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Biomedical subjects

P E Miller

Publications and source records attributed to P E Miller.

At least 19 recordsLinked to original sources
PubMed2001

Intraocular pressure measurements obtained as part of a comprehensive geriatric health examination from cats seven years of age or older.

OBJECTIVE: To determine intraocular pressure (IOP) in cats > or = 7 years of age undergoing a routine comprehensive geriatric health examination. DESIGN: Prospective study. ANIMALS: 538 cats (1,068 eyes). PROCEDURE: IOP was measured by applanation tonometry following instillation of 0.5% proparacaine. RESULTS: Mean +/- SD IOP for all eyes was 12.3 +/- 4.0 mm Hg (range, 4 to 31 mm Hg). Mean age was 12.3 +/- 2.9 years. Intraocular pressure did not vary significantly cross-sectionally with age. However, in 78 cats, IOP was measured more than once, and follow-up measurements were significantly less than initial measurements (mean time between measurements, 9.4 +/- 3.0 months). The most useful tonometric criteria for identifying ocular abnormalities on the basis of IOP was an IOP > or = 25 mm Hg (mean + 3 SD) or a difference in IOP between eyes > or = 12 mm Hg. Eight cats met these criteria, and 5 of these cats had ophthalmic abnormalities. Low IOP was a nonspecific indicator of the presence of ocular abnormalities, as 111 cats had an IOP < or = 8 mm Hg, but only 2 had uveitis. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that IOP measurements can be a useful addition to a comprehensive geriatric health examination in cats > or = 7 years of age, especially when combined with an ophthalmic examination. Cats without ocular abnormalities that have lOP > or = 25 mm Hg or a > or = 12 mm Hg difference in IOP between eyes should have tonometry repeated or be referred to an ophthalmologist for further evaluation before beginning antiglaucoma treatment.

Aging↗
PubMed2001

Development of glaucoma after phacoemulsification for removal of cataracts in dogs: 22 cases (1987-1997).

OBJECTIVE: To determine factors contributing to glaucoma after lens extraction via phacoemulsification in dogs. DESIGN: Retrospective study. ANIMALS: 22 dogs (29 eyes) with glaucoma and 21 dogs (30 eyes) without glaucoma after phacoemulsification. PROCEDURE: Medical record review. RESULTS: Eyes at increased risk for glaucoma included those of Boston Terriers, those with uveal or retinal abnormalities before surgery, and those with intraoperative intraocular hemorrhage. Significant differences between groups were not detected for incidence of preoperative lens-induced uveitis, presence of an intraocular lens, or frequency of an acute postoperative increase in intraocular pressure. Glaucoma developed (mean +/- SD) 12.8+/-14.1 months (median, 10 months; range, 0.25 to 55 months) after surgery. Eighteen of 29 (62%) eyes with potential for vision after onset of glaucoma retained vision for a mean of 16.5+/-12.8 months (median, 10.8 months; range, 1.5 to 37 months) after glaucoma was diagnosed. Most of these eyes still had vision at the conclusion of the study period. CONCLUSIONS AND CLINICAL RELEVANCE: Risk factors identified by this study will aid in preoperative counseling of clients and refining selection criteria for candidates for phacoemulsification. Careful follow-up for the remainder of the dog's life after surgery may improve long-term success rates by permitting early intervention before intraocular pressure increases substantially and vision is irreversibly lost. Surgery for cataracts may still be worthwhile in dogs with increased risk of glaucoma, especially if elderly, because of the lengthy period to onset of glaucoma after surgery and the beneficial effects of treatment after glaucoma develops.

Animals↗
PubMed2000

Ophthalmomyiasis interna anterior associated with Cuterebra spp in a cat.

