Nervous System

The pathology of canine mammary candidiasis with embolic dissemination in a dog

Candidiasis is a fungal disease caused by Candida albicans or other members of the genus Candida. Descriptions of candidiasis are comparatively reduced in veterinary relative to human medicine, with no cases of mammary candidiasis being identified in pet animals. This report presents the cytological, pathological, and molecular findings of mammary candidiasis with embolic dissemination in a postpartum dog. A 1-year-old, female Shih-tzu dog that had recently given birth was admitted to a veterinary teaching hospital in Southern Brazil after repeated episodes of intermittent mammary disease and a neurological syndrome. The dog was euthanized due to worsened clinical status and poor prognosis despite adequate clinical therapy and was submitted for routine post-mortem evaluation to determine the cause of the neurological manifestations. Cytological analysis of purulent mastitis identified intralesional fungal hyphae. Gross evaluation revealed multiple masses within the kidneys, liver, myocardium, pancreas, and brain. Routine histopathology and histochemistry identified fungal nephritis, hepatitis, myocarditis, pancreatitis, and encephalitis associated with intralesional fungal hyphae, frequently with fungal emboli and vasculitis. Pure cultures of C. albicans were obtained from fragments of the masses observed at the myocardium and kidneys, with the typical germ tube of C. albicans being identified by microscopic evaluation. A PCR assay that targeted the ITS1 and 4 generic regions of fungi, amplified the desired amplicon, and direct sequencing confirmed C. albicans. Immunohistochemical and molecular assays designed to identify common infectious disease pathogens of dogs did not confirm the participation of canine distemper virus, canine parvovirus, or canine adenovirus in the target tissues of this dog. These findings suggest that this dog suffered an initial cutaneous lesion, that probably served as portal of entry to the mammary gland, resulting in mammary candidiasis with subsequent embolic dissemination to multiple organs. This report represent the first description of mammary candidiasis in pet animals and probably one of the few pathological descriptions of mammary candidiasis in domestic animals. In this case, the cause of the fungal infection was probably associated with factors intrinsic to abdominal surgery, pregnancy, and the utilization of antibiotics.

The sound stimulation method and EEG change analysis for development of digital therapeutics that can stimulate the nervous system: Cortical activation and drug substitution potential

INTRODUCTION

The purpose of this study is to propose a treatment method and the effect on the nervous system of digital therapeutics, which is a new treatment method to replace surgery and drug prescription for the treatment and prevention of diseases.

METHODS

The 20 subjects who participated in the experiment, including men and women, had an average age of 26 ± 2.40 years. The proposed treatment method used three types of sound stimulation and air or bone conduction sound transmission methods to induce total of 6-time EEG electroencephalogram(EEG) changes. EEG was measured with 200 sampling rate each in the P4, Cz, F8 and T7 channel located in the parietal, central, frontal and temporal lobes, respectively, according to the 10/10 system. A total of 2 min of data were created by extracting EEG signals with less noise from the measured data and the extracted data were applied with a 1-40 Hz Butterworth filter and a 50 Hz notch filter with a quality factor of 30. After that, EEG are subdivided into delta (0.5-4 Hz), theta (4-8 Hz), alpha (8-13 Hz), beta (13-30 Hz), and gamma (30-45 Hz) bands. Finally, EEG changes in response to sound stimuli were analyzed using power spectral density and T-test validation in the frequency band.

RESULTS

When a sound stimulus of less than 1 KHz was stimulated by air conduction, brainstem activation was induced and the reticular activation system was activated. In addition, a great potential for replacing drugs was confirmed by inducing changes in the nervous system similar to drugs used for sedation.

CONCLUSION

These results will be able to expand the concept of digital therapeutics, and it is expected that it will be developed as a safer treatment method that can replace surgery and drugs.

