Diagnostic benefits of platelet-to-lymphocyte, neutrophil-to-lymphocyte, and albumin-to-globulin ratios in dogs with nasal cavity diseases

BACKGROUND

A multimodal approach for diagnostic tests under anesthesia is required to diagnose nasal cavity pathology (NP) reliably in dogs. Blood test results may provide clues to the suspected NP.

METHODS

This prospective blinded study assessed 72 dogs with chronic nasal discharge due to NPs, and 10 healthy dogs as the control group (CG). NPs were diagnosed using whole-body computed tomography (CT), upper airway endoscopy, examination of nasal mucosal swabs by bacterial and fungal culture, and histopathological examination of nasal mucosa biopsies. The exclusion criteria were the presence of any additional diseases or corticosteroid pre-treatment. In consideration of these exclusion criteria, 55 dogs entered the study. Dogs were classified into benign (benign tumors, idiopathic rhinitis (IR), and others) and malignant (carcinomas and sarcomas) NP groups. Blood count and blood chemistry tests were performed. The neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), and albumin-to-globulin ratio (AGR) were calculated and compared.

RESULTS

25 dogs with malignant NP (13 and 12 with carcinomas and sarcomas, respectively) and 30 dogs with benign NP (seven with benign tumors,13 with IR, and 10 others) were included. In general, in dogs with NP there were only slight abnormalities in complete blood count. However, PLR was significantly higher in dogs with malignant NP (carcinoma and sarcoma) than in those with benign NP and in the CG. Compared with the CG, the NLR was significantly increased in all dogs with NP, and the AGR was mild but significantly lower, except in dogs with sarcomas and benign tumors.

CONCLUSIONS

In dogs with nasal disease alone, there are usually no marked abnormalities in blood count. However, while mildly increased NLR and decreased AGR can be observed in almost all NPs, an increased PLR may indicate a malignant NP and can be used as an additional screening tool in dogs with nasal discharge due to nasal cavity pathology.

[Nasal obstruction: Odontogenic cysts in 4 brachycephalic dogs]

OBJECTIVE

Odontogenic cysts may be of developmental or inflammatory origin. They are frequently observed in brachycephalic dogs. Due to their expansive growth, cysts in the maxilla may extend into the nasal cavity, obstruct the nasal airway and cause nasal discharge. Epithelial cysts may lead to a comparable clinical picture. A new endonasal endoscopic intervention for the removal of these cysts is described.

MATERIAL AND METHODS

Four brachycephalic dogs (Boxer, Chihuahua, French bulldog, Pug) with unilateral cysts obstructing the nasal cavity were included in the study. The animals underwent clinical examination, computed tomography (CT) imaging and rhinoscopy examination. Histopathologic evaluation of the cyst wall was performed. In addition to dental surgery and conventional extraction of the involved tooth, the cyst wall was removed by endoscopic intervention via the physiologic nasal opening. Clinical course following treatment was assessed by rhinoscopy and CT.

RESULTS

The main clinical signs were unilateral or bilateral serous to hemorrhagic nasal discharge. Nasal airflow was restricted in all patients. Removal of the cysts and involved teeth did not lead to any intra- and postoperative complications. No recurrence of the cysts was observed. Histologic diagnosis consisted of an epidermoid cyst, a follicular cyst, a radicular cyst, and a canine odontogenic parakeratinized cyst (COPC). Neoplastic transformation was excluded in all cases.

CONCLUSIONS

Removal of the cyst wall may be performed by means of minimally invasive endoscopic intervention via the physiologic nasal entrance. The procedure is curative and carries the risk of only few complications. In cases in which treatment is restricted to extraction of the affected tooth, the nasal airway may remain obstructed due to a calcified cyst wall.

CLINICAL RELEVANCE

In brachycephalic dogs, oronasal defects due to dental pathology are the most common reason for chronic nasal discharge, whereas in normocephalic dogs nasal neoplasia are. Odontogenic cysts carry importance as differential diagnosis of nasal discharge.

Tissue S100/calgranulin expression and blood neutrophil-to-lymphocyte ratio (NLR) in dogs with lower urinary tract urothelial carcinoma

BACKGROUND

Urothelial carcinoma (UC) is the most common neoplasm of the canine lower urinary tract, affecting approximately 2% of dogs. Elderly female patients of certain breeds are predisposed, and clinical signs of UC can easily be confused with urinary tract infection or urolithiasis. Diagnosis and treatment are challenging given the lack of disease-specific markers and treatments. The S100A8/A9 complex and S100A12 protein are Ca²⁺-binding proteins expressed by cells of the innate immune system and have shown promise as urinary screening markers for UC. The neutrophil-to-lymphocyte ratio (NLR) can also aid in distinguishing certain neoplastic from inflammatory conditions. Our study aimed to evaluate the tissue expression of S100/calgranulins and the blood NLR in dogs with UC. Urinary bladder and/or urethral tissue samples from dogs with UC (n = 10), non-neoplastic inflammatory lesions (NNUTD; n = 6), and no histologic changes (n = 11) were evaluated using immunohistochemistry. Blood NLRs were analyzed in dogs with UC (n = 22) or NNUTD (n = 26).

