Metallic Nanoparticles: A Promising Arsenal against Antimicrobial Resistance-Unraveling Mechanisms and Enhancing Medication Efficacy.

The misuse of antibiotics and antimycotics accelerates the emergence of antimicrobial resistance, prompting the need for novel strategies to combat this global issue. Metallic nanoparticles have emerged as effective tools for combating various resistant microbes. Numerous studies have highlighted their potential in addressing antibiotic-resistant fungi and bacterial strains. Understanding the mechanisms of action of these nanoparticles, including iron-oxide, gold, zinc oxide, and silver is a central focus of research within the life science community. Various hypotheses have been proposed regarding how nanoparticles exert their effects. Some suggest direct targeting of microbial cell membranes, while others emphasize the release of ions from nanoparticles. The most compelling proposed antimicrobial mechanism of nanoparticles involves oxidative damage caused by nanoparticles-generated reactive oxygen species. This review aims to consolidate knowledge, discuss the properties and mechanisms of action of metallic nanoparticles, and underscore their potential as alternatives to enhance the efficacy of existing medications against infections caused by antimicrobial-resistant pathogens.

Bowman's layer transplantation in advanced keratoconus; 18-months outcomes.

PURPOSE: To assess the outcome of isolated Bowman's layer transplantation (BLT) in advanced keratoconus in the patients not suitable for ultra violet cross-linking and intra stromal corneal ring segments. STUDY DESIGN: Nonrandomized Quasi-Experimental. MATERIALS AND METHODS: Mid corneal stromal dissection followed by implantation of manually isolated bowman layer from a donor into the recipient stromal pocket was performed in the Department of Ophthalmology Khyber Teaching Hospital Peshawar from September 2018 to October 2018 and followed up over 18 months. RESULTS: Eleven eyes of 11 patients, 8 male and 3 female within the age range of 7-28 years with progressive keratoconus went under BLT All keratometry values decreased after surgery. Mean anterior pre-operative SimK changed from 69.05 ± 10.85 D to 61.14 ± 6.23 D at 18 months post-operatively (P = 0.005). Means pre-operative Kmax value decreased from 77.24 ± 7.58 D to 71.07 ± 5.37 D at 18 months post-operatively (p = 0.060). The mean pre-operative posterior keratometry value changed from - 10.03 ± 0.88 to - 8.96 ± 1.06 D at 18 months post-operatively (P = 0.002). Mean pre-operative thinnest corneal thickness increased from 281.64 ± 196.86 um to 355.27 ± 19.17 um at 18th months post-operatively (P = 0.001). Pachymetry p-value pre-operative to 18 months (P = 0.001) was statistically significant. Mean anterior SimK at 6 months post-operatively, 60.55 ± 5.56D changed to 61.14 ± 6.23D at 18 months post-operatively (P = 0.000), Kmax at 6 months postoperative 71.60 ± 5.01 D changed to 71.07 ± 5.37 D at 18 months post-operatively (P = 0.008). Both anterior K values at 6 months and 18 months post-operatively showed less significant change, and the same was true for Kmax data at 6 months and 18 months post-operatively. P-values at 6 months to 18 months post-operatively for cornea back data remained (P = 0.001) unchanged. No complications were observed intra-operatively or post-operatively. CONCLUSION: Bowman layer transplantation is a unique surgical treatment for advanced keratoconus to stabilize progressive ectasia with fewer complications avoiding the need for penetrating or deep anterior lamellar keratoplasty.

Passive removal of silicone oil through 23 gauge transconjunctival sutureless vitrectomy system.