An 8-year-old domestic shorthair cat was examined for severe anterior uveitis of the right eye that was unresponsive to aggressive treatment with anti-inflammatory drugs and for a possible intraocular parasite or foreign body trapped within a large fibrin clot in the anterior chamber. Surgical exploration of a presumed entry site on the caudal aspect of the third eyelid led to keratotomy and removal of a larval parasite later identified as a first instar Cuterebra spp. Aggressive treatment with anti-inflammatory drugs was continued after surgery, and intraocular pressure was monitored closely to ensure that the cat did not develop glaucoma. Two weeks after surgery, the cat had vision in the affected eye, with resolving uveitis and a normal fundus. Six weeks after surgery, the uveitis continued to resolve; however, the cat did not have vision in the affected eye, and examination of the fundus revealed retinal atrophy. In contrast to the condition in humans, a Cuterebra spp larval infection within the eye of cats may cause not only an intense, acute inflammatory reaction, but also retinal degeneration and blindness despite prompt surgical removal.

Animals↗
PubMed2000

Mortality of sea lions along the central California coast linked to a toxic diatom bloom.

Over 400 California sea lions (Zalophus californianus) died and many others displayed signs of neurological dysfunction along the central California coast during May and June 1998. A bloom of Pseudo-nitzschia australis (diatom) was observed in the Monterey Bay region during the same period. This bloom was associated with production of domoic acid (DA), a neurotoxin that was also detected in planktivorous fish, including the northern anchovy (Engraulis mordax), and in sea lion body fluids. These and other concurrent observations demonstrate the trophic transfer of DA resulting in marine mammal mortality. In contrast to fish, blue mussels (Mytilus edulus) collected during the DA outbreak contained no DA or only trace amounts. Such findings reveal that monitoring of mussel toxicity alone does not necessarily provide adequate warning of DA entering the food web at levels sufficient to harm marine wildlife and perhaps humans.

Animals↗
PubMed2000

Natural history of arteriovenous grafts in hemodialysis patients.

Most hemodialysis patients in the United States have an arteriovenous graft as their vascular access. Grafts have a relatively short life span and are prone to recurrent stenosis and thrombosis, requiring multiple salvage procedures to maintain their patency. There is little information in the literature regarding the clinical factors that determine graft survival and complications. We evaluated prospectively the outcomes of 256 grafts placed at a single institution during a 2-year period. A salvage procedure to maintain graft patency (thrombectomy, angioplasty, or surgical revision) was required in 29% of the grafts at 3 months, 52% at 6 months, 77% at 12 months, and 96% at 24 months. Thus, primary graft survival (time from graft placement to the first intervention) was only 23% at 1 year and 4% at 2 years. Primary graft survival was significantly less among patients with hypoalbuminemia compared with patients with a normal serum albumin level (P = 0.003). Secondary graft survival (time from graft placement to permanent graft failure) was 65% at 1 year and 51% at 2 years. Neither primary nor secondary graft survival was significantly correlated with patient age, sex, diabetic status, body mass index, or graft site. A mean of 1.22 interventions per graft-year were required to maintain access patency, including 0.51 thrombectomies, 0.54 angioplasties, and 0.17 surgical revisions. In conclusion, hypoalbuminemia is a strong predictor of the requirement for an early graft intervention. Patients with hypoalbuminemia may require a heightened index of suspicion in monitoring their grafts for evidence of stenosis.

Aged↗
PubMed2000

Hamilton county physicians' experience with managed care.

BACKGROUND: Widespread physician participation in managed care over the last several years prompted this survey of the members of the Medical Society of Chattanooga and Hamilton County. METHODS: A 36-item questionnaire was mailed to all members of the Medical Society. RESULTS: Ninety-six responses from solo practitioners and groups representing 325 physicians were analyzed. More than 80% of respondents believed that managed care has affected the quality of patient care negatively and 71.8% believed managed care policies have compromised their patient care. More importantly, 90% said insurers have not secured their input in policy development. Referral processes were regarded as cumbersome or impossible by 78.2%. Regression analysis showed a significant relation between issues of too much managed care control, cumbersome referral processes, and physicians' opinion on impact of managed care on quality of patient care. CONCLUSIONS: Physician dissatisfaction with managed care in Hamilton County appears widespread and is mainly related to issues of too much managed care control over daily patient care, which physicians feel results in compromised quality of patient care.

