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To describe and evaluate the use of corneoconjunctival transposition as a surgical treatment for corneal sequestra in cats.Fifteen cats (17 eyes) of various breeds and ages with corneal sequestra treated surgically with corneoconjunctival transposition.Retrospective medical records study.Median age was 39 months. Eight patients were castrated males, five were spayed females, and two were intact females. The left eye was affected in eight cats, the right eye was affected in five cats, and both eyes were affected in two cats. Mean (+/- SD) sequestrum diameter was 4.4 +/- 2.4 mm (range 1-10 mm) and the sequestrum was located centrally in all cases. Sequestra occurred in the superficial stroma in 8/17 corneas, in the anterior one third of the stroma in 3/17 corneas, and in the middle one third of the stroma in 6/17 corneas. Median duration of clinical signs prior to presentation was 39 days (range 14-1095 days). Median time to healing, defined as the number of days from surgery to cessation of medical treatment, was 34 days (range 25-86 days). There were no recurrences and minimal scar formation.Corneoconjunctival transposition is a valid procedure for surgical treatment of corneal sequestra in cats. The procedure results in excellent cosmesis and functional vision with no recurrences.

The objective of this study was to evaluate the possible relationship between the administration of parenteral and/or oral [corrected] enrofloxacin and the onset of acute retinal degeneration in cats. The animals studied included 17 cats that received systemic enrofloxacin and developed retinal degeneration soon thereafter.In this retrospective clinical study, cats that received parenteral and/or oral [corrected] enrofloxacin and developed acute blindness were identified. Parameters recorded included breed, age, sex, enrofloxacin dosage (daily dose and number of days administered), medical condition for which the antibiotic had been prescribed, ophthalmic signs, examination results, and the visual outcome. Fundus photographs were obtained in seven cats, and electroretinography was performed in five cats. Histopathology was performed on two eyes from one cat (case 1) that received enrofloxacin 5 months previously and developed retinal degeneration.All cats were the domestic shorthair breed; seven were females (one neutered) and ten were males (seven castrated). Ages ranged from 3 to 16 years old (mean +/- SD; 8.8 +/- 4.6 years). The medical disorders for which enrofloxacin was administered ranged from lymphoma and pancreatitis to otitis and dermatitis, and eight cats had urinary diseases. The daily and total dosage of enrofloxacin and number of days of administration were also highly variable. Presenting clinical signs were most often mydriasis and acute blindness. All cats had diffuse retinal degeneration as evidenced by increased tapetal reflectivity and retinal vascular attenuation. Absence of recordable electroretinographic responses suggested diffuse and extensive outer retinal disease. Vision returned in a few cats, but the retinal degeneration persisted or even progressed. Histopathology of two eyes revealed primarily outer retinal degeneration, with diffuse loss of the outer nuclear and photoreceptor layers, and hypertrophy and proliferation of the retinal pigment epithelium.Parenteral and/or oral [corrected] enrofloxacin is potentially retinotoxic in some cats, and may result in acute and diffuse retinal degeneration. Blindness often results, but some cats may regain vision. Practitioners should adhere closely to the manufacturer's current enrofloxacin dosage recommendation (5 mg/kg q 24 h), and continue clinical observations for this drug toxicity in cats.

The viscosity of whole blood measured at low shear rates is determined partly by shear resistance of the red cell aggregates present, stronger aggregation increasing the viscosity in the absence of other changes. Effects of cell deformability can confound interpretation and comparison in terms of aggregation, however, particularly when the plasma viscosity is high. We illustrate the problem with a comparison of hematocrit-adjusted blood from type 1 diabetes patients and controls in which it is found the apparent and relative viscosities at a true shear rate of 0.20 s-1 are lower in the patient samples than age matched controls, in spite of reports that aggregation is increased in such populations. Because the plasma viscosities of the patients were higher on average than controls, we performed a series of experiments to examine the effect of plasma protein concentration and viscosity on normal blood viscosity. Dilution or concentration by ultrafiltration of autologous plasma and viscosity measurements at low shear on constant hematocrit red cell suspensions showed (a) suspension viscosity at 0.25 and 3 s-1 increased monotonically with plasma protein concentration and viscosity but (b) the relative viscosity increased, in concert with the microscopic aggregation grade, up to a viscosity of approximately 1.25 mPa-s but above this the value the relative viscosity no longer increased as the degree of aggregation increased in concentrated plasmas. It is suggested that in order to reduce cell deformation effects in hyperviscous pathological plasmas, patient and control plasmas should be systematically diluted before hematocrit is adjusted and rheological measurements are made. True shear rates should be calculated. Comparison of relative viscosities at low true shear rates appears to allow the effects of red cell aggregation to be distinguished by variable shear rate viscometry in clinical blood samples.

