Validation of QuEChERS analytical technique for organochlorines and synthetic pyrethroids in fruits and vegetables using GC-ECD.

In the present day scenario of increasing awareness and concern about the pesticides, it is very important to ensure the quality of data being generated in pesticide residue analysis. To impart confidence in the products, terms like quality assurance and quality control are used as an integral part of quality management. In order to ensure better quality of results in pesticide residue analysis, validation of analytical methods to be used is extremely important. Keeping in view the importance of validation of method, the validation of QuEChERS (quick, easy, cheap, effective, rugged, and safe) a multiresidue method for extraction of 13 organochlorines and seven synthetic pyrethroids in fruits and vegetables followed by GC ECD for quantification was done so as to use this method for analysis of samples received in the laboratory. The method has been validated as per the Guidelines issued by SANCO (French words Sante for Health and Consommateurs for Consumers) in accordance with their document SANCO/XXXX/2013. Various parameters analyzed, viz., linearity, specificity, repeatability, reproducibility, and ruggedness were found to have acceptable values with a per cent RSD of less than 10%. Limit of quantification (LOQ) for the organochlorines was established to be 0.01 and 0.05 mg kg-1 for the synthetic pyrethroids. The uncertainty of the measurement (MU) for all these compounds ranged between 1 and 10%. The matrix-match calibration was used to compensate the matrix effect on the quantification of the compounds. The overall recovery of the method ranged between 80 and 120%. These results demonstrate the applicability and acceptability of this method in routine estimation of pesticide residues of these 20 pesticides in the fruits and vegetables by the laboratory.

5-Fluoro-Uracil and Low Molecular Weight Heparin in the Management of Proliferative Vitreo-retinopathy.

BACKGROUND: Proliferative vitreo-retinopathy (PVR) is the most common cause of failed repair of a primary rhegmatogenous retinal detachment (RRD). The success rates for the surgery of complicated RRD has doubled with improved vitreous techniques from 35-40% to approximately 65-75% at six months. However, despite these advances, recurrent vitreo-retinal traction leads to re-detachment in more than one-fourths of the initially successful cases. The use of adjunctive treatments to prevent cellular proliferation holds promise for the prevention of PVR or recurrences after surgery. One focus has been on the use of intra-vitreal antimetabolites to prevent the occurrence of PVR. METHODS: Thirty patients of complicated retinal detachment associated with PVR, C1 or more were managed by vitreo-retinal (VR) surgery with the addition of 250 µg / ml of 5-fluorouracil (5FU) and 1 IU / ml of low molecular weight heparin (LMWH) to the vitreous infusion. The patients were examined for any evidence of PVR till 180 days as also for any systemic or other ophthalmic complication. RESULT: Out of the 30 cases in the study group, 25 (83.34%) cases had retinal settlement at the end of six weeks, which is similar to the outcomes of conventional VR surgery. There was no case of any serious complication. CONCLUSION: The addition of LMWH and 5FU did not enhance the outcome of VR surgery.

Evaluation of Vitreous Substitutes in Managing Complicated Vitreo-retinal Surgeries.

BACKGROUND: Vitreous substitutes presently in use for intraoperative tamponade are perfluorocarbon liquids (PFCL) and for post operative tamponade are silicon oil (SO), sulphur hexafluoride (SF6) and perfluorocarbon gas (PFC). Several factors are important for a thorough understanding of each of these vitreous substitutes. The absorption or necessity for removal, indications for use (including clinical studies and special surgical methods), additives and complications of use have to be considered. METHODS: Three port standard pars plana vitrectomy was performed in 60 consecutive cases requiring intra-vitreal intervention. PFCL was used intra-operatively in 30 cases (PFCL group and X group). The eyes were implanted with SO (silicon oil subgroup), PFC (C3F8 sub-group) and SF6 (SF6 sub-group) in twenty cases each. Apart from best corrected visual acuity (BCVA), the retinal status and the longevity of gas when used, changes and reaction in both the anterior and posterior segments were noted. RESULT: The difference of postoperative BCVA in the PFCL and non-PFCL groups was statistically significant with p < 0.001. In both the PFCL and non-PFCL groups the difference between preoperative and postoperative BCVA was statistically significant with p < 0.0001. All three vitreous substitutes studied are effective given the case where they had been utilised. CONCLUSION: PFCL is invaluable in the management of complicated retinal detachment (RD). Where a vitreous microsurgery is indicated, the visual outcome is good. SF6 is useful for short-term tamponade. Silicon oil and C3F8 are useful for longer tamponade.

Primary 360° Broad Buckling in Retinal Detachment.

BACKGROUND: Chronic rhegmatogenous retinal detachment behaves like proliferative vitreo-retinopathy (PVR) even without evidence of the same. Surgery could be done either with conventional buckling procedures where the extent of buckling is determined by the number and location of the breaks or by primary vitreous surgery. In this study these cases were managed with primary 360°encircling broad buckle without a vitreous procedure. METHODS: 210 eyes, with rhegmatogenous retinal detachment of more than six months duration and with PVR up to C3 (CP3 focal) were subjected to buckling surgery. Trans-scleral cryopexy of the breaks, 360°encircling buckle with a 276 - 279 tire and subretinal fluid drainage was performed. RESULT: Most (85.74%) of the eyes showed anatomical retinal re-attachment. CONCLUSION: Primary broad encircling buckling can be conducted successfully in cases of long standing retinal detachment.

