Estimating pregnancy rate from blubber progesterone levels of a blindly biopsied beluga population poses methodological, analytical and statistical challenges.

Beluga (Delphinapterus leucas) from the St. Lawrence Estuary, Canada, have been declining since the early 2000s, suggesting recruitment issues as a result of low fecundity, abnormal abortion rates or poor calf or juvenile survival. Pregnancy is difficult to observe in cetaceans, making the ground truthing of pregnancy estimates in wild individuals challenging. Blubber progesterone concentrations were contrasted among 62 SLE beluga with a known reproductive state (i.e. pregnant, resting, parturient and lactating females), that were found dead in 1997 to 2019. The suitability of a threshold obtained from decaying carcasses to assess reproductive state and pregnancy rate of freshly-dead or free-ranging and blindly-sampled beluga was examined using three statistical approaches and two data sets (135 freshly harvested carcasses in Nunavik, and 65 biopsy-sampled SLE beluga). Progesterone concentrations in decaying carcasses were considerably higher in known-pregnant (mean ± sd: 365 ± 244 ng g-1 of tissue) than resting (3.1 ± 4.5 ng g-1 of tissue) or lactating (38.4 ± 100 ng g-1 of tissue) females. An approach based on statistical mixtures of distributions and a logistic regression were compared to the commonly-used, fixed threshold approach (here, 100 ng g-1) for discriminating pregnant from non-pregnant females. The error rate for classifying individuals of known reproductive status was the lowest for the fixed threshold and logistic regression approaches, but the mixture approach required limited a priori knowledge for clustering individuals of unknown pregnancy status. Mismatches in assignations occurred at lipid content < 10% of sample weight. Our results emphasize the importance of reporting lipid contents and progesterone concentrations in both units (ng g-1 of tissue and ng g-1 of lipid) when sample mass is low. By highlighting ways to circumvent potential biases in field sampling associated with capturability of different segments of a population, this study also enhances the usefulness of the technique for estimating pregnancy rate of free-ranging population.

Geometric Morphometric Assessment of Toe Shape in Forest and Urban Lizards Following Hurricane Disturbances.

Evidence suggests that hurricanes can influence the evolution of organisms, with phenotypic traits involved in adhesion, such as the toepads of arboreal lizards, being particularly susceptible to natural selection imposed by hurricanes. To investigate this idea, we quantified trait variation before and after Hurricanes Irma and Maria (2017) in forest and urban populations of the Puerto Rican lizard Anolis cristatellus. We found that the hurricanes affected toe morphology differently between forest and urban sites. In particular, toepads of the forefeet were longer and narrower in forest, but wider in urban populations, compared to pre-hurricane measures. Toepads of the hind feet were larger in area following the hurricanes. Fore and rear toes increased in length following the hurricane. There were no changes in the number of lamellae scales or lamellae spacing, but lamellae 6-11 of the forefeet shifted proximally following the hurricane. We also measured clinging performance and toe shape. We found that toepad area and toe lengths were stronger predictors of adhesive forces than toepad shape. Our results highlight an interaction between urbanization and hurricanes, demonstrating the importance to consider how urban species will respond to extreme weather events. Additionally, our different results for fore and rear feet highlight the importance of evaluating both of these traits when measuring the morphological response to hurricanes in arboreal lizards.

La evidencia sugiere que los huracanes pueden influir en la evolución de los organismos, rasgos fenotípicos como las almohadillas distales de los lagartos arbóreos, son particularmente susceptibles a la selección natural impuesta por los huracanes. Para investigar esta idea, cuantificamos la variación de las almohadillas distales antes y después de los huracanes Irma y María (2017) en poblaciones de bosques y urbanas de las lagartijas puertorriqueña Anolis cristatellus. Encontramos que los cambios morfológicos luego de los huracanes variaron entre las poblaciones de bosque y urbanas. Para las poblaciones de bosque, las almohadillas de las patas delanteras eran más largas y estrechas luego de las tormentas. Por el contrario, las almohadillas delanteras de las poblaciones urbanas fueron más anchas luego de los huracanes. Las almohadillas de los pies traseros tenían un área más grande en todas las poblaciones luego de los huracanes. Los dedos delanteros y traseros aumentaron de longitud después del huracán. No hubo cambios en el número de escamas en las almohadillas distales ni en el ancho de estas escamas, pero las escamas 6­11 de las patas delanteras se desplazaron proximalmente después del huracán. También medimos las fuerzas adhesivas producida por las almohadillas distales para contrastar con la morfología de los dedos. Encontramos que el área de las almohadillas distales y la longitud de los dedos fueron los predictores más fuertes de las fuerzas adhesivas. Nuestros resultados destacan una interacción entre la urbanización y los huracanes, lo que demuestra la importancia de considerar cómo responderán las especies urbanas a los eventos climáticos extremos. Además, nuestros diferentes resultados para las patas delanteras y traseras resaltan la importancia de evaluar ambos rasgos al medir la respuesta morfológica a los huracanes en lagartijas arbóreos.

