Chemical shift changes and line narrowing in 13C NMR spectra of hydrocarbon clathrate hydrates.

The solid-state (13)C NMR spectra of various guest hydrocarbons (methane, ethane, propane, adamantane) in clathrate hydrates were measured to elucidate the local structural environments around hydrocarbon molecules isolated in guest-host frameworks of clathrate hydrates. The results show that, depending on the cage environment, the trends in the (13)C chemical shift and line width change as a function of temperature. Shielding around the carbons of the guest normal alkanes in looser cage environments tends to decrease with increasing temperature, whereas shielding in tighter cage environments tends to increase continuously with increasing temperature. Furthermore, the (13)C NMR line widths suggest, because of the reorientation of the guest alkanes, that the local structures in structure II are more averaged than those in structure I. The differences between structures I and II tend to be very large in the lower temperature range examined in this study. The (13)C NMR spectra of adamantane guest molecules in structure H hydrate show that the local structures around adamantane guests trapped in structure H hydrate cages are averaged at the same level as in the α phase of solid adamantane.

Elucidation of the relationship between masticatory muscle activity and masticatory movement. Report 1. Mechanism of occlusal force generation.

OBJECTIVES: The purpose of this study was to elucidate how masticatory muscles are involved in the generation of occlusal force. MATERIALS AND METHODS: The experiment was conducted by fabricating an experimental apparatus for a unilateral occlusion model with the masticatory muscles imparted. The experimental apparatus was fabricated by enlarging the lateral photograph of a dried adult skull specimen 3.5 times larger than that of a standard adult and drawing the outlines of the maxilla and mandible, canines and molars of the upper and lower jaws, and temporomandibular joint on a wooden board. The masticatory muscles used in the experiment were the masseter muscle, the temporalis muscle (anterior and posterior muscle bundles), and the lateral pterygoid muscle. For the measurement of the contractile force of the masticatory muscle, we used the spring scale. For the food, we used cut plastic cylinders. RESULTS: The results of the experiment revealed the following: First, the occlusal force was generated under the condition that the contraction forces of all the masticatory muscles were balanced. Second, when the occlusal force was applied to food, the occlusal planes of the upper and lower jaws were parallel. Third, the occlusal force occurred perpendicular to the occlusal plane. Fourth, the occlusal force was generated with a force greater than the contraction force of the individual masticatory muscles. And finally, even if occlusal force was applied to the food, the occlusal force did not load the temporomandibular joint. CONCLUSION: Occlusal force is not generated by the action of a single masticatory muscle but under the balanced contractile force of all masticatory muscles. The occlusal force then emerges with a force greater than the contraction force of all the masticatory muscles, and its direction occurs perpendicular to the occlusal plane.

Nighttime home blood pressure lowering effect of esaxerenone in patients with uncontrolled nocturnal hypertension: the EARLY-NH study.

There is limited evidence on the blood pressure (BP)-lowering effect of esaxerenone on home BP, including nighttime BP. Using two newly developed nocturnal home BP monitoring devices (brachial and wrist), this multicenter, open-label, prospective study investigated the nighttime home BP-lowering effect of esaxerenone in patients with uncontrolled nocturnal hypertension being treated with an angiotensin receptor blocker (ARB) or calcium-channel blocker (CCB). In total, 101 patients were enrolled. During the 12-week study period, change in nighttime home systolic/diastolic BP from baseline to end of treatment measured by the brachial device was -12.9/-5.4 mmHg in the total population and -16.2/-6.6 and -10.0/-4.4 mmHg in the ARB and CCB subcohorts, respectively (all p < 0.001). For the wrist device, the change was -11.7/-5.4 mmHg in the total population and -14.6/-6.2 and -8.3/-4.5 mmHg in each subcohort, respectively (all p < 0.001). Similar significant reductions were shown for morning and bedtime home BP and office BP. Urinary albumin-to-creatinine ratio, N-terminal pro-brain natriuretic peptide, and cardio-ankle vascular index improved in the total population and each subcohort. Incidences of treatment-emergent adverse events (TEAEs) and drug-related TEAEs were 38.6% and 16.8%, respectively; most were mild or moderate. The most frequent drug-related TEAEs were associated with serum potassium elevation (hyperkalemia, 9.9%; blood potassium increased, 3.0%); however, no new safety concerns were raised. Esaxerenone was effective in lowering nighttime home BP as well as morning and bedtime home BP and office BP, safe, and showed organ-protective effects in patients with uncontrolled nocturnal hypertension. Caution is warranted regarding elevated serum potassium levels. This study investigated the effect of esaxerenone on nighttime home BP and organ damage (UACR and NT-proBNP) in patients with uncontrolled nocturnal hypertension despite treatment with an ARB or CCB. Our results show that safe 24-h BP control and organ protection are possible with esaxerenone.

