Biomedical subjects

A M Willis

Publications and source records attributed to A M Willis.

17 recordsLinked to original sources

PubMed2003

Effects of topical administration of 1% brinzolamide on normal cat eyes.

OBJECTIVE: To evaluate the effect of short-term daily topical administration of 1% brinzolamide on the intraocular pressure (IOP) of healthy domestic cats with normotensive eyes and to assess the potential for negative side effects of drug administration. ANIMALS: Twelve privately owned adult domestic cats without physical or ocular abnormalities. PROCEDURE: Normal variation in IOP was determined on day 1. Cats were then treated on days 2-8 with a topical placebo (artificial tear solution) OU q 12 h. On days 9-15 the cats were treated q 12 h with 1% brinzolamide in one randomly selected eye and the placebo in the contralateral eye. All medications (drug and placebo) were administered twice daily at 7 a.m. and 7 p.m. On days 16-22 the cats received no topical medications. IOP, horizontal pupil size in mm and assessment of conjunctival hyperemia were noted OU on days 1, 8, 15 and 22 at 5 time points (9 a.m., 11 a.m., 1 p.m., 3 p.m. and 5 p.m.). Mixed linear regression models were used to compare the IOP of each eye at all time periods for each cat, controlling for age and weight. RESULTS: Mean IOP was not significantly altered in any eye at any time point during the treatment period compared with pretreatment, baseline, or follow-up evaluations. Conjunctival hyperemia and miosis were not detected in either eye at any time point. Conclusions and clinical relevance Short-term q 12 h administration of 1% brinzolamide did not significantly reduce IOP in this small sample population of normotensive cats under these study conditions. No clinically relevant side effects were noted with brinzolamide administration.

Administration, Topical↗

PubMed2001

Description of ciliary body anatomy and identification of sites for transscleral cyclophotocoagulation in the equine eye.

OBJECTIVE: To determine the most appropriate anatomical location for diode laser probe placement to accurately photoablate the equine ciliary body using a contact, transscleral approach. DESIGN: Original research. PROCEDURES: Forty-two freshly enucleated adult equine eyes were evaluated. The horizontal, medial vertical, central vertical, and lateral vertical lengths of the cornea were measured from limbus to limbus. Needles were inserted perpendicular to the sclera at specific distances posterior to the external limbus at the 1, 2, 4, 5, 6, 7, 8, 10, 11 and 12 o'clock positions. The per cent frequency that needles penetrated internal anatomical regions (lens, lens zonules, pars plicata, anterior, middle, and posterior pars plana, ora ciliaris retinae, or retina), when inserted at 2, 4, 6, and 8 mm posterior to the limbus, were calculated for all eyes combined, for right vs. left, for males vs. females, and for three age groups. The internal distance from the limbus to the anterior pars plana, and from the anterior pars plana to the ora ciliaris retinae were also measured in six of the horses (12 eyes). Mean distances and standard deviations were computed for all parameters. RESULTS: Average corneal sizes and standard deviations were: 30.24 mm +/- 1.53 (horizontal); 24.69 mm +/- 1.52 (central vertical); 22.79 mm +/- 1.49 (medial vertical); and 19.79 mm +/- 1.55 (lateral vertical). Internal distances of the pars plicatas ranged from 5.33 mm +/- 0.49 to 10.67 mm +/- 1.15. Internal distances of the pars planas ranged from 0.33 mm +/- 0.49 to 3.17 mm +/- 0.39. High probabilities of penetrating the pars plicata correspond to positions 4 mm posterior to the external limbus dorsotemporal 10, 11 o'clock (OD), and 1, 2 o'clock (OS), dorsonasal 1 o'clock (OD) and 11 o'clock (OS), and ventrotemporal 5-7 o'clock (OU). Low probabilities of penetrating the pars plicata correspond to positions ventronasal 4 o'clock (OD), 8 o'clock (OS) and dorsonasal 2 o'clock (OD), 10 o'clock (OS) at 4 and 6 mm posterior to the external limbus as well as ventrotemporal 4 o'clock (OS), 8 o'clock (OD) at 6 mm posterior to the external limbus. CONCLUSIONS: Transscleral cyclophotocoagulation may be a viable alternative to medical therapy for control of intraocular pressure in horses with glaucoma. Overall, the most accurate anatomical position on the sclera for cyclophotocoagulation of the equine eye is 4-6 mm posterior to the limbus, avoiding the nasal quadrants. Accurate transscleral cyclophotocoagulation should optimize the therapeutic outcome and minimize potential side-effects such as retinal detachment and cataract formation.

