Polyvinyl Alcohol-iodine Research Articles

Evaluation of anti-adenoviral effects of the polyvinyl alcohol iodine ophthalmic solution.

To investigate the virucidal effects of a polyvinyl alcohol iodine, Saniode, against 16 types of human mastadenovirus (HAdV) causing ophthalmic, respiratory, gastrointestinal, urinary, and systemic infections. Laboratory investigation METHODS: Fifty microliters of Saniode were exposed to 10 μL each containing HAdV virus stock solution of 1 × 106copies/μL of HAdV-1, -2, -3, -4, 5, -6, -7, -8, -11, -37, -53, -54, -56, -64, -81, and -85 for 10 s, 30 s, 1 min, and 3 min. After neutralization with 0.5% sodium thiosulfate, the mixture was diluted by ten-fold serial dilution and inoculated into 24 wells containing confluent A549 cell monolayers. Virucidal effects were calculated relative to the positive control on days 7-10 and observed until 30 days post-infection. Saniode satisfied the EN-14476 criterion for virucidal effects (>99.99%) for all HAdV types at all exposure times, including at 10s on days 7 to 10 post-infection. All types of HAdVs that reacted for > 1 min achieved 99.99% reduction, including after 30 days. Saniode displayed virucidal effects against all tested HAdV types. Currently, with no specific medication available for HAdVs in ocular infection, this could be an option to prevent the spread of keratoconjunctivitis.

Integrated photo-inspired antibacterial polyvinyl alcohol/carboxymethyl cellulose hydrogel dressings for pH real-time monitoring and accelerated wound healing

Recurrent infection of chronic wounds remains a major clinical challenge. Recently, the hydrogel antibacterial materials have attracted extensive attention for preventing infection in wound healing. In this study, a hybrid hydrogel made of polyvinyl alcohol - iodine (PAI), sodium carboxymethyl cellulose (CMC), and carbamino quantum dot (CQDs) was prepared by the cross-linking of hydrogen bonds, named as polyvinyl alcohol‑iodine/sodium carboxymethyl cellulose/carbon quantum dots (PAI/CMC/CQDs). The composite hydrogels exhibited the outstanding photothermal conversion efficiency with near infrared (NIR) light irradiation, and the high antibacterial activity against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli). Meanwhile, the elevated temperature of the composite hydrogels up to ∼45 °C was able to stimulate the migration of epidermal cell to accelerate skin repair. Given that PAI and CQDs could respond to different pH values (5–8), the real-time would pH information was provided by the visible light and fluorescent light dual monitoring system by naked eye. Moreover, the visible-fluorescent images could be collected and transformed into RGB signals to quantify the would pH levels, avoiding secondary injuries caused by frequent dressing changes. PAI/CMC/CQDs was demonstrated the significant therapeutic effect on chronic wounds by eliminating bacterial infections and promoting skin repair under the smart RGB monitoring system.

Treatment trials for viral conjunctivitis: what we have learned and how we can improve.

Treatment trials for viral conjunctivitis: what we have learned and how we can improve.

Microscale assessment of iodate fortificant in food-grade salt using the potassium iodide/polyvinyl alcohol colorimetric reagent

A rapid and straightforward spectrophotometric measurement of iodate in food-grade sodium chloride was developed based on the formation of a purple-red polyvinyl alcohol-iodine complex monitored at 490 nm. The conditions that influence the colorimetric reactions were optimized using a univariate approach. The method exhibited optimum results using 2% polyvinyl alcohol, 10 mM KI, and 0.5 M phosphoric acid. A matrix-matched calibration curve was prepared to eliminate interference due to the presence of NaCl and to provide a direct reading of iodate concentration in salt from the absorbance reading. Under optimum conditions, a linear calibration plot was observed from 5 to 140 mg iodate per kilogram (r = 0.9931). The method exhibited a sensitivity of 6.8 × 10−3 (mg iodate per kg of salt)−1 with a detection limit of 0.61 mg kg−1. The method was applied in actual samples, and the results agreed well with the titration method at a 95% confidence level using a paired t-test. The method supports the green analytical method as evaluated using Green Analytical Procedure Index (GAPI) and Analytical Eco-scale.