Benzalkonium Chloride-Induced Corneal Epithelial Injury in Rabbit Reduced by Rebamipide.

Purpose: We assessed the effect of rebamipide ophthalmic solution on corneal epithelial injury due to benzalkonium chloride (BAK) by fluorescein (FL) staining and corneal resistance (CR). Methods: After determining the absence of corneal epithelial damage by FL and CR, rebamipide ophthalmic solution (50 µL) was instilled five times, each interspaced by 5 min, into one eye of mature New Zealand white rabbits, and likewise physiological saline was instilled into the contralateral eye as the control. After 30 min, eyes were similarly treated with one of the following solutions: BAK solution 0.02%, latanoprost ophthalmic solution (0.02% BAK), or latanoprost ophthalmic solution without BAK. The presence of corneal epithelial damage was quantitated at 10, 30, and 60 min by CR after the last instillation. FL staining was also performed at 60 min after the last instillation. Results: CR ratios (%) at 60 min after the last instillation in rebamipide/BAK and rebamipide/latanoprost (0.02% BAK) groups were significantly increased by 18.3% and 25.6% compared with saline/BAK and saline/latanoprost (0.02% BAK) groups, respectively (P < 0.05). Findings by FL staining were consistent with those by CR; BAK and latanoprost with BAK groups were positive, and eyes with the most severe area and density of corneal epithelial damage (A2D2) were in the saline/BAK group. Conclusion: The rebamipide ophthalmic solution reduces the severity of corneal epithelial injury caused by BAK, an ophthalmic solution preservative.

13C chemical shifts of propane molecules encaged in structure II clathrate hydrate.

Experimental NMR measurements for (13)C chemical shifts of propane molecules encaged in 16-hedral cages of structure II clathrate hydrate were conducted to investigate the effects of guest-host interaction of pure propane clathrate on the (13)C chemical shifts of propane guests. Experimental (13)C NMR measurements revealed that the clathrate hydration of propane reverses the (13)C chemical shifts of methyl and methylene carbons in propane guests to gaseous propane at room temperature and atmospheric pressure or isolated propane, suggesting a change in magnetic environment around the propane guest by the clathrate hydration. Inversion of the (13)C chemical shifts of propane clathrate suggests that the deshielding effect of the water cage on the methyl carbons of the propane molecule encaged in the 16-hedral cage is greater than that on its methylene carbon.

Comparative study of the usefulness of a novel insulin therapy in Japanese patients with Type 2 diabetes for concomitant use of an oral antidiabetic agent with twice-daily dosing either of insulin aspart, biphasic insulin aspart-30, or insulin detemir: Two times Insulin injection Combined with oral therapy Efficacy Study (TWICE study).

