CAT Spaces Research Articles

Tumours involving the retrobulbar space in cats: 37 cases.

The aim of this multicentre retrospective study was to describe the clinical presentation, imaging findings, diagnosis and outcomes of cats with retrobulbar neoplasia. A total of 37 cats that were diagnosed with retrobulbar neoplasia and underwent advanced imaging were recruited from searches of the clinical records of two referral hospitals. All cats had neoplasia confirmed via cytology or histopathology. Data relating to the signalment, presentation, results of investigations, treatment and outcome were recorded. A review of imaging studies was performed where possible. In total, 23 cases (62%) were presented with respiratory signs. Exophthalmos was the most common ophthalmological examination finding, present in 18 cases (49%). Thirty-two cases (86%) had secondary extension of neoplasia to the retrobulbar space (most commonly from the nasal cavities), present in 20 cases (54%), of which 12 were lymphoma. In cases where contrast was administered, 28/35 (80%) had contrast-enhancing masses. Orbital extension was detected in 21 cases (57%), exophthalmos in 22 (59%), globe deformation in 12 (32%) and local lymphadenomegaly in 22 (61%). In total, 36 (97%) retrobulbar tumours were malignant. Thoracic imaging, where it was performed, was concerning for metastasis in 8/25 cases (31%), with abdominal imaging suggestive of metastasis in 5/12 (42%). The most common diagnosis was lymphoma with 19 cases (51%), with nasal lymphoma representing 12 of these, followed by carcinoma in 10 (27%). The median survival time, for cases where death was recorded, was 85 days (range 1-263 days). To the authors' knowledge, this is the largest study of neoplasia affecting the feline retrobulbar space. Retrobulbar tumours in cats are overwhelmingly malignant, and commonly due to secondary extension of tumours originating elsewhere. Lymphoma, particularly arising from the nasal cavities, was the most common cause. Cats presenting with signs suggestive of retrobulbar disease should be assessed for disease affecting any of the structures of the head.

A Study on Cat in the Rain from the Perspective of Spatial Criticism

Hemingway’s short story Cat in the Rain highlights the themes of the novel with a large number of spatial images and depicts the connotation of gender conflict. As an extension of the study of space criticism, this paper analyzes the abstract meaning of landscape space, social space and individual space in Cat in the Rain, interprets the characters’ thoughts and feelings, as well as explains the complex mentality of the female character’s desire, courage, failure and return exposed in the process of her pursuit of self and freedom. Hemingway’s skillful grasp of women’s psychological reality can be proved through detail analysis.

Introduction of a Simple and Minimally Invasive Approach for Access to Epidural Space in Cat

Background: Although various studied have been done to improve therapeutic strategies in resolving spinal cord injuries, robust clinical treatment is not yet available. Developing a standard animal model is essential to achieve effective treatment for such injuries. The present study was performed to introduce a simple, applicable, and minimally invasive approach for access to epidural space in cats. Methods: We used a percutaneous approach from the lumbosacral junction for stainless steel cannula insertion to the epidural space without fluoroscopy. CT scan, conventional magnetic resonance imaging (MRI), tractography, and behavioral evaluation were used to assess the correct position of the cannula and the neurological condition of the animal. Results: MRI results showed no significant change in signal intensity index of neural structures under lumbosacral junction. These observations are further supported by tractography, and also behavioral examination during the study. Conclusion: We found that the percutaneous approach from the lumbosacral junction is a simple and applicable approach that has no side effects and artifact formation in MRI evaluation.

COMPARATIVE THREE DIMENSIONAL COMPUTED TOMOGRAPHY (CT) SCANS AND ANATOMICAL INVESTIGATION OF RABBIT (Oryctolagus cuniculus) AND CAT (Felis domestica) SKULL