Anticipating Urinary Retention Following Total Hip and Total Knee Replacements.

INTRODUCTION: Urinary retention is a widely recognised postoperative complication. Although anecdotally lower limb arthroplasty is linked with high rates of urinary retention, there are no current accepted standards for determining which patients are at higher risk and should therefore be offered intra operative catheterisation. MATERIALS AND METHODS: One hundred patients, 55 females and 45 males, who underwent uncomplicated total hip or total knee replacements at Furness General Hospital were recruited between January and April 2017. RESULTS: Post-operative urinary retention was seen frequently, with 38 patients (38%) requiring post-operative catheterisation. Twenty-one males (46%) developed postoperative retention compared to 17 (30%) of females, representing a statistically significant increase in risk seen in male patients. (p 0.009). Post-operative urinary retention requiring catheterisation was associated with increasing age, with those over 75 years having a significantly higher risk than those less than 75 years irrespective of gender (p 0.04). There was no significant difference in urinary retention rates between patients who had general (n=21) or spinal anaesthetic (n=79) with 33% of GA patients and 39% of spinal anaesthetic patients requiring catheterisation (p 0.17). CONCLUSION: There are increased rates of urinary retention seen in lower limb arthroplasty patients than those described in the general surgical population, with male patients and all those over 75 years of age having a significantly higher risk. Clinically, it may therefore be sensible to consider offering routine intra operative catheterisation to this cohort of patients.

Anticipating Urinary Retention Following Total Hip and Total Knee Replacements

@#Introduction: Urinary retention is a widely recognised postoperative complication. Although anecdotally lower limb arthroplasty is linked with high rates of urinary retention, there are no current accepted standards for determining which patients are at higher risk and should therefore be offered intra operative catheterisation. Materials and Methods: One hundred patients, 55 females and 45 males, who underwent uncomplicated total hip or total knee replacements at Furness General Hospital were recruited between January and April 2017. Results: Post-operative urinary retention was seen frequently, with 38 patients (38%) requiring post-operative catheterisation. Twenty-one males (46%) developed postoperative retention compared to 17 (30%) of females, representing a statistically significant increase in risk seen in male patients. (p 0.009). Post-operative urinary retention requiring catheterisation was associated with increasing age, with those over 75 years having a significantly higher risk than those less than 75 years irrespective of gender (p 0.04). There was no significant difference in urinary retention rates between patients who had general (n=21) or spinal anaesthetic (n=79) with 33% of GA patients and 39% of spinal anaesthetic patients requiring catheterisation (p 0.17). Conclusion: There are increased rates of urinary retention seen in lower limb arthroplasty patients than those described in the general surgical population, with male patients and all those over 75 years of age having a significantly higher risk. Clinically, it may therefore be sensible to consider offering routine intra operative catheterisation to this cohort of patients.

Performance and nitrogen use efficiency in mid-lactation dairy cows fed timothy cut in the afternoon or morning.

