Wavy changes in the whiskers of domestic cats are correlated with feline leukemia virus infection.

BACKGROUND: Feline leukemia virus (FeLV) is a retrovirus with global impact on the health of domestic cats and is usually examined by serology. In our daily clinical practice, we noticed that cats infected with FeLV often possess wavy whiskers (sinus hairs on the face). To investigate the relationship between wavy whiskers (WW) and FeLV infection, the association between the presence or absence of wavy changes in whiskers and serological FeLV infection was examined in a total of 358 cats including 56 cats possessing WW, using the chi-square test. The results of blood tests from 223 cases were subjected to multivariate analysis (logistic analysis). Isolated whiskers were observed under light microscopy, and upper lip tissues (proboscis) were subjected to histopathological and immunohistochemical analyses. RESULTS: The prevalence of WW was significantly correlated with FeLV antigen positivity in the blood. Of 56 cases with WW, 50 (89.3%) were serologically positive for FeLV. The significant association between WW and serological FeLV positivity was also confirmed by multivariate analysis. In WW, narrowing, degeneration, and tearing of the hair medulla were observed. Mild infiltration of mononuclear cells in the tissues, but no degeneration or necrosis, was found. By immunohistochemistry, FeLV antigens (p27, gp70 and p15E) were observed in various epithelial cells including the sinus hair follicular epithelium of the whisker. CONCLUSIONS: The data suggest that the wavy changes in whiskers, a unique and distinctive external sign on a cat's face, were associated with FeLV infection.

Hoffmann reflex in a rat bipedal walking model.

The rat bipedal walking model (RBWM) refers to rats that acquired anatomical and functional characteristics for bipedal walking after the completion of a long-term motor training program. We recorded the Hoffmann reflex (H-reflex) of the forelimb and hindlimb in RBWM and control (not trained, normal) rats to evaluate the effects of bipedal walking on central nervous system (CNS) activity. The H-reflex recorded from the hindlimbs of the RBWM was significantly inhibited compared with that in the control. Furthermore, the inhibition of the H-reflex recorded from both forelimbs and hindlimbs by paired pulse stimulation tended to be enhanced in RBWM. These results indicate that bipedal walking or bipedal walking training cause functional changes in spinal reflex pathways in the CNS.

The polysynaptic pathways from the low threshold cutaneous afferents of the trunk to motoneurons innervating hindlimb muscles in the spinal cat.

We studied the reflex actions of the cutaneous afferents innervating the trunk to hindlimb motoneurons in the spinal cat using an intracellular recording technique. Stimulation of the trunk cutaneous afferents entering into the L2-L5 spinal segment produced different types of polysynaptic potentials in hindlimb motoneurons via polysynaptic neuronal pathways. The trunk cutaneous afferents predominantly caused excitatory PSPs in the flexor motoneurons and inhibitory PSPs in the extensor motoneurons. The size and latency of polysynaptic potentials were related to the proximity of the spinal segments of the nerves stimulated to the spinal segments of motoneurons. These findings suggest that the neuronal pathways from trunk cutaneous afferents to hindlimb motoneurons play an important role in coordinating between the trunk and hindlimbs.

Characteristics of H- and M-waves recorded from rat forelimbs.

The Hoffman reflex (H-reflex) is a useful tool for studying the functional aspects of the spinal cord without anesthesia and/or damage to the body. H-reflex studies are performed mainly in the hindlimbs. The purpose of the present study was to evaluate the characteristics of the H-reflex in the forelimbs and hindlimbs in rats anesthetized with ketamine-HCl. H- and M-waves were recorded from the interosseous muscles after electrical stimulation of the n. lateral plantar of the hindlimb and n. medialis of the forelimb. Hmax/Mmax values were significantly smaller in the forelimbs than in the hindlimbs. Furthermore, paired-pulse attenuation tended to be stronger in the forelimbs than in the hindlimbs. These findings suggest that control by descending and/or propriospinal pathways is stronger in the forelimbs than in the hindlimbs in rats.