Adult↗
PubMed1999

Usefulness of aerobic microbial culture and cytologic evaluation of corneal specimens in the diagnosis of infectious ulcerative keratitis in animals.

OBJECTIVE: To determine the diagnostic value of aerobic microbial culture and cytologic evaluation of corneal specimens in the diagnosis of infectious ulcerative keratitis (IUK). DESIGN: Prospective study. ANIMALS: 48 animals (26 dogs, 13 horses, 7 cats, 1 bird, and 1 llama) with corneal ulcers. PROCEDURE: Scrapings from corneal ulcers were examined cytologically. Corneal swab specimens were submitted for microbial culture. Animals were grouped according to whether they had been receiving antimicrobials at the time of admission. RESULTS: Of the 38 animals receiving antimicrobials, 19 had positive results for IUK on cytologic evaluation, 20 on microbial culture, and 26 on cytologic evaluation, microbial culture, or both. Of the 10 animals not receiving antimicrobials at the time of admission, 7 had positive results for IUK on cytologic evaluation, and 9 had positive results on microbial culture. In this group of 10 animals, additional animals with IUK were not identified on the basis of cytologic evaluation alone. When all 48 animals were considered irrespective of antimicrobial treatment, 26 and 29 had positive results for IUK on cytologic evaluation and microbial culture, respectively, whereas IUK was confirmed in 35 animals on the basis of cytologic evaluation, microbial culture results, or both. CONCLUSIONS AND CLINICAL RELEVANCE: Microbial culture and cytologic evaluation of corneal specimens maximizes identification of IUK, especially in animals receiving antimicrobial treatment. Because of serious consequences of untreated IUK, we recommend that both diagnostic tests be used to tailor treatment and reduce risk of vision impairment in animals.

Animal Diseases↗
PubMed1999

Combined cycloablation and gonioimplantation for treatment of glaucoma in dogs: 18 cases (1992-1998).

OBJECTIVE: To evaluate a combined cycloablative and gonioimplantation technique for treatment of glaucoma in dogs. DESIGN: Retrospective study. ANIMALS: 18 adult dogs with glaucoma. PROCEDURE: Medical records of dogs that received a valved gonioimplant and a cyclodestructive procedure (cyclocryoablation or diode laser cyclophotocoagulation) during a 6-year period were reviewed. Retention of vision and intraocular pressure control were assessed, as well as number and nature of complications. RESULTS: 19 eyes of 18 dogs received a valved gonioimplant and either cyclocryoablation (n = 12) or diode laser cyclophotocoagulation (7). At > or = 1 year after surgery, 11 of 19 eyes had vision and 14 of 19 eyes had intraocular pressure < 25 mm Hg. Two dogs (2 eyes) were lost to follow-up 3 and 6 months after surgery. Despite the alternative route for aqueous humor flow created by the gonioimplant, 7 eyes had increased intraocular pressure (27 to 61 mm Hg) < 24 hours after surgery. Other complications included excessive intraocular fibrin, focal retinal detachment, corneal ulcer, retinal hemorrhage, cataract, and implant migration. CONCLUSIONS AND CLINICAL RELEVANCE: Combined cycloablation and gonioimplantation appears to be a promising technique for retention of vision and control of intraocular pressure in dogs with glaucoma.

Animals↗
PubMed1999

Detection of domoic acid in northern anchovies and California sea lions associated with an unusual mortality event.