OBJECTIVE: To study the outcomes of passive removal of silicone oil by 23 Gauge Transconjunctival Sutureless Vitrectomy System. METHODS: This prospective, consecutive case series study was conducted at Ophthalmology Department Unit I, Dow University of Health Sciences, Civil Hospital Karachi from January 2011 to December 2014. Only psuedophakic eyes with silicone oil temponade were selected. Main outcome measures were intra ocular pressure, time taken for removal of silicone oil, per operative and post operative complications. Pre and post operative IOP was compared by using two-tailed paired t-test and mean values with standard deviation were computed using difference of 95% confidence interval. Chi square test was applied for correlation of different variables. P-value of less than 0.05 was considered statistically significant. RESULTS: Out of 79 patients who underwent passive ROSO, 38 (48.1%) were males. Mean age of patients was 47.5±7.1 (sd) years. Mean time taken for passive ROSO was 7.31±2.41 (sd) minutes. Pre and post operative intra ocular pressure shows statistically significant (p=0.000) decrease in IOP. Retinal redetachment found in 13 (16.5%) cases during follow up period. CONCLUSION: Passive removal of silicone oil with 23 G suture less vitrectomy system is safe and effective in terms of less per operative and post operative complications. In this simple technique, there is less tissue trauma and little time consumed so it provides more comfort to patients and surgeons as well.

Impact of Duration of Macula off Rhegmatogenous Retinal Detachment on Visual Outcome.

OBJECTIVE: To assess impact of duration of macular detachment on visual outcome after scleral buckling for retinal detachment with macula off. METHODS: Prospective, descriptive case series was conducted at Ophthalmology Department Dow University of Health Sciences, Civil Hospital Karachi and Al Noor Eye Clinic Karachi from May 2012 to June 2013. Five groups were made according to period of macular detachment. Best corrected Visual acuity (BCVA) was main outcome measure. P value < 0.001 was considered significant. RESULTS: Mean duration of macula off was 17.0±4.0 (SD) days. Mean pre-operative VA in patients with immediate, early, intermediate, delayed or late group were 2/60, 2/60, Counting figure (CF) 3 meters (m), CF2 m and Hand Movement (HM) respectively. Only 48.48% patients of those repaired within 7 to15 days had significantly better (P < 0.001) BCVA (6/9-6/18) than the other groups. Only 19.35% patients of intermediate group achieved BCVA 6/18-6/24 (P < 0.001) which was comparatively better than the delayed and late group. CONCLUSIONS: Scleral buckle surgery for macular-off Rhegmatogenous Retinal Detachment has good post-operative visual outcomes if repaired within two weeks.

Solvent based fractional biosynthesis, phytochemical analysis, and biological activity of silver nanoparticles obtained from the extract of Salvia moorcroftiana.

Multi-drug resistant bacteria sometimes known as "superbugs" developed through overuse and misuse of antibiotics are determined to be sensitive to small concentrations of silver nanoparticles. Various methods and sources are under investigation for the safe and efficient synthesis of silver nanoparticles having effective antibacterial activity even at low concentrations. We used a medicinal plant named Salvia moorcroftiana to extract phytochemicals with antibacterial, antioxidant, and reducing properties. Three types of solvents; from polar to nonpolar, i.e., water, dimethyl sulfoxide (DMSO), and hexane, were used to extract the plant as a whole and as well as in fractions. The biosynthesized silver nanoparticles in all extracts (except hexane-based extract) were spherical, smaller than 20 nm, polydispersed (PDI ranging between 0.2 and 0.5), and stable with repulsive force of action (average zeta value = -18.55±1.17). The tested bacterial strains i.e., Klebsiella pneumoniae, Pseudomonas aeruginosa, Staphylococcus aureus, and Enterococcus faecalis were found to be sensitive to even small concentrations of Ag-NPs, especially P. aeruginosa. The antibacterial effect of these Ag-NPs was associated with their ability to generate reactive oxygen species. DMSO (in fraction) could efficiently extract antibacterial phytochemicals and showed activity against MDR bacteria (inhibition zone = 11-12 mm). Thus, the antibacterial activity of fractionated DMSO extract was comparable to that of Ag-NPs because it contained phytochemicals having solid antibacterial potential. Furthermore, Ag-NPs synthesized from this extract owned superior antibacterial activity. However, whole aqueous extract-based Ag-NPs MIC was least (7-32 µg/mL) as compared to others.

Reactive oxygen species induced oxidative damage to DNA, lipids, and proteins of antibiotic-resistant bacteria by plant-based silver nanoparticles.