Topical pharmacologic interventions versus placebo for epidemic keratoconjunctivitis.

Topical pharmacologic interventions versus placebo for epidemic keratoconjunctivitis.

Corynebacterium ocular infection after Baerveldt glaucoma implant surgery: treatment involving immediate tube withdrawal and temporary subconjunctival tube placement: a case report

BackgroundWe report a case of Corynebacterium endophthalmitis secondary to tube exposure following Baerveldt glaucoma implant surgery that was successfully treated with prompt tube withdrawal and temporary subconjunctival tube placement without removing the glaucoma drainage device.Case presentationA 65-year-old Japanese man with secondary glaucoma underwent glaucoma drainage device surgery with a donor scleral patch graft in the inferonasal quadrant of his right eye. Ten months after surgery, he presented with tube exposure due to dehiscence of the overlying conjunctiva and erosion of the scleral patch graft. Eleven days later, mild inflammation was found in the anterior chamber and anterior vitreous body, with the root of the tube surrounded by a plaque at the site of insertion in the anterior chamber. He was diagnosed with infectious endophthalmitis secondary to tube exposure. Two days later, since medical therapy was ineffective, the tube was withdrawn from the anterior chamber and irrigated with a polyvinyl alcohol-iodine solution, and the tube was tucked into the subconjunctival space. Complete resolution of the infection was achieved 1.5 months later. The tube was reinserted nasally into the anterior chamber and covered with a scleral patch graft and a free limbal conjunctival autograft. Thereafter, there has been no recurrence of infection or tube exposure. Twenty eight months after tube reinsertion, his right best-corrected visual acuity was 20/50 and intraocular pressure was 12 mmHg.ConclusionPrompt tube withdrawal and temporary subconjunctival tube placement followed by tube reinsertion may be effective for endophthalmitis associated with tube exposure after glaucoma drainage device surgery.

Thermochromic Polyvinyl Alcohol‐Iodine Hydrogels with Safe Threshold Temperature for Infectious Wound Healing (Adv. Healthcare Mater. 18/2021)

Antibacterial Hydrogels In article number 2100722 by Zhengbao Zha and co-workers, a blue polyvinyl alcohol-iodine hydrogel with thermochromic and laser-triggered liquefaction properties, originated from the dynamic interaction between iodine and polyvinyl alcohol, is explored as an effective alternative to conventional iodophor for safe and controllable management of multidrug-resistance bacterial-infected open wounds.

Thermochromic Polyvinyl Alcohol-Iodine Hydrogels with Safe Threshold Temperature for Infectious Wound Healing.

Iodophor (povidone-iodine) has been widely used for antibacterial applications in the clinic. Yet, limited progress in the field of iodine-based bactericides has been achieved since the invention of iodophor. Herein, a blue polyvinyl alcohol-iodine (PAI) complex-based antibacterial hydrogel is explored as a new generation of biocompatible iodine-based bactericides. The obtained PAI hydrogel maintains laser triggered liquefaction, thermochromic, and photothermal features for highly efficient elimination of bacteria. In vitro antibacterial test reveals that the relative bacteria viabilities of Escherichia coli (E.coli) and methicillin-resistant Staphylococcus aureus (MRSA) incubated with PAI hydrogel are only 8% and 3.8%, respectively. Upon single injection of the PAI hydrogel, MRSA-infected open wounds can be efficiently healed in only 5 days, and the healing speed is further accelerated by laser irradiation due to the dynamic interaction between iodine and polyvinyl alcohol, causing up to ∼29% of wound area being closed on day 1. In addition, a safe threshold temperature of skin scald (∼45°C) emerges for PAI hydrogels because of thermochromic properties, avoiding thermal injuries during irradiation. In addition, no observed toxicity or skin irritation is observed for the PAI hydrogel. This work expands the category of iodine-based bactericides for safe and controllable management of infected wounds.