Shifting cutting from morning to afternoon has been shown to increase the concentration of nonstructural carbohydrates in forages. We hypothesized that, compared with a total mixed ration containing timothy baleage and silage cut in the morning (a.m.-cut TIM), a total mixed ration containing timothy baleage and silage cut in the afternoon (p.m.-cut TIM) would improve animal performance and N use efficiency in mid-lactation Holstein cows due to enhanced supply of ruminal fermentable energy. The objective of this study was to compare the effects of p.m.- versus a.m.-cut TIM on milk yield, concentrations and yields of milk components, ruminal metabolism, and plasma concentrations of AA in mid-lactation Holstein cows. Ten (6 ruminally cannulated) primiparous cows averaging 139±13 d in milk and 550±56 kg of body weight, and 6 (2 ruminally cannulated) multiparous cows averaging 128±11 d in milk and 632±57 kg of body weight at the beginning of the experiment, were used in a crossover design. Each period lasted 21 d with 14 d for diet adaptation and 7 d for data and sample collection. The concentration of nonstructural carbohydrates (water-soluble carbohydrates plus starch) was numerically greater in the p.m.- versus the a.m.-cut TIM and averaged 13.2±1.06% and 12.2±1.13%, respectively. Treatment × parity effects were observed for milk urea N, feed efficiency, and milk N efficiency, whereas parity effects were observed for nutrient intake, milk yield, and plasma concentration of several essential and nonessential AA. Intakes of dry matter (19.3 versus 18.6 kg/d) and nonstructural carbohydrates (2.56 versus 2.31 kg/d), and yields of 4% fat-corrected milk (23.1 versus 22.2 kg/d), energy-corrected milk (25.0 versus 24.1 kg/d), milk fat (0.91 versus 0.88 kg/d), and milk protein (0.77 versus 0.73 kg/d) were all greatest with feeding p.m.-cut TIM. Milk yield (23.5 versus 22.7 kg/d) tended to increase in cows fed p.m.-cut TIM. The ruminal fermentation profiles and plasma concentrations of AA were mostly unaffected by treatments. However, ruminal valerate (1.01 versus 1.17 mol/100 mol) and plasma Gly (172 versus 188 µM) were lowest with feeding p.m.-cut TIM. Overall, feeding mid-lactation dairy cows a total mixed ration that consisted of p.m.-cut timothy baleage and silage significantly increased dry matter intake and yields of milk, milk fat, and milk protein.

Alfalfa baleage with increased concentration of nonstructural carbohydrates supplemented with a corn-based concentrate did not improve production and nitrogen utilization in early lactation dairy cows.

The objective of this study was to investigate the effects of feeding alfalfa baleage with different concentrations of nonstructural carbohydrates (NSC) supplemented with a common corn-based concentrate on performance, ruminal fermentation profile, N utilization, and omasal flow of nutrients in dairy cows during early lactation. Ten multiparous (8 ruminally cannulated) and 8 primiparous Holstein cows were randomly assigned to treatments (high- or low-NSC diet) in a crossover design. The difference in NSC concentration between the 2 alfalfa baleages fed from d14 to 21 averaged 14 g of NSC/kg of dry matter (DM). Forages and concentrate were offered in separate meals with forages fed once and concentrate offered 3 times daily. Except for the molar proportion of valerate, which was lowest in cows fed the high-NSC diet, no other changes in ruminal fermentation were observed. Omasal flows of most nitrogenous fractions, including bacterial nonammonia N and AA, were not affected by treatments. Apparent ruminal digestibilities of neutral and acid detergent fiber and N were lowest, whereas that of total ethanol-soluble carbohydrates was highest when feeding the high-NSC diet. Postruminal digestibilities of DM, organic matter, fiber, and N were highest in cows fed the high-NSC diet, resulting in no difference in total-tract digestibilities. Total-tract digestibility of total ethanol-soluble carbohydrates was highest in cows fed the high-NSC diet, but that of starch did not differ across treatments. Although milk yield and total DM intake did not differ between treatments, yields of milk fat and 4% fat-corrected milk decreased significantly in cows fed the high-NSC diet. Milk concentration of urea N was lowest, and that of ruminal NH3-N highest, in cows fed the high-NSC diet. Plasma urea N concentration tended to be decreased in cows fed the high-NSC diet, but concentrations of AA were not affected by treatments, with the exception of Asp and Cys, both of which were lowest in cows fed the low-NSC diet. Feeding diets with contrasting NSC concentrations did not improve milk production, N utilization, or bacterial protein synthesis, possibly because intakes of NSC and DM were similar between treatments. Overall, results from the current study should be interpreted cautiously because of the lack of difference in dietary NSC intake between treatments and reduced N and fiber intakes when feeding the high-NSC diet.

Effects of nonstructural carbohydrate concentration in alfalfa on fermentation and microbial protein synthesis in continuous culture.