OBJECTIVES: It is common to treat type 2 diabetes by regular injections of insulin. We compared the efficacy and safety of twice-daily administration of short-acting, premixed, and long-acting insulins. METHODS: This was a multi-center, randomized, open-label, 52-week study. Patients were randomized to administer twice daily short-acting analog insulin (Aspart) plus a sulfonylurea (SU), premixed 70/30 analog insulin (Mix), or long-acting insulin (Detemir) plus a glinide derivative. RESULTS: Twelve (mean baseline HbA1c 9.86±1.71%), eight (9.24±1.14%), and eight (11.26±1.81%) patients were treated with Aspart, Mix, or Detemir, respectively, for 52 weeks. After 12 weeks, the reductions in HbA1c were similar in the groups. A further significant reduction in HbA1c occurred between weeks 12 and 52 in the Detemir, but not the Aspart or Mix groups. After 52 weeks, the target of an HbA1c <7.4% was achieved in 16.7% of the Aspart group, 37.5% of the Mix group, and 12.5% of the Detemir group (no significant differences among the three groups by χ2 analysis). The mean changes from baseline in blood glucose concentration measured after breakfast, and before and after dinner, were also similar in each group. CONCLUSIONS: Early and meaningful reductions in HbA1c were achieved by twice-daily administration of a premix, aspart plus an SU, and detemir plus a glinide, without severe hypoglycemia or an increase in body mass. However, the target HbA1c was achieved in relatively few participants, perhaps due to an insufficient dose of insulin or the small study size.

Dissociation behavior of methane--ethane mixed gas hydrate coexisting structures I and II.

Dissociation behavior of methane-ethane mixed gas hydrate coexisting structures I and II at constant temperatures less than 223 K was studied with use of powder X-ray diffraction and solid-state (13)C NMR techniques. The diffraction patterns at temperatures less than 203 K showed both structures I and II simultaneously convert to Ih during the dissociation, but the diffraction pattern at temperatures greater than 208 K showed different dissociation behavior between structures I and II. Although the diffraction peaks from structure II decreased during measurement at constant temperatures greater than 208 K, those from structure I increased at the initial step of dissociation and then disappeared. This anomalous behavior of the methane-ethane mixed gas hydrate coexisting structures I and II was examined by using the (13)C NMR technique. The (13)C NMR spectra revealed that the anomalous behavior results from the formation of ethane-rich structure I. The structure I hydrate formation was associated with the dissociation rate of the initial methane-ethane mixed gas hydrate.

Mental distress and health-related quality of life among type 1 and type 2 diabetes patients using self-monitoring of blood glucose: A cross-sectional questionnaire study in Japan.

AIMS/INTRODUCTION: The present multicenter, cross-sectional survey was initiated to evaluate self-monitoring of blood glucose (SMBG)-associated mental distress among patients with diabetes. MATERIALS AND METHODS: The survey was carried out in patients with type 1 diabetes and type 2 diabetes using SMBG recruited from 42 medical institutions. Profiles of Mood States 2 and diabetes therapy-related quality of life questionnaires were used to evaluate mood status and health-related quality of life. Two original questionnaires were also developed to evaluate SMBG 'importance,' 'painfulness' and 'confidence' among patients, and to evaluate physician attitudes to SMBG use. RESULTS: Questionnaires from 517 type 1 diabetes and 1,648 type 2 diabetes patients showed that 46.0% of type 1 diabetes and 37.5% of type 2 diabetes patients reported 'painfulness,' and that these patients reporting 'painfulness' showed significantly higher Profiles of Mood States 2 scores, lower diabetes therapy-related quality of life scores and higher glycated hemoglobin compared with those not reporting 'painfulness,' whereas the number of their daily SMBG tests were comparable. Patients reporting 'painfulness' also reported that SMBG use was significantly less important. Whether or not patients recognized the importance of SMBG use was well correlated with the frequency of physicians checking patient diaries. CONCLUSIONS: Type 1 diabetes and type 2 diabetes patients reporting 'painfulness' in SMBG use had more mental distress, lower health-related quality of life and higher glycated hemoglobin regardless of their number of daily SMBG tests. The importance of SMBG use was recognized less by patients experiencing pain, and the importance of SMBG use was recognized more in medical institutions in which physicians regularly checked SMBG diaries to provide meaningful feedback to patients in clinical settings.

Expression of matrix metalloproteinases in wound healing after glaucoma filtration surgery in rabbits.