Establishing Evidence for Use of Appropriate Medicines in the Operating Room

Various issues related to clinical use of medicines remain unclear, and pharmacists are expected to establish evidence for appropriate use of medicines. The present review summarizes our findings from three areas of research regarding the use of medicines in the operating room: 1) We evaluated the extent of extravasation injury due to thiopental (2.5 mg/100 μL) and propofol (1.0 mg/100 μL) at the macroscopic and histopathologic levels in a rat model. Thiopental, which causes tissue necrosis, can be classified as a "vesicant", and propofol can be classified as an "irritant". Moreover, warming strongly exacerbated the degeneration or necrosis induced by extravasation of thiopental. 2) The cytotoxicity of povidone-iodine solution (PVP-I) for ophthalmic use and that of polyvinyl alcohol-iodine solution (PAI) was compared using a human corneal epithelial cell line. Despite exhibiting equivalent antiseptic effects, the cytotoxicity of PVP-I diluted 16-fold was greater than that of PAI diluted 6-fold. After inactivation of iodine, the cytotoxicity of PVP-I persisted; therefore, to avoid corneal damage, antisepsis should be achieved with PAI. 3) The stability of 1 μg/mL adrenaline when used as an intraocular irrigating solution to maintain pupil dilation was evaluated. After mixing for 6 h, the adrenaline concentration was 65.2% (pH 8.0) of the initial concentration. Moreover, the low concentration of sodium bisulfite in the irrigating solution could have caused adrenaline reduction. Our results strongly suggest that intraocular irrigation solution containing adrenaline should be prepared just prior to use in surgery.

Comparative study of topical regimen for adenoviral kearoconjunctivitis by 0.1% fluorometholone with and without polyvinyl alcohol iodine.

The aim of this study was to compare the efficacy of the topical regimens of iodine/steroids vs. antibiotics/steroids in acute to subacute adenoviral keratoconjunctivitis. A prospective open-label study. Nineteen patients diagnosed with unilateral or bilateral adenoviral conjunctivitis at less than 1week from onset were enrolled in this study. Patients were divided randomly into two groups; group 1 was treated with 1.5% levofloxacin with 0.1% fluorometholone administered four times a day and group 2 was treated with a sixfold dilution of polyvinyl alcohol iodine (PAI) solution with 0.1% fluorometholone four times a day. Conjunctival samples from all affected eyes were obtained for real-time PCR. The total scores of acute signs (i.e., eyelid edema, conjunctival injecton, conjunctival discharge, follicules, pseudomembranes, subconjunctival hemorrhage) and symptoms, HAdV DNA copy number, and the presence of multiple subepithelial corneal infiltrates (MSI) were evaluated every 5 visits up to Day 30 after diagnosis. Comparing the total scores of acute signs and symptoms and viral load, we observed no significant differences between the two groups. At day 15 after diagnosis the proportion of patients with MSI in group 2 (35.7%) was significantly lower than in group 1 (0%). The impact of topical iodine/steroid therapy on acute signs and symptoms associated with adenoviral conjunctivitis is limited and not substantially different in the responses to antibiotics/steroids. However, this regimen results in a significant decrease in the incidence of MSI during the subacute phase of infection.

Evaluation of Retinal Function and Pathology After Intravitreal Injection of Povidone-Iodine and Polyvinyl Alcohol-Iodine in Rabbits.

