Study on lower urinary tract infections and stent colonization in patients with double- J ureteral stents in a Tertiary care hospital.

Double-J ureteral stents represent a minimally invasive alternative to preserve urinary drainage whenever ureteral patency is deteriorated or is under a significant risk to be occluded due to extrinsic or intrinsic etiologies. Like all synthetic medical intracavitary devices, Double-J ureteral stent also offers a suitable surface for microbial colonization by biofilm forming microorganisms. Recognizing the colonization is very important for prevention of bacteremia during manipulation As microbial ureteral stent colonization does not necessarily lead to bacteriuria, negative urine culture does not rule out biofilm formation, hence urine culture has a low predictive value for ureteral stent colonizatio

Investigation of waterborne cadmium toxicity in the green-lipped mussel, Perna canaliculus using biomarkers – a potential bioindicator of coastal metal pollution in New Zealand

Coastal metal pollution is a major concern to the health and well-being of aquatic organisms. Bioindicator organisms such as mussels have the potential to monitor coastal metal pollution. In New Zealand, the feasibility of employing green-lipped mussels, Perna canaliculus as a bioindicator species is yet to be investigated. This thesis focuses on applying a suite of biomarkers on green-lipped mussels exposed to cadmium (Cd) to evaluate the utility of the biomarkers and investigate the utility of the mussels in assessment of metal pollution. Cd is a non-essential metal and is known to be highly toxic to many aquatic organisms. This research consisted of a laboratory study to understand the mechanistic effects of Cd toxicity in green-lipped mussels. Physiological, biochemical, immunocytotoxic and cytogenotoxic biomarker responses were measured in mussels exposed to acute (96 h; 2000 µg L⁻¹ and 4000 µg L⁻¹) and subchronic (28 d; 200 µg L⁻¹ and 2000 µg L⁻¹) Cd treatments. The 96 h LC₅₀ value for P. canaliculus was 8160 µg L⁻¹, indicating that the green-lipped mussels were relatively tolerant to Cd exposure. Results from the Cd exposures, indicated that Cd had a negative impact on physiological processes such as feeding and oxygen consumption. Cd-induced physiological impairments caused an imbalance between energy gain and energy loss in the mussels that led to negative scope for growth. Detoxification (metallothionein-like protein) and defence mechanisms (catalase) were induced in the mussels to provide protection against the toxic effects of Cd. However, the defence mechanisms were not sufficient to protect the mussels from damage due to lipid peroxidation. DNA damage was also observed in the haemocytes of mussels as a result of Cd exposure. Cellular homeostasis (alkaline phosphatase) mechanisms were also perturbed. The immunocytotoxic endpoints reflected differences in haemocyte proportions in the haemolymph of Cd-exposed mussels. Exposure to Cd also led to the formation of several nuclear aberrations in the gill cells of mussels. Overall the laboratory study highlighted toxic effects of Cd on green-lipped mussels that were dependent on the dose and/or the duration of exposure to Cd. Among the biomarkers tested, clearance rate, metallothionein-like protein induction and the formation of nuclear aberrations in mussel gill cells correlated strongly to Cd accumulation levels and reflected Cd exposure effects. The feasibility of employing green-lipped mussels as bioindicators was tested during the field study. Green-lipped mussels were collected from different coastal sites along the South Island in NZ. Metal concentrations in the sediment and in four different mussel tissues were analysed. The findings indicated a significant geographical difference in metal concentration in the environment and in the metal accumulation levels in the mussels. Overall, the field study indicated that the green-lipped mussel, Perna canaliculus has the potential to be used as a bioindicator species for assessment of coastal metal pollution levels in NZ

Acute Toxicity of Metals: Cu, Pb, Cd, Hg and Zn on Marine Molluscs, <i style="">Cerithedia cingulata</i> G., and <i style="">Modiolus philippinarum </i>H.

141-145Present study was intended to compare the acute static renewal toxicity tests on marine snail, Cerithidae cingulata and bivalve, Modiolus philippinarum that were performed with Cu, Cd, Pb, Zn and Hg. The 96 h LC50 values for C.cingulata were 0.521, 9.193, 15.507, 8.990 and 0.053 mg.l-1 and the 96 h LC50 values for M.philippinarum were 0.023, 0.221, 2.876, 2.337 and 0.007 mg.l-1 in respective metals. This study indicated that mercury was highly toxic to both C.cingulata and M.philippinarum. While lead was resistant metal to both marine molluscs tested. Order of increasing toxicity of metals to C.cingulata was Hg > Cu > Zn> Cd > Pd and to M.philippinarum was Hg > Cu > Cd > Zn > Pb. Safe level concentrations for all 5 metals were also calculated. The LC50 values of the present study may be useful in deriving marine water quality standards in the coastal waters of Gulf of Mannar