PURPOSE: To investigate the protein and mRNA expressions of matrix metalloproteinases (MMPs), gelatinolytic activity and localization of MMP activity in wounds after glaucoma filtration surgery in rabbits. METHODS: Sixty eyes of 30 rabbits were removed 1, 3, 7, 14 and 120 days after the surgery and used for this experiment. Protein and mRNA expressions were analyzed by immunohistochemistry and laser capture microdissection/real-time RT-PCR, respectively. The gelatinolytic activity was analyzed by gelatin zymography and the localization was studied using in situ zymography. RESULTS: By immunohistochemistry, expression of MMP-1, MMP-2, MMP-3, MMP-9 and MT1-MMP was detected in the wounds, most markedly 3 days after the surgery. MMP-positive cells were predominantly macrophages. Expression of MMP-9 and MT1-MMP mRNAs was verified by RT-PCR. Gelatinolytic activities corresponding to proMMP-2 and the active form of MMP-2 were detected in the wounds 3 and 7 days after surgery. In situ zymography localized gelatinolytic activities at the wound site. These activities were almost completely abolished by an MMP inhibitor, indicating that the gelatinolytic activity belongs to metalloproteinases. CONCLUSIONS: MMPs, particularly MMP-2/MT1-MMP, play important roles in the degradation of the extracellular matrix in the wound healing process after glaucoma filtration surgery and may represent an important target for therapeutic intervention after glaucoma filtration surgery.

[Intraocular penetration of cefotiam hydrochloride, a kind of cephalosporin after filtration surgery in rabbit eyes].

PURPOSE: In this study, we measured the cefotiam dihydrochloride (CTM) concentration in ocular tissue after filtration surgery in rabbit eyes. METHODS: CTM (20 mg/kg body weight) was administered intravenously 30 min before filtration surgery which was performed by double flap procedure on the right eyes of white rabbits. The aqueous humor and serum were extracted at 10 min after surgery and at 30 min, 60 min, and 120 min. Drug concentration in all of the specimens was measured by high performance liquid chromatography (HP-LC). RESULT: The CTM concentrations of aqueous humor in the nonoperated eyes were 0.44 +/- 0.16(mean +/- standard deviation) microg/ml (n = 4) (40 min after intravenous dosage), 0.36 +/- 0.17microg/ml (n = 4) (60 min after intravenous dosage), 0.38 +/- 0.34, microg/ml(n = 3) (90min after intravenous dosage) and 0.27 +/- 0.10 microg/ml (n = 5) (150 min after intravenous dosage). In contrast, CTM concentration in the aqueous humor of the operated eyes was 2.4 +/- 0.95 microg/ml (n = 4) at 10 min after surgery (40 min after intravenous dosage), 2.11 +/- 1.10 microg/ml (n = 4) at 30 min after surgery (60 min after intravenous dosage), 1.18 +/- 0.78 microg/ml (n = 4) at 60 min after surgery (90 min after intravenous dosage) and 0.47 +/- 0.1 microg/ml (n = 5) at 120 min after surgery (150 min after intravenous dosage). The intraocular penetration of CTM at 10 min and at 120 min after filtration surgery was significantly higher in comparison with the drug concentration in the nonoperated eyes (p < 0.05). CONCLUSION: The intraocular penetration of CTM after filtration surgery was much higher in comparison with the drug concentration in the nonoperated eyes. These results may be useful to predict the intraocular penetration of CTM in human eyes after filtration surgery.

Low vitamin E level as a subliminal risk factor in a rat model of prednisolone-induced cataract.