To investigate the distribution of intraocular pressure (IOP) and cup properties in a colony of rhesus monkeys that has had no outside genetic input since 1938 (approximately 12 generations). This sample of sequestered monkeys is significantly larger than any previously reported. Comparisons are made with a sample of random-source monkeys to develop population estimates defining the limits of normalcy.The IOP and cup/disc ratio estimates were collected from 701 eyes of 354 adult rhesus monkeys from the closed colony on Cayo Santiago, Puerto Rico. Results for IOP were compared with the normal rhesus IOP population distribution function calculated from an earlier sample of genetically heterogeneous rhesus.The mean +/- standard deviation IOP in the Cayo Santiago monkeys (15.8+/-3 mmHg) related well to the calculated "normal" rhesus distribution (14.5+/-2 mmHg) below and around the mean IOP only. Above the mean rhesus IOP, the samples from the Cayo monkeys were strongly skewed: 129 eyes had IOP more than two standard deviations above the normal mean IOP, and 54 eyes had IOP more than three standard deviations above the normal mean IOP. Cup/disc ratio estimations tended to cluster as higher values in the higher IOP quartiles. Some eyes with IOP below the mean had cup/disc ratios0.5. Values for IOP that were more than two standard deviations above the mean and cup/disc ratios0.4 were not uniformly distributed across social groupings, although incidence of high IOP was more than 25% in one group.After 12 generations with the same genetic pool, expression of ocular hypertension and large optic disc cups is high but not uniform.

The authors identify any diurnal intraocular pressure (IOP) variation in healthy Cayo Santiago macaques, as well as Cayo Santiago macaques with normotensive and hypertensive primary open-angle glaucoma (POAG), to further evaluate their potential value as a model for human POAG.Twenty-four monkeys (eight animals each of the healthy control, normotensive glaucoma, and hypertensive glaucoma groups) were sedated with ketamine hydrochloride and the IOP measured hourly from 8:00 AM until 3:00 PM with a Tonopen XL applanation tonometer (Mentor, Norwell, MA, U.S.A.). Mean IOP time profiles, mean IOPs at each observation time, and linear trends in mean IOP over time were compared among groups. Intraocular pressure rate-of-change over time and residual variation about the regression line for each individual eye were analyzed. Cup/disc ratio (C/D) was compared with baseline IOP, IOP profile mean and slope, and IOP residual variation.A significant group and time effect on mean IOP (p = 0.0001 and 0.011, respectively), with highest values at 2:00 PM or 3:00 PM, and a significant increasing linear trend in mean IOP over time in the hypertensive group were observed (p = 0.012). Intermediate readings between control and hypertensive mean IOPs were identified for the normotensive glaucoma group. The biggest range of IOP variation was found in the hypertensive glaucoma monkeys. Higher variations in IOP did not lead to an increase in C/D.This study provides evidence that the Cayo Santiago macaques are a valuable model for human normotensive and hypertensive POAG.

Size-dependent exclusion of macromolecules from gel matrices has long been discussed in terms of pore models. An alternate approach is to calculate the partition coefficient of the distributed species between the matrix material and the mobile phase assuming that the gel can be treated as a polymer solution of appropriate concentration and molecular weight. This approach is particularly appealing in attempting to predict the behaviour of 'tentacle' phases in which the matrix contains anchored linear neutral polymers. The mean field theory of polymer solution is used to predict K, the partition coefficient of a polymer molecule distributing between the gel and mobile phases. The reduction in entropy suffered by the macromolecule in the gel phase is sufficient to produce an exponential dependence of K on the molecular weight of the partitioning species. The enthalpy of interaction between the gel polymer and the distributed species provides a parameter which describes the specificity or recognition in the interaction. The predicted linear dependence of in K on protein molecular weight is satisfactorily borne out by a data set on eight standard proteins chromatographed on four separate gel types.