RESULTS

Tissue S100A12-positive cell counts were significantly higher in dogs with lower urinary tract disease than healthy controls (P = 0.0267 for UC, P = 0.0049 for NNUTD), with no significant difference between UC and NNUTD patients. Tissue S100A8/A9-positivity appeared to be higher with NNUTD than UC, but this difference did not reach statistical significance. The S100A8/A9⁺-to-S100A12⁺ ratio was significantly decreased in neoplastic and inflamed lower urinary tract tissue compared to histologically normal specimens (P = 0.0062 for UC, P = 0.0030 for NNUTD). NLRs were significantly higher in dogs with UC than in dogs with NNUTD, and a cut-off NLR of ≤ 2.83 distinguished UC from NNUTD with 41% sensitivity and 100% specificity. Higher NLRs were also associated with a poor overall survival time (P = 0.0417).

CONCLUSIONS

These results confirm that the S100/calgranulins play a role in the immune response to inflammatory and neoplastic lower urinary tract diseases in dogs, but the tissue expression of these proteins appears to differ from their concentrations reported in urine samples. Further investigations of the S100/calgranulin pathways in UC and their potential as diagnostic or prognostic tools and potential therapeutic targets are warranted. The NLR as a routinely available marker might be a useful surrogate to distinguish UC from inflammatory conditions.

Brachycephaly in French bulldogs and pugs is associated with narrow ear canals

BACKGROUND

Brachycephalic dog breeds have multiple skull malformations which may lead to anatomical changes in the external auditory canal. It is our frequent observation that in the otoscopic examination of the external ear in these breeds we are unable to visualise the tympanic membrane as a consequence of extreme narrowing of the proximal ear canal. Additionally brachycephalic dogs reportedly are predisposed to otitis externa (OE) and otitis media.

OBJECTIVES

To characterizse the transition of the cartilaginous ear canal to the bony meatus acusticus externus using computed tomography (CT) and to investigate a possible association with OE in brachycephalic dogs.

MATERIALS AND METHODS

Seventy-five client-owned dogs [pugs (n = 20), French bulldogs (n = 55)] were included and assessed for OE using an owner questionnaire and otoscopic and cytological examinations. In dorsal plane CT scans, the diameter of the porus acusticus externus was measured using novel methodology. The results were compared with a normocephalic control group without preexisting otological disorders.

RESULTS

Brachycephalic dogs had a significantly smaller porus acusticus externus diameter (2.6 mm) than normocephalic dogs (5.0 mm). Of the brachycephalic dogs, 32% had OE yet this was not statistically significantly related to the diameter of the porus acusticus externus. Middle ear effusion (44%) and narrowing of the external ear canal (82.6%) were significantly more frequent in brachycephalic dogs. Only five of 150 eardrums could be visualised otoscopically.

CONCLUSIONS AND CLINICAL RELEVANCE

Malformation of the porus acusticus externus causes severe stenosis of the proximal ear canal in brachycephalic dogs. A connection between stenosis of the external auditory canal and OE could not be confirmed.

A RAPGEF6 variant constitutes a major risk factor for laryngeal paralysis in dogs

Laryngeal paralysis (LP) is the inability to abduct the arytenoid cartilages during inspiration, resulting in a partial to complete airway obstruction and consequent respiratory distress. Different forms of LP with varying age of onset exist in dogs. Hereditary early onset forms were reported in several dog breeds. In most breeds, hereditary LP is associated with other neurologic pathologies. Using a genome-wide association study and haplotype analyses, we mapped a major genetic risk factor for an early onset LP in Miniature Bull Terriers to a ~1.3 Mb interval on chromosome 11. Whole genome sequencing of an affected Miniature Bull Terrier and comparison to 598 control genomes revealed a 36 bp insertion into exon 15 of the RAPGEF6 gene (c.1793_1794ins36). The imperfect genotype-phenotype correlation suggested a complex mode of inheritance with a major genetic risk factor involving a recessive risk allele. Homozygosity for the insertion was associated with a 10- to 17-fold increased risk for LP. The insertion allele was only found in Miniature Bull Terriers and Bull Terriers. It was absent from >1000 control dogs of other dog breeds. The insertion sequence contains a splice acceptor motif leading to aberrant splicing in transcripts originating from the mutant allele (r.1732_1780del). This leads to a frameshift and a premature stop codon, p.(Ile587ProfsTer5), removing 64% of the open reading frame. Our results suggest an important role of RAPGEF6 in laryngeal nerve function and provide new clues to its physiological significance.

