Assessing the neurotoxicity of the carbamate methomyl in Caenorhabditis elegans with a multi-level approach.

The neurotoxicity and developmental effects of a widely applied insecticide (methomyl) was investigated by a multi-level approach (behavior and biometry, biochemical alterations and neurodegeneration) in Caenorhabditis elegans upon a short-term exposure (1 h) and a post-exposure period (48 h). The 1-h exposure to sub-lethal concentrations of methomyl (lower than 0.320 g L-1; i.e. below the estimated LC10) triggered significant changes on motor behavior and development impairment. The type of movement was significantly altered in methomyl-exposed worms, as well as biometric parameters (worms frequently idle and moving more backwards than controls; small body area, length and wavelength). These effects were followed by an increase of acetylcholine levels. Interestingly, after the 48-h recovery period, movement of previously exposed worms was similar to controls, and a concentration-dependent reversion of biometric endpoints was recorded, pointing out the transient action of the carbamate in line with an apparent absence of cholinergic neurons damage. This study provided new insight on the neurotoxicity of methomyl by showing that effects on movement and development were transient, and apparently did not result in neurodegeneration in cholinergic neurons. Moreover, these findings reinforced the advantages of using C. elegans in a multi-level approach for pesticide effects assessment.

Colorectal anastomosis after laparoscopic extended left colectomy: techniques and outcome.

AIM: After extended left colectomy, traditional colorectal anastomosis is often not feasible because of insufficient length of the remaining colon to perform a tension-free anastomosis. Total colectomy with ileorectal anastomosis could be an alternative but this can lead to unsatisfactory quality of life. Trans-mesenteric colorectal anastomosis or inverted right colonic transposition (the so-called Deloyers procedure) are two possible solutions for creating a tension-free colorectal anastomosis after extended left colectomy. Few studies have reported their results of these two techniques and mostly via laparotomy. The aim of this study was to describe the trans-mesenteric colorectal anastomosis and the inverted right colonic transposition procedure via a laparoscopic approach and report the outcome in a series of 13 consecutive patients. METHOD: This was retrospective chart review of laparoscopic colorectal surgery with trans-mesenteric colorectal anastomosis or the inverted right colonic transposition procedure from January 2015 up to 2019. An accompanying video demonstrates these two techniques. RESULTS: Thirteen consecutive patients underwent either a laparoscopic trans-mesenteric colorectal anastomosis (n = 9) or an inverted right colonic transposition procedure (n = 4). One patient had intra-operative presacral bleeding that was stopped successfully without conversion. Two patients had a postoperative intra-abdominal abscess, but no anastomotic complications were recorded. The median number of bowel movements per day after 6 months was 2 (range 2-5). CONCLUSIONS: Trans-mesenteric colorectal anastomosis or the inverted right colonic transposition procedure is feasible laparoscopically. The now well-established classical advantages of the laparoscopic approach are associated with good functional outcome after these procedures.

[Epidemic situation of imported malaria in Chengdu City from 2012 to 2016].

Objective To understand the malaria epidemic situation in Chengdu City, so as to provide the evidence for effectively carrying out the malaria elimination work. Methods The data of imported malaria in Chengdu City from 2012 to 2016 were collected from the Disease Surveillance Information Reporting System of Chinese Center for Disease Control and Prevention and analyzed respectively. Results A total of 240 imported malaria cases were reported in Chengdu City from 2012 to 2016. In detail, 68.75% of the cases were falciparum malaria cases, 20.41% were vivax malaria cases, 2.50% were quartan malaria cases, 6.25% were ovale malaria cases, and 2.08% were mixed Plasmodium infections. Among them three patients died, with a mortality of 1.25%. All of the cases were infected overseas, among which 224 patients returned from Africa and 16 patients from Southeast Asia. The annual average morbidity was 0.28/100 000, and there was a significantly difference among annual average morbidities (χ2 = 23.87, P < 0.001). There were malaria cases reported in every month, and no significantly difference among seasons (χ2 = 0.833, P > 0.05). Conclusion The number of overseas imported malaria in Chengdu City increases year by year. The effective measures to control the overseas imported malaria should be strengthened to consolidate the achievements of malaria elimination.

Increased expression of RRM2 by human papillomavirus E7 oncoprotein promotes angiogenesis in cervical cancer.