The occurrence of an unusual mortality event involving California sea lions (Zalophus californianus) along the central California coast in May 1998 was recently reported. The potent neurotoxin domoic acid (DA), produced naturally by the diatom Pseudo-nitzschia australis and transmitted to the sea lions via planktivorous northern anchovies (Engraulis mordax), was identified as the probable causative agent. Details of DA analyses for anchovy tissues and sea lion feces are described. Domoic acid levels were estimated in anchovy samples by HPLC-UV, and in sea lion feces using the same method as well as a microplate receptor binding assay, with absolute confirmation by tandem mass spectrometry. The highest DA concentrations in anchovies occurred in the viscera (223 +/- 5 microg DA g(-1)), exceeding values in the body tissues by seven-fold and suggesting minimal bioaccumulation of DA in anchovy tissue. HPLC values for DA in sea lion fecal material (ranging from 152 to 136.5 microg DA g(-1)) required correction for interference from an unidentified compound. Inter-laboratory comparisons of HPLC data showed close quantitative agreement. Fecal DA activity determined using the receptor binding assay corresponded with HPLC values to within a factor of two. Finally, our detection of P. australis frustules, via scanning electron microscopy, in both anchovy viscera and fecal material from sea lions exhibiting seizures provides corroborating evidence that this toxic algal species was involved in this unusual sea lion mortality event.

Animals↗
PubMed1999

Predictors of adequacy of arteriovenous fistulas in hemodialysis patients.

BACKGROUND: Dialysis access procedures and complications represent a major cause of morbidity, hospitalization, and cost for chronic dialysis patients. To improve the outcomes of hemodialysis access procedures, recent clinical guidelines have encouraged attempts to place an arteriovenous (A-V) fistula, rather than an A-V graft, whenever possible in hemodialysis patients. There is little information, however, about the success rate of following such an aggressive strategy in the prevalent dialysis population. METHODS: We evaluated the adequacy of all A-V fistulas placed in University of Alabama at Birmingham dialysis patients during a two-year period. A fistula was considered adequate if it supported a blood flow of >/=350 ml/min on at least six dialysis sessions in one month. Fistula adequacy was correlated with clinical and demographic factors. RESULTS: The adequacy could be determined for 101 fistulas; only 47 fistulas (46.5%) developed sufficiently to be used for dialysis. The adequacy rate was lower in older (age >/= 65) versus younger (age < 65) patients (30.0 vs. 53.5%, P = 0.03). It was also marginally lower in diabetics versus nondiabetics (35.0 vs. 54.1%, P = 0.061) and in overweight (BMI >/= 27 kg/m2) versus nonoverweight patients (34.5 vs. 55.2%, P = 0.07). The adequacy rate was not affected by patient race, smoking status, surgeon, serum albumin, or serum parathyroid hormone. The adequacy rate was substantially lower for forearm versus upper arm fistulas (34.0 vs. 58.9%, P = 0.012). The adequacy of forearm fistulas was particularly poor in women (7%), patients age 65 or older (12%), and diabetics (21%). In contrast, upper arm fistulas were adequate in 56% of women, 54% of older patients, and 48% of diabetics. CONCLUSIONS: An aggressive approach to the placement of fistulas in dialysis patients results in a less than 50% early adequacy rate, which is considerably lower than that reported in the past. Moreover, the success rate of fistulas is even lower for certain patient subsets. To achieve an optimal outcome with A-V fistulas, we recommend that they be constructed preferentially in the upper arm in female, diabetic, and older hemodialysis patients.

Adult↗
PubMed1998

Orbital lymphosarcoma associated with reticuloendotheliosis virus in a peafowl.

Lymphosarcoma associated with infection by avian reticuloendotheliosis virus was diagnosed in an Indian peafowl with exophthalmia and exposure keratitis. Exenteration of the orbit was complicated by a profound oculocardiac reflex and extensive hemorrhage during surgery. Orbital bleeding was controlled by direct pressure, electrocautery, topical administration of bovine thrombin, and application of sterile gelatin sponges and oxidized regenerated cellulose. A blood transfusion was also performed. In addition to describing methods of handling intraoperative complications of orbital exenteration in birds, to the authors' knowledge, this is the first report to describe an association of reticuloendotheliosis virus, which more commonly affects poultry, with lymphosarcoma in an Indian peafowl.

