Carlos Henrique de Freitas Burity

Stereology of the Liver in Three Species of Leontopithecus (Lesson, 1840) Callitrichidae – Primates

Studies on liver morphology and stereology are relevant to the comparative anatomical and pathological research. They also facilitate the use of non‐human primates in basic research, which has substantially supported studies in human medicine. Quantitative studies of liver structures have also been more extensive in Old World primates and other vertebrates. Twenty‐three livers of adult lion tamarins were studied (six Leontopithecus rosalia, seven Leontopithecus chrysomelas, and 10 Leontopithecus chrysopygus), dissected, and fixed in 10% neutral buffered formalin solution. For stereological quantification, the liver was regarded as consisting of parenchyma (hepatocytes) and stroma (non‐hepatocytes). The volume density (Vv) was determined by point counting, and the disector method was used to obtain the numerical density of hepatocytes (Nv). Hepatic stereological differences among the three species of lion tamarins were not statistically significant. Therefore, the pooled Vv[hepatocyte] and Vv[stroma] could be determined as 96.2 and 7.4%, respectively, and Nv[hepatocyte] as 500.33 × 106 cm−3 . Significantly different, the values found for Vv[hepatocyte] and Nv[hepatocyte] in lion tamarins were, respectively, 0.09 and 2.8 times greater than those in baboons, and 0.17 and 3.8 times greater than those in man. However, the Vv[stroma] was 1.04 times smaller than that in baboons and 1.79 times smaller than that in man.

Stereology of the myocardium in two species of Callithrix (Callitrichidae, Primates)

The majority of studies on cardiac morphology have concentrated on Old World monkeys. Ten marmoset hearts of the genus Callithrix were studied (5 hearts of C. jacchus and 5 of C. penicillata), dissected and fixed in a 10% buffered formaldehyde solution, pH 7.2. Unbiased stereological estimates were obtained from isotropic uniform random sections of the myocardium. For stereological quantification the myocardium was regarded as consisting of cardiac myocytes and interstitium. The volume density (Vv) was determined by point counting. We used the disector method to obtain the numerical density of the cardiac myocytes (Nv[nuclei]). Myocardial stereological differences between the two species of marmoset were not statistically significant. We can therefore determine the pooled Vv[myocyte] and Nv[nuclei] as 68.6% and 41.6% (10(3)/mm3) respectively. The values found for Vv[myocyte] and Nv[nuclei] in the marmoset are respectively about 23.0 and 92.0% greater than those of the baboon, and respectively 57.3 and 45.5% greater than those in man. In contrast, the mean myocyte volume in the marmoset is not significantly different to that of man but is almost 36.0% less than that of the baboon.

Scanning electron microscopic study of the tongue in golden-headed lion tamarins, Leontopithecus chrysomelas (Callithrichidae: Primates)

Leontopithecus is the largest genus of Callithrichidae, occupying isolated remnants of the Atlantic Forest in Brazil. The objective of this study was to investigate the ultrastructure of the dorsum of the tongue of golden-headed lion tamarins. Tongues of ten adult lion tamarins kept in captivity at the Center of Primatology of Rio de Janeiro (CPRJ-FEEMA) were analyzed under scanning electron microscopy. The three vallate papillae were distributed in a V shape, and each papilla was surrounded by a deep sulcus and an external pad; the medial papilla showed a round shape and the lateral one was elliptical. The filiform papillae were shaped as a crown or as finger-like papillae, and were distributed throughout the tongue, including the margins, except for the posterior region. The fungiform papillae were scattered among the filiform papillae, in a disperse manner, from the apex to the lateral vallate papillae. The foliate papillae had a typical ultrastructure, with folds that ranged in number from 1 to 3. With respect to vallate papillae, we identified the microridge and pore pattern on its surface. Further studies are required to confirm the hypotheses on the ultrastructural aspects described for golden-headed lion tamarins.