BACKGROUND: The purpose of this study was to confirm that RRM2 as a novel target of HPVE7 involved in cervical cancer angiogenesis. METHODS: Gene expression was analysed by RT-qPCR, western blot and immunohistochemistry in cervical cancer tissue and cell lines. Luciferase reporter assay was used to determine the activities of various RRM2 promoters. Secreted VEGF was measured by ELISA. RRM2-mediated capillary tube formation induced by HPVE7 in cervical cancer cells were evaluated using human umbilical vein endothelial cells in vitro. ROS induced by RRM2 in cercal cancer cells was confirmed by flow cytometry. The growth of cervical cancer cell overexpression RRM2 was examined by nude mouse xenograft. RESULTS: RRM2 as a novel downstream target for HPVE7 was upregulated by it at the transcriptional level through the E7-pRb interaction and binding of E2F to the RRM2 promoter region. Immunohistochemical analysis showed that the level of RRM2 positively correlated with the HPVE7 level in human cervical cancer. Functionally, overexpression of RRM2 enhanced the expression of HIF-1α and VEGF via activation of the ERK1/2 signalling pathway in cervical cancer cells, and significantly associated with increased microvessel densities in cervical cancer tissues. In vitro, HPVE7 stimulated RRM2-dependent capillary tube formation by HUVECs, and RRM2-enhanced angiogenesis was VEGF dependent. RRM2-activated ERK1/2 pathway was mediated through production of ROS. In the xenograft mouse model, overexpression of RRM2 in cervical cancer cells enhanced tumour growth as well as microvessel densities. CONCLUSION: HPVE7 induces upregulation of RRM2, which then promotes cervical carcinogenesis via ROS-ERK1/2-HIF-1α-VEGF-induced angiogenesis. Thus, the inhibition of RRM2 activity may be a novel therapeutic strategy for human cervical cancer.

Manganese induces p21 expression in PC12 cells at the transcriptional level.

Manganese is a common environmental and occupational pollutant. Excessive intake of manganese can cause toxicity known as manganism. Recently it has been demonstrated that unusual expression of cell cycle proteins and aberrant cell cycle progression in the central nervous system are involved in the pathogenesis of neurodegenerative diseases. The present studies were initiated to investigate whether p21 are induced after manganese exposure and its potential effects in vitro, with particular attention being given to understand the underlying regulatory mechanism of p21 induction by manganese in this process. We found that manganese induced DAergic cells injury and upregulation of p21 levels in nigrostriatal regions. Treatment of the PC12 cells with manganese resulted in a time- and concentration-dependent loss of cell viability. Analysis of cell cycle profile indicated that manganese blocked cell cycle progression by arresting the cell cycle at G2/M phase. Moreover, manganese treatment resulted in an increase in the mRNA and protein levels of p21, but did not have the same effect on other related factors. Silencing p21 by RNA interference showed a marked reversal of both G2/M arrest and the decrease in cell viability induced by manganese. Manganese did not stabilize the p21 protein and mRNA, and caused a marked increase in p21 mRNA levels together with an increase in its promoter activity, indicating a transcriptional mechanism. Overall, the in vivo and in vitro data suggest that exposure to manganese can increase p21 levels. An altered cell cycle status of PC12 cells can be induced by manganese through p21 up-regulation, and the induction of p21 occurs at the transcriptional level via promoter activation and mRNA induction.

Effects of tai chi exercise on posturography, gait, physical function and quality of life in postmenopausal women with osteopaenia: a randomized clinical study.

OBJECTIVE: to evaluate the effects of tai chi exercise on risk factors for falls in postmenopausal women with osteopaenia through measurements of balance, gait, physical function and quality of life. DESIGN: a randomized, controlled, single-blinded, 24-week trial with stratification by age and bone mass. SETTING: general community. PARTICIPANTS: Sixty-one independently living elderly females aged 65 years and older with low bone mass. INTERVENTIONS: subjects were recruited and randomly assigned to 24 weeks of tai chi (60 minutes/session, three sessions/week, n = 30) or a control group (n = 31). OUTCOME MEASURES: computerized dynamic posturography, gait, 'timed up and go', five-chair sit-to-stand and quality of life assessed at baseline, 12 and 24 weeks. RESULTS: after 24 weeks, subjects in the tai chi group demonstrated an increase in stride width (P = 0.05) and improvement in general health (P = 0.008), vitality (P = 0.02) and bodily pain (P = 0.03) compared with those in the control group. There was no significant difference in balance parameters, 'timed up and go', five-chair sit-to-stand and other domains of quality of life. CONCLUSION: tai chi exercise may reduce risk factors for falls by increasing the stride width, and may improve quality of life in terms of general health, vitality and bodily pain in postmenopausal women with osteopaenia.