Animals↗
PubMed1998

Effect of intracameral administration of carbachol on the postoperative increase in intraocular pressure in dogs undergoing cataract extraction.

OBJECTIVE: To determine whether intracameral injection of carbachol at the completion of phacoemulsification in dogs would prevent the increase in intraocular pressure (i.o.p) that can develop during the first 24 hours after surgery. DESIGN: Randomized controlled trial. ANIMALS: 32 adult dogs undergoing elective unilateral or bilateral phacoemulsification. PROCEDURE: Dogs were randomly assigned to 1 of 4 groups with 8 dogs/group: phacoemulsification and intracameral administration of 0.5 ml of 0.01% carbachol at the end of surgery; phacoemulsification, intraocular lens implantation, and intracameral administration of 0.5 ml of 0.01% carbachol; phacoemulsification and intracameral administration of 0.5 ml of balanced salt solution; and phacoemulsification, intraocular lens implantation, and intracameral administration of 0.5 ml of balanced salt solution. Intraocular pressure was measured at 3 and 6 hours and the morning after surgery. Aqueous flare was also measured 6 hours and the morning after surgery. RESULTS: None of the dogs treated with carbachol developed postoperative ocular hypertension (i.e., IOP > 27 mm of Hg), whereas 12 of 16 control dogs had ocular hypertension 3 hours after surgery. Intraocular pressure 3 hours after surgery was not significantly associated with phacoemulsification time or phacoemulsification power or with whether the dog received an intraocular lens implant. Severity of aqueous flare was similar for treated and control dogs. CLINICAL IMPLICATIONS: Results suggested that intracameral administration of 0.01% carbachol at the end of surgery was a safe and efficacious method of preventing the postoperative increase in IOP associated with phacoemulsification in dogs.

Animals↗
PubMed1998

Detection of Ehrlichia risticii, the agent of Potomac horse fever, in freshwater stream snails (Pleuroceridae: Juga spp.) from northern California.

Ehrlichia DNA was identified by nested PCR in operculate snails (Pleuroceridae: Juga spp.) collected from stream water in a northern California pasture in which Potomac horse fever (PHF) is enzootic. Sequencing of PCR-amplified DNA from a suite of genes (the 16S rRNA, groESL heat shock operon, 51-kDa major antigen genes) indicated that the source organism closely resembled Ehrlichia risticii, the causative agent of PHF. The minimum percentage of Juga spp. harboring the organism in the population studied was 3.5% (2 of 57 snails). No ehrlichia DNA was found in tissues of 123 lymnaeid, physid, and planorbid snails collected at the same site. These data suggest that pleurocerid stream snails may play a role in the life cycle of E. risticii in northern California.

Amino Acid Sequence↗
PubMed1998

Photoreceptor cell death by apoptosis in dogs with sudden acquired retinal degeneration syndrome.

OBJECTIVE: To examine the role of apoptosis in retinal photoreceptor degeneration in dogs with sudden acquired retinal degeneration syndrome (SARDS). SAMPLE POPULATION: Retinas from 3 dogs with SARDS and from 2 clinically normal adult dogs. PROCEDURE: Apoptosis was identified by in situ end-labeling and observation of characteristic morphologic changes by light microscopy. RESULTS: The degree of photoreceptor degeneration varied with duration of vision loss in SARDS-affected eyes. The retina of all 3 SARDS-affected eyes had numerous (34, 61, and 70) apoptotic nuclei per section that were overwhelmingly located in the outer nuclear layer. Apoptotic nuclei were not detected, or were rare in similarly sized retinal sections from normal dogs. Inflammation was not an important feature of SARDS. CONCLUSIONS: Apoptosis appears to be at least 1 mechanism of photoreceptor cell death in dogs with SARDS. CLINICAL RELEVANCE: Because apoptosis appears to be a final common pathway in many retinal degeneration syndromes, future treatment strategies that control apoptosis in other diseases may be applicable to dogs with SARDS. Halting this pathway may allow some photoreceptors to survive and, perhaps, preserve vision.