Medroxyprogesterone acetate in reindeer bulls: testes histology, cfos activity in the brain, breeding success, and semen quality

A previous study reported that a 400-mg dose of medroxyprogesterone acetate (MPA) reduced male reindeer aggression and blocked development of secondary sexual characteristics but did not completely impair fertility. Here we have repeated that protocol in two separate trials. In 2017, tissues and blood samples, collected from MPA and control (CTL) reindeer bulls, euthanized at 30 and 60 d post-treatment were used to evaluate testes histology and morphometrics, cfos activity in the brain and androgen levels. While testes weight tended to decline from August to September in both groups, indices of spermatogenesis remained high. By September, indices of spermatogenesis were declining in both groups with sperm density lower (P = 0.05) in MPA compared to CTL bulls. Aug CTL bulls had the highest concentrations of androstenedione (A4) (P = 0.009) and testosterone (T) (P = 0.08), whereas these androgens were baseline in Aug MPA bulls. By September, A4 and T levels in CTL bulls declined to levels measured in MPA bulls. Cfos activity had a greater number (P = 0.02) of cfos positive neurons in the central amygdala in MPA compared to CTL bulls, suggesting a heightened fear response among the MPA bulls. In the second trial (2019), MPA-treated bulls, with (E, n = 4) and without (IE, n = 4) breeding experience, were blood sampled at key points from July through September when they were put in individual harems with estrous-synchronized cows. Concentrations of T were greatest (P < 0.001) among E bulls prior to MPA treatment but 1 mo after treatment, both T and A4 were baseline in all eight reindeer. Semen collected by electroejaculation at 60 d post-MPA treatment revealed only minor differences in sperm abnormalities between E and IE bulls using both fresh and frozen/thawed semen. Only three bulls (2 E and 1 IE) sired offspring. Breeding success was not related to previous breeding experience, body weight, or bull age. The failure of some MPA bulls to breed appears to be a behavioral, not a physiological, limitation. Limited application of MPA is clearly a useful tool for managing rut-aggression in non-breeding reindeer. However, the possibility that semen could be collected from MPA-treated bulls using restraint and mild sedation rather than general anesthesia should be investigated. This could improve the quality of semen collection while enhancing the safety of both handlers and animals.

A Case of Leporine Dysautonomia from Croatia

Leporine dysautonomia (or dysautonomia of hares) is an idiopathic disorder associated with degeneration of neurons of the peripheral nervous system with loss of sympathetic and parasympathetic nerve function. The disease has so far been described in rabbits and hares from Great Britain, and a similar disorder has also been described in horses (grass sickness), dogs and cats (Key-Gaskell syndrome) throughout the world.

We describe a case of leporine dysautonomia in a rabbit from Croatia, characterized by gross findings of cachexia, dehydration, dilated intestines and urinary bladder. Histologic findings included severe vacuolation of neurons of the submucous and myenteric plexus in the intestinal tract.

This disease presents a rare disorder of rabbits, and based on current report, it should be considered as a possible differential diagnosis is rabbits with neurologic clinical signs and mild gross findings including cachexia and distension of intestine and urinary bladder.

Considerations about Hypoxic Changes in Neuraxis Tissue Injuries and Recovery

Hypoxia represents the temporary or longer-term decrease or deprivation of oxygen in organs, tissues, and cells after oxygen supply drops or its excessive consumption. Hypoxia can be (para)-physiological-adaptive-or pathological. Thereby, the mechanisms of hypoxia have many implications, such as in adaptive processes of normal cells, but to the survival of neoplastic ones, too. Ischemia differs from hypoxia as it means a transient or permanent interruption or reduction of the blood supply in a given region or tissue and consequently a poor provision with oxygen and energetic substratum-inflammation and oxidative stress damages generating factors. Considering the implications of hypoxia on nerve tissue cells that go through different ischemic processes, in this paper, we will detail the molecular mechanisms by which such structures feel and adapt to hypoxia. We will present the hypoxic mechanisms and changes in the CNS. Also, we aimed to evaluate acute, subacute, and chronic central nervous hypoxic-ischemic changes, hoping to understand better and systematize some neuro-muscular recovery methods necessary to regain individual independence. To establish the link between CNS hypoxia, ischemic-lesional mechanisms, and neuro-motor and related recovery, we performed a systematic literature review following the" Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA") filtering method by interrogating five international medical renown databases, using, contextually, specific keywords combinations/"syntaxes", with supplementation of the afferent documentation through an amount of freely discovered, also contributive, bibliographic resources. As a result, 45 papers were eligible according to the PRISMA-inspired selection approach, thus covering information on both: intimate/molecular path-physiological specific mechanisms and, respectively, consequent clinical conditions. Such a systematic process is meant to help us construct an article structure skeleton giving a primary objective input about the assembly of the literature background to be approached, summarised, and synthesized. The afferent contextual search (by keywords combination/syntaxes) we have fulfilled considerably reduced the number of obtained articles. We consider this systematic literature review is warranted as hypoxia's mechanisms have opened new perspectives for understanding ischemic changes in the CNS neuraxis tissue/cells, starting at the intracellular level and continuing with experimental research to recover the consequent clinical-functional deficits better.