This study was conducted to elucidate the comparative anatomical features of the skull of rabbits and cats using CT scans. Adult healthy New Zealand rabbits and Domestic Baladi cats of both sexes, were prepared for X-ray and CT scan of the heads at different positions. The heads were also processed for bone preparation and were photographed at various views. Some measurements were taken to exhibit the main differences between the two animal species. There was a cranial pharyngeal canal in the basisphenoid bone of rabbit, which was absent in cat. The retroarticular process situated caudal to the mandibular fossa in cat and absent in rabbit. The carotid foramen was large and situated only in rabbit ventromedial to the bulla tympanica. The supraorbital process of rabbit extended anteriorly and posteriorly forming rostral and caudal supraorbital fissures. The orbit was located laterally in rabbit rostrally in cat. The facial surface of the maxilla was perforated by several formina in rabbit. A large retroalveolar foramen was found only in the mandible of rabbit. The condyloid process of the mandible was large and present longitudinally in rabbit and transversally in cat. Also, the hyoid bones and the paranasal sinuses were compared at both animals. The hyoid bone located in the mandibular space in rabbit and caudal to this space in cat. The lingual process of the hyoid bone was absent in cat. The middle and great cornuae of the hyoid bone were absent in rabbit. The paranasal sinuses of rabbit were maxillary and ethmoidal sinuses. While in cat, there were frontal, sphenoidal and maxillary sinuses. The combination between the traditional gross morphology of the skulls, X-ray and scan aimed to clarify and confirm all the points of comparison between the two animal species used, which was not achieved by using only one method of them.Key words: rabbit; cat; skull; computed tomography; anatomy

SEMANTIČKA INTERPRETACIJA PROSTORA U DRAMI "MAČKA NA USIJANOM LIMENOM KROVU" TENESIJA VILIJAMSA

Ovaj rad ima za cilj da odredi modelativnu funkciju prostornih odnosa u drami Mačka na usijanom limenom krovu američkog dramskog pisca Tenesija Vilijamsa. Slijedeći relevantne teorije drame, u radu se pošlo od pretpostavke da je prostor u dramskom djelu bitan ne samo kao mjesto odigravanja radnje, već i kao kontekst i izvor semantičkih značenja događaja koji se u njemu zbivaju. U okviru analize prostorne konfiguracije navedenog dramskog djela razmatran je proces upisa prostora u priču, a osnovne prostorne relacije koje su u drami semantički ispitivane su scena kao prostor u kome se odigrava radnja vidljiva publici i prostor radnje van scene, odnosno dramski prostor kao najširi semantički okvir djela. Na kraju, analizirane su metaforičke kvalitete prostora fikcije. Semiotičkom analizom prostornog sistema pomenutog djela, pokazalo se da je ovaj dramski prostor dinamičan i da djeluje na više razina. U pomenutoj drami Vilijams je scenski prostor organizovao veoma jednostavno i predstavio ga samo jednim scenskim toposom u čijem centru se nalazi bračni krevet kao središnje mjesto ne samo scene, nego i semiološkog značaja djela. Međutim, u ovoj drami prostor je daleko od jednostavnog i predstavljen je veoma složenim sistemom.

Effective results on nonlinear ergodic averages in CAT spaces

In this paper we apply proof mining techniques to compute, in the setting of CAT$(\unicode[STIX]{x1D705})$ spaces (with $\unicode[STIX]{x1D705}>0$), effective and highly uniform rates of asymptotic regularity and metastability for a nonlinear generalization of the ergodic averages, known as the Halpern iteration. In this way, we obtain a uniform quantitative version of a nonlinear extension of the classical von Neumann mean ergodic theorem.

Differential targeting of feline photoreceptors by recombinant adeno-associated viral vectors: implications for preclinical gene therapy trials.

The cat is emerging as a promising large animal model for preclinical testing of retinal dystrophy therapies, for example, by gene therapy. However, there is a paucity of studies investigating viral vector gene transfer to the feline retina. We therefore sought to study the tropism of recombinant adeno-associated viral (rAAV) vectors for the feline outer retina. We delivered four rAAV serotypes: rAAV2/2, rAAV2/5, rAAV2/8 and rAAV2/9, each expressing green fluorescent protein (GFP) under the control of a cytomegalovirus promoter, to the subretinal space in cats and, for comparison, mice. Cats were monitored for gene expression by in vivo imaging and cellular tropism was determined using immunohistochemistry. In cats, rAAV2/2, rAAV2/8 and rAAV2/9 vectors induced faster and stronger GFP expression than rAAV2/5 and all vectors transduced the retinal pigment epithelium (RPE) and photoreceptors. Unlike in mice, cone photoreceptors in the cat retina were more efficiently transduced than rod photoreceptors. In mice, rAAV2/2 only transduced the RPE whereas the other vectors also transduced rods and cones. These results highlight species differences in cellular tropism of rAAV vectors in the outer retina. We conclude that rAAV serotypes are suitable for use for retinal gene therapy in feline models, particularly when cone photoreceptors are the target cell.