PurposeThis study compared intraocular toxicity of intravitreally injected povidone-iodine (PI) and polyvinyl alcohol-iodine (PAI) in rabbits.MethodsIn each rabbit, 0.1 mL of PI or PAI solution was injected intravitreally into one eye and saline was injected into the other. PI was tested at available iodine concentrations of 0.05%, 0.1%, 0.2%, and 0.5%, and PAI at 0.05%, 0.1%, and 0.2% (n = 6 each). Electroretinograms were recorded before injection and 1, 7, and 14 days after injection. Pathological examinations of eyeballs were performed on day 15.ResultsMean b-/a-wave ratios of the electroretinograms did not change in eyes injected with 0.05%, 0.1%, or 0.2% PI (PI-0.05, PI-0.1, and PI-0.2, respectively) or in eyes injected with 0.05% or 0.1% PAI (PAI-0.05 and PAI-0.1, respectively) compared to saline-injected eyes, but was transiently impaired on day 1 in PAI-0.2 eyes. Histopathologically, no retinal abnormalities were observed in PI-0.05, PAI-0.05, or PAI-0.1 eyes. One PI-0.1 eye first showed localized inflammatory cell infiltration in the inferior retinal region. Two PI-0.2 eyes and one PAI-0.2 eye had retinal degeneration and inflammatory cell infiltration. In the PI-0.5 group, extensive inflammatory cell infiltration was observed in six eyes and inferior retinal detachment in five eyes.ConclusionsPI and PAI have equivalent retinal toxicity profiles, and retinal toxicity first affects the inner retinal layer in the inferior region. The highest non-retinotoxic vitreous concentration is 0.0033% available iodine from intravitreal injection of PI or PAI containing 0.05% available iodine.Translational RelevanceLow concentrations of PI or PAI can be used to wash the ocular surface during surgery or intravitreal injection to prevent endophthalmitis.

Polyvinyl alcohol-iodine induced corneal epithelial injury in vivo and its protection by topical rebamipide treatment.

Periocular povidone-iodine (PI) and polyvinyl alcohol-iodine (PAI) have had a major role in the prevention of endophthalmitis. The purpose of this study was to investigate the corneal epithelial toxicity of PAI in a rabbit eye model using corneal resistance (CR) measurement, which is a good indicator of cell barrier function. Rabbit eyes were administered PAI solution at 4-, 6-, 8-, or 16-fold dilution with physiological saline solution (saline) or saline alone (control), to the conjunctival sac with/without wash-out with saline. Corneal epithelial injury assessed by fluorescein staining and the CR ratio was measured at 10 minutes (min) to 96 hours (h) after the initial administration. Histological observation was performed in the eyes following the PAI or control administrations. At 120 min after administration of PAI solution, the CR ratio was decreased and superficial punctate keratopathy (SPK) was significantly increased in each of the PAI-administered groups compared to the control. Recovery of CR and SPK after administration of 6- or 8-fold dilution of PAI was significantly delayed in eyes that were not subsequently washed with saline compared with eyes that were. Pre- or post-instillation of 2% rebamipide ophthalmic suspension significantly reduced PAI induced-SPK and -decrease of CR ratio. The CR method was able to accurately and quantitatively evaluate fine corneal epithelial injury. It is suggested that eyes should be washed with saline solution after administration of PAI solution or the instillation of rebamipide to prevent or reduce corneal epithelial injury.