Anatomical description of the ventral and dorsal cervical rootlets in rats: A microsurgical study

Purpose:

To describe the anatomical aspects of the cervical rootlets and to quantify the number of rootlets that compose C1 to T1.

Methods:

Twenty male rats were used in this study. The dorsal rootlets from C1 to T1 were analyzed. To study the ventral rootlets, the posterior root avulsion was performed using a microhook, allowing exposure of the ventral roots through manipulation of the denticulate ligament and arachnoid mater. The parameters analyzed were the number of ventral and dorsal rootlets by side and level.

Results:

The formation of the respective spinal nerve was observed in the spinal roots the union of the ventral and dorsal roots. In four animals the C1 spinal root had no dorsal and/or ventral contribution. There is no normal pattern of numerical normality of the dorsal and ventral rootlets. The average number of fascicles per root was 4.08, with a slight superiority on the left side. There was a slight superiority of the dorsal rootlets compared to the ventral rootlets.

Conclusions:

This investigation was the first to study cervical rootlets in rats. In 20% of the sample studied, the dorsal root of C1 was absent mainly on the left side. There is a nonlinear numerical increase from C1 to T1 in the rootlets. There is a numerical predominance of cervical fascicles on the left side, confronting several studies related to the functional predominance of right laterality, requiring new studies that correlate these variables.

Spontaneous Axonal Dystrophy in the Brain and Spinal Cord in Naïve Beagle Dogs

Axonal dystrophy (AD) is a common age-related neurohistological finding in vertebrates that can be congenital or induced by xenobiotics, vitamin E deficiency, or trauma/compression. To understand the incidence and location of AD as a background finding in Beagle dogs used in routine toxicity studies, we examined central nervous system (CNS) and selected peripheral nervous system (PNS) tissues in twenty 18- to 24-month-old and ten 4- to 5-year-old control males and females. Both sexes were equally affected. The cuneate, gracile, and cochlear nuclei and the cerebellar white matter (rostral vermis) were the most common locations for AD. Incidence of AD increased with age in the cuneate nucleus, cerebellar white matter (rostral vermis), trigeminal nuclei/tracts, and lumbar spinal cord. Axonal dystrophy in the CNS was not accompanied by neuronal degeneration/necrosis, nerve fiber degeneration, and/or glial reaction. Axonal dystrophy was not observed in the PNS (sciatic nerve, vagus nerve branches, or gastrointestinal mural autonomic plexuses).

Synchysis scintillans of the anterior chamber in a dog

Intraocular cholesterol granuloma (CG) associated with synchysis scintillans (SS) was diagnosed in a 5-year-old spayed Shetland sheepdog. During the initial clinical examination, the patient exhibited SS in the anterior chamber. Canine SS is usually found in the vitreous cavity, and SS in the anterior chamber has not been described. Since canine SS has been reported to be a non-progressive condition, and its long-term clinical course has not been adequately documented. The present case report describes the long-term clinical course of a case of canine SS, in which SS occurred in the anterior chamber, leading to intraocular CG formation, and eventually glaucoma.

Globoid cell leukodystrophy (Krabbe disease) in a Merino sheep

We describe the clinicopathologic features of an ovine case of Krabbe disease (globoid cell leukodystrophy). Brain lesions, sometimes bilaterally distributed, were present in the cerebellar peduncles, cerebellar folia white matter, medulla, pons, and spinal cord and characterized by marked myelin loss and numerous large macrophages (globoid cells), which tended to aggregate perivascularly. Gemistocytic astrocytes were abundant, and their nuclei were frequently abnormal. The activity of the deficient enzyme, galactosylceramide β-galactosidase, was undetectable in this neurologic disorder compared to age- and breed-matched control brains, and levels of the neurotoxic substrate, psychosine, were markedly elevated.