A neuroanatomical study of the feline brain using MRI and mulligan staining: functional and pathological considerations

BACKGROUND

Despite multiple studies describing accurate diagnoses using advanced neuroimaging techniques, low and mid-field magnetic resonance imaging (MRI) are still the most frequent scanners in veterinary clinics. To date, these studies in cats do not show a clear distinction of nerve centres in MRI data.

AIMS

The objective of this study is to determine the efficacy of Mulligan histological staining as a tool in facilitating the location and identification of the main structures of the feline brain in MRI. This study aims to facilitate the interpretation of MRI obtained with these types of scanners.

METHODS

A total of 10 feline brains were used. One specimen was used for MRI (T2 sequence using a 1.5T scanner). The other 9 brains were sectioned and stained with the three Mulligan staining techniques (Mulligan, Le Masurier and Robert).

RESULTS

The uptake of stain by the grey matter in these sections allowed the determination of the location and the limits of these nervous structures within the brain. The histological location of these structures was correlated with the MRI scans, leading to the successful identification of many small, indistinct nuclei.

CONCLUSION

Mulligan staining is proposed as a tool that facilitates the location of nerve structures in comparison with data from the most frequently-used MRI scanners in veterinary clinics.

Effect of two thermal regimes on the muscle growth dynamics of sea bass larvae, Dicentrarchus labrax L

Muscle growth was studied in larvae of sea bass, Dicentrarchus labrax L., reared at two temperatures: real ambient temperature ( congruent with 15 degrees C during vitelline phase and increased gradually) and 19 degrees C from fertilization until the end of larval development. Muscle cellularity, body length and body weight were measured. Early temperature influenced larval development and so, pre-larval phase finished earlier at 19 degrees C than at ambient temperature (4 and 6 days, respectively). Temperature also affected muscle growth such that at hatching and at mouth opening hypertrophy of muscle fibres was greater at 19 degrees C (P < 0.05), whereas hyperplasia was similar in both groups. After 25 days, the cross-sectional area of the white muscle was greater at 19 degrees C (P < 0.05), which was mainly associated with a higher proliferation of new white muscle fibres. At this stage the body length was also higher at 19 degrees C. Metamorphosis finished earlier in fish reared at 19 degrees C (52 days) than at natural temperature (82 days). At this developmental stage body length and cross-sectional area of the myotome were similar in both groups. However, muscle cellularity differed between groups. Thus, hypertrophy of muscle fibres was higher in fish reared at ambient temperature (P < 0.05), whereas proliferation of new muscle fibres was higher at 19 degrees C (P > 0.05).

Histochemical and morphometric aspects of the lateral musculature of different species of teleost marine fish of the Percomorphi order

Cross-sections of the lateral musculature of 19 species of teleost fish of the Percomorphi order were studied histochemically and morphometrically. The red, pink and white muscles were observed in all the species except in Seriola dumerilii and Scomber japonicus, in which no pink muscle was found. The red fibres were the smallest due to their minimal diameters. Histochemically and according to their location at least five types were found in the same species: typical red, in rosette, of the border, infiltrated pink and in mosaic. The pink fibres were larger than the red but smaller than the white. The form and disposition of the pink muscle varied according to the species. This muscle is made up by fibres of medium size, moderate m-ATPase and intermediate oxidative activities. Their histochemical properties change near red and white muscles, where they acquire the histochemical characteristics of the typical red fibres or the low m-ATPase activity of white fibres, respectively. The white muscle is the widest muscular layer. All of the species, except Thalassoma pavo are made up by three fibre types (small with high m-ATPase activity, medium with moderate m-ATPase activity, and large with low m-ATPase activity). They are mixed and show a histochemical and morphometric mosaic form. The extent of this mosaic depends on the species. In most of the analysed species it was observed in areas close to the pink muscle, but in three of them (Liza aurata, Seriola dumerilii and Coris julis) it occupied all of the myotome.