Suspected Limbic Encephalitis and Seizure in Cats Associated with Voltage‐Gated Potassium Channel (VGKC) Complex Antibody

Background

Treatment‐resistant complex partial seizures (CPS) with orofacial involvement recently were reported in cats in association with hippocampal pathology. The features had some similarity to those described in humans with limbic encephalitis and voltage‐gated potassium channel (VGKC) complex antibody.

Hypothesis/Objectives

The purpose of this pilot study was to evaluate cats with CPS and orofacial involvement for the presence of VGKC‐complex antibody.

Animals

Client‐owned cats with acute orofacial CPS and control cats were investigated.

Methods

Prospective study. Serum was collected from 14 cats in the acute stage of the disease and compared with 19 controls. VGKC‐complex antibodies were determined by routine immunoprecipitation and by binding to leucine‐rich glioma inactivated 1 (LGI1) and contactin‐associated protein‐like 2 (CASPR2), the 2 main targets of VGKC‐complex antibodies in humans.

Results

Five of the 14 affected cats, but none of the 19 controls, had VGKC‐complex antibody concentrations above the cut‐off concentration (>100 pmol/L) based on control samples and similar to those found in humans. Antibodies in 4 cats were directed against LGI1, and none were directed against CASPR2. Follow‐up sera were available for 5 cats in remission and all antibody concentrations were within the reference range.

Conclusion and Clinical Importance

Our study suggests that an autoimmune limbic encephalitis exists in cats and that VGKC‐complex/LGI1 antibodies may play a role in this disorder, as they are thought to in humans.     

Feline Temporal Lobe Epilepsy: Review of the Experimental Literature

Accumulating evidence suggests that epileptic seizures originating from the temporal lobe (TL) occur in cats. Typically, affected animals have clinically focal seizures with orofacial automatisms including salivation, facial twitching, lip smacking, chewing, licking, and swallowing. Motor arrest and autonomic and behavioral signs also may occur. Many affected cats have magnetic resonance imaging (MRI) changes within the hippocampus or histopathologically confirmed hippocampal sclerosis or necrosis. From the 1950s to the 1980s, cats frequently were used as animal models for neurophysiological experiments and electrophysiological studies, from which important basic knowledge about epilepsy originated, but which has been rarely cited in clinical veterinary studies. These studies were reviewed. Experimental research on cats showed the widespread anatomical connections among TL structures. The ictal clinical signs originating from the hippocampus, amygdala, or lateral temporal cortex are similar, because of their dense interconnections. The ictal signs can be divided into autonomic, somatic, and behavioral. For research purposes, a 6‐stage system was established, reflecting the usual sequential progression from focal to generalized seizure: attention response (1), arrest (2), salivation, licking (3), facial twitching (4), head turning or nodding (5), and generalized clonic convulsions (6). Knowledge of this data may help in recognizing low‐stage (stage 1 or stage 2) epileptic seizures in clinical practice. Early experimental research data are in accordance with recent clinical observations regarding ictal clinical signs of TL epileptic seizures in cats. Furthermore, the research data supports the idea that TL epilepsy represents a unique clinical entity with a specific seizure type and origin in cats.     

Holography

Research on holography has now grown to such dimensions that we have not been able to mention each of the numerous authors who have made significant contributions to it. Investigators from Bell Telephone Laboratories, the RCA, Xerox, and Westinghouse laboratories, Conductron Corporation, GC-Optronics, IBM, TRW Systems, the University of Michigan, and Stanford University have made particularly significant early contributions in the United States. Especially notable were the efforts of R. J. Collier, L. Lin, K. S. Pennington, D. Ansley, L. Siebert, R. M. Grant, A. Lohmann, R. F. Wuerker, K. Stetson, R. Powell, J. Goodman, and their co-workers, in addition to those already mentioned, among many others. Early work in many parts of the world also includes that in France by S. Lowenthal, G. Nomarski, and J. Viepsilonnot; in Germany by H. Nassenstein; in Great Britain by J. M. Burch; in Japan by J. Tsujiuchi and T. Tsuruta; and in the Soviet Union by Yu. Y. N. Denisyuk, I. Nalimov, and L. M. Soroko. For a fuller account of these developments, see (42) and other references.     

Dicoumarol toxicity in neonatal calves associated with the feeding of sweet vernal (Anthoxanthum odoratum) hay

Neonatal calves from a seasonal dairy herd in North Western Tasmania were presented for veterinary care due to mortalities and bleeding from multiple orifices. Necropsy examination revealed free blood throughout the parenchymatous organs, body cavities and connective tissues. There was no history of anticoagulant exposure, however, high quantities of dicoumarol were found in samples from hay fed to recently calved cows. No Australian cases of dicoumarol toxicity in neonatal calves have been previously documented, and dicoumarol toxicity in adult cattle would appear to be less common than in colder farming regions of the Northern Hemisphere.     

