Corneal sensitivity and aqueous tear production in dogs undergoing evisceration with intraocular prosthesis placement

OBJECTIVE: To determine whether there is an association between evisceration with intraocular prosthesis placement via a dorsal scleral approach and decreased corneal sensitivity or aqueous tear production in dogs. DESIGN: Prospective study. PROCEDURE: Twenty-one dogs scheduled to undergo unilateral evisceration with intraocular prosthesis, and with a normal normotensive contralateral eye, based on slit-lamp biomicroscopy, indirect ophthalmoscopy and applanation tonometry, were included in the study. Central corneal sensitivity was measured with a Cochet-Bonnet esthesiometer prior to (week 0) and 2, 7, 14 and 28 weeks following surgery. Other pre- and postoperative data collected were Schirmer's tear test (STT I), Schirmer's tear test with topical anesthesia (STT II), corneal fluorescein retention, and intraocular pressure (IOP; postoperative control eye only). Axial globe length was determined for both eyes. Scleral incision length in the surgery eye was also recorded. RESULTS: Corneal sensitivity was significantly lower in eyes undergoing evisceration with intraocular prosthesis than in control eyes both preoperatively and postoperatively at all time points. There was no significant difference between preoperative and postoperative corneal sensitivity within the two groups. There was no significant difference in STT I or STT II-values between control eyes and surgery eyes preoperatively. There was a significant difference between preoperative and 2-week postoperative STT I in the surgery eye. There was a significant difference between the preoperative and 28-week postoperative STT II in the surgery eye. The 28-week postoperative STT I-values differed significantly between control and surgery eyes. Corneal sensitivity tended to decrease with increased degree of buphthalmos or with increased scleral incision length, although neither relationship was statistically significant. CONCLUSIONS: Eyes that have sustained chronically elevated intraocular pressure had decreased axial corneal sensitivity compared to normal eyes, which persisted even after intraocular pressure was reduced. The presence of buphthalmos appeared to be a factor in globes developing decreased corneal sensitivity. Evisceration via a dorsal scleral incision did not result in a significant further reduction in axial corneal sensitivity. A mild reduction in aqueous tear production occurred over time in globes following evisceration with intraocular prosthesis.     

Penetrating keratoplasty in a California Brown Pelican

Fresh homologous penetrating keratoplasty (PK) was performed on the left cornea of a young adult female California Brown Pelican (Pelecanus occidentalis) for the treatment of vision-threatening corneal scarring and granulation tissue. The procedure appeared to be highly successful based on short-term clinical follow-up and histopathology results. However, the patient died from unrelated causes before long-term follow-up could be obtained.     

Central corneal thickness in koi fish: effects of age, sex, body length, and corneal diameter

OBJECTIVE: To establish the central corneal thickness (CCT) of normal koi fish by ultrasonic pachymetry, and its relationship to age, sex, body length and corneal diameter. METHODS: Age, sex and body length of 33 koi fish (17 male and 16 female fish) were recorded. Horizontal and vertical corneal diameters of each eye were obtained using Jameson calipers. Central corneal thickness of all eyes was measured by ultrasonic pachymetry. Intraocular pressure (IOP) by rebound tonometry was obtained for a subgroup of nine koi (18 eyes). RESULTS: Mean central corneal thickness was 325.9 microm. Central corneal thickness of female koi was greater than CCT of male fish (P < 0.01). Central corneal thickness increased with increasing age overall and within both sexes (P < 0.01). Central corneal thickness increased with increasing body length (P < 0.001). For male and female fish, CCT increased with increasing horizontal and vertical corneal diameters (P < 0.01). Mean horizontal corneal diameter (HCD) was 8.05 mm, mean vertical corneal diameter (VCD) was 7.38 mm, and HCD was consistently greater than VCD. Mean IOP of a subgroup of these koi was 4.9 mmHg by rebound tonometry. CONCLUSIONS: Koi CCT increases with increasing age, body length and corneal diameter.     