Golden Lion Tamarins, Leontopithecus rosalia (Linnaeus, 1766) in the Taquara Municipal Natural Park (Duque De Caxias, Rj): A Southern Extension of the Known Range

Horwich, R. H. 1983. Breeding behaviors in the black howler monkey (Alouatta pigra) of Belize. Primates 24: 222–230. Mason, W. A. 1996. Social organization of the South American monkey, Callicebus moloch: A preliminary report. Tulane Studies in Zoology 13: 23–28. Mendes, S. L. 1989. Estudo ecológico de Alouatta fusca (Primates: Cebidae) na Estação Biológica de Caratinga, MG. Revista Nordestina de Biologia 6: 71–104. Palombit, R. A. 1994. Extra-pair copulations in a monogamous ape. Animal Behaviour 47: 721–723. Pope, T. R. 1990. The reproductive consequences of male cooperation in the red howler monkey: Paternity exclusion in multi-male and single-male troops using genetic markers. Behav. Ecol. Sociobiol. 27: 439– 446. Reichard, U. 1995. Extra-pair copulations in a monogamous gibbon (Hylobates lar). Ethology 100: 99–112. Smuts, B. B. 1987. Sexual competition and mate choice. In: Primate Societies, B. B. Smuts, D. L. Cheney, R. M. Seyfarth, R. W. Wrangham and T. T. Struhsaker (eds.), pp.385–399. The University of Chicago Press, Chicago.

Morphological and morphometric age-related changes of the upper thoracic aorta in Leontopithecus (Lesson, 1840) (callitrichidae--primates).

Few morphologic aspects of Leontopithecus are listed in the literature, which does not provide sufficient knowledge of those simians. However, such results are important to evaluate the potential of those species as a model for studying comparative pathology. In this study, the material came from the collection of the Museu de Primatologia do Centro de Primatologia do Rio de Janeiro, fixed in 10% formalin pH 7.2. The samples were 33 individuals (five infant and five adult L. rosalia, L. chrysomelas, L. chrysopygus chrysopygus, and three adult L. chrysopygus caissara). The sections of the thoracic aorta were prepared for histological study and measurements were obtained. In the infant Leontopithecus, the aorta presents endothelial line and subendothelial space, the tunica media is not comparatively very thick. In the adults, the aorta showed enlarged tunica intima with consequent thick arterial wall, which increased with the aging process. The atheromatous plates were seen in the aortic wall of all adult L. chrysopygus chrysopygus, in two adult L. rosalia and only one adult L. chrysomelas. Differences in the aortic internal and external diameters were not significant in infants. In the adults, no significant difference was found among L. rosalia, L. chrysomelas and L. c. caissara, although the average of the aortic internal diameter in L. chrysomelas was larger than in L. c. caissara. In infant and adults L. c. chrysopygus, the thickness of the thoracic aorta is larger than in the other forms of Leontopithecus. These findings suggest a morphometric and morphologic aortic difference among the species of Leontopithecus, which could have biological significance that needs major investigation in the future.

Craniometric sexual dimorphism inLeontopithecusLesson, 1840 (Callitrichidae, Primates)

Lion tamarins are among the Worlds most critically endangered primates. Many studies have been produced under guidance of the International Management Committees for the preservation and management of these tamarins. Primates present morphological sexual differences in a wide range of characteristics, including cranial morphology. Studies of sexual dimorphism in the cranial morphology of theLeontopithecus are few in number and contradictory in their results. In order to check for the existence of sexual dimorphism in lion tamarins the present study analyzed 17 craniometric distances on 56 crania of three species of lion tamarins (Leontopithecus): 20L. rosalia (14 females and 6 males); 13L. chrysomelas (6 females and 7 males); and 23L. chrysopygus (8 females and 15 males). All crania are housed in the CPRJ-FEEMA collection (Primatological Center of Rio de Janeiro) and came from animals born in captivity.L. chrysopygus was more sexually dimorphic (10/17 measurements, 59%) thanL. chrysomelas (9/17 measurements, 53%) orL. rosalia (7/17 measurements, 41%). In all three species, male values are greater than the female ones, except for orbital breadth (m7) inL. rosalia. However, this distance is not sexually dimorphic in this species. This study reveals that some cranial distances, especially in the facial region, are sexually dimorphic in lion tamarins.

Myocardial stereology in captive Callithrix kuhlii (Callitrichidae, Primates): healthy animals versus animals affected by wasting marmoset syndrome (WMS)

This study comprised 12 hearts of Wied´s black-tufted-ear marmoset, Callithrix kuhlii (Coimbra-Filho 1985), 6 with Wasting Marmoset Syndrome (WMS) and 6 non-affected. Biometry was performed after death. After necropsy, the hearts were weighed, dissected, fixed in 10% formalin solution (pH 7.2), and processed for optical microscopy at 5µm sections stained with Haematoxylin-Eosin. Quantitative analysis was performed by stereological techniques. The statistical differences between the biometrical and stereological parameters were assessed by the Mann-Whitney test. The morphometric results showed that WMS causes a significant reduction in body and cardiac weights, and also in the volume density of vessels in those animals. Further studies are necessary to understand some of the results shown here.