Therapy for Australian cats with lymphosarcoma

OBJECTIVE: To determine the response of Australian cats with lymphosarcoma to chemotherapy and/or surgery in relation to patient and tumour characteristics, haematological and serum biochemical values and retroviral status. DESIGN: Prospective study of 61 client-owned cats with naturally-occurring lymphosarcoma subjected to multi-agent chemotherapy and/or surgery. PROCEDURE: An accepted chemotherapy protocol utilising l-asparaginase, vincristine, cyclophosphamide, doxorubicin, methotrexate and prednisolone was modified and used to treat 60 cats with lymphosarcoma. Clinical findings were recorded before and during therapy. As far as practical, cases were followed to death, euthanasia or apparent cure. Owner satisfaction with the results of chemotherapy was determined using a questionnaire sent after the completion of chemotherapy. RESULTS: One cat, with lymphosarcoma limited to a single mandibular lymph node, was treated using surgery alone and was cured. The other 60 cats were treated using multi-agent chemotherapy, although seven cats with localised intestinal, ocular and subcutaneous lesions had these lesions partially (2 intestinal lesions) or completely (2 eyes, 2 intestinal lesions and a cluster of regional lymph nodes) resected prior to starting chemotherapy. The median survival time for these 60 cats was 116 days. Of the 60 cats, 48 rapidly went into complete remission following the administration of 1-asparaginase, vincristine and prednisolone (complete remission rate 80%) and these cats had a median survival of 187 days. Three cats were censored from further analysis as their long-term survival data were uninterpretable because they died of causes unrelated to lymphosarcoma or were prematurely lost to follow-up. Twenty cats were classed as 'long-term survivors' based on survival time in excess of one year and at least 14 were 'cured' based on the absence of physical evidence of lymphosarcoma 2-years after initiating treatment. In other words, of the 48 cats that reached complete remission, in excess of 29% were 'cured'. Despite detailed analysis, few meaningful prognostic indicators based on patient or tumour characteristics were identified, although long-term survivors were more likely to be less than 4-years (P= 0.04) and to have tumours of the T-cell phenotype (P= 0.06). Excluding the one FeLV ELISA-positive cat with mediastinal LSA, 7 of 9 cats less than 4 years-of-age were long-term survivors (median survival time >1271 days). There was a strong association between achieving complete remission and long-term survival (P = 0.003). On the basis of 27 replies to a questionnaire, owners were generally very satisfied with the response to chemotherapy, irrespective of the survival time of the individual patient. Eighty five percent of owners expressed complete satisfaction with their decision to pursue chemotherapy and 70% believed their cat's health status improved during the first 2-weeks of treatment. Importantly, 78% of owners considered that chemotherapy required a very substantial time commitment on their part. CONCLUSIONS: It was possible to cure approximately one quarter of cats with lymphosarcoma using sequential multi-agent chemotherapy and/or surgery. FeLV-negative cats younger than 4 years (typically with mediastinal lymphosarcoma) had a particularly favourable prognosis. The decision to embark on chemotherapy should be based on the results of induction chemotherapy with l-asparaginase, vincristine and prednisolone, as the response to this was a good predictor of long-term survival. Cats surviving the first 16 weeks of chemotherapy generally enjoyed robust remissions (in excess of 1 year) or were cured of their malignancy.     

Feline leukaemia virus status of Australian cats with lymphosarcoma

OBJECTIVE: To determine the FeLV status of sera and tumours from Australian cats with lymphosarcoma in relation to patient characteristics, tumour characteristics (tissue involvement, histological grade and immunophenotype), haematological and biochemical values. DESIGN: Prospective study of 107 client-owned cats with naturally-occurring lymphosarcoma. PROCEDURE: An ELISA was used to detect FeLV p27 antigen in serum specimens collected from cats with lymphosarcoma. A PCR was used to detect FeLV DNA in formalin-fixed, paraffin-embedded tissue sections containing neoplastic lymphoid cells. The PCR was designed to amplify a highly conserved region of the untranslated long terminal repeat of FeLV provirus. RESULTS: Only 2 of 107 cats (2%), for which serum samples were available, were FeLV-positive on the basis of detectable p27 antigen in serum. In contrast, 25 of 97 tumours (26%) contained FeLV DNA. Of the 86 cats for which both PCR and ELISA data were available, 19(22%) had FeLV provirus in their tumours but no detectable circulating FeLV antigen in serum, while 2 (2%) had FeLV provirus and circulating FeLV antigen. FeLV PCR-positive/ELISA-negative cats (19) differed from PCR-negative/ELISA-negative cats (65) in having fewer B-cell tumours (P = 0.06), more non B-/non T-cell tumours (P = 0.02) and comprising fewer non-Siamese/Oriental pure-bred cats (P = 0.03). CONCLUSIONS: The prevalence of FeLV antigen or provirus was considerably lower in our cohort of cats compared with studies of lymphosarcoma conducted in the Northern hemisphere. This suggests that factors other than FeLV are important in the development of lymphosarcoma in many Australian cats. No firm conclusions could be drawn concerning whether FeLV provirus contributed to the development of lymphosarcoma in PCR-positive/ELISA-negative cats.