Insufficient readily fermentable energy combined with extensive degradation of proteins in alfalfa (Medicago sativa L.) may result in poor forage N utilization by ruminants. Using the inherent genetic variability and differences between harvests, our objective was to compare the effect of contrasting concentrations of nonstructural carbohydrates (NSC) in alfalfa on rumen fermentation and microbial protein synthesis. Individual genotypes of the alfalfa cultivar AC Caribou grown near Québec City, Québec, Canada, were harvested at the vegetative and early flowering stages, dried at 55 degrees C, ground, and analyzed for soluble carbohydrates (fructose + sucrose + glucose + pinitol) and starch. Approximately 20 genotypes having, respectively, the highest and lowest NSC concentrations were pooled to constitute 2 contrasted 1-kg forage samples. Samples of high- (17.9% DM) and low- (7.4% DM) NSC alfalfa were respectively allocated to separate dual-flow fermenters in a completely randomized design with 3 replications. Rumen inoculum was obtained from 4 ruminally fistulated cows in early lactation that were fed a TMR with a 50:50 forage to concentrate ratio. A 10-d incubation period was used, with the first 6 d serving as an adaptation period followed by 4 d of sampling with solid and liquid dilution rates in the fermenters set at approximately 2.0 and 4.3%/h, respectively. High versus low NSC concentration in alfalfa significantly enhanced the apparent digestibility of OM (59.1% for high-NSC alfalfa vs. 54.4% for low-NSC alfalfa) and DM (60.0 vs. 54.3%) and the true digestibility of DM (74.1 vs. 64.7%). Increasing NSC concentration in alfalfa (high vs. low) significantly decreased ruminal pH (6.85 vs. 7.08) and NH(3)-N concentration (26.0 vs. 33.6 mg/dL) and increased total VFA concentration (94.9 vs. 83.0mM). Molar proportions of acetate, isobutyrate, and isovalerate significantly decreased, whereas molar proportions of propionate and butyrate significantly increased with high-NSC alfalfa, resulting in a more glucogenic fermentation. More importantly, microbial N flow (263 vs. 230 mg/d) and bacterial N efficiency (41.1 vs. 29.6% of available N), measured using (15)N as a microbial marker, both significantly increased with the high-NSC alfalfa. These results indicate that increasing the concentration of NSC in alfalfa promotes a glucogenic fermentation and enhances microbial N synthesis in the rumen.

Near-infrared reflectance spectroscopy prediction of neutral detergent-soluble carbohydrates in timothy and alfalfa.

Carbohydrates in forage crops can be divided into neutral detergent-insoluble fiber and neutral detergent-soluble carbohydrates (NDSC); the latter includes organic acids (OA), total ethanol:water-soluble carbohydrates (TESC), starch, and neutral detergent-soluble fiber (NDSF). The accurate and efficient estimation of NDSC in forage crops is essential for improving the performance of dairy cattle. In the present study, visible and near-infrared reflectance spectroscopy (NIRS) were applied to evaluate the feasibility of predicting OA, TESC, starch, NDSF, NDSC, and all related constituents used to calculate these 5 carbohydrate fractions in timothy and alfalfa. Forage samples (n = 1,008) of timothy and alfalfa were taken at the first and second harvests at 2 sites in 2007; samples were dried, ground, and then scanned (400 to 2,500 nm) using an NIRSystems 6500 monochromator. A calibration (n = 60) and a validation (n = 15) set of samples were selected for each species and then chemically analyzed. Concentrations of TESC and NDSC in timothy, as well as starch in alfalfa, were successfully predicted, but many other carbohydrate fractions were not predicted accurately when calibrations were performed using single-species sample sets. Both sets of samples were combined to form new calibration (n = 120) and validation (n = 30) sets of alfalfa and timothy samples. Calibration and validation statistics for the combined sets of alfalfa and timothy samples indicated that TESC, starch, and NDSC were predicted successfully, with coefficients of determination of prediction of 0.92, 0.89, and 0.93, and a ratio of prediction to deviation (RPD) of 3.3, 3.1, and 3.6, respectively. The NDSF prediction was classified as moderately successful The NIRS prediction of OA was unsuccessful All related constituents were predicted successfully by NIRS except ethanol-insoluble residual OM, with Our results confirm the feasibility of using NIRS to predict NDSC, its fractions, and other related constituents, except for OA and ethanol-insoluble residual OM, in timothy and alfalfa forage samples.

Alfalfa cut at sundown and harvested as baleage increases bacterial protein synthesis in late-lactation dairy cows.