Cell partitioning in two-phase aqueous polymer systems was used to examine hydrophobic and surface charge-related membrane properties of fresh and cryopreserved human blood phagocytes. This technique is highly sensitive to cell surface characteristics, and the partition behavior depends exponentially on the membrane properties involved. The transition from fresh to cryopreserved and reconstituted cells was accompanied by a significant loss of net negative charge without detectable alteration in hydrophobic membrane properties as detected by the partition technique. The partition coefficient (PC), which is the proportion of cells partitioning into the upper phase, when measured for fresh cells mixed with dimethyl sulfoxide (Me2SO) and cryopreserved leukocytes. No difference was detected between the PCs of the total leukocytes and phagocytes as determined by differential leukocyte counts of the upper polymer phase. The significantly reduced PC of cells prepared by dextran (Dx) separation in both charge-sensitive and -insensitive systems is attributable to the capacity of Dx to adsorb, in part irreversibly, to cells so that those carrying Dx tend to partition with Dx in the lower phase. These results serve to illustrate the utility of partitioning as a highly sensitive method to probe leukocyte surface membrane properties.

Eight units of blood were drawn into modified CPD containing 25 per cent higher glucose and 17.3 mg adenine (0.25 mM in blood). Red blood cell concentrates (RCC) were prepared to a mean hematocrit (Hct) of 70, the cells stored at 4 C, and plasma adenine and red blood cell adenosine triphosphate (ATP) were measured weekly for 42 days. The removal of plasma in the preparation of RCC reduced by 39 per cent the available adenine. As a result measurable plasma adenine was depleted by 21 days. The loss of ATP in RCC occurs at a significantly faster rate than in whole blood stored under the same conditions. When red blood cells are stored at higher HCT or for periods longer than 35 days, increased anticoagulant adenine levels are recommended.

Two acidic secretory epididymal glycoproteins, protein D of 27,000 daltons and protein E of 28,000 daltons, have been purified and antisera prepared against each separately. Both proteins were found to share common immunological determinants when tested by double immunodiffusion and tandem crossed immunoelectrophoresis. By selective immunoprecipitation, protein D was shown to be synthesized and secreted by all regions of the epididymis with the exception of the initial segments. In contrast, the synthesis and secretion of protein E was restricted to the corpus and proximal cauda.

The fate of adenine in CPD whole blood (17.3 mg/500 ml, or 0.25 mM) was evaluated during 42 days of 4 C storage. In whole blood, 95 per cent of the adenine was removed from the plasma by 42 days while the cellular adenosine triphosphate (ATP) levels remained above 60 per cent of the initial concentration. Packed red blood cells (concentrates) were stored with the same relative quantity of adenine (0.1 mg/ml red blood cells) used in whole blood units by the addition of adenine after packing and were shown to take up adenine in a similar manner. Calculations of the initial adenine distribution indicated higher intracellular adenine concentrations than predicted from distribution equilibrium based on volume considerations. The presence of inorganic phosphate has marginal effects on adenine incorporation but does elevate ATP levels, while contributing to the reduction of 2,3-diphosphoglycerate (2,3-DPG) content. The free adenine equilibrium between plasma and red blood cells favors the red blood cells, suggesting adenine binding by red blood cell membranes as shown by initial distribution studies with 14C-adenine and equilibrium dialysis.

The effects of the administration of methemoglobin (MetHb) prepared in vitro were evaluated in Sprague-Dawley rats given increasing doses of potassium cyanide (KCN). Median lethal dose (LD50) studies were conducted by giving intraperitoneal injections of KCN (in 0.3- to 0.5-ml volumes), then 2 min later administering intravenous (iv) doses of 1000, 1500, or 2500 mg/kg of MetHb through the tail vein. Control rats received an equivalent volume of saline. The resulting LD50 values for KCN were 7.4 +/- 1.1, 11.7 +/- 1.1, 13.9 +/- 1.0, and 14.2 +/- 1.0 mg/kg (mean +/- SD) for the control (no MetHb) and 1000-, 1500-, and 2500-mg/kg dose groups, respectively. Additional groups of rats were given 1000, 1500, or 2500 mg/kg MetHb and submitted for necropsy. The gross finding of darkened kidneys was present in both dose groups, but became consistent and more prominent in the 2500-mg/kg dose group. Evidence of pathologic changes was not present in other organs. Single-dose pharmacokinetic studies were conducted using iv doses of 1600 and 2500 mg/kg MetHb. The elimination half-life was similar in both doses (62.6 min), but the volume of distribution (95.3 +/- 7.2 and 126.3 +/- 5.2 ml/kg, mean +/- SE) and clearance (1.1 +/- 0.1 and 1.5 +/- 0.1 ml/min/kg) were significantly different (P less than 0.05) for the 1600- and 2500-mg/kg dose groups, respectively. From these data we conclude that although MetHb is cleared from the vascular system rapidly, it may be an effective and nontoxic antidote for doses of cyanide up to twice that of the control LD50.