Asymmetric Distributions of Achromatic Bipolar Cells in the Mouse Retina

In the retina, evolutionary changes can be traced in the topography of photoreceptors. The shape of the visual streak depends on the height of the animal and its habitat, namely, woods, prairies, or mountains. Also, the distribution of distinct wavelength-sensitive cones is unique to each animal. For example, UV and green cones reside in the ventral and dorsal regions in the mouse retina, respectively, whereas in the rat retina these cones are homogeneously distributed. In contrast with the abundant investigation on the distribution of photoreceptors and the third-order neurons, the distribution of bipolar cells has not been well understood. We utilized two enhanced green fluorescent protein (EGFP) mouse lines, Lhx4-EGFP (Lhx4) and 6030405A18Rik-EGFP (Rik), to examine the topographic distributions of bipolar cells in the retina. First, we characterized their GFP-expressing cells using type-specific markers. We found that GFP was expressed by type 2, type 3a, and type 6 bipolar cells in the Rik mice and by type 3b, type 4, and type 5 bipolar cells in the Lhx4 mice. All these types are achromatic. Then, we examined the distributions of bipolar cells in the four cardinal directions and three different eccentricities of the retinal tissue. In the Rik mice, GFP-expressing bipolar cells were more highly observed in the nasal region than those in the temporal retina. The number of GFP cells was not different along with the ventral-dorsal axis. In contrast, in the Lhx4 mice, GFP-expressing cells occurred at a higher density in the ventral region than in the dorsal retina. However, no difference was observed along the nasal-temporal axis. Furthermore, we examined which type of bipolar cells contributed to the asymmetric distributions in the Rik mice. We found that type 3a bipolar cells occurred at a higher density in the temporal region, whereas type 6 bipolar cells were denser in the nasal region. The asymmetricity of these bipolar cells shaped the uneven distribution of the GFP cells in the Rik mice. In conclusion, we found that a subset of achromatic bipolar cells is asymmetrically distributed in the mouse retina, suggesting their unique roles in achromatic visual processing.

Nasal Transmissible Venereal Tumor (TVT) in Dogs

Background: Transmissible venereal tumors (TVT) are naturally occurring neoplasms that can be transmitted through copulation or cell transplantation. It is a disease that affects canines, has no preference for sex or breed, and generally noticed in the external genital apparatus. Extragenital occurrence may eventually be seen; however, nasal involvement has been described in only a few reports of studies conducted in Brazil. Therefore, the objective of this study is to report 3 cases of nasal TVT in dogs who were treated in 2 municipalities in the mountainous region of Santa Catarina, Brazil.Cases: This case report includes 3 male mixed-breed canines of age 3-13. Only 1 of the animals was castrated. As per the medical history, some points, such as an enlarged nasal region, sneezing, nasal discharge, and hoarseness, reported by the dogs’ respective owners were similar among all the dogs. Likewise, nosebleed was observed on physical examination in all the cases. The result of cytological examination was inconclusive only in 1 case. Rhinoscopy, incisional biopsy, and histopathological examination were then performed for achieving a definitive diagnosis. In the 2 cases wherein cytology gave conclusive results, the cytological smears showed changes suggestive of TVT, such as cells with eccentric nuclei and little cytoplasm, which had vacuoles inside them. In 2 cases, radiographic examinations of the skull were also performed. The images showed changes in bone radiopacity, conformation of trabeculae with areas of bone lysis and cell proliferation, and irregularity in the contour of the nasal bone. After TVT diagnosis was confirmed, chemotherapy was initiated using vincristine at a dose of 0.75 mg/m2 for 2 cases and 0.025 mg/kg for the remaining case. The number of chemotherapy sessions and duration of treatment until the resolution of lesions and clinical signs varied as per the differences in the patients’ blood counts performed prior to each session.Discussion: TVT occurs between 1 and 7 years of life. It occurs more frequently in sexually active animals and has no preference for breed. Of the 3 cases reported herein, only one of the patients was elderly. All the patients were male mixed-breed dogs, and only 1 of them was castrated. The implantation of neoplastic cells through natural mounts, licks, scratches, or bites of affected areas are the most widely accepted reasons for the transmission of this neoplasm. With regard to the nasal presentation described in the present report, it is hypothesized that the smelling or licking of the neoplastic areas by the animal may favor cell implantation, leading to the subsequent development of a tumor. Nasal TVT should be considered as a differential diagnosis for dogs with chronic symptoms of the upper respiratory tract, such as increased local volume, nasal discharge, nosebleed, and sneezing. These signs are consistent with those described in this report. Radiographic evaluation was performed in 2 cases and both showed changes in bone radiopacity and trabeculae conformation, in addition to areas of bone lysis and cell proliferation, which are common in neoplastic processes. A presumptive diagnosis can be achieved from the medical history, clinical signs, and physical examination. Cytological and histopathological examination are the confirmatory methods; however, it is used less frequently and especially when cytological evaluation does not provide a definitive diagnosis. Antineoplastic chemotherapy with vincristine is the first-choice treatment protocol, which also proved to be effective for the patients in this report. Although TVT commonly affects the external genitalia of dogs, in the cases reported herein, it was located exclusively in the nasal region. Keywords: TVT, dog, nasal, vincristine.Título: Tumor venéreo transmissível (TVT) nasal em cãesDescritores: TVT, cão, nasal, vincristine.