Cortical activation following chronic passive implantation of a wide-field suprachoroidal retinal prosthesis

Objective. The research goal is to develop a wide-field retinal stimulating array for prosthetic vision. This study aimed at evaluating the efficacy of a suprachoroidal electrode array in evoking visual cortex activity after long term implantation. Approach. A planar silicone based electrode array (8 mm × 19 mm) was implanted into the suprachoroidal space in cats (ntotal = 10). It consisted of 20 platinum stimulating electrodes (600 μm diameter) and a trans-scleral cable terminated in a subcutaneous connector. Three months after implantation (nchronic = 6), or immediately after implantation (nacute = 4), an electrophysiological study was performed. Electrode total impedance was measured from voltage transients using 500 μs, 1 mA pulses. Electrically evoked potentials (EEPs) and multi-unit activity were recorded from the visual cortex in response to monopolar retinal stimulation. Dynamic range and cortical activation spread were calculated from the multi-unit recordings. Main results. The mean electrode total impedance in vivo following 3 months was 12.5 ± 0.3 kΩ. EEPs were recorded for 98% of the electrodes. The median evoked potential threshold was 150 nC (charge density 53 μC cm−2). The lowest stimulation thresholds were found proximal to the area centralis. Mean thresholds from multiunit activity were lower for chronic (181 ± 14 nC) compared to acute (322 ± 20 nC) electrodes (P < 0.001), but there was no difference in dynamic range or cortical activation spread. Significance. Suprachoroidal stimulation threshold was lower in chronic than acute implantation and was within safe charge limits for platinum. Electrode-tissue impedance following chronic implantation was higher, indicating the need for sufficient compliance voltage (e.g. 12.8 V for mean impedance, threshold and dynamic range). The wide-field suprachoroidal array reliably activated the retina after chronic implantation.

Use of electrical nerve stimulation to monitor lumbosacral epidural needle placement in cats

ObjectiveTo determine the minimal electrical threshold (MET) necessary to elicit muscle contraction of the pelvic limb or tail when an insulated needle is positioned outside (METout) and inside (METin) the lumbosacral epidural space in cats. Study designProspective, blinded study. AnimalsTwelve mixed-breed healthy adult cats, scheduled for a therapeutic procedure where lumbosacral epidural administration was indicated. MethodsUnder general anesthesia, an insulated needle was advanced through tissues of the lumbosacral interspace until its tip was thought to be just dorsal to the interarcuate ligament. An increasing electrical current (0.1 ms, 2 Hz) was applied through the stimulating needle in order to determine the MET necessary to obtain a muscle contraction of the pelvic limb or tail (METout), and then 0.05 mL kg−1 of iohexol was injected. The needle was further advanced until its tip was thought to be in the epidural space. The MET was determined again (METin) and 0.2 mL kg−1 of iohexol was injected. The cats were maintained in sternal position. Contrast medium spread was determined through lateral radiographic projections. ResultsThe radiographic study confirmed the correct needle placement dorsal to the interarcuate ligament in all cats. When the needle was placed ventrally to the interarcuate ligament, iohexol was injected epidurally in ten and intrathecally in two cats. The METout and METin was 1.76 ± 0.34 mA and 0.34 ± 0.07 mA, respectively (p < 0.0001). Conclusion and clinical relevanceNerve stimulation can be employed as a tool to determine penetration of the interarcuate ligament but not the piercing of the dura mater at the lumbosacral space in cats.

Common fixed point theorems for some generalized non-expansive mappings and non-spreading mappings in CAT(0) spaces

We study the existence of a common fixed point for some generalized non-expansive mappings and non-spreading mappings in CAT(0) spaces. We also study an iterative method for approximating common fixed point of a pair of those mappings. Key words: CAT(0) Space, nonspreading mapping, common fixed point.