Organic matter and nitrogen removal within field-scale constructed wetlands: reduction performance and microbial identification studies.

This study investigated organic matter and nitrogen reduction and transformation mechanisms within a field-scale hybrid natural purification system. The system included an oxidation pond, two serial surface-flow wetlands with a cascade in between, and a subsurface-flow wetland receiving secondary treated dormitory sewage. The average biochemical oxygen demand (BOD) and chemical oxygen demand (COD) removal was 81 and 48%, respectively. Microbial degradation was the primary process contributing to organic reduction. Total Kjeldahl nitrogen (TKN) and ammonium decreased from 7.1 to 3.9 and 5.58 to 3.25 mg/L, respectively, within the surface-flow wetlands. The results indicated that nitrification occurred within the aerobic compartments. The nitrate levels continued to decrease from 1.26 to 1.07 mg/L, indicating nitrate reduction occurred in the surface-flow wetland. Total nitrogen decreased from 8.61 to 5.12 mg/L, equivalent to a 41% reduction, within the surface-flow wetlands. Results revealed that denitrification might concurrently occur in the compartment of surface-flow wetland. Total nitrogen continued to decrease from 5.12 to 3.99 mg/L within the anoxic subsurface-flow wetlands through denitrification transformation. The significant total nitrogen reduction observed was 65%. The predominant reduction of total nitrogen might take place within the sediment of surface flow and the subsurface-flow wetland where denitrification occurred. The microbial identification results also indicated that nitrification/denitrification might occur concurrently within the sediments of surface-flow wetlands. The results of this study show that hybrid wetland systems are a viable option for organic matter and nitrogen transformation and removal in tropical regions where tertiary wastewater systems are too costly or unable to operate. Treated water from these systems can comply with local surface water criteria rendering water for reuse and groundwater recharge.

Green tea polyphenols and Tai Chi for bone health: designing a placebo-controlled randomized trial.

BACKGROUND: Osteoporosis is a major health problem in postmenopausal women. Evidence suggests the importance of oxidative stress in bone metabolism and bone loss. Tea consumption may be beneficial to osteoporosis due to its antioxidant capability. However, lack of objective data characterizing tea consumption has hindered the precise evaluation of the association between tea ingestion and bone mineral density in previous questionnaire-based epidemiological studies. On the other hand, although published studies suggest that Tai Chi (TC) exercise can benefit bone health and may reduce oxidative stress, all studies were conducted using a relatively healthy older population, instead of a high-risk one such as osteopenic postmenopausal women. Therefore, this study was designed to test an intervention including green tea polyphenol (GTP) and TC exercise for feasibility, and to quantitatively assess their individual and interactive effects on postmenopausal women with osteopenia. METHODS/DESIGN: One hundred and forty postmenopausal women with osteopenia (defined as bone mineral density T-score at the spine and/or hip between 1 to 2.5 SD below the reference database) were randomly assigned to 4 treatment arms: (1) placebo group receiving 500 mg medicinal starch daily, (2) GTP group receiving 500 mg of GTP per day, (3) placebo+TC group receiving both placebo treatment and TC training (60-minute group exercise, 3 times per week), and (4) GTP+TC group receiving both GTP and TC training for 24 weeks. The outcome measures were bone formation biomarker (serum bone alkaline phosphatase), bone resorption biomarker (serum tartrate resistant acid phosphatase), and oxidative DNA damage biomarker (urinary 8-hydroxy-2'-deoxyguanosine). All outcome measures were determined at baseline, 4, 12, and 24 weeks. Urinary and serum GTP concentrations were also determined at baseline, 4, 12, and 24 weeks for bioavailability. Liver function was monitored monthly for safety. A model of repeated measurements with random effect error terms was applied. Traditional procedures such as ANCOVA, chi-squared analysis, and regression were used for comparisons. DISCUSSION: We present the rationale, design, and methodology of a placebo-controlled randomized trial to investigate a new complementary and alternative medicine strategy featuring a dietary supplement and a mind-body exercise for alleviating bone loss in osteopenic postmenopausal women.

Group and home-based tai chi in elderly subjects with knee osteoarthritis: a randomized controlled trial.