Alfalfa (Medicago sativa L.) cut at sundown (p.m.) has been shown to have a greater concentration of total nonstructural carbohydrates (TNC) than when cut at sunup (a.m.). Eight ruminally cannulated Holstein cows that were part of a larger lactation trial were used in a crossover design (24-d periods) to investigate the effects of alfalfa cutting time on digestibility and omasal flow of nutrients. Alfalfa was cut at sundown or sunup, field-wilted, and harvested as baleage (530 +/- 15.0 g of dry matter/kg of fresh matter). The difference in TNC concentration between p.m. and a.m. alfalfa within each pair of bales fed daily during the 10 d of data and sample collection varied from -10 to 50 g/ kg of dry matter. Each pair of bales was fed for ad libitum intake to cows once daily with no concentrate. During the 3 d of omasal sampling, intake (+0.8 kg/d) and omasal flow of organic matter (OM; +0.42 kg/d) tended to be greater when cows were fed p.m. vs. a.m. alfalfa, but no differences were found for ruminal and postruminal digestion of this nutrient. Similarly, N apparently digested ruminally and postruminally did not differ when feeding p.m. vs. a.m. alfalfa. However, N truly digested in the rumen, as a proportion of N intake, was significantly greater in cows fed p.m. (79%) vs. a.m. alfalfa (74%), thus suggesting that longer wilting time of alfalfa cut at sundown increased forage proteolysis. Supply of rumen-degradable protein did not change (2,716 g/d) when averaged across treatments, whereas omasal flow of non-NH(3) nonbacterial N was significantly decreased (-29 g/d) when feeding p.m. vs. a.m. alfalfa. Omasal flow of total bacterial non-NH(3)-N (NAN) increased (+21 g/d) significantly when cows were fed p.m. vs. a.m. alfalfa possibly because bacteria from cows fed p.m. alfalfa captured significantly more NH(3) than those from cows fed a.m. alfalfa. Therefore, greater availability of fermentable energy as TNC appears to increase the capacity of microbes to uptake NH(3)-N and convert it to microbial protein. Enhanced OM intake can also explain the observed increase in bacterial protein synthesis with p.m. alfalfa. Efficiency of bacterial protein synthesis, expressed on a fermented OM basis or as grams of bacterial NAN per gram of rumen-degradable N, did not differ between p.m. and a.m. alfalfa. Conversely, bacterial efficiency, as grams of bacterial NAN per gram of N intake, was significantly increased when cows were fed p.m. baleage. No significant difference between forage treatments was found for the omasal flow of total AA from omasal true digesta, suggesting no benefit of daytime cutting management on the passage of total AA to the lower gastrointestinal tract. Enhancing energy intake and TNC concentration of alfalfa by shifting forage cutting from sunup to sundown increased protein synthesis and NH(3) uptake by ruminal bacteria indicating an improvement in N utilization.

Alfalfa cut at sundown and harvested as baleage improves milk yield of late-lactation dairy cows.

Alfalfa (Medicago sativa L.) cut at sundown has been shown to contain greater concentration of total nonstructural carbohydrates (TNC) than that cut at sunup. Fourteen multiparous (8 ruminally cannulated) and 2 primiparous lactating dairy cows were randomly assigned to 2 treatments in a crossover design (2 periods of 24 d) to investigate the effects of alfalfa daytime cutting management on ruminal metabolism, nutrient digestibility, N balance, and milk yield. Half of each alfalfa field (total of 3 fields) was cut at sundown (PM) after a sunny day, whereas the second half was cut at sunup (AM) on the following day. Both PM and AM cuts were field-wilted and harvested as baleage (531 +/- 15.0 g of dry matter/kg of fresh matter). Bales (PM and AM) were ranked according to their concentrations of TNC, paired, and each pair of PM and AM baleages was then assigned to each experimental day (total of 48 d). The difference in TNC concentration between PM and AM baleages fed during the 10 d of data and sample collection varied from -10 to 50 g/kg of dry matter. Each pair of baleage was fed ad libitum to cows once daily with no concentrate. Ruminal molar proportion of acetate and total volatile fatty acid concentration were greater in animals fed the AM baleage, whereas the proportion of valerate was greater with PM baleage; no other significant changes in ruminal molar proportions of volatile fatty acids were observed between forage treatments. Digestible organic matter intake, organic matter digestibility, and plasma Lys concentration were significantly greater in cows fed PM alfalfa, suggesting that more nutrients were available for milk synthesis. Significantly lower body weight gain and retained N as a proportion of N intake were observed in cows fed PM alfalfa, thus suggesting that nutrients were channeled to milk synthesis rather than to body reserves. Intake of dry matter (+1.0 kg/d), and yields of milk (+1.0 kg/d), milk fat (+70 g/d), and milk protein (+40 g/d) were significantly greater in cows fed PM vs. AM alfalfa. Concentration of milk urea N and excretion of urea N as a proportion of total urinary N were significantly reduced, and milk N efficiency was increased when feeding PM vs. AM alfalfa, indicating an improvement in N utilization. Increasing the TNC concentration of alfalfa by shifting forage cutting from sunup to sundown improved N utilization and milk production in late-lactation dairy cows.