Animals↗

PubMed2001

Ocular oncology.

Neoplasia can affect all ocular tissues. The clinical appearance of ocular neoplasia can vary considerably depending on the specific tissue involved. Intraocular neoplasia may mimic or incite ocular inflammatory disease in addition to causing hyphema or secondary glaucoma. Intraocular neoplasms can be primary tumors or may be secondary to metastatic disease or systemic neoplasia. Primary neoplasms, metastatic tumors, tumors extending from adjacent structures, and systemic neoplasms can also affect the adnexal tissues. Many ophthalmic tumors are histologically benign but are locally invasive and, within the confined space of the eye or orbit, can produce significant tissue distortion. Certain ocular neoplasms, such as many canine eyelid tumors, are amenable to simple excision and can be adequately managed in general practice. The evaluation and treatment of other ophthalmic neoplasms, however, may require the additional equipment available only in larger specialty practices, such as computed tomography and radiation therapy. Early diagnosis of ocular neoplasia is an important aspect of successful management.

Animals↗

PubMed2001

The influence of antifungal drugs on virulence properties of Candida albicans in patients with diabetes mellitus.

OBJECTIVE: This study investigated the influence of nystatin and fluconazole on virulence properties of Candida albicans. STUDY DESIGN: A total of 108 diabetic patients participated in the study. Eighty-eight patients had clinical oral candidosis. Drug therapy was given at 6 hourly intervals for nystatin or daily with fluconazole for a maximum of 2 weeks. Adhesion of C albicans to buccal epithelial cells was determined by using an autologous adhesion assay prospectively over 6 months. Phospholipase production was estimated by using an agar plate method. The data analysis included a paired Student t test and calculation of correlation coefficients. RESULTS: Unlike nystatin, treatment with fluconazole reduced the ability of C albicans to colonize the buccal mucosa for up to 8 weeks after the treatment. Patients without clinical signs of oral candidosis had significantly fewer C albicans isolates producing phospholipase than did patients with oral candidosis. Treatment with fluconazole, but not nystatin, reduced the production of phospholipase from C albicans oral isolates in patients with diabetes mellitus. CONCLUSIONS: In addition to being antifungal, fluconazole alters phospholipase production, modifies buccal epithelial cells, and reduces adhesion of C albicans to human buccal epithelial cells for up to 8 weeks posttreatment in diabetic patients with oral candidosis.

Analysis of Variance↗

PubMed2001

Effects of topical administration of 0.005% latanoprost solution on eyes of clinically normal horses.

OBJECTIVE: To determine the effect of 0.005% latanoprost solution on intraocular pressure (IOP) of eyes of clinically normal horses and establish the frequency of adverse effects of drug administration. ANIMALS: 20 adult clinically normal horses. PROCEDURE: IOP was recorded (7, 9, and 11 AM; 3, 5, and 7 PM) on days 1 and 2 (baseline), days 3 to 7 (treatment), and days 8 to 9 (follow-up). Latanoprost was administered to 1 randomly assigned eye of each horse every 24 hours during the treatment period, following the 7 AM IOP recording. Pupil size and the presence or absence of conjunctival hyperemia, epiphora, blepharospasm, blepharedema, and aqueous flare were recorded prior to IOP measurement. RESULTS: IOP was reduced from baseline by a mean value of 1.03 mm Hg (5%) in males and 3.01 mm Hg (17%) in females during the treatment period. Miosis developed in all treated eyes and was moderate to marked in 77% of horses, with the peak effect observed 4 to 8 hours after drug administration. Conjunctival hyperemia, epiphora, blepharospasm, and blepharedema were present in 100, 57, 42, and 12% of treated eyes, respectively, 2 to 24 hours following drug administration. Aqueous flare was not observed at any time point. CONCLUSIONS AND CLINICAL RELEVANCE: Although IOP was reduced with every 24-hour dosing of latanoprost, the frequency of prostaglandin-induced adverse events was high. Because recurrent uveitis appears to be a risk factor for glaucoma in horses, topical administration of latanoprost may potentiate prostaglandin-mediated inflammatory disease in affected horses.