OBJECTIVE: To evaluate the effects of tai chi consisting of group and home-based sessions in elderly subjects with knee osteoarthritis. DESIGN: A randomized, controlled, single-blinded 12-week trial with stratification by age and sex, and six weeks of follow-up. SETTING: General community. PARTICIPANTS: Forty-one adults (70 +/- 9.2 years) with knee osteoarthritis. INTERVENTIONS: The tai chi programme featured six weeks of group tai chi sessions, 40 min/session, three times a week, followed by another six weeks (weeks 7 -12) of home-based tai chi training. Subjects were requested to discontinue tai chi training during a six-week follow-up detraining period (weeks 13-18). Subjects in the attention control group attended six weeks of health lectures following the same schedule as the group-based tai chi intervention (weeks 0 -6), followed by 12 weeks of no activity (weeks 7-18). MAIN OUTCOME MEASURES: Knee pain measured by visual analogue scale, knee range of motion and physical function measured by Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) were recorded at baseline and every three weeks throughout the 18-week study period. Data were analysed using a mixed model ANOVA. RESULTS: The six weeks of group tai chi followed by another six weeks of home tai chi training showed significant improvements in mean overall knee pain (P = 0.0078), maximum knee pain (P = 0.0035) and the WOMAC subscales of physical function (P = 0.0075) and stiffness (P = 0.0206) compared to the baseline. No significant change of any outcome measure was noted in the attention control group throughout the study. The tai chi group reported lower overall pain and better WOMAC physical function than the attention control group at weeks 9 and 12. All improvements disappeared after detraining.

A mutant alpha-amylase with only part of the catalytic domain and its structural implication.

A truncated mutant alpha-amylase, Xa-S2, was obtained from Xanthomonas campestris wild type alpha-amylases (Xa-WT) through random mutagenesis that contained 167 amino acid residues (approx 65% shorter than that of Xa-WT). Secondary structure prediction implied that Xa-S2, would be unable to form the whole (beta/alpha)(8)-barrel catalytic domain and did not have the three conserved catalytic residues of wild type alpha-amylase, but it still displays the starch-hydrolyzing activity. Xa-S2 was prepared, characterized and compared to the recombinant wild-type enzymes. The K (m) for starch was 32 mg/ml; activity was optimal at pH 6.2 and 30 degrees C. In contrast, the K (m) for starch of Xa-WT was 8 mg/ml and optimal enzyme activity was at pH 6.0-6.2 and 45-50 degrees C. Our results suggested that Xa-S2 is a new amylase with a minimal catalytic domain for hydrolyzing substrates with of alpha-1,4-glucosidic bonds.

In vitro mutagenesis of Xanthomonas campestris alpha-amylase gene by partially replacing deoxythymidine triphosphate with 5-bromo-2'-deoxyuridine-5'-triphosphate using a PCR technique.

Three mutants of the wild type alpha-amylase gene from Xanthomonas campestris pv. campestris 8004 were obtained using a PCR technique in which deoxythymidine triphosphate (dTTP) was partially replaced by 5-bromo-2'-deoxyuridine-5'-triphosphate (BrdUTP), at an optimal dTTP:BrdUTP ratio of 1000:1. Of thre three mutants that were obtained and which were sequenced, one mutant with 40 times higher activity than the wild type alpha-amylase gene product was obtained by using primary PCR products as a template for a second PCR reaction.

Suppression of post-vitrectomy lens changes in the rabbit by novel benzopyranyl esters and amides.

This study reports for the first time a therapeutic modality for the suppression of posterior subcapsular cataract (PSC) formation in an animal model (rabbit) of vitrectomy. This therapeutic modality may also have the potential to attenuate/prevent the high incidence of loss of vision due to cataract formation in patients that undergo vitrectomy. Unilateral, partial vitrectomy was performed on 2.5 month old Dutch Belted rabbits with vitreous replaced by either commercially available BSS((R)) or BSS PLUS((R)) (n=16). Alternatively, vitreous was replaced with a proprietary, modified BSS PLUS((R)) irrigating solution containing 1.25 microM AL-8417 (n=12), 5.0 microM AL-12615 (n=5) or 5.0 microM AL-17052 (n=9). Age matched, non-operated rabbits were used as controls (n=16). Lenses were analysed by correlative structural (light, scanning electron microscopic and three-dimensional computer-assisted drawings) and optical (low power helium-neon laser scan) quality analysis 6 months following surgery. Results demonstrate that vitreous replacement with an irrigating solution that contains the ester-linked benzopyran, AL-8417, the amide-linked benzopyran pro-drug, AL-17052, or its active metabolite, AL-12615, prevented abnormal post-vitrectomy lens growth, or fiber formation. Focal length variability (FLV) assessments (sharpness of focus) confirmed the beneficial drug effects detected morphologically, with FLV being essentially equal to that of age-matched, non-surgical controls. In contrast, lenses of animals with vitreous replaced solely with BSS((R)) or BSS PLUS((R)) exhibited significantly higher FLV than both age-matched controls and animals that underwent vitrectomy with drug-containing irrigating solutions. The ability of AL-8417, AL-17052 and its active metabolite, AL-12615, to suppress vitrectomy-induced posterior lens fiber changes appears to reside in their unique pharmacological profile, acting as antioxidant, anti-inflammatory and cytostatic agents.