PURPOSE: To investigate the relationship between vitamin E deficiency and prednisolone-induced cataract formation, long-term examination of lens changes was performed in rats under the condition of vitamin E deficiency or supplementation and administration of prednisolone. METHODS: Rats were divided into six groups: normal chow (N), vitamin E-deficient chow (ED), normal chow with prednisolone instillation (NP), vitamin E-deficient chow with prednisolone instillation (EDP), NP treatment with vitamin E supplementation (NP+VE), and EDP treatment with vitamin E supplementation (EDP+VE). Prednisolone (1 mg/kg small middle dot d) and vitamin E (5%; 10 microL per administration per eye, 1 mg/kg small middle dot d) were applied in the cul-de-sac. Lens changes were documented and analyzed. Vitamin E status was confirmed by measuring peroxide-induced hemolysis. RESULTS: After 15 months, 91.7% of the eyes in the EDP group showed development of anterior and posterior cortical cataracts. Supplementation with vitamin E significantly reduced cataract formation (to 38.9% of eyes). Neither a vitamin E-deficient diet nor prednisolone treatment alone significantly increased cataract formation. Hemolysis-susceptibility tests confirmed the expected vitamin E status of rats fed vitamin E-deficient chow and rats supplemented with eye drops containing vitamin E. CONCLUSIONS: Vitamin E deficiency and long-term prednisolone treatment together cause cataracts. Singly, however, both conditions are subliminal cataractogenic risk factors.

Dihydrofolate Reductase in Starfish Oocytes and Embryos: Developmental Consequences of Its Inhibition by Methotrexate1 : (starfish/dihydrofolate reductase/methotrexate/DNA synthesis/early development).

Dihydrofolate reductase in immature oocytes of the starfish, Asterina pectinifera, is estimated to be 12 pg per oocyte. After completion of meiosis, the quantity of the enzyme is approximately 20 pg per egg. The content of the enzyme in the egg is kept nearly constant at this value from fertilization to the beginning of blastulation. Methotrexate, an analogue of dihydrofolate, at 20 µM did not affect meiotic maturational process and fertilization, but inhibited embryonic development at the 512-cell stage which corresponds to the beginning of blastulation. Incorporation of externally supplied deoxy[3 H]uridine into DNA of the embryos cultured in the continuous presence of 20 µM of methotrexate stopped at the 256-cell stage, suggesting that the cessassion of development of the embryo at the 512-cell stage was caused by inhibition of DNA synthesis at the preceding stage. Uptake of [3 H]methotrexate was low at early cleavage stages but increased just before blastulation. Externally supplied 1 mM of thymidine counteracted the inhibitory effect of methotrexate at 20 µM, suggesting that the starvation of the methotrexate-treated embryo for thymidine nucleotides halted DNA synthesis at the beginning of blastulation.

Biliary cystadenocarcinoma followed up as benign cystadenoma for 10 years.

We describe a case of biliary cystadenocarcinoma that showed a longterm clinical course. A 69-year-old Japanese man was admitted to our hospital because of abdominal discomfort. The patient had been diagnosed with benign cystadenoma of the liver at another hospital in 1987 and had been followed up for 10 years. Abdominal ultrasonography (US) and computed tomography (CT) scan demonstrated a unilocular cystic lesion, which included multiple conspicuous papillary protrusions in the left hepatic lobe. Left lateral segmentectomy was performed, and intraoperative cholangiography revealed a communication between the cystic tumor and intrahepatic bile duct. The tumor contained clear mucinous fluid and enfolded multiple yellowish papillary projections on the cystic wall. Histological examination showed the tumor to be biliary cystadenocarcinoma. The patient is doing well 4 years after the operation.

Environmental temperature and cataract progression in experimental rat cataract models.