Laryngeal paralysis (LP) leads to respiratory distress in affected dogs and can be fatal in severe cases. Many different forms of LP with different etiologies exist. Striking breed predispositions suggest that genetic factors contribute to some forms of LP. During the last years, dog breeders noticed an increased prevalence of an early onset LP in Miniature Bull Terriers. We mapped a major risk locus for this specific form of LP to a ~1.3 Mb interval on dog chromosome 11. Whole genome sequence analysis of an affected dog and comparison to 598 control genomes revealed a single protein-changing genetic variant in the critical interval. This variant, a 36 bp insertion into a coding exon of the RAPGEF6 gene, creates a cryptic splice site and leads to the expression of an aberrantly spliced transcript with a premature stop codon. This suggests that the insertion results in a loss-of-function allele. Dogs that are homozygous for the insertion have a 10- to 17-fold increased risk to develop LP. The genotype-phenotype association is not perfect, suggesting that other genetic and/or environmental factors also contribute to the development of LP. Our results suggest an important role of RAPGEF6 in laryngeal nerve function.

[Nasal discharge in dogs - are microbiological and histopathological examinations clinically useful?]

OBJECTIVE

Retrospective evaluation of the diagnostic value of bacterial culture of nasal mucosal swabs and histopathologic assessment of nasal mucosal biopsies in dogs with nasal discharge.

MATERIAL AND METHODS

Medical records of dogs with the predominant clinical sign of nasal discharge that were referred to the ENT Unit of the Small Animal Department between January 2015 and December 2016 were reviewed.

RESULTS

Data of 85 dogs were evaluated. On the basis of the results of computed tomography (CT), rhinoscopy, bacterial culture of a nasal mucosal swab and histopathologic examination of nasal mucosal biopsies, dogs were assigned to one of six groups of primary nasal diseases: nasal neoplasia (24/85, 28 %), oronasal defect (22/85, 26 %), idiopathic chronic rhinitis (17/85, 20 %), foreign body (8/85, 10 %), sinonasal aspergillosis (7/85, 8 %) and diseases of the planum nasale (7/85, 8 %). In brachycephalic dogs (14/85, 17 %), oronasal defects (8/14, 57 %) were the most frequent cause of nasal discharge. No cases of a primary bacterial infection of the nasal cavity were observed and, therefore, antibiotic treatment had not been successful. Nevertheless, 72 % of the dogs in this study had received prior antibiotic treatment. Secondary bacterial infec tions diagnosed via nasal mucosal swabs were not diagnostic for the underlying primary nasal diseases. Targeted biopsies of tumors obtained under endoscopic visualization may lead to a definitive diagnosis, whereas biopsies of the nasal mucosa and the type of the inflammatory infiltrate were not diagnostic.

CONCLUSIONS

Nasal discharge in dogs is frequently an indicator of an underlying severe primary nasal disease possibly leading to mortality of the affected dogs. Further diagnostics under anesthesia should be performed early in the diagnostic evaluation. Rhinoscopy as the central diagnostic is supported by CT and biopsy. Bacterial culture of the nasal discharge does not provide a diagnosis for the primary nasal disease process.

CLINICAL RELEVANCE

Without further diagnostics, antibiotic treatment of dogs presenting with nasal discharge is considered as not appropriate and can be harmful in dogs with nasal tumors or sinonasal aspergillosis. When an intranasal malignant neoplasia is suspected, endoscopic-guided biopsies of the nasal mass should be obtained, because blind nasal biopsies are associated with a high rate of false-negative results.