This issue of ACTA

The cover illustration shows a prolene thread inserted into Schlemm′s canal as reported by Grieshaber et al. in this issue of Acta. Klemp et al. in Copenhagen describe exudative retinal detachment, cataract formation and melanocytic tumours as the characteristic ocular findings in uveal melanocytic proliferation. Campos et al. in Portugal consider the role of the choroid in diabetic macular oedema and how OCT studies of the choroid advance this field of research. Jørstad et al. in Oslo found positive results with aflibercept in AMD eyes which were resistant to ranibizumab and bevacizumab injections. Many eyes required more than bimonthly aflibercept injections. Vujosevic et al. in Italy emphasize inflammatory biomarkers in diabetic macular oedema such as hyperreflective retinal spots, subfoveal neuroretinal detachment and increased foveal autofluorescence. These biomarkers improved with dexamethasone treatment. Subhi and Lykke Sørensen in Denmark correlated systemic leucocyte activity with onset and size of neovascular lesions in AMD. They suggest that inflammation plays a role in the pathophysiology. Sauer et al. in Germany used fluorescence lifetime imaging to map pigment distribution and evaluate its role in macular hole formation. Hamoudi et al. in Denmark found no difference in corneal endothelial density between combined and separated phacoemulsification and vitrectomy for epiretinal membrane. Makdoumi et al. in Sweden and the USA used blue light and riboflavin to kill resistant staphylococci and suggest this approach may work in corneal infections. Margulis et al. in the Netherlands, Spain and Denmark examined use of nonsteroidal anti-inflammatory eye drops. These were used with cataract surgery and for allergic conjunctivitis. Pärssinen and Kauppinen in Finland found astigmatism to increase with myopia. Corneal astigmatism predominates. Grieshaber et al. in South Africa and Switzerland recommend the Stegmann Schlemm′s canal expander to lower intraocular pressure in patients with moderate to advanced open angle glaucoma. Quérat and Chen in Sweden recommend ICARE® self-tonometry. Day-to-day variations are seen in most patients. Mrowicka et al. in Poland propose that insufficient antioxidant capacity may play a role in age related macular degeneration. This hypothesis is based on study of enzymes and genes related to antioxidant activity. Pilat et al. in UK used hand-held OCT to image anterior segment dysgenesis in children. The following articles are published electronically only and are accessible on www.actaophtalmologica.com, where you can also access the printed articles. Nitta et al. in Japan report an increase in retinal oximetry readings in retinal venules following glaucoma surgery and lowering of intraocular pressure. Tanito et al. in Japan recommend microhook trabeculotomy in glaucoma patients. It lowers IOP and reduces need for glaucoma medications. Mansouri and Shaarawy in the USA and Switzerland fond similar outcomes with scanning laser trabeculoplasty and selective laser trabeculoplasty. Lanza et al. in Italy used light backscattering with in vivo corneal confocal microscopy to evaluate changes in corneal layers in patients with Sjögren syndrome and dry eyes. Shimada et al. in Japan found reduced anterior chamber bacterial contamination with either 0.025% povidone-iodine or 0.0025% polyvinyl alcohol iodine irrigation of ocular surface. Peiretti et al. in Italy, the Netherlands, Saudi Arabia and the USA examined retinal folds following retinal detachment repair. This was not influenced by use of heavy liquids in surgery or postoperative positioning. Chan et al. in Hong Kong, Singapore and UK seek ways to measure and control emulsification of intraocular silicone oil. Kang et al. in Korea measured greater choroidal thickness in eyes with vitreoretinal traction. This was reversed following epiretinal membrane surgery and release of the traction. Jonas et al. in India and Germany found myopic retinopathy to be rare in rural India. It was associated with open angle glaucoma. Carreño et al. in Spain, USA and UK measured several inflammatory cytokines in tear fluid in uveitis patients. Bray et al. in UK suggest that portable electronic vision enhancement systems are cost-effective to improve near vision. However, it may not provide cost-effective improvement in quality of life. Babeau et al. in France comment on an article on using adaptive optics for screening chloroquine retinopathy. Parrovano et al. in Italy used OCT angiography to monitor reduction in neovascular lesions. Van Asten et al. in the Netherlands found positive outcomes with aflibercept in AMD patients unresponsive to bevacizumab. Lytvynchuk in Ukraine surgically removed a retinal branch artery embolus. Dimopoulos et al. in Germany used autologous thrombocyte serum for macular hole surgery. Grewal et al. in USA used intraoperative OCT to guide placement of Argus II retinal prosthesis. Huynh et al. in the USA found no benefit from dilated fundus examination in patients with spontaneous subconjunctival haemorrhage. Qu-Knafo et al. in France suggest that eyes with DME and serous retinal detachment may show greater improvement with ranibizumab than eyes without serous detachment. I hope you are enjoying a pleasant summer and Acta fits into your summer reading schedule.

Reduced anterior chamber contamination by frequent surface irrigation with diluted iodine solutions during cataract surgery.