Administration, Topical↗

PubMed2001

Effect of topical administration of 2% dorzlamide hydrochloride or 2% dorzlamide hydrochloride-0.5% timolol maleate on intraocular pressure in clinically normal horses.

OBJECTIVE: To evaluate the effect of topical administration of 2% dorzolamide hydrochloride or 2% dorzolamide hydrochloride-0.5% timolol maleate on intraocular pressure (IOP) in clinically normal horses. ANIMALS: 18 healthy adult horses without ocular abnormalities. PROCEDURE: The IOP was measured at 5 time points (7 AM, 9 AM, 11 AM, 3 PM, 7 PM) over 11 days. On days 1 and 2, baseline values were established. On days 3 through 5, horses received 2% dorzolamide HCI (group D, n = 9) or 2% dorzolamide HCl-0.5% timolol maleate (group DT, 9) in 1 randomly assigned eye every 24 hours immediately following each daily 7 AM IOP measurement. On days 6 through 9, each drug was given every 12 hours (7 AM and 7 PM) in the treated eye. Measurements on days 10 and 11 assessed return to baseline. Mixed linear regression models compared mean IOP difference for each drug at each time period. RESULTS: Mean IOP decreased significantly in all eyes during the 2 dose/d period, compared with the baseline, 1 dose/d, and follow-up periods. CONCLUSIONS AND CLINICAL RELEVANCE: Administration of either drug every 24 hours for short-term treatment does not reduce IOP significantly. Administering either drug every 12 hours induced a significant reduction of IOP; however, controlling for all variables, the reduction was less than 2 mm Hg.

Administration, Topical↗

PubMed2000

Feline leukemia virus and feline immunodeficiency virus.

Ophthalmic manifestations of FeLV or FIV infection can occur in all ocular tissues and may be manifestations of direct viral effects or secondary to viral-related malignant transformation. Additionally, the manifestations of common feline ophthalmic pathogens may be more severe and poorly responsive to therapy because of the immunosuppressive effects of FeLV or FIV infection. Prompt diagnosis of underlying viral infection in cats with ophthalmic disease is paramount for accurate diagnosis and prognosis and is required for appropriate therapeutic decision making.

Animals↗

PubMed2000

Canine viral infections.

The ophthalmic effects of viral infection are varied. With the added possibility for pathologic effects of attenuated vaccine viruses, the diagnosis of viral diseases can be a challenge. In many cases, ocular manifestations can provide added support to a presumptive diagnosis of viral disease, thereby underscoring the benefit of thorough ophthalmic examination of any animal with nonspecific signs of illness.

Adenoviridae Infections↗

PubMed2000

Isolation of C. dubliniensis from insulin-using diabetes mellitus patients.

The identification of the novel candidal species, C. dubliniensis, from oral swab studies of HIV-seropositive and -seronegative individuals has led to speculation that such a species may also reside in the oral cavity of other patient groups. In this study involvement of the newly described species, C. dubliniensis, was investigated in oral carriage and disease in 414 insulin-using diabetes mellitus patients. Seventy-seven percent of the diabetic patients carried candidal species in the oral cavity. C. albicans was the most commonly identified candidal species. This was followed by C. dubliniensis, which was isolated on 64 occasions. Colonisation with multiple candidal species was common, and C. dubliniensis was present in both carriage and disease states. Seven patients without signs of oral disease had C. dubliniensis isolated as the sole candidal species, while the same species was associated with various forms of oral candidosis in six patients.

Candida↗

PubMed2000

Factors affecting the adhesion of Candida albicans to epithelial cells of insulin-using diabetes mellitus patients.