Spectrum of mycobacterial pathogens responsible for head and neck tuberculosis-like presentation

Tuberculosis (TB) of the head and neck can be contained in the lymph nodes, larynx, oropharynx, salivary glands, nose and paranasal sinuses, ear, skin and skull. Head and neck TB presentations are varied in nature and thus difficult to diagnose. The clinical features, radiological findings, microbiological diagnostic modalities, surgical and medical management and outcomes of nine cases of head and neck TB are discussed in detail here, together with a thorough review of the literature. Patients presented with atypical symptoms such as discharging sinus, ear lobule swelling, otitis media, vision loss and facial weakness, long refractory otorrhoea and granulation tissue in the ear canal. We diagnosed tubercular skull base osteomyelitis (one case) and laryngeal tuberculosis (two cases), mastoid tuberculosis (one case) and non-tubercular mycobacterial infection involving the temporal bone (two cases), sino-nasal region (one case), maxilla (one cases) and ear lobule (one case) over a period of 8 months. All patients were managed successfully with a combination of surgery and a well-planned treatment regimen for non-tuberculous mycobacteria (NTM) or anti-tubercular drugs for TB. All had successful outcomes except one patient with tubercular skull base osteomyelitis who expired before the initiation of anti-tubercular therapy (ATT). High clinical suspicion followed by thorough diagnostic work-up for both TB and NTM would enable early diagnosis and complete treatment.

Clinical management of a rare Peters’ anomaly-induced secondary childhood glaucoma: A case report

Childhood glaucoma is a rare disorder that occurs from birth until teenage years caused by an abnormality of aqueous humor pathways. About 50–70% of Peters' anomaly is accompanied by secondary childhood glaucoma. The presence of glaucoma will affect the prognosis. We reported the evaluation and treatment of secondary childhood glaucoma due to Peters’ anomaly. A 5 months-old boy was presented with the complaint of a enlarged left eye since 3 months old. The complaint was accompanied by a watering eye and frequently closed upon light exposure. The left eye looked opaquer than contralateral. Examination under anesthesia showed that the intraocular pressure (IOP) was 35 mmHg in the left eye and the corneal diameter was 14 mm. Other findings were keratopathy, diffuse corneal edema, buphthalmos, shallow anterior chamber, anterior synechiae, and linear slit shaped pupils in the nasal region. Patient was treated with ophthalmic timolol maleate which was later followed by trabeculectomy. After 1 week post-surgery, IOP assessment by palpation suggested the right eye within normal range while the IOP of left eye was higger than normal. Blepharospasm, epiphora, photophobia, bleb on superior, subconjunctiva bleeding, buphthalmos, keratopathy, minimal corneal edema, anterior chamber with shallow image, and posterior synechia were found in left eye anterior segment. In conclusion, trabeculotomy and trabeculectomy are recommended if there is no reduction of IOP observed after receiving timolol maleate therapy. The choice of surgical management is dependent on the feasibility of the protocol.

