Oscillating potentials on the B-wave of the ERG in the dog]

The oscillatory potentials (OP) on the b-wave of the canine ERG are characterized. Normal values for an OP-index, implicit times and periodicity are given. The OP-index increases during dark adaptation as well as with increasing stimulus intensities for white light flashes. Scotopic blue and red stimuli, although balanced for the maximum b-wave amplitude, surprisingly result in higher OP-indices for red flashes. Implicit times decrease for all OP with increasing stimulus intensities. Scotopic balanced red light results in OP with markedly reduced implicit times compared to blue light stimulation. The intervals between two OPs remain constant during dark adaptation, however, intervals between OPs with longer implicit times tend to be shorter. In contrast, the b-waves for scotopic balanced stimuli show rhythmic oscillations with constant intervals between them, the intervals being shorter for blue light than for red light. The intervals between OPs tend to become shorter with increasing stimulus intensities. This investigation indicates that OPs are influenced but not generated by photoreceptors. The examination of a dog with optic nerve hypoplasia indicates that the ganglion cells do not contribute to the biogenesis of OPs. The prognostic value of OPs in the early diagnosis for hereditary retinal degenerations in the dog is discussed.     

Keratitis due to Histoplasma spp. in a horse

A 5-year-old Holsteiner gelding from Germany was presented 2 months after a whitish discoloration of the left cornea was observed. Cytologic examination revealed intra- and extracellular globular structures, up to 4 micro m in size, consisting of a central spherical deeply basophilic body surrounded by an unstained halo. The structures were morphologically consistent with Histoplasma spp. Infection with Histoplasma organisms is not endemic in Europe. Topical use of fluconazole was successful in eliminating Histoplasma organisms within 10 days of initiation of treatment.     

East pacific rise crest: a near-bottom geophysical profile

A deep-towed magnetometer profile made across the East Pacific Rise crest shows many anomalies with about 1000-gamma amplitudes and 500-meter wavelengths and has larger amplitude changes corresponding to magnetic field reversals. This profile across contacts between normal and reversely magnetized crustal blocks is interpreted to place an upper limit of 4700 years on the time required for field reversals and an upper limit of 280 meters on the width of the intrusion center at the rise crest. This intrusion center may occasionally shift several kilometers laterally with respect to the rise axis. The magnetometer records are compatible with the hypothesis that the magnetic field has undergone many fluctuations of short period and small intensity in the past 2 million years. Sediment accumulation increases from less than 2 meters at the rise crest axis to about 20 meters at the western end and 10 meters at the eastern end of the profile. This increase in accutmiulation appears to be the result of ocean-floor spreading.     

Production of an epidermal growth factor receptor-related protein

Human epidermoid carcinoma A431 cells in culture produce a soluble 105-kilodalton protein which, by the criteria of epidermal growth factor (EGF) binding, recognition by monoclonal and polyclonal antibodies to the EGF receptor, amino-terminal sequence analysis and carbohydrate content, is related to the cell surface domain of the EGF receptor. The high rate of production and the finding that with biosynthetic labeling the specific activity of this 105-kilodalton protein exceeds that of the intact receptor indicate that it is not derived from membrane-bound mature receptor but is separately produced by the cell. These cells thus separately synthesize an EGF receptor that is inserted into the membrane and an EGF receptor-related protein that is secreted.     

Epidemiology of canine glaucoma presented to University of Zurich from 1995 to 2009. Part 2: secondary glaucoma (217 cases)

Objective To investigate the epidemiology of canine secondary glaucomas in the cases presented to the University of Zurich, Vetsuisse Faculty (UZH) from 1995 to 2009 focusing on possible risk factors for developing secondary glaucoma in this population of dogs. Methods Information was obtained from the computer database of patients examined by members of the UZH Ophthalmology Service, between January 1995 and August 2009. Secondary glaucoma was diagnosed based on the presence of antecedent eye conditions. The data was evaluated for breed, gender, age at presentation, and for antecedent eye conditions known to cause glaucoma including anterior uveitis of unknown cause (AU), lens luxation (LL), intraocular surgery (SX), intraocular neoplasia (IN), unspecified trauma to the globe (T), ocular melanosis (OM), hypermature cataract (PY), hyphema (HY), and six other less frequent conditions. Results A total of 217 dogs were diagnosed with secondary glaucoma from 1995 to 2009. The age of the dogs with secondary glaucoma ranged between 88 days and 19 years (mean 7.7 ± 3.6 years). Data suggested a predisposition for secondary glaucoma in the Cairn Terrier and the Jack Russell Terrier breeds from 2004 to 2009. Common causes of secondary glaucoma from 1995 to 2009 were AU (23.0%), LL (22.6%), SX (13.4%), IN (10.6%), T (8.3%), OM and PY (both 6.9%) and HY (3.23%). Conclusion The report presents the epidemiology of secondary glaucomas presented to UZH from 1995 to 2009. Fourteen risk factors were recorded for secondary glaucoma. This is the first paper documenting OM in the Swiss Cairn Terrier dog population.     

Epidemiology of canine glaucoma presented to University of Zurich from 1995 to 2009. Part 1: Congenital and primary glaucoma (4 and 123 cases)

Objective To investigate the epidemiology of canine congenital and primary glaucoma in the cases presented to the University of Zurich, Vetsuisse Faculty (UZH) from 1995 to 2009. Methods Information was obtained from the computer database of patients examined by members of the UZH Ophthalmology Service, between January 1995 and August 2009. Congenital and primary glaucoma was diagnosed based on the age of onset, the lack of evidence of any antecedent eye conditions, and/or the presence and severity of iridocorneal angle defects. The data was evaluated for breed, gender and age at presentation. Results A total of 5984 dogs presented to the UZH Ophthalmology service between 1995 and 2009. Four dogs of different breed were diagnosed with congenital glaucoma and 123 dogs were diagnosed with primary glaucoma. For the primary glaucomas the overall male to female ratio (M:F) was 1:1.41 and the age of onset ranged from 0.12 to 18.3 years with a mean of 7.3 ± 3.6 years. Data suggested a predisposition for primary glaucoma in the Siberian Husky, Magyar Vizsla and Newfoundland from 2004 to 2009. Conclusion The report presents the epidemiology of canine congenital and primary glaucomas presented to the UZH from 1995 to 2009. A previous suspicion of predisposition for primary glaucoma in the Newfoundland dog (n = 6) and the Magyar Vizsla breed (n = 8) was confirmed.