This study investigated the influence of the carbon source of the growth medium, strains of Candida albicans and source of epithelial cells, and the influence of smoking and gender, on the adhesion of C. albicans to epithelial cells from insulin-using diabetic patients. Adhesion was determined by an autologous adhesion assay with exfoliated buccal or palatal epithelial cells and one strain of C. albicans isolated from each patient. The type strain CBS 562 was also used. Glucose or sucrose were used as the predominant carbon sources of the growth medium. The autologous strain of C. albicans adhered selectively to the oral mucosa of diabetic patients. Palatal epithelial cells retained significantly more C. albicans in vivo and adhesion was influenced by the availability of sugars in the growth medium and the strain of C. albicans.

Candida albicans↗

PubMed2000

Melting corneal ulcer management in a greater one-horned rhinoceros (Rhinoceros unicornis).

Acute unilateral keratomalacia, probably secondary to trauma, occurred in a greater one-horned rhinoceros (Rhinoceros unicornis) transferred between zoologic facilities. Following 2 days of medical treatment, a 360 degrees conjunctival surgical graft was performed. Staphylococcus and yeast were isolated from a perioperative culture of the affected eye and were treated with antimicrobials. There was rapid healing and minimal midcorneal scar formation with peripheral corneal clarity.

Animals↗

PubMed2000

Evaluation of intraocular pressure in eyes of clinically normal llamas and alpacas.

OBJECTIVE: To estimate intraocular pressure (IOP) in eyes of healthy camelids, using applanation tonometry. ANIMALS: The eyes of 34 camelids (16 llamas [Lama glamal and 18 alpacas [L. pacos]) that did not have major abnormalities of the ocular surface or intraocular abnormalities. PROCEDURE: Tonometry measurements were obtained from each eye 3 times during a 24-hour period. Each measurement was the mean of several corneal applanations obtained by use of an applanation tonometer. Data were analyzed, using an ANOVA for a repeated-measures design. RESULTS: Mean (+/- SEM) IOP of llamas and alpacas was 13.10+/-0.35 and 14.85+/-0.45 mm Hg, respectively. Range of IOP was 7 to 18 mm Hg for llamas and 11 to 21 mm Hg for alpacas. Mean IOP of llamas was significantly less than the mean IOP of alpacas. Significant differences in IOP were not detected between the right and left eye of animals. Significant differences in IOP were not attributed to sex, age, or time of measurement within llamas or alpacas. CONCLUSIONS AND CLINICAL RELEVANCE: Establishing the mean and range of IOP of clinically normal llamas and alpacas provides a frame of reference that is important for use in a complete ophthalmic examination of camelids, which can assist clinicians in the diagnosis of glaucoma and uveitis. Reasons for the difference in mean IOP between llamas and alpacas are unknown. Although the difference may be unimportant clinically, this finding reiterates the fact that caution must be used when extrapolating IOP among species.

Animals↗

PubMed1999

Sino-orbital aspergillosis in a dog.

Fungal rhinitis-sinusitis with orbital involvement was diagnosed in a dog with profuse unilateral ocular and bilateral nasal discharge, enophthalmos, and a corneal descemetocele. The descemetocele was treated with a conjunctival pedicle graft. Frontal sinusotomy was performed, and clotrimazole was infused through catheters placed in the frontal sinuses and nasal cavities to saturate the tissues for 1 hour. Successful resolution of orbital infection may have been aided by a fistula between the frontal sinus and orbit that allowed delivery of clotrimazole to the orbit. The dog retained sight in the affected eye, and clinical signs of infection were not detected 14 months later, although enophthalmos and medial strabismus may have been caused by persistent postinflammatory fibrosis.

Animals↗

PubMed1999

Brow suspension for treatment of ptosis and entropion in dogs with redundant facial skin folds.

Brow suspension surgery was performed on 7 dogs with redundant facial skin folds, associated ptosis, and entropion. The surgical technique involved subcutaneous placement of polyester mesh strips to suspend the upper eyelid from the dorsal frontalis muscle and the underlying periosteum of the skull. Visual impairment associated with ptosis was resolved in all dogs at the 2 week reevaluation period. Upper eyelid position was maintained in 4 of 7 dogs available for long-term follow-up. One dog developed persistent draining tracts in the region of the implant, and removal of part of the implanted mesh was eventually required. Upper eyelid height in this dog, however, was maintained following mesh removal, probably because of fibrosis around the implant. Brow suspension is an option for surgical management of upper eyelid ptosis and entropion in dogs with redundant skin folds and avoids the need for facial skin fold excision.