To verify that ocular surface irrigation with 0.025% povidone-iodine (PI) or 0.0025% polyvinyl alcohol-iodine (PAI) during cataract surgery minimizes bacterial contamination of the anterior chamber. The study was a prospective, interventional case series. First, the bactericidal effect of PI or PAI against Staphylococcus aureus was evaluated invitro. Next, in 400 eyes undergoing cataract surgery, the ocular surface was irrigated every 20seconds during surgery with balanced salt solution (BSS; 200 eyes) or BSS containing 0.025% PI (100 eyes) or 0.0025% PAI (100 eyes). At the completion of surgery, anterior chamber fluid was cultured bacteriologically. Visual acuity (VA) and corneal endothelial cell density were measured before and 7days after surgery. A marked bactericidal effect was observed when S.aureus was directly exposed for 15seconds to 0.01% PI or 0.001% PAI diluted in BSS. When the two solutions were stored at room temperature, bactericidal effect did not attenuate after 60min. The bacterial detection rate at the completion of surgery was significantly reduced in 0.025% PI (0%, 0/100 eyes) or 0.0025% PAI group (0%, 0/100 eyes) compared to BSS group (5%, 10/200 eyes) (p=0.0340). No differences in postoperative visual acuity and postoperative corneal endothelial cell density were observed between three groups. In cataract surgery, irrigation every 20seconds of the operative field with 0.025% PI or 0.0025% PAI, both of which contain 0.0025% available iodine concentration, achieved a very low bacterial contamination rate in the anterior chamber.

Survey of Japanese ophthalmic surgeons regarding perioperative disinfection and antibiotic prophylaxis in cataract surgery.

PurposeTo elucidate Japanese trends for perioperative disinfection and antibiotic selection during cataract surgeries.MethodsPerioperative iodine use and antibiotic prophylaxis for cataract surgery were surveyed in eight regions in Japan by mail or through interviews from February 1 to March 1, 2014.ResultsWe surveyed 572 surgeons, of whom 386 (67%) responded. Most of the surgeons (94%) used iodine compounds before surgery for periocular skin disinfection (povidone–iodine [PI]: 79%; polyvinyl alcohol-iodine [PAI]: 15%) or conjunctival disinfection (85%; PI: 36%; PAI: 49%). Preoperative conjunctival iodine was primarily used as an eye wash (irrigation: 95%) and less often as an eye drop (5%). It was determined that 31% of surgeons waited 30 seconds or more between periocular disinfection and conjunctival disinfection. During surgery, 14% of surgeons used iodine several times, including immediately before intraocular lens insertion, and 7% used the Shimada technique (repeated iodine irrigation). Preoperative antibiotic eye drops were used by 99% of surgeons, and antibiotics were added to the irrigation bottle by 22%. The surgeons reported use of subconjunctival antibiotic injections (23%), antibiotic ointments (79%), and intracameral antibiotics (7%: 22 moxifloxacin; 6 levofloxacin). All surgeons prescribed postoperative eye drops, with 10% initiating the drops on the day of surgery.ConclusionIodine compounds are commonly used preoperatively, but few institutions use iodine compounds intraoperatively, particularly with repeated application. The selection of antibiotic administration and disinfection technique has to be at the surgeon’s discretion. However, intracameral antibiotic and intraoperative iodine compound use are techniques that should be widely recognized.

Necrotizing Nocardial Scleritis Successfully Treated with Surgical Debridement and Topical Polyvinyl Alcohol Iodine and Antibiotics

To report a case of necrotizing nocardial scleritis treated with surgical debridement and topical polyvinyl alcohol iodine (PAI) and antibiotics. A 78-year-old man underwent phacoemulsification with intraocular lens implantation in the left eye. He had an uncomplicated postoperative course for 2 months but then developed infectious scleritis. The patient received intensive antibiotics treatments; however, the lesion did not respond. Because of the poor response, Nocardia infection was suspected, and the lesion was repeatedly scraped and the patient was treated with systemic trimethoprim/sulfamethoxazole (TMP-SMX, 800 mg/day) and topical PAI (0.033%, 4 times/day). Cultures of the scrapings grew Nocardia. The treatment led to a complete resolution of the infection. Necrotizing nocardial scleritis can be treated by surgical debridement and systemic TMP-SMX and topical PAI.

Expanding the potential for waste polyvinyl-alcohol

Expanded polyvinyl-alcohol (PVA) was successfully prepared using a similar process to that of starch expansion. The addition of an iodine solution was necessary to facilitate expansion and led to surface areas of up to 143.1 m2 g−1. The use of recycled material from LCD screens required no additional iodine and produced an expanded material with high surface areas (95.0 m2 g−1) and total pore volumes (0.56 cm3 g−1). The PVA–iodine complexes were found to better mimic the interactions between amylose and amylopectin in starch expansion.