Movements and space use of feral cats in Kerguelen archipelago: a pilot study with GPS data

The domestic cat has been introduced on several sub-Antarctic islands such as the Kerguelen archipelago (48°28′–50°S, 68°28′–70°35E), causing a worrying impact on the viability of some seabird populations. A better understanding of the biology of this introduced predator is needed to help design appropriate management actions. To investigate the effectiveness of a GPS study on feral cats living on the Kerguelen main island and to gain preliminary results on cat space use and fine-scale movement patterns, we fitted GPS collars on three young adult males and recorded cat location at a high frequency (every 5 min) for 2–3 weeks, during the austral summer. Home-range sizes varied from 0.30 to 0.73 km², with large overlaps in space but not in time. Cats were active during the warmest hours of the day, with a peak of activity around 2:00 p.m. This preliminary result suggests that trapping for management of the population should therefore yield the highest number of captures in the afternoon and before sunrise, when cats are more active. Our pilot study demonstrated the potential of using GPS to track feral cats in sub-Antarctic islands, opening up opportunities to get deep insights in the spatial ecology of these introduced predators.

Dual time point based quantification of metabolic uptake rates in 18F-FDG PET

BackgroundAssessment of dual time point (DTP) positron emission tomography was carried out with the aim of a quantitative determination of Km, the metabolic uptake rate of [18F]fluorodeoxyglucose as a measure of glucose consumption.MethodsStarting from the Patlak equation, it is shown that , where mt is the secant slope of the tissue response function between the dual time point measurements centered at t = t0. denotes arterial tracer concentration, is an estimate of the Patlak intercept, and τa is the time constant of the ca(t) decrease. We compared the theoretical predictions with the observed relation between and Km in a group of nine patients with liver metastases of colorectal cancer for which dynamic scans were available, and Km was derived from conventional Patlak analysis. Twenty-two lesion regions of interest (ROIs) were evaluated. ca(t) was determined from a three-dimensional ROI in the aorta. Furthermore, the correlation between Km and late standard uptake value (SUV) as well as retention index was investigated. Additionally, feasibility of the approach was demonstrated in a whole-body investigation.ResultsPatlak analysis yielded a mean Vr of ml/ml. The patient averaged τa was 99 ± 23 min. Linear regression between Patlak-derived Km and DTP-derived Ks according to Ks = b · Km + a yielded b = 0.98 ± 0.05 and a = -0.0054 ± 0.0013 ml/min/ml (r = 0.98) in full accordance with the theoretical predictions b = 1 and . Ks exhibits better correlation with Km than late SUV and retention index, respectively. is proposed as a quantitative estimator of Km which is independent of patient weight, scan time, and scanner calibration.ConclusionQuantification of Km from dual time point measurements compatible with clinical routine is feasible. The proposed approach eliminates the issues of static SUV and conventional DTP imaging regarding influence of chosen scanning times and inter-study variability of the input function. Ks and exhibit improved stability and better correlation with the true Km. These properties might prove especially relevant in the context of radiation treatment planning and therapy response control.

Distribution of new methylene blue injected into the lumbosacral epidural space in cats

ObjectiveTo determine the effects of injection volume and vertebral anatomy on the spread of new methylene blue (NMB) injected into the lumbosacral epidural space in cats. Study designProspective experimental study. Sample populationSixteen cats. MethodsCats were randomly assigned to four groups and received from 0.1 to 0.4 mL kg−1 of 0.12% NMB in 0.9% saline. Injection was made into the lumbosacral epidural space using a dorsal approach with the cats in sternal recumbency. The extent of cranial migration of the dye as indicated by the staining of epidural fat and dura mater was measured. ResultsThe mean ± SD (range) number of stained vertebrae in the 0.3 and 0.4 mL kg−1 groups, were 11.5 ± 1.5 (T7–T11) and 12.4 ± 1.8 (T6–T10), respectively. This was significantly greater than the number in the 0.1 and 0.2 mL kg−1 groups, 4.3 ± 0.6 (L3–L4) and 6.0 ± 0.7 (L1–L2) vertebrae, respectively (p < 0.001). Linear regression analysis showed that the volume injected correlated significantly with the number of stained vertebrae (R2 = 0.83, p < 0.001). In the dorsal and lateral aspect of the spinal cord, NMB solution distributed between epidural fat and dura mater. Migration under the spinal cord occurred along the two longitudinal epidural veins. Conclusions and clinical relevanceThe larger the volume of solution injected into the lumbosacral epidural space in cats, the greater the spread.

