Structural and molecular study of the supraspinatus muscle of modern humans (Homo sapiens) and common chimpanzees (Pan troglodytes).

OBJECTIVES: To analyze the muscle architecture and the expression pattern of the myosin heavy chain (MyHC) isoforms in the supraspinatus of Pan troglodytes and Homo sapiens in order to identify differences related to their different types of locomotion. MATERIALS AND METHODS: We have analyzed nine supraspinatus muscles of Pan troglodytes and ten of Homo sapiens. For each sample, we have recorded the muscle fascicle length (MFL), the pennation angle, and the physiological cross-sectional area (PCSA). In the same samples, by real-time quantitative polymerase chain reaction, we have assessed the percentages of expression of the MyHC-I, MyHC-IIa, and MyHC-IIx isoforms. RESULTS: The mean MFL of the supraspinatus was longer (p = 0.001) and the PCSA was lower (p < 0.001) in Homo sapiens than in Pan troglodytes. Although the percentage of expression of MyHC-IIa was lower in Homo sapiens than in Pan troglodytes (p = 0.035), the combination of MyHC-IIa and MyHC-IIx was expressed at a similar percentage in the two species. DISCUSSION: The longer MFL in the human supraspinatus is associated with a faster contractile velocity, which reflects the primary function of the upper limbs in Homo sapiens-the precise manipulation of objects-an adaptation to bipedal locomotion. In contrast, the larger PCSA in Pan troglodytes is related to the important role of the supraspinatus in stabilizing the glenohumeral joint during the support phase of knuckle-walking. These functional differences of the supraspinatus in the two species are not reflected in differences in the expression of the MyHC isoforms.

Ultrastructure of Lingual Papillae in Common Chimpanzee (Pan troglodytes) Foetus, Newborn and Adult Specimens.

Among primates, the two recognized species of chimpanzees (common chimpanzee, Pan troglodytes; pygmy chimpanzee, Pan paniscus) are considered to be the most similar to humans. Importantly, in mammals, the food intake behaviour largely determines the tongue morphology, including the type, proportion and distribution of gustatory and non-gustatory tongue papillae. The lingual papillae form during its development and mature in post-natal life depending on the different feeding. In this study, we have used scanning electron microscopy to analyse the age-related changes in the lingual papillae of foetal, newborn and adult P. troglodytes. Four main types of lingual papillae, denominated filiform, fungiform, foliate and vallate, and one subtype of filiform papillae called conical papillae, were found. The main age-related changes observed in all kinds of papillae were a progressive keratinization and morphological complexity along the lifespan. During the foetal period, there was scarce keratinization, which progressively increases in young animals to adulthood. The number of filiform increased with ageing, and both filiform and fungiform papillae in adult tongues are divided into pseudopapillae. On the other hand, the vallate papillae vary from smooth simple surfaces in foetal tongues to irregular surfaces with grooves and pseudopapillae (microscopic papilla-shaped formations within the papilla itself) in adults. These results describe for the first time the age-related variations in the three-dimensional aspect of lingual papillae of the chimpanzee tongue and provide new data to characterize more precisely these structures in the human closest specie.

Functional and comparative study of lingual papillae in four species of bear (Ursidae) by scanning electron microscopy.

The eight current species of bear (Ursidae) are widely distributed throughout Europe, Asia, and America. They are mainly encountered in the northern hemisphere, except for the spectacled bear and the sun bear, which are also found in the south of the equator. Adaptations of the masticatory apparatus (teeth, tongue, and musculature) to diet are one of the factors that imply the greatest structural changes in the cranium. This diet may be carnivorous, herbivorous, melliferous, or insectivorous, with one type of food predominating according to the time of year. The way in which food is eaten determines the morphology of the lingual surface; generally speaking, all bears put their mouth to the food, which, initially, they lick or they let the food stick to their tongue, as occurs when insects are eaten. As in all mammals, a distinction can be made between mechanical and gustatory papillae and the development and distribution of which depend on the species and their eating habits. In this study of the complete tongues of four species of adult bears, we describe the morphology of the lingual surfaces, the different types of papillae, their characteristics, and topographic distribution. It was seen that there were five main types of lingual papillae: filiform, conical, fungiform, foliate, and vallate. Morphology of the microgrooves and pores was similar to that observed in other mammals. In general, there were no great differences among the four species of bears studied, perhaps due to the similarity in the kind of food they consume in captivity.

Morphological study of the lingual papillae of the giant panda (Ailuropoda melanoleuca) by scanning electron microscopy.

Due to the scarcity of giant pandas, there are few descriptions of their morphology and even fewer of their microscopic anatomy and the ultrastructure of their organs. In this study of the complete tongue of an adult male giant panda, we describe the morphology of its lingual surface, the different types of papillae, their characteristics and topographic distribution. It was seen that there are four main types of lingual papillae: filiform, conical, fungiform and vallate. There was no sign of foliate papillae, tuberculum intermolare or sublingua. Papilla distribution was not limited to the dorsum of the tongue, but was also seen on the anterior and ventral surfaces of the tongue. In the anterior third of the midline there is a smooth area with no papillae at all. Morphology of the microgrooves and pores is similar to that observed in other mammals. The papillae share characteristics encountered in Carnivora and herbivorous species of mammals. A narrow bamboo-based diet and specialized manner of eating have together resulted in modification of the tongue of a carnivoran, giving it some characteristics typical of an herbivore.

Severe renal hypouricemia secondary to hyperbilirubinemia.

A 64-year-old man with alcoholic liver cirrhosis had a progressive decrease in the serum uric acid (UA) until it became undetectable, an increase renal UA clearance, mild glycosuria with normal serum glucose and a decrease in the tubular reabsorption of phosphate in association with cholestasis secondary to a gallbladder carcinoma. All these abnormalities returned to normal when the serum bilirubin levels decreased following surgical treatment. This clinical observation suggests that the reversible renal tubular transport defect was secondary to high levels of serum bilirubin.