Ocular bioavailability of ciprofloxacin in sustained release formulations.

A novel sustained release delivery system of ciprofloxacin for the eye was developed. The system consists of a viscosity enhancer (carbopol gel or hydroxypropylmethylcellulose solution) plus a penetration enhancer (dodecylmaltoside) to overcome penetration barriers and loss due to wash-out and thus achieve the desired ciprofloxacin ocular absorption. The present studies were designed to assess the ocular penetration and bioavailability of ciprofloxacin in sustained release formulations. In vitro studies in rabbits indicated an approximate 10-fold increase in drug penetration through the rabbit cornea using the penetration enhancer, dodecylmaltoside. In vivo bioavailability studies demonstrate that these formulations provided a long drug duration in the cornea. After administration of a single topical dose of ciprofloxacin (0.3%/30 microL), corneal levels greater than the Minimum Inhibitory Concentration (MIC90) (0.5 microg/g) were observed through eight hours. These sustained release formulations delivered 10-fold more drug into the aqueous humor than the standard solution formulation. Maximum ciprofloxacin concentrations in the aqueous humor (0.5-0.7 microg/mL) were attained between one and two hours after dosing. Using these sustained release formulations, ciprofloxacin can penetrate to the anterior chamber of the eye in concentrations that are inhibitory for most gram-negative and gram-positive organisms. These topical ocular formulations have prophylactic utility for prevention of post-surgical infection, offering greater efficacy and safety than currently available treatments.

The effectiveness of tobramycin and Ocuflox in a prophylaxis model of Staphylococcus keratitis.

PURPOSE: To determine the effectiveness of prophylactic antibiotic treatment prior to intra-corneal infection with Staphylococcus aureus. METHODS: One topical drop of Tobrex (0.3% tobramycin), tobramycin (0.3%) in the Tobrex vehicle with 0.05% dodecyl maltoside (DDM)/4.0% hydroxypropylmethycellulose (HPMC), Ocuflox (0.3% ofloxacin) or DDM/HPMC vehicle were applied to rabbit eyes at one or five hours prior to injection of bacteria. Approximately 500 colony-forming units (CFU) of S. aureus strain 8325-4 were injected into the corneal stroma. Rabbits were sacrificed five hours after infection and corneal homogenates were cultured to determine the number of colony forming units (CFU) per cornea. RESULTS: Rabbits treated at five hours prior to infection with tobramycin-DDM/HPMC reduced the bacterial load by approximately 2.4 log CFU/cornea as compared to the untreated control (3.47 +/- 0.98 vs. 5.71 +/- 0.14 log CFU/cornea, respectively; P = 0.0010); however, Ocuflox, Tobrex, or DDM/HPMC vehicle did not significantly reduce the log CFU (P >or= 0.4837). Rabbits treated at 1 hour prior to infection with Ocuflox or tobramycin-DDM/HPMC had significantly reduced CFU/cornea (1.31 +/- 0.86 and 0.48 +/- 0.31 log CFU/cornea, respectively) as compared to the untreated group (5.71 +/- 0.14 log CFU/cornea; P or= 0.2312). CONCLUSIONS: This pre-treatment model of Staphylococcus keratitis quantitatively measured the prophylactic effectiveness of topical antibiotic formulations. An important finding was that a tobramycin-DDM/HPMC formulation was highly effective as a prophylactic medication.

Nepafenac, a unique nonsteroidal prodrug with potential utility in the treatment of trauma-induced ocular inflammation: II. In vitro bioactivation and permeation of external ocular barriers.