PURPOSE: To clarify whether or not ambient temperature relates to cataract development or the progression of cataract formation. MATERIALS AND METHODS: 36 Brown Norway rats were divided into two groups, a high-temperature (35 +/- 2 degrees C, H = high) breeding group and a regular-temperature (24 +/- 2 degrees C, L = low) group. Each group was further divided into an experimentally induced diabetic cataract subgroup (50 mg/kg streptozotocin, DM), an ultraviolet B exposure-induced cataract subgroup (200 mJ/cm2, UV), and a normal control subgroup (C = control). Slit-lamp microscopy and an anterior image analysis system (EAS-1000) were used to evaluate lens changes. RESULTS: Both the HC and HUV groups in the 35 degrees C conditions showed higher light scattering than that of the 24 degrees C conditions (LC and LUV) 3 weeks after the start of the experiment. Nine weeks after the start of the experiment, all the rats of the UV subgroups (HUV and LUV) developed anterior subcapsular cataract. The temperature did not have much influence on the progression of the UV-B-induced cataract. From 18 days after the start of the experiment, the HC subgroup showed a wider light scattering area than the LC. An increase in abnormal nuclear scattering light in the crystalline lens of group HC was found in 9 weeks after the start of the experiment, and at the end of the experiment (78 weeks later), dense abnormal nuclear light scattering was found including the prenuclear area. In contrast, the HDM group in the 35 degrees C conditions showed slower cataract progression than that of the LDM group at 24 degrees C room temperature. CONCLUSIONS: Although further experiments are necessary before we can draw any conclusions about temperature and nuclear changes, paying attention to the effects of temperature on the lens is worthwhile.

High prevalence of nuclear cataract in the population of tropical and subtropical areas.

The authors have conducted cataract epidemiological studies in four climatically and racially different places and compared the data. The survey places were Noto and Amami in Japan, Reykjavik in Iceland, and Singapore. The evaluation and grading of lens opacities were done using graphic analysis of Scheimpflug and retro-illumination images. The prevalence of nuclear opacity was extremely high in the Singapore group, followed by Amami. The main type of lens opacity was nuclear in the Singapore group and cortical in the Noto and Icelandic groups. The characteristic lens opacity in Amami was in between the above two groups. No significant difference was seen in the prevalence of nuclear opacity between males and females in any of the groups. Although the common factors of the living conditions in the subjects with a high prevalence of nuclear opacity appear to be high UV exposure and high ambient temperature, future investigations should be made to disclose the possible cause.

The effect of the corneal epithelium on the intraocular penetration of fluoroquinolone ophthalmic solution.

PURPOSE: Pharmacokinetic studies of antibacterial agents for infectious eye diseases have usually been performed on normal rabbit eyes. In this study, the intraocular penetration of fluoroquinolone ophthalmic solutions was determined in normal rabbit eyes and in rabbit eyes that had the corneal epithelium intentionally removed. METHODS: We determined the intraocular penetration of ofloxacin (OFLX), levofloxacin (LVFX), and norfloxacin (NFLX), fluoroquinolone ophthalmic solutions that are already on the market and undergoing clinical studies, by injecting 50 microl of each solution into the cul-de-sacs of rabbit eyes three times at 15-min intervals. The drug concentration at 10, 30, 60, 120, and 240 min after final instillation was determined by high-performance liquid chromatography. RESULTS: The maximum concentration in the aqueous humor of normal rabbit eyes was 2.09 +/- 1.56 microg/ml (60 min, OFLX), 2.57 +/- 1.00 microg/ml (30 min, LVFX), and 0.42 +/- 0.12 microg/ml (120 min, NFLX). The drug concentration in the aqueous humor of eyes with intentionally removed corneal epithelium was 12.50 +/- 5.62 microg/ml (30 min, OFLX), 9.02 +/- 2.45 microg/ml (60 min, LVFX), and 8.54 +/- 5.17 microg/ml (30 min, NFLX). The drug penetration of the eye drops into eyes with removed corneal epithelium was around 6 times (OFLX), 3.5 times (LVFX), and 20 times (NFLX) higher than the penetration into the eye with normal cornea. CONCLUSION: Among the pharmacokinetic parameters of the three ophthalmic solutions according to the one-compartment model, the maximum concentration in the aqueous and the area under the concentration-time curve in the aqueous tended to be higher in the eyes with intentionally removed corneal epithelia than in those with normal corneas.

Early manifestation of vogt-koyanagi-harada disease as unilateral posterior scleritis.