Why cats pace on the treadmill

There have been many studies suggesting that locomotion on a treadmill tends to be different than locomotion at similar velocities overground, but no satisfactory mechanical or neural mechanisms to account for the differences have been identified. The most prominent difference is the tendency to adopt a pacing gait for both walking and trotting speeds, in which the legs on one side of the body move in phase as lateral couplets rather than the typical diagonal couplet pattern seen overground. Using conventional video analysis, we quantified the gait patterns of intact, adult cats walking at various speeds overground and in a motorized treadmill. We noted that cats paced most frequently when they were at the front end of the treadmill enclosure, and that this gait was associated with an extended stride length that permitted the animals to maintain a higher duty factor of support (mean number of feet on the ground). We propose that the animal extends its stride specifically to improve the duty factor in anticipation of sudden stops of the treadmill belt and that it converts abruptly from diagonal to lateral gait because the extended stride results in collisions between ipsilateral hind and front feet.

Comparative experimental evaluation of several types of emulsified oily radiopaque materials in the cranial subarachnoid space.

In previous papers the authors (Kerckhoffs et al. 1966; Penning et al. 1966) reported experimental evaluation of emulsified iophendylate (Pantopaque, Ethiodan) in the cranial subarachnoid space. It was shown that the emulsion had a toxic effect on the cranial nervous system of rabbits, manifesting itself in the form of convulsions, paresis, and death. Nonemulsified iophendylate, however, proved to have no toxic effect. The toxicity was not caused by the emulsifying agents, but appeared to be directly related to the degree of dispersion of the emulsion. It was concluded that iophendylate itself possessed latent toxic properties which were enhanced by the emulsification. Previous investigations with emulsified iophendylate were reported by Pirkey et al. (1950), Jaeger (1950), Nosik (1951), Portera-Sanchez et al. (1964), Fisher (1965), Kunz et al. (1965), Maupin et al. (1966), and others. These investigators all agree on the good radiographic qualities of the emulsion in comparison with the nonemulsified iophendylate. With respect to the toxic properties opinions diverge, but most investigators conclude that the toxicity of the contrast agent is increased significantly after emulsification. Because of the good radiographic qualities of emulsified radiopaque oils, especially in ventriculography and myelography (Nosik, Matsubara and Nomura, Portera, Obrador, Reyes et al.), the toxicity of emulsified iophendylate was a disappointing finding, because it obviates clinical application. We therefore planned to evaluate the toxic effect of emulsions of other oily radiopaque materials, hoping to find a lower or absent toxicity which would justify its use in clinical practice. Emulsions of iodized oil with sodium lauryl sulfate as emulsifier were used by Matsubara and Nomura (1960) in ventric-ulography in man. After the radiographic procedures, the emulsion was withdrawn from the ventricles. Side-reactions were temporary fever, appearing after several hours, slight headache, and, infrequently, nausea and vomiting. Experimental use of emulsified iodized oil was also reported by Jaeger. He prepared emulsions with acacia and blood serum. Injection into the lumbar subarachnoid space, the grand cistern, and the cerebral ventricles of dogs caused the death of almost all animals within twenty-four hours to two weeks. Moreover, after injection via the lumbar route, paralysis was seen. A more recent type of oily radiopaque is Ethiodol (Lipiodol Ultra Fluid, Iodetryl, the ethyl ester of the iodized fatty acids of poppy-seed oil), a product of the research toward increasing the fluidity of classical Lipiodol. Fisher demonstrated that lumbar injections of Ethiodol emulsions, prepared with lecithin, into the subarachnoid space in cats were well tolerated. The results showed a satisfactory contrast, no demonstrable toxicity, and essentially complete absorption after myelography.

THE DETERMINATION OF SODIUM, POTASSIUM, CALCIUM AND MAGNESIUM IN THE BLOOD AND SPINAL FLUID OF PATIENTS SUFFERING FROM MANICDEPRESSIVE INSANITY

Ringer in a number of papers beginning in 1880 showed the necessity for a proper balance between sodium, potassium and calcium in the fluids of organisms. Loeb, in 1889, showed that electrolytes cause twitching of the muscles while nonelectrolytes have no such effect, and in many subsequent papers pointed out the necessity of physiologically balanced solutions. Howell, in 1898, emphasized the importance of calcium in relation to various activities of the organism. Weed and Wegeforth,1while studying the effects of irrigation of the subarachnoidian space in cats, noted a peculiar psychic disturbance following the use of sodium chlorid solution. They first used a modified Ringer's solution made up of sodium chlorid, 0.9 per cent.; calcium chlorid, 0.024 per cent., and potassium chlorid, 0.042 per cent. The subarachnoidian space from the vertex area or the cysterna magna to the lumbar area was irrigated with this fluid. The time required was