Getting out of a mammalian egg: the egg tooth and caruncle of the echidna

In the short-beaked echidna, Tachyglossus aculeatus, after an initial period of in utero development, the egg is laid in the pouch and incubated for 10 days. During this time, fetuses develop an egg tooth and caruncle to help them hatch. However, there are only a few historical references that describe the development of the monotreme egg tooth. Using unprecedented access to echidna pre- and post-hatching tissues, the egg tooth and caruncle were assessed by micro-CT, histology and immunofluorescence, to map the changes at the morphological and molecular level. Unlike mammalian tooth germs that develop by invagination of a placode, the echidna egg tooth developed by evagination, similar to that of the first teeth in some reptiles. The egg tooth ankylosed to the premaxilla, rather than forming a mammalian thecodont attachment, with loss of the egg tooth post-hatching associated with high levels of odontoclasts, and apoptosis. The caruncle formed as a separate mineralisation from the adjacent nasal capsule, and as observed in birds and turtles, the nasal region epithelium expressed markers of cornification. Together, this highlights that the monotreme egg tooth shares many similarities with reptilian teeth, suggesting that this tooth is conserved from a common ancestor of mammals and reptiles.

Tubular subdermal flap to dorsal nasal reconstruction in a dolichocephalic dog: case report

This case report described the use of tubular subdermal flap to dorsal nasal reconstruction of an old dolichocephalic dog. A nine-year-old Dachshund female dog-weighing 10 kg presented with deep and extensive wound in the dorsal nasal region was attended at veterinary clinic, Sorocaba city, São Paulo, Brazil. The reconstructive surgical procedure was performed in three stages with an interval time of 25 days, which included the preparation of the tubular subdermal flap; the advance of the flap to the region of the tissue defect, and the removal of excess flap. The region healed 14 days after the last stage. The tubular subdermal flap was effective for treating ulcerative epithelial wounds associated with interstitial lymphoplasmocyte dermatitis and vasculitis of the dorsal nasal region of an old Dachshund dog.

The Layered Anatomy of the Nose: An Ultrasound-Based Investigation

Background An increasing number of soft tissue filler procedures in the nasal region has been reported. Concomitant with demand, the number of complications has risen due to the difficulty in administering filler in a region where soft tissue layering is complex. Objectives To describe the layered soft tissue arrangement of the nose as it relates to the underlying arterial vasculature and to define safer zones for nasal filler enhancement. Methods A total of 60 (28 males and 32 females) study participants were investigated with respect to their layered anatomy in the midline of the nose using ultrasound imaging. The presence and extent of the layered arrangement was examined as well as the depth of the arterial vasculature. Results In the mid-nasal dorsum, a 5-layer arrangement was observed in 100% (n= 60) of all investigated cases, whereas it was found to be absent in the nasal radix and tip. The 5-layer arrangement showed an average extent of 26.7% - 67.5% in relation to nasal length. The nasal arteries coursed superficially in 91.7% of all cases in the nasal radix, in 80% in the mid-nasal dorsum, and in 98.3% in the nasal tip. Conclusions Soft tissue filler administration in the nose carries the highest risk for irreversible vision loss compared to any other facial region. The safety of soft tissue filler rhinoplasty procedures is enhanced by knowledge of the layered anatomy of the nose, the location and depth of the major nasal vasculature, and employment of maneuvers to decrease the risk of blindness.

Quantitative analysis of retinal and choroidal vasculature in patients with chorioretinal folds secondary to hyperopia

Introduction: There is a lack of information on quantitative parameters of optical coherence tomography angiography (OCTA) in cases of chorioretinal folds (CRF). The aim of this study was to compare OCTA retinal and choriocapillary vessel density (VD) between normal subjects and patients with CRF. Methods: We conducted an observational retrospective study. A total of 16 eyes of eight patients were recruited (eight eyes with CRF and eight control eyes). Data on best-corrected visual acuity (BCVA), refractive error, central macular thickness (CMT), central subfoveal thickness (CST), and OCTA findings (VD and foveal avascular zone (FAZ) area in superficial capillary plexus (SCP), middle capillary plexus (MCP), and deep capillary plexus (DCP), and VD in choriocapillaris (CC)) were recorded in each eye. Results: Compared with control group, CRF group showed decreased VD in the foveal region of SCP and MCP ( p value 0.003 and 0.001), and increased VD in nasal region of SCP and MCP ( p value 0.02 and 0.001), and in parafoveal area of MCP ( p value 0.005). No differences were found in DCP and CC layers. Furthermore, we observed an enlargement of FAZ in CRF group at SCP and MCP slabs ( p value <0.001 and 0.015). Respect to optical coherence tomography parameters, we demonstrated a thicker choroid in the CRF group ( p value 0.002). Conclusion: To the best of our knowledge, this is the first study reported in the literature quantifying VD of retinal capillary plexus and CC in a group of patients with a diagnosis of CRF secondary to hyperopia.