Nepafenac, the amide analog of the NSAID amfenac, was examined in vitro for its bioactivation by ocular tissue components and its ability to permeate external ocular barriers. Rabbit tissues catalyzed a concentration-dependent conversion of nepafenac to amfenac. The order of specific hydrolytic activity is retina/choroid >> iris/ciliary body. Corneal tissue showed only minimal activity. Similarly, in human ocular cadaver tissue the specific activity of iris/ciliary body was greater than cornea. Continued perfusion of the corneal epithelium demonstrated a nearly six-fold greater permeation coefficient for nepafenac (k(p) = 727 x 10(-6) min(-1)) than for diclofenac (k(p) = 127 x 10(-6) min(-1)). Superior permeation of conjunctival and scleral tissue by nepafenac (k(p) = 128 x 10(-6) min(-1)) compared to diclofenac (k(p) = 80 x 10(-6) min(-1)) was also evident. Short term perfusion (5 min) of the corneal surface with 0.1% nepafenac resulted in sustained flux of drug across the cornea for 6 h. Under identical conditions only 3.3 microM of diclofenac accumulated on the corneal endothelial side compared to 16.7 microM nepafenac. The enhanced permeability of nepafenac, combined with rapid bioactivation to amfenac by the iris/ciliary body and retina/choroid, make it a target specific NSAID for inhibiting prostaglandin formation in the anterior and posterior segments of the eye.

Age-related permeability changes in rabbit corneas.

The present study was designed to determine whether the corneal penetration of test compounds is altered in aging. Experiments were carried out by means of passive transport under steady-state conditions using in vitro diffusion cells. Permeabilities of a variety of compounds with different physicochemical properties were measured in young (six weeks) and old (three to four years) intact and denuded (wounded) rabbit corneas. There was a marked difference in penetration of compounds between young and aged corneas. A significant decrease in permeability with age was observed. The degree of difference depended on the lipophilicity and molecular weight of the compound and the integrity of the epithelial cell layer. The difference was more pronounced for large hydrophilic than small lipophilic compounds in the intact corneas. The difference in permeabilities of test compounds between young and old denuded corneas was essentially the same (about 2-fold). These studies provide clues to the fundamental biochemical difference in young and old corneas and better enables the development of rationales for efficient drug and nutrient delivery across the cornea.

Molecular-modeling calculations of enzymatic enantioselectivity taking hydration into account.

A new molecular-modeling methodology has been applied to explain enzymatic enantioselectivity in water. This methodology, which combines vacuum molecular mechanics and the continuum solvation method, should provide a more realistic view of the solvent-enzyme and solvent-substrate interactions than the heretofore used approaches involving the vacuum molecular mechanics only. The methodology described herein has been validated using the experimental data on alpha-chymotrypsin's enantioselectivity in the hydrolysis of four chiral substrates. The reasons why the vacuum molecular mechanics, although not taking hydration into account, still in most cases provide a satisfactory approximation of reality are discussed.

On enzymatic activity in organic solvents as a function of enzyme history.

Catalytic activities of alpha-chymotrypsin and subtilisin Carlsberg in various hydrous organic solvents were measured as a function of how the enzyme suspension had been prepared. In one method, lyophilized enzyme was directly suspended in the solvent containing 1% water. In another, the enzyme was precipitated from its aqueous solution by a 100-fold dilution with an anhydrous solvent. In most cases, the reaction rate in a given nonaqueous enzymatic system strongly (up to an order of magnitude) depended on the mode of enzyme preparation. The magnitude of this dependence was markedly affected by the nature of the solvent and enzyme. A mechanistic hypothesis proposed to explain the observed dependencies was verified in additional experiments in which the water contents and enzyme history were further varied.

[A self-made corneal graft marker made from disposable trephine].

A homemade corneal marker was contrived from a Pharmacia Superblade disposable corneal trephine by cutting away one arm of the trephine and then bending the single remaining arm to an angle of 45 degrees to the handle. The radii of the trephines ranged from 6.5mm to 8.5mm, at successive increments of 0.25mm. In optical corneal grafts, this marker can be used to pinpoint the center of the cornea, thus providing more accurate centralization of the area to be grafted. In therapeutic corneal grafts, the marker provides a more accurate determination of the most suitable area to be grafted. Unnecessary removal of healthy tissue or incomplete removal of diseased tissue are thus avoided. This marker is made easily and at no additional expense, and show itself to be a useful instrument to accurately determine the graft area in corneal surgery.