Preoperative disinfection of the conjunctival sac with antibiotics and iodine compounds: A prospective randomized multicenter study

To compare disinfection by povidone-iodine (PI) solution with that by polyvinyl alcohol-iodine (PAI) solution in preoperative eyewash and to assess the optimal duration of the preoperative application of 0.5% levofloxacin (LVFX) ophthalmic solution. Two-hundred-seventy-two elderly cataract patients who had undergone phacoemulsification aspiration with intraocular lens insertion at 12 clinical facilities in Japan were randomized into three groups: 3-day, 1-day, and 1-h preoperative application of 0.5% LVFX ophthalmic solution. Each LVFX group was further divided into two subgroups; the patients in one subgroup were treated with diluted PI eyewash, and those in the second subgroup with diluted PAI eyewash, immediately before the surgery. Thus, a total of six groups were studied. Conjunctival scrapings were collected four times: before LVFX application, after LVFX application, after the eyewash with iodine compounds, and after the surgery. Samples of the aqueous humor were collected immediately after the surgery. All samples were cultured aerobically and anaerobically. The 3-day application of LVFX had a significantly higher disinfection rate than the 1-day or 1-h applications (P<0.05). The disinfection rate of PI was 78.0%, and that of PAI was 79.4%; PAI was not inferior to PI as a preoperative disinfectant. However, new isolates, mainly Propionibacterium acnes and Staphylococcus epidermidis, were detected after LVFX application and even after use of the eyewash with iodine compounds. Three-day administration of LVFX ophthalmic solution and use of an eyewash with diluted iodine compounds is effective for preoperative disinfection. However, complete elimination of bacteria from the conjunctival sac is difficult.

Effect of addition of inorganic acids or alkalis on gelation of polyvinyl alcohol aqueous solution by gamma-ray irradiation.--Color development with iodine--.

Below the critical concentration of polyvinyl alcohol, the effect of inorganic acids or alkalis on gelation of polyvinyl alcohol aqueous solution was investigated by color development with iodine after gamma-ray irradiation. The absorbances of the polyvinyl alcohol-iodine complex decreased remarkably in the presence of nitric or perchloric acid. These acids decompose and form oxygen or hydrogen peroxide which oxidize the polymer and leads to a fading of the color. On addition of sulfuric, phosphoric and hydrochloric acids, the absorbances decrease in the order that agrees with that of the acidity of these acids at the same molarity. In the alkaline solution the absorbances decrease by the addition of sodium hydroxide and aqueous ammonia in the order that agrees with that of the basicity of these alkalis. These results indicate that the gel formation is caused by the radiolysis of water. As a result of chemical analysis, these additives are considered not to be attached to the polymer.

Study of the Polyvinyl Alcohol-Borate-Iodine Complex III. Detection of Borates in Urine

A survey of the prevalence of boric acid toxicity indicates the difficulty encountered in detecting cases of poisoning by this commonly used substance. Because of this situation, an investigation was carried out utilizing a previously reported method for the detection of borates by the polyvinyl alcohol-borate-iodine reaction. The test was extended in this study to permit the detection of boric acid in the urine of poisoned animals. Rabbits were fed varying quantities of boric acid, and urine samples were collected. After concentration of the urine sample, the polyvinyl alcohol-iodine reagent was applied to the residue. Results of both in vitro and in vivo studies indicate that this method is capable of detecting as little as 0.3 mg. of boric acid (0.05 mg. B). A survey of the prevalence of boric acid toxicity indicates the difficulty encountered in detecting cases of poisoning by this commonly used substance. Because of this situation, an investigation was carried out utilizing a previously reported method for the detection of borates by the polyvinyl alcohol-borate-iodine reaction. The test was extended in this study to permit the detection of boric acid in the urine of poisoned animals. Rabbits were fed varying quantities of boric acid, and urine samples were collected. After concentration of the urine sample, the polyvinyl alcohol-iodine reagent was applied to the residue. Results of both in vitro and in vivo studies indicate that this method is capable of detecting as little as 0.3 mg. of boric acid (0.05 mg. B).