PURPOSE: To describe a patient with an initial diagnosis of unilateral posterior scleritis who developed bilateral Vogt-Koyanagi-Harada (VKH) disease 12 months later. CASE: A 38-year-old woman was diagnosed with posterior scleritis in her right eye at successive examinations. The left eye showed no signs of ocular inflammation. OBSERVATIONS: Her right eye developed a second attack of posterior scleritis 3 months after the initial diagnosis. Twelve months after the first incident, granulomatous uveitis and sunset glow fundus were observed in both eyes. At the same time, lymphocytosis was found in the cerebrospinal fluid, and she was HLA DR-4-positive. In addition, poliosis was noted. CONCLUSIONS: The final diagnosis was primarily VKH disease with presenting signs and symptoms of unilateral posterior scleritis. We therefore recommend that when following a patient with posterior scleritis include VKH disease in the differential diagnosis.

Factors influencing the durability of the glucose-lowering effect of sitagliptin combined with a sulfonylurea.

We analyzed the changes of glycemic control over 12 months and the factors influencing blood glucose in 162 Japanese patients with type 2 diabetes having inadequate glycemic control despite sulfonylurea-based therapy who received add-on sitagliptin. Hemoglobin A1c (HbA1c) decreased significantly after 4 weeks of treatment, and this improvement was maintained for 1 year, although HbA1c was slightly higher in week 52 than in week 24. Comparison of the patients showing a ≥0.4% increase of HbA1c between weeks 24 and 52 (n = 57) with the others (n = 105) showed a significant difference in the change of bodyweight, as well as the dose of glibenclamide (both P < 0.01). Although combined therapy with sitagliptin and a sulfonylurea seems to be effective for at least 1 year, blood glucose levels are more likely to increase again in patients who show greater weight gain after 24 weeks of treatment and those receiving a higher dose of glibenclamide.

Safety comparison of additives in antiglaucoma prostaglandin (PG) analog ophthalmic formulations.

PURPOSE: To investigate the safety of five types of antiglaucoma prostaglandin analog ophthalmic formulations, and to clarify their differences in accordance with contained additives (preservatives and surface-active agents). METHODS: THE FOLLOWING FIVE TYPES OF OPHTHALMIC SOLUTIONS AND THREE TYPES OF ADDITIVES WERE INVESTIGATED: latanoprost (Xalatan(®); latanoprost), tafluprost (Tapros(®); tafluprost), bimatoprost (Lumigan(®); bimatoprost), travoprost (Travatan(®); travoprost), travoprost (Travatan Z(®); travoprost-Z), benzalkonium chloride (BAK), polyoxyethylene hardening castor oil 40 (HCO-40), and polysorbate 80 (P-80). These experimental solutions were exposed to the cultured cells of a rabbit-derived corneal cell line for a certain time, and the exposure time causing 50% cell damage (CD50), indicated by the ratio of viable cells to total cells was calculated (in vitro). In addition, corneal resistance (CR) was measured and CR ratio (post-treatment CR/pretreatment CR × 100) was calculated (in vivo). RESULTS: CD50 of each ophthalmic solution was the longest with tafluprost, followed by travoprost-Z, bimatoprost, travoprost, and latanoprost. CD50 of 0.005%, 0.01%, and 0.02% BAK was 14.5 minutes, 8.1 minutes, and 4.0 minutes, respectively. The number of viable cells decreased to 60%, 8 minutes after exposure with HCO-40, and 30 minutes after being exposed to P-80. The CR ratio was 81.0% with travoprost and 82.0% with latanoprost, indicating a significant posttreatment reduction of CR (P < 0.05). The CR ratio did not decrease after treatment with tafluprost, travoprost-Z, or bimatoprost. The CR ratio of 0.005%, 0.01%, and 0.02% BAK was 105.0%, 90.5%, and 68.7%, respectively, and that of HCO-40 and P-80 was 108.7% and 114.2%, respectively. CONCLUSION: BAK, HCO-40, and P-80 were thought to be involved in corneal injuries caused by each ophthalmic solution. Corneal injuries due to surface action were observed when using HCO-40 and P-80. When HCO-40 was combined with BAK, it induced micellar BAK and reduced corneal injuries by BAK.