This study assesses the mechanism of action of plant-based silver nanoparticles (AgNPs) against antibiotic-resistant bacteria. We compared AgNPs synthesized through Salvia moorcroftiana and Origanum vulgare extracts and their conjugates with the antibiotic Ceftriaxone for their capacity to cause oxidative damage through reactive oxygen species (ROS). We quantified ROS in the cells of two bacterial strains after treating them with all AgNP types and observed that AgNPs were most effective in K. pneumoniae as they resulted in the highest ChS1 count (44,675), while in P. aeruginosa, Cfx-AgNPs induced the highest levels of ROS with ChS1 count of 56,865. DNA analysis showed that both plant-based AgNPs (O-AgNPs = 0.192 and S-AgNPs = 0.152) were most effective in K. pneumoniae and S-AgNPs (abs = 0.174) and O-Cfx-AgNPs (abs = 0.261) in P. aeruginosa. We observed a significant increase in the levels of conjugated dienes (86.4 µM) and malondialdehyde (172.25 nM) in the bacterial strains after treatment with AgNPs, compared to the control (71.65 µM and 18.064 nM, respectively, in K. pneumoniae and P. aeruginosa). These results indicate lipid peroxidation. AgNPs also increased the levels of protein thiols (0.672 nM) compared to the control (0.441 nM) in K. pneumoniae, except for Chem-AgNPs (0.21 nM). These results suggest that plant-based AgNPs are more effective in oxidizing bacterial DNA, protein, and lipids than Chem-AgNPs. Furthermore, protein oxidation varied between AgNPs alone and AgNPs-antibiotic conjugates. The highest levels of protein thiols were found in the samples treated with O-Cfx-AgNPs (0.672 nM and 0.525 nM in K. pneumoniae and P. aeruginosa, respectively). The results demonstrated that AgNPs kill bacteria by altering bacterial macromolecules such as DNA, lipids, and proteins.

Pars plana surgical capsulotomy for posterior capsular opacification (PCO).

OBJECTIVE: To evaluate the safety and efficacy of pars plana surgical posterior capsulotomy in pseudophakic adults. METHODS: This prospective interventional case series was conducted at Sindh Govt Lyari General Hospital Karachi and Al- Noor Eye Hospital Karachi from June 2006 to May 2008. Complete ophthalmic examination of anterior and posterior segment was performed including assessment of type of posterior capsular opacification, measurement of intraocular pressure. Visual acuity, measurement of intraocular pressure and any unwanted complications were analyzed. RESULTS: Seventy six (43.18%) patients were operated on both eyes. Mean age was 62.01 +/- 13.02 years. There were 104 (59.1%) females and 72 (40.9%) males. Visual acuity at presentation was found to be 6/9 to 6/18 in 130 (59.1%)eyes, 6/18 to 6/60 in 81(36.8%) and below 6/60 in 9 (4.1%) eyes. A significant reduction in intraocular pressure (13.8, +/- 1.4, P = 0.000) was noted on second post operative day. Intraoperative complication included subconjuctival haemorrhage in 22 (10%) eyes, pin head haematoma at the entry site in 7 (3.2%) eyes, pea head haematoma at the entry site in 8 (3.6%) eyes, minor grade of vitreous haemorrhage in 9 (4.1%) cases. Insufficient capsular opening was noted in 8 (3.6%) eyes. Clinically evident macular oedema in 4 (1.8%) eyes. We found no case of endophthalmitis or retinal detachment. CONCLUSION: Surgical posterior capsulotomy is a safe and effective procedure in experienced hands and could be adopted in place of YAG laser.

Outcome of dual infusion through irrigating chopper in conventional phacoemulsification.