Management of Nucleus and IOL Drop.

BACKGROUND: Thirty six cases of lenticular nucleus drop following phacoemulsification and 43 cases of posterior dislocation of intraocular lens (IOL) inclusive of two paediatric cases were managed by a modified vitrectomy procedure without using perfluorocarbon liquid (PFCL). METHODS: In these cases the incision was placed inferotemporally at pars plana. The limbal sites of the earlier cataract surgery were utilised as the other two ports. In either case adequate vitrectomy was performed first. In cases of nuclear drop, the nucleus was impaled (speared) with a micro vitreo retinal blade and brought into the anterior chamber from where it was delivered out. In cases of IOL drop the same was picked up by an intra-vitreal forceps. RESULT: Of the 77 adult cases treated 57 (74%) of the eyes had a visual recovery of 6/18 or more. CONCLUSION: Prompt surgical management in cases of nuclear drop or posterior dislocation of IOL yields good results.

Intravitreal dexamethasone implant versus triamcinolone acetonide for macular oedema of central retinal vein occlusion: quantifying efficacy and safety.

PURPOSE: Among the retinal vascular diseases, burden of retinal vein occlusion is most common immediately after diabetic retinopathy. Intravitreal corticosteroids are gaining popularity in managing macular edema (ME) of RVO. Our study compares efficacy and safety of intravitreal triamcinolone (IVTA) and dexamethasone implant (IVD) over 6 months. METHODS: This comparative, prospective, randomized study on 40 patients of non-ischemic central RVO with significant ME (> 330 µm) of < 3 months duration. Study was done at Army Research Hospital between Sep-2012 and May-2014 in accordance to Helsinki Declaration. IVD group (n = 20) received Ozurdex® while IVTA group (n = 20) received triamcinolone-acetonide (4 mg/0.1 ml), followed up at day-1 and weeks 4, 8, 12, 24. RESULTS: At 6 months, mean improvement in best corrected visual acuity and retinal thickness (CMT) in the IVD group was 0.43 logmar and 323 µm and in IVTA group was 0.49 logmar and 322 µm respectively. Proportion of patients achieving ≥ 15 letters was about 40% in both groups. IOP rise was significantly higher in IVTA group at 12 and 24 weeks. In IVTA group ≥ 10 mmHg IOP rise was seen in 60% of patients, 41.6% among them had > 35 mmHg and 66% needed combination treatment and failed to reach baseline line IOP at 6 months. In IVD group, 5 pts had IOP rise with all being < 26 mmHg and were easily managed with single agent with IOP reaching baseline by 6th month in all pts. Relative risk of IOP rise with IVTA is 2.4 times higher compared to IVD. Cataract progression and cataract surgeries were required at significantly higher rates in IVTA group. In IVTA group, cataract progression was seen in 35% patients, with 71.5% requiring cataract surgery at 6 months. IVD group, 10% patients had cataract progression while none required surgery at 6 months. Relative risk of cataract progression with IVTA is 3.5 times higher compared to IVD. CONCLUSION: Intravitreal steroids are effective in managing macular edema of retinal vein occlusion, while newer formulation of sustained release dexamethasone implant is significantly safer than IVTA.

Dissipation kinetics of spiromesifen on tea (Camellia sinensis) under tropical conditions.

Spiromesifen (Oberon) is a new insecticide and miticide of chemical class ketoenol active against white flies (Bemisia spp., Trialeuroides spp.) and spider mites (Tetranychus and Panonychus spp.). Due to its potential significance in insect resistance management, it is important to establish its behaviour on crop and environment. In the present study, the degradation/dissipation of spiromesifen on tea crop under tropical environmental conditions was studied and its DT(50) (t(1/2)), and DT(90) (time to reduce to 90% of the initial value) were estimated. Spiromesifen was sprayed on tea crop after first rain flush at four different locations @ 96 and 192ga.i.ha(-1). Samples of tea leaves were drawn at 0, 1, 3, 5, 7, 10, 15, 21 and 30 days after treatment and that of soil at 10 days after treatment and at harvest from 0 to 15 and 15 to 30cm layers. After crude extraction of tea leaves for spiromesifen residues with acetone:water, the contents were partitioned with cyclohexane:ethyl acetate and cleaned up on Florosil column. Soil residues were also extracted similarly. Quantification of residues was done on GC-MS in Selected Ion Monitoring (SIM) mode in mass range 271-274m/z. The LOQ of this method was found to be 0.05microgg(-1) while LOD being 0.015microgg(-1). The DT(50) of spiromesifen when applied at recommended doses in tea leaves was found to be 5.0-8.5 days. Ninety-nine percent degradation was found to occur within 33-57 days after application. In soil, no residues of spiromesifen were detectable 10 days after treatment.

Insecticide interaction with carrier and neuroproteins.