Animals↗
PubMed1997

Mechanisms of acute intraocular pressure increases after phacoemulsification lens extraction in dogs.

OBJECTIVE: To investigate the mechanisms by which intraocular pressure (IOP) increases acutely after phacoemulsification (PE) lens extraction in clinically normal dogs. ANIMALS: 24 young adult dogs. PROCEDURE: Intraocular pressure was monitored for up to 24 hours after unilateral intercapsular PE in 17 clinically normal, adult dogs. In 8 of these dogs, use of 2% hydroxypropyl methylcellulose (HPMC) aided capsulorhexis. Mean volume of irrigation, PE time, and power were constant between groups. After surgery, dogs were randomized then euthanatized, and eyes were examined grossly and histologically at 0 (n = 4), 3 (n = 7), and 24 hours (n = 6) after PE. Seven additional dogs underwent anterior chamber decompression alone (n = 4) or served as morphologic controls (n = 3). RESULTS: Intraocular pressure peaked by postoperative hour 3 at 49.9 +/- 5.0 mm of Hg and normalized by 24 hours. Use of HPMC did not affect the peak or duration of IOP increase. Blood refluxed into the collecting channels and corneoscleral trabecular meshwork in operated eyes. Computer-aided morphologic analysis indicated significant (P < 0.001) reduction in ciliary cleft cross-sectional surface area and width immediately after PE, but not after anterior chamber decompression alone. Cleft collapse was significantly (P < 0.02) greater at 24 than at 3 hours, despite return of IOP to control values by 24 hours. Plasmoid aqueous also was found in the meshwork. CONCLUSIONS AND CLINICAL RELEVANCE: Sudden, large increases in IOP with few overt clinical signs may occur immediately after lens extraction in dogs. Such increases risk compromising the corneal incision and may damage the optic nerve, thereby complicating lens extraction. Structural alterations in the trabecular meshwork persist after IOP has normalized in 24 hours and may contribute to genesis of glaucoma in the late postoperative period.

Analysis of Variance↗
PubMed1996

Effects of topical administration of 0.5% apraclonidine on intraocular pressure, pupil size, and heart rate in clinically normal dogs.

OBJECTIVE: To evaluate the effect of 0.5% apraclonidine on intraocular pressure (IOP), pupil size, and heart rate in clinically normal dogs. DESIGN: Randomized masked saline-controlled case study. ANIMALS: Nine clinically normal conditioned adult dogs of either sex. PROCEDURE: Normal diurnal variation in IOP, pupil size, and resting heart rate were determined from 7 AM to 7 PM (day 1). These measurements were repeated on day 2 after topical application of 60 microliters of 0.5% apraclonidine to 1 randomly chosen eye of each dog. The contralateral eye received saline solution. RESULTS: Compared with the saline-treated fellow eye, mean IOP in the apraclonidine-treated eye was significantly reduced (3.0 mm of Hg, 16%) 8 hours after treatment. Because of mild day-to-day variations in IOP, however, IOP in the apraclonidine-treated eye on day 2 was not significantly different from day-1 baseline values obtained from the same eye. Significant mydriasis (2.1 mm, 29.7%), persisting for up to 8 hours, occurred in apraclonidine-treated eyes. Although apraclonidine did not significantly alter heart rate when all 9 dogs were viewed as a group, 4 dogs experienced a 9 to 19.5% reduction in heart rate 2 hours after treatment. Mild blanching of the conjunctiva occurred in apraclonidine-treated eyes. CONCLUSIONS: Apraclonidine lowered IOP and, in contrast to cats where it causes miosis, induced mydriasis in dogs. Although heart rate generally is unchanged, it may be reduced in select individuals. CLINICAL RELEVANCE: Topically applied 0.5% apraclonidine may be a useful adjunct to other antiglaucoma treatment modalities in dogs, but is unlikely to be effective as the sole agent in most forms of canine glaucoma.

Administration, Topical↗