Animals↗

PubMed1999

Oral candidal carriage and infection in insulin-treated diabetic patients.

AIM: To evaluate candidal load and carriage of candidal species in 414 insulin-treated diabetes mellitus patients with and without clinical signs of infection. Host factors that could influence candidal load in diabetic patients with oral candidosis were also investigated. METHODS: Candidal species were recovered from 414 insulin-treated diabetes mellitus patients attending two hospital diabetic clinics, using an oral rinse technique. RESULTS: Seventy-seven per cent of diabetic patients carried Candida species in their oral cavity, with C. albicans being the species most frequently isolated. C. dubliniensis was found for the first time in this patient group. Forty per cent of patients colonized with candidal species had no clinical signs of oral candidosis. Where oral candidosis was present, erythematous candidosis was the most common clinical presentation. Candidal load was not associated with age, sex or glycaemic control. However, it was significantly increased in those patients who were tobacco smokers, and non-significantly increased in those patients who wore dentures, or who had clinical signs of oral candidosis. CONCLUSION: The epidemiology of oral candidal carriage and infections in diabetic patients is complex and includes species which have not been previously reported in this group of patients. The development of oral candidosis in insulin-treated diabetes mellitus patients is not the result of a single entity, but rather, a combination of risk factors.

Analysis of Variance↗

PubMed1996

Hypertension and renal disease.

Systemic hypertension is commonly associated with chronic renal failure in dogs and cats. Consequences of systemic hypertension are manifested by pathologic changes involving the eyes, heart, central nervous system, and/or kidneys. These changes may be prevented or reversed by diagnosing and treating systemic hypertension. Therefore, blood pressure determination and ophthalmic examination should be performed routinely in animals with chronic renal failure. Therapy for systemic hypertension associated with chronic renal failure should be initiated cautiously with the goal being to lower arterial pressure below values considered to be hypertensive. Therapy may involve nonpharmacologic strategies and/or hypertensive drugs. This article discusses pathophysiologic mechanisms, consequences, diagnosis, and treatment of systemic hypertension associated with chronic renal failure in dogs and cats.

Animals↗

PubMedDate not supplied

Transarterial coil embolization of the internal and external carotid and maxillary arteries for prevention of hemorrhage from guttural pouch mycosis in horses.

OBJECTIVES: To develop a transarterial coil embolization technique for occlusion of the internal carotid artery (ICA), external carotid artery (ECA), and maxillary arteries (MA) in normal horses and to evaluate this technique for prevention of hemorrhage in horses affected with guttural pouch mycosis. ANIMALS: Ten adult, normal horses and 4 horses with guttural pouch mycosis. METHODS: All horses had transarterial coil embolization of the rostral and caudal ICA, caudal MA, and rostral ECA. In 1 affected horse, an aberrant actively bleeding branch of the ECA was also occluded. Normal horses had a premortem angiogram, and were killed either at 1 or 2 weeks or 1, 2, or 3 months after the procedure. Specimens from the ICA, ECA and MA were evaluated by light microscopy. RESULTS: No surgical complications were observed, except 1 horse that developed laryngeal hemiplegia and 1 pilot horse that had embolization of the cerebral arterial circle. In normal horses, premortem angiography confirmed complete occlusion of all vessels, and coils were positioned as intended. All normal horses had partially maturing to mature, continuous thrombi occluding at the coils. In affected horses, no further episodes of epistaxis were observed. By day 60, all mycotic plaques had resolved without further treatment. Ophthalmic complications were not observed. CONCLUSION: Transarterial embolization provided a safe, rapid, and effective method for ICA, ECA, and MA occlusion in normal and affected horses. In affected horses, the technique was possible despite active bleeding, allowing adequate identification and occlusion of all sources of hemorrhage.

Angiography↗