Binding of alpha-, beta-, gamma-hexachlorocyclohexane, p,p'-DDT and p,p'-DDE with bovine serum albumin (BSA) and locust brain homogenate was studied. Binding affinities of pesticides were higher for the locust brain homogenates than for BSA. Results of uptake by isolated locust brain revealed higher uptake of gamma-HCH than alpha-HCH. gamma-HCH uptake was also higher from locust haemolymph than either from BSA or from buffer.

Comparative role of proteins in transport of HCH-isomers in desert locust, Schistocerca gregaria Forskal and bovines.

The studies on binding of hexachlorocyclohexane (HCH) with carrier proteins were carried out to establish the role of proteins in the transport of insecticides in insects. Sephadex G-200 column chromatography resolved haemolymph of adult male desert locust, Schistocerca gregaria into three major protein peaks. There was significant binding of gamma-HCH with first protein peak (F1). Two classes of binding sites were observed on first protein peak for gamma-HCH. However low level of binding was observed with the third protein peak (F3) of the haemolymph. Bindings of HCH-isomers (alpha, beta and gamma) with bovine serum albumin (BSA) were not related to their water solubilities. Moderate to low affinities (1.4 -1.84 x 10(6) M(-1)) of HCH-isomers for BSA were observed. The present studies showed that more HCH binds to haemolymph lipoprotein of locust as compared to BSA. This indicates a significant role of haemolymph proteins in the transport of insecticides in insects.

Isolation and characterization of the haemolymph lipoprotein of desert locust, Schistocerca gregaria Forskal.

A yellow lipoprotein was isolated and purified from haemolymph of desert locust, Schistocerca gregaria Forskal, by precipitation at low ionic concentration and by gel filtration. Sephadex G-200 resolved haemolymph into five protein peaks. First peak was of lipoprotein with molecular weight of 501,000 +/- 7000 (n = 3) and on electrophoresis, it separated into three bands. Maximum lipids from lipoprotein could be extracted with chloroform: methanol solvent system and were 52% by weight.

Dissipation kinetics of trifloxystrobin and tebuconazole on apple (Malus domestica) and soil--a multi location study from north western Himalayan region.

A new combinational fungicide formulation trifloxystrobin 25%+tebuconazole 50% (Nativo 75WG), introduced as a part of resistance management strategy, was studied for dissipation behaviour on apple fruits. Nativo 75WG was sprayed twice at the rate of 400 g and 800 g a.i. ha(-1) equal to trifloxystrobin application rate of 100 and 200 g a.i. ha(-1) and tebuconazole at application rate of 200 and 400 g a.i. ha(-1) at four different locations in the Northwest Himalayan region of India. The fruit samples collected at 10d interval and soil samples taken at harvest time were analyzed after second spray. The residual concentrations of trifloxystrobin, its acid metabolite CGA 321113 and tebuconazole were measured. Residues of both fungicides were determined by using gas chromatograph, Agilent 6890N having electron capture detector. The mean initial deposits of trifloxystrobin at four locations were found to be in the range of 0.333-0.387 mg kg(-1) and 0.512-0.714 mg kg(-1) at the application rate of 100 and 200 g a.i. ha(-1), and half-life were found between 19.38-24.93 d and 19.84-28.86 d at the respective doses. The Σ-trifloxystrobin and tebuconazole residues were below determination limit in 40 d apple fruits and soil samples. Initial deposits of trifloxystrobin and tebuconazole were below their Codex MRLs at the respective single doses. The half life value of the tebuconazole deposits ranged between 19.38-25.99 d and 19.84-28.86 d at the respective single and double dose. The study thus suggests 1d pre harvest interval for safe consumption of apple fruit after the application of Nativo 75 WG at single dose.

Pleomorphic adenoma of a subconjunctival ectopic lacrimal gland.

This report describes a case of pleomorphic adenoma of an ectopic lacrimal gland arising subconjunctivally in the lateral fornix in a 13-year-old girl. The tumor was removed surgically in toto with the capsule. This is probably the first reported case.

Persistence and dissipation kinetics of spiromesifen in chili and cotton.

In a field study carried out at three different locations, the dissipation of spiromesifen on cotton and chili was studied and its DT50, and DT99 were estimated at each location. Spiromesifen was sprayed on chili at 96 and 192 g a.i. ha(-1) and cotton at 120 and 240 g a.i. ha(-1). Samples of chili fruits were drawn at 0, 1, 3, 5, 7, 10, 15, 21, 30 days after treatment and that of cotton seed and lint at first picking and harvest. Soil samples were drawn 30 days after treatment from 0 to 15 and 15 to 30 cm layer. Quantification of residues was done on GC-MS in Selected Ion Monitoring (SIM) mode in mass range 271-274 m/z. The LOQ of this method was found 0.033 microg g(-1), LOD being 0.01 microg g(-1). The DT50 of spiromesifen when applied at recommended doses in chili fruits was found to be 2.18-2.40 days. Ninety-nine percent degradation was found to occur within 14.5-16.3 days after application. Residues of spiromesifen were not detected in cotton seed and lint samples at the first picking. In soil, no residues of spiromesifen were detectable 15 days after treatment.