Correlations between specific patterns of spontaneous activity and stimulation efficiency in degenerated retina

Retinal prostheses that are currently used to restore vision in patients suffering from retinal degeneration are not adjusted to the changes occurring during the remodeling process of the retina. Recent studies revealed abnormal rhythmic activity in the retina of genetic mouse models of retinitis pigmentosa. Here we describe this abnormal activity also in a pharmacologically-induced (MNU) mouse model of retinal degeneration. To investigate how this abnormal activity affects the excitability of retinal ganglion cells, we recorded the electrical activity from whole mounted retinas of rd10 mice and MNU-treated mice using a microelectrode array system and applied biphasic current pulses of different amplitude and duration to stimulate ganglion cells electrically. We show that the electrical stimulation efficiency is strongly reduced in degenerated retinas, in particular when abnormal activity such as oscillations and rhythmic firing of bursts of action potentials can be observed. Using a prestimulus pulse sequence, we could abolish rhythmic retinal activity. Under these conditions, the stimulation efficiency was enhanced in a few cases but not in the majority of tested cells. Nevertheless, this approach supports the idea that modified stimulation protocols could help to improve the efficiency of retinal prostheses in the future.

Evaluation of Retinal Function and Morphology of the Pink-Eyed Royal College of Surgeons (RCS) Rat: A Comparative Study of in Vivo and in Vitro Methods

PURPOSE

To characterize the course of retinal degeneration in the pink-eyed RCS rat in vivo and in vitro.

METHODS

Retinal function of RCS rats at the age of 2 to 100 weeks was determined in vivo using full-field electroretinography (ERG). Retinal morphology was evaluated in vivo using spectral domain Optical Coherence Tomography (sd-OCT) and Fluorescence angiography (FA) as well as postmortem using immunohistochemistry (IH). As a control, retinal function and morphology of non-dystrophic Wistar rats were analyzed.

RESULTS

RCS rats showed an extinction of the ERG beginning with the age of 4 weeks. In the OCT, the outer part of the retina (OPR) could be clearly distinguished from the inner part of the retina (IPR) until the age of 8 weeks. However, at this age, it was impossible to determine from OCT images whether the OPR was formed by the outer nuclear layer (ONL) or by cellular debris built in the course of retinal degeneration. In contrast, immunohistochemistry always enabled to differentiate between ONL and debris (RCS 4 weeks of age: OPR mainly formed by ONL; RCS 8 weeks of age: OPR consisted mainly of cell debris, only 1-2 cell rows of photoreceptor somata were left).

CONCLUSIONS

In general, data obtained in vivo were confirmed by data obtained post mortem. Apart from the problem to differentiate between debris and ONL at the age of 8 weeks in the RCS rat, ERG and OCT are useful methods to evaluate retinal function and structure in vivo and to complement immunohistochemical analysis of the degeneration process.

Selective photoreceptor degeneration by intravitreal injection of N-methyl-N-nitrosourea

PURPOSE

To characterize the effects of intravitreal injections of N-methyl-N-nitrosourea (MNU) in comparison to its systemic application as a measure of inducing unilateral photoreceptor degeneration.

METHODS

Eight-week-old male C57BL/6J mice received either intraperitoneal injections (three animals) or intravitreal injections (24 animals) of MNU in different concentrations and were observed over a period of 2 weeks using full-field electroretinography (ERG), spectral-domain optical coherence tomography (SD-OCT), and immunohistochemistry.

RESULTS

The intraperitoneal application of MNU showed moderate systemic toxic effects, indicated by a loss of body weight of 12% within the first 2 days. In both eyes the ERG became extinguished, and SD-OCT scans showed a thinning of the retina, predominantly in the outer nuclear layer (ONL). Immunohistochemistry demonstrated the selective loss of rods and cones. Mice that received intravitreal MNU injections displayed nearly no weight loss, and no degeneration of their general welfare was observed. After 2 weeks, ERG, SD-OCT, and immunohistochemistry revealed changes identical to those seen after systemic application in the injected eye, but not in the control eye.

CONCLUSIONS

The intraperitoneal application of MNU led to moderate systemic side effects in mice and to selective photoreceptor degeneration. Intravitreal injections of MNU also induced photoreceptor degeneration; however, no systemic side effects were observed. This tool may be helpful in larger species, where genetic models of receptor degenerations are not applicable but where the size of the eye is more suitable to study surgical or other approaches to treat blindness caused by receptor degeneration.

[Der Regenbogen in Wissenschaft und Kunst]

New ideas and calculations about angles are presented, particularly about the degree of polarization of the first twenty rainbows, and it is proved why never more than two rainbows can be seen in the sky. The general sky brightness of the rainbow neighborhood is calculated with the Fresnel reflection formulas. It is shown that for certain refraction indices the first one or each of the higher rainbows can be polarized completely and that with a rising n there is an upper limit of existence for each one of them. This is clearly shown by diagrams. The standard of the exact color finding on rainbows is described with special emphasis on the fact that the loss of saturation, due to light reflected by waterdrops, must be considered. Some special features of rainbows mentioned in literature are pointed out and the importance of this phenomenon in constructive art, folklore, and religion is discussed.