OBJECTIVE: To determine the operative advantage in terms of minimizing the complications following conventional phaco surgery with dual infusion through irrigating chopper. METHODS: A Randomized Controlled Clinical Trial (RCCT) was conducted in the Ophthalmology Unit-III, Sindh Government Lyari General Hospital and DUHS and Al-Noor Eye Hospital Karachi, from March 2008 to February 2009. A total of 200 eyes with nuclear/cortico-nuclear cataract on Lens Opacity Classification System III underwent phacoemulsification. In all 100 eyes in group A were randomized to have conventional phacoemulsification with dual infusion technique through irrigating chopper and another 100 eyes in group B by conventional phaco surgery. Outcomes in two groups were judged by amount of Ringer's Lactate used, stability of anterior chamber and number of complications observed. RESULTS: Rate of intra-operative complications was lower in group A as compared to group B (p=0.002). Anterior chamber depth was maintained in all cases of group A while it collapsed in 9 cases of group B which was highly significant (p=0.003). Mean amount of Ringer's Lactate used in group A was 260.2 +/- 55.07 ml and 195.8 +/- 35.0 ml in group B, which was significantly high (p<0.001). CONCLUSION: Dual infusion through irrigating chopper serves triple function of irrigation, chopping and additional separate distant infusion. It improves anterior chamber stability and compensates surge and operative advantage to surgeon.

Mechanistic aspects of plant-based silver nanoparticles against multi-drug resistant bacteria.

Resistance among pathogenic bacteria to the existing antibiotics is one of the most alarming problems of the modern world. Alongwith reducing the use of antibiotics, and antibiotic stewardship, an alternative to antibiotics is much needed in the current scenario to combact infectious diseases. One alternative is to produce nanomaterials, especially, silver nanoparticles (AgNPs) against antibiotic-resistant bacteria. AgNPs are the most vital and fascinating nanoparticles because of their unique structural and functional properties and application against pathogenic bacteria. However, the synthesis of AgNPs remains a problem because of the chemicals and energy requirements and the byproducts of the reactions. Concerns have been raised about using chemically and physically synthesized nanoparticles because of their potential risks to the human body, animals, and environment. Green synthesis of these nanoparticles is a better alternative to physical and chemical approaches. Plant-based synthesis in turn is a method which can provide AgNPs that are cost-effective and eco-friendly as well as biocompatible. The specific features of size, morphology and shape of plant-based AgNPs give them the potency to fight multi-drug resistant bacteria. A detailed look into mechanistic aspects of the action of AgNPs against resistant bacteria with a focus on characteristic properties of AgNPs is required. This review discusses in detail these aspects and the potential of plant-based AgNPs as a solution to antibiotic resistance.

Comparison of conventional phacoemulsification technique vs. cool phacoemulsification technique with the importance of phacoemulsification variables.

OBJECTIVE: To compare the efficacy and outcome after cool phacoemulsification with conventional phacoemulsification techniques in terms of effective phacoemulsification time (EPT), wound size and operative complications along with other variables used for the technique. STUDY DESIGN: Randomized controlled clinical trial (RCCT). PLACE AND DURATION OF STUDY: Ophthalmology Unit III, Sindh Government Lyari General Hospital and DUHS and Al-Noor Eye Hospital, Karachi, from January to December 2008. METHODOLOGY: One hundred eyes with nuclear/cortico-nuclear cataract on LOCS III (Lens Opacities Classification System III) underwent phacoemulsification. Fifty eyes were randomized to have surgery by standard phacoemulsification technique and the other 50 eyes by cool phacoemulsification technique. Efficacy and outcomes were judged in terms of variables like effective phaco time, vacuum and power used, quantity of Ringer's lactate solution used and corneal burn. The results between the two groups were compared. RESULTS: Among the phaco variables, the vacuum used in all cases ranged from 100 to 200 mmHg in group A with mean vacuum of 145.3+29.6 and 300 to 350 mmHg with mean value of 325.8+14.5 in group B at phaco II (p < 0.001). There was a significant difference in amount of Ringer's lactate used during surgery with 100-180 ml in conventional phacotechnique as opposed to 75-150 ml in cool phacoemulsification (p < 0.001). EPT in group A was between 30 to 180 seconds with mean of 111.3+40.4 seconds while in group B, it ranged between 2 to 12 seconds with mean of 6.1+2.92 seconds (p < 0.001). Rate of intra operative complications was lower in cool phacoemulsification (2%) as compared with conventional technique (18%, p=0.008). CONCLUSION: Cool phacoemulsification is a safe technique to operate cataract of all grades. It seems to be superior as it reduces effective phaco time, less operative and postoperative complications and is, therefore, safer for the cornea especially with regard to corneal wound burn. However, significantly greater amount of vacuum is needed.