Spontaneous fracture of the ceramic ball in a ceramic-polyethylene total hip arthroplasty.

Fractures of the ceramic ball in total hip arthroplasty are an uncommon cause of arthroplasty failure, and reports of this complication in ceramic-on-polyethylene total hip arthroplasty articulations are rare. Ball fractures have been reported in patients who were overweight, had high levels of activity, or had been injured. Other postulated contributory factors have included small ball diameter, defects in ceramic quality or manufacture, and errors in implantation of the arthroplasty. A case of a ceramic ball fracture in a ceramic and polyethylene articulation is reported, and the literature on such fractures is reviewed.

A dominantly inherited progressive disease in a black family characterised by cerebellar and retinal degeneration, external ophthalmoplegia and abnormal mitochondria.

A report is given of a black family with a dominantly inherited, neuro-retinal degeneration associated with abnormally large mitochondria, in which the cristae are disoriented. The disease is characterised by progressive external ophthalmoplegia, clear-cut macular degeneration, cerebellar dysarthria, spastic paraplegia and finally facial and bulbar weakness. A similar illness has been described in black families and individuals and we suggest that the disease may represent a specific syndrome, possibly confined to blacks, that lies within the spectrum of the so-called mitochondrionopathies.

Treatment assessment of learning disabled children: is there a role for frequently repeated neuropsychological testing?

Test/retest practice effects among learning disabled (LD) and non-learning disabled (NLD) children were examined using the Halstead Category Test. Two experimental paradigms were performed. The first compared subjects on successive trials. The second paradigm used a control group to compare second trial performance of the experimental group with first trial performance of the controls. Both paradigms provide evidence of the relative inability of LD children to profit from practice. It is suggested that neuropsychological data can be used for short term test/retest as one indication of the efficacy of treatment intervention for learning disabled children without the practice effect being a significantly confounding variable.

HLA-A,B and DR matching in corneal transplantation.

One hundred eighty-five consecutive corneal transplants were performed in recipients selected on the basis of the best available HLA-A,B and DR match. Endothelial rejection-free transplant survival in this group was compared to a retrospective historical control group of 199 consecutive transplants performed in recipients selected on the basis of age and longest wait criteria. The two groups were comparable with regards to primary diagnosis, preoperative corneal vascularization, donor and recipient age, and operative techniques. Thirty-eight transplants in the study group and 28 transplants in the control group were at high risk for endothelial transplant rejection. At 12 months, the estimated rejection-free survival (Kaplan-Meier method) of the high-risk study group transplants was 87% compared to 74% for the high-risk historical control group and transplants. This difference did not reach the significant level of 0.05 with the log-rank test. The 12-month estimated rejection-free survival of low-risk study group and historical control group transplants were similar. In the study group, the 12-month estimated rejection-free survival of well-matched transplants was 95% compared to 83% for poorly matched transplants (log rank, P less than 0.02). These findings suggest that a relationship exists between HLA-A,B and DR compatibility of donor and recipient and the corneal rejection-free transplant survival.

Corneal ulcers associated with contact lens wear.

We reviewed the experience with ulcerative keratitis associated with contact lens wear at Wills Eye Hospital, Philadelphia, from Jan 1, 1978 through July 1, 1983. Of the 322 cases of ulcerative keratitis, 56 cases (17%) were associated with the use of contact lenses. Twenty-nine (52%) of the 56 cases of contact lens-associated ulcers were culture positive. Pseudomonas was the most common isolate, occurring in 13 (23%) of the 56 cases. Staphylococcus species were the second most common, occurring in 11 (20%) of the 56 cases. In this series, contact lens-associated ulcers were seen frequently in those wearing soft lenses (48/56 cases or 86%) and in those wearing aphakic lenses (32/56 cases or 57%). Contact lens use is an increasingly important risk factor for the development of corneal ulcers. Prompt, appropriate, and intensive treatment is necessary to prevent visual loss.

Treatment of herpes simplex keratitis: comparison of acyclovir and vidarabine.

At three university centres 66 patients presenting with herpetic dendritic or geographic ulcers participated in a double-blind comparative study of 3% acyclovir and 3% vidarabine ointment. There was healing in 31 (97%) of the 32 patients treated with acyclovir, in a mean time of 6.3 days, and in 30 (88%) of the 34 treated with vidarabine, in a mean time of 7.1 days. The two medications were statistically equally effective, no difference being demonstrated in the healing rate, in the frequency of punctate epithelial keratitis or stromal keratitis, or in the final visual acuity.