Regulation of interprotein electron transfer by residue 82 of yeast cytochrome c

Yeast iso-1-cytochrome c (Cc) mutants have been constructed with Phe, Tyr, Gly, Ser, Leu, and Ile at position 82, each with Thr substituted for Cys at position 102. Their long-range electron transfer with zinc-substituted cytochrome c peroxidase (ZnCcP) has been studied by two kinetic techniques. The charge-separated complex, [(ZnCcP)+,FeIICc] converts to [ZnCcP,FeIIICc] by a single, intracomplex electron transfer step that is not governed by "gating" through possible rapid dissociation of the complex or isomerization (for example, heme-ligand) by FeIICc subsequent to its formation from FeIIICc. In every variant with an aliphatic residue at position 82 of Cc, the rate of this electron transfer process is approximately 10(4) slower at approximately 0 degrees C than for the two variants with aromatic residues.     

Composition and structure of the venus atmosphere: results from pioneer venus

Results from the Pioneer Venus sounder probe neutral mass spectrometer indicate that there is no difference in the isotopic ratios of carbon and oxygen between Venus and Earth to within +/- 5 percent. The mixing ratio of nitrogen is 3.5(+3)(-2) percent with an isotopic ratio within 20 percent of that of Earth. The ratio of argon-36 to argon-40 is 85 percent, and the ratio of argon-38 to argon-36 is 20 percent. The mixing ratios of argon-36 and argon-40 are approximately 40 and 50 parts per million, respectively, with an error of about a factor of 2 (mainly toward a lesser amount) resulting from uncertainty in the response of the ion pump to rare gases. Hydrogen chloride cannot account for more than a few percent of the 36 mass peak, and therefore the large excess of primordial argon is a reasonable conclusion. The ratio of neon-20 to argon-36 of 0.5 +/- 0.3 is definitely terrestrial in character rather than solar. These results indicate that there is a large excess of all primordial noble gases on Venus relative to Earth. There appears to be a considerably higher abundance of sulfur compounds below 20 kilometers than in or above the main cloud layer. The 32 and 60 mass peaks show a sharp increase below 22 kilometers, indicating the possible production of sulfur and carbon oxysulfide (COS) at the expense of sulfur dioxide.     

The mechanism of diamond nucleation from energetic species

A model for diamond nucleation by energetic species (for example, bias-enhanced nucleation) is proposed. It involves spontaneous bulk nucleation of a diamond embryo cluster in a dense, amorphous carbon hydrogenated matrix; stabilization of the cluster by favorable boundary conditions of nucleation sites and hydrogen termination; and ion bombardment-induced growth through a preferential displacement mechanism. The model is substantiated by density functional tight-binding molecular dynamics simulations and an experimental study of the structure of bias-enhanced and ion beam-nucleated films. The model is also applicable to the nucleation of other materials by energetic species, such as cubic boron nitride.     

Foliar and yield response of Santa rosa plum to saline water spray

Summary Canopies of 22-year-old Santa Rosa plum trees irrigated with mini-sprinklers below the canopy with nonsaline (0.3 dS/m) water were sprayed weekly during one irrigation season with water having six levels of salinity (0.3, 1.1, 2.1, 3.3, 4.5, and 6.8 dS/m) to evaluate the extent of leaf injury, foliar absorption of Cl and Na, and yield response. Recognizable leaf injury was caused by spray water containing 29 mol/m³ of chloride and 15 mol/m³ of sodium. Severe leaf damage occurred when the leaf chloride and sodium concentrations exceeded 300 and 125 mmol/kg (dry weight), respectively. These concentrations were higher than those causing foliar damage on other trees in the same orchard which had been irrigated below the canopy with water having the same salinity as that sprayed on the canopy. No residual foliar injury was observed during the irrigation season following the year when the spray treatments were applied. Fruit yield measured six weeks after treatments were initiated was unaffected. In the following 2 years, yield was reduced by the highest salinity levels, even though the salt spray treatments were not continued and no foliar injury was visible.