is essential. Four cases are described which presented to the accident and emergency department of Glasgow Royal Infirmary, in three of which there was a significant delay in the diagnosis.     

Laser therapy accelerates initial attachment and subsequent behaviour of human oral fibroblasts cultured on titanium implant material. A scanning electron microscope and histomorphometric analysis

The aim of the study was to investigate the effect of low-level laser therapy (LLLT) on attachment and proliferation of human gingival fibroblasts (HGF) cultured on titanium implant material. HGF were exposed to gallium-aluminum-arsenide diode laser at dosages of 1.5 or 3 J/cm(2) and then cultured on commercially pure titanium discs. Cell profile areas were measured after 1, 3 and 24 h, using scanning electron microscopy and an automatic image analyzer. The results were expressed as percentage of attachment. In order to investigate the effect of LLLT on cellular growth after 8 and 10 days, HGF were cultured on titanium discs for 24 h and then exposed to laser irradiation on 3 consecutive days. Colony-forming efficiency (CFE) and clonal growth rates (CGR) were measured. Cell viability was determined by Hoechst and prodidium iodide staining. Non-lased cultures served as controls. Morphologically, the cells spread well on all titanium surfaces, indicating good attachment by both irradiated and non-irradiated cells. Fibroblasts exposed to laser irradiation had significantly higher percentages of cell attachment than the non-exposed cells (P<0.05). CFE and CGR were also enhanced for the irradiated cells (P<0.05). Cell viability was high (>90%) in the irradiated and control groups, without significant differences. It is concluded that in vitro LLLT enhances the attachment and proliferation of HGF on titanium implant material.