Management of cataract with macular oedema due to diabetes mellitus type-II and hypertension with grid laser prior to surgery and intra-vitreal bevacizumab (Avastin) peroperatively.

OBJECTIVE: To study the visual outcome in patients subjected to cataract extraction with prior grid laser and intraoperative intravitreal bevacizumab injection. METHODS: This prospective case series comprised of 38 patients subjected to phacoemulsification and in the bag intraocular lens implantation at Al-Noor Eye Hospital and Sindh Govt Lyari General Hospital Karachi from January 2007 to December 2008. All the patients had prior macular grid treatment and intra-operative injection of intra-vitreal Avastin. Diabetes mellitus duration, preoperative glycosylated haemoglobin (HbA1c) level and other systemic and local complications of diabetes were recorded. The patients were clinically assessed with biomicroscopic examination preoperatively, and postoperatively on day 1, week 1, and in months 1, 2, 3 and 6 respectively. Visual acuity and state of macular oedema was clinically assessed and documented. RESULTS: Out of thirty-eight patients, eighteen were males and 20 were females. Mean duration of diabetes was 9.92 +/- 5.5 years (Range 4-16) while that of hypertension was 7.87 +/- 3.66 years (Range = 2-15). HbAlc level was 8.36% +/- 1.93% (range 6.3 - 12.3). Thirty-one (81.5%) patients had HbA1c level 8.0% or above indicating a poor control. At 6 months of follow up best corrected distant visual acuity of 6/6 to 6/9 was achieved in 23(60.5 %), 6/12 in 11(28.9%) and 6/24 in 4(10.5%) cases while best corrected near acuity of N/6 was achieved in 22 (57.8%) N/8 in 12 (31.4%) and N/12 in 4 (10.5%) cases. At 6 months follow up visual acuity declined in two cases because of uncontrolled diabetes and hypertension. CONCLUSION: Cataract surgery in diabetic patients with macular oedema and hypertension has a good visual outcome if prior macular grid laser is performed and intra-vitreal anti VEGF is injected during surgery.

Frequency of retinopathy in newly diagnosed type 2 diabetes patients.

OBJECTIVE: To determine the frequency of retinopathy in newly diagnosed type 2 diabetes patients. METHODS: A cross sectional study was conducted on 130 consecutive newly diagnosed diabetes patients who received out patient care at the diabetes clinic of Dow University of Health Sciences (DUHS) and one private diabetic clinic from June 2006 to December 2006. Patients who were 25 years or older and recently diagnosed as type 2 diabetics, were included in the study. Patients who had type I diabetes, andwere already on diabetic medication were excluded from the study. Every patient underwent a detailed eye examination. Diabetic retinopathy was diagnosed on the basis of presence of lesions like microaneurysms, clinically significant macular oedema (CSMO), dull foveal reflex, venous beading and occasional dot blot haemorrhages. RESULTS: The study comprised of 130 patients with a mean age 43.2 +/- 10.2 years, 66.9% of the patients were males. Overall, 15% (95% CI 14.7, 15.3) patients were found to have diabetic retinopathy within two months of diagnosis of type 2 diabetes mellitus. CONCLUSION: The frequency of retinopathy in newly diagnosed type 2 diabetes mellitus patients was high in this study. This underlines the importance of detailed ophthalmic examination of all patients of type 2 diabetes mellitus at the time of diagnosis.

Combined phacoemulsification, vitrectomy and endolaser photocoagulation in patients with diabetic retinopathy and cataract.

OBJECTIVE: To determine the outcomes of early vitrectomy and endolaser photocoagulation effects during phacoemulsification in cataractous eyes with diabetic retinopathy. STUDY DESIGN: Descriptive study. PLACE AND DURATION OF STUDY: Ophthalmology Department Unit-II, DUHS, Civil Hospital, Karachi, and Al-Noor Eye Clinic, Karachi, from February 2009 to December 2010. METHODOLOGY: Consecutive 54 patients with 7-15 years duration of type II diabetes with severe non-proliferative diabetic retinopathy (NPDR) and early proliferative diabetic retinopathy (PDR) who had cataract grade I and II underwent vitrectomy, endolaser photocoagulation and phacoemulsification with IOL implantation. Best corrected visual acuity was main outcomes measure assessed till 6 months follow-up. RESULTS: Out of 54 eyes, 32 patients were females and 22 were males. Majority 47 (87%) eyes gained significant (p<0.001) improvement of best corrected visual acuity of four lines or better while 5 (9.3%) eyes retained stable visual acuity. In only 2 eyes, vision declined to 3/60 or less. CONCLUSION: Early vitrectomy with phacoemulsification in severe NPDR and early PDR patients, if assisted or augmented with endolaser photocoagulation, maximizes, early visual rehabilitation with less morbidity and may retard progression of retinopathy.

Early phacoemulsification in diabetic cataract for early recognition and management of diabetic macular oedema.

OBJECTIVE: To get optimal visualization of fundus by early phacoemulsification in diabetic cataract for early recognition and management of diabetic macular oedema. STUDY DESIGN: Interventional study. PLACE AND DURATION OF STUDY: Ophthalmology Unit III, Sindh Government Lyari General Hospital and Dow University of Health Sciences and Al-Noor Eye Hospital, Karachi, from July 2008 to June 2009. METHODOLOGY: Patients with uncontrolled type-II diabetes mellitus of more than 10 years of duration were selected. Patients with clinical significant macular oedema (CSME), non-proliferative diabetic retinopathy (NPDR) and proliferative diabetic retinopathy (PDR) were excluded. Follow-up was done on day 1, 1 week, 1 month, 3 months and 6 months. RESULTS: The male to female ratio was 1:1.44. Out of 218 patients; 129 (59.2%) were males and 89 (40.8%) were females. CSME was found in 82 patients (37.6%) at first postoperative week which declined to 29 cases (13.3%) at first month follow-up. Three subjects developed mild to moderate NPDR. In majority of the subjects, best corrected visual acuity (BCVA) gradually improved in each subsequent follow-up visit. CONCLUSION: Early phacoemulsification in diabetic cataract offers optimal posterior pole visualization and clears the ambiguity of decreased vision either caused by cataract or macular oedema. Uncomplicated phacoemulsification does not accelerate diabetic macular oedema or retinopathy provided glycemic control and co-morbids are well addressed.

Posterior assisted levitation (PAL) by using Akahoshi/Wahab irrigating pars plana levitator.

OBJECTIVE: To assess the outcome of irrigating Akahoshi/Wahab pars plana levitator for posterior assisted levitation in dropped nucleus during phacoemulsification. STUDY DESIGN: A case series. PLACE AND DURATION OF STUDY: Ophthalmology Unit-III, Dow University of Health Sciences at Sindh Government Lyari General Hospital and Al-Noor Eye Hospital, Karachi, from January 2008 to December 2009. METHODOLOGY: Cases of dropped nucleus during phacoemulsification were recruited. Predisposing factors and stage of phacoemulsification at which dropped nucleus were recognized. Levitator was inserted through pars plana after vitrectomy around nucleus and levitation was carried out. Follow-up was done till 6 months. RESULTS: Thirty two patients including 18 males (56.3%) and 14 females (43.8%) underwent pars plana levitation. Predisposing factors were pupillary miosis in 9 cases, Brunescent cataract in 7 cases, pseudoexfoliation in another 7 cases, hypermature cataract in 5 cases and extended capsulorrhexis in 4 cases. Posterior capsular rent occurred in 22 (68.8%) cases while zonular dehiscence / rupture were found in 10 cases (31.3%). Nuclei were dropped during quadrant aspiration in 10 cases (31.3%) and during chopping in 8 cases (25%). Another 5 cases (15.6%) occurred during each hydrodissection and chopping while 4 cases (12.5%) were found during sculpting of nuclei. Final best corrected visual acuity was 6/12 and better in 22 cases (68.8%) while in 10 cases (31.3%) it was 6/18 to 6/36. No complication related to pars plana levitator was observed. CONCLUSION: Posterior assisted levitation of dropped nucleus during phacoemulsification by irrigating Akahoshi/Wahab pars plana levitator is a fast and safe surgical technique.